JP5503468B2 - Variable valve timing valve - Google Patents

Description

  The present invention relates to a valve gear that makes a valve timing variable.

  Various valve gears have been proposed in which a variable cam member splined to a valve camshaft slides in the axial direction to change the valve timing by changing the cam acting on the intake and exhaust valves ( For example, see Patent Document 1).

JP 2002-256833 A

  In the valve operating device disclosed in Patent Document 1, a low speed cam and a high speed cam are formed on a cam piece that is spline-fitted on the outer periphery of a cam shaft, and the cam piece is slid in the axial direction so that an intake / exhaust valve is formed. The acting cam can be switched to either the low speed cam or the high speed cam.

In Patent Document 1, in the slider mechanism that slides the cam piece in the axial direction, the arm extending from the drive piston that reciprocates in parallel with the cam shaft is engaged with the engaging portion of the cam piece, and the drive piston is moved by hydraulic pressure. By doing so, the cam piece slides through the arm.
Therefore, since a large slider mechanism using a hydraulically driven piston is formed around the camshaft, the number of parts is complicated and the variable valve timing valve operating apparatus is increased in size and cost.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a variable valve timing valve operating apparatus that can be downsized with a simple structure with a small number of parts and low cost.

In order to achieve the above object, the invention according to claim 1 is configured to open and close the intake valve (33) and the exhaust valve (34) by a stationary cam portion ( 142 ) of intake and exhaust gas that rotates in conjunction with the crankshaft of the internal combustion engine. Valve camshaft ( 141 ), a variable cam member ( 150 ) that is spline-fitted on the outer periphery of the valve camshaft ( 141 ) and slidably displaced in the axial direction to vary the valve timing, and the variable cam In a variable valve timing valve operating apparatus comprising a slider mechanism ( 152 ) for sliding and displacing a member ( 150 ) in the axial direction,
The slider mechanism ( 152 ) is slidably inserted into the central shaft hole (141h ) of the valve camshaft ( 141 ), and slide rod ( 153 ) that slides under the action of the actuator (61); the valve operating cam shaft long hole formed in an elongated axially (141) the slide rod penetrates the (141s) (153) and the variable cam member (150) connecting members for connecting the (154) with the door, the valve operating said connecting member (154) on the long long end of the hole (141s) of the cam shaft (141) that abuts the sliding of the variable cam member (150) is Ru is regulated It is configured as a variable valve the valve operating cam shaft (141), by cold forging, wherein the stationary cam portion (142) and portions of said spline (141c) is characterized Rukoto formed integrally It is a timing valve operating device.

According to the second aspect of the present invention, the valve operating camshaft (141) rotates in conjunction with the crankshaft of the internal combustion engine and opens and closes the intake valve (33) and the exhaust valve (34) by the intake and exhaust steady cam portions (142). A variable cam member (150) that is spline fitted to the outer periphery of the valve camshaft (141) and slidably displaced in the axial direction to vary the valve timing, and the variable cam member (150) in the axial direction. In a variable valve timing valve operating apparatus having a slider mechanism (152) for sliding and displacing,
The slider mechanism (152) is slidably inserted into a central shaft hole (141h) of the valve camshaft (141) and slides under the action of an actuator (61). A connecting member (154) that connects the slide rod (153) and the variable cam member (150) through a long hole (141s) formed in the axial direction of the valve camshaft (141). with the door, the variable cam member (150) is simultaneously spigot fitting is spline fitted to the outer periphery of the valve operating cam shaft (141), said valve operating cam shaft (141), by cold forging, the site of the steady cam site (142) spline (141c) is variable valve timing valve operating system according to claim Rukoto integrally formed.

  According to a third aspect of the present invention, in the variable valve timing valve operating apparatus according to the first or second aspect, the variable cam member (50, 150) is disposed adjacent to the steady cam portion (42, 142), and the variable cam When the member (50, 150) is separated from the steady cam portion (42, 142) by a predetermined distance or more, the variable cam member (50, 150) does not act on the valve, and the variable cam member (50, 150) leaves a gap in the steady cam portion (42, 142). When close to each other, the variable cam member (50, 150) acts on the valve to change the valve timing.

  According to a fourth aspect of the present invention, in the variable valve timing valve operating apparatus according to the third aspect, the steady cam portion (42,142) includes an exhaust cam lobe (42e, 142e), and the variable cam member (50,150) is the exhaust cam lobe. When close to (42e, 142e), the variable cam member (50, 150) acts on the exhaust valve (34) to change the exhaust valve timing.

According to a fifth aspect of the present invention, in the variable valve timing valve operating apparatus according to any one of the first to fourth aspects, the connecting member (54,154) has a rod shape, and the slide rod (53,153) is vertical. The both ends of the valve camshafts (41, 141) penetrate the elongated holes (41s, 141s) provided opposite to each other and engage the variable cam members (50, 150).

According to a sixth aspect of the present invention, in the variable valve timing valve operating apparatus according to the fifth aspect , a straight line connecting the shaft center of the valve cam shaft (41, 141) and the top of the cam crest of the variable cam member (50, 150). On the other hand, the connecting members (54, 154) are arranged so as to be oriented in an angular direction of about 90 degrees.

Invention of claim 7, wherein, in the variable valve timing valve operating system according to any one of claims 1 to 6, wherein the valve operating cam shaft (41, 141) variable cam member (50, 150) the even strip The spline groove (41cs, 141cs) and the spline protrusion (50cs, 150cs) are spline-fitted, and the connecting member (54,154) is connected to the spline protrusion (50cs, 150cs) of the variable cam member (50, 150). ).

According to an eighth aspect of the present invention, in the variable valve timing valve operating apparatus according to the second aspect, the connecting member (154) is engaged with the inner surface portion (150i) of the spigot inner surface of the variable cam member (150). Features.

According to the variable valve timing valve operating apparatus of claim 1, the slider mechanism ( 152 ) is slidably inserted into the central shaft hole ( 141h ) of the valve operating camshaft ( 141 ), and the operation of the actuator (61) is performed. and receiving by sliding rods that slide (153), the valve operating cam shaft (141) to form axially long the elongated hole (141s) through the slide rod (153) and the variable cam member (150 ) and since and a coupling member for coupling (154) to be simple slider mechanism inside the small number of parts (152) the configuration of the valve operating cam shaft (141), a compact variable valve timing valve gear And cost reduction can be achieved.
Since the valve operating cam shaft (141) variable cam member (150) with respect to the slidably mounted in the axial direction by the spline engagement, variable cam member relative to the valve operating cam shaft (141) rotation direction of the (150) The relative positional accuracy is high, and the processing accuracy of the circumferential width (rotational direction width) of the long hole ( 141s ) of the valve camshaft (141 ) through which the connecting member ( 154 ) passes can be lowered, and the workability is improved. can do.

Since the sliding of the variable cam member ( 150 ) is restricted by the connection member ( 154 ) coming into contact with the long end of the long hole ( 141s ) of the valve camshaft ( 141 ), the valve camshaft The positional accuracy in the axial direction of the variable cam member ( 150 ) with respect to ( 141 ) can be improved.
In addition, the valve camshaft (141) has a steady cam portion (142) and a spline portion (141c) that are integrally formed by cold forging. The accuracy of the cam portion ((142), such as the cam phase, lift amount, and axial position, can be improved.

According to the variable valve timing valve operating apparatus according to claim 2, the slider mechanism (152) is slidably inserted into the central shaft hole (41h) of the valve operating camshaft (141), and the operation of the actuator (161). The sliding rod (153) that slides in response to the sliding rod (153) and the variable cam member (150) through a long hole (141s) formed in the axial direction in the valve camshaft (141). ), A simple slider mechanism (152) is configured with a small number of parts inside the valve camshaft (141), and the variable valve timing valve operating device is compact. And cost reduction can be achieved.
Since the variable cam member (150) is slidably mounted in the axial direction by spline fitting to the valve camshaft (141), the variable cam member (150) in the rotational direction of the valve camshaft (141) is attached. The relative position accuracy is high, and the processing accuracy of the circumferential width (rotation direction width) of the long hole (141s) of the valve camshaft (141) through which the connecting member (154) penetrates can be lowered, and the workability is improved. can do.

