JP2013185700A - Chain guide, and chain drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a long service life of a chain guide by suppressing wear in a contact portion between a cage and a flange of an outer ring of a roller bearing for guiding a chain thereof.SOLUTION: Each of shaft ends of a plurality of roller shafts 31 is supported by a pair of opposing side plates 22 of a guide base 21, which is disposed to oppose to one side of a timing chain 5 for torque transmission. Each of the plurality of roller shafts 31 rotatably supports a needle roller bearing 41 for guiding a chain. An inward flange 46 disposed at both ends of an outer ring 42 of the needle roller bearing 41, and a cage 43 for retaining a needle roller 45 are configured to have Vickers hardnesses of HV 650 or higher, respectively, that are almost same. Thereby, when the flange 46 contacts the cage 43 and rotates, wear in the contact part can be suppressed.

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.

  In the chain transmission device for driving the camshaft, in which the timing chain is spanned between the drive sprocket attached to the crankshaft and the driven sprocket attached to the camshaft, the chain can swing to one side of the slack side chain of the timing chain. A 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 Patent Document 1, both ends of a plurality of roller shafts arranged in a curved shape are supported by a guide base that extends in the moving direction of the timing chain. A chain guide is proposed in which a roller comprising a roller bearing is rotatably supported by each of the rollers, and the timing chain is supported by the plurality of rollers so as to be movable.

  The above-described chain guide is characterized in that the timing chain is guided by the rolling of the outer ring in the roller bearing, 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 the above-mentioned Patent Document 1, a needle roller bearing in which a needle roller and a retainer for holding the needle roller are incorporated in a shell-shaped outer ring is used as the roller. In this case, the outer ring was damaged early.

  As a result of investigating the cause, the roller bearing used in the chain guide described in Patent Document 1 has its outer ring in rolling contact with the timing chain. However, an uneven load is applied to the outer ring of the roller bearing due to the timing chain flapping. The cage that holds the outer ring is relatively moved in the axial direction due to the load of the offset load, and the end surface of the cage contacts the inner surface of the inward flange formed at the axial end of the outer ring. To do.

  At this time, since the outer ring rotates at a high speed due to contact with the timing chain, the flange portion of the outer ring rotates relative to the end surface of the cage. In the case of a shell-type needle roller bearing, the drawn shell-shaped outer ring is bent at the flange, so the overall hardness is increased by heat treatment, the end is annealed, and the annealed end is bent inward. Molded to form a cage retaining cage.

  For this reason, the collar part of the outer ring is lower in hardness than other parts by annealing, and the end surface of the cage comes into contact with the collar part having the lower hardness and relatively rotates at a high speed. It turns out.

  The inventors of this case focused on the hardness of the outer ring collar and the cage, and thought that it would be possible to improve the durability if the hardness was almost equal, the hardness was equal. It turns out that it is not enough.

  SUMMARY OF THE INVENTION An object of the present invention is to suppress the wear at the outer ring collar portion of a roller bearing used in a chain guide to which an unbalanced load is applied due to the timing chain flapping and the contact portion of the cage, thereby extending the life.

  In order to solve the above-described problem, in the chain guide according to the present invention, a guide base having a side plate portion that is disposed on a part of the outer periphery of the timing chain and extends long in the moving direction of the timing chain, and the guide base Both end portions are supported by the side plate portion, a plurality of roller shafts provided at intervals in the length direction of the side plate portion, and a plurality of chain guides rotatably supported on each of the plurality of roller shafts In a chain guide comprising a roller bearing in which a roller and a cage for holding the roller are incorporated in a flanged outer ring, the roller is an inward flange portion provided at both axial ends of the outer ring. And the structure which made each hardness of the said holder | retainer HV650 or more by Vickers hardness, and was made into the substantially equivalent hardness was employ | adopted.

  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, timing chain flapping can be effectively suppressed.

  Here, as described above, even if the fixed chain guide is provided, it is impossible to completely prevent the timing chain from flickering. When the timing chain fluctuates, an eccentric load is applied to the outer ring of the roller bearing, the cage that holds the outer ring moves relatively in the axial direction, and the end surface of the cage is formed at the axial end of the outer ring. It contacts the inner surface of the facing collar.

  At this time, each of the inward flanges and the cages provided at both ends of the outer ring in the axial direction has a Vickers hardness of HV650 or more, and the hardness of the outer ring flanges and the cage is substantially equal. Therefore, even when the end surface of the cage is relatively rotated in contact with the inner surface of the inward flange formed at the axial end of the outer ring, the contact surface is not worn at an early stage.

  Here, the hardness of the outer ring collar part and the cage being substantially equal means that the difference in hardness is HV50 points or less in terms of Vickers hardness.

  In the chain guide according to the present invention, in the assembled state in which the cage is incorporated in the outer ring, each of the outer ring and the cage is subjected to heat treatment at the same time, so that the outer ring collar portion and the cage are almost easily made to have substantially the same hardness. be able to.

