chain

Abstract

An inner plate (10) of a chain is equipped with a rear surface which contacts a guide member which guides the chain when driving the chain. An inner plate rear surface which is equipped with sliding contact arc sections (102a, 102b) which are in sliding contact with a guide member, end arc sections (101a, 101b) which each comprise an end section of the inner plate on one side thereof, and connecting sections (C1, C2) which connect the interval between the sliding contact arc sections and the end arc sections, wherein a gap (V) is formed between the connecting section (C1) and the common tangent (TL) of the sliding contact arc section (102b) and the end arc section (101a).

Description

[Technical Field]

[0001] The present invention relates to a chain. [Background technology]

[0002] Conventionally, a power transmission chain wound around a crank sprocket and a cam sprocket has been proposed in which the outer shape of the inner link plates is elliptical (see Patent Document 1). More specifically, in this power transmission chain, the inner link plates are elliptical in shape, and the back surfaces that come into contact with the chain guide are arc-shaped, and the back surfaces of the outer link plates are lower in height than the inner link plates, so that only the arc-shaped back surfaces of the inner link plates come into sliding contact with the chain guide, thereby reducing the contact area with the chain guide and reducing friction loss between the chain guide and the chain guide. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5259775 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, forming the back surface of the inner link plate that slides against the chain guide into an arc shape reduces the contact area with the chain guide, thereby reducing friction loss between the chain and the chain guide. However, with such a chain, the contact pressure with the chain guide increases as the contact area with the chain guide decreases. This reduces the oil film thickness between the chain guide and the inner link plate, which increases the amount of wear on the chain guide due to contact between the chain and the chain guide. [Means for solving the problem]

[0005] The present invention provides a chain that can reduce wear on the guide members.

[0006] One aspect of the present invention is a chain comprising: a plurality of outer links each having a pair of outer plates and a pin connecting both ends of the pair of outer plates; a plurality of inner links each having a pair of inner plates and a bushing connecting both ends of the pair of inner plates, the inner plates having a back surface that contacts a guide member that guides the chain when the chain is driven; and the outer plates each having a pin hole into which the pin is inserted, a back surface that faces the guide member, and a front surface facing the back surface in a direction perpendicular to a pitch line connecting the centers of the pin holes; Equipped with The rear surface of the outer plate has a recess recessed toward the front surface between the centers of the pin holes, The back surface of the inner plate comprises a sliding arc portion that slides against the guide member, an end arc portion that includes one end of the inner plate, and a connecting portion that connects the sliding arc portion and the end arc portion, and a gap is formed between a common tangent to the sliding arc portion and the end arc portion and the connecting portion, and when the minimum distance from a pitch line connecting the centers of the pin holes to the back surface of the inner plate is defined as the back surface height of the inner plate and the minimum distance from the pitch line to the back surface of the outer plate is defined as the back surface height of the outer plate, the back surface height of the outer plate is higher at the position that overlaps with the center of the pin hole in the axial direction of the pitch line. One aspect of the present invention is a chain including a plurality of outer links each having a pair of outer plates and a pin connecting both ends of the pair of outer plates, and a plurality of inner links each having a pair of inner plates and a bushing connecting both ends of the pair of inner plates, the inner plates having a back surface that contacts a guide member that guides the chain when the chain is driven, the outer plates having pin holes into which the pins are inserted and a back surface that faces the guide member, and the back surface of the inner plates has a sliding contact that comes into sliding contact with the guide member. arc an end arc portion including an end portion on one side of the inner plate; arca connecting portion connecting the end arc portion and the end arc portion, the connecting portion having a connecting arc portion formed to have a smaller radius than the end arc portion, a gap is formed between the connecting portion and a common tangent line between the sliding contact arc portion and the end arc portion, If the minimum distance from the pitch line connecting the centers of the pin holes to the back surface of the inner plate is defined as the back surface height of the inner plate, and the minimum distance from the pitch line to the back surface of the outer plate is defined as the back surface height of the outer plate, then at the position where it overlaps with the center of the pin hole in the axial direction of the pitch line, the back surface height of the outer plate is higher than the back surface height of the inner plate. [Effects of the Invention]

[0007] A chain that can reduce wear on the guide members can be provided.

