Cylinder head measuring tools

Abstract

To provide a measuring tool for a cylinder head which can accurately measure a shape of a bottom face of a recess which is formed on a surface of the cylinder head.SOLUTION: A measuring tool (1) for a cylinder head comprises: a base (10) having a cylinder part (11) rotatably fit into a recess (112) which is formed at the cylinder head (110), and covering a peripheral part of a bottom face (113) of the recess (112); a dial gauge (20); and a support part (30) for movably supporting the dial gauge (20) in an axial direction and a radial direction of the base (10). When the cylinder part (11) is fit into the recess (112), the base (10) is formed so that a reference part constituting a part of the bottom face (113) is exposed at the inside of the radial direction rather than an internal peripheral face of the cylinder part (11). A notch (13) extending to the outside of the radial direction from the internal peripheral face of the cylinder part (11), and making a part of the peripheral part exposed when the cylinder part (11) is fit into the recess (112), is formed at the base (10).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a measuring tool for a cylinder head. [Background technology]

[0002] Some conventional cylinder heads have a recess into which a cylinder liner is fitted (see, for example, Patent Document 1). A packing is disposed around the periphery of the bottom surface of the recess. The packing is sandwiched and held between the cylinder head and the cylinder liner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 5-64441 Summary of the Invention [Problem to be solved by the invention]

[0004] In a supercharged internal combustion engine, the higher the intake pressure, the greater the amount of drain generated when the air is cooled. This drain flows into the combustion chamber of the cylinder and reacts with the sulfur in the fuel, causing sulfuric acid corrosion, which can become a problem. This sulfuric acid corrosion occurs particularly noticeably around the periphery of the bottom surface of the recess where the packing is located, and is one of the causes of thickness reduction in the cylinder head at the periphery. When the cylinder head becomes thin at the periphery, the sealing ability of the packing deteriorates, and combustion gases can leak out from between the cylinder head and the cylinder liner.

[0005] To prevent this type of blow-by, the bottom surface of the cylinder is sometimes polished before use, a process known as rubbing. If the amount of thinning of the cylinder head at its periphery before rubbing exceeds a predetermined value, rubbing the cylinder head will result in an excessively thin cylinder head at its periphery after rubbing, which is undesirable from the standpoint of strength. For this reason, there is a demand for measuring the shape of the bottom surface of the recessed portion provided on the surface of the cylinder head. However, there is no means for accurately measuring the shape of the bottom surface of the recessed portion.

[0006] An object of the present disclosure is to provide a measuring tool for a cylinder head that can accurately measure the shape of the bottom surface of a recess provided on the surface of a cylinder head. [Means for solving the problem]

[0007] One aspect of the present invention provides a cylinder head measuring tool for measuring a disk-shaped recess provided in the surface of a cylinder head, the measuring tool measuring the shape of the bottom surface of the recess where an intake and exhaust port opens, the tool comprising: a base having a cylindrical portion that is rotatably fitted into the recess and covers the peripheral portion of the bottom surface; and a flange portion that is provided around the cylindrical portion and abuts against the surface surrounding the recess; a dial gauge having a measuring element that comes into contact with the bottom surface of the recess; and a support portion that is disposed on the base and supports the dial gauge movably in the axial and radial directions of the base, the base being formed so that when the cylindrical portion is fitted into the recess, a reference portion that constitutes a part of the bottom surface of the recess is exposed radially inward of the cylindrical portion, and the base is provided with a notch that extends radially outward from the inner peripheral surface of the cylindrical portion and that exposes a part of the peripheral portion of the bottom surface of the recess when the cylindrical portion is fitted into the recess.

[0008] According to this configuration, the base is provided with a notch that extends radially outward from the inner peripheral surface of the cylindrical portion and exposes a portion of the peripheral edge of the bottom surface of the recess when the cylindrical portion is fitted into the recess. This allows the probe of the dial gauge to pass through the notch and move between the reference portion exposed on the radially inner side of the cylindrical portion and the peripheral edge. This eliminates the need to move the dial gauge up and down when measuring dimensional changes between the reference portion and the peripheral edge. This allows for accurate measurement of the shape of the bottom surface of the recess provided on the surface of the cylinder head.