And since the variable cam member (150) is spline-fitted to the outer periphery of the valve camshaft (141) and inlay-fitted at the same time, the variable cam member (150) is coaxial with the valve camshaft (141) by the spigot fitting. Therefore, it is only necessary to secure the positioning of the variable cam member (150) in the rotational direction with respect to the valve drive cam shaft (141) without considering the coaxiality in spline fitting. , 150cs), it is not necessary to set the machining accuracy so high, and the cost can be reduced.
In addition, the valve camshaft (141) has a steady cam portion (142) and a spline portion (141c) that are integrally formed by cold forging. The accuracy of the cam phase (142), such as the cam phase, lift amount, and axial position, can be improved.

According to the variable valve timing valve operating apparatus of the third aspect, the variable cam member (50) is disposed adjacent to the intake / exhaust steady cam portion (42,142), and the variable cam member (50,150) is disposed in the steady cam portion (42,142). ), The variable cam member (50, 150) does not act on the valve.If the variable cam member (50, 150) comes close to the steady cam part (42, 142) with a gap, the variable cam member (50, 150) Since the valve timing is changed by operating, the variable cam member (50, 150) is brought close to the steady cam portion (42, 142) according to the operating state of the internal combustion engine so that the intake / exhaust valve is operated at the normal timing. Can be opened and closed at different predetermined timings.
Since the variable cam member (50, 150) is close to the steady cam part (42, 142) with a gap, the variable cam member (50, 150) adheres to the steady cam part (42, 142) due to the viscosity of the lubricating oil and smoothly slides. Can be prevented.

According to the variable valve timing valve operating apparatus of the fourth aspect, the steady cam portion (42, 142) includes the exhaust cam lobe (42e, 142e), and the variable cam member (50) is variable when close to the exhaust cam lobe (42e, 142e). The cam member (50, 150) acts on the exhaust valve (34) to open and close the exhaust valve (34) at a predetermined timing different from the normal exhaust valve timing by the exhaust cam lobe (42e, 142e), thereby remaining in the exhaust passage. It is possible to realize so-called EGR (exhaust gas recirculation) in which the exhaust gas returned to the combustion chamber is used for combustion.
This EGR device can be configured with a simple structure without requiring a special dedicated EGR valve or EGR port.
The cam lift of the variable cam member (50, 150) for EGR is small, so the load on the spline due to the force acting on the cam crest is small, and the variable cam member (50, 150) can be reduced in size and weight. The sliding of the members (50, 150) can be made better.

According to the variable valve timing valve operating apparatus of the fifth aspect , the connecting member (54,154) has a rod shape, vertically passes through the slide rod (53,153), and both ends thereof are opposed to each other of the valve operating camshaft (41,141). And the variable cam member (50, 150) is engaged with the variable cam member (50, 150) by passing through the connecting member (54, 154) by the slide rod (53, 153). When sliding in the direction, the connecting member (54, 154) receives a force at the center and acts equally on the variable cam member (50, 150) at both ends, so that the connecting member (54, 154) is prevented from tilting and the variable cam member ( 50, 150) can be made smoother.

According to the variable valve timing valve operating apparatus according to claim 6, the connecting member having a rod shape with respect to a straight line connecting the shaft center of the valve operating cam shaft (41, 141) and the top of the cam crest of the variable cam member (50, 150) ( 54, 154) are arranged to be oriented in an angular direction of approximately 90 degrees, the reaction force when the cam crest formed at the axial end of the variable cam member (50, 150) acts on the valve is variable cam member ( The connecting member (54,154) that engages 50,150) receives substantially evenly at both ends, preventing stress from being biased at the engaging portion at one end of the connecting member (54,154) and preventing smooth sliding of the variable cam member (50,150). can do.

According to the variable valve timing valve operating apparatus of claim 7 , the valve operating camshaft (41,141) and the variable cam member (50,150) are provided with an even number of spline grooves (41cs, 141cs) and spline protrusions (50cs, 150cs). ), The spline load is evenly distributed, and the connecting members (54,154) are connected to the thick spline ridges (50cs, 150cs) facing the variable cam members (50,150) at both ends. Engagement can be ensured by increasing the engagement margin between the connecting member (54,154) and the variable cam member (50,150) without engaging and increasing the variable cam member (50,150) in the radial direction.

According to the variable valve timing valve operating apparatus of the eighth aspect , since the connecting member (154) engages with the inlay inner peripheral surface portion (150i) in which the coaxiality of the variable cam member (150) is ensured, A force is applied to the peripheral surface portion (150i) via the connecting member (154), and the variable cam portion (150) can be smoothly slid and displaced while maintaining the coaxiality without falling down.

1 is an overall side view of a motorcycle equipped with an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a left side view in which the internal combustion engine is partially omitted, with a partial cross section. It is a right sectional view of the cylinder head of the internal combustion engine and its vicinity. It is a rear sectional view (IV-IV line sectional view of FIG. 11). It is the VV sectional view taken on the line of FIG. 4 and FIG. It is a disassembled perspective view of a valve cam shaft, a steady cam member, and a variable cam member. It is an exploded sectional view of a valve camshaft and a driven cam chain sprocket incorporating a slider mechanism and the like. It is the VIII-VIII sectional view taken on the line of FIG. It is a perspective view of a rocking arm. It is a top view of a cylinder head incorporating a valve operating mechanism. It is a top view of a head cover. It is a reverse view of the head cover. It is the XIII-XIII sectional view taken on the line of FIG. It is the XIV-XIV sectional view taken on the line of FIG. It is the XV-XV sectional view taken on the line of FIG. It is a longitudinal cross-sectional view around the valve operating camshaft of the variable valve timing valve operating apparatus according to another embodiment. It is the XVII-XVII sectional view taken on the line of FIG. It is a disassembled perspective view of a valve cam shaft and a variable cam member. It is an exploded sectional view of a valve cam shaft and a variable cam member. It is the XX-XX sectional view taken on the line of FIG. It is a XXI arrow line view of FIG.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
The internal combustion engine 10 according to the present embodiment is mounted horizontally on a motorcycle with a transmission integrally provided behind the internal combustion engine 10 with the crankshaft 11 oriented in the left-right direction that is the vehicle width direction.
In the present embodiment, the front, rear, left and right coincide with the front, rear, left and right when the vehicle is used as a reference.

FIG. 1 is an overall side view of a motorcycle 1 equipped with an internal combustion engine 10 according to an embodiment of the present invention.
The body frame 2 of the motorcycle 1 has a pair of left and right main frames 2m, 2m extending backwards slightly from the head pipe 2h and then bent downward to form steeply inclined portions 2ma, 2ma. Has reached.
Further, a pair of left and right down frames 2d, 2d extend downward from the head pipe 2h at an obliquely steep angle substantially parallel to the steeply inclined portion 2ma of the main frame 2m in a side view.

  The seat rails 2s, 2s extend rearward from the upper portions of the steeply inclined portions 2ma, 2ma of the main frames 2m, 2m through the gussets 2g, 2g, and the central portion of the seat rails 2s, 2s and the steeply inclined portions 2ma, 2ma. The back stays 2b and 2b connecting the lower part of the seat support the seat rails 2s and 2s.

In the body frame as described above, the front fork 3 is pivotally supported on the head pipe 2h, the front wheel Fw is pivotally supported at the lower end thereof, and the front end is pivotally supported below the steeply inclined portions 2ma and 2ma of the main frames 2m and 2m. The rear fork 4 extends rearward, a rear wheel Rw is pivotally supported at the rear end thereof, and a rear cushion 5 is interposed between the rear fork 4 and the gusset 2 g of the vehicle body frame 2.
A fuel tank 6 is installed in front of the main frames 2m and 2m, and a seat 7 is provided behind the fuel tank 6 and supported by seat rails 2s and 2s.

The internal combustion engine 10 suspended from the main frames 2m , 2m and the down frames 2d, 2d is an SOHC type air-cooled single-cylinder four-cycle internal combustion engine, with the crankshaft 11 oriented in the vehicle body width direction with respect to the vehicle body. The cylinder block 14, the cylinder head 15, and the head cover 16 are suspended in an upright posture by slightly tilting forward.
The fuel tank 6 covers the upper portion of the head cover 16 at the top of the slightly tilted cylinder of the internal combustion engine 10.

