JP2020033872A - Variable valve mechanism of internal combustion engine - Google Patents

Abstract

To adjust a variation of a valve lift amount, or a variation of a valve lift operation angle in a cylinder, or between the cylinders without imposing a time and labor, and without increasing a cost, in a variety of variable valve mechanisms including variation control oscillation arms.SOLUTION: A variable valve mechanism of an internal combustion engine is constituted of a plurality of variable valve members including oscillation arms 10 for variably controlling a valve lift amount, or a valve lift operation angle, and rollers 18 abutting on the other variable valve member are pivoted to the oscillation arms 10 so as to be rotatable by roller pins 20. A variation adjustment device comprises columnar pin shafts 21, 22 inserted into the oscillation arms 10, and columnar roller support parts 23 inserted into the rollers 18, and also includes the roller pins 20 which are decentered to pin shafts at the roller support parts, and roller pin anchoring structures for anchoring the roller pins 20 so as not to rotate to the oscillation arms 10.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a variable valve mechanism for an internal combustion engine.

  In a variable valve operating mechanism of an internal combustion engine, a variation in the valve lift amount or a valve lift operating angle occurs in a cylinder or between cylinders due to a manufacturing variation of each component. Therefore, an adjusting means for adjusting the variation is required. is there.

  For example, a variable valve mechanism described in Patent Document 1 is known under the name of Valvetronic (registered trademark of BMW), and an intermediate lever is interposed between a cam and a rocker arm, and an intermediate lever is provided by a step motor. This is a mechanism in which the lift amount of the valve is continuously changed by adjusting the position of the light lever (Patent Document 1). As the adjusting means in the same mechanism, an intermediate lever and a rocker arm each having a rank slightly different in size are prepared, and the intermediate lever and the rocker arm of the cylinder that needs to be adjusted are replaced with those of a suitable rank. I have.

  However, this adjusting means requires assembling of the variable valve mechanism for each adjustment, which is troublesome. In addition, the number of intermediate levers and rocker arms corresponding to the number of ranks must be prepared, thereby increasing costs.

  The variable valve mechanism described in Patent Literature 2 is known under the name of Valvematic (registered trademark of Toyota Motor Corporation). An input member pressed by a cam and an output member pressing a valve are each provided with a slider. The input side helical spline and the output side helical spline are engaged with each other, and the slider is slid in conjunction with the push / pull of the control shaft. This is a mechanism in which the lift amount of the valve is continuously changed by converting into a phase difference (Patent Document 2). As the adjusting means in the mechanism, a shim having a structure in which a shim is interposed between the input member and the output member or between the output member and the cam carrier, and a shim with a slightly different thickness is prepared, The input member, the output member, and the slider are shifted in the push-pull direction of the control shaft by replacing the shim of the cylinder that needs to be adjusted with a shim of a suitable rank.

  However, this adjusting means can be adopted only in a variable valve mechanism having this mechanism, and cannot be adopted in a variable valve mechanism having another mechanism.

JP-T-2004-521234 JP 2004-340140 A

  In view of the above, an object of the present invention is to use a variable valve mechanism including a swing arm for variable control, which requires a great deal of time and effort to reduce the variation in the valve lift amount or valve lift operating angle within a cylinder or between cylinders. It is to be able to adjust without being adjusted.

The present invention includes a plurality of valve operating members including a cam and a swing arm provided between the cam and the valve for variably controlling a valve lift amount or a valve lift operating angle. Is a variable valve mechanism of an internal combustion engine in which a roller abutting on another valve member is rotatably mounted by a roller pin,
A variation adjustment device that adjusts the variation of the valve lift amount or the valve lift operating angle within the cylinder or between the cylinders,
A roller pin having a cylindrical pin shaft portion inserted into the swing arm and a cylindrical roller support portion inserted into the roller, wherein the roller support portion is eccentric with respect to the pin shaft;
And a roller pin fastening device for fastening the roller pin to the swing arm so that the roller pin does not rotate in a state where the rotation direction position of the roller pin is adjusted.

  According to the present invention, in various types of variable valve mechanisms including a swing arm for variable control, variations in the valve lift amount or valve lift operating angle within a cylinder or between cylinders can be reduced without much labor and cost. Can be adjusted.

