Link Plate

Abstract

The present invention provides a link plate and a chain which are highly versatile and easy to manufacture, can reduce friction resistance while maintaining the height of the guide side end surface at a low level, can suppress the surface pressure and ensure tensile strength. Specifically, the guide side end surface (120) of the link plate (101) is composed of a flat portion (121) and two side end surface portions (122), the flat portion (121) is composed of a flat surface parallel to a straight line connecting the center (C) of a front and rear connection hole (111), the two side end surface portions (122) are arranged on both sides of the flat portion (121) in the longitudinal direction of the chain, and the two side end surface portions (122) are formed so as to approach a straight line connecting the center of the front and rear connection holes (111) as they move away from the flat portion (121).

Description

Technical Field

[0001] The present invention relates to a link plate having front and rear connection holes, a sliding contact portion with a guide member, and a guide side end surface within a range connecting the centers of the front and rear connection holes in the longitudinal direction of the chain on the sliding contact portion side. Background Art

[0002] Conventionally, roller chains, bushing chains, silent chains, and the like used in power transmission mechanisms of automobiles, industrial machinery, and the like have known link plates having front and rear connection holes and having portions in sliding contact with guide members.

[0003] Since on a general chain, the entire guide side end surface within the range of the center of the front and rear connecting holes in the longitudinal direction of the chain on the sliding contact side (chain pitch interval) is formed by a flat surface, when the guide part in sliding contact has a flat surface or a large curvature radius, although the surface pressure can be reduced, the friction resistance increases.

[0004] In contrast, there is known a link plate which reduces frictional resistance by providing a concave curved portion on the guide side end surface or forming a special shape such as left-right asymmetry to control lubricating oil (see, for example, Patent Documents 1-4).

[0005] In addition, a link plate is known in which the guide side end surface is formed into a convex curved surface, which can reduce frictional resistance and ensure tensile strength by forming a shape that ensures the strength of the link plate around the connecting hole (for example, see Patent Document 5, etc.).

[0006] Patent Literature:

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-019749

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 11-236949

[0009] Patent Document 3: Japanese Patent Application Publication No. 2010-249240

[0010] Patent Document 4: Japanese Patent Application Publication No. 2011-231822

[0011] Patent Document 5: Japanese Patent Application Publication No. 2012-255523 Summary of the invention

[0012] Although the chain link plates known in Patent Documents 1-4 and the like can optimize the surface pressure and friction resistance, they vary greatly due to the viscosity and temperature of the lubricating oil and the surface condition of the guide parts, and therefore require different designs depending on the use environment. Furthermore, since they need to be manufactured with high precision according to the design, there are problems such as low versatility and increased manufacturing costs.

[0013] Although the link plate disclosed in Patent Document 5 has a high effect of reducing the frictional resistance, other measures need to be taken to increase the surface pressure on the guide member and eliminate the adverse effects caused by wear marks and abrasive powder.

[0014] Furthermore, there is a problem that the maximum height of the link plate must be increased more than necessary in order to increase the strength of the link plate around the connection hole.

[0015] The present invention is an invention for solving the problems of the prior art as described above. The technical problem to be solved is to provide a link plate and a chain which are highly versatile and easy to manufacture, can reduce frictional resistance while maintaining the height of the guide side end face at a low level, can reduce surface pressure and improve tensile strength.

[0016] The chain link plate involved in the present invention has front and rear connecting holes, and has a sliding contact portion with a guide component, and has a guide side end face within the range of the center of the front and rear connecting holes connected in the longitudinal direction of the chain on the side of the sliding contact portion. It solves the above-mentioned problem by the following contents, namely, the guide side end face is composed of a flat portion and two side end face portions, the flat portion is composed of a flat surface parallel to a straight line connecting the centers of the front and rear connecting holes, the two side end face portions are arranged on both sides of the flat portion in the longitudinal direction of the chain, and the two side end face portions are formed to approach the straight line connecting the centers of the front and rear connecting holes as they move away from the flat portion.

