JP2019152109A - Dynamic valve device of internal combustion engine - Google Patents

Abstract

To make an energization force imparted to an intake/exhaust valve variable in response to a rotation number of an internal combustion engine by a simple mechanism.SOLUTION: A dynamic valve device 10 comprises: a locker arm 12 for driving an intake/exhaust valve 11; a torsion spring 13 for imparting an energization force in a direction for closing the intake/exhaust valve 11 to the locker arm 12; and an energization force variable mechanism 14 for increasing the energization force of the torsion spring 13 accompanied by an increase of a rotation number of a drive shaft of an internal combustion engine.The energization force variable mechanism 14 has an input shaft 22 whose rotation number is increased and decreased in conjunction with the rotation number of the drive shaft, an internal peripheral member 23 whose an N-pole and an S-pole are alternately magnetized along a rotation direction, and an external peripheral member 24 which corotates together with the internal peripheral member 23, and is composed of a magnetic material for receiving a rotation force. One end of the torsion spring 13 is arranged at the external peripheral member 24 side, the other end of the torsion spring is arranged at the locker arm 12 side, and the torsion of the torsion spring 13 is increased by the rotation of the external peripheral member 24 accompanied by the increase of the rotation number of the drive shaft.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a valve gear that drives intake and exhaust valves of an internal combustion engine for a vehicle.

  As a valve operating device for driving an intake / exhaust valve of an internal combustion engine, the intake / exhaust valve is lifted by a cam rotating around a rotation axis together with a camshaft, while a biasing force of a valve spring provided coaxially with the intake / exhaust valve is used. A configuration for closing the intake / exhaust valve is generally known.

  In this valve operating apparatus, when the internal combustion engine is rotating at a low speed, the valve operation is also relatively slow, so that the valve operation can follow the rotation of the internal combustion engine even if the urging force of the valve spring is not so large. On the other hand, when the internal combustion engine is at a high speed, if the urging force of the valve spring is insufficient, the valve operation cannot follow the rotation of the internal combustion engine, causing problems such as bounce, jump, surging, etc. There is a fear. Therefore, in general, a valve spring having a sufficient urging force suitable for the high rotation range is often used so as to avoid the above-described problem in the high rotation range.

  In this case, problems such as bounce at high revolutions can be avoided, but problems such as an increase in friction occur due to excessive biasing force of the valve spring at low revolutions. It is possible to reduce the urging force by reducing the amount of contraction of the valve spring at the time of low rotation, but in order to make the amount of contraction (cam lift amount) variable, the structure of the valve operating device is significantly changed. It is necessary and is not the best method in terms of cost.

  As other mechanisms for making the urging force acting on the intake / exhaust valve variable according to the rotational speed of the internal combustion engine, for example, configurations shown in Patent Documents 1 to 4 below have been proposed.

  In the configuration according to Patent Document 1, the oil pump is driven by the internal combustion engine, and the spring load of the torsion spring acting on the intake / exhaust valve is increased as the rotational speed of the internal combustion engine increases (Patent Document 1). (Refer to the fifth page, the twelfth line to the sixth page, the sixth line, FIG. 1, etc.).

  In the configuration according to Patent Document 2, hydraulic pressure is introduced into the hydraulic chamber by a lubricating oil pump that is rotationally driven by an internal combustion engine. This hydraulic pressure drives a piston that functions as a spring seat for applying a spring load to the intake / exhaust valve, and increases the spring load of the spring acting on the intake / exhaust valve as the rotational speed of the internal combustion engine increases. (Refer to Patent Document 2 on page 1, lower right column, line 18 to page 2, lower left column, line 13; drawing, etc.).

  In the configuration according to Patent Document 3, a permanent magnet attached to one end of the intake / exhaust valve along the biasing direction of the spring means and a spring means for biasing the intake / exhaust valve are attached to the other end. Auxiliary spring means having an electromagnet is also provided. By changing the polarity and magnitude of the current applied to the electromagnet of the auxiliary spring means, the lift load of the intake / exhaust valve is variable (see page 2, right upper column, ninth line to lower left column, fifth line of Patent Document 3). , See FIG.

  In the configuration according to Patent Document 4, a permanent magnet spring receiver that receives the valve spring is provided in a lift space in which a part of the valve spring is accommodated, and an electromagnet is provided to face the spring receiver. . The electromagnet is energized, and the spring receiver is pushed up by the repulsive force generated between the spring receiver and the electromagnet to adjust the urging force of the valve spring (paragraphs 0020 to 0025 in FIG. 1, FIG. 1 and the like). reference).

