JP4190210B2 - Engine intake and exhaust valves - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an intake / exhaust valve for an internal combustion engine.
[0002]
[Prior art]
Generally, an intake / exhaust valve is formed integrally with a stem that is slidably inserted into a valve guide of an engine, and a low conical valve plate having a conical valve surface that is seated on the valve seat at the periphery. have. And it is comprised as a normally closed valve urged | biased by the valve spring in the close direction in the edge part vicinity on the opposite side to the valve plate of a stem.
[0003]
On the other hand, the weight reduction of this valve is a major key to improving engine performance. The so-called hollow valve, in which the stem portion is thinned and metal sodium with excellent thermal conductivity is sealed in the space, has a specific gravity. Techniques such as changing to a smaller titanium are well known. In recent years, there has also been proposed one in which a stem and a valve body are integrally formed by press molding (for example, JP-A-2001-317315).
[0004]
[Problems to be solved by the invention]
However, the use of a hollow valve for weight reduction or the use of a light metal material has the disadvantage of increasing the price of the intake and exhaust valves. Thus, there has been a need for a lightweight intake / exhaust valve that can be produced without greatly changing the conventional valve manufacturing method.
[0005]
[Means for Solving the Problems]
The above-described problem is that a circular valve plate having a conical valve face that opens and closes a passage leading to a combustion chamber is integrally provided at one end of a stem that is slidably inserted into a support hole, and a peripheral portion of the valve plate the thickness to form the annular portion is made thicker than the rest of the, reduced diameter end portion which is connected to the valve plate of the stem diameter, portion and an annular original diameter of the stem of reduced diameter portion thereof it Ri is resolved to be reinforced by a plurality of ribs for connecting the parts.
[0006]
In this case, the surface constituting the inner peripheral portion of the annular portion and the surface constituting the portion connecting the original diameter portion and the reduced diameter portion of the stem are inclined with respect to the axis of the stem. And it is preferable to form in the inclined surface mutually parallel .
[0007]
[Action]
Conventionally, the upper surface of the valve plate that has a shallow conical shape (the surface on the intake / exhaust passage side) has been thinned by leaving a rib, and a thick annular ring formed on its periphery Weight reduction is achieved while maintaining rigidity by the portion. A conical valve face is formed on the outer surface of the annular portion, and its shape is accurately maintained by the highly rigid annular portion.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described. In FIG. 1, reference numeral 10 denotes an intake / exhaust valve according to the present invention. The intake / exhaust valve 10 is formed by integrating powder valve metallurgy with a valve plate 12 having an outer diameter of 34 mm having a conical valve surface 11 for seating on a valve seat, and a stem 22 connected to the central portion of the valve plate 12. It is an engine intake valve formed by adding cold forging as required.
[0009]
The valve plate 12 has a plate-like plate-like portion 12a having a plate thickness of about 1 mm and an annular portion 12b which is provided at the periphery of the valve plate 12 and has a large wall thickness. A shaped valve face 11 is formed. As shown in FIG. 2, six ribs 12 c having a thickness of about 2 mm extending from the stem 22 in the radial direction are provided between the valve plate 12 and the stem 22. That is, the rib 12c is formed between the recesses 12d by providing six substantially triangular recesses 12d arranged in the radial direction in a shallow conical portion.
[0010]
The stem 22 has one end connected to the valve plate 12 and the other end in contact with a valve lifter (not shown). 23 is a circumferential groove formed on the outer periphery of the stem 22 and is provided to hold a cotter (not shown) for locking the retainer of the valve spring, as is well known.
[0011]
Note that the shape of the portion connecting the valve plate 12 and the stem 22 is not limited to that described above, and as shown in FIG. 4, the portion contacting the valve plate 12 of the stem 22 can be further reduced in diameter. Weight reduction is possible. In this case, parallel inclined surfaces 13, 13 are provided on the inner peripheral side of the annular portion 12 b and the reduced diameter portion of the stem 22 in order to facilitate die cutting during molding.
[0012]
In the above embodiment, the valve 10 is cut out from the upper surface of the conventional conical valve plate 12 by the recess 12d leaving the rib 12c having a thickness of 2 mm. As a result, the weight of the intake valve, which had been 47.4 g before being lightened, was reduced to 34.8 g.
[0013]
In an actual machine test using a valve spring in which the tension is reduced in accordance with this weight, as shown in FIG. 3, the present invention was applied to an intake valve and an exhaust valve of an engine having fuel consumption characteristics shown in FIG. However, the characteristics shown in FIG. That is, the fuel consumption before the improvement of 38.8 km per liter of gasoline improved to 46.8 km after the improvement.
[0014]
And although only the hollow 12d is thinned and lightened, the required rigidity can be maintained because the valve plate 12 and the stem 22 are connected and reinforced by a plurality of ribs 12c.
[0015]
The effect of reducing the weight becomes more remarkable by reducing the diameter of the end of the stem 22 connected to the valve plate 12 to a small diameter. Furthermore, by forming the annular portion 12b of the valve plate 12 thicker than the remaining portion (the plate-like portion 12a), the rigidity of the valve surface 11 can be maintained high even if the plate-like portion 12a is a thin plate.
[0016]
【The invention's effect】
As described above, according to the first aspect of the present invention, weight reduction can be achieved without increasing the rigidity of the poppet valve and the ventilation resistance of intake and exhaust. Further, by configuring the annular portion to be thicker than the plate-like portion, it is possible to reduce the weight while keeping the rigidity of the valve surface high. Furthermore, the weight can be further reduced by forming the portion connected to the valve plate of the stem to have a smaller diameter than the remaining portion.
[0017]
According to the second aspect of the present invention, by forming the thinned portions into parallel inclined surfaces, it is easy to perform die cutting at the time of molding, and the manufacturing cost can be reduced .
There are effects such as.
[Brief description of the drawings]
[0018]
FIG. 1 is a partially cutaway side view of a poppet valve showing an embodiment of the present invention.
FIG. 2 is a plan view thereof.
FIG. 3 is a characteristic diagram showing the performance of the present poppet valve.
FIG. 4 is a partial side view corresponding to FIG. 1 showing a modification.
[Explanation of symbols]
[0019]
10 .... Poppet valve 11 .... Valve surface 12 .... Valve plate 12a ... Plate-like portion 12b ... Ring portion 12c ... Rib 12d ... Dimple 13 .... Inclined Surface 22 ... Stem 23 ... Circumferential groove (cotter groove)

Claims (2)

A circular valve plate having a conical valve face that opens and closes a passage leading to the combustion chamber is integrally provided at one end of a stem that is slidably inserted into the support hole, and the thickness of the peripheral portion of the valve plate is the remainder. thereby forming an annular portion and thicker, reduced diameter end portion which is connected to the valve plate of the stem diameter, between the portion and the annular portion of the original diameter of the stem of reduced diameter portion thereof Poppet valve reinforced by a plurality of connecting ribs. In Claim 1, the surface which comprises the part of the inner peripheral side in the said annular part, and the surface which comprises the part which ties the part of the original diameter of a stem, and the reduced diameter part with respect to the axis line of a stem A poppet valve formed on inclined surfaces that are inclined and parallel to each other .

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