JP2017057946A - Chain guide and chain transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the co-rotation of a roller shaft in a state which is advantageous in terms of cost.SOLUTION: A plurality of roller shaft support parts 24 are arranged at a pair of opposing side plates 21 of a guide base 20 which are oppositely arranged at one side of a torque transmission timing chain 5 in a circular arrangement, and shaft ends of roller shafts 30 are supported by the roller shaft support parts 24. A plurality of chain guide rollers 40 are rotatably supported by a plurality of the roller shafts 30. Face engagement parts 31 are formed at only external peripheries of other ends of the roller shafts 30 with one-end side external peripheries of the roller shafts 30 at an engine block side as circular shapes in cross sections, and the face engagement part 31 are engaged with face engagement parts 27 which are formed at the roller shaft support parts 24, thus whirl-stopping the roller shafts 30.SELECTED DRAWING: Figure 5

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.

  In addition, 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 cross There's a problem.

  In order to solve such a problem, in the chain guide described in Patent Document 1, the timing chain is rolled and guided by a roller to reduce movement resistance.

  However, in the chain guide described in Patent Document 1, since the roller shaft that rotatably supports the roller is inserted and assembled from the side of the side wall member that constitutes the chain guide, the assembly work efficiency is improved. There is a problem of being bad.

  In order to improve the efficiency of the assembly work, in the chain guides described in Patent Documents 2 and 3, the roller shaft support portion of the side plate constituting the chain guide opens at the side edge of the side plate facing the timing chain. A tapered groove-shaped insertion recess and an arc-shaped support recess that communicates with the narrow end of the insertion recess are provided. The shaft end of the roller shaft is inserted into the support recess from the insertion recess, and the roller shaft is connected to the timing chain. It is built from the side.

  By the way, in the chain guides described in Patent Documents 2 and 3, since the support recess for supporting the shaft end portion of the roller shaft is circular, the roller shaft cannot be prevented from rotating. The shaft may be rotated around. Here, when the roller shaft is rotated, the inner periphery of the support concave portion of the side plate made of resin is worn by contact with the roller shaft, and the support of the roller becomes unstable, and the timing chain may be rolled and guided. become unable.

  In order to prevent the wear, the chain guide described in Patent Document 4 is formed on the side plate by providing a surface engaging portion made of a flat surface or an uneven surface on the outer periphery of the shaft end portion of the roller shaft that supports the roller. A surface engaging portion that engages with the surface engaging portion of the roller shaft is provided on the inner periphery of the supporting recess, and the roller shaft is prevented from rotating by the engagement of the surface engaging portion of the roller shaft and the surface engaging portion of the supporting recess. doing.

JP-A-9-236157 International Publication No. 2010/090139 JP 2012-189200 A JP 2013-253649 A

  By the way, in the chain guide described in Patent Document 4, since the surface engaging portions are provided at both end portions of the roller shaft, the processing cost is high, and the insertion groove-shaped insertion recess that communicates with the support recess is also provided. In order to prevent the roller shaft from being pulled out at the narrow end portion, when the roller shaft is assembled, it is necessary to force the narrow end portion (constriction portion) of the insertion recess to pass through, and the constriction portion may be worn and damaged.

  Since the chain guide is cantilevered with one end supported by the engine block, when a load is applied from the timing chain, the chain guide tilts in the width direction, and the roller moves at one end on the engine block side. Only contact with the timing chain and the load concentrates on the contact part. At this time, if the surface engaging portion formed at the shaft end portion of the roller shaft has a two-surface width in which a flat surface is formed at a position opposed to the outer periphery, the area of the arc surface between the two surface widths is small. Therefore, the surface pressure at the support surface that supports the arc surface of the support recess is increased, and the support surface may be damaged.

  An object of the present invention is to prevent rotation of a roller shaft in a cost advantageous state.

  In order to solve the above-mentioned problems, in the chain guide according to the present invention, a resin guide base having a pair of opposed side plate portions that are arranged on a part of the outer periphery of the timing chain and extend long in the moving direction of the timing chain And a plurality of metal roller shafts having shaft end portions supported by a pair of opposed roller shaft support portions formed on the side plate portion of the guide base and spaced 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, wherein the outer periphery of one end of the roller shaft is circular and the outer periphery of the other end of the roller shaft Is provided with a surface engaging portion, and the roller shaft supporting portion that supports the other end portion of the roller shaft has a surface engagement with the surface engaging portion of the roller shaft so as to prevent the roller shaft from rotating. Department adopts a configuration provided.

