WO2008041276A1

WO2008041276A1 - Valve gear for internal combustion engine

Info

Publication number: WO2008041276A1
Application number: PCT/JP2006/319460
Authority: WO
Inventors: Masayasu Nagado; Teruaki Ando
Original assignee: Nittan Valve Co., Ltd.
Priority date: 2006-09-29
Filing date: 2006-09-29
Publication date: 2008-04-10

Abstract

[PROBLEMS] A valve gear having a reduced number of parts and a reduced total weight. [MEANS FOR SOLVING PROBLEMS] A high lift cam (30) and low lift cams (32, 34) are integrated together and fixed to a camshaft (12). In a low lift mode, a piston (50) is placed in a region outside a region facing a slit (40), the high lift cam (30) is caused to pass the slit (40) when the camshaft (12) is rotated, and driving force from the camshaft (12) is transmitted to a valve stem (18) via the low lift cams (32, 34) and a rocker arm (20). In a high lift mode, the piston (50) is placed by hydraulic pressure into the region facing the slot (40), driving force from the camshaft (12) is transmitted to the valve stem (18) via the high lift cam (30), the piston (50), and the rocker arm (20).

Description

Specification

Valve operating device for internal combustion engine

Technical field

[0001] The present invention relates to a valve stem driving force from a cam shaft between a force moment fixed to a cam shaft that is rotationally driven in synchronization with the rotation of an internal combustion engine and a valve stem of an intake valve or an exhaust valve. The present invention relates to a valve operating device for an internal combustion engine in which a rocker arm that transmits to the inside is interposed. Background art

[0002] As a valve operating apparatus for an internal combustion engine, for example, three cams are integrally provided adjacent to each other on a camshaft, and are individually slidably contacted with each cam and pivotally supported on a rocker shaft. Two of them are brought into contact with a pair of intake valves or a pair of exhaust valves, respectively, to switch between a state in which all the rocker arms are integrally connected to each rocker arm and a state in which the relative angular displacement of each rocker arm is allowed. When the connection switching is made possible and the relative angular displacement of each mouth cap is allowed, the pair of intake valves or the pair of exhaust valves are individually opened and closed in response to the corresponding cams. When all the rocker arms are integrally connected, a pair of intake valves or a pair of exhaust valves are integrally opened and closed (Patent Document 1). reference).

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. Sho 62-121811 (Page 2 force is also Page 5, Figure 1 to Figure 5)

Disclosure of the invention

Problems to be solved by the invention

[0004] In the prior art, three rocker arms are provided corresponding to the three types of cams, guide holes communicating with each rocker arm are formed, and the guide holes are connected to the oil passages through the hydraulic chambers. In addition, when two pistons are reciprocally inserted into the guide holes to allow relative angular displacement of each rocker arm, two pistons that do not supply hydraulic pressure to the hydraulic chambers When it is housed in the guide holes of the two rocker arms and the mouth cams are individually swung, and all the rocker arms are connected together, hydraulic pressure is supplied to the hydraulic chambers. Place the pistons across the adjacent rocker arms, place them in the guide holes of each rocker arm, and connect each rocker arm to each other via each piston. Since it is connected and all rocker arms are swung together, the number of parts increases and the overall weight increases when connecting and releasing each rocker arm. Since each rocker arm is connected and released according to the position of the two pistons, high precision dimensions are required for the pistons and springs to position the two pistons. Geometric tolerances are required. This reduces the degree of freedom in engine design.

[0005] The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to reduce the number of parts and reduce the overall weight.

Means for solving the problem

In order to solve the above problems, a valve operating apparatus for an internal combustion engine according to claim 1 includes a cam fixed to a camshaft that is driven to rotate in synchronization with the rotation of the internal combustion engine, and an intake valve or an exhaust valve. In a valve operating apparatus for an internal combustion engine in which a rocker arm for transmitting a driving force from the cam shaft to the valve stem is interposed between the valve stem and a valve stem for applying a biasing force in a valve closing direction to the valve stem. A high lift cam and a low lift cam having different diameters are integrally formed, and the rocker arm includes a rocker arm body that is swingably disposed with a part of a rotation region of the high lift cam and the low lift cam as a swing region. A portion of the rocker arm body belonging to the rotation region of the high lift cam is formed with an idle slit that allows the high lift cam to pass therethrough, and the rocker arm A cylinder that includes a first space that partially belongs to the rotation region of the high lift cam and that faces the slit, and a second space that is adjacent to the first space and deviates from the rotation region force of the high lift cam. A chamber is formed, and a piston disposed in the first space or the second space is received in the cylinder chamber so as to reciprocate by receiving hydraulic pressure or elastic force, and the piston is placed in the cylinder chamber. When a hydraulic circuit that stakes against the elastic force and presses against the first space is connected, and the piston receives the hydraulic pressure of the hydraulic circuit force and is disposed in the first space, the piston and the piston When the rocker arm swings in a direction to apply driving force to the valve stem due to contact with the high lift cam, and the piston receives the elastic force and is disposed in the second space, the rocker arm The rocker arm oscillates in the direction in which a driving force is applied to the noble stem by contact between the main body and the low lift cam. [0007] (Operation) The high lift cam and the low lift cam are integrated and fixed on the camshaft. In the low lift mode, the piston is placed in a region where the region force that faces the slit of the rocker arm is released using the elastic force. When the camshaft rotates, the high lift cam is passed through the slit, and the driving force from the camshaft is transmitted to the noble stem via the low lift cam and the rocker arm. In the high lift mode, the hydraulic pressure from the hydraulic circuit is used. Since the piston is arranged in the area facing the slit of the rocker arm and the driving force from the camshaft is transmitted to the valve stem via the high lift cam, the piston and the rocker arm, it is less than the conventional valve gear. Can transmit the driving force corresponding to low lift mode or high lift mode to the valve stem. In addition, the overall weight of the apparatus can be reduced and the dimensional tolerances required for each component can be reduced, which can contribute to simplification of assembly work and reduction of manufacturing costs.

