JP2008151176A - Support structure for crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide support structure for a crankshaft capable of surely sealing lubricating oil in a crank chamber with simple structure. <P>SOLUTION: In the support structure for the crankshaft provided with a right ball bearing 33 rotatably supporting the crankshaft 11 and a bearing energizing means 68 elastically pressing an outer ring 33a of the right ball bearing 33 in a direction separating from an inner surface of a right bearing support hole 66, the bearing energizing member 68 is composed of a spring energizing member 69 and a spring seat member 70 fixed on a crank case 5, a housing hole 67 communicating to a right bearing support hole 66 and provided with the spring energizing member 69 on one end and having the spring seat member 70 fixed on an opening part 67a in another end side and housing the bearing energizing means 68 is provided on a right side wall part 65 of the crank case 5 having the right bearing support hole 66 formed therein, and the opening part 67a is blocked by the spring seat member 70 and is sealed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a support structure for a crankshaft.

  A crankshaft that converts linear motion of a piston sliding in a cylinder into rotational motion is supported by a crankcase via a ball bearing. At this time, if there is a gap between the crankcase and the outer ring of the ball bearing, a so-called crank hitting sound may occur during the sliding movement of the piston. Therefore, there is disclosed a crankshaft support structure in which the generation of cranking noise is stably suppressed by the bearing urging means that elastically presses the outer ring of the ball bearing (see, for example, Patent Document 1). .

JP 2004-116705 A

  However, when such a crankshaft support structure is applied to a case where a dry space having a cooling air passage or the like is formed on the side of the crankcase, lubrication is provided between the outer ring of the ball bearing and the crankcase. A mechanism for sealing oil is required, and there is a problem that the structure becomes complicated and a problem that costs increase.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a crankshaft support structure capable of reliably sealing lubricating oil in the crank chamber with a simple structure.

  In order to solve the above-mentioned problems, a crankshaft support structure according to the present invention is fitted into a bearing support hole (for example, the right bearing support hole 66 in the embodiment) provided in the crankcase, so that the crankshaft can freely rotate. Bearing (for example, the right ball bearing 33 in the embodiment), and bearing urging means that elastically presses the outer ring of the bearing away from the inner surface of the bearing support hole. The biasing means includes a spring receiving member fixed to the crankcase and a spring biasing member that is biased and supported by the spring receiving member and engages with the outer ring of the bearing. A spring urging member is disposed at one end of the wall of the crankcase in which the bearing support hole is formed (for example, the right side wall 65 in the embodiment) and communicates with the bearing support hole. A receiving hole for receiving the bearing urging means is provided by fixing the spring receiving member to the portion, and the opening is closed and sealed by the spring receiving member.

  In such a crankshaft support structure according to the present invention, the generator is disposed in the space where the opening is formed across the wall, and the generator stator is fixed in the vicinity of the accommodation hole. It is preferable to provide a mounting hole.

  In addition, an auxiliary machine drive unit (for example, oil pump drive gear 51 in the embodiment) for driving an auxiliary machine (for example, oil pump 53 in the embodiment) is provided on the crankshaft adjacent to the bearing to supplement the accommodation hole. It is preferably provided around the machine drive unit.

  Furthermore, the bearing urging means is preferably provided on the piston side with respect to the axis of the crankshaft.

  When the crankshaft support structure according to the present invention is configured as described above, it is not necessary to provide a bolt hole for pressing the bearing urging means in addition to the bearing hole of the bearing urging means. Therefore, the processing man-hours can be reduced and a compact configuration can be achieved. Further, the number of parts can be reduced because the spring plate support is not required. Furthermore, even if a dry space is provided in the outer space of the bearing, the lubricating oil in the crank chamber can be reliably sealed with a simple structure without complicating the structure.

  At this time, if a generator support hole that supports the stator of the generator is provided around the accommodation hole, the accommodation hole and the support hole can be processed in the same member and in the same direction, so that the number of processing steps can be reduced. Cost is reduced.

  In addition, if an accessory drive unit is provided on the side of the bearing, and an accommodation hole is provided adjacent to the accessory drive unit, the accessory drive unit can be arranged in a compact manner using a dead space around the accommodation hole. Can do.

  Furthermore, if the bearing urging means is arranged on the piston side with respect to the axis of the crankshaft, the bearing can be urged in the direction of receiving the explosion pressure with respect to the crankshaft. Can be suppressed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, the configuration of the power unit 1 to which the crankshaft support structure according to the present invention is applied will be described with reference to FIGS. 1 and 2. This power unit 1 is used for a motorcycle. In the following description, the direction of the arrow F shown in FIG. 2 is the forward direction, and the direction of the arrow U is the upward direction.

