JP5992724B2 - Chain guide and chain transmission - Google Patents

Description

  The present invention relates to a chain guide used for adjusting the tension of a chain or for guiding movement of a chain, and a chain transmission using the chain guide.

  The camshaft drive chain transmission with a timing chain spanned between the drive sprocket attached to the crankshaft and the driven sprocket attached to the camshaft can swing to one side of the slack side chain of the timing chain A chain guide is provided, and the adjustment force of the chain tensioner is applied to the swing side end of the chain guide to tension the timing chain to prevent the chain from loosening and fluttering.

  Further, a chain guide is fixed to the tight chain of the timing chain, and the movement of the timing chain is guided by the fixed chain guide to suppress the fluttering.

  Here, as a chain guide for adjusting the tension of the timing chain or moving guide, there is known a type that guides the surface of the timing chain by sliding contact, but the timing chain has a large moving resistance and a lot of transmission torque crosses. There's a problem.

  In order to solve such a problem, in the present applicant, in Patent Document 1, both ends of a plurality of roller shafts arranged in a curved shape are supported by guide bases extending in the moving direction of the timing chain, A chain guide has been proposed in which a roller comprising a roller bearing is rotatably supported by each of a plurality of roller shafts, and a timing chain is movably guided by the plurality of rollers.

  The above-described chain guide is characterized in that the timing chain is guided by rolling of a plurality of rollers, so that the movement resistance of the timing chain is small and the transmission torque cross is small.

International Publication No. 2010/090139

  By the way, in the chain guide described in Patent Document 1, the oil flows out from the oil outlet of the lubricating device provided in the engine and is scattered, or the oil supplied to the oil supply type chain tensioner is discharged from the tip of the tensioner. The roller bearing is lubricated by the scattered oil adhering to the outer ring of the roller bearing and the outer surface of the roller shaft. However, the oil cannot be smoothly taken into the roller bearing, and the roller bearing is lubricated. The point which should be improved in improving the property was left.

  An object of the present invention is to improve the lubricity of a roller bearing that rolls and guides a timing chain.

  In order to solve the above-described problem, in the chain guide according to the present invention, a guide base that is disposed on a part of the outer periphery of the timing chain and has a pair of opposed side plates that extend long in the moving direction of the timing chain; A shaft end portion is supported by a shaft engaging portion provided at a position opposite to the side plate portion, and a plurality of roller shafts provided at intervals in the length direction of the side plate portion, and each of the plurality of roller shafts A chain guide in which the roller is a roller bearing having an outer ring and a plurality of rollers incorporated inside the outer ring, and a shaft guide in the side plate portion. A configuration was adopted in which oil guide holes penetrating the inner surface and the outer surface of the side plate portion were provided at or around the joint portion.

  Further, in the chain transmission device according to the present invention, the swingable chain that guides the movement of the timing chain over one side of the slack side chain of the timing chain, spanning the timing chain between the drive sprocket and the driven sprocket. In the chain transmission device in which a guide is provided, the adjustment force of the chain tensioner is applied to the swing side end portion of the chain guide, and the swing side end portion is pressed against the timing chain. The above-described chain guide is adopted.

  In the chain transmission device configured as described above, a fixed chain guide for guiding the movement of the timing chain is provided on one side of the tight chain of the timing chain, and the chain guide according to the present invention is used as the fixed chain guide. By adopting, the flutter of the timing chain can be effectively suppressed.

  In the chain transmission device, as in the conventional case, the oil flows out from the oil outlet of the lubrication device provided in the engine and is scattered, or the oil supplied to the oil supply chain tensioner is discharged from the tip of the tensioner. The roller bearing is oil-lubricated with the scattered oil. In this case, the scattered oil adheres to the outer ring outer diameter surface of the roller bearing, the outer diameter surface of the roller shaft, and further to the outer surface of the side plate portion of the guide base.