[0008] In the valve operating apparatus for an internal combustion engine according to claim 2, the cam fixed to the camshaft that is driven to rotate in synchronization with the rotation of the internal combustion engine, and the intake valve or the exhaust valve are attached in the valve closing direction. In a valve operating apparatus for an internal combustion engine in which a rocker arm for transmitting a driving force from the camshaft to the valve stem is interposed between a valve stem for applying a force, the cam has a high diameter and a different diameter. A lift cam and a low lift cam are integrally formed, and the rocker arm includes a rocker arm body that is swingably disposed with a part of a rotation region of the high lift cam and the low lift cam as a rocking region, and the rocker arm A portion of the main body that belongs to the rotation region of the high lift cam is formed with an idle slit through which the high lift cam can pass, and the rocker arm main body includes the high swing cam. A cylinder chamber including a first space partly belonging to the rotation region of the cam and facing the slit and a second space adjacent to the first space and deviating from the rotation region of the high lift cam; A piston disposed in the first space or the second space is accommodated in the cylinder chamber so as to be able to reciprocate in accordance with hydraulic pressure, and the cylinder chamber is configured to press the piston against the first space. And a second hydraulic circuit that presses the piston against the second space, and the piston is disposed in the first space by the hydraulic pressure from the first hydraulic circuit. Due to the contact between the piston and the high lift cam, the rocker arm swings in a direction to apply a driving force to the valve stem, and the piston is moved from the second hydraulic circuit. When disposed in the second space by hydraulic pressure, the rocker arm swings in a direction in which a driving force is applied to the valve stem by contact between the rocker arm main body and the low lift cam. .

[0009] (Operation) The high lift cam and the low lift cam are integrated and fixed on the camshaft, and in the low lift mode, the area cover that faces the slit of the rocker arm using the hydraulic pressure from the second hydraulic circuit. When the camshaft rotates, the high lift cam passes through the slit and the driving force from the camshaft is transmitted to the valve stem via the low lift cam and the rocker arm. Because the piston is located in the area facing the slit of the rocker arm using the hydraulic pressure of the first hydraulic circuit force, the driving force from the camshaft is transmitted to the vano rev stem via the high lift cam, piston and rocker arm. The drive force corresponding to the low lift mode or high lift mode is reduced with fewer components than conventional valve gears. Can be transmitted to the stem, and the weight of the entire device can be reduced, and the dimensional tolerances required for each component can be reduced, contributing to simplification of assembly work and reduction of manufacturing costs. it can.

[0010] In the valve operating apparatus for an internal combustion engine according to claim 3, in the valve operating apparatus for the internal combustion engine according to claim 1 or 2, the rocker arm is swingably supported by a rocker shaft, and The point at which force from the lift cam or the low lift cam is applied is the point of application, the point of applying driving force to the valve stem is the point of application, and the point of connection with the rocker shaft is the point of support. The structure is located between the force point and the action point.

(Operation) When the rocker arm receives a high lift cam force or a low lift cam force, the rocker arm swings around the rocker arm as a fulcrum and applies a driving force to the valve stem. By placing the fulcrum, which is the connection point with the rocker arm, between the force point and the action point, the high lift cam and the low lift cam can be placed on the same side as the valve stem with respect to the rocker arm. Reduce the height.

[0012] In the valve operating apparatus for an internal combustion engine according to claim 4, the valve operating apparatus for an internal combustion engine according to any one of claim 1, 2 or 3, wherein the cylinder chamber is cylindrical. The piston is formed of a cylindrical body. (Operation) Since the piston is formed as a cylindrical body, even if the outer diameter of the piston is small, the high lift cam can be moved with a high lift amount, and the rocker arm can be configured compactly. Furthermore, since the cylindrical piston has a degree of freedom in the direction of rotation, when the high lift cam presses the piston, the torque of the high lift cam can be reduced, and wear due to friction between the high lift cam and the piston should be reduced. Can do.

The invention's effect

As is apparent from the above description, according to the valve operating apparatus for an internal combustion engine according to claim 1, the number of parts can be reduced, the overall weight can be reduced, and the assembly work can be simplified. It is also possible to contribute to the reduction of manufacturing costs.

[0015] According to the valve operating apparatus for an internal combustion engine according to claim 2, the number of parts can be reduced, the overall weight can be reduced, and the assembly work can be simplified and the manufacturing cost can be reduced. It becomes pretty.

[0016] According to claim 3, the overall height of the apparatus can be reduced.

