JP2019173745A - Oil passage structure of internal combustion engine - Google Patents

Abstract

To provide an inexpensive oil passage structure of an internal combustion engine, capable of reducing the number of components, reducing the man-hours for assembly and improving productivity.SOLUTION: In an oil passage structure of an internal combustion engine, a cylinder head (3U) comprises a bearing wall communication oil passage (c7) allowing oil to flow between a plurality of bearing walls (3v, 3vl, 3vr), and a bearing wall oil passage (c8) branched from the bearing wall communication oil passage (c7) and supplying oil to a bearing surface (3vf) of the bearing wall (3vl). The bearing wall communication oil passage (c7) is formed on one side wall (3U) of an opposite side wall (3U, 3U), and the bearing wall oil passage (c8) is formed in the bearing wall (3vl).SELECTED DRAWING: Figure 19

Description

  The present invention relates to an oil passage structure of an internal combustion engine in which an oil passage for supplying oil to a bearing surface of a bearing wall that supports a camshaft of a cylinder head is formed.

  In an internal combustion engine in which a cylinder block and a cylinder head are stacked obliquely upward on a crankcase and fastened together and tilted together to form an engine body, the camshaft is usually composed of a cylinder head (or cylinder block) and a camshaft holder. It is pivotally supported so as to be pinched.

  And there is an example (for example, patent documents 1) in which the oil passage which supplies oil to the bearing wall which bearings the journal part of a camshaft, and the bearing surface of a camshaft holder is on the camshaft holder side.

Japanese Utility Model Publication No. 62-49604

  In the internal combustion engine disclosed in Patent Document 1, a camshaft is rotatably supported by being sandwiched between a cylinder block and a bearing cap (camshaft holder) in a cylinder head.

  The bearing cap pivotally supports the rocker arm shaft, and oil is supplied to the bearing surface of the bearing cap from the oil passage provided in the shaft center of the rocker arm shaft through the oil supply passage of the bearing cap. .

When an oil passage formed in a separate member such as a bearing cap attached to a cylinder head (or a cylinder block) is used to supply oil to the bearing of the camshaft as in Patent Document 1, the oil passage is combined. Sealability is required to prevent oil leakage from the part.
Therefore, the number of parts increases, the number of assembling steps increases, the productivity decreases, and the cost increases.

  The present invention has been made in view of the above points, and the object of the present invention is to provide an oil passage structure for an internal combustion engine that can reduce the number of parts, reduce the number of assembly steps, and improve the productivity at low cost. It is in.

In order to achieve the above object, an oil passage structure of an internal combustion engine according to the present invention includes:
An engine body is formed by overlapping a cylinder head on a cylinder block provided upward from a crankcase and fastened integrally with the cylinder block. Valves are operated on at least two bearing walls installed between opposing side walls of the cylinder head. In an oil passage structure of an internal combustion engine in which a camshaft of a device is rotatably supported, and an oil passage for supplying oil to a bearing surface of the bearing wall of the cylinder head is provided in the engine body.
The cylinder head communicates between a plurality of the bearing walls and flows oil between the bearing walls, and a bearing wall branches from the bearing wall communicating oil path and supplies oil to the bearing surface of the bearing wall. An oil passage,
The bearing wall communication oil passage is formed on one side wall of the opposed side walls,
The bearing wall oil passage is formed in the bearing wall.

  According to this configuration, in the internal combustion engine in which the camshaft of the valve gear is rotatably supported by at least two bearing walls provided between the opposing side walls of the cylinder head, the plurality of bearing walls communicate with each other. A bearing wall oil passage for flowing oil is formed on one side wall of the opposing side walls, and a bearing wall oil passage is branched from the bearing wall communication oil passage and supplies oil to the bearing surface of the bearing wall. Since it is formed integrally with the bearing wall, there is no oil leakage, the number of parts can be reduced, the number of assembly steps can be reduced, the productivity can be improved, and the cost is low.

In a preferred embodiment of the present invention,
The bearing wall communication oil passage is disposed below the bearing surface of the bearing wall.

  According to this configuration, the communication oil passage between the bearing walls is disposed below the bearing surface of the bearing wall. Therefore, even if air is mixed into the oil, the air easily escapes to the bearing surface.

In a preferred embodiment of the present invention,
One side wall where the bearing wall communication oil passage is formed is a side wall opposite to the side wall from which the exhaust pipe extends.

  According to this configuration, the one side wall in which the communication oil passage between the bearing walls is formed is the side wall opposite to the side wall from which the exhaust pipe extends, and therefore the side opposite to the side wall from which the exhaust pipe extends to increase the temperature. By forming the communication oil passage between the bearing walls on the side wall, the oil can be prevented from being heated.

In a preferred embodiment of the present invention,
In the valve operating apparatus, two parallel camshafts are rotatably supported on at least two bearing walls,
A connecting oil passage pipe is constructed from one side wall where the bearing wall communication oil passage is formed to the other side wall, and is integrally formed on both side walls,
A connecting oil passage branched from the communication oil passage between the bearing walls is formed in the connecting oil passage pipe,
A side wall oil passage extending from the connection oil passage to the bearing wall is formed on the other side wall,
The bearing wall oil passage is used as a first bearing wall oil passage, and a second bearing wall oil passage for supplying oil from the side wall oil passage to the bearing surface on the other side wall of the bearing wall is formed in the bearing wall. The

  According to this configuration, since the connecting oil passage, the side wall oil passage, and the second bearing wall oil passage are all formed integrally with the cylinder head, the number of parts can be reduced, the number of assembly steps can be reduced, and the productivity can be improved. Can be made.

In a preferred embodiment of the present invention,
The valve gear is
A camshaft oriented in the left-right vehicle width direction provided rotatably on the cylinder head;
A cam carrier that is a cylindrical member that is fitted to the outer periphery of the camshaft so as to be prohibited from relative rotation and slidable in the axial direction, and has a plurality of cam lobes with different cam profiles formed on the outer peripheral surface adjacent to each other in the axial direction. When,
A cam switching mechanism that moves the cam carrier in the axial direction and switches a cam lobe that operates on a valve;
The connecting oil passage pipe is below a cylindrical portion adjacent to the cam lobe of the cam carrier.

  According to this configuration, the valve gear is a variable valve gear including a camshaft, a cam carrier having a plurality of cam lobes with different cam profiles, and a cam switching mechanism. Since it is below the cylindrical portion adjacent to the cam lobe, the connecting oil passage pipe can be formed close to the cam carrier, and the internal combustion engine can be reduced in size by effectively using the space.

In a preferred embodiment of the present invention,
The cylinder head is composed of an upper cylinder head and a lower cylinder head which are divided into two parts in the vertical direction,
The upper cylinder head has the bearing wall that rotatably supports two parallel camshafts,
The bearing walls communicate with each other on the mating surfaces of the upper cylinder head and the lower cylinder head on the other side wall opposite to the one side wall where the communication passage between the bearing walls is formed. A groove that forms a second oil passage between the bearing walls through which oil flows is formed,
A second bearing wall oil passage is formed in the bearing wall of the upper cylinder head to branch from the second bearing wall communication oil passage and supply oil to the second bearing surface of the bearing wall.

  According to this configuration, oil is respectively supplied to the bearing surface (first bearing surface) and the second bearing surface of the bearing wall of the upper cylinder head that rotatably supports the two cam shafts in parallel. However, on the first bearing surface, the bearing wall communication oil passage (first bearing wall communication oil passage) formed on one side wall and the bearing wall oil passage (first bearing wall oil passage) are formed. ), And the second bearing surface is supplied with the second bearing wall communication oil passage formed on the other side wall and the oil flowing through the second bearing wall oil passage. As a result, oil can be efficiently and evenly supplied to the first and second bearing surfaces of each of the plurality of bearing walls for lubrication.

  On the mating surfaces of the upper cylinder head and the lower cylinder head which are divided into two parts in the upper and lower parts of the cylinder head, a second oil passage between the bearing walls is configured to communicate between the plurality of bearing walls and flow oil. Since the grooves are respectively formed, the grooves constituting the second oil passage between the bearing walls can be formed at the stage of casting for casting the upper cylinder head and the lower cylinder head. Easy to form.

  The present invention relates to an internal combustion engine in which a camshaft of a valve gear is rotatably supported on at least two bearing walls installed between opposing side walls of a cylinder head, and an oil is communicated between the plurality of bearing walls. A bearing wall oil passage is formed on one side wall of the opposing side walls, and the bearing wall oil passage branches off from the bearing wall communication oil passage and supplies oil to the bearing surface of the bearing wall. Since it is formed on the wall, there are no places to watch out for oil leakage, the number of parts can be reduced, the number of assembly steps can be reduced, the productivity can be improved, and the cost is low.

1 is an overall side view of a motorcycle on which a power unit including an oil passage structure for an internal combustion engine according to an embodiment of the present invention is mounted. It is a left view of the power unit. It is a perspective view of the power unit. It is the left view which showed the outline of the cylinder head of the internal combustion engine etc. with the dashed-two dotted line, and showed the principal part of the internal valve operating apparatus through. It is the top view which removed the cylinder head cover and the camshaft holder, and looked at the upper cylinder head from the top. FIG. 4 is a perspective view showing only main parts with a part of an intake side cam switching mechanism and an exhaust side cam switching mechanism omitted. It is the perspective view which assembled | attached the 1st switching pin and the 2nd switching pin to the intake side switching drive shaft. It is explanatory drawing which shows the pressure oil supply / discharge state to the intake side hydraulic actuator and the exhaust side hydraulic actuator when the linear solenoid valve is not excited. It is explanatory drawing which shows the pressure oil supply / discharge state to the intake side hydraulic actuator and the exhaust side hydraulic actuator when the linear solenoid valve is excited. It is a front view which shows the left end mating surface of the front surface of the front side wall of an upper cylinder head. It is a perspective view of a linear solenoid valve. It is explanatory drawing which shows the operation state of the main member of the intake side cam switching mechanism at the time of low speed driving | operation of an internal combustion engine. It is explanatory drawing which shows the operation state of the main member of the intake side cam switching mechanism at the time of high speed driving | operation of an internal combustion engine. It is a front view of an internal combustion engine. It is a disassembled front view of the engine main body of an internal combustion engine. It is a top view of the upper crankcase of the internal combustion engine. It is a top view of the cylinder block of the internal combustion engine. It is a top view of the lower cylinder head of the internal combustion engine. It is a top view of the upper cylinder head of the internal combustion engine. It is a bottom view of the upper cylinder head. It is the perspective view which showed only the flow path of the oil in the left side wall of the same upper side cylinder head. It is the left view which showed only the flow path of the oil. It is the top view which showed only the flow path of the oil. It is the left view which showed the front part of the engine body of an internal-combustion engine in the section. FIG. 20 is a cross-sectional view of the upper cylinder head taken along the line XXV-XXV in FIG. 19. It is sectional drawing of the upper side cylinder head of the XXVI-XXVI arrow of FIG. FIG. 20 is a cross-sectional view of the upper cylinder head taken along the line XXVII-XXVII in FIG. 19. FIG. 20 is a cross-sectional view of the upper cylinder head taken along the line XXVIII-XXVIII in FIG. 19. FIG. 20 is a cross-sectional view of the upper cylinder head as viewed in the direction of arrows XXIX-XXIX in FIG. 19. It is a left view of a cam shaft holder. It is a bottom view of the camshaft holder. It is a top view of the lower cylinder head of the internal combustion engine provided with the oil passage structure concerning another embodiment of the present invention. It is a top view of the upper cylinder head of the internal combustion engine. It is a bottom view of the upper cylinder head. FIG. 35 is a cross-sectional view of an assembly of a cylinder block, a lower cylinder head, and an upper cylinder head as viewed in the direction of arrows XXXV-XXXV in FIGS. 32 to 34.

