Cylinder liner and cylinder liner and cylinder block assembly

Abstract

The problem to be solved by this invention is to provide a cylinder liner that can simultaneously achieve engine vibration suppression and engagement force. This problem is solved by a cylinder liner having a plurality of protrusions on its outer peripheral surface, wherein the outer peripheral surface of the cylinder liner has a thermally sprayed coating only on the tops of the protrusions; or, the plurality of protrusions have a thermally sprayed coating on their tops, and elastic members are filled between the plurality of protrusions.

Description

Technical Field

[0001] This invention relates to cylinder liners that improve the engagement force with the cylinder block. Furthermore, it relates to a joint between the cylinder liner and the cylinder block. Background Technology

[0002] In order to improve the engagement force between the cylinder liner and the cylinder block surrounding the cylinder liner, there is a technique to improve the sealing by forming a protrusion on the outer periphery of the cylinder liner (see Patent Document 1).

[0003] On the other hand, as a technology for suppressing engine vibration or noise caused by such vibration, there is, for example, a technology that provides a rebound portion between the engine cylinder block and the cylinder head (see Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: WO2021 / 255890

[0007] Patent Document 2: Japanese Patent Application Publication No. 2011-106385 Summary of the Invention

[0008] To suppress engine vibration, inventors have attempted to form a coating of elastomer on the surface of a cylinder liner with protrusions on its outer periphery for bonding with the cylinder block. However, while filling the spaces between the protrusions with elastomer significantly suppresses vibration when a coating is provided on the outer periphery of the cylinder liner, the bonding strength obtained by casting the spaces between the protrusions and the outer periphery of the cylinder liner together is lost, and the bonding force that could have been obtained by providing protrusions on the outer periphery of the cylinder liner is not achieved. This invention provides a cylinder liner that solves this problem.

[0009] In order to solve the above-mentioned problems, the inventors conducted research and discovered that the above-mentioned problems can be solved by having a thermal spray coating on the top of the protrusion in the cylinder liner with a protrusion on the outer peripheral surface.

[0010] One aspect of the present invention is a cylinder liner having multiple protrusions on its outer peripheral surface, wherein...

[0011] The outer peripheral surface of the cylinder liner has a thermal spray coating only on the top of the multiple protrusions.

[0012] Furthermore, another aspect of the present invention is a cylinder liner having a plurality of protrusions on its outer peripheral surface, wherein,

[0013] The plurality of protrusions have a thermally sprayed coating on their tops, and elastic members are filled between the plurality of protrusions. It should be noted that the thermally sprayed coating is preferably an aluminum alloy thermally sprayed coating.

[0014] In addition, another aspect of the present invention is a joint body consisting of a cylinder liner having a plurality of protrusions on its outer peripheral surface and a cylinder body joined to the cylinder liner, wherein the outer peripheral surface of the cylinder liner has a thermally sprayed coating only on the top of the plurality of protrusions.

[0015] Furthermore, another aspect of the present invention is a coupling body comprising a cylinder liner having a plurality of protrusions on its outer peripheral surface and a cylinder body coupled to the cylinder liner, wherein...

[0016] The plurality of protrusions have a thermally sprayed coating on their tops and are filled with elastic members between the plurality of protrusions.

[0017] Invention Effects

[0018] According to the present invention, a cylinder liner that can both suppress engine vibration and maintain the engagement force between the cylinder liner and the cylinder block can be provided. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of the enlarged protruding part on the outer circumference of the cylinder liner.

[0020] Figure 2 It is a cross-sectional schematic diagram of the joint portion of the joint body obtained by enlarging the connection between the cylinder liner and the cylinder block.

[0021] Figure 3 It is a cross-sectional schematic diagram of the joint portion of the joint body obtained by enlarging the connection between the cylinder liner and the cylinder block.

[0022] Figure 4 It is a microscope image (with a photograph as a substitute) of the joint portion of the cylinder liner and cylinder block obtained by joining them.

[0023] Figure 5 It is a microscope image (with a substitute photograph) of the joint portion of the cylinder liner and cylinder block obtained by joining them. Detailed Implementation

[0024] The present invention will now be described in detail, but the scope of the present invention is not limited by the following description.

[0025] One aspect of the invention is a cylinder liner with multiple protrusions on its outer peripheral surface. (Using...) Figure 1 Please provide a detailed explanation.