[0017] According to the link plate involved in the present design scheme 1 and the chain involved in the present design scheme 6, since the guide side end face is composed of a flat portion and two side end face portions, the flat portion is composed of a flat surface parallel to the straight line connecting the centers of the front and rear connecting holes, the two side end face portions are arranged on both sides of the flat portion in the longitudinal direction of the chain, and the two side end face portions are formed so as to approach the straight line connecting the centers of the front and rear connecting holes as they move away from the flat portion. Therefore, the same friction reduction effect as the link plate whose guide side end face is a convex curved surface as a whole can be maintained, and the surface pressure can be suppressed to a lower level. In addition, the maximum height of the link plate can be suppressed to a lower level while ensuring the tensile strength.

[0018] Moreover, the shape is simple and the design difficulty is relatively low, and it is highly versatile and easy to manufacture.

[0019] According to the structure described in the present design scheme 2, since the distance (H / 2) from the flat portion to the center of the connecting hole connecting the front and rear ends is longer than the distance (R) from the center of the connecting hole to the front and rear end of the link plate on the straight line connecting the center of the front and rear connecting holes, the width of the link plate around the connecting hole can be ensured, thereby effectively improving the tensile strength.

[0020] According to the structure described in the present design scheme 3, since the end surfaces on both sides are composed of curved surfaces with a specified curvature radius (RT), and the curvature radius (RT) of the end surfaces on both sides is longer than the distance (R) from the center of the connecting hole to the front and rear ends of the chain link plate on the straight line connecting the centers of the front and rear connecting holes, a smooth surface is formed from the end surfaces on both sides to the flat portion, so that when the chain moves, it can smoothly enter the guide component, thereby reducing impact and noise.

[0021] According to the structure described in the present design scheme 4, since the length (L) of the flat portion in the longitudinal direction of the chain is less than 50% of the length (P) between the centers of the front and rear connecting holes, it is possible to effectively achieve the same friction reduction effect as that of a link plate whose entire guide side end face is a convex curved surface.

[0022] According to the structure described in the fifth design solution, since the end surfaces on both sides are smoothly connected with the flat portion as a tangent at the connection point with the flat portion, even if the link plate vibrates or changes its posture, the change in the sliding resistance with the guide component can be suppressed, thereby achieving stable sliding. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a perspective view of the chain according to the first embodiment of the present invention.

[0024] Figure 2 It is a side view of the link plate according to the first embodiment of the present invention.

[0025] Figure 3 It is a test curve diagram of the chain of the present invention.

[0026] Explanation of symbols

[0027] 100-chain; 101-inner link plate; 102-outer link plate; 103-bushing; 104-pin; 111-bushing hole (connecting hole); 112-front and rear end faces; 120-guide side end face; 121-flat portion; 122-side end face portions; 123-side end face extension portions; C-center of connecting hole; H-link plate height; L-length of flat portion; P-length between centers of connecting holes (chain pitch); RT-radius of curvature of side end face portions (side end face extension portions); R-radius of curvature of front and rear end faces (the distance from the center of the connecting hole to the front and rear end of the link plate on the straight line connecting the centers of the front and rear connecting holes); r-radius of connecting hole; W-link plate width directly above the center of the connecting hole; LL-front and rear length of link plate; Y-boundary point between side end face extension portions and front and rear end faces. DETAILED DESCRIPTION

[0028] like Figure 1 As shown, a chain 100 using an embodiment of the present invention, i.e., an inner link plate 101, comprises a pair of left and right inner link plates 101, a cylindrical bushing 103 whose both ends are press-fitted into a connecting hole, i.e., a bushing hole 111, of the inner link plate 101, a pair of left and right outer link plates 102 arranged on both outer sides of the inner link plate 101, and a connecting pin 104 rotatably inserted into the bushing 103 and whose both ends are press-fitted into a pin hole of the outer link plate 102, and the connecting pin 104 is used to alternately connect a plurality of inner link plates 101 and outer link plates 102 in the longitudinal direction of the chain.

[0029] like Figure 1 , Figure 2 As shown, the inner link plate 101 is symmetrical in shape in both vertical and horizontal directions, and the guide side end surface 120 is composed of a flat portion 121 and two side end surface portions 122. The flat portion 121 is composed of a flat surface parallel to a straight line connecting the centers of the front and rear connecting holes 111. The two side end surface portions 122 are arranged on both sides of the flat portion 121 in the longitudinal direction of the chain, and the two side end surface portions 122 are formed so as to approach a straight line connecting the centers of the front and rear connecting holes 111 as they move away from the flat portion 121.

