JP2021161951A - Variable valve device - Google Patents

Abstract

To provide a variable valve device capable of accurately determining valve operation characteristics at low costs.SOLUTION: In a variable valve device constituting a cam switching mechanism (70) for switching cam lobes (43A, 43B) in axially shifting a cam carrier (43) through switching pins (73, 74) by movement of a switching driving shaft (71), sensors (Sia, Sib) are disposed to detect states of a plurality of detected portions (71a, 71b) disposed on the switching driving shaft (71) respectively at prescribed positions, and valve operation characteristics determination means (100) discriminates whether or not results of detection by the plurality of sensors (Sia, Sib) change before and after the movement of the switching driving shaft (71), and determines valve operation characteristics from the movement state of the switching driving shaft (71).SELECTED DRAWING: Figure 10

Description

The present invention relates to a variable valve gear that switches the operating characteristics of a valve in an internal combustion engine.

An example of a variable valve gear that switches the cam lob acting on the rocker arm that drives the valve by moving the switching drive shaft and determines the valve operating characteristics by detecting the moving state of the switching drive shaft (for example). , Patent Document 1 etc.).

Japanese Unexamined Patent Publication No. 2011-196266

In the variable valve gear disclosed in Patent Document 1, a rocker shaft is arranged in parallel with a camshaft in which a plurality of camlobs having different cam profiles that determine valve operating characteristics are formed on the outer peripheral surface, and the rocker shaft has the same rocker shaft. The first rocker arm and the second rocker arm, which are swingably supported by the shaft, swing integrally with each other by moving the switching pin in one direction, and swing independently of each other by moving the switching pin in the other direction. By switching the cam lob that acts on the valve, the valve operating characteristics are switched.

A movement sensing sensor that detects the moving position of the link shaft (switching drive shaft) that moves the switching pin via the link arm is provided at a coaxial position facing the end of the link shaft.

The movement detection sensor is a magnetic sensor, detects a clearance between the link shaft and the link shaft, and determines the movement position of the link shaft based on whether the detected clearance is smaller or larger than a predetermined value as a discrimination reference.

As the movement detection sensor, an expensive one such as a magnetic sensor is used, and a means for discriminating the detection signal based on the discriminating standard is required, which increases the cost of the detection system.

The present invention has been made in view of this point, and an object of the present invention is to provide a variable valve gear capable of accurately determining valve operating characteristics at low cost.

In order to achieve the above object, the variable valve gear according to the present invention is
A camshaft rotatably provided on the cylinder head (3) of an internal combustion engine,
A cylindrical member that is slidably fitted in the axial direction with relative rotation prohibited on the outer periphery of the camshaft, and a plurality of camlobs having different cam profiles are formed on the outer peripheral surface adjacent to each other in the axial direction. , A cam carrier with a lead groove formed around the outer peripheral surface,
A switching pin that moves forward and backward so that it can be engaged and disengaged from the lead groove,
A switching drive shaft for driving the switching pin is provided.
The axial movement of the switching drive shaft advances and retreats the switching pin, and the lead groove in which the switching pin advances and engages causes the cam carrier to rotate and shift in the axial direction to act on the valve. In a variable valve gear that constitutes a cam switching mechanism that changes the valve operating characteristics by switching the cam lob.
A plurality of detected portions provided on the switching drive shaft apart from each other in the axial direction,
A sensor that detects the state of a plurality of the detected parts at predetermined positions, and
A valve operating characteristic determining means for determining the operating valve operating characteristic from the moving state of the switching drive shaft based on the detection results of the plurality of sensors, and a valve operating characteristic determining means.
With
The valve operating characteristic determination means is
Whether or not there is a change in the detection results of each of the plurality of sensors before and after the movement of the switching drive shaft is determined, and the valve operating characteristic during operation is determined from the moving state of the switching drive shaft. It is characterized by that.

According to this configuration, the valve operating characteristic determining means determines whether or not there is a change in the detection results of each of the plurality of sensors before and after the movement of the switching drive shaft, and the moving state of the switching drive shaft. Since the valve operating characteristics during operation are determined from the above, the shift of the cam carrier can be performed by determining the change in the detection results of the multiple sensors after the movement, taking into consideration the state during the movement of the switching drive shaft by the plurality of sensors. The moving state of the switching drive shaft can be determined to the extent that it can be determined whether or not it has been completed, and the valve operating characteristic during operation can be accurately determined from the moving state of the switching drive shaft.
Since the sensor detects whether or not there is a change in the detection result before and after the movement of the switching drive shaft, it can be handled by an inexpensive sensor such as a simple on / off switch, and the cost can be suppressed.

In a preferred embodiment of the invention
The detected portion is formed of a recess provided on the side surface of the switching drive shaft and outer portions on both sides of the opening of the recess.
The sensor identifies and detects different states of the recess and the outer portion of the switching drive shaft.

According to this configuration, the detected portion is formed by the recess provided on the side surface of the switching drive shaft and the outer portions on both sides of the opening of the recess, and the sensor has two different states, the recess and the outer portion of the switching drive shaft. The sensor can accurately determine the valve operating characteristics from the moving state of the switching drive shaft even with a simple sensor such as an on / off switch that detects two states of the detected portion.

In a preferred embodiment of the invention
The switching drive shaft is provided with two detected portions.
The two sensors detect the state of each of the two detected parts,
Prior to the movement of the switching drive shaft, one of the sensors detects an outer portion of one of the detected portions, and the other sensor detects a recess of the other detected portion.
After the switching drive shaft is moved, one of the sensors detects a recess of one of the detected portions, and the other sensor detects an outer portion of the other detected portion.

According to this configuration, two sensors detect the respective states of the two detected parts, one sensor detects the outer part of one detected part and the other sensor detects the outer part of one detected part before the switching drive shaft moves. Detects the recess of the other detected portion, and after the switching drive shaft moves, one sensor detects the recess of one detected portion, and the other sensor detects the outer portion of the other detected portion.

That is, since the two sensors have different detection results before and after the switching drive shaft is moved, it can be determined that the two sensors are moving when the same detection result or only one of them does not change.
Therefore, using the minimum required two sensors, it is possible to determine the state of the switching drive shaft in the middle of movement and accurately determine the change in the detection results of the plurality of sensors after the movement, and the movement of the switching drive shaft. The moving state of the switching drive shaft can be determined to the extent that it can be determined whether or not is in the completed state, and the valve operating characteristics can be accurately determined from the moving state of the switching drive shaft.
If the two sensors have the same detection result after the switching drive shaft is moved, it can be determined that the variable valve gear is operating abnormally or the sensor is abnormal.

