JP2007002989A - Slide member, cylinder using the slide member, and internal combustion engine using the cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slide member which has excellent abrasion resistance and anti-seizing property, and can maximize the reducing effect of the frictional coefficient in the slide surface. <P>SOLUTION: A cylinder 10 can slide relatively to a piston 20 via lubricating agent. A plurality of recesses 12 are formed in the sliding surface of the piston 20. At least either one of the shape of the opening of the recesses 12, the dimension of the opening of the recess 12, the depth of the recesses 12, the sectional form of the recess 12, the total volume of the recesses 12 formed for unit area of the inside 11 of the cylinder 10, and the total area of the opening of the recesses 12 formed for unit area of the inside surface 11 differs according to the position of the sliding direction P and/or the direction perpendicular to the sliding direction P. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sliding member, a cylinder to which the sliding member is applied, and an internal combustion engine to which the cylinder is applied. In particular, the present invention relates to a sliding member used in an automobile, a cylinder to which the sliding member is applied, and an internal combustion engine to which the cylinder is applied.

Environmental issues such as global warming is significantly close up on a global scale, the development of automobile fuel efficiency improvement technologies for CO ₂ reduction in the atmosphere has become a major issue, as part of this, sliding to be used in the engine Reduction of the friction loss of a member is calculated | required. In view of this, in recent years, the development of sliding member materials, surface treatment, and modification technologies that are excellent in wear resistance and seizure resistance and that can maximize the effect of reducing the friction coefficient have been developed. It is being advanced. As one of such techniques, a technique for forming a plurality of recesses on a sliding surface of a sliding member has been developed (Patent Document 1). This recess is provided for the purpose of holding the lubricant when the sliding member slides.
JP 2002-235852 A

  However, the friction characteristics on the sliding surface, such as the frictional force generated on the sliding surface and the degree of wear, differ depending on the sliding direction of the sliding member and / or the position in the direction orthogonal to the sliding direction. If the concave portion is formed on the sliding surface without considering the difference in friction characteristics, a sufficient friction reducing effect may not be exhibited.

  The present invention has been made in view of the above-described problems of the prior art, and provides a sliding member that is excellent in wear and seizure resistance and that can maximize the effect of reducing the friction coefficient on the sliding surface. This is the issue.

  The object of the present invention is achieved by the following means.

  (1) A sliding member that can slide relative to another member with a lubricant interposed therebetween, wherein a plurality of recesses are formed on a sliding surface with the other member, and an opening of the recess The shape of the recess, the dimension of the opening of the recess, the depth of the recess, the cross-sectional shape of the recess, the total volume of the recess formed per unit area of the sliding surface, and the unit area of the sliding surface At least any one of the total area of the opening part of a recessed part differs according to the position of the direction orthogonal to a sliding direction and / or a sliding direction of the said sliding member, The sliding member characterized by the above-mentioned.

  (2) The sliding surface has at least a first region and a second region to which a larger load than the first region can be applied, and is formed per unit area in the first region. (1) The sliding member according to (1), wherein the total volume of the recesses is larger than the total volume of the recesses formed per unit area in the second region.

  (3) The sliding surface has at least a first region and a second region to which a larger load than the first region can be applied, and a depth of a recess formed in the first region. Is deeper than the depth of the recess formed in the second region. The sliding member according to (1),

  (4) The sliding surface has at least a first region and a second region to which a larger load than the first region can be applied, and is formed per unit area in the first region. (1) The sliding member according to (1), wherein the total area of the openings of the recesses is larger than the total area of the openings of the recesses formed per unit area in the second region.

  (5) A cylinder to which the sliding member according to any one of (2) to (4) is applied and which can slide relatively with a piston provided with a piston skirt and a lubricant interposed therebetween. A plurality of recesses are formed on the inner surface of the cylinder, which is a sliding surface with the piston, and the second region is a region of the inner surface where the piston skirt and the cylinder are in sliding contact with each other. The region is a region other than the second region in the inner surface.

