JP4818314B2 - Valve timing control device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve timing control device for an internal combustion engine that makes the opening / closing timing of an intake-side or exhaust-side engine valve of the internal combustion engine variable according to the engine operating state.

  As a conventional valve timing control device, for example, one described in Patent Document 1 below is known.

In brief, this valve timing control device is configured such that a timing pulley (driving rotator) that is rotationally driven by a crankshaft of an engine is coaxial with an outer peripheral side of a shaft member (driven rotator) integrally coupled to a camshaft. The timing pulley and the shaft member are connected to each other via an assembly angle adjusting mechanism. The assembly angle adjusting mechanism is formed on a piston member (movable operation member) that is attached to the timing pulley so as to be capable of axial displacement in a state where relative rotation is restricted, and an inner peripheral surface of the piston member and an outer peripheral surface of the shaft member. The piston gear is moved forward and backward in the axial direction by a control mechanism having an electromagnet and a return spring so that the assembly angle of the timing pulley and the shaft member can be adjusted through the helical gear. adjust.
JP-A-10-153104

  However, in this conventional valve timing control device, the piston member (movable operation member) of the assembly angle adjusting mechanism is configured to advance and retract along the axial direction of the camshaft. As a result, the space occupied in the axial direction of the assembly angle adjusting mechanism in the engine increases, and the axial length of the engine becomes longer, resulting in a deterioration in vehicle mountability. In particular, in order to change the piston member advancing / retreating operation position by the electromagnet, the electromagnet must be disposed further outside in the axial direction than the advancing / retreating position of the piston member. It was impossible to install the engine.

  Therefore, the present invention is intended to provide a valve timing control device for an internal combustion engine that can reduce the space occupied in the axial direction of the assembly angle adjusting mechanism and improve the vehicle mountability.

The present invention relates to a drive rotator that is rotationally driven by a crankshaft of an engine, a driven rotator that is coaxially and relatively rotatable with respect to the drive rotator, and a spiral with a partially increased curvature. A guide plate having a guide groove, and a guide plate that is engaged with the spiral guide groove and is guided in a radial direction by the drive rotator, the guide plate being connected to the drive rotator and the driven rotator. The movable operating member provided to move in the radial direction of the guide plate, the arm provided on the driven rotating body, extending in the radial direction, and the arm and the movable connecting the operating member, characterized by comprising a link arm to vary the relative rotational phase of the drive rotor and the driven rotor by the radial movement of the movable operation member There.

  Therefore, since this movable operation member is moved along the radial direction of the drive rotator and the driven rotator, the space occupied in the axial direction of the movable operation member can be reduced.

  In addition, since the movable operation member is moved in the radial direction through the plurality of spiral guide grooves of the guide plate, a large relative rotational phase change is caused with respect to a small relative rotation between the driving rotating body and the driven rotating body. It becomes possible to obtain.

  FIG. 1 shows an embodiment in which a valve timing control device for an internal combustion engine according to the present invention is applied to an intake valve side. Note that the present invention is not limited to the intake valve side, and can be similarly applied to the exhaust valve side.

  This valve timing control device is fixed to a camshaft 1 having a cam (not shown) that is rotatably supported by a cylinder head of an engine and opens an intake valve on the outer periphery, and a front end portion of the camshaft 1. A timing sprocket 3 rotatably attached to a cylindrical retainer 2 having a stepped diameter and rotated by an engine crankshaft (not shown), and between the front end portions of the retainer 2 and the timing sprocket 3 The assembly angle adjustment mechanism 4 that is arranged and variably adjusts the assembly angle between the camshaft 1 and the timing sprocket 3 is mounted across the cylinder head 5 and the front end face of the rocker cover (not shown) to adjust the assembly angle. A VTC cover 6 that surrounds the periphery of the mechanism 4 and a controller 7 that controls the assembly angle adjusting mechanism 4 according to the operating state of the engine are provided. In this embodiment, the driving rotator is constituted by the timing sprocket 3, and the driven rotator is constituted by the camshaft 1 and the retainer 2.

