ES2688899T3 - Straddle Type Vehicle - Google Patents

Abstract

A straddle type vehicle including, supported for tilting movement in a vehicle frame, a power unit (20) including an OHC type internal combustion engine (30) and a continuously variable transmission of the belt type ( twenty-one); the internal combustion engine of the OHC type (30) having an axial cylinder line (Cc) tilted to a large extent and provided with a plurality of tilting arms (57, 58) arranged and supported for tilting movement in a mutually contiguous relationship on a tilting arm axis (55) and operable in an interlocking relationship with motor valves (61, 62); a connecting pin (71) mounted for movement in an axial direction of the swing arm axis (55) in the swing arms (57, 58) positioned adjacent to each other is arranged so that it is movable between a connection position in the that the connecting pin (71) connects the swinging arms (57, 58) positioned adjacent to each other for integral swinging and a disconnecting position in which the connecting pin (71) disconnects the swinging arms (57) , 58) from one another to allow independent swinging of each of the swinging arms (57, 58); a pressure force transmission element (74, 76) being provided that transmits pressure force from a source of pressure force generation (75) disposed outside the internal combustion engine of the OHC type (30) to the connecting pin (71 ) to move the connecting pin (71) in the vehicle width direction, where the OHC type internal combustion engine (30) has side walls (100L, 100R) directed in the vehicle width direction and walls sides (100U, 100S) directed in the vertical direction, the lateral walls jointly assuming a rectangular tubular shape, the source of pressure force generation (75) being mounted on one of the side walls (100L, 100R) directed in the direction across the width of the vehicle, and part of the vehicle frame is disposed on an outer side of the source of pressure force generation (75) in the width direction of the vehicle, where the vehicle frame i It includes a front tube (2), a down tube (3) that extends down the front tube (2), and a pair of left and right floor tubes (4) that extend backwards under a floor section (1c), which is arranged between a front section of the vehicle body (1f) and a rear section of the vehicle body (1r), of the descending tube (3), which rises obliquely upwards in a rear portion of the section of ground (1c) and extending backwards, and the source of pressure force generation (75) is located forward of the rear portions of the floor pipes (4) that rise obliquely upward and extend backward, as seen in side view, where the rear section of the vehicle body (1r) including the source of pressure force generation (75) is covered by the left and right sides with a body cover (29e).

Description

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DESCRIPTION

Straddle type vehicle [Technical field]

The present invention relates to a vehicle of the astride type [Background of the invention]

Among the internal combustion engines of the OHC type where a valve mechanism such as a camshaft is configured in a cylinder head, a variable valve apparatus where the valve timing can be changed is already known. In the variable valve apparatus of the type just described, tilting arms are arranged close to each other to convert and transmit the camshaft rotation to and as an opening and closing movement of engine valves. A connecting pin moves in the tilting arms arranged adjacent to each other. The connecting pin is movable between a connecting position in which it connects the tilting arms to each other for integral tilting movement and a disconnecting position in which it allows the tilting arms to swing independently of each other to thereby change the timing of valve.

The applicant of the present application proposed in an earlier application an example of a variable valve apparatus (see Japanese Patent Publication number 2012-77741; hereafter also referred to as Patent Document 1). In the variable valve apparatus, a solenoid is used as a source of pressure force generation to move the connecting pin. An operative portion or solenoid rod moves the connecting pin through a push rod (transmission rod (power) or pressure force transmission element) supported for sliding movement in the cylinder head.

In the OHC type internal combustion engine described in Patent Document 1, a spark plug is arranged protruding on a wall face of the cylinder head on which the solenoid is mounted.

Since the spark plug is mounted on the same wall face so that it is inserted obliquely from the cylinder head cover side, when the spark plug is maintained, the spark plug is moved so that it is mounted or disassemble in one direction of an axial line directed by the spark plug in the assembled state.

In the variable valve apparatus described in Patent Document 1, the solenoid operating rod is inserted into a sliding hole of the cylinder head configured to support the thrust rod (power transmission rod) for sliding movement. In addition, an interleaved interior space (space) interspersed between the operating rod and the push rod has been formed in the same sliding hole, and an oil supply hole (oil supply hole) in communication with the interleaved interior space It has formed above the interspersed interior space.

The variable valve apparatus has a function as an oil damper that suppresses, when the interleaved interior space is filled with oil supplied from the oil supply hole, the collision of the operating stem with the push rod by operation of the solenoid and dampens the impact and vibration of the collision.

In the variable valve apparatus described in Patent Document 1, the connecting pin that moves in the swing arm is disposed in an upwardly bent position (cylinder head cover side in the axial linear direction of the cylinder) with respect to a tilting arm axis between the tilting arm axis and a roller that contacts an eccentric lobe of an end portion of the tilting arm on the camshaft side. Also the transmission rod acting on the connecting pin is disposed in an upwardly bent portion of an upper end face of the cylinder head in a position of coupling face between the cylinder head and the cylinder head cover above the swing arm shaft.

[Summary of the invention]

[Problem to solve with the invention]

In Patent Document 1, the solenoid is placed comparatively close to the cylinder head cover rather than the spark plug, and the axial line directed by the spark plug as seen in the direction of an axial cylinder line overlaps with the solenoid as depicted in Figure 2 of Patent Document 1. Therefore, when the spark plug is moved for assembly or disassembly in the axial linear direction directed by the spark plug, the solenoid constitutes an obstacle and the Maintenance operation is not easy.

JP 03-029486 B2 describes an internal combustion engine of an alternative type of cycle suspension. An eccentric side inlet swing arm, a valve side inlet swing arm and a gear

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Timing are mounted on a swing arm shaft. Shift pins are mounted on these swingarms without sliding movement.

In particular, where the OHC type internal combustion engine is mounted on a straddle type vehicle in which it is not easy to secure a cylinder head length in the axial linear direction of the cylinder, the spark plug and The solenoid are probably placed close to each other. This makes it more difficult to secure the maintenance space around the spark plug.

A typical vehicle of the astride type is described, for example, in EP 2543834 A1.

The present invention has been carried out in view of the matter just described and provides a variable valve apparatus for an internal combustion engine of the OHC type that can maintain a good maintenance operation of a spark plug while achieving the miniaturization of a cylinder head. For this purpose, a source of pressure force generation mounted on a wall face of a cylinder head on which the spark plug is mounted, is arranged in a position that is not far from the spark plug and in which The source of pressure force generation does not constitute an obstacle for an operation of assembly and disassembly of the spark plug.

In addition, the oil supply hole of Patent document 1 has been formed in a position where it completely faces the interior space sandwiched between the operating rod and the push rod when the solenoid is in an inactive state. Therefore, if, by the operation of the solenoid, the operating rod starts the movement towards the pushing rod, then the oil introduced into the interleaved interior space is intercalated and it is likely that it will overflow from the oil supply hole and there is a possibility of that the function as an oil damper is degraded due to oil leakage. Therefore, it is desired to use the function more effectively as an oil buffer.

The present invention has been realized in view of the situation described above. Another object of the present invention is to provide a variable valve apparatus for an internal combustion engine of the OHC type capable of improving a function as an oil damper by the oil to be supplied between an operating rod and a pushing rod.

Since the tilting arm has the bulged portion facing up in order to arrange the connecting pin in this manner, the swinging arm itself is likely to increase in size towards the cylinder head cover side in the axial linear direction of the cylinder. In addition, in order to arrange the transmission rod, it sometimes has a domed portion that bulges to a position above the upper end face of the cylinder head. Therefore, the cylinder head and cylinder head cover also increase in size.

In addition, the transmission rod serving as a pressure force transmission element is placed on a coupling face between the cylinder head and the cylinder head cover on top of the swing arm axis. Therefore, also the solenoid serving as a source of pressure force generation is arranged on the cylinder head cover side in the axial linear direction of the cylinder. Accordingly, there is a possibility that the cylinder head and the cylinder head cover may increase more in size in the axial linear direction of the cylinder.

The present invention has been carried out in the situation described above, and another object of the present invention resides in the provision of a variable valve apparatus for an internal combustion engine of the OHC type where the increase in the size of a cylinder head can be avoided. cylinder and a cylinder head cover. For this, a connecting pin and a pressure force transmission element are arranged as close as possible to a crankcase side in the axial linear direction of the cylinder.

[Means to solve the problem]

The object of the present invention is achieved with the subject of the independent claim. The dependent claims better study the central idea of the present invention.

In order to achieve the object described above, a vehicle of the astride type includes, supported for tilting movement in a vehicle frame, a power unit (20) including an internal combustion engine of the OHC type (30) and a transmission of continuous variation of the belt type (21). The internal combustion engine of the OHC type (30) has an axial cylinder line (Cc) tilted to a large extent and provided with a plurality of tilting arms (57, 58) arranged and supported for tilting movement in a mutually contiguous relationship on a tilting arm axis (55) and operable in an interlocking relationship with motor valves (61, 62). A connecting pin (71) is mounted for movement in an axial direction of the tilting arm axis (55) in the tilting arms (57, 58) positioned adjacent to each other that are arranged so that they are movable between a connecting position wherein the connecting pin (71) connects the swingarms (57, 58) positioned adjacent to each other for integral swinging and a disconnecting position in which the connecting pin (71) disconnects the swinging arms (57, 58) from one another to allow independent swinging of each of the swinging arms

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(57, 58). A pressure force transmission element (74, 76) is provided which transmits pressure force from a source of pressure force generation (75) disposed outside the internal combustion engine of type OHC (30) to the connecting pin (71) to move the connecting pin (71) in the vehicle width direction. The internal combustion engine of the OHC type (30) has side walls (100L, 100R) directed in the vehicle width direction and side walls (100U, 100S) directed in the vertical direction, the side walls assuming a rectangular shape together tubular. The source of pressure force generation (75) is mounted on one of the side walls (100L, 100R) directed in the width-wide direction of the vehicle, and part of the vehicle frame is arranged on an outer side of the source of pressure force generation (75) in the vehicle width direction. The vehicle frame includes a front tube (2), a down tube (3) that extends down the front tube (2), and a pair of left and right floor tubes (4) that extend backward under a floor section (1c), which is arranged between a front section of the vehicle body (1f) and a rear section of the vehicle body (1r), of the descending tube (3), which rises obliquely upwards in a rear portion of the floor section (1c) and extending backwards. The source of pressure force generation (75) is located forward of the rear portions of the floor pipes (4) that rise obliquely upward and extend backward, as seen in side view, where the rear section of Vehicle body (1st) including the source of pressure force generation (75) is covered by the left and right sides with a body cover (29e).

In addition, a variable valve apparatus is provided for an internal combustion engine of the OHC type which includes a crankcase (31), a cylinder block (32) and a cylinder head (33) placed in order in the crankcase (31) and jointly fixed by a plurality of captive screws (180) extending through the cylinder block (32) and the cylinder head (33) in a linear axial cylinder direction, a plurality of tilting arms (57, 58) arranged and supported for tilting movement in a contiguous mutual relationship on a tilting arm axis (55) inside the cylinder head (33) and operable in an interlocking relationship with motor valves (61, 62), and a cylinder head cover (34) placed in the cylinder head (33) to cover the cylinder head (33), including the variable valve apparatus:

a connecting pin (71) mounted for movement in an axial direction of the tilting arm axis (55) in the tilting arms (57, 58) positioned adjacent to each other and movable between a connecting position in which the connecting pin (71) connects the swingarms (57, 58) positioned adjacent to each other for integral swinging motion and a disconnecting position in which the connecting pin (71) disconnects the swinging arms (57, 58) from one another to allow the independent tilting movement of each of the tilting arms (57, 58); Y

a pressure force transmission element (74, 76) configured to transmit pressure force from a source of pressure force generation (75) disposed outside the cylinder head (33) to the connecting pin (71) to move the connecting pin (71);

the source of pressure force generation (75) being mounted on a wall face (100L) of the cylinder head (33) in which a spark plug (49) is arranged protruding;

a housing box (77, 78) being arranged that houses a main body of the pressure force generating source (75) in a position where the housing box (77, 78) does not overlap with an axial line central spark plug (Cs), which is directed by the spark plug (49), as seen in the axial linear direction of the cylinder.

The variable valve apparatus for an internal combustion engine of the OHC type may also be configured such that

The source of pressure force generation (75) is placed on the cylinder head cover side (34) with respect to the spark plug (49).

The variable valve apparatus for an internal combustion engine of the OHC type may also be configured such that

The pressure force transmission element (74, 76) is provided for sliding movement in the cylinder head (33).

The variable valve apparatus for an internal combustion engine of the OHC type may be further configured such that the source of pressure force generation (75) has a plurality of mounting arm portions (77pr, 77qr, 77rr) formed around the housing (77, 78) so that they extend radially along the wall face (100L) of the cylinder head (33), and

The mounting arm portions (77pr, 77qr, 77rr) are mounted only on the cylinder head (33).

The variable valve apparatus for an OHC type internal combustion engine may be configured in addition to

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such that,

between the mounting arm portions (77pr, 77qr, 77rr), the mounting arm portion (77pr) that extends in a direction that overlaps the central axial line of spark plug (Cs) as seen in the axial linear direction of the cylinder has a recessed portion (77d) formed on top so that it opens towards the spark plug side (49) such that the recessed portion (77d) crosses, but stays away from, the line Axial central spark plug (Cs).

The variable valve apparatus for an internal combustion engine of the OHC type may also be configured such that,

in the cylinder head (33), nerve portions (103pr, 103qr, 103rr) with which the mounting arm portions (77pr, 77qr, 77rr) extending from the periphery of the housing (77, 78 ) are in contact, and portions of mounting boss (103p, 103q, 103r) at end portions of the nerve portions (103pr, 103qr, 103rr) are formed protruding, and the mounting arm portions (77pr, 77qr, 77rr) are mounted on the mounting boss portions (103p, 103q, 103r).

The variable valve apparatus for an internal combustion engine of type such that

The housing (77, 78) and the mounting arm portions (77pr, pressure force (75) are made of a metal.

The variable valve apparatus for an internal combustion engine of type such that,

on the wall face (100L) on which the source of pressure force generation (75) of the cylinder head (33) is mounted, an oil passage (133) is formed near the source of force generation pressure (75).

The variable valve apparatus for an internal combustion engine of the OHC type may also be configured such that

the internal combustion engine of the OHC type (30) is mounted on a vehicle frame of a straddle type vehicle (1) in a position where an axial cylinder line (Cc) swings forward in large measured at a position close to a horizontal position,

the source of pressure force generation (75) is mounted on the side wall face (100L) of the cylinder head (33) directed in the vehicle width direction, and

The source of pressure force generation (75) is covered on its outer sides in the width-wide direction of the vehicle with a part (6) of the vehicle frame.

The variable valve apparatus for an internal combustion engine of the OHC type may also be configured such that

a water pump (150) is mounted on a side wall face (100R) of the cylinder head (33) on the side opposite the side wall face (100L) on which the power generating source is mounted pressure (75).

The variable valve apparatus for an internal combustion engine of the OHC type may also be configured such that

the water pump (150) is arranged on the crankcase side with respect to the source of pressure force generation (75) in the axial linear direction of the cylinder,

a vent chamber (34b) is disposed on the inner side of the cylinder head cover (34), and

an outlet portion (34c) of the breather chamber (34b) is formed on an outer wall face of the cylinder head cover (34) such that its opening is directed to the water pump side (150) in the vehicle width direction.

