JP7242359B2 - Crank gear mounting structure for internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ring gear mounting structure and a crank gear mounting structure for an internal combustion engine, which perform power transmission in connection with a power transmission device from a rotating shaft including, for example, a crankshaft of an internal combustion engine to a camshaft.

Conventionally, in Patent Document 1, as a steam turbine generator, a half-split type ring gear is attached to a rotating shaft to form a ring-shaped gear, which is fixed with a reamer bolt or the like. A ring gear mounting structure has been proposed in which a shim member is interposed and shrink-fitted.
In an internal combustion engine, for example, the following crank gear mounting structure has been proposed as a mechanism for mounting a crank gear divided into two parts on a crank shaft and transmitting power to a cam gear provided on a cam shaft.

8 and 9 show a first cotter-type crank gear mounting structure used for marine engines and the like. Although not shown in these figures, the crankshaft 100 extends forward and is integrated with the crank portion as shown in FIG. 3, which will be described later. In this mounting structure, a crankshaft 100 is combined with a crank gear 101 that is divided into two halves, and a gap is provided between the divided surfaces of the crank gear 101 . The crank gear 101 is pressed against the crank shaft 100 by shrink-fitting the cotter 102 to the connecting portion of the half-split crank gear 101 and fixing it with a fastening bolt 103 .
As a result, the crank gear 101 can transmit power by the frictional force between the inner peripheral surface of the crank gear 101 and the outer peripheral surface of the crankshaft 100 . The crank gear 101 is connected to a cam gear provided on a cam shaft via an idle gear (not shown) or a timing belt to transmit power. The timing of the rotation of the crankshaft 100 due to the explosion in the cylinder and the opening and closing of the intake and exhaust valves by the camshaft are matched.

It is preferable that the inner peripheral surface of the crank gear 101 evenly contacts the outer peripheral surface of the crankshaft 100 by attaching the cotter 102. The inner peripheral surface of crank gear 101 does not evenly contact the outer peripheral surface of crankshaft 100 . When it is necessary to transmit high torque by, for example, increasing the fuel injection pressure, fretting wear may occur between the inner peripheral surface of the crank gear 101 and the outer peripheral surface of the crankshaft 100, resulting in damage. There is

In the second crank gear mounting structure shown in FIGS. 10 to 12, the two-part crank gear 101 has flanges 101a on both sides in the longitudinal direction of the crankshaft 100, and the flanges 101a on both sides are tightened by a pair of bands 105. Thus, the crank gear 101 is pressed against the crankshaft 100 . Since the pair of bands 105 are in contact with each other and tightened with bolts and nuts, the outer peripheral surface of the crankshaft 100 and the inner peripheral surface of the crank gear 101 are in uniform contact over the entire circumference, and the first crank gear is mounted. Suitable for transmission of high torque rather than structure.
In this mounting structure, a shim 106 is attached to the dividing surface of the half-split crank gear 101 to adjust the matagi tooth thickness at the dividing position of the crank gear 101 . However, in this mounting structure, the work of mounting the shim 106 and the band 105 is complicated, and the work of adjusting the matagi tooth thickness is difficult, resulting in a problem of requiring an extremely large number of man-hours.

Next, in the third crank gear mounting structure shown in FIGS. 13 to 15, a crank gear 101 split in half is attached to a ring-shaped gear flange 108 integrally cut out from a crankshaft 100. , and is fixed to the crank gear 101 by tightening a fixing bolt 109 through an insertion hole formed in the gear flange 108 . As a result, power can be transmitted to a camshaft (not shown) by the frictional force between the gear flange 108 and the crank gear 101 due to the tightening force of the fixing bolt 109 .
In this mounting structure, since the crank gear 101 is mounted with the fixing bolt 109, the contact surface pressure between the side surfaces of the crank gear 101 and the gear flange 108 becomes high and uniform, and high transmission torque can be obtained. The crank gear 101 is attached to the outer peripheral surface of the gear flange 108 with a spigot construction (see FIG. 14). Reamed bolts 109a are used as fixing bolts 109 for four bolt holes in the vicinity of the divided portions of the crank gear 101 which is divided into halves.