An embodiment according to the present invention will be described below with reference to FIGS.
FIG. 1 is a side view of a motorcycle 100 that is a straddle-type vehicle equipped with an internal combustion engine according to an embodiment to which the present invention is applied.
In the present specification and claims, the front-rear and left-right orientations conform to the normal standard in which the straight direction of the motorcycle 100 according to the present embodiment is the forward direction. Indicates the rear, LH indicates the left side, and RH indicates the right side.

The body frame of the motorcycle 100 extends from a head pipe 102 that supports a front fork 105 that pivotally supports a front wheel 106 so that the front fork 105 can be steered, and a pair of left and right main frames 103 branch from left to right.
An engine hanger portion 103a hangs downward from the front portion of the main frame 103, a rear portion of the main frame 103 is bent, and a pivot frame portion 103b extends downward.
A seat rail 104 is connected to the rear of the center of the main frame 103 and extends rearward.

A swing arm 108 whose front end is pivotally supported by a pivot shaft 107 on the pivot frame 103b extends rearward, and a rear wheel 109 is pivotally supported on the rear end of the swing arm 108.
A link mechanism 110 is provided between the swing arm 108 and the pivot frame portion 103b, and a rear cushion 111 is interposed between a part of the link mechanism 110 and the seat rail 104.

  A power unit Pu is suspended between the engine hanger portion 103a and the pivot frame portion 103b of the main frame 103, and the vehicle body frame is fitted to an output shaft that is a counter shaft 12 of the transmission M of the power unit Pu. A travel drive chain 114 is suspended between the drive sprocket 112 and a travel driven sprocket 113 fitted to the rear axle of the rear wheel 109.

  The main frame 103 is provided with an air cleaner 122 in the first half and a fuel tank 116 in the second half. A main seat 117 and a pillion seat 118 are supported by the seat rail 104 at the rear of the fuel tank 116.

The internal combustion engine E that occupies the first half of the power unit Pu is an in-line four-cylinder, water-cooled, four-stroke internal combustion engine that is horizontally mounted on the crankshaft, and is mounted on the vehicle body frame with the cylinder tilted appropriately forward.
A crankshaft 10 of the internal combustion engine E is axially supported by the crankcase 1 in the vehicle body width direction (left-right direction), and the crankcase 1 is integrally provided with a transmission M behind the crankshaft 10.

  Referring to FIG. 2, the internal combustion engine E includes a cylinder block 2 in which four cylinders separate from the crankcase 1 are arranged in series on the crankcase 1, and a gasket on the top of the cylinder block 2. And an engine body Eh composed of a cylinder head 3 coupled via the cylinder head 3 and a cylinder head cover 4 placed on top of the cylinder head 3.

The cylinder axis Lc that is the center axis of the cylinder of the cylinder block 2 is inclined forward, and the cylinder block 2, the cylinder head 3, and the cylinder head cover 4 stacked on the crankcase 1 are slightly inclined forward from the crankcase 1. It extends upward in posture.
An oil pan 5 bulges downward from the crankcase 1.

The crankcase 1 is divided into upper and lower parts, and a crankshaft 10 is pivotally supported between the upper and lower crankcases 1U and 1L.
The crankcase 1 incorporates a transmission M behind the crankshaft 10, and the mainshaft 11 and the countershaft 12 constituting the transmission M are oriented in the vehicle body width direction in parallel with the crankshaft 10. 1 (see FIG. 2).

  In the transmission chamber of the crankcase 1, a main shaft 11 and a countershaft 12 of the transmission M are arranged in parallel to the crankshaft 10 so as to be oriented in the horizontal direction (see FIG. 3). Passes through the crankcase 1 to the left and protrudes outward to form an output shaft.

An intake pipe extending for each cylinder is connected to the air cleaner 122 on the rear side surface of the cylinder head 3 via the throttle body 121 (see FIG. 1).
Further, an exhaust pipe 125 extends from the front side surface of the cylinder head 3 for each cylinder, and each exhaust pipe 125 extends downward and bends backward to extend the right side of the oil pan 5 backward.

The internal combustion engine E includes a variable valve operating device 40 having a DOHC structure in a four-valve system in the cylinder head 3.
The cylinder head 3 of the internal combustion engine E is vertically divided into two in the cylinder axis direction (the axis direction of the cylinder axis Lc), and a lower cylinder head 3L and a lower cylinder head 3L that are stacked on the cylinder block 2. The upper cylinder head 3U is overlaid on the upper side (see FIGS. 2 and 4).

Referring to FIG. 4, in the lower cylinder head 3L, for each cylinder, two intake ports 31i curve backward and extend obliquely upward from the combustion chamber 30, and two exhaust ports 31e curve forward. Is extended.
In the lower cylinder head 3L, an intake valve 41 and an exhaust valve 51 for opening and closing an intake opening to the combustion chamber 30 of the intake port 31i and an exhaust opening to the combustion chamber 30 of the exhaust port 31e are provided for rotation of the crankshaft 10, respectively. It is supported so as to be reciprocally slidable synchronously.

The lower cylinder head 3L is fastened together with the cylinder block 2 to the upper crankcase 1U by a stud bolt 7 (see FIGS. 4 and 5).
The upper cylinder head 3U overlaid on the lower cylinder head 3L has a long front wall 3U _F and a rear wall 3U _B which are long in the front and rear and a short length in the front and rear. left side wall 3U _L, the four sidewalls of the right side wall 3U _R a rectangular frame walls.

Rectangular frame of the upper cylinder head 3U is partitioned into right narrow cam chain chamber 3c and the left valve chamber 3d by a bearing wall 3vr formed in parallel along the right side wall 3U _R, the valve operating chamber 3d is It is partitioned into five chambers by the four bearing wall 3v parallel to more left and right side walls _3U L, _{3U R.}
Each bearing wall 3v is located above the center of the combustion chamber 30 of each cylinder, and is formed with a plug fitting cylinder portion 3vp into which a spark plug is fitted in the center in the front-rear direction.

The variable valve operating device 40 is provided in a valve operating chamber 3 d formed by the cylinder head 3 and the cylinder head cover 4.
Referring to FIGS. 4 and 5, a pair of left and right intake valves 41, 41 provided in each cylinder of the in-line four cylinders are arranged in series in the left-right direction, and the four pairs of intake valves 41, 41 are arranged in series. A single intake side camshaft 42 is disposed on the upper side in the left-right direction, and is fitted to a bearing surface 3vf that forms a semicircular arc surface of the bearing walls 3v, 3vr of the upper cylinder head 3U. It is pivotally supported so as to be sandwiched.

Similarly, four pairs of left and right exhaust valves 51, 51 provided in series in the left-right direction of each cylinder are arranged in series in the left-right direction, and one exhaust is disposed above the four pairs of exhaust valves 51, 51. The side camshaft 52 is disposed in the left-right direction and is rotatably supported so as to be sandwiched by the camshaft holder 33 between the bearing walls 3v, 3vr, 3vl of the upper cylinder head 3U.
The exhaust camshaft 52 is disposed in front of the intake camshaft 42 in parallel.

Referring to FIG. 5, the intake camshaft 42 has a journal part (bearing part) 42a that is pivotally supported by the bearing wall 3vr near the right end, and the bearing wall 3vr is formed by flanges on both sides of the bearing part 42a. The spline shaft portion 42b having spline external teeth formed on the outer peripheral surface extends through the four bearing walls 3v of the valve operating chamber 3d on the left side of the bearing portion 42a. I'm out.
An intake side driven gear 47 is fitted on the right end flange of the intake side camshaft 42 protruding into the cam chain chamber 3c.

Similarly, the exhaust-side camshaft 52 has a journal part (bearing part) 52a that is pivotally supported by the bearing wall 3vr in the vicinity of the right end, and axially sandwiches the bearing wall 3vr by flanges on both sides of the bearing part 52a. The spline shaft portion 52b extends through the four bearing walls 3v of the valve operating chamber 3d on the outer peripheral surface on the left side of the bearing portion 52a.
An exhaust-side driven gear 57 is fitted to the right end flange of the exhaust-side camshaft 52 protruding into the cam chain chamber 3c.

On the spline shaft portion 42b of the intake camshaft 42, four intake cam carriers 43, which are cylindrical members, are arranged by spline fitting.
The four intake side cam carriers 43 are prohibited from relative rotation with respect to the intake side camshaft 42 and are slidably fitted in the axial direction.
Similarly, four exhaust-side cam carriers 53, which are cylindrical members, are spline-fitted and arranged on the spline shaft portion 52b of the exhaust-side camshaft 52, and the four exhaust-side cam carriers 53 are respectively connected to the exhaust side. Relative rotation with respect to the camshaft 52 is prohibited, and the camshaft 52 is slidably fitted in the axial direction.

FIG. 6 is a perspective view showing only main parts with a part of the intake side cam switching mechanism and the exhaust side cam switching mechanism omitted.
Referring to FIG. 6 (and FIG. 5), each intake side cam carrier 43 has a pair of a high speed side cam lobe 43A having a large lift amount and a low speed side cam lob 43B having a small lift amount on the outer peripheral surface in the axial direction. A pair adjacent to the left and right is formed on the left and right, respectively, with a supported cylindrical portion 43C having a predetermined width in the axial direction.
The adjacent high speed side cam lobe 43A and low speed side cam lobe 43B have the same outer diameter of the basic circle of the cam profile and are at the same circumferential position (see FIGS. 4 and 5).

Each intake side cam carrier 43 has a lead groove cylindrical portion 43D formed so that a lead groove 44 circulates on the right side of the right side high speed cam lobe 43A in the right side high speed cam lobe 43A and low speed side cam lobe 43B. Have.
The outer diameter of the lead groove cylindrical portion 43D is slightly smaller than the outer diameter of the base circle of the same diameter of the high speed side cam lobe 43A and the low speed side cam lobe 43B.

  The lead groove 44 of the lead groove cylindrical portion 43D is formed with an annular lead groove 44c that circulates in the circumferential direction in an annular shape at a predetermined position in the axial direction, and branches from the annular lead groove 44c to the left and right to a predetermined distance in the axial direction left and right A right shift lead groove 44r and a left shift lead groove 44l are formed spirally to a distant position (see FIG. 5).

Four intake side cam carriers 43 are sequentially spline-fitted to the spline shaft portion 42b of the intake side camshaft 42 and arranged on the intake side camshaft 42 with a predetermined interval.
As shown in FIG. 5, the intake-side camshaft 42 in which the four intake-side cam carriers 43 are arranged in this way is the bearing surface 3vr of the upper cylinder head 3U and the respective bearing surfaces on the rear side of the four bearing walls 3v. It is supported by 3vf.
The bearing portion 42a of the intake side camshaft 42 is supported by the bearing wall 3vr, and the supported cylindrical portion 43C of each intake side cam carrier 43 is supported by each bearing wall 3v.