A variable valve apparatus can also be provided for an OHC type internal combustion engine that includes a crankcase (31), a cylinder block (32) and a cylinder head (33) arranged in order in the crankcase (31) and fixed together by a plurality of captive screws (180) extending through the cylinder block (32) and the cylinder head (33) in a linear axial cylinder direction,

OHC may be configured in addition to 77qr, 77rr) of the OHC generation source may be configured in addition to

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a plurality of tilting arms (57, 58) arranged and supported for tilting movement in a mutually contiguous relation on a tilting arm axis (55) inside the cylinder head (33) and operable in an interlocking relationship with valves of engine (61, 62), and a cylinder head cover (34) placed in the cylinder head (33) to cover the cylinder head (33), including the variable valve apparatus:

a connecting pin (71) mounted for movement in an axial direction of the tilting arm axis (55) in the tilting arms (57, 58) positioned adjacent to each other and movable between a connecting position in which the connecting pin (71) connects the swingarms (57, 58) positioned adjacent to each other for integral swinging motion and a disconnecting position in which the connecting pin (71) disconnects the swinging arms (57, 58) from one another to allow the independent tilting movement of each of the tilting arms (57, 58); Y

a push rod (74) interposed between an operating rod (76) of a source of pressure force generation (75) disposed outside the cylinder head (33) and the connecting pin (71) and configured to transmit force of pressure from the operating rod (76) to the connecting pin (71) to move the connecting pin (71);

a rod sliding hole (102) forming in the cylinder head (33) in which the operating rod (76) and the pushing rod (74) are coaxially mounted for sliding movement in an axial rod direction, further forming in the cylinder head (33) an oil supply hole (130) that opens at its end to the interior of the cylinder head (33) and at its other end to the rod sliding hole (102) and supplies oil through it;

forming the oil supply hole (130) that supplies oil to an interleaved interior space (80) defined by and between the operating rod (76) and the pushing rod (74) in the rod sliding hole (102) when The source of pressure force generation (75) is in an inactive state, in a position offset in the axial direction of the rod relative to the interleaved interior space (80).

The variable valve apparatus for an internal combustion engine of the OHC type described above may be configured such that

The oil supply hole (130) is arranged so that only one of the push rod (74) and the operating rod (76) look at the oil supply hole (130) when the source of pressure force generation ( 75) is in an inactive state.

The variable valve apparatus for an internal combustion engine of the OHC type described above may be configured such that

part of the interleaved interior space (80) is in communication with the oil supply hole (130) when the source of pressure force generation (75) is in an inactive state.

The variable valve apparatus for an internal combustion engine of the OHC type described above may be configured such that

The oil supply hole (130) and the rod sliding hole (102) have a positional relationship such that their central axial lines intersect with each other at a right angle and in a spaced apart relationship.

The variable valve apparatus for an internal combustion engine of the OHC type described above may be configured such that

captive screw retaining holes (115, 116, 125, 126) are formed in the cylinder head (33) such that the captive screws (180) extend therethrough,

reinforcing plates (140, 141) that rest on an opening end face of at least two of the captive screw clamping holes (115, 116, 125, 126) are fixed together with the cylinder head (33) by the captive screws (180), and

part of the opening of the oil supply hole (130) on one end side is covered with the reinforcing plates (140, 141) as seen in the axial cylinder direction.

The variable valve apparatus for an internal combustion engine of the OHC type described above may be configured such that

the internal combustion engine of the OHC type (30) is mounted on a straddle type vehicle (1) in a position where its axial cylinder line (Cc) is tilted forward greatly to a nearby position to a horizontal position, and

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a nut (181) is screwed into the captive threads (180) and the oil supply hole (130) is placed on top and tightened so that an angular portion thereof is directed downwards.

The variable valve apparatus for an internal combustion engine of the OHC type described above may be configured such that

The oil supply hole (130) is arranged so that the interleaved interior space (80) when the source of pressure force generation (75) is in an inactive state is placed in a position where the interleaved interior space (80) Do not look at the oil supply hole (130).

A variable valve apparatus can also be provided for an OHC type internal combustion engine that includes a crankcase (31), a cylinder block (32) and a cylinder head (33) arranged in order in the crankcase (31) and jointly fixed by a plurality of captive screws (180) extending through the cylinder block (32) and the cylinder head (33) in a linear axial cylinder direction, a plurality of tilting arms (57, 58) arranged and supported for tilting movement in a contiguous mutual relationship on a tilting arm axis (55) inside the cylinder head (33) and operable in an interlocking relationship with motor valves (61, 62), and a cylinder head cover (34) placed on the cylinder head (33) to cover the cylinder head

(33), including the variable valve apparatus:

a connecting pin (71) mounted for movement in an axial direction of the tilting arm axis (55) in the tilting arms (57, 58) positioned adjacent to each other and movable between a connecting position in which the connecting pin (71) connects the swingarms (57, 58) positioned adjacent to each other for integral swinging motion and a disconnecting position in which the connecting pin (71) disconnects the swinging arms (57, 58) from one another to allow the independent tilting movement of each of the tilting arms (57, 58); Y

a pressure force transmission element (74, 76) configured to transmit pressure force from a source of pressure force generation (75) disposed outside the cylinder head (33) to the connecting pin (71) to move the connecting pin (71);

the connecting pin (71) being arranged between introduction holes of the tilting arm axis (57h, 58h) into which the tilting arm axis (55) is inserted for the tilting arms (57, 58) and end portions of drive side (57vv, 58vv) acting on the motor valves (61.62);

forming in the cylinder head (33) a plurality of captive screw clamping holes (115, 116, 125, 126) through which the captive screws (180) extend and forming in it shaft support holes of tilt arm (112h, 122h) supporting the tilt arm shaft (55), further forming in the cylinder head (33) a sliding hole of pressure force transmission element (102) into which the element is inserted of pressure force transmission (74, 76) for sliding movement, the sliding hole of the pressure force transmission element (102) being arranged in a position where the sliding hole of the pressure force transmission element (102) overlaps the tilting arm shaft support hole (122h) in the axial linear direction of cylinder between the captive screw clamping hole (125) located closest to the axle support hole of rocker arm (122 h) and the rocker arm shaft support hole (122h).

The variable valve apparatus for an internal combustion engine of the OHC type also described above may be configured such that

adjusting screws (57t, 58t) to adjust a support position with the motor valves (61, 62) are screwed into the end portions of the drive side (57vv, 58vv) of the swingarms (57, 58), Y

an axial line (Cp) of the connecting pin (71) is disposed between end portions of cylinder head side (57tt, 58tt) of the adjusting screws (57t, 58t) and an axial line (Cr) of the insertion holes of tilting arm axis (57h, 58h) in the axial linear direction of the cylinder.

The variable valve apparatus for an internal combustion engine of the OHC type also described above may be configured such that

the connecting pin (71) and the pressure force transmission element (74, 76) are arranged on the crankcase side (31) with respect to the coupling face (100t) between the cylinder head (33) and cylinder head cover

(3. 4) .

The variable valve apparatus for an internal combustion engine of the OHC type also described above may be configured such that

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The pressure force transmission element (74, 76) is adjacent to one of the captive threads (180).

The variable valve apparatus for an internal combustion engine of the OHC type also described above may be configured such that

An axial line (Cd) of the pressure force transmission element (74, 76) is placed on the crankcase side (31) with respect to the axial line (Cp) of the connecting pin (71).

The variable valve apparatus for an internal combustion engine of the OHC type also described above may be configured such that

The axial line (Cd) of the pressure force transmission element (74, 76) is positioned on the axis side of the swing arm (55) with respect to the axial line (Cp) of the connecting pin (71).

The variable valve apparatus for an internal combustion engine of the OHC type also described above may be configured such that

The source of pressure force generation (75) is firmly fixed only to the cylinder head (33).

[Effects of the invention]

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the source of pressure force generation (75) is mounted on the wall face (100L) of the cylinder head (33) in which the spark plug (49) is arranged protruding. In addition, the housing box (77, 78) that houses the main body of the pressure force generating source (75) is placed in the position where the housing box (77, 78) does not overlap with the central axial line of spark plug (Cs), which is directed by the spark plug (49), as seen in the axial linear direction of cylinder. Therefore, the source of pressure force generation (75) can be arranged in the position where it does not constitute an obstacle when the spark plug (49) is moved for assembly or disassembly in the axial linear direction of the line Axial central spark plug (Cs) directed by the spark plug (49) without providing the source of pressure force (75) away from the spark plug (49). Therefore, at the same time that the miniaturization of the cylinder head (33) is achieved, the spark plug maintenance operation (49) can be carried out favorably.

With the variable valve apparatus for an OHC type internal combustion engine described above, the

source of pressure force generation (75) is placed on the cylinder head cover side (34) with respect to the

spark plug (49). Therefore, the maintenance space around the spark plug (49) can be easily secured.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the

Pressure force transmission element (74, 76) is intended for sliding movement in the cylinder head of

cylinder (33). Therefore, bulging of the source of pressure force generation (75), which provides pressure force to the pressure force transmission element (74, 76), next to the cylinder head cover (34) can be avoided . In addition, the size of the cylinder head (33) and the peripheral elements in the axial linear direction of the cylinder can be prevented from increasing.

Consequently, the variable valve apparatus may be suitable in particular for a vehicle of the astride type in which the miniaturization of the cylinder head (33) and the peripheral elements is demanded.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the source of pressure force generation (75) has the multiple mounting arm portions (77pr, 77qr, 77rr) formed around the housing of housing (77, 78) so that they extend radially along the wall face (100L) of the cylinder head (33). In addition, the mounting arm portions (77pr, 77qr, 77rr) are mounted only on the cylinder head (33). Therefore, it is possible to raise the stiffness of the cylinder head (33) and to better prevent the bulging of the source of pressure force (75) to the side of the cylinder head cover (34).

In addition, the electromagnetic solenoid (75) is mounted only on the cylinder head (33), but not on the cylinder head cover (34). Therefore, in maintaining the valve system in the cylinder head (33), the cylinder head cover (34) can be removed without removing the source of pressure force generation (75). Consequently, the maintenance operation of the valve system can be easily carried out.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, between the mounting arm portions (77pr, 77qr, 77rr), the mounting arm portion (77pr) extending in the direction that overlaps with the central axial line of spark plug (Cs) as seen in the axial linear direction of cylinder has the recessed portion (77d) formed above so that it opens towards the spark plug side of

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ignition (49) in such a way that the lowered portion (77d) crosses, but is kept away from, the central axial line of spark plug (Cs). Therefore, when the spark plug (49) is moved in the direction of the central axial spark plug line (Cs) to mount or remove the spark plug (49), the mounting arm portion (77pr) It is not an obstacle thanks to the lowered portion (77d). Consequently, a good maintenance operation of the spark plug (49) can be carried out favorably.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, in the cylinder head (33), the nerve portions (103pr, 103qr, 103rr) with which the mounting arm portions (77pr) support , 77qr, 77rr) extending from the periphery of the housing box (77, 78) and the mounting boss portions (103p, 103q, 103r) in the end portions of the nerve portions (103pr, 103qr, 103rr) are formed protruding, and the mounting arm portions (77pr, 77qr, 77rr) are mounted on the mounting boss portions (103p, 103q, 103r). Therefore, the source of pressure force generation (75) is stably retained in the cylinder head (33) by the nerve portions (103pr, 103qr, 103rr) and the mounting boss portions (103p, 103q, 103r).

In addition, the mounting arm portions (77pr, 77qr, 77rr) of the pressure force generating source (75) support and are mounted on the nerve portions (103pr, 103qr, 103rr) and the mounting boss portions (103p, 103q, 103r). Therefore, the nerve portions (103pr, 103qr, 103rr) and the mounting boss portions (103p, 103q, 103r) can be maintained in a state of high rigidity. Consequently, the source of pressure force generation (75) can be more firmly supported.

With the variable valve apparatus for an internal combustion engine of the OHC type described above 7, the housing (77, 78) and the mounting arm portions (77pr, 77qr, 77rr) of the power generation source of Pressure (75) are made of a metal. Therefore, the heat generated in the housing (77, 78) for the source of pressure force (75) can be transmitted from the mounting arm portions (77pr, 77qr, 77rr) to the portions of nerve (103pr, 103qr, 103rr). Consequently, the heat radiation efficiency of the source of pressure force generation (75) can be improved.

In addition, the nerve portions (103pr, 103qr, 103rr) and the mounting projection portions (103p, 103q, 103r) are formed by protruding on the wall face (100L) of the cylinder head (33). Therefore, the portions of the mounting arm portions (77pr, 77qr, 77rr) that support the nerve portions (103pr, 103qr, 103rr) and the protruding mounting portions (103p, 103q, 103r) of the support face cooperate with the cylinder head wall face (100L) to form the space between. When running wind enters the space, the mounting arm portions (77pr, 77qr, 77rr) can be cooled, and, consequently, the cooling effect can be increased.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, on the wall face (100L) on which the source of pressure force generation (75) of the cylinder head (33) is mounted , the oil passage (133) has formed near the source of pressure force generation (75). Therefore, the source of pressure force generation (75) can be effectively cooled by the oil flowing in the oil passage (133).

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the internal combustion engine of the OHC type (30) is mounted on the frame of the straddle type vehicle (1) in a position in the that the axial cylinder line (Cc) is tilted forward greatly to the position close to the horizontal position. In addition, the source of pressure force generation (75) is mounted on the side wall face (100L) of the cylinder head (33) directed in the width direction of the vehicle, and the source of force generation of Pressure (75) is covered on its outer sides in the width-wide direction of the vehicle with a part (6) of the vehicle frame. Therefore, the source of pressure force generation (75) is disposed between the cylinder head (33) and the vehicle frame (6). Consequently, the source of pressure force generation (75) can be effectively protected against an external factor by the cylinder head (33) and the vehicle frame (6).

With the variable valve apparatus for an OHC type internal combustion engine described above, the water pump (150) is mounted on the side wall face (100R) of the cylinder head (33) on the side opposite the side wall face (100L) on which the source of pressure force generation (75) is mounted. Therefore, the source of pressure force generation (75) and the water pump (150) which are heavy elements are mounted in a distributed manner on the opposite side wall faces (100L, 100R) directed in the direction width of the cylinder head vehicle (33) so that they do not interfere with each other. Consequently, the weight balance around the cylinder head (33) can be improved. In addition, also where both the source of pressure force generation (75) and the water pump (150) are mounted on the cylinder head (33), the spark plug maintenance operation (49) can be performed favorably.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the breather chamber (34b) is disposed on the inner side of the cylinder head cover (34). In addition, the outlet portion (34c) of the breather chamber (34b) has been formed on the outer wall face of the cylinder head cover

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(34) so that its opening is directed to the water pump side (150) in the vehicle width direction. Therefore, the breather hose (146) connected to the outlet portion (34c) of the breather chamber (34b) of the cylinder head cover (34) and which extends to the water pump side (150) does not interferes with the source of pressure force generation (75) on the opposite side. It is also possible to easily prevent the breather hose (146) from interfering with the water pump (150) arranged on the crankcase side (31) with respect to the source of pressure force generation (75).

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the oil supply hole (130) that supplies oil to the interleaved interior space (80) defined by and between the operating rod (76) and the rod of thrust (74) in the rod sliding hole (102) when the source of pressure force generation (75) is in an inactive state, has been formed in the offset position in the axial direction of the rod with respect to the space interleaved interior (80). Therefore, when the source of pressure force generation (75) is in an inactive state, the interleaved interior space (80) in the position where the oil supply hole (130) is deflected in the axial direction It can be done similar to a closed space. In addition, in an initial stage when the source of pressure force generation (75) becomes operative to initiate movement of the operating rod (76), the oil supplied to the interleaved interior space (80) having a state close to a space closed is less likely to exit through the oil supply hole (130). Therefore, the oil in the interleaved interior space (80) can improve the damping function as an oil buffer.

In addition, together with the movement of the operating rod (76), the interleaved interior space (80) also moves and the deviation of the oil supply hole (130) decreases. Therefore, the oil in the interleaved interior space (80) gradually flows out of the oil supply hole (130).

Accordingly, although the operating rod (76) rests soon on the push rod (74), since also the push rod (74) moves to said support, the impact produced by the support can be reduced to a very low level .

