JP2007138782A - Variable valve mechanism of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable value mechanism which facilitates the precise position adjustment of an input part and output parts. <P>SOLUTION: The variable valve mechanism of an internal combustion engine is provided with a support pipe 22A, the input part 24, the output parts 26 and 28, and a control shaft 32. The variable valve mechanism changes the oscillating phase difference of the output parts 26 and 28 with the input part 24 by moving the control shaft 32 in the axial direction restricting the movement of the input part 24 and the output parts 26 and 28 in the axial direction so as to change the valve characteristic of the engine. The support pipe 22A is provided with a flange 34A as a restricting part to restrict the movement of the input part 24 and the output parts 26 and 28 to one side of the axial direction, and provided in each cylinder 2 in such a state that the own position can be adjusted in the axial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

2. Description of the Related Art A variable valve mechanism for an internal combustion engine that changes valve characteristics according to engine operating conditions is known (see, for example, Patent Document 1).
FIG. 3 shows a planar structure of the mediation drive mechanism 20 constituting the variable valve mechanism.

  As shown in FIG. 3, the support pipe 122 fixed to the cylinder head 2 includes an input unit 24 that swings around the support pipe 122 based on the rotation of the cam 6 fixed to the camshaft 4, and an input. Output portions 26 and 28 that swing about the support pipe 122 as the portion 24 swings are provided. The output units 26 and 28 transmit driving force to the engine valve via a rocker arm (not shown).

  The input unit 24 includes input arms 24c and 24d that support the cam 6 and a roller 24b that slides, and an input gear 24e. A helical spline is formed on the inner peripheral surface of the input gear 24e. The output units 26 and 28 have output arms 26c and 28c for transmitting driving force to a rocker arm (not shown) and output gears 26e and 28e, and helical splines are formed on the inner peripheral surfaces of the output gears 26e and 28e. . The helical splines of the input gear 24e and the helical splines of the output gears 26e and 28e are opposite in the inclination direction of the teeth.

  A slider gear 30 is fitted to the outer periphery of the support pipe 122 so as to be movable in the axial direction. Helical splines are formed on the outer peripheral surface of the slider gear 30 corresponding to the helical splines of the input gear 24e and the output gears 26e and 28e. A control shaft 32 is inserted into the support pipe 122 so as to be movable in the axial direction. The slider gear 30 and the control shaft 32 are connected by an engagement pin (not shown). Therefore, when the control shaft 32 moves in the axial direction, the slider gear 30 also moves in the axial direction in conjunction with it.

  When the slider gear 30 moves in the axial direction in this way, the input portion 24 and the output portions 26 and 28 whose movement in the axial direction is restricted rotate around the support pipe 122 by the action of the helical spline. Here, since the helical splines of the input gear 24e and the helical splines of the output gears 26e and 28e are opposite in inclination direction, the input portion 24 and the output portions 26 and 28 rotate in opposite directions. To do. As a result, the swing phase difference of the output units 26 and 28 with respect to the input unit 24 is changed, and the valve characteristics such as the maximum lift amount and valve working angle of the engine valve are changed.

  By the way, when the input unit 24 and the output units 26 and 28 are assembled in a state in which the movement in the axial direction is restricted, the axial position of the control shaft 32 and the oscillation phase of the input unit 24 and the output units 26 and 28 are determined. It is necessary to set the relationship accurately. Here, the slider gear 30 is connected to the control shaft 32, and the input gear 24e of the input unit 24 and the output gears 26e and 28e of the output units 26 and 28 are meshed with the slider gear 30, respectively. When the slider gear 30 is fixed, the rocking phases of the input unit 24 and the output units 26 and 28 change according to the axial positions of the input unit 24 and the output units 26 and 28 with respect to the slider gear 30. To do. Therefore, in order to accurately set the relationship between the axial position of the control shaft 32 and the oscillation phase of the input unit 24 and the output units 26 and 28, the shafts of the input unit 24 and the output units 26 and 28 with respect to the slider gear 30 are used. It is necessary to set the direction position accurately.

