JP2006152837A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To position a camshaft 3 relative to a cylinder head 1 in a thrust direction in an internal combustion engine of such a structure that a cam carrier 2 in which the camshaft 3 is stored is separated from a cylinder head 1. <P>SOLUTION: The camshaft 3 comprises a cam part 10, a camshaft journal part 11 having an outer diameter larger than that of the rotating locus Q of the cam part 10, and a camshaft positioning flange part 12 formed at positions other than those of the cam part 10 and the camshaft journal part 11. A positioning projection 16 engaged with the camshaft positioning flange part 12 is projectedly formed on the upper part of the cylinder head 1. Thus, even if the cam carrier 2 is so structured that it is separated from the cylinder head 1, the camshaft 3 can be accurately positioned relative to the cylinder head 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine in which a cam carrier that supports a camshaft is attached to an upper portion of a cylinder head.

Patent Document 1 discloses an internal combustion engine in which a cam bearing portion that rotatably supports a cam journal portion of a valve camshaft is integrated with a cylinder head. In Patent Document 1, the cam journal portion is formed to be larger than the maximum outer diameter of the cam provided on the valve operating camshaft.
Japanese Patent Laid-Open No. 9-53427

  However, such a configuration of Patent Document 1 has a problem that it is difficult to position the valve camshaft in the thrust direction with respect to the cylinder head.

  Therefore, according to the present invention, a cam carrier that rotatably supports the camshaft is attached to the upper part of the cylinder head, and the camshaft has a larger outer diameter than the cam portion and the rotation locus of the cam portion. In the internal combustion engine having the camshaft journal portion, the camshaft is formed with a camshaft positioning flange portion at a position other than the cam portion and the camshaft journal portion, and the upper portion of the cylinder head with respect to the camshaft positioning flange portion. The positioning protrusions to be engaged with each other are formed to protrude.

  According to the present invention, the position of the camshaft is determined by the cylinder head, and the camshaft is positioned even if the cam carrier supporting the camshaft is an internal combustion engine having a structure divided from the cylinder head. It can be carried out with high accuracy.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  1 and 2 show a schematic configuration of a main part of the internal combustion engine in the present embodiment.

  The present embodiment is an example applied to an in-line four-cylinder internal combustion engine. As shown in FIGS. 1 and 2, the cylinder head 1 includes an intake valve side cam carrier 2 a separate from the cylinder head 1, and An exhaust valve side cam carrier 2b is attached. These cam carriers 2a and 2b are arranged in parallel with each other across a center line along the direction of the engine cylinder of the internal combustion engine, and are fixed to the cylinder head 1 by bolts (not shown).

  An intake camshaft 3a for driving the intake valve is rotatably accommodated and supported on the intake valve side cam carrier 2a. An exhaust camshaft 3b that drives the exhaust valve is rotatably accommodated and supported by the exhaust valve side cam carrier 2b.

  As shown in FIG. 2, the camshaft 3 (the intake camshaft 3a and the exhaust camshaft 3b) protrudes from one end side in the longitudinal direction of the cam carrier 2 (the intake valve side cam carrier 2a and the exhaust valve side cam carrier 2b). A cam sprocket 4 is fixed to one end (the left end in FIG. 2) with a bolt 5. A timing chain 6 is wound around each cam sprocket 4a, 4b, and rotation from a crankshaft (not shown) is transmitted.

  In FIG. 1, 7 is a cylinder block and 8 is a spark plug. 1 and 2 is a chain case attached to one end of the internal combustion engine so as to cover the cam sprocket 4 and the timing chain 6.

  As shown in FIGS. 2 and 3, the intake camshaft 3 a and the exhaust camshaft 3 b have cam portions 10 that determine the valve opening characteristics of the intake and exhaust valves, and the outer diameters of the cam tracks 10 than the rotation trajectory Q of each cam portion 10. Is formed at a position other than the cam portion 10 and the camshaft journal portion 11, and has a smaller diameter than the camshaft journal portion 11. And are provided. In the present embodiment, the camshaft positioning flange portion 12 is further outside (on the left side in FIGS. 2 and 3) the camshaft journal portion 11 a located on the most end side (the left side in FIGS. 2 and 3) of the camshaft 3. Is provided.