[0009] With this configuration, the cylindrical portion is rotatably fitted into the recess, and by rotating the base relative to the cylinder head while the dial gauge probe is in contact with the peripheral edge of the bottom surface, it is possible to measure the surface shape at multiple positions on the same circumference of the peripheral edge.

[0010] In one embodiment, when the cylindrical portion is fitted into the recess, the cylindrical portion and the bottom surface are arranged with a gap therebetween.

[0011] The shape of a portion of the bottom surface of a recess in a cylinder head may change due to corrosion. Therefore, when the cylindrical portion of the base and the bottom surface of the cylinder head are in contact with each other, the base may tilt or rattle, making it difficult to accurately measure the shape of the bottom surface of the recess. In the above embodiment, the cylindrical portion of the base and the bottom surface of the cylinder head are arranged with a gap between them. Therefore, changes in the shape of the bottom surface of the cylinder head due to corrosion do not affect the measurement accuracy of the shape of the bottom surface of the recess. As a result, the measurement accuracy of the shape of the bottom surface of a recess provided on the surface of the cylinder head can be improved.

[0012] In one embodiment, the support is removably securable to the base.

[0013] In the above embodiment, the support portion can be removably fixed to the base. Therefore, by fixing the support portion to the base and measuring the shape of the bottom surface of the recess, the shape of the bottom surface of the recess provided in the surface of the cylinder head can be measured with high accuracy. On the other hand, when moving the probe, the fixation of the support portion to the base can be released, allowing the probe to be easily moved.

[0014] In one embodiment, one end of a cylinder liner is fitted into the recess. [Effects of the Invention]

[0015] According to the present invention, it is possible to improve the measurement accuracy of the shape of the bottom surface of a recess provided on the surface of a cylinder head. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a longitudinal cross-sectional view of a cylinder according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a bottom view of the cylinder head according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a perspective view of a cylinder head measuring tool according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a top view of the cylinder head measurement tool in FIG. 3. [Figure 5] 5 is a cross-sectional view taken along line VV in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0018] (cylinder head) First, a cylinder head, which is a measurement object according to the present disclosure, will be described with reference to Figures 1 to 3. Figure 1 is a vertical cross-sectional view of a cylinder 100 according to the present embodiment. The cylinder 100 is a cylinder used in a large internal combustion engine such as a ship engine.

[0019] Referring to FIG. 1, the cylinder 100 includes a cylinder head 110, a cylindrical cylinder liner 120, and an annular packing 130. The cylinder liner 120 is fitted into a recess 112 (described later) provided in the cylinder head 110. The packing 130 is disposed in the recess 112 and is held between the cylinder head 110 and the cylinder liner 120. In this embodiment, one cylinder head 110 is attached to one cylinder liner 120. The cylinder head 110, the cylinder liner 120, and a piston (not shown) form a combustion chamber. For clarity, FIG. 1 illustrates only the cylinder head 110, the cylinder liner 120, and the packing 130 of the cylinder 100, and does not illustrate other components of the cylinder 100 (e.g., a cylinder block).

[0020] 2 is a bottom view of the cylinder head 110. Referring to FIGS. 1 and 2, the cylinder head 110 has a lower end surface 111 that is disposed opposite the cylinder liner 120. This lower end surface 111 is provided with a recess 112. The lower end surface 111 of the cylinder head 110 of this embodiment is an example of a surface of a cylinder head according to the present disclosure.

[0021] As described above, the cylinder liner 120 is fitted into the recess 112. The recess 112 is recessed upward from the lower end surface 111 of the cylinder head 110. In other words, the recess 112 is recessed from the lower end surface 111 of the cylinder head 110 on the side opposite to the cylinder liner 120.

[0022] The recess 112 is disk-shaped. In other words, the recess 112 is a portion that defines a disk-shaped space. Specifically, the recess 112 has a circular bottom surface 113 and a cylindrical connecting surface 114 that rises from the outer periphery of the bottom surface 113 and connects the bottom surface 113 and the lower end surface 111. The inner diameter of the connecting surface 114 is slightly larger than the outer diameter of the upper end of the cylinder liner 120.

