JP2006256955A - Instrument having wear-resistant member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument having excellent durability, with which wear of a mate member made of a metal can be restrained and at the same time, wear of a wear-resistant member itself made of a ceramic sintered compact is restrained. <P>SOLUTION: The instrument has; a wear-resistant member which is made of at least one kind of ceramic sintered compact selected from the group comprising silicon nitride, zirconia, silicon carbide, cermet, sialon, aluminum nitride and alumina and used as a cam roller, a bearing ball, a check ball, a wear pad, a plunger or a roller; and a mate member made of a metal, which is provided so that at least one part thereof is brought into contact with the wear-resistant member. The wear-resistant member is characterized in that the skewness of the sliding contact surface between the mate member and itself is 0 to -2 and the ratio of the area occupied by pores to a depth of 500 μm from the sliding contact surface is not higher than 5% per unit area (1 mm<SP>2</SP>). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a device having a wear-resistant member, and particularly to a device having a wear-resistant member made of a ceramic sintered body and suitably used as a general work device.

  Conventionally, metal parts have been used for wear parts such as cam rollers, bearing balls, check balls, wear pads, and plungers used in industrial equipment and automobiles. However, when metal parts are used in the above-mentioned places, these parts may be worn violently due to friction, failing to exhibit a predetermined performance, or may be damaged in severe cases. In addition, these metal parts are heavy, so they are not suitable for weight reduction and high performance, and furthermore, heat resistance and corrosion resistance are low, so the service life is shortened in harsh environments and the economy is not excellent. . For this reason, high-performance parts that can replace metal parts have been desired.

  In order to solve these problems, ceramic sintered bodies have recently been used for wear-resistant parts. Since these ceramic sintered bodies are superior in wear resistance as compared with metal parts, they can maintain a predetermined performance for a long period of time, and are excellent in economy because they do not break. In addition, since it is lighter than metal parts, it is possible to increase the rotation speed and to achieve higher performance than before.

  However, it has been found that when such a ceramic sintered body is used in a device, the ceramic sintered body itself is not worn, but the parts in contact with the ceramic sintered body are worn away. This has become a problem in wear-resistant parts used in fuel injection devices such as automobiles, particularly cam rollers. This is because the hardness of the ceramic sintered body is high, but the hardness of the metal part in contact with the ceramic sintered body is low. In order to solve such a problem, it is conceivable that all parts are made of a ceramic sintered body. However, this is not done because it is not easy to process and economical.

  On the other hand, in the field of the electronics industry, a ceramic circuit board in which a metal plate such as a copper plate is bonded to a ceramic substrate is used in a substrate for mounting a semiconductor component handling high power. Ceramic sintered bodies are excellent in insulation, heat resistance, and thermal conductivity, and are preferably used for substrates and heat sinks.

  However, when a ceramic sintered body is used as a substrate, peeling and breakage may occur due to poor bondability with metal. For this reason, attempts have been made to improve the bondability with metal by controlling the composition and structure of the ceramic sintered body to prevent peeling and breakage, but such problems still occur.

  If a ceramic sintered body is used as a substitute for a metal part as a part of equipment, etc., the ceramic sintered part that is a high-hardness material attacks the metal part that is the counterpart part, and the metal part is In some cases, the amount of wear of the metal counterpart is increased compared to the case of using it. In particular, wear-resistant parts used in fuel injection devices such as automobiles have become an important problem.

  In the field of the electronics industry, a ceramic circuit board in which a metal plate such as a copper plate is bonded on a ceramic substrate is used for a substrate for mounting a semiconductor component handling high power. However, when a ceramic sintered body is used as a substrate, peeling and breakage may occur due to poor bondability with metal.

  In view of the above, the present invention is an apparatus having a wear-resistant member made of a ceramic sintered body and a metal counterpart component provided so that at least a part thereof is in contact with the wear-resistant member. An object of the present invention is to provide a device with higher durability, in which wear of the mating part is suppressed and wear of the wear-resistant member itself made of a ceramic sintered body is suppressed.