  The power unit 1 includes a cylinder head cover 2, a cylinder head 3, a cylinder block 4, a crankcase 5, a crankcase cover 6, and a gear case 7. A cylinder sleeve 8 extending in a cylindrical shape in the front-rear direction is press-fitted into the cylinder block 4, and a cylinder chamber 8 a is formed surrounded by the cylinder sleeve 8. A piston 9 is disposed in the cylinder chamber 8a so as to be slidable in the front-rear direction. The piston 9 extends in the left-right direction into a crank chamber 5a formed in the crankcase 5 via a connecting rod 10 and rotates. It is connected to a crankshaft 11 that is freely held. The crankshaft 11 is composed of a left crankshaft half body 11L and a right crankshaft half body 11R, and the connecting rod 10 is formed by a crankpin 12 disposed so as to connect the left and right crankshaft half bodies 11L and 11R. It is connected to the crankshaft 11.

  The combustion chamber 13 formed by the cylinder sleeve 8, the cylinder head 3, and the piston 9 has an intake port 16 and an exhaust port 17 via an intake port 14 and an exhaust port 15 formed in the cylinder head 3, respectively. Communicate. The saddle-shaped intake valve 18 and exhaust valve 19 have one end attached to the valve shaft and supported by the retainer, and the other end supported by the cylinder head 3 by valve springs 20 and 21, respectively. The mouth 15 is always biased in the direction of closing.

  Further, a camshaft 22 for opening and closing the intake valve 18 and the exhaust valve 19 is supported in the cylinder head 3 so as to extend in the left-right direction so as to be rotatable. A cam driven sprocket disposed on the camshaft 22. 23 and a timing chain 25 is wound around the camshaft sprocket 24 disposed on the crankshaft 11 (left crankshaft half 11L). Therefore, the camshaft 22 rotates in accordance with the rotation of the crankshaft 11, and the cams 26 and 27 formed on the camshaft 22 push one end side of the rocker arms 28 and 29 forward, so that these rocker arms The other end side of 28 and 29 swings backward to push out the intake valve 18 and the exhaust valve 19 to open and close the intake port 14 and the exhaust port 15.

  A throttle body 30 having a throttle valve is connected to the intake port 16 so as to be in a clean state by an air cleaner (not shown), the amount of air flowing in is adjusted, mixed with fuel, and taken from the intake port 16. It is supplied to the combustion chamber 13 through the port 14. Then, after the air-fuel mixture is compressed by the piston 9, it is ignited and burned by the spark plug 31 attached to the cylinder head 3, and becomes energy for rotating the crankshaft 11 through the piston 9, and then as exhaust gas The gas is discharged from the exhaust port 15 through the exhaust port 17 to the outside.

  The journal portions of the left and right crankshaft halves 11L and 11R constituting the crankshaft 11 are rotatably supported by the crankcase 5 via the left and right ball bearings 32 and 33, respectively. The left side portion of the crankcase 5 is formed so as to extend rearward. A crankcase cover 6 is attached to the left side surface of the crankcase 5, and a transmission chamber 34 is formed surrounded by the crankcase 5 and the crankcase cover 6. A transmission 35 is stored. A countershaft 36 is attached which is positioned behind the crankshaft 11 and extends substantially parallel to the crankshaft 11 and is rotatably held by the crankcase 5 and the crankcase cover 6.

  The transmission 35 is attached to the journal part of the left crankshaft half 11 </ b> L extending into the transmission chamber 34, and is attached to a substantially central part of the drive pulley 37 and the countershaft 36 that rotate integrally with the countershaft 36. A driven pulley 38 that can be rotated relative to the countershaft 36, a clutch 39 that engages and disengages the driven pulley 38 and the countershaft 36, and a drive pulley 37 that is wound around the drive pulley 37 and the driven pulley 38. It comprises a V-belt 40 that transmits the rotation of 37 to the driven pulley 38.

  The drive pulley 37 is a fixed pulley half 37a attached to the journal portion of the left crankshaft half 11L so as to be integrally rotatable. The drive pulley 37 is relatively movable in the axial direction relative to the fixed pulley half 37a. The shaft half body 11L and a movable pulley half body 37b that can rotate integrally with each other are configured, and the V-belt 40 is sandwiched between the fixed and movable pulley halves 37a and 37b. On the other hand, the driven pulley 38 is a fixed pulley half 38a attached to the counter shaft 36 so as to be rotatable relative to the counter shaft 36. The driven pulley 38 is relatively movable in the axial direction with respect to the fixed pulley half 38a and is rotated relative to the counter shaft 36. The V-belt 40 is sandwiched between these fixed and movable pulley halves 38a and 38b.