  At this time, the oil guide hole is formed in the wall surface of the shaft engaging portion formed in the side plate portion and penetrates the outer surface of the side plate portion, so that the oil adhering to the outer surface of the side plate portion is oil guide hole. Then, it flows into the shaft engaging portion or its peripheral portion, travels along the outer diameter surface of the roller shaft, flows into the roller bearing together with the attached oil already attached to the roller shaft, and oil lubricates the roller bearing.

  As described above, the oil adhering to the outer surface of the side plate portion is taken into the roller bearing from the oil guide hole along the outer diameter surface of the roller shaft, so that the roller bearing is effectively oil-lubricated.

  Here, if an oil guide hole is provided on the extended line of the contact portion between the roller in the load region that receives the radial load of the roller bearing and the roller rolling surface formed on the outer periphery of the roller shaft, lubricating oil is contained in the roller bearing. Can be incorporated effectively.

  Also, if the guide base is a resin molded product, or a molded product by light metal casting or die casting such as aluminum alloy or magnesium alloy, oil guide holes can be formed at the time of molding, so post-processing is unnecessary, The processing cost can be reduced.

  Foreign matter may be mixed in the oil that lubricates the roller bearing. When the foreign matter enters the roller bearing, it may be caught between the roller and the roller shaft, and the roller bearing may be damaged. Therefore, the roller bearing employs a sealed roller bearing in which a seal for preventing entry of foreign matter is incorporated in the opening end of the outer ring so that a gap is formed between the inner diameter surface of the outer ring and the outer diameter surface of the roller shaft. Is preferred.

  In the chain guide according to the present invention, the shaft engaging portion communicates with the tapered groove portion extending in the width direction of the side plate portion from the side surface of the side plate portion on the timing chain side, and the shaft end portion of the roller shaft communicating with the narrow end of the tapered groove portion. A narrow shaft support portion, and the narrow portion of the tapered groove portion may be provided with a retaining function for retaining the roller shaft, or on the outer periphery of the shaft end portion of the roller shaft. A flat surface that engages the formed flat surface and prevents the roller shaft from rotating is provided at the opposite position on the inner periphery, and the side surface that is connected to the end of the flat surface and reaches the opening portion is gently outward. The wall surface which inclines and faces the shaft end surface of the roller shaft of the taper groove portion may have a retaining protrusion that engages with the outer periphery of the end of the roller shaft. In any of the shaft engaging portions, it is preferable that the oil guide hole is formed in the tapered groove portion.

  In the present invention, as described above, the outer surface of the side plate portion is provided by providing the oil guide hole penetrating the outer surface of the side plate portion around or around the shaft engaging portion that supports the shaft end portion of the roller shaft. The lubricating oil adhering to the roller bearing can be taken into the roller bearing from the oil guide hole, and the lubricity of the roller bearing can be improved.

  Further, since the lubricity of the roller bearing is improved, sufficient lubrication can be obtained only with the conventional chain lubrication device, so that it is not necessary to separately provide a dedicated lubrication device for the bearing.

Schematic showing the embodiment of the chain transmission according to the present invention 1 is a longitudinal sectional view of the chain guide shown in FIG. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. Sectional drawing which shows the other example of the side plate part of a guide base Sectional view along line VI-VI in FIG. Sectional drawing which shows the other example of a shaft engaging part. Sectional view along line VIII-VIII in FIG. Sectional view showing another example of roller bearing

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a chain transmission for driving a camshaft, and a timing chain is provided between a drive sprocket 2 attached to the shaft end of the crankshaft 1 and a driven sprocket 4 attached to each shaft end of the camshaft 3. 5 is hung.

  The timing chain 5 may be a roller chain or a silent chain.

The crankshaft 1 rotates in the direction indicated by the arrow in FIG. The rotation of the crankshaft 1 causes the timing chain 5 to move in the direction indicated by the arrow in FIG. is a chain guide a ₁ is provided on one side of the slack side chain 5a.

The chain guide A ₁ extends long in the moving direction of the timing chain 5, and its upper end is supported by a fulcrum shaft 10 protruding from the engine block, and can swing around the fulcrum shaft 10. The adjustment force of the chain tensioner 11 is applied to the swing side end and is pressed toward the slack side chain 5a.

