JP2005114080A - Chain having damping property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the noise generated from a chain and to simplify a constitution and a manufacturing process. <P>SOLUTION: This timing chain 26 used as a power transmitting means in an engine includes a damping alloy body substantially including Al of 6-10 wt.% and Fe as a residual part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a metal chain such as a timing chain used in an engine timing system as an example.

  In an automobile engine, a camshaft is disposed on an upper portion of a cylinder head, a cam housing is provided to rotatably support the camshaft, and a valve operating device is provided in which the cam housing is fixed to the cylinder head by a housing mounting bolt. It has been.

  In such a valve operating apparatus, a timing chain may be provided to transmit the rotation of the crankshaft of the engine to the camshaft. Conventionally, this timing chain is formed of steel as shown in Patent Document 1 below, and is wound around sprockets provided on the crankshaft and the camshaft, respectively.

Special Table 2002-516924 (8th and 47th paragraphs)

  Conventionally, steel is used as the material for such a timing chain, so there is a lot of noise due to contact between the timing chain and the sprocket, friction between the timing chain link plate, pin, roller, bush, etc. Has occurred. In order to prevent such noise, various silent chains have been conventionally used. As an example, such a silent chain has a configuration in which a plurality of link plates are stacked, or a low friction process is performed on the surface of a chain bush, pin, or the like to reduce noise.

  Therefore, the conventional silent chain has problems such as a complicated configuration and a complicated manufacturing process.

  The present invention was made paying attention to such an unsolved problem of the conventional technology, and can suppress the noise generated from the chain, can improve the environment related to noise, An object of the present invention is to provide a chain having vibration damping properties that can simplify the structure and the manufacturing process.

  According to the present invention, the metal chain used as the power transmission means is substantially configured to include a vibration damping alloy body including Al: content of 6 to 10% by weight and the balance Fe. The most important feature.

  Since the present invention has such a configuration, the following actions can be realized. Since the damping alloy body included in the present invention is a ferromagnetic material, the main vibration damping mechanism is due to magnetic / mechanical hysteresis loss accompanying the irreversible movement of the domain wall. As a result, the mechanism of vibration absorption in the present invention is realized by the vibration suppressing action due to the magnetic / mechanical history loss accompanying the irreversible movement of the domain wall of the vibration entering the damping alloy body from the outside.

  In the present invention, since the metal chain is formed of a damping alloy body that itself has a damping action, it is possible to prevent a situation in which a large noise is generated from the chain that is driven to travel, and to improve the environment related to the noise. it can. Compared to the conventional technology with a multi-layered link plate, which is well-known as a silent chain, and the conventional technology in which low friction processing is applied to the bush and pins of the chain, the structure is simplified and the manufacturing process is simplified. be able to.

  The chain is configured to substantially include a vibration damping alloy body including Al: content 6 to 10% by weight and the balance Fe.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a valve operating device for a cylinder head according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the engine as viewed from the section line X2-X2 of FIG. 1, and FIG. FIG. 4 is a cross-sectional view of the engine viewed from the plane line X3-X3, and FIG. 4 is a graph for explaining the operation of this embodiment.

  Hereinafter, the valve operating mechanism according to the present embodiment will be described with reference to FIGS. In the engine 2, a cylinder head 6 is installed above the cylinder block 4. A crankshaft 8 is rotatably supported at the lower part of the cylinder block 4. A crank sprocket 10 is fixedly attached to one end of the crankshaft 8.

  In the upper part of the cylinder head 6, intake and exhaust camshafts 14 and 16 are arranged so as to be separated from each other in the left-right direction in FIG. Intake and exhaust cam sprockets 18 and 20 are fixedly attached to the intake and exhaust camshafts 14 and 16, respectively. A cylinder head cover 22 is attached to the cylinder head 6.

  A timing chain sprocket 24 is attached to one end portion of the intake camshaft 14. The crank sprocket 10 and the timing chain sprocket 24 are provided with a timing chain 26 as an embodiment of the chain of the present invention. A cam chain 28 is wound around the intake cam sprocket 18 and the exhaust cam sprocket 20.

  An oil pump chain sprocket 30 having the same diameter as that of the crank sprocket 10 is provided on one end side of the crankshaft 8. The oil pump chain 32 wound around the oil pump chain sprocket 30 is wound around an oil pump sprocket (not shown) of an oil pump (not shown).

  In the present embodiment, the timing chain of the present invention is configured including the timing chain 26, the cam chain 28 and the oil pump chain 32. In the following description, the timing chain 26 is illustrated, but the effects of the present invention to be described later with respect to the timing chain 26 are also realized with respect to the cam chain 28 and the oil pump chain 32.

  The outer link plate 35, the inner link plate 36, the pin 37, the bush and the roller (not shown) constituting the timing chain 26 are formed from the above-described vibration-damping alloy body through various press processes. Here, the damping alloy body has an Al content of 6 to 10% by weight, Fe and unavoidable impurities (Si 0.1% by weight or less; Mn 0.1% by weight or less; other C, N, S, And 0.1% by weight or less). In addition, the average grain size of the crystal of the damping alloy body is manufactured to be in the range of 300 to 700 μm.