  As shown in FIGS. 1 to 3, the cam carrier 2 is an elongated, substantially rectangular parallelepiped casing, in which a plurality of bearing portions 13 that rotatably support the camshaft journal portion 11 are formed.

  Further, as shown in FIGS. 2 and 3, the cam carrier 2 has a positioning projection hole 14 and a projection hole 15 at positions symmetrical to the center position P in the longitudinal direction of the cam carrier. And are formed. That is, the intake valve side cam carrier 2a and the exhaust valve side cam carrier 2b are formed so that the shape along the longitudinal direction thereof is substantially symmetrical with respect to the center position P in the longitudinal direction of each cam carrier 2. Yes. Therefore, the intake valve side cam carrier 2a and the exhaust valve side cam carrier 2b are symmetrical with respect to the engine center line along the engine cylinder row direction, and the intake valve side cam carrier 2a is viewed from above the engine. When rotated by 180 °, the exhaust valve side cam carrier 2b has substantially the same shape, in particular, the outer shape is the same.

  The positioning projection hole 14 and the projection hole 15 are formed on the surface (bottom surface) attached to the cylinder head upper portion of the cam carrier 2, and the cam carrier 2 is attached to the cylinder head 1 upper portion. At this time, the positioning projection hole 14 is engaged with the positioning projection 16 formed to protrude from the upper portion of the cylinder head 1, and the projection portion hole 15 is engaged with the projection 17. In the present embodiment, the positioning projection hole 14 is formed at one end in the longitudinal direction of each cam carrier 2a, 2b (the left end in FIGS. 2 and 3), and the projection hole 15 is formed in each cam carrier. 2a and 2b are formed at the other end in the longitudinal direction (the right end in FIGS. 2 and 3).

  The cam carrier 2 is positioned with respect to the cylinder head 1 by engaging with the positioning protrusion 16 and the protruding portion 17, and the cam shaft 3 is positioned with respect to the cylinder head 1 by engaging with the positioning protrusion 16. In other words, the positioning protrusion 16 is formed on the cylinder head 1 so that the cam carrier 2 and the camshaft 3 are positioned at a predetermined position of the cylinder head 1, and the protrusion 17 is positioned at a predetermined position of the cylinder head 1. It is formed on the upper part of the cylinder head 1 so as to be positioned.

  The positioning protrusion 16 is formed integrally with the cylinder head 1 and, as shown in FIGS. 1 to 3, is engaged with the positioning protrusion hole 14 of the cam carrier 2 in the engine width direction (FIG. 2, FIG. 2). 3 and a cam shaft journal projecting from the upper end surface of the base end portion 18 and facing the cam shaft positioning flange portion 12 adjacent to the cam shaft positioning flange portion 12. The front end portion 19 is generally composed of an elongated end portion 19 in the engine width direction (the direction perpendicular to the paper surface in FIGS. 2 and 3) sandwiched between the portions 11a. That is, the positioning protrusion 16 is formed to engage with the camshaft positioning flange portion 12. The distal end portion 19 of the positioning projection 16 is formed so as to be thinner in the engine cylinder row direction and shorter in the engine width direction than the base end portion 18 of the positioning projection 16.

  Specifically, the positioning protrusion 16 is formed so that the proximal end portion 18 and the distal end portion 19 are linearly continuous on the back surface on the adjacent camshaft journal portion side, and on the front surface on the positioning flange portion side, The part 18 and the tip part 19 are formed so as to be continuous in a substantially stepped shape. Further, both side surfaces of the positioning projection 16 are substantially stepped at a portion where the base end portion 18 and the tip end portion 19 are continuous.

  When the cam carrier 2 is attached to the cylinder head 1, the back surface of the positioning protrusion 16 comes into contact with the positioning protrusion hole 15 and the camshaft journal 11 a on one end side. A part of the front end of the positioning protrusion 16 on the front end side, that is, a part of the front end portion 19 abuts on the camshaft positioning flange portion 12. Of the both side surfaces of the positioning protrusion 16, the portion corresponding to the base end portion 18 abuts against the inner wall surface of the cam carrier 2.

