JP2008014454A - Sliding bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding bearing with a resin overlaid layer for effectively preventing the occurrence of crack or breakage in the resin overlaid layer due to foreign matter pushed thereagainst. <P>SOLUTION: In the inner periphery of the sliding bearing 1, a recessed portion 5 is formed extending to the peripheral direction and having a depth in a range from a sliding surface 4a of the resin overlaid layer 4 to a bearing alloy layer 3. The hardness of the bearing alloy layer 3 exposed into the recessed portion 5 is 50 HV or less. When foreign matter enters between another shaft and the sliding bearing 1, the foreign matter is easily entrapped in the recessed portion 5 and the foreign matter entrapped in the recessed portion 5 is embedded in the bearing alloy layer 3 or adhered onto the bearing alloy layer 3. This constitution prevents the rolling movement of the foreign matter on the sliding surface 4a of the resin overlaid layer 4 or in the recessed portion 5 for an long time to minimize the occurrence of crack or separation in the resin overlaid layer 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a slide bearing in which a resin overlay layer containing a solid lubricant is provided on a bearing alloy layer.

  A plain bearing for an internal combustion engine generally uses a Cu-based or Al-based alloy as a bearing alloy layer, and an overlay layer made of a soft metal such as a Pb-based alloy or a resin containing a solid lubricant is provided on the surface of the bearing alloy layer. Thus, the sliding characteristics are improved.

  Recently, from the viewpoint of reducing the amount of environmental pollutants used, there is a tendency to avoid the use of metals such as Pb-based alloys in the overlay layer. Under such circumstances, the overlay layer made of the above resin contains a solid lubricant and exhibits excellent lubricity and conformability, so it has good wear resistance and non-seizure properties, and is a high-power engine. It is increasingly used as a sliding bearing. In the following description, an overlay layer mainly composed of a resin is referred to as a resin overlay layer, and is distinguished from a metal overlay layer mainly composed of a metal such as a Pb-based alloy.

For example, in Patent Document 1, a resin overlay layer made of MoS ₂ as a solid lubricant and polyamideimide as a binder resin is formed on the surface of a bearing alloy layer made of a Cu-based alloy or an Al-based alloy. It is disclosed that a spiral groove for holding lubricating oil is formed on the surface (sliding surface) of the resin overlay layer. The groove on the sliding surface of the resin overlay layer may have a depth that stops within the resin overlay layer or a depth that extends to the bearing alloy layer.
JP-A-2004-211859 (see FIG. 5)

  Generally, a thermosetting resin such as a polyimide resin, an epoxy resin, or a phenol resin is employed as the resin used for the resin overlay layer (functioning as a binder for the solid lubricant). A resin overlay layer using such a thermosetting resin is thin and hardly plastically deformed as compared with a metal overlay layer, so that it cannot be said that the foreign substance burying property is sufficient. In addition, if foreign matter enters between the mating shaft and the foreign matter is pressed against the resin overlay layer, the plastic overlay layer has low plastic deformability, so that the sliding surface easily cracks, and the crack is the cause of peeling. This can lead to seizure.

  As shown in Patent Document 1, when a groove is formed in the resin overlay layer, the foreign matter can easily flow into the groove together with the lubricating oil, so that the foreign matter can be taken into the groove. However, foreign matter taken into the groove is pressed against the resin overlay layer on the inner surface of the groove by the mating shaft, or rolls in the groove with the rotation of the mating shaft, so that the resin overlay layer is not cracked or peeled off. It tends to occur.

  Even if the groove extends to the bearing alloy layer and the bearing alloy layer is exposed in the groove, a normal bearing alloy has a hardness higher than 50 HV, so that foreign matter taken into the groove may be pressed against the bearing alloy layer. It is not embedded in the bearing alloy layer, and foreign matter rolls in the groove as the mating shaft rotates, and damages the resin overlay layer to cause cracks and peeling.

  The present invention has been made in view of the above circumstances, and its purpose is to prevent foreign matter taken in the concave portion from rolling for a long time in the concave portion in the slide bearing in which the concave portion is formed in the resin overlay layer. Then, it is providing the slide bearing which can prevent effectively that a crack, peeling, etc. arise in a resin overlay layer.

  In order to achieve the above object, the present invention provides a cylindrical or halved shape, a bearing alloy layer on the inner periphery, and a resin overlay layer including a solid lubricant provided on the bearing alloy layer, The bearing alloy layer has a hardness of 50 HV or less, extends in the circumferential direction on the inner periphery, and extends from the sliding surface of the resin overlay layer to at least the surface of the bearing alloy layer. A concave portion having a thickness is formed, and the bearing alloy layer is exposed in the concave portion.