[0017] According to claim 4, the rocker arm can be configured compactly and wear due to friction between the high lift cam and the piston can be reduced.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a valve operating apparatus for an internal combustion engine showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing the relationship between an intake valve and a valve stem arranged in a cylinder head, and FIG. FIG. 5 is a view for explaining the operation in the low lift mode of the valve gear for the internal combustion engine according to the first embodiment of the present invention, wherein (a) is a front view including a cross-section of the main part, and (b) FIG. 4A is a cross-sectional view taken along line AA in FIG. 4A, FIG. 4C is a cross-sectional view taken along line BB in FIG. 4A, and FIG. 4 is a valve gear for an internal combustion engine according to the first embodiment of the present invention. It is a figure for demonstrating the operation | movement in high lift mode, (a) is a top view, (b) is sectional drawing in alignment with the AA line of (a), (c) is (b) FIG. 5B is a cross-sectional view taken along the line B-B, FIG. 5D is a cross-sectional view taken along the line CC in FIG. 5B, and FIG. 5 is an exploded perspective view of the valve gear for the internal combustion engine showing the second embodiment of the present invention. FIG. 6 shows a valve operating of the internal combustion engine according to the second embodiment of the present invention. (A) is a front view including the main part cross-section, (b) is a cross-sectional view taken along line A—A in (a), c) is a cross-sectional view taken along line BB in (a), and FIG. FIG. 4 is a view for explaining the operation in the high lift mode of the valve gear of the internal combustion engine according to the second embodiment, in which (a) is a plan view and (b) is an AA line of (a). (C) is a cross-sectional view taken along the line BB in (b), (d) is a cross-sectional view taken along the line CC in (b), and FIG. 8 is a third embodiment of the present invention. FIG. 9 is an exploded perspective view of the valve operating apparatus for an internal combustion engine showing FIG. 9. FIG. 9 is a view for explaining the operation in the low lift mode of the valve operating apparatus for the internal combustion engine according to the third embodiment of the present invention. ) Is a front view including the main section, (b) is a cross-sectional view taken along line AA in (a), (c) is a cross-sectional view taken along line BB in (a), and FIG. FIG. 4 is a view for explaining the operation in the high lift mode of the valve gear of the internal combustion engine according to the third embodiment of the present invention, in which (a) is a plan view and (b) is a view of (a). A— A cross-sectional view along the line A, (c) is a cross-sectional view along the line B--B in (b), (d) FIG. 11 is an exploded perspective view of the valve gear for an internal combustion engine showing the fourth embodiment of the present invention, and FIG. 12 is an internal combustion engine according to the fourth embodiment of the present invention. It is a figure for demonstrating the operation | movement in the low lift mode of the valve gear of an engine, (a) is a top view, (b) is sectional drawing in alignment with the AA line of (a), (c) (B) is a cross-sectional view along line B-B, (d) is a cross-sectional view along line C-C in (b), (e) is a cross-sectional view along line D-D in (b) FIGS. 13A and 13B are views for explaining the operation in the high lift mode of the valve operating apparatus for the internal combustion engine according to the fourth embodiment of the present invention. FIG. 13A is a plan view, and FIG. (a) is a cross-sectional view along line A-A, (c) is a cross-sectional view along line B-B in (b), (d) is a cross-sectional view along line CC in (b), (e) is It is sectional drawing which follows the DD line of (b).

1 to 4, a valve operating apparatus 10 for an internal combustion engine includes a cam 14 fixed to a camshaft 12 that is driven to rotate in synchronization with the rotation of an internal combustion engine, for example, an automobile engine, and an intake valve (or A rocker arm 20 that is connected to the exhaust valve 16 and transmits the driving force from the camshaft 12 to the valve stem 18 is provided between the valve stem 18 and the valve stem 18 for applying an urging force in the valve closing direction to the intake valve 16. Interposed. The intake valve 16 is arranged so as to open and close an intake port 24 formed in a cylinder head 22 of an automobile engine, and a part of the norb stem 18 is housed in a cylinder bore 28 together with a compression coil spring 26. ing. One end of the compression coil spring 26 is supported by the valve stem 18 and the other end is supported by the cylinder bore 28 so as to apply a closing force to the intake valve 16 via the valve stem 18. RU [0020] In the cam 14, a high lift cam 30 and low lift cams 32, 34 are integrated and fixed to the outer peripheral surface of the cam shaft 12. The high lift cam 30 is arranged between the low lift cam 32 and the low lift cam 34 as a cam having a larger diameter than the low lift cams 32 and 34 having the same shape, that is, a cam having a larger lift amount than the low lift cams 32 and 34. As the camshaft 12 rotates, it rotates with the low lift cams 32 and 34.

[0021] On the lower side of the high lift cam 30 and the low lift cams 32 and 34, a rocker arm 20 having a part of the rotation region of the high lift cam 30 and the low lift cams 32 and 34 as a swing region is swingable on the rocker shaft 36. It is connected.

The rocker arm 20 is provided with a rocker arm main body 38 partially disposed in the rotation regions of the high lift cam 30 and the low lift cams 32 and 34. A portion of the rocker arm body 38 that belongs to the rotation region of the high lift force 30 can pass the high lift cam 30 and is formed with a slit 40 for idling that is wider than the high lift force 30. Arc portions 42 and 44 are formed on both sides of the slit 40 at a portion belonging to the rotation region of the low lift cams 32 and 34 and serving as a force point to which the force from the low lift cams 32 and 34 is applied. The rocker arm main body 38 is formed with circular holes 46, 48. The rocker shaft 36 is passed through the hole 46, and the piston 50 is accommodated in the hole 48. One end of the hole 48 is closed by a lid 60 of the lock 58, and a cylindrical cylinder chamber 64 defined by the rocker arm body 38 and the lid 60 is formed in the hole 48, and a cylinder is formed in the cylinder chamber 64. Shaped piston 50 is reciprocally inserted

[0023] A part of the cylinder chamber 64 belongs to the rotation region of the high lift cam 30, and the first space 64a facing the slit 40 and the rotation region force of the high lift cam 30 are also separated from the first space 64a. The second space 64b is included. An oil passage 66 formed in the rocker arm body 38 is connected to the cylinder chamber 64 as an element of the hydraulic circuit. The oil passage 66 is connected to the control valve via the oil passage 68 in the rocker shaft 36. (Not shown) and a hydraulic power source (not shown). Adjacent to the cylinder chamber 64, an auxiliary cylinder chamber 72 defined by a rocker arm main body 38, a ring 62 of the lock 58 and a partition wall 70 in the rocker arm main body 38 is formed in the hole 48. The auxiliary cylinder chamber 72 contains a plunger 52, a compression coil spring 54, and a plug 56. The axial end of the plug 56 has a lock 58. Supported by ring 62. The plunger 52 is formed in a bottomed cylindrical shape and is slidably disposed along the auxiliary cylinder chamber 72. The plunger 52 is disposed between the plunger 52 and the plug 56 so as to be stretchable. Further, the elastic force of the compression coil spring 54 is biased in the direction away from the plug 56. In other words, the plunger 52 is arranged so that its distal end abuts against the axial end of the piston 50 under the elastic force from the compression coil spring 54.

[0024] When the hydraulic pressure from the hydraulic circuit does not act on the piston 50 in the cylinder chamber 64, only the elastic force of the compression coil spring 54 acts on the piston 50 from the plunger 52, and the piston 50 In the second space 64b. That is, when the low lift mode is selected, as shown in FIGS. 3 (a) to (c), the piston 50 moves backward from the first space 64a and is disposed in the second space 64b. At this time, when the camshaft 12 rotates, the high lift cam 30 and the low lift cams 32 and 34 rotate.