In a preferred embodiment of the invention
The valve operating characteristic determination means is
When the switching drive shaft moves normally, a predetermined time equal to or longer than the time from the start of the movement to the completion of the movement is set in advance.
Assuming that the switching drive shaft has moved after the predetermined time has elapsed from the time of the cam switching instruction of the switching drive shaft, the detection result of the sensor is read, and the detection of the sensor before and after the movement of the switching drive shaft is performed. Whether or not there is a change in the result is determined, and the valve operating characteristic is determined from the moving state of the switching drive shaft.

According to this configuration, when the switching drive shaft moves normally, a predetermined time equal to or longer than the time from the start of the movement to the completion of the movement is set in advance, and from the time when the cam switching instruction of the switching drive shaft is instructed. Assuming that the switching drive shaft has been moved after the elapse of a predetermined time, the detection result of the sensor can be read after the elapse of the predetermined time, and the detection result of the sensor after the movement of the switching drive shaft can be easily obtained.

In a preferred embodiment of the invention
The predetermined time is set as about twice the time required from the time when the cam switching instruction is given until the valve operating characteristic is switched.

According to this configuration, the switching of the valve operating characteristics is not completed by setting the time as about twice the time from the start of movement of the switching drive shaft (71,81) to the switching of the valve operating characteristics ( The output can be adjusted at an early timing even if there is a problem with the variable valve mechanism.

In a preferred embodiment of the invention
The variable valve gear is provided in an internal combustion engine mounted on a vehicle.

According to this configuration, since the variable valve gear is provided in the internal combustion engine mounted on the vehicle, the valve operating characteristic determining means accurately determines the valve operating characteristic from the moving state of the switching drive shaft, and the valve operating characteristic is determined. When it is determined that the switching is not completed, it is possible to reduce the unnecessary load on the internal combustion engine by taking measures such as suppressing the output of the internal combustion engine to reduce the vehicle speed and running the vehicle.

In the present invention, the valve operating characteristic determining means determines whether or not there is a change in the detection result of each of the plurality of sensors before and after the movement of the switching drive shaft, and the valve is based on the moving state of the switching drive shaft. Since the operating characteristics are determined, whether or not the shift of the cam carrier is completed by determining the change in the detection results of the plurality of sensors after the movement in consideration of the state during the movement of the switching drive shaft by the plurality of sensors. The moving state of the switching drive shaft can be determined to the extent that it can be determined, and the valve operating characteristics can be accurately determined from the moving state of the switching drive shaft.
Since the sensor detects whether or not there is a change in the detection result before and after the movement of the switching drive shaft, it can be handled by an inexpensive sensor such as a simple on / off switch, and the cost can be suppressed.

It is an overall side view of the motorcycle which mounts the internal combustion engine equipped with the variable valve gear which concerns on one Embodiment of this invention. It is a left side view of the internal combustion engine. It is a top view of the internal combustion engine. It is the left side view which showed the outline of the cylinder head of the internal combustion engine by a two-dot chain line, and showed the main part of the internal valve gear through. It is the top view which looked at the upper cylinder head with the cylinder head cover removed. It is a perspective view which shows only the main main part by omitting a part of the intake side cam switching mechanism and the exhaust side cam switching mechanism. It is a perspective view of the intake side cam carrier. It is a perspective view which attached the 1st switching pin and the 2nd switching pin to the intake side switching drive shaft. It is a perspective view which removed the cylinder head cover of the main body of the engine and omitted the upper cylinder head. It is explanatory drawing which shows one operation state of the intake side cam switching mechanism and the limit switch. It is explanatory drawing which shows another operation state of the intake side cam switching mechanism and the limit switch. It is explanatory drawing which shows the other operating state of the intake side cam switching mechanism and a limit switch. It is an image diagram of the timing chart which shows the on / off state of the left and right intake side limit switches with the movement of the intake side switching drive shaft. It is a table which showed the detection result of the limit switch with the movement of a switching drive shaft, and the position of a switching drive shaft and a cam carrier.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS. 1 to 14.
FIG. 1 is a side view of a motorcycle 500, which is a saddle-type vehicle equipped with an internal combustion engine including a variable valve gear according to an embodiment to which the present invention is applied.
In the present specification and claims, the front-rear, left-right directions shall be in accordance with the usual standard that the straight-ahead direction of the motorcycle 500 according to the present embodiment is the front, and in the drawings, FR refers to the front and RR. Is for the rear, LH is for the left, and RH is for the right.

The body frame of the motorcycle 500 has a pair of left and right main frames 503 extending diagonally downward from the head pipe 502 that supports the front fork 505 that pivotally supports the front wheels 506.
The engine hanger portion 503a hangs downward from the front portion of the main frame 503, and the rear portion of the main frame 503 is bent so that the pivot frame portion 503b extends downward.
The seat rail 504 is connected to the rear side of the center of the main frame 503 and extends rearward.

A swing arm 508 whose front end is pivotally supported by a pivot shaft 507 extends rearward to the pivot frame portion 503b, and a rear wheel 509 is pivotally supported by the rear end of the swing arm 508.
A link mechanism 510 is provided between the swing arm 508 and the pivot frame portion 503b, and a rear cushion 511 is interposed between a part of the link mechanism 510 and the seat rail 504.

A power unit Pu is suspended between the engine hanger portion 503a of the main frame 503 and the pivot frame portion 503b on the vehicle body frame, and the traveling drive is fitted to the output shaft which is the counter shaft of the transmission M of the power unit Pu. A traveling drive chain 514 is laid between the sprocket 512 and the traveling driven sprocket 513 fitted to the rear axle of the rear wheel 509.

An air cleaner 522 is installed in the first half of the main frame 503, and a fuel tank 516 is installed in the second half. A main seat 517 and a pillion seat 518 are supported by a seat rail 504 behind the fuel tank 516.

The internal combustion engine E, which occupies the first half of the power unit Pu, is an in-line 4-cylinder water-cooled 4-stroke internal combustion engine in which the crank is placed horizontally, and is mounted on the vehicle body frame in a posture in which the cylinders are appropriately tilted forward.
The crankshaft 10 of the internal combustion engine E is pivotally supported by the crankcase 1 in the width direction (left-right direction) of the vehicle body, and the crankcase 1 integrally includes a transmission M behind the crankshaft 10.

With reference to FIG. 2, the internal combustion engine E has a cylinder block 2 in which four cylinders are arranged in series on the crankcase 1, and a cylinder head 3 connected to the upper portion of the cylinder block 2 via a gasket. And an engine body including a cylinder head cover 4 that covers the upper part of the cylinder head 3.