Japanese Patent Publication No. 4-47252

However, in the third crank gear mounting structure described above, when machining the bolt holes in the gear flange 108, as shown in FIG. Since there is an arm, it cannot be processed from that side. Therefore, a machining tool such as a drill and a reamer is inserted through the bolt hole 110a of the output flange 110 formed on the other side of the crankshaft 100 to machine the gear flange 108 with the bolt hole 108a.

In this case, the P.V. C. D. (pitch circle diameter) is the P.D. C. D. and the bolt hole diameter, and the outer diameter of the crank gear 101 is also increased compared to the first and second crank gear mounting structures described above. It should be noted that the P.V. of the bolt hole 110a C. D. of the bolt hole 108a of the gear flange 108 is restricted by ship classification rules. C. D. is similarly restricted and cannot be smaller than a certain amount.
Along with this, it is necessary to increase the diameter of the cam gear provided on the camshaft, or to make the idle gear two-stage, which leads to an increase in cost. In addition, since the bolt holes 108a for the reamer bolts of the gear flange 108 require machining with a jig, a setup process is required and the machining cannot be unmanned, which also causes an increase in cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a ring gear mounting structure and a crank gear mounting structure for an internal combustion engine that can reduce the diameter and reduce the manufacturing cost.

A ring gear mounting structure according to the present invention includes a rotating shaft, a flange formed on the rotating shaft and having a plurality of grooves formed along the outer peripheral surface, and a ring-shaped gear formed by being mounted on the rotating shaft. A split-type ring gear having a plurality of bolt holes formed along the circumferential direction, and a fixing member disposed on the opposite side of the flange from the ring gear and having bolt holes formed at positions corresponding to the bolt holes of the ring gear. and a fastening bolt that is arranged in the groove and fastens the ring gear and the fixing member with the flange interposed therebetween.
According to the present invention, the flange formed on the rotating shaft is sandwiched between a split ring gear and, for example, a split fixing member, and the fastening bolt is inserted through the insertion hole and mounted in the groove of the flange for positioning. By fastening, the ring gear can be fixed to the rotating shaft. Moreover, since grooves for positioning the fastening bolts are provided in the flange, the outer diameter of the flange can be designed freely, and the mounting structure including the ring gear can be made compact, increasing the degree of freedom in design.

A crank gear mounting structure for an internal combustion engine according to the present invention includes a crank shaft, a gear flange formed on the crank shaft and having a plurality of grooves formed along the outer peripheral surface, and a ring-shaped gear mounted on the crank shaft. and a split-type crank gear formed with a plurality of bolt holes along the circumferential direction, and a bolt disposed on the opposite side of the crank gear with respect to the gear flange and at a position corresponding to the bolt hole of the crank gear It is characterized by comprising a fixing member having a hole formed thereon, and a fastening bolt disposed in the groove and fastening the crank gear and the fixing member with the gear flange interposed therebetween.
According to the present invention, the gear flange formed on the crankshaft is positioned by sandwiching the gear flange formed on the crankshaft between the split type crank gear and the fixed member, the fastening bolt is inserted through the groove of the gear flange, and the crank gear is fastened to the fixed member. can be fixed to the crankshaft. Moreover, since the gear flange is provided with grooves for positioning the fastening bolts, the outer diameter of the gear flange can be freely designed, and the mounting structure including the crank gear can be made compact, increasing the degree of design freedom.
The bolt hole of the crank gear is an insertion hole without a thread groove, the bolt hole of the fixing member is provided with a thread groove, and the fastening bolt is inserted through the bolt hole of the crank gear and passed through the groove portion to the fixing member. It can be a structure that is fastened to. Conversely, the bolt hole of the crank gear is provided with a thread groove, the bolt hole of the fixing member is an insertion hole without a thread groove, and the fastening bolt is inserted through the bolt hole of the fixing member and passes through the groove. A structure in which it is passed through and fastened to the crank gear can also be used. Moreover, both the bolt hole of the crank gear and the bolt hole of the fixed member may be insertion holes without thread grooves and fastened with fastening bolts and nuts.

Also, the crank gear is preferably attached to the gear flange and spigot structure.
By attaching the crank gear to the gear flange with a spigot, the matagi tooth thickness of the crank gear is kept within the allowable range, eliminating the need for adjustment and reducing the number of assembly man-hours.

Moreover, it is preferable that the plurality of grooves arranged in the gear flange have uneven pitch portions in the circumferential direction.
By providing unequal pitch portions in the plurality of grooves arranged in the gear flange, the phase of the crank gear is prevented from being assembled incorrectly and can be mounted in the correct position.