[0025] In this case, the high lift cam 30 is a force that passes through the slit 40 of the rocker arm 20 without coming into contact with the rocker arm 20. The low lift cams 32 and 34 move down the circular portions 42 and 44 of the rocker arm 20 with a low lift amount. Press on. When the arc-shaped portions 42 and 44 of the rocker arm 20 are pressed downward, the rocker arm 20 gives a driving force to the valve stem 18 with the rocker shaft 36 as a fulcrum by the contact between the rocker arm body 38 and the low lift cams 32 and 34. The tip 74 of the rocker arm 20 acts as an action point to press the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted to the valve stem 18 as a driving force with a low lift amount, and the intake valve 16 stakes against the elastic force of the compression coil spring 26 to open the intake port. 2 4 is opened.

[0026] Thereafter, as the camshaft 12 rotates, the rocker arm body 38 and the low lift cams 32, 34 are in sliding contact, and the rocker arm 20 applies a driving force to the valve stem 18 with the rocker shaft 36 as a fulcrum. The intake valve 16 is closed in accordance with the elastic force of the compression coil spring 26, and the intake port 24 is closed.

[0027] In this case, the rocker arm 20 has a point where a force from the high lift cam 30 or the low lift cams 32, 34 is applied as a force point, and a point where a driving force is applied to the valve stem 18 as an action point. When the connection point is a fulcrum, the middle of the fulcrum and the action point functions as a force point It is configured as follows.

On the other hand, when the high lift mode is selected, as shown in FIGS. 4 (a) to (d), the piston 50 in the cylinder chamber 64 has an oil pressure in addition to the elastic force of the compression coil spring 54. The hydraulic pressure from the circuit acts, and the piston 50 is piled on the elastic force of the compression coil spring 54 and moves from the second space 64b to the first space 64a, and is disposed in the first space 64a, and is slit. A part of 40 is exposed. At this time, when the camshaft 12 rotates, the high lift cam 30 and the low lift forces 32 and 34 rotate. In this case, the high lift cam 30 having a diameter larger than that of the low lift cams 32 and 34 is a force for pressing the piston 50 exposed from the slit 40 downward with a high lift amount. The low lift cams 32 and 34 are the arcuate portions 42 and 44 of the rocker arm 20. Rotates without touching. When the piston 50 is pressed downward, the piston 50 and the high lift cam 30 abut on the rocker arm 20 force rocker shaft 36 as a fulcrum and swing in a direction to apply a driving force to the valve stem 18. The tip 74 acts as a point of action to press the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted as a driving force with a high lift amount to the knob stem 18, and the intake valve 16 is piled on the elastic force of the compression coil spring 26 to open the intake port 24. Is opened.

[0029] Thereafter, as the camshaft 12 rotates, the piston 50 and the high lift cam 30 are in sliding contact or rolling while the rocker arm 20 applies driving force to the valve stem 18 with the rocker shaft 36 as a fulcrum. Swings in the opposite direction, the intake valve 16 is closed according to the inertial force of the compression coil spring 26, and the intake port 24 is closed.

[0030] According to the present embodiment, the high lift cam 30 and the low lift cams 32, 34 are integrated and fixed to the camshaft 12, and in the low lift mode, the elastic force of the compression coil spring 54 is used to lock the cam. The piston 50 is arranged in a region outside the region facing the slit 40 of the force arm 20, and when the cam shaft 12 rotates, the high lift cam 30 is passed through the slit 40 and the driving force from the cam shaft 12 is reduced to the low lift cam 32, 34. In the high lift mode, using the hydraulic pressure from the hydraulic circuit, the piston 50 is placed in the area facing the slit 40 of the rocker arm 20 and from the camshaft 12. The driving force is transmitted to the valve stem 18 via the high lift cam 30, piston 50 and rocker arm 20. Drive corresponding to the mode or the high-lift mode Power can be transmitted to the valve stem 18, and the overall weight of the device can be reduced, and the dimensional tolerances required for each component can be reduced, simplifying assembly work and reducing manufacturing costs. Can contribute.

[0031] Next, a second embodiment of the present invention will be described with reference to Figs. In this embodiment, instead of the rocker shaft 36, a pivot 76 is used as a fulcrum, and instead of the rocker arm 20, a rocker arm 20A having a base 78 having a shape and structure different from that of the rocker arm 20 is used. Other configurations are the same as those of the first embodiment.

[0032] The pivot 76 is formed by integrally forming a substantially cylindrical main body 80 and a support portion 82 having a smaller diameter than the main body 80. The main body 80 and the support portion 82 are formed as elements of a hydraulic circuit. The oil passage 84 is formed so that the side force of the main body 80 extends to the upper side of the support portion 82. The support portion 82 has a hemispherical upper portion as a fulcrum. The base end portion 78 of the rocker arm 20A is formed in a spherical shape on the bottom side and can be fitted to the support portion 82 of the pivot 76. The base end portion 78 includes the oil passage 84 and the cylinder of the pivot 76. An oil passage 86 connecting the chamber 64 is formed.

In this embodiment, when the low lift mode is selected, as shown in FIGS. 6 (a) to (c), the piston 50 is disposed in the second space 64b. At this time, the camshaft When 12 rotates, the high lift cam 30 and the low lift cams 32 and 34 rotate. In this case, the high lift cam 30 passes through the slit 40 of the rocker arm 20A without coming into contact with the rocker arm 20A, but the low lift cams 32 and 34 push the arcuate portions 42 and 44 of the rocker arm 20A downward with a low lift amount. To do. When the arc-shaped portions 42 and 44 of the rocker arm 20A are pressed downward, the rocker arm 20A applies driving force to the valve stem 18 with the pivot 76 as a fulcrum by the contact between the rocker arm body 38A and the low lift cams 32 and 34. And the tip 74 of the rocker arm 20A acts as an action point to press the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted to the valve stem 18 as a driving force with a low lift amount, the intake valve 16 opens against the elastic force of the compression coil spring 26, and the intake port 24 opens. It is.

