GB2504618A

GB2504618A - Dummy cylinder head used for machining cylinder block and method of use

Info

Publication number: GB2504618A
Application number: GB201313667A
Authority: GB
Inventors: Kazushi Sogawa; Junichi Nishiyama
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2012-08-02
Filing date: 2013-07-31
Publication date: 2014-02-05
Anticipated expiration: 2033-07-31
Also published as: JP5866264B2; GB2504618B; GB201313667D0; JP2014030877A

Abstract

A jig for machining a cylinder block comprising a plurality of through-holes 111 with first protruding portions as a bead 130 with non-contact regions 135 at both sides thereof in the Y direction across the centre of the through-holes. The non-contact regions are formed by providing a section where bead portions are not present or the bead portions are formed with a cut-out and the non-contact regions are not in contact with the cylinder block (200 figure2) at the time of bolting. Second protruding surfaces 140 take the form of shims that are located on the main body of the dummy head and outside the first protruding surfaces. Accordingly it is possible to accurately reproduce the deformation caused by bolting an actual cylinder head to the block with this dummy head. This allows the the cylinder bores (201 figure 2) to be machined under the stress caused by the dummy head and allows the shape of the bores to be much closer to the desired shape when the cylinder head is bolted to the block.

Description

CYLINDER BLOCK

BACKGROUND OF THE INVENTION <FIELD OF THE INVENTION>

The present invention relates to a jig for machining a cylinder block and a method of manufacturing the cylinder block, in which cylinder bores can be machined in a state where the cylinder block is deformed.

A cylinder block of an internal combustion engine is formed with a plurality of cylinder bores in which a piston is adapted to slide via oil film. A cylinder head is bolted to one surface of the cylinder block via gaskets. In order to suppress the sliding resistance of the piston when using the engine, the cylinder bores after bolting are required to have a cylindrical shape with a substantially perfect circular section.

However, when the cylinder bores are machined to have a substantially perfect circular section and then actual cylinder head is mounted to a mounting surface of the cylinder block, the shape of the cylinder bores is deformed by the mounting force. Accordingly, a technique has been suggested for machining the cylinder bores in a state where a dummy head as a jig for machining is bolted to the mounting surface.

Specifically, when the cylinder bores are machined, the dummy head is bolted to the mounting surface and deformation as in the case where the cylinder head is bolted occurs in the cylinder bores by the bolting force. Since the dummy head is formed with through-holes communicated with the cylinder bores, the deformed cylinder bores can be subjected to boring or honing through the through-holes so that the cylinder bores can be formed to have a substantially perfect circular section. After the cylinder bores are machined, the dummy head According to the invention of the aspect (6), it is possible to apply the surface Substantially circular bead portions 130 are formed on a lower surface 110b of the lines connecting the center of the through-hole 111 and the bolt insertion holes 112 adjacent in the X direction.

Next, a method for manufacturing the cylinder block will be described with reference to Fig. 4 and Fig. 5.

Fig. 4 is a sectional view taken along a line A-A in Fig. 1, showing a state before bolting where the dummy head is placed on the mounting surface of the cylinder block and Fig. 5 is a sectional view taken along a line A-A in Fig. 1, showing a state after bolting where the dummy head is placed on the mounting surface of the cylinder block. First, as shown in Fig. 4, the dummy head 100 is placed on the mounting surface of the cylinder block 200. At this time, the shim portions 140 are brought into contact with the mounting surface of the cylinder block 200 and the predetermined gap G is formed between the bead portions 130 and the peripheral edge portion of the cylinder bores 201.

Subsequently, as shown in Fig. 5, the bolts 120 are fastened to the bolt insertion holes 202 through the bolt insertion holes 112 and therefore the dummy head 100 is fixed to the cylinder block 200.

At this time, moment to the cylinder block 200 according to a bolt axial force of a pair of bolts 120 opposed to each other across the first imaginary line P can be applied to a portion (hereinafter, also referred to as “region between bolts”) between the pair of bolts 120 in the main body 110.

Since the shim portions 140 disposed on the outer peripheral side of the bolt insertion holes 112 are brought into contact with the mounting surface of the cylinder block 200 and the predetermined gap G is formed between the peripheral edge portion of the cylinder bores 201 and the bead portions 130 disposed on the peripheral edge portion of the through-hole 111, the moment to the cylinder block 200 according to the bolt axial force of the pair of bolts 120 can

Claims

1. A jig for machining a cylinder block, comprising: a main body, a plurality of through-holes which are formed on the main body and whose centers are arranged on a first imaginary line extending in an X direction when two directions perpendicular to each other are respectively denoted by the X direction and a Y direction, first protruding portions which are provided on a surface of the main body on the side of the cylinder block, disposed on the peripheral edge portion of the plurality of through-holes and brought into contact with the cylinder block by bolting and, second protruding portions which are provided on the surface of the main body on the side of the cylinder block and disposed outside the first protruding portions, wherein the jig for machining is bolted to one surface of the cylinder block when machining cylinder bores in a state where the cylinder block having the cylinder bores is deformed and, wherein at least one of the plurality of through-holes has non-contact regions at both sides thereof in the Y direction across the center of the through-hole, the non-contact regions are formed by providing a section where the first protruding portions are not present or the first protruding portions are formed with a cut-out and the non-contact regions are not in contact with the cylinder block at the time of bolting.

2. The jig for machining the cylinder block according to claim 1, wherein the first protruding portions have a substantially circular shape so as to surround an outer periphery of the through-holes and wherein each of the non-contact regions is provided in a range of 2% to 25% of the cylinder block and the non-contact regions are not brought into contact with the cylinder block.