Further, the fastening bolts fastened near the divided portions of the plurality of crank gears may be reamer bolts.
By using reamer bolts to fasten and fix the vicinity of the divided parts of a plurality of crank gears, it is possible to mount them with high accuracy.

Further, a gap may be formed over the entire circumference between the inner peripheral surface of the crank gear and the outer peripheral surface of the crankshaft.
Since the outer peripheral surface of the crankshaft and the inner peripheral surface of the crank gear do not contact each other, the driving force can be transmitted without causing fretting wear, and highly safe power transmission can be performed even when it is necessary to increase the driving torque.

Moreover, it is preferable that the fixed member is a ring-shaped divided backing plate that is formed by combining the backing plates, and that the divided portion between the backing plates is displaced from the divided portion of the crank gear in the circumferential direction.
By displacing the connecting portions of the plurality of crank gears and the divided portions of the plurality of backing plates from each other in the circumferential direction, the mounting strength is increased.

According to the ring gear mounting structure according to the present invention, since the gear flange provided on the rotating shaft is provided with grooves for positioning the bolts for fixing the ring gear, a small-diameter gear flange and ring gear can be used regardless of the output flange provided on the rotating shaft. Formable and compact. In addition, machining of the gear flange does not require jig machining, so that a setup process can be omitted, and automatic machining can be performed from the outer peripheral side using an NC machine, so that the manufacturing cost can be reduced.

According to the crank gear mounting structure for an internal combustion engine according to the present invention, the groove for positioning the fastening bolt for fixing the crank gear is formed in the gear flange provided on the crank shaft so that it can be processed from the outer peripheral side. A small-diameter gear flange and crank gear can be formed regardless of the flange portion, etc., and compactness can be achieved. In addition, the manufacturing cost can be reduced, and automatic processing can be performed from the outer peripheral side using an NC processing machine.

1 is a perspective view of essential parts showing a crank gear mounting structure for an internal combustion engine according to an embodiment of the present invention; FIG. FIG. 2 is an exploded perspective view of the crank gear mounting structure shown in FIG. 1; FIG. 3 is an exploded perspective view of the crank gear mounting structure viewed from the opposite side to FIG. 2; FIG. 2 is a cross-sectional view of the crankshaft shown in FIG. 1 taken along the line AA. It is a front view of a gear flange and an output flange. It is a figure of the process of cutting a U-groove in a gear flange. It is a figure explaining arrangement|positioning of a crank gear, an idle gear, and a cam gear. FIG. 11 is a perspective view showing a conventional first crank gear mounting structure; FIG. 9 is an exploded perspective view of the crank gear mounting structure shown in FIG. 8; FIG. 11 is a perspective view showing a second conventional crank gear mounting structure; FIG. 11 is an exploded perspective view of the crank gear mounting structure shown in FIG. 10; FIG. 11 is a longitudinal sectional view of the crank gear mounting structure shown in FIG. 10; FIG. 11 is a perspective view showing a conventional third crank gear mounting structure; FIG. 14 is an exploded perspective view of the crank gear mounting structure shown in FIG. 13; FIG. 14 is a longitudinal sectional view of the crank gear mounting structure shown in FIG. 13; It is a figure of the process which gives bolt hole processing to a gear flange.

A crank gear mounting structure for an internal combustion engine according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 7. FIG. In this embodiment, a crank gear mounting structure 1 used for a marine engine, for example, will be described.
In the engine crank gear mounting structure 1 shown in FIGS. 1 to 3, a crankshaft 2 is installed for converting reciprocating motion of a connecting rod of a cylinder (not shown) into rotary motion. A ring-shaped output flange 3 is formed integrally with one end of the crankshaft 2, and insertion holes 3a are formed in the output flange 3 at predetermined intervals in the circumferential direction. The insertion hole 3a of the output flange 3 is, for example, a bolt hole for attaching an elastic joint for extracting output from the engine.

A gear flange 5 is integrally formed in the axial direction of the crankshaft 2 in the vicinity of the output flange 3 so as to protrude radially outward and have a ring shape. A plurality of, for example, substantially U-shaped grooves 6 are formed in the outer peripheral surface 5a of the gear flange 5 toward the inner side in the radial direction at predetermined intervals in the circumferential direction. A fastening bolt 11, which will be described later, is inserted into the groove 6 for positioning.