Furthermore, with the variable valve apparatus for an internal combustion engine of the OHC type described above, the oil supply hole (130) is arranged so that only one of the thrust rod (74) and the operating rod (76) Look at the oil supply hole (130) when the source of pressure force generation (75) is in an inactive state. Therefore, a communication hole in the boundary between the oil supply hole (130) and the stem sliding hole (102) is partially or completely closed with the push rod (74) or the operating stem (76 ). Consequently, the interleaved interior space (80) formed between the operating rod (76) and the push rod (74) in the rod sliding hole (102) can be made similar to a closed space. Therefore, the oil leakage from the interleaved interior space (80) at an initial stage when the source of pressure force generation (75) becomes operative, can be avoided by further improving the oil damping function.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, part of the interleaved interior space (80) is in communication with the oil supply hole (130) when the source of pressure force generation (75 ) is in an inactive state. Therefore, when the source of pressure force generation (75) is in an inactive state, oil can be supplied from the oil supply hole (130) to the interleaved interior space (80) to fill the interleaved interior space ( 80). In addition, since the connection hole connecting the interleaved interior space (80) and the oil supply hole (130) with each other is narrow, the interleaved interior space (80) can be maintained in a near state of a closed space. Consequently, the oil leakage from the interleaved interior space (80) at an initial stage when the source of pressure force generation (75) becomes operative can be avoided by ensuring a high oil damping function.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the oil supply hole (130) and the rod sliding hole (102) have a positional relationship such that their central axial lines intersect a with another at a right angle and in a spaced relationship with each other. Therefore, the communication hole in the boundary between the oil supply hole (130) and the rod sliding support (102) becomes narrower. In addition, the oil supply hole (130) deviates not only in the axial direction, but also in a direction perpendicular to the axial direction with respect to the interleaved interior space (80). Therefore, while the source of pressure force generation (75) becomes operative to initiate movement of the operating rod (76) until the end of the operating rod (76) passes through the oil supply hole (130) , the interleaved interior space (80) can be maintained in a state close to that of a closed state. Consequently, oil leakage from the interleaved interior space (80) can be avoided by better ensuring a high oil damping function.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the reinforcing plates (140, 141) resting on the open end face of at least two of the captive screw clamping holes (115, 116, 125, 126) are fixed together with the cylinder head (33) by the captive screws (180). Therefore, the rigidity of the cylinder head (33) can be kept high. In addition, part

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of the opening of the oil supply hole (130) is covered with the reinforcing plates (140, 141) as seen in the axial cylinder direction. Therefore, oil leakage from the interleaved interior space (80) is avoided when the pressure force generating source (75) operates, and, consequently, the oil damping function can be kept increasingly high.

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the internal combustion engine of the OHC type (30) is mounted on the straddle type vehicle (1) in the position where its Axial cylinder line (Cc) is tilted forward largely to a position close to a horizontal position. In addition, the nut (181) that is placed above the oil supply hole (130) is screwed into the captive screws (180) and tightened so that its angular portion is directed downwards. Therefore, the oil adhered to the nut (181) flows down the angular portion. Therefore, the oil is guided and easily enters the oil supply hole (130).

With the variable valve apparatus for an internal combustion engine of the OHC type described above, the oil supply hole (130) is arranged so that the interleaved interior space (80) when the source of pressure force generation (75 ) in an inactive state is placed in the position where the interleaved interior space (80) does not face the oil supply hole (130). Therefore, the interleaved interior space (80) when the source of pressure force generation (75) is in an inactive state is a closed space. In addition, the output of the oil from the interleaved interior space (80) at an initial stage when the source of pressure force generation (75) becomes operational is very low. Consequently, the high oil damping function can be effectively achieved.

In addition, when the state of the pressure force generating source (75) changes from an active state to an inactive state, the push rod (74) is removed together with the operating rod (76). Next, the interleaved interior space (80) between the push rod (74) and the operating rod (76) expands as it passes through the oil supply hole (130). Consequently, the oil can be aspirated from the oil supply hole (130) to the interleaved interior space (80) to easily fill the interleaved interior space (80) with the oil.

With the variable valve apparatus for an internal combustion engine of the OHC type also described above, the connecting pin (71) is arranged between the introduction holes of the swing arm shaft (57h, 58h) for the swing arms (57, 58) and the end portions of the drive side (57vv, 58vv) acting on the motor valves (61, 62). Therefore, the connecting pin (71) can be arranged not in a very bulging position next to the cylinder head cover (34) of the tilting arm axis (55), but in a position closer to the tilting arm axis ( 55) in the axial linear direction of the cylinder on the crankcase side (31). Therefore, there is no need to make the swing arms (57, 58) bulge to the side of the cylinder head cover (34) to increase their size. In addition, increasing the size of the cylinder head (33) and the cylinder head cover (34) can be avoided.

In addition, the sliding hole of the pressure force transmission element (102) has been formed in the cylinder head (33) in the position in which it overlaps with the pivot arm shaft support hole (122h) in the axial linear direction of the cylinder between the clamping screw clamping hole (125) and the tilting arm shaft support hole (122h). Therefore, the pressure force transmission element (74, 76) can be arranged compactly making use of the space between the clamping screw clamping hole (125) and the tilting arm shaft support hole (122h ). In addition, the pressure force transmission element (74, 76) is arranged in the position in which it overlaps the tilting arm axis (55) in the axial linear direction of the cylinder. Therefore, the cylinder head (33) can be miniaturized in the axial linear direction of the cylinder, and the increase in size of the cylinder head (33) and the cylinder head cover (34) can be better avoided.

Specifically, as an internal combustion engine of the OHC type to be incorporated into a vehicle of the astride type in which it is difficult to secure a space, the internal combustion engine of the OHC type of the present invention that prevents the increase in size of The cylinder head and associated elements can be properly applied.

With the variable valve apparatus for an internal combustion engine of the OHC type also described above, the adjusting screws (57t, 58t) for adjusting the support position with the engine valves (61, 62) are screwed into the portions of drive side end (57vv, 58vv) of the swingarms (57, 58). In addition, the axial line (Cp) of the connecting pin (71) is disposed between the end portions of the cylinder head side (57tt, 58tt) of the adjusting screws (57t, 58t) and the axial line (Cr) of the insertion holes of tilting arm axis (57h, 58h) in the axial linear direction of cylinder. Therefore, the rocker arm shaft (55), the connecting pin 71 and the adjustment screws (57t, 58t) can be juxtaposed in a substantially straight line. Accordingly, the valve side arm portions (57v, 58v) of the swing arms (57, 58) from the swing arm shaft insertion holes (57h, 58h) to the drive side end portions ( 57vv, 58vv) acting on the motor valves (61, 62) can be formed substantially in the form of a coating. Therefore, the swingarms (57, 58) can be miniaturized with high spatial efficiency.

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In addition, the portions of the rocker arms (57, 58) in which the connecting pin (71) is mounted for movement, are formed with an increased thickness the amount that the connecting pin (71) is mounted and supported. Therefore, the rigidity of the valve side arm portions (57v, 58v) from the swing arm shaft insertion holes (57h, 58h) to the drive side end portions (57vv, 58vv) which Acting on the motor valves (61, 62) can be increased.

With the variable valve apparatus for an internal combustion engine of the OHC type also described above, the connecting pin (71) and the pressure force transmission element (74, 76) are arranged on the crankcase side (31) with respect to the coupling face (100t) between the cylinder head (33) and the cylinder head cover (34). Therefore, when the rocker arm shaft (55), the connecting pin (71) and the adjustment screws (57t, 58t) are juxtaposed in a straight line, the adjustment screws (57t, 58t) are placed close of the coupling face (100t) between the cylinder head (33) and the cylinder head cover (34). Consequently, the adjustment operation of the adjustment screws (57t, 58t) can be easily carried out.

Especially, the connecting pin (71) and the pressure force transmission elements (74, 76) are placed on the crankcase side (31) with respect to the end portions of the cylinder head side (57tt, 58tt) of the adjustment screws (57t, 58t). Therefore, the adjustment operation with the adjustment screws (57t, 58t) can be carried out more easily.

With the variable valve apparatus for an internal combustion engine of the OHC type also described above, the pressure force transmission element (74, 76) is contiguous with one of the captive screws (180). Therefore, the clamping screw clamping hole (125) and the pressure force transmission element slide hole (102) of the cylinder head (33) can be placed as close as possible to the support hole of swing arm shaft (122h). Consequently, the miniaturization of the cylinder head (33) can be anticipated.

With the variable valve apparatus for an internal combustion engine of the OHC type also described above, the axial line (Cd) of the pressure force transmission element (74, 76) is placed on the crankcase side (31) with respect to to the axial line (Cp) of the connecting pin (71). Therefore, the source of pressure force generation (75) that pushes the pressure force transmission element (74, 76) can be arranged near the crankcase side (31). Consequently, the amount of bulging of the source of pressure force generation (75) next to the cylinder head cover (34) in the axial linear direction of the cylinder can be reduced.

With the variable valve apparatus for an internal combustion engine of the OHC type also described above, the axial line (Cd) of the pressure force transmission element (74, 76) is placed on the tilting arm shaft side (55 ) with respect to the axial line (Cp) of the connecting pin (71). Therefore, a configuration can be efficiently implemented where, while the pressure force transmission element (74, 76) prevents interference with the captive screws (180), it pushes the connecting pin (71).

With the variable valve apparatus for an internal combustion engine of the OHC type also described above, the source of pressure force generation (75) is fixedly fixed only to the cylinder head (33). Therefore, the shape of the coupling face between the cylinder head (33) and the cylinder head cover (34) can be simplified. In addition, since the need to fix the source of pressure force generation (75) to the cylinder head cover side (34) is eliminated, simplification of the cylinder head cover (34) can also be achieved.

[Brief description of the drawings]

Figure 1 is a general side elevation view of a scooter type motorcycle according to an embodiment of the present invention.

Figure 2 is a view as seen in a direction indicated with an arrow mark II of Figure 1.

Figure 3 is a general left side elevation view of a power unit.

Figure 4 is a right side elevation view of the power unit with part of an internal combustion engine omitted.

Figure 5 is a sectional view of the internal combustion engine (sectional view taken along the line V-V of Figure 3).

Figure 6 is a vertical sectional view of a cylinder head and peripheral elements thereof.

Figure 7 is a view of a cylinder head and a valve mechanism as seen in a direction of an axial line of a cylinder from a cylinder head side with the cylinder head cover removed.

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Figure 8 is a sectional view taken along the VIN-VIN line of Figures 6 and 7.

Figure 9 is a sectional view taken along line IX-IX of Figures 6 and 7.

Figure 10 is a partial sectional view of the cylinder head and a variable valve apparatus when an electromagnetic solenoid is inactive (sectional view taken along the line X-X of Figure 6).

Figure 11 is a partial sectional view of the electromagnetic solenoid in an active state.

Figure 12 is a partial sectional view of the cylinder head and the variable valve apparatus when the solenoid solenoid is inactive in a different example.

Figure 13 is a top plan view of the cylinder head.

Figure 14 is a left side elevation view of the cylinder head itself (seen as seen in

an address indicated with an arrow mark XIV of figure 13).

Figure 15 is a right side elevation view of the cylinder head itself (seen as seen in a direction indicated with an arrow mark XV of Figure 13).

Figure 16 is a sectional view taken along line XVI-XVI of Figure 13.

Figure 17 is a sectional view taken along line XVII-XVII of Figure 14.

Figure 18 is a sectional view taken along line XVIII-XVIII of Figures 13 and 17.

[Mode of implementing the invention]

An embodiment according to the present invention is described below with reference to the drawings.

Figure 1 is a side elevational view of a motorcycle type scooter 1 which is a vehicle of the type to ride

astride according to an embodiment to which the present invention is applied.

In the present specification, the forward, backward, left and right directions are determined with reference to the motorcycle vehicle 1.

A front section of the vehicle body 1f and a rear section of the vehicle body 1r are connected to each other by a ground section under 1c. In a vehicle frame that configures the skeleton of the vehicle body, a descending tube 3 extends down a front tube 2 of the front vehicle body section 1f. Two floor tubes 4 that branch to the left and right at a lower end of the down tube 3 are curved horizontally and extend backwards under the floor section 1c. The floor pipes 4 bend obliquely upwards in a rear position of the floor section 1c and rise and extend backwards. A pair of left and right main tubes 5 are supported in their front portion by rear ends of the floor pipes 4 and extend obliquely upwards to the rear. The left and right main tubes 5 are connected to each other at their rear ends.

A connecting tube 6 is firmly fixed in its opposite end portions and disposed protruding to / in rear portions of the floor pipes 4 that rise obliquely upwards. The connecting tube 6 is curved in the form of a channel in the forward direction.

The main tubes 5 are firmly fixed at their end to the left and right side portions of the connection tube 6 to connect the main tubes 5, floor tubes 4 and connection tube 6 to one another to be firmly mounted (see Figure 2).

A storage box 8 and a fuel tank 9 are supported back and forth by the main tubes 5, and a seat 10 is disposed on top of them.

In the front section of the vehicle body 1f a handlebar 11 for pivoting movement is supported on the front tube 2 and is arranged in an upper position. A front fork 12 extends downward, and a front wheel 13 is supported for rotation at a lower end of the front fork 12.

Brackets 7 are arranged protruding downwards in the rear portions that extend upwards from the floor pipes 4. A power unit 20 is connected and is supported for tilting movement in the supports 7 through an articulation element 16.

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The power unit 20 is, in its front portion, a four-cylinder single-cylinder, water-cooled internal combustion engine 30 and has a position in which an axial line of a cylinder is tilted forward to a large extent to a position substantially close to a horizontal position. A support bracket 18 projects forward of a lower end of a crankcase 31 of the internal combustion engine 30 and is connected in its end portion to the articulation element 16 through a pivot shaft 19.

The power unit 20 includes a continuous variation transmission of the belt type 21 which extends backwards of the internal combustion engine 30. A reduction mechanism 22 is arranged in a rear portion of the continuous variation transmission of the belt type 21 A rear wheel 14 is arranged on a rear wheel axle 14a which is an output power shaft of the reduction mechanism 22.

A support 20b is arranged upwards in a rear portion of the power unit 20 in which the reduction mechanism 22 is arranged. A support 5b is arranged protruding in a rear portion of the main tubes 5. A rear shock absorber 15 is interposed between support 20b and support 5b.

With reference to Figure 3 which is a side elevation view of the power unit 20, the internal combustion engine 30 includes a cylinder block 32, a cylinder head 33 and a cylinder head cover 34 placed in order substantially in front of the crankcase 31 and tilts forward greatly. In an upper portion of the power unit 20, an intake tube 23 extends from an upper portion of the cylinder head 33, which tilts to a large extent, of the internal combustion engine 30 and bends backwards. A throttle body 25 is placed on top of the cylinder block 32 and connected to the intake tube 23. An air filter 27 is connected to the throttle body 25 through a connection tube 26 and placed on top of the continuous variation transmission of the type belt 21.

It should be noted that an injector 24 is mounted on the intake tube 23 and injects fuel into an intake port.

Meanwhile, an exhaust pipe 28 extends downward from a lower portion of the cylinder head 33 and bends backwards. In addition, the exhaust pipe 28 extends backward in a right-hand condition until connected to a silencer (not shown) on the right side of the rear wheel 14.

The front vehicle body section 1f is covered in front and behind with a front cover 29a and a leg protector 29b, respectively, and is covered in a lower portion from the front to its left and right sides with a front cover lower 29c. The floor section 1c is covered with a side cover 29d and the rear body section of vehicle 1r is covered on the left and right sides with a body cover 29e.

Figure 5 is a sectional view of the internal combustion engine 30 of the front half of the power unit 20 (sectional view taken along the line V-V of Figure 3).

The internal combustion engine 30 includes a piston 36 that moves from front to back in a cylinder sleeve 38 of the cylinder block 32, and a crankshaft 35. The piston 36 and a wrist 35a of the crankshaft 35 are connected to each other by a connecting rod 37.

The crankcase 31 is configured from the left crankcase 31L and the right crankcase 31R divided to left and right, joined together. The right crankcase 31 R forms a half of the crankcase section. Meanwhile, the left crankcase 31 L forms, in its front portion, one half of the crankcase section and bulges back so that it also serves as a transmission case in which the continuous variation transmission of the type of transmission is housed. elongated belt 21 forward and backward.

The left crankcase (transmission case) 31L is covered on its left open face elongated forward and backward with a transmission case cover 40 and houses the continuously variable transmission of the belt type 21.

In the crankcase formed from the front portion of the left crankcase 31L and the right crankcase 31R joined together, the crankshaft 35 is supported for rotation by left and right main bearings 39. The crankshaft 35 has left and right extensions extending in a horizontal direction to the left and right. A centrifugal ballast 41 of the continuous variation transmission of the belt type 21 and a drive pulley 42a are arranged in the left extension of the crankshaft 35.

Referring to FIG. 3, the continuous variation transmission of the belt type 21 includes a V-belt 42c extending between and around the drive pulley 42a and a driven pulley 42b disposed on an input shaft 22a of the drive mechanism. 22 reduction to transmit power. The transmission ratio of the continuously variable transmission of the belt type 21 is automatically changed by a change in the winding diameter of the V-belt 42c in the drive pulley 42a by the centrifugal ballast 41 and a simultaneous change in the winding diameter on the driven pulley 42b to vary the speed continuously. It should be noted that the

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Centrifugal ballast 41 moves in response to the rotational speed of the motor.

