JP3319981B2 - Valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rocker arm having a support shaft provided between first and second support walls, a roller rotatably supported by the support shaft via a bearing, and a valve operating valve. The present invention relates to a valve train for an internal combustion engine in which the rocker arm is pressed by a pressing means in a direction of rolling contact with a cam.

[0002]

2. Description of the Related Art Conventionally, such a valve operating device has been disclosed in
No. 0286, etc., among a plurality of rocker arms, a free rocker arm that is free with respect to the engine valve when the interlocking switching means is in the interlocking release state, between the first and second support walls provided in the free rocker arm. A support shaft for supporting the roller via a bearing is provided, and a pressing means for exerting a spring force for pressing the roller against the rolling contact with the valve cam is in contact with the free rocker arm.

[0003]

However, in the above-mentioned conventional device, a receiving portion is provided at the center in the width direction of the free rocker arm in a direction parallel to the axis of the rocker shaft for swingably supporting each rocker arm. In spite of having rollers, the receiving part is located at the center in the width direction, which complicates the structure of the free rocker arm,
The free rocker arm becomes large and the weight increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a valve operating mechanism for an internal combustion engine in which the structure of a rocker arm which receives a spring force from a pressing means can be prevented from becoming complicated and large. It is intended to provide a device.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a camshaft having a plurality of valve operating cams, a plurality of rocker arms arranged adjacent to each other, and Interlocking switching means capable of switching between a state in which the rocker arm is interlocked and a state in which the interlocking is released, and a freedom to be free with respect to the engine valve when the interlocking switching means of the plurality of rocker arms is in the interlocking release state. Pressing means for exerting a spring force for pressing the rocker arm toward the valve operating cam corresponding to the free rocker arm, wherein first and second support wall portions facing each other at an interval are provided on the free rocker arm; A roller that rolls and contacts a valve cam corresponding to the free rocker arm is rotatably supported via a bearing on a support shaft provided between the two support walls. In the valve operating system for an internal combustion engine, before
Arrange other rocker arms different from the free rocker arm
Each rocker arm is arranged adjacent to one end in the direction,
The interlock switching means is formed in the other rocker arm.
Depending on the operation of the piston due to the change in hydraulic pressure in the hydraulic chamber
Switchable between interlocking and unlocking of each rocker arm
And the support shaft guides the sliding operation of the piston.
The first and second support walls are formed in a cylindrical shape.
A first support wall disposed on the other rocker arm side;
Has a first fitting hole into which one end of the support shaft is fitted.
And the other end of the support shaft is attached to the second support wall.
A second fitting hole for fitting the part is provided coaxially with the first fitting hole.
And the insertion hole communicating with the inner surface of the first fitting hole is the first support hole.
Provided in the wall portion, the opening of the insertion hole into the first fitting hole inner surface
An engaging groove is provided on the outer surface of the support shaft corresponding to the
A pin engaging with the mating groove is inserted and fixed in the insertion hole.
The receiving portion for contacting the pressing means is integrally provided below the second support wall .

According to the first aspect of the present invention, the structure of the free rocker arm can be simplified by disposing the receiving portion on the side of the roller (the lower portion of the second support wall). As a result, the free rocker arm can be prevented from increasing in size, and the inertial weight can be reduced, so that it is possible to advantageously cope with high-speed rotation of the internal combustion engine. Also the
(1) In the support wall, the pin prevents the axial movement and rotation around the axis of the support shaft from being prevented by the pin, so that the support shaft can be easily fixed. It is not limited by the receiving portion, and the load from the pressing means is less likely to act on the pin of the first support wall, so that the fixing strength of the support shaft can be increased. Further, since the support shaft is fixed to the free rocker arm on the side of the insertion of the piston (the first support wall side) provided in the interlocking switching means, the piston can be smoothly inserted into the support shaft.

[0007] According to the second aspect of the invention, in addition to the configuration of the invention described in claim 1, wherein the front Symbol receiving portion is provided
The second support wall portion, characterized in that the lubricating oil passage for lubricating oil from the oil passage provided in the support member to lubricate the bearing of the free rocker arm for supporting the free rocker arm swingably provided, which Before the invention of claim 1
In addition to the above-mentioned effects, it is possible to avoid a decrease in rigidity of the support wall due to the presence of the receiving portion despite the formation of the lubricating oil passage which is a cavity. By reducing the weight of the support wall by the receiving portion, the weight balance between the two support walls can be improved.