An apparatus having a wear-resistant member of the present invention comprises a ceramic sintered body made of at least one selected from silicon nitride, zirconia, silicon carbide, cermet, sialon, aluminum nitride, and alumina, and includes a cam roller and a bearing ball. A wear-resistant member used as a check ball, a wear pad, a plunger, or a roller, and a metal mating component provided so that at least a part of the wear-resistant member is in contact with the wear-resistant member. In the wear member, the skewness of the sliding contact surface with the metal counterpart is 0 to -2, and the area occupied by the pores to a depth of 500 μm from the sliding contact surface is 5% per unit area (1 mm ² ). It is characterized by not exceeding.

  In the apparatus having the wear-resistant member of the present invention, it is preferable that the skewness of the sliding contact surface of the wear-resistant member is 0 to −1. The average pore size in the wear-resistant member is preferably 30 μm or less.

According to the present invention, the cam roller, the bearing ball, the check ball, and the wear pad are made of a ceramic sintered body made of at least one selected from silicon nitride, zirconia, silicon carbide, cermet, sialon, aluminum nitride, and alumina. In a device having a wear-resistant member used as a plunger or a roller and a metal mating component provided so as to be at least partially in contact with the wear-resistant member, By setting the skewness of the sliding contact surface to 0 to -2 and preventing the area occupied by the pore from the sliding contact surface to a depth of 500 μm does not exceed 5% per unit area (1 mm ² ), the metal counterpart The wear of the parts is suppressed, and the wear of the wear-resistant member itself made of ceramic sintered body is also suppressed, making it more durable It is possible to provide an excellent device.

Hereinafter, modes for carrying out the present invention will be described.
An apparatus having a wear-resistant member of the present invention comprises a ceramic sintered body made of at least one selected from silicon nitride, zirconia, silicon carbide, cermet, sialon, aluminum nitride, and alumina, and includes a cam roller and a bearing ball. And a wear-resistant member used as a check ball, a wear pad, a plunger, or a roller, and a metal mating component provided so that at least a part thereof is in contact with the wear-resistant member. And in the apparatus which has a wear-resistant member of the present invention, the skewness of the sliding contact surface with the metal counterpart part in the wear-resistant member is set to 0-2, and the depth of 500 μm from this sliding contact surface. It is characterized in that the area occupied by the pores does not exceed 5% per unit area (1 mm ² ).

  The ceramic sintered body used in the present invention is a ceramic sintered body produced by forming and sintering a raw material, and the skewness of the contact surface in the ceramic sintered body is 0 or less. is there.

  Skewness (Sk) is a parameter of surface roughness and is also called distortion. The skewness is a value that represents the objectivity in the vertical magnification direction of the amplitude distribution curve and is given by the following equation.

  That is, as shown in FIG. 1A, the skewness is zero (0) when the surface roughness is substantially equal in the vertical direction. On the other hand, as shown in FIG. 1B, when the amplitude of the surface roughness is biased upward, the skewness is positive (> 0). Such a state indicates that the surface (tangent surface) has many convex portions. Then, as shown in FIG. 1C, when the convex portion with respect to the surface (tangent surface) is reduced and the amplitude of the surface roughness is biased downward, the skewness becomes negative (<0). .

  When such a ceramic sintered body is used as a structural member, for example, when the skewness of the contact surface is set to 0 or less, it is possible to reduce the wear of the mating member to be contacted. In particular, when the mating member is made of a metal material, the effect of reducing this wear is high. In addition, when used as a substrate in the electronics industry or the like, by setting the skewness to 0 or less, it is possible to increase a bonding force with a metal or the like and to produce a substrate that is less likely to be peeled off.

  As such a ceramic sintered body, it is preferable to use silicon nitride, zirconia, silicon carbide, cermet, sialon, aluminum nitride, alumina or the like. For example, when a structural member is manufactured using silicon nitride, zirconia, silicon carbide, cermet, or sialon as a material, a member having excellent heat resistance, durability, corrosion resistance, and the like can be manufactured at low cost. In addition, by manufacturing a substrate or the like using aluminum nitride, alumina, silicon nitride, or the like, a substrate having excellent thermal conductivity or the like can be manufactured at low cost.

