JP5676305B2 - Chain guide and chain tensioner device - Google Patents

Description

  The present invention relates to a chain guide and a chain tensioner device that apply tension to a chain that is stretched endlessly so that the chain is not slackened.

  In the chain tensioner device, a chain guide that contacts the chain is installed in the middle of the chain spanned endlessly between the drive sprocket and the driven sprocket, and at least one of the chain guides is set substantially perpendicular to the traveling direction of the chain. By applying pressure, tension is applied so that slack does not occur in a chain that travels at high speed, and it is used in a timing chain of an engine valve drive device.

  Since the chain guide is guided while being in contact with the chain, there arises a problem that sliding resistance due to friction is generated between the chain guide and noise and mechanical loss increase.

  As a technique for suppressing the noise and mechanical loss of the chain guide, those described in Patent Document 1 or Patent Document 2 are known. The chain guides described in these documents are formed in a curved shape along the running direction of the chain, and a roller is disposed on the sliding surface portion that comes into contact with the chain, and the roller is pressed against the chain running at high speed while rolling. Thus, sliding resistance is reduced.

JP-A-9-236157 JP 2010-180900 A

  By the way, in the chain guide described in these documents, since the chain and the roller come into contact with each other with a strong frictional force, it is required to improve the strength of the roller in contact with the chain and reduce the sliding resistance.

  In addition, since the chain guide contacts the chain at a high speed, it is also required that the chain guide be low noise and have little vibration.

  In order to solve the above problems, the present invention has high strength of the contact surface with the chain and low sliding resistance. It is an object to provide a small number of chain guides and a chain tensioner device using the same.

  In order to solve the above-described problems, the present invention is provided along the traveling direction of a plurality of rollers that contact an endlessly spanned chain and a chain that supports both ends of the support shafts of the plurality of rollers. In the chain guide composed of the opposing side plate members, the roller is a chain that covers the support shaft, a needle roller bearing that includes an outer ring provided on an outer peripheral surface of the support shaft, and an outer periphery of the outer ring. It is characterized by comprising an iron outer ring in contact with.

  As the needle roller bearing, there can be used a roller comprising a steel outer ring having inward flanges at both ends and a roller with a cage incorporated in the outer ring.

  The steel outer ring is formed by press molding, but may be formed by cut-out molding.

  It is preferable that the iron outer ring has a hardness higher than that of the chain so that it does not easily wear even when a chain running at high speed comes into contact.

  As the material for the iron outer ring, for example, a material that can be cured, such as SUJ2 or SCM, is preferable.

  The thickness of the iron outer ring is preferably 1 mm or more in order to prevent deformation and improve strength.

  The bus outer shape of the iron outer ring is preferably a drum shape or a straight shape in order to avoid local high surface pressure due to point contact with the chain.

  It is preferable to form minute irregularities on the surface of the iron outer ring in order to improve the lubricating oil retention performance.

  Further, the surface of the iron outer ring may be subjected to nitriding treatment to improve the strength.

  The roundness of the iron outer ring is preferably 20 μm or less in order to reduce vibration and achieve quietness.

  At least two chain guides according to the present invention are arranged in the middle of an endlessly spanned chain, and one chain guide is supported at one end by a rotating shaft and the other end is swung by a pressing device. By constructing so that tension is applied to the chain and one other chain guide is configured so that both ends are fixed and pressed against the chain, an excellent chain tensioner device with less mechanical loss can be obtained. .

  In the chain guide of the present invention, the portion of the roller that comes into contact with the chain is an iron outer ring. Therefore, the chain guide has high strength and is not easily worn even when the chain running at high speed comes into contact. In addition, since a needle roller bearing is disposed between the iron outer ring and the support shaft, the sliding resistance is small, and since the iron outer ring is fitted on the outer periphery of the steel outer ring, High circularity, low noise, and little vibration.

It is a perspective view showing one embodiment of a chain guide concerning this invention. It is the top view which looked at the chain guide of FIG. 1 from the chain side. It is a front view of the chain guide of FIG. It is a front view which shows embodiment of the top view which shows the state which removed the roller from the chain guide of FIG. It is sectional drawing of the AA line of FIG. It is the elements on larger scale of FIG. It is a transverse cross section showing one embodiment of a chain guide concerning this invention. It is a cross-sectional view showing another embodiment of the chain guide according to the present invention. It is a front view which shows an example of the chain tensioner apparatus which uses the chain guide which concerns on this invention.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated in order to avoid duplication of description.

