Cylinder liner, and joint between the cylinder liner and the cylinder block
A cylinder liner with protrusions and a silicone rubber coating between them provides a cylinder liner and cylinder block joint that effectively suppresses engine vibrations and noise, addressing the inadequacies of existing coatings that withstand the heat of aluminum die casting.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TEIKOKU PISTON RING CO LTD
- Filing Date
- 2024-11-25
- Publication Date
- 2026-06-04
AI Technical Summary
Existing engine vibration suppression techniques are inadequate for internal combustion engines, particularly in comparison to electric vehicles, and existing coatings on cylinder liners fail to withstand the heat of aluminum die casting, leading to loss of vibration suppression effect.
A cylinder liner with protrusions on its outer surface and a resin or rubber coating in the recesses between these protrusions, preferably using silicone rubber, is used to create a joint with the cylinder block, ensuring the coating remains intact post-casting and effectively suppresses engine vibrations and noise.
The solution provides a cylinder liner and joint that significantly suppresses engine vibrations and noise, with a damping ratio improvement of up to 1.9 times compared to uncoated systems, demonstrating effective vibration and noise reduction.
Smart Images
Figure 2026091469000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a joined body of a cylinder liner and a cylinder block capable of suppressing engine vibration.
Background Art
[0002] As a technique for suppressing engine vibration, for example, there is a technique of providing an elastic repulsion part between a cylinder block and a cylinder head of an engine (see Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Compared with an EV using a motor, the vibration of an engine is large, and there is still room for further improvement in suppressing engine vibration. The present invention has been found under such circumstances, and provides a new cylinder liner for suppressing engine vibration.
Means for Solving the Problems
[0005] In order to solve the above problems, the inventors of the present invention studied means for suppressing vibration in an engine. Then, focusing on the cylinder that slides with the piston, the study was advanced, and an attempt was made to provide a coating made of a resin material between the cylinder liner cast in the cylinder block and the cylinder block. However, the coating on the surface of the cylinder liner disappeared due to heat such as aluminum die casting and was replaced by an aluminum alloy, and the vibration suppression effect could not be obtained.
[0006] The inventors further investigated how to leave a heat-resistant coating made of resin or rubber material on the cylinder liner even after casting, and found that by using a cylinder liner with protrusions on its outer surface, the coating can be left in the recesses between the protrusions even after casting, which is useful for counteracting engine vibrations.
[0007] One embodiment of the present invention is a joint comprising a cylinder block and a cylinder liner cast within the cylinder block, The cylinder liner has a plurality of protrusions on its outer circumference, The joint has a coating made of a resin material or a rubber material between the cylinder liner and the cylinder block.
[0008] In a cross-section of the cylinder liner in the radial direction perpendicular to the axial direction of the cylinder liner, it is preferable that the coating occupies 50% or more of the area of the recesses formed between the protrusions of the cylinder liner, and that the recesses formed between the protrusions of the cylinder liner have a coating with a thickness of 0.2 mm or more, and that there are cross-sections with the coating in the recesses formed between the protrusions of the cylinder liner over the entire outer surface, and it is preferable that the recesses formed between the protrusions of the cylinder liner have the coating in any cross-section in the axial direction of the cylinder liner. Furthermore, it is preferable that the resin material or rubber material is silicone rubber.
[0009] Another embodiment of the present invention is a cylinder liner cast into an aluminum alloy cylinder block, wherein the cylinder liner extends from the central axis side to the outer circumference side. This is a cylinder liner that has multiple protrusions and has a coating made of resin or rubber material in the recesses formed between the multiple protrusions. [Effects of the Invention]
[0010] The present invention provides a cylinder liner and a joint between the cylinder liner and the cylinder block that can suppress engine vibration. Furthermore, it can provide a cylinder liner and joint that can also reduce engine noise. [Brief explanation of the drawing]
[0011] [Figure 1] This is a schematic cross-sectional view showing an enlarged view of the protruding portion on the outer surface of the cylinder liner. [Figure 2] This is an example of a magnified microscope image of the joint portion of a joint where a cylinder liner and a cylinder block are joined (photograph used as a substitute for a drawing). [Figure 3] This is an example of a magnified microscope image of the joint portion of a joint where a cylinder liner and a cylinder block are joined (photograph used as a substitute for a drawing). [Figure 4] This figure shows a casting block-like product manufactured using the hammering test described in the example. [Figure 5] This graph shows the results of the hammering test in Example 1. [Figure 6] This graph shows the hammering test results for Example 2. [Figure 7] This graph shows the hammering test results for Comparative Example 1. [Modes for carrying out the invention]
[0012] The present invention will be described in detail below, but its scope is not limited by the following description. One embodiment of the present invention is a joint comprising a cylinder block and a cylinder liner having a plurality of protrusions on its outer circumferential surface, which is cast into the cylinder block. Another embodiment is a cylinder liner cast into an aluminum alloy cylinder block, wherein the cylinder liner has a plurality of protrusions extending from the central axis side to the outer circumference, and the recesses formed between the plurality of protrusions have a coating made of a resin material or a rubber material. First, the cylinder liner will be described in detail using FIGS. 1 and 2.
