JP5811065B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

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

  2. Description of the Related Art A variable valve operating apparatus for an internal combustion engine includes two small cams and large cams connected to a camshaft and having different sizes, and first and second rocker arms driven by the small cams and the large cams, respectively. is there. The first and second rocker arms are connected and separated from each other by the action of hydraulic pressure. The first and second rocker arms are supported by the rocker arm shaft in a swingable manner. Patent Documents 1 and 2 disclose such a variable valve operating apparatus for an internal combustion engine.

JP 2008-75479 A JP 2006-299875 A

  The rocker shaft extends parallel to the camshaft and is rotatably held by the cylinder head. For this reason, the variable valve operating apparatus is increased in size.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a variable valve operating device for an internal combustion engine that is miniaturized.

  The object is directly held by a first cam that rotates together with a camshaft, a second cam that rotates together with the camshaft and is larger than the first cam, and a cam cap disposed on an upper portion of a cylinder head, or the cam cap A support shaft held by a support member fixed to the support shaft, a first swing arm that is swingably supported by the support shaft and swings by the first cam and drives a rocker arm, and swings by the support shaft. A second swinging arm supported and swingable by the second cam and retracted from the rocker arm, and a first swinging the first and second swinging arms toward the first and second cams. A variable valve operating apparatus for an internal combustion engine, comprising: 1 and a second urging member; a connecting member for connecting or releasing the second swing arm to the first swing arm by the action of hydraulic pressure; Thus it can be achieved.

  A variable valve operating apparatus for an internal combustion engine that is downsized can be provided.

FIG. 1 is an external view of the variable valve operating apparatus of the present embodiment. FIG. 2 is a view of the variable valve operating apparatus as viewed from above. FIG. 3 is a view of the variable valve apparatus as viewed from the axial direction of the camshaft S. FIG. 4 is a view of the variable valve operating apparatus that has passed through the swing arm. FIG. 5 is an explanatory diagram of connection and release of the swing arm. FIG. 6 is an explanatory diagram of connection and release of the swing arm. FIG. 7 is a sectional view of the camshaft. FIG. 8 is an explanatory diagram of a method of fixing the support member. FIG. 9 is an explanatory diagram of a variable valve operating apparatus according to a first modification. FIG. 10 is an explanatory view of a variable valve operating apparatus according to a first modification. FIG. 11 is an explanatory diagram of a variable valve operating apparatus according to a second modification. FIG. 12 is an explanatory diagram of a variable valve operating apparatus according to a second modification.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

  FIG. 1 is an external view of a variable valve apparatus 1 of the present embodiment. FIG. 2 is a view of the variable valve operating apparatus 1 as viewed from above. The variable valve operating apparatus 1 is employed in an internal combustion engine mounted on a vehicle or the like. The variable valve gear 1 lifts the valve V through the rocker arm RR described later by the rotation of the camshaft S. One end of the rocker arm RR is supported by a hydraulic lash adjuster RA. The other end of the rocker arm RR presses the proximal end of the valve V. The valve V is an intake valve or an exhaust valve. The lash adjuster RA may be an external oil supply type lash adjuster using engine oil or a sealed lash adjuster in which hydraulic oil is sealed. The lash adjuster RA is swingably supported with one end of the rocker arm RR as a fulcrum. The lash adjuster RA is disposed at the upper part of the cylinder head.

  The variable valve operating apparatus 1 includes a camshaft S to which cams C1 and C2 are fixed, a support member 10, and swing arms 20 and 30. The swing arms 20 and 30 are examples of first and second swing arms, respectively. The cams C1 and C2 are fixed to the camshaft S with a predetermined interval. Further, the tips of the cams C1 and C2 are fixed to the camshaft S in the same direction and rotate together with the camshaft S. The cam C2 is larger than the cam C1. Specifically, the cams C1 and C2 have the same short diameter (the diameter of the base circle), but the long diameter is larger in the cam C2. Cams C1 and C2 are examples of first and second cams, respectively.

  The support member 10 includes a cylindrical portion 11, two arm portions 13, and two arm portions 15. The camshaft S passes through the cylindrical portion 11. The arm portion 13 protrudes upward from the tube portion 11 and is fixed to a cam cap described later. The arm portion 15 protrudes radially outward from the tube portion 11, and the support shaft RS passes therethrough to hold the support shaft RS. The support member 10 is located between the cams C1 and C2. The arm portion 13 is fixed to the cam cap so that the cam shaft S slides and rotates within the cylindrical portion 11 of the support member 10. Details will be described later.

