JPH0639077Y2 - Engine cylinder head structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a cylinder head structure of an engine, and more particularly to a structure having a communication groove for communicating oil between the bearing surfaces of valve springs.

(Prior Art) Conventionally, as a cylinder head structure of an engine, for example, as disclosed in Japanese Utility Model Publication No. 60-27799, two valve openings are provided in the cylinder row direction for each cylinder, and the valve openings are provided in the valve openings. While inserting the stems of the intake and exhaust valves, a fuel injection nozzle mounting boss is provided between the two valve openings, the upper end of the fuel injection nozzle mounting boss is connected to the top deck, and the lower end is connected to the bottom deck. It is known that a fuel injection nozzle is fitted into the fuel injection nozzle attachment boss and is attached to the top deck of the cylinder head with bolts.

(Problems to be solved by the invention) By the way, in such an engine, seating surfaces that are recessed in an annular shape are formed around the valve openings of the top deck, and the valve springs are arranged on the seating surfaces. I have to. In that case, a communication groove that communicates the seat surfaces with each other is formed between the adjacent seat surfaces in the cylinder row direction, and the oil accumulated on one seat surface is guided to the other seat surface through the communication groove. It is performed from this seat surface to the lower part of the top deck. Since the top deck below the communication groove also functions as a rib, the rigidity of the cylinder head against bending moment in the direction orthogonal to the cylinder row is improved.

However, in such an engine, the central portion of the top deck tends to float up due to the tightening force of the fuel injection nozzle mounting bolt, and the tightening of the cylinder head bolt arranged at the end of the cylinder head in the direction orthogonal to the cylinder row. Since both ends try to sink due to the force, a large bending moment acts in the cylinder row direction of the cylinder head. For this reason, stress concentrates on the communication grooves formed in the cylinder row direction, which may cause cracks and the like.

The present invention has been made in view of such a point, and an object thereof is to make the communication groove for communicating the above-mentioned seating surfaces into an arc shape and appropriately set the radius and the depth thereof, and It is to improve the rigidity of the cylinder head while ensuring the oil introduction function.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the communication groove is formed on an arc to improve the rigidity against a bending moment in the direction orthogonal to the cylinder row, while the radius of the arc is changed in the cylinder row direction. Is set so as to avoid stress concentration on the bending moment, and the depth of the communication groove is set so that the oil is surely guided from one seat surface to the other seat surface.

Specifically, the solution means taken by the present invention is to provide a plurality of valve openings through which the valve stems are inserted in the cylinder row direction,
It is premised on a cylinder head structure of an engine provided with a fuel injection nozzle mounting boss connected to the bottom deck and the top deck and having a fuel injection nozzle mounted between the valve openings. On the other hand, a seat surface is formed around each valve opening portion in the top deck, which is recessed in an annular shape and on which the valve spring is arranged. Further, a communication groove that communicates the seating surfaces is formed between adjacent seating surfaces in the cylinder row direction. Further, the communication groove is formed in an arc shape whose cross section has a center above the top deck.
In that case, the arc radius of the communication groove is set to be larger than the height from the upper surface of the top deck to the lower end of the wall forming the communication groove, and the depth of the communication groove from the top deck top surface to the seat surface is set. The depth is set to be half or more than half.

(Operation) According to the present invention, in the present invention, the oil on one of the adjacent seating surfaces is guided to the other seating surface through the communication groove and flows from this seating surface to the lower portion of the top deck.

Further, since the communication groove is formed in the cylinder row direction, the rigidity of the cylinder head with respect to the bending moment in the cylinder row orthogonal direction is improved.

Further, since the arc radius of the communication groove is set to be larger than the height from the upper surface of the top deck to the lower end of the wall forming the communication groove, even if the cylinder head receives a bending moment in the cylinder row direction, the cylinder head is connected to the communication groove. It is possible to avoid stress concentration.