[0026] Figure 1 The diagram shows a cross-sectional view of a portion of the cylinder liner surface. The cylinder liner has multiple protrusions on its outer circumferential surface extending from the lower to the upper part of the diagram; from the viewpoint of the engagement force between the cylinder liner and the cylinder block, these protrusions are preferably necked.

[0027] The number and height of the protrusions are not particularly limited, but from the viewpoint of joint strength, the average height H of the protrusions is preferably 0.4 mm or more and 1.0 mm or less. It should be noted that the sectional view ( Figure 1 The height h of the protrusion shown is the distance between the bottom of the protrusion and the outermost circumference of the protrusion, but since it is not limited to the cross section passing through the maximum height of the protrusion, the average height H is used.

[0028] In addition, every 100mm of the cylinder liner surface 2 The number of protrusions is preferably 10 or more and less than 100, and the protrusions are preferably necked. It should be noted that the understanding of necked protrusions can be found, for example, in Patent Document 1.

[0029] <Total number of protrusions and average height of protrusions>

[0030] The number of protrusions and their average height (hereinafter referred to as "protrusion height") were measured using a 3D measuring instrument (KEYENCE VR-3000 series) at 25x magnification with a measurement field of view of 12mm × 9mm. The measured data were corrected for curvature using the analysis software included with the KEYENCE VR-3000 series. The correction condition was set to quadratic surface correction. Next, a reference plane was set. The reference plane was set to automatic setting based on region specification. The threshold was set to approximately 1 / 2 to 1 / 3 of the protrusion height; in this measurement, it was set to 0.25mm. Regions exceeding the threshold height were considered protrusions, and their number was defined as the protrusion count. This protrusion count was calculated as: the total number of protrusions within the field of view - the number of protrusions spanning the boundary of the field of view × 1 / 2. Based on the measured protrusion count and the field of view area, the total number of protrusions per unit area was calculated.

[0031] The height of each protrusion is set as the sum of the display range center, threshold, and maximum height. The display range center is a parameter set on the device side based on the characteristics of the cylinder liner to be measured, representing the height from the base surface of the protrusion to the reference surface. The threshold represents the height from the reference surface, and the maximum height represents the height from the threshold to the top of the protrusion. By reading the maximum height of each protrusion, the height of the protrusion can be measured, and the average height H of the protrusion can be calculated from its average value.

[0032] The height of the protrusion and the base surface vary depending on the direction of observation. Therefore, during the measurement, the entire field of view is measured by fixing the measurement direction in any given way.

[0033] This analysis is performed on four locations within a cylinder liner, and their average values ​​are calculated. These four locations are defined as two locations each, approximately 20 mm from both ends of the cylinder liner, and are set at positions offset from each other by approximately 90° at their ends.

[0034] Figure 2 This is a cross-sectional schematic diagram of the joint between the cylinder liner and the cylinder block connected to the cylinder liner, enlarged according to this method. Figure 2 The upper middle section is the cylinder block area. Figure 2 The lower middle section is the solid part of the cylinder liner.

[0035] In this type of cylinder liner, the thermally sprayed coating is only applied to the top of the protrusion, as shown by the shaded line in the figure. By applying the thermally sprayed coating to the top of the protrusion, the adhesion between the protrusion and the cylinder block is improved. Specifically, as... Figure 4 and Figure 5 As shown, the thermal spray coating on the protruding top enters the cylinder block and integrates with it, improving the bonding force between the cylinder liner and the cylinder block.

[0036] The thermal spray coating on the top of the protrusion will improve the bonding force between the cylinder liner and the cylinder block as long as the thermal spray coating is present on at least one top of the protrusion. However, from the point of view of strengthening the bonding force, it is preferable to have the thermal spray coating on the top of more than 50% of the protrusions, and even more preferably on the top of all the protrusions.

[0037] It should be noted that "only the protruding top" typically refers to... Figure 2 In the central left protrusion, within the area indicated by the vertical dotted line, use... Figure 3 To provide a more detailed explanation.

[0038] When the cylinder liner is cut in two sections along its axial direction, two cross-sections are created. In one of these cut surfaces, the average axial length of the thermal spray coating attached to the multiple protrusions in the cross-section must be at least 70% and less than 130% of the average of the maximum axial lengths of the protrusions in the cut surface. Furthermore, the length of the coating extending radially 100mm from the outer periphery... 2 In a range of multiple protrusions, the area of ​​the thermal spray coating only needs to be more than 70% of the area relative to the top of the protrusion.