[0013] FIG. 1 shows a schematic cross-sectional view of the outer peripheral surface portion of a cross-section in the radial direction of the cylinder liner orthogonal to the axial direction of the cylinder liner. On the outer peripheral surface of the cylinder liner, there are a plurality of protrusions from the lower part to the upper part in the figure, that is, from the solid part of the cylinder liner toward the outermost peripheral surface of the protrusion. From the viewpoint of the bonding force between the cylinder liner and the cylinder block, it is preferable that the protrusions are constricted.
[0014] The number and height of the protrusions are not particularly limited, but from the viewpoint of bonding strength, it is preferable that the average height H of the protrusions is 0.4 mm or more and 1.0 mm or less. Note that the protrusion height h shown in the cross-sectional view (FIG. 1) is the distance between the bottom of the protrusion and the outermost peripheral surface of the protrusion, but since it is not necessarily a cross-section passing through the maximum height portion of the protrusion, the average height H is used. Also, the number of protrusions per 100 mm 2 of the surface of the cylinder liner is usually preferably 10 or more and 100 or less, and it is preferable that the protrusions are constricted. For the understanding of the constricted protrusions, for example, reference can be made to WO2021 / 255890.
[0015] <Total number of protrusions and average height of protrusions> The number and average height of the protrusions (hereinafter also simply referred to as "height of the protrusions") were measured with a 3D measuring instrument (Keyence VR-3000 series) at a magnification of 25 times and a measurement field range of 12 mm × 9 mm. The measured data was curvature-corrected with the analysis software attached to the Keyence VR-3000 series. The correction condition was quadratic surface correction. Next, a reference plane was set. The reference plane was set automatically by region designation. The threshold value was set to about 1 / 2 to 1 / 3 of the protrusion height, and was 0.25 mm at the time of this measurement. The height region exceeding the threshold value was regarded as a protrusion, and the number thereof was regarded as the number of protrusions. This number of protrusions was calculated as the total number of protrusions existing in the visual field - the number of protrusions crossing the boundary of the visual field × 1 / 2. From the measured number of protrusions and the visual field area, the total number of protrusions per unit area was obtained. The height of each protrusion was set as the total value of the display range center + threshold value + maximum height. The display range center is a parameter set on the device side according to the properties of the cylinder liner to be measured, and represents the height from the base surface of the protrusion to the reference surface. The threshold value represents the height from the reference surface, and the maximum height represents the height from the threshold value to the tip 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 was obtained from the average value thereof. Since the height and base surface of the protrusion vary depending on the observation direction due to the shape of the protrusion, it was fixed in the arbitrarily determined measurement direction during measurement, and all of the measurement visual field range was measured. This analysis was performed at four locations on one cylinder liner, and the average value thereof was obtained. These four locations were two locations each at positions approximately 20 mm from both ends of the cylinder liner, and were positions shifted from each other by approximately 90° at both ends thereof.
[0016] Figure 2 is an enlarged microscope image of a joint portion where a cylinder block and a cylinder liner cast in the cylinder block are joined in the joined body of this embodiment. The upper part in Figure 2 is a region of the cylinder block portion made of die-cast aluminum (aluminum alloy), and the lower part in Figure 2 is a region of the cylinder liner portion. Further, the thinly displayed portions existing in the recesses formed on the left and right of the protrusions of the cylinder liner are coatings (silicone rubber). Thus, since the coating exists in the recesses between the protrusions of the cylinder liner, the coating can absorb the noise and vibration of the engine and suppress the noise and vibration.
