JP2006291716A - Intake and exhaust valve for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost and weight of an intake and an exhaust valve for an internal combustion engine. <P>SOLUTION: In the intake valve 28 which consists of a stem part 44 and an umbrella part 51 provided on an end part of the stem part 44 and which can adhere a non-circular valve seal surface 52 provided on the umbrella part 51 on a non-circular intake side valve seal provided at an opening part of an intake port 26 opened on a ceiling and having the stem part 44 movably inserted in, a center of gravity 71 of the umbrella part 51 is made roughly coincident with an axial line 44b of the stem part 44. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement of an intake / exhaust valve of an internal combustion engine.

2. Description of the Related Art As an intake / exhaust valve for a conventional internal combustion engine, an umbrella having an elliptical shape is known (for example, see Patent Document 1).
Special table 2003-509616

FIG. 1 of Patent Document 1 will be described with reference to FIG. FIG. 10 is a simplified illustration of the main part of FIG. The code was re-assigned.
FIG. 10 is a cross-sectional view of a cylinder head showing a conventional intake / exhaust valve. A duct 102 is opened in the cylinder head 101, a guide 103 is provided in the middle of the duct 102, and a shaft (shaft portion) of the valve 104 is provided in the guide 103. 106 is movably inserted, and an elliptical head (umbrella portion) 107 of the valve 104 is disposed in the opening of the duct 102 on the combustion chamber side, and the rocker 108 is driven. A structure for opening and closing is described.

  Since the head 107 of the valve 104 is elliptical, the center of gravity of the head 107 is located away from the axis of the shaft 106. When the valve 104 reciprocates along the guide 103, a bending moment is generated at the base portion of the head 107 due to the inertial force acting on the center of gravity of the head 107. The greater the position of the center of gravity of the head 107 is far from the axis of the shaft 106, or the higher the engine speed and the higher the speed of reciprocating motion, the greater the bending moment that is generated. The diameter must be increased or the cross-section must be reinforced to reinforce the head 107 itself or the connecting portion between the shaft 106 and the head 107, resulting in an increase in weight and cost.

  An object of the present invention is to reduce the weight and cost of an intake / exhaust valve of an internal combustion engine.

  The invention according to claim 1 includes a shaft portion and an umbrella portion provided at an end portion of the shaft portion, and a guide hole opened in the ceiling for opening and closing a port provided in the ceiling of the combustion chamber of the internal combustion engine. In the intake / exhaust valve in which the shaft portion is movably inserted and the non-circular valve seal surface provided in the umbrella portion can be in close contact with the non-circular valve seat provided in the opening portion of the port. The center of gravity position is substantially matched with the axis of the shaft portion.

  The center of gravity of the umbrella part of the intake / exhaust valve is substantially matched to the axis of the shaft part, so that the distance from the axis of the shaft part to the center of gravity of the umbrella part is reduced, and the umbrella acts by the inertial force acting on the center of gravity of the umbrella part. Reduce the bending moment generated at the root of the part. If the bending moment is reduced, it is possible to make the shaft portion thinner and the umbrella portion thinner.

The invention according to claim 2 is characterized in that the thickness of the umbrella portion is made non-uniform.
If the thickness of the portion of the umbrella that protrudes greatly from the axis of the shaft is reduced and the thickness of the portion of the umbrella that protrudes slightly from the axis of the shaft is increased, the center of gravity of the umbrella approaches the axis of the shaft. .

  The invention according to claim 3 is characterized in that the position of the axis of the shaft portion is moved relative to the umbrella portion. By moving the axis of the shaft part to substantially the center of the umbrella part, the axis of the shaft part approaches the center of gravity of the umbrella part.

  In the invention according to claim 1, since the center of gravity position of the umbrella portion is substantially matched with the axis of the shaft portion, the bending generated in the intake and exhaust valves due to the inertial force acting on the center of gravity of the umbrella portion of the non-circular intake and exhaust valve. The moment can be reduced, and the shaft portion of the intake / exhaust valve can be made thinner, and the intake / exhaust valve can be reduced in weight and size by reducing the thickness of the umbrella portion. Moreover, it is not necessary to make the umbrella part or the connecting part between the shaft part and the umbrella part into a complicated shape that can withstand a large bending moment, and the cost can be reduced.

  In the invention according to claim 2, since the thickness of the umbrella portion is made non-uniform, for example, the thickness of the portion that greatly protrudes from the axis of the shaft portion in the umbrella portion is reduced, and the thickness of the umbrella portion is decreased from the axis of the shaft portion. By increasing the wall thickness of the protruding part, the center of gravity of the umbrella can be almost matched with the axis of the shaft, and the center of gravity of the umbrella can be more reliably aligned with the axis of the shaft. become.