Japanese Utility Model Publication No. 61-48908 JP-A-57-13207 JP-A-2-221608 Japanese Patent Laid-Open No. 11-50822

  In the hydraulic configurations shown in Patent Documents 1 and 2, the hydraulic pressure supplied from the pump basically increases with the rotational speed of the internal combustion engine, but this pump is operated at high speed (particularly 3000 rpm or more). Many pumps have a pump characteristic in which the increase in hydraulic pressure with respect to the increase in rotational speed is slow (or peaked). In this case, there is a possibility that a necessary and sufficient urging force for the intake / exhaust valve cannot be ensured at the time of high rotation at which problems such as bounce become significant. Although it is conceivable to provide a dedicated hydraulic pump independent of the internal combustion engine, the apparatus configuration becomes complicated, and it is necessary to separately provide an output control device for the pump.

  Moreover, in the electromagnet type structure shown in Patent Documents 3 and 4, it is necessary to separately provide a current control device for controlling the current supplied to the electromagnet, and there is a problem that the cost becomes high as in the case of the hydraulic type. .

  Therefore, an object of the present invention is to vary the urging force applied to the intake and exhaust valves in accordance with the rotational speed of the internal combustion engine with a simple mechanism.

  In order to solve the above-mentioned problems, in the present invention, the camshaft is swung around the swinging shaft by contact with the cam rotating around the rotating shaft, and the intake / exhaust valve of the internal combustion engine is moved in the axial direction. A rocker arm to be driven, a torsion spring that applies an urging force to the rocker arm in a direction to close the intake / exhaust valve, and the urging force of the torsion spring as the rotational speed of the drive shaft of the internal combustion engine increases. An urging force variable mechanism that increases, and the urging force variable mechanism rotates around the axis integrally with the input shaft, the input shaft increasing and decreasing in association with the rotational speed of the drive shaft, An inner peripheral member made of a magnet in which N poles and S poles are alternately magnetized along the rotation direction; and provided coaxially with the inner peripheral member and spaced apart in the radial direction so as to be rotatable about an axis. Axis of peripheral member An outer peripheral member made of a magnetic material that receives a rotational force in the direction of being rotated along with the rotation of the roller, one end of the torsion spring on the outer peripheral member side, and the other end opposite to the one end A valve operating apparatus for an internal combustion engine, which is provided on each side of the rocker arm and in which torsion of the torsion spring is strengthened by the rotation of the outer peripheral member as the rotational speed of the drive shaft increases, is configured.

  In the above configuration, it is preferable that the outer peripheral member is a magnet in which N and S poles are alternately magnetized along the rotation direction.

  In each configuration, the inner circumferential member is composed of an assembly of a plurality of divided magnets divided along the rotation direction thereof, and the centrifugal force accompanying the rotation around the axis of the inner circumferential member causes the It is preferable that each divided magnet is individually movable radially outward.

  In the case where the inner peripheral member is constituted by divided magnets, a configuration is provided in which an isolation member is disposed between the adjacent divided magnets to isolate the divided magnets in a state where the centrifugal force is not acting. Is preferable.

  In the present invention, the urging force applied from the torsion spring to the rocker arm is continuously variable according to the increase / decrease in the rotational speed of the internal combustion engine by the urging force variable mechanism. As a result, the intake / exhaust valve can be made to follow the rotation of the internal combustion engine reliably at the time of high rotation, and problems such as bounce can be surely prevented. The occurrence of friction can be suppressed by preventing the biasing force from acting. Moreover, this biasing force variable mechanism is mechanically operated only by the input from the input shaft linked with the rotational speed of the drive shaft of the internal combustion engine, and does not require a special control device. It can be ensured and the cost can be reduced.

The front view which shows one Embodiment of the valve operating apparatus of the internal combustion engine which concerns on this invention The perspective view of the principal part of the valve operating apparatus shown in FIG. Sectional drawing which shows the other example of the principal part shown in FIG. Sectional drawing of the principal part of the valve operating apparatus shown in FIG. The perspective view which notched a part of principal part shown in FIG. 4A and 4B are cross-sectional views of the main part shown in FIG. 4, where FIG. Sectional drawing which follows the VII-VII line in Fig.6 (a) Sectional drawing which shows the other example of sectional drawing shown in FIG. Sectional drawing of the other example of the principal part shown in FIG. 6 is shown, (a) at the time of low rotation (or at the time of a stop), (b) at the time of high rotation

  An embodiment of a valve gear 10 (hereinafter referred to as a valve gear 10) of an internal combustion engine (hereinafter referred to as an engine) according to the present invention will be described with reference to FIG. This valve operating device 10 is a device for driving an intake / exhaust valve 11 (intake valve or exhaust valve) of a vehicle engine, and mainly includes a rocker arm 12, a torsion spring 13, and a biasing force variable mechanism 14. As a component.

