guide shoe

Abstract

Chain guide with a guide shoe (100), and a chain (200) having link plates (201), held under tension by a tensioner (T), which runs between sprockets (S) of the chain guide and is guided slidably by the guide shoe (100). the guide shoe (100) has: a sliding surface (111) which guides the link plates (201) of the running chain (200) in a sliding manner; and a plurality of guide projections (112) provided on the sliding surface (111), each of the guide projections (112) having a single vertex projecting in a vertical direction from the sliding surface (111), wherein each front surface of the guide projections (112) is designed such that it has a convexly curved surface at least from a part of the same on a front side to an upper part of the same in a chain travel direction, wherein the guide projections (112) on the sliding surface (111) are provided at the same distance from each other, wherein the plurality of guide projections (112) has guide projections which are arranged at different positions in the chain direction, wherein a distance (ta) in a shoe-width direction between the upper parts of the plurality of guide projections (112) in a region in which the link plate (201) of the chain (200) slides, seen in the chain running direction, is a plate thickness (tb) of the link plate (201) of the chain (200) or less, and where a distance (ta) in the chain running direction between the upper parts of the plurality of guide projections (112) seen in a shoe width direction is a distance (tc) between pin pitches of the chain (200) or less.

Description

BACKGROUND OF THE INVENTION 1. Subject area of ​​the invention

[0001] The present invention relates to a guide shoe having a sliding surface that guides a running chain in a sliding manner. 2. Description of the state of the art

[0002] A well-known chain guide is a type that is installed in a timing system in the engine compartment of a car, guiding a chain that runs between sprockets, sliding it and maintaining an appropriate chain tension.

[0003] For example, Japanese patent application JP H08-303 541 A describes a guide shoe (chain guide shoe 10) in which tiny irregularities caused by a creep process and grooves 20 are provided along substantially the entire region in the longitudinal direction of a sliding surface (contact surface 12A) on the sliding surface (contact surface 12A) on which a chain (time control chain 15) comes into contact and slides.

[0004] When a lubricant (oil) is applied to the sliding surface (contact surface 12A) of the guide shoe (chain guide 10), it is held in sufficient quantity by the concave parts formed by the sliding process and by the concave parts of the grooves 20. Therefore, friction generated when the chain (timing chain 15) slides on the sliding surface (contact surface 12A) can be sufficiently suppressed.

[0005] Furthermore, the Japanese patent application JP 2015-218 756 A describes a guide shoe (chain guide 10) in which a sliding surface (guide grooves 11), on which a chain 20 formed by coupling link plates 21 comes into contact and slides, is designed as wave-shaped guide grooves 11 with semicircular convex parts 12 and concave parts 13, each having the same alternating continuous curvature, and in which the radius of curvature of the convex parts 12 and the concave parts 13 is designed such that it is smaller than a radius of curvature of the contact part between the link plates 21 and the sliding surface (guide grooves 11).

[0006] When applied to the corrugated convex parts 12 and concave parts 13 of the guide shoe (chain guide 10), a lubricant (oil) collects in sufficient quantity on the concave parts 13 to lubricate the sliding surface (guide grooves 11). Consequently, the frictional resistance generated between the chain 20 and the chain shoe (chain guide 10) can be reduced.

[0007] Furthermore, the radius of curvature of the convex parts 12 and the concave parts 13 is designed such that it is smaller than the radius of curvature of the contact part between the link plates 21 and the sliding surface (guide grooves 11). Therefore, the possibility of the link plates 21 fitting into the concave parts 13 provided on the sliding surface (guide grooves 11) is prevented.

[0008] Thus, the contact area between the link plates 21 and the guide shoe (chain guide 10) can be reduced without affecting the sliding of the chain 20, and the frictional resistance generated between the chain 20 and the guide shoe (chain guide 10) can be reduced.

[0009] Furthermore, the Japanese patent application JP 2015-137 685 A describes a chain guide 100 which has a guide shoe 120 in which a sliding surface (oil guide part 124) which has a pair of guide wall surfaces 124a which approach each other in a chain running direction D towards a front side is provided on a shoe surface 121.

