JP2018162779A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine which can effectively prevent a deflection of a crank shaft supported by a slide bearing.SOLUTION: An internal combustion engine 29 incudes: a crank case 33 for defining a crank chamber 47; a case cover 93 for defining a space 92 between the crank cases 33 and fixed to the crank case 33; a crank shaft 32 having a crank 48 stored in the crank chamber 47, supported to the crank case 33 via slide bearings 49a, 49b, and penetrating the case cover 93; an oil seal 104 attached to the crank shaft 32 and closing a space between the crank shaft 32 and the case cover 93 around the crank shaft 32; and a rolling bearing 106 fitted in the case cover 93 on the side of the crank 48 of the oil seal 104 to rotatably support the crank shaft 32.SELECTED DRAWING: Figure 3

Description

  The present invention defines a space between a crankshaft supported by a crankcase via a sliding bearing and a crankcase, a case cover fixed to the crankcase, and a crankcase fitted into the case cover to rotate the crankshaft. The present invention relates to an internal combustion engine including a rolling bearing that is freely supported.

  Patent Document 1 discloses an internal combustion engine that supports a crankshaft with a pair of sliding bearings. The outer end of the crankshaft is accommodated in an oil sump closed by a crankcase cover. The crankshaft is supported by the rolling bearing in the oil sump. Rolling bearings prevent crankshaft runout.

  An oil passage is formed in the shaft of the crankshaft. Oil is supplied to the oil sump from the outer end of the crankshaft. The oil in the oil reservoir is used for lubricating the rolling bearing.

JP 2010-236499 A

  In the internal combustion engine described in Patent Document 1, a passage must be provided coaxially in the shaft of the crankshaft, which takes time for processing work. Moreover, since the oil sump is separated from the outer space by the crankcase cover, an auxiliary machine cannot be coupled to the outer end of the crankshaft.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an internal combustion engine that can effectively prevent the swing of a crankshaft supported by a slide bearing.

  According to the first aspect of the present invention, a crankcase that divides a crankcase, a case cover that divides a space between the crankcase and is fixed to the crankcase, and a crank that is accommodated in the crankcase. A crankshaft supported by the crankcase via a sliding bearing and penetrating the case cover; and attached to the crankshaft to block between the crankshaft and the case cover around the crankshaft An internal combustion engine including an oil seal and a rolling bearing that is fitted into the case cover on the crank side of the oil seal and rotatably supports the crankshaft is provided.

  According to the second aspect, in addition to the configuration of the first side, a generator is coupled to the crankshaft outside the case cover.

  According to the third aspect, in addition to the configuration of the first or second side surface, the sliding bearing and the rolling bearing engage with the cam chain in the space between the crankcase and the case cover. The sprocket is fixed.

  According to the fourth aspect, in addition to the structure of any one of the first to third aspects, an oil is provided between the slide bearing and the rolling bearing in the space between the crankcase and the case cover. The gear meshing with the pump is fixed.

  According to the fifth aspect, in addition to the configuration of the fourth side, the sprocket and the gear are integrally configured as one member.

  According to the sixth aspect, in addition to the configuration of any one of the first to fifth aspects, the case cover has an opening that can receive the oil seal from an outer space.

  According to the first aspect, oil is introduced into the crankcase and the space between the crankcase and the case cover. The oil seal prevents oil leakage from the space closed by the case cover. Since the rolling bearing is located closer to the crank side of the crankshaft than the oil seal, the rolling bearing is lubricated with oil. The oil passage in the shaft of the crankshaft can be omitted. In addition, since the crankshaft penetrates the case cover and protrudes into the outer space, an auxiliary machine can be coupled to the outer end of the crankshaft. Rolling bearings prevent crankshaft runout. The swing of the crankshaft supported by the slide bearing is effectively prevented.

  According to the second aspect, the rolling bearing can be disposed in proximity to the heavy generator. The crankshaft run-out based on the generator weight can be effectively prevented by the rolling bearing.

  According to the third aspect, the rolling bearing can be disposed close to a sprocket that receives a force from a cam chain that drives the cam. The swing of the crankshaft based on the driving force of the cam chain can be effectively prevented by the rolling bearing.

