JP5497487B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

  According to the present invention, a control arm having a sub cam and a rocker arm for transmitting a driving force of a valve cam to an engine valve is supported on a cylinder head so as to be swingable, and the control arm is swung by a control shaft to lift the engine valve. The present invention relates to a variable valve operating apparatus for an internal combustion engine that changes the amount.

  Such a variable valve operating apparatus for an internal combustion engine is known, for example, from Patent Document 1 below.

  In this variable valve operating apparatus, when a control arm having a sub cam assembled in advance is assembled to a cylinder head as a sub assembly, the sub cam is not fixed to the control arm, and the sub cam swings freely around the support shaft. Since it moved and interfered with other members, there was a problem that it was difficult to assemble the control arm to the cylinder head.

  In order to solve this problem, by providing a swing restricting means for restricting the swing limit of the sub cam relative to the control arm, it is possible to prevent the sub cam from loosening with respect to the control arm, and to attach the control arm to the cylinder head. A technique for improving the workability is known from Patent Document 2 below.

JP 2006-307765 A JP 2008-303765 A

  However, in the device described in Patent Document 2, the swing restricting means for restricting the swing limit of the sub cam relative to the control arm is arranged between the support shaft that pivotally supports the sub cam on the control arm and the control shaft. For this reason, there is a problem that the swing restricting means gets in the way and the control shaft cannot be brought close to the control arm, which hinders the miniaturization of the variable valve operating apparatus.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the size of the variable valve operating apparatus by bringing the control shaft closer to the control arm while ensuring the assembly of the control arm.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a control arm swingably supported by a cylinder head, a control shaft for swinging the control arm, and a support for the control arm. A sub-cam supported by a shaft and swinging by a valve-operating cam; biasing means for biasing the sub-cam in a direction to contact the valve-operating cam; and supported by the control arm and swinging by the sub-cam. In the variable valve mechanism for an internal combustion engine, comprising: a rocker arm that drives the engine valve; and a swing restricting means that restricts a swing limit around the support shaft of the sub cam by the biasing force of the biasing means. regulating means is comprised of the second contact portion provided in the control arm and the first contact portion provided on the sub cam, the subcategory Of is provided on the opposite side of the control shaft relative to the support shaft, the first, the second contact portion, an internal combustion, characterized in that arranged along the direction of the biasing force of the biasing means institutions of the variable valve device Ru been proposed.

According to the invention described in claim 2, in addition to the first aspect, the first contact portion of the sub-cam is abutting contact with the valve operating cam and cam surface for driving the rocker arm A variable valve operating apparatus for an internal combustion engine is proposed, characterized in that the variable valve operating apparatus is disposed between the two parts.

  The intake valve 13 of the embodiment corresponds to the engine valve of the present invention, and the first abutting portion 18b, the second abutting portions 20f, 20g and the support shaft 27 of the embodiment are the swing restricting means of the present invention. The second roller 32 of the embodiment corresponds to the contact portion of the present invention, and the lost motion spring 36 of the embodiment corresponds to the biasing means of the present invention.

According to the first aspect of the present invention, when the sub cam and the rocker arm are supported by the control arm that is swung by the control shaft, and the driving force of the valve cam is transmitted to the engine valve via the sub cam and the rocker arm, the control arm The valve lift of the engine valve is changed by moving the position of the support shaft of the sub cam. When the control arm that supports the sub cam, rocker arm and biasing means is assembled to the cylinder head as a subassembly, the swing restricting means restricts the sub cam biased by the biasing means from swinging around the support shaft indefinitely. By doing so, the assembling property of the control arm can be improved. Since the swing restricting means is provided on the opposite side of the control shaft with respect to the support shaft of the sub cam, the control shaft can be brought close to the control arm without being interrupted by the swing restricting means. Ru can be miniaturized.

In addition, the swing restricting means is composed of a first abutting portion provided on the sub cam and a second abutting portion provided on the control arm, and the first and second abutting portions are made of the urging force of the urging means. Because it is arranged along the direction, the load of the first contact portion of the sub cam urged by the urging means is efficiently transmitted to the second contact portion of the control arm, and the swing limit of the sub cam is reliably regulated. can do.