1A and 1B show a variable valve mechanism according to a first embodiment, wherein FIG. 1A is a front view, FIG. 1B is a left side view, and FIG. 1C is a right side view. 2A and 2B are sectional views taken along line II-II for explaining variation adjustment, FIGS. 2C and 2D are perspective views of a roller pin, and FIG. 2E is an end view of the roller pin. FIGS. 3A and 3B are cross-sectional views illustrating an example of a valve lift after variation adjustment. FIG. 3A is a cross-sectional view of a base circle, FIG. 3B is a low lift state, and FIG. . FIGS. 4A and 4B are cross-sectional views illustrating another valve lift after variation adjustment. FIG. 4A is a cross-sectional view at the time of a base circle, FIG. 4B is a cross-sectional view at the time of a low lift, and FIG. FIGS. 5A and 5B show a variable valve mechanism according to the second embodiment, wherein FIGS. 5A and 5B are cross-sectional views for explaining variation adjustment, FIGS. 5C and 5D are perspective views of a roller pin, and FIG. FIG.

  The swing arm may variably control either the valve lift amount or the valve lift operating angle, or may variably control both of them.

  The other valve operating member with which the roller is in contact is not particularly limited, and examples thereof include a cam and an intervening arm between the cam and the swing arm.

Although the structure of the roller pin fastening device is not particularly limited, the following embodiment [1] or [2] can be exemplified.
[1] In the roller pin fastening structure, the male screw of the pin shaft is screwed into the female screw hole of the swing arm, and the nut is screwed into the male screw of the pin shaft protruding outward from the swing arm. This is a structure that is fastened to the outer surface of the swing arm. According to this aspect, unlike the above-described background art, the variation can be adjusted without exchanging parts.

[2] In the roller pin fastening structure, the male screw of the pin shaft is screwed into the female screw hole of the swing arm, and a ring is formed between the head having a larger diameter than the pin shaft of the roller pin and the outer surface of the swing arm. This is a structure in which an adjustment shim in the shape of a circle is interposed, and the head is fastened to the outer surface of the swing arm via the adjustment shim. According to this aspect, it is necessary to replace the adjustment shim, but the work of adjusting the variation can be simplified as compared with the aspect of [1].

  First Embodiment A first embodiment of the present invention will be described with reference to FIGS. The structure and shape of each part in each embodiment are mere examples, and can be changed as appropriate without departing from the spirit of the invention.

  The variable valve mechanism of the internal combustion engine according to the present embodiment includes a cam 1, a rocker arm 3 that presses an intake or exhaust valve 40, and a portion from the cam 1 to the valve 40 (in this example, the cam 1 and the rocker arm 3). And a swing arm 10 for variably controlling a valve lift amount or a valve lift working angle provided between the swing arm 10 and the swing arm 10. In the example, a roller 18 that comes into contact with the cam 1) is rotatably mounted on a roller pin 20. Further, a swing arm control device is provided that continuously variably controls the valve lift amount or the valve lift working angle by displacing the swing center of the swing arm 10.

  Further, as a variation adjusting device for adjusting the variation of the valve lift amount or the valve lift operating angle within the cylinder or between the cylinders, the cylindrical pin shaft portions 21 and 22 inserted into the swing arm 10 and the rollers 18 are inserted. A roller support portion 23 having a cylindrical roller support portion 23, the roller support portion 23 being eccentric with respect to the pin shafts 21 and 22, and the roller pin 20 being swung in a state where the rotational direction position of the roller pin 20 is adjusted. And a roller pin fastening structure for fastening to the arm 10 so as not to rotate.

  The details of these components will be described below. Note that a direction parallel to the front and rear direction of the rocker arm 3 is simply referred to as front and rear direction, and a direction parallel to the width direction of the rocker arm 3 is simply referred to as width direction.

[Cam 1]
The cam 1 includes a base circle that is circular in a side view and a nose protruding from the base circle, and the nose causes a valve lift. The cam 1 is formed on a camshaft 2 orthogonal to the base circle. The camshaft 2 extends in the width direction and is rotatably supported by a journal (not shown) of a cylinder head.

[Rocker arm 3]
The rocker arm 3 extends forward and backward below the camshaft 2, and can swing by a hemispherical concave portion 4 formed on the lower surface of the rear portion being placed on a hemispherical convex portion of the lash adjuster 5. Supported. The lower surface of the tip of the rocker arm 3 is a pressing portion 6 that presses the upper end of the valve 40. A rocker roller 7 is rotatably mounted on a roller shaft 8 at an intermediate portion in the front-rear direction of the rocker arm 3. The rocker arm 3 swings to drive the valve 40 when the driving force is transmitted to the rocker roller 7.

[Swinging arm 10]
The swing arm 10 is pivotally mounted on the support shaft 11. The support shaft 11 extends in the width direction behind and above the camshaft 2, and is attached to a journal (not shown) of the cylinder head so as to be movable in a forward and backward direction which is a shaft radial direction.