[0008] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a front view showing a timing chain transmission device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view of the timing chain according to the embodiment. [Figure 3] FIG. 2 is a side view of the timing chain according to the present embodiment. [Figure 4A] FIG. [Figure 4B] FIG. [Figure 4C] Enlarged view of part A in Figure 4A. [Figure 5A] Side view of the outer plate. [Figure 5B] Plan view of outer plate [Figure 5C] Enlarged view of part B in Figure 5A. [Figure 6] 3A and 3B are schematic diagrams for explaining the principle of oil film generation in the present embodiment. [Figure 7]Schematic diagram showing the chain when it comes into contact with a guide part with a small radius. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Configuration of timing chain transmission device)

[0011] An embodiment of the present invention will now be described with reference to the drawings. As shown in Fig. 1, a timing chain transmission device 1 disposed inside an engine includes a sprocket 2a fixed to a crankshaft 2, sprockets 3a, 3a fixed to two camshafts 3, 3, and a timing chain 5 wound around the crank sprocket 2a and the cam sprockets 3a, 3a. Two chain guides 6, 7 are in sliding contact with the tension side of the timing chain 5, which serves as a power transmission member, and a tensioner arm 8, which serves as a tension member, is in sliding contact with the slack side. The chain guides 6, 7 and tensioner arm 8 constitute a guide member 4 that guides the chain 5. The chain guides 6, 7 are fixed to the engine block, and one end of the tensioner arm 8 is pivotally supported by a support shaft 8b, with the other end abutting a plunger of a chain tensioner 9. The timing chain 5 is rotated while being given an appropriate tension by the chain tensioner 9 via the tensioner arm 8, and transmits power from the crankshaft 2 to the camshafts 3, 3.

[0012] (Timing chain configuration) Next, the configuration of the timing chain 5 will be described. As shown in Figures 2 and 3, the timing chain 5 has inner links 13, each of which has a pair of inner plates 10 connected at their opposite ends by bushings 11 and has rollers 12 rotatably fitted into the bushings 11, and outer links 17, each of which has a pair of outer plates 15 connected at their opposite ends by pins 16, with the inner links 13 and outer links 17 alternately and endlessly connected by inserting the pins 16 into the bushings 11. The inner links 13 are fixed by press-fitting the ends of the bushings 11 into bushing holes 10a, 10b formed in the inner plates 10, and the outer links 17 are fixed by fitting the ends of the pins 16 into pin holes 15a, 15b in the outer plates 15 and caulking.

[0013] As shown in FIG. 4A, the inner plate 10 has a substantially elliptical outer shape and is symmetrical about a pitch line L1 connecting the centers O1 and O2 of the pin holes 15a and 15b (bush holes 10a and 10b). Therefore, the circumferential surface of the inner plate 10 on the outer circumferential side of the chain 5 across the pitch line L1 (hereinafter referred to as the back surface) is symmetrical to the circumferential surface of the inner plate 10 on the inner circumferential side of the chain 5 across the pitch line L1 (hereinafter referred to as the front surface). The inner plate 10 also has a symmetrical shape about a transverse center axis L2 extending perpendicular to the pitch line L1 at the 1 / 2 pitch (1 / 2P) position. In the following description, the axial direction of the pitch line L1 is also referred to as the longitudinal direction, and the axial direction of the transverse center axis L2 is also referred to as the transverse direction (the up-down direction in the drawing). The intersection of the pitch line L1 and the transverse center axis L2 is the center O of the inner plate 10. P It is as follows.

[0014] The back surface of the inner plate 10 is provided with end arc portions 101a, 101b that form the left and right ends of the inner plate 10 in the longitudinal direction, a sliding contact portion S that comes into sliding contact with a guide member 4 of the chain 5, such as the chain guide 6 or the shoe 8a of the tensioner arm 8, and connection portions C1, C2 that connect the end arc portions 101a, 101b to the sliding contact portion S. The sliding contact portion S forms a sliding contact region that comes into sliding contact with the guide member 4 within the chain pitch P, and is provided with a first sliding contact arc portion 102a and a second sliding contact arc portion 102b. The first sliding contact arc portion 102a is formed by a symmetrical curve that protrudes outward in the circumferential direction and is centered at the 1 / 2 pitch position, and its center portion is located outward in the lateral direction from both end portions X1, X2. In addition, second sliding contact arc portions 102b are formed at both ends of the first sliding contact arc portion 102a, and the first sliding contact arc portion 102a is connected to the second sliding contact arc portion 102b at one end (first end) X1 and the other end (second end) X2.

