JPH0736082Y2 - Valve operating system for multi-cylinder internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention (1) Field of Industrial Application The present invention relates to a valve train for a multi-cylinder internal combustion engine, and more particularly to a cylinder block in which a plurality of cylinders are arranged in series. On a cam shaft rotatably supported by a head and a cam holder fastened to the cylinder head, cams are fixedly mounted corresponding to the respective cylinders, and on a rocker shaft fixedly supported by the cylinder head, A plurality of rocker arms that respond to the rotation of the cam are supported corresponding to the engine valves of each cylinder, and hydraulic valve operation changing means that can change the opening / closing operation mode of each engine valve according to the oil pressure is arranged in each cylinder. The present invention relates to a valve operating system for a multi-cylinder internal combustion engine in which oil supply passages that are provided at intervals and extend along the arrangement direction of each cylinder communicate with the respective hydraulic valve operation changing means.

(2) Conventional Technology Conventionally, such a valve operating device is known, for example, from Japanese Patent Laid-Open No. 62-121813.

(3) Problems to be Solved by the Invention However, in the above-mentioned conventional one, a switching valve for switching between supply and cutoff of hydraulic oil to the oil supply passage along the arrangement direction of each cylinder is provided at one end side of the oil supply passage. Has been done. Therefore, the hydraulic valve operation changing means for supplying the operating oil pressure is arranged at a plurality of positions spaced in the arrangement direction of each cylinder,
Since the hydraulic pressure is supplied to and released from the oil supply passage at one end of the oil supply passage, a time lag may occur in the operation timing of each hydraulic valve operation changing means, that is, the change timing of the opening / closing operation mode of the engine valve in each cylinder.

The present invention has been made in view of the above circumstances, and it is necessary to avoid the occurrence of deviations in the operation timings of a plurality of hydraulic valve operation changing means at positions spaced in the arrangement direction of each cylinder. An object of the present invention is to provide a valve operating system for a multi-cylinder internal combustion engine as described above.

B. Device Configuration (1) Means for Solving the Problems In order to achieve the above object, according to the present invention, a cam holder at a substantially central portion along the arrangement direction of each cylinder communicates with a hydraulic pressure supply source. A hydraulic supply passage and an oil supply port communicating with substantially the center of the oil supply passage along the axial direction are provided on the upper surface of the cam holder, and the upper surface of the cam holder communicates with or cuts off the hydraulic supply passage and the oil supply opening. A switching valve that can switch between is installed.

(2) Operation According to the above configuration, the difference in the distance from the switching valve to each hydraulic valve operation changing means becomes smaller than that of the conventional one, and therefore the hydraulic pressure supply to each hydraulic valve operation changing means and each hydraulic valve. The time difference of hydraulic pressure release from the operation change means becomes small,
It is possible to avoid deviations in the timing of changing the operation mode of the engine valve in each cylinder.

(3) Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1 and FIG. 2, in this DOHC type multi-cylinder internal combustion engine, four cylinders 2 are arranged in series in a cylinder block 1. Combustion chambers 5 are defined between a cylinder head 3 that is provided side by side and is coupled to the upper end of the cylinder block 1, and a piston 4 that is slidably fitted in each cylinder 2. Further, the cylinder head 3 is provided with a pair of intake ports 6 and a pair of exhaust ports 7 in the portion forming the ceiling surface of each combustion chamber 5, and each intake port 6 is opened on one side surface of the cylinder head 3. Connected to the intake port 8, and each exhaust port 7 is connected to an exhaust port 9 opening on the other side surface of the cylinder head 3.

In the portion corresponding to each cylinder 2 of the cylinder head 3,
Intake valve 10 as a pair of engine valves that can open and close each intake port 6
i and an exhaust valve 10e as a pair of engine valves capable of opening and closing each exhaust port 7 are fitted and fixed with guide cylinders 11i and 11e, respectively, and are guided upward from the guide cylinders 11i and 11e. The valve springs 13i, 13e are respectively compressed between the flanges 12i, 12e provided at the upper ends of the intake valves 10i and the exhaust valves 10e protruding to the cylinder head 3 and the valve springs 13i, 13e. 13e for each intake valve 10i and each exhaust valve 10e
Is urged upward, that is, in the valve closing direction.