[0039] Specifically, in Figure 3 In the sectional view shown, the axial length of the protrusion is represented by d1, d2, and d3. On the other hand, the axial length of the thermal spray coating is represented by ds1, ds2, and ds3. Even when the cylinder liner is cut along its axial direction, the entire protrusion is not cut at its center; therefore, the maximum diameter of the protrusion and the maximum length of the thermal spray coating cannot necessarily be determined in this section. There are... Figure 3 In the case where the length ds1 of the thermally sprayed coating on the left protrusion is longer than the axial length d1 of the protrusion, such as... Figure 3 In the case where the length ds2 of the thermally sprayed coating, such as the central protrusion, is shorter than the axial length d2 of the protrusion, for example... Figure 3The length ds3 of the thermal spray coating on the right-hand protrusion is almost the same as the axial length d3 of the protrusion. Therefore, the average length of the thermal spray coating attached to multiple protrusions only needs to be more than 70% and less than 130% of the average of the maximum axial lengths of the protrusions in the cross-section.

[0040] There are no particular limitations on the type of thermal spray coating; it can be appropriately selected according to the type of cylinder block. Specifically, examples include thermal spray coatings for iron alloys, aluminum alloys, and ceramic alloys. As an example, in the case where the cylinder block is formed from an aluminum die-casting, the thermal spray coating on the protruding top of the cylinder liner is an aluminum alloy thermal spray coating.

[0041] Furthermore, the thickness of the thermal spray coating is not particularly limited, and is usually 0.1 mm or more and 0.3 mm or less, preferably 0.15 mm or more and 0.25 mm or less.

[0042] There are no particular limitations on the spraying method used to form the thermal spray coating; any known method can be used. Specifically, plasma spraying, arc spraying, flame spraying, and gas spraying are examples. It should be noted that, in order to improve the adhesion between the cylinder liner protrusion and the thermal spray coating, the cylinder liner protrusion or the entire cylinder liner can also be preheated.

[0043] Furthermore, in this method, such as Figure 2 As shown, it is preferable to fill the spaces between the protrusions indicated by the single-dot dashed line with elastic members. By filling the spaces between the protrusions of the cylinder liner with elastic members, the elastic members absorb engine noise / vibration, thereby suppressing noise / vibration.

[0044] Even a small amount of elastic material filling the spaces between the protrusions in the cylinder liner will suppress engine noise / vibration. However, to maximize this effect, it is preferable to fill the spaces between the protrusions with the elastic material so that the outer circumferential surface of the cylinder liner is not exposed. More specifically, and more preferably, in a cross-sectional view of the cylinder liner including the protrusions, the area between adjacent protrusions, from the base of the protrusion to its apex, is considered (…). Figure 1 The base and apex of the protrusion (shown by dashed lines) are designated as the inter-protrusion region, where the elastic members have a high filling rate.

[0045] As an elastic component, any component capable of suppressing engine noise / vibration is acceptable; there are no particular limitations, and resin materials and rubber materials are examples. From a heat resistance perspective, silicone rubber is preferred as an elastic component.

[0046] As for the silicone rubber, a Shore A hardness of 25 to 50 is preferred. Furthermore, regarding the viscosity of the silicone rubber used for coating the outer peripheral surface of the cylinder liner, it is easier to apply in a liquid state before curing, ranging from a medium viscosity of 100 Pa·s to a low viscosity of 10 Pa·s or a paste-like state, and is therefore preferred.

[0047] The presence of elastic components between the cylinder liner protrusions and the filling ratio of these elastic components can be confirmed by cutting the cylinder liner or the joint between the cylinder liner and the cylinder block along the axial direction and observing the cross-section of the cylinder liner protrusions and the protrusions using a metal microscope.

[0048] The method for manufacturing cylinder liners in this solution is not particularly limited as long as it can produce a cylinder liner with multiple protrusions on its outer peripheral surface and at least a portion of the protrusions having elastic members. For example, a cylinder liner with protrusions can be manufactured using the method described in Patent Document 1.

[0049] There are no particular limitations on the method of filling the gaps between the protrusions of the cylinder liner with resin or rubber materials. As an example, an elastic member can be filled in to make the elastic member exist in the recess between the protrusions of the cylinder liner.