  A ramp plate 41 is fixedly attached to the left crankshaft half 11L outside the movable pulley half 37b constituting the drive pulley 37 (on the left ball bearing 32 side) so as to cover the outside of the movable pulley half 37b. A weight roller space 42 is formed surrounded by the movable pulley half 37b and the lamp plate 41, and the weight roller 43 is stored therein. The weight roller space 42 is formed such that the distance in the left-right direction becomes narrower as it moves away from the crankshaft 11. The movable pulley half 38 b constituting the driven pulley 38 is arranged side by side with the clutch 39, and the movable pulley half 38 b is fixed between the movable pulley half 38 b and the clutch 39. A spring 44 is disposed so as to be biased by 38a.

  In the transmission 35 configured as described above, when the crankshaft 11 is driven to rotate, the drive pulley 37 rotates, and this rotation is transmitted to the driven pulley 38 via the V-belt 40, and further, the countershaft is connected via the clutch 39. 36 is rotationally driven. At this time, the magnitude of the centrifugal force acting on the weight roller 43 changes according to the rotational speed of the crankshaft 11, and the weight roller 43 causes the movable pulley half 37b of the drive pulley 37 to move according to the magnitude of this centrifugal force. Extruding to the left, the winding radius of the V belt 40 around the drive pulley 37 changes. The movable pulley half 38b of the driven pulley 38 slides in the left-right direction so that the tension of the V belt 40 and the biasing force of the spring 44 are balanced. Therefore, the tension of the V-belt 40 changes due to the change of the winding radius of the drive pulley 37, and thereby the winding radius of the V-belt 40 with respect to the driven pulley 38 changes. Therefore, the transmission 35 continuously changes the winding radius of the pulleys 37 and 38 of the V-belt 40 in accordance with the rotational speed of the crankshaft 11, thereby continuously changing the gear ratio (continuously. ) Can be changed.

  A gear case 7 is attached to the rear portion of the crankcase 5 so as to cover the right side surface of the rear portion, and a gear chamber 45 is formed surrounded by the rear portion of the crankcase 5 and the gear case 7. The right end portion of the countershaft 35 supported by the crankcase 5 protrudes into the gear chamber 45. Further, behind the countershaft 36, an idle shaft 46 that is disposed substantially in parallel with the countershaft 36 and is rotatably supported by the crankcase 5 and the gear case 6, and further behind the countershaft 36, A rear wheel shaft (final shaft) 47 is provided that is disposed substantially in parallel and is rotatably held by the crankcase 5 and the gear case 6. A reduction gear train 48 is disposed on the counter shaft 36, the idle shaft 46, and the rear wheel shaft 47, and the rotation of the counter shaft 36 is transmitted to the rear wheel shaft 47 by the reduction gear train 48. A rear wheel (not shown) attached to the rear wheel shaft 47 is rotationally driven.

  A drum brake 49 for braking the rotation of the rear wheel shaft 47 is provided between the gear case 6 and the rear wheel shaft 47. A kick start mechanism 50 is provided on the left side and the rear side of the left crankshaft half 11L.

  On the other hand, the base end portion of the journal portion of the right crankshaft half 11R is supported by the crankcase 5 via the right ball bearing 33, and this journal portion is adjacent to the right side of the right ball bearing 33. An oil pump drive gear 51 is attached. An oil pump 53 is provided below the right crankshaft half 11R, and an oil pump driven gear 52 meshed with the oil pump drive gear 51 is attached to the pump shaft 54 of the oil pump 53. . Therefore, the rotation of the crankshaft 11 is transmitted by the oil pump drive gear 51 and the oil pump driven gear 52, and the pump shaft 54 rotates to drive the oil pump 53.

  A portion of the right crankshaft half 11R on the right side of the oil pump drive gear 51 protrudes outward from the crankcase 5. Further, a stator 56 constituting a generator 55 is attached to the right outer side of the crankcase 5 by a bolt 58 so as to surround a journal portion of the right crankshaft half 11R protruding from the case 5. A rotor 57 constituting the generator 55 is disposed so as to be attached to the journal portion of the crankshaft half 11R and surround the outer peripheral portion of the stator 56. Therefore, when the crankshaft 11 is driven to rotate, the rotor 57 rotates around the stator 56, so that the generator 55 generates power. Note that an oil seal 59 is provided between the right crankshaft half 11R and the crankcase 5, and the lubricating oil supplied into the crankcase 5 does not flow out to the generator 55 side.