[0023] The bottom surface 113 defines the upper side of the combustion chamber. As shown in Fig. 2, the bottom surface 113 is provided with four intake and exhaust ports 115 and a fuel injection port 116. The fuel injection port 116 is disposed in the center of the bottom surface 113. The four intake and exhaust ports 115 are disposed at equal intervals along the circumferential direction of the central axis C112 of the recess 112.

[0024] 2, the bottom surface 113 has a peripheral portion 113a and a reference portion 113b. For clarity, the peripheral portion 113a and the reference portion 113b are shown with hatched lines in FIG.

[0025] The peripheral edge portion 113a is an annular region located on the outer periphery of the bottom surface 113. When the cylinder head 110 and the cylinder liner 120 are connected, a packing 130 (shown in FIG. 1) is disposed in the peripheral edge portion 113a. A circular first groove 117 and a circular second groove 118 are also formed in the peripheral edge portion 113a. The first groove 117 and the second groove 118 are concentric circles centered on the central axis C112. In the radial direction of the central axis C112, the first groove 117 is disposed more inward than the second groove 118.

[0026] The reference portion 113b is a region located radially inward of the peripheral portion 113a in the radial direction of the central axis C112. The thickness of the cylinder head 110 at the reference portion 113b is equal to the thickness of the cylinder head 110 at the peripheral portion 113a when no thinning occurs in the cylinder head 110.

[0027] (Cylinder head measuring tool) FIG. 3 is a perspective view of a cylinder head measurement tool 1 (hereinafter referred to as the measurement tool 1) according to this embodiment. FIG. 4 is a view from above of the measurement tool 1 attached to a cylinder head 110. FIG. 5 is a cross-sectional view taken along line VV in FIG. 4. As shown in FIG. 3, when using the measurement tool 1, the cylinder head 110 is positioned so that the lower end surface 111 of the cylinder head 110 faces upward, and the measurement tool 1 is placed on the cylinder head 110. In FIGS. 4 and 5, the dial gauge 20 and stand 30 of the measurement tool 1 are not shown. For clarity, in FIG. 4, the peripheral edge 113a (only the portion exposed from a cutout 13, which will be described later) and the reference portion 113b are indicated by hatching.

[0028] The measuring tool 1 measures a recess 112 provided in a lower end surface 111 of a cylinder head 110, and measures the shape of a bottom surface 113 of the recess 112. Referring to FIG. 3 , the measuring tool 1 includes a base 10, a dial gauge 20, and a stand 30.

[0029] 5, the base 10 includes a cylindrical portion 11 and a flange portion 12. The base 10 is made of a ferromagnetic material, such as iron.

[0030] The cylindrical portion 11 is fitted into the recess 112 of the cylinder head 110. More specifically, the cylindrical portion 11 is fitted into the recess 112 by a spigot joint. In other words, the cylindrical portion 11 and the recess 112 are fitted together with their centers aligned. Specifically, the cylindrical portion 11 and the recess 112 are fitted together with the central axis C11 of the cylindrical portion 11 and the central axis C112 of the recess 112 coinciding. When fitted into the recess 112, the cylindrical portion 11 is rotatable around the central axis C11 of the cylindrical portion 11.

[0031] As shown in FIG. 4, when the tubular portion 11 is fitted into the recess 112 (shown in FIG. 5), the tubular portion 11 covers the peripheral edge portion 113a. On the other hand, when the tubular portion 11 is fitted into the recess 112, a reference portion 113b of the bottom surface 113 is exposed radially inward of the inner circumferential surface 11a of the tubular portion 11. As shown in FIG. 5, when the tubular portion 11 is fitted into the recess 112, the tubular portion 11 and the bottom surface 113 are arranged with a gap between them in the up-down direction. In other words, when the tubular portion 11 is fitted into the recess 112, the lower end of the tubular portion 11 does not contact the bottom surface 113.

[0032] As shown in FIG. 5 , the flange portion 12 is provided around the tubular portion 11. The flange portion 12 protrudes radially outward from the outer peripheral surface of the tubular portion 11. The flange portion 12 is annular. The flange portion 12 abuts against and contacts a portion of the lower end surface 111 of the cylinder head 110 that surrounds the recess 112. In this way, the base 10 is supported by the cylinder head 110.

