JP2005320887A - Valve train for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power loss, increase durability and facilitate adjustment of clearance with a cam when valve lift at the time of opening an intake valve 3 of an internal combustion engine by rotation of the cam 5 interlocking with a crank shaft. <P>SOLUTION: A fulcrum member 15 is abutted on one side surface of a rocking member 9. The abutment point is moved to one end part side or the other end part side of a rocking member. A roller body (cam abutment part) 10 provided on one end part in a side surface on the other side of the rolling member is abutted on the cam 5 to rock the rocking member in a right and left direction around the abutment part of the fulcrum member by rotation of the cam. A cam surface 19 opening and operating an intake valve while resisting a spring 4 by rocking rotation of the rocking member is provided on the other end part of the rocking member. The roller body (cam abutment part) on one end part of the rocking member is constructed adjustably to project and contract toward the cam. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a valve mechanism for opening at least one of the intake valve and the exhaust valve in a valve mechanism that opens and closes at least one of an intake valve and an exhaust valve in an internal combustion engine in conjunction with rotation of a crankshaft. The present invention relates to a valve mechanism that controls a lift amount and a working angle in accordance with an operating state of an internal combustion engine.

  In recent internal combustion engines, in order to improve fuel consumption and output, etc., the valve lift amount when opening the intake valve is small in the low load region of the internal combustion engine according to the operating state of the internal combustion engine. Control is performed so as to increase in a high load range.

Regarding this type of valve lift variable valve mechanism, Patent Document 1 as a prior art includes a valve cam rotating in conjunction with a crankshaft in FIGS. The swinging member is brought into contact with the substantially intermediate portion between the one end and the other end so that the swinging member swings with the one end serving as a fulcrum of the rotation center by rotation of the cam. The cam surface formed on the portion is contacted to the rocker arm with respect to the upper end of the intake valve so that the intake valve is opened against the spring by swinging the swing member, while one end portion of the swing member is According to the operating state of the internal combustion engine, the swinging angle by the cam of the swinging member is displaced so as to be small in a low load region or a low rotation region and large in a high load region or a high rotation region, The amount of valve lift in the intake valve Small load region, it is proposed to control so as to increase in the high load region.
JP-A-7-63023

  However, the valve mechanism in this prior art uses the cam surface of the other end portion of the swing member as an operating point for the intake valve, while the swing member has a substantially intermediate portion between the one end portion and the other end portion. Is used as a force point for contact with the cam, and the swinging member is swung by rotation of the cam with one end portion being a fulcrum of the rotation center to open the intake valve against the spring. Therefore, in the swing member, the action length from the fulcrum at one end to the action point on the intake valve is much larger than the force point from the fulcrum at one end to the force point where the cam contacts. It is structured to be very long.

  In other words, the operation length from the fulcrum to the action point is significantly longer than the force point length from the fulcrum to the force point. It is necessary to apply a much larger operating force at the cam according to the ratio of the force point length to the action length than the spring force that keeps the intake valve closed with respect to the force point, Since a large amount of power is required to rotate the cam, there is a problem that not only the power loss is quite large but also the durability is very low.

  It is a technical object of the present invention to solve these problems and to provide a valve operating device that can easily adjust and set the clearance for the cam or the clearance for the intake valve or the exhaust valve. It is.

In order to achieve this technical problem, claim 1 of the present invention provides:
“A cam that rotates in conjunction with a crankshaft and a swinging member. One of the left and right side surfaces in the longitudinal direction of the swinging member has one end in the longitudinal direction of the swinging member and the other. A fulcrum member is abutted against a portion between the ends, and the abutment point is configured to move to the one end side or the other end side. A cam contact portion is provided at the one end portion, and the cam contact portion is provided on the cam, and the swinging member swings and rotates in the left-right direction with the contact portion of the fulcrum member as a fulcrum by the rotation of the cam. The swinging member is provided with guide means for preventing the swinging member from moving in the longitudinal direction in a state in which the swinging rotation of the swinging member is allowed. At the other end of the moving member, the intake valve And a cam surface that opens and operates at least one of the exhaust valves against the spring, and the cam contact portion at one end of the swinging member can be adjusted to protrude and retract toward the cam. Configured. "
It is characterized by that.