A working chamber 15 is defined between the cylinder head 3 and a head cover 14 connected to the upper end of the cylinder head 3.
In the working chamber 15, intake valves 10i in each cylinder 2 are installed.
An intake side valve operating device 17i for opening and closing the exhaust valve and an exhaust side valve operating device 17e for opening and closing the exhaust valve 10e in each cylinder 2 are housed and arranged. Double valve device 17i, 17e
Have basically the same configuration, and in the following description, one of the two valve operating devices 17i, 17e will be described in detail by adding a subscript i or e to the reference numeral, and the other will be denoted by the reference numeral. Is added only with the subscript e or i.

Referring to FIG. 3 and FIG. 4 together, the intake side valve operating device
Reference numeral 17i denotes a cam shaft 18i that is rotationally driven from a crankshaft (not shown) of the engine at a speed reduction ratio of 1/2, low speed cams 19i and 20i provided on the cam shaft 18i corresponding to each cylinder 2, and High-speed cam 21i and camshaft 18i
A rocker shaft 22i fixedly arranged in parallel with the cylinder 2, a first drive rocker arm 23i, a second drive rocker arm 24i and a free rocker arm 25i pivotally supported by the rocker shaft 22i corresponding to each cylinder 2, and each cylinder 2 A hydraulic connection switching mechanism 26i as hydraulic valve operation changing means provided between the corresponding rocker arms 23i, 24i, 25i.

Referring also to FIG. 5, the cam shaft 18i is arranged above the cylinder head 3 so as to be parallel to the arrangement direction of the cylinders 2 and to be rotatable around its axis. That is, the cylinder head 3 is integrally provided with cam support portions 27, 27 at both end portions along the arrangement direction of each cylinder 2, and three cam support portions 28 ... Are provided at positions corresponding to each cylinder 2. Cam holders 29, 29 which are integrally provided respectively and which are respectively fastened on the cam supporting portions 27, 27 at both ends, and 3
Cam holders that are fastened on the two cam supports 28 ...
The cam shaft 18i is rotatably supported around the axis by 30 and the cam supporting portions 27, 27, 28. A semi-circular support surface 31 for supporting the outer peripheral surface of the lower half of the cam shafts 18i, 18e is provided on the upper surface of each cam support portion 27, 27, 28 ..., And on the lower surface of each cam holder 29, 30, Camshaft 18
Semicircular support surface 32 for supporting the outer peripheral surface of the upper half of i, 18e
Are provided respectively.

Further, insertion holes 34 for inserting bolts 33 for fastening the cylinder head 3 to the cylinder block 1 are formed in the respective cam support portions 27, 27, 28 ... Up and down one by one at positions corresponding to the cam shafts 18i, 18e. The operation hole 35 for rotating the bolt 33 is provided at an upper position corresponding to the insertion hole 34 while extending upward and downward while opening the upper end to the semicircular support surface 31. To be done.

A cylindrical central block 36 extending vertically is integrally provided on the cylinder head 3 at a portion corresponding to the central portion of each cylinder 2 between the cam support portions 27, 27, 28. 36 and the cam support portions 27, 27, 28 on both sides are supporting walls
37 connected to each other. Further, the head cover 14 is provided with a cylindrical central block 49 connected to the central block 36. A plug insertion hole 38 is formed in each of the central blocks 36 and 49, and an ignition plug 39 that projects into the combustion chamber 5 is attached to the plug insertion hole 38.

The timing pulley 4 is attached to one end of each of the camshafts 18i, 18e protruding from the cylinder head 3 and the head cover 14.
0, 41 are fixed, and a timing belt 42 for transmitting a driving force from a crank shaft (not shown) is wound around both timing pulleys 40, 41. As a result, both cam shafts 18i and 18e rotate in the same direction.