An eccentric chain drive sprocket 43, etc., is mounted on the right extension of the crankshaft 35. An AC generator 44 is disposed on a right end portion of the right extension.

A plurality of radiator fans 45 have been formed on a right side face of an outer rotor 44r of the generator CA 44.

The outer periphery of the radiator fans 45 is generally surrounded by a shell 46. A radiator 47 is supported in the shell 46 closely on the right side of a radiator fan 45. The radiator 47 is covered with a radiator cover 48 With a rack.

The internal combustion engine 30 of the present invention adopts a four-valve system of the SOHC type. The cylinder block 32 and the cylinder head 33 are fixed to the crankcase 31 with four captive screws 180 extending therethrough in an axial linear direction of cylinder Cc (central axis of the cylinder bore). A valve mechanism 50 is disposed in the cylinder head 33 (see Figures 5 and 6).

It should be noted that the cylinder head cover 34 is positioned and covers a coupling face 100t of the cylinder head 33 with an elastic sealing element 185 interposed therebetween in such a way as to cover the valve mechanism 50.

An eccentric chain 51 extends between and around a camshaft 54 and the crankshaft 35 and carries out the power transmission to the valve mechanism 50 in the cylinder head cover 34. An eccentric chain chamber 52 for the eccentric chain 51 It is arranged in relation to communication with the right crankcase 31R, the cylinder block 32 and the cylinder head 33 (see Figure 5).

In particular, an driven eccentric chain sprocket 53 is mounted at a right end of the camshaft 54 directed in the horizontal direction to the left and to the right, and the eccentric drive chain sprocket 43 is mounted on the crankshaft 35. The eccentric chain 51 extends through the inside of the eccentric chain chamber 52 between and around the driven eccentric chain sprocket 53 and the eccentric drive chain sprocket 43.

Meanwhile, a spark plug 49 is inserted into the cylinder head 33 from the opposite side (left side) to the eccentric chain chamber 52 towards a combustion chamber 90 (see Figures 2 and 5).

With reference to Figures 6 and 10, two first and second left and right intake holes 91 and 92 extend upwardly from the combustion chamber 90 to which the upper face of the piston 36 of the cylinder head 33 looks, which it swings largely forward. The first and second intake holes 91 and 92 are joined together with each other in a single upward side intake hole 93. The upward side intake hole 93 is connected to the intake tube 23.

On the other hand, two first and second left and right exhaust ports 95 and 96 extend downward from the combustion chamber 90. The first and second exhaust ports 95 and 96 are joined together with each other in a single exhaust port. from the side located down 97. The side exhaust hole located down 97 is connected to the exhaust pipe 28.

Cylindrical valve guides 61g and 62g are integrally mounted with curved outer wall portions of the first and second intake ports 91 and 92 of the cylinder head 33, respectively. A first intake valve 61 and a second intake valve 62 are supported for sliding movement in the valve guides 61g and 62g and open and close openings of the first and second intake ports 91 and 92 facing the combustion chamber 90 respectively.

Meanwhile, valve guides 63g and 64g are integrally mounted with curved outer wall portions of the first and second exhaust ports 95 and 96 of the cylinder head 33, respectively. A first exhaust valve 63 and a second exhaust valve 64 are supported for sliding movement in the valve guides 63g and 64g and open and close openings of the first and second exhaust ports 95 and 96 facing the combustion chamber 90 respectively.

The first and second intake valves 61 and 62 and the first and second exhaust valves 63 and 64 are pushed up by valve springs 61s, 62s and 63s, 64s, respectively, so that they close the openings facing the chamber of combustion 90.

The valve mechanism 50 has the axial cylinder line Cc largely tilted forward to a position close to a horizontal position. Therefore, the first and second intake valves 61 and 62 that open and close the openings of the first and second intake ports 91 and 92 facing the combustion chamber 90, respectively, are disposed above the camshaft 54 Meanwhile, the valves of

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first and second exhaust 63 and 64 that open and close the openings of the first and second exhaust ports 95 and 96 facing the combustion chamber 90, respectively, are arranged under the camshaft 54.

As shown in FIG. 6, an intake swing arm shaft 55 and an exhaust swing arm shaft 56 are disposed in upper and lower oblique positions in front of the camshaft 54, respectively.

With reference to FIGS. 6 and 7, a first intake swing arm 57 and a second intake swing arm 58 are supported in an adjacent relationship to each other to the left and to the right for swinging movement on the intake swing arm axis. 55 on the upper side. Meanwhile, an exhaust rocker arm 59 is supported for swinging movement on the exhaust rocker arm shaft 56 on the lower side.

The first intake swing arm 57 has an eccentric side arm portion 57c extending downwardly from its pivoting support portion 57a and a roller 57r supported for rotation at a lower end of the eccentric side arm portion 57c . The first intake rocker arm 57 contacts rolling on its roller 57r with a first intake eccentric lobe 54i of the camshaft 54. The first intake rocker arm 57 also has a valve side arm portion 57v extending upwards of its pivoting support portion 57a and an adjustment screw 57t screwed into an action end 57vv which is an upper end portion of the valve side arm portion 57v. The first intake rocker arm 57 contacts its adjustment screw 57t with an upper end of a valve stem of the first intake valve 61 which is pushed up by the valve spring 61s.

The second intake swing arm 58 has an eccentric side arm portion 58c extending downwardly from its portion diverted to the left side from a pivoting support portion 58a along the first intake swing arm 57. The second arm Intake swingarm 58 also has a skate 58s formed in a lower portion of the eccentric side arm portion 58c. The second intake swing arm 58 slidably contacts on its skate 58s with a second intake eccentric lobe 54ii of the camshaft 54. The second intake swing arm 58 also has a valve side arm portion 58v extending towards above its pivoting support portion 58a and an adjustment screw 58t screwed into an action end portion 58vv which is an upper end portion of the valve side arm portion 58v. The second intake rocker arm 58 contacts its adjusting screw 58t with an upper end of a valve stem of the second intake valve 62 which is pushed up by the valve spring 62s.

The exhaust swing arm 59 supported for tilting movement in the exhaust swing arm axis 56 on the lower side has a cylindrical pivoting support portion 59a positioned below the first intake swing arm 57 and the second intake swing arm 58. The Exhaust swing arm 59 further has an eccentric side arm portion 59c extending upwardly from its portion deflected to the right side of the pivoting support portion 59a and a roller 59r supported for rotation at an upper end of the portion of eccentric side arm 59c. The exhaust rocker arm 59 contacts rolling on its roller 59r with an eccentric exhaust lobe 54e of the camshaft 54. The exhaust rocker arm 59 further has valve side arm portions 59v and 59vv that extend downward of the opposite left and right sides of its pivoting support portion 59a and adjusting screws 59t and 59tt screwed into lower ends of the valve side arm portions 59v and 59vv, respectively. The exhaust rocker arm 59 contacts its adjusting screws 59t and 59tt with an upper end of a valve stem of the first and second exhaust valves 63 and 64 which are pushed up by the valve springs 63s and 64s, respectively .

Referring to Figure 8, the first intake eccentric lobe 54i of the camshaft 54 moves, by its eccentric profile, the roller 57r of the first intake swing arm 57 forward at a predetermined rotational angle of the camshaft 54 tilting the first intake rocker arm 57. Accordingly, the adjustment screw 57t at the other end of the first intake rocker arm 57 pushes the first intake valve 61 against the valve spring 61s by opening the opening of the first intake port 91, which looks at the combustion chamber 90, in a predetermined time.

Likewise, the exhaust eccentric lobe 54e moves, by its eccentric profile, the roller 59r of the exhaust swing arm 59 forward at a predetermined rotational angle of the camshaft 54 by tilting the exhaust swing arm 59. Accordingly, the screws adjustment 59t and 59tt at the other end of the exhaust rocker arm 59 push the exhaust valves 63 and 64 against the valve springs 63s and 64s opening the openings of the first and second exhaust ports 95 and 96 facing the chamber of combustion 90 in a predetermined time, respectively.

However, if the second intake eccentric lobe 54ii has a substantially cylindrical outer peripheral face and the skate 58s at one end of the second intake swing arm 58 is in sliding contact with the second intake eccentric lobe 54ii, then the second intake swing arm 58 tilts little. Consequently, the second intake valve 62 is placed in an inactive state

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closed in which the opening of the second intake port 92 facing the combustion chamber 90 remains closed.

However, in order to avoid the appearance of fuel stagnation in the closed idle state of the valve, the second inlet eccentric lobe 54ii has a very small eccentric projection at its rotational angle identical to that of the first inlet eccentric lobe 54i so that the second intake valve 62 opens little.

Accordingly, the closed idle state of the valves in the present embodiment is not a completely closed idle state of the valve, but implies a very small amount of valve opening.

It should be noted that the second intake valve 62 is placed in a closed inactive state except when it is moved to the opening and closing at times identical to those of the first intake valve 61 when the second intake swing arm 58 is connected for movement integral swingarm to the first intake swing arm 57 by a variable valve apparatus 70.

Variable valve apparatus 70 is described below with reference to Figure 10.

It should be noted that Figure 10 is a partial sectional view of the cylinder head 33 and the variable valve apparatus 70 as seen in a direction of the axial cylinder line from the cylinder head cover side, and its relationship to the left and to the right is inverse to that represented in the figure.

Referring to FIG. 10, the first intake swing arm 57 and the second intake swing arm 58 extend through the introduction holes of the swing arm axis 57h and 58h formed in the axis of the intake swing arm 55 and are they support each other in the direction to the left and to the right for tilting movement in the axis of the intake swing arm 55. The first intake swing arm 57 and the second intake swing arm 58 have the side arm portions of valve 57v and 58v and a first guide hole 57gh and a second guide hole 58gh, respectively. The valve side arm portions 57v and 58v extend upwardly from their pivoting support portions 57a and 58a. The first guide hole 57gh and the second guide hole 58gh have been drilled in parallel to the intake swing arm axis 55 in the valve side arm portions 57v and 58v, respectively. The first guide hole 57gh and the second guide hole 58gh are formed as circular holes of equal diameter and connected in a contiguous state to the left and to the right and coaxially with each other when the first intake valve 61 and the second valve of admission 62 are in the closed state, respectively.

It should be noted that the first guide hole 57gh and the second guide hole 58gh have bottom walls 57g and 58g formed on the sides opposite their faces that communicate with each other and the bottom wall 57g of the first guide hole 57gh has a hole circulate in its center.

A connecting pin 71 is mounted for sliding movement in the axial direction to the left and to the right in the first guide hole 57gh. In the second guide hole 58gh, a bottom-shaped cylindrically shaped disconnect piston 72 is mounted for sliding movement in the axial direction to the left and to the right with a spring 73 interposed between the disconnect piston 72 and the bottom wall 58g .

The connecting pin 71 is configured from a main cylindrical body 71a completely mounted in the first guide hole 57gh and a rod portion 71b protruding from the center of a left end face of the main cylindrical body 71a and extending to through the hollow hole of the bottom wall 57g. When the first guide hole 57gh and the second guide hole 58gh are positioned contiguously in the direction to the left and to the right and coaxially with each other, the main cylindrical body 71a of the connecting pin 71 can be moved to the second 58gh guide hole until it covers both first and second 57gh and 58gh guide holes.

When the first intake valve 61 (and the second intake valve 62) is in a closed state and the first guide hole 57gh and the second guide hole 58gh are coaxial and contiguous to each other in the direction to the left and towards on the right, if no external force is applied to the rod portion 71b of the connecting pin 71, then the disconnecting piston 72 pushed by the spring 73 pushes the connecting pin 71 to the left (to the right in Figure 10) as seen in Figure 10. Consequently, the main cylindrical body 71a is completely mounted in the first guide hole 57gh and the right end face of the main cylindrical body 71a with which the disconnect piston 72 contacts is placed level with the right open end face of the first guide hole 57gh. Therefore, the first intake swing arm 57 and the second intake swing arm 58 can swing independently of each other.

However, if external force is applied to the rod portion 71b of the connecting pin 71 to push the connecting pin 71 to the right (to the left in Figure 11) as seen in Figure 11, then the pin of connection 71 pushes the disconnect piston 72 against the thrust force of the spring 73. Accordingly, the main cylindrical body 71a of the connecting pin 71 advances and fits into the second hole

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of guide 58gh. Therefore, the main cylindrical body 71a of the connecting pin 71 is positioned to cover both the first guide hole 57gh and the second guide hole 58gh. As a result, the first intake rocker arm 57 and the second intake rocker arm 58 are connected to each other by the connecting pin 71 and swing integrally with one another.

Then, if the external force applied to the connecting pin 71 disappears, then the disconnecting piston 72 pushes the connecting pin 71 to the left by the pushing force of the spring 73 so that the connecting pin 71 is placed in the first 57gh fled hole canceling the connection.

In this way, the first intake swing arm 57 and the second intake swing arm 58 are connected to each other by the advance (movement in the right direction) of the connecting pin 71 and integrally swing with each other. On the other hand, the connection between the first intake swing arm 57 and the second intake swing arm 58 is canceled by the retraction (movement in the left direction) of the connecting pin 71.

With reference to Figure 6 (and Figure 10), the axial line Cp of the connecting pin 71 is disposed between end portions of cylinder head side 57tt and 58tt of the adjusting screws 57t and 58t and the axial line Cr of the introduction holes of swing arm shaft 57h and 58h in the axial linear direction of the cylinder.

The cylinder head 33 tilted forward to a large extent includes a rectangular outer tubular peripheral wall 100 configured from four wall portions including a left side wall 100L, a right side wall 100R, a top wall 100U and a bottom wall 100S. The rod portion 71b of the connecting pin 71 protrudes to the left (in Figure 10, to the right), and the left side wall 100L of the outer peripheral wall 100 has a rod sliding hole 102 drilled in its portion a which opposes the rod portion 71b in such a way that it extends to the left and to the right therethrough. A push rod 74 is inserted for sliding movement in the rod sliding hole 102.

The push rod 74 has a disc portion 74a disposed at its right end and having an increased diameter. The push rod 74 is mounted in the rod slide hole 102 of the left side wall 100L from the right side (in Figure 10, the left side) while the disk portion 74a at its right end remains inside of the cylinder head 33. The push rod 74 has a left end placed inside the rod slide hole 102.

A right side face of the disc portion 74a at the right end of the push rod 74 is facing the stem portion 71b protruding to the right of the connecting pin 71 mounted in the first guide hole 57gh of the first swing arm of admission 57.

While the connecting pin 71 swings together with the first intake rocker arm 57, the disk portion 74a of the push rod 74 always has a sufficient area so that it is always in front of the rod portion 71b of the connecting pin 71 that swings within a range within which the connecting pin 71 can swing.

An electromagnetic solenoid 75 is mounted from the outer side to the left side wall 100L of the cylinder head 33 and serves as a source of pressure force generation to move the variable valve apparatus 70.

It should be noted that the source of pressure force generation can be configured by applying a hydraulic cylinder in addition to the electromagnetic solenoid 75.

As shown in Figures 10 and 11, an operating rod 76 protrudes to the right of the electromagnetic solenoid 75 and is inserted from the left side into the rod slide hole 102 in which the push rod 74 is inserted from the side straight. The left end of the push rod 74 and the right end of the operating rod 76 face each other inside the rod slide hole 102.

With reference to Figure 6 (and Figure 10), the axial line Cd of the pressure force transmission elements of the push rod 74 and the operating rod 76 inserted in the rod sliding hole 102 is always placed in the crankcase side 31 and on the axis side of the intake swing arm 55 with respect to the axial line Cp of the connecting pin 71 which is mounted for tilting movement in the first guide hole 57gh of the first intake swing arm 57.

Figure 10 is a partial sectional view of electromagnetic solenoid 75 in an inactive state. In the disconnected state in which the connecting pin 71 is pushed to the left through the disconnecting piston 72 by the pushing force of the spring 73 to accommodate the main cylindrical body 71a completely in the first guide hole 57gh, the push rod 74 assumes a left-hand position in which

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contacts the rod portion 71b of the connecting pin 71. In the rod slide hole 102, an interleaved interior space 80 of a suitable width is formed in interleaved relationship between the push rod 74 and the operating rod 76 when the solenoid Electromagnetic 75 is in an inactive state.