Therefore, conventionally, when the input unit 24 and the output units 26 and 28 are assembled in a state where the axial positions of the control shaft 32 and the slider gear 30 are fixed, as shown in FIG. The size of the gap with the side surface of the bearing 8 is adjusted by the shim 10. As a result, by selecting the shim 10 having an appropriate thickness, the relationship between the axial position of the control shaft 32 and the oscillation phase of the input unit 24 and the output units 26 and 28 can be accurately set.
JP 2001-263015 A

  However, when setting the axial position of the input unit 24 and the output units 26 and 28 with respect to the slider gear 30 using the shim 10 as described above, it is necessary to prepare a large number of shims having different thicknesses. Further, the shim 10 is inserted to check the oscillation phase of the input unit 24 and the output units 26 and 28. If this is inappropriate, the shim 10 is removed and another shim is inserted again to check. Need to be repeated. For this reason, the operation of setting the relationship between the axial position of the control shaft 32 and the oscillation phases of the input unit 24 and the output units 26 and 28 is complicated.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a variable valve mechanism for an internal combustion engine that can easily and accurately adjust the positions of an input unit and an output unit. .

Hereinafter, means for solving the above-described object and its operation and effects will be described.
According to the first aspect of the present invention, there is provided a support pipe that is fixed to the cylinder head, an input portion that swings around the support pipe based on rotation of the cam, and the support pipe that is moved along with the swing of the input portion. The input section and the output section include an output section that swings to the center and transmits a driving force to the engine valve, and a control shaft that is disposed inside the support pipe and is movable in the axial direction of the support pipe. The valve characteristic of the engine is changed by changing the oscillation phase difference of the output part with respect to the input part by moving the control shaft in the axial direction in a state where movement of the engine in the axial direction is restricted In the variable valve mechanism for an internal combustion engine, the support pipe includes a restricting portion that restricts movement of the input portion and the output portion to one side in the axial direction, and is capable of adjusting its position in the axial direction. I care It is provided as its gist the per.

  According to the above configuration, the support pipe includes the restriction portion that restricts the movement of the input portion and the output portion to one side in the axial direction. Therefore, the restriction portion causes the input portion and the output portion to move to one side in the axial direction. Movement can be regulated. In addition, since the support pipe is provided for each cylinder in a state where the position of the support pipe in the axial direction can be adjusted, the axial position of the input unit and the output unit can be adjusted by adjusting the axial position of the support pipe. it can. As a result, the position adjustment of the input unit and the output unit can be performed easily and with high accuracy. Since the support pipe is provided for each cylinder, the position adjustment of the input unit and output unit corresponding to a certain cylinder does not affect the position adjustment of the input unit and output unit corresponding to other cylinders. .

  Specifically, as described in claim 2, it is possible to adopt a configuration in which the restriction portion is formed of a ridge formed perpendicular to the axial direction of the support pipe. In this case, the configuration of the restricting portion can be simplified.

  The invention according to claim 3 is the cylinder head according to claim 1 or 2, wherein the support pipe is arranged perpendicularly to the axial direction of the support pipe and is abutted against the outer periphery of the support pipe. The gist of this is to be fixed to.

  According to the above configuration, the support pipe is fixed to the cylinder head by the bolt that is arranged perpendicular to the axial direction of the support pipe and contacts the outer periphery of the support pipe, so that the support pipe is fixed and the axial position is adjusted. Can be performed simultaneously.

  According to a fourth aspect of the present invention, the support pipe is arranged parallel to the axial direction of the support pipe and is adjusted in position according to the tightening amount of the bolt that contacts the flange. You can also

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the urging force is applied to the input portion and the output portion to one side in the axial direction in which movement is restricted by the restriction portion. The gist is to further include means.

