Abstract:
The invention provides a chain and a chain guide plate that suppress occurrence of noise during chain traveling while attaining a reduction in costs and also attaining space saving. A chain includes first plate rows and second late rows. Each of the first plate rows includes a guide plate including a guide slide contact section for coming into slide contact with an inner side guide. The guide slide contact section extends in a chain longitudinal direction to be asymmetrical relative to an imaginary center line. During guiding by the inner side guide, lines drawn by the guide slide contact sections of a plurality of the guide plates are continuous in the chain longitudinal direction.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a chain configured by alternately arranging in a shifted position by a half pitch in a chain longitudinal direction first plate rows and second plate rows including a plurality of plates arranged in parallel in a chain width direction, with these rows being bendably coupled to one another, and also relates to a chain guide plate used for the chain. 
         [0003]    2. Description of the Related Art 
         [0004]    There has been known a chain  500  configured by, as shown in  FIG. 10 , alternately arranging in a shifted position by a half pitch in a chain longitudinal direction, first plate rows  510  including a plurality of plates  520  and  530  arranged in parallel in a chain width direction and second plate rows  540  including a plurality of plates  550  arranged in parallel in the chain width direction, with these rows being bendably coupled with one another with coupling pins  560  (see, for example, Japanese Patent Application Laid-Open No. H10-238597 (Patent Literature 1)). 
         [0005]    As a guide method for the chain  500 , various methods are known. As one of the methods, there is known a method of setting an outer side guide on the outer side of a chain traveling track and bringing rear surfaces (end faces on a chain bending outer circumferential side) of the plates  520 ,  530 , and  550  into slide contact with a shoe surface of the outer side guide. However, to set the outer side guide, it is necessary to secure an attachment space for the outer side guide on the outer side of the chain traveling track. Therefore, it is sometimes difficult to use the outer side guide depending on an environment of use of the chain  500 . 
         [0006]    As another guide method for the chain  500 , it is also known to set an idler sprocket halfway in the chain traveling track. However, it is sometimes difficult to use the idler sprocket in terms of a setting space and costs because, for example, it is necessary to set a sprocket shaft and a bearing mechanism to set the idler sprocket. 
         [0007]    Therefore, as a method of solving the problems of the setting space and the costs in using the outer side guide and the idler sprocket explained above, there is known a method of, as shown in  FIG. 11 , setting an inner side guide G on the inner side of the chain traveling track, bringing guide slide contact sections  524  formed on a chain bending inner circumferential side of guide plates  520  into slide contact with a shoe surface G 1  of the inner side guide G, and guiding the chain  500 . 
         [0008]    However, when the chain  500  is guided using the inner side guide G, in the conventional chain  500 , as shown in  FIG. 11 , spaces D are formed among the guide slide contact sections  524  of the guide plates  520 . Therefore, during chain traveling, the plurality of guide slide contact sections  524  intermittently collide with the shoe surface G 1  of the inner side guide G. Noise occurs because of the intermittent collision. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention has been devised to solve the problems and it is an object of the present invention to provide a chain and a chain guide plate that suppress occurrence of noise during chain traveling while attaining a reduction in costs and also attaining space saving. 
         [0010]    According to an aspect of the present invention, there is provided a chain configured by alternately arranging in a shifted position by a half pitch in a chain longitudinal direction first plate rows and second plate rows including a plurality of plates arranged in parallel in a chain width direction, with these rows being bendably coupled to one another, wherein each of the first plate rows includes a guide plate including a pair of pin holes formed side by side in the chain longitudinal direction and a guide slide contact section for coming into slide contact with an inner side guide arranged on a chain bending inner circumferential side, the guide slide contact section extends in the chain longitudinal direction to be asymmetrical relative to an imaginary center line extending in a chain height direction through a center of the pair of pin holes, and during guiding by the inner side guide, lines drawn by the guide slide contact sections of a plurality of the guide plates are continuous in the chain longitudinal direction when viewed in the chain width direction. Consequently, the problems are solved. 
