JP2013245583A - Pulsar plate mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress stress concentration in the vicinity of fastening members in a structure where a disk-like pulsar plate is fastened to a mounting surface formed of a crank web and a counter weight and orthogonal to a crank axial line by at least three fastening members.SOLUTION: A pulsar plate 7 includes a plate-like inner circumferential side portion 12 where an insertion hole 11 is formed, and a plate-like outer circumferential side portion 14 continuously provided via an annular step part 13. In the annular step part 13, a protruding part 13b is formed which protrudes to the outside in a radial direction partially in a circumferential direction. The protruding part 13b is provided in a position overlapped in a circumferential direction with at least one (first insertion hole 11a) of two insertion holes 11a, 11b which are provided to be adjacent to both circumferential ends 5b of an end face 5a of the counter weight 5.

Description

  The present invention relates to a pulsar plate mounting structure in which a pulsar plate is fastened by a plurality of fastening members to a mounting surface facing the axial direction of a crankshaft.

  A pulsar plate may be attached to the crankshaft to detect a rotation angle. The pulsar plate is often fastened to the mounting surface facing the axial direction of the crankshaft by a plurality of fastening members, and various inventions have been proposed to alleviate stress concentration around the boss formed in a circular or elliptical shape. (For example, see Patent Documents 1 and 2).

  However, if the pulsar plate is fastened to the boss with an oval or circular recess with a fastening member such as a bolt, the pulsar plate bends at the outer edge of the boss, avoiding stress concentration on the bent part due to flapping deformation. I can't. Therefore, the applicant of the present invention provides the pulsar plate at a flat inner peripheral side portion in which insertion holes for a plurality of fastening members are formed, and at a position offset in the axial direction with respect to the inner peripheral side portion. An invention has been proposed in which an outer peripheral side portion in which a portion is formed and an annular step portion connecting the outer peripheral side portion and the inner peripheral side portion are provided (see Patent Document 3). According to this, since the vibration of the outer peripheral portion can be dispersed by the annular step portion having high rigidity and transmitted to the inner peripheral portion, it is possible to effectively concentrate the stress in the vicinity of the insertion hole of the fastening member. Can be prevented.

JP 2006-153107 A JP 2008-190585 A JP 2010-255694 A

  The invention of Patent Document 1 can increase the rigidity of the pulsar plate by providing an annular step, but as a result of further earnest research by the present inventors, when the insertion hole is adjacent to the annular step, It has been found that stress is concentrated in some insertion holes.

  The present invention has been devised to solve the problems included in the prior art. In the pulsar plate mounting structure in which the pulsar plate is fastened to the end of the crankshaft by at least three fastening members. The object is to suppress stress concentration near the member.

  In order to solve such a problem, according to one aspect of the present invention, a crank web (4) and a counterweight (5) positioned on one shaft end (flange 6) side of the crankshaft (1) are formed. A pulsar plate that fastens a disk-like pulsar plate (7) to at least three fastening members (8) on a mounting surface (1a) that is orthogonal to the crank axis (1X) and faces the one axial end The pulsar plate has a flat plate-like inner peripheral side portion (12) in which an insertion hole (11) of the fastening member is formed, and the shaft end (6) with respect to the inner peripheral side portion. ) Provided at a position offset in the direction, a flat plate-like outer peripheral side portion (14) on which the detected portion (15) is formed, and an annular step portion (13) connecting the outer peripheral side portion and the inner peripheral side portion. ) The mounting surface (end surface 5a) on the unterweight side is substantially larger than the mounting surface (end surface 4a) on the crank web side, and at least two of the insertion holes (11a, 11b) are mounted on the counterweight side. The annular stepped portion is provided at a position corresponding to the surface, and has at least one protruding portion (13b) in which a portion in the circumferential direction protrudes radially outward, and the protruding portion is mounted on the counterweight side. It is set as the structure provided in the position which overlaps with at least 1 of the two insertion holes (11a, 11b) provided so that both the circumferential direction edge parts (5b) of a surface may be adjoined in the circumferential direction.