  In the invention according to claim 3, since the position of the axis of the shaft portion is moved with respect to the umbrella portion, the center of gravity of the umbrella portion is quickly moved to the axis of the shaft portion by moving the axis of the shaft portion to the center of the umbrella portion. Can be adapted to Therefore, even when the shape of the intake / exhaust valve is changed, it is an effective means for quickly responding.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a cross-sectional view of an internal combustion engine employing an intake / exhaust valve according to the present invention (first embodiment). The internal combustion engine 10 is movable to a cylinder block 11 and a cylinder bore 12 provided in the cylinder block 11. An inserted piston 13, a connecting rod 16 connected to the piston 13 via a piston pin 14, and a crankshaft 18 that is rotatably attached to the lower portion of the cylinder block 11 and supports the connecting rod 16 with a crankpin 17 so as to be swingable. Prepare.

  The cylinder block 11 includes a cylinder part 21 provided at the upper part and a skirt part 23 provided integrally at the lower part of the cylinder part 21, and a member having a cylinder head 24 attached to the upper part via a head gasket (not shown). It is.

  The cylinder head 24 includes an intake port 26 and an exhaust port 27 communicating with the combustion chamber 25. The intake port 26 is opened and closed by an intake valve 28, and the exhaust port 27 is opened and closed by an exhaust valve 29.

  Here, 31 is a sliding bearing interposed between the large end portion 16a of the connecting rod 16 and the crank pin 17, 32 is a counterweight provided on the crankshaft 18, and 33 is a crankcase formed by the skirt portion 23. An underskirt portion 36 is attached to the lower portion of the skirt portion 23 with a plurality of bolts 34, 36 is an oil pan attached to the lower portion of the underskirt portion 33 with a plurality of bolts 38 via an undercase 37, and 41 is an intake valve 28 closed. When the exhaust valve 29 is closed, the intake valve seat 42 forms a seal surface with the intake valve 28. When the exhaust valve 29 is closed, the exhaust valve seat 42 forms a seal surface with the exhaust valve 29, and 43 is an ignition plug. is there.

  FIG. 2 is a perspective view showing an intake / exhaust valve (first embodiment) according to the present invention, and an intake valve 28 (here, the reference numerals of the two intake valves are identified as 28A and 28B) on the ceiling of the combustion chamber 25. .) And that the exhaust valve 29 is arranged.

The intake valve 28 includes a shaft portion 44 having a circular cross section and a umbrella portion 51 provided integrally at the tip of the shaft portion 44, and presses the end portion 44a of the shaft portion 44 from the cam (not shown) side. As a result, the umbrella portion 51 is moved to the piston 13 (see FIG. 1) side of the combustion chamber 25 to open the intake port 26 (see FIG. 1), and the elastic force of the contracted valve spring (not shown) is used as the shaft portion. By acting on 44, the umbrella part 51 is moved to the ceiling side of the combustion chamber 25, and the intake port 26 is closed.
The shaft portion 44 includes a protrusion (not shown) in the vicinity of the end portion 44a, and the protrusion is guided in the axial direction by a groove provided on the cylinder head 24 (see FIG. 1) side, whereby the shaft of the intake valve 28 is provided. Prevent rotation around.
The umbrella portion 51 is a portion in which an annular valve seal surface 52 is formed on one side surface 51a (the surface on which the shaft portion 44 extends) in order to form a seal surface.

  The exhaust valve 29 includes a shaft 47 having a circular cross section and an umbrella 54 integrally provided at the tip of the shaft 47, and presses the end 47a of the shaft 47 from the cam (not shown) side. As a result, the umbrella portion 54 is moved to the piston 13 side of the combustion chamber 25 to open the exhaust port 27 (see FIG. 1), and the elastic force of the contracted valve spring (not shown) acts on the shaft portion 47. By doing so, the umbrella part 54 is moved to the ceiling side of the combustion chamber 25 and the exhaust port 27 is closed.

The shaft portion 47 includes a protrusion (not shown) in the vicinity of the end portion 47a, and the protrusion is guided in the axial direction by a groove provided on the cylinder head 24 side to prevent rotation of the exhaust valve 29 around the shaft. .
The umbrella portion 54 is a portion in which an annular valve seal surface 55 is formed on one side surface 54a (the surface on which the shaft portion 47 extends) in order to form a seal surface.