  Further, the camshaft 3 in the section between the camshaft positioning flange portion 12 and the camshaft journal portion 11a on one end side facing and adjacent to the camshaft positioning flange portion 12 is provided at the distal end portion 19 of the positioning projection 16. A receiving semicircular cutout 20 is formed.

  Further, the positioning protrusion 16 is formed with a guide portion that performs a guide function when the cam carrier 2 and the cam shaft 3 are attached to the cylinder head 1. More specifically, in this embodiment, the back end side of the front end portion 19, the front end side of the base end portion 18, and the front end sides of both side surfaces of the base end portion 18 are obliquely cut out to form guide portions. Each surface 21 is formed. The inclined surface 21b on the front surface front end side of the base end portion 18 is in the height direction of the positioning protrusion 16 (vertical direction in FIGS. 2 and 3) with respect to the inclined surfaces 21c and 21c on the front end sides of both side surfaces of the base end portion 18. Is set to be small. Here, the inclined surfaces 21a and 21b on the rear surface front end side of the front end portion 19 and the front surface front end side of the base end portion 18 are arranged in the engine cylinder row direction of the cam carrier 2 and the cam shaft 3 (cam carrier longitudinal direction or cam shaft axial direction). ), And the inclined surfaces 21c and 21c on the distal end sides of both side surfaces of the base end portion 18 guide the insertion of the cam carrier 2 in the engine width direction (the direction perpendicular to the camshaft axis). It is.

  The protrusion 17 is a substantially rectangular protrusion that is elongated in the engine width direction, and is integrally formed with the cylinder head 1. The protrusion 17 engages with the protrusion hole 15 of the cam carrier 2 when the cam carrier 2 and the cam shaft 3 are attached to the cylinder head 1.

  Also in the protrusion 17, a guide portion that performs a guide function when the cam carrier 2 and the camshaft 3 are attached to the cylinder head 1 is formed. More specifically, in the present embodiment, the front surface of the protrusion 17 facing the camshaft journal portion 11e located on the most other end side in the cam carrier longitudinal direction (the right side in FIGS. 2 and 3), the front surface of the protrusion 17 The inclined surface 22 is formed on the tip side of the back surface of the projection portion 17 that is substantially parallel to the front surface and the front surface of the projection portion 17 and both side surfaces orthogonal to the back surface (on the tip side of the both side surfaces of the projection portion 17). The formed inclined surface is not shown).

  4 to 6 are explanatory views schematically showing an outline of a process of attaching the cam carrier 2 and the camshaft 3 to the cylinder head 1.

  As shown in FIG. 4, the camshaft 3 is inserted into the cam carrier 2 from the other end side. When the camshaft 3 is inserted into the cam carrier 2, the camshaft 3 is allowed to move in the cam carrier longitudinal direction (the thrust direction of the camshaft 3), that is, positioning is not performed along the cam carrier longitudinal direction. It is in a state. As shown in FIGS. 5 and 6, the cam carrier 2 is attached to the upper part of the cylinder head 1 with the camshaft 3 inserted. At this time, the cam carrier 2 is positioned relative to the cylinder head 2 by the positioning protrusion 16 and the protrusion 17, and the camshaft 3 is positioned relative to the cylinder head 1 by the positioning protrusion 16.

More specifically, the camshaft 3 is positioned in the thrust direction, that is, positioned relative to the cylinder head 1 by engaging the camshaft positioning flange portion 12 and the positioning projection 16.
7 to 12 are explanatory views schematically showing the function of the positioning protrusion 16 when the cam carrier 2 with the camshaft 3 inserted is attached to the cylinder head 1 in time series.