  If the mounting surfaces are formed on the counter-side mounting surface and the crank web-side mounting surface as described above, flapping deformation of the pulsar plate is suppressed by the mounting surface, so both mountings are not formed. The stress increases between the surfaces, and stress concentrates around the insertion hole that supports this portion on both sides in the circumferential direction. Therefore, as described above, the protrusion is provided by providing a protrusion at a position overlapping with at least one of the two insertion holes provided so as to be adjacent to the circumferential end of the mounting surface on the counterweight side. It is possible to reduce the rigidity of the inner peripheral side portion inside the portion, and to suppress the stress concentration around the insertion hole formed in this portion. If the rigidity of the inner peripheral side portion is lowered, it becomes difficult to maintain the flatness of the pulsar plate, but by providing a protrusion at a position overlapping the mounting surface on the counterweight side having a larger area, the deformation of the pulsar plate Can be suppressed and the flatness can be maintained.

  Further, according to one aspect of the present invention, the protruding portion is provided at a position overlapping the insertion hole (11a) on the side where the stress is more concentrated, of the two insertion holes, in the circumferential direction. Insertion holes (11d, 11d) provided at positions corresponding to the two mounting holes (11a, 11b) and the mounting surface on the crank web side so as to be adjacent to each of the insertion holes (11a, 11b). The circumferential distance (L3, L4) of the portion (9c, 9d) that does not contact the counterweight side mounting surface (5a) and the crank web side mounting surface (4a), Configuration determined based on at least one of the circumferential distances (L1, L2) between the insertion holes (11a, 11b) and the circumferential ends (5b) adjacent to each of the insertion holes (11a, 11b) (9a, 9b) can do.

  The degree of stress concentration in the two insertion holes provided adjacent to the circumferential end of the crank web side mounting surface is at a position corresponding to the crank web side mounting surface adjacent to the insertion hole. The circumferential distance of the portion not contacting the counterweight side mounting surface or the crank web side mounting surface between the provided insertion hole and the circumferential distance from the insertion hole to the adjacent circumferential end Depends on. Therefore, by providing a protrusion at a position that overlaps with the insertion hole on the side where stress is more concentrated, as defined above, stress concentration around the insertion hole on the side where stress is more concentrated is suppressed. can do.

  Moreover, according to one side of this invention, it can be set as the structure which the said annular step part (12) exhibits the egg shape which has one said protrusion part (13b).

  When the protrusion is formed, stress concentration around the insertion hole can be prevented, but the flatness of the pulsar plate tends to decrease, but according to this configuration, stress reduction around the insertion hole where stress concentration becomes the most severe, It is possible to achieve both the flatness of the pulsar plate.

  Further, according to one aspect of the present invention, a key groove (5c) is formed in the counterweight side mounting surface (5a), and the inner peripheral side portion (12) of the pulsar plate is formed in the key groove. A key opening (7b) for forming the key (7a) to be engaged may be formed, and the key opening may be formed in a region where the protruding portion is provided in the circumferential direction.

  According to this configuration, it is possible to reduce the rigidity of the inner peripheral side portion around the insertion hole where stress concentration is likely to be concentrated even by the key opening. Further, by forming the key opening in the region where the protrusion is provided, the key opening can be arranged more radially outward, and the positioning accuracy can be improved.

  Thus, according to this invention, the attachment structure of the pulsar plate which can suppress the stress concentration to the insertion hole vicinity of a fastening member can be provided.

The principal part side view which fractures | ruptures a part of crankshaft and shows the attachment structure of the pulsar plate which concerns on this invention Front view before attaching the pulsar plate of the crankshaft shown in FIG. Front view before attaching the pulsar plate shown in FIG. 1 to the crankshaft IV view in Fig. 1 Action explanatory diagram of the pulsar plate mounting structure shown in FIG. Front view of pulsar plate according to modification

  Hereinafter, an embodiment in which a pulsar plate fastening structure according to the present invention is applied to a V-type engine will be described in detail with reference to the drawings.