  According to the fourth aspect, the rolling bearing can be disposed in proximity to the drive gear that meshes with the driven gear that drives the oil pump. The swing of the crankshaft based on the driving of the oil pump can be effectively prevented by the rolling bearing.

  According to the fifth aspect, the assembly of the sprocket and the gear can be simplified.

  According to the sixth aspect, the oil seal can be easily assembled.

1 is a side view schematically showing a scooter type motorcycle according to an embodiment of a saddle-ride type vehicle. FIG. 2 is a horizontal sectional view taken along line 2-2 in FIG. It is an expanded sectional view showing the composition of a crankcase roughly.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, front and rear, up and down, and left and right directions refer to directions viewed from a passenger on a motorcycle.

  FIG. 1 schematically shows a scooter type motorcycle according to an embodiment of a saddle type vehicle. The motorcycle 11 includes a body frame 12 and a body cover 13. The vehicle body frame 12 includes a head pipe 14 at the front end, a main frame 15 coupled to the head pipe 14 at the front end, a cross pipe 16 coupled to the rear portion of the main frame 15 and extending in the vehicle width direction, and the cross pipe 16 And a pair of left and right rear frames 17 extending in the vehicle front-rear direction. The head pipe 14 supports a front fork 18 that supports the front wheel WF so as to be rotatable about a horizontal axis, and a rod-shaped steering handle 19 that can be steered.

  The vehicle body cover 13 is attached to the vehicle body frame 12. An occupant seat 21 is mounted on the vehicle body cover 13 above the rear frame 17. The body cover 13 includes a front cover 22 that covers the head pipe 14 from the front, a leg shield 23 that is continuous from the front cover 22, and a main frame 15 between the passenger seat 21 and the front wheel WF that is continuous from the lower end of the leg shield 23. And a step floor 24 disposed above.

  A unit swing type drive unit 25 is disposed in a space below the rear frame 17. The drive unit 25 is coupled to a bracket 26 coupled to the front end of the rear frame 17 via a link 27 so as to be swingable in the vertical direction. A rear wheel WR is supported at the rear end of the drive unit 25 so as to be rotatable about a horizontal axis. A rear cushion unit 28 is disposed between the rear frame 17 and the drive unit 25 at a position away from the link 27 and the bracket 26. The drive unit 25 includes an air-cooled single-cylinder internal combustion engine 29 and a transmission 31 that is connected to the internal combustion engine 29 and the rear wheel WR and transmits the output of the internal combustion engine 29 to the rear wheel WR. A transmission case 31 a of the transmission device 31 is coupled to the engine body 29 a of the internal combustion engine 29.

  An engine main body 29a of the internal combustion engine 29 includes a crankcase 33 that supports a crankshaft 32 so as to be rotatable about a rotation axis, a cylinder block 34 coupled to the crankcase 33, and a cylinder head 35 coupled to the cylinder block 34. And a head cover 36 coupled to the cylinder head 35. An intake device 37 and an exhaust device 38 are connected to the cylinder head 35. The intake device 37 includes an air cleaner 39 supported by the transmission case 31 a and a throttle body 41 disposed between the air cleaner 39 and the cylinder head 35. A fuel injection valve 42 is attached to the upper side wall of the cylinder head 35. The exhaust device 38 includes an exhaust pipe 43 extending rearward from the lower side wall of the cylinder head 35 through the lower part of the engine body 29a, and an exhaust muffler (not shown) connected to the downstream end of the exhaust pipe 43 and coupled to the crankcase 33. Z)).

  As shown in FIG. 2, a cylinder bore 44 is defined in the cylinder block 34. A piston 45 is fitted into the cylinder bore 44 so as to be slidable along the cylinder axis C. The cylinder axis C is slightly inclined upward. The crankshaft 32 is connected to the piston 45. The rotation axis Xis of the crankshaft 32 is directed in the vehicle width direction.

