JP4016617B2 - Valve operating device and internal combustion engine provided with the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve operating apparatus that variably controls a lift amount, a lift timing, and a working angle of a valve in accordance with an accelerator opening in an internal combustion engine in a motorcycle or an automobile.
[0002]
[Prior art]
In this type of internal combustion engine, various ideas or proposals have been made in order to improve the combustion efficiency. Beginning with a variable phase system in which the valve opening and closing timing is shifted, variable control of the valve lift by switching the cam, valve suspension, and the like have been adopted. In this cam switching system, two cams for low speed and high speed are prepared, and the cam is switched from a small operating angle to a large one according to the engine output.
[0003]
More recently, a combination of variable phase and cam switching has begun to appear, and thereafter a method using a three-dimensional cam that continuously varies the operating angle and lift amount has been proposed.
For example, there is a type in which a follow-up mechanism for a change in contact angle is provided at the top of a direct hitting cylindrical tappet, and a valve lift is steplessly varied by sliding a three-dimensional cam in the axial direction.
[0004]
In this conventional example, since the camshaft itself is moved, it is necessary to smoothly operate both rotation and slide. In that case, since the driven sprocket cannot be slid, a hydraulic device having a large output is provided in the driven sprocket portion.
[0005]
[Problems to be solved by the invention]
However, in such a conventional example, since a large hydraulic device is required as described above, not only the overall device becomes large, but also when the phase is made variable, both are controlled in order to accurately control both. Must be systematized separately to control operation, and the cost and weight must be increased.
Moreover, in order to rotate to a high rotation range, the contact angle change follower must be reduced in weight, and when the amount of swinging is increased, the PV value is increased, and seizure is facilitated. Therefore, the lift change width is easily limited, and it is difficult to effectively cover the range of 0 to the maximum lift amount.
[0006]
Furthermore, since it is a three-dimensional (three-dimensional) cam that is formed using a flat cylindrical grinder at the time of manufacture, the contact portion is linear, and the intermediate lift curve is a curve that linearly connects the minimum to maximum lift curves. The timing and lift curve cannot be chosen freely.
In addition, since it does not have a valve pause mechanism (it is difficult to attach), swirl and tumble at low and medium speeds cannot be generated to increase the flow velocity.
[0007]
In view of such circumstances, the present invention provides a valve operating apparatus that optimally controls a valve, exhibits an excellent effect in improving fuel consumption, etc., and always guarantees proper and smooth operation and realizes high safety, and an internal combustion engine equipped with the same The purpose is to provide.
[0008]
[Means for Solving the Problems]
A valve operating device according to the present invention includes a cam formed so that a cam height and a cam operating angle continuously change, and is configured to rotate integrally with a cam shaft and be relatively movable in an axial direction thereof, and the cam of the cam A valve operating device comprising a valve lifter that is pressed by a surface to move the valve forward and backward, This valve operating device A cam surface inclined in the axial direction of the camshaft; And By sliding in the axial direction of the camshaft, the valve lift amount, valve lift timing and valve operating angle are variably controlled continuously. With cam , The cam is slid by engaging with the cam and slidingly moving in parallel with the camshaft under the driving force of the accelerator motor. Fork, A fork regulating mechanism that is capable of regulating advancing and retreating of the valve lifter when the accelerator is in a low opening degree and is driven in conjunction with a driving device different from the accelerator motor; With By driving the fork restricting mechanism according to the accelerator opening, the restricting member of the fork restricting mechanism is engaged with the fork to restrict the sliding movement of the fork. It is characterized by that.
[0009]
Further, in the valve gear of the present invention, when the valve has at least two valves and one of the valves is in a resting state, the sliding amount of the fork is within a predetermined range so that the valve lift amount by the cam does not exceed a predetermined value. It is characterized by limiting to.
[0010]
Further, in the valve operating apparatus of the present invention, it has a tappet stopper for resting the one valve, and the regulating member is formed in an approximately L shape, and is parallel to the camshaft at the corner of the L shape. One end of the restricting member is always in contact with the tappet stopper, and the other end is accessible to an accelerator shaft that supports the fork.
[0011]
Further, in the valve operating apparatus according to the present invention, when the one valve is stopped by the tappet stopper, one end side of the regulating member swings along the outer peripheral surface of the tappet stopper, and the other end side approaches the accelerator shaft. It was made to do.
[0012]
The internal combustion engine of the present invention is an internal combustion engine in which intake and exhaust are controlled by an intake valve and an exhaust valve, and is characterized in that any one of the above valve operating devices is provided on the intake side.