  As shown in FIG. 1, a crankshaft 1 of a multi-cylinder engine includes a plurality of journals 2 sandwiched between a cylinder block (not shown) and a crankcase and rotatably supported by a main bearing, and a large connecting rod (not shown). A plurality of crankpins 3 that rotatably support the end portions, a crank web 4 that connects the journal 2 and the crankpin 3, and a counterweight 5 that is connected to the journal 2 on the opposite side of the crank web 4. I have. A flange 6 to which a crank pulley and a flywheel are coupled is formed at the shaft end of the crankshaft 1.

  The crank web 4 and the counterweight 5 located closest to the flange 6 side (shaft end side) form a mounting surface 1a that is orthogonal to the crank axis 1X and faces the flange 6. A disk-shaped pulsar plate 7 for detecting the rotational position and rotational speed of the crankshaft 1 is fastened to the mounting surface 1 a by a plurality of bolts 8.

  As shown in FIG. 2, the counterweight 5 has a generally sector shape extending radially outward from the journal 2, and constitutes an attachment surface 1a, which is an end surface 5a (counterweight 5 side) perpendicular to the crank axis 1X. The mounting surface 1a) is formed on substantially the entire surface. 2 indicates a region where an inner peripheral side portion 12 of the pulsar plate 7 to be described later comes into surface contact, and a broken portion in FIG. 1 indicates a cross section taken along the line II in FIG. ing.

  On the other hand, the crank web 4 positioned closest to the shaft end is an arm that extends radially outward from the journal 2 and holds the crank pin 3, and is formed narrower than the counterweight 5. The crank web 4 has an end face 4a (crank web) on the flange 6 side perpendicular to the crank axis 1X, which is formed in the same plane as the end face 5a of the counterweight 5, by cutting away unnecessary portions of the meat for weight reduction. The four side mounting surfaces 1a) are formed only on the two bosses 4A projecting from both ends in the circumferential direction for fixing the pulsar plate 7 and the shoulders 4B connecting the two bosses 4A.

  Therefore, the end surface 5a of the counterweight 5 (the mounting surface 1a on the counterweight 5 side) and the end surface 4a of the crank web 4 (the mounting surface 1a on the crank web 4 side) formed on the same plane orthogonal to the crank axis 1X The end surface 5 a of the counterweight 5 is substantially larger than the end surface 4 a of the crank web 4.

  The crankshaft 1 is formed with four fastening holes 10 (hereinafter referred to as first to fourth fastening holes 10a to 10d) of bolts 8 for fixing the pulsar plate 7. These four fastening holes 10 are arranged on an imaginary circle 9 (concentric circle) having a radius r that is equidistant from the crank axis 1X, that is, the center thereof coincides with the crank axis 1X. Two of the four fastening holes 10 (first and second fastening holes 10a, 10b) are formed in the counterweight 5, and the remaining two (third and fourth fastening holes 10c, 10d) are cranks. It is formed on the boss portion 4 </ b> A of the web 4.

  The two fastening holes 10a and 10b formed in the counterweight 5 are arranged in close proximity to one of the two circumferential end portions 5b, which are side edges in the circumferential direction of the end surface 5a of the counterweight 5 having a sector shape. Here, the 1st fastening hole 10a is arrange | positioned in the position closer to the circumferential direction edge part 5b rather than the 2nd fastening hole 10b. That is, the circumferential distance L1 of the portion between the first fastening hole 10a on the virtual circle 9 and the circumferential end 5b adjacent thereto (hereinafter referred to as the first backrest portion 9a) is the virtual circle 9. It is smaller than the circumferential distance L2 to the portion between the upper second fastening hole 10b and the circumferential end 5b adjacent thereto (hereinafter referred to as the second backrest 9b) (L1 < L2).