Moreover, since the depth of the communication groove from the top deck upper surface is set to be half or more than the depth from the top deck upper surface to the seat surface, the oil introduction function between the seat surfaces is ensured.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an in-line 4-cylinder diesel engine having a cylinder head structure according to an embodiment of the present invention. In these figures, 1 is a cylinder block, 2 is a cylinder head arranged on the cylinder block 1, and
Cylinders 4, 4, ... Are formed between the cylinder block 1 and the cylinder head 2, and pistons 5 are slidably fitted in the respective cylinders 4. The cylinder head 2 is fastened to the cylinder block 1 by a plurality of cylinder head bolts 3, 3 ... Further, the bottom surface of the cylinder head 2 is formed on the bottom deck 8 and the upper surface is formed on the top deck 9, and a water jacket 10 for circulating cooling water between the bottom deck 8 and the top deck 9. Are formed.

Further, the cylinder head 2 is provided with an intake port 11 and an exhaust port 12 for each cylinder 4. Each of the ports 11 and 12 has one end open to each cylinder 4 and the other end to the side surface of the cylinder head 2. Each port 11,12
Are formed so that the cylinder 4 side openings are aligned in the cylinder row direction. An intake valve 13 and an exhaust valve 14 for opening and closing the ports 11 and 12 are provided in the intake port 11 and the exhaust port 12, respectively. Further, as shown in FIG. 3, an intake valve opening portion that connects the intake ports 11 and the top deck 9 to the cylinder head 2 and inserts the stem of the intake valve 13 therethrough.
18 and an exhaust valve opening 19 for connecting the exhaust ports 12 and the top deck 9 and inserting the stem of the exhaust valve 14 therethrough. The valve openings 18, 19
Are formed so as to form a line in the cylinder row direction, like the openings of the ports 11 and 12 on the cylinder 4 side.

Further, as shown in FIG. 1, a fuel injection nozzle 21 is attached between the intake valve opening 18 and the exhaust valve opening 19 of the cylinder head 2. That is, the cylinder head 2 is formed with a fuel injection nozzle mounting boss 22 that connects the bottom deck 8 and the top deck 9 to each other. The fuel injection nozzle 21 is fitted into the mounting boss 22 and the top deck 9 is bolted. Installed by 23.

Further, annular seating surfaces 26 and 27 are formed around the intake valve openings 18 and around the exhaust valve openings 19 of the top deck 9. Each seat 26,
Valve springs 25 are arranged at 27, respectively, and urge the intake valve 13 and the exhaust valve 14 in the valve closing direction. An oil drain groove 28 extending in the direction orthogonal to the cylinder row and communicating with the lower portion of the top deck 9 is formed in the top deck 9 on the side of each intake seat surface 26, and the oil discharge groove 28 is collected on each intake seat surface 26. The oil is made to flow to the lower part of the top deck.

Further, the intake seat surface 26 and the exhaust seat surface of each of the cylinders 4 described above.
A communication groove 31 that communicates the seating surfaces 26, 27 with each other is formed in the cylinder row direction. As shown in FIG.
The cross section of the communication groove 31 is formed in an arc shape having a center above the top deck 9. The arc radius ρ of the communication groove 31 is set larger than the height D from the upper surface 9a of the top deck 9 to the lower end 9b of the wall forming the communication groove 31. The depth h of the communication groove 31 from the top deck upper surface 9a is set to be half or more than half the depth H from the top deck upper surface 9a to the seat surfaces 26, 27. Specifically, for example, ρ = 25 mm, D = 14 mm, h = 4 mm.

Therefore, in the above-described embodiment, the oil accumulated in the exhaust seat surface 27 for each cylinder 4 is guided to the intake seat surface 26 via the communication groove 31, and the oil discharge groove 28 is introduced from the seat surface 26.
It flows to the lower part of the top deck 9 through the and is collected.

Further, since the communication groove 31 is formed in the cylinder row direction, the rigidity of the cylinder head 2 against a bending moment in the cylinder row orthogonal direction is improved.

