JP2008190584A - Pulsar plate mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulsar plate mounting structure wherein a pulsar plate is highly accurately positioned relative to a crank shaft in a well productive manner. <P>SOLUTION: A key groove 14 is formed in a mounting face 10 of a rotary wall portion 9 consisting of a crank arm 3 and a counter weight 4, while a key portion 16 is formed on the pulsar plate P laid on the mounting face 10 for engaging with the key groove 14. The pulsar plate P is fixed to the rotary wall portion 9 with a fixing member 18. The key portion 16 consists of an arched band portion 16a protruded from one end face in an arched shape for engaging with the key groove 14, and a pair of connection portions 16b for integrally connecting both ends of the arched band portion 16a to the pulsar plate P. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the crankshaft for an internal combustion engine, a key groove is formed on an end surface of a rotating wall portion including a crank arm and a counterweight, and a key portion that engages with the key groove is formed on a pulsar plate that is overlaid on the end surface. The present invention relates to an improvement in the mounting structure of the pulsar plate formed and fixed to the rotating wall portion by a fixing member.

Such a pulsar plate mounting structure is already known, as disclosed in Patent Document 1.
Japanese Patent Laid-Open No. 10-331681

  In the conventional pulsar plate mounting structure, the key part is composed of an L-shaped bent part that is cut and raised from the pulsar plate to one end face side. The key part is a cantilever type pulsar. Because it is supported by the plate, it has low rigidity, and it is difficult to increase the positioning accuracy of the pulsar plate with respect to the crankshaft. Moreover, the sharp tip of the key part separated from the pulsar plate is not chamfered. Since finishing is required, the number of processing steps is large and the productivity is not good.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a mounting structure for the pulsar plate, which has high positioning accuracy of the pulsar plate with respect to the crankshaft and has good productivity of the pulsar plate. To do.

  In order to achieve the above object, the present invention provides a key groove on an end face of a rotating wall portion comprising a crank arm and a counterweight of a crankshaft for an internal combustion engine, while the pulsar plate overlaid on the end face has the key In a pulsar plate mounting structure in which a key portion that engages with the groove is formed and this pulsar plate is fixed to the rotating wall portion by a fixing member, the key portion is disposed on one end surface side from the pulsar plate. The first feature is that it is constituted by a bow-like band-shaped portion that protrudes like a bow and engages with the key groove, and a pair of connecting portions that integrally connect both ends of the bow-shaped band-like portion to 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, the fixing member corresponds to the bolt 18, and the fixing portion corresponds to the recess 12 and the boss 15.

  In addition to the first feature, the present invention has a second feature in that the bow-like band-shaped portion is arranged so that its longitudinal direction is along the radial line of the pulsar plate.

  Furthermore, in the present invention, in addition to the first or second feature, the key groove and the bow-shaped band-shaped portion that are engaged with each other are arranged so that their longitudinal directions are along the radial line of the pulsar plate. Three features.

  Furthermore, the present invention is characterized in that, in addition to any of the first to third features, the pulsar plate is provided with long holes that face both side surfaces of the bow-shaped band portion. .

  Furthermore, in addition to any one of the first to fourth features, the present invention provides a plurality of fixing portions of the fixing member to the rotating wall portion of the pulsar plate arranged in the circumferential direction of the pulsar plate. The fifth feature is that the circumferential intervals between at least one fixing portion and the fixing portions at other locations adjacent to both sides of the one fixing portion are different from each other.

  According to the first feature of the present invention, the key portion is projected from the pulsar plate toward the one end surface thereof in a bow shape, and the arch belt portion that engages with the key groove, and both ends of the bow belt portion are connected to the pulsar plate. Since it is composed of a pair of connecting parts that are connected together, the key part is supported by the pulsar plate in a double-supported manner, and thus has high rigidity. Therefore, in cooperation with the key groove, the pulsar plate The positioning accuracy with respect to the crankshaft can be improved. Moreover, since the sharpened tip portion does not exist in the both-sided key portion, finishing processing such as chamfering is unnecessary after press working, and the productivity of the pulsar plate can be increased.

  According to the second feature of the present invention, both side surfaces of the key groove and the bow-shaped band-shaped portion extending in the radial direction of the pulsar plate are in contact with each other over a wide range, and the predetermined circumferential position of the pulsar plate with respect to the crankshaft is determined. Can be held more accurately.

  According to the third feature of the present invention, since the counterweight has a wide end surface overlapping the pulsar plate, the keyway can be easily formed without being overlaid on the end surface. Therefore, the degree of freedom in design is high, the productivity is good, and the collapse of the weight balance due to the build-up of the crankshaft can be prevented.

  According to the fourth feature of the present invention, it is possible to easily perform the press molding of the bow-shaped band portion of the key portion without being resisted by the pulsar plate body.

  According to the fifth feature of the present invention, the mounting position of the pulsar plate with respect to the rotating wall portion of the crankshaft is limited to one place, so that erroneous assembly can be prevented, and therefore the key portion is damaged by erroneous assembly. Can be prevented.

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

  FIG. 1 is a longitudinal side view of a main part of a crankshaft for an internal combustion engine equipped with a pulsar plate mounting structure according to the present invention, FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1, and FIG. FIG.