  A positioning keyway 5c is formed on the end surface 5a of the counterweight 5 on the flange 6 side. The key groove 5 c is formed with a constant width so as to extend radially outside the fastening hole 10 in the radial direction.

  As shown in FIGS. 1 and 3, the pulsar plate 7 includes a radially inner inner peripheral portion 12 and a radially outer peripheral portion 14 connected via an annular step portion 13. Four insertion holes 11 for bolts 8 (hereinafter referred to as first to fourth insertion holes 11a to 11d) are formed in the inner peripheral portion 12 at positions corresponding to the fastening holes 10. A large number of protrusions 15 to be detected projecting radially outward are formed on the periphery of the outer peripheral portion 14. The annular step portion 13 connects the inner peripheral portion 12 and the outer peripheral portion 14 over the entire circumference. In a state where the pulsar plate 7 is attached to the crankshaft 1, the inner peripheral portion 12 is orthogonal to the crank axis 1 </ b> X, and the outer peripheral portion 14 is orthogonal to the crank axis 1 </ b> X and is in the flange 6 direction with respect to the inner peripheral portion 12. At a position offset by a distance D (FIG. 1). The pulsar plate 7 is formed by pressing a magnetic metal plate.

  The annular step portion 13 includes an arc-shaped concentric portion 13a centered on the crank axis 1X and a protruding portion 13b that protrudes radially outward from the concentric portion 13a. Here, since only one protrusion 13b is formed and the circumferential extension angle θa of the concentric portion 13a around the crank axis 1X is 180 degrees or more, the annular step portion 13 has a substantially egg shape. Presents. The total of the circumferential extension angle θa around the crank axis 1X of the concentric part 13a and the circumferential extension angle θb around the crank axis 1X of the protruding part 13b is 360 °. The extending angle θb in the circumferential direction around the crank axis 1X of the protrusion 13b is 180 ° or less.

  The protruding portion 13b has a pair of base portions 13c having a larger radius of curvature than the concentric portion 13a and a smaller radius of curvature than the concentric portion 13a, and the distance from the crank axis 1X is the distance between the concentric portion 13a and the base portion 13c. It is comprised from the protrusion part 13d which becomes the largest in it. Here, the annular step portion 13 is axisymmetric, and the extending angle θc in the circumferential direction about the crank axis 1X of the pair of base portions 13c is the same. Further, the extending angle θc in the circumferential direction around the crank axis 1X of each base portion 13c is smaller than the extending angle θd in the circumferential direction around the crank axis 1X of the protruding end 13d.

  The protruding portion 13b and the protruding end portion 13d are disposed at a position overlapping the first insertion hole 11a in the circumferential direction. In addition, one of the proximal ends of the protruding portions 13b extends to a position overlapping the second insertion hole 11b in the circumferential direction.

  Here, the base 13c is formed by a continuous curve that places the center of curvature on the inner side (crank axis 1X side) while changing the radius of curvature, but the center of curvature is outward as shown in FIG. 6A. It may be a form including a curve in the direction of placement. Here, the protruding end portion 13d is configured to have a relatively small radius of curvature over the entire length. However, as shown in FIG. 6A, the protruding end portion 13d has a radius of curvature only at its both ends. The form formed so that the curve smaller than the concentric part 13a may be included may be sufficient.

  Returning to FIG. 3, a key 7 a for positioning by engaging with the key groove 5 c of the counterweight 5 is formed on the inner peripheral side portion 12 of the pulsar plate 7 so as to project. The key 7a is formed into a rectangular piece that protrudes radially outward from the inner peripheral side portion 12 by being thinned at both sides in the circumferential direction and radially outer side to form a key opening 7b. It is cut and raised in the opposite direction (counterweight 5 side) (see FIG. 1). By engaging the key 7a with the key groove 5c, the relative position in the circumferential direction, which is the rotational direction of the pulsar plate 7 with respect to the crankshaft 1, is determined.