  An intake pipe 8 extends rearward from the cylinder head 15 of the internal combustion engine 10 to the air cleaner 8a via a throttle body. An exhaust pipe 9 extends forward from the cylinder head 15 and bends downward to bend the internal combustion engine 10. The lower part extends rearward and reaches the muffler 9m on the right side of the rear wheel Rw.

Referring to FIG. 2, in the internal combustion engine 10, a crankcase 13 that supports the crankshaft 11 is formed with a transmission chamber 13 </ b> M that houses a transmission behind the crankcase 13 </ b> C in which the crankshaft 11 is disposed. From the transmission chamber 13M, the output shaft 12 of the transmission protrudes to the left and constitutes a power unit.
Below the crank chamber 13C, an oil sump 13P is formed integrally with the bottom wall bulging somewhat downward to store oil.
The crankcase 13 forming the crank chamber 13C, the transmission chamber 13M, and the oil reservoir 13P has a left-right split structure.

On the front crank chamber 13C of the crankcase 13, a cylinder block 14 having one cylinder 14a and a cylinder head 15 are overlaid on the cylinder block 14 via a gasket. The cylinder head 15 and the cylinder block 14 are integrally fastened to the crankcase 13 together with 16, and the head cover 20 is covered above the cylinder head 15 via an elastic seal member 18 (see FIGS. 3 and 4).
The cylinder block 14, the cylinder head 15, and the head cover 20 stacked on the crankcase 13 extend upward from the crankcase 13 in a slightly forwardly inclined posture (see FIG. 2).

  A piston 31 is fitted in the cylinder 14a of the cylinder block 14 so as to be slidable back and forth (see FIG. 3), and the piston 31 and the crankshaft 11 are connected by a connecting rod 32 to constitute a crank mechanism.

  A combustion chamber 15z is formed in the cylinder head 15 so as to face the piston 31 in the cylinder axial direction corresponding to the cylinder 14a. An intake port 15i extends rearward from the combustion chamber 15z and forwards from the combustion chamber 60. An exhaust port 15e extends (see FIG. 3), and a spark plug 19 is attached to the ceiling wall of the combustion chamber 15z with the tip facing the combustion chamber 15z (see FIG. 4).

  As shown in FIG. 3, the intake valve 33 and the exhaust valve 34 that are slidably supported by the valve guide integrally fitted to the cylinder head 13 are driven by a valve mechanism 40 provided in the internal combustion engine 10. Thus, the intake opening of the intake port 15 i and the exhaust opening of the exhaust port 15 e are opened and closed in synchronization with the rotation of the crankshaft 11.

  Referring to FIGS. 3 and 4, the valve mechanism 40 is a SOHC in which a single valve camshaft 41 is pivotally supported in the left-right direction on a camshaft holder 16 fixed on the cylinder head 15. A rocker arm shaft 43e, 43i is supported by the camshaft holder 16 at the front and rear of the valve camshaft 41, and the intake rocker arm 44i is pivotally supported by the rear rocker arm shaft 43i so that it can swing freely. The exhaust rocker arm 44e is pivotally supported by the front rocker arm shaft 43e so as to be swingable.

  A cylindrical steady cam member 42 having an intake cam lobe 42i and an exhaust cam lobe 42e formed side by side on the outer peripheral surface is press-fitted into the valve camshaft 41, and the steady cam member 42 is integrally removed from the valve camshaft 41. It is fitted.

  The intake rocker arm 43i has one end roller 43ir in contact with the intake cam lobe 42i of the steady cam member 42, the other end in contact with the upper end of the valve stem of the intake valve 33, and the other exhaust rocker arm 44e has one end roller 44er in the steady cam. The member 42 is in contact with the exhaust cam lobe 42e, the other end is in contact with the upper end of the valve stem of the exhaust valve 34, and the intake cam rocker arm 44i is rotated by rotation of the steady cam member 42 (intake cam lobe 42i, exhaust cam lobe 42e) together with the valve operating camshaft 41. The exhaust rocker arm 44e swings at a predetermined timing to open and close the intake valve 33 and the exhaust valve 34.

The valve camshaft 41 has a driven cam chain sprocket 36 fixed to the end of the left shaft (see FIG. 4).
On the other hand, a drive cam chain sprocket 35 is fitted on the crankshaft 11, and a cam chain 37 is bridged between the drive cam chain sprocket 35 and the driven cam chain sprocket 36 thereabove (see FIG. 2). ), The rotational power of the crankshaft 11 is transmitted to the rotation of the valve operating camshaft 41 through the cam chain 37 at a half speed of the crankshaft 11, and the intake rocker arm 44i and the exhaust rocker arm are synchronized with the crankshaft 11. The intake valve 33 and the exhaust valve 34 are driven to open and close at the required timing by swinging 44e.

In addition, cam chain chambers 14c, 15c, and 20c are formed as a single cavity on the left side of the cylinder block 14, cylinder head 15, and head cover 20 (see FIG. 4), and the cam chain chambers 14c, 15c, and 20c As shown in FIG. 2, the front chain portion of the cam chain 37 spanned between the driving cam chain sprocket 36 and the upper driven cam chain sprocket 36 is slightly curved and extends vertically. The guide 38 is guided, and the rear rear part of the guide 38 is brought into contact with the tension slipper 39 which is curved in an arcuate shape to maintain an appropriate tension on the cam chain 37.
The tension slipper 39 is pressed behind by a tensioner lifter 39t.

FIG. 6 shows an exploded perspective view of the valve camshaft 41, the steady cam member 42, and the variable cam member 50 that are pivotally supported by the camshaft holder 16 in the left-right direction.
The valve camshaft 41 is a cylindrical member having a central shaft hole 41h. A spline forming portion 41c having a maximum outer diameter is formed at the center in the axial direction with six spline grooves 41cs. A cam fixing portion 41r having a reduced diameter is formed on the right side of the forming portion 41c via a stepped portion, and a journal portion 41j having a further reduced diameter is formed at the right end.
On the other hand, on the left side of the spline forming portion 41c, a left cylindrical portion 41l having a slightly reduced diameter is formed.

In the spline forming portion 41c of the valve camshaft 41, a pair of elongated holes 41s, 41s elongated in the axial direction are formed at the symmetrical positions on the spline grooves 41cs, 41cs at the symmetrical positions.
The pair of long holes 41 s and 41 s are formed at predetermined positions in the axial direction of the valve camshaft 41 with a predetermined length.
A keyway 41k is formed at the left end of the valve camshaft 41.
The valve camshaft 41 is accurately formed by cold forging.
For example, the spline groove 41cs is formed by cold forging and no post-processing is required.

A steady cam member 42 is press-fitted and fixed at a predetermined relative angle to the cam fixing portion 41r of the valve operating cam shaft 41.
The steady cam member 42 is press-fitted into the cam fixing portion 41r of the valve operating camshaft 41 with the exhaust cam lobe 42e on the left side and the intake cam lobe 42i on the right side until it comes into contact with the spline forming portion 41c from the right side. Are integrated adjacent to the spline forming portion 41c.

As described above, the steady cam member 42 is integrally fitted on the valve operating cam shaft 41 with the cam fixing portion 41r, and the variable cam member 50 is spline-fitted with the spline forming portion 41c.
Referring to FIG. 6, the variable cam member 50 has six spline protrusions 50cs which are fitted on the six spline grooves 41cs of the spline forming portion 41c of the valve camshaft 41 on the inner peripheral surface. On the outer peripheral surface, a variable cam lobe 50e is formed on the right side.
The variable cam lobe 50e has a base circle whose outer periphery is mostly the same diameter as or slightly smaller than the base circle of the exhaust cam lobe 42e, and a cam crest having a small lift amount protrudes in part.

A pair of pin holes 50p, 50p are formed symmetrically with the thick spline protrusions 50cs, 50cs at a symmetrical position perpendicular to the central axis in the cylindrical portion of the variable cam member 50 other than the variable cam lobe 50e. , 50p, an outer peripheral groove 50v passing through the outer opening is formed on the outer peripheral surface.
The pin holes 50p, 50p have a phase angle of about 90 degrees with the cam crest of the variable cam lobe 50e (see FIG. 8).