  According to the above configuration, since the urging means urges the input unit and the output unit to one side in the axial direction in which the movement is restricted by the regulating unit, the input unit and the output unit to the other side where the movement is not regulated by the regulating unit. Movement is restricted. For this reason, the position adjustment of the input unit and the output unit can be performed easily and with high accuracy.

  An embodiment of a variable valve mechanism for an internal combustion engine according to the present invention will be described with reference to FIG. In addition, in this embodiment, about the structure same as the conventional variable valve mechanism, the description is abbreviate | omitted by attaching | subjecting the same code | symbol. Below, it demonstrates centering on difference with the conventional variable valve mechanism.

FIG. 1 is a partial cross-sectional view of the support pipe and its surrounding structure as viewed from the front.
As shown in FIG. 1, a plurality of bearings 8 (first bearing 8A and second bearing 8B) are provided on the upper side of the cylinder head 2 of the internal combustion engine. On the upper surfaces of these bearings 8, end portions of support pipes 22 (first support pipe 22 </ b> A, second support pipe 22 </ b> B, and third support pipe 22 </ b> C) provided for each cylinder are arranged. Cam caps 12 (first cam cap 12 </ b> A and second cam cap 12 </ b> B) are attached to the upper side of the bearing 8 so as to cover each end of the support pipe 22. A common control shaft 32 is inserted into the plurality of support pipes 22A, 22B, and 22C so as to be movable in the axial direction.

Here, the first support pipe 22 </ b> A will be described as a representative of the plurality of support pipes 22.
A slider gear 30 is fitted to the outer periphery of the first support pipe 22A so as to be movable in the axial direction. The slider gear 30 has an input portion 24 at the center in the axial direction, a first output portion 26 between the input portion 24 and the first bearing 8A, and a second output portion 28 between the input portion 24 and the second bearing 8B. Are meshed with each other.

  The first support pipe 22A is integrally formed with a disc-shaped flange 34A perpendicular to the axial direction thereof. The flange 34 </ b> A is disposed between the first bearing 8 </ b> A and the first output unit 26 in the axial direction and is in contact with the side surface of the first output unit 26. For this reason, the input part 24 and the output parts 26 and 28 are restricted from moving toward the first bearing 8A in the axial direction by the flange 34A. If the thickness of the flange 34A is too thin, there is a possibility that a problem in strength may occur when a large pressing force acts on the flange 34A from the first output portion 26. On the other hand, if the flange 34A is too thick, a large space is required when it is disposed between the bearing 8A and the first output portion 26, and the input portion 24 and the output portions 26 and 28 are connected to the first bearing. There is a risk of preventing the 8A side from approaching. For this reason, it is desirable to set the thickness of the collar 34A so as not to hinder the position adjustment of the input unit 24 and the output units 26 and 28 while satisfying the required strength.

  The length of the first support pipe 22A is formed larger than the distance between the first bearing 8A and the second bearing 8B. However, the length of the first support pipe 22A is set so that a predetermined gap V1 is secured between the first support pipe 22A and the second support pipe 22B adjacent thereto. Since the movement of the first support pipe 22A in the axial direction is allowed in the range of the gap V1, the axial position of the first support pipe 22A can be adjusted. If the gap V1 is made too large so that the position of the first support pipe 22A can be easily adjusted, that is, if the length of the first support pipe 22A is made too short, each end of the first support pipe 22A and the bearings 8A, 8B. The first contact pipe 22A may not be sufficiently supported by the bearings 8A and 8B. For this reason, it is desirable to set the length of the first support pipe 22A so that these ends are sufficiently supported by the bearings 8A and 8B while securing the gap V1 necessary for position adjustment.

  Bolt holes 14 </ b> A are formed in the cam cap 12 </ b> A in a direction perpendicular to the axial direction of the control shaft 32. A bolt 16 (bolt 16A) is screwed into the bolt hole 14A, and the first support pipe 22A is fixed by pressing the outer periphery of the support pipe 22A by the tip of the bolt 16A. As a result, the axial position of the first support pipe 22A is determined, and the movement of the first support pipe 22A in the axial direction is restricted.