[0050] Furthermore, the method for manufacturing the assembly is not particularly limited and can be a known method. As an example, it may include the following steps: preparing a cylinder block mold; placing the cylinder liner of this embodiment into the prepared cylinder block mold; and allowing molten metal to flow into the cylinder block mold in which the cylinder liner is placed to form a cylinder block.

[0051] [Example]

[0052] The following examples illustrate the invention in more detail, but the scope of the invention is not limited to the following examples.

[0053] <Cylinder Liner Manufacturing>

[0054] A cast iron cylinder liner was manufactured according to the method described in Patent Document 1. The manufactured cylinder liner has an outer diameter (including the height of the protrusion) of 85 mm, an inner diameter of 74 mm (wall thickness of 5.5 mm), and an axial length of 130 mm.

[0055] In addition, the cylinder liner has multiple necked protrusions on its outer circumferential surface, with an average height of 0.7 mm per 100 mm. 2 The number of protrusions is 37.

[0056] <Example 1>

[0057] Next, silicone rubber A (viscosity 70 Pa·s) is filled onto the outer peripheral surface of the cylinder liner. After filling, an Al-Si thermal spray coating is formed on the top surface of the multiple protrusions. Subsequently, the cylinder liner is integrally cast into a cylinder block formed from an aluminum die-casting, forming a joint. An enlarged image of the joint between the cylinder liner and the cylinder block is shown below. Figure 4 The measured thickness of the thermally sprayed coating is approximately 0.11 mm.

[0058] It should be noted that silicone rubber was confirmed to be filling the spaces between the multiple protrusions.

[0059] <Example 2>

[0060] By filling with silicone rubber:B (paste), a joint was obtained in the same manner as in Example 1, except that the thickness of the Al-Si thermal spray coating was increased. An enlarged image of the joint between the cylinder liner and the cylinder block of the joint is shown below. Figure 5 The film thickness of the thermal spray coating was measured to be approximately 0.25 mm.

[0061] It should be noted that silicone rubber was confirmed to be filling the spaces between the multiple protrusions.

[0062] <Comparative Example 1>

[0063] The same bonding body was obtained as in Example 1, except that no Al-Si thermal spray coating was formed.

[0064] <Comparative Example 2>

[0065] The same bonding body was obtained as in Example 2, except that no Al-Si thermal spray coating was formed.

[0066] <Joint Strength Test>

[0067] The bonding strength of the obtained joints of Examples 1 to 2 and Comparative Examples 1 to 2 was determined by the following method.

[0068] Using a tensile testing machine (Shimadzu Corporation, universal testing machine: AG-5000E), one of the cylinder liner and cylinder block was fixed by clamping devices, and a tensile load was applied to the other in a direction approximately orthogonal to the joint surface of the two components. The tensile strength at which the two components peeled off was defined as the joint strength. The results are shown in Table 1. It should be noted that the results are the average of 15 evaluations performed on cylinder blocks manufactured by the same method, and are expressed as the relative strength when the strength of Comparative Example 2 is set to 1. It should be noted that Comparative Example 1 peeled off before the tensile load was applied.

[0069]

Claims

1. A cylinder liner having a plurality of protrusions on its outer peripheral surface, wherein, The outer peripheral surface of the cylinder liner has a thermal spray coating only on the top of the multiple protrusions.

2. A cylinder liner having multiple protrusions on its outer peripheral surface, wherein, The plurality of protrusions have a thermally sprayed coating on their tops and are filled with elastic members between the plurality of protrusions.

3. The cylinder liner according to claim 1, wherein, An elastic member is filled between the plurality of protrusions.

4. The cylinder liner according to claim 1 or 2, wherein, The thermal spray coating is an aluminum alloy thermal spray coating.

5. A coupling body comprising a cylinder liner having a plurality of protrusions on its outer peripheral surface and a cylinder block coupled to the cylinder liner, wherein, The outer peripheral surface of the cylinder liner has a thermal spray coating only on the top of the multiple protrusions.

6. A coupling body comprising a cylinder liner having a plurality of protrusions on its outer peripheral surface and a cylinder block coupled to the cylinder liner, wherein, The plurality of protrusions have a thermally sprayed coating on their tops and are filled with elastic members between the plurality of protrusions.

7. The joint according to claim 5, wherein, An elastic member is filled between the plurality of protrusions.

8. The joint according to claim 5 or 6, wherein, The thermal spray coating is an aluminum alloy thermal spray coating.

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