  The chain guide according to the embodiment of the present invention is used, for example, to apply tension to a timing chain of an engine valve drive system.

  As shown in FIG. 9, the timing chain 1 includes a crank sprocket 2 attached to the crankshaft, a first cam sprocket 3 attached to the first camshaft of the valve operating mechanism, and a second cam sprocket attached to the second camshaft. 4 is wound endlessly.

  The timing chain 1 between the crank sprocket 2 and the first cam sprocket 3 and between the crank sprocket 2 and the second cam sprocket 4 has a first chain guide 5a and a second chain guide 5b so that the timing chain 1 does not loosen. Is arranged.

  The first chain guide 5a is configured such that one end side in the longitudinal direction is rotatably supported by the engine by the rotating shaft 6 and the other end side is swung by the pressing device 7 to apply tension to the timing chain 1. .

  The second chain guide 5b is fixed so that both ends in the longitudinal direction are fixed to the engine by the mounting shaft 8 so that the tensioned timing chain 1 is not loosened.

  The first chain guide 5a and the second chain guide 5b are different in that the first chain guide 5a is swung by the pressing device 7 whereas the second chain guide 5b is fixed to the engine without swinging. Since the basic structure for guiding the timing chain 1 is the same, only the chain guide 5 will be described hereinafter. The chain guide 5 is also referred to as a chain lever.

  The chain guide 5 includes a pair of side plate members 9 formed in a curved shape along the timing chain 1 and a column member 10 that connects the side plate members.

  Furthermore, through holes 11 are provided at both longitudinal ends of the side plate member 9. A shaft (not shown) is inserted into the through hole 11 and attached to the inner wall of the engine cover, for example.

  Like the first chain guide 5a, one end side in the longitudinal direction is rotatably supported by the engine by a rotating shaft, and the other end side is swung by the pressing device 7 to apply tension to the timing chain 1. In that case, the through hole 11 of the side plate member 9 may be provided only on one end side in the longitudinal direction.

  The pressing device 7 that presses the first chain guide 5a may be a mechanical type that presses with a spring or a screw, or a hydraulic type that presses with hydraulic pressure.

  The pair of side plate members 9 have a predetermined interval in the width direction, and a plurality of rollers 12 that contact the timing chain 1 are arranged between the side plate members 9. The rollers 12 may be arranged at a uniform pitch with respect to the curved side plate member 9 or may be different in pitch so that many rollers 12 are arranged on the entrance side of the timing chain 1 in the running direction. Good.

  On the opposing wall surface of the side plate member 9, support recesses 14 that support both ends of the support shaft 13 of the roller 12 are provided.

  As shown in FIGS. 4, 5, and 6, the support recess 14 includes an insertion recess 14 a that opens to the end surface on the timing chain 1 side, and an end of the support shaft 13 that is continuous with the insertion recess 14 a. The both ends of the support shaft 13 of the roller 12 are inserted into the fixed recess 14b from the insertion recess 14a, and the both ends of the side plate member 9 are inserted into the fixed recess 14b. I support it.

  As shown in FIG. 5, a plurality of the support recesses 14 are arranged along the curved shape of the side plate member 9, and the column member 10 is disposed between the support recess 14 and the support recess 14.

  As shown in the enlarged view of FIG. 6, the insertion recess 14a is formed in a tapered shape having a wide opening a and gradually narrowing to a position reaching the fixed recess 14b. The width dimension of the insertion port b at a position where it is connected to the location 14b is smaller than the diameter φ of the arc-shaped fixed recess 14b.

  A diameter φ of the arc-shaped fixed recess 14b is formed to be smaller than the diameter of the support shaft 13, and the support shaft 13 is press-fitted and fixed to the fixed recess 14b.

  Further, as shown in FIGS. 1 and 2, the support recess 14 is formed in the side plate member 9 in a non-penetrating state. Thereby, the movement of the inserted support shaft 13 in the axial direction is restricted.

  In this embodiment, the side plate member 9 and the column member 10 are integrally formed by resin molding using, for example, polyamide (PA) 46 or polyamide (PA) 66 which is a polymer obtained by polycondensation of diaminobutane and adipic acid. Is done. Moreover, in order to increase mechanical strength, the thing which compounded glass fiber and carbon fiber in PA46 and PA66 can also be used.