  FIG. 3 is a plan view showing an intake / exhaust valve (first embodiment) according to the present invention. The intake valves 28A and 28B are orthogonal to a straight line 57 drawn parallel to the direction in which the crankshaft 18 (see FIG. 1) extends. In addition, the members are arranged symmetrically with respect to a straight line 58 passing through the center of the cylinder bore 12, each of the umbrella portions 51 is made into a substantially leaf-like shape, that is, a non-circular shape, and the shaft portion 44 is arranged in parallel to the straight line 58 in plan view. Is. A hatched portion of the umbrella portion 51 is a valve seal surface 52. Here, the axis of the shaft portion 44 is 44b.

  The exhaust valve 29 is a member in which the umbrella portion 54 is formed in a non-circular shape symmetrical with respect to the straight line 58, and the shaft portion 47 is made to coincide with the straight line 58 in plan view. A hatched portion of the umbrella portion 54 is a valve seal surface 55.

  FIG. 4 is a bottom view (first embodiment) showing the ceiling of the combustion chamber of the cylinder head according to the present invention. The ceiling 61 of the combustion chamber 25 (see FIG. 1) provided in the cylinder head 24 is symmetrical to a straight line 58. The two intake side valve seats 41 (here, the two intake side valve seats are referred to as 41A and 41B) are mounted close to the intake side valve seats 41A and 41B and symmetrical to the straight line 58 on the ceiling 61. It shows that the exhaust-side valve seat 42 having a simple shape is attached. The hatched portions of the intake side valve seats 41A and 41B are the valve seat seal surfaces 62, and the hatched portions of the exhaust side valve seats 42 are the valve seat seal surfaces 63.

  An inner wall surface 65 as an inner surface of the ceiling 61 is a concave surface 66 having a concave curved surface including the contours 62a and 63a of the valve seat seal surfaces 62 and 63, and a substantially flat and annular shape provided around the concave surface 66. And a squish surface 67.

The concave surface 66 is a portion in which a plug mounting hole 68 for attaching a spark plug (not shown) is formed in the approximate center.
The squish surface 67 is a portion that forms a squish portion with the crown portion of the piston 13 (see FIG. 1), and forms a squish portion with a narrow gap at the end of the compression stroke of the piston 13, and the air-fuel mixture in this squish portion is removed. Extrusion causes the air-fuel mixture in the combustion chamber to flow and increases the combustion speed.

5 (a) and 5 (b) are explanatory views for explaining the intake / exhaust valve (first embodiment) according to the present invention. Since the intake valve 28 and the exhaust valve 29 shown in FIG. 2 have the same basic shape, only the intake valve 28 will be described below.
2A is a view taken in the direction of the arrow 5 in FIG. 2, and the axis 44 b of the shaft portion 44 of the intake valve 28 is indicated by a white circle, and the center of gravity 71 of the umbrella portion 51 of the intake valve 28 is indicated by a black circle. That is, it shows that the center of gravity 71 of the umbrella portion is substantially matched with the axis 44b of the shaft portion 44. The distance between the axis 44b of the shaft portion 44 and the center of gravity 71 of the umbrella portion 51 is L1, and when the outer diameter of the shaft portion 44 is D, the distance L1 is smaller than half of the outer diameter D (that is, L1 <0. 5D).

  (B) is a sectional view taken along the line bb of (a), and the umbrella portion 51 is a portion whose thickness is varied depending on the place, that is, a non-uniform portion. For example, the thickness of the shaft portion 44 far from the axis 44b is t1, and the thickness of the portion close to the axis 44b of the shaft portion 44 is t2 (t2> t1) larger than the thickness t1, so that the umbrella portion The center of gravity 71 of 51 is brought close to the axis 44b of the shaft portion 44 so as to substantially match.

FIGS. 6A and 6B are explanatory views showing another example (second embodiment) of the intake and exhaust valves according to the present invention.
(A) is the figure seen along the axial line 83 of the axial part 82 of the intake valve 81, the axial line 83 is shown by a white circle, and the gravity center 86 of the umbrella part 84 of the intake valve 81 is shown by a black circle.
That is, the position of the axis 83 of the shaft portion 82 is moved to the approximate center of the umbrella portion 84, and the center of gravity 86 of the umbrella portion 84 is brought close to the axis 83 of the shaft portion 82 so as to substantially match. The distance between the axis 83 of the shaft portion 82 and the center of gravity 86 of the umbrella portion 84 is L2, and when the outer diameter of the shaft portion 82 is D, the distance L2 is smaller than half of the outer diameter D and is almost zero (that is, 0). .5D> L2≈0).

