JP2008190585A - Pulsar plate mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulsar plate mounting structure having improved durability around bosses by widely dispersing concentrating stress generated at the peripheral edges of the bosses of a pulsar plate on the side of facing the plate in the peripheral direction during the vibration of the pulsar plate. <P>SOLUTION: In the pulsar plate mounting structure, a plurality of recessed portions 12 are formed in an end face 10 of a rotary wall portion 9 of an internal combustion engine crank shaft C, consisting of a crank arm 3 and a counter weight 4, so as to be lined in the peripheral direction, while the plurality of bottomed cylindrical bosses 15 are formed on the pulsar plate P laid on the end face 10 so as to be stored in the plurality of recessed portions 12. The bosses 15 are fixed to the pulsar plate P with fixing members 18. A cylindrical portion 15a of each boss 15 is formed in a deformed cylindrical shape with its minor diameter D1 toward a peripheral direction A of the pulsar plate P and its major diameter D2 toward a radial direction B of the pulsar plate P. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  According to the present invention, a plurality of concave portions arranged in the circumferential direction are formed on an end surface of a rotating wall portion including a crank arm and a counterweight of an internal combustion engine crankshaft, while the plurality of pulsar plates overlapped with the end surface. The present invention relates to an improvement in a pulsar plate mounting structure in which a plurality of bottomed cylindrical bosses accommodated in recesses are formed and these bosses are fixed to a pulsar plate by a fixing member.

Such a pulsar plate mounting structure is already known, as disclosed in Patent Document 1.
JP 11-13736 A

  In such a pulsar plate mounting structure, a plurality of recesses arranged in the circumferential direction are formed on the end surface of the rotating wall portion of the crankshaft, while the pulsar plate stacked on the end surface is accommodated in the plurality of recesses. Forming a plurality of bottomed cylindrical bosses, and fixing these bosses to the pulsar plate with a fixing member is because the bottomed cylindrical boss has high rigidity, so that the fixing force of the pulsar plate to the rotating wall is reduced. Can be increased.

  However, since the pulsar plate is relatively thin, the pulsar plate may vibrate during operation of the engine, and the vibration generates concentrated stress at the peripheral portion of the highly rigid boss.

  By the way, since the vibration of the pulsar plate is particularly intense at the plate-like portion between the plurality of bosses, the concentrated stress generated at the peripheral portion of the boss is particularly on the side of the peripheral portion facing the circumferential direction of the pulsar plate. The greatness was investigated by the present inventors.

  The present invention has been made on the basis of such investigations. When the pulsar plate vibrates, the concentrated stress generated on the side of the boss of the pulsar plate facing the circumferential direction of the pulsar plate is widely dispersed. An object of the present invention is to provide a simple structure for attaching a pulsar plate that can contribute to improvement of durability around the boss.

  In order to achieve the above object, the present invention forms a plurality of recesses arranged in the circumferential direction on the end surface of a rotating wall portion comprising a crank arm and a counterweight of an internal combustion engine crankshaft, while overlapping the end surface. In the pulsar plate mounting structure, a plurality of bottomed cylindrical bosses accommodated in the plurality of recesses are formed on the pulsar plate, and the bosses are fixed to the pulsar plate with fixing members. The first feature is that the shape portion is formed in a deformed cylindrical shape in which the short diameter is directed in the circumferential direction of the pulsar plate and the long diameter is directed in the radial direction of the pulsar plate.

  The end surface of the rotating wall portion corresponds to the mounting surface 10 in the embodiment of the present invention described later, and the fixing member corresponds to the bolt 18.

  In addition to the first feature, the present invention has a second feature that the cylindrical portion of the boss is formed in an elliptical cylindrical shape.

  Furthermore, in addition to the first or second feature, the present invention has a third feature that the curvature of the bent portion connected to both ends of the cylindrical portion of the boss is set smaller on the short diameter side than on the long diameter side.

  According to the first feature of the present invention, the cylindrical portion of the boss of the pulsar plate is formed in a deformed cylindrical shape with the short diameter directed in the circumferential direction of the pulsar plate and the long diameter directed in the radial direction of the pulsar plate. During engine operation, if vibration occurs in the plate-like part between adjacent bosses of the pulsar plate, the vibration is transmitted to the peripheral part of the deformed cylindrical part in the range of the long diameter, and is therefore attributed to the vibration. The stress to be distributed is widely dispersed in the peripheral portion of the irregular cylindrical portion within the range of the major axis, and durability around each boss can be achieved.

  According to the second feature of the present invention, since the change in the curvature of the elliptical cylindrical portion of the boss of the pulsar plate is extremely smooth, the stress distribution is also ideal, and the durability around each boss is effectively enhanced. be able to.