         [0011]    According to another aspect of the present invention, there is provided a chain guide plate including a guide slide contact section for coming into slide contact with an inner side guide arranged on a chain bending inner circumferential side. The guide plate includes a pair of pin holes formed side by side in a chain longitudinal direction and the guide slide contact section. The guide slide contact section extends in the chain longitudinal direction to be asymmetrical relative to an imaginary center line extending in a chain height direction through the center of the pair of pin holes. Consequently, the problems are solved. 
         [0012]    In inventions according to claims  1  and  7 , a guide slide contact section of a guide plate is formed to extend in a chain longitudinal direction to be asymmetrical relative to an imaginary center line. During guiding by an inner side guide, lines drawn by guide slide contact sections of a plurality of guide plates are made continuous in a chain longitudinal direction. Therefore, it is possible to suppress occurrence of noise due to intermittent collision of the plurality of guide plates with the inner side guide while avoiding an increase in the number of guide plates and complication of a chain structure. 
         [0013]    In an invention according to claim  2 , each of the first plate rows includes two guide plates arranged in a state in which directions of the guide plates in the chain longitudinal direction are reversed each other. Therefore, it is possible to make, using the guide plates having the same shape, the lines drawn by the guide slide contact sections of the plurality of guide plates continuous in the chain longitudinal direction. 
         [0014]    In an invention according to claim  3 , the guide plates are arranged on both outer sides, in the chain width direction, of each of the first plate rows. Consequently, it is possible to improve contact balance between the guide plates and the inner side guide. Further, it is possible to cause the guide plates to play a function of preventing disengagement of the chain and a sprocket. 
         [0015]    In an invention according to claim  4 , the guide slide contact section includes a plurality of curved concave surface sections having different curvature radiuses. Therefore, when a plurality of inner side guides having different curvature radiuses are used, it is possible to satisfactorily maintain a contact state of the inner side guides and the guide plate. 
         [0016]    In an invention according to claim  5 , a curvature center of a curved concave surface section formed in a position crossing the imaginary center line is located on the imaginary center line. Therefore, it is possible to satisfactorily set the entire surface of the curved concave surface section in contact with a curved shoe surface of the inner side guide. 
         [0017]    In an invention according to claim  6 , a curvature radius of a second curved concave surface section arranged adjacent to the curved concave surface section formed in the position crossing the imaginary center line is set larger than a curvature radius of the curved concave surface section. Therefore, it is possible to prevent the second curved concave surface section from hindering slide contact of the curved concave surface and the inner side guide. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a perspective view showing a chain in a first embodiment; 
           [0019]      FIG. 2  is an explanatory diagram showing a use form of the chain in the first embodiment; 
           [0020]      FIG. 3  is an explanatory diagram showing guide plates in the first embodiment; 
           [0021]      FIG. 4  is an explanatory diagram showing a contact state of the guide plates and an inner side guide in the first embodiment; 
           [0022]      FIG. 5  is a use form diagram showing a chain in a second embodiment; 
           [0023]      FIG. 6  is an explanatory diagram showing guide plates in the second embodiment; 
           [0024]      FIG. 7  is an explanatory diagram showing a contact state of the guide plates and an inner side guide in the second embodiment; 
           [0025]      FIG. 8  is an explanatory diagram showing a first modification of the guide plates in the second embodiment; 
           [0026]      FIG. 9  is an explanatory diagram showing a second modification of the guide plates in the second embodiment; 
           [0027]      FIG. 10  is a perspective view showing a conventional chain; and 
           [0028]      FIG. 11  is an explanatory diagram showing a use form of the conventional chain. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments 
       [0029]    A chain  100  according to a first embodiment of the present invention is explained below with reference to  FIGS. 1 to 4 . 