  The swing arm 10 is an intermediate arm having a substantially L-shape when viewed from the side, including an arm vertical portion 12 extending vertically and an arm horizontal portion 13 extending forward from a lower portion of the arm vertical portion 12. The arm vertical portion 12 includes a first side wall 14 and a second side wall 15 separated from each other in the width direction, and the arm horizontal portion 13 includes a first side wall 14 and a second side wall 15 continuing from the arm vertical portion 12 and the side walls 14, 15. And a bottom wall 16 connecting the lower portions of the bottom wall.

  When the support shaft 11 is inserted into the support hole 17 formed on the first side wall 14 and the second side wall 15 of the arm vertical portion 12, the swing arm 10 swings forward and backward about the support shaft 11. It is possible. A roller 18 that comes into contact with the cam 1 is rotatably mounted on a roller pin 20 at a vertically intermediate portion of the arm vertical portion 12.

  The arm lateral portion 13 extends forward so as to enter between the cam 1 and the rocker roller 7, and a pressing surface 19 for pressing the rocker roller 7 is formed on the lower surface of the bottom wall 16. The pressing surface 19 has an arc portion 19 a extending in the circumferential direction around the support shaft 11, and a protruding portion that continuously increases from the tip of the arc portion 19 a in the direction away from the support shaft 11 toward the front. 19b. While the arc portion 19a rests on the rocker roller 7, the rocker arm 3 does not swing and the valve 40 does not lift. Then, when the projecting portion 19b hits the rocker roller 7, the rocker arm 3 swings and the valve 40 is lifted.

  One end of a spring 28 that urges the arm vertical portion 12 toward the cam 1 is in contact with the rear side of the arm vertical portion 12 of the swing arm 10, and the roller 18 is always in contact with the cam 1.

[Variation adjustment device]
As shown in FIG. 2 and the like, the roller pin 20 has a cylindrical first pin shaft portion 21 inserted into the first hole 14 a of the first side wall 14 and a circle inserted into the second hole 15 a of the second side wall 15. It is composed of a columnar second pin shaft portion 22 and a cylindrical roller support portion 23 inserted between the side walls 14 and 15 into the roller hole of the roller 18, and these are integrally formed. The center axis of the first pin shaft 21 and the center axis of the second pin shaft 22 are a common pin axis P, and the roller axis Q, which is the center axis of the roller support 23, is predetermined with respect to the pin axis P. That is, the roller support portion 23 (and the roller 18) is eccentric with respect to the pin shafts 21 and 22.

The inner surface of the first hole 14a and the outer surface of the first pin shaft 21 are smooth surfaces. A hexagonal recess 24 into which a hexagonal wrench (not shown) can be fitted is formed on the end surface of the first pin shaft 21.
A female screw 25 is formed on the inner surface of the second hole 15a, and a male screw 26 is formed on the outer surface of the second pin shaft 22, and the male screw 26 is screwed into the female screw 25. The second pin shaft portion 22 is formed to have a length protruding outward from the second side wall 15 by the length of the nut 27, and the nut 27 is screwed into the male screw 26 at the protruding portion.
The structure between the roller hole of the roller 18 and the roller support portion 23 is a bearing structure, and the type of the bearing is not particularly limited. Can be illustrated. However, rolling bearings with low friction are preferred.

  In the roller pin fastening structure, the male screw 26 of the second pin shaft portion 22 is screwed into the female screw 25 of the second hole 15a, and the nut 27 is screwed into the male screw 26 projecting outward from the second side wall 15. 27 is a structure which is fastened to the outer side surface of the second side wall 15.

  To fix the roller pin 20 to the swing arm 10, first, the nut 27 is loosened from the second side wall 15, and a hexagon wrench (not shown) is fitted into the hexagonal recess 24 to rotate the roller pin 20. For example, as shown by a change from the relatively small tightening amount of the male screw 26 (a) in FIG. 2 to the relatively large tightening amount of the male screw 26 (b) in FIG. Since the position in the rotation direction of the roller pin 20 changes, the position in the rotation direction can be easily adjusted. If the nut 27 is tightened to the second side wall 15 while holding the adjusted position of the roller pin 20 in the rotation direction, the roller pin 20 can be fixed to the swing arm 10 so as not to rotate.

[Swing arm control device]
The swing arm control device includes a control shaft 31 extending in the width direction immediately behind the support shaft 11, provided on the control shaft 31 and abutting on the support shaft 11, and the amount of protrusion from the control shaft 31 is continuous in the rotation direction. A control cam 32 having a profile that gradually increases, and a rotation device (not shown) that controls the rotation of the control shaft 31 within one rotation to change the contact portion of the control cam 32 that contacts the support shaft 11. It is comprised including. The support shaft 11 is pushed by the projecting amount of the control cam 32 at the changed contact portion, and the swing center of the swing arm 10 is displaced in the forward and backward directions. The operating angle can be continuously variably controlled.