  The swing arm 20 includes a body portion 21 and two arm portions 25. The body portion 21 has a substantially rectangular shape extending in parallel with the camshaft S. The arm portion 25 protrudes upward from the trunk portion 21, and the support shaft RS passes therethrough. As will be described in detail later, the body portion 21 is provided with a swing lever that drives the two rocker arms RR. The swing arm 30 is provided adjacent to the swing arm 20. The swing arm 30 includes a trunk portion 31 and an arm portion 35. The body portion 31 is adjacent to the body portion 21 of the swing arm 20. The arm part 35 protrudes upward from the trunk | drum 31, and the support shaft RS has penetrated. That is, the swing arms 20 and 30 have a support shaft RS that penetrates in common, and are supported to be swingable around the support shaft RS.

  The body 21 of the swing arm 20 and the body 31 of the swing arm 30 are pushed by cams C1 and C2, respectively. As the cams C1 and C2 rotate, the swing arms 20 and 30 swing within a predetermined range around the support shaft RS, respectively. Two springs SP <b> 2 and SP <b> 3 are wound around the cylindrical portion 11 of the support member 10. The spring SP2 is wound around the cylindrical portion 11 on the cam C1 side. The spring SP3 is wound around the cylindrical portion 11 on the cam C2 side. The springs SP2 and SP3 return the swing arms 20 and 30 swinged by the cams C1 and C2, respectively, to their original positions. Specifically, one end of the spring SP2 and one end of the spring SP3 are urged so that the trunk portions 21 and 31 are in contact with the cams C1 and C2, respectively. The springs SP2 and SP3 are examples of first and second urging members, respectively. The cams C1 and C2 swing the swing arms 20 and 30 against the urging force of the springs SP2 and SP3. Since the cam C2 is larger than the cam C1 as described above, the swing range of the swing arm 30 is larger than the swing range of the swing arm 20.

  FIG. 3 is a view of the variable valve apparatus 1 as seen from the axial direction of the camshaft S. The body portion 21 of the swing arm 20 is provided with a lever portion 28 that protrudes toward the rocker arm RR. The lever portion 28 pushes the two rocker arms RR as the swing arm 20 swings. As a result, the two rocker arms RR are driven and the two valves V are lifted. Here, the swing arm 30 is not provided with such a swing lever, and is provided at a retracted position where it does not contact the two rocker arms RR.

  FIG. 4 is a diagram of the variable valve operating apparatus 1 that has passed through the swing arms 20 and 30. In the swing arms 20 and 30, a connecting pin P is provided for connecting or releasing the both by the action of hydraulic pressure. The connection pin P is an example of a connection member. The connecting pin P is provided so as to be commonly inserted into the trunk portion 21 of the swing arm 20 and the trunk portion 31 of the swing arm 30. Here, when the connecting pin P does not connect the swing arms 20 and 30, the swing arms 20 and 30 swing in different swing ranges by the cams C1 and C2, respectively. As described above, unlike the swing arm 20, the swing arm 30 is not provided with a swing lever and is retracted from the two rocker arms RR, so that the rocker arm RR cannot be driven. The arm 20 drives the two rocker arms RR. When the swing arms 20 and 30 are connected by the connecting pin P, the swing arm 20 swings in the same swing range as the swing arm 30 along with the swing arm 30 having a large swing range. For this reason, when the swing arms 20 and 30 are connected, the swing arm 20 can drive the two rocker arms RR more greatly, and the lift amount of the valve V increases.

  Next, connection of the swing arms 20 and 30 by the connection pin P and release of the connection will be described. 5 and 6 are explanatory views of the connection and release of the swing arms 20 and 30. FIG. FIG. 5 shows a case where the swing arms 20 and 30 are interlocked. The variable valve operating apparatus 1 of the present embodiment is supplied with oil from an oil pump via an OCV (oil control valve). The OCV is controlled by control from an ECU (electronic control unit). Hydraulic chambers 21 </ b> R and 31 </ b> R are provided in the body portion 21 of the swing arm 20 and in the body portion 31 of the swing arm 30, respectively. The hydraulic chambers 21R and 31R are formed at positions that are coaxially aligned with each other in a state where the swing arms 20 and 30 are not swinged by the cams C1 and C2. The hydraulic chamber 31R houses a coiled spring SP5 having one end fixed to the bottom surface of the hydraulic chamber 31R and the other end fixed to the connecting pin P. The spring SP5 urges the connecting pin P so that the connecting pin P is detached from the hydraulic chamber 31R and inserted into the hydraulic chamber 21R. The hydraulic chambers 21R and 31R are formed so that oil can be supplied via the OCV.