On the crankshaft 2 , on the side opposite to the output flange 3 with respect to the gear flange 5 , a crank gear 7 which is divided into two halves and has an approximately semicircular arc shape is mounted. It is formed into a ring shape by mounting two halves of the crank gear 7 on the crankshaft 2 . The crank gear 7 has gears 7a arranged in the circumferential direction on its outer peripheral surface, and a plurality of insertion holes 7c through which the fastening bolts 11 are inserted are formed at predetermined intervals on both side surfaces sandwiching the gear 7a.

As shown in FIGS. 3 and 4, one side surface of the crank gear 7 is formed with a stepped portion 7b that protrudes from the outer peripheral side. mated. The stepped portion 7b of the crank gear 7 and the gear flange 5 are joined with a spigot joint structure. The insertion hole 7c of the crank gear 7 is formed in a thin region of the stepped portion 7b.

Two half-split backing plates 10 are attached to the crankshaft 2 as fixed members on the side surface of the gear flange 5 on the output flange 3 side. It is assumed that the backing plate 10 is in contact with the gear flange 5 at its sides. Bolt holes 10a are formed at predetermined intervals in the circumferential direction in the side surface of the backing plate 10 on the gear flange 5 side. Two half-split backing plates 10 are mounted on the crankshaft 2 to form a ring shape. Moreover, the connecting position of the half-split backing plate 10 is set such that the ends are connected at a position shifted by a predetermined angle, for example, 90 degrees in the circumferential direction with respect to the connecting position of the ends of the halved crank gear 7. .
At this mounting position, the bolt holes 10a formed in the side surface of the backing plate 10 are formed at positions facing the grooves 6 of the gear flange 5, respectively. The grooves 6 formed in the gear flange 5 are formed at positions facing the insertion holes 7c of the crank gear 7, respectively. Moreover, the backing plate 10 is divided into two in a direction different from that of the gear flange 5. - 特許庁

The insertion hole 7c of the crank gear 7 and the bolt hole 10a of the backing plate 10 are connected to each other by fastening bolts 11 through grooves 6 formed in the gear flange 5. As shown in FIG. In other words, the insertion hole 7c of the crank gear 7 and the bolt hole 10a of the backing plate 10 are positioned in the circumferential direction by the groove 6 of the gear flange 5. As shown in FIG. Four of the plurality of fastening bolts 11 are reamer bolts 12 , which are mounted at positions closest to the connecting portion between both end portions (divided surfaces) of the halved crank gear 7 . By tightening the fastening bolts 11 and the reamer bolts 12 while the gear flange 5 is sandwiched between the crank gear 7 and the backing plate 10, the surface pressure between the gear flange 5 and the crank gear 7 is ensured, and the necessary torque for the crank gear 7 is obtained. can be transmitted.
When mounting the crank gear 7, as shown in FIG. 4, the stepped portion 7b of the two-part crank gear 7 is placed on the shoulder of the gear flange 5 with a spigot and positioned, and the gear flange 5 is positioned on the opposite side of the crank gear 7. is installed on the crankshaft 2 with the backing plate 10 in contact with the side surface of the . Then, the fastening bolt 11 or the reamer bolt 12 is inserted from the insertion hole 7c on the side of the crank gear 7 and screwed into the bolt hole 10a of the backing plate 10 through the groove 6 of the gear flange 5 and fixed.

In the gear flange 5 shown in FIG. 5, the grooves 6 are formed to open radially outward in the circumferential direction, and are arranged in the circumferential direction radially from the center of the crankshaft 2 at regular intervals of an angle θ1, for example. It is Moreover, the intervals of some of the grooves 6 arranged in the circumferential direction of the gear flange 5 are set to an uneven pitch set to the angle θ2 (≠θ1). Similarly to the groove portion 6, the arrangement intervals of the insertion holes 7c of the crank gear 7 and the arrangement intervals of the bolt holes 10a of the backing plate 10 are also formed at an uneven pitch of angle .theta.2.
As a result, erroneous assembly of the crank gear 7 and the backing plate 10, which are divided into two parts, can be prevented by the presence or absence of unequal pitches. The uneven pitches of the groove portion 6, the insertion hole 7c, and the bolt hole 10a are not limited to one location, and may be set at a plurality of locations.
If the position of the crank gear 7 deviates from the position of the crankshaft 2, the timing of rotating the cam for operating the intake and exhaust valves of the cylinder and the fuel injection pump deviates. An eye mark is provided on the engagement portion serving as a reference, and the groove portion 6 of the gear flange 5 is positioned. This makes it possible to match the reciprocating motion of the connecting rod due to the explosion in the cylinder with the fuel injection timing and the opening/closing timing of the intake and exhaust valves.