[0010] In the guide shoe 120, lubricants contained in oil-receiving devices (concave shoe parts 122) are guided as the chain runs by means of the pair of guide wall surfaces 124a such that they approach each other on the sliding surface (oil guide part 124), and the pressure of the lubricants is increased at V-shaped wall approach parts 124b of the pair of guide wall surfaces 124a to increase the oil film thickness. Consequently, the guide shoe 120 can reduce the friction between the sliding surface and the chain CH and exhibits excellent wear resistance, thereby ensuring smooth chain operation. SUMMARY OF THE INVENTION

[0011] However, there is still room for improvement in each of the guide shoes known from the Japanese patent applications JP H08-303 541 A, JP 2015-218 756 A and JP 2015-137 685 A or the like.

[0012] This means that the sliding surface of each of the guide shoes, which are known from Japanese patent applications JP H08-303 541 A, JP 2015-218 756 A and JP 2015-137 685 A or similar, is in surface or line contact with the chain, and thus contact with the chain cannot be sufficiently reduced. Therefore, there is a possibility that sufficient friction and wear resistance cannot be ensured.

[0013] Furthermore, the lubricant, which is designed to be dispersed as the chain slides backward, cannot be collected. Therefore, there is a possibility that lubricant consumption cannot be reduced sufficiently.

[0014] Furthermore, in the guide shoe (chain guide 10) known from Japanese patent application JP H08-303 541 A, the convex parts of the irregularities formed by the creep process are provided on the sliding surface (contact surface 12A). However, if uneven surfaces formed by the creep process are pre-tensioned on the sliding surface (contact surface 12A), there is a possibility that some of the convex parts may not come into contact with the chain (timing chain 15) at all, and there is a possibility that the lubricant (oil) may not be retained to a sufficient degree on the entire sliding surface (contact surface 12A).

[0015] In the guide shoe known from Japanese patent application JP 2015-218 756 A, the semicircular irregularities, each with the same curvature, are continuously provided in the longitudinal direction of the sliding surface (guide grooves 11). However, if less lubricant (oil) is applied to the sliding surface (guide grooves 11) when starting an engine or the like, the chain 20 slides in a state where the amount of lubricant (oil) retained is insufficient and the lubricant (oil) is not adequately held on the convex parts 12. Therefore, there is a possibility that the sliding resistance will increase.

[0016] Furthermore, a chordal action occurs as the chain 20 slides on the periodically uneven sliding surface (guide grooves 11). Therefore, noise, accelerated wear, or similar issues may arise due to the collision between the link plates 21 and the convex parts 12.

[0017] In the guide shoe known from Japanese patent application JP 2015-137 685 A, the oil film thickness of the lubricant on parts where the chain CH slides is increased by the V-shaped wall approach parts 124b of the pair of guide wall surfaces 124a. Therefore, when the positional relationship between the end faces of the link plates L and the V-shaped wall approach parts 124b is interrupted, an increasing amount of the oil film thickness is pre-tensioned. Consequently, there is a possibility that the friction between the shoe surface 121 and the chain CH will not be reduced sufficiently.

[0018] Furthermore, if the lubricant in the oil-receiving devices (concave shoe parts 122) is insufficient when starting an engine or the like, the increasing amount of oil film thickness will be inadequate. Therefore, there is a possibility that the sliding resistance between the chain CH and the guide wall surfaces 124a will increase.

[0019] The present invention has been devised to solve the aforementioned problems, and its objective is to provide, with simple configurations, a guide shoe which, when the chain slides, exhibits a lower degree of sliding resistance between a chain and a sliding surface, is able to retain sufficient lubricant on the sliding surface even when starting an engine, and produces less noise and wear.

[0020] To solve the above problems, an embodiment of the present invention provides a guide shoe comprising: a sliding surface which guides a link plate of a running chain in a sliding manner; and a plurality of guide projections provided on the sliding surface, each of the guide projections having a vertex which projects in a vertical direction from the sliding surface, each of the front surfaces of the guide projections being designed such that it has a convexly curved surface in a chain running direction, at least from a part of the same on a front side to an upper part of the same.

[0021] In one embodiment of the present invention, a plurality of guide projections are provided, each having a vertex that projects vertically from a sliding surface. Therefore, the guide projections are in point contact with a chain. Consequently, the sliding resistance of the chain link plate on the sliding surface can be drastically reduced when the chain slides.

[0022] Furthermore, each of the leading surfaces of the guide projections is designed such that it has a convexly curved surface extending at least from a portion of it on a front side in the chain's direction of travel to an upper portion. Therefore, any lubricant that collects around the guide projections is gently guided along the curved surfaces of the guide projections to their upper portions by the movement of the running chain. Consequently, an oil film of sufficient thickness to reduce the sliding resistance between the link plate and the sliding surface as the chain moves can be stably formed.