  The variable valve mechanism according to the first embodiment configured as described above operates the valve operating by adjusting the variation of the valve lift amount or the valve lift operating angle as follows.

  FIG. 3 shows a state in which the rotation direction of the roller pin 20 is adjusted so that the roller axis Q is located on the opposite side of the cam 1 with respect to the pin axis P. 3 shows a state when the vehicle is fastened so as not to rotate. At this time, the arm vertical portion 12 approaches the cam 1 relatively, and the phase of the pressing surface 19 that contacts the rocker roller 7 shifts backward as compared with the case of the next FIG.

  FIG. 4 shows a state in which the rotation direction of the roller pin 20 is adjusted so that the roller axis Q is positioned on the cam 1 side with respect to the pin axis P, and the roller pin 20 is not rotated by the swing arm 10 by the roller pin fastening structure. FIG. At this time, as compared with the case of FIG. 3 above, the arm vertical portion 12 is separated from the cam 1, and the phase of the pressing surface 19 in contact with the rocker roller 7 shifts forward. 4A and 4B, the arm lateral portion 13 in FIGS. 3A and 3B is also indicated by a two-dot chain line.

  Between the state shown in FIG. 3 and the state shown in FIG. 4, the rotational position of the roller pin 20 can be adjusted arbitrarily, and the phase shift of the pressing surface 19 can be arbitrarily changed.

3 (a) and 4 (b) show that the control shaft 31 is slightly rotated and the portion of the control cam 32 where the protrusion amount is small pushes the support shaft 11 so that the support shaft 11 This shows a case where the swing center is slightly displaced forward.
As shown in (a), when the pace circle of the cam 1 contacts the roller 18, even if the phase of the pressing surface 19 is different between FIG. 3 and FIG. Since 19a is applied to the rocker roller 7, the rocker arm 3 does not swing and the valve does not lift.
As shown in (b), when the nose of the cam 1 presses the roller 18, the swing arm 10 swings, and the projection 19b of the pressing surface 19 is applied to the rocker roller 7, so that the rocker arm 3 swings small. The valve then lifts low. At this time, since the phase of the pressing surface 19 is different between FIG. 3 and FIG. 4 as described above, the valve lift amount and the valve lift working angle are larger in FIG. 4B than in FIG. Large (meaning it has been greatly adjusted).

  Next, in (c) of FIGS. 3 and 4, the control shaft 31 is further rotated, and the maximum portion of the control cam 32 that protrudes pushes the support shaft 11, and the support shaft 11 swings. This shows the case where the center is displaced the most toward the front. At this time, when the nose of the cam 1 presses the roller 18, the front side of the protruding portion 19 b of the pressing surface 19 is applied to the rocker roller 7 as compared with each of (b) in FIGS. Therefore, the rocker arm 3 swings greatly, and the valve lifts to the maximum. Also at this time, because of the phase difference between FIG. 3 and FIG. 4 as described above, the valve lift amount and the valve lift working angle are larger (larger) in FIG. 4 (c) than in FIG. 3 (c). Has been adjusted).

  As described above, in a state where the rotational direction position of the roller pin 20 is adjusted, the roller pin 20 is fixed to the swing arm 10 by the roller pin fixing structure so as not to rotate, thereby adjusting the valve lift amount and the valve lift working angle. Therefore, this adjustment can be used for adjusting the variation of the valve lift amount or the valve lift operating angle within the cylinder or between the cylinders.

  The time points (a) and (b) and the time point (c) exemplify two points in a continuously variable manner. The rotation of the control cam 32 causes the support shaft to rotate. By continuously displacing the swing center of 11, the valve lift amount and the valve lift operating angle can be continuously changed.

  According to the first embodiment, in various types of variable valve mechanisms including the swing arm 10 for variable control, variations in the valve lift amount or the valve lift operating angle within the cylinder or between the cylinders require much labor and cost. Can be adjusted without the need. Further, unlike the above-described background art, the variation can be adjusted without replacing components.

  As shown in FIG. 5, the second embodiment of the present invention differs from the first embodiment only in the roller pin 20 and the roller pin fastening structure, and is otherwise the same as the first embodiment.