On the other hand, the exhaust-side cam carrier 53 that is spline-fitted to the spline shaft portion 52b of the exhaust-side camshaft 52, like the intake-side cam carrier 43, has a pair of high-speed cam lobes 53A and low-speed cam lobes with different cam profiles on the outer peripheral surface. A pair of 53B adjacent to the left and right in the axial direction is formed on the left and right, respectively, with a cylindrical portion 53C having a predetermined width in the axial direction, and a pair of a high speed side cam lobe 53A and a low speed side cam lobe 53B. A lead groove cylindrical portion 53D is formed on the right side of the right side high-speed cam lobe 53A.
The lead groove 54 formed in the lead groove cylindrical portion 53D is branched to the left and right from the annular lead groove 54c that makes a round in the circumferential direction, and spirally shifts to the left shift lead groove 54r and the left shift to a position separated by a predetermined distance in the left and right directions in the axial direction. A lead groove 54l is formed (see FIG. 5).

As shown in FIG. 5, the exhaust side camshaft 52 in which four exhaust side cam carriers 53 are sequentially spline-fitted to the spline shaft portion 52b constitutes the front side of the bearing wall 3vr and the four bearing walls 3v of the upper cylinder head 3U. Are supported by the bearing surfaces 3vf.
A bearing portion 52a of the exhaust side camshaft 52 is supported by the bearing wall 3vr, and a bearing cylindrical portion 53C of each exhaust side cam carrier 53 is supported by each bearing wall 3v.

  As described above, the intake side camshaft 42 (and the intake side cam carrier 43) and the exhaust side camshaft 52 (and the exhaust side cam carrier 53) are provided on the bearing wall 3vr and the four bearing walls 3v of the upper cylinder head 3U. When supported, the intake side camshaft 42 (and the intake side cam carrier 43) and the exhaust side camshaft 52 are placed on the bearing wall 3vr and the four bearing walls 3v by camshaft holders 33 (see FIG. 4). (And the exhaust side cam carrier 53) are sandwiched and rotatably supported.

  That is, the four intake-side cam carriers 43 are supported so as to be slidable in the axial direction while rotating together with the intake-side camshaft 42, and the four exhaust-side cam carriers 53 are also rotated while being rotated together with the exhaust-side camshaft 52. It is pivotally supported so as to be slidable in the direction.

  The intake-side driven gear 47 attached to the right end of the intake-side camshaft 42 and the exhaust-side driven gear 57 attached to the right end of the exhaust-side camshaft 52 have the same diameter and are lined up in the cam chain chamber 3c in the rear and front. As shown in FIG. 4, a large-diameter idle gear 61 that meshes with both the intake-side driven gear 47 and the exhaust-side driven gear 57 is pivotally supported downwardly between the two. Has been.

  Referring to FIGS. 4 and 5, idle chain sprocket 62 having the same central axis is rotatably provided integrally with idle gear 61, and cam chain 66 is wound around idle chain sprocket 62. On the other hand, it is wound around a small-diameter drive chain sprocket (not shown) fitted to the lower crankshaft 10.

  Therefore, the rotation of the crankshaft 10 is transmitted to the idle chain sprocket 62 via the cam chain 66, and the rotation of the idle gear 61 integral with the idle chain sprocket 62 meshes with the idle gear 61 and the exhaust side driven gear 47 and the exhaust. Since the side driven gear 57 is rotated, the intake side driven gear 47 rotates the intake side camshaft 42 integrally, and the exhaust side driven gear 57 rotates the exhaust side camshaft 52 integrally.

  Referring to FIG. 6, an intake side switching drive shaft 71 of the intake side cam switching mechanism 70 is disposed in parallel with the intake side camshaft 42 at an obliquely lower front side of the intake side camshaft 42, and an exhaust side camshaft 52. The exhaust-side switching drive shaft 81 of the exhaust-side cam switching mechanism 80 is disposed in parallel with the exhaust-side camshaft 52 at an obliquely lower front side.

The intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 are supported by the upper cylinder head 3U.
Referring to FIGS. 5, 6 and 12, the upper cylinder head 3 </ b> U has a cylindrical portion 3 </ b> A oriented in the left-right direction toward the valve operating chamber 3 d, and has four bearing walls 3 vr positioned slightly rearward from the center. It is formed in a straight line through the bearing wall 3v.

Similarly, the upper cylinder head 3U, cylindrical portion 3B which is directed in the lateral direction valve chamber 3d is formed in a straight line on the inner surface of the front wall 3U _F from the bearing wall 3vr through the four bearing wall 3v (See FIG. 5).
The intake-side switching drive shaft 71 is inserted into the axial hole of the cylindrical portion 3A so as to be slidable in the axial direction, and the exhaust-side switching drive shaft 81 is inserted into the axial hole of the cylindrical portion 3B so as to be slidable in the axial direction. It is.

Two positions corresponding to the left and right intake valves 41, 41 are missing at both sides of the cylindrical portion 3A across the bearing wall 3v, and the intake side switching drive shaft 71 is exposed. This intake side switching drive shaft Intake rocker arms 72 and 72 are pivotally supported on the exposed portion of 71 (see FIGS. 5 and 12).
That is, the intake side switching drive shaft 71 also serves as a rocker arm shaft.

4 and 6, the tip end portion of the intake rocker arm 72 abuts on the upper end portion of the intake valve 41, and the curved upper end surface of the intake rocker arm 72 is fastened by the axial movement of the intake side cam carrier 43. Either the side cam lobe 43A or the low speed side cam lobe 43B is in sliding contact.
Therefore, when the intake side cam carrier 43 rotates, either the high speed side cam lobe 43A or the low speed side cam lobe 43B swings the intake rocker arm 72 in accordance with the profile, and presses the intake valve 41 to inject the intake valve port of the combustion chamber 30. open.

Similarly, two positions corresponding to the left and right exhaust valves 51, 51 are missing at both side positions of the cylindrical portion 3B across the bearing wall 3V, and the exhaust side switching drive shaft 81 is exposed. An exhaust rocker arm 82 is pivotally supported on the exposed portion of the switching drive shaft 81 (see FIGS. 5 and 6).
That is, the exhaust side switching drive shaft 81 also serves as a rocker arm shaft.

4 and 6, the distal end portion of exhaust rocker arm 82 abuts on the upper end portion of exhaust valve 51, and the upper end surface of exhaust rocker arm 82 is curved to the high speed side cam lobe 53A by the movement of exhaust side cam carrier 53. Alternatively, one of the low-speed cam lobes 53B comes into sliding contact.
Therefore, when the exhaust side cam carrier 53 rotates, either the high speed side cam lobe 53A or the low speed side cam lobe 53B swings the exhaust rocker arm 82 according to the profile, and presses the exhaust valve 51 to exhaust the exhaust valve port of the combustion chamber 30. open.

Referring to FIG. 12, two cylindrical boss portions 3As and 3As are adjacent to the left and right sides of the cylindrical portion 3A corresponding to the lead groove cylindrical portion 43D of the intake side cam carrier 43 toward the lead groove cylindrical portion 43D. Projecting.
An inner hole of the cylindrical boss 3As penetrates the cylindrical portion 3A.
A first switching pin 73 and a second switching pin 74 are slidably inserted into the inner holes of the left and right cylindrical boss portions 3As, 3As, respectively.

Referring to FIG. 7, in the first switching pin 73, a distal end cylindrical portion 73a and a proximal end cylindrical portion 73b are connected in a straight line by an intermediate connecting rod portion 73c.
The proximal cylindrical portion 73b has a smaller outer diameter than the distal cylindrical portion 73a.
Further, an engagement end 73ae having a reduced diameter protrudes from the distal end cylindrical portion 73a.
An end surface of the base end cylindrical portion 73b on the side of the intermediate connecting rod portion 73c forms a conical end surface 73bt.
The second switching pin 74 has the same shape, and the intermediate connecting rod portion 74c connects the distal end cylindrical portion 74a and the proximal end cylindrical portion 74b in a straight line.

On the other hand, as shown in FIG. 7, the intake-side switching drive shaft 71 is formed with a long hole 71a penetrating the shaft center.
The width of the long hole 71a is slightly larger than the diameter of the intermediate connecting rod portion 73c of the first switching pin 73, but smaller than the diameter of the proximal end cylindrical portion 73b.
On one end face of the long hole 71a of the intake side switching drive shaft 71, a cam surface 71C is formed with two concave curved surfaces 71Cv formed in a concave shape in a predetermined shape and continuously formed on the left and right sides via a flat surface 71Cp. Is configured.

  In the first switching pin 73, the intermediate connecting rod portion 73c passes through the elongated hole 71a of the intake side switching drive shaft 71, and is biased by the coil spring 75 so that the conical end surface 73bt of the base end cylindrical portion 73b is the intake side switching drive shaft. 71 is assembled in a state of being pressed and engaged with the cam surface 71C which is the opening end surface of the long hole 71a of the 71, so that when the intake-side switching drive shaft 71 moves in the axial direction, The cam surface 71C with which the conical end surface 73bt of the base cylindrical portion 73b of the first switching pin 73 sliding in the orthogonal direction abuts slides and is guided by the shape of the cam surface 71C so that the first switching pin 73 is axially moved. The linear motion cam mechanism Ca is configured to advance and retract in a direction perpendicular to the vertical axis.

As shown in FIG. 7, the first switching pin 73 and the second switching pin 74 are arranged in parallel with each other through the common long hole 71 a of the intake side switching drive shaft 71.
FIG. 7 shows a state in which the center of the concave curved surface 71Cv of the cam surface 71C of the intake side switching drive shaft 71 is located at the position of the first switching pin 73, and the first switching pin 73 is conical end surface on the concave curved surface 71Cv. The second switching pin 74 is in a position retreated by contacting the flat surface 71Cp of the cam surface 71C.

When the intake side switching drive shaft 71 moves to the right from this state, the conical end surface 73bt of the first switching pin 73 retreats up and down the inclined surface of the concave curved surface 71Cv from the center of the concave curved surface 71Cv, and comes into contact with the flat surface 71Cp. In the second switching pin 74, the conical end surface 74bt descends from the flat surface 71Cp on the inclined surface of the concave curved surface 71Cv and comes into contact with the center of the concave curved surface 71Cv.
In this way, the first switching pin 73 and the second switching pin 74 can be alternately advanced and retracted by the movement of the intake side switching drive shaft 71 in the axial direction.

Although not shown in the cylindrical portion 3B into which the exhaust side switching drive shaft 81 is slidably inserted in the axial direction, the first switching pin 83 and the second switching pin 84 are provided as in the cylindrical portion 3A. Two cylindrical boss portions 3Bs and 3Bs which are slidably inserted are formed adjacent to each other on the left and right, and the first switching pin 83 and the second switching pin 84 are common long holes of the exhaust side switching drive shaft 81. They are arranged in parallel with each other through 81a (see FIGS. 5 and 6).
As the exhaust side switching drive shaft 81 moves in the axial direction, the first switching pin 83 and the second switching pin 84 are axially moved by the cam surface 81C of the long hole 81a (the cam surface having the same shape as the cam surface 71C, see FIG. 8). The linear motion cam mechanism Cb is configured to advance and retract alternately in the direction perpendicular to the axis.

  As shown in FIG. 5, at least on the axial extension of the four stud bolts 7 on the right side on the front side (exhaust side) of the stud bolts 7 that overlap and fasten the cylinder block 2 and the cylinder head 3 to the crankcase 1. The exhaust side switching drive shaft 81 and the first and second switching pins 83 and 84 in the cylindrical boss portions 3Bs and 3Bs are arranged so as to partially overlap.