  Further, if the end surface facing the outer ring collar part of the cage is a flat surface parallel to the inner surface of the collar part, the entire cage end surface made of the flat surface can be brought into full contact with the inner surface of the collar part. The surface pressure is reduced, and wear at the contact portion can be more effectively suppressed. In this case, it is preferable that the inner diameter of the collar is smaller than the inner diameter of the end of the cage, so that the entire cage end surface is brought into full contact with the inner surface of the collar.

  As the cage, a welded cage in which a strip-like steel plate having pockets formed by press punching is bent into a cylindrical shape and the butt end surfaces thereof are joined by welding can be employed. In this case, a welded cage in which the weld bulge does not protrude from the end face of the cage is used to prevent the bulge of the weld from contacting the inner surface of the outer ring flange.

  In the present invention, as described above, the hardness of the inward flanges and the cages provided at both ends in the axial direction of the outer ring is set to HV650 or more in terms of Vickers hardness, and the hardness of the outer ring flanges and the cage is substantially equal. By making it equivalent, it is possible to suppress wear at the contact portion between the outer ring collar portion and the cage, and it is possible to extend the life by suppressing the decrease in durability.

Schematic showing the embodiment of the chain transmission according to the present invention Longitudinal sectional view of the chain guide according to the present invention Sectional view along line III-III in FIG. Sectional view along line IV-IV in Fig. 3 Sectional drawing which expands and shows a part of FIG. Sectional view showing a part of the welded cage Side view of FIG. Side view showing part of welded cage Plan view showing a part of the welded cage

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

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

The crankshaft 1 is rotated in the direction indicated by the arrow in FIG. As the rotation of the crank shaft 1, the timing chain 5 moves in the direction indicated by the arrow in the figure, the chain guide A ₁ is provided on one side of the slack side chain 5a of the timing chain 5.

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, only the shape is the same configuration is different. Thus, 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. 1 to 3, 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 in the lengthwise direction between a pair of opposed side plate portions 22, and a roller accommodating space 24 is formed between adjacent interval holding plates 23. Is formed.

Incidentally, the side plate portion 22 of the chain guide A ₁ is arcuate, whereas, although the side plate portion 22 of the chain guide A ₂ are set to ribbon-shaped shape are different, the chain guide A ₂ is the chain guide A ₁ Similarly, a bow shape may be used.

  The guide base 21 configured as described above is a synthetic resin molded product, but may be cast using a light metal such as an aluminum alloy or a magnesium alloy, or may be die cast molded.

  Each of the plurality of roller shafts 31 is incorporated into each of the roller accommodating spaces 24, and both ends thereof are supported by the pair of side plate portions 22, and lines connecting the respective shaft centers. Is an arcuate arrangement that draws a convex arcuate line, but may be a curvilinear arrangement.

  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. As the heat treatment, bright quenching, induction quenching, carburizing quenching, or carbonitriding quenching can be employed.

  The plurality of rollers 41 are rotatably supported by each of the plurality of roller shafts 31. As shown in FIGS. 3 to 5, the roller 41 is a needle roller bearing. This needle roller bearing 41 has a configuration in which a retainer 43 is incorporated in an outer ring 42 and needle rollers 45 are incorporated in each of a plurality of pockets 44 formed at intervals in the circumferential direction of the retainer 43. Has been.

  The outer ring 42 is made of a low carbon steel such as SCM, is formed by drawing and has a shell shape, and inward flange portions 46 are formed at both ends in the axial direction. The outer ring 42 is heat-treated after the flange portion 46 is bent, and has a Vickers hardness of HV650 or higher.

  Here, carburizing quenching or carbonitriding quenching is adopted as the heat treatment.

  Each of the column portions 47 formed between the adjacent pockets 44 of the plurality of pockets 44 formed in the retainer 43 and arranged in the circumferential direction is an inner column portion disposed inside the pitch circle diameter of the needle rollers 45. 47a, an inclined column portion 47b that is connected to both axial ends of the inner column portion 47a, and an axial end portion of the inclined column portion 47b that is provided outside the pitch circle diameter of the needle rollers 45. It is formed by the outer pillar part 47c arrange | positioned, and is made into V shape.

  The cage 43 is formed of a low carbon steel plate such as SCM or SPC. The cage 43 is heat-treated together with the outer ring 42 in a state assembled in the outer ring 42, and the hardness thereof is set to HV650 or more in terms of Vickers hardness. The retainer 43 is heat-treated at the same time in a state of being incorporated in the outer ring 42 and has a hardness substantially equal to that of the outer ring 42.

As shown in FIG. 5, the inner diameter d ₁ of the flange portion 46 of the outer ring 42 is smaller than the end inner diameter d ₂ of the retainer 43, and the retainer 43 is prevented from being removed by the flange portion 46. An end surface 43 a of the retainer 43 facing the portion 46 is a flat surface parallel to the inner surface 46 a of the flange portion 46.

  Instead of the needle roller bearing 41, a cylindrical roller bearing may be adopted.

  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 load fluctuations, the chain tensioner 11 prevents looseness and fluttering.

