JP2018168966A - Supporting structure of crankshaft - Google Patents

Abstract

To provide a supporting structure of a crankshaft that can easily support an end part of the crankshaft.SOLUTION: A flywheel 8 is attached to an end part 11a of a crankshaft 10 rotatably supported by a crankcase 2 of an engine 1 and protruding from the crankcase 2 so as to rotate integrally. A female screw member 17 is screwed to the end part 11a of the crankshaft 10, and the flywheel 8 is positioned in an axial direction with respect to the crankshaft 10. A boss part 18a of a stator 18 and a rolling bearing 19 are fixed to an inner cylinder part 3b of a cover 3 covering the end part 11a of the crankshaft 10 by a plurality of bolts 21 via a hold plate 20. The cover 3 is attached beside the crankcase 2, and an inner ring 19a of the rolling bearing 19 is fitted to an outer periphery of a bearing seat part 17a of the female screw member 17.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a support structure for a crankshaft that is rotatably supported by an engine crankcase.

  As a crankshaft of a conventional engine, for example, there is a split crankshaft having a plurality of divided crank journals, a crankpin that supports a connecting rod, and a crank web that connects the crank journal and the crankpin.

  Such a split crankshaft is rotatably supported by a crankcase of an engine via a bearing, and an end portion of the crankshaft protrudes from the side of the crankcase.

  A flywheel is attached to the end of the crankshaft so as to rotate integrally with the crankshaft, and the flywheel is covered with a cover attached to the side of the crankcase.

  Usually, when the connecting rod and the piston attached to the end of the connecting rod move forward and backward, the rotation of the crankshaft repeats acceleration and deceleration. In accordance with the rotation of the crankshaft that repeatedly accelerates and decelerates, a large inertial force acts on a fly hole with a large mass, and a twisting force about the axis acts on the end of the crankshaft on the flywheel side.

  In order to suppress such a twisting force, a crankshaft support structure is disclosed in which the crankshaft protrudes outward from the flywheel and its end is rotatably supported by a bearing provided on the crankcase cover. (For example, refer to Patent Document 1).

  In the crankshaft support structure described in Patent Document 1, the crankshaft is supported on both sides of the flywheel by bearings provided on the crankcase bearing and the cover. For this reason, it becomes easy for the flyhole to follow and rotate according to the rotation of the crankshaft.

  By making the flywheel easier to rotate, when acceleration / deceleration occurs in the rotation of the crankshaft, the torsional force acting on the crankshaft acting on the crankshaft due to the inertial force of the flywheel can be suppressed.

JP 2007-2873 A

  By the way, the crankshaft described in Patent Document 1 uses an extended end of the crankshaft so that the end of the crankshaft is supported by a bearing provided on the cover. In this case, it is necessary to manufacture a new crankshaft, and it is necessary to disassemble the engine in order to attach a new crankshaft to the crankcase.

  Therefore, an object of the present invention is to provide a crankshaft support structure that can easily support the end of the crankshaft.

  In order to solve the above problems, a crankshaft support structure according to the present invention is rotatably supported by a crankcase of an engine, and an end portion of the crankshaft that protrudes from the crankcase, and an end portion of the crankshaft A flywheel that is fitted to the outer periphery of the crankshaft, a female screw member that is screwed to the end of the crankshaft, and a cover that is attached to the side of the crankcase and covers the end of the crankshaft And a rolling bearing attached to the cover, wherein the outer peripheral portion of the end portion of the crankshaft and the inner peripheral portion of the flywheel are tapered inward in the radial direction toward the axially outer side of the crankshaft. The crankshaft is formed by the female screw member that is threadedly coupled to an end of the crankshaft. The flywheel is positioned in the axial direction with respect to the crankshaft in a state where the taper portion of the flywheel is coaxially butted against the taper portion of the shaft, and the female thread member is A cylindrical bearing seat extending in the axial direction is provided, and the female thread member is screwed to the end of the crankshaft so that the inner ring of the rolling bearing is fitted to the bearing seat. The configuration can be adopted.