  1 and 2, the crankshaft C is for a multi-cylinder internal combustion engine, and a plurality of journals 1 supported by a plurality of main bearings of the crankcase and a plurality of connecting rods connected to the large ends. And a plurality of crank arms 3 integrally connecting the adjacent journal 1 and crank pin 2 to each other. Each crank arm 3 includes a crank arm 3 and a crank arm 3 sandwiching the central axis of the journal 1. A counterweight 4 extending in the opposite direction 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, the pulsar plate P has a positioning hole 11 fitted into the annular positioning step 8 at the center thereof, and is fitted into the four recesses 12 so as to surround the positioning hole 11. Four bottom cylindrical bosses 15 are formed, and bolt holes 17 corresponding to the screw holes 13 of the respective recesses 12 are provided at the bottom of each boss 15.

  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. The arcuate belt-like portion 16a is arranged so that the longitudinal direction thereof is along the radial direction of the pulsar plate P in the same manner as the key groove 14, 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 an arcuate belt-shaped portion 16a sandwiched between the long holes 19 is formed. Are formed in a bow shape in the protruding direction of the boss 15, whereby the bow-shaped belt-shaped portion 16 a 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 the boss 15 of the pulsar plate P is engaged with the corresponding recess 12 of the mounting surface 10, while the pulsar plate P is placed on the mounting surface 10. Next, if the bolts 18 inserted into the bolt holes 17 are screwed into the screw holes 13 and tightened, the pulsar plate P can be accurately attached to the fixed position of the mounting surface 10. At that time, the heads 18a of the bolts 18 are accommodated in the corresponding bosses 15 and do not become protrusions from the outer end surface of the pulsar plate P. Therefore, the pulsar plate P is disposed close to the inner wall of the crankcase. enable.

  By the way, the key part 16 of the pulsar plate P has a bow-like band-like part 16a that protrudes from the pulsar plate P toward one end surface and engages with the key groove 14, and both ends of the bow-like band-like part are connected to the pulsar plate P. Since it is comprised by a pair of connection part 16b connected integrally, it can be supported by the pulsar plate P by a double-sided type, and can be provided with high rigidity. Therefore, in cooperation with the key groove, the circumferential positioning accuracy with respect to the mounting surface 10 of the pulsar plate P, that is, the crankshaft C can be increased. 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, since the key groove 14 and the bow-shaped band portion 16a that are fitted to each other are arranged along the radial direction of the pulsar plate P, both side surfaces of the key groove 14 and the bow-shaped band portion 16a along the radial direction of the pulsar plate P are arranged. 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 the collapse of the weight balance due to the build up of the crankshaft C can be prevented.

  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.

  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.

Explanation of symbols

C ··· Crankshaft P ··· Pulsar plates S1 and S2 · Spacing in the circumferential direction 2 ··· Crankpin 3 · · · Crank arm 4 · · · Counterweight 9 · ... Rotating wall 10 ... Mounting surfaces 12, 15 ... Fixed parts (recesses, bosses)
14 ... Key groove 16 ... Key part 16a ... Bow-like band part 16b ... Connection part 18 ... Fixing member (bolt)
19 ... Long hole

Claims (5)

A key groove (14) is formed on an end surface (10) of a rotating wall portion (9) comprising a crank arm (3) and a counterweight (4) of a crankshaft (C) for an internal combustion engine, while the end surface (10) A key portion (16) that engages with the key groove (14) is formed on the pulsar plate (P) that is stacked on the pulsar plate (P), and the pulsar plate (P) is fixed to the rotating wall portion (9) by a fixing member (18). In the pulsar plate mounting structure,
The key portion (16) protrudes from the pulsar plate (P) in the form of a bow on one end face side thereof, and is joined to the key groove (14), and the bow-shaped strip portion (16a). The pulsar plate mounting structure is characterized by comprising a pair of connecting portions (16b) for integrally connecting both ends of the pulsar plate to the pulsar plate (P). The pulsar plate mounting structure according to claim 1,
Attaching the pulsar plate, characterized in that the key groove (14) and the bow-shaped strip (16a) which are engaged with each other are arranged so that their longitudinal directions are along the radial line of the pulsar plate (P). Construction. The pulsar plate mounting structure according to claim 1 or 2,
The pulsar plate mounting structure, wherein the key groove (14) is formed on the end face (10) of the counterweight (4). In the attachment structure of the pulsar plate in any one of Claims 1-3,
The pulsar plate mounting structure, wherein the pulsar plate (P) is provided with elongated holes (19) facing both side surfaces of the bow-shaped strip portion (16a). In the pulsar plate mounting structure according to any one of claims 1 to 4,
Fixing portions (12, 15) of the pulsar plate (P) to the rotating wall portion (9) by the fixing member (18) are a plurality of locations arranged in the circumferential direction of the pulsar plate (P), and at least one Each circumferential interval (S1, S2) between the fixed portion (12, 15) at one location and the fixed portion (12, 15) at another location adjacent to both sides of this one fixed portion (12, 15). Pulsar plate mounting structure, characterized in that they differ from each other.

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