  Specifically, the variable valve apparatus 1 is formed with a passage T1 communicating from the OCV into the hydraulic chamber 21R, and a passage T2 communicating from the OCV to the hydraulic chamber 31R. The passage T1 passes through the camshaft S, passes through the arm portion 15 of the support member 10 on the cam C1 side, passes through the arm portion 25 and the trunk portion 21 of the swing arm 20 on the cam C1 side, and hydraulically passes. It communicates with the chamber 21R. The passage T2 passes through the camshaft S, passes through the arm portion 15 of the support member 10 on the cam C2 side, passes through the arm portion 35 and the trunk portion 31 of the swing arm 30, and communicates with the hydraulic chamber 31R. ing. FIG. 7 is a cross-sectional view of the camshaft S. The passages H1 and H2 that respectively bear a part of the passages T1 and T2 are formed separately from each other. 5 and 6, the passage T1 seems to pass through the arm portion 25 of the swing arm 20 on the cam C2 side, but in reality, a path is formed without the arm portion 25 on the cam C2 side. It has not been.

  When oil is supplied to the passage T1 and discharged from the passage T2 by the OCV, the connecting pin P receives the pressure of the oil and moves from the hydraulic chamber 21R to the hydraulic chamber 31R in the hydraulic chambers 21R and 31R. Inserted in common into the hydraulic chambers 21R, 31R. Thereby, the swing arms 20 and 30 are connected.

  When oil is supplied to the passage T2 and discharged from the passage T1 by the OCV, the connecting pin P receives the pressure of the oil and moves from the hydraulic chamber 31R to the hydraulic chamber 21R in the hydraulic chambers 21R and 31R. The pin P is detached from the hydraulic chamber 31R. Thereby, the connection of the swing arms 20 and 30 is released.

  Next, a method for fixing the support member 10 will be described. FIG. 8 is an explanatory diagram of a method for fixing the support member 10. The camshaft S is supported by a bearing portion G formed in an upper part of the cylinder head SH and extending in a plate shape in a direction perpendicular to the camshaft S. A cam cap CP is fixed to the bearing portion G from above so as to cover the camshaft S. The support member 10 is fixed to the cam cap CP. Specifically, the arm portion 13 of the support member 10 is fixed to the cam cap CP by the fixing pin FP so that the support member 10 does not rotate. In FIG. 8, only the camshaft S, the support member 10, and the support shaft RS are shown.

  Thus, the variable valve operating apparatus 1 of the present embodiment is not supported by the cylinder head except for the camshaft S. For this reason, for example, the engine provided with the variable valve operating apparatus 1 of the present embodiment can be manufactured by diverting the cylinder head or cylinder block of an engine that is not scheduled to be mounted with the variable valve operating apparatus. In other words, the engine components can be used without changing the position of the camshaft of an engine that is not planned to be equipped with a variable valve gear. Thereby, parts, such as a cylinder head, can be made common by the engine which is not provided with the variable valve apparatus, and the engine which is provided with the variable valve apparatus 1 of a present Example. Thereby, the manufacturing cost of the engine is suppressed.

  Further, as shown in FIG. 3, when viewed from the axial direction of the camshaft S, the support shaft RS is disposed at a position that intersects the locus of the apex of the cam C2. That is, the support shaft RS is disposed close to the camshaft S. For this reason, the variable valve apparatus 1 of the present embodiment is downsized. Further, the support shaft RS of the present embodiment is disposed between the cams C1 and C2. For this reason, the support shaft RS is formed short. For this reason, the variable valve operating apparatus 1 of the present embodiment is further miniaturized.

  Further, in the variable valve operating apparatus 1 of the present embodiment, the support shaft RS is held by the support member 10. For this reason, for example, it is not necessary to provide a bearing portion for supporting the support shaft RS in the cylinder head. For this reason as well, a cylinder head of an engine that does not include a variable valve operating device can be used.

  Moreover, in the variable valve operating apparatus 1 of the present embodiment, the rocker arm RR is supported by the lash adjuster RA. For this reason, the valve clearance can be automatically maintained at zero. The rocker arms of Patent Documents 1 and 2 described above are supported by a rocker shaft so as to be swingable. For this reason, since such a rocker arm swings around a rocker shaft, a lash adjuster RA cannot be provided for such a rocker arm. For this reason, in the variable valve operating apparatus 1 of the present embodiment, the valve clearance is automatically maintained at zero, and the maintainability is improved.