  When this variable cam member 50 is spline-fitted to the spline forming portion 41c of the valve camshaft 41 with the variable cam lobe 50e from the left side at a predetermined relative angle, the pin holes 50p and 50p of the variable cam member 50 are valve-operated. It corresponds to the long holes 41s and 41s of the cam shaft 41.

  Referring to FIG. 7, a bearing 46 is fitted to the right end journal portion 41j protruding to the right side of the cam fixing portion 41r into which the steady cam member 42 is press-fitted in the valve camshaft 41, and the variable cam member 50 is splined. A bearing 45 is inserted into the left cylindrical portion 41l on the left side of the fitted spline forming portion 41c, and a flange member 47 is press-fitted at a predetermined relative angle via a key 49 so that the bearing 45 is connected to the spline forming portion 41c. Sandwiched between.

In the flange member 47, the left side portion of the cylindrical portion swells symmetrically in the centrifugal direction to form flange portions 47f and 47f. A screw hole is formed in each of the pair of flange portions 47f and 47f that are rhombic in the axial direction. 47h and 47h are perforated.
In the driven cam chain sprocket 36, the center circular hole 36c is fitted to the left end exposed to the left of the flange member 47 of the valve drive cam shaft 41, and the mounting holes 36h and 36h provided at symmetrical positions are fitted to the flange member 47. The screws 48 and 48 are threaded through and screwed together with the screw holes 47h and 47h to be fixed to the flange member 47 (see FIG. 4).

A slide rod 53 of a slider mechanism 52 that slides and displaces the variable cam member 50 is fitted into the central shaft hole 41h of the valve camshaft 41 so as to be slidable in the left-right axis direction.
The slide rod 53 is slightly reduced in diameter on both sides of the central large-diameter portion 53c, and a pin hole 53p is formed in the central large-diameter portion perpendicular to the axial direction (see FIG. 7).

The slide rod 53 is inserted into the central shaft hole 41h of the valve camshaft 41, and the pin hole 53p is matched with the long holes 41s and 41s of the valve camshaft 41 and the pin holes 50p and 50p of the variable cam member 50. One connecting pin 54 is inserted into the pin holes 50p and 50p, the long holes 41s and 41s, and the pin hole 53p.
The connecting pin 54 is shorter than the inner diameter of the outer peripheral groove 50v of the variable cam member 50, and is prevented from coming off by a retaining ring 55 fitted in the outer peripheral groove 50v, and both ends of the connecting pin 54 are pin holes 50p, 50p of the variable cam member 50. To move together with the variable cam member 50.

Therefore, when the slide rod 53 is slid in the left and right axial directions within the central shaft hole 41 h, the connecting pin 54 is guided and moved together by the long holes 41 s and 41 s of the valve camshaft 41, and is integrated with the connecting pin 54. The variable cam member 50 moves in the axial direction and is displaced.
Since the valve camshaft 41 includes the steady cam member 42 as a separate member, the spline groove 41cs of the spline forming portion 41c into which the variable cam member 50 of the valve camshaft 41 is slidably fitted is provided in the steady cam member. Processing can be performed until just before 42 is arranged, and sliding by spline fitting of the variable cam member (50) can be made smooth.

  Since the connecting pin 54 can move between the left and right elongated ends of the long holes 41s, 41s formed at predetermined positions in the axial direction of the valve camshaft 41, the variable cam member 50 relative to the valve camshaft 41 can be moved. The sliding displacement in the axial direction is regulated by the long holes 41s and 41s.

When the variable cam member 50 is slid in the axial direction by the slide rod 53 via the connection pin 54, the connection pin 54 receives a force at the center and acts equally on the variable cam member 50 at both ends. The sliding of the variable cam member 50 can be made smooth by preventing the tilting.
The connecting pin 54 engages both ends of the even-numbered (six-thick) thick spline protrusion 50cs of the variable cam member 50 and the opposing spline protrusion 50cs without increasing the variable cam member 50 in the radial direction. Engagement between the connecting pin 54 and the variable cam member 50 can be ensured by increasing the engagement margin at the spline protrusion 50cs.

Referring to FIG. 8, the pin hole 50p of the variable cam member 50 relative to the straight line connecting the apex of the cam nose of the shaft center and the variable cam member 50 of the valve operating cam shaft 41, the connecting pin 54 engaging the opposite ends 50p The relative phase angle θ in the pointing direction is approximately 90 degrees.
Therefore, the connecting pin 54 that engages the variable cam member 50 receives the reaction force when the cam crest formed at the axial end of the variable cam member 50 acts on the valve substantially equally at both ends. It can be prevented that stress is biased at the engaging portion at one end and the smooth sliding of the variable cam member 50 is prevented.
Since the EGR variable cam lobe 50e has a small lift amount and a small cam crest, the load on the spline due to the force acting on the cam crest is small, and the variable cam member 50 can be reduced in size and weight. 50 sliding can be made better.

A female screw is engraved on the inner peripheral surface of the right end of the central shaft hole 41h of the valve camshaft 41, a coil spring 56 is inserted into the central shaft hole 41h from the right, and the flanged bolt 57 is screwed into the female screw. The spring 56 is sandwiched between the central large-diameter portion 53c of the slide rod 53 and the flanged bolt 57 to urge the slide rod 53 to the left, and the connecting pin 54 abuts the left long end of the long hole 41s. The slide rod 53 is regulated at the position, and the left end of the slide rod 53 protrudes leftward from the valve operating cam shaft 41.
Thus, the slider mechanism 52 that displaces the variable cam member 50 in the axial direction is configured.

With respect to the valve camshaft 41, the variable cam member 50 has an extremely high relative positional accuracy in the rotational direction due to the spline fitting of the six spline grooves 41cs and the spline protrusions 50cs.
Thus, since the relative position accuracy of the variable cam member 50 in the rotational direction with respect to the valve camshaft 41 is high due to the spline fitting, the circumferential width (rotation) of the long hole 41s of the valve camshaft 41 through which the connecting pin 54 penetrates. The processing accuracy of (direction width) can be lowered, and the workability can be improved.
The axial position of the variable cam member 50 with respect to the valve camshaft 41 is accurately regulated by the left and right long ends of the long hole 41s of the valve camshaft 41 so that the shaft of the variable cam member (50) can be controlled. The positional accuracy in the direction can be made good.

As described above, the slider mechanism 52 is configured in the central shaft hole 41h of the valve camshaft 41, and the stationary cam member 42, the variable cam member 50, the driven cam chain sprocket 36, and the bearing 45 are provided on the outer periphery of the valve camshaft 41. 46 is inserted into the shaft hole of the left and right bearing walls 16L and 16R projecting opposite to the left and right of the camshaft holder 16 with the outer assembly 46 fitted, and the right bearing 46 is inserted into the shaft hole of the right bearing wall 16R. And the left bearing 45 is fitted into the shaft hole of the left bearing wall 16L, and the valve camshaft 41 is rotatably supported by the camshaft holder 16 via bearings 45 and 46, so that the steady cam It rotates with the variable cam member 50 integrally with the member 42 (refer FIG. 4, FIG. 10).
The right bearing 46 is positioned in contact with the stepped portion of the right bearing wall 16R, and the left bearing 45 is positioned on the left side by a stop plate 59 fixed to the left bearing wall 16L by a bolt 58, so that the left bearing 45 is removed. This is prevented (see FIG. 4).

Referring to FIG. 4, when the slide rod 53 urged to the left by the coil spring 56 is pushed to the right against the urging force of the coil spring 56, as shown by the solid line in FIG. The variable cam member 50 is slid to the right via the pin 54, and the variable cam member 50 is restricted to a position where the connecting pin 54 contacts the right long end of the long hole 41s. Is adjacent to the exhaust cam lobe 42e on the left side of the stationary cam member 42 with a slight gap, and the roller 44er of the exhaust rocker arm 44e is in contact with both the exhaust cam lobe 42e and the variable cam lobe 50e. In addition to the normal opening / closing timing of the exhaust valve 34, the exhaust valve 34 is opened / closed by the variable cam lobe 50e.
The opening / closing of the exhaust valve 34 by the variable cam lobe 50e executes EGR (exhaust gas recirculation).

