JP2019203553A - Half-split bearing and bearing - Google Patents

Abstract

To provide a bearing having fatigue resistance, wear resistance, and foreign matter resistance in an improved balance.SOLUTION: A half-split bearing according to one embodiment has a lining layer formed of a copper alloy and having a hardness of 120HV0.2 or less, and a coating layer that is formed on the lining layer, contains at least a binder resin, and has a surface roughness of 0.6 μmRa or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bearing.

  A sliding member having a resin coating layer formed on a substrate is known. For example, Patent Document 1 describes a sliding member in which a coating layer containing a binder resin and Fe2O3 is formed on a substrate.

Special table 2012-514170 gazette

  The technique described in Patent Document 1 also has room for improvement in the balance of fatigue resistance, wear resistance, and foreign matter resistance. In contrast, the present invention provides a bearing with an improved balance of fatigue resistance, wear resistance, and foreign matter resistance.

  The present invention includes a lining layer formed of a copper-based alloy and having a hardness of 120 HV 0.2 or less, and a coating layer formed on the lining layer and including at least a binder resin and having a surface roughness of 0.6 μm Ra or less. Provide half bearings.

  The lining layer may have a hardness of 100 HV 0.2 or less.

  The surface roughness of the coating layer may be 0.2 μm Rz JIS or less.

  The copper-based alloy may include 0.5 to 15% by mass of Bi and 1 to 15% by mass of Sn.

  In addition, the present invention has a first half bearing and a second half bearing to which a load lower than that of the first half bearing is applied, and the first half bearing is made of an aluminum-based alloy. The second lining bearing has a first lining layer and a first coating layer containing at least a binder resin, and the second half bearing is made of a copper-based alloy and has a hardness of 120 HV or less, and the second lining. Provided is a bearing having a second coating layer formed on the layer and containing at least a binder resin and having a surface roughness of 0.6 μmRa or less.

  According to the present invention, it is possible to provide a bearing with an improved balance of fatigue resistance, wear resistance, and foreign matter resistance.

The figure which illustrates the structure of the bearing 1 which concerns on one Embodiment. The figure which illustrates the cross-section of the half bearing 2 (and half bearing 3). The figure which shows the conditions of a foreign material injection | throwing-in test. The figure which shows the conditions of a one-piece test.

1. Structure FIG. 1 is a diagram illustrating a structure of a bearing 1 according to an embodiment. The bearing 1 is a sliding bearing in which a half bearing 2 and a half bearing 3 are combined. The bearing 1 is a so-called connecting rod bearing used in, for example, a connecting rod. The half bearing 2 is an upper half bearing (an example of a first half bearing), and the half bearing 3 is a lower half bearing (an example of a second half bearing). A load higher than that of the half bearing 3 is applied to the half bearing 2. The application of the bearing 1 is not limited to the connecting rod bearing, but may be used for other applications such as a so-called main bearing.

  FIG. 2 is a diagram illustrating a cross-sectional structure of the half bearing 2 (and half bearing 3). FIG. 2 shows a cross section of the half bearing 2 parallel to the axial direction and perpendicular to the sliding surface. The half bearing 2 has a back metal 21, a lining layer 22, and a coating layer 23. The back metal 21 is a layer for giving the half bearing 2 a shape and mechanical strength, and is formed of, for example, steel, cast iron, or resin.

  The lining layer 22 is a layer for improving sliding characteristics. As the material of the lining layer 22, a material that satisfies the characteristics required for the application of the half bearing 2 (or the bearing 1) is selected. In this example, the lining layer 22 is formed of a copper-based alloy. The copper-based alloy refers to an alloy mainly composed of copper. In one example, this copper-based alloy contains 0.5 to 15% by mass of Bi and 1 to 15% by mass of Sn, with the balance being Cu and inevitable impurities.

  From the viewpoint of improving the foreign matter resistance (foreign matter embedding property), the hardness of the lining layer 22 is preferably 120HV0.2, more preferably 100HV0.2 or less, and 90HV0.2 or less. Is more preferable. Further, by using a copper-based alloy for the lining layer 22, fatigue resistance can be improved as compared with, for example, a half bearing using an aluminum-based alloy for the lining layer. In one example, the thickness of the lining layer 22 is 0.15 to 0.30 mm.