Moreover, when machining the groove portion 6 in the gear flange 5, as shown in FIG. 6, cutting can be performed by cutting from the outer peripheral surface 5a toward the center in the radial direction using a machining tool such as an end mill 14. Therefore, for example, the grooves 6 can be cut in the outer peripheral surface 5a of the gear flange 5 at predetermined intervals using an NC machine or the like. Since there is no need to drill through the insertion hole 3a of the output flange 3 as in the prior art, the P.D. C. D. and the hole diameter of the insertion hole 3a. The groove portion 6 formed in the gear flange 5 can be made smaller in distance from the center of the crankshaft 2 than the insertion hole 3a of the output flange 3, and the outer peripheral surface 5a of the gear flange 5 can be made small in diameter.
In addition, as shown in FIG. 4, in the assembled state, the inner peripheral surface of the crank gear 7 and the outer peripheral surface (journal) of the crankshaft 2 are provided with a gap k around the entire periphery so that they do not come into contact with each other, thereby preventing fretting during operation. Prevents wear damage. If there is no gap k and the inner peripheral surface of the crank gear 7 and the outer peripheral surface (journal) of the crankshaft 2 come into contact with each other, driving torque will be applied to the crank gear 7 and fretting wear will occur, possibly damaging the crankshaft 2 .

The crank gear mounting structure 1 for an engine according to this embodiment has the above-described structure, and the method for assembling it will now be described.
Prior to the assembly of the crank gear mounting structure 1, as shown in FIG. 6, grooves 6 are formed in the outer peripheral surface 5a of the gear flange 5 of the crankshaft 2 with an end mill 14 using, for example, an NC machine, at predetermined intervals in the circumferential direction. . At this time, the machining interval of the grooves 6 is set to the angle θ1, and the interval of some of the grooves 6 is set to the angle θ2 of unequal pitch.

Next, a half-split crank gear 7 is mounted on the outer peripheral surface of the crankshaft 2 . At this time, the stepped portion 7b on one side surface of the crank gear 7 is placed on one shoulder portion of the gear flange 5 and positioned by the spigot. On the other side of the gear flange 5, a half-split backing plate 10 is attached. At this time, the circumferential end portion of the crank gear 7 and the circumferential end portion of the backing plate 10 are mounted on the crankshaft 2 with a phase shift of a predetermined angle, for example, 90 degrees in the circumferential direction. Moreover, the insertion hole 7c of the crank gear 7 and the bolt hole 10a of the backing plate 10 are aligned with the groove 6 of the gear flange 5 in the axial direction.
Since the insertion hole 7c of the crank gear 7, the groove 6 of the gear flange 5, and the bolt hole 10a of the backing plate 10 are formed at least in one place with an uneven pitch, the two-part crank gear 7 cannot be inserted into the groove 6. By aligning the hole 7c with the bolt hole 10a of the halved backing plate 10, the crank gear 7 and the backing plate 10 can be positioned without error.

Then, the fastening bolts 11 are inserted into the respective insertion holes 7c of the crank gear 7 and sequentially screwed into the bolt holes 10a of the backing plate 10 through the grooves 6 of the gear flange 5 and fixed. Moreover, in the vicinity of each connecting portion of the two crank gears 7, instead of the fastening bolts 11, four reamer bolts 12 are inserted and fixed to position them in the rotational direction. In this way, the crank gear 7 divided into two parts is positioned and fixed to the outer peripheral surface of the crankshaft 2 in a ring shape. In this state, a gap k is formed between the inner peripheral surface of the crank gear 7 and the outer peripheral surface (journal) of the crankshaft 2 so that the entire circumference is out of contact.
When the engine is running, the reciprocating motion of the pistons in the cylinder block is transmitted through the connecting rod and rotates from the crankshaft 2 to the cam gear and the camshaft through the idle gear (not shown) through the crank gear 7. introduce. At this time, since the inner peripheral surface of the crank gear 7 and the outer peripheral surface (journal) of the crankshaft 2 are not in contact with each other due to the gap k, the crankshaft 2 can be prevented from being damaged or broken due to fretting wear.