[0013]
The internal combustion engine of the present invention includes a steering head pipe that pivotally supports a front fork, a fuel tank that is mounted on a vehicle body frame that is connected to the steering head pipe, and a rear side of the fuel tank. In a motorcycle having a seat and an air cleaner disposed below the seat and the fuel tank, the intake pipe is connected to an air intake pipe that is mounted in front of the air cleaner and connects the rear part and the air cleaner. Is an internal combustion engine having an exhaust pipe coupled to the opposite side of the engine, and is formed such that the cam height and the cam working angle continuously change, and can rotate integrally with the camshaft and relatively move in the axial direction thereof. A valve operating device comprising: a cam configured as described above; and a valve lifter that is pressed against the cam surface of the cam to advance and retract the valve; This valve operating device A cam surface inclined in the axial direction of the camshaft; And By sliding in the axial direction of the camshaft, the valve lift amount, valve lift timing and valve operating angle are variably controlled continuously. With cam , The cam is slid by engaging with the cam and slidingly moving in parallel with the camshaft under the driving force of the accelerator motor. Fork, A fork restricting mechanism that is capable of restricting the advance / retreat of the valve lifter when the accelerator is in a low opening degree and that is driven in conjunction with a drive device different from the accelerator motor; With By driving the fork restricting mechanism according to the accelerator opening, the restricting member of the fork restricting mechanism is engaged with the fork to restrict the sliding operation of the fork. It is characterized by that.
[0014]
According to the present invention, in this type of engine, the valve lift amount and the operating angle are variably controlled in accordance with the accelerator opening. In this case, the intake air amount can be controlled from the idling speed range to the fully open range, and the intake characteristics most suitable for the engine speed can be secured. As a result, combustion efficiency can be effectively increased, fuel efficiency and output can be significantly improved, and the structure is relatively simple and exhibits an excellent effect, so that it does not cost substantially and is easy to manufacture.
[0015]
In particular, by having a restricting member that variably controls the sliding amount of the fork according to the accelerator opening, a range in which the fork can slide according to the accelerator opening is limited. As a result, the cam can be controlled so that the valve lift amount is optimal for the accelerator opening.
Further, when one of the valves is stopped by the tappet stopper, the frictional resistance that can be generated between the valve lifter and the tappet guide is reduced by restricting the valve lift amount by the cam, and the operation of the valve lifter is made smooth.
Further, by always bringing one end of the restricting member into contact with the tappet stopper, the switching control of the restricting member can be accurately synchronized with the tappet stopper to ensure smooth and proper operation.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
The valve gear according to the present invention can be effectively applied to various gasoline engines mounted on a motorcycle or a four-wheeled vehicle. In this embodiment, for example, as shown in FIG. 1, a motorcycle engine is taken as an example. To do.
[0017]
First, the overall configuration of the motorcycle 100 according to the present embodiment will be described. In FIG. 1, two front forks 103 supported by a steering head pipe 102 so as to be turnable to the left and right are provided at a front portion of a body frame 101 made of steel or an aluminum alloy material. A handle bar 104 is fixed to the upper end of the front fork 103, and grips 105 are provided at both ends of the handle bar 104. A front wheel 106 is rotatably supported on the lower portion of the front fork 103, and a front fender 107 is fixed so as to cover the upper portion of the front wheel 106. The front wheel 106 has a brake disc 108 that rotates integrally with the front wheel 106.
[0018]
A swing arm 109 is swingably provided at the rear portion of the vehicle body frame 101, and a rear shock absorber 110 is mounted between the vehicle body frame 101 and the swing arm 109. A rear wheel 111 is rotatably supported at the rear end of the swing arm 109, and the rear wheel 111 is rotationally driven via a driven sprocket 113 around which a chain 112 is wound.
[0019]
The engine 1 (solid line portion) mounted on the vehicle body frame 101 is supplied with an air-fuel mixture from an intake pipe 115 coupled to an air cleaner 114, and exhaust gas after combustion is exhausted through an exhaust pipe 116. The air cleaner 114 is installed in a large space behind the engine 1 and below the fuel tank 117 and the seat 118 to secure capacity. Therefore, the intake pipe 115 is coupled to the rear side of the engine 1, and the exhaust pipe 116 is coupled to the front side of the engine 1. A fuel tank 117 is mounted above the engine 1, and a seat 118 and a seat cowl 119 are connected to the rear of the fuel tank 117.