According to the second aspect of the present invention, the first contact portion of the sub cam is disposed between the cam surface that drives the rocker arm and the contact portion that contacts the valve cam. It is possible to increase the rigidity of the sub cam with respect to the load inputted to the first contact portion.

The vertical side view at the time of the high lift of a variable valve apparatus (1st Embodiment). The vertical side view at the time of the low lift of a variable valve apparatus (1st Embodiment). FIG. 3 is a three-direction arrow view of FIG. 1 (first embodiment). FIG. 4 is an exploded perspective view of FIG. 3 (first embodiment). FIG. 5 is a view in the direction of arrows 5 in FIG. 3 (first embodiment). FIG. 6 is a sectional view taken along line 6-6 in FIG. 5 (first embodiment). FIG. 7 is a sectional view taken along line 7-7 in FIG. 6 (first embodiment). The figure which shows the state at the time of the assembly | attachment of a control arm (1st Embodiment). The perspective view of a control arm and a subcam (2nd Embodiment). The figure which shows the state at the time of the assembly | attachment of a control arm (2nd Embodiment). The figure corresponding to the said FIG. (Third embodiment) The figure corresponding to the said FIG. (Third embodiment)

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 to 5, a pair of intake valves 13 and 13 are supported by a cylinder head 12 constituting a part of the engine body 11 so as to be openable and closable for each cylinder. The valve operating device 14 that opens and closes the intake valves 13 and 13 is displaceable in a cam shaft 16 provided with a valve operating cam 15 that drives the intake valves 13 and 13 and a plane orthogonal to the axis L1 of the cam shaft 16. A sub-cam 18 that is supported by a support shaft 17 so as to be swingable and is driven by the valve-operating cam 15, a rocker arm 19 that is driven by the sub-cam 18 and drives the intake valves 13, 13, and a camshaft 16. A control arm 20 that is supported so as to be swingable about an axis L2 parallel to the axis L1 and that supports the support shaft 17 at a position offset from the axis L2, and a drive means 21 that swings the control arm 20 are provided. Yes, the operating characteristics including the lift amount of the intake valves 13 and 13 can be changed by displacing the position of the support shaft 17 as the control arm 20 swings. That.

  The stems 13a, 13a of the intake valves 13, 13 are slidably fitted to guide cylinders 22, 22 provided in the cylinder head 12, and retainers 24, 24 provided at the upper ends of the stems 13a, 13a. The intake valves 13 and 13 are urged in the valve closing direction by the valve springs 26 and 26 interposed between the retainers 25 and 25 that contact the cylinder head 12.

  One end of the rocker arm 19 is swingably supported by the control arm 20 via a support shaft 29. Further, the other end portion of the rocker arm 19 is provided with valve contact portions 19a, 19a that contact the upper ends of the stems 13a, 13a of the intake valves 13, 13. Further, a first roller 31 is pivotally supported at the intermediate portion of the rocker arm 19 via a support shaft 34 and a needle bearing 30, and the first roller 31 is in rolling contact with the cam surface 18 a of the sub cam 18.

  The control arm 20 includes a pair of side wall portions 20a, 20a, a pair of shaft portions 20b, 20b protruding from the outer surface of the side wall portions 20a, 20a along the axis L2, and one end portions of the side wall portions 20a, 20a. The first connecting wall 20c for connecting the two and the second connecting wall 20d for connecting the other ends of the side walls 20a, 20a are integrally formed. Are supported in a swingable manner in support holes 12a, 12a (see FIG. 5).