  (6) The ratio of the total area of the openings of the plurality of recesses formed on the inner surface with respect to the area of the inner surface is 0.5% or more and 10% or less, and the depth of the recess is 0.5 μm or more. The cylinder according to (5), which is 20 μm or less.

  (7) The cylinder according to (5) or (6), wherein the member forming the inner surface is made of an aluminum alloy.

  (8) The cylinder according to any one of (5) to (7), wherein the Si content of the member forming the inner surface is 12% or less.

  (9) An internal combustion engine including the cylinder according to any one of (5) to (8) and the piston, wherein the piston further includes a piston ring that can be in sliding contact with an inner surface of the cylinder. An internal combustion engine characterized in that an amorphous hard carbon film is formed on one or both of the piston ring and the piston skirt.

  According to the present invention, in a sliding member that can slide relative to another member with a lubricant interposed therebetween, when forming a plurality of concave portions on the sliding surface with the other member, the opening portion of the concave portion The recess formation conditions such as the shape of the recess and the size of the opening of the recess are made different according to the sliding direction of the sliding member and / or the position in the direction orthogonal to the sliding direction.

  Thereby, the sliding member of this invention is excellent in abrasion resistance and seizure resistance, and can exhibit the reduction effect of the friction coefficient in a sliding surface to the maximum.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an engine block 1 in the present embodiment.

  As shown in FIG. 1, the engine block 1 in this embodiment includes a cylinder 10 having a cylindrical shape and a piston 20 that can be inserted into the cylinder 10.

  The piston 20 is connected to a connecting rod 22 that is rotatably provided via a piston pin 21 and is provided so as to reciprocate in a direction P (hereinafter referred to as a sliding direction P). During the reciprocating motion, the piston 20 is pressed against the thrust / anti-thrust area (second area or less, thrust / anti-thrust area) S, AS on the inner surface 11 of the cylinder 10 by the rotation of the connecting rod 22. Slide while. In addition, the engine block 1 in this embodiment is a type which does not use a cylinder liner, and the inner surface 11 of the cylinder 10 and the piston 20 are in direct contact.

  Further, the piston 20 has a piston skirt 23 disposed in a direction perpendicular to the axis of the piston pin 21 with respect to the piston pin 21, and a piston ring 24 provided so as to protrude from the surface of the piston 20. The piston ring 24 is attached to the piston 20 with a predetermined tension applied, and the outer peripheral surface of the piston ring 24 is in sliding contact with the inner surface 11 of the cylinder 10 with uniform pressure over the entire periphery.

  FIG. 2 is a schematic diagram for explaining a state in which the inner surface 11 of the cylinder 10 is divided according to the magnitude of the load applied to the inner surface 11.

  As described above, the piston 20 slides so as to be pressed against the thrust direction / anti-thrust direction regions S and AS by the rotation of the connecting rod 22. Thereby, the magnitude | size of the load added to the inner surface 11 is not uniform over the whole inner surface 11 of the cylinder 10, and differs according to the position on the inner surface 11. FIG. That is, the load applied from the piston 20 in the thrust direction / anti-thrust direction region S, AS is in the region Y in the direction Y orthogonal to the thrust / anti-thrust direction X (the first region or less, the orthogonal direction region) R, R. It is larger than the load applied from the piston 20. Further, as described above, the piston skirt 23 is in a direction perpendicular to the axis of the piston pin 21 with respect to the piston pin 21 (that is, the direction in which the piston 20 is pressed against the inner surface 11 of the cylinder 10 by the rotation of the connecting rod 22). ), When the piston 20 slides, the piston skirt 23 comes into sliding contact with the thrust direction / anti-thrust direction regions S and AS.

  In the present embodiment, in order to maximize the effect of reducing the coefficient of friction on the sliding surface between the cylinder 10 and the piston 20, considering the difference in load applied to the inner surface 11, the plurality of recesses 12 are The inner surface 11 is formed so as to satisfy the following formation conditions.