According to this configuration, since the concave portion extends in the circumferential direction, which is the sliding direction, foreign matter that has entered between the opposite shaft is easily taken into the concave portion.
In addition, in the present invention, the bearing alloy layer is exposed in the concave portion, and the bearing alloy layer exposed in the concave portion is relatively soft with a hardness of 50 HV or less, so foreign matter taken into the concave portion is contained in the bearing alloy layer. Embedded or adhered to the bearing alloy layer. For this reason, it can prevent that a foreign material rolls and moves within a recessed part, and it can prevent that a crack generate | occur | produces in a resin overlay layer or peeling arises as much as possible.

  The depth of the concave portion may be such that the bearing alloy layer is exposed in the concave portion. Therefore, the depth of the concave portion may be equal to the thickness of the resin overlay layer or deeper than the thickness of the resin overlay layer. When the depth of the concave portion is equal to the thickness of the resin overlay layer, the concave portion preferably has a rectangular cross-sectional shape so that the bearing alloy layer is exposed on the bottom surface of the concave portion.

The thickness of the resin overlay layer is 2 to 30 μm, preferably 10 to 25 μm.
The depth of the concave portion is not less than the thickness of the resin overlay layer and not more than 100 μm, and when many concave portions are formed, the pitch is preferably 200 to 300 μm.

The bearing alloy layer may be made of any one of a Cu alloy and an Al alloy. Examples of Cu-based alloys and Al-based alloys having a hardness of 50 HV or less include Al-Sn alloys.
As the solid lubricant for the resin overlay layer, molybdenum disulfide (MoS ₂ ), graphite (Gr), polytetrafluoroethylene (PTFE), tungsten disulfide (WS ₂ ), boron nitride (BN), or the like can be used. .

  As the resin (binder) constituting the resin overlay layer, a thermosetting resin such as a polyamideimide resin (PAI), an epoxy resin or a phenol resin, or a heat resistant resin such as a polybenzimidazole resin (PBI) is used. be able to.

Hard particles or soft metals may be added to the resin overlay layer. Examples of the hard particles include nitrides such as silicon nitride (Si ₃ N ₄ ), oxides such as aluminum oxide (Al ₂ O ₃ ) and silicon oxide (SiO ₂ ), and carbide particles such as silicon carbide (SiC). Can be used. As the soft metal, Cu, Ag, Al, Sn, Zn, alloys thereof and the like can be used.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 shows a plain bearing 1 used for an internal combustion engine, for example. This plain bearing 1 is a semi-cylindrical shape (half-divided shape), and two are used in a cylindrical shape. The plain bearing 1 includes a backing metal layer 2, a bearing alloy layer 3 deposited on the inner peripheral surface of the backing metal layer 2, and a resin overlay layer 4 deposited on the surface of the bearing alloy layer 3. It has a three-layer structure.

The bearing alloy layer 3 is made of a Cu-based or Al-based bearing alloy and has a hardness of 50 HV or less. The resin overlay layer 4 is made of a resin film such as PAI or PBI containing a solid lubricant such as MoS ₂ .

  A plurality of concave portions 5 extending in the circumferential direction are formed on the inner peripheral surface of the slide bearing 1 along the axial direction 8. As shown in FIG. 1, the concave portion 5 has, for example, a V-shaped cross section, and has a depth extending from the sliding surface 4 a of the resin overlay layer 4 to the bearing alloy layer 3. The bearing alloy layer 3 is exposed at the bottom.

  The manufacturing method of such a sliding bearing 1 will be described with reference to FIG. 3. First, as shown in FIG. 3A, a Cu-based or Al-based bearing alloy (bearing alloy layer 3) is formed on a steel plate (back metal layer 2). Is deposited by a known sintering method or pressure welding method to form a bimetal 6 and the bimetal 6 is bent into a semi-cylindrical shape as shown in FIG. Next, the surface of the bearing alloy layer 3 is roughened by shot blasting or the like, pickled to remove impurities adhering to the surface, and the surface of the bearing alloy layer 3 is activated.

Thereafter, a binder resin such as PAI or PBI diluted with a suitable organic solvent is mixed with a solid lubricant such as MoS ₂ , and this mixture is further diluted with an organic solvent such as N-methyl-2-pyrrolidone. Is applied to the surface of the bearing alloy layer 3 by air spray or the like to form a resin film. And it heats at 80-120 degreeC, for example, 100 degreeC for 30 minutes, and the organic solvent in a resin film is evaporated and dried. After drying, the resin film is pressed with a press or the like to be densified. Next, baking is performed at 150 to 400 ° C., for example, 200 ° C. for 60 minutes. As a result, the resin film is cured and formed as a resin overlay layer 4 shown in FIG. Thereafter, the inner peripheral surface is cut, and a concave portion 5 extending in the circumferential direction and having a depth extending from the sliding surface 4a of the resin overlay layer 4 to the bearing alloy layer 3 as shown in FIG. A plurality of lines are formed.