(B) is a sectional view taken along the line bb of (a). The umbrella portion 84 is substantially symmetric with respect to the axis line 83 of the shaft portion 82, and the center of gravity 86 of the umbrella portion 84 substantially matches the axis line 83 of the shaft portion 82. To do.
Since the axis line 83 of the shaft portion 82 is simply moved almost to the center of the figure of the umbrella portion 84, the position of the center of gravity of the umbrella portion 84 can be set very easily and quickly.

7A and 7B are explanatory views showing a comparative example of intake and exhaust valves.
(A) shows the axis 123 of the shaft part 122 of the intake valve 121 as a white circle, and the center of gravity 126 of the umbrella part 124 of the intake valve 121 as a black circle. The distance between the axis 123 of the shaft portion 122 and the center of gravity 126 of the umbrella portion 124 is L3. If the outer diameter of the shaft portion 122 is D, the distance L3 is larger than half of the outer diameter D (that is, L3> 0. 5D and L3> L1 (see FIG. 5A)).

  (B) is a bb line sectional view of (a), and umbrella part 124 is the part which made the thickness t3 the same in each place. Therefore, the center of gravity 126 exists on the side of the shaft portion 122 of the umbrella portion 124 that protrudes greatly from the axis 123, and the center of gravity 126 is far away from the axis 123.

8A and 8B are operation diagrams showing the operation of the intake and exhaust valves.
In the comparative example shown in FIG. 7A (as shown in FIG. 7), when the intake valve 121 is guided by the valve guide 128 and reciprocates, the inertia force F3 is applied to the center of gravity 126 in the direction of the figure, for example. Works. Since the distance between the axis 123 of the shaft portion 122 and the center of gravity 126 is L3, M3 = F3 · L3 acts as a bending moment M3 on the root portion of the umbrella portion 124 in the shaft portion 122.

  In the embodiment shown in FIG. 5B (shown in FIG. 5), when the intake valve 28 is guided by the guide hole 24a of the cylinder head and reciprocates in the axial direction of the shaft portion 44, the umbrella portion 51 Inertial force F1 acts on the center of gravity 71, for example, in the direction shown in the figure. Since the distance between the axis 44b of the shaft portion 44 and the center of gravity 71 of the umbrella portion 51 is L1, M1 = F1 · L1 acts as a bending moment M1 on the root portion of the umbrella portion 51 in the shaft portion 44.

  In the above (a) and (b), L1 <L3, and the thickness of the portion of the umbrella portion 51 of the embodiment that largely protrudes from the axis 44b of the shaft portion 44 with respect to the umbrella portion 124 of the comparative example. Since the weight of the umbrella portion 51 is smaller than the weight of the umbrella portion 124, F1 <F3, and therefore M1 <M3.

  In the intake valve 121 of the comparative example, for example, the shaft portion 122 is thickened, the umbrella portion 124 is thickened, or the connecting portion between the shaft portion 122 and the umbrella portion 124 is provided so as to withstand a large bending moment M3. It is necessary to change the shape for reinforcement.

  In the intake valve 28 of the embodiment, the shaft portion 44 can be made a thin shaft with respect to the intake valve 121 of the comparative example, and the wall of the umbrella portion 51 itself or the joint portion between the shaft portion 44 and the umbrella portion 51 can be used. The thickness can be further reduced, and the intake valve 28 can be further reduced in weight.

  FIG. 9 is a cross-sectional view showing an intake / exhaust valve (third embodiment) according to the present invention. The intake valve 91 substantially matches the center of gravity 96 of the umbrella portion 94 with the axis 93 of the shaft portion 92, and further the shaft portion. By providing the hollow part 97 in 92, further weight reduction is achieved.

  In this way, the weight of the umbrella portion 94 is reduced by making the center of gravity 96 of the umbrella portion 94 substantially coincide with the axis 93 of the shaft portion 92, and the weight of the shaft portion 92 is reduced by forming the hollow portion 97 in the shaft portion 92. Thus, the load on the rocker shaft and valve spring for driving the intake valve 91 can be reduced, the weight of the rocker shaft and valve spring can be reduced, and the internal combustion engine can be rotated at a higher speed. it can.

  As shown in FIGS. 1, 4, and 5, the present invention first includes the shaft portion 44 and the umbrella portion 51 provided at the end portion of the shaft portion 44, and includes a combustion chamber of the internal combustion engine 10. 25, in order to open and close the intake port 26 as a port provided on the ceiling 61, the shaft portion 44 is movably inserted into a guide hole 24a (see FIG. 8B) opened in the ceiling 61, and the intake port 26 In the intake valve 28 in which the non-circular valve seal surface 52 provided in the umbrella 51 can be brought into close contact with the non-circular intake-side valve seat 41 provided in the opening of the The shaft portion 44 is substantially matched with the axis 44b.