  FIG. 3 is a development view showing the inner surface 11 of the cylinder 10.

  The shape of the opening of the recess 12, the size of the opening of the recess 12, the depth of the recess 12, the cross-sectional shape of the recess 12, the total volume of the recess 12 formed per unit area of the inner surface 11 of the cylinder 10, and the inner surface 11 At least one of the total areas of the openings of the recesses 12 formed per unit area is at a position in the sliding direction P (vertical direction shown in FIG. 3) and / or a direction perpendicular to the sliding direction P. Depending on it.

The total volume of the recesses 12 formed per unit area of the orthogonal direction regions R and R is the total volume of the recesses 12 formed per unit area of the thrust direction / anti-thrust direction regions S and AS (mm ³ / mm ² ).

  Further, the depth of the concave portion 12 formed in the orthogonal direction regions R and R is larger than the depth of the concave portion 12 formed in the thrust direction / anti-thrust direction regions S and AS.

  The total area of the openings of the recesses 12 formed per unit area of the orthogonal direction regions R and R is the sum of the openings of the recesses 12 formed per unit area of the thrust direction / anti-thrust direction regions S and AS. Greater than total area. In addition, regarding the conditions regarding the depth of the concave portion 12 and the total area of the openings of the concave portion 12 described above, the concave portion 12 may be formed so as to satisfy only one of the conditions, or to satisfy both conditions. May be formed.

  The ratio of the total area of the openings of the plurality of recesses 12 formed in the inner surface 11 with respect to the area of the inner surface 11 (hereinafter referred to as area ratio) is 0.5% or more and 10% or less. The depth of 12 is preferably 0.5 μm or more and 20 μm or less. This is because, when the area ratio of the recess 12 is less than 0.5%, or when the depth of the recess 12 is less than 0.5 μm, the volume of the recess 12 is small and the lubricating oil cannot be sufficiently retained, Further, when the area ratio of the recess 12 is larger than 10% or the depth of the recess 12 is larger than 20 μm, the friction loss between the inner surface 11 of the cylinder 10 and the piston 20 is increased. It is.

  By forming the recess 12 that satisfies the above-described formation conditions on the inner surface 11 of the cylinder 10, it is excellent in wear resistance and seizure resistance, and the effect of reducing the friction coefficient on the sliding surface can be maximized.

  Further, by forming the concave portion 12 on the inner surface 11 of the cylinder 10, the effects such as the effect of reducing the friction coefficient on the sliding surface described above are exhibited. Therefore, the member that forms the inner surface 11 is an ADC (aluminum alloy). The Si content of the member can be made 12% or less. That is, without using a material such as ADC14 in which Cu or Mg is added to an Al—Si hypereutectoid alloy developed for the purpose of reducing the weight of the engine block and the matrix is reinforced, for example, the Si content is 10%. An aluminum alloy such as about 8% Al—Si—Cu based ADC12 can be used. Thereby, the conventional cast iron cylinder liner becomes unnecessary, and the number of parts can be reduced and the manufacturing process can be simplified.

  Moreover, it is preferable that an amorphous hard carbon film is formed on one or both of the piston skirt 23 and the piston ring 24. Thereby, wear resistance and seizure resistance are ensured, and the effect of reducing the friction coefficient on the sliding surface lasts for a long period of time.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, the sliding member having the concave portion formed on the surface is not limited to the above-described cylinder, and examples thereof include a cylinder liner, a piston, and a piston ring.

<Example>
Next, it is intended to verify that the sliding member shown in the above embodiment is excellent in wear resistance and seizure resistance, and exhibits the effect of maximizing the effect of reducing the friction coefficient on the sliding surface. As a result, a test specimen was actually prepared and the friction force generated on the sliding surface was measured. As test specimens, the test specimens of Examples 1 to 3 in which recesses were formed according to the formation conditions described in the above embodiment and the test specimens of Comparative Examples 1 and 2 for comparison with Examples 1 to 3 were manufactured. .