[0015] In addition, one end X1 of the first sliding contact arc portion 102a is located at a position overlapping with the bushing hole 10a in the longitudinal direction and is closer to the center O1 of the inner plate 10 than the center O1 of the bushing hole 10a. P The other end X2 of the first sliding contact arc portion 102a is located at a position overlapping with the bushing hole 10b in the longitudinal direction and is closer to the center O2 of the inner plate 10 than the center O2 of the bushing hole 10b. P It is located on the side.

[0016] 4C is an enlarged view of part A in FIG. 4A, and the first connecting portion C1 includes a first connecting arc portion 103a that connects to the second sliding contact arc portion 102b, and a straight portion 103b. The second sliding contact arc portion 102b is located at the center O of the inner plate 10. P At the end X3 on the side, the inner plate 10 is connected to one end X1 of the first sliding contact arc portion 102, and at the end X4 on the opposite side, the inner plate 10 is connected to the first connecting arc portion 103a. PThe straight portion 103b is formed by a straight line, not a curved line that protrudes outward from the plate, as in the second sliding contact arc portion 102b and the first connecting arc portion 103a, and is connected to the end X4 of the second sliding contact arc portion 102b at the end X5 on the opposite side, and is connected to the straight portion 103b at the end X6 on the opposite side. P At the end X7 on the side, it is connected to the end X6 of the first connecting arc portion 103a described above, and at the end X8 on the opposite side, it is connected to the first end arc portion 101a.

[0017] The center O of the straight portion 103b P The end X7 on the side is positioned so as to overlap the center O1 of the bushing hole 10a in the longitudinal direction when viewed from the short side direction of the inner plate 10, and the second sliding contact arc portion 102b and the first connecting arc portion 103a described above overlap the bushing hole 10a in the longitudinal direction when viewed from the short side direction of the inner plate 10, and are positioned closer to the center O1 of the inner plate 10 than the center O1 of the bushing hole 10a. P The first end arc portion 101a is located on the side of the first connecting portion C1. The tangent line at the connecting position with the first connecting portion C1 is parallel to the pitch line L1 or is located on the side of the first connecting portion C1. P The inner plate 10 is formed so that the distance between the pitch line L1 and the tangent line on the back surface side of the inner plate 10 increases toward the center line L2. This allows the inner plate 10 to be formed with high strength.

[0018] Furthermore, if the radius of the first sliding contact arc portion 102a is RA, the radius of the first end arc portion 101a is RB, the radius of the second sliding contact arc portion 102b is RC, and the radius of the first connecting arc portion 103a is RD, the relationship of the radii is RA > RC > RB > RD. Furthermore, if the shortest distance from the pitch line L1 to the back surface is defined as the back surface height, and the back surface height at the 1 / 2 pitch position of the inner plate 10 is H1, and the back surface height at the end X8 is H2, then H1 > H2. Furthermore, the back surface height H1 is the maximum back surface height of the inner plate 10, and the back surface of the inner plate 10 has a convex shape with a high back surface height at the center. The relationship of the back surface heights at each end is: back surface height at end X1 (X3) > back surface height at end X4 (X5) > back surface height at end X6 (X7) = back surface height at end X8. Additionally, the inner plate 10 has a uniform thickness W1 throughout its entire length, as shown in FIG. 4B.

[0019] As described above, the inner plate 10 is formed line-symmetrically about the short-side central axis L2, and therefore the second sliding contact arc portion 102b and second connecting portion C2 on the right side in FIG. 4A are configured symmetrically with the second sliding contact arc portion 102b and first connecting portion C1 on the left side in FIG. 4A described above. Therefore, a detailed description of the second sliding contact arc portion 102b and second connecting portion C2 on the right side in FIG. 4A will be omitted. Furthermore, the inner plate 10 is formed line-symmetrically about the pitch line L1, and therefore the front surface of the inner plate 10 is configured symmetrically with the back surface of the inner plate 10 described above. Therefore, a detailed description of the front surface of the inner plate 10 will be omitted.