During torque transmission for transmitting the rotation of the crank shaft 1 to the camshaft 3, the outer race 42 of each needle roller bearing 41 can oscillate chain guide A ₁ and the fixed chain guide A ₂ is a timing chain 5 to fast moving The timing chain 5 is guided to roll by the outer ring 42.

  Thus, since the timing chain 5 is guided by the rolling of the outer ring 42 of the needle roller bearing 41, the movement resistance is small, the timing chain 5 moves smoothly, and torque is transmitted without loss.

In chain transmission apparatus shown in FIG. 1, since the provided chain guide A ₂ fixed to the other side of the tight side chains 5b of the timing chain 5, to suppress flapping of the timing chain 5 in the chain guide A ₂ Although it is possible, it cannot completely prevent fluttering.

Here, if the timing chain A ₂ flutters, an eccentric load is applied to the outer ring 42 of the roller bearing 41, and the cage 43 that holds the outer ring 42, 45 moves relatively in the axial direction, and the end face 43 a of the cage 43. Comes into contact with the inner surface 46a of the flange 46 of the outer ring 42 and rotates relative to the contact portion. When the hardness difference between the contact portions is large or the hardness is low, wear occurs at the contact portion.

  However, in the embodiment, the flange portion 46 and the retainer 43 of the outer ring 42 are set to HV650 or higher in terms of Vickers hardness, and the hardness of the outer ring 42 and the retainer 43 is substantially equal. Even if the end surface 43a of the vessel 43 rotates relative to the inner surface 46a of the flange 46 of the outer ring 42, the contact surface does not wear out at an early stage.

  Here, when the end surface 43a of the retainer 43 comes into contact with the inner surface 46a of the flange 46 of the outer ring 42, the end surface 43a of the retainer 43 is a flat surface, and the entire end surface 43a composed of the flat surface is the flange of the outer ring 42. It contacts the inner surface 46a of the portion 46. For this reason, the surface pressure is low, and wear at the contact portion is effectively prevented.

  Here, the cage 43 is formed by cutting, formed by pressing, or by bending a strip-shaped steel plate having pockets 44 formed by press punching into a cylindrical shape and welding the butt end surface thereof. What was joined can be adopted.

  In the use of the welded cage 43 in which the strip steel plate is bent into a cylindrical shape and the butt end surfaces thereof are joined by welding, the raised portion of the welded portion is not disposed so as to protrude outward from the end surface of the cage 43. 6 and 7, welding is performed along the butt end surface from the outer diameter side of the cage 43, or welding is performed along the butt end surface from the inner diameter side of the cage 43 as illustrated in FIG. 8. Further, welding is performed from both the outer diameter side and the inner diameter side of the cage 43, and further, as shown in FIG. 9, a V-shaped groove 50 is formed on the end surface of the cage 43, and the groove 50 is welded. Make it. Reference numeral 51 shown in FIGS. 6 to 9 denotes a welded portion.

A ₁ chain guide A ₂ chain guide 2 drive sprocket 4 driven sprocket 5 timing chain 21 guide base 22 side plate portion 31 roller shaft 41 needle roller bearing (roller)
42 outer ring 43 cage 43a end face 45 needle roller
46 Inner surface 46a

Claims (7)

A guide base having a side plate portion that is arranged on a part of the outer periphery of the timing chain and extends long in the moving direction of the timing chain, and both end portions are supported by the side plate portion of the guide base, in the length direction of the side plate portion A plurality of roller shafts provided at intervals, and a plurality of chain guide rollers rotatably supported by each of the plurality of roller shafts. In chain guides consisting of roller bearings with cages that hold the rollers,
Chain guides characterized in that the inward flanges provided at both ends of the outer ring in the axial direction and the cage have a Vickers hardness of HV650 or higher and substantially the same hardness. .   The chain guide according to claim 1, wherein the outer ring and the cage are heat treated products, and the heat treatment is performed by simultaneous heat treatment in a state where the cage is incorporated in the outer ring.   The chain guide according to claim 1 or 2, wherein an end surface of the retainer facing the flange is a flat surface parallel to the inner surface of the flange.   The chain guide according to any one of claims 1 to 3, wherein an inner diameter of a flange portion of the outer ring is smaller than an inner diameter of an end portion of the cage.   The said cage | basket consists of a welding cage | basket by which the butt end of both ends was welded by bending in the shape of a cylinder, and the bulging part of the welding part did not protrude from a cage | basket end surface. Chain guide according to any one of the items. A timing chain is placed between the drive sprocket and the driven sprocket, and a swingable chain guide is provided on one side of the slack side chain of the timing chain to guide the movement of the timing chain. In the chain transmission device, the adjustment force of the chain tensioner is applied to the part, and the swing side end is pressed against the timing chain.
A chain transmission device, wherein the chain guide comprises the chain guide according to any one of claims 1 to 5.   6. A chain guide for guiding the movement of the timing chain is provided on one side of the tension chain of the timing chain so that the chain guide is fixed, and the chain guide is a chain guide according to any one of claims 1 to 5. The chain transmission device according to claim 6.

Images