[0020]
Here, an accelerator motor 45 to be described later is attached to a predetermined portion of the cylinder head 2 to the cylinder head cover 2a of the engine 1. The accelerator motor 45 is projected from the upper surface of the cylinder head cover 2a, for example, as shown in the figure. In that case, the accelerator motor 45 is arranged in a recess provided in the lower part of the fuel tank 117, and the fuel tank 117 and the cylinder head cover 2a are arranged so as not to interfere with each other.
[0021]
The accelerator motor 45 can be installed either on the intake side or on the exhaust side if a link is used. However, if the accelerator motor 45 is provided on the exhaust side, the recess formed in the fuel tank 117 is exposed, and the appearance deteriorates as it is. It is preferable to provide the accelerator motor 45 on the intake side.
[0022]
Further, in FIG. 1, 120 is a headlamp, 121 is a meter unit including a speedometer, tachometer, or various indicator lamps, and 122 is a rearview mirror supported by the handlebar 104 via a stay 123. A main stand 124 is swingably attached to the lower part of the body frame 101, and the rear wheel 111 can be grounded or floated from the ground. The body frame 101 extends obliquely downward and rearward from the head pipe 102 provided at the front part, and is bent so as to wrap the lower part of the engine 1, and then forms a pivot 109 a that is a pivotal support part of the swing arm 109. The rail 101a and the seat rail 101b are connected.
[0023]
The vehicle body frame 101 is provided with a radiator 125 in parallel with the vehicle body frame so as to avoid interference with the front fender 107, and a cooling water hose 126 is provided along the vehicle body frame 101 from the radiator 125, and an exhaust pipe 116. It communicates with the engine 1 without interfering with.
[0024]
2 is a sectional side view of the main part of the device of the present invention, and FIG. 3 is a sectional view taken along the line AA in FIG. As shown in these figures, this embodiment is a parallel two-cylinder engine, and each cylinder has two valves (that is, four valves) on the intake side (IN) and the exhaust side (EX). ing. In this embodiment, the example is applied to the intake side, but it can also be applied to both the intake side and the exhaust side. A cylinder head 2 is disposed on an upper portion of a piston 1 that reciprocates up and down in the cylinder, and a valve gear is accommodated in the cylinder head 2.
[0025]
The valve operating apparatus includes a cam / camshaft unit 10 disposed along the cylinder arrangement direction, a tappet unit 20 disposed below the cam / camshaft unit 10, and a valve unit 30 that controls intake air in this example. And an accelerator shaft unit 40 that displaces the cam in accordance with the accelerator opening, and a valve pause unit 50 that pauses the valve as necessary. The valve unit 30 may have the same configuration on the exhaust side.
[0026]
In the cam / camshaft unit 10, the camshaft 11 is rotatably supported by the cylinder head 2 via a bearing 12 (FIG. 3). A cam 13 which will be described later is slidably mounted on the cam shaft 11 in the axial direction. In this example, the cam shaft 11 has, for example, three ball splines 11a, and linearly moves through the balls 14 by the guides. (Linear motion). The camshaft 11 has a hollow structure, and a lubricating oil passage can be formed in the hollow to lubricate the cam 13 or the like.
[0027]
A sprocket 15 is fixed to one end of the camshaft 11. Exhaust camshaft 11 _Ex One end of the sprocket 15 _Ex Are fixed, and these sprockets 15 and 15 _Ex And a cam chain 5 is wound around the drive sprocket 4 fixed to one end of a crankshaft (not shown) (see FIG. 5). In addition, as shown in FIG. 5, the chain guide 6, the chain tensioner 7, the chain adjuster 8, and the like are included so that the cam chain 5 can travel appropriately.
[0028]
Here, the cam 13 is configured as a so-called “three-dimensional cam”, and one cam 13 is provided for each cylinder. As shown in FIG. 6, a cam portion 13a that is gently inclined in the longitudinal direction (the axial direction of the camshaft 11) extends and is formed into a shape that continuously changes the valve lift amount. In this case, the cam operating angle and the lift timing change simultaneously with the cam height, that is, the cam operating angle increases as the valve lift amount increases, and the valve lift timing can also be changed. FIG. 7 shows an example of specific three-dimensional cam configuration specifications of the cam 13. By moving the cam 13 along the camshaft 11, the lift amount, operating angle, and lift timing of the intake valve can be variably controlled steplessly.
[0029]
In the tappet unit 20, the tappet 21 is formed in a disc shape (doughnut shape) having an accommodating portion for accommodating a bearing inside, and holds the tappet core material 23 via a ball 22 as a bearing. A tappet holder 24 is disposed and fixed at an appropriate position of the cylinder head 2, and the tappet 21 is floated and held while being accommodated inside the tappet holder 24. The tappet unit 20 (tapet 21) functions as a valve lifter that is pushed by the cam surface of the cam 13 to advance and retract the valve.