  The support shaft 17 disposed parallel to the axis L1 of the camshaft 16 passes through the sub cam 18 disposed inside the both side walls 20a, 20a of the control arm 20, and both ends of the support shaft 17 are both side wall portions. It fixes so that 20a and 20a may be bridge | crosslinked. A cam surface 18 a that contacts the first roller 31 of the rocker arm 19 is formed in the sub cam 18, and a second roller 32 that contacts the valve cam 15 is rotatably supported via the support shaft 27 and the needle bearing 33. Is done. Therefore, the sub cam 18 swings around the support shaft 17 when the second roller 32 contacts the valve cam 15 of the cam shaft 16.

  Lost motion springs in which pressing members 35 and 35 slidably fitted to a pair of cylindrical tube portions 20e and 20e formed on the first connecting wall portion 20c are disposed on the outer periphery of the tube portions 20e and 20e, respectively. It is urged | biased by 36 and 36, and contact | abuts to the both ends of the spindle 27 which pivotally supports the 2nd roller 32. FIG. As a result, the second roller 32 of the sub cam 18 elastically contacts the valve cam 15.

  The drive means 21 includes a control shaft 39 parallel to the support shaft 17, a control cam 40 provided on the control shaft 39, a third roller 42 supported on the support shaft 29 via a needle bearing 41, and a control shaft. And an actuator 43 that rotationally drives 39 in both forward and reverse directions. An urging member 44 slidably supported by the cylinder head 12 and urged by a spring (not shown) is in contact with the lower surface of the second connecting wall portion 20d of the control arm 20, whereby the third roller 42 is It elastically contacts the control cam 40. Therefore, when the actuator 43 is driven, the control arm 20 swings around the shaft portions 20b and 20b via the control cam 40 and the third roller 42, and the position of the support shaft 17 that supports the sub cam 18 on the control arm 20 changes. .

  As is apparent from FIGS. 6 to 8, a pair of first contact portions 18b and 18b are provided on both sides of the cam surface 18b below the support shaft 17 of the sub cam 18, and the first contact portions 18b. , 18b are provided on the inner surfaces of both side walls 20a, 20a of the control arm 20. Therefore, as shown in FIG. 8, when the control arm 20 is assembled as a subassembly, the sub cam 18 urged around the support shaft 17 by the lost motion springs 36, 36 has the first contact portions 18b, 18b thereof. By abutting on the second abutting portions 20 f and 20 f of the control arm 20, the counterclockwise swing limit of the sub cam 18 with respect to the control arm 20 can be regulated.

  Next, the operation of the first embodiment of the present invention having the above configuration will be described.

  When the intake valves 13 and 13 are driven to open and close by the valve drive cam 15 provided on the camshaft 16, the sub cam 18 is pressed at both ends of the support shaft 27 by the elastic force of the lost motion springs 36 and 36. The second roller 32 is pressed against the valve cam 15 by being urged around 17. The control arm 20 is pressed against the shafts 20b and 20b by pressing the second connecting wall portion 20d with the urging member 44, so that the third roller 42 is pressed against the control cam 40 of the control shaft 39. The The rocker arm 19 presses the first roller 31 against the cam surface 18a of the sub cam 18 and urges the rocker arm 19 around the support shaft 29, so that the valve contact portions 19a and 19a are the stems 13a and 13a of the intake valves 13 and 13, respectively. It is press-contacted to the upper end of.

  When the control arm 20 is driven to the position shown in FIG. 1 by the driving means 21 including the actuator 43, the control shaft 39, the control cam 40 and the third roller 42, the cam surface 18 a of the sub cam 18 swinging around the support shaft 17. Since the rocker arm 19 is greatly swung at a portion far from the support shaft 17, the drive amount in the valve opening direction of the upper ends of the stems 13a, 13a of the intake valves 13, 13 is increased, and the lift amount of the intake valves 13, 13 is increased. Is the maximum.

  When the control arm 20 is driven to the position shown in FIG. 2 by the driving means 21, the cam surface 18 a of the sub cam 18 that swings around the support shaft 17 causes the rocker arm 19 to swing slightly at a portion near the support shaft 17. Therefore, the drive amount in the valve opening direction of the upper ends of the stems 13a, 13a in the intake valves 13, 13 is reduced, and the lift amount of the intake valves 13, 13 is minimized.