[0020] As shown in FIG. 5A, the outer plate 15 has a generally gourd-shaped (figure eight) outer shape and is symmetrical about the pitch line L3 connecting the centers O1 and O2 of the pin holes 15a and 15b. Therefore, the peripheral surface of the outer plate 15 on the outer periphery of the chain 5 across the pitch line L3 (hereinafter referred to as the back surface) is symmetrical to the peripheral surface of the outer plate 15 on the inner periphery of the chain 5 across the pitch line L3 (hereinafter referred to as the front surface). The outer plate 15 also has a symmetrical shape about a transverse center axis L4 extending perpendicular to the pitch line L3 at the 1 / 2 pitch (1 / 2P) position. In the following description, the axial direction of the pitch line L3 is also referred to as the longitudinal direction, and the axial direction of the transverse center axis L4 is also referred to as the transverse direction (the up-down direction in the drawing). The intersection of the pitch line L3 and the transverse center axis L4 is the center O of the inner plate 10. z It is as follows.

[0021] The back surface of the outer plate 15 is provided with end arc portions 151a, 151b that form the left and right ends of the outer plate 15 in the longitudinal direction, a concave arc portion 152, and connection portions D1, D2 that connect the end arc portions 151a, 151b and the concave arc portion 152. The concave arc portion 152 forms a concavely constricted region Z so as not to come into sliding contact with the chain guide 6 and the tensioner arm 8 within the chain pitch P, and is formed by a curve that convexly extends inward in the lateral direction. That is, the center of the concave arc portion 152 is located more inward in the lateral direction than both end portions Y1, Y2, and is connected to the first connection portion D1 at one end (first end) Y1 and to the second connection portion D2 at the other end (second end) Y2.

[0022] One end Y1 of the concave arc portion 152 is located at a position that overlaps with the pin hole 15a in the longitudinal direction and is closer to the center O1 of the outer plate 15 than the center O1 of the pin hole 15a. z Furthermore, the other end Y2 of the concave arc portion 152 is located at a position overlapping with the pin hole 15b in the longitudinal direction and closer to the center O2 of the outer plate 15 than the center O2 of the pin hole 15b. z It is located on the side.

[0023] 5C is an enlarged view of part B in FIG. 5A, and the first connecting portion D1 includes a connecting arc portion 153a and a straight portion 153b. The connecting arc portion 153a is located at the center O of the outer plate 15. z The end Y3 on the side of the outer plate 15 is connected to one end Y1 of the concave arc portion 152 described above, and the end Y4 on the opposite side is connected to the straight portion 153b. The straight portion 153b is formed by a straight line, not a curved line that protrudes outward from the plate like the connecting arc portion 153a described above, and is z At an end Y5 on the side, it is connected to the end Y4 of the connecting arc portion 153a described above, and at an end Y6 on the opposite side, it is connected to the first end arc portion 151a.

[0024] The straight portion 153b is located between the end Y5 and the end Y6 so as to overlap with the center O1 of the pin hole 15a in the longitudinal direction when viewed from the short side direction of the outer plate 15, and the connecting arc portion 153a is located so as to overlap with the pin hole 15a in the longitudinal direction when viewed from the short side direction of the inner plate 15, and is located closer to the center O1 of the outer plate 15 than the center O1 of the pin hole 15a. z It is located on the side.

[0025] Furthermore, if the radius of the concave arc portion 152 is RE, the radius of the first end arc portion 151a is RF, and the radius of the connecting arc portion 153a is RH, the relationship of the radii is RE>RF>RH. Furthermore, if the dimension (back surface height) in the short side direction from the pitch line L3 to the back surface (concave arc portion 152) at the 1 / 2 pitch position of the outer plate 15 is H3, and the dimension (back surface height) in the short side direction from the pitch line L3 to the back surface (first end arc portion 101a) at the end Y6 position is H4, then H4>H3. In this embodiment, the back surface height H3 is the minimum back surface height of the outer plate 15, and the back surface height H4 is the maximum back surface height. In addition, the outer plate 15 has a uniform thickness W2 over its entire length, as shown in FIG. 5B.

[0026] As described above, the outer plate 15 is formed line-symmetrically about the short-side central axis L4, and therefore the second connection portion D2 is configured to be symmetrical to the first connection portion D1 described above. For this reason, a detailed description of the second connection portion D2 will be omitted. In the following description, when describing the second connection portion D2, since it has the same structure as the first connection portion D1, the same reference numeral as the first connection portion D1 will be used. Furthermore, the outer plate 15 is formed line-symmetrically about the pitch line L3, and the front surface of the outer plate 15 is configured to be symmetrical to the back surface of the outer plate 15 described above. For this reason, a detailed description of the front surface of the outer plate 15 will be omitted.