  On the other hand, when the slide rod 53 is moved to the left by the coil spring 56, the variable cam member 50 is slid to the left via the connecting pin 54 as shown by a two-dot chain line in FIG. When the distance is greater than a predetermined distance, the roller 44er of the exhaust rocker arm 44e does not contact the variable cam lobe 50e, but only the exhaust cam lobe 42e, and the exhaust valve 34 opens and closes at the normal exhaust valve timing.

A variable valve timing drive mechanism 60 that projects to the left from the valve camshaft 41 and presses the left end of the slide rod 53 biased to the left by the coil spring 56 to the right to drive the slider mechanism 52 is a driven cam chain sprocket It is provided on the left side of 36 (see FIG. 4).
The variable valve timing drive mechanism 60 includes an electromagnetic solenoid 61 as an actuator and a swing arm 65 that transmits the drive of the electromagnetic solenoid 61 to the slider mechanism 52. The electromagnetic solenoid 61 is fixed above the ceiling wall 20u of the head cover 20. The swing arm 65 is pivotally supported by the cam chain chamber 20c of the head cover 20 so as to be swingable.

  The head cover 20 has a substantially rectangular bowl shape with a ceiling wall 20u and a rectangular cylindrical peripheral wall 20s, and the center portion in the front-rear direction of the portion covering the cam chain chamber 20c of the ceiling wall 20u protrudes thickly upward. 21, and projecting boss portions 22, 22 are formed so as to project continuously on both front and rear sides of the central projecting portion 21.

The central protrusion 21 has a central gap 21c with a predetermined width at the center in the front-rear direction from the cam chain chamber 20c side, and a circular hole 21h drilled to the left from the right side surface of the central protrusion 21 is the center. The gap 21c is reached.
An internal thread is engraved on the protruding boss portions 22 and 22 from the right side surface.

A plunger 61p protrudes from a mounting cylindrical portion 62b protruding from one end face of the columnar body of the electromagnetic solenoid 61 so as to be able to protrude and retract.
From the main body of the electromagnetic solenoid 61, mounting flange portions 62f and 62f extend forward and backward.
The electromagnetic solenoid 61 is attached to the central protrusion 21 from the right side with the plunger 61p on the left side.

  At that time, referring to FIG. 11, the mounting cylindrical portion 62 b of the electromagnetic solenoid 61 is fitted into the circular hole 21 h of the central projecting portion 21, and the mounting flange portions 62 f and 62 f extending forward and backward from the main body of the electromagnetic solenoid 61 are provided. The bolts 63 and 63 are brought into contact with the protruding boss portions 22 and 22, pass through the mounting flange portions 62 f and 62 f and are screwed into the female threads of the protruding boss portions 22 and 22, and the electromagnetic solenoid 61 is connected to the ceiling wall 20 u of the head cover 20. It is fixed above.

In the electromagnetic solenoid 61 attached in this way, the axial direction in which the plunger 61p moves is parallel to the axial direction in which the valve operating cam shaft 41 and the slide rod 53 in the central shaft hole 41h slide.
The plunger 61p of the electromagnetic solenoid 61 is in a position where the slide rod 53 is translated in the cylinder axis direction which is the central axis of the cylinder 14a.

As shown in FIG. 12, a plurality of ribs are formed on the inner surface of the head cover 20, and a pair of guide walls 23, 23 are symmetrically provided on the front and rear sides of the central gap 21 c drilled in the central protrusion 21. It is formed to extend.
Referring to the cross-sectional view of FIG. 13, the guide walls 23, 23 have end faces 23a, 23a along the front and rear side faces 21a, 21a facing each other across the central gap 21c, and extend in the front-rear direction and slant in the middle. Bends leftward and expands.

The front and rear side surfaces 21a and 21a constituting the central gap 21c and the end surfaces 23a and 23a of the front and rear guide walls 23 and 23 are the same surface.
Further, pivot holes 21b and 21b are formed coaxially at predetermined positions on the front and rear side surfaces 21a and 21a constituting the central gap 21c.

  On the other hand, as shown in FIG. 9, the swing arm 65 is a straight bar-shaped arm having a U-shaped cross section in which long and parallel side plate portions 65b and 65b facing each other are connected by a long connecting plate portion 65a. It is a member and is arranged in the cam chain chamber 20c of the head cover 20 so as to be oriented substantially parallel (substantially in the vertical direction) to the cylinder axis direction. The side plate portions 65b and 65b oriented in the substantially vertical direction are arranged from the center. The shaft support holes 65bh and 65bh are coaxially arranged at a position offset to the upper part, and are respectively tapered in the vertical direction from the portions of the shaft support holes 65bh and 65bh.

  The swing arm 65 is disposed along the left surface of the driven cam chain sprocket 36 in the cam chain chamber 20c with the connecting plate portion 65a directed to the right and the opening directed to the left. However, in this case, the substantially upper half of the swing arm 65 is inserted into the central gap 21c of the central protrusion 21, and the pivot holes 65bh and 65bh are pivot holes 21b formed in the front and rear side surfaces 21a and 21a of the central gap 21c. , 21b, and the pivot bolt 64 screwed into the pivot hole 21b from the front projecting boss portion 22 passes through the pivot support holes 65bh, 65bh of the swing arm 65 and the pivot shaft of the rear projecting boss portion 22 The swing arm 65 is pivotally supported by the pivot bolt 64 so as to swing freely.

The swing arm 65 swings so that the upper half portion is sandwiched between the front and rear side surfaces 21a and 21a constituting the central gap 21c, and the lower half portion is the front and rear guide walls 23 and 23 that are flush with the front and rear side surfaces 21a and 21a. It is guided so as to be sandwiched between the end faces 23a, 23a, and smoothly swings without causing a torsion in the torsional direction.
Referring to FIG. 4, the slide rod 53 that slides in the central shaft hole 41 h of the valve camshaft 41 is substantially the same as the mating surface S of the head cover 20 and the cylinder head 15 (the lower surface of the elastic seal member 18). They are on the same plane, and the lower end of the swing arm 65 slightly protrudes below the mating surface S of the head cover 20 and the cylinder head 15.

  Since the swing arm 65 is pivotally supported by a pivot bolt 64 at a position offset from the center to the top, the lower portion is longer than the upper portion of the pivot bolt 64. As shown in FIG. The pivot bolt 64 serving as the fulcrum P of the moving arm 65 is positioned above the driven cam chain sprocket 36 fixed to the valve camshaft 41, and the head cover is attached to the connecting plate portion 65a at the upper end of the pivot bolt 64. The plunger 61p protruding leftward from the mounting cylindrical portion 62b of the electromagnetic solenoid 61 fixed above the ceiling wall 20u of the 20 is in contact with the valve driving camshaft 41 on the connecting plate portion 65a at the lower end of the pivot bolt 64. The slide rod 53 that protrudes further to the left and is biased by the coil spring 56 comes into contact.

Referring to FIG. 4, the straight bar-like swing arm 65 has a force point Q at the upper point where the plunger 61p of the electromagnetic solenoid 61 abuts, where the swing center of the swing arm 65 by the pivot bolt 64 is the fulcrum P. Yes, the lower end point that contacts the slide rod 53 is the action point R, and the swing arm 65 receives the plunger 61p protruding leftward by the excitation drive of the electromagnetic solenoid 61 at the upper end force point Q, and swings to the lower end. The point of action R acts on the slide rod 53 and slides the slide rod 53 to the right against the urging force of the coil spring 56.
When the electromagnetic solenoid 61 is demagnetized, the slide rod 53 slides to the left by the urging force of the coil spring 56, swings the swing arm 65, and the plunger 61p is pushed to the right.

  That is, when the electromagnetic solenoid 61 is demagnetized, the slide rod 53 slides to the left by the urging force of the coil spring 56, and the variable cam is connected via the connecting pin 54 as shown by a two-dot chain line in FIG. The member 50 slides to the left and moves away from the steady cam member 42, and the exhaust valve 34 opens and closes at normal exhaust valve timing.

When the electromagnetic solenoid 61 is energized, the plunger 61p protrudes to the left, and the swing arm 65 swings until the connecting pin 54 comes into contact with the right long end of the long hole 41s of the valve camshaft 41. 53 slides to the right against the urging force of the coil spring 56, and as shown by the solid line in FIG. Apart from the normal opening / closing timing of the exhaust valve 34 by the exhaust cam lobe 42e, the exhaust valve 34 is opened / closed by the variable cam lobe 50e.