Further, since the arc radius ρ of the communication groove 31 is set to be larger than the height D from the upper surface of the top deck 9 to the lower end 9b of the wall forming the communication groove 31, the cylinder head 2 is bent in the cylinder row direction. Even if a moment is applied, stress concentration on the communication groove 31 can be avoided. Specifically, if the height d from the bottom surface of the communication groove 31 to the lower end 9b of the wall forming the communication groove 31 is d = 10 mm, then ρ / d = 2.5, D / d = 1.4 The concentration coefficient σ _K is approximately 1.0, which shows that stress concentration can be avoided. In this case, in order to reduce the stress as much as possible, it is preferable that ρ / D be 1.0 or more. Therefore, the arc radius ρ should be larger than the height D.

Moreover, since the depth h of the communication groove 31 from the top deck upper surface 9a is set to be half or more than the depth H from the top deck upper surface 9a to the seat surfaces 26, 27, the seat surface 2
The oil introduction function between 6 and 27 is secured. The reason for this is that the communication groove 31 is a cast surface, because the communication groove 31 is a casting surface.
This is because a step difference of up to about half the depth H can be formed between 26 and 27.

As described above, according to the engine cylinder head structure of the present invention, a plurality of valve openings through which the valve stems are inserted are provided in the cylinder row direction, and the bottom deck and the top are provided between the valve openings. In a cylinder head structure of an engine provided with a fuel injection nozzle mounting boss that is connected to a deck and to which a fuel injection nozzle is mounted, a seat in which a valve spring is arranged in an annular recess around each valve opening in the top deck. Communication grooves are formed in the cylinder row direction between the adjacent seating surfaces to communicate the seating surfaces with each other, and the cross section of the communication groove is formed in an arc shape centered above the top deck. And the radius of the circular arc of the communication groove is set larger than the height from the upper surface of the top deck to the lower end of the wall forming the communication groove, and the top of the communication groove is formed. The depth from the top of the deck is set to half or more than the depth from the top of the top deck to the seating surface, so that the rigidity of the cylinder head against bending moment in the direction perpendicular to the cylinder row is ensured while maintaining the oil introduction function between the seating surfaces. Therefore, it is possible to prevent the stress from being concentrated on the communication groove due to the bending moment in the cylinder row direction.

[Brief description of drawings]

The drawings illustrate an embodiment of the present invention. FIG. 1 is a vertical sectional side view of an essential part of an engine, FIG. 2 is a plan view of a cylinder head, and FIG.
FIG. 4 is a vertical side view of the same, and FIG. 4 is a vertical side view of the communication groove. 2 ... Cylinder head, 4 ... Cylinder, 8 ... Bottom deck, 9 ... Top deck, 13 ... Intake valve, 14 ...
… Exhaust valve, 18 …… Valve opening, 19 …… Valve opening, 21 …… Fuel injection nozzle, 22 …… Fuel injection nozzle mounting boss, 23 …… Bolt, 25 …… Valve spring, 26 ……
Seat surface, 27 …… Seat surface, 31 …… Communication groove.

Claims (1)

[Scope of utility model registration request] 1. A fuel injection nozzle mounting boss which is provided with a plurality of valve openings through which a valve stem is inserted and which is connected to a bottom deck and a top deck and has a fuel injection nozzle mounted between the valve openings. In the provided engine cylinder head structure, seating surfaces are formed around the valve openings in the top deck, in which annular recesses are formed, and the valve springs are arranged, and the seating surfaces are formed between adjacent seating surfaces. A communication groove for communicating the seating surfaces is formed in the cylinder row direction, and the communication groove is formed in an arc shape whose cross section has a center above the top deck. The arc radius of the communication groove is the top deck. The height from the upper surface of the upper deck to the lower end of the wall forming the communication groove is set larger than the height of the communication groove, and the depth of the communication groove from the upper surface of the top deck is from the upper surface of the top deck. A cylinder head structure for an engine, characterized in that it is set to more than half to half the depth to.