[0017] The effect of suppressing the noise and vibration of the engine is exhibited if there is even a small amount of coating between the protrusions of the cylinder liner. However, in order to make the effect sufficient, it is preferable that the coating exists so that the outer peripheral surface of the cylinder liner in the recess between the protrusions is not exposed.
[0018] More specifically, in a radial cross-section perpendicular to the axial direction of the cylinder liner including the protrusions, the region between adjacent protrusions, from the bottom of the protrusion to the outermost surface of the protrusion (shown by a dotted line in Figure 1 between the bottom of the protrusion and the outermost surface of the protrusion), is considered a recess formed between the protrusions. Preferably, the coating covers 50% or more of the area of this recess, and more preferably 75% or more. There is no particular upper limit, but the coating may evaporate due to the heat generated when casting the cylinder liner or may come off due to cutting and polishing for cross-sectional observation, so it may be 90% or less.
[0019] The resin or rubber material for the coating is not particularly limited as long as it can suppress engine noise and vibration. Resin materials such as PEEK, polyimide, phenol, and silicone resin, and rubber materials such as silicone rubber can be used, but silicone rubber is preferred from the viewpoint of heat resistance and vibration damping. The heat resistance temperature of the resin or rubber material should preferably be 250°C or higher, considering the aluminum die casting. For silicone rubber, a Shore A (Durometer A / Type A) hardness of 25 to 50 is preferred. . When applying silicone rubber to the outer circumference of a cylinder liner, a viscosity of 100 Pa·s (medium viscosity) to 10 Pa·s (low viscosity) or paste-like consistency is preferable for its superior workability in its liquid state before curing.
[0020] The fact that the recesses between the cylinder liner protrusions are filled with coating, and the coating filling rate in the recesses, is determined by cutting the cylinder liner, or the joint between the cylinder liner and the cylinder block, in a radial direction perpendicular to the axial direction and using a microscope (Keyence VHX). Using the VHX-8000 series, measurements are taken at a magnification of 150x with a field of view of 3.6 mm (circumferential direction) x 1.1 mm (radial direction). The measured data is analyzed using the analysis software included with the Keyence VHX-8000 series to determine the area. The area obtained by subtracting the area of the cylinder block and the cylinder liner body from the total field of view can be determined as the area of the recess between the protrusions. Furthermore, after determining the area of the coated portion, the filling rate can be determined from the relationship between the coated portion area and the area of the recess between the protrusions. This analysis is performed at four locations in the radial cross-section perpendicular to the axial direction of a single cylinder liner, and the average value is taken as the measurement.
[0021] A specific measurement example will be explained using Figure 3. Figure 3 is an example of a magnified microscope image of the joint portion where a cylinder block and a cylinder liner cast into the cylinder block are joined, according to this embodiment. In this image, the coating thickness in the recesses between the cylinder liner protrusions and the coating filling rate in the recesses were actually measured using the method described above. As a result, the coating filling rate in the recesses was 83%, and the coating thickness in the recesses was measured at a difference of 0.5 mm between the smallest diameter part of the cylinder liner where no coating was attached and the outermost diameter part of the coated part at the same location (distance indicated by the arrow in Figure 3). The thickness in other parts ranged from 0.2 mm to 0.7 mm.
[0022] The method for manufacturing the cylinder liner of this embodiment is not particularly limited, as long as it can produce a cylinder liner having a plurality of protrusions on its outer circumferential surface and a coating on at least a portion of the spaces between the plurality of protrusions. A cylinder liner having protrusions can be manufactured, for example, by the method described in WO2021 / 255890.
[0023] The method for providing a coating in the recesses between the protrusions of the cylinder liner is not particularly limited; for example, a coating can be provided in the recesses between the protrusions of the cylinder liner by applying a coating agent. Furthermore, the coating area on the cylinder liner may be adjusted to exclude a portion in the axial direction or a portion in the circumferential direction, taking into consideration the connection with the engine block and cooling.
[0024] Furthermore, the method for manufacturing the joint is not particularly limited and known methods can be employed. For example, the method may include the steps of preparing a mold for a cylinder block, placing the cylinder liner of this embodiment into the prepared mold for a cylinder block, and pouring molten metal into the mold for a cylinder block in which the cylinder liner is placed to form a cylinder block.