[0030]
The tappet core member 23 is provided at a base portion 23a for accommodating and holding the ball 22 together with the tappet 21, an arm portion 23b extending from the base portion 23a to the left and right sides (in the camshaft direction), and an end portion of each arm portion 23b. And a pressing portion 23c adapted to abut. The two valves can be driven simultaneously by one tappet 21 through the pressing portion 23c.
[0031]
The outer peripheral surface of the tappet 21 is typically formed in an arc shape (R shape) and is in point contact with the cam 13. Further, the ball 22 is interposed between the tappet 21 and the base portion 23a of the tappet core 23, thereby providing an automatic alignment function. The arm portion 23 b of the tappet core member 23 is guided by a guide groove 24 a (see FIG. 2) provided in the tappet holder 24. The guide of the tappet holder 24 allows the tappet 21 to move only in the axial direction of the valve stem 31a.
[0032]
In this embodiment, on the exhaust side, as shown in FIG. _Ex A disk-shaped tappet 21 having a (planar cam) and a contact plane abutting on it. _Ex Have
[0033]
In the valve unit 30, each valve stem 31 a includes two intake valves 31 guided by a valve guide 32. Each valve stem 31 a has a tappet shim 33 in contact with the pressing portion 23 c of the tappet core 23, and a valve spring 36 is mounted between the valve retainer 34 and the spring seat 35.
[0034]
The accelerator shaft unit 40 includes an accelerator shaft 41 disposed in parallel with the camshaft 11 and an accelerator fork 42 that is fixed to the accelerator shaft 41 and connected to the cam 13. The accelerator shaft 41 is supported by the cylinder head 2 so as to be slidable in the axial direction, and is engaged with a driven gear 43 (wheel) via a screw respline 41a on one end side. The driven gear 43 is rotatably supported by a double row ball bearing 44 and meshes with a drive gear 46 (worm) fixed to the output shaft of the accelerator motor 45.
[0035]
The accelerator motor 45 rotates its output shaft in response to accelerator changes (accelerator opening, acceleration / deceleration direction, etc.), and the rotation is converted into a sliding motion of the accelerator shaft 41 via the drive gear 46 and the driven gear 43. Is done. In this example, the accelerator motor 45 is disposed along the cylinder axis direction and is covered by the cylinder head cover 2a.
For example, in the case of a motorcycle, the rotational operation amount of the accelerator grip may correspond to the rotational amount of the output shaft of the accelerator motor 45. Further, when the accelerator motor 45 is driven, it is driven and controlled by a controller (not shown) so as to match the traveling state (output) at that time.
[0036]
The accelerator fork 42 engages with a fork guide 48 that is rotatably mounted on the end of the cam 13 via a bearing 47. As a result, the cam 13 slides along the camshaft 11 in conjunction with or in synchronization with the accelerator shaft 41 sliding in the axial direction.
[0037]
Here, in the present invention, as shown particularly in FIG. 3, a stopper collar 49 is fitted to the accelerator shaft 41. As will be described later, the stopper collar 49 is engaged with an accelerator fork restricting mechanism 70 to restrict the sliding operation of the accelerator fork 42.
[0038]
The valve pause unit 50 includes a tappet stopper 51 configured to pause one of the two intake valves 31. The tappet stopper 51 is inserted in a guide hole 2 c formed in the cylinder head 2 and can slide in parallel with the camshaft 11. One end of the tappet stopper 51 has a spherical stopper 51a that can be engaged with the fitting recess 23d of the tappet core 23, and the other end is attached with a fork guide 52 that engages a fork described later. . A return spring 53 that urges the stopper 51a toward the fitting recess 23d of the tappet core 23 is mounted in the guide hole 2c.
[0039]
The drive device 54 is arranged in parallel with the camshaft 11 and advances and retracts a drive shaft 55 for driving the tappet stopper 51 (advance / retreat drive). A fork 56 is coupled to the drive shaft 55, and the fork 56 engages with the fork guide 52 of the tappet stopper 51. The two tappet stoppers 51 are connected to each other by a drive shaft 55 so as to operate synchronously.
[0040]
The valve deactivation unit 50 is particularly effective for generating an intake swirl flow in the combustion chamber in the engine low-speed rotation range. That is, the tappet stopper 51 serves as a fulcrum on one end side of the tappet core 23 at the low engine speed, and the other end side. Only the pressing portion 23c pushes the intake valve 31 down, that is, lifts it, thereby generating a swirl flow.