A chain guide A ₂ is provided on the other side of the tension chain 5 b in the timing chain 5. The chain guide A ₂ extends in the moving direction of the timing chain 5 similarly to the swingable chain guide A _1, and both ends thereof are fixed by tightening bolts 12 screwed into the engine block. It is supposed to guide the movement of.

Here, the pivotable chain guide A ₁ and the fixed chain guide A _2, is the same configuration, pivotable chain guide A ₁ is an insertion hole for the shaft inserted into one end portion is formed whereas, chain guide a ₂ fixed is only different in that the insertion hole for the bolt inserted into both end portions are formed.

Therefore, here, is described below the structure of the pivotable chain guide A _1, the chain guide A ₂ of the fastening arrangement will be omitted with the same reference numerals to the same parts.

As shown in FIGS. 2 to 4, the chain guide A ₁ includes a guide base 21 extending long in the moving direction of the timing chain 5 and a plurality of roller shafts provided at intervals in the length direction of the guide base 21. 31 and a plurality of chain guide rollers 41 rotatably supported on each of the plurality of roller shafts 31.

  The guide base 21 has a configuration in which a plurality of interval holding plates 23 are formed at intervals in the length direction between a pair of opposed side plate portions 22. The pair of side plate portions 22 has a bow shape, and an insertion hole 24 into which the fulcrum shaft 10 is inserted is formed at the upper end portion thereof.

  A plurality of shaft engaging portions 25 that support the shaft end portions of the roller shafts 31 are provided on the opposing inner surfaces of the pair of side plate portions 22 at intervals in the length direction of the side plate portions 22.

  The shaft engaging portion 25 is a taper groove portion 25a having a wide opening at the outer surface portion and facing the width direction of the side plate portion 22 from the outer surface portion facing the timing chain 5 of the side plate portion 22, and the taper groove portion 25a. And a circular shaft support portion 25b as a closed end portion communicating with the narrow end. The roller shaft 31 is fitted from the tapered groove portion 25a to the shaft support portion 25b and supported by the shaft support portion 25b.

  An oil guide hole 26 penetrating the outer surface of the side plate portion 22 is formed in the tapered groove portion 25 a on the wall surface facing the shaft end surface of the roller shaft 31.

Here, the tapered groove portions 25a _{D 1} the width of the narrow portion of the inner diameter of _{D 2} of the shaft support portion 25b, when the outer diameter of the roller shaft 31 and _{d, d> D 2> D} 1 relationship holds dimensional relationship The roller shaft 31 is pushed into the shaft support portion 25b from the taper groove portion 25a to be fitted and supported with a tightening margin on the shaft support portion 25b, and is prevented from being removed by the narrow portion of the taper groove portion 25a. ing.

  The plurality of shaft engaging portions 25 have an arcuate arrangement in which a line connecting the centers of the shaft support portions 25b draws a convex arcuate line, but may be a curved arrangement.

  The guide base 21 having the above configuration is a molded product of synthetic resin, and an oil guide hole 26 is formed at the time of molding. It is preferable to use a resin excellent in oil resistance, weather resistance and strength as a synthetic resin. Examples of such a resin include polyamide 46 (PA46) and polyamide 66 (PA66). In order to further improve the mechanical strength, it is preferable to mix reinforced glass fibers in these resins.

  The guide base 21 may be cast using a light metal such as an aluminum alloy or a magnesium alloy, or may be die-cast.

  The roller shaft 31 is made of SUJ2 or SC material. The roller shaft 31 is heat treated to increase its hardness in order to improve wear resistance. Here, bright quenching is employed as the heat treatment, but induction quenching or carburizing quenching may be performed. Alternatively, carbonitriding may be performed.

  The plurality of rollers 41 are rotatably supported by each of the plurality of roller shafts 31. Here, a roller bearing is employed as the roller 41. The roller bearing 41 includes an outer ring 42, a plurality of rollers 43 incorporated inside the outer ring 42, and a cage 44 that holds the rollers 43.