In such a ceramic sintered body, the area occupied by the pores from the contact surface to a depth of 500 μm does not exceed 5% per unit area (1 mm ² ). When the area occupied by the pore from the contact surface to a depth of 500 μm exceeds 5% per unit area, the contact surface becomes rough and the mating member is easily worn. Further, when such a substrate is used as a substrate, since there are many pores, the bonding force with a metal or the like becomes weak, and damage due to peeling or the like is likely to occur.

  Therefore, when the skewness is set to 0 or less and the area occupied by the pore from the contact surface to a depth of 500 μm does not exceed 5% per unit area, for example, when used as a structural member, the wear of the mating member or the like When it is used for a substrate or the like, it is possible to further improve the bonding with a metal or the like, and to prevent damage due to peeling or the like.

  The area occupied by the pores from this contact surface to a depth of 500 μm is more preferably 1% or less. By doing so, it is possible to further increase the bonding strength with the metal circuit board. Moreover, it is preferable that the average pore size of such a ceramic sintered body is 30 μm or less. Wear can be further reduced by setting the average pore size to 30 μm or less.

  The wear-resistant member used in the present invention is manufactured using the ceramic sintered body as described above, and has a contact surface (sliding contact surface) with a skewness of 0 to −2. . In the wear-resistant member, the skewness of the slidable contact surface is set to 0 or less. When the skewness of the slidable contact surface is greater than 0, the distribution of the convex portion on the surface roughness increases, and the metal counterpart component that is the counterpart member This is because the aggression to the metal increases, and it is easy to wear the metal mating parts.

  In addition, the skewness of the sliding contact surface is set to −2 or more because when the skewness of the sliding contact surface is smaller than −2, the strength (abrasion resistance) of the wear resistant member itself is lowered. This is because the wear member is easily worn.

  Therefore, the wear-resistant member used in the present invention uses the ceramic sintered body as described above, and the skewness of the sliding contact surface is set to 0 to -2, thereby greatly reducing the wear of the metal counterpart. In addition, it is possible to suppress wear of the wear-resistant member itself, and a device using such a device can be a device having higher durability. More preferably, the skewness of the slidable contact surface of the wear-resistant member should be in the range of 0-1. By doing so, the wear of the metal counterpart and the wear-resistant member itself can be further reduced, and a device using such a device can be made more durable.

  Such a wear-resistant member is preferably produced using, for example, silicon nitride, silicon carbide, zirconia, cermet, sialon, alumina, or the like as a material. These materials are excellent in heat resistance, corrosion resistance, etc. By using these substances for the material of the wear-resistant member, the wear of the wear-resistant member itself is greatly reduced while reducing the wear of the metal counterpart parts. be able to. Among these, it is particularly preferable to produce a wear-resistant member using silicon nitride.

  The wear-resistant member is used as a cam roller, a bearing ball, a check ball, a wear pad, a plunger, or a roller. By using such a wear-resistant member as described above, a device using such a device can be made more durable, and the service life can be greatly prolonged. .

  The cam roller is used in, for example, a fuel injection device of a diesel engine, and is for taking a fuel injection timing. Since the cam roller is in contact with the inside of the cylindrical cam ring at high speed, the cam roller is worn when the cam roller is made of metal. In addition, when a conventional ceramic sintered body is used for the cam roller, the cam roller is not worn, but the cam ring is worn. For this reason, a deviation occurs in the fuel injection timing, and the predetermined performance cannot be exhibited. By producing the cam roller with the wear-resistant member as described above, it is possible to prevent performance degradation due to such wear.

  The bearing ball is spherical and supports the rotating shaft. Since the bearing ball is in contact with the rotating shaft at high speed and a high pressure is applied, the bearing ball is required to have strength and wear resistance, and further, it is also required not to wear the mating member. By using the wear-resistant member as described above for such a bearing ball, it is possible to solve these problems and produce a reliable and high-performance bearing ball.

  The check ball is spherical and is provided in a flow meter to measure the flow rate of gas or the like. This check ball is in contact with the inner wall surface of the flow meter and is constantly moved, so that it is easily worn, and the inner wall surface of the flow meter is also worn. Such wear reduces the accuracy of the flow meter and gives inaccurate values. Therefore, by producing the check ball using the wear-resistant member as described above, such wear can be prevented and the accuracy of the flow meter can be made constant.