[0025] The cylinder liner and joint in this embodiment have an excellent vibration suppression effect. Specifically, in damping ratio measurements by hammering, the vibration damping is 1.3 times or more, preferably 1.9 times or more, compared to the case without the coating. Damping ratio measurement by hammering can be performed by casting the cylinder liner in aluminum die-cast, boring it to the final inner diameter, exciting it with an impulse hammer, detecting the resulting vibration with an acceleration sensor, and measuring it with an FFT analyzer. [Examples]
[0026] The present invention will be described in detail below with reference to experimental examples, but the present invention is not limited by the results of the following experimental examples. <Manufacturing of cylinder liners> Cylinder liners for Examples 1 and 2 and Comparative Example 1 were manufactured in accordance with the description in WO2021 / 255890. The number of protrusions (100mm) of the manufactured cylinder liners was... 2 Table 1 shows the hits and average protrusion heights.
[0027] [Table 1]
[0028] <Coating applied> Next, the manufactured cylinder liners were coated. The silicone rubber used for the coating was a commercially available product with a heat resistance of 250°C or higher. Example 1 used silicone rubber A (viscosity: 70 Pa·s, hardness: A26 on durometer A), and Example 2 used silicone rubber B (viscosity: unmeasurable (paste-like), hardness: A45 on durometer A). Silicone rubber was applied to the outer surface of the cylinder liner, and excess silicone rubber was removed by placing a commercially available spatula against the top surface of the protrusions on the outer surface of the cylinder liner. After the entire circumference of the cylinder liner was coated with silicone rubber, it was allowed to air dry.
[0029] <Hammering Test> Using a cylinder liner coated with silicone rubber, a block-like product similar to the one shown in Figure 4 was created by connecting two cylinder liners using aluminum die casting. Next, an acceleration sensor was installed on the inner surface of the cylinder liner, and the outside of the manufactured cast block-like product was struck with an impulse hammer to induce vibration. The vibration damping was then measured using the acceleration sensor. The hammering test results for the cylinder liners of Examples 1 to 3 are shown in Figures 5 to 7, respectively. Table 2 also shows the damping ratios of the hammering test results for Example 1, Example 2, and Comparative Example 1. Compared to aluminum casting without coating (Comparative Example 1), the aluminum casting with coating (Examples) showed an effect of 1.9 times (Example 1) to 1.3 times (Example 2).
[0030] [Table 2]
Claims
1. A joint comprising a cylinder block and a cylinder liner cast within the cylinder block, The cylinder liner has a plurality of protrusions on its outer circumference, A joint having a coating made of a resin material or a rubber material between the cylinder liner and the cylinder block.
2. The joint according to claim 1, wherein, in a cross-section of the cylinder liner in the radial direction perpendicular to the axial direction of the cylinder liner, the coating occupies 50% or more of the area of the recesses formed between the protrusions of the cylinder liner.
3. The joint according to claim 1, wherein in a cross-section of the cylinder liner in the radial direction perpendicular to the axial direction of the cylinder liner, the recesses formed between the protrusions of the cylinder liner have the coating with a thickness of 0.2 mm or more.
4. The joint according to claim 1, wherein in a cross-section of the cylinder liner perpendicular to the axial direction of the cylinder liner, the cross-section having the coating exists in the recesses formed between the protrusions of the cylinder liner over the entire outer surface.
5. The joint according to claim 1, wherein in a cross-section of the cylinder liner radially perpendicular to the axial direction of the cylinder liner, the coating is present in the recesses formed between the protrusions of the cylinder liner, regardless of the cross-section in any axial direction of the cylinder liner.
6. The bonded body according to claim 1, wherein the resin material or rubber material is silicone rubber.
7. A cylinder liner cast into an aluminum alloy cylinder block, The cylinder liner has a plurality of protrusions extending from the central axis side to the outer circumference side, A cylinder liner having a coating made of a resin material or a rubber material in the recesses formed between the plurality of protrusions.
8. The aforementioned multiple protrusions are located 100 mm on the outer surface of the cylinder liner. ２ The cylinder liner according to claim 7, having 10 to 100 units per unit.
9. The cylinder liner according to claim 7, wherein the resin material or rubber material is silicone rubber.
10. The cylinder liner according to claim 7, wherein in a cross-section of the cylinder liner in the radial direction perpendicular to the axial direction of the cylinder liner, the recesses formed between the protrusions of the cylinder liner have the coating with a thickness of 0.2 mm or more.