  A combustion chamber 46 is defined in the cylinder head 35. The combustion chamber 46 continues from the cylinder bore 44. The piston 45 faces the cylinder head 35 and partitions the combustion chamber 46 between the piston 45 and the cylinder head 35. An air-fuel mixture is introduced into the combustion chamber 46 via an intake device 37. The exhaust gas in the combustion chamber 46 is discharged through the exhaust device 38.

  The crankcase 33 is divided into a first case half 33a and a second case half 33b. The first case half 33a and the second case half 33b cooperate to partition the crank chamber 47. A crank 48 of the crankshaft 32 is accommodated in the crank chamber 47. The first case half 33 a has a sliding bearing 49 a that rotatably supports the crankshaft 32, while the second case half 33 b has a sliding bearing 49 b that rotatably supports the crankshaft 32.

  An AC generator starter 50 is coupled to the crankcase 33. The alternator starter 50 includes an outer rotor 51 fixed to the crankshaft 32 that passes through the first case half 33a of the crankcase 33 and protrudes from the first case half 33a, and is surrounded by the outer rotor 51. 32 and an inner stator 52 disposed around 32. The inner stator 52 is fixed to a support plate 53 fastened to the first case half 33a. An electromagnetic coil 52 a is wound around the inner stator 52. A magnet 51 a is fixed to the outer rotor 51. When the outer rotor 51 rotates relative to the inner stator 52, electric power is generated by the electromagnetic coil 52a. On the other hand, when a current flows through the electromagnetic coil 52a, a magnetic force is generated in the electromagnetic coil 52a, causing the outer rotor 51 to rotate.

  A cylindrical generator cover 54 surrounding the AC generator starter 50 is coupled to the first case half 33a. An air inlet 54 a is defined at the open end of the generator cover 54. A radiator 55 is disposed at the air inlet 54a. A cooling fan 56 is coupled to the outer surface of the outer rotor 51. The cooling fan 56 rotates in accordance with the rotation of the crankshaft 32, and the cooling air flows through the radiator 55.

  The transmission device 31 is housed in a transmission case 31a, and an electronically controlled V-belt continuously variable transmission (hereinafter referred to as "transmission") 57 that continuously changes the rotational power transmitted from the crankshaft 32, and a transmission A reduction gear mechanism 59 that is housed in the case 31a and decelerates the rotational power of the transmission 57 and transmits it to the axle 58 of the rear wheel WR. The rear wheel WR is disposed between the transmission case 31 a and the support arm 61. The support arm 61 extends continuously from the crankcase 33 toward the rear of the vehicle. The aforementioned exhaust muffler is attached to the support arm 61. The axle 58 of the rear wheel WR is supported at both ends by the transmission case 31a and the support arm 61 so as to be rotatable about the axis.

  The transmission case 31 a includes a case main body 62 that is continuous from the second case half 33 b of the crankcase 33, a case cover 64 that is fastened to the case main body 62 and divides the transmission chamber 63 between the case main body 62, A gear cover 66 is provided that is fastened to the case main body 62 and defines a gear chamber 65 between the case main body 62 and the case main body 62. A transmission 57 is accommodated in the transmission chamber 63. A reduction gear mechanism 59 is accommodated in the gear chamber 65. The case main body 62 and the case cover 64 together constitute a mission case.

  The transmission 57 is disposed in the transmission chamber 63 and is installed in the transmission chamber 63 and the drive pulley device 67 attached to the crankshaft 32 as a drive shaft. The transmission chamber 63 is moved from the transmission chamber 63 to the gear chamber 65. And a driven pulley device 69 attached to the protruding driven shaft 68. In the drive pulley device 67, a fixed sheave 73 fixed to the crankshaft 32 and a movable sheave 74 supported by the crankshaft 32 so as to be movable in the axial direction of the crankshaft 32 while facing the fixed sheave 73. The V belt 71 is wound around. Similarly, in the driven pulley device 69, a V-belt 71 is provided between a fixed sheave 78 that is coaxially mounted on the driven shaft 68 and a movable sheave 79 that is coaxially mounted on the driven shaft 68 while facing the fixed sheave 78. Is wrapped around. The belt pulley diameter is variably electronically controlled in the drive pulley device 67 by the action of the actuator unit 72. The belt winding diameter of the driven pulley device 69 changes according to the change in the belt winding diameter of the driving pulley device 67.