  Further, a cooling fan 60 is attached to the tip of the right crankshaft half 11R. The right side portion of the power unit 1 is covered with an engine cover 61, and an air intake hole 62 is formed on an extension line of the right crankshaft half body 11R of the engine cover 61. Therefore, when the crankshaft 11 is driven to rotate, outside air is taken into the engine cover 61 from the air intake hole 62 by the cooling fan 60, and passes through the cooling air passage 61 a surrounded by the engine cover 61 and the cylinder head 3 and the cylinder block. 4 is configured to flow around 4 to cool them.

  Now, the support structure of the crankshaft 11 in the power unit 1 configured as described above will be described with reference to FIGS. As described above, the left and right crankshaft halves 11L and 11R are supported by the crankcase 5 via the left and right ball bearings 32 and 33. These ball bearings 32 and 33 are provided by the left ball bearing 32. The right ball bearing 33 is fitted to and attached to the left bearing support hole 64 formed in the left wall portion 63 forming the crank chamber 5a from the right side, and the right ball bearing 33 is formed in the right wall portion 65 forming the crank chamber 5a. The support hole 66 is fitted and attached from the left side.

  In the right side wall portion 65 to which the right ball bearing 33 is attached, a portion diagonally below and behind the crankshaft 11 has an opening 67a on the outside and extends in the right direction, and is accommodated in communication with the right bearing support hole 66. A hole 67 is formed, and a bearing urging means 68 including a spring urging member 69 and a spring receiving member 70 is inserted and attached to the accommodation hole 67.

  The spring urging member 69 is formed in a cylindrical shape, and is inserted and attached to a frame 69a that can slide in the accommodation hole 67, and a spring mounting hole 69b that opens to the right end surface of the frame 69a and extends to the inside. And a spring 69c. A tapered surface 69d is formed at the left end of the top 69a. On the other hand, the spring receiving member 70 includes a screw portion 70a formed in a cylindrical shape and having a male screw formed on a circumferential surface thereof, and a flange portion 70b formed in a disk shape on the right end side. The spring urging member 69 is inserted into the accommodation hole 67 from the tapered surface 69d of the top 69a, and the screw portion 70a is screwed to the female screw formed on the inner peripheral surface of the opening 67a of the accommodation hole 67. A spring receiving member 70 is attached. A washer 71 is attached between the flange portion 70b and the right side wall portion 65.

  When the bearing urging means 68 is configured as described above, the tapered surface 69 d of the top 69 a inserted into the accommodation hole 67 contacts the lower right side of the outer ring 33 a constituting the right ball bearing 33. When the spring receiving member 70 is screwed into the accommodation hole 67, the spring 69c of the spring urging member 69 is pushed leftward by the spring receiving member 70, thereby pushing the top 69a rightward. Then, the outer ring 33 a of the right ball bearing 33 is elastically pushed up by the tapered surface 69 d of the top 69 in the direction of the rotation axis of the crankshaft 11, that is, the direction in which the outer ring 33 a is separated from the inner surface of the right bearing support hole 66. The impact of the sliding movement of the piston 9 can be absorbed by the spring 69c, and the right ball bearing 33 is stably supported.

  At this time, it is possible to prevent the lubricating oil in the crank chamber 5a from leaking to the generator 55 side by applying a sealer to and screwing the accommodating hole 67 and the threaded portion 72 of the spring receiving member 70. .

  In this way, the bearing urging means 68 is screwed into the housing hole 67 and the spring urging member 69 elastically pressing the right ball bearing 33, and the spring urging member 69 inserted into the housing hole 67. By comprising the spring receiving member 70 for receiving the spring 69c, it is not necessary to provide a bolt hole for pressing the spring urging member 69 separately from the accommodation hole 67. Can be reduced, and a compact configuration can be achieved. Further, the number of parts can be reduced because the spring plate support is not required. At this time, even if the space outside the right side wall portion 65 to which the right ball bearing 33 is attached is a dry space (a space to which no lubricant is supplied) provided with the cooling air passage 61a, the accommodation hole 67 and the spring receiving member 70 By applying a sealer to the threaded surfaces, the lubricating oil in the crank chamber 5a can be reliably sealed with a simple structure without complicating the structure.