The low speed cams 19i and 20i are integrated on the camshaft 18i at the positions corresponding to the intake valves 10i, and the low speed cams 1
A high speed cam 21i is integrated between 9i and 20i. On the other hand, the rocker shaft 22i is located below the cam shaft 18i,
Each cam support 2 having an axis parallel to the cam shaft 18i
It is fixedly held by 7,27,28 .... The rocker shaft 22i has a first intake valve 10i that is interlocked with and connected to the first intake valve 10i.
The drive rocker arm 23i, a second drive rocker arm 24i that is interlocked and connected to the other intake valve 10i, and a free rocker arm 25i that is arranged between the first and second drive rocker arms 23i and 24i are adjacent to each other and pivot. Supported.

Tappet screws 43i are respectively screwed to the first and second drive rocker arms 23i, 24i so as to be able to move forward and backward, and these tappet screws 43i abut the upper ends of the corresponding intake valves 10i, whereby both drive rocker arms 23i, 24i. Are linked and connected to the intake valves 10i, respectively.

In addition, the free rocker arm 25i uses the lost motion mechanism 44i interposed between the free rocker arm 25i and the cylinder head 3 to drive the high-speed cam 2
It is elastically urged in the direction of sliding contact with 1i. This lost motion mechanism 44i has a bottomed cylindrical guide member 45 fitted into the cylinder head 3 with its closed end facing the cylinder head 3.
And a piston 46 slidably fitted to the guide member 45 and abutting the lower surface of the free rocker arm 25i, and a piston 4 for biasing the piston 46 toward the free rocker arm 25i.
The first and second springs 47 and 48 are provided in series between the 6 and the guide member 45, and the spring constants of the first and second springs 47 and 48 are set to be different from each other.

In FIG. 6, a hydraulic connection switching mechanism 26i includes a first switching pin 51 that can connect the first drive rocker arm 23i and the free rocker arm 25i and a second switching pin 51 that can connect the free rocker arm 25i and the second drive rocker arm 24i. Switch pin 52
And a regulating pin 53 for regulating the movement of the first and second switching pins 51, 52, and a return spring 54 for urging each of the pins 51 to 53 toward the decoupling side.

In the first drive rocker arm 23i, a bottomed first guide hole 55 opened to the free rocker arm 25i side is provided with a rocker shaft 22i.
The first switching pin 51 is slidably fitted in the first guide hole 55, and is disposed between one end of the first switching pin 51 and the closed end of the first guide hole 55. The hydraulic chamber 56 is defined. Moreover, the first drive rocker arm 23i is provided with a passage 57 communicating with the hydraulic chamber 56, the rocker shaft 22i is provided with an oil supply passage 58i, and the oil supply passage 58i is provided in the first drive rocker arm 23i.
It always communicates with the hydraulic chamber 56 via the passage 57 regardless of the rocking state of i.

A guide hole 59 corresponding to the first guide hole 55 is formed in the free rocker arm 25i so as to be parallel to the rocker shaft 22i and between both side surfaces, and one end of the first switching pin 51 abuts against the other end. The second switching pin 52 is slidably fitted in the guide hole 59.

In the second drive rocker arm 24i, a second bottomed guide hole 60 corresponding to the guide hole 59 is opened in the free rocker arm 25i side and is provided in parallel with the rocker shaft 22i.
A disc-shaped restriction pin 53 that abuts the other end of the second switching pin 52 is slidably fitted in the second guide hole 60. Moreover, a guide cylinder 61 is fitted in the closed end of the second guide hole 60, and a shaft portion 62 slidably fitted in the guide cylinder 61 is provided coaxially and integrally with the restriction pin 53 so as to project. It The return spring 54 is a guide tube.
This return spring is inserted between 61 and the regulation pin 53.
The pins 51, 52, 53 are biased toward the hydraulic chamber 56 side by 54.

In the connection switching mechanism 26i, the hydraulic pressure in the hydraulic chamber 56 increases, so that the first switching pin 51 fits into the guide hole 59 and the second switching pin 52 fits into the second guide hole 60.
Each rocker arm 23i, 25i, 24i is connected. Also hydraulic chamber 5
When the hydraulic pressure of 6 becomes low, the spring force of the return spring 54 causes the first switching pin 51 to return to the position where the contact surface between the first switching pin 51 and the second switching pin 52 is made to correspond between the first drive rocker arm 23i and the free rocker arm 25i, and the second switching is performed. Since the pin 52 returns to the position where the contact surface with the restriction pin 53 is made to correspond to between the free rocker arm 25i and the second drive rocker arm 24i, each rocker arm 23i, 25i,
The connected state of 24i is released.