Further , according to the third aspect of the present invention ,
In addition to the configuration of the invention described in Item 2, the lubricating oil passage is provided with each rocker.
Each lock is longer than the length in the direction substantially parallel to the arm
Increase the length in the direction substantially perpendicular to the arrangement direction of the arm.
Characterized by having a cross-sectional shape
Accordingly, in addition to the effect of the invention of claim 2,
Lubricating oil passage occupies a direction parallel to the direction of the rocker arm arrangement
Space can be made as small as possible .
The size of the hook arm can be reduced.

[0009]

DETAILED 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 10 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. 3 is a plan view as viewed in the direction of the arrow 2 in FIG. 1, FIG. 3 is a sectional view taken along line 3-3 in FIG. 2, and FIG.
5 is an enlarged sectional view taken along line 5-5 of FIG. 2, FIG. 6 is a sectional view taken along line 6-6 of FIG. 2, FIG. 7 is a sectional view taken along line 7-7 of FIG. 9 is a sectional view taken along line 9-9 of FIG. 4, and FIG. 10 is a sectional view taken along line 10-10 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 V as engine valves. Stems 13 of the intake valves V are slidably fitted to guide cylinders 14 provided on the cylinder head 11, respectively. You. Retainers 15 provided at the upper ends of the stems 13 projecting upward from the respective guide cylinders 14.
A valve spring 16 surrounding each stem 13 is provided between the cylinder head 11 and the cylinder head 11, and the intake valves V are biased in a direction to close the intake valve ports 12 by the spring force of the valve springs 16 ... Is done.

Referring also to FIGS. 2 to 4, a valve gear 17 is connected to both intake valves V, V.
The valve gear 17 is connected to a crankshaft (not shown) at a reduction ratio of 1/2 and is connected to a camshaft 18 and the first drive rocker arm 1 linked and connected to one of the two intake valves V.
9, a second drive rocker arm 20 interlocked and connected to the other of the two intake valves V, a free rocker arm 21 that can be free with respect to the two intake valves V, and an axis parallel to the camshaft 18. The rocker arm includes a fixed rocker shaft 22 as a support member that supports the rocker arms 19, 20, and 21 in a common and swingable manner, and an interlocking switching unit 23 that can switch between interlocking and unlocking of the rocker arms 19 to 21. .

The camshaft 18 includes 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 in correspondence with the two intake valves V, respectively.

The high-speed valve operating cam 26 has a cam profile for opening and closing the intake valves V in the 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 projecting 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 V... In a low-speed operation range of the engine, and includes a base circular portion 25a formed in an arc shape centered on the axis of the camshaft 18. The amount of protrusion of the camshaft 18 outward from the base circle portion 25a in the radial direction is determined by the high-speed valve cam 26.
And a high portion 25b projecting from the base circular portion 25a over a central angle range narrower than the high 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. It is swingably supported.

First and second drive rocker arms 19, 2
0 are provided integrally with arms 19a, 20a extending toward the intake valves V ..., and the ends of the arms 19a, 20a abut against the upper ends of the stems 13 ... of both intake valves V .... Tappet screws 27, 27 are screwed forward and backward freely.

Rocker shaft 22 and tappet screw 2
In the first driving rocker arm 19 between 7 and open vertically so as to form ₁ first and second support walls 31 facing each other in a direction parallel to the axis of the rocker shaft 22, 31 ₂ to both sides An opening 34 is provided, and the first driving rocker arm 1 is arranged so that the cylindrical roller 28 that is in rolling contact with the low-speed valve operating cam 25 is disposed in the opening 34.
9 rotatably supported. Also the second drive rocker arm 20 between the rocker shaft 22 and the tappet screws 27, to form first and second support walls 32 ₁ facing each other in a direction parallel to the axis of the rocker shaft 22, 32 ₂ to both sides The opening 35 which is opened up and down in this way is provided, and the cylindrical roller 29 which is in rolling contact with the low speed valve operating cam 25 is arranged in the opening 35 so as to be in the second position.
The drive rocker arm 20 is rotatably supported. More free rocker arm 21, the opposite side and up and down with the rocker shaft 22 so as to form first and second support wall portions 33 facing each other in a direction parallel to the axis ₁ of the rocker shaft 22, 33 ₂ to both sides An opening 36 is provided in the opening 36, and the cylindrical roller 30 that is in rolling contact with the high-speed valve operating cam 26 is rotatably supported by the free rocker arm 21 so as to be disposed in the opening 36.