  As shown in this embodiment, a generator support hole 72 for fixing the stator 56 of the generator 55 is formed in the right side wall portion 65 of the crankcase 5 in which the accommodation hole 67 is formed. If the stator 56 is mounted by screwing the bolts 58 into the support holes 72, the generator support holes 72 and the accommodation holes 67 can be processed in the same direction and with the same member. The cost can be reduced. Further, a supplementary drive unit for driving an auxiliary machine such as the oil pump 53, that is, the oil pump drive gear 51 is disposed on the side (right side) of the right ball bearing 33, so that the periphery of the accommodation hole 69 is provided. Thus, the oil pump drive gear 51 can be arranged in a compact manner.

  In the present embodiment, as shown in FIG. 2, the case where the accommodation hole 69 is formed on the opposite side of the piston 9 with respect to the axis of the crankshaft 11 has been described. You may arrange | position on the piston 9 side (position shown by the code | symbol 69 'in FIG. 2) with respect to an axis. When the air-fuel mixture burns in the combustion chamber 13, the force applied to the crankshaft 11 from the piston 9 acts rearward in FIG. For this reason, when arranged like the accommodation hole 69 ′, the direction in which the right ball bearing 33 is urged by the bearing urging means substantially coincides with the direction in which the piston 9 receives the explosion pressure. Can be suppressed.

  Further, the sealing method of the bearing urging means 68 is not limited to the method of applying a sealer to the screwing portion 72 as shown in FIG. 4A. For example, as shown in FIG. A ring groove 70c may be formed in the flange portion 70b of the receiving member 70 so as to surround the screw portion 70a, and an O-ring 74 may be attached to the ring groove 70c. In this case, when the spring receiving member 70 is screwed into the accommodation hole 67, the O-ring 74 is sandwiched between the outer surface of the crankcase 5 and the flange portion 70b, and the lubricating oil can be sealed. Further, as shown in FIG. 4C, a ring groove 70d may be formed on the side surface of the threaded portion 70a of the spring receiving member 70, and an O-ring 75 may be attached to the ring groove 70d. ), The inner periphery of the opening 67a of the accommodation hole 67 may be formed large, and the O-ring 76 may be disposed in this portion.

It is a top view of the power unit which has the support structure of the crankshaft which concerns on this invention. It is the side view which looked at the principal part of the above-mentioned power unit from the right side. It is sectional drawing which shows the principal part of a crankshaft support structure. It is explanatory drawing which shows the sealing method of a bearing biasing means, (a) is the structure which apply | coated the sealer to the screwing part, (b) is the structure which provided the O-ring in the flange part, (c) Is a configuration in which an O-ring is provided in the threaded portion, and (d) is a configuration in which an O-ring is provided in the opening of the accommodation hole.

Explanation of symbols

5 Crankcase 11 Crankshaft 33 Right ball bearing (bearing)
33a Outer ring 51 Oil pump drive gear (auxiliary drive unit)
53 Oil pump (auxiliary machine)
55 Generator 56 Stator 65 Right side wall (wall)
66 Right bearing support hole (bearing support hole)
67 Housing hole 67a Opening 68 Bearing urging means 69 Spring urging member 70 Spring receiving member 73 Generator mounting hole

Claims (4)

A bearing that is fitted in a bearing support hole provided in the crankcase and rotatably supports the crankshaft, and a bearing urging means that elastically presses the outer ring of the bearing away from the inner surface of the bearing support hole. A crankshaft support structure comprising:
The bearing urging means is
A spring receiving member fixed to the crankcase;
A spring biasing member that is biased and supported by the spring receiving member and engages with the outer ring of the bearing;
One end of the crankcase wall in which the bearing support hole is formed communicates with the bearing support hole, the spring biasing member is disposed, and the spring receiving member is fixed to the opening on the other end side. Providing a receiving hole for receiving the bearing urging means,
A support structure for a crankshaft configured such that the opening is sealed by the spring receiving member.   2. The generator according to claim 1, wherein a generator is disposed in a space on the side where the opening is formed across the wall, and a generator mounting hole for fixing a stator of the generator is provided in the vicinity of the accommodation hole. Crankshaft support structure.   3. The crankshaft support according to claim 1, wherein an accessory driving unit that drives an accessory is provided adjacent to the bearing on the crankshaft, and the receiving hole is provided around the accessory driving unit. Construction.   The crankshaft support structure according to any one of claims 1 to 3, wherein the bearing urging means is provided on a piston side with respect to an axis of the crankshaft.

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