  The wear pad is a part that slides with, for example, a rocker arm of an automobile engine. By using the wear-resistant member as described above for the wear pad, wear resistance is improved, stable combustion is achieved, Complete combustion can be reduced.

  The plunger is used in a fuel injection device of a diesel engine, etc., and transmits the movement of the cam roller, contacts the inside of the rotor, and reciprocates at high speed. Therefore, the plunger is very easily worn and the rotor is also worn. By using the wear-resistant member as described above for such a plunger, it is possible to prevent such wear and perform fuel injection accurately.

  The apparatus having the wear-resistant member of the present invention is an apparatus having the wear-resistant member used as a cam roller, a bearing ball, a check ball, a wear pad, a plunger, or a roller as described above. Specific examples include devices such as the above-described flowmeters, automobile engines, and fuel injection devices.

In the present invention, as a wear-resistant member used in contact with a metal counterpart component in such an apparatus, the skewness of the sliding contact surface is 0 to −2, and the pores are formed to a depth of 500 μm from the sliding contact surface. By using a device that occupies no more than 5% per unit area (1 mm ² ), the wear of the metal counterpart can be suppressed, and the wear of the wear-resistant member itself can be suppressed. It can be.

  Moreover, the ceramic sintered body demonstrated previously can be used as a member for electronic components, for example, can be used suitably as a board | substrate, a heat sink, etc. The substrate and the heat radiating plate are used by being bonded to a metal, but if the bonding force is weak, peeling or the like may occur and break. By using a ceramic sintered body as described above for such an electronic component member, it is possible to manufacture a reliable electronic component that enhances bonding with metal and does not cause peeling.

  Such a member for electronic parts such as a substrate and a heat sink is preferably made of at least one of aluminum nitride, silicon nitride, and alumina, for example. In recent years, circuits and the like have become complicated, and the amount of heat generated therewith tends to increase. Therefore, a substrate on which such a circuit or the like is loaded preferably has a good thermal conductivity and excellent heat dissipation. By using at least one of aluminum nitride, silicon nitride, and alumina as a component for electronic parts, there is no peeling of metal, etc., and high reliability and high performance with excellent heat dissipation. can do.

  The ceramic sintered body used in the present invention is produced, for example, as follows.

  For example, silicon nitride powder or the like is used as a raw material powder, and yttria or the like is added as a sintering aid to the raw material powder to prepare a predetermined composition. This is mixed in isopropyl alcohol or the like using silicon nitride balls for 24 hours, and then added with a binder and molded at a pressure of 1 ton using cold isostatic pressing (CIP) or the like. The obtained molded body is degreased at 500 ° C. for 4 hours and then fired at 1800 ° C. for 4 hours. As such a molding / firing method, a known method can be applied.

  Further, at least the surface that becomes the contact surface (sliding contact surface) is ground with a diamond grindstone and the contact surface (sliding contact surface) is barrel-polished or lapped to remove convex portions on the surface roughness. The skewness of the contact surface of the ceramic sintered body can be reduced to 0 or less.

Also, by removing the surface alteration layer on the surface by the above-mentioned grinding process, etc., ceramic sintering is produced so that the area occupied by pores from the contact surface to a depth of 500 μm does not exceed 5% per unit area (1 mm ² ). can do.

  The wear-resistant member used in the present invention can be produced by performing the above-described grinding before or after processing such a ceramic sintered body into a predetermined shape and setting the skewness to 0-2. Moreover, the member for electronic components can also be produced using the ceramic sintered body described above.

  Next, the present invention will be specifically described with reference to examples and reference examples.

Example 1
Using silicon nitride, yttria, and alumina as raw material powder, these are granulated and rubber press molded at a pressure of 1 ton / cm ² to form a cylindrical body of φ12.5 × 26 mm, and after degreasing, in a N ₂ atmosphere Was sintered at 1800 ° C. for 4 hours to obtain a Si ₃ N ₄ cylindrical sintered body having a density of 3.33 g / cc. This was diamond processed to produce a cam roller of φ9.525 ± 0.001 × 20.15 ± 0.001 mm.