The opening / closing timing of the exhaust valve 34 different from the normal exhaust timing is executed at a predetermined timing overlapping the opening timing of the intake valve 33, and the exhaust gas remaining in the exhaust passage by the opening of the exhaust valve 34 is removed from the combustion chamber. It is possible to realize so-called EGR (exhaust gas recirculation) for returning to 15z and for combustion.
That is, the EGR device is configured by the variable valve timing drive mechanism 60, the slider mechanism 52, and the variable cam member 50, and this EGR device is configured with a simple structure without requiring a special dedicated EGR valve or EGR port. be able to.

  A slider mechanism 52 is slidably inserted in the central shaft hole 41h of the valve camshaft 41 and is slid by driving of the electromagnetic solenoid 61. The slider cam 52 is formed in the valve camshaft 41 in the axial direction. Since the connecting pin 54 that connects the slide rod 53 and the variable cam member 50 through the elongated hole 41s is provided, a simple slider mechanism 52 with a small number of parts is provided inside the valve camshaft (41). The variable valve timing valve operating apparatus can be reduced in size and cost.

In the swing arm 65, the distance PR from the fulcrum P to the action point R is longer than the distance PQ from the fulcrum P to the force point Q, and the lever ratio r (= PR /) is the ratio of the distance PR to the distance PQ as a lever. PQ) is large.
The swing arm 65 is disposed such that its longitudinal direction is substantially parallel to the cylinder axis direction (substantially in the vertical direction), and the fulcrum P of the swing arm 65 is fixed to the valve camshaft 41. Since it is positioned above the sprocket 36, the swing arm 65 can be compactly incorporated into the valve operating apparatus while the lever ratio r is increased.
Since the head cover 20 supports the swing shaft 64 and integrally forms the pair of guide walls 23, 23, a simple structure with a reduced number of parts can be achieved.

The head cover 20 having a generally rectangular bowl shape is formed with mounting bosses 20b and 20b for attaching the head cover 20 to the cylinder head 15 with flanged bolts 70 so as to be offset from each other on the front and rear of the ceiling wall 20u (FIG. 11). 12), on the back surface of the head cover 20, a groove 20v into which the elastic seal member 18 is fitted is formed on the end surface of the peripheral wall 20s, as shown in FIG. Knock holes 20n, 20n are formed.
As shown in FIG. 10, mounting bolt holes 15b, 15b and knock holes 15n, 15n corresponding to the mounting boss portions 20b, 20b and knock holes 20n, 20n of the head cover 20 are formed on the upper surface of the cylinder head 15. ing.

Further, the head cover 20 is formed with a protrusion 25 having an oil passage 26 therein, which extends in a straight line slightly diagonally in the front-rear direction at a position slightly to the right on the back surface of the ceiling wall 20u.
The rear end of the ridge 25 reaches the peripheral wall 20s, the oil passage 26 has a front end reaching the center of the front half of the ceiling wall 20u, and injection holes 27 communicating with the oil passage 26 at four predetermined locations of the ridge 25 are provided. It is drilled downward.

As shown in FIG. 10, a head cover 20 in which an elastic seal member 18 is fitted in a groove 20v on an end surface of a peripheral wall 20s is mounted on a cylinder head 15 in which a cylindrical knock member 72 is fitted in knock holes 15n, 15n on the upper surface. At that time, the head cover 20 is positioned and overlapped so that the knock member 72 fits into the knock holes 20n, 20n of the head cover 20 (see FIG. 12), and the coaxial mounting bolt hole 15b and mounting boss portion The head cover 20 is mounted on the cylinder head 15 by passing the flanged bolt 70 through 20b and tightening it through the elastic member 71 (see FIG. 3).
Therefore, the head cover 20 is elastically supported by the cylinder head 15 via the elastic seal member 18 and the elastic member 71.

Since the head cover 20 is elastically supported by the cylinder head 15 and the shift in the direction perpendicular to the cylinder axis is restricted by the knock member 72, the head cover 20 may affect the swing of the swing arm 65 pivotally supported on the head cover 20 side. The vibration on the internal combustion engine main body side is absorbed by the elastic support, and the displacement of the relative positional relationship between the swing arm 65 and the slide rod 53 in contact therewith can be prevented by the displacement restriction by the knock member.
Therefore, the swing of the swing arm 65 can be stably transmitted to the slide rod 53 without shifting, and the displacement displacement of the variable cam member 50 by the drive of the electromagnetic solenoid 61 is always performed accurately, and the EGR execution timing Can be executed with high accuracy.

The knock hole 15n on the rear side of the cylinder head 15 communicates with an oil supply path extending from the cylinder block 14 side, and the corresponding knock hole 20n of the head cover 20 is also connected to the oil supply path 28 as shown in FIG. Since the oil supply passage 15a on the cylinder head 15 side communicates with the oil passage 26 of the head cover 20 by the cylindrical knock member 72, the oil is supplied to the oil passage 26. .
The knock member 72 also serves as a seal for the oil connecting portion.

  As shown by the phantom line (two-dot chain line) in FIG. 10, the oil passage 26 extends obliquely in the front-rear direction above the intake rocker arm 44i and the exhaust rocker arm 44e, and from four injection holes 27 drilled in the middle thereof. The injected oil is sprayed on the intake rocker arm 44i and the exhaust rocker arm 44e and used for lubricating the valve operating mechanism 40.

When the head cover 20 is mounted on the cylinder head 15, the head cover 20 is mounted in a small assembly state in which the swing arm 65 of the variable valve timing drive mechanism 60 is incorporated in the cylinder head 15.
Since the lower end of the swing arm 65 protrudes downward from the head cover 20 in a state where the swing arm 65 is assembled to the head cover 20, the swing arm 65 is placed when the head cover 20 is put on the cylinder head 15 from above. Easy to check the position of the lower end of the swing arm 65 from the side so that the lower end of the swing arm does not come into contact with the slide rod 53 protruding leftward from the valve camshaft 41 provided on the cylinder head 15 side. It can be assembled in a good manner.

Thereafter, the electromagnetic solenoid 61 is attached to the central projecting portion 21 of the head cover 20 from the right side above the ceiling wall 20u of the head cover 20.
When the mounting cylindrical portion 62b of the electromagnetic solenoid 61 is inserted into the circular hole 21h of the central projecting portion 21, the plunger 61p retracted in the demagnetized state of the electromagnetic solenoid 61 abuts against the upper end of the swing arm 65 to push and swing. The lower end of the swing arm 65 is in a state indicated by a two-dot chain line in FIG. 4 which is in contact with the left end of the slide rod 53 biased by the coil spring 56 and slightly pressed.
That is, the swing arm 65 is in a state where the lower end is urged by the coil spring 56 via the slide rod 53, and does not swing freely.

  Therefore, even if the plunger 61p is advanced and retracted by driving the electromagnetic solenoid 61, the plunger 61p and the upper end of the swing arm 65 are always kept in contact with each other, and the lower end of the swing arm 65 and the slide rod 53 are always in contact with each other. Since power is transmitted to the slide rod 53 in a state where is maintained, no sound is generated due to collision, and noise can be prevented.

When the head cover 20 is attached to the cylinder head 15 by screwing the flanged bolt 70, the left end of the slide rod 53 urged to the left by the coil spring 56 abuts against and presses the lower end of the swing arm 65, and swings. The upper end of the moving arm 65 is in contact with the left end of the plunger 61p with the electromagnetic solenoid 61 retracted (see the two-dot chain line in FIG. 4).
At this time, as shown by a two-dot chain line in FIG. 4, the slide rod 53 slides to the left, displaces the variable cam member 50 to the left via the connecting pin 54, and leaves the steady cam member 42 to exhaust. The roller 44er of the rocker arm 44e contacts only the exhaust cam lobe 42e, and the exhaust valve 34 opens and closes at normal exhaust valve timing.