The cylinder axis Lc, which is the central axis of the cylinder bore of the cylinder block 2, is tilted forward, and the cylinder block 2, the cylinder head 3, and the cylinder head cover 4 stacked on the crankcase 1 are slightly tilted forward from the crankcase 1. It extends upward in a posture.
Further, an oil pan 5 is provided below the crankcase 1 so as to bulge downward.

The crankcase 1 is vertically split, and the crankshaft 10 is pivotally supported by being sandwiched between the split surfaces of the upper crankcase 1U and the lower crankcase 1L.
The crankcase 1 has a transmission M built in behind the crankshaft 10, and the main shaft 11 and the counter shaft 12 constituting the transmission M are directed in the vehicle body width direction in parallel with the crankshaft 10. It is pivotally supported by 1 (see FIG. 2).

In the transmission chamber of the crankcase 1, the main shaft 11 and the counter shaft 12 of the transmission M are arranged in parallel with the crankshaft 10 in the left-right horizontal direction (see FIG. 3), and the counter shaft 12 Penetrates the crankcase 1 to the left and projects outward to form an output shaft.

On the rear side surface of the cylinder head 3, an intake pipe extending for each cylinder is connected to the air cleaner 522 via a throttle body 521 (see FIG. 1).
Further, on the front side surface of the cylinder head 3, an exhaust pipe 525 extends for each cylinder, and each exhaust pipe 525 extends downward and bends rearward, and the right side of the oil pan 5 extends rearward.

The internal combustion engine E is equipped with a variable valve device 40 having a DOHC structure in the cylinder head 3 in a 4-valve system.
The cylinder head 3 of the internal combustion engine E is divided into upper and lower parts in the cylinder axis direction (the axis direction of the cylinder axis Lc), and the lower cylinder head 3L overlaid on the cylinder block 2 and the lower cylinder head 3L are stacked on the cylinder block 2. It consists of an upper cylinder head 3U stacked on top of it (see FIGS. 2 and 4).

With reference to FIG. 4, in the lower cylinder head 3L, for each cylinder, two intake ports 31i are curved rearward and extend diagonally upward from the combustion chamber 30, and two exhaust ports 31e are curved forward. It is extended.
In the lower cylinder head 3L, an intake valve 41 and an exhaust valve 51 that open and close the intake opening of the intake port 31i to the combustion chamber 30 and the exhaust opening of the exhaust port 31e to the combustion chamber 30, respectively, are used to rotate the crank shaft 10. It is supported so that it can slide back and forth in synchronization.

The lower cylinder head 3L is integrally fastened to the upper crankcase 1U together with the cylinder block 2 by a stud bolt 7 (see FIGS. 4 and 5).
The upper cylinder head 3U stacked on the lower cylinder head 3L has a long front side wall 3Fr and a rear side wall 3Rr on the left and right, and a short left side wall 3Lh and a right side wall on the front and back, referring to FIG. 5 which is a top view. A rectangular frame wall is formed by 3Rh.

The inside of the rectangular frame of the upper cylinder head 3U is divided into a narrow cam chain chamber 3c on the right side and a valve operating chamber 3d on the left side by a bearing wall 3vr formed in parallel along the right side wall 3Rh, and the valve operating chamber 3d is further divided. It is divided into five chambers by four bearing walls 3v parallel to the left and right side walls 3Lh and 3Rh.
Each bearing wall 3v is located above the center of the combustion chamber 30 of each cylinder, and a plug fitting insertion tube portion 3vp for inserting a spark plug is formed in the center in the front-rear direction.

The variable valve gear 40 is provided in the valve chamber 3d formed by the cylinder head 3 and the cylinder head cover 4.
With reference to FIGS. 4 and 5, the pair of left and right intake valves 41, 41 provided in each of the four cylinders in series are arranged in series in the left-right direction, and the four pairs of intake valves 41, 41 are arranged in series. One intake side camshaft 42 is arranged so as to face in the left-right direction on the upper side, and is fitted into the bearing wall 3v of the upper cylinder head 3U and the bearing 3vv forming the semi-arc surface of 3vr and sandwiched between the camshaft holders 33. It is rotatably supported by the shaft.

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

With reference to FIG. 5, the intake side camshaft 42 has a bearing portion 42a axially supported by the bearing wall 3vr near the right end, and the bearing wall 3vr is sandwiched by the flanges on both sides of the bearing portion 42a in the axial direction. On the left side of the bearing portion 42a, the spline shaft portion 42b having spline outer teeth formed on the outer peripheral surface penetrates the four bearing walls 3v of the valve chamber 3d and extends long.
The intake side driven gear 47 is fitted to the flange at the right end protruding into the cam chain chamber 3c of the intake side camshaft 42.

Similarly, the exhaust side camshaft 52 has a bearing portion 52a axially supported by the bearing wall 3vr near the right end, and is positioned axially with the bearing wall 3vr sandwiched between the flanges on both sides of the bearing portion 52a. On the left side of the bearing portion 52a, the spline shaft portion 52b penetrates the four bearing walls 3v of the valve chamber 3d and extends long on the outer peripheral surface.
The exhaust side driven gear 57 is fitted to the flange at the right end protruding into the cam chain chamber 3c of the exhaust side camshaft 52.

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

FIG. 6 is a perspective view showing only the main main parts by omitting a part of the intake side cam switching mechanism and the exhaust side cam switching mechanism, and FIG. 7 is a perspective view of the intake side cam carrier 43.
With reference to FIG. 7, each intake side cam carrier 43 has a pair of high-speed side cam lobs 43A having different cam profiles and a low-speed side cam lob 43B having a small lift amount adjacent to each other on the left and right in the axial direction. , One set is formed on each side of the bearing cylindrical portion 43C having a predetermined width in the axial direction.
The adjacent high-speed cam lob 43A and low-speed cam lob 43B have the same outer diameter of the base circle of each cam profile, and the base circles are in the same circumferential position.

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

The lead groove 44 of the lead groove cylindrical portion 43D is formed with a stationary lead groove 44c that goes around in the circumferential direction at a fixed position in the axial direction, and is branched to the left and right from the stationary lead groove 44c at a position separated from the stationary lead groove 44c by a predetermined distance to the left and right in the axial direction. The left shift lead groove 44l and the right shift lead groove 44r are spirally formed up to.

On the other hand, the exhaust side cam carrier 53, which is spline-fitted to the spline shaft portion 52b of the exhaust side camshaft 52, also has the same shape as the intake side cam carrier 43, and has the same shape as the high speed side cam lob 53A, the low speed side cam lob 53B, and the bearing cylinder. A portion 53C and a lead groove cylindrical portion 53D are formed, and a steady lead groove 54c, a right shift lead groove 54r, and a left shift lead groove 54l are formed in the lead groove cylindrical portion 53D (see FIGS. 5 and 6).