[0033] The base 10 is provided with a cutout 13. The cutout 13 extends radially outward from the inner peripheral surface 11a of the tubular portion 11, and exposes a portion of the peripheral edge 113a of the bottom surface 113 when the tubular portion 11 is fitted into the recess 112. The cutout 13 passes through the base 10 in the up-down direction. The radially inner end of the cutout 13 is open. The radially outer end of the cutout 13 terminates inside the base 10 (more specifically, at the flange portion 12).

[0034] Seven holes 14 are provided in the base 10. The notches 13 and the seven holes 14 are arranged at equal intervals in the circumferential direction around the central axis C11 of the cylindrical portion 11. The seven holes 14 are arranged on the same circle around the central axis C11 of the cylindrical portion 11.

[0035] 3, the dial gauge 20 is a spindle-type dial gauge. The dial gauge 20 includes a measuring element 21 that contacts the bottom surface 113, and a display unit 22. The dial gauge 20 is not limited to a spindle-type dial gauge, and may be another type of dial gauge, such as a lever-type dial gauge.

[0036] The stand 30 supports the dial gauge 20 so that it can move in the axial direction (i.e., the up-and-down direction) and radial direction of the base 10. The stand 30 includes a fixed portion 31, a first shaft portion 32, and a second shaft portion 33. The fixed portion 31 is cubic in shape. A permanent magnet is disposed within the fixed portion 31. By operating a selector switch 31a disposed on the side of the fixed portion 31, the magnetic force acting on the bottom surface of the fixed portion 31 can be turned on or off. This allows the stand 30 to be removably fixed to the base 10. The stand 30 of this embodiment is an example of a support portion according to the present disclosure.

[0037] The first shaft portion 32 extends in the vertical direction. The lower end of the first shaft portion 32 is connected to the fixed portion 31.

[0038] One end of the second shaft portion 33 is connected to the first shaft portion 32. The other end of the second shaft portion 33 is connected to the dial gauge 20. The second shaft portion 33 is movable in the up and down direction along the first shaft portion 32. The second shaft portion 33 is rotatable around the first shaft portion 32. This allows the dial gauge 20 to move in the axial direction (i.e., the up and down direction) and radial direction of the base 10.

[0039] (How to use measuring tools for cylinder heads) A method of using the measuring tool 1 according to this embodiment will be described below.

[0040] First, as shown in Fig. 3, the base 10 is attached to the cylinder head 110. Specifically, the base 10 is attached to the cylinder head 110 so that the cylindrical portion 11 of the base 10 fits into the recessed portion 112 of the cylinder head 110. At this time, markings MA (only two positions are shown in Fig. 3) are made at positions of the cylinder head 110 corresponding to the seven holes 14 provided in the base 10.

[0041] Next, the stand 30 and the dial gauge 20 are placed on the base 10. At this time, the dial gauge 20 is placed so that the contact point 21 of the dial gauge 20 contacts a position (hereinafter referred to as the reference position R) within the reference portion 113b (shown in FIG. 4).

[0042] Next, the changeover switch 31a of the fixing part 31 is operated to apply a magnetic force to the bottom surface of the fixing part 31, thereby fixing the stand 30 to the base 10. In this state, the dial gauge 20 is set to the zero point.

[0043] Next, the selector switch 31a of the fixing portion 31 is operated to turn off the magnetic force acting on the bottom surface of the fixing portion 31, thereby releasing the fixing of the stand 30 to the base 10. In this state, the stand 30 is moved radially outward along the surface of the base 10, and the probe 21 is moved from the reference position R to a position within the circumferential edge 113a (hereinafter referred to as measurement position M). For example, measurement position M1, which is radially inward of the first groove 117 in the circumferential edge 113a, may be used as measurement position M. Alternatively, measurement position M2, which is located between the first groove 117 and the second groove 118 in the circumferential edge 113a, may be used as measurement position M2.

[0044] After obtaining a measurement value at measurement position M, the marking MA is used to rotate the base 10 45° around the central axis C11 of the cylindrical portion 11, and measurement values ​​are obtained. Thereafter, the base 10 is similarly rotated in the same direction by 45° each time, and measurement values ​​are obtained at a total of eight positions.

[0045] The measuring tool 1 according to the present disclosure has the following functions.