  In the drive pulley device 67, the movable sheave 74 is disposed between the second case half 33 b of the crankcase 33 and the fixed sheave 73. The movable sheave 74 has a movable sheave boss 74 a that receives the crankshaft 32. The movable sheave boss 74 a extends from the sheave body that receives the V-belt 71 toward the second case half 33 b of the crankcase 24. The transmission 57 includes a first shift mechanism 75a including a centrifugal weight and a cam plate, and a second shift mechanism 75b including the actuator unit 72 described above. In accordance with the functions of the first shift mechanism 75a and the second shift mechanism 75b, the axial movement of the movable sheave 74 is realized, and the winding radius of the V-belt 71 changes.

  The driven pulley device 69 has a cylindrical shape coaxial with the driven shaft 68, and has an inner cylinder 76 attached to the coaxial driven shaft 68, a cylindrical shape coaxial with the driven shaft 68, and coaxially with the inner cylinder 76. And an outer cylinder 77 to be mounted. The inner cylinder 76 is supported by the driven shaft 68 so as to be relatively rotatable. The outer cylinder 77 is supported by the inner cylinder 76 so as to be relatively rotatable and axially displaceable. A fixed sheave 78 is coaxially fixed to the inner cylinder 76. The inner cylinder 76 and the fixed sheave 78 are integrally formed from a material lighter than steel, such as aluminum. A movable sheave 79 is coaxially fixed to the outer cylinder 77. The outer cylinder 77 and the movable sheave 79 are integrally formed from a material lighter than steel, such as aluminum. The movable sheave 79 approaches or moves away from the fixed sheave 78 in accordance with the axial relative displacement of the outer cylinder 77 and the inner cylinder 76.

  A centrifugal clutch 81 is attached to the driven shaft 68. The centrifugal clutch 81 includes a clutch plate 81 a fixed to the inner cylinder 76. A string spring 82 is disposed between the clutch plate 81a and the movable sheave 79. The string spring 82 exerts an elastic force that presses the movable sheave 79 toward the fixed sheave 78. When the winding radius of the V belt 71 is increased by the driving pulley device 67, the movable sheave 79 is moved away from the fixed sheave 78 against the elastic force of the string winding spring 82 in the driven pulley device 69, and the winding radius of the V belt 71 is decreased. .

  The centrifugal clutch 81 includes an outer plate 81 b that is fixed to the driven shaft 68. The outer plate 81b is opposed to the clutch plate 81a. When the clutch plate 81a rotates, the outer plate 81b is coupled to the clutch plate 81a by the action of centrifugal force. Thus, the rotation of the driven pulley device 69 is transmitted to the driven shaft 68. When the engine speed exceeds the set speed, the centrifugal clutch 81 establishes a power transmission state.

  The reduction gear mechanism 59 is disposed between the drive gear 83 fixed to the driven shaft 68 protruding into the gear chamber 65, the final gear 84 fixed to the axle 58 of the rear wheel WR, and the drive gear 83 and the final gear 84. Idle gears 85a and 85b. The idle gears 85a and 85b are fixed to a common intermediate shaft 86. The drive gear 83 meshes with the idle gear 85a, and the final gear 84 meshes with the idle gear 85b. Thus, the rotation of the driven shaft 68 is decelerated and transmitted to the axle 58 of the rear wheel WR.

  As shown in FIG. 3, the crank 48 of the crankshaft 32 includes a disc-shaped first crank web 87 having a first shaft 87a, and a circle having a second shaft 88a coupled to the first crank web 87. A plate-shaped second crank web 88 and a crank pin 89 that connects the first crank web 87 and the second crank web 88 to each other while coaxially arranging the first shaft 87a and the second shaft 88a. The axial center of the crankpin 89 is disposed at a position displaced from the rotational axis Xis of the crankshaft 37. The tip of a connecting rod 91 is connected to the crankpin 89 so as to be rotatable around a rotation axis parallel to the axis of the first shaft 87a and the second shaft 88a.