[0027] (Oil film formation due to wedge effect)

[0028] Next, the principle of oil film generation due to the wedge effect based on the configuration of the connection portions C1, C2 of the inner plate 10 will be explained. FIG. 6 is a diagram showing the state in which the timing chain 5 moves in the traveling direction TD while sliding against the guide member 4. In this embodiment, the relative height relationship between the back surfaces of the inner plate 10 and the outer plate 15 is H1>H4>H2>H3. Therefore, the timing chain 5 usually slides against the guide member 4 only at the first sliding contact arc portion 102a of the inner plate 10. In addition, the first sliding contact arc portion 102a, which constitutes the sliding contact area S, is formed to protrude outward from the plate. This, combined with the fact that the first sliding contact arc portion 102a is formed to protrude outward from the plate, reduces the contact area of ​​the timing chain 5 with the guide member 4, resulting in low friction loss between the timing chain 5 and the guide member 4.

[0029] However, with the above configuration, the contact area of ​​the chain with the guide member 4 is reduced, resulting in an increased contact surface pressure at the contact point with the guide member 4 and a thinner oil film between the first sliding contact arc portion 102a of the inner plate 10 and the guide member 4. Furthermore, there is a risk that the amount of wear on the guide member 4 will increase due to the increased frequency of use in the boundary lubrication / mixed lubrication region. In particular, in recent years, the viscosity of lubricating oil (engine oil) has been decreasing in response to environmental regulations by automobile manufacturers, such as those aimed at improving engine fuel efficiency, and this could lead to an increased frequency of use in the boundary lubrication / mixed lubrication region.

[0030] Therefore, in this embodiment, connection portions C1 and C2 are formed between the sliding contact portion S of the inner plate 10 and the end arc portions 151a and 151b, so that high oil film pressure is generated between the sliding contact portion S and the guide member 4 even in a timing chain 5 that has a small contact area with the guide member 4 and a small friction loss. Below, the principle of oil film formation between the sliding contact portion S and the guide member 4 in this embodiment will be explained using the first connection portion C1 as an example.

[0031] 6, when the timing chain 5 moves in the traveling direction TD, lubricating oil is drawn into a wedge-shaped gap G formed between the back surface of the inner plate 10 and the guide member 4. When the lubricating oil is drawn into such a wedge-shaped gap G, an oil film pressure is generated by the so-called wedge effect, and an oil film is formed between the sliding contact portion S of the inner plate 10 and the guide member 4.

[0032] In particular, in the present embodiment, the inner plate 10 is formed to include a second sliding contact arc portion 102b, a first connecting arc portion 103a, and a straight portion 103b. As described above, the second sliding contact arc portion 102b and the first connecting arc portion 103a are formed to have smaller radii than the first sliding contact arc portion 102a. Furthermore, the first connecting arc portion 103a is formed to have an even smaller radius than the first end circular arc portion 101a, which has a smaller radius than the first sliding contact arc portion 102a (RA>RC>RB>RD). Therefore, the width of the wedge-shaped gap G is rapidly narrowed compared to when the first end circular arc portion 101a and the first sliding contact arc portion 102a are directly connected, allowing for an increase in compression pressure (oil film pressure). Furthermore, due to the presence of the straight portion 103b, the volume of the wedge-shaped gap G is larger than when the first end arc portion 101a and the first sliding contact arc portion 102a are directly connected, resulting in a higher oil film pressure. Therefore, the oil film formed between the first sliding contact arc portion 102a and the guide member 4 is thicker, which reduces wear between the first sliding contact arc portion 102a and the guide member 4 while maintaining low friction between them. Note that the second sliding contact arc portion 102b normally does not come into contact with the guide member 4, but may come into contact with the guide member 4 depending on the running state of the chain 5 and the shape of the guide member 4.

[0033] Furthermore, since the inner plate 10 is configured as described above, when a common tangent line TL is virtually drawn between the second sliding contact arc portion 102b and the first end arc portion 101a, as shown in FIG. 4C, it can be seen that a gap V is formed between the common tangent line TL and the connection portion C1, more specifically, between the common tangent line TL and the second sliding contact arc portion 102b, the first connection arc portion 103a, and the straight portion 103b.