[0030] In addition, if Figure 2 As shown, in the present embodiment, the front and rear end surfaces 112 in the longitudinal direction of the inner link plate 101 are formed of arc surfaces having a curvature radius R centered at the center C of the connection hole 111 .

[0031] The side end surface portions 122 and the side end surface extension portions 123 are arc surfaces with a curvature radius RT. The tangent lines at the connection points of the side end surface portions 122 with the flat portion 121 are consistent with the flat portion 121. The side end surface extension portions 123 and the front and rear end surfaces 112 have the same tangent lines at their boundary points Y.

[0032] Therefore, from the flat portion 121 to the front and rear end surfaces 112 , the two side end surface portions 122 and the two side end surface extension portions 123 are smoothly connected and have no corners.

[0033] The length L of the flat portion 121 is set to be less than or equal to 50% of the chain pitch P, which is the length between the centers C of the front and rear connection holes 111 .

[0034] The curvature radius RT of the side end surface portions 122 and the side end surface extension portions 123 is larger than the curvature radius R of the front and rear end surfaces 112 which is the distance from the center C of the connecting hole 111 to the front and rear ends of the inner link plate 101 on a straight line connecting the centers of the front and rear connecting holes 111 .

[0035] Therefore, the link plate width around the connecting hole 111 gradually widens from the boundary point Y toward the side end surface extensions 123 , and just above the center C of the connecting hole 111 , the link plate width W>Rr (radius of the connecting hole 111 ).

[0036] In addition, the distance from the flat portion 121 to the center of the front and rear connecting holes 111, that is, half the height H of the inner link plate 101 = H / 2, is longer than the distance from the center of the connecting hole 111 to the front and rear ends of the inner link plate 101 on the straight line connecting the centers of the front and rear connecting holes 111, that is, the curvature radius R of the front and rear end surfaces 112.

[0037] By having these dimensional relationships, the tensile strength can be increased.

[0038] The dimensional relationship of the inner link plates of this embodiment is summarized as follows.

[0039] LL=P+2R

[0040] L≦P / 2

[0041] R <H / 2

[0042] R <RT

[0043] R <W

[0044] LL: Front and rear length of link plate

[0045] P: Chain pitch (length between the centers C of the connecting holes 111)

[0046] R: Curvature radius of the front and rear end surfaces 112 (the distance from the center C of the connecting hole 111 to the front and rear ends of the inner link plate 101 on the straight line connecting the centers C of the front and rear connecting holes 111)

[0047] L: length of the flat portion 121

[0048] H: Height of the inner link plate 101 (twice the distance of the straight line from the flat portion 121 to the center C of the connecting holes 111 before and after)

[0049] RT: The curvature radius of the end surfaces on both sides and the extensions of the end surfaces on both sides

[0050] W: Width of the link plate directly above the center C of the connecting hole 111

[0051] r: Radius of the connecting hole 111

[0052] In addition, although Figure 2 In the embodiment shown, the center of the curvature radius R of the front and rear end surfaces 112 is used as the center C of the connecting hole 111, but when the front and rear length LL of the link plate is kept constant and the length L of the flat portion 121 is changed, the size and center position of the curvature radius R of the front and rear end surfaces 112 also change in conjunction.

[0053] At this time, within the above conditions, only the condition except LL=P+2R needs to be satisfied.

[0054] Figure 3 Experimental data are shown on the fuel efficiency improvement rate (mainly depending on the friction resistance caused by the length of the flat portion 121) and the strength improvement rate (mainly depending on the link plate width just above the center C of the connecting hole 111) when the chain 100 using the inner link plate 101 constructed in this way is used in the timing system of the engine.

[0055] All link plates have the same chain pitch (the length between the centers C of the connection holes 111 ) P, the same height H of the inner link plate 101 , and the same link plate front-rear length LL, but different lengths L of the flat portions 121 .

[0056] The case where the length L of the flat portion 121 relative to the chain pitch (the length between the centers C of the connecting holes 111) P is L / P=0% is a chain using a link plate with a convex curved surface on the guide side end surface as is known in the aforementioned patent document 5, and the case of L / P=0% is plotted as a strength improvement rate of 100%.

[0057] The case of L / P=100% is a chain using a general link plate whose guide-side end surface is entirely flat, and this case of L / P=100% is plotted as a fuel efficiency improvement rate of 100%.