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

As described above, the intake side camshaft 42 (and the intake side cam carrier 43) and the exhaust side cam shaft 52 (and the exhaust side cam carrier 53) are attached to the bearing wall 3vr and the four bearing walls 3v of the upper cylinder head 3U. When supported, the intake side camshaft 42 (and intake side camcarrier 43) and the exhaust side camshaft 52 are respectively superposed on the bearing wall 3vr and the four bearing walls 3v by the camshaft holder 33 (see FIG. 4). (And the exhaust side cam carrier 53) is sandwiched and rotatably bearing.

That is, the four intake side cam carriers 43 are pivotally supported so as to be slidable in the axial direction while rotating together with the intake side cam shaft 42, and the four exhaust side cam carriers 53 are also shafts while rotating together with the exhaust side cam shaft 52. It is pivotally supported so that it can slide in the direction.

The intake side driven gear 47 attached to the right end of the intake side camshaft 42 and the exhaust side driven gear 57 attached to the right end of the exhaust side camshaft 52 have the same diameter and are lined up in the rear and front in the cam chain chamber 3c. As shown in FIG. 4, a large-diameter idle gear 61 that meshes with both the intake side driven gear 47 and the exhaust side driven gear 57 is rotatably supported downward between the two. Has been done.
The power of the lower crankshaft 10 is transmitted to the idle gear 61 via the cam chain 66 and the like.

With reference to FIG. 6, the intake side switching drive shaft 71 of the intake side cam switching mechanism 70 is arranged in parallel with the intake side camshaft 42 and diagonally downward in front of the intake side camshaft 42, and the exhaust side camshaft 52. The exhaust side switching drive shaft 81 of the exhaust side cam switching mechanism 80 is arranged in parallel with the exhaust side cam shaft 52 diagonally downward in front of the above.

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

Similarly, in the upper cylinder head 3U, a cylindrical portion 3B oriented in the left-right direction toward the valve chamber 3d is formed in a straight line on the inner surface of the front side wall 3Fr through the bearing wall 3vr and the four bearing walls 3v. (See FIG. 5).
The intake side switching drive shaft 71 is slidably fitted in the shaft hole of the tubular portion 3A, and the exhaust side switching drive shaft 81 is slidably fitted in the shaft hole of the tubular portion 3B. Is done.

Two locations corresponding to the left and right intake valves 41 and 41 are missing at both sides of the cylindrical portion 3A with the bearing wall 3v in between, and the intake side switching drive shaft 71 is exposed. The intake rocker arms 72, 72 are oscillatingly supported on the exposed portion of 71 (see FIG. 5).
That is, the intake side switching drive shaft 71 also serves as a rocker arm shaft.

With reference to FIGS. 4 and 6, the tip of the intake rocker arm 72 abuts on the upper end of the intake valve 41, and the curved upper end surface of the intake rocker arm 72 is moved at higher speed by the axial movement of the intake side cam carrier 43. Either the side cam lob 43A or the low speed side cam lob 43B is in sliding contact.
Therefore, when the intake side cam carrier 43 rotates, either the high speed side cam lob 43A or the low speed side cam lob 43B swings the intake rocker arm 72 according to the profile and presses the intake valve 41 to press the intake valve 41 and the intake valve port of the combustion chamber 30. open.

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

With reference to FIGS. 4 and 6, the tip of the exhaust rocker arm 82 abuts on the upper end of the exhaust valve 51, and the curved upper end surface of the exhaust rocker arm 82 is moved to the exhaust side cam carrier 53 to move the exhaust side cam carrier 53 to the high speed side cam lob 53A. Alternatively, one of the low-speed cam lobs 53B is in sliding contact.
Therefore, when the exhaust side cam carrier 53 rotates, either the high speed side cam lob 53A or the low speed side cam lob 53B swings the exhaust rocker arm 82 according to the profile and presses the exhaust valve 51 to press the exhaust valve 51 to open the exhaust valve port of the combustion chamber 30. open.

With reference to FIG. 5, two cylindrical boss portions 3As and 3As adjacent to the left and right are directed toward the lead groove cylindrical portion 43D at a position corresponding to the lead groove cylindrical portion 43D of the intake side cam carrier 43 in the tubular portion 3A. It is formed so as to protrude.
The hole inside the cylindrical boss portion 3As has a bottom.
Coil springs 75 and 75 are inserted into the inner holes of the left and right cylindrical boss portions 3As and 3As, respectively, and the first switching pin 73 and the second switching pin 74 are slidably inserted.

With reference to FIG. 8, in the first switching pin 73, the tip side cylinder portion 73a and the base end cylinder portion 73b having the same diameter are connected by a small diameter connecting cylinder portion 73c, and the tip side cylinder portion 73a is connected to the tip. The engaging end 73d protrudes.
When the first switching pin 73 advances, the engaging end portion 73d at the tip thereof engages with the lead groove 44.

The end surface of the base end cylindrical portion 73b of the first switching pin 73 on the connecting cylindrical portion 73c side is a spherical end surface 73bf forming a spherical surface.
The second switching pin 74 also has the same shape as the first switching pin 73, and the intermediate connecting rod portion 74c connects the tip cylindrical portion 74a and the base end cylindrical portion 74b in a straight line.

On the other hand, as shown in FIG. 8, the intake side switching drive shaft 71 has a long hole 71h formed in the axial direction penetrating the center of the shaft, and the width of the long hole 71h is the width of the first switching pin 73. It is slightly larger than the diameter of the connecting cylindrical portion 73c, but smaller than the diameter of the base end cylindrical portion 73b.
On one open end surface of the elongated hole 71h of the intake side switching drive shaft 71, a cam surface in which a concave curved surface 71Cv formed by being recessed in a predetermined shape between two flat surfaces 71Cp and 71Cp on the left and right is continuously formed. 71C is configured.

As shown in FIG. 8, a circular hole 71d penetrating the center of the shaft is formed at the right end of the elongated hole 71h.
The inner diameter of the circular hole 71d is slightly larger than the outer diameter of the base end cylindrical portion 73b of the first switching pin 73.
When assembling the first switching pin 73 to the intake side switching drive shaft 71, the base end cylindrical portion 73b of the first switching pin 73 is penetrated through the circular hole 71h, and the connecting cylindrical portion 73c is inserted into the elongated hole 71h. By sliding the side switching drive shaft 71, the first switching pin 73 can be assembled at a position corresponding to the cam surface 71C of the intake side switching drive shaft 71.
The second switching pin 74 can be assembled in the same manner.