  Further, in order to allow the crankshaft 1 to be inserted into the pulsar plate 7, a perfect circular through hole 12 a centering on the crankshaft axis 1 </ b> X is formed at the center of the plurality of protrusions 15 to be detected, and the center of gravity is placed on the crankshaft. In order to coincide with one axis line, an appropriately sized thinning hole 7 d is formed at an appropriate position of the inner peripheral side portion 12.

  As shown in FIGS. 1 and 2, the portion of the journal 2 that is closest to the flange 6 of the crankshaft 1 is connected to the crank web 4 and the counterweight 5, that is, the portion that is connected to the mounting surface 1a of the crankshaft 1 is the crank axis 1X. The outer peripheral surface 1b is formed in a perfect circle shape centering on the outer periphery and having a larger diameter than the flange 6. As shown in FIGS. 1 and 3, the inner peripheral surface of the through hole 12 a formed in the inner peripheral side portion 12 of the pulsar plate 7 is fitted to the outer peripheral surface 1 b of the crankshaft 1, and the inner periphery of the pulsar plate 7 is Inserted with one side surface of the side portion 12 in contact with the mounting surface 1a (5a, 4a) of the crankshaft 1, that is, with the through hole 12a of the pulsar plate 7 fitted in the outer surface 1b of the crankshaft 1 When the four bolts 8 inserted into the holes 11 are fastened to the fastening holes 10, the pulsar plate 7 is fixed to the crank web 4 and the counterweight 5 and assembled in the state shown in FIG. In addition, the oblique line in FIG. 4 has shown the area | region where the crankshaft 1 and the pulsar plate 7 surface-contact like FIG.

  As shown in FIG. 4, among the four insertion holes 11, the second insertion hole 11b located at the upper right in the figure and the fourth insertion hole 11d located at the lower left are at an angle of 180 degrees with respect to the crank axis 1X. Placed in position. That is, the circumferential angle between the first insertion hole 11a and the fourth insertion hole 11d around the crank axis 1X is θ1, and the circumference between the second insertion hole 11b and the first insertion hole 11a around the crank axis 1X. The direction angle is θ2, the circumferential angle between the third insertion hole 11c and the second insertion hole 11b centered on the crank axis 1X is θ3, and the fourth insertion hole 11d and the third insertion hole centered on the crank axis 1X. When the circumferential angle with respect to 11c is θ4, θ1 + θ2 = 180 ° and θ3 + θ4 = 180 °. On the other hand, the first insertion hole 11a and the third insertion hole 11c are both close to the fourth insertion hole 11d with respect to the centers of the second and fourth insertion holes 11b and 11d (at an angular position of 90 degrees from both) in the circumferential direction. They are arranged at offset positions (θ1, θ4 <90 ° <θ2, θ3).

  As described above, the circumferential distance L1 of the first backrest portion 9a on the virtual circle 9 is smaller than the circumferential distance L2 of the second backrest portion 9b on the virtual circle 9 (L1 <L2). The circumferential angle θ1 between the first insertion hole 11a and the fourth insertion hole 11d centered on the axis 1X is greater than the circumferential angle θ3 between the third insertion hole 11c and the second insertion hole 11b centered on the crank axis 1X. Is smaller (θ1 <θ3), the virtual circle between the first insertion hole 11a and the fourth insertion hole 11d provided at a position corresponding to the mounting surface 1a on the crank web 4 side so as to be adjacent to the first insertion hole 11a. 9 is a circumferential direction of a portion (hereinafter referred to as a first opening portion 9c) that does not contact the end surface 5a of the counterweight 5 or the end surface 4a of the crank web 4 (that is, a back support that supports the back side). The distance L3 is adjacent to the second insertion hole 11b. As described above, the counterweight 5 on the imaginary circle 9 and the end surface 4a of the crank web 4 between the third insertion hole 11c provided at the position corresponding to the mounting surface 1a on the crank web 4 side It is shorter than the circumferential distance L4 of the portion that does not contact (hereinafter referred to as the second opening portion 9d) (L3 <L4).