  Next, a variable valve apparatus 1a according to a first modification will be described. 9 and 10 are explanatory diagrams of a variable valve operating apparatus 1a according to a first modification. In the variable valve operating apparatus 1a, cams C1 and C2, a support member 10a, and swing arms 20a and 30 are provided for one rocker arm RR. Accordingly, two sets of cams C1 and C2, a support member 10a, and swing arms 20a and 30 are provided for the two rocker arms RR. Accordingly, the lever portion of the swing arm 20a drives a single rocker arm RR. A support member 10a is disposed between the adjacent cams C1 and C2. The support member 10a is formed in a plate shape. On the support shaft RSa held by the support member 10a, swing arms 20a and 30 are supported in a swingable manner in common. Adjacent swing arms 20a, 30 are disposed between adjacent cams C1, C2. Two sets of springs SP2 and SP3 for urging the swing arms 20a and 30 are also provided. The support shaft RSa is also provided at a position that intersects the locus of the apex of the cam C2. For this reason, size reduction of the variable valve apparatus 1a is achieved.

  Similar to the variable valve operating apparatus 1, the adjacent swing arms 20a and 30 are connected to or disconnected from each other by a pin that is operated by hydraulic pressure. For example, the passage T1 communicates with the hydraulic chamber 21R formed in each of the two swing arms 20a from the passage H1. The passage T2 communicates with the hydraulic chambers 31R formed in the two swing arms 30 from the passage H2.

  Next, a variable valve gear 1b according to a second modification will be described. 11 and 12 are explanatory views of a variable valve operating apparatus 1b according to a second modification. As shown in FIGS. 11 and 12, two cam caps CP are fixed to the upper part of the cylinder head SH on the frame when viewed from above. The swing arms 20b and 30b are supported by the cam cap CP so as to be swingable. Specifically, the cam cap CP holds the support shaft RSb, and the swing arms 20b and 30b are supported to be swingable with respect to the support shaft RSb. Therefore, the variable valve apparatus 1b is not provided with the support members 10 and 10a. For this reason, the variable valve apparatus 1b is reduced in the number of parts, and is reduced in weight and size.

  In the above embodiment, the case where the cam cap CP is directly fixed to the upper part of the cylinder head SH has been described as an example, but the present invention is not limited to this. For example, it may be a cam cap that is fixed to an upper portion of the cylinder head and fixed to a cam housing having a bearing portion for supporting the camshaft. In other words, any cam cap disposed on the top of the cylinder head may be used.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

  In the above embodiment, switching from the state in which oil is supplied to the passage T1 to the state in which oil is supplied to the passage T2 moves the connecting pin P to release the connection of the swing arms 20 and 30. However, the present invention is not limited to such a configuration. For example, the supply of oil to both the passages T1 and T2 is stopped after the oil is supplied to the passage T1, and the connecting pin P is connected to the hydraulic chamber only by the biasing force of the spring SP5. It may be separated from 31R and inserted into the hydraulic chamber 21R. Further, the connecting pin P may be connected to the hydraulic chamber 21R side by the spring SP5.

  Alternatively, the lift amount of the valve V may be set to zero by removing the nose portion of the cam C1. Thus, when the swing arms 20 and 30 are not connected, the valve V can be stopped even when the camshaft S is rotating.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Variable valve apparatus S Camshaft RR Rocker arm V Valve C1, C2 Cam 10 Support member 13, 15, 25, 35 Arm part 20, 30 Swing arm (1st and 2nd rocking arm)
21R, 31R Hydraulic chamber 28 Lever part P Connection pin (connection member)
T1, T2 path SP2, SP3 Spring (first and second urging members)

Claims (4)

A first cam that rotates with the camshaft;
A second cam that rotates with the camshaft and is larger than the first cam;
A support shaft held directly on a cam cap disposed on the top of the cylinder head, or held on a support member fixed to the cam cap;
A first swing arm that is swingably supported by the support shaft and is rocked by the first cam to drive a rocker arm;
A second swing arm supported swingably on the support shaft and swinging by the second cam and retracted from the rocker arm;
First and second biasing members for biasing the first and second swing arms toward the first and second cams, respectively.
A connecting member for connecting or releasing the connection of the second swing arm to the first swing arm by the action of hydraulic pressure;
A variable valve operating apparatus for an internal combustion engine.   The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the support shaft overlaps a locus of an apex of the second cam when viewed from an axial direction of the camshaft.   The variable valve operating apparatus for an internal combustion engine according to claim 1 or 2, wherein the support shaft is disposed between the first and second cams. 4. The variable valve operating apparatus for an internal combustion engine according to claim 1, further comprising a hydraulic lash adjuster that supports the rocker arm.

Images