  According to the third feature of the present invention, the curvature of the bent portion connected to both ends of the cylindrical portion of the boss of the pulsar plate is set to be smaller on the short diameter side than on the long diameter side. In particular, the concentrated stress generated on the short diameter side of the boss, that is, the peripheral edge of the pulsar plate in the circumferential direction B side, can be more widely dispersed during vibration at the bosses, and the durability around each boss 15 can be further enhanced. Can do.

  Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 is a longitudinal sectional side view of a main part of a crankshaft for an internal combustion engine equipped with a pulsar plate mounting structure according to a first embodiment of the present invention, FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1, and FIG. 4 is an enlarged sectional view taken along line 3-3, FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 2, FIG. 5 is an enlarged view corresponding to the main part of FIG. FIG. 6 is a view corresponding to FIG. 3 showing a third embodiment of the present invention.

  First, the description starts with the description of the first embodiment of the present invention shown in FIGS. 1 and 2, the crankshaft C is used for a multi-cylinder internal combustion engine, and a plurality of journals supported by a plurality of main bearings of a crankcase and a plurality of cranks connected to the large ends of a plurality of connecting rods. A plurality of crank arms 3 integrally connecting the pin 2 and the adjacent journal 1 and crank pin 2 are provided. Each crank arm 3 has a direction opposite to the crank arm 3 across the central axis of the journal 1. A counterweight 4 extending in a straight line is integrally provided. At one end of the crankshaft C, a flange 5 to which a driven member such as a crank pulley or a flywheel is bolted is formed.

  As shown in FIG. 2, the crank arm 3 is formed narrow in the circumferential direction, and the counterweight 4 is formed wide in the circumferential direction, and the crank wall 3 and the counterweight 4 form a rotating wall portion 9. Composed. A pulsar plate P formed by press-molding a magnetic metal plate is attached to the outermost rotating wall 9 on the flange 5 side. The pulsar plate P has a large number of protrusions 7 arranged on its outer periphery, and a rotation sensor (not shown) installed on the engine body is disposed opposite the outer peripheral surface.

  Thus, the rotation sensor incorporates a Hall element and a magnet in its detection part. When the pulsar plate P rotates with the crankshaft C, the magnetic fluctuation in the rotation sensor is converted into an electrical signal by the Hall element. By converting and calculating it, the rotational position, rotational speed, rotational acceleration, etc. of the crankshaft C can be known.

  Now, a structure for attaching the pulsar plate P to the rotating wall portion 9 of the crankshaft C will be described with reference to FIGS.

  As shown in FIG. 1, on the outer end surface of the outermost rotating wall portion 9, an annular positioning step portion 8 having a diameter larger than the flange 5 and concentric with the journal 1, and a crank arm 3 from the root of the annular positioning step portion 8. And the attachment surface 10 which spreads in the radial direction toward the counterweight 4 is formed. On both sides of the outer surface of the crank arm 3 along the rotation direction, slopes 3a for reducing the thickness of the crank arm 3 are formed. For this reason, the mounting surface 10 is on the counterweight 4 side on the crank arm 3 side. It is narrower than that.

  As shown in FIGS. 1 and 2, the mounting surface 10 is provided with a plurality (four in the illustrated example) of recesses 12 having the same shape (circular in the illustrated example) arranged in the circumferential direction. At this time, the four recesses 12 are arranged so that the circumferential intervals S1 and S2 between at least one recess 12 and the other recesses 12 adjacent to both sides of the one recess 12 are different from each other. . In the case of the illustrated example, the four recesses 12 are arranged on the virtual circle 20 concentric with the journal 1 so that the circumferential intervals between the adjacent recesses 12 are all different. A screw hole 13 is formed in each central portion of the four recesses 12. Further, a key groove 14 is formed at a predetermined location on the mounting surface 10 on the counterweight 4 side. At that time, the key groove 14 is arranged so that the longitudinal direction thereof follows the radius line of the pulsar plate P.

  On the other hand, in the pulsar plate P, a positioning hole 11 fitted into the annular positioning step portion 8 is accommodated in the four concave portions 12 so as to surround the positioning hole 11 in the center portion thereof. A number of bosses 15 are formed. Each boss 15 has a bottomed elliptical cylindrical shape, and an elliptical cylindrical portion 15a directs the short diameter D1 in the circumferential direction A of the pulsar plate P and the long diameter D2 in the radial direction B of the pulsar plate P. The bottom of each boss 15 is provided with a bolt hole 17 corresponding to the screw hole 13 of each recess 12.

