JPH0634150U - Cylinder head with valve seat cut - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose of the 4-cycle gasoline engine manufacturing process is to reduce the engine manufacturing cost by eliminating the work of embedding a separately manufactured valve seat in the cylinder head. [Structure] It is common knowledge to embed a separately manufactured valve seat in the cylinder head, but this requires a lot of man-hours and pushes up the engine manufacturing price. On the other hand, the aluminum alloy was used for the cylinder head, and the valve seat was machined on itself, and as a result of the test operation, wear of the valve seat was not recognized. If the material is more wear resistant than aluminum alloy, the amount of wear should be even smaller. Therefore, if the cylinder head in which the valve seat is processed is used without embedding a separately manufactured valve seat in the cylinder head for the engine as a whole, the engine price can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cylinder head that omits the valve seat normally mounted on the cylinder head of a 4-cycle gasoline engine.

[0002]

[Background of device]

 An intake hole and an exhaust hole are provided in the cylinder head of a 4-cycle Catolin engine, and a valve is attached to each of them. These valves are constantly pressed from the cylinder side to the respective hole openings of the cylinder head by springs attached to the valve stem, and the tips of the respective valve stems resist the spring force during intake and exhaust. The valve is opened by pushing it toward the cylinder side. There are several mechanisms that push the tip of the valve stem, but there is always a fixed gap between the tip of the valve stem and its mechanism. On the other hand, the valve is pushed into the cylinder at the time of intake and exhaust, but when intake or exhaust ends, it is pulled up by the spring and pressed against the opening of the intake hole or exhaust hole. It is believed that the valve and valve seat will wear out as this operation is repeated thousands of times per minute in high temperatures.

Conventionally, it has been common knowledge for engine designers to make a valve from heat-resistant and wear-resistant metal and to make a valve sheet separately from heat-resistant and wear-resistant metal and to embed it in a cylinder head. It was However, although the number of valve seats for intake and exhaust has recently increased to four recently, it is not easy to embed them in a narrow area in the cylinder head, and it is economically burdensome to manufacture. Is a big job. The applicant of the present application has come to the idea that the contact between the valve and the valve seat is only a small lift lifted by a spring, so it is not a shock but a soft touch, and the valve seat is manufactured separately and embedded. After stopping, a valve seat was processed on the cylinder head itself and a test operation was performed.

The engine is a high-speed rotation 25 cc for model airplane, and the structural accuracy is the same as that of a normal engine. The wear test is indistinguishable from a practical engine. The tester is of type gasoline 4 cycle output 2.5PS displacement 25cc cylinder number 1 cruise rotation 9000rpm rotation range 2,000-10,000rpm cylinder head material AC8A (wear resistant aluminum alloy) test time is 50 hours. As a result of the test, when the gap between the valve stem tip and the valve operating mechanism was measured, the gap to be decreased was increased from 0.05 mm to 0.15 mm. If the valve seat wears, the tip of the valve stem should rise and the gap should decrease. This means that the amount of wear on the contact surface between the valve stem tip and the valve mechanism is greater than the amount of wear on the valve seat. In other words, it can be considered that the valve seat cut into the cylinder head itself has a smaller wear amount than that of the valve train of a practical machine, and is thus considered to be practical.

[0005]

[Problems to be solved by the device]

 This invention eliminates the expensive manufacturing work of embedding a valve seat of another material in the cylinder head, and reduces the engine manufacturing process to reduce the engine price and the weight of the aluminum alloy engine. With the goal.

[0006]

[Means for solving problems]

 The present invention is a cylinder head in which a valve seat made of a different material is not embedded in the cylinder head, and the valve seat is cut on the cylinder head itself.

[0007]

[Effect] Even if the material for the cylinder head is AC8A and the valve sheet is machined as in the above test, it has been found that the valve seat wear is small and does not impair practical use. No need for complicated processing to embed a valve seat made of a different material. Since the amount of wear is small as a result of using an aluminum alloy in this way, the above facts are compatible with the materials used in the general engine.

[0008]

【Example】

 FIG. 1 is an explanatory view of a valve operating mechanism using a rocker arm of the present invention. FIG. 2 is an explanatory view of a conventional cylinder head. Reference numeral 1 is a cylinder, and 2 is a cylinder head. The cylinder head 2 is provided with an intake hole 3 and an exhaust hole 3 and opens into the cylinder 1. The opening is machined in the halve seat 4 and the valve 5 is attached. The balf 5 is always pulled upward by the spring 6, but a fine gap 10 exists between the valve stem tip 7 and the contact end 9 of the rocker arm 8 except when in contact. If, for example, the valve seat 4 is worn during the test operation, the gap 10 should be small, but the test result is large. The larger amount indicates that the wear amount of the valve sheet 4 is smaller than the wear amount of the valve stem tip portion 7 and the contact end portion 9 of the rocker arm 8, and the latter is in a practical range. The wear amount of the small valve sheet 4 is naturally within the practical range. 2 shows a conventional valve seat 4a embedding structure.

[0009]

[Effect of device]

 Embedding a valve seat made of a different material in the cylinder head is an extremely tedious task, pushing up the engine price. According to the present invention, it is not always necessary to embed a valve seat made of a different material, and the valve seat is cut on the cylinder head itself to reduce the weight of the aluminum alloy engine and reduce the engine price. Can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of a valve operating mechanism using a rocker arm of the present invention.

FIG. 2 is an explanatory diagram of a conventional cylinder head.

[Explanation of symbols]

 1 Cylinder 2 Cylinder Head 3 Intake and Exhaust Holes 4 Valve Seat 4a Conventional Embedded Valve Seat 5 Valve 6 Spring 7 Valve Stem Tip 8 Rocker Arm 9 Rocker Arm Contact End 10 Gap

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area F02F 1/42 G 8503-3G

Claims (1)

[Scope of utility model registration request] 1. A cylinder head in a 4-cycle gasoline engine, in which the valve seat made of another material is stopped and the valve seat is machined on the cylinder head itself.