[0034] Furthermore, in the timing chain 5 according to this embodiment, in the region where the pin hole / bush hole overlaps with the chain connection direction (more specifically, toward the first end arc portion 101a from the middle of the first connecting arc portion 103a), the outer plate 15 protrudes further outward from the chain 5 than the inner plate 10, covering part of the wedge-shaped gap G from the side. In other words, in this region, the back surface height of the outer plate is greater than that of the inner plate 10. This allows lubricating oil to be efficiently guided from the running direction of the chain 5 to the wedge-shaped gap G, which serves as the oil inlet region. Furthermore, the movement of lubricating oil escaping from the side to the outside when compressed in this region can be inhibited, further increasing the oil film pressure. Particularly in this embodiment, the straight portion 103b of the inner plate 10 extends the gap G as the oil inlet region. Furthermore, the straight portion 153b of the outer plate 15 also extends the oil inlet region over a long distance. Even in the region where the back surface of the outer plate 15 protrudes from the back surface of the inner plate 10, a predetermined gap exists between the back surface of the outer plate 15 and the guide member 4, and the outer plate 15 does not normally come into contact with the guide member 4. Furthermore, even if the chain 5 and the guide member 4 come into contact in the region where the back surface of the outer plate 15 protrudes from the back surface of the inner plate 10, depending on the running state of the chain and the shape of the guide, the outer plate 15 will have priority in contact with the inner plate 10, and the inner plate 10 will not come into contact with the guide member 4, or both the outer plate 15 and the inner plate 10 will come into contact with the guide member 4.

[0035] (Contact avoidance shape of outer plate) Next, the contact avoidance shape of the outer plate 15 will be described with reference to Figures 5A and 7. As described above, the back surface height is highest at the center of the inner plate 10. For this reason, the first sliding contact arc portion 102a of the inner plate 10 comes into contact with the guide member 4 preferentially, and the outer plate 15 does not come into contact with the guide member 4. However, if the radius of the guide member 4 is extremely small, there is a risk that the outer plate 15 will come into contact with the guide member 4.

[0036] For this reason, in this embodiment, a constricted region Z is formed on the back surface of the outer plate 15 within the range of pitch P, recessed toward the inner periphery, to provide a relief that prevents contact with the guide member 4. Note that in this embodiment, the constricted region Z is formed by the recessed arc portion 152 described above, but it is not necessarily required to form the constricted region Z by a curved line.

[0037] Because the outer plate 15 is configured in this manner, as shown in Figure 7, even if the radius of the guide member 4 is small, the outer plate 15 can be prevented from sliding against the guide member 4, and it is possible to prevent the outer plate 15 from coming into contact with the guide member 4 and increasing the sliding resistance of the chain.

[0038] (summary) <Disclosure 1> a plurality of outer links (17) each having a pair of outer plates (15) and a pin (16) connecting both ends of the pair of outer plates; A chain (5) comprising a pair of inner plates (10), bushings (11) connecting both ends of the pair of inner plates (10), and a plurality of inner links (13) alternately connected to the outer links (17), The inner plate (10) has a back surface that comes into contact with a guide member (4) that guides the chain (5) when the chain (5) is driven, The back surface of the inner plate is a sliding contact arc portion (102a, 102b) that is in sliding contact with the guide member; an end arc portion (101a, 101b) including one end of the inner plate; a connecting portion (C1, C2) connecting the sliding contact arc portion and the end arc portion, A gap (V) is formed between the common tangent (TL) of the sliding contact arc portion (102b) and the end arc portion (101a) and the connecting portion (C1). chain.

[0039] <Disclosure 2> The sliding contact arc portion includes a first sliding contact arc portion (102a) and a second sliding contact arc portion (102b) located between the first sliding contact arc portion and the connection portion, The radius (RC) of the second sliding contact arc portion is smaller than the radius (RA) of the first sliding contact arc portion (RA>RC). The chain according to Disclosure 1.

[0040] <Disclosure 3> The connecting portion includes a connecting arc portion (103a), The radius (RD) of the connecting arc portion is smaller than the radius (RA) of the first sliding contact arc portion (RA>RD). The chain according to Disclosure 1 or 2.