  The rocker arm 12 swings around the swinging shaft 12a by abutment with a cam shaft (not shown) and a cam 15 rotating around the rotation shaft, and drives the intake / exhaust valve 11 of the engine in the axial direction. It has a function. The rocker arm 12 is a swing arm type having a fulcrum (swing shaft 12a), a force point (contact portion with the cam 15), and an action point (engagement portion of the intake / exhaust valve 11) in this order along the longitudinal direction. is there. The swing shaft 12 a is supported by a lash adjuster 16.

  A through hole reaching the intake / exhaust port 18 is formed in the cylinder head 17 of the engine, and a valve guide 19 is fitted into the through hole. A valve stem 11 a of the intake / exhaust valve 11 that opens and closes the intake / exhaust port 18 is inserted through the valve guide 19. As shown in FIG. 2, a recess is formed in the valve stem end 11b at the end of the valve stem 11a (the upper end in FIG. 1), and a rocker arm 12 (with a tip branched in a fork shape) is formed in this recess. The action point) is engaged. Thus, instead of engaging the rocker arm 12 and the valve stem end 11b, the rocker arm 12 and the valve stem end 11b may be coupled via the ball joint 20, as shown in FIG.

  The intake / exhaust valve 11 is driven by a rocker arm 12 in either direction of opening and closing. For this reason, in a general valve operating apparatus, a valve spring that is arranged coaxially with the intake / exhaust valve and urges the intake / exhaust valve in a closing direction is not provided. As a result, the intake / exhaust valve 11 used in the valve gear 10 according to the present invention can be shortened by a length corresponding to the axial length of a general valve spring, thereby reducing the size and weight of the engine. And cost reduction by reducing the number of parts.

  The torsion spring 13 has a function of applying a biasing force in the direction of closing the intake / exhaust valve 11 to the rocker arm 12. One end of the torsion spring 13 is fixed near the power point of the rocker arm 12, and the other end opposite to the one end is fixed to a shaft 21 described later of the biasing force variable mechanism 14. The torsion spring 13 has a significantly higher resonance frequency than a coil spring employed in a general valve gear. For this reason, there is no possibility that resonance will occur when the urging force of the torsion spring 13 is continuously changed in accordance with the engine speed.

  The attachment position of the torsion spring 13 to the rocker arm 12 shown in FIG. 1 is an example, and the attachment position is appropriately changed as long as a predetermined urging force can be applied to the intake / exhaust valve 11 by the torsion spring 13. (For example, in the vicinity of the action point).

  The urging force variable mechanism 14 has a function of increasing the urging force of the torsion spring 13 as the rotational speed of the engine drive shaft (not shown) increases. As shown in FIG. 4, the biasing force variable mechanism 14 includes an input shaft 22, an inner peripheral member 23, and an outer peripheral member 24.

  The input shaft 22 is connected to the drive shaft of the engine via a gear (not shown), and the rotational speed increases or decreases in conjunction with the rotational speed of the drive shaft. That is, when the rotational speed of the drive shaft increases, the rotational speed of the input shaft 22 also increases, and when the rotational speed of the drive shaft decreases, the rotational speed of the input shaft 22 also decreases. The gear ratio between the drive shaft and the input shaft 22 is basically constant, but is variable according to the rotational speed of the drive shaft, for example, the gear ratio increases as the rotational speed of the drive shaft increases. And it can also be set as the structure which rotates the input shaft 22 at higher speed.

  The inner peripheral member 23 is a member that rotates around the axis integrally with the input shaft 22. As shown in FIGS. 5 and 6A, the inner peripheral member 23 is composed of a plurality of divided magnets 23a (permanent magnets) divided along the rotation direction and having a central angle of 45 degrees. . As shown in FIG. 6A and FIG. 7, each divided magnet 23a has two types, an outer diameter side having an N pole and an inner diameter side having an S pole, and an outer diameter side having an S pole and an inner diameter side having an N pole. These constitute an assembly in which they are alternately arranged in an annular shape. That is, the N pole and the S pole are alternately magnetized on the outer peripheral portion of the inner peripheral member 23 along the rotation direction. In addition, the magnitude | size of this center angle is an illustration, Comprising: It can change suitably (for example, 30 degree | times etc.).