[0034] Thereafter, as the camshaft 12 rotates, the rocker arm body 38A and the low lift cams 32, 34 are in sliding contact, and the rocker arm 20A applies driving force to the valve stem 18 with the pivot 76 as a fulcrum. Oscillates in the opposite direction, and the intake valve 16 The valve is closed according to the elastic force, and the intake port 24 is closed.

On the other hand, when the high lift mode is selected, as shown in FIGS. 7 (a) to (d), the piston 50 receives the oil pressure from the oil passages 84 and 86, and the elasticity of the compression coil spring 54. It is piled into force and moved from the second space 64b to the first space 64a and is disposed in the first space 64a, and a part thereof is exposed from the slit 40. At this time, when the camshaft 12 rotates, the high lift cam 30 and the low lift cams 32 and 34 rotate. In this case, the high lift cam 30 having a diameter larger than that of the low lift cams 32 and 34 presses the piston 50 exposed from the slit 40 downward with a high lift amount, but the low lift cams 32 and 34 are the arcuate portions 42 and 32 of the rocker arm 20A. Rotates without touching 44. When the piston 50 is pressed downward, the rocker arm 20A swings around the pivot 76 in the direction to apply the driving force to the valve stem 18 due to the contact between the piston 50 and the high lift cam 30, and the rocker arm 20A The tip 74 acts as a point of action to press the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted to the valve stem 18 as a driving force with a high lift amount, the intake valve 16 opens against the elastic force of the compression coil spring 26, and the intake port 24 opens. It is.

Thereafter, as the camshaft 12 rotates, the piston 50 and the high lift cam 30 are in sliding contact or rolling while the rocker arm 20A applies the driving force to the valve stem 18 with the pivot 76 as a fulcrum. Swinging in the opposite direction causes the intake valve 16 to close according to the elastic force of the compression coil spring 26, and the intake port 24 is closed.

[0037] According to the present embodiment, the high lift cam 30 and the low lift cams 32, 34 are integrated and fixed to the camshaft 12, and in the low lift mode, the elastic force of the compression coil spring 54 is used to lock the cam. The piston 50 is arranged in a region outside the region facing the slit 40 of the force arm 20A, and when the force shaft 12 rotates, the high lift cam 30 is passed through the slit 40 and the driving force from the cam shaft 12 is reduced to the low lift cam 32, 34 and the rocker arm 20A through the rocker arm 20A, and in the high-lift mode, the hydraulic pressure from the hydraulic circuit is used to place the piston 50 in the region facing the slit 40 of the rocker arm 20A and from the camshaft 12. Is transmitted to the valve stem 18 through the high lift cam 30, the piston 50 and the rocker arm 20A. The driving force corresponding to the lift mode or the high lift mode can be transmitted to the valve stem 18, and the weight of the entire device can be reduced. It is possible to reduce the dimensional tolerance required for each component, and to contribute to simplification of assembly work and reduction of manufacturing cost.

[0038] Next, a third embodiment of the present invention will be described with reference to Figs. In this embodiment, instead of the rocker arm 20, the rocker arm 20 uses the mouth arm 20 B in which the positions of the hole 46 and the hole 48 are opposite to each other, and the cam 14 is placed below the rocker arm 20 B. The rocker shaft 36 is used as a fulcrum, and other configurations are the same as those of the first embodiment.

That is, the rocker arm 20B is formed between the hole 46 force front end portion 74 and the base end portion 78, the hole 48 is formed in the base end portion 78, and the rocker shaft 36 inserted into the hole 46 is connected to the rocker arm 20B. It swings as a fulcrum. The force from the lower lift cams 32 and 34 disposed below the mouth cam 20B acts on the arcuate portions 42 and 44 of the rocker arm 20B from below, and the slit 40 force is exposed to the piston 50 exposed to the rocker arm 20B. The force from the high lift cam 30 disposed below acts as a downward force.

In the present embodiment, when the low lift mode is selected, as shown in FIGS. 9 (a) to (c), the piston 50 is disposed in the second space 64b. At this time, the camshaft When 12 rotates, the high lift cam 30 and the low lift cams 32 and 34 rotate. In this case, the high lift cam 30 passes through the slit 40 of the rocker arm 20B without contacting the rocker arm 20B, but the low lift cams 32 and 34 push the arcuate portions 42 and 44 of the rocker arm 20B upward with a low lift amount. Press. When the arc-shaped portions 42 and 44 of the rocker arm 20B are pressed upward, the rocker arm 20B is driven to the valve stem 18 with the rocker shaft 36 as a fulcrum by the contact between the rocker arm body 38B and the low lift cams 32 and 34. The tip end portion 74 of the rocker arm 20B acts as an action point and presses the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted to the valve stem 18 as a driving force with a low lift amount, and the intake valve 16 is opened against the elastic force of the compression coil spring 26. Is opened.

[0041] Thereafter, as the camshaft 12 rotates, the rocker arm body 38B and the low lift cams 32, 34 are in sliding contact with each other, and the rocker arm 20B applies a driving force to the valve stem 18 with the rocker shaft 36 as a fulcrum. The intake valve 16 swings in the direction opposite to the direction, the valve closing operation is performed according to the elastic force of the compression coil spring 26, and the intake port 24 is closed. On the other hand, when the high lift mode is selected, as shown in FIGS. 10 (a) to (d), the piston 50 receives the hydraulic pressure from the oil passages 66 and 68, and the compression coil spring 54 It is piled by the elastic force and moved from the second space 64b to the first space 64a, and is disposed in the first space 64a, and a part thereof is exposed from the slit 40. At this time, when the camshaft 12 rotates, the high lift cam 30 and the low lift cams 32 and 34 rotate. In this case, the high lift cam 30 having a diameter larger than that of the low lift cams 32 and 34 presses the piston 50 exposed from the slit 40 upward with a high lift amount, but the low lift cams 32 and 34 are the arcuate portions 42 and 32 of the rocker arm 20B. Rotates without touching 44. When the piston 50 is pressed upward, the rocker arm 20B swings about the rocker shaft 36 as a fulcrum in the direction in which the driving force is applied to the valve stem 18 due to the contact between the piston 50 and the high lift cam 30, and the rocker arm 20B The tip 74 of the valve acts as an action point and presses the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted to the valve stem 18 as a driving force with a high lift amount, the intake valve 16 opens against the elastic force of the compression coil spring 26, and the intake port 24 be opened.