Referring to FIGS. 5 and 6, the left side wall 3U _L of the upper cylinder head 3U, intake side hydraulic actuator 77 for moving the intake-side switching drive shaft 71 in the axial direction is provided to protrude into the valve operating chamber 3d At the same time, an exhaust side hydraulic actuator 87 that moves the exhaust side switching drive shaft 81 in the axial direction is provided in the valve operating chamber 3d so as to be juxtaposed in front of the intake side hydraulic actuator 77.
That is, the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87 are formed integrally with the upper cylinder head 3U.

  As shown in FIG. 5, the axial extension of each of the leftmost two stud bolts 7, 7 out of the ten stud bolts 7, in which the cylinder block 2 and the cylinder head 3 are overlapped and fastened to the crankcase 1. Above, an intake side hydraulic actuator 77 and an exhaust side hydraulic actuator 87 are arranged so that at least a part thereof overlaps.

Referring to FIGS. 8 and 9, an intake side hydraulic actuator 77 includes an intake side actuator drive body 79 having a bottomed cylindrical shape in a circular hole-shaped housing inner chamber of an intake side actuator housing 78. 71 is fitted so as to be reciprocally slidable in the axial direction (left-right direction) of 71, and the left end portion of intake side switching drive shaft 71 is fitted to intake side actuator drive body 79 and moves integrally therewith.
The housing inner chamber of the intake side actuator housing 78 has its left opening closed by a lid member 76 and is divided into left and right sides by an intake side actuator driver 79 so as to be divided into a left side high speed side hydraulic chamber 78 _H and a right side low speed side hydraulic chamber 78. _L is configured.

Similarly, an exhaust-side hydraulic actuator 87 is fitted in a circular hole-shaped housing inner chamber of an exhaust-side actuator housing 88 so that an exhaust-side actuator driver 89 having a bottomed cylindrical shape is reciprocally slidable in the left-right direction. Thus, the left end portion of the exhaust side switching drive shaft 81 is fitted to the exhaust side actuator driving body 89 and moves integrally.
A housing inner chamber of the exhaust side actuator housing 88 is closed at the left side by a lid member 86 and is divided into left and right sides by an exhaust side actuator driver 89 to be divided into a left side high speed side hydraulic chamber 88 _H and a right side low speed side hydraulic chamber 88. _L is configured.

Referring to FIGS. 8 and 9, it communicates to the left side wall 3U _L of the upper cylinder head 3U, and the high-speed side hydraulic chambers 88 _H of the high-speed side hydraulic chambers 78 _H and the exhaust-side hydraulic actuator 87 of the intake-side hydraulic actuator 77 with high-speed side supply and discharge oil passage 90 _H is formed to, low-speed side supply and discharge oil passage that communicates the low-speed side hydraulic chamber 88 _L of the low-speed side hydraulic chambers 78 _L and the exhaust-side hydraulic actuator 87 of the intake-side hydraulic actuator 77 90 _L is formed.

Fast side supply and discharge oil passage 90 _H is open to the left end mating surface 3U _FL of the left end portion of the front surface of the front wall 3U _F of the high-speed side hydraulic chamber 88 above the _H penetrating into the front cylinder head 3U exhaust side hydraulic actuator 87 and which (Figure 10), the low-speed side supply and discharge oil passage 90 _L is open to the left end mating surface 3U _FL of the front wall 3U _F a low-speed hydraulic chamber 88 _L of the exhaust-side hydraulic actuator 87 through the front (FIG. 10).

The cylindrical portion facing the high-speed side supply and discharge oil passage 90 _H of the intake-side actuator drive member 79 forming the bottomed cylindrical intake side hydraulic actuator 77, since the long hole 79h is elongated in the axial direction is formed, communicating port opening to the housing chamber of the high-speed side supply and discharge oil passage 90 _H to be drilled to the intake side actuator housing 78, also move the intake-side actuator driver 79, the long holes 79h and the counter always cylindrical portion , it is possible to always communicating state speed side supply and discharge oil passage 90 _H and the high-speed side hydraulic chambers 78 _H.

Further, the front and rear of the cylindrical portion facing the high-speed side supply and discharge oil passage 90 _H of the exhaust-side actuator drive member 89 forming the bottomed cylindrical exhaust side hydraulic actuator 87, elongated in the axial direction elongated holes 89h, 89h because There is formed, communication port which opens into the housing interior of the high-speed side supply and discharge oil passage 90 _H to be drilled on the exhaust side actuator housing 88 is, even if the exhaust-side actuator driver 89 moves, always cylindrical portion elongated holes 89h, opposite the 89h, it is possible to always communicating state speed side supply and discharge oil passage 90 _H and the high-speed side hydraulic chambers 88 _H.

Incidentally, the low-speed side supply and discharge oil passage 90 _L is, even if the exhaust-side actuator driver 89 of the intake-side actuator drive member 79 and the exhaust-side hydraulic actuator 87 of the intake-side hydraulic actuator 77 moves to either the left and right, always intake side in the low speed side hydraulic chamber 88 _L communication with the low-speed side hydraulic chambers 78 _L and the exhaust-side hydraulic actuator 87 of the hydraulic actuator 77.

Figure 10 shows a left mating surface 3U _FL of the front surface of the front wall 3U _F of the upper cylinder head 3U, in the left mating surface 3U _FL, fast-side supply and discharge oil passage 90 _H and the low-speed side supply and discharge oil passage 90 _L is opened, and long grooves 90 _HH and 90 _LL are formed slightly obliquely to the right of each opening.

The left mating surface 3U _FL of the front surface of the front wall 3U _F of the upper cylinder head 3U, the linear solenoid valve 91 is attached.
8 and 9, in the linear solenoid valve 91, a sleeve 93 is provided as an extension of the electromagnetic solenoid 92 in which the plunger 92p moves in the electromagnetic coil 92c.
A spool valve 94 is slidably fitted in the sleeve 93, and is urged by a spring 95 so that the spool valve 94 abuts on the plunger 92p coaxially.

The linear solenoid valve 91 is attached to the left end mating surface 3U _FL which is the left end portion of the front surface of the upper cylinder head 3U in a posture in which a spool valve 94 coaxial with the plunger 92p of the electromagnetic solenoid 92 is oriented in the horizontal direction (FIG. 2). FIG. 3).
As shown in FIGS. 8 and 9, the linear solenoid valve 91 has a spool valve 94 that is parallel to the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 and that is directed in the left and right direction and moves in the left and right direction. .

  Therefore, when the electromagnetic coil 92c is excited, the plunger 92p protrudes to the left (LH) against the urging force of the spring 95 together with the spool valve 94 in the sleeve 93 (see FIG. 9), and the electromagnetic coil 92c is excited. When released, the spool valve 94 retreats to the right (RH) by the biasing force of the spring 95 (see FIG. 8).

The sleeve 93, a central hydraulic supply port 93 _I, and the high-speed side supply and discharge port 93 _H and the low-speed side supply and discharge port 93 _L located on both sides, located on either side thereof two supply and discharge ports 93 _H, 93 _L A pair of drain ports 93 _D and 93 _D are formed.
On the other hand, the spool valve 94 that slides sleeve 93 includes a central hydraulic supply groove 94 _I, a pair of drain groove 94 _D, 94 _D through the land on both sides are formed side by side in the axial direction.

8 and 9, a sleeve 93 of the linear solenoid valve 91 is schematically shown.
FIG. 11 shows an actual linear solenoid valve 91. The rear side surface of the sleeve 93 is a mating surface 93R. The mating surface 93R includes a hydraulic pressure supply port 93 _I and a high-speed side supply / discharge port. Openings of 93 _H , low speed side supply / discharge port 93 _L and drain port 93 _D are open. Through

The mating surfaces 93R is a side rear surface of the sleeve 93 of the linear solenoid valve 91 is engaged to the left mating surface 3U _FL is a left end portion of the front surface of the front wall 3U _F of the upper cylinder head 3U shown in FIG. 10, A linear solenoid valve 91 is attached to the upper cylinder head 3U.
Thus, the left end mating surface 3U _FL of the front wall 3U _F of the upper cylinder head 3U shown in Figure 10, the hydraulic pressure supply port of the sleeve 93 93 _I, the high-speed side supply and discharge port 93 _H, low speed side supply and discharge port 93 _L, opposite the respective opening of the drain port 93 _D, the long groove 90 _II, the fast-side supply and discharge oil passage 90 _H elongated groove 90 _HH, the low-speed side supply and discharge oil passage 90 _L long groove 90 _LL of hydraulic pressure supply passage 90 _{I, respectively,} drain Each opening of the long groove 90 _DD of the oil passage 90 _D is formed.

State shown in FIG. 8, the electromagnetic solenoid 92 of the linear solenoid valve 91 has retracted to the right (RH) spool valve 94 by the biasing force of the spring 95 in a non-energized, therefore, the long groove from the oil pressure supply passage 90 _I 90 pressure oil flows into the hydraulic pressure supply port 93 _I of the sleeve 93 through the _II is, the low-speed side supply and discharge oil of the left side wall 3U _L of the upper cylinder head 3U through hydraulic supply groove 94 _I from the low-speed side supply and discharge port 93 _L It flows into the passage 90 _L via the long groove 90 _LL and is supplied to the low speed side hydraulic chamber 78 _L of the intake side hydraulic actuator 77 through the low speed side hydraulic chamber 88 _L and the low speed side hydraulic chamber 88 _L of the exhaust side hydraulic actuator 87. As a result, the intake-side actuator driver 79 of the intake-side hydraulic actuator 77 and the exhaust-side actuator driver 89 of the exhaust-side hydraulic actuator 87 are pressed and moved to the left (LH).

Since the actuator drivers 79 and 89 of the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87 move to the left, from the high speed side hydraulic chambers 78 _H and 88 _{H of} the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87, respectively. pressure oil flows out to the high speed side supply and discharge oil passage 90 _H, further flows out from the high-speed side supply and discharge oil passage 90 _H via the long grooves 90 _HH speed side supply and discharge port 93 _H of the sleeve 93 of the linear solenoid valve 91, It is discharged to the drain oil passage 90 _D via the long grooves 90 _DD from the drain port 93 _D via the drain groove 94 _D.

Thus, when the electromagnetic solenoid 92 of the linear solenoid valve 91 is not energized, the low-pressure side hydraulic chambers 78 _L and 88 _L of the intake-side hydraulic actuator 77 and the exhaust-side hydraulic actuator 87 are provided as shown in FIG. Pressure oil is supplied, pressure oil flows out from the high-speed side hydraulic chambers 78 _H and 88 _H , and the actuator drive bodies 79 and 89 of the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87 are simultaneously moved to the left (LH ), The intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 that are integrally fitted to the actuator drive bodies 79 and 89 are also moved to the left (LH) at the same time.

When the electromagnetic solenoid 92 of the linear solenoid valve 91 is excited, as shown in FIG. 9, the spool valve 94 protrudes to the left (LH) against the biasing force of the spring 95, and the hydraulic pressure supply port 93 _{I of the} sleeve 93 the inflowing pressure oil flows through the long grooves 90 _HH speed side supply and discharge oil passage 90 _H of the left side wall 3U _L of via hydraulic supply groove 94 _I from the high-speed side supply and discharge port 93 _H upper cylinder head 3U Then, the air is supplied to the high speed side hydraulic chamber 78 _H of the intake side hydraulic actuator 77 through the high speed side hydraulic chamber 88 _H and the high speed side hydraulic chamber 88 _H of the exhaust side hydraulic actuator 87, thereby The actuator-side actuator 79 and the exhaust-side actuator driver 89 of the exhaust-side hydraulic actuator 87 are moved to the right (RH).