  The cam carrier 2 into which the camshaft 3 is inserted is attached to the cylinder head 1 from above the cylinder head 1 (FIG. 7). When the distal end portion 19 of the positioning projection 16 is inserted into the positioning projection hole portion 14, the inclined projection 21a formed on the distal end side rear surface of the distal end portion 19 causes the positioning projection 16 to enter the positioning projection hole portion 14. Insertion is guided (FIG. 8). The distal end portion 19 of the positioning projection 16 enters between the camshaft positioning flange portion 12 and the camshaft journal portion 11a on the one end side facing and adjacent to the camshaft positioning flange portion 12, thereby The camshaft 3 is positioned (FIG. 9). Then, when the base end portion 18 of the positioning projection 16 enters the positioning projection hole 14, the cam carrier 2 is first positioned in the engine cylinder row direction with respect to the cylinder head 1 (FIG. 10), and then the cylinder head 1 The cam carrier 2 is positioned with respect to the engine width direction (FIG. 11). When the bottom surface of the cam carrier 2 comes into contact with the upper portion of the cylinder head 1, the camshaft positioning flange portion 12 and the camshaft positioning flange portion 12 are adjacent to the notch portion 20 formed at the distal end portion 19 of the positioning protrusion 16. Then, the camshaft 3 in the section between the camshaft journal portion 11a on the opposite end side is received (FIG. 12), and in this state, the cam carrier 2 is fixed to the cylinder head 1 by bolts (not shown). Is done.

  As described above, in this embodiment, the position of the camshaft 3 is determined by the cylinder head 1, and the cam carrier 2 that supports the camshaft 3 is divided from the cylinder head 1. Even in an internal combustion engine, the camshaft 3 can be accurately positioned with respect to the cylinder head 1.

  The positioning projections 16 can simultaneously position the camshaft 3 and the cam carrier 2 with respect to the cylinder head 1.

  Further, the cam carrier 2 is positioned on the cylinder head 1 at both ends in the engine cylinder row direction by the positioning protrusions 16 and the protrusions 17, whereby the cam carrier 2 can be accurately positioned with respect to the cylinder head 1.

  Since the positioning protrusion 16 and the protrusion 17 are respectively formed with inclined surfaces 21 and 22 for guiding insertion of the cam carrier 2 into the positioning protrusion hole 14 or the protrusion hole 15, the cam carrier 2 and the camshaft 3 can be easily positioned with respect to the cylinder head 1.

  Further, in the present embodiment, the intake valve side cam carrier 2a and the exhaust valve side cam carrier 2b are symmetrical with respect to the engine center line along the engine cylinder row direction, and the intake valve side cam carrier 2a. When viewed from above the engine, it is rotated by 180 ° to have approximately the same shape as the exhaust valve side cam carrier 2b, and in particular the outer shape is the same. Therefore, it is possible to share the substantially box-shaped base material processed into the intake valve side cam carrier 2a and the substantially box-shaped base material processed into the exhaust valve side cam shaft 2b, thereby reducing the cost. Can be achieved.

  In the embodiment described above, the positioning projection 16 is sandwiched between the camshaft positioning flange portion 12 and the camshaft journal portion 11a on one end side. However, as shown in FIG. A concave groove 31 is formed at the tip of 16, and the concave groove 31 and the outer periphery of the camshaft positioning flange portion 12 are fitted to the cylinder head side peripheral edge so that the camshaft 3 is positioned relative to the cylinder head 1. Also good.

  The technical idea of the present invention that can be grasped from the above embodiment will be listed together with the effects thereof.

  (1) An internal combustion engine in which the cam carrier that rotatably supports the camshaft is attached to the upper part of the cylinder head, and the camshaft has a larger outer diameter than the cam portion and the rotation locus of the cam portion. In an internal combustion engine having a camshaft journal portion having a diameter and supported by the camshaft journal portion with respect to the cam carrier, the camshaft is positioned at a position other than the cam portion and the camshaft journal portion. A flange portion is formed, and a positioning projection that engages with the camshaft positioning flange portion is formed to protrude from the upper portion of the cylinder head. As a result, the position of the camshaft is determined by the cylinder head, and the camshaft is accurately positioned even if the cam carrier that supports the camshaft is an internal combustion engine that is divided from the cylinder head. can do.

  (2) In the internal combustion engine according to (1), when the cam carrier is attached to the upper part of the cylinder head, the positioning protrusion protrudes from the positioning protrusion hole provided in the cam carrier into the inside of the cam carrier. It is comprised so that it may engage with a use hole part and a camshaft positioning flange part. As a result, the camshaft and the cam carrier can be simultaneously positioned with respect to the cylinder head.