[0058] It can be seen from the experimental data that the strength improvement rate increases roughly linearly with the increase of L / P.

[0059] This is because, when the height H of the inner link plate 101 and the link plate front-rear length LL are the same, the longer the length L of the flat portion 121 is, the larger the link plate width W directly above the center C of the connection hole 111 is.

[0060] On the other hand, up to around L / P=50%, the fuel efficiency improvement rate is maintained at a high level even if L / P is increased, and decreases suddenly when L / P exceeds 50%.

[0061] This means that in general usage environments where lubricating oil is present and there is surface deformation of the guide component due to the influence of surface pressure, there is almost no increase in frictional resistance that causes deterioration in fuel consumption, even if there is a flat portion to a certain extent, compared to a chain link plate in which the guide side end surface is formed as a convex curved surface.

[0062] In addition, although the inner link plate 101 is used in the above embodiment, the outer link plate 102 may be formed into the same structure to be in sliding contact with the guide member.

[0063] In addition, although Figure 2 The shape is symmetrical in vertical and horizontal terms when viewed from the side, but when used as a link plate of a silent chain, for example, it may be asymmetrical in vertical terms if it is limited to having a sliding contact portion with a guide component only on one side.

[0064] Furthermore, in order to specify the moving direction or to make the characteristics different depending on the moving direction, it may be left-right asymmetric.

[0065] In addition, although the two side end surface portions 122 and the two side end surface extension portions 123 are formed into curved surfaces with the same curvature radius RT, curved surfaces with different radii can also be formed, and the two side end surface portions 122 and the two side end surface extension portions 123 can also be formed by inclined planes or curved surfaces with changing radii.

[0066] In addition, although the front and rear end faces 112 are formed into curved surfaces with a curvature radius R, they can also be formed by a combination of planes or curved surfaces with a changing radius, or they can also be formed by a curved surface connected to the end face extensions 123 on both sides and with a changing radius.

[0067] Furthermore, although it is preferred that the boundaries of the flat portion 121, the two side end face portions 122, the two side end face extension portions 123, and the front and rear end faces 112 are smoothly connected, they can also be corners with convex or concave angles (including cases where they are connected with smaller rounded corners or corners).

Claims

1. A link plate having front and rear connection holes, a sliding contact portion that comes into sliding contact with a guide member, and a guide side end surface within the range of a line segment connecting the centers of the front and rear connection holes in the longitudinal direction of the chain on the sliding contact portion side, characterized in that: The guide side end surface is composed of a flat portion and two side end surface portions, the flat portion is composed of a flat surface parallel to a straight line connecting the centers of the front and rear connection holes, and only one flat portion is provided within a range including the center in the longitudinal direction of the sliding contact portion, and the two side end surface portions are provided on both sides of the flat portion in the longitudinal direction of the chain, The side end surfaces are formed so as to approach a straight line connecting the centers of the front and rear connection holes as they are separated from the flat portion. The length L of the flat portion in the longitudinal direction of the chain is equal to or less than 50% of the length P between the centers of the front and rear connecting holes.

2. The link plate according to claim 1, characterized in that: A distance H / 2 from the flat portion to the straight line connecting the centers of the front and rear connecting holes is longer than a distance R from the center of the connecting hole to the front and rear ends of the link plate on the straight line connecting the centers of the front and rear connecting holes.

3. The link plate according to claim 1 or claim 2, characterized in that: The two side end surfaces are formed by curved surfaces with a predetermined curvature radius RT. The curvature radius RT of the side end surface portions is longer than a distance R from the center of the connecting hole to the front and rear ends of the link plate on a straight line connecting the centers of the front and rear connecting holes.

4. The link plate according to claim 1 or claim 2, characterized in that: The two side end surface portions are smoothly connected to the flat portion at connection points with the flat portion, with the flat portion serving as a tangent line.

5. A chain comprising a pair of left and right inner link plates, a pair of left and right outer link plates respectively arranged on both outer sides of the pair of left and right inner link plates, and a plurality of the inner link plates and the outer link plates are alternately connected in the longitudinal direction of the chain by connecting pins, characterized in that: The pair of left and right inner link plates is composed of the link plate according to any one of claims 1 to 4.

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