[0041]
Here, a phase sensor unit 60 is provided at the other end of the camshaft 11. The phase sensor unit 60 includes a pin 61 implanted in the other end of the camshaft 11 and a phase sensor 62 that detects the pin 61 and obtains an output signal.
[0042]
In the present invention, an accelerator fork restricting mechanism 70 for variably controlling the slidable amount of the accelerator fork 42 according to the accelerator opening is provided (FIG. 2). The accelerator fork restricting mechanism 70 has an approximately L shape, and has a sensor arm 71 that functions as a position sensor for the tappet stopper 51 on one end side of the L shape as shown in FIG. A restriction arm 72 that functions as a restriction member for the accelerator fork 42 is provided. The sensor arm 71 and the regulation arm 72 are fixed to both ends of the rotating shaft 73 and are integrally formed. The rotating shaft 73 may be pivotally supported using a part of the tappet holder 24, for example.
[0043]
The tip 71 a of the sensor arm 71 is disposed so as to contact the tappet stopper 51 as shown in FIG. 3, and the tip 72 a of the restriction arm 72 is disposed so as to contact the stopper collar 49. A torsion coil spring 74, which is an elastic means, is mounted around the rotating shaft 73, and the tip 71a of the sensor arm 71 is always attached to the outer peripheral surface of the tappet stopper 51 by the elasticity of the torsion coil spring 74. Be forced. As shown in FIG. 8, the position of the restriction arm 72 is restricted by a stopper portion 2b on the cylinder head 2 side.
[0044]
As described above, the tip 71a of the sensor arm 71 is always in contact with the outer peripheral surface of the tappet stopper 51. Here, referring to FIG. 9, the tappet stopper 51 is connected to the stopper portion 51a so as to be connected to the neck portion 51b and the inclined surface portion. 51c and a large diameter portion 51d. As the tappet stopper 51 advances and retreats with respect to the tappet core member 23, the contact position of the tip 71a of the sensor arm 71 with respect to the tappet stopper 51 sequentially changes between the neck portion 51b and the large diameter portion 51d. Further, the change in the contact position of the tip 71a of the sensor arm 71 causes the tip 72a of the restricting arm 72 to approach and separate from the accelerator shaft 41 (in the radial direction of the accelerator shaft 41).
[0045]
The elasticity of the torsion coil spring 74 is set to the minimum necessary for restricting the movement of the sensor arm 71 or the restricting arm 72 due to vibration generated during traveling. As a result, the tip 71a of the sensor arm 71 comes into contact with the tappet stopper 51 with an appropriate amount of force, and the smooth operation of the tappet stopper 51 is guaranteed.
[0046]
In the above configuration, when the accelerator grip (or accelerator pedal) is operated, the accelerator motor 45 is operated, and the accelerator shaft 41 is slid by the rotation of the output shaft. For example, as shown in FIG. 3, when the engine speed is low, the tappet 21 is in contact with the cam 13 at a portion where the cam height is low. When acceleration is performed in this state, that is, the accelerator is opened, the driven gear 43 is rotated by the operation of the accelerator motor 45, and the accelerator shaft 41 slides to the right in the drawing. The cam 13 slides rightward in the figure along the camshaft 13 in conjunction with the movement of the accelerator shaft 41 via the accelerator fork 42. At this time, the sliding amount and speed of the cam 13 correspond to the accelerator opening and the opening speed. As the cam 13 slides, the tappet 21 gradually comes into contact with a portion having a high cam height, whereby the valve lift amount increases in accordance with the lift characteristics shown in FIG. On the other hand, by returning the accelerator at the time of deceleration, the valve lift amount is reduced by the reverse operation to the above.
[0047]
Here, in the valve gear or internal combustion engine of the present invention described above, first, the three-dimensional cam 13 is slid on the camshaft 11 in the axial direction. As a result, by reducing the width of the cylinder head 2 of the cam shaft portion, it is possible to reduce the weight and size. Further, by separating the rotary bearing (bearing 12) of the camshaft 13 and the slide bearings (ball spline 11a and ball 14) of the cam 13, both of them are constituted by rolling bearings, so that the cam 13 can be made with a very small force. It can be displaced smoothly.
[0048]
Furthermore, in addition to the slide mechanism of the cam 13, a cam timing changing mechanism can be added. In this case, for example, by providing a so-called continuously variable valve timing mechanism (referred to as “VVT mechanism” or the like) around the sprocket 15, it can be effectively performed without increasing the size and cost of the apparatus. Since the camshaft 13 itself does not slide for changing the cam timing, the phase sensor unit 60 can be used effectively.