Next, referring to FIG. 7, the oil supply system for the both valve operating devices 17i, 17e will be described. At the discharge port of the oil pump 64 as a hydraulic pressure supply source for pumping oil from the oil pan 63, the relief valve 65, An oil gallery 68 is connected via an oil filter 66 and an oil cooler 67.
Hydraulic pressure is supplied from 68 to each connection switching mechanism 26i, 26e, and at the same time, lubricating oil is supplied to each lubricating portion of the valve trains 17i, 17e.

The oil gallery 68 has a switching valve for switching the hydraulic pressure passing through a filter 70 provided midway between high and low to supply the oil pressure.
Oil supply passage 58i, 58e in each rocker shaft 22i, 22e via 69
Are connected.

On the top surface of each cam holder 29, 29, 30 ... Both cam shafts 18i,
Passage forming members 72i and 72e extending in parallel corresponding to 18e are fastened by a plurality of bolts 73, respectively. Moreover, each of the passage forming members 72i, 72e has a low speed lubrication passage 74 with both ends closed.
i, 74e and high-speed lubrication passages 75i, 75e communicating with the oil supply passages 58i, 58e via the throttles 76i, 76e are provided in parallel with each other.

An oil passage 77, which branches from the oil gallery 68 on the upstream side of the filter 70 and has a throttle 79 in the middle, is provided so as to extend upward in the cylinder block 1 as shown in FIG. Moreover, the oil passage 77 is provided in the cylinder block 1 near one end (close to the left end in FIG. 2) along the arrangement direction of the cylinders 2. On the other hand, a cam support portion 27 near one end along the arrangement direction of each cylinder 2 is provided with a low-speed hydraulic pressure supply passage 78 communicating with the oil passage 77, and the supply passage 78 has an annular shape surrounding the bolt 33. Of the passage portion 78a, a passage portion 78b which communicates with the upper end of the passage portion 78a and extends toward the central portion between the valve operating devices 17i, 17e, and a passage portion 78b which communicates with the passage portion 78b and extends upward and the cam support portion 27a. And a passage portion 78c opening to the upper surface of the.

Also, a cam holder at one end along the arrangement direction of each cylinder 2
The 29 is provided with a substantially Y-shaped branch oil passage 80 which is connected to the upper end of the passage portion 78c in the low speed hydraulic pressure supply passage 78 and which is distributed to both valve operating devices 17i and 17e.
The upper end of 80 is communicated with the low speed lubrication passages 74i and 74e, respectively. That is, the branch oil passage 8 is provided in the passage forming members 72i and 72e.
Communication holes 81i, 81e that connect 0 to the low speed lubrication paths 74i, 74e
Are drilled respectively.

Low speed lubrication passages 74i, 74e are for each cam 19i, 19e, 20i, 20e, 21i, 21e
With the rocker arms 23i, 23e, 24i, 24e, 25i, 25e, and the cam journal part 1 of the camshafts 18i, 18e.
It is for supplying lubricating oil to 8i 'and 18e'. Therefore, the low-speed cams 19i, 1
9e, 20i, 20e and high-speed cams 21i, 21e at the positions corresponding to the low-speed lubrication passages 74i, 74e lubricating oil injection holes 82i, 8
2e is bored in the cam holder 29, and the cam holder 29 is supplied with the low-speed lubricating oil 7h to supply the lubricating oil to the cam journal portions 18i ', 18e'.
Lubricating oil supply passages 83i and 83e communicating with 4i and 74e are bored.

The high-speed lubrication paths 75i, 75e are for supplying lubricating oil to the sliding contact portions between the high-speed cams 21i, 21e and the free rocker arms 25i, 25e, and are not provided on the lower surface of the passage forming members 72i, 72e. High-speed lubrication passages 75i, 75e at positions corresponding to high-speed cams 21i, 21e
Lubricating oil ejection holes 84i, 84e which communicate with the.