         [0030]    The chain  100  in the first embodiment is configured as a timing chain incorporated in a timing system for an automobile engine. As shown in  FIG. 2 , the chain  100  travels on a predetermined track in a state in which the chain  100  is wound around a plurality of sprockets (not shown in the figure) and a chain bending inner circumferential side is guided by an inner side guide G having a flat shoe surface G 1 . The inner side guide G is configured as a fixed guide fixed to a peripheral section or the like of an engine block or the like or a swinging guide swingably attached to the peripheral section and pressed to the chain  100  side by a tensioner. 
         [0031]    In the chain  100 , as shown in  FIG. 1 , a plurality of first plate rows  110  and a plurality of second plate rows  140  are shifted by a half pitch in a chain longitudinal direction, alternately arranged, and bendably coupled. 
         [0032]    As shown in  FIG. 1 , the first plate row  110  is configured from a pair of guide plates  120  arranged on both outer sides in a chain width direction and a plurality of first inner plates  130  arranged between the pair of guide plates  120 . The second plate row  140  is configured from a plurality of second inner plates  150  arranged in parallel in the chain width direction. 
         [0033]    Each of the guide plate  120 , the first inner plate  130 , and the second inner plate  150  includes a pair of pin holes formed side by side in the chain longitudinal direction. The plurality of first plate rows  110  and the plurality of second plate rows  140  are bendably coupled by inserting coupling pins  160  into the pin holes of the first inner plates  130  and the second inner plates  150  in a loose fit state and fixing both end sides of the coupling pins  160  to pin holes  121  of the guide plates  120 . Each of the first inner plate  130  and the second inner plate  150  includes a pair of V-shaped link teeth for meshing with a sprocket (not shown in the figure) on a chain bending inner circumferential side. 
         [0034]    A specific form of the guide plate  120  most characterizing the chain  100  in this embodiment is explained below. 
         [0035]    The guide plate  120  includes, as shown in  FIG. 3 , a plate base section  122  including a pair of pin holes  121  formed side by side in the chain longitudinal direction and a plate swelling section  123  swelling to the chain longitudinal direction side from one end edge in the chain longitudinal direction of the plate base section  122 . The plate base section  122  is formed in a symmetrical shape with respect to an imaginary center line L extending in a chain height direction through the center of the pair of pin holes  121 . 
         [0036]    On the end face on the chain bending inner circumferential side of the guide plate  120 , as shown in  FIG. 3 , a guide slide contact section  124  for coming into slide contact with the inner side guide G is formed. In this embodiment, the guide slide contact section  124  is configured from a flat surface section  124   a  and formed over the plate base section  122  and the plate swelling section  123 . The guide slide contact section  124  extends in the chain longitudinal direction to be asymmetrical relative to the imaginary center line L. 
         [0037]    As it is seen from  FIGS. 1 and 4 , the pair of guide plates  120  included in each of the first plate rows  110  is arranged in a state in which directions in the chain longitudinal direction of the guide plates  120  (swelling directions of the plate swelling sections  123 ) are reversed each other. Consequently, as shown in  FIG. 4 , lines drawn by the guide slide contact sections  124  of the plurality of guide plates  120  during guiding by the inner side guide G are continuous in the chain longitudinal direction when viewed in the chain width direction. Note that, in  FIG. 4 , the guide plates  120  located on the paper surface front side are hatched and the guide plates  120  located on the paper surface inner side are not hatched. 
         [0038]    A chain  200  according to a second embodiment of the present invention is explained with reference to  FIGS. 5 to 9 . The second embodiment is the same as the first embodiment except a part of the configuration. Therefore,  100  series reference numerals described in the specification and the drawings concerning the first embodiment are replaced with  200  series reference numerals, whereby explanation of the components other than differences is omitted. 
         [0039]    As shown in  FIG. 5 , the chain  200  in the second embodiment travels in a state in which the chain  200  is guided by the inner side guide G including the shoe surface G 1  having a curved convex surface shape. Accordingly, a guide slide contact section  224  of a guide plate  220  is configured from a single curved concave surface section  224   b.  The curved concave surface section  224   b  is formed to be curved at a curvature radius same as the curvature radius of the shoe surface G 1  of the inner side guide G centering on a bending center located on the imaginary center line L. 