  The inner peripheral member 23 is housed in a cup-shaped yoke 25 having a flat circular bottom surface that rotates about the axis together with the input shaft 22. In the configuration shown in FIG. 4, the input shaft 22 rotates counterclockwise (in the direction of the arrow r1 in FIG. 4) when viewed from the shaft 21 side. On the bottom surface of the yoke 25, the same number of guide grooves 25a as the number of divided magnets 23a are formed radially from the center. In addition, a guide protrusion 23b that is guided in the radial direction by the guide groove 25a is formed on the back surface (the surface facing the bottom surface of the yoke 25) of each divided magnet 23a.

  When the inner peripheral member 23 (that is, the input shaft 22) is rotated at a low speed or stopped, the divided magnets 23a are integrated with each other as shown in FIG. 6A. At this time, the guide protrusion 23b is located at the inner diameter side end of the guide groove 25a. On the other hand, at the time of high rotation of the inner peripheral member 23, as shown in FIG. 6 (b), centrifugal force acts on each divided magnet 23a, and each divided magnet 23a has an individual diameter against the magnetic force. Move outward in the direction. Each divided magnet 23a is restricted from moving further outward in the radial direction when the guide protrusion 23b reaches the outer diameter side end of the guide groove 25a. Thereby, each divided magnet 23a and the outer peripheral member 24 are prevented from coming into direct contact.

  In this embodiment, as shown in FIG. 7, each divided magnet 23 a is opposite to one of the N or S poles on the radially outer side and the one of the N or S poles on the radially inner side. Although the magnet in which the other pole is formed is adopted, as shown in FIG. 8, the one pole of the N pole or S pole on the surface of each divided magnet 23a and the one pole of the N pole or S pole on the back surface In some cases, a magnet on which the other opposite pole is formed can be adopted.

  As shown in FIGS. 4, 5, and 6 (a), the outer peripheral member 24 is coaxially spaced from the inner peripheral member 23 and is provided to be rotatable around an axis. The outer peripheral member 24 is a permanent magnet in which N poles and S poles are alternately formed along the rotation direction. In addition, it can also comprise from a magnetic material (ferromagnetic substance) instead of a permanent magnet. The outer peripheral member 24 is provided with a shaft 21 that rotates around the axis integrally with the outer peripheral member 24 so as to protrude in the axial direction. As described above, the other end of the torsion spring 13 is fixed to the shaft 21. In some cases, the other end of the torsion spring 13 can be directly fixed to the outer peripheral member 24 without providing the shaft 21 to the outer peripheral member 24 by making the outer peripheral member 24 into a shape suitable for winding the torsion spring 13.

  When the inner circumferential member 23 rotates about the axis together with the input shaft 22 (see arrow r1 in FIG. 4), the inner circumferential member 24 is caused to interact with the outer circumferential member 24 by the interaction of the magnetic force between the inner circumferential member 23 and the outer circumferential member 24. Rotational force in the direction rotated by 23 (see arrow r2 in FIG. 4) acts. Then, the outer circumferential member 24 rotates until the rotational force acting on the outer circumferential member 24 and the biasing force by the torsion spring 13 are balanced. With this rotation, the torsion spring 13 is torsionally increased, and the biasing force applied to the rocker arm 12 is increased.

  The rotation angle of the outer peripheral member 24 continuously increases as the rotation of the drive shaft (inner peripheral member 23) of the engine increases. That is, the urging force of the torsion spring 13 can be made continuously variable according to the engine speed. In order to ensure an appropriate urging force by the torsion spring 13, the maximum rotation angle of the outer peripheral member 24 at the time of high rotation can be set to several tens of degrees, for example.

  Further, when the rotation of the inner peripheral member 23 becomes a high rotation, as described above, the respective divided magnets 23a constituting the inner peripheral member 23 move radially outward by the centrifugal force. By this movement, the outer peripheral member 24 composed of each divided magnet 23a and a permanent magnet approaches. Since the magnitude of the magnetic force acting between the magnets is inversely proportional to the square of the distance between them, the magnetic force acting between the magnets abruptly increases with the proximity of each divided magnet 23a and the outer peripheral member 24. A sufficient biasing force by the torsion spring 13 can be ensured at the time of high rotation.