Figure 11 is a partial sectional view of electromagnetic solenoid 75 in an active state. By operation of the electromagnetic solenoid 75, the operating rod 76 protruding to the right pushes the connecting pin 71 to the right (in Figure 11, to the left) together with the disconnecting piston 72 against the thrust force of the spring 73. Accordingly, the main cylindrical body 71a of the connecting pin 71 encompasses both the first guide hole 57gh and the second guide hole 58gh to place the first intake swing arm 57 and the second intake swing arm 58 in a state of connection.

Cylinder head 33 is a cast piece configured from a non-magnetic element made of an aluminum alloy. The structure of the cylinder head 33 is described in detail with reference to Figures 13 to 18.

An opening of the upstream side intake hole 93 is formed in the upper wall 100U of the cylinder head 33, and an open end is formed in the bottom wall 100S such that it protrudes slightly outside the exhaust hole side down 97.

In addition, the spark plug 49 is mounted on the left side wall 100L of the cylinder head 33, and the electromagnetic solenoid 75 is mounted on the left side wall 100L as described above (see Figures 3 and 8).

Therefore, a spark plug mounting hole 101 is formed in a recessed central portion of the left side wall 100L of the cylinder head 33 such that the spark plug 49 is mounted obliquely as shown in the figure 14. In addition, the rod sliding hole 102 into which the operating rod 76 of the electromagnetic solenoid 75 and the pushing rod 74 are inserted, has been drilled in a position of the cylinder head 33 slightly displaced to the side of the wall upper 100u from the center near the coupling face 100t of the cylinder head 33 with the cylinder head cover 34.

A stem protrusion portion 102b has been formed in an outer lateral open portion of the stem slide hole 102 and has an inner portion of increased diameter 102a formed above such that the inner diameter of the stem slide hole 102 increases by two stages (see figure 17).

Referring to Figure 14, a portion of mounting boss 103p has been formed in the left side wall 100L of the cylinder head 33 and has a mounting hole in its position displaced to the side of bottom wall 100S from the center near 100t coupling face. In addition, a nerve portion 103pr has been formed so that it extends along the coupling face 100t from the stem boss portion 102b toward the mounting boss portion 103p.

The stem projection portion 102b is located on the upper wall side 100U with respect to the spark plug mounting hole 101, and the mounting projection portion 103p is located on the lower wall side 100S with respect to the bore hole. spark plug assembly 101. The nerve portion 103pr connecting the rod boss portion 102b and the mounting boss portion 103p to each other has been formed through the central spark plug mounting hole 101 on the side of 100t coupling face

A mounting boss portion 103q and a nerve portion 103qr are formed on the side opposite the mounting boss portion 103p with respect to the rod boss portion 102b. A mounting boss portion 103r has been formed at a fairly spaced position of the rod boss portion 102b on the side opposite the coupling face 100t. A nerve portion 103rr has been formed so that it extends from the stem boss portion 102b to the mounting boss portion 103r.

In particular, two portions of rib 103pr and 103qr extend from the rod boss portion 102b to opposite sides of each other along the coupling face 100t, and a portion of rib 103rr extends in a direction perpendicular to the 103pr and 103qr nerve portions. The mounting protrusion portions 103p, 103q and 103r are formed in end portions of the nerve portions 103pr and 103qr and the nerve portion 103rr, respectively.

The three portions of mounting boss 103p, 103q and 103r and the three nerve portions 103pr, 103qr and 103rr described above are bulged from an outer wall face of the left side wall 100L such that their end faces form a face assembly (portion indicated by shaded reticule lines in figure 14) of the same continuous plane.

Meanwhile, as shown in Fig. 10, the electromagnetic solenoid 75 includes a fixed core 75s and a mobile core 75d fixed integrally fixed to an end portion of the operating stem 76 which is

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extends through the fixed core 75s. The electromagnetic solenoid 75 includes a solenoid main body that includes the movable core 75d around which a coil 75c is circumferentially arranged. The main solenoid body is housed in housing boxes 77 and 78 formed as two divisional elements.

A spring 79 is interposed between the fixed core 75s and the mobile core 75d.

Housing boxes 77 and 78 are made of a metal with high thermal conductivity.

The housing box 77 is configured from a cylindrical portion 77a covering the periphery of the coil 75c, a bottom wall portion 77b for the cylindrical portion 77a, and three mounting arm portions 77pr, 77qr and 77rr extending radially from the bottom wall portion 77b. Portions of mounting boss 77p, 77q and 77r having mounting holes are formed in end portions of the mounting arm portions 77pr, 77qr and 77rr, respectively (see Figures 3 and 14).

A stem projection portion 77bb is disposed in the center of the bottom wall portion 77b and protrudes in and out. The rod protrusion portion 77bb supports the operating rod 76 for pivoting movement and for sliding movement. The portion of the stem projection portion 77bb protruding to the inner side configures the fixed core 75s.

The housing box 78 has a cylindrical bottom shape and is mounted at the open end of the cylindrical portion 77a of the housing box 77 such that it covers the moving core 75d.

It should be noted that an elastic element 78r is glued to the bottom face of the housing box 78 of the cylindrical shape with a bottom opposite the mobile core 75d.

The three mounting arm portions 77pr, 77qr and 77rr and the three mounting projection portions 77p, 77q and 77r extending radially from the bottom wall portion 77b of the housing box 77 correspond to the three nerve portions 103pr , 103qr and 103rr and the three mounting projection portions 103p, 103q and 103r of the left side wall 100L of the cylinder head 33, respectively, and face each other. Thus, the mounting boss portions 77p, 77q and 77r and the mounting arm portions 77pr, 77qr and 77rr contact the mounting face which is the same continuous face formed by the mounting boss portions 103p, 103q and 103r and the nerve portions 103pr, 103qr and 103rr. Then, its mounting boss portions are fixed to each other with bolts 104p, 104q and 104r to mount the electromagnetic solenoid 75 on the left side wall 100L of the cylinder head 33 (see Figures 3 and 14).

Then, the rod boss portion 77bb formed protruding in the center of the lower wall portion 77b of the housing box 77 is inserted into the portion of the increased inner diameter 102a of the rod slide hole 102 of the cylinder head 33 with a sealing element 83 and an elastic ring 84 interposed therebetween (see Figure 10).

The lower wall portion 77b and the mounting arm portions 77pr and 77qr of the housing case 77 of the electromagnetic solenoid 75 protrude to the side of the cylinder head cover 34 from a coupling face 104h of the cylinder head 33 with the cover of cylinder head 34 as indicated by a long line and two alternative shorts in figure 14 (see figures 8 and 14).

However, the electromagnetic solenoid 75 is mounted only on the cylinder head 33.

With reference to Figure 14, the electromagnetic solenoid 75 mounted on the cylinder head 33 in this manner is disposed in a position that is on the side of the cylinder head cover 34 with respect to the spark plug 49 and does not overlap with the central axial line of spark plug Cs directed by spark plug 49 as seen in the axial linear direction of cylinder shown in Figure 7.

The housing box 77 has a mounting arm portion 77qr that contacts the nerve portion 103pr formed through the spark plug mounting hole 101 in the center of the cylinder head 33 on the coupling face 100t. The mounting arm portion 77qr has a recessed portion 77d formed above and open towards the spark plug side 49 such that it extends through and stays away from the central axial line of spark plug Cs directed by the spark plug Ignition 49 mounted in the spark plug mounting hole 101 between the mounting boss portion 103p and the mounting arm portion 77rr (see Figures 3, 8 and 14).

When the power unit 20 is incorporated into the scooter type motorcycle 1, the electromagnetic solenoid 75 mounted on the left side wall 100L of the cylinder head 33 of the internal combustion engine 30 is covered, on the outer side (left side) in the width-wide direction of the vehicle and its front side, surrounding it with the connecting tube 6 of the vehicle frame.

The OHC 30 internal combustion engine of the present invention is an internal combustion engine

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water cooled, and a water pump 150 is mounted on the right side wall 100R of the cylinder head 33 on the side opposite the left side wall 100L on which the electromagnetic solenoid 75 is mounted.

A circular hole 105 of large diameter has been formed in the right side wall 100R of the cylinder head 33 (see Figure 15). A cylindrically shaped water pump body 151 of the water pump 150 is mounted waterproof in the circular hole 105 and is supported by it (see Figure 8).

With reference to FIG. 8, the water pump body 151 of the water pump 150 is configured from a long cylindrical portion 151a and a short cylindrical portion 151b. The long cylindrical portion 151a is elongated in an axial direction of a pump drive shaft 153 and supports the pump drive shaft 153 for rotation through a bearing 155. The short cylindrical portion 151b expands in a diametral and short direction in the axial direction. The short cylindrical portion 151b extends in a diametral direction at its open end so that it accommodates part of the impeller 154 mounted on the pump drive shaft 153. The long cylindrical portion 151a is mounted and fixed to the circular hole 105 of the side wall right 100R of the cylinder head 33 with an elastic ring 156 interposed therebetween such that the pump drive shaft 153 is coaxially arranged with the camshaft 54. The pump drive shaft 153 is directly mounted and coupled, in its left end, in already a mounting hole drilled in a right end face of the camshaft 54.

A water pump cover 152 covers a right opening of the short cylindrical portion 151b of the water pump body 151 and cooperates with the short cylindrical portion 151b to accommodate the impeller 154 therebetween. The water pump cover 152 is superimposed on the open end face of the short cylindrical portion 151b.

Four bolt holes are formed in an outer circumference of the short cylindrical portion 151b of the water pump body 151. Also in the water pump cover 152 four bolt holes corresponding to the bolt holes of the pump body have been formed. of water 151 (see Figures 4 and 15).

Three portions of mounting boss 106 having a threaded female hole are formed in the right side wall 100R of the cylinder head 33 and around the circular hole 105. Bolt holes in the three corresponding positions of the water pump body 151 and the water pump cover 152 contacts the three mounting projection portions 106 of the cylinder head 33 and are fixed together individually by the bolts 157a to mount the water pump 150 on the right side wall 100R of the cylinder head 33.

It should be noted that the bolt holes in the remaining position of the water pump body 151 and the water pump cover 152 protrude to the cylinder head cover side 34 of the coupling face 100t of the cylinder head 33 with the cylinder head cover 34. Cylinder head 33 and cylinder head cover 34 are fixed together with bolts 157b (see Figure 8).

Referring to Fig. 4, a portion of water suction pipe 152a extends from the inlet port bore on the right side of the pump drive shaft 153 along the side face to the water pump cover 152 right of the cylinder head 33 towards the cylinder block side 32. In addition, the discharge port directed in a tangential direction of the outer periphery of the impeller 154 extends such that a portion of water discharge tube 152b is extend to the water pump cover 152. In addition, an air vent tube portion 152c is arranged protruding upwardly in an upper portion of the outer periphery of the impeller 154.

A water outlet opening 107 of a water jacket 33w in the cylinder head 33 is formed in the right side wall 100R of the cylinder head 33. In addition, two working holes 108 and 109 have been drilled in the side wall right 100R along the coupling face 100t with the cylinder head cover 34 around the circular hole 105.

Working holes 108 and 109 are coaxially located with the intake swing arm shaft 55 and the exhaust swing arm shaft 56.

With reference to Figure 4, the portion of water suction tube 152a of the water pump 150 extending to the side of the cylinder block 32 is connected to a thermostat 160.

A bifurcated connection tube 161 is disposed protruding in the water outlet opening 107 of the cylinder head 33. The main tube of the bifurcated connection tube 161 is connected to a radiator reservoir upstream 47a of the radiator 47 a via a radiator inlet hose 162 while the branch tube of the branch connection tube 161 is connected to the thermostat 160 through a branch hose 164.

A downstream radiator reservoir 47b of radiator 47 and thermostat 160 are connected to each other.

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another by a radiator outlet hose 163.

A water discharge hose 165 connects to each other a water inlet opening of the water jacket in the cylinder block 32 and the water discharge tube portion 152b of the water pump 150.

It should be noted that the portion of the air vent tube 152c disposed protruding upwardly in the water pump 150 is connected to the upper branch connection tube 161 through an air vent tube 166.

Upon heating while the internal combustion engine 30 has not yet heated, the thermostat 160 closes the water path that enters the radiator 47, but opens the water path derived from the cylinder head 33 so that the heating is accelerated to through the water path that does not pass through the radiator 47. Then, when the heating reaches the end and normal operation starts, the thermostat 160 closes the water path for bypass of the cylinder head 33, but opens the path of water entering from the radiator 47. Accordingly, cooling water cooled by the radiator 47 circulates from the cylinder block 32 in the cylinder head 33 to cool the cylinder block 32 and the cylinder head 33.

The cylinder head 33 has an inner wall 110 formed parallel to the right side wall 100R on the inner side of the outer peripheral wall 100 (see Figures 9 and 13). The inner wall 110 cooperates with the right side wall 100R to configure the eccentric chain chamber 52 in between.

A circular bearing hole 111 is coaxially formed with the circular hole 105 in the inner wall 110 and has a diameter substantially equal to that of the circular hole 105 formed in the right side wall 100R. In addition, an intake rocker arm shaft support portion 112 and an exhaust rocker arm shaft support portion 113 are formed in the inner wall 110. The intake rocker arm shaft support portion 112 and the portion Exhaust arm swivel arm support 113 have an intake support arm swivel arm shaft 112h and an exhaust arm support arm swing arm 113h having a diameter equal to that of the working holes 108 and 109 formed on the right side wall 100R, respectively, and are coaxially arranged with them.

The working holes 108 and 109 for drilling the tilting arm shaft support holes 112h and 113h are closed on the outside with stopper elements 65 and 66, respectively (see Figures 7 and 9).

When the water pump 150 is mounted on the right side wall 100R of the cylinder head 33, the short cylindrical portion 151b of the water pump body 151 is placed next to the plug elements 65 and 66 and covers them on the outside ( see figures 4 and 7).

Accordingly, the exit of the plug elements 65 and 66 is avoided by the water pump 150 mounted on the cylinder head 33.

Captive screw retaining holes 115 and 116 are perforated on opposite outer sides of the intake swing arm shaft support portion 112 and the exhaust swing arm shaft support portion 113 of the inner wall 110, respectively, such that they extend through the inner wall 110 in the axial linear direction of the cylinder (see Figures 13 and 16).

The captive screws 180 are mounted in the captive screw fastening holes 115 and 116.

The left side wall 100L is recessed to the inner side of the coupling face 100t with the cylinder head cover 34 and faces the inner wall 110. A circular support hole 121 of a diameter smaller than that of the circular bearing hole 111 of the inner wall 110 is coaxially formed with the circular bearing hole 111. An intake arm of the tilting arm axis 122 and a support portion of the axis of the swing arm 123 are formed in the left side wall 100L. The intake rocker arm shaft support portion 122 and the exhaust rocker arm shaft support portion 123 have an intake rocker arm shaft support hole 122h and an exhaust rocker arm shaft support hole 123h, respectively. The intake rocker arm shaft support hole 122h and the exhaust rocker arm shaft support hole 123h have an equal diameter and are coaxially arranged in opposite relation to the intake rocker arm shaft support hole 112h and the Exhaust arm pivot arm shaft support hole 113h of inner wall 110, respectively.

The intake rocker arm shaft support portion 122 and the exhaust rocker arm shaft support portion 123 have captive screw retaining holes 125 and 126 drilled in a position rather offset to the left on their outer sides and which extends in the axial direction of the cylinder through it (see Figures 13 and 14).

The captive screws 180 are inserted in the captive screw retaining holes 125 and 126.

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The stem sliding hole 102 has been formed between the intake rocker arm shaft support hole 122h of the left side wall 100L and the captive thyme holding hole 125 near the intake rocker arm shaft support hole 122h In particular, the rod sliding hole 102 has been formed in a position that overlaps the intake support of the inlet tilting arm axis 122h in the axial linear direction of the cylinder (see Figures 13, 17 and 18).

The stem sliding hole 102 overlaps with a nut 181 as seen in the axial linear direction of the cylinder and is disposed near the clamping screw holding hole 125.

In addition, an oil supply hole 130 has been drilled in the axial linear direction of the cylinder toward the rod slide hole 102 near the clamping screw holding hole 125 and opens to the end face of the left side wall 100L on the cylinder head cover side 34.

The oil supply hole 130 and the rod slide hole 102 have a positional relationship such that their central axial lines are spaced from each other and intersect perpendicularly with each other.