  Since such a damping alloy body is a ferromagnetic material, a vibration damping mechanism can be realized by magnetic / mechanical hysteresis loss due to irreversible movement of the domain wall due to externally applied vibration. Thereby, the noise generated when the timing chain 26 contacts the crank sprocket 10, the timing chain sprocket 24, etc. can be suppressed, and the environment related to noise can be improved.

  Further, according to the present invention, the material of the timing chain 26 has a vibration damping property such as a sandwich steel plate, but the necessity of using an existing material having a complicated configuration is eliminated, and the configuration is simplified and the number of parts is reduced. Can be planned.

  Compared to conventional technologies such as a silent chain with a multi-layer link plate and a timing chain with low friction processing on bushes and pins, the structure and manufacturing process can be simplified. .

  The vibration damping alloy body can be manufactured as follows. First, Al and Fe material adjusted in advance to a ratio in which the Al content in the alloy after manufacture becomes a predetermined value, nitrogen and acid <DP N = "0003"> <TXF LY = "0300" LX = "0200 "WI =" 080 "HE =" 180 "FR =" 0001 "> In order to prevent the intrusion of the element, it is melted under a reduced pressure of about 0.1 to 0.01 pA, and then poured into a mold, and Al—Fe An alloy ingot is obtained. Next, the obtained alloy ingot is finished into a plastic work material having a predetermined product shape by plastic working such as rolling and forging and machining.

  Next, the obtained plastic working material is kept at a temperature of about 700 to 1000 ° C. for about 30 minutes to 2 hours, and then annealed. The temperature and time during the annealing treatment are appropriately selected from the above ranges in consideration of the alloy composition, plastic working conditions related to the product shape, and the like.

  Next, the annealing rate of the obtained annealed material in a temperature range from a predetermined holding temperature to 600 degrees is, for example, 20 degrees / minute or less (preferably 10 degrees / minute or less, more preferably 1 to 5 degrees / minute). Degree). Natural cooling (cooling) may be performed in a temperature range of less than 600 degrees.

  In this way, the internal strain due to plastic working of the damping alloy body is removed, and an Al—Fe alloy material having an average crystal grain size of 300 to 700 μm is obtained. The average grain size of the crystal can be controlled by the temperature and time during annealing treatment, the slow cooling rate, etc., according to the alloy composition.

  For example, after holding the plastic working material at 850 ° C. for 1 hour, by slowly cooling the plastic working material at a cooling rate in the temperature range of 850 to 600 ° C. at 5 ° / min, a material having a crystal grain size of about 500 to 700 μm is obtained. It is done. Since such a material has a large internal friction, its damping performance is further improved.

  In the present embodiment, even when the lowest natural frequency of the vibration mode of the timing chain 26 matches the resonance frequency of the timing chain 26, the vibration of the timing chain 26 is remarkably suppressed. Due to this resonance, a situation in which high stress is generated in the timing chain 26 is prevented, and fatigue failure in the timing chain 26 can be prevented.

  As another embodiment of the present invention, a configuration example in which a rubber viscoelastic layer is formed by coating and vulcanizing a liquid rubber material on one side or both sides of a damping alloy body constituting the timing chain 26 is also included. The rubber materials that make up the liquid rubber are acrylic rubber, acrylonitrile-butadiene rubber, urethane rubber, ethylene-vinyl acetate rubber, chloroprene rubber, silicon rubber, styrene-butadiene rubber, fluorine rubber, methyl methacrylate-butadiene-styrene rubber, natural rubber, etc. The rubber material is appropriately selected.

  The inventor of the present invention measured the damping coefficient which becomes the damping ability of vibration with respect to two cases of the steel plate and the damping alloy body as a typical contrast. The result is shown by lines L1 and L2 in FIG. As is apparent from FIG. 4, it was confirmed that the vibration damping performance of the timing chain 26 using the vibration damping alloy body of the present invention is significantly improved as compared with the case of using a conventional steel plate.

  The present invention is not limited to the above-described embodiments, and includes a wide variety of modifications without departing from the spirit of the present invention. As an example, the above embodiment has been described as a timing chain related to an engine timing system, but the present invention is not limited to such a specific example, and a chain for transmitting power to the rear wheels of a two-wheeled vehicle or traveling of a bicycle. It can be implemented on a wide variety of chains, such as chains used for transport chains, transport cranes, especially hoist cranes.

It is a top view of the valve operating apparatus of the cylinder head according to the Example of this invention. FIG. 2 is a cross-sectional view of the engine as viewed from a section line X2-X2 in FIG. FIG. 2 is a cross-sectional view of the engine as viewed from a section line X3-X3 in FIG. It is a graph explaining the effect | action of a present Example.

Explanation of symbols

2 Engine 6 Cylinder head 8 Crankshaft 10 Crank sprocket 12 Valve mechanism 18 Intake cam sprocket 20 Exhaust cam sprocket 24 Timing chain sprocket 26 Timing chain 28 Cam chain 30 Oil pump chain sprocket 32 Oil pump chain 35 Outer link plate 36 Inner link plate 37 pins

Claims (1)

A chain having vibration damping characteristics, wherein the metal chain is constituted by including a vibration damping alloy body substantially including Al: content 6 to 10% by weight and the balance Fe.

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