  The outer ring 42 is a shell shape obtained by drawing a metal plate such as SPC or SCM, and the hardness is increased by heat treatment. At both ends of the shell-shaped outer ring 42, inward flanges 45 that prevent the retainer 44 from being pulled out are formed. The inward flange 45 is bent after the cage 44 for holding the rollers 43 is assembled in order to facilitate the assembly of the roller bearing 41.

  The roller bearing may be a needle roller bearing or a cylindrical roller bearing. The roller bearing may be of a full roller type without a cage.

  The chain transmission shown in the embodiment has the above-described structure, and in a torque transmission state in which the rotation of the crankshaft 1 is transmitted to the camshaft 3 by the movement of the timing chain 5 spanned between the driving sprocket 2 and the driven sprocket 4. When the tension of the timing chain 5 changes due to a change in load, the chain guide 11 operates to absorb the tension change. For this reason, the timing chain 5 is always maintained in a predetermined tension state.

When transmitting torque for transmitting the rotation of the crankshaft 1 to the camshaft 3, the roller 41 composed of the roller bearings of the swingable chain guide A ₁ and the fixed chain guide A ₂ rotates by contact with the timing chain 5. The timing chain 5 is guided to roll.

  Thus, since the timing chain 5 is guided by the rolling of the roller 41, wear at the guide portion is small. In addition, the movement resistance of the timing chain 5 is small, the timing chain 5 moves smoothly, and torque is transmitted without loss.

  In the chain transmission device, as in the prior art, the oil flows out from the oil outlet of the lubricating device provided in the engine and is scattered, or the oil supplied to the chain tensioner 11 is discharged from the tip of the tensioner. Oil is scattered and the roller bearing 41 is oil-lubricated with the scattered oil. In this case, the scattered oil adheres to the outer surface of the outer ring 42 of the roller bearing 41, the outer surface of the roller shaft 31, and the outer surface of the side plate portion 22 of the guide base 21.

  At this time, the oil guide hole 26 is formed in the wall surface of the tapered groove portion 25 a of the shaft engaging portion 25 formed in the side plate portion 22 and penetrates the outer surface of the side plate portion 22. The oil adhering to the surface flows into the tapered groove 25a from the oil guide hole 26, and further flows into the roller bearing 41 along with the adhering oil already adhering to the roller shaft 31 along the outer diameter surface of the roller shaft 31. Then, the roller bearing 41 is oil-lubricated.

  Thus, since the oil adhering to the outer surface of the side plate portion 22 is taken into the roller bearing 41 from the oil guide hole 26, the contact between the roller rolling surfaces 32 and 43 formed on the outer diameter surface of the roller shaft 31 is achieved. And the contact portion of the raceway surface 43 formed on the inner periphery of the outer ring 42 is effectively oil-lubricated.

  Here, foreign matter may be mixed in the oil that lubricates the roller bearing 41, and if the foreign matter enters the roller bearing 41, the roller bearing 41 may be damaged by the biting of the foreign matter. Therefore, as shown in FIG. 9, when a roller bearing 41 with a seal in which a seal 46 for preventing entry of foreign matter is incorporated in the open end portion of the outer ring 42 is used, damage to the roller bearing 41 is prevented and deterioration in durability is suppressed. can do.

  In the use of the roller bearing 41 with the seal as described above, if the inner diameter portion of the seal 46 is in elastic contact with the outer diameter surface of the roller shaft 31, it becomes impossible to take lubricating oil into the outer ring 42. The inner diameter of the seal 46 is made slightly larger than the outer diameter of the roller shaft 31 so that a gap 47 is formed between the inner diameter surface of 46 and the roller rolling surface of the roller shaft 31.

  3 and 4, the oil guide hole 26 is provided in the wall surface of the tapered groove portion 25a. However, as shown in FIGS. 5 and 6, the roller 43 and the roller shaft 31 in the load region T receiving the radial load of the roller bearing 41 are used. The oil guide hole 26 may be provided on the extended line of the contact portion with the roller rolling surface 32 formed on the outer periphery of the roller. In this case, the oil flowing into the oil guide hole 26 smoothly flows into the roller bearing 41, and the oil can be effectively taken into the roller bearing 41.