In the first switching pin 73, the connecting cylindrical portion 73c penetrates the elongated hole 71h of the intake side switching drive shaft 71 and is urged by the coil spring 75, and the spherical end surface 73bf of the base end cylindrical portion 73b is the intake side switching drive shaft 71. It is assembled in a state of being pressed against the cam surface 71C, which is the open end surface of the elongated hole 71h.
Therefore, when the intake side switching drive shaft 71 moves in the axial direction, the spherical end surface 73bf of the base end cylindrical portion 73b of the first switching pin 73 that is in the fixed position in the axial direction and slides in the direction orthogonal to the axial direction becomes the cam surface. A linear cam mechanism Ca that comes into contact with the 71C and is guided by the shape of the cam surface 71C so that the first switching pin 73 advances and retreats in the direction perpendicular to the axial direction is configured.

As shown in FIG. 8, the first switching pin 73 and the second switching pin 74 are arranged side by side in parallel with each other through the common elongated hole 71h of the intake side switching drive shaft 71.
FIG. 8 shows a state in which the center of the concave curved surface 71Cv of the cam surface 71C of the intake side switching drive shaft 71 is at the position of the first switching pin 73, and the first switching pin 73 has a spherical end surface on the concave curved surface 71Cv. The second switching pin 74 is in a position where the cam surface 71C is in contact with the flat surface 71Cp and is in a recessed position.

When the intake side switching drive shaft 71 moves to the left from this state, the spherical end surface 73bf regresses from the center of the concave curved surface 71Cv to the right flat surface 71Cp while climbing the right inclined surface of the concave curved surface 71Cv. The second switching pin 74 comes into contact with the center of the concave curved surface 71Cv as the spherical end surface 74bf advances from the flat surface 71Cp down the left inclined surface of the concave curved surface 71Cv.
In this way, the first switching pin 73 and the second switching pin 74 can be alternately moved forward and backward by moving the intake side switching drive shaft 71 in the axial direction.

The first switching pin 83 and the second switching pin 84 are slidable in the cylindrical portion 3B into which the exhaust side switching drive shaft 81 is slidably inserted in the axial direction, as in the case of the tubular portion 3A. Two cylindrical boss portions 3Bs and 3Bs to be fitted are formed adjacent to each other on the left and right, and the first switching pin 83 and the second switching pin 84 penetrate the common elongated hole 81h of the exhaust side switching drive shaft 81. They are arranged side by side in parallel with each other (see FIGS. 5 and 6).

As the exhaust side switching drive shaft 81 moves in the axial direction, the first switching pin 83 and the second switching pin 84 move in the axial direction due to the cam surface 81C of the elongated hole 81h (cam surface having the same shape as the cam surface 71C, see FIG. 7). A linear cam mechanism Cb that advances and retreats alternately in the direction perpendicular to the above is configured.

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

In the intake side hydraulic actuator 77, the intake side actuator drive body 79 having a bottomed cylindrical shape reciprocates in the axial direction (left-right direction) of the intake side switching drive shaft 71 in the circular hole-shaped housing inner chamber of the intake side actuator housing 78. It is slidably fitted, and the left end of the intake side switching drive shaft 71 is fitted to the intake side actuator drive body 79 and moves integrally.

Similarly, in the exhaust side hydraulic actuator 87, the exhaust side actuator drive body 89 having a bottomed cylindrical shape is fitted in the circular hole-shaped housing inner chamber of the exhaust side actuator housing 88 so as to be reciprocally slidable in the left-right direction. The left end of the exhaust side switching drive shaft 81 is fitted to the exhaust side actuator drive body 89 and moves integrally.

A linear solenoid valve 91 is attached to the left end mating surface on the front surface of the front side wall 3Fr of the upper cylinder head 3U.
The linear solenoid valve 91 is provided with a sleeve 93 as an extension of the solenoid solenoid 92 in which the plunger moves in the solenoid coil.

The linear solenoid valve 91 supplies pressure oil from the sleeve 93 to the intake side hydraulic actuator 77 and the exhaust side hydraulic actuator 87, and the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 are moved in the axial direction.

The intake side switching drive shaft 71 of the variable valve gear 40 is provided with two detected portions 71a and 71b apart from each other in the axial direction (see FIGS. 9 and 10).
As shown in FIG. 10, the detected portion 71a on the left side (which is the right side in FIG. 10) has an axially long recess 71a0 formed so as to cut the side surface of the intake side switching drive shaft 71 and the recess 71a0. It is formed by the outer outer portions 71a1 and 71a1 through the inclined portions on both sides of the above.
Similarly, the detected portion 71b on the right side also has a recess 71b0 formed so as to cut the side surface of the intake side switching drive shaft 71, and the outer outer portions 71b1 and 71b1 via the inclined portions on both sides of the recess 71b0. It is formed.

The intake side limit switches Sia and Sib that detect the states of the two left and right detected portions 71a and 71b at predetermined positions on the left and right are attached to the upper cylinder head 3U.
The intake side limit switches Sia and Sib are in the off state when the detection pins Sia and Sib are urged by a spring and protrude from the tip, and the detection pins Sia and Sib are in the off state and are protruding when no external force is applied. When the Siap and Sibp are pushed by a predetermined distance against the spring, the switch is turned on.

Similar to the intake side switching drive shaft 71, the exhaust side switching drive shaft 81 of the variable valve gear 40 is also provided with two detected parts 81a and 81b separated from each other in the axial direction, and the two left and right detected parts 81a are provided. The exhaust side limit switches Sea and Seb, which detect the states of 81 and 81b at predetermined positions on the left and right, are attached to the upper cylinder head 3U (see FIG. 9).

The intake side switching drive shaft 71 moves in the left-right axial direction between the right side predetermined position and the left side predetermined position, and the state of the intake side switching drive shaft 71 shown in FIG. 10 is in the right side predetermined position and the intake air on the left side. In the side limit switch Sia, the detection pin Siap protrudes into the recess 71a0 of the left side of the detected portion 71a without touching the bottom surface of the recess 71a0 and is in an off state. The detection pin Sibp is pushed by a predetermined distance to the outer portion 71b1 on the left side of the recess 71b0 of the above, and is in the ON state.

At this time, the base end cylindrical portion 73b of the first switching pin 73 advances in contact with the concave curved surface 71Cv of the cam surface 71C of the intake side switching drive shaft 71, and the second switching pin 74 advances with its base end cylindrical portion. 74b abuts on the flat surface 71Cp of the cam surface 71C of the intake side switching drive shaft 71 and regresses.
The advanced first switching pin 73 engages with the steady lead groove 44c of the lead groove 44 of the intake side cam carrier 43 and maintains the intake side cam carrier 43 in a state of being shifted to the right (high speed side position). The rocker arm 72 is in sliding contact with the high-speed side cam lob 43A, and the intake valve 41 operates according to the valve operating characteristics set in the cam profile of the high-speed side cam lob 43A.