  When the electromagnetic solenoid 61 is driven and the plunger 61p protrudes to the left, the swing arm 65 swings by receiving the force at the upper end force point Q as shown by the solid line in FIG. The slide rod 53 is pushed to the right against the urging force of the coil spring 56, and the variable cam member 50 is slid to the right via the connecting pin 54 and close to the exhaust cam lobe 42e on the left side of the steady cam member 42. The roller 44er of the exhaust rocker arm 44e is in contact with both the exhaust cam lobe 42e and the variable cam lobe 50e so that the exhaust valve 34 of the variable cam lobe 50e is separated from the normal opening / closing timing of the exhaust valve 34 by the exhaust cam lobe 42e. By opening and closing, EGR (exhaust gas recirculation) is executed.

  When the solenoid rod 61 is driven and the slide rod 53 is pushed rightward through the swing of the swing arm 65, the connecting pin 54 moves the variable cam member 50 together with the slide rod 53. The variable cam member 50 stops at a close position slightly away from the steady cam member 42 by being regulated by contacting the right long end of the long hole 41s of the 41.

  The oil sprayed from the injection hole 27 of the lubricating oil passage 26 formed in the ceiling wall 20u of the head cover 20 to the valve mechanism 40 is splined to the valve camshaft 41 on which the variable cam member 50 slides. Since the joint portion is also lubricated, oil enters the gap between the variable cam member 50 and the steady cam member 42, but the variable cam member 50 is not in contact with the steady cam member 42 but is in the gap. have.

  When the variable cam member 50 is in contact with the steady cam member 42, the variable cam member 50 sticks to the steady cam member 42 due to oil viscosity, and the variable cam member 50 is released from the steady cam member 42 to release the EGR. However, there is a problem that the movement of the variable cam member 50 is delayed. However, the movement of the connecting pin 54 abuts against the right long end of the long hole 41s of the valve camshaft 41 to restrict the movement, so that the variable cam member 50 However, since there is a gap close to the stationary cam member 42, there is no such inconvenience and the accuracy of the EGR execution timing can be maintained satisfactorily.

  In addition to restricting sliding of the variable cam member 50 by connecting the connecting pin 54 integral with the slide rod 53 to the long end of the long hole 41s formed in the valve camshaft 41, the swing arm By restricting the swing of 65, the variable cam member 50 may be stopped in proximity to the stationary cam member 42 with a gap.

Furthermore, only the peripheral edge portion of the shaft hole of the right end surface of the cylindrical variable cam member 50 facing the steady cam member 42 is slightly protruded in the axial direction, and the protruding peripheral edge portion of the shaft hole contacts the steady cam member 42. The movement of the variable cam member 50 may be regulated in contact therewith.
In this case, when the variable cam lobe 50e comes into contact with the steady cam member 42, only the peripheral edge portion of the shaft hole comes into contact with the steady cam member 42 to reduce the contact area, and the variable cam member 50 is stuck to the steady cam member 42 due to oil viscosity. The sticking is weak, and when the variable cam member 50 moves away from the steady cam member 42 and releases the EGR, there is no problem that the movement of the variable cam member 50 is delayed.

The oil sprayed from the injection hole 27 of the oil passage 26 in the ceiling wall 20u of the head cover 20 to the valve mechanism 40 and the oil swept up by the cam chain 37 are caused by the rocker arms 44i and 44e as the valve cam shaft 41 rotates. The driven cam chain sprocket 36 of the guide walls 23 and 23 that guides the swing arm 65 from both sides by being swung up and scattered by the swing and rotation of the driven cam chain sprocket 36 and the rotation of the cam chain 37. It also adheres to the right wall surface on the side and the outer plate surface (right plate surface) of the connecting plate portion 65 a of the swing arm 65 and flows down along the right wall surface of the guide walls 23, 23 and the right plate surface of the swing arm 65.
This oil also enters the gap between the swinging portion of the swinging arm 65 and the guide walls 23, 23, so that the swinging of the swinging arm 65 is smooth.

  As shown in FIGS. 4 and 5, the guide walls 23, 23 have a lower end on the swing arm 65 side, the lower end thereof is above the slide rod 53, and the axial direction in which the operating point R of the swing arm 65 moves. The oil flowing down the right wall surface of the guide walls 23, 23 is guided toward the swing arm 65 along the lower ends of the guide walls 23, 23 and crosses the gap between them to the swing arm 65. Since the oil has flowed down along the swing arm 65 and reaches the lower end of the lower swing arm 65, it is supplied to the operating point R of the swing arm 65, that is, the contact portion of the slide rod 53, Wear of the pressing action point of the swing arm 65 can be prevented.

Next, a variable valve timing valve operating apparatus according to another embodiment will be described with reference to FIGS.
The valve operating cam shaft 141 of the present variable valve timing valve operating apparatus is a cylindrical member having a central shaft hole 141h substantially the same as the valve operating cam shaft 41 of the above embodiment, but a steady cam portion 142 is integrally formed. And the spline forming portion 141c and the spigot outer peripheral portion 141i that are fitted in the spigot simultaneously with the variable cam member 150 are formed.

That is, with reference to FIG. 18 and FIG. 19, the main valve camshaft 141 is formed with a spline forming portion 141c and a spigot outer peripheral surface portion 141i arranged side by side at the center in the axial direction. The part 142 is integrally formed.
The valve camshaft 141 projects a journal portion 141j having a reduced diameter on the right side of the steady cam portion 142, while a left cylindrical portion 141l having a slightly reduced diameter is formed on the left side of the spline forming portion 141c. .

Four wide spline grooves 141cs are formed in the spline forming portion 141c of the valve camshaft 141, and the outer circumferential surface portion 141i of the spigot outer peripheral surface portion 141i is formed with a circumferential surface having an outer diameter slightly larger than the maximum outer diameter of the spline forming portion 141c. ing.
The steady cam portion 142 of the valve camshaft 141 has the same cam shape as the steady cam member 42, and an exhaust cam lobe 142e is formed on the left side and an intake cam lobe 142i is formed on the right side.

Then, a long hole 141s is drilled at a predetermined position perpendicularly to the axial direction from the wide spline groove 141cs of the spline forming portion 141c to the spigot outer peripheral surface portion 141i.
The long hole 141s has a wide circumferential width slightly smaller than the width of the wide spline groove 141cs.
A keyway 141k is formed at the left end of the valve camshaft 41.
The valve camshaft 141 is integrally formed with high accuracy by cold forging including the steady cam portion 142.

The variable cam member 150 slidably fitted to the valve camshaft 141 has an inlay corresponding to the four spline grooves 141cs of the spigot outer peripheral surface portion 141i of the valve camshaft 41 and the spline forming portion 141c on the inner peripheral surface. An inner peripheral surface portion 150i and four spline protrusions 150cs are formed.
A variable cam lobe 150e is formed on the right side of the outer peripheral surface of the variable cam member 150. The variable cam lobe 150e is a cam lobe for EGR, and most of the base circle has the same diameter as the exhaust cam lobe 142e or a slightly smaller diameter. None, a small cam crest with a small lift amount protrudes in part.

  A pair of pin holes 150p, 150p are formed at symmetrical positions perpendicular to the central axis at a phase angle with the spline protrusion 150cs in the circumferential direction of the inner spigot inner circumferential surface portion 150i in the axial direction of the variable cam member 150. An outer peripheral groove 150v passing through the outer openings of the holes 150p and 150p is formed on the outer peripheral surface.

The variable cam member 150 is inserted into the valve camshaft 141 from the left side, and is spline-fitted simultaneously with the spigot outer peripheral surface portion 141i of the valve camshaft 141 and the spline forming portion 141c.
When the four spline protrusions 150cs are spline-fitted into the four spline grooves 141cs at a predetermined relative angle, the pin holes 150p, 150p of the variable cam member 150 coincide with the long holes 141s of the valve camshaft 141.
However, the circumferential width of the long hole 141s is larger than the inner diameter of the pin hole 150p.

  Referring to FIG. 16, a bearing 146 is fitted to the right end journal portion 141j of the valve camshaft 141, and a bearing 145 is fitted to the left cylindrical portion 141l on the left side of the spline forming portion 141c to which the variable cam member is fitted. Further, the flange member 147 is press-fitted at a predetermined relative angle via the key 149 to sandwich the bearing 145 with the spline forming portion 141c, and the driven cam chain sprocket 136 is screwed into the screws 148, 148. It is fixed by.