  Between the second bearing 8B and the second output portion 28, the input portion 24 and the output portions 26, 28 are biased toward the first bearing 8A side, that is, one side in the axial direction in which movement is restricted by the flange 34A. A disc spring 18 as a biasing means is arranged. The disc spring 18 is configured by combining two frustoconical disc springs, and the second bearing 8B, the disc spring 18, and the second output portion in a state where the input portion 24 and the output portions 26 and 28 are assembled. 28 is set so that there is no gap between them.

According to the embodiment described above, the following effects can be obtained.
(1) Since the support pipe 22 includes a flange 34 as a restricting portion that restricts movement of the input portion 24 and the output portions 26 and 28 to one side in the axial direction, the input portion 24 and the output portion 26 are supported by the flange 34. , 28 can be restricted from moving in one axial direction. Further, since the support pipe 22 is provided for each cylinder in a state where the position of the support pipe 22 in the axial direction can be adjusted, the axial direction of the input unit 24 and the output units 26 and 28 is adjusted through the adjustment of the axial position of the support pipe 22. The position can be adjusted. As a result, the position adjustment of the input unit 24 and the output units 26 and 28 can be performed easily and with high accuracy. Since the support pipe 22 is provided for each cylinder, the position adjustment of the input unit 24 and the output units 26 and 28 corresponding to a certain cylinder is performed by adjusting the position of the input unit 24 and the output units 26 and 28 corresponding to other cylinders. It does not affect the position adjustment.

(2) Since the restricting portion is configured by the flange 34 formed perpendicular to the axial direction of the support pipe 22, the configuration of the restricting portion can be simplified.
(3) Since the support pipe 22 is fixed to the cam cap 12 (cylinder head 2) by the bolt 16 that is arranged perpendicular to the axial direction of the support pipe 22 and contacts the outer periphery of the support pipe 22, the support pipe 22 is fixed. And axial position adjustment can be performed simultaneously.

  (4) Since the disc spring 18 as an urging means urges the input portion 24 and the output portions 26 and 28 toward the first bearing 8A in the axial direction in which the movement is restricted by the flange 34, the movement is restricted by the flange 34. The movement of the input unit 24 and the output units 26 and 28 toward the second bearing 8B that is not performed is restricted. For this reason, the position adjustment of the input unit 24 and the output units 26 and 28 can be performed easily and with high accuracy.

  (5) When the support pipes 22A, 22B, and 22C are provided for each cylinder, the problem is where to set the boundaries between the adjacent support pipes 22A, 22B, and 22C. For example, if the boundary is set inside the slider gear 30, the slider gear 30 cannot be stably supported, and the operation of the variable valve mechanism may become unstable.

  In this regard, in this embodiment, the support pipe is divided inside the bearings 8A and 8B and the cam caps 12A and 12B, and each end of the support pipe 22 is supported by the cam cap 12. For this reason, in the present invention in which it is essential to provide the support pipe 22 for each cylinder, the slider gear 30 is reliably supported by the support pipe 22. Therefore, the operation of the variable valve mechanism does not become unstable in the present invention in which the support pipe 22 is provided for each cylinder.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, the disc spring 18 is used as the urging means. However, for example, a coil spring, a leaf spring, a spring washer, a wave washer or the like can be used as the urging means.

  In the above embodiment, the configuration is adopted in which the support pipe 22 is fixed to the cam cap 12 (cylinder head 2) by the bolt 16 that is arranged perpendicular to the axial direction of the support pipe 22 and contacts the outer periphery of the support pipe 22. The configuration for fixing the support pipe 22 to the cylinder head 2 is not limited to this. For example, the position of the support pipe 22 may be adjusted in accordance with the tightening amount of a bolt that is arranged in parallel with the axial direction of the support pipe 22 and abuts against the flange 34. Specifically, as shown in FIG. 2, a bolt hole 42A and a recess 44A are formed in the first bearing 40A in parallel with the axial direction of the support pipe 22A, and a bolt 46A is screwed into the bolt hole 42A. It is. Similarly, a bolt hole 52A and a recess 54A are formed in the first cam cap 50A in parallel with the axial direction of the support pipe 22A, and a bolt 56A is screwed into the bolt hole 52A. In this way, the bolt 46A is fixed to the bearing 40, and the bolt 56A is fixed to the cam cap 50A. The position of the support pipe 22A is adjusted according to the tightening amount of the bolts 46A and 56A by pressing the flange 34A toward the first output unit 26 at the tip ends of the bolts 46A and 56A.