  Weight reduction can be achieved by forming the side plate member 9 and the column member 10 with resin. Moreover, the resin which forms with the side plate member 9 and the column member 10 can use a highly heat conductive thing in order to thermally radiate frictional heat.

  In addition, the side plate member 9 and the column member 10 can be formed by casting or die casting using a light metal such as aluminum or magnesium other than the resin.

  As shown in FIG. 7, the roller 12 contacts the support shaft 13, a needle roller bearing having a steel outer ring 12 a, and the timing chain 1 covered on the outer peripheral surface of the steel outer ring 12 a. The outer ring 12d is made of iron.

  The needle roller bearing is a shell-type radial needle roller bearing including a steel outer ring 12a having inward flanges at both ends and a roller 12c with a cage 12b incorporated in the outer ring 12a. . Cost reduction and weight reduction can be achieved by using the shell type.

  The outer ring 12a can be formed by press molding or scraping molding.

  When the outer ring 12a is formed by press molding, it is preferable that the inward flanges at both ends are subjected to edge bending after the cage 12b and 12c are assembled, and heat-treated after assembly.

  Further, the higher the hardness of the iron outer ring 12d than the hardness of the timing chain 1, it is possible to prevent wear.

  As the material of the iron outer ring 12d, a material that can be hardened by heat treatment, such as SUJ2 or SCM, is used.

  Minute irregularities may be formed on the surface of the iron outer ring 12d in order to improve the lubricating oil retention performance.

  Further, the surface of the iron outer ring 12d may be nitrided to improve the strength.

  The generatrix shape on the surface of the iron outer ring 12d is preferably a drum shape or a straight shape in order to avoid local surface pressure due to point contact with the timing chain 1.

  The roundness of the iron outer ring 12d is preferably 20 μm or less in order to reduce vibration and achieve quietness.

  The thickness of the iron outer ring 12d is preferably 1 mm or more in terms of strength.

  The rollers 12c are held at a predetermined interval in the circumferential direction by a cage 12b. As the cage 12b, a V-type cage having a V-shaped column part is used. By using the cage 12b, the skew of the roller 12c can be prevented, the end surface of the roller 12c can be prevented from directly touching the flange portion of the outer ring 12a, and wear of the side plate member 9 can be prevented. In addition, you may comprise with the rolling bearing of the full roller structure which does not use the holder | retainer 12b.

  Next, in order to assemble the roller 12 to the opposing side plate member 9, first, as shown in FIG. 5, a roller 12 fitted with a support shaft 13 is prepared. Then, both ends of the support shaft 13 of the roller 12 face the insertion recess 14a of the support recess formed on the opposing wall surface of the side plate member 9, and are fixed into the insertion recess 14a by dropping into the insertion recess 14a. Insert into the recess 14b. In this embodiment, since the opening a is wide and the insertion recess 14a is formed in a taper shape, when the support shaft 13 is inserted, the support shaft 13 can be easily moved from the opening a through the insertion port b. It can be guided to the arcuate fixed recess 14b.

  According to the above embodiment, since the diameter φ of the arc-shaped fixed recess 14b is smaller than the diameter of the support shaft 13, the support shaft 13 is press-fitted and attached to the fixed recess 14b. As a result, the rotation of the support shaft 13 can be suppressed. Moreover, since the width of the insertion port b connected to the fixed recess 14b is smaller than the diameter φ of the arc-shaped fixed recess 14b, the insertion port b functions to prevent the support shaft 13 from coming off. Furthermore, since the support recess 14 is formed so as not to penetrate the side plate member 9, it is possible to restrict the axial movement of the support shaft 13 to be inserted.

  Next, with the support shaft 13 of the roller 12 fitted in the support recess 14 of the opposing side plate member 9, as shown in FIGS. 1, 3, 4, and 7, The iron outer ring 12 d is lower than the end face of the side plate member 9. Thereby, the timing chain 1 is guided between the opposing wall surfaces of the side plate member 9 while being in contact with the iron outer ring 12 d, thereby preventing the traveling timing chain 1 from coming off from the opposing wall surface of the side plate member 9.

  Moreover, the height to the end surface of the iron outer ring 12d constituting the roller 12 and the side plate member 9 is lower than the position of the connecting pin 1b connecting the plate 1a constituting the timing chain 1, as shown in FIG. It is desirable to do. When the height between the iron outer ring 12d and the end face of the side plate member 9 is higher than the position of the connecting pin 1b that connects the plate 1a constituting the timing chain 1, the connecting pin 1b faces the opposing wall surface of the side plate member 9. This is not preferable.