  In the biasing force variable mechanism 14 employed in the present invention, as shown in FIGS. 9 (a) and 9 (b), a split magnet is interposed between adjacent split magnets 23a when centrifugal force is not acting. It can also be set as the structure which has arrange | positioned the isolation | separation member 26 which isolates 23a. By separating the adjacent divided magnets 23a by the thickness of the separating member 26, the attractive force between the adjacent divided magnets 23a can be weakened. In this way, when a centrifugal force acts on the divided magnets 23a as the inner peripheral member 23 rotates, the divided magnets 23a can be smoothly moved radially outward, and changes in engine speed can be achieved. In response to the above, the urging force applied to the intake / exhaust valve 11 can be changed smoothly and continuously.

  In this embodiment, resin is used as the material of the separating member 26, but other materials can be used as long as the attractive force between the divided magnets 23a can be appropriately weakened.

  According to the valve operating apparatus 10 described above, the engine speed can be controlled only by a simple mechanical configuration without using a special control apparatus for controlling the hydraulic pressure or the magnetic force of the electromagnet as described in the background art. Correspondingly, the urging force applied to the intake / exhaust valve 11 can be made continuously variable. For this reason, it is possible to ensure a good operating state of the valve gear 10 in the entire rotation region while reducing the cost.

  If this valve operating apparatus 10 is a 4-cycle engine provided with the hydraulic intake / exhaust valve clearance adjustment mechanism, it can be employed regardless of the combustion type, cylinder arrangement, and number of cylinders. In addition, since there are many parts in common with the existing valve operating apparatus, the existing valve operating apparatus can be easily replaced with the valve operating apparatus 10 according to the present invention.

  The above embodiment is merely an example in any point, and solves the problem of the present invention that the urging force applied to the intake / exhaust valve can be varied in accordance with the rotational speed of the internal combustion engine with a simple mechanism. As long as it is possible, the adopted components can be appropriately changed.

  For example, in the above-described embodiment, the configuration in which the divided magnet 23a divided in the circumferential direction is employed as the inner circumferential member 23 is shown, but a configuration in which an integral donut-shaped magnet is employed may be employed.

DESCRIPTION OF SYMBOLS 10 Valve apparatus 11 Intake / exhaust valve 11a Valve stem 11b Valve stem end 12 Rocker arm 12a Oscillating shaft 13 Torsion spring 14 Energizing force variable mechanism 15 Cam 16 Rush adjuster 17 Cylinder head 18 Intake / exhaust port 19 Valve guide 20 Ball joint 21 Shaft 22 Input shaft 23 Inner peripheral member 23a Split magnet 23b Guide projection 24 Outer peripheral member 25 Yoke 25a Guide groove 26 Isolation member

Claims (4)

A rocker arm that swings around a swing shaft by abutting a cam shaft and a cam that rotates around a rotation shaft, and drives an intake / exhaust valve of the internal combustion engine in its axial direction;
A torsion spring that applies an urging force in a direction to close the intake and exhaust valves to the rocker arm;
An urging force variable mechanism that increases the urging force of the torsion spring as the rotational speed of the drive shaft of the internal combustion engine increases;
With
The biasing force variable mechanism is
An input shaft whose rotational speed increases or decreases in conjunction with the rotational speed of the drive shaft;
An inner peripheral member made of a magnet that rotates around the shaft integrally with the input shaft, and in which N and S poles are alternately magnetized along the rotation direction;
An outer periphery made of a magnetic material that is provided coaxially with the inner peripheral member and spaced apart in the radial direction so as to be rotatable about an axis, and that receives a rotational force in a direction rotated along with the rotation of the inner peripheral member around the axis. Members,
One end of the torsion spring is provided on the outer peripheral member side, and the other end opposite to the one end is provided on the rocker arm side, and the outer member of the outer peripheral member as the rotational speed of the drive shaft increases. A valve operating apparatus for an internal combustion engine in which the torsion spring is strengthened by rotation. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the outer peripheral member is a magnet in which N poles and S poles are alternately magnetized along a rotation direction thereof. The inner circumferential member is composed of an assembly of a plurality of divided magnets divided along the rotation direction, and each of the divided magnets is individually generated by centrifugal force accompanying rotation around the axis of the inner circumferential member. The valve gear for an internal combustion engine according to claim 1 or 2, which is movable radially outward. 4. The valve operating apparatus for an internal combustion engine according to claim 3, wherein a separating member is disposed between the divided magnets adjacent to each other in a state where the centrifugal force is not acting to separate the divided magnets from each other.

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