[0043] Thereafter, as the camshaft 12 rotates, the piston 50 and the high lift cam 30 are in sliding contact or rolling, and the rocker arm 20B applies a driving force to the valve stem 18 with the rocker shaft 36 as a fulcrum. Swings in the opposite direction, the intake valve 16 is closed according to the elastic force of the compression coil spring 26, and the intake port 24 is closed.

According to the present embodiment, the high lift cam 30 and the low lift cams 32 and 34 are integrated and fixed to the camshaft 12, and in the low lift mode, the elastic force of the compression coil spring 54 is used to lock the cam. The piston 50 is arranged in a region outside the region facing the slit 40 of the force arm 20B, and when the force shaft 12 rotates, the high lift cam 30 is passed through the slit 40 and the drive force from the cam shaft 12 is reduced to the low lift cam 32, 34 and the rocker arm 20B to the valve stem 18, and in the high-lift mode, the hydraulic pressure from the hydraulic circuit is used to place the piston 50 in the region facing the slit 40 of the rocker arm 20B. Is transmitted to the valve stem 18 through the high lift cam 30, the piston 50 and the rocker arm 20B. The driving force corresponding to the lift mode or the high lift mode can be transmitted to the valve stem 18, the overall weight of the device can be reduced, and the dimensional tolerance required for each component can be reduced. work This can contribute to simplification and reduction of manufacturing costs.

[0045] Further, according to the present embodiment, the point where the force of the high lift cam 30 or the low lift cam 32, 34 is applied is the power point, the connection point with the rocker shaft 36 is the fulcrum, and the driving force is applied to the valve stem 18. When the point to be applied is the point of application, the fulcrum is located between the force point and the point of action, so the high lift cam 30 and the low lift cams 32, 34 are on the same side as the valve stem 18 with respect to the rocker arm 20B. It can arrange | position and can reduce the height of the whole apparatus.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 11 to 13. In this embodiment, a rocker arm 20C is used instead of the rocker arm 20, two oil passages are provided on the rocker shaft 36, and the position of the piston 50 in the low lift mode and the high lift mode is switched by hydraulic pressure. The other configuration is the same as that of the first embodiment.

[0047] Specifically, the rocker arm 20C includes a rocker arm main body 38C that is partially different in structure from the rocker arm main body 38, and a disk-shaped lid 88 and a rocker arm main body are provided in the hole 48 of the rocker arm main body 38C. A cylinder chamber 64 defined by 38C and an auxiliary cylinder chamber 72 defined by a bottomed cylindrical plug 90 and a rocker arm body 38C are formed. A cylindrical piston 50 is slidably inserted into the cylinder chamber 64, and a bottomed cylindrical plunger 92 is slidably inserted into the auxiliary cylinder chamber 72. The rocker arm body 38 C has an oil passage 66 connecting the cylinder chamber 64 and the oil passage 68 of the rocker shaft 36, and an oil passage 96 connecting the auxiliary cylinder chamber 72 and the oil passage 94 of the rocker shaft 36. Is formed. In addition, a hole (not shown) which is an element of the oil passage 96 is formed on the side surface of the plug 90, and the oil passage 68 and the oil passage 94 of the rocker shaft 36 are mutually connected with a partition wall 98 therebetween. Isolated on

In this embodiment, when the low lift mode is selected, the hydraulic pressure from the oil passage 94 is supplied to the auxiliary cylinder chamber 72 via the oil passage 96 as shown in FIGS. 12 (a) to (e). Then, the plunger 92 slides from the auxiliary cylinder chamber 72 toward the cylinder chamber 64, and the piston 50 moves from the first space 64a into the second space 64b as the plunger 92 slides. At this time, when the camshaft 12 rotates, the high lift cam 30 and the low lift cams 32 and 34 rotate. In this case, the high lift cam 30 is a force that passes through the slit 40 of the rocker arm 20C without coming into contact with the rocker arm 20C. The low lift cams 32 and 34 have a low lift amount and the circle of the rocker arm 20C. Press the arcuate parts 42 and 44 downward. When the arcuate portions 42 and 44 of the rocker arm 20C are pressed downward, the rocker arm 20C exerts a driving force on the valve stem 18 with the rocker shaft 36 as a fulcrum by the contact between the rocker arm body 38C and the low lift cams 32 and 34. It rocks in the direction of application, and the tip 74 of the rocker arm 20C acts as an action point to press the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted to the valve stem 18 as a driving force with a low lift amount, and the intake valve 16 stakes against the elastic force of the compression coil spring 26 to open the valve, and the intake port 24 be opened.

[0049] Thereafter, as the camshaft 12 rotates, the rocker arm body 38C and the low lift cams 32, 3 4 are in sliding contact, and the rocker arm 20C applies a driving force to the valve stem 18 with the rocker shaft 36 as a fulcrum. The intake valve 16 swings in the direction opposite to the direction, the valve closing operation is performed according to the elastic force of the compression coil spring 26, and the intake port 24 is closed.