  Since the position of the center of gravity 71 of the umbrella part 51 substantially coincides with the axis 44b of the shaft part 44, the bending moment generated in the intake valve 28 due to the inertial force acting on the center of gravity 71 of the umbrella part 51 of the non-circular intake valve 28 M1 (see FIG. 8B) can be reduced, and the intake valve 28 can be reduced in weight and size by reducing the shaft 44 of the intake valve 28 and reducing the thickness of the umbrella 51. Further, it is not necessary to make the umbrella portion 51 or the connecting portion between the shaft portion 44 and the umbrella portion 51 into a complicated shape that can withstand a large bending moment, and the cost can be reduced.

Secondly, the present invention is characterized in that the thickness of the umbrella portion 51 is not uniform.
Since the thickness of the umbrella portion 51 is not uniform, for example, the thickness t1 of the portion of the umbrella portion 51 that greatly protrudes from the axis 44b of the shaft portion 44 is reduced, and the thickness t1 of the umbrella portion 51 is decreased from the axis 44b of the shaft portion 44. By increasing the thickness t2 of the protruding portion, the position of the center of gravity 71 of the umbrella part 51 can be substantially matched with the axis 44b of the shaft part 44, and the position of the center of gravity 71 of the umbrella part 51 is It becomes possible to match the axis 44b more reliably.

Third, the present invention is characterized in that the position of the axis 83 of the shaft portion 82 of the intake valve 81 is moved with respect to the umbrella portion 84 as shown in FIG.
Since the position of the axis 83 of the shaft portion 82 is moved with respect to the umbrella portion 84, the position of the center of gravity 86 of the umbrella portion 84 can be changed to the axis of the shaft portion 82 by moving the axis 83 of the shaft portion 82 to the center of the umbrella portion 84. 83 can be adjusted almost quickly. Therefore, even when the shape of the intake valve 81 is changed, it is an effective means for quickly responding.

  In addition, in this embodiment, as shown in FIG.5 (b), although the thickness of the umbrella part 51 was changed gradually, not only this but a recessed part was provided partially, or a convex part By providing the thickness, the thickness may be changed to be non-uniform.

  The intake / exhaust valve of the present invention is suitable for an internal combustion engine.

It is sectional drawing of the internal combustion engine which employ | adopted the intake / exhaust valve | bulb (1st Embodiment) which concerns on this invention. 1 is a perspective view showing an intake / exhaust valve (first embodiment) according to the present invention. It is a top view which shows the intake / exhaust valve | bulb (1st Embodiment) which concerns on this invention. It is a bottom view (1st Embodiment) which shows the ceiling of the combustion chamber of the cylinder head which concerns on this invention. It is explanatory drawing explaining the intake / exhaust valve | bulb (1st Embodiment) which concerns on this invention. It is explanatory drawing which shows another Example (2nd Embodiment) of the intake / exhaust valve | bulb which concerns on this invention. It is explanatory drawing which shows the comparative example of an intake / exhaust valve | bulb. It is an action figure which shows the effect | action of an intake / exhaust valve. It is sectional drawing which shows the intake / exhaust valve | bulb (3rd Embodiment) which concerns on this invention. It is sectional drawing of the cylinder head which shows the conventional intake / exhaust valve | bulb.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 24a ... Guide hole, 25 ... Combustion chamber, 26, 27 ... Port (intake port, exhaust port), 28, 29, 81, 91 ... Intake / exhaust valve, 41, 42 ... Valve seat (intake side valve) Seat, exhaust side valve seat), 44, 47, 82, 92 ... shaft portion, 44b, 47b, 83, 93 ... shaft axis, 51, 54, 84, 94 ... umbrella portion, 52, 55 ... valve seal surface 61, ceiling, 71, 86, 96, the center of gravity of the umbrella, t1, t2, the wall thickness of the umbrella.

Claims (3)

A shaft portion and an umbrella portion provided at the end of the shaft portion, and the shaft portion can be freely moved in a guide hole opened in the ceiling to open and close a port provided in the ceiling of the combustion chamber of the internal combustion engine. In the intake / exhaust valve that can be inserted into the non-circular valve seat provided in the opening of the port, and the non-circular valve seal surface provided in the umbrella portion can be closely attached,
An intake / exhaust valve for an internal combustion engine, wherein the position of the center of gravity of the umbrella portion is substantially matched with the axis of the shaft portion.   2. An intake / exhaust valve for an internal combustion engine according to claim 1, wherein the thickness of the umbrella portion is made non-uniform.   The intake / exhaust valve for an internal combustion engine according to claim 1, wherein the position of the axis of the shaft portion is moved with respect to the umbrella portion.

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