By the way, the passage forming members 72i and 72e are connected to the camshafts 18i and 18e.
Is located above the above, and each lubricating oil ejection hole 84i, 84e
A part of the lubricating oil ejected from the engine is laterally scattered according to the rotation of the camshafts 18i and 18e. Moreover, since both camshafts 18i and 18e rotate in the same direction, a part of the lubricating oil ejected from one lubricating oil ejection hole 84i is scattered to the exhaust side valve operating device 17e side, while the other A part of the lubricating oil ejected from the lubricating oil ejection hole 84e is scattered toward the side opposite to the intake side valve operating device 17i. Thus, since there are central blocks 36, 49 between the valve operating devices 17i, 17e at the portions corresponding to the lubricating oil ejection holes 84i, 84e, some of the scattered lubricating oil is at the central blocks 36, 49. It reflects and returns to the sliding contact side between the high speed cam 21i and the free rocker arm 25i. Further, a part of the lubricating oil ejected and scattered from the lubricating oil ejection hole 84e hits the side portion of the cylinder head 3 and is reflected to return to the sliding contact side between the high speed cam 21e and the free rocker arm 25e. However, the distance between the sliding contact portion between the high speed cam 21i and the free rocker arm 25i and the central blocks 36, 49 is between the sliding contact portion between the high speed cam 21e and the free rocker arm 25e and the side portion of the cylinder head 3. Less than the distance of the central block
The amount of lubricating oil reflected from 36 and 49 and returned to the sliding contact portion of the high speed cam 21i and the free rocker arm 25i is reflected from the side portion of the cylinder head 3 and returned to the sliding contact portion of the high speed cam 21e and the free rocker arm 25e. More than the amount of lubricating oil. Therefore, the diameter of the lubricating oil ejection hole 84i is set smaller than the diameter of the lubricating oil ejection hole 84e, and the amount of lubricating oil ejection from the lubricating oil ejection hole 84i is set smaller than the amount of lubricating oil ejection from the lubricating oil ejection hole 84e. To be done. Further, the degree of reduction of the throttle 76i provided between the oil supply passage 58i and the high speed lubrication passage 75i is determined by the oil supply passage 58e and the high speed lubrication passage.
It is set smaller than the throttling degree of the throttle 76e provided between the high speed lubrication passage 75i and the high speed lubrication passage 75i, so that the amount of lubricating oil supplied to the high speed lubrication passage 75i is set smaller than the amount of lubricating oil supplied to the high speed lubrication passage 75e. It

The lubricating oil jet holes 82i, 8 communicating with the low speed lubrication passages 74i, 74e
2e is a member for reflecting the lubricating oil in the direction in which the lubricating oil is scattered by the rotation of the cam shafts 18i, 18e, and a low speed cam.
Since the distances between 19i, 19e, 20i, 20e and the sliding contact portions of the first and second drive rocker arms 23i, 23e, 24i, 24e are substantially the same, the hole diameters are set to be substantially the same.

In FIG. 8, in the cylinder block 1, an oil passage 85 extending vertically at a substantially central portion along the arrangement direction of each cylinder 2 is provided.
However, it is provided independently of the oil passage 77.
85 is an oil gallery through the filter 70 (see FIG. 7)
Connect to 68. On the other hand, at a substantially central portion along the arrangement direction of each cylinder 2, the cylinder head 3 is provided with a high-speed hydraulic pressure supply passage 86 communicating with the oil passage 85, and the supply passage 86 has an annular shape surrounding the bolt 33. The passage portion 86a, the passage portion 86b which communicates with the upper end of the passage portion 86a and extends toward the center portion between the valve operating devices 17i, 17e, and the passage portion 86b which communicates with the passage portion 86b and extends upward, and also of the cam support portion 28. And a passage portion 86c that opens to the upper surface.

In addition, a cam holder at the central portion along the arrangement direction of each cylinder 2
The 30 is provided with a hydraulic pressure supply passage 87 that communicates with the upper end of the passage portion 86c in the high speed hydraulic pressure supply passage 86 and opens to the upper surface of the cam holder 30. Furthermore, this hydraulic supply path
An oil supply port 88 adjacent to 87 and opening on the upper surface of the cam holder 30 is formed in the cam holder 30. Moreover, the cam support portion 28 is provided with a substantially V-shaped branched oil passage 89 which is connected to the lower end of the oil supply port 88 at its upper end and is distributed to both valve operating devices 17i and 17e. The rocker shaft 22i, 22
through the communication holes 90i, 90e formed in the side wall of e, the oil supply passage 58i,
It is connected to 58e. Therefore, the refueling port 88 is refueling passages 58i, 58e.
Will be connected to.