  The roller pin 20 includes a first pin shaft 21, a second pin shaft 22, and a roller support 23, similarly to the first embodiment, and further includes an end portion of the first pin shaft 21 from the first pin shaft 21. Also include a large diameter head 29, which is integrally formed. A hexagonal recess 24 is formed in the head 29. The second pin shaft portion 22 is shorter than the second pin shaft portion 22 of the first embodiment because the second pin shaft portion 22 is not screwed with the nut 27. The rest of the roller pin 20 is the same as the roller pin 20 of the first embodiment.

  In the roller pin fastening structure, the male screw 26 of the second pin shaft 22 is screwed into the female screw 25 of the second hole 15 a of the second side wall 15, and a ring-shaped adjustment shim is provided between the head 29 and the first side wall 14. In this structure, the head 30 is fastened to the outer surface of the first side wall 14 via the adjustment shim 30. Adjustment shims 30 having ranks with slightly different thicknesses are prepared, and adjustment shims 30 of a suitable rank are selected and interposed.

  To fix the roller pin 20 to the swing arm 10, a hexagon wrench is fitted into the hexagonal recess 24 and the roller pin 20 is rotated. For example, as shown in FIG. 5 as a change from (a) in which the relatively thick adjustment shim 30 is interposed to (b) in which the relatively thin adjustment shim 30 is interposed, according to the thickness of the adjustment shim 30. As a result, the amount of tightening of the male screw 26 when the head 29 is tightened changes, and the position in the rotation direction of the roller pin 20 changes, so that the position in the rotation direction can be easily adjusted. When the head 29 is tightened, the roller pin 20 can be fixed to the swing arm 10 so as not to rotate, so that the nut 27 as in the first embodiment is unnecessary.

  As described above, the roller pin 20 is fastened to the swing arm 10 by the roller pin fastening structure in a state where the rotation direction position of the roller pin 20 is adjusted, so that the valve lift amount can be reduced in the same manner as in the first embodiment. In addition, since the valve lift operating angle can be adjusted, this change can be used for adjusting the valve lift amount or the variation of the valve lift operating angle within a cylinder or between cylinders.

  According to the second embodiment as well, in various types of variable valve mechanisms including the swing arm 10 for variable control, variations in the valve lift amount or the valve lift operating angle within the cylinder or between the cylinders require much labor and cost. Can be adjusted without. Further, although it is necessary to replace the adjustment shim 30, the work of adjusting the variation can be simplified as compared with the first embodiment.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be embodied with appropriate modifications without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 Cam 3 Rocker arm 10 Swing arm 11 Support shaft 12 Arm vertical part 13 Arm lateral part 14 1st side wall 14a 1st hole 15 2nd side wall 15a 2nd hole 16 Bottom wall 17 Support hole 18 Roller 19 Pressing surface 19a Arc 19b Projection 20 Roller pin 21 First pin shaft 22 Second pin shaft 23 Roller support 27 Nut 29 Head 30 Adjustment shim 31 Control shaft 32 Control cam 40 Valve P Pin axis Q Roller axis

Claims (3)

A plurality of valve operating members including a cam (1) and a swing arm (10) provided between the cam (1) and the valve (40) for variably controlling a valve lift amount or a valve lift operating angle. And a roller (18) abutting against another valve operating member (1) is rotatably mounted on the swing arm (10) by a roller pin (20).
A variation adjustment device that adjusts the variation of the valve lift amount or the valve lift operating angle within the cylinder or between the cylinders,
A pin shaft (21, 22) including a cylindrical pin shaft portion (21, 22) inserted into the swing arm (10) and a cylindrical roller support portion (23) inserted into the roller (18). A roller pin (20) whose roller support (23) is eccentric with respect to
A roller pin fastening device for fastening the roller pin (20) to the swing arm (10) so as to prevent the roller pin (20) from rotating in a state in which the rotation direction position of the roller pin (20) is adjusted; Variable valve mechanism of the engine.   In the roller pin fixing structure, the male screw (26) of the pin shaft (22) is screwed into the female screw hole (25) of the swing arm (10), and the pin shaft protrudes outward from the swing arm (10). The variable valve of an internal combustion engine according to claim 1, wherein a nut (27) is screwed into the external thread (26) of the portion (22), and the nut (27) is fastened to an outer surface of the swing arm (10). mechanism.   In the roller pin fastening structure, the male screw (26) of the pin shaft (22) is screwed into the female screw hole (25) of the swing arm (10), and has a larger diameter than the pin shaft (21) of the roller pin (20). A ring-shaped adjustment shim (30) is interposed between the head (29) of the swing arm (10) and the outer surface of the swing arm (10), and the head (29) is swung through the adjustment shim (30). 2. The variable valve mechanism for an internal combustion engine according to claim 1, wherein the variable valve mechanism is a structure that is fastened to an outer surface of (10).

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