The left intake side limit switch Sia has a detection pin Sia projecting toward the left end portion of the left side portion 71a to be detected, which is long in the axial direction and is close to the left outer portion 71a1.
Further, the intake side limit switch Sib on the right side is in contact with the outer portion 71b1 on the left side near the recess 71b0 of the detected portion 71b on the right side, and the detection pin Sibp is pressed.

The variable valve operating device 40 includes a valve operating characteristic determining means 100 (see FIGS. 10, 11, and 12), and the valve operating characteristic determining means 100 is equipped with the above two intake side limit switches Sia and Sib. A detection signal (on / off signal) is input, and the valve operating characteristic determination means 100 determines the valve operating characteristic from the moving state of the intake side switching drive shaft 71.

When the intake side switching drive shaft 71 shown in FIG. 10 is in a predetermined position on the right side, an off signal is output from the intake side limit switch Sia on the left side and an on signal is output from the intake side limit switch Sib on the right side. The determination means 100 inputs these two detection signals, and since the intake side limit switch Sia on the left side is off and the intake side limit switch Sib on the right side is on, the intake side switching drive shaft 71 is in the right predetermined position. It is determined that the intake valve 41 is in a state of operating according to the valve operating characteristics of the high-speed side cam lob 43A.

FIG. 11 shows a state in which the intake side switching drive shaft 71 is moving to the left by driving the intake side hydraulic actuator 77 from the state shown in FIG.
The left intake side limit switch Sia has its detection pin Sia projecting into the axially long recess 71a0 of the detected portion 71a on the left side of the intake side switching drive shaft 71 and remains in the off state. The intake side limit switch Sib is turned off when its detection pin Sibp projects toward the recess 71b0 of the detected portion 71b on the right side.
That is, during the movement of the intake side switching drive shaft 71, both the left and right intake side limit switches Sia and Sib are turned off.

At this time, in the first switching pin 73, the base end cylindrical portion 73b abuts on the inclined portion of the concave curved surface 71Cv of the cam surface 71C and slightly recedes from the steady lead groove 44c of the intake side cam carrier 43. The second switching pin 74 is slightly advanced because its base end cylindrical portion 74b abuts on the inclined portion of the concave curved surface 71Cv of the cam surface 71C, but the second switching pin 74 is slightly advanced, but the left shift lead groove of the intake side cam carrier 43. Since it is not yet engaged with 44l, the intake side cam carrier 43 has not moved in the axial direction.

FIG. 12 shows a state when the intake side switching drive shaft 71 further moves to the left from the state shown in FIG. 11 and reaches a predetermined position on the left side.
When the intake side switching drive shaft 71 shown in FIG. 12 is in the left side predetermined position, the left intake side limit switch Sia has a detection pin Siap at a predetermined distance to the outer portion 71a1 on the right side of the recess 71a0 of the detected portion 71a on the left side. The right intake side limit switch Sib is pushed and turned on, and the detection pin Sibp projects into the recess 71b0 of the detected portion 71b on the left side and is in the off state.

At this time, the base end cylindrical portion 73b of the first switching pin 73 regresses in contact with the flat surface 71Cp of the cam surface 71C of the intake side switching drive shaft 71, and the second switching pin 74 retreats. 74b is advancing in contact with the concave curved surface 71Cv of the cam surface 71C.

The advanced second switching pin 74 engages with the left shift lead groove 44l of the lead groove 44 of the intake side cam carrier 43, moves the intake side cam carrier 43 to the left, and moves to the steady lead groove 44c. In addition, the intake side cam carrier 43 is maintained in a state of being shifted to the left side (low speed side position).
Therefore, when the intake side cam carrier 43 shifts to the left, the intake rocker arm 72 moves from the high speed side cam lob 43A to the low speed side cam lob 43B and slides into contact with the valve operating characteristic set in the cam profile of the low speed side cam lob 43B. The intake valve 41 operates accordingly.

When the intake side switching drive shaft 71 shown in FIG. 12 is in the left predetermined position, an on signal is output from the left intake side limit switch Sia and an off signal is output from the right intake side limit switch Sib, and the valve operating characteristics. The determination means 100 inputs these two detection signals, and since the left intake side limit switch Sia is on and the right intake side limit switch Sib is off, the intake side switching drive shaft 71 is in the left predetermined position. It is determined that the intake valve 41 is in a state of operating according to the valve operating characteristics of the low-speed side cam lob 43B.

FIG. 13 shows an image of a timing chart showing an on / off state of the left intake side limit switch Sia and the right intake side limit switch Sib accompanying the movement of the intake side switching drive shaft 71.
FIG. 13 shows the moving state of the intake side switching drive shaft 71 and the moving state of the intake side cam carrier 43 together.

In the timing chart of FIG. 13, the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81, the intake side cam carrier 43, and the exhaust side cam carrier 53 of the variable valve device 40 operate normally, and the intake side limit is shown. This is when the switches Sia and Sib and the exhaust side limit switches Sea and Seb operate normally.
When the intake side limit switches Sia and Sib and the exhaust side limit switches Sia and Seb are switched on and off, there are indefinite sections α and β whose on / off is not determined by chattering at the inclined portions of the detected portions 71a and 71b.

The intake side switching drive shaft 71 starts moving at the movement start time Ts slightly delayed from the cam switching instruction time point To when the cam switching instruction is issued.
Before the start of movement of the intake side switching drive shaft 71 of To at the time of the cam switching instruction, the intake side limit switch Sia on the left side is in the off state and the intake side limit switch Sib on the right side is in the on state in the state shown in FIG. ..
At the time of the cam switching instruction To, the intake side switching drive shaft 71 is in the right side predetermined position, the intake side cam carrier 43 is in the right high speed side position, and the intake valve 41 is due to the valve operating characteristics by the high speed side cam lob 43A. Operate.

When the intake side switching drive shaft 71 starts moving, the intake side limit switch Sib on the right side is first turned off through the inclined portion of the detected portion 71b.
After that, due to the movement of the intake side switching drive shaft 71, the first switching pin 73 that abuts on the cam surface 71C retracts, the second switching pin 74 advances, and engages with the left shift lead groove 44l of the intake side cam carrier 43. Then, the intake side cam carrier 43 shifts to the left.
At the start of the shift of the intake side cam carrier 43, there is an indefinite section γ whose start time is not determined slightly before and after due to the start delay of the solenoid solenoid 92 and the degree of operation delay of the linear solenoid valve 91.