On the other hand, when the high lift mode is selected, as shown in FIGS. 13 (a) to (e), the hydraulic pressure from the oil passage 68 is supplied to the cylinder chamber 64 via the oil passage 66, and the piston is 50 moves from the second space 64b into the first space 64a, and the plunger 92 moves from the cylinder chamber 64 toward the auxiliary cylinder chamber 72 as the piston 50 moves. The piston 50 receives the hydraulic pressure from the oil passages 68 and 66, is disposed in the first space 64a, and a part of the piston 50 is exposed from the slit 40. At this time, when the camshaft 12 rotates, the high lift cam 30 and the low lift cams 32 and 34 rotate. In this case, the high lift cam 30 whose diameter is larger than that of the low lift cams 32 and 34 is the force that pushes the piston 50 exposed from the slit 40 downward with a high lift amount. The low lift force 32 and 34 are the arcuate portions of the rocker arm 20C. Rotates without touching 42, 44. When the piston 50 is pressed downward, the rocker arm 20C swings in a direction to apply a driving force to the valve stem 18 with the rocker shaft 36 as a fulcrum by the contact between the piston 50 and the high lift cam 30, and the rocker arm 20C The tip 74 of the valve acts as a point of action to press the valve stem 18. As a result, the driving force from the camshaft 12 is transmitted to the valve stem 18 as a driving force of a high lift amount, and the intake valve 16 is piled up by the elastic force of the compression coil spring 26 to open the intake port 24. be opened.

[0051] After that, as the camshaft 12 rotates, the piston 50 and the high lift cam 30 are in sliding contact or rolling, and the rocker arm 20C moves to the valve stem 18 with the rocker shaft 36 as a fulcrum. It swings in the direction opposite to the direction in which the driving force is applied, the intake valve 16 is closed according to the elastic force of the compression coil spring 26, and the intake port 24 is closed.

[0052] According to the present embodiment, the high lift cam 30 and the low lift cams 32, 34 are integrated and fixed to the camshaft 12, and in the low lift mode, the second hydraulic circuit (oil passages 94, 96) The piston 50 is placed in an area where the area force that faces the slit 40 of the rocker arm 20C is also removed using the hydraulic pressure of the rocker arm 20C, and when the camshaft 12 rotates, the high lift cam 30 is passed through the slit 40 and from the force shaft 12 Is transmitted to the valve stem 18 via the low lift cams 32 and 34 and the rocker arm 20C, and in the high lift mode, the hydraulic pressure from the first hydraulic circuit (oil passages 66 and 68) is used to generate the rocker arm 20C. Since the piston 50 is arranged in the area facing the slit 40 of the shaft, the driving force from the force shaft 12 is transmitted to the valve stem 18 via the high lift cam 30, the piston 50 and the rocker arm 20C. The driving force corresponding to the low lift mode or the high lift mode can be transmitted to the valve stem 18 with fewer components than the conventional valve gear, and the overall weight of the device is reduced and required for each component. Dimensional tolerance can be relaxed, which can contribute to simplification of assembly work and reduction of manufacturing cost.

[0053] In this embodiment, the rocker arm 20C has a force applied from the high lift cam 30 or the low lift cams 32, 34 as a power point, a connection point with the rocker shaft 36 as a fulcrum, and a driving force applied to the valve stem 18. The point where the point is given is used as the point of action, and the force point is located between the fulcrum and the point of action, but the point between the force point and the point of action is used as the fulcrum. Alternatively, a support point by the pivot 76 can be used as a fulcrum, and a force point between the fulcrum and the action point can be used.

[0054] Further, according to each of the embodiments, the weight of the entire component can be reduced as the number of parts is reduced, and it is unnecessary to support the high lift cam 30 with the spring member in the low lift mode. Therefore, it is not necessary to limit the number of rotations in the low lift mode in consideration of the spring force of the spring member supporting the high lift cam 30, and to consider the sag of the spring member. The degree can be increased.

[0055] Further, according to each of the embodiments, since the piston 50 is formed in a cylindrical shape as a cylindrical body, the high lift cam 30 can be moved with a high lift amount even if the outer diameter of the piston 50 is small. The rocker arm 20-20C can be configured compactly. Further, since the cylindrical piston 50 has a degree of freedom in the rotation direction, when the high lift cam 30 presses the piston 50, the torque of the high lift cam 30 can be reduced, and the friction between the high lift cam 30 and the piston 50 can be reduced. It is possible to reduce wear due to the above. In addition, since the cylindrical piston 50 is slidably inserted into the cylindrical cylinder chamber 64, the clearance between the piston 50 and the cylinder chamber 64 can be easily adjusted when ensuring the hydraulic pressure, and the piston It is possible to suppress a decrease in hydraulic pressure due to friction between 50 and the cylinder chamber 64.

Brief Description of Drawings

1 is an exploded perspective view of a valve gear for an internal combustion engine showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the relationship between an intake valve and a valve stem arranged in a cylinder head.

FIG. 3 is a view for explaining the operation in the low lift mode of the valve gear for the internal combustion engine according to the first embodiment of the present invention, wherein (a) is a front view including a cross section of the main part; ) Is a cross-sectional view taken along line AA in (a), and (c) is a cross-sectional view taken along line BB in (a).

FIG. 4 is a view for explaining the operation in the high lift mode of the valve gear of the internal combustion engine according to the first embodiment of the present invention, where (a) is a plan view, and (b) is (a (C) is a cross-sectional view taken along the line BB in (b), and (d) is a cross-sectional view taken along the line C-C in (b).

FIG. 5 is an exploded perspective view of a valve gear for an internal combustion engine showing a second embodiment of the present invention.

FIG. 6 is a view for explaining the operation in the low lift mode of the valve operating apparatus for the internal combustion engine according to the second embodiment of the present invention, wherein (a) is a front view including a cross section of the main part; ) Is a cross-sectional view taken along line AA in (a), and (c) is a cross-sectional view taken along line BB in (a).

FIG. 7 is a view for explaining the operation in the high lift mode of the valve gear of the internal combustion engine according to the second embodiment of the present invention, where (a) is a plan view and (b) is (a (C) is a cross-sectional view taken along the line BB in (b), and (d) is a cross-sectional view taken along the line C-C in (b).

FIG. 8 is an exploded perspective view of a valve gear for an internal combustion engine showing a third embodiment of the present invention.