Further, claim 2 of the present invention provides
“A cam that rotates in conjunction with a crankshaft and a swinging member. One of the left and right side surfaces in the longitudinal direction of the swinging member has one end in the longitudinal direction of the swinging member and the other. A fulcrum member is abutted against a portion between the ends, and the abutment point is configured to move to the one end side or the other end side. A cam contact portion is provided at the one end portion, and the cam contact portion is provided on the cam, and the swinging member swings and rotates in the left-right direction with the contact portion of the fulcrum member as a fulcrum by the rotation of the cam. The swinging member is provided with guide means for preventing the swinging member from moving in the longitudinal direction in a state in which the swinging rotation of the swinging member is allowed. At the other end of the moving member, the intake valve And a cam surface that opens and operates at least one of the exhaust valves against the spring, and means for moving and adjusting the swing member in the longitudinal direction is provided in the guide means. "
It is characterized by that.

Furthermore, claim 3 of the present invention provides
“A cam that rotates in conjunction with a crankshaft and a swinging member. One of the left and right side surfaces in the longitudinal direction of the swinging member has one end in the longitudinal direction of the swinging member and the other. A fulcrum member is brought into contact with a portion between the end portions, and the contact point is configured to move to the one end portion side or the other end portion side. A roller shaft is rotatably supported on a pin shaft so that the roller body rotates together with the pin shaft. The roller body is attached to the cam, and the swing member is brought into contact with the fulcrum member by rotation of the cam. The bushing body that is pivotally fitted to the pin shaft so as to be pivoted in the left-right direction is slidably fitted in the guide groove so that the pivoting member can be pivoted. To prevent the swinging member from moving in the longitudinal direction while allowing On the other hand, at the other end of the swing member, a cam surface is provided that opens and operates at least one of the intake valve and the exhaust valve against the spring by swinging rotation of the swing member. Furthermore, the roller body and the bush body were eccentric with respect to the pin shaft. "
It is characterized by that.

  In the above-described configuration, the swinging member swings and rotates with the contact point of the fulcrum member as the fulcrum of rotation by the rotation of the cam contact part at one end or the cam that the roller body contacts. At the cam surface at the other end of the swing member, the intake valve or the exhaust valve opens and operates against the spring.

  By moving the contact point of the fulcrum member, which is the fulcrum of the center of rotation of the rocking member, toward one end of the rocking member, the rocking angle of the rocking member is increased. The valve lift amount when the valve or the exhaust valve opens increases.

  Further, by moving the contact point of the fulcrum member with respect to the swing member toward the other end of the swing member, the swing angle of the swing member is reduced. The valve lift amount can be controlled during the operation of the internal combustion engine by the movement of the fulcrum member so that the valve lift amount when opening is small.

  The swinging member has a cam contact portion at one end as a force point, and a cam surface at the other end as an action point for the intake valve or the exhaust valve, and the fulcrum member is between these force points and the action points. The contacting portion is a fulcrum of the swing rotation center of the swing member, and the force point length from the force point to the fulcrum can be made closer to the action length from the action point to the fulcrum, so that In addition, it is possible to avoid that the power point length is significantly longer than the action length.

  As a result, the operating force by the cam, and hence the power required to rotate the cam, can be reliably reduced, so that power loss can be reduced and durability can be greatly improved.

  In this case, as described in claim 1, the cam contact portion at one end portion of the swing member is configured to be adjustable so as to protrude and retract toward the cam, so that the swing member, the cam, The clearance between the cam contacts can be accurately adjusted quickly and easily without the need for disassembly by adjusting the appearance of the cam contact portion with respect to the cam.

  According to a second aspect of the present invention, the guide means is provided with means for adjusting the movement of the swinging member in the longitudinal direction thereof, so that the swinging member and the intake valve or the exhaust valve can be connected to each other. The clearance between the cam contacts can be adjusted easily and promptly without the need for disassembly by adjusting the appearance of the cam contact portion with respect to the cam.

  Furthermore, by adopting the configuration described in claim 3, the roller body can be adjusted to move toward and away from the cam by the rotation of the pin shaft relative to the swing member, and the bushing body can be rotated relative to the pin shaft. Since the swing member can be moved and adjusted in the longitudinal direction, a clearance is set between the swing member and the cam, and a clearance is set between the swing member and the intake valve or the exhaust valve. Can be achieved very easily and quickly without the need for total disassembly.