  Further, a key portion 16 that engages with the key groove 14 is integrally formed on the pulsar plate P. The key portion 16 includes an arched belt-like portion 16a that protrudes from the pulsar plate P toward one end surface thereof, and a pair of connecting portions 16b that integrally connect both ends of the arched belt-like portion 16a to the pulsar plate P. In the same manner as the key groove 14, the bow-like band-shaped portion 16 a is arranged so that its longitudinal direction is along the radial direction of the pulsar plate P, and is fitted between both inner side surfaces of the key groove 14. (See FIG. 3). When this bow-like band-like portion 16a is closely fitted in the key groove 14, all the bosses 15 of the pulsar plate P are loosely fitted in all the concave portions 12 of the mounting surface 10.

  When the key portion 16 is formed, first, a pair of long holes 19 (see FIG. 2) are punched into the pulsar plate P so that both side surfaces of the key portion 16 face each other, and then a belt-like portion 16a sandwiched between the long holes 19 is formed. In this way, the boss 15 is press-formed in the form of a bow so that the bow-shaped strip 16a can be easily formed without being resisted by the pulsar plate body.

  Next, the operation of this embodiment will be described.

  In attaching the pulsar plate P to the attachment surface 10 of the rotating wall 9, first, the positioning hole 11 of the pulsar plate P is fitted into the annular positioning step 8 of the rotating wall 9 from the flange 5 side of the crankshaft C. . At this time, the key portion 16 of the pulsar plate P is engaged with the key groove 14 of the mounting surface 10, and each boss 15 of the pulsar plate P is inserted into the corresponding recess 12 of the mounting surface 10, while the pulsar plate P On the mounting surface 10. Next, when the bolts 18 inserted into the bolt holes 17 are screwed into the screw holes 13 and tightened, the bosses 15 are fastened to the bottom surfaces of the corresponding recesses 12, and the pulsar plate P is accurately placed at a fixed position on the mounting surface 10. Can be attached. In particular, since each boss 15 having a bottomed cylindrical shape has high rigidity, the fixing strength of the pulsar plate P to the mounting surface 10 can be increased.

  However, since the pulsar plate P made of press is relatively thin, the plate-like portion between the adjacent bosses 15 may vibrate vigorously during torque fluctuation of the crankshaft C during engine operation. According to the vibration of the cylindrical portion, stress is concentrated on the peripheral portion of the cylindrical portion 15a of each boss 15, but the cylindrical portion 15a of each boss 15 has a short diameter D1 in the circumferential direction A of the pulsar plate P. Therefore, the vibration of the plate-like portion between the bosses 15 of the pulsar plate P is in the range of the long diameter D2, so that the long diameter D2 is formed in the radial direction B of the pulsar plate P. Therefore, the stress caused by the vibration is widely dispersed in the peripheral edge of the elliptical cylindrical portion 15a in the range of the major axis D2, and the durability around each boss 15 is improved. be able to. In particular, since the change in the curvature of the ellipse of the elliptic cylindrical portion 15a is very smooth, the stress distribution is also ideal, and the durability around each boss 15 can be effectively enhanced.

  The heads 18a of the bolts 18 accommodated in the recesses 12 are accommodated in the corresponding bosses 15 and do not project from the outer end surface of the pulsar plate P. Allows close placement.

  Further, the key portion 16 of the pulsar plate P projects from the pulsar plate P toward the one end surface thereof in a bow shape, and a bow-shaped strip portion 16a that engages with the key groove 14 and both ends of the bow-shaped strip portion are integrated with the pulsar plate P. And a pair of connecting portions 16b that are connected to each other, are supported by the pulsar plate P in a double-supported manner, and can have high rigidity. Therefore, in cooperation with the keyway, the mounting surface 10 of the pulsar plate P That is, the circumferential positioning accuracy with respect to the crankshaft C can be improved. Moreover, since the sharpened tip portion does not exist in the both-sided key portion 16, finishing processing such as chamfering is unnecessary after pressing, and the productivity of the pulsar plate P can be increased.

  In particular, the key groove 14 and the bow-like band-shaped portion 16a that are fitted to each other are arranged along the radial direction of the pulsar plate P. Therefore, both side surfaces of the key groove 14 and the bow-shaped band-shaped portion 16a along the radial direction of the pulsar plate P Are in contact with each other over a wide range, and the predetermined circumferential position of the pulsar plate P with respect to the crankshaft C can be held more accurately.

  As described above, the mounting surface 10 is wider on the counterweight 4 side than the crank arm 3 side. Therefore, when the key groove 14 is formed on the mounting surface 10 on the counterweight 4 side, the formation position is selected in a wide range. This increases the degree of freedom in design and is advantageous in positioning the pulsar plate P. In addition, when the key groove 14 is formed, it is not necessary to build up the mounting surface 10, so that the productivity is good and it is possible to prevent the weight balance from being lost due to the build up of the crankshaft C.