In addition, the pressure oil flows out from the low speed side hydraulic chambers 78 _L and 88 _{L of} the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87 to the low speed side supply / discharge oil passage 90 _L , and further from the low speed side supply / discharge oil passage 90 _L. to flow out to the low speed side supply and discharge port 93 _L of the electromagnetic solenoid 92 of the linear solenoid valve 91 via the long grooves 90 _LL, and is discharged from the drain port 93 _D to a drain oil passage 90 _D via the drain groove 94 _D.

As described above, when the electromagnetic solenoid 92 of the linear solenoid valve 91 is excited, the high pressure side hydraulic chambers 78 _H and 88 _H of the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87 are pressurized as shown in FIG. Oil is supplied and pressure oil flows out from the low speed side hydraulic chambers 78 _L and 88 _L , and the actuator drive bodies 79 and 89 of the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87 simultaneously move rightward. Therefore, the intake-side switching drive shaft 71 and the exhaust-side switching drive shaft 81 that are integrally fitted to the actuator drive bodies 79 and 89 are simultaneously moved to the right (RH).

  As described above, when the electromagnetic solenoid 92 of the linear solenoid valve 91 is de-energized and the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 move to the left (LH), the intake side cam switching shown in FIG. In the mechanism 70, the first switching pin 73 of each linear cam mechanism Ca is in a position advanced by contacting the concave curved surface 71Cv of the intake side switching drive shaft 71, and the second switching pin 74 is a flat surface of the cam surface 71C. It is in a position retreating against 71 Cp.

  The advanced first switching pin 73 engages with the annular lead groove 44c of the lead groove cylindrical portion 43D of the intake side cam carrier 43 that has moved to the right side, and the intake side cam carrier 43 does not move in the axial direction but is moved to the right side. Maintained in position.

When the intake side cam carrier 43 is at the right predetermined position (low speed side position), as shown in FIG. 12, the low speed side cam lobe 43B acts on the intake rocker arm 72 and is set to the cam profile of the low speed side cam lobe 43B. The intake valve 41 is operated according to the low-speed side valve operating characteristics.
That is, the internal combustion engine E is in a low speed operation state.

  When the electromagnetic solenoid 92 of the linear solenoid valve 91 is excited from this state and the intake side switching drive shaft 71 moves to the right, referring to FIG. 13, the first switching pin 73 has a conical end surface 73bt at the center of the concave curved surface 71Cv. The second switching pin 74 has a conical end surface 74bt descending from the flat surface 71Cp down the inclined surface of the concave curved surface 71Cv to the center of the concave curved surface 71Cv. Abut.

  Accordingly, the retracted first switching pin 73 comes out of the annular lead groove 44c of the intake side cam carrier 43, and the advanced second switching pin 74 is engaged with the left shift lead groove 44l. As shown in FIG. 13, the second switching pin 74 moves from the left shift lead groove 44l to the annular lead groove 44c and engages with the left shift lead groove 44l. The intake cam carrier 43 is maintained at a predetermined position on the left side.

When the intake side cam carrier 43 is at a predetermined position on the left side (high speed side position), as shown in FIG. 13, the high speed side cam lobe 43A acts on the intake rocker arm 72 to set the cam profile of the high speed side cam lobe 43A. The intake valve 41 is operated according to the high speed side valve operating characteristics.
That is, the internal combustion engine E is in a high speed operation state.

  When the intake side switching drive shaft 71 is moved to the left from this high speed operation state, the second switching pin 74 is retracted and comes out of the annular lead groove 44c, and the first switching pin 73 is advanced to move to the right shift lead. Since it engages with the groove 44r, the intake side cam carrier 43 is guided by the right shift lead groove 44r and moves to the right in the axial direction while rotating, and as shown in FIG. The position (low speed side position) is maintained, and the low speed side cam lobe 43B is in a low speed operation state in which it acts on the intake rocker arm 72.

  Similar to the operation of the intake side cam switching mechanism 70 due to the movement of the intake side switching drive shaft 71 by the excitation / non-excitation of the electromagnetic solenoid 92 of the linear solenoid valve 91 as described above, the exhaust side cam switching mechanism 80 is also driven by the exhaust side switching drive. It operates by the movement of the shaft 81.

Hereinafter, the oil supply passage for oil to the valve operating device will be described with reference to FIGS. 2 and 3 and FIGS.
An oil pump 20 is disposed near the oil pan 5 at the rear of the lower crankcase 1L (see FIG. 2).

2 and 3, the cylinder block 2, the cylinder head 3, and the cylinder head cover 4 that are stacked on the upper crankcase 1 </ b> U of the crankcase 1 are inclined slightly forward from the crankcase 1 to the cylinder axis Lc. Along the top.
Accordingly, as shown in FIG. 24 along the bent portion 1v cylinder front wall 2 _F was anteversion substantially vertical wall and the cylinder block 2 of the case front wall 1U _F of the upper crankcase 1U form, valleys V Are oriented in the left-right direction.

Referring to FIG. 3, an oil filter 21 is attached to the lower portion on the right side on the front surface of lower crankcase 1 </ b> L.
The oil pump 20 pumps up the oil accumulated in the oil pan 5 and pumps the oil to the oil filter 21 via an oil passage (not shown).

With reference to FIGS. 3 and 14, from the oil filter 21, upward along the front of the case front wall 1U _F of the lower crankcase 1L case front wall 1L _F and the upper crankcase 1U, upper crankcase 1U and case front toward the inside of the front valley portion V of the wall 1U _F, the first oil supply passage a1 is formed.

Then, the second oil supply path is formed in the vicinity of the bent portion 1v forming the valley V from the downstream end of the first oil supply path a1 reaching the inside of the valley V of the upper crankcase 1U to the left along the valley V. a2 is formed in the case front wall 1U _F of the upper crankcase 1U extend.

Referring to the upper crankcase 1U and 16 in FIG. 15, the left end is a downstream end of the second oil supply passage a2, third oil supply passage a3 extending rearward along the left side wall 1U _L of the upper crankcase 1U is Is formed.

The third oil supply passage a3 is configured as an outer pipe in which an oil passage pipe Pa3 forming the third oil supply passage a3 is exposed to the outside.
The third oil supply passage a3 is formed in the right side wall of the upper crankcase 1U cam chain 66 is formed a cam chain chamber 3c disposed along the left side wall 1U _L opposite.

From this third is a downstream end of the oil supply passage a3 rear, fourth oil supply passage a4 towards the inside of the left side wall 1U _L of the upper crankcase 1U is formed.
From the fourth oil supply passage a4, the fifth oil supply passage a5 extending upward are formed on the left wall 1U _L of the upper crankcase 1U, mating surfaces of the fifth oil supply passage a5 and the cylinder block 2 of the upper crankcase 1U Is open.

The left side wall 2 _L of the cylinder block 2, a sixth oil supply passage a6 extending in the vertical direction is formed, the sixth oil supply passage a6 has a lower end in the mating face between the upper crankcase 1U are open, the upper crank The upper end opening of the fifth oil supply passage a5 of the case 1U is combined with the fifth oil supply passage a5.
The upper end of the sixth oil supply passage a6 is open at the mating surface with the lower cylinder head 3L of the cylinder block 2.

The left side wall 3L _L of the lower cylinder head 3L is formed with a seventh oil supply passage a7 extending in the vertical direction. The seventh oil supply passage a7 has a lower end opened on the mating surface with the cylinder block 2, and the cylinder The upper end opening of the sixth oil supply passage a6 of the block 2 is combined and communicated with the sixth oil supply passage a6.
The seventh oil supply passage a7 has an upper end opened at the mating surface of the lower cylinder head 3L with the upper cylinder head 3U.

The left side wall 3U _L of the upper cylinder head 3U, is the eighth oil passage a8 extending vertically formed, the eighth oil passage a8 is open lower end to the mating surface of the lower cylinder head 3L, It is combined with the upper end opening of the seventh oil supply passage a7 of the lower cylinder head 3L and communicates with the seventh oil supply passage a7.

The eighth oil supply passage a8 has a lower end opened to the mating surface, but the upper end is bent forward to form a ninth oil supply passage a9.
Ninth oil supply passage a9 may extend substantially horizontally forward from the upper end of the eighth oil passage a8, and opens the front end to the left end mating surface 3U _FL of the front surface of the front wall 3Fr the upper cylinder head 3U described above.
That is, referring to FIG. 10, the ninth oil supply passage a9, the equivalent to the hydraulic pressure supply passage 90 _I, the front of the linear solenoid valve 91 of the upper cylinder head 3U are open to the left end mating surface 3U _FL attached .

The sixth oil supply passage a6 and the seventh oil supply passage a7 are formed to extend in the vertical direction along the left side walls 2 _L and 3L _L of the cylinder block 2 and the lower cylinder head 3L.
Sixth oil supply passage a6 seventh oil passage a7 is formed in the left side wall 2 _L, 3L _L opposite to the right side wall of the cylinder block 2 and a lower cylinder head 3L of the cam chain 66 is disposed .

21 to FIG. 23 illustrates only the flow path of the oil of the left side wall 3U in _RH of the upper cylinder head 3U.
Low-speed hydraulic chamber 88 _L and the high-speed side hydraulic chambers 88 _H and the low-speed side hydraulic chamber 78 _L and the high-speed side hydraulic chambers 78 _H of the intake-side hydraulic actuator 77 of the exhaust-side hydraulic actuator 87 are arranged in tandem The low-speed side hydraulic chambers 78 _L and 88 _{L communicate} with the low-speed side supply / discharge oil passage 90 _L , and the high-speed side hydraulic chambers 78 _H and 88 _H communicate with the high-speed side supply and discharge oil passage 90 _H.

Speed side supply and discharge oil passage 90 _L and the high-speed side supply and discharge oil passage 90 _H is respectively communicated with the long groove 90 _LL and long groove 90 _HH which is open to the left end mating surface 3U _FL of the upper cylinder head 3U extends forward, respectively.
Speed side supply and discharge oil passage 90 _L and the high-speed side supply and discharge oil passage 90 _H is parallel to the left and right oriented in the longitudinal direction, the eighth oil passage a8 is low speed side supply and discharge oil passage 90 _L It is disposed to extend between the high-speed side supply and discharge oil passage 90 _H in the vertical direction.

Ninth oil supply passage a9 extending forwardly from the upper end of the eighth oil passage a8 (hydraulic pressure supply passage 90 _I) is in communication with the open ended elongated groove 90 _II on the left end mating surface 3U _FL of the upper cylinder head 3U.
Further, the opened long groove 90 _DD from the drain oil passage 90 _D extends rearwardly to the left end mating surface 3U _FL.

The oil passage structure of the above actuator, oil that has flowed out is filtered from the oil filter 21, after flowing through the first oil supply passage a1 of the front wall 1U _F of the upper crankcase 1U upwards, along the valleys V flows through the second oil supply passage a2 to the left, then, flows through the third oil supply passage a3 along the left side wall 1U _L of the upper crankcase 1U backwards, then flows through the fourth oil supply passage a4, and the fifth oil supply passage a5 , then a fifth oil supply passage a5 sixth oil supply passage a6 of the left side wall 2L of the cylinder block 2 from the seventh oil passage a7 of the left side wall 3L _L of the lower cylinder head 3L, the left side wall 3U _L of the upper cylinder head 3U first 8 oil supply passage a8 sequentially flows upward.