A slide rod 153 of a slider mechanism 152 that slides and displaces the variable cam member 150 is fitted into the central shaft hole 141h of the valve camshaft 141 so as to be slidable in the left-right axis direction.
The slide rod 53 is slightly reduced in diameter on both sides of the central large diameter portion 153c, and a pin hole 153p is formed in the central large diameter portion perpendicular to the axial direction (see FIG. 16).

The slide rod 153 is inserted into the central shaft hole 141h of the valve camshaft 141, the pin hole 153p is matched with the long hole 141s of the valve camshaft 141 and the pin holes 150p and 150p of the variable cam member 150, and the matched pins One connecting pin 154 is inserted into the holes 150p and 150p, the long holes 141s and 141s, and the pin hole 153p.
The connecting pin 154 is shorter than the inner diameter of the outer peripheral groove 150v of the variable cam member 150, and is prevented from coming off by a retaining ring 155 fitted in the outer peripheral groove 150v, and both ends of the connecting pin 154 are pin holes 150p, 150p of the variable cam member 150. To move together with the variable cam member 150.

Therefore, when the slide rod 153 is slid in the left and right axial directions within the central shaft hole 141h, the connecting pin 154 moves together while being regulated by the long holes 141s and 141s of the valve camshaft 41, and is integrated with the connecting pin 154. The variable cam member 150 moves in the axial direction and is displaced.
When the electromagnetic solenoid 61 is driven, the slide rod 53 is slid through the swing of the swing arm 65, and the variable cam member 150 is slid to the right through the connecting pin 154 and close to the exhaust cam lobe 142e. In addition to the normal opening and closing timing of the exhaust valve 34 by the exhaust cam lobe 142e, the exhaust valve 34 is opened and closed by the variable cam lobe 150e, and EGR (exhaust gas recirculation) is executed.

  Since the steady cam portion 142 and the spline portion 141c are integrally formed by cold forging in the valve train cam shaft 141, the cam phase and lift amount of the steady cam portion 142 are reduced while reducing the number of processing steps for the valve train cam shaft 141. The accuracy of the axial position and the like can be improved.

  Since the variable cam member 150 is spline-fitted to the outer periphery of the valve camshaft 141 at the same time as the spigot fitting, the coaxiality of the variable cam member 150 with respect to the valve camshaft 141 is ensured with high accuracy by the spigot fitting. In spline fitting, it is only necessary to ensure the positioning of the variable cam member 150 in the rotational direction with respect to the valve camshaft 141 without considering the coaxiality, and therefore the machining accuracy of the spline groove 41cs and spline protrusion 50cs is set to be so high. There is no need, and cost reduction can be achieved.

  Since the connecting pin 154 engages with the inner surface portion 150i of the inlay where the coaxial property of the variable cam member 150 is ensured, a force acts on the inner surface portion 150i of the inner surface via the connecting pin 154, and the variable cam portion 150 falls down. And can smoothly slide and displace while maintaining coaxiality.

40 ... Valve drive mechanism, 41 ... Valve drive cam shaft, 41s ... Long hole, 41h ... Center shaft hole, 41cs ... Spline groove, 42 ... Steady cam member, 42i ... Intake cam lobe, 42e ... Exhaust cam lobe, 44i ... Intake rocker arm 44e ... exhaust rocker arm, 43ir, 44er ... roller, 50 ... variable cam member, 50cs ... spline protrusion, 52 ... slider mechanism, 53 ... slide rod, 54 ... connecting pin, 56 ... coil spring,
60 ... Variable valve timing drive mechanism, 61 ... Electromagnetic solenoid, 62b ... Mounting cylinder, 62f ... Mounting flange, 63 ... Bolt, 64 ... Axial bolt, 65 ... Swing arm,
141 ... Valve cam shaft, 141s ... Long hole, 141i ... Inner outer peripheral surface portion, 141cs ... Spline groove, 142 ... Steady cam portion, 142i ... Intake cam lobe, 142e ... Exhaust cam lobe,
150 ... Variable cam member, 150i ... Inner inner peripheral surface part, 150cs ... Spline protrusion, 152 ... Slider mechanism, 153 ... Slide rod, 154 ... Connecting pin, 156 ... Coil spring.

Claims (8)

A valve-operated camshaft ( 141 ) that rotates in conjunction with the crankshaft of the internal combustion engine and opens and closes the intake valve (33) and the exhaust valve (34) by a stationary cam portion ( 142 ) of intake and exhaust;
A variable cam member ( 150 ) that is spline fitted to the outer periphery of the valve camshaft ( 141 ) and slidably displaced in the axial direction to change the valve timing;
In a variable valve timing valve operating apparatus comprising a slider mechanism ( 152 ) that slides and displaces the variable cam member ( 150 ) in the axial direction,
The slider mechanism ( 152 )
A slide rod ( 153 ) that is slidably inserted into a central shaft hole (141h ) of the valve camshaft ( 141 ) and slides under the action of an actuator (61);
The valve operating cam shaft long hole formed in an elongated axially (141) the slide rod penetrates the (141s) (153) and the variable cam member (150) connecting members for connecting the (154) And
Wherein the connecting member (154) on the long long end of the hole (141s) of the valve operating cam shaft (141) that abuts the sliding of the variable cam member (150) is configured to so that is regulated ,
The valve operating cam shaft (141), by cold forging, the variable valve timing valve operating system in which the stationary cam portion (142) and portions of said spline (141c) is characterized Rukoto integrally formed. A valve-operated camshaft (141) that rotates in conjunction with the crankshaft of the internal combustion engine and opens and closes the intake valve (33) and the exhaust valve (34) by a stationary cam portion (142) of intake and exhaust;
A variable cam member (150) that is spline fitted to the outer periphery of the valve camshaft (141) and slidably displaced in the axial direction to change the valve timing;
In a variable valve timing valve operating apparatus comprising a slider mechanism (152) that slides and displaces the variable cam member (150) in the axial direction,
The slider mechanism (152)
A slide rod (153) that is slidably inserted into the central shaft hole (141h) of the valve camshaft (141) and slides under the action of the actuator (61);
A connecting member (154) that connects the slide rod (153) and the variable cam member (150) through a long hole (141s) formed in the axial direction of the valve camshaft (141). And
The variable cam member (150) is simultaneously spigot fitting is spline fitted to the outer periphery of the valve operating cam shaft (141),
The valve operating cam shaft (141), by cold forging, the variable valve timing valve operating system in which the stationary cam portion (142) and portions of said spline (141c) is characterized Rukoto integrally formed. The variable cam member (50, 150) is disposed adjacent to the stationary cam portion (42, 142),
When the variable cam member (50, 150) is separated from the steady cam portion (42, 142) by a predetermined distance or more, the variable cam member (50, 150) does not act on the valve, and the variable cam member (50, 150) is not in the steady cam portion (42, 142). The variable valve timing valve operating device according to claim 1 or 2, wherein the variable cam member (50, 150) is configured to change the valve timing by acting on the valve when close to the valve. . The steady cam portion (42, 142) includes an exhaust cam lobe (42e, 142e),
The variable cam member (50, 150) is the exhaust cam lobe (42e, 142e) and wherein the configured to vary the exhaust valve timing to act on the to close the variable cam member (50, 150) the exhaust valve (34) The variable valve timing valve operating apparatus according to claim 3. The connecting member (54, 154) has a rod shape, vertically penetrates the slide rod (53, 153), and the elongated holes (41s, 141s) provided at opposite ends of the valve camshaft (41, 141). The variable valve timing valve operating device according to any one of claims 1 to 4 , wherein the variable cam timing member is engaged with the variable cam member (50, 150). The connecting members (54,154) are arranged in an angle direction of about 90 degrees with respect to a straight line connecting the shaft center of the valve cam shaft (41,141) and the top of the cam crest of the variable cam member (50,150). 6. The variable valve timing valve operating apparatus according to claim 5, wherein: The valve camshaft (41,141) and the variable cam member (50,150) are spline-fitted by fitting even-numbered spline grooves (41cs, 141cs) and spline protrusions (50cs, 150cs),
The variable valve timing according to any one of claims 1 to 6 , wherein the connecting member (54, 154) is engaged with a spline protrusion (50cs, 150cs) of the variable cam member (50, 150). Valve operating device.   The variable valve timing valve operating apparatus according to claim 2, wherein the connecting member (154) is engaged with an inner surface (150i) of an inlay of the variable cam member (150).

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