[0023] In a further embodiment of the present invention, each of the front surfaces of the guide projections is designed such that it has a spherical shape from its lower portion on the sliding surface to its upper portion. Therefore, even if a strong force, caused by foreign objects or the like adhering to the guide projections, is unintentionally applied to them, the deformation of the guide projections is minimized. Consequently, the link plate of the chain can slide stably on the guide projections.

[0024] Furthermore, the lubricant running through the upper parts of the guide projections is gently collected without impeding the flow of the lubricant that collects around the guide projections. Consequently, lubricant dispersion is prevented.

[0025] The multitude of guide projections features projections arranged at different positions in the chain's direction of travel. The spacing between the upper portions of these projections, measured in the width of a shoe, is equal to or less than the thickness of the chain's link plate in the area where the chain link plate slides. Therefore, as the link plate traverses the sliding surface, it always makes contact with the upper portions of at least one or more of the guide projections, preventing the chain from falling into the concave sections between the guide projections. Consequently, stable chain operation is maintained.

[0026] The distance in the chain's running direction between the upper parts of the multiple guide projections is, viewed in the shoe width direction, one or less than the distance between the chain's pin pitches. Therefore, the link plate always comes into contact with the upper parts of at least one or more of the guide projections as it passes over the sliding surface, and the chain does not fall into the concave sections between the guide projections in the longitudinal direction. Consequently, the chain's more stable running is maintained.

[0027] In a further embodiment of the present invention, the plurality of guide projections are arranged offset on the sliding surface. Therefore, the density of the guide projections on the sliding surface can be increased. Consequently, the upper parts of the guide projections can ensure that each of the plurality of link plates runs more reliably.

[0028] In a further embodiment of the present invention, the guide shoe also has a concave, groove-shaped receiving hole provided on the sliding surface. Therefore, even if the lubricant that collects around the guide projections is dispersed by a vibration generated when the link plate slides on the sliding surface, the dispersed lubricant is collected in the receiving hole. Consequently, lubricant consumption can be reduced.

[0029] In a further embodiment of the present invention, the receiving hole is provided at at least one downstream end of the sliding surface in the direction of chain travel. Therefore, even if the lubricant applied to the chain link plate is caused to be dispersed downstream in the direction of chain travel after passing over the sliding surface, the lubricant can be collected in the receiving hole on the downstream side in the direction of chain travel. Consequently, the amount of lubricating oil consumed can be reduced more effectively.

[0030] The invention further relates to a chain guide according to claim 6 and to the use of a guide shoe according to claim 7. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A and Fig. Figure 1B shows a schematic view depicting a state in which a guide shoe according to an embodiment of the present invention is installed as part of a chain guide in a timing control system, and an enlarged perspective view of a part near a sliding surface; Fig. Figures 2A to 2C show enlarged perspective views illustrating a design state of the sliding surface of the guide shoe according to the embodiment of the present invention; Fig. Figure 3 shows a cross-sectional side view illustrating a state of development of the shoe surface of the guide shoe according to the embodiment of the present invention; Fig. Figures 4A to 4C each show a cross-sectional front view, an enlarged cross-sectional view and a cross-sectional side view illustrating a state in which a chain slides on the guide shoe according to the embodiment of the present invention; and Fig. Figures 5A to 5D show enlarged perspective views of a part near the sliding surface on a subordinate side in a chain direction, showing a design state of the shoe surface of the guide shoe according to a modified example of the embodiment of the present invention. DESCRIPTION OF THE PREFERRED EXECUTION FORM

[0031] The following is a description of a guide shoe 100 according to an embodiment of the present invention, with reference to the drawings.

[0032] As in Fig. 1A and Fig. As shown in Figure 1B, the guide shoe 100 is a component of a chain guide which is incorporated into a timing control system which is installed in an engine compartment, guides a chain 200 which runs between sprockets S and maintains an appropriate chain tensile force and has a sliding surface 111 which is used for the sliding of link plates 201 of the chain 200 on a shoe surface 110 which extends in a chain running direction D.

[0033] Furthermore, the guide shoe has 100 guide walls 115 on both sides in the shoe width direction.

[0034] At the downstream end in the chain direction D, a concave groove-shaped receiving hole 114 is provided transversely between the guide walls 115 on the sliding surface 111 of the shoe surface 110.