  Furthermore, the fixing portions of the pulsar plate P and the rotating wall portion 9 by the bolts 18, that is, the recesses 12 and the bosses 15 are provided at a plurality of locations aligned in the circumferential direction of the pulsar plate P, and at least one fixing portion 12, 15, Since the circumferential distances S1 and S2 between the fixing portions 12 and 15 adjacent to both sides of the one fixing portion 12 and 15 are different from each other, the pulser for the rotating wall portion 9 is arranged. Since the mounting position of the plate P is limited to one place, it is possible to prevent erroneous assembly, and thus it is possible to prevent damage to the key portion 16 due to erroneous assembly.

  Next, a second embodiment of the present invention shown in FIG. 5 will be described.

  In the second embodiment, the cylindrical portion 15a of the boss 15 of the pulsar plate P is opposed to the pair of arcuate wall portions 22 facing each other with an interval corresponding to the long diameter D2 and the space corresponding to the short diameter D1. A pair of straight wall portions 23 are continuously connected to form an oval cross section. At this time, the cylindrical portion 15a of the boss 15 is arranged so that the short diameter D1 is directed in the circumferential direction A of the pulsar plate P and the long diameter D2 is directed in the radial direction B of the pulsar plate P, as in the previous embodiment. The Since other configurations are the same as those of the previous embodiment, portions corresponding to those of the previous embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Next, a third embodiment of the present invention shown in FIG. 6 will be described.

  In the third embodiment, the bent portion connected to both ends of the elliptic cylindrical portion 15a of the boss 15 of the pulsar plate P is formed so that the curvature is smaller on the short diameter D1 side than on the long diameter D2 side (see FIG. 4). The Since other configurations are the same as those of the first embodiment, the same reference numerals are given to the portions corresponding to those of the first embodiment in FIG.

  According to this embodiment, when the pulsar plate P vibrates vigorously at the plate-like portion between the adjacent bosses 15, the pulsar plate P is generated particularly at the short diameter D1 side of the boss 15, that is, the peripheral portion on the pulsar plate P circumferential direction B side. The concentrated stress can be more widely dispersed, and the durability around each boss 15 can be further enhanced.

  Also according to the second embodiment, substantially the same effect as the previous embodiment can be exhibited.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, at least two fixing portions of the pulsar plate P and the rotating wall portion 9 by the bolt 18 may be provided. In the case of only two locations, if the circumferential intervals on both sides of the two fixing portions are different, an error may occur. Assembly can be prevented.

The principal part longitudinal cross-sectional side view of the crankshaft for internal combustion engines provided with the attachment structure of the pulsar plate of this invention. FIG. FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 2. FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. The enlarged view corresponding to the principal part of FIG. 2 which shows 2nd Example of this invention. FIG. 4 is a view corresponding to FIG. 3 showing a third embodiment of the present invention.

Explanation of symbols

A ... Circumferential direction of the pulsar plate B ... Radial direction of the pulsar plate C ... Crankshaft D1 ... Short diameter D2 ... Long diameter P ... Pulsar plate 2 ... Crank pin 3 ... Crank arm 4 ... Counter weight 9 ... Rotating wall 10 ... Mounting surface 12 ... Recess 15 ... Boss 15a ... Cylindrical part 15b ... Bottom 18 ... Fixing member (bolt)

Claims (3)

A plurality of recesses (12) arranged in the circumferential direction are formed on the end surface (10) of the rotating wall portion (9) comprising the crank arm (3) and the counterweight (4) of the crankshaft (C) for the internal combustion engine. On the other hand, a plurality of bottomed cylindrical bosses (15) accommodated in the plurality of recesses (12) are formed on the pulsar plate (P) stacked on the end face (10), and these bosses (15) are connected to the pulsar. In the pulsar plate mounting structure, which is fixed to the plate (P) by the fixing member (18),
The cylindrical portion (15a) of the boss (15) is oriented with the short diameter (D1) in the circumferential direction (A) of the pulsar plate (P) and the long diameter (D2) in the radial direction (B) of the pulsar plate (P). Pulsar plate mounting structure, characterized in that it is formed in a deformed cylindrical shape facing toward The pulsar plate mounting structure according to claim 1,
A pulsar plate mounting structure, wherein the cylindrical portion (15a) of the boss (15) is formed in an elliptical cylindrical shape. The pulsar plate mounting structure according to claim 1 or 2,
A structure for attaching a pulsar plate, characterized in that the curvature of the bent portion connected to both ends of the cylindrical portion (15a) of the boss (15) is set smaller on the short diameter (D1) side than on the long diameter (D2) side.

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