  According to this configuration, the crankshaft can be extended in length by the cylindrical female screw member screwed to the end. Therefore, unlike the conventional case, it is not necessary to newly manufacture a crankshaft having an extended end, and the inner ring of the rolling bearing provided on the cover can be fitted into the bearing seat of the female screw member. .

  In this configuration, the cover includes a cylindrical outer cylinder portion that covers an end portion of the crankshaft, a cylindrical inner cylinder portion that is coaxially positioned on the radially inner side of the outer cylinder portion, and the outer cylinder. And an annular plate portion for connecting the outer end portion in the axial direction of the inner cylinder portion, and the rolling bearing is coaxially formed by an annular hold plate with respect to the inner end portion in the axial direction of the inner cylinder portion. The structure fixed to can be employ | adopted.

  According to this configuration, the rolling bearing fixed to the inner cylindrical portion of the cover can be easily replaced by attaching and detaching the hold plate.

  Further, in order to solve the above-described problem, a method for constructing a crankshaft support structure according to the present invention includes a crankcase rotatably supported by a crankcase of an engine, and an end portion of the crankshaft from the crankcase. The flywheel is protruded and attached to the end of the crankshaft so as to rotate integrally. The above-mentioned female screw member is screwed to the end of the crankshaft so that the flywheel is pivoted with respect to the crankshaft. A rolling bearing is attached to the cover that covers the end of the crankshaft, and the cover is attached to the side of the crankcase, and the rolling bearing is fitted to the outer periphery of the bearing seat of the female screw member. A construction method can be adopted.

  According to the present invention, the end of the crankshaft is easily supported by screwing a female screw member to the end of the crankshaft and fitting a rolling bearing provided on the cover to the bearing seat of the female screw member. be able to.

  Further, when the female screw member is screwed to the end of the crankshaft, the flywheel is connected to the crankshaft in a state where the tapered portion of the flywheel is coaxially butted against the tapered portion of the crankshaft. With respect to the axial direction. For this reason, the female screw member contributes to the positioning of the flywheel and the support of the end portion of the crankshaft.

Longitudinal sectional view of the crankshaft support structure of the first embodiment according to the present invention The exploded perspective view of the principal part of the support structure of a crankshaft same as the above Exploded sectional view of the main part of the crankshaft support structure Longitudinal sectional view showing the main part of the crankshaft support structure The longitudinal cross-sectional view which shows the principal part of the support structure of the crankshaft of 2nd embodiment

  A crankshaft support structure according to a first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view showing a support structure of a crankshaft 10 used in an engine 1 for a single cylinder motorcycle. FIG. 2 is an exploded perspective view for explaining the support structure of the crankshaft 10. FIG. 3 is an exploded cross-sectional view of a main part of the crankshaft support structure. FIG. 4 is a longitudinal sectional view showing a main part of the support structure of the crankshaft 10.

  In the engine 1, a crankshaft 10 is rotatably supported by a crankcase 2 which is a lower part of a cylinder block, and a cover 3 covering an end portion 11a of the crankshaft 10 protruding from the side of the crankcase 2 is provided on the crankcase 2 side. It is attached to the direction.

  The crankcase 2 has a pair of openings 2a and 2b on both sides below it. The openings 2a and 2b are circular and located on a concentric shaft, and the opening 2a located on one axial side of the crankshaft 10 has a bearing 4 fitted and fixed to the inner periphery thereof. A bearing 5 is fitted and fixed to the inner periphery of the opening 2b located on the other axial side of the shaft 10.

  As shown in FIG. 1, the bearings 4 and 5 are ball bearings and support the crankshaft 10 to be rotatable. The bearings 4 and 5 are not limited to ball bearings as long as the crankshaft 10 can be rotatably supported, and roller bearings and sliding bearings may be used.

  The crankshaft 10 includes a pair of crankshaft portions 11 and 12 arranged in a state of being opposed to each other on a concentric shaft, and a crank web portion 13 formed integrally with the opposite end portions of the crankshaft portions 11 and 12. , 14 are connected to each other with a crank pin 15 that connects the two.