  The first crank web 87 has a counterweight 87 b on the surface facing the second crank web 88. Similarly, the second crank web 88 has a counterweight 88 b on the surface facing the first crank web 87. The weight balance of the crank 48 is adjusted by the action of the counterweights 87b and 88b. The position of the center of gravity of the crank 48 is set on the rotation axis Xis of the crankshaft 32. The rotation of the crankshaft 32 during rotation is minimized by the action of the counterweights 87b and 88b.

  A case cover 93 that divides the cam chain chamber (space) 92 is attached to the first case half 33a of the crankcase 33 with respect to the outer surface of the first case half 33a. The case cover 93 is fixed to the crankcase 33 in a liquid-tight manner. The crankshaft 32 protruding from the sliding bearing 49 a of the crankcase 33 passes through the case cover 93 and is coupled to the alternator starter 50 outside the case cover 93.

  A first oil passage 94a for supplying oil to the sliding bearing 49a is formed in the first case half 33a. A second oil passage 94b for supplying oil to the slide bearing 49b is formed in the second case half 33b. The second oil passage 94b branches from the first oil passage 94a. An oil filter 95 is connected to the first oil passage 94a. An oil pump 96 is connected to the oil filter 95 through a third oil passage 94c.

  The oil pump 96 is attached to the outer surface of the crankcase 33 in the cam chain chamber 92. A driven gear 97 is coupled to the oil pump 96. The driven gear 97 meshes with a drive gear 98 fixed to the crankshaft 32 in the cam chain chamber 92. The oil pump 96 operates according to the driving force of the crankshaft 32 via the driving gear 98 and the driven gear 97. The oil in the cam chain chamber 92 is supplied to the oil filter 95 by the action of the oil pump 96. The oil filtered by the oil filter 95 is supplied to the individual slide bearings 49a and 49b from the first oil passage 94a and the second oil passage 94b.

  The internal combustion engine 29 includes a valve operating mechanism 99 disposed in the cam chain chamber 92. The valve mechanism 99 includes a cam sprocket (not shown) fixed to a camshaft (not shown), a sprocket 101 fixed to the crankshaft 32, a cam sprocket and a cam chain 102 wound around the sprocket 101. Is provided. The sprocket 101 meshes with the cam chain 102 and transmits the rotational force of the crankshaft 32 to the camshaft to drive the cam.

  Here, the sprocket 101 and the drive gear 98 are integrally formed on one cylindrical body 103. The cylinder 103 is attached to the crankshaft 32. The cylinder 103 may be splined to the crankshaft 32. The cylinder 103 is fixed on the crankshaft 32 by a stopper 103a that is screwed to the crankshaft 32.

  The internal combustion engine 29 includes an oil seal 104 that is attached to the crankshaft 32 outside the first case half 33a and closes the crankshaft 32 and the case cover 93 around the crankshaft 32. The oil seal 104 is fitted into the opening 105 of the case cover 93. The opening 105 defines, for example, a cylindrical space coaxial with the rotation axis Xis of the crankshaft 32. The oil seal 104 can be fitted into the opening 105 from the front end side of the crankshaft 32.

  The internal combustion engine 29 includes a rolling bearing 106 that is fitted into a case cover 93 on the crank 48 side of the oil seal 104 and rotatably supports the crankshaft 32. The rolling bearing 106 is formed in the case cover 93 on the crank 48 side of the opening 105, and is fitted into a fitting port 108 connected to the opening 105 at a step 107. Therefore, the rolling bearing 106 has an outer diameter larger than the outer diameter of the oil seal 104. The sprocket 101 and the drive gear 98 are disposed in the cam chain chamber 92 between the sliding bearing 49 a and the rolling bearing 106.

  The internal combustion engine 29 further includes an oil seal 109 that is fitted into the second case half 33b outside the sliding bearing 49b. The oil seal 109 closes between the crankshaft 32 and the second case half 33b around the crankshaft 32. The oil is confined in the crank chamber 47 and the cam chain chamber 92 by the action of the two oil seals 104 and 109.