  Hereinafter, the drawings of FIGS. 1 to 6 showing a case where the embodiment of the present invention is applied to an intake valve will be described.

  In this figure, reference numeral 1 denotes a cylinder head in an internal combustion engine. The cylinder head 1 is provided with an intake port 2 into a cylinder (not shown), and an opening of the intake port 2 into the cylinder includes An intake valve 3 that is normally closed by a spring 4 is provided.

  A cam shaft 6 having a cam 5 for opening and closing the intake valve 3 is pivotally supported on the cylinder head 1 so as to rotate in conjunction with a crankshaft (not shown) in the internal combustion engine. .

  The top end of the intake valve 3 is in contact with the tip end of a rocker arm 8 whose base end is pivotally attached to the cylinder head 1 side by a bolt 7 screwed.

  Reference numeral 9 denotes a rocking member, and this rocking member 9 is disposed between the cam 5 and the rocker arm 8 so that the longitudinal direction is long, and the upper end of the rocking member 9 in the longitudinal direction. A pin shaft 11 is rotatably supported by the portion. A roller body 10 serving as a cam contact portion that contacts the cam 5 rotates together with the pin shaft 11. Are provided integrally.

  The swing member 9 is positioned between a pair of left and right bracket bodies 12 provided integrally with the cylinder head 1 so as to prevent movement in the axial direction of the pin shaft 11. ing.

  Further, the swing member 9 is slidable in a guide groove 14 provided so that a bush body 13 fitted to both ends of the pin shaft 11 at an upper end portion thereof extends laterally in the pair of bracket bodies 12. By being fitted to the cam 5, the swinging member 9 is prevented from moving in the longitudinal direction while being able to freely reciprocate in the radial direction with respect to the cam 5.

  On the other hand, on the cylinder head 1 side, the base end of the fulcrum member 15 is pivotally supported by the pin shaft 16, and the distal end of the fulcrum member 15 is on both the left and right sides in the longitudinal direction of the swing member 9. Of the swinging member 9 is movably contacted with one longitudinal side surface opposite to the cam 5 while the roller body 10 at the upper end of the swinging member 9 is By pressing and urging the cam 5 with a return spring 17 provided between the lower end of the swing member 9 and the cylinder head 1, the swing member 9 is rotated by the rotation of the cam 5. The position where the tip of the fulcrum member 15 contacts is configured to swing and rotate in the left-right direction with a fulcrum at the center of rotation.

  By providing a cam surface 19 in contact with a roller 18 rotatably provided on the rocker arm 8 at the lower end of the rocking member 9, the rocking member 9 swings the rocker arm 8 via the rocker arm 8. The intake valve 3 is configured to open and act against the spring 4.

  In addition to the configuration described above, the fulcrum member 15 is moved from the middle load range indicated by the solid line when the load is low by an actuator (not shown) that operates according to the load in the internal combustion engine. 9 is configured to move to the lower end side of the swinging member 9 from the middle load range indicated by the solid line when the load is high.

  In this case, a portion of one side surface of the swinging member 9 where the tip of the fulcrum member 15 contacts is formed on an arcuate surface 9a having a radius R centering on the rotation center of the fulcrum member 15, and The radius R of the arcuate surface 9a is approximately equal to the distance from the straight line 9b connecting the center of the pin shaft 11 at the upper end of the rocking member 9 and the center of the roller 18 in the rocker arm 8 to the rotation center of the fulcrum member 15. By equalizing, the oscillating member 9 is moved in a state where the fulcrum member 15 is moved to the upper end side of the oscillating member 9 and in a state where the fulcrum member 15 is moved to the lower end side of the oscillating member 9. The configuration is such that there is little displacement in the lateral direction.

  Of the one side surface of the oscillating member 9, the portion where the tip of the fulcrum member 15 contacts is a plane parallel to the straight line 9b instead of the arc surface 9a as described above. The fulcrum member 15 may be configured to move in a direction parallel to the straight line 9b, so that the swinging member 9 is less likely to be displaced in the lateral direction.

  Then, as shown in FIG. 3, the roller body 10 at the upper end portion of the swing member 9 is eccentric with respect to the pin shaft 11 by an appropriate dimension e1, so that the roller shaft 10 is rotated by the rotation of the pin shaft 11. The body 10 is configured so that it can be adjusted toward and away from the cam 5.