  The crankshaft portion 11 has a columnar shape and is rotatably supported by the bearing 4, and the crankshaft portion 12 has a columnar shape and is rotatably supported by the bearing 5. An end 11a of the crankshaft 11 (an end 11a of the crankshaft 10) protrudes from the opening 2a of the crankcase 2 in one axial direction. The end of the crankshaft portion 12 protrudes from the opening 2b of the crankcase 2 to the other axial direction.

  Moreover, as shown in FIG. 3, the crankshaft part 11 has the taper part 11b and the external thread part 11c which were formed in the outer peripheral part of the edge part 11a. The taper portion 11b is formed so as to incline radially inward toward the outer side in the axial direction, extends in the axial direction, and has a fitting groove 11d into which a key member 16 described later is fitted. The male screw portion 11c is formed on one side in the axial direction with respect to the taper portion 11b.

  The crank web portions 13 and 14 are disposed at the lower end of a cylinder chamber S formed by the cylinder block of the engine 1 and the crankcase 2. The crank web portions 13 and 14 are connected by a crank pin 15 with a connecting rod 6 formed at the lower end of a piston (not shown) sandwiched from both sides in the axial direction. The connecting rod 6 sandwiched between the crank web portions 13 and 14 can swing around the crank pin 15 as a central axis.

  A sprocket 7 and a flywheel 8 are fixed to the end 11 a of the crankshaft 10. The sprocket 7 is located closer to the crankcase 2 than the flywheel 8 and is connected to a camshaft (not shown) via a chain.

  The flywheel 8 includes a cylindrical boss portion 8a fitted to the end portion 11a of the crankshaft 10, an annular plate portion 8b extending radially outward from the other axial end of the boss portion 8a, and an annular plate portion 8b. And a cylindrical portion 8c extending in one axial direction from the outer peripheral edge of the outer periphery.

  As shown in FIG. 3, the boss 8a of the flywheel 8 includes a tapered portion 8d having an inner circumferential portion inclined radially inward toward one axial end side (axially outer side), and an axial direction of the inner circumferential portion. And a keyway 8e formed on the surface.

  The flywheel 8 is fitted to the outer peripheral portion of the crankshaft portion 11 with the tapered portion 8d of the boss portion 8a being coaxially butted against the tapered portion 11b of the crankshaft portion 11. In this fitting, the key member 16 is fitted in the fitting groove 11d of the tapered portion 11b of the crankshaft portion 11. When the key member 16 is engaged in a key groove 8 e formed in the boss portion 8 a of the flywheel 8, the flywheel 8 rotates integrally with the crankshaft 10.

  The flywheel 8 is fixed so that a one-way clutch 9 disposed between the flywheel 8 and the sprocket 7 rotates integrally. The one-way clutch 9 has an annular shape, and the end portion 11a of the crankshaft 10 is inserted through the boss portion 22a of the driven gear 22 inserted through the inner periphery thereof.

  A needle roller bearing 23 is fitted into the inner peripheral portion of the boss portion 22 a of the driven gear 22. The driven gear 22 is rotatably attached to the end portion 11 a of the crankshaft 10 by a needle roller bearing 23.

  The one-way clutch 9 transmits driving force from a starter motor (not shown) to the flywheel 8 via the driven gear 22 when the engine is started, and is used to rotate the crankshaft 10.

  The one-way clutch 9 rotates together with the flywheel 8 to increase the weight of the flywheel 8 and secures the inertia weight of the flywheel 8.

  The female screw member 17 has a cylindrical shape with one axial end closed, and a bearing seat portion 17a having a female screw portion on the inner periphery, and a flange portion 17b radially outward from the other axial end of the bearing seat portion 17a. have. Further, the female screw member 17 has an outer periphery at one end in the axial direction having a regular hexagonal cross section, and can be screw-coupled with an existing tool.