Then, the left side wall 3U _L of the upper cylinder head 3U, oil that has reached the upper end of the eighth oil passage a8, the sleeve 93 of the ninth oil supply passage a9 (hydraulic pressure supply passage 90 _I) to flow forward linear solenoid valve 91 Flows in.

Oil flowing into the sleeve 93 of the linear solenoid valve 91 is controlled by the linear solenoid valve 91, the low-speed side supply and discharge oil passage 90 _L or high speed side supply and discharge oil passage 90 intake side hydraulic actuator 77 and the exhaust-side oil pressure by _H Oil is supplied to the actuator 87, and the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87 are driven.

Drain oil passage 90 _D of the upper cylinder head 3U is a treatment which extends somewhat rearwardly from the elongated groove 90 _DD, and opens downward as an oil discharge hole (first return oil passage) b1 bent downward (FIG. 20).
The oil discharged from the oil discharge hole b1 is poured on the upper surface of the upper lid wall 3Lt forming the combustion chamber 30 of the lower cylinder head 3L shown in FIG.
Lower cylinder head 3L is inclined forward, since the upper lid wall 3Lt is inclined forwardly downward, the oil discharged to the upper surface of the upper cover wall 3Lt flows forward, upper cover wall 3Lt and a front wall 3L _F It collects in the corner formed by.

With reference to FIGS. 15 and 18, the second return oil passage b2 extending front wall 3L _F downwardly open in the corner formed by the upper lid wall 3Lt the front wall 3L _F of the lower cylinder head 3L Two are formed on the left and right.
Referring to FIGS. 15 and 17, the cylinder block 2 connected below the lower cylinder head 3 </ b> L has a third return oil passage b <b> 3 that communicates with the second return oil passage b <b> 2 on the front wall 2 </ b> F in the left and right directions. It is formed so as to extend downward.

With reference to FIGS. 15 and 16, the upper crankcase 1U which is articulated under the cylinder block 2, before the fourth return oil path b4 communicating with the third return oil path b3 on the wall 1U _F are lateral 2 It is formed so as to extend downward.

As shown in FIG. 24, the second, third, and fourth return oil passages b2, b3, b4 are formed in an oblique vertical direction inclined forward along the front wall of the engine body.
The fourth return oil passage b4 of the upper crankcase 1U is further bent and extended downward to the third return oil passage b3 inclined forward of the cylinder block 2, and the fourth return oil passage b4 is The lower end is opened in the crank chamber.

  Therefore, the oil discharged from the oil discharge hole (first return oil passage) b1 of the upper cylinder head 3U is the second return oil b2 of the lower cylinder head 3L, the third return oil b3 of the cylinder block 2, and the upper crankcase. It flows through the 1U fourth return oil passage b4 and returns to the oil pan 5 from the crank chamber.

  As shown in FIG. 24, in the upper crankcase 1U, a second oil supply passage a2 extending in the left-right direction along the valley V is located on the inner side (rear side) of the fourth return oil passage b4.

Next, an oil passage structure for supplying oil to the bearings of the intake side camshaft 42 and the exhaust side camshaft 52 of the variable valve device 40 will be described.
The intake side camshaft 42 and the exhaust side camshaft 52 that are parallel to each other are fitted to the bearing surface 3vf that is oriented in the left-right direction and forms a semicircular arc surface of the plurality of bearing walls 3v, 3vr of the upper cylinder head 3U. It is pivotally supported so as to be sandwiched by 33.

Referring to FIG. 3, along the front face of the lower crankcase casing front wall of the lower crankcase 1L from the oil filter 21 attached to the front of 1L 1L _F and the upper crankcase 1U case front wall 1U _F above branches off from the middle of the first oil supply passage a1 which is formed to extend, the first oil supply passage c1 case front wall 1U _F of the upper crankcase 1U rightward extends to.

The first oil passage c1 of the upper crankcase 1U is bent at the right end and extends upward as a second oil passage c2.
The second oil supply passage c <b> 2 of the upper crankcase 1 </ b> U has an upper end opened on the mating surface with the cylinder block 2.

A third oil supply passage c3 extending in the vertical direction is formed on the right portion of the front wall 2F of the cylinder block 2, and the lower end of the third oil supply passage c3 is open at the mating surface with the upper crankcase 1U. It is combined with the upper end opening of the second oil supply passage a2 of the upper crankcase 1U and communicates with the second oil supply passage a2.
The upper end of the third oil supply passage c3 is open at the mating surface with the lower cylinder head 3L of the cylinder block 2.

A fourth oil supply passage c4 extending in the vertical direction is formed in the inner wall 3Lc of the cam chain chamber 3c of the lower cylinder head 3L, and the lower end of the fourth oil supply passage c4 opens on the mating surface with the cylinder block 2. It is combined with the upper end opening of the third oil supply passage a3 of the cylinder block 2 and communicates with the third oil supply passage a3.
The upper end of the fourth oil supply passage c4 is open at the mating surface of the lower cylinder head 3L with the upper cylinder head 3U.

Upper cylinder head 3U includes five bearing wall 3v between opposing front wall 3U _F and the rear wall 3U _B (3VR) are laid side by side, of the five bearing wall 3v (3VR, 3VL) The intake-side camshaft 42 and the exhaust-side camshaft 52 oriented in the left-right direction are fitted to the front and rear bearing surfaces 3vf, and are rotatably supported so as to be sandwiched between the camshaft holders 33 (see FIG. 4). .

  Referring to upper cylinder head 3U in FIG. 15, and FIGS. 19 and 20, the rightmost bearing wall 3vr along cam chain chamber 3c of upper cylinder head 3U has a fifth oil supply passage extending upward from the lower surface. c5 is formed, and the fifth oil supply passage c5 has a lower end opened on the mating surface with the lower cylinder head 3L, and is aligned with the upper end opening of the fourth oil supply passage c4 of the lower cylinder head 3L, so that the fourth oil supply It communicates with the road a4.

Fifth oil supply passage c5 has an upper end is closed, the sixth oil supply passage c6 rearward extends to the rear wall 3U _B from its upper end.
The wall 3U _B after the upper cylinder head 3U, seventh oil passage c7 is a rightmost bearing walls communicating oil passage extending to the left most bearing wall 3vl leftward from the bearing wall 3vr of are formed.
That is, the seventh oil passage (bearing walls communicating oil passage) c7 is an exhaust pipe 125 is formed in the wall 3U _B after the front wall 3U _F opposite extending.
The right end of the seventh oil supply passage c7 communicates with the sixth oil supply passage c6.

As shown in FIGS. 25 and 27, the seventh oil supply passage (inter-bearing wall communication oil passage) c7 is disposed below the semicircular bearing surface 3vf of the bearing wall 3v.
An arc groove 3vv is formed along the arc surface on the front and rear bearing surfaces 3vf of the leftmost bearing wall 3vl.
Referring to FIG. 27, in this bearing wall 3vl, an eighth oil supply path c8 which is branched from a seventh oil supply path (inter-bearing wall communication oil path) c7 extends obliquely upward. The upper end is opened in the circular arc groove 3vv of the rear bearing surface 3vf.

19, No. 7 oil passage (bearing walls communicating oil passage) c7 connecting oil path pipe Pc9 is bridged to the front wall 3U _F from the wall 3U _B after formed, connecting oil path pipe Pc9 after It is formed integrally in the wall 3U _B and the front wall 3U _F.
The connecting oil passage pipe Pc9 is formed on the right side of the leftmost bearing wall 3vl, and as shown in FIGS. 19 and 25, the connecting oil branch pipe Pc9 is branched from the seventh oil supply passage (communication oil passage between bearing walls) c7. A ninth oil supply passage c9 that is an oil passage is formed in the connection oil passage pipe Pc9.

As shown in FIG. 25, the ninth oil supply passage c9 extends forwardly downward slightly from the seventh oil passage c7 of the rear wall 3U _B side to the front wall 3U _F.
As shown in Figure 26, the rear wall 3U _B, leftward diagonally from a front end of the ninth oil passage c9, tenth oil passage c10 is sidewalls oil passage extends to the bearing wall 3VL.
An eleventh oil supply passage c11 that is a side wall oil passage extends downward from the upper end of the tenth oil supply passage c10 (see FIG. 26).

  Referring to FIG. 27, a twelfth oil supply passage c12, which is a second bearing wall oil passage, extends obliquely upward from the lower end of the eleventh oil supply passage c11 and forms an arc groove 3vv on the bearing surface 3vf on the front side of the bearing wall 3vl. The upper end is open.

  As described above, the ninth oil supply passage c9 that is the connecting oil passage, the tenth oil supply passage c10 that is the side wall oil passage, the eleventh oil supply passage c11, and the twelfth oil supply passage c12 that is the second bearing wall oil passage, Is also formed integrally with the upper cylinder head 3U.

  As shown in FIG. 5, an intake side camshaft 42 and an exhaust side camshaft 52 that are pivotally supported by five bearing walls 3v (3vr, 3vl) of the upper cylinder head 3U are pivotally supported. An exhaust side cam carrier 53 slidably fitted in the axial direction in the lead groove cylindrical portion 43D and the exhaust side cam shaft 52 of the intake side cam carrier 43 slidably fitted in the axial direction. The connecting oil passage pipe Pc9 is located below the lead groove cylindrical portion 53D adjacent to the cam lobes 53A and 53B.

Referring to FIG. 19, branching from a fifth oil supply passage c5 formed in the bearing wall 3vr of the upper cylinder head 3U in the vertical direction, the thirteenth oil supply passage c13 extends obliquely upward, and the bearing wall 3vr The upper end is opened to the mating surface 3a.
On this bearing wall 3vr, the camshaft holder 33 is overlapped with the mating surface 33a so that the intake side camshaft 42 and the exhaust side camshaft 52 are sandwiched and supported.

Referring to FIGS. 30 and 31, the camshaft holder 33 includes semicircular arc bearing surfaces 33f and 33f facing the front and rear bearing surfaces 3vf and 3vf forming the semicircular arc surface of the bearing wall 3vr.
In the bearing surfaces 33f and 33f, arc grooves 33fv and 33fv are formed along the arc surface.
On the mating surface 33a between the front and rear bearing surfaces 33f and 33f of the camshaft holder 33, a communication groove 33av that communicates the front and rear arc grooves 33fv and 33fv is formed.
A part of the communication groove 33av bulges to the left to form a bulging portion 33ap.

When this camshaft holder 33 is overlaid on the bearing wall 3vr, the bulging portion 33ap of the communication groove 33av of the camshaft holder 33 is formed at the upper end opening of the thirteenth oil supply passage c13 opened on the mating surface 3a of the bearing wall 3vr. Opposite.
Accordingly, the oil flows out from the thirteenth oil supply passage c13 to the bulging portion 33ap of the camshaft holder 33, flows from the bulging portion 33ap through the communication groove 33av, and is supplied to the front and rear arc grooves 33fv and 33fv. Each journal portion of the shaft 42 and the exhaust camshaft 52 is lubricated.