  The coating layer 23 is a layer for improving sliding characteristics. As the material of the coating layer 23, a material that can satisfy the characteristics required for the application of the half bearing 2 (or the bearing 1) is selected. In this example, the coating layer 23 includes at least a binder resin. As the binder resin, for example, a thermosetting resin is used. Specifically, the binder resin is at least one of a polyamide-imide (PAI) resin, a polyimide (PI) resin, a polyamide resin, an epoxy resin, a phenol resin, a polyacetal resin, a polyether catheter ketone resin, and a polyphenylene sulfide resin. Including.

  The coating layer 23 may include an additive dispersed in the binder resin in addition to the binder resin. The additive includes, for example, at least one of a solid lubricant, a soft material, a hard material, and a coupling agent.

  Solid lubricant is added to improve the friction properties. The solid lubricant includes, for example, at least one of MoS2, WS2, polytetrafluoroethylene (PTFE), graphite, h-BN, and SB2O3. For example, MoS2 gives good lubricity. Further, PTFE has an effect of reducing the friction coefficient because of its low intermolecular cohesion. In addition, graphite improves wettability and improves initial conformability. The initial conformability is a property of improving the slidability when the sliding surface wears and becomes smooth when slidably contacting with the counterpart material after the start of sliding. When the slidability is improved by the expression of the initial conformability, the wear amount of the entire sliding layer is reduced.

The soft material is added in order to improve the foreign material burying property. The soft material includes, for example, at least one of Sn, Al, or Bi. Hard materials are added to improve wear resistance. The hard material includes, for example, at least one of SiC, Al2O3, TiN, AlN, CrO2, Si3N4, ZrO2, and Fe3P.

  The coupling agent is added to reinforce the bond between the binder resin and the base material (lining layer 22). For example, a silane coupling agent is used as the coupling agent.

  From the viewpoint of improving the foreign matter resistance, the surface roughness of the coating layer 23 is preferably 0.6 μmRa or less, more preferably 0.4 μmRa or less, and further preferably 0.2 μm or less. Further, by using a coating material containing a resin for the coating layer 23, for example, wear resistance can be improved as compared to a half bearing using plating as the coating material.

  In one example, the coating layer 23 includes 35 to 55% by mass of polyamideimide (PAI), 43 to 63% by mass of graphite (Gr.), And 0.1 to 10% by mass of SiC, with the remainder being inevitable impurities. Composed. Note that SiC may be replaced with another hard material, or no hard material may be added. In one example, the thickness of the coating layer 23 is 0.001 to 0.02 mm.

  The half bearing 3 also has the same cross-sectional structure as the half bearing 2. However, in this example, the material of the lining layer 32 is softer than that of the lining layer 22. In one example, the material of the lining layer 32 is an aluminum-based alloy. An aluminum-based alloy refers to an alloy mainly composed of aluminum. In one example, this aluminum-based alloy contains 1 to 15% by mass of Sn and 1 to 8% by mass of Si, with the balance being composed of Al and inevitable impurities. By using an aluminum-based alloy for the lining layer 32, the foreign matter resistance can be improved as compared with, for example, a lining using a copper-based alloy.

2. Experimental Example The inventors of the present application actually produced a sample for the bearing described above. The inventors further tested physical properties and mechanical properties of these samples. In the following, in the experimental examples, samples having specific dimensions, raw materials, and compositions were prepared, but these are merely examples, and the present invention is not limited to these.

2-1. Sample Table 1 shows the composition (mass%) of the lining layer 22 and the coating layer 23 of the half bearing 2 on the upper side for two samples (samples 1 and 2) prepared by the inventors of the present application. None of the samples intentionally includes materials other than those listed in the table (however, materials not listed in the table may be included as inevitable impurities). As described in Table 1, the lining layer is formed of a copper-based alloy in any sample. In the coating layer, PAI was used as a binder resin. As the solid lubricant, graphite (sample 1), BN (sample 2), or MoS2 (sample 3) was used. As other additives, SiC (sample 1) or Fe2O3 (sample 2) was used.