  As shown in FIG. 2, since the key groove 5c is formed at a relatively radially outer position, even if the key 7a is arranged at a position where it does not overlap the counterweight 5, the pulsar plate 7 is not counterweighted. 5, but as described above, the at least one insertion hole 11 is offset in the circumferential direction with respect to the position where all the insertion holes 11 are evenly arranged. All bolts 8 cannot be fastened unless they are arranged at appropriate angular positions.

  In addition, the first insertion hole 11a and the third insertion hole 11c are angular positions having different offset amounts from the positions where they are evenly arranged (angle positions of 90 degrees from the second and fourth insertion holes 11b and 11d), More specifically, they are arranged at an angular position where θ2 <θ3. That is, the four circumferential angles θ1 to θ4 have a relationship of θ4 <θ1 <θ2 <θ3. Thereby, even when the pulsar plate 7 is to be assembled upside down, the bolts 8 cannot be inserted into all the fastening holes 10.

  However, in the case where the front and back sides are reversed, the outer peripheral portion 14 of the pulsar plate 7 is offset in the crankshaft direction with respect to the inner peripheral portion 12, and the end face 5a of the counterweight 5 as shown in FIGS. Is also extended to a position corresponding to the outer peripheral portion 14 to prevent erroneous assembly.

  The rotation sensor (not shown) facing the detected protrusion 15 of the pulsar plate 7 has a built-in Hall element and magnet in its detection part, and the detected protrusion 15 approaches and separates as the pulsar plate 7 rotates. Is converted into an electrical signal by the Hall element, and the rotational position and rotational speed of the crankshaft 1 are detected based on the electrical signal.

  Next, the operation of the embodiment of the present invention having the above configuration will be described. When the plate-like pulsar plate 7 is rotated together with the crankshaft 1, a pair of the crankpin 3 is sandwiched due to a combustion load from a connecting rod applied to the crankpin 3 as shown in FIGS. 5 (A) and 5 (B). When the crankshaft 1 is bent and deformed to open and close the counterweight 5, the pulsar plate 7 flutters and deforms in the resonance region as shown in FIG. 5C. At this time, the outer peripheral portion 14 is deformed to the crank axis 1X. There is a possibility that the vibration that undulates in the direction may cause stress concentration near the fastening portion of the pulsar plate 7 by the bolt 8 and may decrease the detection accuracy of the rotational position and rotational speed of the pulsar plate 7 by the rotation sensor. FIG. 5 exaggerates the deformation for easy understanding.

  However, the pulsar plate 7 of the present embodiment has high rigidity because the outer peripheral side portion 14 on which the detected protrusion 15 is formed is connected to the inner peripheral side portion 12 via the annular step portion 13 extending over the entire circumference. Transmission of the vibration of the outer peripheral side portion 14 to the inner peripheral side portion 12 is suppressed by the annular step portion 13, and stress concentration in the vicinity of the insertion hole 11 of the inner peripheral side portion 12 is effectively prevented.

  In addition, since the annular step portion 13 is provided over the entire circumference, the rigidity of the outer peripheral side portion 14 is increased and vibration during rotation is prevented. Therefore, the rotation position and the rotation speed of the crankshaft 1 are detected by the rotation sensor. Accuracy is improved. In particular, since the annular step 13 is formed over the entire circumference, the rigidity of the outer peripheral portion 14 is effectively improved.

  On the other hand, although vibration is suppressed by the annular step portion 13, stress concentrates around the fastening portion at a position where flapping deformation is likely to occur. In the present embodiment, since the inner peripheral portion 12 is in surface contact with the mounting surface 1a (5a, 4a) of the crankshaft 1, it is between the first and second insertion holes 11a, 11b in FIG. Flapping deformation hardly occurs between the insertion holes 11c and 11d, and flapping deformation easily occurs between the second and third insertion holes 11b and 11c and between the first and fourth insertion holes 11a and 11d.