[0018] The first support wall 37 ₁ in the first driving rocker arm 19, the free rocker arm 21 side first fitting hole 37 ₁ of the open bottom of the is provided parallel to the axis of the rocker shaft 22, the second the support wall 37 _2, the second fitting hole 37 ₂ which is open at both ends is provided with the first fitting bore 37 ₁ coaxially. First fitting hole 38 ₁ in the first support wall 32 ₁ is a free rocker arm 21 side in the second driving rocker arm 20 which is open at both ends is provided parallel to the axis of the rocker shaft 22, the second support wall portions 32 ₂ second fitting hole 38 ₂ of a bottomed opening the free rocker arm 21 side are provided in the first fitting hole 38 ₁ coaxially to. First fitting hole 39 ₁ in the first support wall 33 ₁ is a first driving rocker arm 19 side which is open at both ends is provided parallel to the axis of the rocker shaft 22 in the free rocker arm 21, the second support wall portions 33
The _{2, 2} second fitting hole 39 which is open at both ends is provided with the first fitting bore 39 ₁ coaxially.

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.

[0020] Referring also to FIG. 5, the second support wall 31 ₂ of the first driving rocker arm 19, the rocker shaft 2
Insertion holes 4 connecting the 2 and second fitting holes 37 _{and second} axis extends in a direction intersecting with the straight line leading to the second fitting hole 37 ₂ of the inner surface
4 is provided, the insertion hole 4 of the second fitting hole 37 ₂ of the inner surface
4 corresponding to the opening of the support shaft 41,
An engagement groove 50 extending along the tangential direction of the imaginary circle C about the axis of is provided. A pin 47 is inserted and fixed to the insertion hole 44 by, for example, press-fitting so that the intermediate portion is engaged with the engagement groove 50, whereby the support shaft 41 is moved to the first position.
It is fixed to the drive rocker arm 19.

[0021] 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, inserted into the insertion hole 45 provided in the first support wall 32 ₁ of the second driving rocker arm 20, the pin 48 is to be fixed,
The engaging shaft 51 is engaged with the engaging groove 51 provided on the outer surface of the support shaft 42 fitted in the first fitting hole 38 ₁ .

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
Pin 49 which is inserted and fixed in an insertion hole 46 provided in
But is engaged with the engaging groove 52 provided on the outer surface of the support shaft 43 is fitted to the first fitting hole 39 _1.

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

In FIG. 6, below the free rocker arm 21, the cylinder head 11 is provided as a pressing means for applying a spring force in the direction of rolling the roller 30 of the free rocker arm 21 to the high-speed valve cam 26 on the free rocker arm 21. The lost motion mechanism 58 is provided with a bottomed cylindrical lifter 60 whose upper part is opened and which is slidably fitted in a bottomed sliding hole 59 provided in the cylinder head 11. And a spring 6 provided between the closed end of the sliding hole 59 and the lifter 60.
And 1.

On the other hand, the free rocker arm 21 receives the spring force from the lost motion mechanism 58 to lift the lifter 60.
Although it provided with a receiving portion 62 that contacts the upper end of the receiving portion 62, first and second support walls 33 _1, 33 the first support wall portion 33 of the ₂ free rocker arm 21 is provided with
₁ the pin 49 is inserted to secure the support shaft 43, whereas the fixed, is provided integrally with raised beneath the bottom of the second support wall 33 _2.

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 the interlocking and releasing of the free rocker arm 21 and the second drive rocker arm 20 adjacent to each other;
The switching member 64 includes a bottomed cylindrical regulating member 65 that contacts the switching piston 64 on the opposite side, and a return spring 66 that biases 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. In the rocker shaft 22, an oil passage 68 connected to a hydraulic pressure source via a control valve (not shown) is provided, for example, coaxially. 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 is always communicated with the oil passage 68.