  The outer peripheral surface of the bearing seat portion 17a is a cylindrical surface, and the inner periphery of the inner ring 19a of the rolling bearing 19 attached to the cover 3 described later is fitted (see FIG. 4). The flange portion 17 b presses the tapered portion 8 d of the boss portion 8 a of the flywheel 8 against the tapered portion 11 b of the crankshaft portion 11 to position the flywheel 8 in the axial direction with respect to the end portion 11 a of the crankshaft 10.

  The cover 3 closes the space in the crankcase 2 and covers the outer end of the end 11a of the crankshaft 10 and the outer periphery of the cylindrical portion 8c of the flywheel 8, and the radially inner side of the outer cylindrical portion 3a. The cylindrical inner cylinder part 3b and the annular plate part 3c which connects the axial direction one end part of the outer cylinder part 3a and the inner cylinder part 3b.

  The cover 3 includes a cap member 3d in which an outer cylinder portion 3a and an inner cylinder portion 3b are arranged coaxially with each other, and closes one axial end portion of the inner cylinder portion 3b.

  As shown in FIG. 2, the cover 3 has a stator 18 and a rolling bearing 19 positioned on the inner periphery of the boss portion 18 a of the stator 18, with respect to the other axial end of the inner cylinder portion 3 b. Are fixed with a plurality of bolts 21 via

  In the cover 3 of this embodiment, the one end in the axial direction means the outer end in the axial direction of the crankshaft 10, and the other end in the axial direction means the inner end in the axial direction of the crankshaft 10. .

  In the stator 18, a plurality of coil bundles are fixed radially on the outer periphery of a cylindrical boss portion 18a. A plurality of bolts 21 are inserted into the boss portion 18 a of the stator 18 and the fixing hole portion 20 a of the hold plate 20, and the boss portion 18 a is pressed against the inner cylinder portion 3 b of the cover 3 by the hold plate 20 by screw connection of the bolt 21. It is in a state.

  In the stator 18, the rotation of the crankshaft 10 causes the cylindrical portion 8 c of the flywheel 8 as a rotor to rotate on the radially outer side of the stator 18, thereby generating electric power by electromagnetic induction.

  The rolling bearing 19 is a ball bearing, and the inner periphery of the inner ring 19 a is fitted into the bearing seat portion 17 a of the female screw member 17. In this state, the end portion 11 a of the crankshaft 10 is rotatably supported by the rolling bearing 19 via the female screw member 17.

  The inner ring 19a of the rolling bearing 19 and the bearing seat portion 17a of the female screw member 17 can be fitted with an intermediate fit. Accordingly, it is preferable that the inner ring 19a can be easily fitted to and removed from the bearing seat portion 17a.

  As shown in FIG. 2, the hold plate 20 is an annular plate member, and is provided with fixed hole portions 20 a at three locations in the circumferential direction. Each fixing hole 20a is equally arranged in the circumferential direction and protrudes outward in the radial direction.

  The crankshaft support structure of the present invention is configured as described above. Next, a construction method of the crankshaft support structure will be described below.

  First, the crankshaft 10 is rotatably supported by bearings 4 and 5 on the crankcase 2 of the engine, and the end 11a of the crankshaft 10 is protruded from the opening 2a on the side of the crankcase 2.

  Subsequently, the sprocket 7 is fixed to the end 11 a of the crankshaft 10 so as to rotate integrally with the opening 2 a side of the crankcase 2. Further, the boss portion 22 a of the driven gear 22 is inserted into the end portion 11 a of the crankshaft 10 via the needle roller bearing 23 so as to be rotatable.

  Next, the one-way clutch 9 is inserted into the boss portion 22 a of the driven gear 22, and the end portion 11 a of the crankshaft 10 is inserted into the boss portion 8 a of the flywheel 8 fixed to the one-way clutch 9.

  At the time of this insertion, the key member 16 is fitted into the fitting groove 11d of the crankshaft portion 11 so that the circumferential positions of the key member 16 and the key groove 8e of the boss portion 8a of the flywheel are matched.