[0049]
Further, as described above, the slide bearing portion of the cam 13 is configured by the rolling bearing by the ball spline 11a, so that the slide resistance is remarkably reduced as compared with the case of the slip resistance. Thereby, the accelerator motor 45 can be reduced in size, and the power consumption when the accelerator is variable can be reduced. Rolling bearings have advantages such as less seizure even with lighter lubrication than sliding bearings.
[0050]
Also, by sliding the cam 13 through a plurality of (for the number of cylinders) accelerator forks 42 fixed to one accelerator shaft 41, all the cams 13 can be accurately synchronized, and the valves of the plurality of cylinders can be adjusted. Tuning control is possible. Also, by providing a single cam 13 for each cylinder, a large cam width (in the camshaft direction) can be secured, and the inclination angle of the cam 13 forming the valve lift curve can be set loosely. As a result, the sliding load of the cam 13 can be reduced, and the accelerator motor 45 can be downsized in this respect as well, and a highly accurate accelerator work can be realized.
[0051]
Further, by connecting the accelerator fork 42 and the cam 13 through the bearing 47 so as to be rotatable, it is possible to prevent seizure of the rotating portion up to the high rotation region of the cam 13. In addition, by reducing the rotational resistance of the rotating part, mechanical loss (mechanical loss) that occurs during valve drive is reduced.
[0052]
Further, the outer peripheral contact surface of the tappet 21 is formed in a curved surface, and the cam 13 and the tappet 21 are always brought into point contact with each other by allowing the stroke in the valve stem axial direction to be slidable and rotatable. As a result, the cam characteristics including the cam height (valve lift amount), operating angle, timing, etc. of the cam 13 can be formed in a three-dimensional map, and the optimum lift characteristics are set for the engine speed and torque, Mirror cycle can be realized freely at low and medium speeds. Further, the tappet 21 and the cam 13 or the tappet shim 33 are in contact with each other in a rolling manner, and are not always in contact at a single point. Therefore, the tappet 21 is excellent in wear resistance and can greatly improve durability. . This effectively realizes high engine rotation.
[0053]
Further, a tappet core member 23 having an automatic centering function is provided on the center axis of the tappet 21, guided by the guide groove 24 a of the tappet holder 24, and the two intake valves 31 at the pressing portions 23 c at both ends of the tappet core member 23. Make it liftable. By lifting the two valves with a single tappet 21, the tappet weight can be reduced, and high rotation and compactness can be achieved. In this case, the contact between the tappet 21 and the cam 13 or the tappet shim 33 is a rolling contact and thus has excellent wear resistance. Further, since the load or load other than the axial direction does not act on the valve stem 31a of each intake valve 31, wear of the valve guide 32 and the tappet guide is reduced, and the valve stem 31a can be substantially reduced in diameter. It is advantageous for rotation and high output. Further, since the automatic alignment mechanism is constituted by a rolling bearing using the balls 22, it can be lubricated without being seized even by splash lubrication, so that a special lubricating oil pumping device is not required, the structure is simplified and the durability is improved.
[0054]
Further, the valve pause unit 50 can pause one intake valve 31 by the tappet stopper 51. By this valve stop, an intake swirl flow or a tumble flow is generated in the combustion chamber in the low / medium speed rotation region of the engine, and so-called lean burn is enabled. In this case, the output can be increased by increasing the fuel injection speed.
[0055]
Here, when the valve is stopped, for example, as shown in FIG. 3, the pressing portion 23c on the other intake valve 31 side is pushed down with the contact portion with the tappet stopper 51 as a fulcrum, and the tappet core member 23 swings. The normal valve lift amount x that lifts both intake valves 31 is the valve lift amount y when the valve is at rest, that is, the lift amount increases (y / x) times. When the valve is inactive, intake is performed by one of the ports, which in itself increases the intake resistance, but the effective valve opening area is increased by increasing the lift amount. As a result, the difference in intake amount due to the valve opening area and the intake resistance at the time of ON / OFF switching of the valve pause can be substantially eliminated, or smooth switching can be performed with a small amount.
[0056]
Since the tappet stopper 51 is typically spherical, it functions smoothly and properly as a fulcrum for the pressing portion 23c. Since the position of the spherical fulcrum is determined by the accuracy of the hole machining pitch of the cylinder head 2, the accuracy with respect to the cam shaft is easily obtained. Further, by simplifying the configuration of the valve pause unit 50, it is possible to reduce the weight and to reduce the cost. Since the degree of freedom of the fulcrum position by the tappet stopper 51 is high, the ratio (y / x) of the valve lift amount can be set relatively freely. For example, by setting the ratio on the center of the valve stem 31a, y / x = 2.