Referring to FIG. 7 as well, the communication path 70 is arranged in the direction in which the rocker arms 19 to 21 are arranged, ie, 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 the 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 swinging state of the first drive rocker arm 19. In order for the oil passage 68 to always communicate with the communication passage 70, the communication passage 70 is connected to the rocker shaft 22.
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 is open to the side of the first drive rocker arm 19, and an intermediate portion of the communication passage 70 is blocked by the rocker shaft 22.

Referring also to FIG. 8, in the first drive rocker arm 19, a bulging portion 19b bulging outward to form the communication passage 70 is formed on an outer surface on one end side in the arrangement direction of the rocker arms 19 to 21. And a plurality of, for example, two ribs 71, between the side edge 19c of the outer surface of the first drive rocker arm 19 and the bulging portion 19b.
71 are provided.

The communication passage 70 has a part that extends in a direction parallel to the axis of the rocker shaft 22.
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 regulating 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 abut against the control member 65 and prevent the control member 65 from dropping off the support shaft 42. Return spring 66
Corresponds to the 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 such an interlocking switching means 23, in a 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 V are driven to open and close at the timing and the 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 integrally connected, and the two intake valves V are driven to open and close at a timing and a lift amount corresponding to the high-speed valve operating cam 26.

[0035] Figure 9 and with reference to also to FIG. 10, two support walls 33 of the free rocker arm 21 _1, 33 side receiving portion 62 of the _two is provided, that is, the second support wall 33 ₂
The provided 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 A groove 77 having one end connected to one end of the lubricating oil passage 76 and the other end open to the bearing 55 is provided.

Further, the lubricating oil passage 76 has a cross section having a length in a direction substantially orthogonal 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.

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 the valve operating load.
While 43 is fixed, both ends of the support shafts 41 to 43, the first fitting hole 37 _1, 3 the rocker arms 19 to 21 are provided
8 _1, 39 ₁ and second fitting holes 37 _2, 38 _2, 39 ₂
Respectively. Moreover, the first drive rocker arm 1
9, the pin 47 inserted and fixed in the insertion hole 44 provided in the second support wall 31 ₂ is engaged with the engagement groove 50 of the support shaft 41, and the first support wall 32 of the second drive rocker arm 20. ₁
The pin 48 inserted and fixed in the insertion hole 45 provided in the lock shaft is engaged with the engagement groove 51 of the support shaft 42, and the free rocker arm 2.
Inserted into the first support wall portion 33 insertion hole 46 provided in the _first 1, by a pin 49 that is fixed is engaged with the engaging groove 52 of the support shaft 43, axial movement of the axles 41 to 43 And rotation around the axis is prevented, so that the support shafts 41 to 4
3 can be fixed to each of the rocker arms 19 to 21 with a simple structure.

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 connected to 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. Accordingly, 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.

[0040] Moreover in the first driving rocker arm 19, the first fitting hole 37 one end portion of the support shaft 41 of the first support wall 31 _1
1 and the support shaft 41 is attached to the first drive rocker arm 1.
Although 9 than it is secured to, by the communication passage 70 is provided in the first driving rocker arm 19 in the first support wall portion 31 ₁ side, a first support for fixing the support shaft 41 supporting the rollers 28 it is possible to arrange the communication passage 70 in the first driving rocker arm 19 to avoid that the wall portion 31 ₁ of the thickness is increased. Moreover, a notch 72 having a shape corresponding to the communication passage 70 is provided at a portion corresponding to the communication passage 70 at one end of the support shaft 41, so that the first support wall portion 31 ₁ of the first drive rocker arm 19 is provided. the first support shaft 41 is sufficiently secured contact area of the support shaft 41 of the first fitting hole 37 ₁
The communication path 70 can be arranged closer to the roller 28 side while securing the support strength to the drive rocker arm 19, so that the size of the first drive rocker arm 19 can be further 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 at one end of the first drive rocker arm 19 along the axial direction of the rocker shaft 22.
In addition, a bulging portion 19b bulging outward to form a zero is provided, and ribs 71, 71 connecting the side edge portion 19c 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, a space for providing the insertion hole 44 can be secured, and the insertion hole 44 is provided at a position relatively distant from the communication passage 70 which is a cavity, which is advantageous in terms of rigidity of the first drive rocker arm 19.