[0035] As in Fig. 2A to 2C and Fig. As shown in Figure 3, a plurality of guide projections 112, each having a vertex projecting in a vertical direction from the sliding surface 111, and oil guide elements 113, which are used to receive a lubricant around the guide projections 112, are provided on the sliding surface 111.

[0036] The guide projections 112 are spherical in shape to protrude from the sliding surface 111 and are arranged in a grid as shown in Fig. 2B is shown, but they can also be arranged in a staggered arrangement, as in Fig. 2C is shown.

[0037] Furthermore, the guide projections 112 are arranged such that the distance between the upper parts of the adjacent guide projections 112 becomes ta in both the chain running direction D and the shoe width direction.

[0038] As in Fig. As shown in Figures 4A to 4C, the chain has 200 outer link plates 201a, inner link plates 201b, rollers 203 and pins 204 and the link plates 201 are connected to the rollers 203 to be rotatable around the pins 204.

[0039] Furthermore, the inner link plates 201b are designed such that they are larger than the outer link plates 201a, and only the inner link plates 201b come into contact with the sliding surface 111 and slide on it.

[0040] Next, with reference to Fig. 4A to 4C describe the sliding of the chain 200 by means of the guide shoe 100 according to the embodiment.

[0041] First, an engine is started to make the chain run at 200.

[0042] A large frictional force may be generated on the surfaces where the chain 200 comes into contact with the sliding surface 111, as the chain 200 starts from a stationary state. However, the inner link plates 201b and the guide projections 112 are in point contact with each other. Therefore, the contact areas between the inner link plates 201b and the guide projections 112 are sufficiently small that no large frictional force is generated to such an extent that it affects the running of the chain 200. Consequently, the frictional force between the inner link plates 201b and the guide projections 112 is suppressed during the sliding of the chain 200, and deterioration, such as wear of the chain 200, can be prevented.

[0043] Furthermore, the guide projections 112 are designed such that they protrude from the sliding surface in a spherical shape. Therefore, even if a strong force is unintentionally applied to the guide projections 112, their deformation can be minimized. Consequently, the sliding of the inner link plates 201b on the sliding surface 111 can be stabilized.

[0044] Next, the lubricant that collects on the oil guide parts 113 forms an oil film between the inner link plates 201b and the guide projections 112 as the chain 200 slides on the sliding surface 111.

[0045] The guide projections 112 are designed such that they protrude from the sliding surface 111 in a spherical shape. Therefore, the lubricant is gently guided along the curved surfaces of the guide projections 112 by the movement of the running chain 200 to the upper parts of the guide projections 112, allowing it to form the oil film. Furthermore, the lubricant flowing through the upper parts of the guide projections 112 is gently collected without impeding the flow of lubricant that collects around the guide projections 112. Consequently, lubricant dispersion is prevented.

[0046] After the chain 200 has passed over the sliding surface 111, the inner link plates 201b separate from the guide projections 112.

[0047] It is likely that the lubricant applied to the inner link plates 201b as they slide on the guide projections 112, and the lubricant drawn from the sliding surface 111 by the force of the running chain 200, will be dispersed after the inner link plates 201b have detached from the sliding surface 111. However, the receiving hole 114 is located on the sliding surface at the downstream end in the chain direction D. Therefore, this lubricant can be collected in the receiving hole 114 and then supplied from the receiving hole 114 to the oil guide elements 113 for reuse. Consequently, lubricant consumption can be effectively reduced.

[0048] It should be noted that the guide projections 112 are arranged in a grid on the sliding surface 111 and are arranged such that the distance ta between the upper parts of the adjacent guide projections 112 becomes a plate width tb of the inner link plates 201b or less and a distance tc between the pin pitches of the chain 200 or less. Therefore, when the chain 200 passes through each position on the sliding surface 111, the inner link plates 201b come into contact with the upper parts of the guide projections 112 at two or more points.

[0049] Consequently, a failure of operation does not consist of the chain 200 falling into the oil guide parts 113 or getting stuck on the sliding surface 111, and the stabilized running of the chain 200 can be maintained, preventing the occurrence of noise.

[0050] The embodiment of the present invention has been described above. The present invention is not limited to the embodiment described above; rather, various modifications regarding the design can be made without thereby departing from the scope of the present invention as described in the claims.

[0051] It should be noted that the foregoing embodiment describes an example in which the guide projections are designed to protrude from the sliding surface in a spherical shape; however, the shape of the guide projections is not limited to this example. For instance, the guide projections can be designed to have a spherical shape only on their parts on the upstream and downstream sides in the chain direction relative to the upper parts.