  As shown in FIG. 1, the timing sprocket 3 includes a disc-shaped base 3a through which the retainer 2 is inserted in the center, an outer peripheral portion of the base 3a, and a protruding portion protruding in the axial direction from the side of the base 3a. Each toothed portion 9a, 9b provided on 8, and one end of each toothed portion 9a, 9b wound around a driving sprocket of the crankshaft and a driven sprocket of the exhaust camshaft, not shown, The other end side of the driven tune is wound. Moreover, the disk-shaped protrusion wall 10 is integrally formed in the front-end part of the base part 3a, and as shown in FIGS. 1-3, this protrusion wall 10 is 3 strips which are radial direction guide parts in the end surface. The sliding grooves 11a, 11b, and 11c are formed along the radial direction. The sliding grooves 11a, 11b, and 11c are formed in a substantially arc shape in cross section, and are arranged radially at positions of about 120 degrees in the circumferential direction, and each end thereof is an outer peripheral edge of the protruding wall 10 The movable operation member 14 is guided in the radial direction by the sliding grooves 11a, 11b, and 11c.

  As shown in FIGS. 1 and 2, the assembly angle adjusting mechanism 4 is coupled to the end of the retainer 2 in the axial direction, and extends radially to the outer periphery corresponding to the sliding grooves 11a, 11b, 11c. A lever member 12 having three arm portions 13, 13, 13 to be taken out, three movable operation members 14, 14, 14 slidably engaged with the respective sliding grooves 11a, 11b, 11c, and one end Linear link arms 15, 15, 15 having a portion integrally coupled to a base end portion of each movable operation member 14 and the other end connected to a distal end portion of each arm portion 13, and each movable operation The operation mechanism 16 is configured mainly to move the member 14 forward and backward based on a control signal from the controller 7.

  The lever member 12 has each arm portion 13 projecting from the cylindrical base end portion 12 a at an angular position of about 120 degrees in the circumferential direction, and one end portion of the base portion 12 a at the tip end portion of the retainer 2. In the fitted state, it is fastened and fixed to the camshaft 1 from the axial direction by a fixing bolt 17. In addition, the lever member 12 has a slit 13a formed at substantially the center of each arm portion 13. The other end of each link arm 16 is inserted into each slit 13a, and the pins 18, 18, 18 are inserted. It is connected via a pivot. A positioning pin 19 is fitted to the lever member 12 and the camshaft 1, and the pin 19 is used for accurate positioning of both.

  In addition, as shown in FIG. 1 to FIG. 3, each movable operation member 14 is slidably accommodated with substantially annular sliding portions 14 b and 14 c that are back to back in the hollow inside of the cylindrical portion 14 a. The sliding grooves 11a, 11b, 11c are engaged with spiral guide grooves 30, 30, 30 of a guide plate 23 described later in spherical recesses formed on the outer surfaces of the sliding parts 14b, 14c. Thus, the first guide ball 20 and the second guide ball 21 that are rolling protrusions are held so as to be freely rollable. Further, the sliding portions 14b and 14c are made to move the guide balls 20 and 21 to the sliding grooves 11a, 11b and 11c and the spiral guide grooves by the spring force of the coil springs 22 interposed therebetween. It is biased in 30 directions.

  Accordingly, when each movable operation member 14 is radially displaced along each sliding groove 11 a, 11 b, 11 c, the timing sprocket 3 and the camshaft 1 are displaced by the movement of each movable operation member 14 by the action of each link arm 15. Relative rotation by the corresponding angle.

  On the other hand, as shown in FIGS. 1 and 4, the actuation mechanism 16 is disposed to face the protruding wall 10 of the timing sprocket 3 with the movable operation members 14 interposed therebetween, and each movable operation member 14 is moved in the radial direction by its own rotation. A substantially disc-shaped guide plate 23 to be displaced to the front, a metal annular wall 25 fixed to the front end of the guide plate 23 by a bolt 24, and an annular shape between the annular wall 25 and the guide plate 23 The guide plate 23 is attached to the other rotational direction (the direction opposite to the rotational direction of the timing sprocket 3) by applying a magnetic force to the spiral wall 26 that is radially expandable and contractable in the gap C and the annular wall 25. And an electromagnet 28 for energizing.