  In the chain transmission according to the present invention, the timing chain is spanned between the drive sprocket and the driven sprocket, and can swing on one side of the slack side chain of the timing chain to guide the movement of the timing chain. In a chain transmission in which a chain guide is provided, the adjusting force of the chain tensioner is loaded on the swing side end of the chain guide, and the swing side end is pressed against the timing chain. The chain guide according to the invention is adopted.

  In the chain guide according to the present invention, as described above, the outer periphery of the one end portion on the engine block side in the assembled state of the chain guide of the roller shaft has a circular cross section, and the surface engaging portion is provided on the outer periphery of the other end portion of the roller shaft. The surface engaging portion of the roller shaft and the surface of the roller shaft supporting portion are provided by providing a surface engaging portion that engages with the surface engaging portion of the roller shaft on the roller shaft supporting portion that supports the other end portion of the roller shaft. The roller shaft can be prevented from rotating by the engagement of the engaging portion. At this time, since the surface engaging portion is provided only at the other end portion of the roller shaft, the processing of the roller shaft is easier as compared with the case where the surface engaging portion is provided at both end portions.

  Since the chain guide is used in a cantilevered manner in which one end is supported by the engine block, when the load inclines in the width direction due to the load from the timing chain, the roller has one end on the engine block side. The load concentrates on the roller shaft, and the concentrated load acts on one end of the roller shaft.

  Therefore, it is preferable that one end of the roller shaft having a circular cross section is on the engine block side when the chain guide is assembled to the engine block.

  As described above, if one end of the roller shaft having a circular cross section is on the engine block side, the chain guide is inclined in the width direction due to the load applied from the timing chain, and a concentrated load is applied to one end of the roller shaft. However, since the outer peripheral cross-sectional shape of one end of the roller shaft is circular and the outer peripheral cylindrical surface of the one end is supported by the roller shaft support portion, the shaft end portion where the surface engaging portion is formed is the roller shaft. Compared with the case of supporting by the support portion, the pressure receiving area at the roller shaft support portion is large and the surface pressure is conversely small, so that damage to the roller shaft support portion can be prevented.

  Here, each of the pair of opposed roller shaft support portions communicates with a tapered groove-shaped insertion concave 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 a narrow end of the insertion concave portion. A support recess for supporting the shaft end of the roller shaft, the support recess is shaped along the outer periphery of the shaft end of the roller shaft, and an L-shaped stealing portion is formed around the narrow end of the insertion recess. Further, it is preferable to provide an elastically deformable retaining piece for engaging the outer periphery of the shaft end portion of the roller shaft and retaining the roller shaft from the stealing portion toward the insertion recess.

  As described above, when the retaining piece portion that can be elastically deformed by forming the stealing portion is provided, when the shaft end portion of the roller shaft is fitted from the insertion recess to the support recess, the retaining piece portion is placed on the stealing portion side. Since it is elastically deformed to allow passage of the shaft end portion of the roller shaft, wear of the constricted portion of the insertion recess can be prevented.

  Further, when the shaft end portion of the roller shaft is supported by the supporting recess, the retaining piece portion engages with the outer periphery of the shaft end portion of the roller shaft, so that the roller shaft can be reliably retained.

  Here, the surface engaging portion of the roller shaft may be composed of a flat surface formed on one side of the outer periphery, or may be composed of a pair of flat surfaces formed on both sides of the outer periphery. The surface engaging portion of the roller shaft support portion has a shape corresponding to the surface shape of the surface engaging portion of the roller shaft, and is a detent for the roller shaft.

  In the present invention, as described above, the surface engaging portion is provided at the other end portion of the roller shaft, and the surface engaging portion is engaged with the surface engaging portion of the roller shaft supporting portion that supports the other end portion of the roller shaft. Since the rotation of the roller shaft is prevented, the roller shaft can be reliably prevented from rotating in contact with the rotation of the roller.

  In addition, when the surface engaging portions are provided at both ends of the roller shaft, it is necessary to provide the surface engaging portion at one end and then the surface engaging portion at the other end. Since it is necessary to process the surface engaging portion to be processed in the same direction as the previously processed surface engaging portion, the processing is very troublesome. Since it is formed only at the other end, it is possible to reduce the processing cost and to reduce the processing cost because it is not necessary to match the orientation of the surface engaging portion. .