  Furthermore, cam rollers A, B, C, and D having four different Sk values were manufactured by wet centrifugal barrel processing using alumina media. The cam roller A has a Sk value outside the range of the present invention, and is a comparative example for the embodiment of the present invention. In order to examine the wear amount of the ceramic sintered body having such different Sk values, it was mounted on a fuel injection pump for a diesel engine and the total wear amount was measured. The evaluation was conducted for 400 hours at RAIL PRESSURE 1000BAR and 2000ERPM. For comparison, a steel cam roller E was prepared and subjected to the same test. The test results are shown in Table 1.

As shown in Table 1, among A, B, and C where the value of Sk is 0 or less, the amount of wear was significantly reduced in B and C. A in which the value of Sk was significantly less than 0 resulted in an increase in the wear amount. When the Sk value was greater than 0, the wear amount was 5.5 mm ³ / N · mm, and the wear amount was higher than that of the conventional steel cam roller E.

(Example 2)
In order to study the allowable range of the allowable pore size distribution in the vicinity of the contact surface and in the vicinity of the contact surface that affects the rolling life characteristics of the roller, six types of rollers as shown in Table 2 were prepared, and these injection pump rollers The applicability was evaluated.

  As the roller, a cylindrical body having a diameter of 12.5 × 26.0 mm was formed by uniaxially pressing the powder. The skewness of the contact surface was set to −1, and the area occupied by the pores was set to the values shown in Table 2 by changing the pressure of uniaxial pressing.

  Using the six types of rollers thus obtained, the durability test was performed by changing ERPM and RAIL PRESSURE. The results of the durability test are shown in FIG.

  C, D, and E having the same average pore size resulted in the lowest pore occupation area and the highest durability of C. In D and E, the durability of D having a low occupation area was higher than that of E with some exceptions.

  In B, D, and F, in which the occupied area of the pore is equal to 0.8%, the durability of B having the smallest average pore size was the highest, followed by D and F in that order. F having a large average pore size did not have a predetermined durability and was damaged.

  Even when the area occupied by the pores was 1%, A having a small average pore size resulted in very high durability.

(Example 3)
Using the members A and C used in Example 2, the amount of wear when the skewness value was changed as shown in Table 3 was measured. The measurement conditions for the amount of wear were the same as in Example 2.

  As shown in Table 3, it was found that even if the average pore size and the pore occupation area are the same, the difference in skewness makes a great difference in the amount of wear.

(Reference example)
In order to investigate the influence of the skewness of the substrate contact surface on the bonding force, a copper plate was bonded to an AlN substrate having a different skewness using the direct bonding method (DBC method), and the peel strength was measured. As shown in Table 4, AlN substrates having a skewness of 0, -1, or +0.5 were used as Reference Examples 1 to 3, respectively. The AlN substrate is 50 mm long × 25 mm wide × 0.8 mm thick, and the copper plate is 0.25 mm thick tough pitch copper and held in a heating furnace set at a temperature of 1075 ° C. for 1 minute. And joined.

  As shown in Table 4, it can be seen that Reference Examples 1 and 2 in which the skewness is 0 or −1 have higher bonding strength with the copper plate than Reference Example 3 in which the skewness is +0.5. In particular, when the skewness is set to -1, the bonding strength is significantly improved.

It is a figure for demonstrating skewness. It is a figure which shows the result of the durability test of an abrasion-resistant member.

Claims (3)

Consists of a ceramic sintered body consisting of at least one selected from silicon nitride, zirconia, silicon carbide, cermet, sialon, aluminum nitride and alumina, as cam roller, bearing ball, check ball, wear pad, plunger or roller A device having a wear-resistant member used and a metal mating component provided so that at least a part thereof is in contact with the wear-resistant member,
In the wear-resistant member, the skewness of the sliding contact surface with the metal counterpart is 0 to -2, and the area occupied by the pore from the sliding contact surface to a depth of 500 μm is a unit area (1 mm ² ). Equipment with wear-resistant members characterized by not exceeding 5% per hit.   The apparatus having a wear-resistant member according to claim 1, wherein the skewness of the sliding contact surface of the wear-resistant member is 0 to -1.   The device having an abrasion-resistant member according to claim 1 or 2, wherein an average pore size in the abrasion-resistant member is 30 µm or less.

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