  As shown in FIGS. 1 and 4, the guide plate 23 has a cylindrical support portion 12b integrally extending forward of the cylindrical base portion 12a of the lever portion 12 and is inserted through the central insertion hole 23a with a predetermined clearance. In addition, the cylindrical portion 23b projecting from the other end surface and a ball bearing 29 provided on the outer periphery of the cylindrical support portion 12b are rotatably supported, and the three spiral guide grooves are formed on one end surface thereof. 30, 30, and 30 are formed. Further, the guide plate 23 is positioned in the axial direction by the ring member 31 screwed to the outer periphery of the distal end portion of the cylindrical support portion 12b pressing the inner race of the ball bearing 29 in the axial direction.

  Each spiral guide groove 30 is formed in a spiral shape in the same direction from the outer end portion 30a provided at a position of about 120 degrees in the circumferential direction of the guide plate 23 toward the center direction. Are arranged in the vicinity of the insertion hole 23a at the center of the guide plate 23, and are set to the same length. The spiral guide grooves 30 are arranged close to the inner and outer peripheries, and adjacent ones of the spiral guide grooves 30 are located between the inner and outer end portions 30a and 30b. , 30b are located. Further, the curvature of each spiral guide groove 30 is arbitrarily set, and in this embodiment, a uniform curvature is set from the outer end 30a to the inner end 30b. Further, each of the inner and outer end portions 30a, 30b has a bottom surface 30c. 30d is formed in a taper shape so as to gradually increase from the bottom surface on the center side toward each edge side, thereby exhibiting a stopper function.

  Accordingly, when the guide plate 23 rotates in the opposite direction to the timing sprocket 3 with the first guide ball 20 of each movable operation member 14 engaged with the spiral guide groove 30, each movable operation member 14 is then guided to the guide plate. Each of the spiral guide grooves 30 is configured to move radially inward along the spiral shape of each of the spiral guide grooves 30.

  As shown in FIG. 1, the spiral spring 26 has one end portion 26 a fixed to a part of the cylindrical portion 23 b of the guide plate 23, while the other end portion 26 b is axially extended from the outer peripheral side of the timing sprocket 3. The bolt 31 is fixed to the locking member 32 fixed to the bolt 31.

  The electromagnet 28 is attached to the VTC cover 6 so as to face the outer end face of the annular wall 25 in the axial direction and is turned on by being turned on or off by a control signal from the controller 7. Excited. The controller 7 detects the current engine operating state based on the engine speed by a crank angle sensor, the engine load by an air flow meter, and information signals from various sensors such as a water temperature sensor and a throttle valve opening sensor. It is like that.

  Hereinafter, the operation of the present embodiment will be described. First, at the time of engine start and idling operation, the energization of the electromagnet 28 is turned off by a control signal from the controller 7, and as a result, the guide plate 23 is a spring of the spiral spring 26. It is urged in the same direction as the rotation of the timing sprocket 3 only by the force. As a result, the guide plate 23 is maintained at the initial position by the guide balls 20 of the movable operation member 14 being in pressure contact with the outer end portions 30a of the spiral guide grooves 30 and further rotation is restricted. . Accordingly, each movable operation member 14 is displaced to the maximum in the radial direction as shown in FIGS. 1 and 2, and the cam connected to each movable operation member 14 via the link arm 15 and the lever member 12. The shaft 1 is maintained at the most retarded angle with respect to the timing sprocket 3.

  Therefore, at this time, the rotational phase of the crankshaft and the camshaft 1 is controlled to the most retarded angle side, and the engine rotation can be stabilized and the fuel consumption can be improved.

  When the engine shifts to normal operation, the electromagnet 28 is turned on by a control signal from the controller 7, and a magnetic force is applied from the electromagnet 28 so as to impart rotational resistance to the guide plate 23. Accordingly, the rotation of the guide plate 23 that follows and rotates with the timing sprocket 3 via the spiral spring 26 is prevented, and the guide plate 23 resists the spring force of the spiral spring 26 and rotates in the direction opposite to the rotation of the timing sprocket 3. The guide balls 20 of the movable operation members 14 are pressed against the inner end portions 30b of the spiral guide grooves 30 and controlled relative to the timing sprocket 3 under the urging force.