Schematic showing the embodiment of the chain transmission according to the present invention Side view of the chain guide shown on the left side of FIG. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. Sectional view along line VV in FIG. Sectional view along line VI-VI in FIG. Sectional drawing along the VII-VII line of FIG. Sectional view along line VIII-VIII in FIG. Sectional view along line IX-IX in FIG. Sectional drawing which shows the other example of a surface engaging part Sectional view along line XI-XI in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a chain transmission device for driving a camshaft provided on one side of an engine block B shown in FIG. 2, and a shaft end of a drive sprocket 2 and a camshaft 3 attached to a shaft end portion of a crankshaft 1. A timing chain 5 is spanned between driven sprockets 4 attached to the section.

  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 the figure, the portion moving upward is a slack side chain 5a, and the portion moving downward is a tension side chain 5b. 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 B (see FIG. 2), and can swing around the fulcrum shaft 10. Thus, the adjustment force of the chain tensioner 11 is applied to the lower swinging side end portion and 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. Guide the move.

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 6, the chain guide A ₁ includes a guide base 20 that extends 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 20. 30 and a plurality of chain guide rollers 40 rotatably supported on each of the plurality of roller shafts 30.

  The guide base 20 has a configuration in which a plurality of plate-like interval holding members 22 are formed at intervals in the length direction between a pair of opposed side plate portions 21. The pair of side plate portions 21 has a bow shape, and an insertion hole 23 into which the fulcrum shaft 10 is inserted is formed at the upper end portion thereof.

  A plurality of roller shaft support portions 24 that support the shaft end portion of the roller shaft 30 are formed on the opposing inner surfaces of the pair of side plate portions 21 at intervals in the length direction of the side plate portion 21.

  The roller shaft support portion 24 is oriented in the width direction of the side plate portion 21 from the outer surface portion facing the timing chain 5 of the side plate portion 21, and has a tapered groove-shaped insertion recess 24a in which the opening end of the outer surface portion is widened. It consists of a support recess 24b as a closed end communicating with the narrow end of the insertion recess 24a. The roller shaft 30 is fitted into the support recess 24b from the insertion recess 24a and supported by the support recess 24b.

  Here, the roller shaft 30 is formed in a columnar shape, the cross-sectional shape of one end is circular, and a surface engaging portion 31 composed of a pair of flat surfaces is formed at a position opposite to the outer periphery of the other end. The roller shaft 30 is supported by a roller shaft support portion 24 formed on one side plate portion 21 on the engine block B side of the guide base 20 with a circular cross-sectional shape, and a surface engaging portion 31 is formed. The end portion is incorporated so as to be supported by a roller shaft support portion 24 formed on the other side plate portion 21 of the guide base 20.

  As shown in FIGS. 5 to 7, the support recess 24 b of the roller shaft support portion 24 formed on the one side plate portion 21 on the engine block B side of the guide base 20 has a circular shape along the outer periphery of one end portion of the roller shaft 30. ing.

  Further, an L-shaped stealing portion 25 that opens on both sides of the support recess 24b is formed around the narrow portion of the insertion recess 24a of the roller shaft support portion 24, and a roller is formed from the stealing portion 25 toward the insertion recess 24a. An elastically deformable retaining piece portion 26 that engages with the outer periphery of one end portion of the shaft 30 to retain the roller shaft 30 is provided.

  On the other hand, the support recess 24a of the roller shaft support portion 24 formed on the other side plate portion 21 away from the engine block B of the guide base 20 has a pair of flat surfaces as shown in FIGS. The surface engaging portion 27 is formed, and the surface engaging portion 27 engages with the surface engaging portion 31 of the roller shaft 30 to prevent the roller shaft 30 from rotating.

  Further, an L-shaped stealing portion 28 that opens on both sides of the support concave portion 24b is formed around the narrow portion of the insertion concave portion 24a of the roller shaft support portion 24. An elastically deformable retaining piece portion 29 that engages with the outer periphery of the other end portion of the shaft 30 to retain the roller shaft 30 is provided.

  As shown in FIG. 3, the plurality of roller shaft support portions 24 have an arcuate arrangement in which a line connecting the centers of the support recesses 24b draws a convex arcuate line, but has a curved arrangement. It may be.