As described above, in the crank gear mounting structure 1 according to the present embodiment, the gear flange 5 has the groove 6 formed radially inward instead of the through hole. C. D. In addition, the outside diameter of the crank gear 7 is not limited by the hole diameter, and the degree of freedom in designing the outside diameter of the crank gear 7 is increased. Moreover, by reducing the diameter of the gear flange 5, the diameter of the crank gear 7 can also be reduced. This makes it possible to design an engine having a more compact crank gear mounting structure 1 than in the prior art.

Here, the effect of reducing the diameter of the crank gear 7 will be described with reference to FIGS. 7(a) and 7(b). In a four-stroke internal combustion engine, the cam gear rotates once while the crank gear rotates twice, so the ratio of the number of teeth between the crank gear and the cam gear must be 1:2.
The example shown in FIG. 7( a ) is an embodiment using the crank gear mounting structure of the present application, in which a crank gear 121 , an idle gear 122 and a cam gear 123 are arranged in a cylinder block 120 . In this example, the number of teeth of the crank gear 121, the idle gear 122, and the cam gear 123 are, for example, 46, 85, and 92, respectively. The cam gear 123 has a diameter twice that of the crank gear 121, and although the cam gear 123 protrudes from the cylinder block 120 in this example, the gear case (not shown) for covering the cam gear can be made the necessary minimum size. The idle gear 122 is for transmitting rotation from the crank gear 121 to the cam gear 123, and has an appropriate number of teeth according to the arrangement of the gears.
The example shown in FIG. 7(b) is a comparative example using a conventional third crank gear mounting structure. In this comparative example, the numbers of teeth of the crank gear 131, the idle gear 132 and the cam gear 133 are, for example, 64, 57 and 128, respectively. Compared to the above-described embodiment, in the comparative example, the diameter of the crank gear 131 is increased, and the diameter of the cam gear 133 is also increased at the same ratio, so that the cam gear 133 protrudes greatly from the cylinder block 130 . Similarly, the gear case becomes bloated and protrudes greatly to the side of the engine, which unnecessarily presses the space in the engine room.

In addition, since the groove 6 of the gear flange 5 can be processed by an NC processing machine, automatic processing can be performed without the need for attachment and detachment of jigs, and manufacturing costs including labor costs can be reduced.
Moreover, since the outer peripheral surface (journal) of the crankshaft 2 and the inner peripheral surface of the crank gear 7 are held in non-contact by the gap k, fretting wear does not occur during transmission of the driving force. Therefore, even when it is necessary to increase the drive torque of the camshaft, it is possible to provide a highly safe product.
In addition, the transmission torque of the crank gear 7 is also fixed by sandwiching the gear flange 5 between the crank gear 7 and the backing plate 10, so that a high allowable transmission torque equivalent to that of the third crank gear mounting structure described above can be obtained.
Moreover, the matagi tooth thickness of the gear 7a at the connecting portion of the crank gear 7 divided into two is naturally within the allowable range by placing the stepped portion 7b of the crank gear 7 on the outer peripheral surface 5a of the gear flange 5 with a spigot. Since it fits inside, there is no need for adjustment and the number of assembly steps can be reduced.

It should be noted that the crank gear mounting structure 1 for an internal combustion engine according to the present invention is not limited to the above-described embodiment, and appropriate modifications and replacements are possible without departing from the gist of the present invention. Modifications and the like of the present invention will be described below, but the same reference numerals will be used for the same or similar parts and members as those described in the above-described embodiment, and the description will be omitted.

For example, in the above-described embodiment, the fastening bolts 11 and reamer bolts 12 are inserted into the grooves 6 of the gear flange 5 and screwed into the bolt holes 10a of the backing plate 10 to fix the crank gear 7. It is not limited to such a configuration. For example, a nut may be used instead of the backing plate 10, and the fastening bolt 11 or the reamer bolt 12 may be tightened into the nut for fixing. These backing plate 10 and nuts are included in the fixing member.
Further, in the above-described embodiment, the crank gear 7 is attached to the outer peripheral surface 5a of the gear flange 5 at the stepped portion 7b with a spigot, but the spigot structure may not be used. For example, the side surface of the crank gear 7 may be brought into contact with the side surface of the gear flange 5 and the inner peripheral surface thereof may be attached to the outer peripheral surface of the crankshaft 2 .