[0046] The base 10 is provided with a notch 13 that extends radially outward from the inner circumferential surface 11a of the cylindrical portion 11 and exposes a portion of the peripheral edge 113a of the bottom surface 113 of the recess 112 when the cylindrical portion 11 is fitted into the recess 112. This allows the probe 21 of the dial gauge 20 to pass through the notch 13 and move reciprocally between the reference portion 113b and the peripheral edge 113a exposed on the radially inner side of the cylindrical portion 11. This makes it unnecessary to move the dial gauge 20 up and down when measuring the dimensional change between the reference portion 113b and the peripheral edge 113a. This makes it possible to accurately measure the shape of the bottom surface 113 of the recess 112 provided in the lower end surface 111 of the cylinder head 110.

[0047] The cylindrical portion 11 is rotatably fitted into the recess 112. Therefore, by rotating the base 10 relative to the cylinder head 110 while the probe 21 of the dial gauge 20 is in contact with the peripheral portion 113a of the bottom surface 113, the surface shape of the peripheral portion 113a can be measured at multiple positions on the same circumference of the peripheral portion 113a.

[0048] The shape of a portion of the bottom surface 113 of the cylinder head 110 may change due to corrosion. Therefore, when the cylindrical portion 11 of the base 10 and the bottom surface 113 of the cylinder head 110 are in contact with each other, the base 10 may tilt or rattle, making it difficult to accurately measure the shape of the bottom surface 113 of the recess 112. In the above embodiment, the cylindrical portion 11 of the base 10 and the bottom surface 113 of the cylinder head 110 are spaced apart. Therefore, changes in the shape of the bottom surface 113 of the cylinder head 110 due to corrosion do not affect the accuracy of measuring the shape of the bottom surface 113 of the recess 112. As a result, the accuracy of measuring the shape of the bottom surface 113 of the recess 112 provided in the lower end surface 111 of the cylinder head 110 can be improved.

[0049] The stand 30 can be removably fixed to the base 10. Therefore, by fixing the stand 30 to the base 10 and measuring the shape of the bottom surface 113 of the recess 112, it is possible to accurately measure the shape of the bottom surface 113 of the recess 112. On the other hand, when moving the measuring point 21, the measuring point 21 can be easily moved by releasing the stand 30 from being fixed to the base 10.

[0050] Although specific embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. [Explanation of symbols]

[0051] 1. Measuring tools (cylinder head measuring tools) 10 base 11 Cylinder part 11a Inner surface 12 Flange 13 Cutout 14 holes 20 Dial Gauge 21 Probe 22 Display section 30 Stand (support part) 31 Fixed part 31a Changeover switch 32 First shaft 33 Second shaft 100 cylinders 110 Cylinder head 111 Lower end surface 112 recess 113 bottom 113a Periphery 113b Reference section 114 Connection Surface 115 Intake and exhaust ports 116 Fuel injection port 120 Cylinder liner 130 Gasket

Claims

1. A measuring tool for a cylinder head, which measures a disk-shaped recess provided on a surface of a cylinder head and measures the shape of a bottom surface of the recess where an intake and exhaust port opens, a base including a cylindrical portion rotatably fitted in the recess and covering the peripheral edge of the bottom surface, and a flange portion provided around the cylindrical portion and in contact with a surface surrounding the recess; a dial gauge having a probe that contacts the bottom surface; a support portion that is disposed on the base and supports the dial gauge movably in the axial and radial directions of the base; Equipped with the base is formed such that, when the cylindrical portion is fitted into the recess, a reference portion constituting a part of the bottom surface is exposed radially inward from an inner circumferential surface of the cylindrical portion, the base is provided with a notch that extends radially outward from an inner circumferential surface of the cylindrical portion and exposes a portion of the peripheral edge portion when the cylindrical portion is fitted into the recess, The measuring tool for a cylinder head, wherein the measuring element is movable between the reference portion and the peripheral portion through the notch.

2. The cylinder head measuring tool according to claim 1 , wherein when the cylindrical portion is fitted into the recess, the cylindrical portion and the bottom surface are disposed with a gap therebetween.

3. The cylinder head measuring tool according to claim 1 or 2, wherein the support portion is removably fixed to the base.

4. The cylinder head measuring tool according to claim 1 , wherein one end of a cylinder liner is fitted into the recess.

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