[0057]
Now, especially in the device of the present invention, when the valve is stopped, the stopper 51a of the tappet stopper 51 is fitted into the fitting recess 23d of the tappet core 23 as shown in FIG. 71 a abuts on the large diameter portion 51 d of the tappet stopper 51. As a result, the distal end 72a of the restricting arm 72 approaches the accelerator shaft 41 and rotates to a position where it can come into contact with the stopper collar 49 as shown in FIG. That is, only the distance or length S is given as the sliding amount of the accelerator fork 42 as shown in the figure, and is limited to the tappet stroke corresponding to the distance S.
[0058]
In this case, when the accelerator fork 42 is slid by the distance S, the lift side valve lift amount that is (y / x) times as large as the cam peak maximum lift amount is set so that the valve and the piston do not touch each other (the maximum at the time of normal double valve lift). Set the lift amount below. At the same time, the valve lift amount corresponding to (y / x) times the cam peak maximum lift amount is set within the allowable alignment angle (inclination angle) of the automatic alignment function performed by the tappet core member 23 swinging. Keep it.
[0059]
By setting the relationship between the distance S and the valve lift amount as described above, it is possible to reliably prevent the lift side valve from being lifted beyond the safe range when the valve is stopped. For example, even if a return failure of the tappet stopper 51 or a malfunction or malfunction of the actuators occurs, it is possible to prevent the valve and the piston from colliding or the tappet core 23 from malfunctioning. Safety can be ensured and maintained.
[0060]
On the other hand, at the time of both valve lifts, when the tappet stopper 51 is retracted from the tappet core 23 by the drive device 54 via the drive shaft 55, the stopper portion 51a of the tappet stopper 51 is turned into a tappet as shown in FIG. The core 23 is separated from the fitting recess 23d. The tip 71 a of the sensor arm 71 contacts the neck 51 b of the tappet stopper 51. As a result, the distal end 72a of the restricting arm 72 is separated from the accelerator shaft 41 (FIG. 4), and the accelerator fork 42 and therefore the cam 13 can freely slide to the maximum valve lift amount.
[0061]
The length of the stopper collar 49 is set such that the tip 72a of the restricting arm 72 can contact the stopper collar 49 even when the accelerator shaft 41 slides to the maximum. Thus, even when the urging force of the torsion coil spring 74 is not effective, the accelerator can be returned to the original state.
[0062]
Further, as described above, the stopper portion 2b (see FIG. 8) is provided on the side that receives the sliding force of the accelerator shaft 41 when the tip 72a of the regulating arm 72 contacts the stopper collar 49. Since the sliding force of the accelerator shaft 41 is received by the stopper portion 2b, the sliding force acts in the direction in which the rotating shaft 73 is pressed against the tappet holder 24 by the lever principle. Thereby, the pull-out strength of the rotating shaft 73 can be set substantially low, and a reduction in size and weight can be achieved.
[0063]
As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
For example, the specific numerical examples and the like described in the above embodiment (for example, the three-dimensional cam configuration specifications shown in FIG. 7) are not necessarily limited to this, and can be changed as necessary. In each embodiment, an example of a two-cylinder engine has been described. However, the present invention can be effectively applied to a single-cylinder engine or a three-cylinder or more engine.
[0064]
【The invention's effect】
As described above, according to the present invention, the valve lift amount, the operating angle, and the lift timing are variably controlled in accordance with the accelerator opening in this type of valve operating device. In this case, the cam can be controlled so that the valve lift amount is optimum for the accelerator opening degree by having a restricting member that variably controls the sliding amount of the fork according to the accelerator opening degree. Further, when one of the valves is stopped by the tappet stopper, the frictional resistance that can be generated between the valve lifter and the tappet guide is reduced by restricting the valve lift amount by the cam, and the operation of the valve lifter is made smooth. And, it has advantages such as ensuring high safety while maintaining such excellent functions and operating characteristics.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a motorcycle including an engine periphery according to an application example of the invention.
FIG. 2 is a cross-sectional side view of a main part of the valve gear of the present invention.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a cross-sectional side view of a main part of the valve gear of the present invention.
FIG. 5 is a diagram showing a camshaft rotational drive system according to the valve gear of the present invention.
FIG. 6 is a perspective view showing a three-dimensional cam according to the valve gear of the present invention.
FIG. 7 is a view showing an example of specific three-dimensional cam configuration specifications of the cam according to the valve gear of the present invention.