The switching valve 69 is attached to the upper surface of the cam holder 30 in order to switch between communication and cutoff between the hydraulic pressure supply passage 87 and the oil supply port 88, and is connected to the inlet port 91 and the oil supply port 88 communicating with the hydraulic pressure supply passage 87. With the outlet port 92 communicating with the cam holder 30
Inside the housing 93, which is mounted on the upper surface of the
94 is slidably fitted.

The housing 93 is provided with a cylinder hole 95 having an inclined axis corresponding to the upper surface of the cover 14, and the upper end of the cylinder hole 95 is closed by a cap 96. The spool valve element 94 forms an operating hydraulic chamber 97 with the cap 96 and is slidably fitted in the cylinder hole 94.

A spring chamber 98 formed between the lower end of the cylinder hole 95 and the spool valve body 94 accommodates a spring 99 that biases the spool valve body 92 in the closing direction. The spool valve body 94 has an annular recess 10 capable of communicating between the inlet port 91 and the outlet port 92.
0 is provided and as shown in FIG.
When 4 is in a position where the hydraulic pressure chamber 97 is contracted, the spool valve element 94 is in a state of blocking the inlet port 91 and the outlet port 92.

With the housing 93 attached to the top surface of the cam holder 30,
An oil filter is installed between the inlet port 91 and the hydraulic supply line 87.
101 is sandwiched. The housing 93 also has an inlet port 9
An orifice hole 102 that communicates between 1 and the outlet port 92 is bored. Therefore, even when the spool valve body 94 is in the closed position, the inlet port 91 and the outlet port 92 are communicated with each other through the orifice hole 102, and the hydraulic pressure throttled by the orifice hole 102 is changed from the outlet port 92 to the oil supply port 88. Is supplied to.

Further, the housing 93 is provided with a bypass port 103 that communicates with the outlet port 92 via the annular recess 100 only when the spool valve body 94 is in the closed position.
Communicate with the upper part of the cylinder head 3. Housing 93
An oil passage 105, which always communicates with the inlet port 91, is bored in parallel with the cylinder hole 95, and this oil passage 105 is connected to the working hydraulic chamber 97 via an oil filter 106 and a solenoid valve 107. . Therefore, when the solenoid valve 107 is opened, the hydraulic pressure is supplied to the hydraulic pressure chamber 97, and the hydraulic pressure of the hydraulic pressure introduced into the hydraulic pressure chamber 97 drives the spool valve element 94 in the valve opening direction.

A leak jet 108 communicating with the working hydraulic chamber 97 is bored in the housing 93, and the leak jet 108 communicates with an upper portion in the cylinder head 3. The leak jet 108 serves to release the hydraulic pressure remaining in the working hydraulic chamber 97 when the solenoid valve 107 is closed.

On the other end side along the arrangement direction of each cylinder 2, a passage forming member
At the ends of 72i, 72e, communication holes (not shown) communicating with the high-speed lubrication passages 75i, 75e are opened downward, and these communication holes and the other ends of the rocker shafts 22i, 22e are formed. The communication holes 71i and 71e formed in the
It communicates via i, 76e. Therefore, the oil supplied to the oil supply passages 58i, 58e passes through the throttles 76i, 76e and the high speed lubricating oil 75i, 7
Will be supplied to 5e.

Explaining the operation of this embodiment, the low speed lubrication passages 74i, 74e are provided with an oil passage 77, a low speed hydraulic pressure supply passage 78 and a branch oil passage 80 which are independent of the connection switching mechanisms 26i, 26e. Since the lubricating oil is supplied, even if the hydraulic pressure is controlled by the switching valve 69 to operate the connection switching mechanisms 26i, 26e, a constant hydraulic pressure can always be supplied regardless of that, and therefore the low speed cam 19i , 19e, 20i, 20e and each drive rocker arm 23
i, 23e, 24i, 24e sliding contact, high-speed cams 21i, 21e and free rocker arms 25i, 25e sliding contact, and camshaft 1
Lubricating oil can be supplied to the cam journal portions 18i ', 18e' of 8i, 18e at a stable pressure.