After that, while the intake side switching drive shaft 71 is moving and the left and right intake side limit switches Sia and Sib are both off, the shift of the intake side cam carrier 43 is completed, and the intake side cam carrier 43 is on the left side. The intake valve 41 operates according to the valve operating characteristics of the low-speed side cam lob 43B.
After that, before the movement of the intake side switching drive shaft 71 is completed, the intake side limit switch Sia on the left side is turned on from the off through the inclined portion of the detected portion 71a.
At the subsequent movement stop time Te, the intake side switching drive shaft 71 stops at a predetermined position on the left side.

The change in the on / off state of the two intake side limit switches Sia and Sib due to the movement of the intake side switching drive shaft 71 has been described above. The same applies to the change in the on / off state of the Seb.
The detection signals (on / off signals) of these two exhaust side limit switches Sea and Seb are also input to the valve operating characteristic determining means 100, and the valve operating characteristic is changed from the moving state of the exhaust side switching drive shaft 81 by the valve operating characteristic determining means 100. Judged.

The valve operating characteristic determining means 100 determines whether or not there is a change in the detection results of the two intake side limit switches Sia and Sib before and after the movement of the intake side switching drive shaft 71, and determines whether or not there is a change in the intake side switching drive. The valve operating characteristics are determined from the moving state of the shaft 71, and similarly, whether or not there is a change in the detection results of the two exhaust side limit switches Sea and Seb before and after the movement of the exhaust side switching drive shaft 81 is performed. The valve operating characteristics are determined from the moving state of the exhaust side switching drive shaft 81.

The valve operating characteristic determining means 100 turns on and off the two intake side limit switches Sia and Sib before the movement of the intake side switching drive shaft 71 and the two exhaust side limit switches Sea and Seb before the movement of the exhaust side switching drive shaft 81. Although the state is memorized, the detection results of the intake side limit switches Sia and Sib and the exhaust side limit switches Sea and Seb before the movement of the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 at the time of the cam switching instruction To. May be read.

When the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 operate normally, a predetermined time Dt equal to or longer than the time from the start of movement to the completion of movement is preset in the valve operating characteristic determination means 100. I will do it.

With reference to FIG. 13, the required time dt from the cam switching instruction time To to the time when the valve operating characteristic is switched can be measured in advance, and twice the required time dt can be set as the predetermined time Dt. ..
If a predetermined time Dt has elapsed from the cam switching instruction time To, the output can be adjusted at an early timing even if the switching of the valve operating characteristics is incomplete (such as a malfunction of the variable valve mechanism).

With reference to FIG. 13, the valve operating characteristic determining means 100 assumes that the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 have been moved after a predetermined time Dt has elapsed from the cam switching instruction time point To, and the intake side. By reading the detection results of the intake side limit switches Sia and Sib and the exhaust side limit switches Sea and Seb after the movement of the switching drive shaft 71 and the exhaust side switching drive shaft 81, the detection result of the limit switch after the movement of the switching drive shaft Can be easily obtained.

The table below shows the detection results of the intake side limit switches Sia and Sib and the exhaust side limit switches Sia and Seb before, during, and after the movement of the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81. FIG. 14 is a diagram.
In FIG. 14, the positions of the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 and the positions of the intake side cam carrier 43 and the exhaust side cam carrier 53 are also shown in the table.
The table of FIG. 14 shows the case where the variable valve gear 40 operates normally.

As is clear from the table of FIG. 14, when the variable valve gear 40 operates normally, before and after the movement of the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81, the intake side limit switch Sia , Sib and the detection results of the exhaust side limit switches Sea and Seb are all changing.

Therefore, if the detection results of the intake side limit switches Sia and Sib and the exhaust side limit switches Sia and Seb are all changed, the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81 are in the completed movement state. There is no mistake even if it is judged.

If at least one of the intake side limit switches Sia and Sib does not change in the detection result before and after the movement of the intake side switching drive shaft 71, the intake side switching drive shaft 71 has not completed the movement and is in the process of moving. It can be judged that it may have stopped at.
Similarly, if at least one of the exhaust side limit switches Sea and Seb does not change in the detection result before and after the movement of the exhaust side switching drive shaft 81, the movement of the exhaust side switching drive shaft 81 is completed. It can be determined that there is a possibility that the vehicle has stopped in the middle of moving.

In this way, in addition to the abnormality in which the switching drive shaft is stopped in the middle of movement for some reason, an abnormality in the limit switch itself is also conceivable. Therefore, it is possible to take some measures to avoid obstacles due to the abnormality as much as possible.

Further, when considering the example shown in the timing chart of FIG. 13 as a reference, when all the detection results of the two intake side limit switches Sia and Sib change (the left intake side limit switch Sia changes from off to on). At the time of change), the intake side cam carrier 43 has already completed the shift to the left and is in the low speed side position.

Therefore, when all the detection results of the intake side limit switches Sia and Sib change before and after the movement of the intake side switching drive shaft 71, the shift of the intake side cam carrier 43 is completed and the valve operating characteristics are switched. It can be judged with high accuracy.

This variable valve gear 40 uses the minimum necessary two inexpensive sensors called limit switches Sia and Sib (Sea, Seb) to change the detection result before and after the movement of the switching drive shaft 71 (81). Therefore, it is not necessary to discriminate the detection signal based on the reference value, and it is possible to judge with high accuracy that the valve operating characteristics have been switched, which is low cost.

As described above, the valve operating characteristic determining means 100 determines the change in the detection results of the two intake side limit switches Sia and Sib before and after the movement of the intake side switching drive shaft 71, thereby taking in air. The valve operating characteristics can be accurately determined from the moving state of the side switching drive shaft 71.
The same applies to the exhaust side switching drive shaft 81.

Since the variable valve gear 40 is provided in the internal combustion engine E mounted on the motorcycle 500, the valve operating characteristic determining means 100 changes the valve operating characteristics from the moving state of the intake side switching drive shaft 71 and the exhaust side switching drive shaft 81. When it is judged that the movement is not completed normally, the output of the internal combustion engine E is suppressed to reduce the vehicle speed and the vehicle is driven, which is an unnecessary load on the internal combustion engine. Can be reduced.

Although the variable valve gear 40 according to the embodiment of the present invention has been described above, the embodiment of the present invention is not limited to the above embodiment, and is carried out in various embodiments within the scope of the gist of the present invention. It includes what is done.