The oil passage structure of the bearing above the camshaft, oil flowing out into the first oil supply passage a1 of the front wall 1U _F of the upper crankcase 1U is filtered from the oil filter 21 flows through the first oil supply passage a1 upward The first oil supply passage c1 branched rightward from the first oil supply passage a1 flows to the right, the second oil supply passage c2 flows upward at the right end thereof, and then the third oil supply passage c3 of the cylinder block 2, the lower cylinder The oil flows through the fourth oil supply passage c4 of the head 3L and the fifth oil supply passage c5 of the upper cylinder head 3U in order.

In the upper cylinder head 3U, the oil that has reached the upper end of the fifth oil supply passage c5 flows rearward through the sixth oil supply passage c6 formed in the bearing wall 3vr, and then the seventh oil supply formed in the rear wall 3UB. It flows on the road c7 to the left.
The oil flowing through the seventh oil supply passage c7 flows into the eighth oil supply passage c8 branched by the left bearing wall 3vl, flows out into the arc groove 3vv of the bearing surface 3vf on the rear side of the bearing wall 3vl, and the bearing surface on the rear side. Lubricate 3 vf.

Moreover, the oil flowing through the seventh oil passage c7 flows forward branches to the ninth oil supply passage c9 formed in the middle of the connecting oil pipe PC 9, it reaches the front wall 3U _F side, front wall 3U _F side After flowing in the tenth oil supply passage c10 and the eleventh oil supply passage c11 formed in the above, the oil flows into the twelfth oil supply passage c12 formed in the bearing wall 3vl and enters the arc groove 3vv of the bearing surface 3vf on the front side of the bearing wall 3vl. It flows out and lubricates the front bearing surface 3vf.

  Furthermore, in the bearing wall 3vr on the right side of the upper cylinder head 3U, the oil that has flowed from the thirteenth oil supply passage c13 branched from the fifth oil supply passage c5 into the communication groove 33av of the camshaft holder 33 enters the front and rear arc grooves 33fv, 33fv. The flow is divided to lubricate the front and rear bearing surfaces 33f and 33f of the camshaft holder 33 and the front and rear bearing surfaces 3vf and 3vf of the bearing wall 3vr.

As described above, the embodiment of the oil passage structure of the internal combustion engine according to the present invention described in detail has the following effects.
As shown in FIG. 19, the seventh oil supply passage supplying a plurality of bearing walls 3v which is installed between a rear wall 3U _B and the front wall 3U _F of the upper cylinder head 3U, 3VL, communicates between 3vr oil ( bearing walls communicating oil passage) c7 is, is formed in a rear wall 3U _B, the supplying oil to the bearing surface 3vf the bearing wall 3vl branches off from the seventh oil passage (bearing walls communicating oil passage) c7 Since 8 oil supply passages (first bearing wall oil passages) c8 are formed integrally with the bearing wall 3vl, there is no oil leakage, the number of parts can be reduced, the number of assembly steps can be reduced, and the productivity can be improved. , Low cost.

  As shown in FIG. 27, the seventh oil supply passage (inter-bearing wall communication oil passage) c7 is disposed below the bearing surface 3vf of the bearing wall 3vl. Is easily removed to the bearing surface 3vf.

Referring to FIGS. 2 and 19, the wall 3U _B after the seventh oil passage (bearing walls communicating oil passage) c7 is formed, the rear wall of the front wall 3U _F opposite to the exhaust pipe 125 extends since in 3U _B, by the exhaust pipe 125 to form a seventh oil passage (bearing walls communicating oil passage) c7 to the wall 3U _B after the front wall 3U _F opposite to high temperature extended, oil Heating can be avoided.

Referring to FIG. 19, the variable valve device 40 includes two camshafts 42, 52, which are rotatably supported by bearing walls 3 v, 3 vl, 3 vr, and a seventh oil supply path (communication between bearing walls). oil passage) c7 connecting oil path pipe Pc9 from the wall 3U _B after one formed on the other of the front wall 3U _F of, are bridged, it is formed integrally with the rear wall 3U _B and the front wall 3U _F, 7 oil supply passage ninth oil supply path branched from (bearing walls communicating oil passage) c7 (connecting oil path) c9 are formed on the connecting oil path pipe PC 9, before the ninth oil supply passage in the wall 3U _F (connecting oil path) c9 10 oil supply passage extending in the bearing wall 3VL (sidewall oil passage) c10 is formed, 12 supplies a tenth oil passage oil from (the side wall oil passage) c10 to the bearing surface 3vf of the front wall 3U _F side of the bearing wall 3VL An oil supply passage (second bearing wall oil passage) c12 is formed in the bearing wall 3vl.
That is, the ninth oil supply path (connection oil path) c9, the tenth oil supply path (side wall oil path) c10, and the twelfth oil supply path (second bearing wall oil path) c12 are all formed integrally with the upper cylinder head 3U. As a result, the number of parts can be reduced, the number of assembly steps can be reduced, and the productivity can be improved.

  As shown in FIG. 5, an intake side camshaft 42 and an exhaust side camshaft 52 that are pivotally supported by five bearing walls 3v (3vr, 3vl) of the upper cylinder head 3U are pivotally supported. An exhaust side cam carrier 53 slidably fitted in the axial direction in the lead groove cylindrical portion 43D and the exhaust side cam shaft 52 of the intake side cam carrier 43 slidably fitted in the axial direction. Since the connecting oil passage pipe Pc9 is located below the lead groove cylindrical portion 53D adjacent to the cam lobes 53A and 53B, the connecting oil passage pipe Pc9 is brought close to the intake side cam carrier 43 and the exhaust side cam carrier 53. The internal combustion engine E can be downsized by effectively using the space.

  In the present embodiment, the connection oil passage pipe Pc9 having the eighth oil supply passage (first bearing wall oil passage) c8 and the ninth oil supply passage (connection oil passage) c9 adjacent to the leftmost bearing wall 3vl is provided. The oil is supplied to the bearing surface 3vf of the bearing wall 3vl, but the three bearing walls 3v between the left and right bearing walls 3vl and 3vr are also connected to the eighth oil supply path (first bearing wall oil path) c8. A corresponding oil passage may correspond to the corresponding first bearing wall oil passage and the ninth oil supply passage (connection oil passage) c9, and oil may be supplied to the bearing surface 3vf of the bearing wall 3v.

The seventh oil passage c7 is a bearing walls communicating oil passage, which had been formed in the wall 3U _B after the upper cylinder head 3U, a lower cylinder head 3L and the upper cylinder head 3U of mutual mating plane In addition, the seventh groove (carrying oil passage between the bearing walls) c7 may be configured by forming grooves facing each other and combining the grooves facing each other.

Next, another second embodiment of the present invention will be described with reference to FIGS.
The oil passage structure of the internal combustion engine according to the second embodiment has substantially the same structure as the oil passage structure of the internal combustion engine in the above embodiment except for a part of the cylinder head 3, and the same members use the same reference numerals. I will do it.

  That is, the crankcase 1 and the cylinder block 2 are the same as those in the above-described embodiment, and the upper cylinder head 3U and the lower cylinder head 3L which are divided into two parts above and below the cylinder head 3 are substantially the same as those in the above-described embodiment. Same but partially different.

Lower cylinder head 3L, referring to FIG. 32 which is a top view, the mating surface 3Laf elongated in the left and right of the front wall 3L _F of mating surfaces 3La the upper cylinder head 3U, left and right groove line 3Lv Are formed to extend linearly.
The groove 3Lv passes through the front of the three plug-insertion tube portions 3vp from the right end near the cam chain chamber 3c to the left end in front of the leftmost plug-insertion tube portion 3vp.

  Referring to FIG. 32, a fourth oil supply passage c4 is formed extending in the vertical direction on the inner wall 3Lc of the cam chain chamber 3c, and the first branch oil supply passage d1 branched from the middle of the fourth oil supply passage c4 is formed. , Connected to and communicated with the right end of the groove 3Lv.

The upper cylinder head 3U overlaid on the lower cylinder head 3L has a front wall 3U as compared to the upper cylinder head 3U shown in FIGS. 19 and 20 in the previous embodiment with reference to FIGS. no equivalent to connecting oil pipe Pc9 connecting the _F and rear wall 3U _B, fifth, sixth, seventh, eighth oil passage c5, c6, c7, although c8 is present, ninth oil supply passage There are no tenth, eleventh, twelfth and thirteenth oil supply passages c10, c11, c12, c13 after c9.

Upper cylinder head 3U, referring to FIG. 34 which is a bottom view, the mating surface 3Uaf elongated in the left and right of the front wall 3U _F of mating surfaces 3Ua the lower cylinder head 3L, left and right groove line 3Uv Are formed to extend linearly.
Mating surface 3Uaf of the front wall 3U _F of the upper cylinder head 3U is superimposed on the mating face 3Laf of the front wall 3L _F of the lower cylinder head 3L, it is formed in the groove line 3Uv and mating surface 3Laf formed on the mating surface 3Uaf The groove 3Lv facing each other is combined to form a second branch oil supply path d2.

The second branch oil supply passage d2 is a second oil communication passage between the bearing walls extending from the right end through the three bearing walls 3v to the leftmost bearing wall 3vl.
The second branch oil passage (second bearing wall communication oil passage) d2 communicates with the first branch oil passage d1 branched from the middle of the fourth oil passage c4, and is divided into the first branch oil passage d1. Oil flows into the second branch oil supply passage (second bearing wall communication oil passage) d2.

Referring to FIG. 33 which is a top view of the upper cylinder head 3U, semicircular bearing surfaces 3vf are formed before and after the plug-insertion tube portions 3vp of the four bearing walls 3v, 3v, 3v, 3vl. In each bearing surface 3vf, an arc groove 3vv is formed along the arc surface.
An intake side camshaft 42 is rotatably supported on the rear bearing surface 3v, and an exhaust side camshaft 52 is rotatably supported on the front bearing surface 3v.

Referring to FIG. 35, arcuate groove 3vv of four rear bearing surfaces (first bearing surface) 3vf branches off from seventh oil supply passage (communication oil passage between bearing walls) c7 and extends obliquely upward. The upper ends of the four eighth oil supply passages c8 which are the bearing wall oil passages are opened.
The arcuate grooves 3vv of the four front bearing surfaces (second bearing surfaces) 3vf branch off from the second branch oil supply passage (second bearing wall communication oil passage) d2 and extend obliquely upward. The upper ends of the four third branch oil supply passages d3 that are bearing wall oil passages are open.

Accordingly, the rear bearing surfaces (first bearing surfaces) 3vf on the four bearing walls 3v, 3v, 3v, 3vl that rotatably support the intake camshaft 42 are provided on the rear bearing surfaces. the seventh oil passage eighth oil passage c8 is (first bearing walls communicating oil passage) c7 and the first bearing wall oil passage formed in the wall 3U _B after closer (a first bearing surface) Reserved Flowed oil is supplied.

On the other hand, each front bearing surface (first bearing surface) 3vf of the four bearing walls 3v, 3v, 3v, 3vl that rotatably supports the exhaust camshaft 52 includes a front bearing surface (first bearing surface). The second branch oil supply passage (the second bearing wall communication) is formed by combining the grooves 3Uv and 3Lv formed on the mating surfaces 3Uaf and 3Laf of the front walls 3U _F and 3L _F closer to the bearing surface 3vf. Oil that has flowed through the oil path) d2 and the third branch oil supply path d3 that is the second bearing wall oil path is supplied.