The switching valve 69 is opened when the connection switching mechanisms 26i and 26e are switched to bring the intake valves 10i and the exhaust valves 10e into the high-speed operation mode. That is, by opening the solenoid valve 107 and supplying hydraulic pressure to the operating hydraulic chamber 97, the spool valve element 94 is opened, hydraulic pressure is supplied to the oil supply passages 58i and 58e, and hydraulic pressure is supplied to the hydraulic chamber 56. As a result, the connection switching mechanisms 26i and 26e are connected and the intake valve 10i and the exhaust valve 10 are opened and closed in a high-speed operation mode.

Moreover, when the hydraulic pressure supply switching to the oil supply passages 58i, 58e is performed in this manner, the hydraulic oil is supplied to the substantially central portion along the axial direction of the oil supply passages 58i, 58e via the switching valve 69, so that each connection switching is performed. The difference in the time required to supply the hydraulic pressure to the mechanisms 26i, 26e is reduced, and therefore, the hydraulic connection switching mechanisms 26i, 26 arranged at the axially spaced positions of the oil supply passages 58i, 58e.
It is possible to avoid the occurrence of a shift in the timing of hydraulic pressure on e as much as possible, and it is possible to substantially match the operation change timings of the intake valve 10i and the exhaust valve 10e in each cylinder 2.

By the way, in the high-speed operation mode state, the high-speed lubrication passage 75i,
Lubricating oil supplied to 75e is ejected from the lubricating oil ejection holes 84i, 84e, and it is possible to sufficiently lubricate the sliding contact portion between the high speed cams 21i, 21e and the free rocker arms 25i, 25e where the surface pressure becomes particularly large. it can. In addition, the member for reflecting the lubricating oil scattered according to the rotation of the camshafts 18i, 18e and the high-speed cam 21
i, 21e and the free rocker arms 25i, 25e are set with the diameters of the lubricating oil jet holes 84i, 84e according to the distances between the sliding contact parts, and the throttles of the throttles 76i, 76e are set. It is possible to make the amount of lubricating oil supplied to the contact portion substantially equal.

Further, when the switching valve 69 is switched to switch from the low speed operating mode to the high speed operating mode, there is a slight time lag until the hydraulic pressure in the high speed lubricating passages 75i, 75e increases due to the throttles 76i, 76e, and the lubricating oil jet There is some time delay before the lubricating oil is ejected from the holes 84i and 84e. However, the lubricating oil jet holes 82i, 82e leading to the low speed lubrication passages 74i, 74e are provided with high speed cams.
Since it is also arranged at the position corresponding to the sliding contact portion between the 21i, 21e and the free rocker arm 25i, 25e, even if there is some time delay as described above, the high speed cams 21i, 21e and the free rocker arm 25i There is no shortage of lubricating oil at the sliding contact parts of 25e. In addition, each pin 51, 52, 53 in the connection switching mechanism 26i, 26e
When the state in which the switching valve 69 is closed and the low-speed operation mode is generated while the lock is maintained, the surface pressure of the sliding contact portions of the high-speed cams 21i and 21e and the free rocker arms 25i and 25e is the same as in the high-speed operation mode. However, even at this time, the low speed lubrication path 74
From the lubricating oil ejection holes 82i, 82e leading to the i, 74e to the high speed cam 21i,
Lubricating oil is jetted to the sliding contact portions of the 21e and the free rocker arms 25i, 25e, so that sufficient lubrication can be performed.

When switching the opening / closing operation mode of the intake valve 10i and the exhaust valve 10e from the high speed operation mode to the low speed operation mode, the solenoid valve 107 is closed. When the solenoid valve 107 is closed,
The hydraulic pressure in the operating hydraulic chamber 97 is released from the leak jet 108, the hydraulic pressure in the operating hydraulic chamber 97 is promptly released, and the switching valve 69 is promptly closed accordingly. Moreover, when the switching valve 69 is closed, the hydraulic pressure in the oil supply passages 58i, 58e is released into the cylinder head 3 by the bypass port 103.
The hydraulic pressure of the hydraulic chambers 56 in the oil supply passages 58i, 58e, that is, the connection switching mechanisms 26i, 26e quickly becomes low, and the switching response from the high speed operation mode to the low speed operation mode is improved.