  First, the characteristics of the test body of Example 1 will be described.

  The test body of Example 1 was manufactured using ADC12 material used as a material of the cylinder of an engine block. Specifically, using a QR25 engine (4-cylinder 2500CC, bore diameter φ89) manufactured by Nissan Motor Co., Ltd., the cast iron liner was scraped off, and an ADC 12 die-cast AL liner as a test specimen was pressed into the bottom. The test body has a hollow cylindrical shape, and a recess is formed on the inner surface. The recess was formed using a mask blasting process. The mask blasting process is a process that uses optical lithography technology. Specifically, after applying a resin mask having a concave shape on the inner surface of a test specimen, alumina abrasive grains having an average particle diameter of 20 μm are projected. This is a process of projecting from a nozzle onto a workpiece to form a recess on the inner surface of the test body. As projection conditions, the distance from the projection nozzle to the workpiece was set to 100 mm, the projection flow rate was set to 100 g / min, and the projection pressure was set to 0.4 MPa. Further, after the projection, the bulge of the edge portion formed around the recess 12 was removed using a tape wrap film having a particle size of 9 μm to obtain a test body of Example 1.

  FIG. 4 is an enlarged view showing an arrangement pattern of the recesses 12 formed on the inner surface of the test body in this example.

  As described above, a plurality of concave portions 12 having a constant depth arranged in a staggered pattern as shown in FIG. 4 were formed on the inner surface of the test body of Example 1. The staggered arrangement pattern is an arrangement pattern in which equilateral triangles are formed when the center points of the openings of the three adjacent recesses 12 are connected. By adjusting the size of the equilateral triangle, the per unit area It adjusted so that the area (area ratio) of the recessed part 12 might become a desired value. In addition, the dimension (height H x width W) of the opening part of each recessed part 12 is 80 micrometers x 320 micrometers.

  Moreover, in the test body of Example 1, the area ratio of the recess 12 in the thrust direction / anti-thrust direction regions S and AS is 5.0%, the depth of the recess 12 is 3.0 μm, and the recesses in the orthogonal direction regions R and R. The area ratio of 12 is 10%, and the depth of the recess 12 is 6.0 μm. That is, the area ratio and depth of the recess 12 in the test body of Example 1 are included in the range described in the above-described embodiment.

  Next, the characteristics of the test body of Example 2 will be described.

  The test body of Example 2 is the same as the test body of Example 1, the area ratio of the recesses 12 formed in each of the thrust direction / anti-thrust direction regions S and AS and the orthogonal direction regions R and R, and the depth of the recesses 12. Different in. Specifically, in the specimen of Example 2, the area ratio of the recess 12 in the thrust direction / anti-thrust direction region S, AS is 2.5%, the depth of the recess 12 is 3.0 μm, the orthogonal region R, The area ratio of the recess 12 in R is 5.0%, and the depth of the recess 12 is 3.0 μm. That is, the area ratio and depth of the recess 12 in the test body of Example 2 are included in the range described in the above-described embodiment. Since the other conditions are the same as those of the specimen of Example 1, the description thereof is omitted.

  Next, the characteristics of the test body of Example 3 will be described.

  The test body of Example 3 is the same as the test body of Examples 1 and 2, and the area ratio of the recess 12 formed in each of the thrust direction / anti-thrust direction regions S and AS and the orthogonal direction regions R and R, Different in depth. Specifically, in the specimen of Example 3, the area ratio of the recess 12 in the thrust / anti-thrust region S, AS is 1.0%, the depth of the recess 12 is 3.0 μm, the orthogonal region R, The area ratio of the recess 12 in R is 5.0%, and the depth of the recess 12 is 3.0 μm. That is, the area ratio and depth of the recess 12 in the test body of Example 3 are included in the range described in the above-described embodiment. Since the other conditions are the same as those of the test body of Example 1, the description thereof is omitted.