In the free rocker arm 21, the second fitting hole 3
9 ₂ of the inner surface is opened at one end lubricating oil passage 76 is provided in communication with the oil passage 68 of the rocker shaft 22, the second fitting hole 3
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 a 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.

Moreover, the lubricating oil passage 76 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 longer than the length in a direction substantially parallel to the arrangement direction of the rocker arms 19 to 21. The space occupied by the lubricating oil passage 76 in the direction parallel to the arrangement direction of the rocker arms 19 to 21 can be minimized, 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.

Further the free rocker arm 21, the lubricating oil passage 76 and the second support wall portion 33 insertion hole 46 for fixing the support shaft 43 with respect to the provided ₂ side first support wall portion 33
Since it is provided on the _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 the insertion hole 44 is provided 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.

[0049] Moreover whereas the support shaft 43 is fixed by a pin 49 in the first support wall portion 33 ₁ side, receiving unit 62 second
Since it is provided on the support wall 33 _2, inserting the pin 49, without being limited by the size and arrangement receiving part 62 of the insertion hole 46 for fixing, and load from the lost motion mechanism 58 to the pin 49 The support shaft 43
Can be increased in fixing strength. In addition, since the receiving portion 62 is provided integrally with the ₂ second support wall portion 33, even though the lubricating oil passage 76 is hollow is provided in _two second support wall portion 33, the second support it is possible to avoid a decrease in rigidity of the wall portion 33 _2, a lubricating oil passage 76
Two support walls 3 but as supplement accompanied second weight loss of the support wall portion 33 ₂ to be hollow in the receiving portion 62 the
3 _1, 33 ₂ of the weight balance can be improved.

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
Are those in which the first support wall 32 ₁ provided supported on the rocker shaft 22 so as to be disposed side first driving rocker arm 19, the timing piston 63 and the switching piston 64 of the interlocking switching means 23 is inserted Since 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 the
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. The holes 39 ₁ and 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 the above embodiment, the plurality of rocker arms 19
Although the interlocking and uncoupling of the valves 21 to 21 can be switched by the interlocking switching means 23, the present invention presses the rocker arm toward the valve operating cam with the pressing means regardless of the presence or absence of the interlocking switching means. The present invention can be applied to such a valve train of an internal combustion engine.

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.

[0054]

As described above, according to the first to third aspects of the present invention, the structure of the free rocker arm can be simplified by disposing the receiving portion on the side of the roller (the lower portion of the second support wall). In addition, the free rocker arm can be prevented from increasing in size, and the inertial weight of the free rocker arm can be reduced to advantageously cope with high-speed rotation of the internal combustion engine. Further, in the first support wall portion, the axial movement and rotation of the support shaft in the axial direction are prevented by the pins, so that the support shaft can be easily fixed . It is not limited by the receiving portion, and the load from the pressing means is less likely to act on the pin of the first support wall portion, so that the fixing strength of the support shaft can be increased.
Furthermore, the insertion side of the piston (first support
The support shaft is fixed to the free rocker arm at the holding wall portion side) , so that the piston is smoothly inserted into the support shaft.

In particular , according to the second and third aspects of the invention,
The second support wall on the side where the front Symbol receiving portion is provided, the lubricating oil passage for supplying oil to the free rocker arm bearing lubricating oil from the oil passage provided in the support member for swingably supported free rocker arm Is provided, it is possible to avoid a decrease in rigidity of the support wall due to the presence of the receiving portion despite the formation of a hollow lubricating oil passage, and the weight balance of both support walls is also improved.

Further, in particular , according to the third aspect of the present invention ,
The direction in which the lubrication path is almost parallel to the arrangement direction of each rocker arm
Is almost perpendicular to the arrangement direction of each rocker arm than the length of
Formed to have a cross-sectional shape with a large length in the direction
Lubrication in the direction parallel to the rocker arm arrangement direction
It is possible to minimize the space occupied by oil passages
Therefore, the free rocker arm can be downsized.