[0052] Furthermore, the foregoing embodiment describes an example in which the guide projections are arranged in a grid or offset on the sliding surface; however, a method for arranging the guide projections is not limited to this example. For instance, the guide projections, which may have different shapes, can be arbitrarily arranged in a state in which the distance between the guide projections is smaller than the width of the inner link plates and the distance between the pin pitches of the chain.

[0053] Furthermore, the foregoing embodiment describes an example in which the concave, groove-shaped receiving hole is provided at the downstream end in the chain direction on the sliding surface of the shoe surface transversely between the guide walls; however, the shape and position of the receiving hole are not limited to this example. For example, as in Fig. As shown in Figure 5A, a plurality of receiving holes 114c are provided on the downstream side in the chain direction, while shoe surfaces 110c are provided without the guide projections 112 between the guide walls 115 and the sliding surfaces 111c. Alternatively, as shown in Fig. Figure 5B shows a trench-shaped receiving hole 114d that surrounds the perimeter of a sliding surface 111d.

[0054] Furthermore, the foregoing embodiment describes an example in which only the inner link plates come into contact with the guide projections; however, the contact relationship between the guide projections and the chain is not limited to this example. For instance, only the outer link plates may come into contact with the guide projections, or both the inner and outer link plates may come into contact with the guide projections. In the case of a noiseless chain, as in Fig. As shown in Figure 5C, shoe surfaces 110e can be provided between the guide walls 115 and a sliding surface 111e without the guide projections 112, on which the back surfaces of all plates do not slide in the width direction, while the sliding surface 111e is provided such that the back surfaces of all plates come into contact with the guide projections in the width direction.

[0055] Furthermore, the preceding embodiment describes an example in which the guide projections are provided uniformly in the entire width direction. In the case of a roller chain, however, positions in the width direction are restricted by the guide walls. Therefore, the positions in the width direction at which the link plates may slide are limited. Thus, as in Fig.As shown in Figure 5D, shoe surfaces 110f are provided without the guide projections 112 at positions in the width direction where the link plates do not slide, while sliding surfaces 111f are provided such that the guide projections 112 are only provided at the positions in the width direction.

Claims

[1] Chain guide with a guide shoe (100), and a chain (200) having link plates (201), held under tension by a tensioner (T), which runs between sprockets (S) of the chain guide and is guided slidably by the guide shoe (100). wherein the guide shoe (100) has: a sliding surface (111) which guides the link plates (201) of the running chain (200) in a sliding manner; and a plurality of guide projections (112) provided on the sliding surface (111), each of the guide projections (112) having a single vertex projecting in a vertical direction from the sliding surface (111), wherein each front surface of the guide projections (112) is designed such that it has a convexly curved surface at least from a part of the same on a front side to an upper part of the same in a chain travel direction, wherein the guide projections (112) on the sliding surface (111) are provided at the same distance from each other, wherein the plurality of guide projections (112) has guide projections which are arranged at different positions in the chain direction, wherein a distance (ta) in a shoe-width direction between the upper parts of the plurality of guide projections (112) in a region in which the link plate (201) of the chain (200) slides, seen in the chain running direction, is a plate thickness (tb) of the link plate (201) of the chain (200) or less, and where a distance (ta) in the chain running direction between the upper parts of the plurality of guide projections (112) seen in a shoe width direction is a distance (tc) between pin pitches of the chain (200) or less. [2] Chain guide according to claim 1, wherein each of the front surfaces of the guide projections (112) is designed such that it has a spherical shape from a part of the same on the sliding surface (111) to an upper part of the same. [3] Chain guide according to one of claims 1 to 2, wherein the plurality of guide projections are arranged offset on the sliding surface. [4] Chain guide according to one of claims 1 to 3, wherein the guide shoe (100) further comprises: a concave groove-shaped receiving hole (114) formed in the sliding surface (111). [5] Chain guide according to claim 4, wherein the receiving hole (114) is formed at least at a subordinate end in the chain running direction in the sliding surface (111). [6] Chain guide according to one of claims 1 to 5, wherein oil guide parts (113) are provided on the sliding surface (111) for receiving a lubricant around the guide projections (112), so that an oil film is formed between the link plates (201) and the guide projections (112) when the chain (200) slides on the sliding surface (111). [7] Use of a chain guide according to any one of claims 1 to 6 for guiding the chain (200) having link plates (201).

Images