8 is a cross-sectional view taken along line BB in FIG.
FIG. 9 is a diagram for explaining the operation of an accelerator fork regulating mechanism in the valve gear of the present invention.
[Explanation of symbols]
1 engine
2 Cylinder head
4 Drive sprocket
5 Cam chain
6 Chain guide
7 Chain tensioner
8 Chain adjuster
10 Cam / Camshaft unit
11 Camshaft
12 Bearing
13 cams
20 tappet units
21 Tappet
22 balls
23 Tappet core
24 Tappet holder
30 Valve unit
31 Intake valve
32 Valve guide
33 Tappet Sim
34 Tappet retainer
35 Spring seat
36 Valve spring
40 Accelerator shaft unit
41 Accelerator shaft
42 Accel Fork
43 Driven Gear
44 Ball bearing
45 Accelerator motor
46 Drive gear
50 Valve deactivation unit
51 Tappet stopper
52 Rotating shaft
53 Drive unit
54 Swing arm
60 Phase sensor unit
61 pin
62 Phase sensor
71 Sensor arm
72 Regulating arm
73 Rotating shaft
74 Torsion coil spring

Claims (6)

The cam height and cam operating angle are formed so as to continuously change, and the cam is configured to rotate integrally with the cam shaft and to be relatively movable in the axial direction thereof, and the valve is moved forward and backward by being pressed by the cam surface of the cam. A valve operating device having a valve lifter
The valve operating device has a cam surface inclined in the axial direction of the camshaft, and valve lift amount by sliding in the axial direction of the camshaft, the variable in valve lift timing and valve operating angle continuous variable and a cam that will be controlled,
A fork that slides in the cam by engaging with the cam and sliding in parallel with the camshaft under the driving force of an accelerator motor ;
A fork regulating mechanism that is capable of regulating the forward and backward movement of the valve lifter when the accelerator is in a low opening, and that is driven in conjunction with a driving device different from the accelerator motor ;
A valve operating apparatus for an internal combustion engine, wherein the fork restricting mechanism is driven in accordance with an accelerator opening so that a restricting member of the fork restricting mechanism engages with the fork to restrict a sliding operation of the fork. .   2. The slide amount of the fork is limited to a predetermined range so that the valve lift amount by the cam does not exceed a predetermined value when at least two valves are provided and one of the valves is in a resting state. 2. The valve operating apparatus for an internal combustion engine according to 1. While having a tappet stopper for pausing the one valve, the regulating member is formed in an approximately L shape, and is pivotally supported in parallel with the camshaft at the corner of the L shape,
3. The valve operating apparatus for an internal combustion engine according to claim 2, wherein one end of the restricting member is always in contact with the tappet stopper, and the other end is accessible to an accelerator shaft that supports the fork.   The one end side of the restricting member swings along the outer peripheral surface of the tappet stopper and the other end side approaches the accelerator shaft when the one valve is stopped by the tappet stopper. Item 5. A valve operating apparatus for an internal combustion engine according to Item 3. An internal combustion engine configured to control intake and exhaust by an intake valve and an exhaust valve,
An internal combustion engine comprising the valve gear according to any one of claims 1 to 4 at least on an intake side. A steering head pipe that pivotally supports a front fork, a fuel tank mounted on a vehicle body frame connected to the steering head pipe, a seat connected to the rear of the fuel tank, the seat and the fuel A motorcycle having an air cleaner disposed below a tank, wherein the exhaust pipe is mounted in front of the air cleaner and connects the rear portion and the air cleaner and the exhaust pipe connected to the opposite side of the intake pipe. An internal combustion engine comprising:
The cam height and cam operating angle are formed so as to continuously change, and the cam is configured to rotate integrally with the cam shaft and to be relatively movable in the axial direction thereof, and the valve is moved forward and backward by being pressed by the cam surface of the cam. Having a valve lifter to be operated,
The valve operating device has a cam surface inclined in the axial direction of the camshaft, and valve lift amount by sliding in the axial direction of the camshaft, the variable in valve lift timing and valve operating angle continuous variable and a cam that will be controlled,
A fork that slides in the cam by engaging with the cam and sliding in parallel with the camshaft under the driving force of an accelerator motor ;
A fork regulating mechanism that is capable of regulating the forward and backward movement of the valve lifter when the accelerator is in a low opening, and that is driven in conjunction with a driving device different from the accelerator motor ;
An internal combustion engine in which the fork restricting mechanism is driven in accordance with an accelerator opening so that a restricting member of the fork restricting mechanism engages with the fork to restrict a sliding motion of the fork .

Images