FIG. 9 is a view for explaining the operation in the low lift mode of the valve operating apparatus for the internal combustion engine according to the third embodiment of the present invention, wherein (a) is a front view including a cross section of the main part; ) Is a cross-sectional view taken along line AA in (a), and (c) is a cross-sectional view taken along line BB in (a).

FIG. 10 shows the operation of the valve gear for the internal combustion engine according to the third embodiment of the present invention in the high lift mode. It is a figure for explaining an operation, where (a) is a plan view, (b) is a cross-sectional view taken along line A—A in (a), and (c) is a line B—B in (b). (D) is a sectional view taken along the line CC in (b).

FIG. 11 is an exploded perspective view of a valve gear for an internal combustion engine showing a fourth embodiment of the present invention.

FIG. 12 is a view for explaining the operation in the low lift mode of the valve operating apparatus for the internal combustion engine according to the fourth embodiment of the present invention, where (a) is a plan view and (b) is ( (a) A cross-sectional view along line A-A, (c) is a cross-sectional view along line B-B in (b), (d) is a cross-sectional view along line CC in (b), (e) It is sectional drawing which follows the DD line of (b).

FIG. 13 is a view for explaining the operation in the high lift mode of the valve gear of the internal combustion engine according to the fourth embodiment of the present invention, where (a) is a plan view, and (b) is ( (a) A cross-sectional view along line A-A, (c) is a cross-sectional view along line B-B in (b), (d) is a cross-sectional view along line CC in (b), (e) It is sectional drawing which follows the DD line of (b).

Explanation of symbols

10 Valve drive system for internal combustion engine

12 Camshaft

14 cams

16 Intake valve

18 Valve stem

20, 20A, 20B, 20C Rocker arm

30 high lift cam

32, 34 Low lift cam

36 Rocker shaft

38, 38A, 38B, 38C Rocker arm body

40 slits

42, 44 Arc-shaped part

46, 48

50 piston

52 Plunger Compression coil spring plug

Cylinder chamber

, 68 Oil passage Auxiliary cylinder chamber Pipette

86, 94, 96 Oinore passage

Claims

The scope of the claims

[1] The camshaft between a cam fixed to a camshaft that is rotationally driven in synchronization with the rotation of the internal combustion engine and a valve stem for applying a biasing force in the valve closing direction to the intake valve or the exhaust valve In the valve operating apparatus of the internal combustion engine in which a rocker arm that transmits a driving force from the valve stem to the valve stem is interposed, the cam is configured by integrating a high lift cam and a low lift cam having different diameters, and the rocker arm A rocker arm main body that is swingably disposed with a part of a rotation region of the high lift cam and the low lift cam as a swing region, and a portion belonging to the rotation region of the high lift cam is included in the portion of the lock arm main body. A slit for idle swinging through which the high lift cam can pass is formed, and a part of the slit belongs to the rotation region of the high lift cam in the rocker arm body. A cylinder chamber including a first space facing and a second space adjacent to the first space and from which the rotational region force of the high lift cam is also removed is formed. The cylinder chamber receives hydraulic pressure or elastic force and receives the hydraulic pressure or elastic force. A piston disposed in the first space or the second space is reciprocally stored, and a hydraulic circuit that stakes the piston against the elastic force and presses it against the first space is connected to the cylinder chamber. When the piston receives the hydraulic pressure of the hydraulic circuit force and is disposed in the first space, the rocker arm applies a driving force to the valve system by contact between the piston and the high lift cam. And when the piston receives the elastic force and is disposed in the second space, the rocker arm is brought into contact with the rocker arm main body and the low lift cam. A valve gear of an internal combustion engine comprising swung in the direction for applying a driving force to Busutemu.

[2] The camshaft between a cam fixed to a camshaft that is driven to rotate in synchronization with the rotation of the internal combustion engine and a valve stem for applying a biasing force in the valve closing direction to the intake valve or the exhaust valve In the valve operating apparatus of the internal combustion engine in which a rocker arm that transmits a driving force from the valve stem to the valve stem is interposed, the cam is configured by integrating a high lift cam and a low lift cam having different diameters, and the rocker arm A rocker arm main body that is swingably disposed with a part of a rotation region of the high lift cam and the low lift cam as a swing region, and a portion belonging to the rotation region of the high lift cam is included in the portion of the lock arm main body. A slit for idle swinging through which a high lift cam can pass is formed, and the rocker arm main body includes the high lift cam. A cylinder chamber is formed which includes a first space, part of which belongs to the rotation region of the ft cam and faces the slit, and a second space adjacent to the first space and from which the force of the rotation region of the high lift cam is also removed. A piston disposed in the first space or the second space is reciprocally stored in the cylinder chamber in accordance with hydraulic pressure, and the piston is pressed into the first space in the cylinder chamber. A first hydraulic circuit and a second hydraulic circuit that presses the piston into the second space are connected, and the piston is disposed in the first space by the hydraulic pressure of the first hydraulic circuit force. When the piston and the high lift cam come into contact with each other, the rocker arm swings in a direction to apply a driving force to the valve stem, and the piston is moved by the second hydraulic circuit force. Placed in space When the can, the contact between the rocker arm body and said low lift cam, a valve gear of an internal combustion engine in which the rocker arm is swung in the direction for applying a driving force to the bar Rubusutemu.

[3] The valve operating apparatus for an internal combustion engine according to claim 1 or 2, wherein the rocker arm is swingably coupled to a rocking shaft, and a force applied from the high lift cam or the low lift cam is a power point. When the point of applying a driving force to the valve stem is an action point, and the connection point with the rocker shaft is a fulcrum, the fulcrum is located between the force point and the action point. A valve operating apparatus for an internal combustion engine characterized by the above.

[4] The valve operating apparatus for an internal combustion engine according to any one of claims 1, 2, and 3, wherein the cylinder chamber is formed in a cylindrical shape, and the piston is formed of a cylindrical body. A valve operating apparatus for an internal combustion engine characterized by the above.