  Next, the characteristics of the specimen of Comparative Example 1 will be described.

  The test body of Comparative Example 1 differs from the test bodies of Examples 1 to 3 in terms of the area ratio and depth of the recesses in each region of the inner surface. Specifically, in the specimen of Comparative Example 1, the area ratio of the recesses was 0.4% and the depth of the recesses was 0.4 μm in any of the thrust direction / anti-thrust direction region and the orthogonal direction region. is there. That is, the area ratio and depth of the recesses in the test body of Comparative Example 1 are not included in the range described in the above-described embodiment. Since the other conditions are the same as those of the test body of Example 1, the description thereof is omitted.

  Next, the characteristics of the test body of Comparative Example 2 will be described.

  The test body of Comparative Example 2 differs from the test bodies of Examples 1 to 3 and Comparative Example 1 in the conditions of the area ratio and depth of the recesses in each region of the inner surface. Specifically, in the specimen of Comparative Example 2, the area ratio of the recesses is 12% and the depth of the recesses is 20 μm in any of the thrust direction / anti-thrust direction region and the orthogonal direction region. That is, the area ratio and depth of the recesses in the test body of Comparative Example 2 are not included in the range described in the above-described embodiment. Since the other conditions are the same as those of the specimen of Example 1, the description thereof is omitted.

  In addition, about the formation conditions of the recessed part in the test body of Examples 1-3 and Comparative Examples 1-2 demonstrated so far, it put together in Table 1 shown later.

  FIG. 5 is a schematic view showing a main part of the piston-cylinder friction measuring machine 2.

  In order to evaluate the performance such as seizure resistance of each specimen in the above examples and comparative examples, a piston-cylinder friction measuring machine (QR25 engine (4-cylinder 2500CC, bore manufactured by Nissan Motor Co., Ltd.) shown in FIG. Using the diameter φ89)) 2, the friction force generated on the sliding surface of each specimen was measured by the motoring method. The friction measuring device 2 includes a piston 20 disposed in a fixed state and a support member 25 that can reciprocate in the direction Q. The piston 20 is provided with a piston ring 24 (top ring, second ring, and oil ring), and an amorphous hard carbon film is formed on the surface of the piston ring 24 by ion plating. When measuring the friction force generated on the sliding surface of the test body C using the friction measuring device 2, the test body C is mounted on the support member 25, and is fixed to the sliding surface between the fixed piston 20 and the test body C. While supplying the lubricating oil, the support member 25 was reciprocated in the Q direction, and the friction force generated on the sliding surface of the specimen C was measured.

  Next, measurement conditions will be described. The lubricating oil was engine oil 5W30, the oil temperature was 80 ° C., the amount of oil supplied was 100 cc / min, the sliding speed was 700 cpm, the reciprocating sliding distance was 70 mm, and 490 N was applied to the piston 20 as a thrust load.

  FIG. 6 is a graph showing the measurement results of the friction force in this example.

  As a result of the above measurement, the measurement result shown in FIG. 6 was obtained, and the friction work (area obtained by integration) obtained by integrating the curve shown in FIG. 6 was calculated. Then, the friction force and friction work in each example and comparative example were compared, and the wear resistance and seizure resistance of each example were examined. The results are shown in Table 1.

  The ratio of the friction force in Examples 1 to 3 is smaller than the ratio of the friction force in Comparative Examples 1 and 2. That is, it can be said that the friction coefficient on the sliding surface of the test bodies of Examples 1 to 3 is smaller than the friction coefficient on the sliding surface of the test bodies of Comparative Examples 1 and 2.

Accordingly, the total volume of the recesses 12 formed per unit area of the orthogonal direction regions R and R is changed to the total volume (mm ^{3) of the} recesses 12 formed per unit area of the thrust direction / anti-thrust direction regions S and AS. / Mm ² ) is understood to be effective for improving the wear resistance and seizure resistance and for exerting the effect of reducing the friction coefficient on the sliding surface.