2-2. Hardness Test The inventors conducted a hardness test of the lining layer for Samples 1 and 2. The hardness test was based on “JIS Z 2244-Vickers hardness test test method”. The test was conducted with a test force of 200 g. The test results are as follows.
Sample 1: 90HV0.2
Sample 2: 150HV0.2

2-3. Surface Roughness Test The inventors performed a surface roughness test on Samples 1 and 2. Here, the arithmetic average roughness Ra was measured as the surface roughness. For the measurement, a surface step meter (SE-3400, manufactured by Kosaka Laboratory Ltd.) was used. The test results are as follows.
Sample 1: 0.146 μm Ra
Sample 2: 0.733 μm Ra

2-4. Foreign Object Injection Test FIG. 3 is a diagram showing the conditions of the foreign material input test. The inventors conducted a foreign matter insertion test on bearings A to C using Samples 1 and 2 as upper side (load side) half bearings (an example of second half bearings). The foreign material insertion test is a test in which the bearing pressure is measured by sliding the bearing against the counterpart shaft while supplying lubricating oil mixed with foreign material. The test was conducted under the following conditions.
Bearing load: Step up by 3.6 MPa (every 3 minutes)
Rotational speed: 6000 rpm (sliding speed: 15.01 m / s)
Lubricating oil temperature: 160 ° C
Mating shaft: Hardened steel Bearing shape: φ47.8mm × 17.5mm
Foreign object: Iron piece (1mm x 0.6mm x 0.1mm)

In the bearings A to C, the following was used as the lower side (non-load side) half bearing (an example of the first half bearing) combined with the sample 1 or 2.

The seizure surface pressure obtained as a result of the foreign matter insertion test is as follows. The bearings A and C were tested twice and the bearing B was tested three times. The following surface pressure is the average value.
Bearing A: 77.4 MPa
Bearing B: 54.0 MPa
Bearing C: 46.8 MPa

  When bearing A and bearing B are compared, in the upper side half bearing, a half bearing using a lining layer made of a softer material and a coating layer having a smaller surface roughness (flat) is adopted. Thus, it can be seen that the foreign matter resistance has been improved. Further, when comparing the bearing A and the bearing C, it can be seen that the foreign matter resistance is improved by using a half bearing using an aluminum-based alloy as a lining layer on the lower side (non-load side).

2-5. Per-piece test FIG. 4 is a diagram showing conditions for a single-piece test. The inventors performed a one-piece test on Samples 1 and 2 using a bearing in which two half bearings were combined. In the one-piece test, the mating shaft 51 is supported by the support bearings 52 and 53 and the bearing 1 to be tested, and the mating shaft 51 is slid relative to the center of these bearings to measure the seizure surface pressure. It is a test to do. The bearing 1 is a connecting rod 54 bearing. The test was conducted under the following conditions.
Testing machine: Static load testing machine Lubricating oil temperature: 140 ° C
Load: Step up by 3kN (every 3 minutes)
Rotation speed: 8000rpm
Tilt angle: 0.2 °

The seizure surface pressure obtained as a result of the one-piece test is as follows. Each sample was tested three times. The following surface pressure is the average value.
Sample 1: 42 MPa
Sample 2: 15 MPa

  When sample 1 and sample 2 are compared, sample 1 has better performance per one piece (per piece resistance). This is also considered to be an effect of using a soft material for the lining layer of the half bearing on the load side.

DESCRIPTION OF SYMBOLS 1 ... Bearing, 2 ... Half bearing, 3 ... Half bearing, 21 ... Back metal, 22 ... Lining layer, 23 ... Coating layer, 32 ... Lining layer, 51 ... Opposite shaft, 52 ... Support bearing, 53 ... Support bearing, 54 ... Connecting rod

Claims (5)

A lining layer formed of a copper-based alloy and having a hardness of 120HV0.2 or less;
A half bearing having a coating layer formed on the lining layer and containing at least a binder resin and having a surface roughness of 0.6 μmRa or less. The half bearing according to claim 1, wherein the lining layer has a hardness of 100 HV 0.2 or less. The half bearing according to claim 1, wherein the coating layer has a surface roughness of 0.2 μm Rz JIS or less. The half bearing according to any one of claims 1 to 3, wherein the copper-based alloy includes 0.5 to 15 mass% Bi and 1 to 15 mass% Sn. A first half bearing;
A second half bearing that receives a lower load than the first half bearing;
The first half bearing is
A first lining layer formed of an aluminum-based alloy;
A first coating layer containing at least a binder resin,
The second half bearing is
A second lining layer formed of a copper-based alloy and having a hardness of 120 HV or less;
A bearing having a second coating layer formed on the second lining layer and including at least a binder resin and having a surface roughness of 0.6 μmRa or less.

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