  (3) In the internal combustion engine according to (2), a protrusion that engages with the cam carrier is formed to protrude from the upper portion of the cylinder head, and a protrusion hole corresponding to the protrusion is formed on the cam carrier. A positioning projection hole is formed on one end side in the longitudinal direction of the cam carrier, and a projection hole is formed on the other end side in the longitudinal direction of the cam carrier. Thus, the cam carrier is positioned with respect to the cylinder head at both ends in the engine cylinder row direction.

  (4) In the internal combustion engine according to (3), the cam carrier has an elongated, substantially rectangular parallelepiped shape, and the positioning protrusion and the protrusion are formed when the cam carrier is attached to the upper part of the cylinder head. It is formed at a position that is symmetric with respect to the center in the longitudinal direction. The cam carriers attached to the upper part of the cylinder head are an intake valve side cam carrier that supports an intake camshaft for an intake valve and an exhaust valve side cam carrier that supports an exhaust camshaft for an exhaust valve. The internal combustion engine body is arranged in parallel with the center line along the engine cylinder row direction. Further, the positioning projection hole and the projection hole formed in the cam carrier are symmetrical with respect to the center in the longitudinal direction of the cam carrier.

  That is, the intake valve side cam carrier and the exhaust valve side cam carrier are symmetrical with respect to the engine center line along the engine cylinder row direction, and the exhaust valve side cam carrier is exhausted when rotated 180 ° when viewed from above the engine. It has substantially the same shape as the valve-side cam carrier.

  Therefore, it is possible to share the substantially box-shaped base material processed into the intake valve side cam carrier and the substantially box-shaped base material processed into the exhaust valve side cam shaft, thereby reducing the cost. It becomes possible.

  (5) In the internal combustion engine according to (3) or (4), the positioning protrusion and the protrusion are each formed with a positioning protrusion hole or a guide portion that guides insertion into the protrusion hole. Yes. Accordingly, the cam carrier can be easily attached to the cylinder head in a short time, and the cycle time of the assembly process can be shortened.

Explanatory drawing which shows the principal part schematic structure of the internal combustion engine which concerns on this invention. Explanatory drawing which shows the principal part schematic structure of the internal combustion engine which concerns on this invention. The disassembled perspective view of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. The assembly drawing of the principal part of the internal combustion engine which concerns on this invention. Explanatory drawing which shows other embodiment of the internal combustion engine which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Cam carrier 3 ... Cam shaft 10 ... Cam part 11 ... Cam shaft journal part 12 ... Cam shaft positioning flange part 13 ... Bearing part 14 ... Positioning projection hole 15 ... Projection part hole 16 ... Positioning projection 17 ... Projection Part

Claims (5)

An internal combustion engine in which a cam carrier that rotatably supports a camshaft is attached to an upper portion of a cylinder head,
In an internal combustion engine in which a camshaft has a cam portion and a camshaft journal portion whose outer diameter is larger than the rotation trajectory of the cam portion, and is supported by the camshaft journal portion with respect to the cam carrier. The camshaft has a camshaft positioning flange portion formed at a position other than the cam portion and the camshaft journal portion, and a positioning projection that engages with the camshaft positioning flange portion is formed at the upper portion of the cylinder head. An internal combustion engine characterized by comprising:   When the cam carrier is attached to the upper part of the cylinder head, the positioning projection protrudes from the positioning projection hole provided on the cam carrier into the cam carrier and engages the positioning projection hole and the camshaft positioning flange. The internal combustion engine according to claim 1, wherein the internal combustion engine is configured as described above.   A protrusion that engages with the cam carrier is formed on the upper portion of the cylinder head, and a protrusion hole corresponding to the protrusion is formed on the cam carrier. The positioning protrusion hole is on one end side in the longitudinal direction of the cam carrier. The internal combustion engine according to claim 2, wherein the projection hole is formed on the other end side in the longitudinal direction of the cam carrier.   The cam carrier has an elongated, substantially rectangular parallelepiped shape, and the positioning protrusion and the protrusion are formed at positions that are symmetrical with respect to the longitudinal center of the cam carrier when the cam carrier is attached to the upper part of the cylinder head. The internal combustion engine according to claim 3, wherein   5. The internal combustion engine according to claim 3, wherein the positioning protrusion and the protrusion are each formed with a positioning protrusion hole or a guide portion that guides insertion into the protrusion hole.

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