In such an oil supply device, one low speed hydraulic supply passage 78 and one high speed hydraulic supply passage 86 may be provided in each cylinder head 3, so that the cylinder head 3 is extremely easily processed. Moreover, since the switching valve 69 is mounted on the upper surface of the cam holder 30, the mounting structure is simple. Further, the oil supply passages 58i and 58e are connected to the connection switching mechanisms 26i and 26e with oil,
In addition, since it is also used for refueling the high speed lubrication oil passages 75i, 75e, it is possible to separately provide a refueling pipe passage,
It is not necessary to separately provide an oil supply passage, and it is possible to efficiently supply oil while avoiding an increase in the number of parts and an increase in processing man-hours.

C. Effect of the Invention As described above, according to the present invention, the cam holder at the substantially central portion along the arrangement direction of each cylinder has a hydraulic supply passage communicating with the hydraulic supply source and a substantially parallel oil supply passage along the axial direction. An oil supply port communicating with the central portion is provided on the upper surface of the cam holder, and a switching valve capable of switching communication and cutoff between the hydraulic pressure supply passage and the oil supply port is attached to the upper surface of the cam holder. It is possible to avoid the occurrence of a deviation in the hydraulic pressure supply to the valve operation changing means and the hydraulic pressure release timing as much as possible, and to make the operation change timing of each engine valve substantially the same.

[Brief description of drawings]

1 shows an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of an essential part of an internal combustion engine, which is a sectional view taken along line II of FIG.
1 is a partially cutaway plan view taken along line II-II in FIG. 1, FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG. Fig. 6 is a sectional view taken along line VV in Fig. 2, Fig. 6 is a lateral sectional view showing the connection switching mechanism, Fig. 7 is a diagram showing a refueling system, and Fig. 8 is a sectional view taken along line VIII-VIII in Fig. 2. Is. 1 ... Cylinder block, 2 ... Cylinder, 3 ... Cylinder head, 10i ... Intake valve as engine valve, 10e ... Exhaust valve as engine valve, 17i, 17e ... Valve operating device, 18i, 18e ...
… Camshaft, 19i, 19e, 20i, 20e, 21i, 21e …… Cam, 2
2i, 22e …… Rocker shaft, 23i, 23e, 24i, 24e, 25i, 25e
...... Rocker arm, 26i, 26e ...... Hydraulic connection switching mechanism as hydraulic valve operation changing means, 29,30 ...... Cam holder, 5
8i, 58e ... Oil supply passage, 64 ... Oil pump as hydraulic pressure supply source, 69 ... Switching valve, 87 ... Hydraulic supply passage, 88 ... Oil supply port

Claims (1)

[Scope of utility model registration request] 1. A plurality of cylinders are arranged in series in a cylinder block, and a cam shaft rotatably supported by a cylinder head and a cam holder fastened to the cylinder head is provided with a cam corresponding to each cylinder. A plurality of rocker arms fixed to the cylinder head and fixedly supported by the cylinder head are supported by a plurality of rocker arms corresponding to the rotations of the cams, corresponding to the engine valves of the cylinders. Hydraulic valve operation changing means that can be changed according to oil pressure are provided at intervals in the arrangement direction of each cylinder, and oil supply passages extending along the arrangement direction of each cylinder are respectively communicated with each hydraulic valve operation changing means. In a valve operating system for a multi-cylinder internal combustion engine, a cam holder at a substantially central portion along an arrangement direction of each cylinder has a hydraulic supply passage communicating with a hydraulic supply source and an axial direction. Opened provided the filler opening and the cam holder upper surface which communicates with the substantially central portion of the oil supply passage along,
A valve operating system for a multi-cylinder internal combustion engine, wherein a switching valve capable of switching communication and cutoff between the hydraulic pressure supply passage and the oil supply port is mounted on an upper surface of the cam holder.