  The guide base 20 having the above configuration is a synthetic resin molded product. 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 roller shaft 30 is made of SUJ2 or SC material. The roller shaft 30 is heat treated to increase the 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 40 are rotatably supported by each of the plurality of roller shafts 30. Here, a roller bearing is employed as the roller 40. As shown in FIG. 5, the roller bearing 40 includes an outer ring 41, a plurality of rollers 42 incorporated inside the outer ring 41, and a cage 43 that holds the rollers 42.

  The outer ring 41 has 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 41, inward flanges 44 that prevent the retainer 43 from being removed are formed. The inward flange 44 is bent after the cage 43 that holds the rollers 42 is assembled in order to facilitate the assembly of the roller bearing 40.

  The roller bearing 40 may be a needle roller bearing or a cylindrical roller bearing. The roller bearing 40 may be of a full roller type without a cage.

  The chain transmission shown in the embodiment has the above-described structure, and 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 shown in FIG. In the torque transmission state, when the tension of the timing chain 5 changes due to load fluctuations, the chain tensioner 11 operates to absorb the tension change. For this reason, the timing chain 5 is always maintained in a predetermined tension state.

During torque transmission for transmitting the rotation of the crank shaft 1 to the camshaft 3, the roller 40 consisting of the respective roller bearing pivotable chain guide A ₁ and the fixed chain guide A ₂ is rotated 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 40, 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 addition, each of the plurality of rollers 40 of the swingable chain guide A ₁ and the fixed chain guide A ₂ is rotated by contact with the timing chain 5 as described above. Turning torque is applied.

  At this time, as shown in FIGS. 5 and 8, a surface engaging portion 31 is formed at the other end of the roller shaft 30, and the surface engaging portion 31 is an inner periphery of the support recessed portion 24 b of the roller shaft supporting portion 24. Since the engaging torque applied to the roller shaft 30 is received by the surface engaging portion 27, the roller shaft 30 does not rotate.

  Therefore, there is no inconvenience that the support recess 24b of the roller shaft support portion 24 is worn by contact with the roller shaft 30, and the guide base 20 is not damaged.

  Further, since the surface engaging portion 31 that prevents the roller shaft 30 from rotating is provided only at the other end portion of the roller shaft 30, the roller engaging portion 30 of the roller shaft 30 is compared with the case where the surface engaging portion 31 is provided at both end portions. Processing can be facilitated.

  As shown in FIGS. 5 and 8, when the surface engaging portion 31 is a flat surface parallel to the insertion direction of the roller shaft 30 with respect to the roller shaft support portion 24, the pressing force from the timing chain 5 of the support recess 24b is the surface. The rotational torque applied to the roller shaft 30 from the roller 40 is supported by the contact portion on the bottom surface of the arc of the support recess 24b formed between the engagement portions 31, and the surface engagement between the surface engagement portion 31 and the support recess 24b. Since it is supported by the engaging surface of the joint portion 27, two load forces applied to the roller shaft 30 can be distributed and supported, and an effect can be obtained in preventing damage to the support recess 24b.

Here, as shown in FIG. 2, the chain guide A ₁ is a cantilever support whose one end is supported by a fulcrum shaft 10 projecting from the engine block B, and the support portion includes the chain guide A ₁ . Since there is a gap that enables swinging, the chain guide A ₁ is inclined in the width direction by the load applied from the timing chain 5. That is, in the state shown in FIG. 5, the chain guide A ₁ is occurs direction tilt side plate portion 21 of the left side of the figure moves downward, the engine block B in the roller 40 by the tilting of the chain guide A ₁ The load concentrates on one end portion (point P shown in FIG. 5), and the concentrated load acts on one end portion of the roller shaft 30.

  At this time, the cross-sectional shape of the outer periphery of one end portion of the roller shaft 30 is circular, and the outer peripheral cylindrical surface of the one end portion is supported by the support recess 24b of the roller shaft support portion 24, so that a surface engaging portion is formed. Compared with the case where the shaft end is supported, the pressure receiving area in the support recess 24b is large, and conversely, the surface pressure is reduced, and the support recess 24b is not damaged.