  Next, the operation of this embodiment will be described. During rotation of the crankshaft 32, the rolling bearing 106 prevents the crankshaft 32 from swinging. The swing of the crankshaft 32 supported by the slide bearings 49a and 49b is effectively prevented. Oil is introduced into the crankcase 33 and the cam chain chamber 92. The oil seal 104 prevents oil leakage from the space closed by the case cover 93. Since the rolling bearing 106 is located closer to the crank 48 of the crankshaft 32 than the oil seal 104, the rolling bearing 106 is lubricated with oil. The oil passage in the shaft of the crankshaft 32 is omitted. In addition, since the crankshaft 32 passes through the case cover 93 and protrudes into the outer space, the alternator starter 50 is coupled to the outer end of the crankshaft 32.

  In the present embodiment, the rolling bearing 106 is disposed close to the AC generator starter 50 having a weight. The swing of the crankshaft 32 based on the weight of the alternator starter 50 is effectively prevented by the rolling bearing 106. The sprocket 101 is fixed between the sliding bearing 49 a and the rolling bearing 106 in the cam chain chamber 92. The rolling bearing 106 is disposed close to the sprocket 101 that receives a force from the cam chain 102 that drives the cam. The swing of the crankshaft 32 based on the driving force of the cam chain 102 is effectively prevented by the rolling bearing 106. In addition, a drive gear 98 that meshes with the oil pump 96 is fixed between the sliding bearing 49 a and the rolling bearing 106 in the cam chain chamber 92. The rolling bearing 106 is disposed in the vicinity of a drive gear 98 that meshes with a driven gear 97 that drives the oil pump 96. The swing of the crankshaft 32 based on the drive of the oil pump 96 is effectively prevented by the rolling bearing 106.

  As described above, the sprocket 101 and the drive gear 98 are integrally configured as one member. Therefore, the assembly of the sprocket 101 and the drive gear 98 is simplified. Moreover, the case cover 93 has an opening 105 that can receive the oil seal 104 from the outer space. The oil seal 104 can be easily assembled.

  DESCRIPTION OF SYMBOLS 29 ... Internal combustion engine, 32 ... Crankshaft, 33 ... Crank case, 47 ... Crank chamber, 48 ... Crank, 49a ... Sliding bearing, 49b ... Sliding bearing, 50 ... Generator (alternator starter) 92 ... Space (cam chain) Chamber), 93 ... case cover, 96 ... oil pump, 98 ... gear (drive gear), 101 ... sprocket, 102 ... cam chain, 104 ... oil seal, 105 ... opening, 106 ... rolling bearing.

Claims (6)

A crankcase (33) defining a crankcase (47);
A case cover (93) that partitions the space (92) between the crankcase (33) and is fixed to the crankcase (33);
A crankshaft having a crank (48) accommodated in the crank chamber (47), supported by the crankcase (33) via sliding bearings (49a, 49b) and penetrating the case cover (93) ( 32)
An oil seal (104) mounted on the crankshaft (32) and closing the space between the crankshaft (32) and the case cover (93) around the crankshaft (32);
An internal combustion engine comprising: a rolling bearing (106) which is fitted into the case cover (93) on the crank (48) side of the oil seal (104) and rotatably supports the crankshaft (32). organ.   2. The internal combustion engine according to claim 1, wherein a generator (50) is coupled to the crankshaft (32) outside the case cover (93).   The internal combustion engine according to claim 1 or 2, wherein the sliding bearing (49a) and the rolling bearing (106) are disposed in a space (92) between the crankcase (33) and the case cover (93). An internal combustion engine characterized in that a sprocket (101) meshing with the cam chain (102) is fixed therebetween.   The internal combustion engine according to any one of claims 1 to 3, wherein the sliding bearing (49a) and the rolling bearing in a space (92) between the crankcase (33) and the case cover (93). An internal combustion engine characterized in that a gear (98) meshing with the oil pump (96) is fixed between (106).   The internal combustion engine according to claim 4, wherein the sprocket (101) and the gear (98) are integrally formed as one member. The internal combustion engine according to any one of claims 1 to 5, wherein the case cover (93) has an opening (105) capable of receiving the oil seal (104) from an outer space. organ.