US-12618356-B2 - Cylinder head structure

US12618356B2US 12618356 B2US12618356 B2US 12618356B2US-12618356-B2

Abstract

A cylinder head structure that can increase the rigidity of an area corresponding to an area between cylinder bores and improve a sealing force of an inter-bore corresponding portion positioned above between adjacent cylinders when enhancing the sealing force between a cylinder block and the cylinder head to improve engine output. The cylinder head structure includes: insertion walls through which right and left fastening bolts arranged between adjacent cylinders pass; a head upper wall connecting upper end portions of a pair of the insertion walls; and a cylinder head bottom wall, and a head cooling water channel is surrounded by those four walls (insertion walls, head upper wall, cylinder head bottom wall), and a vertical wall in a state of extending left and right spanning the head upper wall and the cylinder head bottom wall to block the head cooling water channel is formed between the pair of insertion walls.

Inventors

Tamon Tanaka
Junya IKAI
Kyota Inoue
Atsushi Tanaka
Kazuyuki CHUMA

Assignees

KUBOTA CORPORATION

Dates

Publication Date: 20260505
Application Date: 20230403
Priority Date: 20220630

Claims (4)

1 . A cylinder head structure, wherein, as a front-rear direction is defined by a longitudinal direction of a cylinder head, and a lateral direction is defined by a width direction of the cylinder head intersecting the front-rear direction, the cylinder head assembled on a cylinder block by a plurality of fastening bolts is provided with insertion walls through which the fastening bolts arranged on both sides in the lateral direction between adjacent cylinders in the cylinder block pass, a head upper wall coupling upper end portions of a pair of said insertion walls, a cylinder head bottom wall, a head cooling water channel, and a vertical wall, the head cooling water channel runs along the front-rear direction, one side in the lateral direction is defined as an intake side and another side in the lateral direction is defined as an exhaust side, the head cooling water channel includes an inter-insertion-wall head cooling water channel with the vertical wall being internally mounted and a pair of section head cooling water channels divided into front and rear by the vertical wall, the inter-insertion-wall head cooling water channel is surrounded by the pair of said insertion walls, the head upper wall, and the cylinder head bottom wall is formed, and the vertical wall is formed between the pair of said insertion walls in a state of spanning the head upper wall and the cylinder head bottom wall and extending in the lateral direction coupling the pair of said insertion walls to block the head cooling water channel, and the pair of section head cooling water channels communicate each other through the inter-insertion-wall head cooling water channel, the vertical wall is formed in a state of being present in a center region between the pair of said insertion walls, and the vertical wall is connected to and integrated with the insertion wall on the intake side out of the pair of said insertion walls.
2 . The cylinder head structure according to claim 1 , wherein an end of the vertical wall on a side not connected to the insertion wall is formed in a state of being present in a center region between the pair of said insertion walls.
3 . The cylinder head structure according to claim 1 , wherein an oblique hole water channel spanning the section head cooling water channel on one side and a bottom surface of the cylinder head bottom wall immediately below the vertical wall or on an other side is provided in a lower portion of the vertical wall, and cooling water on the intake side of the cylinder cooling water channel is introduced into the section head cooling water channel on one side which is arranged on the intake side of the head cooling water channel through the oblique hole water channel.
4 . The cylinder head structure according to claim 1 , wherein a reinforcing wall portion having an upward protrusion rib shape extending in a direction coupling the pair of said insertion walls, and a cooling water channel having a hole shape penetrating the reinforcing wall portion up and down are formed on the cylinder head bottom wall.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Section 371 of International Application No PCT/JP2023/013793, filed Apr. 3, 2023, which was published in the Japanese language on Jan. 4, 2024, under International Publication No. WO 2024/004308 A1, which claims priority under 35 U.S.C. § 119 (b) to Japanese Application No. 2022-105562, filed Jun. 30, 2022, the disclosures of each of which are incorporated herein by reference. TECHNICAL FIELD The present invention relates to a cylinder head assembled on a cylinder block by a plurality of fastening bolts. BACKGROUND ART It is common for a water-cooled multicylinder diesel engine or the like to adopt a structure in which cooling water discharged from a water pump is sent to a cooling water channel of a cylinder block (cylinder), and cooling water rises from a cooling water channel around each cylinder bore of the cylinder block into a cooling water channel of a cylinder head, as disclosed in Patent Document 1, for example. The cylinder block and the cylinder head are assembled across a gasket. However, since the width between the cylinder and the cylinder, that is, between the cylinder bores is narrow and the width of the gasket is also inevitably narrow, the sealing force of a combustion gas is likely to decrease. The part between the adjacent fastening bolts in the cylinder head has a hollow cross section due to the presence of the cooling water channel, and the rigidity is likely to decrease. In particular, between a pair of fastening bolts across adjacent cylinder bores in a cylinder block (see FIG. 4 of Patent Document 2), an axial force of the fastening bolts is less likely to be transmitted to the gasket through the cylinder head, and a gasket pressing force decreases, which may lead to a decrease in a sealing force. PRIOR ART DOCUMENTS Patent Documents Patent Document 1: Japanese Patent Application Laid-open No. 2003-97347Patent Document 2: Japanese Patent Application Laid-open No. 2015-108346 (FIG. 4) SUMMARY OF THE INVENTION Problems to be Solved by the Invention With recent improvement in performance, increasing the output of an engine without changing the interval between cylinders and the cylinder diameter naturally leads to an increase in combustion pressure. Therefore, it is necessary to further increase the sealing force between adjacent cylinders, but the above-described conventional technique has a limit, and further elaboration is required. An object of the present invention is to provide a cylinder head structure that can increase the rigidity of an inter-bore corresponding portion positioned above between adjacent cylinders in a cylinder head and easily improve the sealing force of the inter-bore corresponding portion when enhancing the sealing force between a cylinder block and the cylinder head to improve the output of an engine. Solutions to the Problems The present invention is characterized in that in a cylinder head structure, a cylinder head is assembled on a cylinder block by a plurality of fastening bolts,the cylinder head is provided with an insertion wall through which the fastening bolts arranged on both sides between adjacent cylinders in the cylinder block pass, a head upper wall coupling upper end portions of a pair of insertion walls, and a cylinder head bottom wall, anda cooling water channel surrounded by the pair of insertion walls, the head upper wall, and the cylinder head bottom wall is provided with a vertical wall spanning the head upper wall and the cylinder head bottom wall. Effects of the Invention According to the present invention, since the vertical wall is newly provided between the pair of insertion walls, the length between the pair of insertion walls is greatly shortened (the length of the beam when the head upper wall is analogized as a double cantilever beam is greatly reduced), and therefore the strength and rigidity of the inter-bore corresponding portion positioned above between adjacent cylinders in the cylinder head can be greatly improved. An axial force due to the fastening of the fastening bolts passing through the pair of insertion walls is guided not only through each insertion wall but also through the head upper wall and the cylinder head bottom wall, and the axial force is transmitted to the cylinder head as evenly as possible as compared with a conventional structure without a vertical wall. Therefore, the axial force guided between the pair of fastening bolts is substantively increased, and the sealing properties between a cylinder block and the cylinder head can be greatly improved. As a result, it is possible to provide a cylinder head structure that can increase the rigidity of an inter-bore corresponding portion positioned above between adjacent cylinders in a cylinder head and easily improve the sealing force of the inter-bore corresponding portion when enhancing the sealing force between a cylinder block and the cylinder head to improve the output of an engine. BRIEF DES