  Therefore, in the present embodiment, of the first and second insertion holes 11a and 11b provided so as to be adjacent to both circumferential ends 5b of the end surface 5a of the counterweight 5, the first insertion on the side where stress is more concentrated. The protruding portion 13b of the annular step portion 13 is positioned at a position overlapping the hole 11a in the circumferential direction.

  Here, the stress concentration around the insertion hole 11 largely depends on the following two factors. In this embodiment, the stress is concentrated in the first insertion hole 11a rather than the second insertion hole 11b due to the relationship. become. The first factor is the circumferential distances L3 and L4 of the first and second opening portions 9c and 9d. The second factor is the circumferential distances L1 and L2 of the first and second backrest portions 9a and 9b.

  That is, as the circumferential distances L3 and L4 of the opening portions 9c and 9d that are not backed by the crank web 4 and the counterweight 5 on the virtual circle 9 are larger, the stress concentration around the insertion hole 11 located at one end thereof is larger. (Acts positively on stress concentration) On the other hand, the greater the circumferential distances L1 and L2 of the backrest portions 9a and 9b on the virtual circle 9, the smaller the stress concentration on the insertion hole 11 (minus the stress concentration). Act on).

  In the present embodiment, when the circumferential distances L3 and L4 of the first and second opening portions 9c and 9d on the virtual circle 9 are compared, the second opening portion 9d is larger than the first opening portion 9c (L4). > L3), the stress tends to concentrate on the second insertion hole 11b, and when the circumferential distances L1 and L2 of the first and second backrest portions 9a and 9b on the virtual circle 9 are compared, the first backrest portion Since 9a is smaller than the second backrest portion 9b (L1 <L2), stress tends to concentrate on the first insertion hole 11a.

  At this time, the influence on the stress concentration is greater in the circumferential direction of the open portions 9c and 9d without the backrest than due to the difference in the circumferential distances L1 and L2 of the backrest portions 9a and 9b with the backrest up to the bolt 8. The difference due to the difference between the distances L3 and L4 is larger. Therefore, when L1 <L2 (stress concentration on the first insertion hole 11a side) and L3 <L4 (stress concentration on the second insertion hole 11b side) as in the present embodiment, the difference of L1 <L2 is much greater. If not, stress concentrates on the L4 side (second insertion hole 11b) due to the effect of L3 <L4. On the other hand, in the present embodiment, L3 (53 °) <L4 (55 °), but since the difference is only 2 °, the influence due to the difference between the open portions 9c and 9d without backrest is not so great. , L1 (20 °) <L2 (35 °) has a large influence, so that stress tends to concentrate on the first insertion hole 11a side.

  As described above, by providing the protruding portion 13b of the annular step portion 13 at a position overlapping the first insertion hole 11a in the circumferential direction, the rigidity of the inner peripheral side portion 12 inside the protruding portion 13b is reduced, and the stress Is dispersed, the stress is prevented from concentrating around the first insertion hole 11a formed in this portion. When the rigidity of the inner peripheral portion 12 is lowered, the flatness of the pulsar plate 7 is difficult to be maintained, but the protruding portion 13b is provided at a position overlapping the mounting surface 1a on the counterweight 5 side having a larger area. The flatness can be maintained by suppressing the deformation of the pulsar plate 7.

  Further, by forming the protruding portion 13b in the annular step portion 13, stress concentration around the inner insertion hole 11 can be prevented, while the flatness of the pulsar plate 7 tends to decrease. Since the annular step portion 13 has an egg shape having one protrusion 13b, it is possible to achieve both reduction of stress around the first insertion hole 11a where stress concentration is most severe and securing flatness of the pulsar plate 7. Figured.