  Thereafter, the female screw member 17 is screwed to the male thread portion 11c of the end portion 11a of the crankshaft 10 via a washer. As a result, the flywheel 8 is in a state in which the tapered portion 8d of the boss portion 8a is coaxially pressed against the tapered portion 11b of the crankshaft portion 11, and is positioned in the axial direction with respect to the end portion 11a of the crankshaft 10. The

  Then, the rolling bearing 19 is fitted inside the boss portion 18a of the stator 18 in the radial direction. The boss portion 18 a of the stator 18 and the rolling bearing 19 are arranged at the axially inner end portion of the inner cylinder portion 3 b of the cover 3.

  Subsequently, as shown in FIG. 3, the boss portion 18 a of the stator 18 and the rolling bearing 19 are fixed to the inner end portion in the axial direction of the inner cylindrical portion 3 b of the cover 3 with a plurality of bolts 21 via the hold plate 20.

  Finally, the cover 3 is attached to the side of the crankcase 2, and the inner ring 19 a of the rolling bearing 19 is fitted to the outer periphery of the bearing seat portion 17 a of the female screw member 17. A support structure for the crankshaft 10 is constructed as described above.

  According to the support structure of the crankshaft 10 of this embodiment, the female screw member 17 is screwed to the end portion 11a of the crankshaft 10, and the rolling bearing 19 provided on the cover 3 is attached to the bearing seat portion 17a of the female screw member 17. By fitting, the end portion 11a of the crankshaft 10 can be easily rotatably supported.

  This support makes it easy for the flywheel 8 to follow and rotate according to the rotation of the crankshaft 10, and acts on the crankshaft 10 by the inertial force of the flywheel 8 when acceleration / deceleration occurs in the rotation of the crankshaft 10. The twisting force around the shaft can be suppressed. Further, the bending at the end 11a of the crankshaft 10 can be suppressed.

  Further, since the screw member 17 is screwed to the end portion 11 a of the crankshaft 10, the tapered portion 8 d of the flywheel 8 is abutted coaxially with the tapered portion 11 b of the crankshaft portion 11. For this reason, the female screw member 17 contributes to the axial positioning of the flywheel 8 with respect to the crankshaft 10 and the support of the end portion 11a of the crankshaft 10.

  In this embodiment, a support structure for the crankshaft 10 is adopted in a single-cylinder engine of a motorcycle in which the side of the crankcase 2 is closed by a cover 3 that is detachably attached. However, the embodiment is not limited to the number of cylinders and the cylinder arrangement of the engine, and is adopted for all engines having a structure in which the end 11a of the crankshaft 10 faces the inner surface of the cover 3. can do.

  In the cover 3, the boss portion 18 a of the stator 18 and the rolling bearing 19 are fixed to the inner cylinder portion 3 b with the plurality of bolts 21 via the hold plate 20, but the present invention is not limited thereto. Only the rolling bearing 19 may be fixed to the inner cylindrical portion 3b of the cover 3, and the flywheel 8 may not have the cylindrical portion 8c as a rotor. That is, a mode in which power generation is not performed in the cover 3 may be employed.

  Furthermore, the rolling bearing 19 is not limited to the ball bearing illustrated in this embodiment. Any member that can rotatably support the end portion 11a of the crankshaft 10 may be used. For example, a roller bearing or a sliding bearing may be employed.

  Next, a crankshaft support structure according to a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a rolling bearing 19 is attached to the cap member 3d of the cover 3, and the end 11a of the crankshaft 10 is rotatably supported by the rolling bearing 19 via the female screw member 17. This is different from the first embodiment. Members considered to be the same as those in the first embodiment have the same reference numerals, and the description thereof is omitted.

  In this embodiment, as shown in FIG. 5, the stator 18 is fixed to the other axial end portion of the inner cylinder portion 3 b of the cover 3 by a plurality of bolts 21. For this reason, the hold plate 20 in the first embodiment is not necessary.