Pu ... power unit, E ... internal combustion engine, M ... transmission,
1 ... Crankcase, 1L ... lower crankcase, 1L F _... front wall, 1U ... upper crankcase, 1U F _... front wall, 1U L _... left wall, 2: cylinder block, 2 F _... front wall, _{2 L} ... Left side wall, 3 ... Cylinder head, 3L ... Lower cylinder head, 3U ... Upper cylinder head, 3v ... Bearing wall, 3c ... Cam chain chamber, 4 ... Cylinder head cover, 5 ... Oil pan, 7 ... Stud bolt,
10 ... crankshaft, 11 ... main shaft, 12 ... counter shaft,
20 ... oil pump, 21 ... oil filter,
30 ... Combustion chamber, 33 ... Camshaft holder, 38 ... Cylindrical member,
40 ... Variable valve gear,
41 ... Intake valve, 42 ... Intake side camshaft, 43 ... Intake side cam carrier, 43A ... High speed side cam lob, 43B ... Low speed side cam lob, 43D ... Lead groove cylindrical part, 44 ... Lead groove, 44c ... Steady lead groove, 44l … Left shift lead groove, 44r… Right shift lead groove, 47… Intake side driven gear,
51 ... Exhaust valve, 52 ... Exhaust side camshaft, 53 ... Exhaust side cam carrier, 53A ... High speed side cam lob, 53B ... Low speed side cam lob, 53D ... Lead groove cylindrical part, 54 ... Lead groove, 54c ... Steady lead groove, 54l … Left shift lead groove, 54r… Right shift lead groove, 57… Exhaust side driven gear, 61… Idle gear, 62… Idle chain sprocket, 66… Cam chain,
70 ... Intake side cam switching mechanism, 71 ... Intake side switching drive shaft, 71C ... Cam surface, 71Cv ... Concave curved surface, 71Cp ... Flat surface, 71a, 71b ... Detected part, 71a0, 71b0 ... Recess, 71a1, 71b1 ... Outside Part, 72 ... Intake rocker arm, Ca ... Cam mechanism, 73 ... 1st switching pin, 74 ... 2nd switching pin, 75 ... Coil spring, 76 ... Lid member, 77 ... Intake side hydraulic actuator, 78 ... Intake side actuator housing, 79 ... Intake side actuator drive body, 79h ... Long hole,
80 ... Exhaust side cam switching mechanism, 81 ... Exhaust side switching drive shaft, 81v ... Recessed, 82 ... Exhaust rocker arm, Cb ... Cam mechanism, 83 ... 1st switching pin, 84 ... 2nd switching pin, 86 ... Lid member, 87 ... Exhaust side hydraulic actuator, 88 ... Exhaust side actuator housing, 89 ... Exhaust side actuator drive body, 89h ... Long hole,
91 ... Linear solenoid valve, 92 ... Solenoid solenoid,
100 ... Valve operating characteristic judgment means,
Sia, Sib ... Intake side limit switch, Sea, Sub ... Exhaust side limit switch.

Claims (6)

A camshaft (42) rotatably provided on the cylinder head (3) of the internal combustion engine (E), and
A cylindrical member that is slidably fitted in the axial direction with relative rotation prohibited on the outer circumference of the camshaft (42), and a plurality of camlobs (43A, 43B) having different cam profiles are axially mounted on the outer peripheral surface. A cam carrier (43) formed adjacent to the cam carrier (43) and a lead groove (44,54) formed so as to go around the outer peripheral surface.
Switching pins (73,74) that move forward and backward so that they can engage and disengage from the lead groove (44),
A switching drive shaft (71) for driving the switching pin (73,74) is provided.
The axial movement of the switching drive shaft (71) advances and retreats the switching pin (73,74), and the lead groove (44) in which the switching pin (73,74) advances and engages causes the cam carrier. Variable movement that constitutes the cam switching mechanism (70) that changes the valve operating characteristics by switching the cam lobs (43A, 43B) that operate on the valve (41) as the (43) is guided and shifted in the axial direction while rotating. In the valve device (40)
A plurality of detected portions (71a, 71b) provided on the switching drive shaft (71) apart from each other in the axial direction,
Sensors (Sia, Sib) that detect the states of the plurality of detected parts (71a, 71b) at predetermined positions, respectively.
A valve operating characteristic determining means (100) for determining the operating valve operating characteristic from the moving state of the switching drive shaft based on the detection results of the plurality of sensors (Sia, Sib), and
With
The valve operating characteristic determination means (100) is
Before and after the movement of the switching drive shaft (71), it is determined whether or not there is a change in the detection results of each of the plurality of sensors (Sia, Sib), and the switching drive shaft (71) is moved. A variable valve gear that determines the valve operating characteristics during operation from the state. The detected portion (71a, 71b) is an outer portion (71a1, 71b1) on both sides of a recess (71a0, 71b0) provided on the side surface of the switching drive shaft (71) and an opening of the recess (71a0, 71b0). Formed by,
1. The sensor (Sia, Sib) identifies and detects different states of the recess (71a0, 71b0) and the outer portion (71a1, 71b1) of the switching drive shaft (71). The variable valve gear described in. The switching drive shaft (71) is provided with two detected portions (71a, 71b).
The two sensors (Sia, Sib) detect the respective states of the two detected portions (71a, 71b).
Prior to the movement of the switching drive shaft (71), one of the sensors (Sia) detects the outer portion (71a1) of one of the detected portions (71a), and the other sensor (Sib) detects the other. Detects the recess (71b0) of the detected part (71b) and
After the switching drive shaft (71) moves, one of the sensors (Sia) detects the recess (71a0) of one of the detected portions (71a), and the other sensor (Sib) detects the other. The variable valve gear according to claim 2, wherein the outer portion (71b1) of the portion (71b) is detected. The valve operating characteristic determination means (100) is
When the switching drive shaft (71,81) moves normally, a predetermined time (Dt) equal to or longer than the time from the start of the movement to the completion of the movement is set in advance.
The detection result of the sensor (Sia, Sib), assuming that the switching drive shaft (71) has been moved after the predetermined time (Dt) has elapsed from the cam switching instruction time point (To) of the switching drive shaft (71). Is read, and whether or not there is a change in the detection result of the sensor (Sia, Sib) before and after the movement of the switching drive shaft (71) is determined, and the valve operating characteristic is determined from the moving state of the switching drive shaft (71). The variable valve gear according to any one of claims 1 to 3, wherein the variable valve gear is determined. The variable valve according to claim 4, wherein the predetermined time (Dt) is set as twice the time required from the cam switching instruction time point (To) to the switching of the valve operating characteristics (dt). Device. The variable valve gear according to any one of claims 1 to 5, wherein the variable valve gear (40) is provided in an internal combustion engine (E) mounted on a vehicle.

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