  At this time, in each movable operation member 14, each said first guide ball 20 rolls along the groove surface of each spiral guide groove 30, and each second guide ball 21 on the opposite side has both sliding grooves 11a, It moves straight inward in the radial direction along 11b and 11c. Then, when the connecting point (each pin 18) on the proximal end side of the link arm 15 moves radially inward along with the movement of each movable operation member 14 in the radially inner direction, the distal end side of the link arm 15 follows it. At this time, since the base end side of the link arm 15 is connected to each arm portion 13 of the lever member 12 by the pin 18, the link arm 15 moves in an arc shape while rotating the lever member 12. As a result, the assembly angle between the timing sprocket 3 and the camshaft 1 is adjusted and changed to the most advanced state.

  Therefore, at this time, the rotational phase of the crankshaft and the camshaft 1 is controlled to the most advanced angle side, and the engine output can be increased.

  The control of the rotation phase of the crankshaft and the camshaft 1 is not limited to switching between the two positions of the retard side and the advance side, but is continuously controlled to an arbitrary rotation phase by appropriately adjusting the magnetic force generated by the electromagnet 28. It is also possible to do.

  Further, as described above, the movable operation member 14 is displaced in the radial direction of the timing sprocket 3 along the sliding grooves 11a, 11b, and 11c, and the radial displacement of the movable operation member 14 is linked to the link arm 15 as well. Since the timing sprocket 3 and the camshaft 1 are converted to relative rotation via a link mechanism using the lever member 12, reliable phase control is performed with a compact structure that does not occupy a large space in the axial direction. be able to.

  The radial operation of each movable operation member 14 is also performed by engaging each spiral guide groove 30 of the guide plate 23 with the first guide ball 20 of the movable operation member 14. The mechanism does not greatly increase the space occupied in the axial direction.

  In the case of this device, the spiral spring 26 is employed as a spring member for connecting the timing sprocket 3 and the guide plate 23, and the spiral spring 26 is disposed between the guide plate 23 and the annular wall 25. The spring member does not increase the axial length of the device.

  Therefore, the axial length of the entire apparatus including the electromagnet 28 is greatly reduced as compared with the conventional one, and the mountability of the engine to the vehicle is surely improved.

  In addition, in this apparatus, the spiral guide groove 30 of the guide plate 23 and the first guide ball 20 of the movable operation member 14 are engaged with each other so that the rotation of the guide plate 23 is changed to the radial movement of the movable operation member 14. Therefore, if the curvature of the arc portion from the outer end portion 30a to the inner end portion 30b of the spiral guide groove 30 is set large, the relative rotation amount between the timing sprocket 3 and the camshaft 1 can be reduced. On the other hand, the relative rotational change can be increased. As a result, the outer diameter of the device can be made sufficiently small, and the overall size of the device can be reduced in combination with the reduction in the axial direction.

  Further, as described above, if the curvature of the arc portion from the outer end portion 30a to the inner end portion 30b of the spiral guide groove 30 is set to be large, the guide plate 23 is input by the load input from the movable operation member 14 side. The problem of rotating can be avoided. That is, for example, the trouble that the guide plate 23 rotates due to the fluctuation torque input to the camshaft 1 due to the spring force of the valve spring of the intake valve during engine operation does not occur, and the control of the valve timing is completed quickly. To do.

  Further, since the shape of each spiral guide groove 30 is set to be the same and one movable operation member 14 is provided for each spiral guide groove 30, the shape and size of the movable operation member 14 and the link are provided. The lengths of the arms 15 can all be the same. For this reason, each component can be shared, and thereby the manufacturing cost can be reduced.

  Furthermore, since the curvature of the arc portion of the spiral guide groove 30 can be arbitrarily set, for example, if the curvature is matched with the valve lift condition of the intake valve, the relative rotational speed between the timing sprocket 3 and the camshaft 1 Regardless of this, it is possible to increase the speed of the relative rotation phase conversion. As a result, the engine performance can be improved.