Accordingly, the oil supply hole 130 communicates the inner side space of the cylinder head 33 and the rod sliding hole 102 with each other.

The camshaft 54 is supported for rotation in the circular bearing hole 111 and the circular support hole 121 arranged coaxially with one another in the inner wall 110 and the left side wall 100L facing each other.

Referring to Figure 8, the camshaft 54 is mounted at its left end for rotation in the circular support hole 121 and at its right side portion for rotation in the circular bearing hole 111 through a bearing 82.

It should be noted that the camshaft 54 protrudes from the eccentric chain chamber 52 on the right side with respect to the bearing 82 and has the driven eccentric chain sprocket 53 mounted at its right end.

In addition, a decompression mechanism 85 is incorporated between the bearing 82 and the exhaust eccentric lobe 54e of the camshaft 54 on the left side of the bearing 82 using the exhaust eccentric lobe 54e.

The intake rocker arm shaft 55 is mounted at its opposite ends in the intake rocker arm shaft support hole 112h and the intake rocker arm shaft support hole 122h, which are coaxial with each other, of the inner wall 110 and the left side wall 100L that are opposite each other in such a way that the intake rocker arm shaft 55 is supported in the support holes 112h and 122h, respectively (see Figures 7 and 9). In addition, the exhaust rocker arm shaft 56 is mounted at its opposite ends in the exhaust rocker arm shaft support hole 113h and the exhaust rocker arm shaft support hole 123h, which are coaxial with each other, of the inner wall 110 and the left side wall 100L such that the exhaust rocker arm shaft 56 is supported in the holes 113h and 123h, respectively (see Figures 7 and 8).

The intake rocker arm shaft support portion 112, the exhaust rocker arm shaft support portion 113 and the open end portions of the captive screw retaining holes 115 and 116 of the inner wall 110 and the portion of the intake rocker arm shaft support 122, the exhaust rocker arm shaft support portion 123 and the open end portions of the clamping screw retaining holes 125 and 126 of the left side wall 100L have a face of end (portions indicated by shaded reticule lines in Figure 13) which is in the same plane as a coupling face 104t of the cylinder head 33 with the cylinder head cover 34.

Referring to Figure 13, a pin insertion hole 112p of a small diameter has been formed such that it extends in the axial linear direction of the cylinder through a portion of the intake arm support arm of the tilting arm. 112 of the inner wall 110 from its end face to the intake shaft support arm of the tilting arm 112h.

On the intake rocker arm shaft 55 mounted in the intake rocker arm shaft support hole 112h, a pin insertion hole 55p has been drilled so that it extends through the intake rocker arm shaft 55 along the axial center in a diametral direction in a relation corresponding to the pin insertion hole 112p. The pin insertion holes 112p and 55p are coaxially formed in the support arm of the intake rocker arm 112 and the intake rocker arm shaft 55, respectively. A pin element 142 has been inserted into the pin insertion holes 112p and 55p from the cylinder head cover side 34 to secure the intake rocker arm shaft 55 to the intake rocker arm shaft support portion 112 ( see figure 9).

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A pin insertion hole 123p of a small diameter has been formed so that it extends in the axial direction of the cylinder through a portion of the exhaust rocker arm shaft support portion 123 of the left side wall 100L from its end face to the 123h exhaust swing arm axle support hole.

A pin insertion hole 56p has been drilled so that it extends through the exhaust rocker arm shaft 56, which is inserted into the exhaust rocker arm shaft support hole 123h, along the axial center in a diametral direction in a relation corresponding to the pin insertion hole 123p. A pin element 143 has been inserted from the cylinder head cover side 34 to the pin insertion holes 123p and 56p coaxially formed in both the exhaust rocker arm shaft support portion 123 and the rocker arm axis of Exhaust 56 to fix the exhaust rocker arm shaft 56 to the exhaust rocker arm shaft support portion 123 (see Figure 8).

It should be noted that a working hole 127 has been formed so that it extends in the axial linear direction of the cylinder through a portion of the support arm of the inlet swing arm 122 of the left side wall 100L from its end face to the intake hole of the tilting arm of the intake arm 122h.

A reinforcing plate 140 bridges the open end portions of the clamping screw retaining holes 115 and 116 of the inner wall 110 (see Figure 7).

The reinforcing plate 140 contacts end faces of the open end portions of the clamping screw retaining holes 115 and 116 and end faces of the intake arm swivel arm support portion 112 and the support portion of rocker arm axis 113. The opposite end portions of the reinforcing plate 140 are fixed together with the cylinder head 33 with the captive screws 180.

The reinforcing plate 140 is curved and extends, in a central portion of a side edge between its opposite end portions on the eccentric chain chamber side 52 (left side), to the side of circular bearing hole 111 to form a portion of curved sheet 140b (see Figures 8 and 9).

As shown in Figure 6, the curved sheet portion 140b has a width substantially equal to the distance between the central axes of the intake swing arm shaft support hole 112h and the exhaust swing arm shaft support hole 113h. The curved sheet portion 140b partially blocks the openings of the intake rocker arm shaft support hole 112h and the exhaust rocker arm shaft support hole 113h. Meanwhile, an end portion of the curved sheet portion 140b that has been arcuately lowered partially blocks the opening of the circular bearing hole 111.

Accordingly, as shown in FIGS. 6 and 8, the reinforcing plate 140 prevents, by its portion of curved plate 140b, that the outer race of the bearing 82, which supports the camshaft 54 for rotation, leaves the bore hole. circular bearing 111 thereby preventing the camshaft 54 from moving in the axial direction.

Simultaneously, as shown in Figures 6 and 9, the curved sheet portion 140b of the reinforcing plate 140 prevents the intake rocker arm shaft 55 and the exhaust rocker arm shaft 56 from leaving the support hole of intake rocker arm shaft 112h and the exhaust rocker arm shaft support hole 113h, respectively. Consequently, the intake rocker arm shaft 55 and the exhaust rocker arm shaft 56 are prevented from moving in the axial direction.

In addition, the reinforcing plate 140 has a pin insertion hole 140p drilled in a position of the cylinder head 33 corresponding to the pin insertion hole 112p formed in the intake arm support arm of the tilting arm 112. The hole Pin insert 140p has been coaxially drilled with pin insert hole 112p.

On the other hand, a reinforcing plate 141 bridges the open end portions of the clamping screw retaining holes 125 and 126 of the left side wall 100L.

The reinforcing plate 141 contacts end faces of the open end portions of the clamping screw retaining holes 125 and 126 and end faces of the intake arm of the tilting arm axis 122 and the support portion of rocker arm shaft 123. The opposite end portions of the reinforcing plate 141 are fixed together with the cylinder head 33 with the captive screws 180.

The reinforcing plate 141 has a recessed portion 141p formed so as to stay away from the pin insertion hole 123p of the exhaust rocker arm shaft support portion 123 (see Figure 7).

In addition, the reinforcing plate 141 closes the working hole 127 of the intake rocker arm shaft support portion 122 and partially covers the opening of the oil supply hole 130 as is

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represented in figure 7.

The reinforcing plate 140 that bridges the open end portions of the captive thyme holding holes 115 and 116 of the inner wall 110 is fixed at their opposite ends together with the cylinder head 33 by the captive screws 180 and bridges the portions open end of the clamping screw retaining holes 125 and 126 of the left side wall 100L. However, since the reinforcing plate 140 is fixed at its opposite ends together with the cylinder head 33 by the captive screws 180, the cylinder head 33 can be maintained in a state of high rigidity.

It should be noted that the pin element 142 mounted in the pin insertion holes 112p and 55p of both the intake rocker arm shaft support portion 112 and the intake rocker arm shaft 55 extends through the hole of inserting pin 140p of the reinforcing plate 140 so that its end portions protrude (see Figure 9).

In addition, the pin member 143 mounted in the pin insertion holes 123p and 56p of both the exhaust swing arm shaft support portion 123 and the exhaust swing arm shaft 56 extends through the recessed portion 141p of the reinforcing plate 141 in such a way that its end portions protrude (see Figure 9).

The cylinder head cover 34 has bulged a large amount in its central portion to form a domed portion 34a and has an internal space formed such that it is recessed to the inner side of the domed portion 34a. The internal space of the cylinder head cover 34 is divided by a vent plate 145 mounted on the cylinder head cover 34 from the inner side to form a vent chamber 34b.

The vent plate 145 is arranged so that it extends parallel to the coupling face 100t of the cylinder head 33 on the cylinder head cover side 34 leaving a predetermined distance between.

As shown in FIG. 9, end portions of the pin elements 142 and 143 extending through and protruding from the reinforcing plates 140 and 141 are closely placed in the vent plate 145 leaving a small gap between.

Accordingly, the amount of movement of the pin elements 142 and 143 mounted in the pin insertion holes 112p and 123p of the intake swing arm shaft support portion 112 and the exhaust swing arm shaft support portion 123 is restricted by the vent plate 145 mounted on the cylinder head cover 34. Consequently, the pin elements 142 and 143 are prevented from leaving the pin insertion holes 112p and 123p, respectively.

With reference to Figure 2 depicting a view of the power unit 20 incorporated in the vehicle as seen in front elevation, an outlet portion 34c of the breather chamber 34b of the cylinder head cover 34 has been formed into a portion upper of the bulged portion 34a so that its opening is directed to the right side (water pump side 150). A breather hose 146 is connected at its end portion to the outlet portion 34c, extends to the water pump side 150 and bends so that it is directed backwards. In addition, the breather hose 146 is connected to the clean side of the air filter 27.

Accordingly, the breather hose 146 does not interfere with the electromagnetic solenoid 75 mounted on the left side wall 100L of the cylinder head 33.

Next, a lubricating system in the cylinder head 33 and the valve mechanism 50 is described.

The clamping screw clamping hole 115 of the cylinder head 33 is used as an oil path supplied from the cylinder block side 32. With reference to Figures 7 and 13, an oil passage 131 has been formed from a intermediate portion of the clamping screw clamping hole 115 towards the upper wall 100U. The oil passage 131 is curved at its end portion and communicates with an oil passage 132 extending towards the left side wall 100L in the upper wall 100U. The oil passage 132 is curved at its end portion and communicates with an oil passage 133 extending towards the circular support hole 121 in the left side wall 100L.

In the cylinder head 33 tilted forward to a position near a horizontal position, the oil passage 132 drilled horizontally in the upper wall 100U has been placed in an upper position. Injection holes 132a and 132b have been formed in a bifurcated manner in two positions of the oil passage 132 above and corresponding to the first intake swing arm 57 and the second intake swing arm 58, respectively (see Figures 6 and 13).

Oil injected from the injection holes 132a and 132b is dispersed to end portions of the valve side arm portions 57v and 58v and the adjustment screws 57t and 58t of the first intake swing arm 57 and the second intake swing arm 58, respectively (see Figures 6 and 10).

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The oil passage 133 on the left side wall 100L has been drilled near the electromagnetic solenoid 75 mounted on the left side wall 100L and extends through the holding hole of captive thyme 125. In addition, the oil passage 133 passes in a crossover relationship with the intake support of the tilting arm axle 122h leaving a distance between. The oil passage 133 communicates at its end portion with an oil inlet passage 134 that has been formed so as to extend to the left of the circular support hole 121 shown in Figure 8 (see Figures 13 and 14) .

It should be noted that the captive screw retaining hole 125 is structured such that it is closed at its top and bottom.

An oil fork passage 133a connects the oil passage 133 and the intake rocker arm shaft support hole 122h which intersects the oil passage 133 with each other (see Figures 9 and 18).

With reference to Figure 8, the camshaft 54 has an axis hole 54a that opens at its left end facing the oil inlet passage 134 and has extraction oil passages 54b, 54c and 54d drilled therein in a diametral direction from the shaft hole 54a.

Accordingly, the oil introduced to the shaft hole 54a of the camshaft 54 from the oil passage 133 through the oil inlet passage 134 lubricates the support portions by communicating the extraction oil passage 54b on the left side with the hole of circular support 121 of the left side wall 100L. Meanwhile, the extraction oil passage 54c in the center is open to an outer peripheral face of the second inlet eccentric lobe 54H so that the oil lubricates the sliding contact portion of the second inlet eccentric lobe 54ii with the skate 58s of the second inlet swing arm 58. In addition, the extraction oil passage 54d on the right side is open towards the decompression mechanism 85 so that the oil lubricates the decompression mechanism 85.

Referring to Figure 9, the intake rocker arm shaft 55 mounted and supported by the intake rocker arm shaft support hole 122h has an open shaft hole 55a at its left end. An oil introduction passage 55b has been formed in a portion of the intake rocker arm shaft 55 on the left side of the shaft hole 55a such that it extends through the shaft hole 55a coaxially with the bifurcation passage of oil 133a. The oil diverted from the oil passage 133 to the oil fork passage 133a enters the shaft bore 55a from the oil introduction passage 55b of the intake swing arm shaft 55. In addition, an oil passage has been formed. extraction 55c on the axis of the swinging arm 55 near the right end of the shaft hole 55a from the shaft hole 55a towards the second guide hole 58gh of the second swing arm of intake 58 (see Figure 10).

With reference to FIG. 10, an oil introduction passage 58d has been formed in the second inlet swing arm 58 such that it communicates the extraction oil passage 55c and the right end side of the second guide hole 58gh one with another.

An adjustment oil passage 58e has been formed in the valve side arm portion 58v of the second intake rocker arm 58 such that it extends upwardly out of the right end side of the second guide hole 58gh.

Accordingly, the oil introduced to the second guide hole 58gh of the shaft hole 55a of the second intake swing arm 58 through the extraction oil passage 55c and the oil introduction passage 58d lubricates the disconnect piston 72 for sliding movement. The oil is discharged after the passage of adjusting oil 58e to the sliding movement of the disconnect piston 72 and then adjusted.

It should be noted that the valve side arm portion 57v of the first intake swing arm 57 has an oil introduction passage 57d drilled therein so that it extends upwardly out of the first guide hole 57gh. The valve side arm portion 57v also has an oil passage 57e drilled on the opposite side and coaxially with the oil introduction passage 57d.

The oil dispersed to an upper end portion of the valve side arm portion 57v of the first intake rocker arm 57 flows along the surface of the valve side arm portion 57v to the oil introduction passage 57d and lubricates the disconnect piston 72 for sliding movement. In addition, the first intake rocker arm 57 is lubricated for swinging movement by the oil passing through the oil passage 57e.

The oil supply hole 130 communicates the rod slide hole 102 into which the operating rod 76 of the electromagnetic solenoid 75 and the push rod 74 of the variable valve apparatus 70, and the inner side space of the cylinder head have been inserted of cylinder 33 with each other. The oil supply hole 130 is positioned below an outer periphery of an annular open end face 125t of the clamping screw retaining hole 125 as seen in the axial linear direction of the cylinder shown in Figure 13 of

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the cylinder head 33 that swings forward to a position near the horizontal position. An oil guide groove 135 has been formed between the coupling face 100t of the cylinder head 33, which has been formed on the left side along the outer periphery of the open end face 125t, and the face of open end 125t.

The oil guide groove 135 introduces oil injected from the oil passage 132 into the upper wall 100U of the cylinder head 33 through the injection hole 132a, etc., and adhered to the wall face of the cylinder head 33 on the upper wall side 100U to the oil supply hole 130.

A rib 136 is provided that extends to the left horizontally from a position where it contacts a lower edge of the oil supply hole 130 below the oil guide groove 135 to the coupling face 100t. Also the oil that remains above the rib 136 is introduced into the oil supply hole 130.

In addition, as shown in Figure 7, the captive screws 180 extend through the captive screw retaining holes 125 and fix the reinforcing plate 141 together with the cylinder head 33, and the hexagonal nuts 181 are screwed into the captive screws 180. The hexagonal nuts 181 are fixed in such a way that their angular portion is directed specifically downwards compared to the other angular portions. Accordingly, the oil adhered to the hexagonal nuts 181 is guided by the angular portions directed downwards and flows downward along the surface of the reinforcing plate 141 from the angular portions and then returns to a side edge of the sheet of reinforcement 141. Therefore, the oil is easily introduced into the oil supply hole 130.