  In addition, the depth of the concave portion 12 formed in the orthogonal direction regions R and R can be made larger than the depth of the concave portion 12 formed in the thrust direction / anti-thrust direction regions S and AS. It is understood that it is particularly effective.

  Further, the total area of the openings of the recesses 12 formed per unit area of the orthogonal direction regions R and R is the sum of the openings of the recesses 12 formed per unit area of the thrust direction / anti-thrust direction regions S and AS. It can be seen that increasing the total area is also effective in exerting the above effects.

  The ratio of the total area of the openings of the plurality of recesses 12 formed in the inner surface 11 to the area of the inner surface 11 (hereinafter referred to as area ratio) is 0.5% or more and 10% or less. It can be seen that setting the depth to 0.5 μm or more and 20 μm or less is also effective in exerting the above-described effects.

It is sectional drawing which shows the engine block in this embodiment. It is a schematic diagram for demonstrating the state which divided the inner surface of the cylinder with the magnitude | size of the load added to an inner surface. It is an expanded view which shows the inner surface of a cylinder. It is an enlarged view which shows the arrangement pattern of the recessed part formed in the inner surface of a test body in a present Example. It is the schematic which shows the principal part of a piston-cylinder friction measuring machine. It is a graph which shows the measurement result of the friction force in a present Example.

Explanation of symbols

10 cylinders,
11 Inside,
12 recess,
20 pistons,
23 piston skirt,
24 piston ring,
P sliding direction,
R, R Thrust / anti-thrust direction X-direction area Y (first area),
S, AS Thrust / anti-thrust region (second region).

Claims (9)

A sliding member that can slide relative to other members via a lubricant,
A plurality of recesses are formed on the sliding surface with the other member,
The shape of the opening of the recess, the size of the opening of the recess, the depth of the recess, the cross-sectional shape of the recess, the total volume of the recess formed per unit area of the sliding surface, and the unit area of the sliding surface At least one of the total areas of the openings of the recesses formed in the sliding member differs depending on the sliding direction of the sliding member and / or the position in the direction orthogonal to the sliding direction. Moving member. The sliding surface has at least a first region and a second region to which a larger load than the first region can be applied,
The total volume of recesses formed per unit area in the first region is larger than the total volume of recesses formed per unit area in the second region. The sliding member. The sliding surface has at least a first region and a second region to which a larger load than the first region can be applied,
2. The sliding member according to claim 1, wherein the depth of the recess formed in the first region is deeper than the depth of the recess formed in the second region. The sliding surface has at least a first region and a second region to which a larger load than the first region can be applied,
The total area of the recess openings formed per unit area in the first region is larger than the total area of the recess openings formed per unit area in the second area. The sliding member according to claim 1. A sliding member according to any one of claims 2 to 4, wherein the sliding member is a cylinder that can slide relative to a piston provided with a piston skirt and a lubricant,
A plurality of recesses are formed on the inner surface of the cylinder, which is a sliding surface with the piston,
The second region is a region of the inner surface where the piston skirt and the cylinder are in sliding contact with each other,
The first area is a cylinder other than the second area in the inner surface. The ratio of the total area of the openings of the plurality of recesses formed on the inner surface with respect to the area of the inner surface is 0.5% or more and 10% or less,
The cylinder according to claim 5, wherein the depth of the recess is not less than 0.5 μm and not more than 20 μm.   7. The cylinder according to claim 5, wherein the member forming the inner surface is made of an aluminum alloy.   The cylinder according to any one of claims 5 to 7, wherein the Si content of the member forming the inner surface is 12% or less. An internal combustion engine comprising the cylinder according to any one of claims 5 to 8 and the piston,
The piston further includes a piston ring that can be in sliding contact with the inner surface of the cylinder,
An internal combustion engine, wherein an amorphous hard carbon film is formed on one or both of the piston ring and the piston skirt.

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