  Therefore, oil can be efficiently supplied evenly to the first and second bearing surfaces 3vf and 3vf, which are the front and rear bearing surfaces of the bearing walls 3v, 3v, 3v, and 3vl, and can be lubricated.

Between the second bearing walls that allow the oil to flow between the plurality of bearing walls on the mating surfaces 3Uaf and 3Laf of the upper cylinder head 3U and the lower cylinder head 3L that are divided into two parts above and below the cylinder head 3 Since the grooves 3Uv and 3Lv constituting the communication oil passage d2 are respectively formed, the second inter-bearing wall communication oil passage d2 is formed at the stage of casting for casting the upper cylinder head 3U and the lower cylinder head 3L. The grooves 3Uv and 3Lv can be formed, and the oil passage can be easily formed.
In FIG. 35, a camshaft holder 33 'that has a semicircular arc surface and is supported so as to sandwich the camshaft with the bearing wall 3vl is superimposed on the bearing wall 3vl.

  Although the oil passage structure of the internal combustion engine according to the embodiment of the present invention has been described above, the aspect of the present invention is not limited to the above embodiment, and can be implemented in various aspects within the scope of the gist of the present invention. Is included.

  Although the upper crankcase 1U and the cylinder block 2 are separate from each other in the engine body of the internal combustion engine of the present embodiment, the engine main body in which the upper crankcase 1U and the cylinder block 2 are integrally formed is also applied.

  Further, the motorcycle on which the power unit having the oil passage structure of the internal combustion engine of the present invention is mounted is not limited to the saddle riding type motorcycle 1 of the embodiment, but a scooter type, a three wheel, a four wheel buggy, etc. Various straddle-type vehicles may be used as long as the vehicle has the requirements of claim 1.

Pu ... Power unit, E ... Internal combustion engine, Eh ... Engine body, M ... Transmission, V ... Tanibe,
a1 ... 1st oil supply path, a2 ... 2nd oil supply path, a3 ... 3rd oil supply path, a4, a5 ... 4th, 5th oil supply path, a6, a7, a8 ... 6th, 7th, 8th oil supply path, a9 ... ninth oil supply passage, Pa3 ... oil passage pipe,
b1, b2, b3, b4 ... 1st, 2nd, 3rd, 4th return oil passage,
c1, c2, c3, c4, c5, c6 ... 1st, 2nd, 3rd, 4th, 5th, 6th oil supply passage, c7 ... 7th oil supply passage (communication oil passage between bearing walls), c8 ... 8 oil supply passage (first bearing wall oil passage), c9... 9th oil supply passage (connection oil passage), c10... 10th oil supply passage (side wall oil passage), c11... 11th oil supply passage, c12. (Second bearing wall oil passage), c13 ... 13th oil supply passage, Pc9 ... connection oil passage pipe,
d1 ... first branch oil passage, d2 ... second branch oil passage (second bearing wall communication oil passage), d3 ... third branch oil passage (second bearing wall oil passage),
1 ... Crankcase, 1L ... lower crankcase, 1L F _... case front wall, 1U ... upper crankcase, 1U F _... case front wall, 1 v ... bent portion, 1U L _... left wall,
2 ... Cylinder block, _2F ... Front wall, _2L ... Left side wall,
3 ... Cylinder head, 3L ... lower cylinder head, 3L F _... front wall, 3La, LAF ... mating face, 3Lv ... groove line, 3U ... upper cylinder head, 3U F _... front wall, 3U B _... rear wall, 3U _L ... left wall, 3Ua, 3Uaf ... mating surface, 3Uv ... groove, 3U _FL ... left end mating surface, 3v, 3vr, 3vl ... bearing wall, 3vf ... bearing surface, 3vv ... arc groove, 3c ... cam chain chamber,
4 ... Cylinder head cover, 5 ... Oil pan, 7 ... Stud bolt,
10 ... Crankshaft, 11 ... Main shaft, 12 ... Counter shaft,
20 ... oil pump, 21 ... oil filter,
30 ... Combustion chamber, 33, 33 '... Camshaft holder,
40 ... Variable valve gear,
41 ... intake valve, 42 ... intake side camshaft, 43 ... intake side cam carrier, 43A ... high speed side cam lobe, 43B ... low speed side cam lobe, 43D ... lead groove cylindrical part, 44 ... lead groove, 44c ... annular lead groove, 44l ... Left shift lead groove, 44r ... Right shift lead groove, 47 ... Suction driven gear,
51 ... Exhaust valve, 52 ... Exhaust side camshaft, 53 ... Exhaust side cam carrier, 53A ... High speed side cam lobe, 53B ... Low speed side cam lobe, 53D ... Lead groove cylindrical part, 54 ... Lead groove, 54c ... Ring lead groove, 54l ... Left shift lead groove, 54r ... Right shift lead groove, 57 ... Exhaust side driven gear, 61 ... Idle gear, 62 ... Idle chain sprocket, 66 ... Cam chain,
70 ... Intake side cam switching mechanism, 71 ... Intake side switching drive shaft, 72 ... Intake rocker arm, Ca ... Cam mechanism, 73 ... First switching pin, 74 ... Second switching pin, 75 ... Coil spring, 76 ... Lid member, 77 ... Intake side hydraulic actuator, 78 ... Intake side actuator housing, 79 ... Intake side actuator driver, 79h ... Long hole,
80 ... exhaust side cam switching mechanism, 81 ... exhaust side switching drive shaft, 82 ... exhaust rocker arm, Cb ... cam mechanism, 83 ... first switching pin, 84 ... second switching pin, 86 ... lid member, 87 ... exhaust side hydraulic pressure Actuator, 88 ... Exhaust side actuator housing, 89 ... Exhaust side actuator driver, 89h ... Long hole,
90 _H : High speed side oil supply / discharge passage, 90 _HH : Long groove, 90 _L : Low speed side oil supply / discharge passage, 90 _RR : Long groove,
91 ... linear solenoid valve, 92 ... electromagnetic solenoid, 92c ... electromagnetic coil, 92p ... plunger, 93 ... sleeve, 93R ... mating face, 93 _{I ...} hydraulic supply port, 93 _{H ...} high speed side supply and discharge port, 93 _{L ...} low-speed Supply / discharge port, 93 _D ... Drain port, 94 ... Spool valve, 94 _I ... Hydraulic supply groove, 94 _D ... Drain groove, 95 ... Spring,
100: Motorcycle, 101 ..., 102 ... Head pipe, 103 ... Main frame, 104 ... Seat rail, 105 ... Front fork, 106 ... Front wheel, 107 ... Pivot shaft, 108 ... Swing arm, 109 ... Rear wheel, 110 ... Link Mechanism: 111 ... Rear cushion, 112 ... Travel drive sprocket, 113 ... Travel driven sprocket, 114 ... Travel drive chain, 116 ... Fuel tank, 117 ... Main seat, 118 ... Pillion seat, 121 ... Throttle body, 122 ... Air cleaner, 125 …Exhaust pipe.

Claims (6)

An engine body (Eh) is constructed by superimposing a cylinder head (3) on a cylinder block (2) provided upward from the crankcase (1), and is fastened integrally with the cylinder head (3). The camshaft (42, 52) of the valve gear (40) is rotatably supported by at least two bearing walls (3v, 3vl, 3vr) installed between the side walls (3U _F , 3U _B ), In the oil passage structure of the internal combustion engine in which an oil passage for supplying oil to the bearing surface (3vf) of the bearing wall (3v, 3vl, 3vr) of the cylinder head (3) is provided in the engine body (Eh),
The cylinder head (3U) includes a communication oil passage (c7) between the bearing walls that allows oil to flow between the plurality of bearing walls (3v, 3vl, 3vr), and a communication oil passage (c7) between the bearing walls. A bearing wall oil passage (c8) that branches and supplies oil to the bearing surface (3vf) of the bearing wall (3vl),
The bearing wall communication oil passage (c7) is formed on one side wall (3U _B ) of the opposite side wall (3U _F , 3U _B ),
The oil passage structure of an internal combustion engine, wherein the bearing wall oil passage (c8) is formed in the bearing wall (3vl).   2. The oil passage structure for an internal combustion engine according to claim 1, wherein the bearing wall communication oil passage (c <b> 7) is disposed below a bearing surface (3 vf) of the bearing wall (3 vl). One side wall (3U _B ) where the bearing wall communication oil passage (c7) is formed is a side wall opposite to the side wall (3U _F ) from which the exhaust pipe (125) extends. An oil passage structure for an internal combustion engine according to claim 1 or 2. The valve gear (40) has two parallel camshafts (42, 52) rotatably supported on at least two bearing walls (3vl, 3vr),
A connecting oil passage pipe (Pc9) is constructed from one side wall (3U _B ) where the bearing wall communication oil passage (c7) is formed to the other side wall (3U _F ), and both side walls (3U _F , 3U _B ) Integrally formed,
A connection oil passage (c9) branched from the bearing wall communication oil passage (c7) is formed in the connection oil passage pipe (Pc9),
A side wall oil passage (c10) extending from the connection oil passage (c9) to the bearing wall (3vl) is formed on the other side wall (3U _F ),
The bearing wall oil passage (c8) is a first bearing wall oil passage, and oil is supplied from the side wall oil passage (c10) to the bearing surface (3vf) on the other side wall (3U _F ) side of the bearing wall (3vl). The oil passage structure of the internal combustion engine according to any one of claims 1 to 3, wherein a second bearing wall oil passage (c12) to be supplied is formed in the bearing wall (3vl). The valve gear (40)
A camshaft (42, 52) oriented in the left-right vehicle width direction provided rotatably in the cylinder head (3);
A plurality of cam lobes (43A, 43B, 53A, 43A, 43B, 53A, which are cylindrical members that are fitted to the outer periphery of the camshaft (42, 52) so that relative rotation is prohibited and slidable in the axial direction. 53B) a cam carrier (43, 53) formed adjacent in the axial direction;
A cam switching mechanism (70, 80) for switching the cam lobe (43A, 43B, 53A, 53B) operating on the valve (41, 51) by moving the cam carrier (43, 53) in the axial direction,
The connecting oil passage pipe (Pc9) is located below a cylindrical portion (43D, 53D) adjacent to the cam lobe (43A, 43B, 53A, 53B) of the cam carrier (43, 53). Item 5. An oil passage structure of an internal combustion engine according to Item 4. The cylinder head (3) is composed of an upper cylinder head (3U) and a lower cylinder head (3L) which are divided into upper and lower parts.
The upper cylinder head (3U) includes the bearing walls (3v, 3vl, 3vr) that rotatably support the two parallel camshafts (42; 52),
The upper cylinder head (3U) and the lower cylinder head on the other side wall (3U _F ; 3L _F ) opposite to the one side wall (3U _B ) in which the bearing wall communication oil passage (c7) is formed. On the mating surfaces (3Uaf; 3Laf) of (3L), a second oil passage (d2) between the bearing walls (d2) is formed to allow oil to flow between the plurality of bearing walls (3v, 3vl). Grooves (3Uv; 3Lv) are formed,
A second bearing surface (3v, 3vl) of the bearing wall (3v, 3vl) is branched from the second bearing wall communication oil passage (d2) to the bearing wall (3v, 3vl) of the upper cylinder head (3U). The oil passage structure of the internal combustion engine according to any one of claims 1 to 3, wherein a second bearing wall oil passage (d3) for supplying oil to 3vf) is formed.

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