In the variable valve apparatus 70 of the present invention, when the solenoid solenoid 75 is in an inactive state (state in which the first and second intake swingarms 57 and 58 are not connected to each other by the connecting pin 71 and can swing independently of each other), the interleaved interior space 80 defined by and between the operating rod 76 and the pushing rod 74 in the rod sliding hole 102 is positioned as illustrated in Figure 10. In this position of the interleaved interior space 80, the oil supply hole 130 for supplying oil to the interleaved interior space 80 is deflected to the side of the push rod 74 (right side) such that a left end portion of the push rod 74 faces the hole of oil supply 130 while the operating rod 76 is positioned so as not to look at the oil supply hole 130. Consequently, the space interleaved interior 80 has a positional relationship such that part of it communicates with the oil supply hole 130.

The oil supply hole 130 has a positional relationship such that it is directed in the axial linear direction of the cylinder and has a spaced central axial line and that intersects perpendicularly with that of the rod sliding hole 102. The area of the communication hole in the boundary between the oil supply hole 130 and the rod sliding hole 102 is small compared to that where its central axial lines intersect perpendicularly with each other. In addition, when the electromagnetic solenoid 75 is in an inactive state, the oil supply hole 130 is deflected to the side of the push rod 74 with respect to the interleaved interior space 80. Accordingly, the communication hole in the boundary between the hole of oil supply 130 and the rod slide hole 102 is partially closed by the push rod 74. Therefore, the interleaved interior space 80 assumes a state close to a closed space.

In Figure 10, the oil supplied from the oil supply hole 130 to the interleaved interior space 80 when the electromagnetic solenoid 75 is in an inactive state is indicated by scattered points.

As seen in Figure 10, the interleaved interior space 80 is only partially communicating with the oil supply hole 130, but is in a state close to the state of a closed space.

In addition, as shown in Figure 7, the reinforcing plate 141 which bridges the open end portions of the clamping screw retaining holes 125 and 126 of the left side wall 100L of the cylinder head 33 covers approximately half of the opening of the oil supply hole 130 as seen in the axial linear direction of the cylinder. Therefore, oil leakage into the interleaved interior space 80 of the oil supply hole 130 is prevented.

Thus, when the electromagnetic solenoid 75 is in an inactive state, the interleaved interior space 80 filled with oil supplied from the oil supply hole 130 is in a state close to a closed space, and oil is prevented from leaving the hole. of oil supply 130. Therefore, at an initial stage when the electromagnetic solenoid 75 is operated so as to protrude the operating rod 76, the outflow of oil present in the interleaved interior space 80 of the oil supply hole 130 is prevented Accordingly, the damping function of the operating rod 76 can be increased as an oil damper that pushes the push rod 74 through the oil in the interleaved interior space 80, and the impact or vibration by collision can be dampened.

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When the operating rod 76 is moved to the right by the operation of the electromagnetic solenoid 75, also the push rod 74 moves to the right through the oil present in the interleaved interior space 80.

Since also the interleaved interior space 80 moves to the right together with the movement of the push rod 74, the amount of deviation of the oil supply hole 130 deflected to the right with respect to the interleaved interior space 80 decreases. Accordingly, although the oil present in the interleaved interior space 80 gradually leaves the oil supply hole 130, the interleaved interior space 80 is smaller and the operating rod 76 approaches the thrust rod 74 until it finally rests on the oil stem. push 74.

Accordingly, since the operating rod 76 rests on the push rod 74 in such a way that it retains the push rod 74 in a state in which the push rod 74 is moving to the right, the contact impact can be very low.

An operating state of the electromagnetic solenoid 75 when the operating rod 76 ends the movement to the right is illustrated in Figure 11.

The push rod 74 and the connecting pin 71 are shifted to the right together with the operating rod 76, and the connecting pin 71 connects the first and second intake swingarms 57 and 58 to each other so that they fully swing one with another. The right end of the operating rod 76 contacts the left end of the push rod 74 eliminating the interleaved interior space 80, and the support portion is placed in contact with the right side of the oil supply hole 130.

If the electromagnetic solenoid 75 changes from an active state to an inactive state, then the operating rod 76 is moved to the left immediately by the spring 79 of the electromagnetic solenoid 75. After the movement to the left of the operating rod 76, the push rod 74 is moved to the left by the spring 73 through the connecting pin 71 and the piston 72.

When the movement to the left of the push rod 74 and the operating rod 76 is stopped, the interleaved interior space 80 is again formed. Therefore, when the operating rod 76 stops, the interleaved interior space 80 communicating with the Oil supply hole 130 can be filled with oil.

Figure 12 illustrates an example where the positional relationship between the interleaved interior space 80 and the oil supply hole 130 is changed when the electromagnetic solenoid 75 is in an inactive state.

When the electromagnetic solenoid 75 is inactive, the oil supply hole 130 deflects a large amount next to the push rod 74 (right side) with respect to the interleaved interior space 80. Thus, the push rod 74 closes the hole completely communication at the boundary between the oil supply hole 130 and the stem sliding hole 102.

In other words, when the electromagnetic solenoid 75 is in an inactive state, the interleaved interior space 80 is a closed space.

Consequently, at an initial stage of the operation of the electromagnetic solenoid 75, little oil comes out of the interleaved interior space 80, and the damping function is maintained as an oil damper. Thus, an impact or vibration by collision can be efficiently cushioned.

When the operating rod 76 moves to the right to the operation of the electromagnetic solenoid 75, the interleaved interior space 80 also moves and communicates with the oil supply hole 130. Therefore, while the oil of the interior space interleaving 80 gradually exits through the oil supply hole 130, the interleaved interior space 80 is smaller and the operating rod 76 approaches the pushing rod 74 until it finally contacts the pushing rod 74.

Accordingly, since the operating rod 76 contacts the push rod 74 in such a way that it retains the push rod 74 in a state in which the push rod 74 moves to the right, the contact impact can be very low. .

An operating state of the electromagnetic solenoid 75 when the operating rod 76 ends the movement is indicated by a long line and two alternative shorts in Figure 12.

The support portion of the right end of the operating rod 76 with the left end of the push rod 74 faces the oil supply hole 130. A configuration can be adopted where, when the electromagnetic solenoid 75 changes from an active state to an inactive state , decreases the speed of the push rod 74 and stops faster than the operating rod 76. In this example, the operating rod 76 moves at a higher speed than the push rod 74, whereby the interleaved interior space 80 between the extreme

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left of the push rod 74 and the right end of the operating rod 76 is gradually larger. When the interleaved interior space 80 communicates with the oil supply hole 130, oil can be drawn into the interleaved interior space 80 through the oil supply hole 130. As a result, when the operating rod 76 stops, the interleaved interior space 80 is filled with oil.

In the variable valve apparatus 70 of the internal combustion engine of the OHC type 30 of the present invention, the housing boxes 77 and 78 that house the main body of the electromagnetic solenoid 75 which serves as a source of generating pressure force mounted on the wall face of the left side wall 100L in which the spark plug 49 of the cylinder head 33 is disposed protruding, are arranged in a position where they do not overlap with the central axial line of spark plug Cs directed by the spark plug 49 as seen in the axial linear direction of the cylinder as shown in Figures 7 and 14. Therefore, the electromagnetic solenoid 75 can be arranged in a position where it does not constitute an obstacle when the spark plug of ignition 49 is moved for assembly or disassembly in the axial linear direction of the central axial line of spark plug Cs directed by spark plug 49 without at ejecting the electromagnetic solenoid 75 from the spark plug 49. Therefore, at the same time that the miniaturization of the cylinder head 33 is achieved, the maintenance operation of the spark plug 49 can be favorably maintained.

Since the electromagnetic solenoid 75 has been placed on the head cover side 34 with respect to the spark plug 49 as shown in Figures 3 and 14, the maintenance space around the spark plug 49 can be easily secured. .

Since the push rod 74 and the operating rod 76 which are elements of pressure force transmission have been arranged for sliding movement in the cylinder head 33 as shown in Figure 10, the bulge of the electromagnetic solenoid 75 can be avoided , which provides pressure force to the push rod 74 and the operating rod 76, next to the cylinder head cover 34. Accordingly, the increase in size of the cylinder head 33 and peripheral elements in the axial linear direction of cylinder.

Therefore, the variable valve apparatus 70 may be suitable in particular for the scooter type motorcycle 1 which is a vehicle of the astride type and for which the miniaturization of the cylinder head 33 and peripheral elements is demanded.

As shown in Figures 3 and 14, in the electromagnetic solenoid 75, the multiple mounting arm portions 77pr, 77qr and 77rr are formed around the housing boxes 77 and 78 so that they extend radially along the length of the wall face of the left side wall 100L of the cylinder head 33. The mounting arm portions 77pr, 77qr and 77rr are mounted only on the cylinder head 33. Therefore, it is possible to raise the stiffness of the cylinder head cylinder 33 and better avoid bulging of the electromagnetic solenoid 75 next to the cylinder head cover 34.

In addition, the electromagnetic solenoid 75 is mounted only on the cylinder head 33, but not on the cylinder head cover 34. Therefore, upon maintenance of the valve system on the cylinder head 33, the cylinder head cover 34 can be removed without removing solenoid 75. Consequently, the maintenance operation of the valve system can be easily carried out.

With reference to Figures 3 and 14, between the mounting arm portions 77pr, 77qr and 77rr of the electromagnetic solenoid 75, in the mounting arm portion 77pr extending in a direction that overlaps the central axial line of spark plug Cs as seen in the axial linear direction of the cylinder the recessed portion 77d has been formed. The recessed portion 77d opens towards the spark plug side 49 in such a way that it crosses, but stays away from the central axial line of spark plug Cs. Therefore, when the spark plug 49 is moved in a direction of the central axial line of spark plug Cs for assembly or disassembly, the mounting arm portion 77pr does not constitute an obstacle due to the lowered portion 77d. Consequently, a good maintenance operation of the spark plug 49 can be favorably maintained.

As shown in Fig. 14, the nerve portions 103pr, 103qr and 103rr with which the mounting arm portions 77pr, 77qr and 77rr that extend from the periphery of the housing boxes 77 and 78 and the portions of Mounting protrusion 103p, 103q and 103r at the end portions of the nerve portions 103pr, 103qr and 103rr are formed by protruding in the cylinder head 33. Therefore, the electromagnetic solenoid 75 is stably retained in the cylinder head 33 through the nerve portions 103pr, 103qr and 103rr and the mounting boss portions 103p, 103q and 103r.

In addition, the mounting arm portions 77pr, 77qr and 77rr of the electromagnetic solenoid 75 contact and mount with / in the nerve portions 103pr, 103qr and 103rr and the mounting boss portions 103p, 103q and 103r. Therefore, the nerve portions 103pr, 103qr and 103rr and the mounting boss portions 103p, 103q and 103r can be maintained in a state of high rigidity. Consequently, electromagnetic solenoid 75 can be more firmly supported.

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The housing boxes 77 and 78 and the mounting arm portions 77pr, 77qr and 77rr of the electromagnetic solenoid 75 are made of metal. Therefore, the heat generated in the housing boxes 77 and 78 for the electromagnetic solenoid 75 can be transmitted from the mounting arm portions 77pr, 77qr and 77rr to the nerve portions 103pr, 103qr and 103rr. Therefore, the heat radiation efficiency of the electromagnetic solenoid 75 can be improved.

In addition, the nerve portions 103pr, 103qr and 103rr and the mounting boss portions 103p, 103q and 103r are formed by protruding on the wall face of the left side wall 100L of the cylinder head 33. Therefore, the portions of the mounting arm portions 77pr, 77qr and 77rr supporting the nerve portions 103pr, 103qr and 103rr and the mounting projection portions 103p, 103q and 103r protruding from the support face cooperate with the wall face of the left side wall 100l of the cylinder head 33 forming a space in between (see Figure 8). When running wind enters the space, the mounting arm portions 77pr, 77qr and 77rr can be cooled, and consequently, the cooling effect can be increased.

As shown in Figures 10 and 14, the oil passage 133 has been formed in the left side wall 100L, in which the electromagnetic solenoid 75 of the cylinder head 33, near the electromagnetic solenoid 75, has been mounted. therefore, the electromagnetic solenoid 75 can be effectively cooled by the oil flowing in the oil passage 133.

The internal combustion engine of the OHC 30 type of the present invention is incorporated into the vehicle frame of the scooter type motorcycle 1, which is a vehicle of the astride type, in a position where the axial cylinder line Cc it swings forward largely to a position close to a horizontal position. In addition, the electromagnetic solenoid 75 which is a source of pressure force generation is mounted on the wall face of the left side wall 100L of the cylinder head 33 which is directed in the vehicle width direction. In addition, the outer side of the electromagnetic solenoid 75 in the vehicle width direction is covered with the connecting tube 6 which is part of the vehicle frame. Therefore, the electromagnetic solenoid 75 is disposed between the cylinder head 33 and the connecting tube 6. Accordingly, the electromagnetic solenoid 75 can be effectively protected against an external factor by the cylinder head 33 and the connection tube 6 .

As shown in Figure 2, the water pump 150 is mounted on the wall face of the right side wall 100R on the side opposite the wall face of the left side wall 100L on which the electromagnetic solenoid 75 is mounted of the cylinder head 33. Therefore, the electromagnetic solenoid 75 and the water pump 150, which are heavy elements, are distributed distributed on the opposite side wall faces directed in the vehicle width direction of the vehicle. cylinder head 33 so that they do not interfere with each other. Consequently, the weight balance around the cylinder head 33 can be improved. In addition, also where both the electromagnetic solenoid 75 and the water pump 150 are mounted on the cylinder head 33, the spark plug maintenance operation 49 can be carried out favorably by mounting the spark plug 49 in such manner illustrated in the Figure 3 on the left side wall 100L on which the electromagnetic solenoid 75 is mounted.

As shown in FIG. 2, the breather chamber 34b is disposed on the inner side of the cylinder head cover 34, and the outlet portion 34c of the breather chamber 34b has been formed on the outer wall face of the cover of cylinder head 34 such that its opening is directed to the water pump side 150 in the vehicle width direction. Therefore, the breather hose 146 connected to the outlet portion 34c of the breather chamber 34b of the cylinder head cover 34 and extending to the water pump side 150 does not interfere with the electromagnetic solenoid 75 on the opposite side . It is also easy to prevent the vent hose 146 from interfering with the water pump 150 disposed on the crankcase side 31 with respect to the electromagnetic solenoid 75.

In the embodiment described above, the oil supply hole 130 with respect to the interleaved interior space 80 when the electromagnetic solenoid 75 is in an inactive state is deflected to the push rod side 74 (right side). However, the oil supply hole 130 with respect to the interleaved interior space 80 can alternately be diverted to the operating rod side 76 (left side).

However, a configuration must be used in which, when the electromagnetic solenoid 75 is in an inactive state, the oil supply hole 130 is in a state of communication with the interleaved interior space 80 and oil is supplied to the interleaved interior space 80.

In the configuration just described, when the electromagnetic solenoid 75 is in an inactive state, the right end portion of the operating rod 76 closes part of the communication hole at the boundary between the oil supply hole 130 and the sliding hole. of stem 102. Therefore, the interleaved interior space 80 is in a state close to that of a closed space.

Accordingly, at an initial stage when the electromagnetic solenoid 75 is made operative by protruding the operating rod 76, the oil leakage into the interior space sandwiched 80 by the supply hole is prevented

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of oil 130. Therefore, the damping function as an oil damper for pushing the push rod 74 through the oil in the interior space sandwiched 80 by the operating rod 76 can be improved, and the impact and the impact can be cushioned. vibration produced by collision.

In the variable valve apparatus 70 for the internal combustion engine of the OHC type 30 of the present invention, the connecting pin 71 is disposed between the introduction holes of the swing arm shaft 57h and 58h for the first and second swing arms 57 and 58 and the drive side end portions 57vv and 58vv acting on the first and second intake valves 61 and 62 as depicted in Figure 6. Therefore, the connecting pin 71 can be arranged not in a very domed position on the cylinder head cover side 34 from the intake rocker arm axis 55, but in a position closer to the intake rocker arm axis 55 in the axial linear direction of the cylinder on the crankcase side 31. Therefore, there is no need to make the first and second intake swingarms 57 and 58 bulge to the side of the cylinder head cover 34 to increase its size. In addition, increasing the size of the cylinder head 33 and the cylinder head cover 34 can be avoided.