  Further, the keyway 5c is formed in the end surface 5a of the counterweight 5 in the crank axis 1X direction, and the key opening 7b is formed in the inner peripheral side portion 12 of the region where the protruding portion 13b is provided in the circumferential direction. Also by the key opening 7b, the rigidity of the inner peripheral side portion 12 is reduced, and the stress around the first insertion hole 11a where stress tends to concentrate is reduced. In addition, the key opening 7b is formed in a region where the protruding portion 13b is provided in the circumferential direction, so that the key opening 7b can be arranged more radially outward, and the positioning accuracy of the pulsar plate 7 is improved.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified. For example, in the above embodiment, the mounting structure of the pulsar plate 7 according to the present invention is applied to a V-type multi-cylinder engine. However, it can be applied to an in-line multi-cylinder engine, a horizontally opposed engine, and a single-cylinder engine. is there. Moreover, in the said embodiment, although the one protrusion part 13b is formed in the cyclic | annular step part 13, as shown, for example to FIG. 6 (B), you may form multiple protrusion parts 13b. In this case, at least a part of the protrusion 13b in the circumferential direction, preferably the protrusion 13d may be disposed so as to contact the end surface 5a of the counterweight 5, and the adjacent protrusion 13b is continuous. It is also possible. Further, the number of bolts 8 for fastening the pulsar plate 7 to the crankshaft 1 is not limited to four. In addition, the specific configuration, quantity, and arrangement of each member and part can be changed as appropriate without departing from the spirit of the present invention. On the other hand, all the components of the mounting structure of the pulsar plate 7 according to the present invention shown in the above embodiment are not necessarily essential, and can be appropriately selected.

1 Crankshaft 1X Crank axis 1a Mounting surface 4 Crank web 4a End surface (Mounting surface)
5 Counterweight 5a End surface (mounting surface)
5b Circumferential end 5c Keyway 6 Flange (shaft end)
7 Pulsar plate 7a Key 7b Key opening 8 Bolt (fastening member)
DESCRIPTION OF SYMBOLS 11 Insertion hole 12 Inner peripheral part 13 Annular step part 13a Concentric part 13b Protrusion part 14 Outer peripheral part 15 Detected protrusion

Claims (4)

At least three disk-shaped pulsar plates are fastened to a mounting surface formed by a crank web and a counterweight located on one end of the crankshaft and perpendicular to the crankshaft axis and facing the one end A pulsar plate fastening structure fastened by a member,
The pulsar plate is provided in a flat plate-like inner peripheral side portion in which the insertion hole of the fastening member is formed, and a position offset in the axial direction with respect to the inner peripheral side portion, and a detected portion is formed. A flat plate-like outer peripheral side portion, and an annular step portion connecting the outer peripheral side portion and the inner peripheral side portion,
The counterweight side mounting surface is substantially larger than the crank web side mounting surface,
At least two of the insertion holes are provided at positions corresponding to the mounting surface on the counterweight side,
The annular stepped portion has at least one protruding portion in which a portion in the circumferential direction protrudes radially outward;
The protruding portion is provided at a position overlapping with at least one of two insertion holes provided so as to be adjacent to both end portions in the circumferential direction of the mounting surface on the counterweight side. Pulsar plate fastening structure.   The protrusion is provided at a position overlapping with the insertion hole on the side where the stress is more concentrated, in the circumferential direction, of the two insertion holes, and the insertion hole on the side where the stress is more concentrated is the two insertion holes. The counterweight side mounting surface and the crank web side mounting surface are not in contact with the insertion holes provided at positions corresponding to the crank web side mounting surface so as to be adjacent to each of them. It is defined based on at least one of the circumferential distance of a part and the circumferential distance between the both insertion holes and the circumferential end adjacent to each of the insertion holes. Fastening structure of the described pulsar plate.   The pulsar plate fastening structure according to claim 1, wherein the annular step portion has an egg shape having one protruding portion. A keyway is formed on the mounting surface on the counterweight side,
A key opening for forming a key that engages with the key groove is formed in the inner peripheral side portion of the pulsar plate,
4. The pulsar plate fastening structure according to claim 3, wherein the key opening is formed in a region where the protrusion is provided in a circumferential direction. 5.

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