  In the above embodiment, the configuration in which the support pipe 22 is fixed by the bolt 16 is adopted. However, after the positions of the input unit 24 and the output units 26 and 28 are adjusted, a support is provided by driving a pin into the support pipe 22 instead of the bolt 16. The pipe 22 may be fixed.

  In the above embodiment, the support pipe 22 including the circular flange 34 extending perpendicularly to the axial direction of the support pipe 22 is employed, but the shape of the support pipe is not limited to this. In short, it is provided with a restricting portion that restricts the movement of the input portion 24 and the output portions 26 and 28 to one side in the axial direction, and is provided for each cylinder in a state where its own position in the axial direction can be adjusted. Anything is acceptable.

The partial sectional view showing the support pipe concerning one embodiment of the present invention, and its peripheral structure. The fragmentary sectional view which shows the example of a change of a support pipe and its periphery structure. The top view which shows the mediation drive mechanism which comprises the conventional variable valve mechanism. Sectional drawing which shows the mediation drive mechanism which comprises the conventional variable valve mechanism.

Explanation of symbols

  2 ... cylinder head, 4 ... camshaft, 6 ... cam, 8, 40 ... bearing, 10 ... shim, 12, 50 ... cam cap, 14 ... bolt hole, 16 ... bolt, 20 ... mediation drive mechanism, 22, 122, 24 ... input unit, 24b ... roller, 24c, 24d ... input arm, 24e ... input gear, 26 ... first output unit, 26c ... first output arm, 26e ... first output gear, 28 ... second output unit, 28c ... second output arm, 28e ... second output gear, 30 ... slider gear, 32 ... control shaft, 34 ... 鍔, 42 ... bolt hole, 44 ... recess, 46 ... bolt, 52 ... bolt hole, 54 ... recess, 56 ... concave.

Claims (5)

A support pipe fixed to the cylinder head, an input portion that swings around the support pipe based on the rotation of the cam, and swings around the support pipe as the input portion swings to the engine valve An output unit that transmits driving force; and a control shaft that is disposed inside the support pipe and is movable in the axial direction of the support pipe, and the movement of the input unit and the output unit in the axial direction is restricted. In the variable valve mechanism for an internal combustion engine that changes the valve characteristic of the engine by changing the oscillation phase difference of the output part relative to the input part by moving the control shaft in the axial direction in the state where
The support pipe includes a restricting portion that restricts movement of the input portion and the output portion to one side in the axial direction, and is provided for each cylinder in a state where the position of the support pipe can be adjusted in the axial direction. A variable valve mechanism for an internal combustion engine.   The variable valve mechanism for an internal combustion engine according to claim 1, wherein the restricting portion is a rod formed perpendicular to the axial direction of the support pipe.   The variable valve mechanism for an internal combustion engine according to claim 1 or 2, wherein the support pipe is fixed to the cylinder head by a bolt that is arranged perpendicular to the axial direction of the support pipe and abuts against an outer periphery of the support pipe.   The variable valve mechanism for an internal combustion engine according to claim 2, wherein the position of the support pipe is adjusted in accordance with a tightening amount of a bolt that is disposed in parallel with the axial direction of the support pipe and abuts against the flange.   The variable valve mechanism for an internal combustion engine according to any one of claims 1 to 4, further comprising a biasing unit that biases the input unit and the output unit toward one side in the axial direction in which movement is regulated by the regulation unit.

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