  In the embodiment, as shown in FIGS. 6 and 8, L-shaped stealing portions 25 and 28 are formed around the narrow end portion of the insertion concave portion 24a in the roller shaft support portion 24, and the stealing portions 25 and 28 are formed. Since the retaining pieces 26 and 29 that can be elastically deformed are provided on the insertion recess 24a side from the insertion recess 24a, the retaining piece 26 is attached when the shaft end of the roller shaft 30 is fitted from the insertion recess 24a to the support recess 24b. , 29 are elastically deformed toward the stealing portions 25, 28 by contact with the roller shaft 30 to allow passage of the shaft end portion of the roller shaft 30. For this reason, the narrow portion of the insertion recess 24 a is not worn by contact with the roller shaft 30.

  When the shaft end portion of the roller shaft 30 passes through the narrow portion of the insertion recess 24a and is supported by the support recess 24b, the retaining pieces 26 and 29 are restored in shape by their own restoring elasticity, and the roller shaft 30 Engage with the outer periphery of the shaft end. For this reason, the roller shaft 30 can be reliably secured.

  In FIG. 8, the surface engaging part 31 which consists of a pair of flat surfaces was formed in the outer periphery of the other end part of the roller shaft 30, However, The surface engaging part 31 is not limited to this, For example, as shown to FIG. 10 and FIG. Alternatively, it may be composed of a single flat surface 31 formed on one side of the outer periphery of the roller shaft 30. In this case, the surface engaging portion 27 of the roller shaft support portion 24 has a shape corresponding to the surface shape of the surface engaging portion 31 of the roller shaft 30 to prevent the roller shaft 30 from rotating.

A ₁ Chain guide 2 Drive sprocket 4 Driven sprocket 5 Timing chain (chain)
11 Chain tensioner 20 Guide base 21 Side plate portion 24 Roller shaft support portion 24a Insertion recess portion 24b Support recess portion 25 Stealing portion 26 Retaining piece portion 27 Surface engaging portion 28 Stealing portion 29 Retaining piece portion 30 Roller shaft 31 Surface engaging portion 40 Roller (roller bearing)

Claims (6)

A resin-made guide base disposed on a part of the outer periphery of the timing chain and extending long in the moving direction of the timing chain, and a pair of opposed roller shafts formed on the side plate of the guide base A plurality of metal roller shafts that are supported by the shaft end portion and spaced in the length direction of the side plate portion, and a chain guide that is rotatably supported by each of the plurality of roller shafts In a chain guide consisting of multiple rollers for
The outer periphery of one end of the roller shaft has a circular cross section, a surface engaging portion is provided on the outer periphery of the other end of the roller shaft, and the roller shaft support portion that supports the other end of the roller shaft includes the roller A chain guide, characterized in that a surface engaging portion is provided that is surface-engaged with a surface engaging portion of the shaft to prevent the roller shaft from rotating.   2. The chain guide according to claim 1, wherein one end of the roller shaft having a circular cross section is on the engine block side when the chain guide is assembled to the engine block.   Each of the pair of opposed roller shaft support portions communicates with a tapered groove-shaped insertion concave 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 a narrow end of the insertion concave portion. A support recess for supporting the shaft end, the support recess is shaped along the outer periphery of the shaft end of the roller shaft, and an L-shaped stealing portion is formed around the narrow end of the insertion recess. The chain according to claim 1 or 2, wherein an elastically deformable retaining piece for engaging the outer periphery of the shaft end of the roller shaft and retaining the roller shaft is provided on the insertion recess side from the stealing portion. guide.   The surface engaging portion of the roller shaft is a flat surface formed on one side of the outer periphery, and the surface engaging portion of the roller shaft supporting portion is a flat surface that is surface-engaged with the flat surface of the roller shaft. The chain guide according to any one of claims 1 to 3.   The surface engaging portion of the roller shaft is composed of a pair of flat surfaces formed on both sides of the outer periphery, and the surface engaging portion of the roller shaft supporting portion is surface-engaged with each of the pair of flat surfaces of the roller shaft. The chain guide according to any one of claims 1 to 3, wherein the chain guide is a flat surface. A timing chain is stretched between the drive sprocket and the driven sprocket, and a swingable chain guide for guiding the movement of the timing chain is provided on one side of the slack side chain of the timing chain. In the chain transmission device in which the adjustment force of the chain tensioner is loaded on the side end and the swing side end is pressed against the timing chain,
A chain transmission device, wherein the chain guide is the chain guide according to any one of claims 1 to 5.

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