In addition, the rod slide hole 102 which is a pressure force transmission element slide hole has been formed in the cylinder head 33 in the position in which it overlaps with the pivot arm shaft support hole. intake 122h in the axial linear direction of the cylinder between the clamping screw clamping hole 125 and the tilting arm shaft support hole 122h as shown in Figure 10. Therefore, the push rod 74 and the rod operative 76, which are elements of pressure force transmission, can be arranged compactly by making use of the space between the clamping screw clamping hole 125 and the intake support arm of the tilting arm 122h. In addition, the push rod 74 and the operating rod 76, which are pressure force transmission elements, are disposed in the position in which they overlap with the intake swing arm shaft 55 in the axial linear direction of the cylinder. Therefore, the cylinder head 33 can be miniaturized in the axial linear direction of the cylinder, and the increase in size of the cylinder head 33 and the cylinder head cover 34 can be better avoided.

Specifically, since the internal combustion engine of the OHC 30 type to be incorporated in the scooter type motorcycle 1 of the present invention, which is a vehicle of the astride type in which it is difficult to secure a space, the engine can be properly applied OHC type internal combustion of the present invention that prevents the increase of cylinder head size 33 and associated elements.

It should be noted that, although, in the present embodiment, the push rod 74 and the operating rod 76 as pressure force transmission elements are formed as separate elements, it is also possible in the present invention to apply them as a single rod.

In addition, the adjustment screws 57t and 58t for adjusting the support position with the first and second intake valves 61 and 62 are screwed into the drive side end portions 57vv and 58vv of the first and second intake swingarms 57 and 58 as shown in Figure 6. In addition, the axial line Cp of the connecting pin 71 is disposed between the end portions of the cylinder head side 57tt and 58tt of the adjustment screws 57t and 58t and the axial line Cr of the introduction holes of swing arm shaft 57h and 58h in the axial linear direction of the cylinder. Therefore, the intake rocker arm shaft 55, the connecting pin 71 and the adjustment screws 57t and 58t can be juxtaposed in a substantially straight line. Accordingly, the valve side arm portions 57v and 58v of the first and second intake swingarms 57 and 58 from the swing arm shaft insertion holes 57h and 58h to the drive side end portions 57vv and 58vv acting on the first and second intake valves 61 and 62 can be formed substantially in the form of a coating. Therefore, the first and second intake swingarms 57 and 58 can be miniaturized with high spatial efficiency.

In addition, the portions of the first and second inlet swing arms 57 and 58 on which the connecting pin 71 for movement is mounted, are formed with an increased thickness the amount by which the connecting pin 71 is mounted and supported. Therefore, the stiffness of the valve side arm portions 57v and 58v from the swing arm shaft insertion holes 57h and 58h to the drive side end portions 57vv and 58vv acting on the intake valves First and second 61 and 62 can be increased.

The connecting pin 71 and the push rod 74 and the operating rod 76, which are pressure force transmission elements, are arranged on the crankcase side 31 with respect to the coupling face 100t between the cylinder head 33 and the cylinder head cover 34 as shown in Fig. 6. Therefore, the intake rocker arm shaft 55, the connecting pin 71 and the adjustment screws 57t and 58t are juxtaposed in a straight line, and the screws of Adjustment 57t and 58t are placed near the coupling face 100t between the cylinder head 33 and the cylinder head cover 34. Accordingly, an adjustment operation of the adjustment screws 57t and 58t can be easily carried out.

Especially, the connecting pin 71, the push rod 74 and the operating rod 76 are positioned on the crankcase side 31 with respect to the end portions of the cylinder head side 57tt and 58tt of the adjustment screws 57t and

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58t. Therefore, an adjustment operation by the adjustment screws 57t and 58t can be carried out more easily.

The push rod 74 and the operating rod 76 are adjacent to the captive threads 180 as shown in Figures 6 and 7. Therefore, the captive screw clamping hole 125 and the rod sliding hole 102, which is a sliding hole of the pressure force transmission element 102 of the cylinder head 33, can be placed as close as possible to the intake support arm of the tilting arm 122h. Consequently, the miniaturization of the cylinder head 33 can be anticipated.

The axial line Cd of the push rod 74 and the operating rod 76 is placed on the crankcase side 31 with respect to the axial line Cp of the connecting pin 71 as shown in Figure 6. Therefore, the electromagnetic solenoid 75 which pushes the push rod 74 and the operating rod 76 can be arranged near the crankcase side 31. Accordingly, the amount of bulging of the electromagnetic solenoid 75 to the cylinder head cover side 34 in the axial linear direction of the cylinder can be reduced .

In addition, the axial line Cd of the push rod 74 and the operating rod 76 is positioned on the axis side of the intake swing arm 55 with respect to the axial line Cp of the connecting pin 71 as shown in Figure 6. By therefore, a configuration can be efficiently implemented where, while the push rod 74 and the operating rod 76 avoid interference with the captive screws 180, they push the connecting pin 71.

The electromagnetic solenoid 75 is firmly fixed only to the cylinder head 33 as shown in Figures 3 and 14. Therefore, the shape of the coupling face between the cylinder head 33 and the cylinder head cover 34 can be simplified. . In addition, since the need to fix the electromagnetic solenoid 75 to the cylinder head cover side 34 is eliminated, the simplification of the cylinder head cover 34 can also be achieved.

In addition, by maintaining the valve system in the cylinder head 33, the cylinder head cover 34 can be removed without removing the solenoid solenoid 75. Therefore, the maintenance operation of the valve system can be facilitated.

A variable valve apparatus is provided for an internal combustion engine of the OHC type and includes a crankcase (31), a cylinder block (32) and a cylinder head (33) placed in order in the crankcase (31) and fixed jointly by a plurality of captive screws (180) extending through the cylinder block (32) and the cylinder head (33) in an axial direction of cylinder line, a plurality of tilting arms (57, 58) arranged and supported for tilting movement in a mutually contiguous relationship on a tilting arm axis (55) inside the cylinder head (33) and operable in an interlocking relationship with engine valves (61, 62), and a cover of cylinder head (34) placed in the cylinder head (33) to cover the cylinder head (33). The variable valve apparatus includes: a connecting pin (71) mounted for movement in an axial direction of the tilting arm axis (55) in the tilting arms (57, 58) positioned adjacent to each other and movable between a connecting position wherein the connecting pin (71) connects the swingarms (57, 58) positioned adjacent to each other for integral swinging and a disconnecting position in which the connecting pin (71) disconnects the swinging arms (57, 58) from one another to allow independent swinging of each of the swinging arms (57, 58); and a pressure force transmission element (74, 76) configured to transmit pressure force from a source of pressure force generation (75) disposed outside the cylinder head (33) to the connecting pin (71) for move the connecting pin (71). The source of pressure force generation (75) is mounted on a wall face (100L) of the cylinder head (33) in which a spark plug (49) is arranged protruding. A housing box (77, 78) that accommodates a main body of the pressure force generating source (75) is arranged in a position where the housing box (77, 78) does not overlap with an axial line central spark plug (Cs), which is directed by the spark plug (49), as seen in the axial direction of the cylinder line.

The source of pressure force generation (75) may be placed on the cylinder head cover side (34) with respect to the spark plug (49).

The pressure force transmission element (74, 76) can be arranged for sliding movement in the cylinder head (33).

The source of pressure force generation (75) can have a plurality of mounting arm portions (77pr, 77qr, 77rr) formed around the housing (77, 78) so that they extend radially along The wall face (100L) of the cylinder head (33), and the mounting arm portions (77pr, 77qr, 77rr) can only be mounted on the cylinder head (33).

Between the mounting arm portions (77pr, 77qr, 77rr), the arm mounting portion (77pr) that extends in a direction that overlaps the central axial line of spark plug (Cs) as seen in the axial direction of the cylinder line can have a recessed portion (77d) formed on top so that it opens towards the spark plug side (49) such that the recessed portion (77d) crosses but stays away from the line Axial central spark plug (Cs).

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In the cylinder head (33), nerve portions (103pr, 103qr, 103rr) with which the mounting arm portions (77pr, 77qr, 77rr) that extend from the periphery of the housing (77) can contact , 78), and mounting boss portions (103p, 103q, 103r) at end portions of the nerve portions (103pr, 103qr, 103rr) can be formed by protruding, and the mounting arm portions (77pr, 77qr, 77rr) can be mounted on the mounting boss portions (103p, 103q, 103r).

The housing (77, 78) and the mounting arm portions (77pr, 77qr, 77rr) of the source of pressure force (75) can be made of a metal.

On the wall face (100L) on which the source of pressure force generation (75) of the cylinder head (33) is mounted, an oil passage (133) can be formed in the vicinity of the source of pressure force generation (75).

The internal combustion engine of the OHC type (30) can be mounted on a vehicle frame of a straddle type vehicle (1) in a position where an axial cylinder line (Cc) swings forward in large measured at a position close to a horizontal position. The source of pressure force generation (75) can be mounted on the side wall face (100L) of the cylinder head (33) directed in the vehicle width direction. The source of pressure force generation (75) may be covered on its outer sides in the vehicle width direction with part (6) of the vehicle frame.

A water pump (150) can be mounted on a side wall face (100R) of the cylinder head (33) on the side opposite the side wall face (100L) on which the source of pressure force generation (75) is mounted.

The water pump (150) can be arranged on the crankcase side with respect to the source of pressure force generation (75) in the axial direction of the cylinder line. A vent chamber (34b) can be arranged on the inner side of the cylinder head cover (34). An outlet portion (34c) of the breather chamber (34b) can be formed on an outer wall face of the cylinder head cover (34) such that its opening is directed to the water pump side (150) in the width of the vehicle

[Description of reference symbols]

1: scooter type motorcycle, 4: ground pipe, 5: main pipe, 6: connecting pipe, 20: power unit, 30: internal combustion engine, 31: crankcase, 32: cylinder block, 33: cylinder head cylinder, 34: cylinder head cover, 34b: breather chamber, 49: spark plug, 50: valve mechanism, 54: camshaft, 55: intake swing arm shaft, 56: exhaust swing arm shaft, 57: first intake swing arm, 57t: adjustment screw, 57h: swing arm shaft insertion hole, 58: second intake swing arm, 58t: adjustment screw, 58h: swing arm shaft insertion hole, 59: rocker arm, 61: first intake valve, 62: second intake valve, 63: first exhaust valve, 64: second exhaust valve, 70: variable valve device, 71: connecting pin, 72: disconnecting piston, 74: push rod, 75: electromagnetic solenoid, 76: operating rod, 77: housing box, 77a: cylindrical portion, 77b: lower wall portion, 77p, 77q, 77r: mounting boss portion, 77pr, 77qr, 77rr: mounting arm portion, 77d: recessed portion, 80: space interleaved inner, 100: outer peripheral wall, 100L: left side wall, 100R: right side wall, 101: spark plug mounting hole, 102: stem sliding hole, 103p, 103q, 103r: mounting boss portion , 103pr, 103qr, 103rr: nerve portion, 104p, 104q, 104r: bolt, 110: inner wall, 112: intake arm support arm, 112h: intake support arm support arm, 113: exhaust rocker arm shaft support portion, 113h: exhaust rocker arm shaft support hole, 115, 116: captive screw clamping hole, 122: intake rocker arm shaft support portion, 122h: adm tilt arm shaft support hole sion, 125, 126: captive screw clamping hole, 130: oil supply hole, 131, 132, 133: oil passage, 135: oil guide groove, 136: rib, 140, 141: reinforcing plate , 146: breather hose, 150: water pump, 180: captive screw, 181: hexagonal nut.

Claims (8)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. A straddle type vehicle including, supported for tilting movement in a vehicle frame, a power unit (20) including an OHC type internal combustion engine (30) and a continuously variable transmission of the type of belt (21); the internal combustion engine of the OHC type (30) having an axial cylinder line (Cc) tilted to a large extent and provided with a plurality of tilting arms (57, 58) arranged and supported for tilting movement in a mutually contiguous relationship on a tilting arm axis (55) and operable in an interlocking relationship with motor valves (61, 62); a connecting pin (71) mounted for movement in an axial direction of the swing arm axis (55) in the swing arms (57, 58) positioned adjacent to each other is arranged so that it is movable between a connection position in the that the connecting pin (71) connects the swinging arms (57, 58) positioned adjacent to each other for integral swinging and a disconnecting position in which the connecting pin (71) disconnects the swinging arms (57) , 58) from one another to allow independent swinging of each of the swinging arms (57, 58); a pressure force transmission element (74, 76) being provided that transmits pressure force from a source of pressure force generation (75) disposed outside the internal combustion engine of the OHC type (30) to the connecting pin (71 ) to move the connecting pin (71) in the vehicle width direction, where the internal combustion engine of the OHC type (30) has side walls (100L, 100R) directed in the width-wide direction of the vehicle and side walls (100U, 100S) directed in the vertical direction, jointly assuming the side walls a shape tubular rectangular, the source of pressure force generation (75) being mounted on one of the side walls (100L, 100R) directed in the vehicle width direction, and part of the vehicle frame is arranged on an outer side of the source of pressure force generation (75) in the vehicle width direction, where the vehicle frame includes a front tube (2), a down tube (3) that extends down the front tube (2), and a pair of left and right floor tubes (4) that extend backwards under of a floor section (1c), which is arranged between a front section of the vehicle body (1f) and a rear section of the vehicle body (1r), of the descending tube (3), which rises obliquely upward in a portion rear of the floor section (1c) and extending backwards, and the source of pressure force generation (75) is located forward of the rear portions of the floor pipes (4) that rise obliquely upward and extend backwards, as seen in side view, where the rear section of the vehicle body (1r) including the source of pressure force generation (75) is covered by the left and right sides with a body cover (29e). 2. The straddle type vehicle according to claim 1, wherein a main tube (5) connected to the floor pipes (4) and extending backwards, and a connecting tube (6) protruding forward of the portions of the pair of left and right floor pipes (4) rising obliquely upwards and extending backwards and is connected to the main pipe (5), and at least part of the source of pressure force generation (75) is located under an upper end of the connecting tube (6), as seen in side view. 3. The straddle type vehicle according to claim 1 or 2, wherein the power unit (20) is supported for tilting movement in the vehicle frame through a pivot shaft (19), and The source of pressure force generation (75) is located forward of the pivot shaft (19), as seen in side view. 4. The straddle type vehicle according to any one of claims 1 to 3, where adjusting screws (57t, 58t) are screwed into action end portions (57vv, 58vv) of the swingarms (57, 58), and An axial line (Cp) of the connecting pin (71) is disposed between portions of the head end end (57tt, 58tt) of the adjusting screws (57t, 58t) and an axial line (Cr) of shaft insertion holes tilt arm (57h, 58h), and up the axial line (Cr) of the introduction holes of the tilt arm shaft (57h, 58h). 5. The straddle type vehicle according to any one of claims 1 to 4, including 5 10 fifteen twenty 25 30 35 a camshaft (54) configured to operate the tilting arms (57, 58), where the internal combustion engine of the OHC type (30) is provided with an eccentric chain chamber (52) through which an eccentric chain (51) extending between and around the camshaft (54) and a crankshaft (35), and the eccentric chain chamber (52) is formed between a side wall on the side opposite the side wall on which the source of pressure force generation (75), of the side walls (100L, 100R) directed at the width-wide direction of the vehicle, and an inner wall (110) on an inner side of a side wall. 6. The straddle type vehicle according to claim 5, wherein the camshaft (54) is supported for rotation in the inner wall (110) through a bearing (82), the eccentric chain chamber (52) is arranged adjacently and on one side in the width direction of the bearing vehicle (82), and A decompression mechanism (85) is incorporated into an exhaust eccentric lobe (54e) disposed adjacently and on the other side in the width direction of the bearing vehicle (82). 7. The straddle type vehicle according to any one of claims 1 to 6, where the source of pressure force generation (75) is provided with a protruding portion (77bb) adapted to support the pressure force transmission element (76) for sliding movement, the protruding portion (77bb) being formed in an outstanding manner for fitting in the internal combustion engine of the OHC type (30), and The source of pressure force generation (75) is mounted on the internal combustion engine of the OHC type (30) through an elastic ring (84) which is arranged in the projecting portion (77bb), and a sealing element (83) which is arranged between the internal combustion engine of the OHC type (30) and an end portion of the projecting portion (77bb). 8. The astride type vehicle according to any one of claims 1 to 7, where the OHC-type internal combustion engine (30) is a water-cooled internal combustion engine, and a water pump (150) is supported on a side wall on the side opposite the side wall on which the source of pressure force generation (75), of the side walls (100L, 100R) directed in the vehicle width direction.