  In this case, a slit groove 19 is provided in a portion of the upper end portion of the swinging member 9 where the pin shaft 11 is fitted, and by tightening bolts 22 on both sides 20 and 21 sandwiching the slit groove 19. The pin shaft 11 can be fixed at an arbitrary rotational position so as not to rotate. In other words, the roller body 10 can be fixed at an arbitrary protruding position relative to the cam 5 so as not to be protruded and retracted. ing.

  Further, as shown in FIG. 4, the bush body 13 slidably fitted in the guide groove 14 of the bracket member 12 is appropriately dimensioned e2 with respect to the pin shaft 11 on which the bush body 13 is fitted. By only decentering, the rocking member 9 can be moved and adjusted in the vertical direction by the rotation of the bush body 13.

  In this case, the bush body 13 is provided with a slit groove 23 and the parts 24 and 25 on both sides sandwiching the slit groove 23 are tightened with bolts 26 to rotate the bush body 13 at an arbitrary rotational position. In other words, it is configured so that it can be fixed in an immovable state at an arbitrary movement position in the swing member 9 due to the rotation of the bush body 13 so that it can be fixed impossible.

  In this configuration, the swinging member 9 swings and swings in the left-right direction with the position where the tip of the fulcrum member 15 contacts as a fulcrum of the rotation center by the rotation of the cam 5 with which the roller body 10 contacts the upper end. As a result, the intake valve 3 is pushed downwardly against the spring via the rocker arm 8 on the cam surface 19 at the lower end of the swinging member 9 to open.

  When the load in the internal combustion engine increases to a high load range, the tip of the fulcrum member 15 moves to the upper end side of the swing member 9 rather than in the middle load range indicated by the solid line. The force point length from the force point at which the upper end roller body 10 contacts the cam 5 to the fulcrum at which the tip of the fulcrum member 15 contacts the swing member 9 is shorter than the force point length in the middle load region. The operating point length from the operating point at which the cam surface 19 at the lower end of the rocking member 9 contacts the roller 18 in the rocker arm 8 to the fulcrum is longer than the operating point length in the middle load region. The swinging angle of the swinging member 9 with respect to the crank angle θ of the intake valve opening set in the cam 5 is increased, and as a result, as shown in FIG. Relative movement distance to the roller 18 is increased to L1, perform opening operation of the intake valves 3 during this long movement distance L1.

  When the load in the internal combustion engine decreases to a low load region, the tip end of the fulcrum member 15 moves to the lower end side of the swing member 9 from the middle load region indicated by the solid line, so that the power point length becomes medium. While the action point length is longer than the force point length in the load range, the action point length is shorter than the action point length in the medium load range. As shown in FIG. 5, the swing angle is reduced, and the relative movement distance L2 of the rocker arm 8 with respect to the roller 18 on the cam surface 19 at the lower end thereof is shortened. The intake valve 3 is opened.

  In other words, in the high load range, the swing angle of the swing member 9, and consequently the movement distance L1 of the cam surface 19 with respect to the roller 18, increases, so that the intake valve 3 is shown by a solid line A1 in FIG. Since the opening operation is performed with a negative profile, the maximum valve lift amount H1 is higher than the maximum valve lift amount H0 in the middle load region.

  On the other hand, in the low load region, the swinging angle of the swinging member 9 and, consequently, the moving distance L2 on the cam surface 19 is reduced, so that the intake valve 3 is shown by a two-dot chain line A2 in FIG. Therefore, the maximum valve lift amount H2 is lower than the maximum valve lift amount H0 in the middle load region.

  Thereby, the valve lift amount when the intake valve 3 is opened and operated can be automatically controlled to be large at high load and small at low load according to the load of the internal combustion engine.

  Further, the roller body 10 at the upper end of the swinging member 9 is adjusted by moving the pin shaft 11 toward and away from the cam 5 with which the roller body 10 abuts. 5 can be set very easily without requiring disassembly of the parts.

  Furthermore, by rotating the bushing body 13 fitted to the pin shaft 11 to move and adjust the swing member 9 in the longitudinal direction, the cam surface 19 and the rocker arm 8 of the swing member 9 are adjusted. The clearance between the roller 18 and the clearance between the cam surface 19 and the intake valve 3 can be set very easily without the need for disassembling the parts as described above.