  The cap member 3d of the cover 3 can be screwed to the inside of the inner cylindrical portion 3b of the cover 3, and a rolling bearing 19 is fitted on the inner peripheral portion thereof. Further, the cap member 3d has a hexagonal hole 3e formed at the center of one axial end portion.

  The rolling bearing 19 fitted to the cap member 3 d is in a state in which the inner ring 19 a is fitted to the tip end portion of the bearing seat portion 17 a of the female screw member 17. In this state, the end portion 11 a of the crankshaft 10 is rotatably supported by the rolling bearing 19 via the female screw member 17.

  In this embodiment, the end 11a of the crankshaft 10 can be easily rotated by fitting the rolling bearing 19 provided on the inner peripheral portion of the cap member 3d with the cover 3 being attached to the side of the crankcase 2. Can be supported.

  A rolling bearing 19 is attached to the inner peripheral portion of the cap member 3d of the cover 3. For this reason, maintenance can be easily performed with respect to the support state of the crankshaft 10 by attaching and detaching the cap member 3d with the tool put in the hexagonal hole 3e.

DESCRIPTION OF SYMBOLS 1 Engine 2 Crankcase 2a, 2b Opening part 3 Cover 3a Outer cylinder part 3b Inner cylinder part 3c Ring plate part 3d Cap member 3e Hexagonal hole 4, 5 Bearing 6 Connecting rod 7 Sprocket 8 Flywheel 8a Boss part 8b Ring plate part 8c Cylindrical part 8d Taper part 8e Key groove 9 One-way clutch 10 Crankshaft 11, 12 Crankshaft part 11a End part 11b Taper part 11c Male thread part 11d Fitting groove 13, 14 Crank web part 15 Crank pin 16 Key member 17 Female thread Member 17a Bearing seat portion 17b Collar portion 18 Stator 18a Boss portion 19 Rolling bearing 19a Inner ring 20 Hold plate 20a Fixing hole portion 21 Bolt 22 Driven gear 22a Boss portion 23 Needle roller bearing S Cylinder chamber

Claims (3)

A crankshaft that is rotatably supported by the crankcase of the engine and whose end projects from the crankcase, a flywheel that fits to rotate integrally with the outer periphery of the end of the crankshaft, and an end of the crankshaft A female screw member screwed to the part, a cover attached to a side of the crankcase, covering an end of the crankshaft, and a rolling bearing attached to the cover,
The outer peripheral portion of the end portion of the crankshaft and the inner peripheral portion of the flywheel have a tapered portion that inclines radially inward toward the axially outer side of the crankshaft, and a screw is attached to the end portion of the crankshaft. The flywheel is positioned in the axial direction with respect to the crankshaft in a state where the tapered portion of the flywheel is coaxially butted against the tapered portion of the crankcase by the female screw member to be coupled. Yes,
The female screw member has a cylindrical bearing seat portion extending in the axial direction of the crankshaft, and the female screw member is threadedly coupled to an end portion of the crankshaft, and the rolling bearing is attached to the bearing seat portion. The crankshaft support structure is designed so that the inner ring can be fitted. The cover includes a cylindrical outer cylinder portion that covers an end of the crankshaft, a cylindrical inner cylinder portion that is coaxially positioned radially inward of the outer cylinder portion, and the outer cylinder portion and the inner cylinder. An annular plate portion connecting the axially outer end portions of the portions,
2. The crankshaft support structure according to claim 1, wherein the rolling bearing is coaxially fixed to an axially inner end portion of the inner cylinder portion by an annular hold plate.   The crankshaft is rotatably supported by the crankcase of the engine, the end of the crankshaft is protruded from the crankcase, and the flywheel is attached to the end of the crankshaft so as to rotate integrally. The female screw member according to claim 1 is screwed to the portion, the flywheel is axially positioned with respect to the crankshaft, and a rolling bearing is attached to a cover that covers an end of the crankshaft, A construction method of a crankshaft support structure in which a cover is attached to a side of the crankcase, and the rolling bearing is fitted to an outer periphery of a bearing seat portion of the female screw member.

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