In the above-described embodiment, the crank gear 7 and the backing plate 10 are divided into two pieces, and two pieces each are provided.
In the above-described embodiment, the internal combustion engine crank gear mounting structure 1 used for a marine engine has been described, but instead, it may be used for a power generation engine or other types of ring gear mounting mechanisms. In this case, instead of the crankshaft 2, a split ring gear (crank gear 7) is attached to the rotating shaft. At that time, a ring gear is attached to the flange instead of the gear flange.

1 Crank Gear Mounting Structure 2 Crankshaft 5 Gear Flange 6 Groove 7 Crank Gear 7a Gear 7b Stepped Portion 7c Insertion Hole 10 Backing Plate 10a Bolt Hole 11 Fastening Bolt 12 Reamer Bolt 14 End Mill

Claims (8)

a crankshaft;
a gear flange formed on the crankshaft and having a plurality of grooves formed along the outer peripheral surface;
A split type crank gear that forms a ring-shaped gear by being attached to the crankshaft and has a plurality of bolt holes formed along the circumferential direction;
a fixing member disposed on the side opposite to the crank gear with respect to the gear flange and having a bolt hole formed at a position corresponding to the bolt hole of the crank gear;
a fastening bolt that is disposed in the groove and fastens the crank gear and the fixing member with the gear flange interposed therebetween;
with
The crankshaft is formed with an output flange having a plurality of through holes arranged in a circumferential direction,
The outer peripheral surface of the gear flange is positioned radially inward of the crankshaft relative to the pitch circle diameter of the insertion hole of the output flange.
A crank gear mounting structure for an internal combustion engine, characterized by: 2. A crank gear mounting structure for an internal combustion engine according to claim 1 , wherein said crank gear is attached to said gear flange and spigot structure. 3. A crank gear mounting structure for an internal combustion engine according to claim 1 , wherein the plurality of grooves arranged in the gear flange have unequal pitch portions in the circumferential direction. 4. The crank gear mounting structure for an internal combustion engine according to any one of claims 1 to 3 , wherein the fastening bolts fastened in the vicinity of the divided portions of the plurality of crank gears are reamer bolts. A crank gear mounting structure for an internal combustion engine according to any one of claims 1 to 4 , wherein a gap is formed over the entire circumference between the inner peripheral surface of the crank gear and the outer peripheral surface of the crankshaft. . The fixing member is a split plate that is formed into a ring shape by combining,
The crank gear mounting structure for an internal combustion engine according to any one of claims 1 to 5 , wherein the divided portion of the backing plate is circumferentially displaced from the divided portion of the crank gear. a crankshaft;
a gear flange formed on the crankshaft and having a plurality of grooves formed along the outer peripheral surface;
A split type crank gear that forms a ring-shaped gear by being attached to the crankshaft and has a plurality of bolt holes formed along the circumferential direction;
a fixing member disposed on the side opposite to the crank gear with respect to the gear flange and having a bolt hole formed at a position corresponding to the bolt hole of the crank gear;
a fastening bolt that is disposed in the groove and fastens the crank gear and the fixing member with the gear flange interposed therebetween;
with
The plurality of grooves arranged in the gear flange have uneven pitch portions in the circumferential direction.
A crank gear mounting structure for an internal combustion engine, characterized by: a crankshaft;
a gear flange formed on the crankshaft and having a plurality of grooves formed along the outer peripheral surface;
A split type crank gear that forms a ring-shaped gear by being attached to the crankshaft and has a plurality of bolt holes formed along the circumferential direction;
a fixing member disposed on the side opposite to the crank gear with respect to the gear flange and having a bolt hole formed at a position corresponding to the bolt hole of the crank gear;
a fastening bolt that is disposed in the groove and fastens the crank gear and the fixing member with the gear flange interposed therebetween;
with
The fastening bolts fastened in the vicinity of the divided portions of the plurality of crank gears are reamer bolts.
A crank gear mounting structure for an internal combustion engine, characterized by:

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