         [0040]    The guide plate  220  according to a first modification of the second embodiment is explained with reference to  FIG. 8 . 
         [0041]    In the guide plate  220  in the first modification, as shown in  FIG. 8 , the guide slide contact section  224  is configured from a first curved concave surface section  224   c  and a second curved concave surface section  224   d  having different curvature radiuses. 
         [0042]    As shown in  FIG. 8 , the first curved concave surface section  224   c  is formed in a position crossing the imaginary center line L and formed to be curved at a curvature radius R 1  centering on a bending center C 1  located on the imaginary center line L. The second curved concave surface section  224   d  is formed adjacent to the first curved concave surface section  224   c  and formed to be curved at a curvature radius R 2  centering on a bending center C 2  located on the opposite side of a forming position of the second curved concave surface section  224   d  with respect to the imaginary center line L. The curvature radius R 2  of the second curved concave surface section  224   d  is larger than the curvature radius R 1  of the first curved concave surface section  224   c.  By forming the first curved concave surface section  224   c  and the second curved concave surface section  224   d  in this way, it is possible to prevent ups and downs from being formed in the guide slide contact section  224  and smoothly connect the first curved concave surface section  224   c  and the second curved concave surface section  224   d.    
         [0043]    The guide plate  220  according to a second modification of the second embodiment is explained with reference to  FIG. 9 . 
         [0044]    In the guide plate  220  in the second modification, unlike the first modification, as shown in  FIG. 9 , the bending center C 2  of the second curved concave surface section  224   d  is located on the imaginary center line L. Consequently, when two inner side guides G having different bending radiuses of the shoe surface G 1  are used, even when the guide plate  220  comes into contact with the inner side guides G centering on any one of the curved concave surface sections  224   c  and  224   d , it is possible to maintain a smooth slide contact state of the inner side guides G and the curved concave surface sections  224   c  and  224   d.    
         [0045]    Note that, as in the first modification and the second modification of the second embodiment, when a plurality of curved concave surface sections  224   c  and  224   d  having different curvature radiuses are formed in the guide slide contact section  224 , a slight gap is partially formed between the guide slide contact section  224  and the shoe surface G 1  of the inner side guide G. However, since lubricant is present between the guide slide contact section  224  and the shoe surface G 1  of the inner side guide G, the slight gap does not hinder the smooth slide contact. 
         [0046]    In the embodiments, the chain is explained as the timing chain for the automobile engine. However, the use of the chain of the present invention is not limited to this. The chain may be any chain such as a chain for transmission and a chain for conveyance. 
         [0047]    In the embodiments, the chain of the present invention is explained as a silent chain. However, a specific form of the chain may be any chain formed by alternately arranging in a shifted position by a half pitch in a chain longitudinal direction first plate rows and second plate rows including a plurality of plates arranged in parallel in a chain width direction, with these rows being bendably coupling with one another, and may be, for example, a roller chain and a bush chain. 
         [0048]    In the embodiments, the guide plates are explained as being arranged one each on both the outer sides in the chain width direction of each of the first plate rows. However, specific arrangement, number, and the like of the guide plates may be any arrangement, number, and the like. 
         [0049]    In the embodiments, the example in which the guide slide contact section of the guide plate is configured from only the flat surface section (the first embodiment), the example in which the guide slide contact section is configured from only the single curved concave surface section (the second embodiment), and the example in which the guide slide contact section is configured from the two curved concave surface section having the different curvature radiuses (the first modification and the second modification of the second embodiment) are explained. However, a specific form of the guide slide contact section is not limited to this and may be configured by combining the flat surface section and the curved concave surface section. The numbers of flat surface sections and curved concave surface sections to be combined only have to be arbitrarily determined. 
         [0050]    The configurations of the embodiments and the modifications may be arbitrarily combined to configure a chain. 
         [0051]    The materials of the components of the chain may be any materials such as metal and resin.