[0041] <Disclosure 4> The end arc portion has a smaller radius than the first sliding contact arc portion (RA>RB). The radius (RD) of the connecting arc portion (103a) is smaller than the radius (RB) of the end arc portions (101a, 101b) (RB>RD). The chain according to Disclosure 1 or 2.

[0042] <Disclosure 5> The connecting portion has a straight portion (103b) formed of a straight line. A chain according to any one of Disclosures 1 to 4.

[0043] <Disclosure 6> the outer plate includes pin holes (15a, 15b) into which the pins are inserted, a back surface facing the guide member, and a front surface facing the back surface in a direction perpendicular to a pitch line (L3) connecting the centers of the pin holes (15a, 15b), The back surface of the outer plate is provided with a recess (Z) recessed toward the front surface between the centers of the pin holes. A chain according to any one of Disclosures 1 to 5.

[0044] <Disclosure 7> When the minimum distance from the pitch line (L1) to the back surface of the inner plate is defined as the back surface height of the inner plate, and the minimum distance from the pitch line (L3) to the back surface of the outer plate is defined as the back surface height of the outer plate, At a position overlapping the center of the pin hole in the axial direction of the pitch line, a back height (H4) of the outer plate is higher than a back height (H2) of the inner plate (H4>H2). The chain according to disclosure 6.

[0045] <Disclosure 8> a plurality of outer links (17) each having a pair of outer plates (15) and a pin (16) connecting both ends of the pair of outer plates; A chain (5) comprising a pair of inner plates (10), bushings (11) connecting both ends of the pair of inner plates, and a plurality of inner links (13) connected alternately with the outer links (17), The inner plate (10) has a back surface that comes into contact with a guide member (4) that guides the chain (5) when the chain (5) is driven, The back surface of the inner plate is a sliding contact portion (102a, 102b) that is in sliding contact with the guide member; an end arc portion (101a, 101b) including one end of the inner plate; a connecting portion (C1, C2) connecting the sliding contact portion and the end arc portion, The connection portions (C1, C2) include a connection arc portion (103a) formed to have a radius smaller than that of the end arc portions (101a, 101b). chain.

[0046] Although the above-described embodiment has been described using a timing chain formed of a roller chain as an example, the present invention may also be applied to, for example, a bushing chain without rollers. The sliding contact portion S of the inner plate 10 may be formed by a single arc, by multiple arcs as in the above-described embodiment, or by a curve such as an involute curve. Additionally, the sliding contact portion S may be formed solely by a straight line, or by a combination of a sliding contact arc portion and a straight portion. Furthermore, the connection portions C1 and C2 of the inner plate 10 may be formed by a single arc, or, for example, by a single arc portion such as the first connecting arc portion 103a. Furthermore, the connection portions C1 and C2 of the inner plate 10 may be formed by multiple arcs, or, for example, by a combination of a first arc portion such as the second sliding contact arc portion 102b and a second arc portion such as the first connecting arc portion 103a without a straight portion. In this case, the end X6 of the second arc portion is located at the center O1 of the plate with the center O1 of the bushing hole 10a in between. P In terms of the strength of the plate, it is preferable that the center of the first arc portion is located on the opposite side of the center O1 of the bushing hole 10a. P Even if it is located on the opposite side of the plate, P Furthermore, in the above-described embodiment, the first connecting arc portion 103a is connected to the sliding contact portion S, and the straight portion 103b is connected to the first end arc portion 101a, but for example, the connecting arc portion and the first end arc portion 101a may be connected, and the straight portion and the sliding contact portion S may be connected.

[0047] In addition, the connection portions C1, C2 of the inner plate 10 may be configured by a curve such as an involute curve, and may naturally be combined with a straight portion as in the above-described embodiment.

[0048] In the above-described embodiment, the end X7 of the straight portion 103b is configured to overlap the center O1 of the bushing hole 10a. However, for example, the end X7 may be configured to be closer to the center O1 of the inner plate 10 than the center O1 of the bushing hole 10a. PThat is, regardless of the presence or absence of a straight portion, it is sufficient that a gap V can be formed between the common tangent TL between the second sliding contact arc portion 102b and the first end circular portion 101a and the connection portion C1, and that the first end circular portion 101a and the second sliding contact arc portion 102b are smoothly connected.