  The lift amount of the intake valves 13 and 13 is changed by swinging the control arm 20 around the shaft portions 20 b and 20 b by the driving means 21, but the valve cam 15 is moved to the second roller 32 by the swing of the control arm 20. Since the contact timing also changes, the opening / closing timing of the intake valves 13, 13 also changes.

  By the way, the sub cam 18, the rocker arm 19, the pressing members 35, 35, the lost motion springs 36, 36, etc. are assembled to the control arm 20 in advance to form a subassembly as shown in FIG. It will be assembled to the head 12.

  At this time, assuming that the sub cam 18 pivotally supported by the support shaft 17 on the control arm 20 is in a freely swingable state, the sub cam 18 is moved counterclockwise from the original assembly position shown in FIGS. There is a problem that the sub cam 18 interferes with other members and the workability of assembling the control arm 20 to the cylinder head 12 is lowered.

  However, in the present embodiment, the sub cam 18 biased by the elastic force of the lost motion springs 36, 36 has the first contact portions 18b, 18b provided on the sub cam 18 as the second contact portions 20f, 20f of the control arm 20. 8, the swinging end of the sub cam 18 in the counterclockwise direction in FIG. 8 is restricted, so that the sub cam 18 is prevented from swinging indefinitely with respect to the control arm 20. Therefore, when the control arm 20 is assembled to the cylinder head 12, the looseness of the sub cam 18 can be restricted to improve the assemblability of the control arm 20.

  When the internal combustion engine is operated with the control arm 20 assembled to the cylinder head 12, the first contact portions 18b and 18b and the second contact portions 20f and 20f do not contact each other (see FIG. 1 and FIG. 1). (See FIG. 2).

  As apparent from FIG. 8, the first contact portions 18 b and 18 b of the sub cam 18 and the second contact portions 20 f and 20 f of the control arm 20 are on the opposite side of the control shaft 39 with respect to the support shaft 17 of the sub cam 18. Since it is provided, the control shaft 39 can be disposed close to the control arm 20 without being obstructed by the first and second contact portions 18b, 18b; 20f, 20f, and the variable valve operating device can be downsized. Can contribute.

  Furthermore, since the second contact portions 20f and 20f of the control arm 20 are disposed outside the swing locus of the first contact portions 18b and 18b of the sub cam 18 with the support shaft 17 as the center, Interference with other members can be avoided by suppressing the swing locus of the portions 18b and 18b to be small. Moreover, since the first contact portions 18b, 18b of the sub cam 18 are disposed between the cam surface 18a that drives the rocker arm 19 and the second roller 32 that contacts the valve cam 15, the cam surface 18a and the second roller The rigidity of the sub cam 18 with respect to the load input to 32 can be increased by the first contact portions 18b, 18b.

  Next, a second embodiment of the present invention will be described based on FIG. 9 and FIG.

  The second embodiment is different from the first embodiment in the shape and arrangement of the first contact portions 18b, 18b of the sub cam 18 and the second contact portions 20f, 20f of the control arm 20. The configuration is the same as in the first embodiment. That is, the first abutting portions 18b and 18b are constituted by both end portions of one pin penetrating the sub cam 18, and the second abutting portions 20f and 20f are planted on the inner surfaces of both side wall portions 20a and 20a of the control arm 20. It consists of two pins.

  As is clear from FIG. 9, contrary to the first embodiment, the second contact portions 20 f and 20 f of the control arm 20 are the first contact portions 18 b and 20 b of the sub cam 18 centered on the support shaft 17. Since it arrange | positions inside the rocking locus of 18b, the rocking locus of the 1st contact parts 18b and 18b will become large. However, the sub cam 18 urged by the lost motion springs 36, 36 swings counterclockwise around the support shaft 17, and the first and second contact portions 18b, 18b; 20f, 20f contact each other. When the swing limit of the sub cam 18 is restricted, the first and second contact portions 18b, 18b; 20f, 20f are substantially in the same direction as the direction of action of the elastic force of the lost motion springs 36, 36 (see arrow A). Therefore, the elastic force is efficiently supported by the contact of the first and second contact portions 18b and 18b; 20f and 20f, and the swing limit of the sub cam 18 can be reliably regulated.