  In the above-described embodiment, the cam contact portion is a roller body 10 that is eccentric with respect to the pin shaft 11 so that the cam contact portion can be adjusted by moving the pin shaft 11. On the other hand, the bushing body 13 that fits in the guide groove 14 while being rotatably fitted to the pin shaft 11 is eccentric to the pin shaft 11, so that the rotation of the bushing body 13 causes the rocking motion. The moving member 9 was configured to move and adjust in the longitudinal direction, but the present invention is not limited to such a configuration. It is possible to adjust the movement of the swing member 9 in the longitudinal direction.

  Furthermore, in the above-described embodiment, when the pin shaft 11 and the bush body 13 are fixed to be unrotatable at an arbitrary rotational position, it is needless to say that configurations other than those described above can be adopted.

It is a figure which shows embodiment in this invention. FIG. 2 is an enlarged sectional view taken along line II-II in FIG. 1. FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 2. FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 2. It is an enlarged view which shows the principal part of FIG. It is a figure which shows the profile of an intake valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Intake port 3 Intake valve 4 Intake valve spring 5 Cam 6 Cam shaft 8 Rocker arm 9 Oscillating member 10 Roller body (cam contact part)
11 Pin shaft 12 Bracket member 13 Bushing body 14 Guide groove 15 Support point member 18 Roller 19 Cam surface

Claims (3)

  A cam that rotates in conjunction with a crankshaft and a swinging member. One of the left and right side surfaces in the longitudinal direction of the swinging member has one end and the other end in the longitudinal direction of the swinging member. The fulcrum member is brought into contact with the portion between the two portions, and the contact point is configured to move to the one end portion side or the other end portion side. A cam contact portion is provided at one end, and the cam contact portion is provided on the cam so that the swinging member swings and swings in the left-right direction with the contact portion of the fulcrum member as a fulcrum by the rotation of the cam. The swinging member is provided with guide means for preventing the swinging member from moving in the longitudinal direction in a state in which the swinging rotation of the swinging member is allowed. The intake valve and the other end of the member are swung by the swinging member. A cam surface is provided that opens and operates at least one of the exhaust valves against its spring, and the cam contact portion at one end of the swinging member can be adjusted toward and away from the cam. A valve operating mechanism in an internal combustion engine, characterized in that it is configured.   A cam that rotates in conjunction with a crankshaft and a swinging member. One of the left and right side surfaces in the longitudinal direction of the swinging member has one end and the other end in the longitudinal direction of the swinging member. The fulcrum member is brought into contact with the portion between the two portions, and the contact point is configured to move to the one end portion side or the other end portion side. A cam contact portion is provided at one end, and the cam contact portion is provided on the cam so that the swinging member swings and swings in the left-right direction with the contact portion of the fulcrum member as a fulcrum by the rotation of the cam. The swinging member is provided with guide means for preventing the swinging member from moving in the longitudinal direction in a state in which the swinging rotation of the swinging member is allowed. The intake valve and the other end of the member are swung by the swinging member. Provided is a cam surface that opens and operates at least one of the exhaust valves against its spring, and further includes means for moving and adjusting the swing member in the longitudinal direction of the guide means. A valve operating mechanism in an internal combustion engine.   A cam that rotates in conjunction with a crankshaft and a swinging member. One of the left and right side surfaces in the longitudinal direction of the swinging member has one end and the other end in the longitudinal direction of the swinging member. The fulcrum member is brought into contact with the portion between the two parts, and the contact point is moved to the one end side or the other end side, and rotated to one end in the longitudinal direction of the swinging member. A roller shaft is provided on a freely pivotally supported pin shaft so that the roller body rotates together with the pin shaft. The roller body is attached to the cam, and the swinging member is brought into contact with the fulcrum member by rotation of the cam. As a fulcrum, it is abutted so as to swing and rotate in the left-right direction, and a bushing body rotatably fitted on the pin shaft is slidably fitted in the guide groove so that the swinging member can be swung. In a permitted state, the swinging member is configured to be prevented from moving in the longitudinal direction. On the other hand, the other end of the swing member is provided with a cam surface that opens and operates at least one of the intake valve and the exhaust valve against the spring by swinging and rotating in the swing member. Furthermore, the valve mechanism in the internal combustion engine, wherein the roller body and the bush body are eccentric with respect to the pin shaft.

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