[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 sectional view taken along line 6-6 of FIG. 2;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 4;

FIG. 8 is a sectional view taken along line 8-8 in FIG. 2;

FIG. 9 is a sectional view taken along line 9-9 of FIG. 4;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 9;

[Explanation of symbols]

Reference Signs List 18 camshaft 19, 20 rocker arm 21 free rocker arm 22 rocker shaft as support member 25, 26 valve actuating cam 23 interlocking switching means 30 roller 33 ₁ ... First support wall portion 33 ₂ ... Second support wall portion 39 ₁ ... First fitting hole 39 ₂ . Insertion hole 49 Pins 52 Engagement grooves 55 Bearings 58 Lost motion mechanism as pressing means 62 Receivers 63, 64 Piston 67 Hydraulic chamber 68 ... oil passage 76 ... lubrication oil passage

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-65813 (JP, A) JP-A-6-221125 (JP, A) JP-A-2-38765 (JP, A) 176407 (JP, U) Japanese Utility Model Hei 7-8508 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F01L 13/00 301 F01L 1/18 F01M 1/06

Claims (3)

(57) [Claims] A camshaft (18) provided with a plurality of valve cams (25, 26), a plurality of rocker arms (19, 20, 21) arranged adjacent to each other, and a rocker arm (19) arranged adjacent to each other. , 21; 21, 20), and an interlock switching means (23) capable of switching between a state of interlocking and a state of releasing the interlocking, and the plurality of rocker arms (1).
9 to 21), the free rocker arm (21) which is free with respect to the engine valve (V) when the interlocking switching means (23) is in the interlocking release state.
And pressing means (58) for exerting a spring force for pressing the valve cam (26) corresponding to the first and second support wall portions (33 ₁ , 33 ₂ ) opposed to each other with a space therebetween. Is provided on the free rocker arm (21), and a valve operating cam (2) corresponding to the free rocker arm (21) is mounted on a support shaft (43) provided between the two support walls (33 ₁ , 33 ₂ ).
6) In a valve operating device for an internal combustion engine in which a roller (30) that comes into rolling contact with the roller (30) is rotatably supported via a bearing (55), another rocker arm different from the free rocker arm (21) is provided.
Arm (19) is arranged at one end side in the arrangement direction so that each rocker arm
(19-21) are arranged adjacent to each other,
(23) is formed in the other rocker arm (19).
Piston (6) accompanying a change in hydraulic pressure in the hydraulic chamber (67)
3, 64) according to the operation of each rocker arm (19 to 2).
It is configured to be able to switch between interlocking and uncoupling of 1).
The support shaft (43) slides the pistons (63, 64).
The first and second supports are formed in a cylindrical shape for guiding
The other rocker arm of the holding wall portion (33 ₁ , 33 ₂ )
(19) The first support wall (33 ₁ ) arranged on the side
Is a first fitting for fitting one end of the support shaft (43).
A hole (39 ₁ ) is provided and the second support wall portion is provided.
(33 ₂ ) is fitted with the other end of the support shaft (43).
The second fitting hole (39 ₂ ) is coaxial with the first fitting hole (39 ₁ ).
And is connected to the inner surface of the first fitting hole (39 ₁ ).
An insertion hole (46) is provided in the first support wall (33 ₁ ),
Opening of the insertion hole (46) into the inner surface of the first fitting hole (39 ₁ )
The engaging groove (5) is formed on the outer surface of the support shaft (43) corresponding to the opening.
2) is provided, and a pin (4) engaged with the engagement groove (52) is provided.
9) is inserted and fixed in the insertion hole (46), and the second
The lower portion of the support wall portion (33 _2), said pressing means (58)
A valve unit for an internal combustion engine, wherein a receiving part (62) for contacting the internal combustion engine is provided integrally. 2. The device according to claim 1, wherein said receiving portion (62) is provided.
A second support wall (33 _2), a free rocker arm (21)
Oil passage provided on support member (22) for swingably supporting
The lubricating oil from (68) is applied to the free rocker arm (21).
A lubricating oil passage (76) for supplying oil to the ring (55) is provided.
Characterized in that it is provided, a valve operating system for an internal combustion engine according to claim 1. 3. The lubricating oil passage (76) is provided with each rocker arm.
Length in a direction substantially parallel to the arrangement direction of the
The rocker arm (19-21)
To have a cross-sectional shape with a large length in the intersecting direction
Characterized in that it is formed, a valve operating system for an internal combustion engine according to claim 2, wherein.