  3 and 4, the shaft support portion 25b is formed as the shaft engaging portion 25 for supporting the shaft end portion of the roller shaft 31 so as to communicate with the narrow end of the taper groove portion 25a, and at the narrow end of the taper groove portion 25a. Although the roller shaft 31 is shown as being prevented from being removed, the shaft engaging portion 25 is not limited to this.

  7 and 8 show another example of the shaft engaging portion 25. The shaft engaging portion 25 in this example includes a tapered groove portion 25a and a shaft support portion 25b communicating with the tapered groove portion 25a, like the shaft engaging portion 25 shown in FIG. 3 and FIG. A flat surface 27 that engages with a flat surface 33 formed on the outer periphery of the shaft end of the roller shaft 31 to prevent the roller shaft 31 from rotating is provided at a position opposite to the inner periphery of the roller shaft 31, and the end of the flat surface 27 is tapered. Both side surfaces of the groove portion 25a are continuously provided, and both side surfaces are gently inclined outward.

  Further, an oil guide hole 26 having an inner peripheral side facing the taper groove 25a is provided on the wall surface of the shaft support portion 25b facing the shaft end surface of the roller shaft 31, and the oil guide hole 26 can be elastically deformed to the inner peripheral side of the oil guide hole 26. A stop protrusion 28 is provided, and the retaining protrusion 28 is engaged with the upper outer peripheral portion of the shaft end of the roller shaft 31 to prevent the roller shaft 31 from being removed. An inclined guide is formed on the inner surface of the retaining protrusion 28. A surface 29 is provided.

  In the shaft engaging portion 25 having the above-described configuration, when the roller shaft 31 is inserted into the shaft engaging portion 25, the shaft end surface of the roller shaft 31 presses the guide surface 29 of the retaining projection 28. The retaining projection 28 is elastically deformed smoothly in a direction that allows passage of the shaft end of the roller shaft 31. Further, when the shaft end portion of the roller shaft 31 passes through the position of the retaining projection 28 and is supported by the shaft support portion 25b, the retaining projection 28 recovers its shape by its own restoring elasticity, and the roller shaft 31 Since it engages with the outer periphery of the shaft end, the roller shaft 31 can be assembled smoothly.

  Here, when the guide base 21 is formed of a synthetic resin, the roller shaft 31 is inserted into the roller bearing 41, and in the assembled state, the shaft end portion of the roller shaft 31 is insert-molded at the same time as the side plate portion 22 is molded. The unit 22 may be integrated. In this case, the shaft engaging portion 25 is provided around the roller shaft 31.

A ₁ Chain guide A ₂ Chain guide 2 Drive sprocket 4 Driven sprocket 5 Timing chain (chain)
21 Guide base 22 Side plate part 25 Shaft engaging part 25a Taper groove part 25b Shaft support part (closed end part)
26 oil guide hole 27 flat surface 28 retaining projection 31 roller shaft 32 roller rolling surface 33 flat surface 41 roller (roller bearing)
42 Outer ring 43 Roller 46 Seal 47 Clearance

Claims (1)

A guide base having a pair of opposed side plate portions that are disposed on a part of the outer periphery of the timing chain and extend in the moving direction of the timing chain, and a shaft end portion on a shaft engaging portion provided at a position opposite to the side plate portion. Supported by a plurality of roller shafts provided at intervals in the length direction of the side plate portion, and a plurality of chain guide rollers rotatably supported on each of the plurality of roller shafts, In the chain guide wherein the roller is a roller bearing having an outer ring and a plurality of rollers incorporated inside the outer ring,
An oil guide hole penetrating the inner surface and the outer surface of the side plate portion is provided on or around the shaft engaging portion in the side plate portion,
A chain guide in which the oil guide hole is disposed on an extended line of a contact portion between a roller in a load region that receives a radial load of the roller bearing and a roller rolling surface formed on the outer periphery of the roller shaft .

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