  Next, FIG. 8 is a cross-sectional view showing a chain guide 5 according to another embodiment of the present invention. About this embodiment, about the structure which is common in embodiment mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted and a different structure is demonstrated below. In this embodiment, as shown in FIG. 8, an oil hole 15 is provided at the center of the support shaft 13, and a discharge hole 15 a through which oil is discharged is provided at a position opposite to the timing chain 1. The side plate member 9 is provided with a hole 16 that is continuous with the oil hole 15. Thus, by providing the oil hole 15, oil can be supplied into the bearing. In addition, heat can be released. As described above, the direction of the discharge hole 15a of the oil hole 15 is preferably opposite to that of the timing chain 1, so that the oil is smoothly supplied into the bearing. Further, the support shaft 13 is hollowed by the oil hole 15a, so that the weight can be reduced.

  Further, the chain guide 5 of each embodiment of the present invention can apply tension to various drive chains in addition to the engine timing chain, and can reduce mechanical loss.

  And, as shown in FIG. 9, the chain tensioner device using the chain guide 5 of the present invention is a first chain in which the rotating shaft 6 is inserted into the through hole 11 at one end and the other end side is swung by the pressing device 7. The guide 5a and the second chain guide 5b, both ends of which are fixed to the engine by the mounting shaft 8, are configured. According to this chain tensioner device, the mechanical loss of the engine timing chain can be reduced and the weight thereof can be reduced, and the fuel consumption rate can be improved.

  The timing chain 1 can be either a roller chain or a silent chain.

  Moreover, although the example which formed the side-plate member 9 and the column member 10 integrally was shown in the above embodiment, you may divide | segment both and form them separately.

  The chain guide according to the present invention is effectively used in a mechanism for applying tension to a drive chain such as an engine.

DESCRIPTION OF SYMBOLS 1 Timing chain 2 Crank sprocket 3 1st cam sprocket 4 2nd cam sprocket 5 Chain guide 5a 1st chain guide 5b 2nd chain guide 6 Rotating shaft 7 Pressing device 8 Mounting shaft 9 Side plate member 10 Column member 11 Through-hole 12 Roller 12a Outer ring 12b Cage 12c Roller 12d Iron outer ring 13 Support shaft 14 Support recess 14a Insert recess 14b Fixed recess 15 Oil hole 15a Discharge hole 16 hole

Claims (12)

  In a chain guide comprising a plurality of rollers in contact with an endlessly spanned chain and opposing side plate members provided along the traveling direction of the chain that supports both ends of the support shafts of the plurality of rollers, The roller is constituted by the support shaft, a needle roller bearing having an outer ring provided on the outer peripheral surface of the support shaft, and an iron outer ring that contacts the chain and is placed on the outer periphery of the outer ring. And chain guide.   The chain guide according to claim 1, wherein the needle roller bearing includes a steel outer ring having inward flanges at both ends, and a roller with a cage incorporated in the outer ring.   The chain guide according to claim 1 or 2, wherein the steel outer ring is formed by press molding.   The chain guide according to claim 1 or 2, wherein the steel outer ring is formed by machining.   The chain guide according to any one of claims 1 to 4, wherein the hardness of the iron outer ring is higher than the hardness of the chain.   The chain guide according to any one of claims 1 to 5, wherein a bus bar shape of the iron outer ring is a drum shape or a straight shape.   The chain guide according to any one of claims 1 to 6, wherein minute irregularities for improving the retention performance of the lubricating oil are formed on the surface of the iron outer ring.   The chain guide according to any one of claims 1 to 7, wherein a thickness of the iron outer ring is 1 mm or more. The chain guide according to any one of 1 to 8 , wherein a surface of the iron outer ring is nitrided. The chain guide according to any one of claims 1 to 9 , wherein the roundness of the iron outer ring is 20 µm or less. A chain tensioner device in which the chain guide according to any one of claims 1 to 10 is arranged in the middle of an endlessly stretched chain. At least two chain guides according to any one of claims 1 to 10 are arranged in an intermediate portion of a chain that is stretched endlessly, and one chain guide is supported at one end by a rotating shaft, and the other end is at the other end. A chain tensioner device configured to swing by a pressing device and apply tension to the chain, and the other one chain guide is configured such that both ends are fixed and pressed against the chain.

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