  Further, since the inner and outer end portions 30a and 30b of the spiral guide groove 30 function as stoppers that restrict the maximum rotation of the guide plate 23, it is not necessary to provide a separate stopper mechanism. As a result, an increase in the number of parts is suppressed, and an improvement in manufacturing work efficiency and an increase in cost can be suppressed.

  In addition, since the bottom surfaces 30c and 30d of the inner and outer end portions 30a and 30b are formed in a taper shape, a damper effect due to frictional resistance with the first guide ball 20 in the rotation end region of the guide plate 23 is exhibited and a rapid rotation is achieved. A dynamic stopping action is avoided, and a smooth stopping action is obtained. Further, since all of the inner and outer end portions 30a, 30b are formed in a tapered shape, the load at the time of stopping received from each first guide ball 20 is dispersed, and from this point, a smooth stopping action is further promoted. it can.

  Further, if the curvature of each of the inner and outer end portions 30a and 30b is set to a curvature that is substantially equal to the outer peripheral edge of the guide plate 23, for example, if the curvature is partially set to be large, a stable stopper function can be exhibited. .

  Furthermore, since this apparatus controls the rotation of the guide plate 23 relative to the timing sprocket 3 by the spring force of the spiral spring 26 and the magnetic force of the electromagnet 28, it is compared with the case where control is performed using the oil pressure of the oil pump. Thus, it is not necessary to be affected by the engine operating speed. Therefore, the valve timing control can be completed quickly regardless of the operating state of the engine. In addition, since the spring force of the spiral spring 26 is set in a direction to control the valve timing to the retard side, the engine start is guaranteed even if the electromagnet 28 breaks down.

  Further, the number of movable operation members 14 provided is arbitrary as long as it is two or more. However, if a plurality of movable operation members 14 are provided as in this embodiment, the stress applied to one movable operation member 14 is reduced, and the durability of the apparatus is increased. Improves.

  Further, the present invention is not limited to the configuration of the above-described embodiment. For example, the spiral guide groove 30 can be further increased, and its curvature can be changed in the middle. In this way, by changing the curvature in the middle, the operation of the movable operation member 14 can be stably maintained at this change position. For example, if the curvature is changed in accordance with a steady operation region such as a load during engine rotation. Thus, stable control of the valve timing at this point becomes possible.

  Further, the rotation urging means of the guide plate 23 can be constituted by, for example, another electromagnet instead of the spiral spring 26.

Sectional drawing which follows the AA line of FIG. 2 which shows embodiment of this invention. Sectional drawing which follows the BB line of FIG. 1 which shows the same embodiment. Sectional drawing which follows the CC line | wire of FIG. Sectional drawing which follows the DD line | wire of FIG. Sectional drawing which follows the EE line | wire of FIG.

Explanation of symbols

1 ... Camshaft (driven rotor)
3. Timing sprocket (drive rotor)
4 ... Assembly angle adjusting mechanisms 11a, 11b, 11c ... Sliding grooves (radial direction guide portions)
14 ... Moving operation member 15 ... Link arm (link)
20, 21 ... Guide ball 23 ... Guide plate 26 ... Spiral spring (spring member)
28 ... Electromagnet 30 ... Spiral guide groove

Claims (1)

A drive rotor that is driven to rotate by the crankshaft of the engine;
A driven rotating body provided coaxially with the driving rotating body so as to be relatively rotatable,
A guide plate having a spiral guide groove with a partially increased curvature at the end;
The guide is configured to engage with the spiral guide groove and be guided in the radial direction by the drive rotator, and by rotating the guide plate with respect to the drive rotator and the driven rotator, the guide A movable operation member provided to move in the radial direction of the plate;
An arm portion provided in the driven rotating body and extending in a radial direction;
A link arm that connects the arm portion and the movable operation member, and makes the relative rotation phase of the drive rotating body and the driven rotation body variable by moving the movable operation member in the radial direction;
A valve timing control apparatus for an internal combustion engine, comprising:

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