  According to the slide bearing 1 in which the concave portion 5 is formed on the inner peripheral surface as described above, when a foreign object enters between the mating shaft, the foreign material is rotated by the mating shaft or the surface of the resin overlay layer 4. Multiplying into the flow of the lubricating oil supplied to the concave portion 5 easily. For this reason, the generation | occurrence | production of the malfunction that a foreign material is pressed on the sliding surface 4a of the resin overlay layer 4 and a crack is produced | generated, or peeling arises in the crack part can be prevented as much as possible.

  Then, when the foreign matter that has entered the concave portion 5 receives a pressing force from the counterpart shaft or the like, the relatively soft bearing alloy layer 3 is exposed in the concave portion 5, so that the inside of the bearing alloy layer 3 is exposed. It is buried or adheres to the bearing alloy layer 3. For this reason, the generation | occurrence | production of the malfunction that a foreign material rolls in the concave part 5 for a long time and causes a crack, peeling, etc. on the resin overlay layer 4 which comprises the inner surface of the concave part 5 is prevented as much as possible.

In order to confirm the effect of the present invention, a test piece was manufactured and a seizure test was performed.
The test pieces are Examples 1 to 5 and Comparative Examples 1 to 6 having the contents shown in Table 1 below.

  The manufacturing method of the test piece is as follows. First, an Al-based bearing alloy plate constituting the bearing alloy layer is deposited on the steel plate constituting the back metal layer by a pressure welding method to produce a bimetal, and the same as described above on the bimetal bearing alloy layer. Example products 1 to 5 and comparative products 1 to 6 were obtained by forming a resin overlay layer having a thickness of 15 μm by the method.

  For the comparative examples 1 to 4, the resin overlay layer remains formed, and for the examples 1 to 5 and the comparative examples 5 and 6, the cross section V having a depth of 30 μm from the surface of the resin overlay layer is further provided. The cutting which forms a letter-shaped concave part was performed.

  The seizure test was performed under the conditions shown in Table 2 for the above-described Example Products 1 to 5 and Comparative Example Products 1 to 6. In the seizure test, the surface pressure applied to the sample was increased by 1 MPa every 10 minutes, and the surface pressure that resulted in seizure was listed in Table 1 as the seizure surface pressure. In addition, the foreign material shown to 2nd type of JISZ8901 is a silica sand with an average particle diameter of 27-31 micrometers.

  As understood from the seizure test results, the example products 1 to 5 have higher non-seizure properties than the comparative example products 1 to 6. That is, among the comparative examples 1 to 6, the comparative examples 5 and 6 in which the concave portions are formed have improved non-seizure properties compared with the comparative examples 1 to 4 having no concave portions, but the bearing alloy layer. Since the hardness of the steel exceeds 50 HV, the effect of improving the non-seizure property is not so high. On the other hand, Examples 1 to 5 in which the hardness of the bearing alloy layer is 50 HV or less show a high non-seizure improvement effect, and it is understood that high non-seizure can be obtained by implementing the present invention. . That is, it can be seen that a very excellent non-seizure property can be obtained only by a synergistic effect of the recessed portion extending in the sliding direction and the exposed bearing alloy layer of 50 HV or less.

  In addition, the recessed part 5 is not restricted to said embodiment. For example, the cross-sectional shape of the concave portion 5 is not limited to the V shape, but may be a rectangular shape as shown in FIG. 4A, or a semicircular shape as shown in FIG. Further, as shown in FIG. 4C, the depth of the concave portion 5 is the same as the thickness of the resin overlay layer 4, and the surface of the bearing alloy layer 3 is formed on the bottom surface of the concave portion 5. It may be exposed. For example, in a plain bearing whose sliding direction is the axial direction, it is preferable to form a concave portion extending in the axial direction.

Sectional drawing of the slide bearing which shows one Embodiment of this invention (A) is a perspective view of a plain bearing, (b) is a partially enlarged side view. Diagram showing the manufacturing process of plain bearings Sectional drawing which shows other embodiment of a recessed part

Explanation of symbols

In the drawings, 1 is a slide bearing, 2 is a back metal layer, 3 is a bearing alloy layer, 4 is an overlay layer, and 5 is a concave portion.

Claims (1)

In a slide bearing having a cylindrical shape or a half shape, and having a bearing alloy layer and a resin overlay layer containing a solid lubricant provided on the bearing alloy layer on the inner periphery,
The bearing alloy layer has a hardness of 50 HV or less,
A concave portion extending in the circumferential direction and having a depth from the sliding surface of the resin overlay layer to at least the surface of the bearing alloy layer is formed in the inner peripheral portion, and the bearing alloy layer is formed in the concave portion. Exposed,
A plain bearing characterized by that.

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