  The operational effects of the second embodiment other than those described above are the same as the operational effects of the first embodiment.

  Next, a third embodiment of the present invention will be described based on FIG. 11 and FIG.

  In the third embodiment, the first contact portion of the swing restricting means is constituted by a support shaft 27 provided on the sub cam 18, and the second contact portions 20g, 20g capable of contacting the support shaft 27 are provided. Projecting in a triangular shape above both side walls 20a, 20a of the control arm 20. Therefore, when the sub cam 18 biased by the lost motion springs 36, 36 swings counterclockwise around the support shaft 17, both ends of the support shaft 27, which is the first contact portion, become the second contact of the sub cam 20. By restricting the swing limit of the sub cam 18 by abutting against the portions 20g and 20g, when the control arm 20 is assembled to the cylinder head 12, the loose movement of the sub cam 18 is restricted and the assemblability of the control arm 20 is improved. it can.

  As is apparent from FIG. 11, a support shaft 27 (with respect to a straight line b that is orthogonal to a straight line a that connects the axis of the control shaft 39 and the axis of the support shaft 17 that pivotally supports the sub cam 18 and that passes through the support shaft 17. The contact point c between the first contact portion) and the second contact portions 20g, 20g is located on the opposite side of the control shaft 39. With this arrangement, the control shaft 39 can be arranged close to the control arm 20 without being obstructed by the first and second contact portions 27, 20g, and 20g, which contributes to downsizing of the variable valve operating apparatus. Can do. Further, by using the support shaft 27 of the sub cam 18 as the first contact portion, it is not necessary to provide a special first contact portion, and the structure can be simplified.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, although the valve operating devices for the intake valves 13, 13 have been described in the above embodiments, the present invention is also applicable to a valve operating device for an exhaust valve that is an engine valve.

  In the third embodiment, the second contact portions 20g, 20g are provided on both side wall portions 20a, 20a of the control arm 20, but the second contact portion 20g is provided on one side wall portion of the control arm 20. You may provide only in 20a.

12 Cylinder head 13 Intake valve (engine valve)
15 Valve cam 17 Support shaft 18 Sub cam 18a Cam surface 18b First contact portion (swing restricting means)
19 Rocker arm 20 Control arm 20f Second contact portion (swing restricting means)
20g 2nd contact part (oscillation control means)
27 Support shaft (rocking restricting means)
32 Second roller (contact portion)
36 Lost motion spring (biasing means)
39 Control shaft

Claims (2)

A control arm (20) swingably supported by the cylinder head (12);
A control shaft (39) for swinging the control arm (20);
A sub cam (18) supported by the control arm (20) via a support shaft (17) and swinging by a valve cam (15);
An urging means (36) for urging the sub cam (18) in a direction in contact with the valve cam (15);
A rocker arm (19) supported by the control arm (20) and swinging by the sub cam (18) to drive the engine valve (13);
The internal combustion engine is provided with swing restricting means (18b, 20f; 27, 20g) for restricting a swing limit around the support shaft (17) of the sub cam (18) by the biasing force of the biasing means (36). In the variable valve mechanism,
The swing restricting means includes a first contact portion (18b, 27) provided on the sub cam (18) and a second contact portion (20f, 20g) provided on the control arm (20). And provided on the opposite side of the control shaft (39) with respect to the support shaft (17) of the sub cam (18) ,
The variable valve for an internal combustion engine, wherein the first and second contact portions (18b, 20f; 27, 20g) are arranged along a direction of a biasing force of the biasing means (36). equipment. The first contact portion (18b) of the sub cam (18) is between a cam surface (18a) that drives the rocker arm (19) and a contact portion (32) that contacts the valve cam (15). The variable valve operating apparatus for an internal combustion engine according to claim 1 , wherein

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