[0049] Furthermore, in the above-described embodiment, an example has been described in which the radius RC of the second sliding contact arc portion 102b is larger than the radius RB of the first end arc portion 101a, but the radius RC of the second sliding contact arc portion 102b may be formed to be smaller than the radius RB of the first end arc portion 101a. Also, an example has been described in which the radius RC of the second sliding contact arc portion 102b is larger than the radius RD of the first connecting arc portion 103a, but the radius RC of the second sliding contact arc portion 102b may be formed to be larger than the radius RD of the first connecting arc portion 103a.

[0050] Furthermore, the connection portions D1 and D2 of the outer plate 15 may be configured by a single arc, multiple arcs, or a curve such as an involute curve. Naturally, they may also be combined with a straight portion as in the above-described embodiment. In the above-described embodiment, one end Y1 of the concave arc portion 152 may be located closer to the center Oz of the outer plate 15 than the pin hole 15a in the longitudinal direction.

[0051] In addition, although the above embodiment has been described with reference to an example of a timing chain transmission device 1 having two camshafts 3, 3, the number of camshafts may be one. Also, in the above timing chain transmission device 1, an example has been described in which two chain guides 6, 7 are provided on the tension side, but a single or multiple chain guides may be provided. [Industrial Applicability]

[0052] The present invention can be widely implemented in the field of chains.

[0053] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention. [Explanation of symbols]

[0054] 4: guide member, 5: chain, 10: inner plate, 11: bushing, 13: inner link, 15: outer plate, 15a, 15b: pin hole, 16: pin, 17: outer link, 101a, 101b: end arc portion, 102a, 102b: sliding arc portion, 103a: first connecting arc portion, 103b: straight portion, S: sliding portion, C1, C2: connecting portion, TL: common tangent, V: gap, L1, L3: pitch line, Z: recess (necked area)

Claims

1. a plurality of outer links each having a pair of outer plates and a pin connecting both ends of the pair of outer plates; A chain including a pair of inner plates, bushings connecting both ends of the pair of inner plates, and a plurality of inner links alternately connected to the outer links, the inner plate has a back surface that comes into contact with a guide member that guides the chain when the chain is driven, the outer plate includes pin holes into which the pins are inserted, a back surface facing the guide member, and a front surface facing the back surface in a direction perpendicular to a pitch line connecting centers of the pin holes, The rear surface of the outer plate has a recess recessed toward the front surface between the centers of the pin holes, The back surface of the inner plate is a sliding contact arc portion that is in sliding contact with the guide member; an end arc portion including one end portion of the inner plate; a connecting portion connecting the sliding contact arc portion and the end arc portion, a gap is formed between the connecting portion and a common tangent line between the sliding contact arc portion and the end arc portion; When the minimum distance from a pitch line connecting the centers of the pin holes to the back surface of the inner plate is defined as the back surface height of the inner plate, and the minimum distance from the pitch line to the back surface of the outer plate is defined as the back surface height of the outer plate, a back surface height of the outer plate is higher than a back surface height of the inner plate at a position overlapping with a center of the pin hole in the axial direction of the pitch line; chain.

2. a plurality of outer links each having a pair of outer plates and a pin connecting both ends of the pair of outer plates; A chain including a pair of inner plates, bushings connecting both ends of the pair of inner plates, and a plurality of inner links alternately connected to the outer links, the inner plate has a back surface that comes into contact with a guide member that guides the chain when the chain is driven, the outer plate includes a pin hole into which the pin is inserted and a back surface facing the guide member, The back surface of the inner plate is a sliding contact arc portion that is in sliding contact with the guide member; an end arc portion including one end portion of the inner plate; a connecting portion connecting the sliding contact arc portion and the end arc portion, the connecting portion includes a connecting arc portion formed to have a smaller radius than the end arc portion, and is configured such that a gap is formed between the connecting portion and a common tangent line between the sliding contact arc portion and the end arc portion, When the minimum distance from a pitch line connecting the centers of the pin holes to the back surface of the inner plate is defined as the back surface height of the inner plate, and the minimum distance from the pitch line to the back surface of the outer plate is defined as the back surface height of the outer plate, a back surface height of the outer plate is higher than a back surface height of the inner plate at a position overlapping with a center of the pin hole in the axial direction of the pitch line; chain.

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