JP2009287505A - Power unit for motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a degree of freedom in arrangement of a part arranged in an upper end part of an engine body, by miniaturizing the engine body in the cylinder axial direction, in a power unit for a motorcycle for mounting the engine body of an engine having a valve gear capable of changing an operation mode of an engine valve and a valve system control device for controlling operation of the valve gear, on a vehicle body frame, and storing a transmission in a crankcase of the engine body. <P>SOLUTION: This power unit for the motorcycle is characterized by installing the valve system control device 81 on a rear surface of the crankcase 26. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  According to the present invention, an engine main body of an engine having a valve operating device capable of changing an operation mode of the engine valve and a valve operating control device for controlling the operation of the valve operating device is mounted on a vehicle body frame, The present invention relates to a motorcycle power unit in which a transmission is housed in a crankcase.

Patent Document 1 discloses that a valve operating control device for changing an operation mode of a valve operating device is provided on a head cover in an engine body.
JP 2003-003811 A

  However, in the configuration in which the valve control device is provided in the head cover as disclosed in Patent Document 1, the engine body is enlarged in the direction along the cylinder axis. In particular, as disclosed in Patent Document 1, when the axis of the electric motor included in the valve control apparatus is set in a direction along the cylinder axis, the engine body becomes larger in the cylinder axis direction, and the engine When the fuel tank is arranged above the main body, the vertical position of the fuel tank also rises, and the motorcycle becomes large in the vertical direction. In addition, the head cover may be provided with an insertion hole for inserting the spark plug, and in order to ensure the maintainability of the spark plug, it is necessary to consider that the valve control device and the insertion hole do not overlap. There is a limitation in the arrangement of the valve control device.

  The present invention has been made in view of such circumstances, and is capable of reducing the size of the engine body in the cylinder axial direction and automatically increasing the degree of freedom in arrangement of components disposed at the upper end of the engine body. An object is to provide a power unit for a motorcycle.

  In order to achieve the above object, an invention according to claim 1 is an engine of an engine having a valve operating device capable of changing an operation mode of an engine valve and a valve operating control device for controlling the operation of the valve operating device. In a motorcycle power unit in which a main body is mounted on a vehicle body frame and a transmission is housed in a crankcase of the engine main body, the valve control device is attached to a rear surface of the crankcase.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, a swing arm that pivotally supports a rear wheel can swing on a pair of left and right pivot plates provided in the vehicle body frame via the support shaft. The valve control device is arranged in front of the support shaft.

  The invention according to claim 3 is characterized in that, in addition to the configuration of the invention according to claim 2, the valve operating control device is arranged above the support shaft.

  According to a fourth aspect of the invention, in addition to the configuration of the second or third aspect of the invention, the valve operating control device is disposed between the pair of pivot plates in a plan view.

  According to a fifth aspect of the invention, in addition to the configuration of the fourth aspect of the invention, the valve operating control device is arranged at a position overlapping the pivot plate in a side view.

  According to a sixth aspect of the invention, in addition to the configuration of the first aspect of the invention, the plurality of valve control devices are symmetrical with respect to a vehicle body centerline extending forward and backward through the widthwise center of the vehicle body frame. It is characterized by being arranged.

  In addition to the configuration of the invention according to any one of claims 1 to 6, the invention according to claim 7 is configured so that the longitudinal direction of the driving means provided in the valve operating control device is along the rear surface of the crankcase. The valve operating control device is attached to the rear surface of the crankcase.

  The intake valve 46 and the exhaust valve 47 of the embodiment correspond to the engine valve of the present invention, and the electromagnetic on-off valve 85 of the embodiment corresponds to the driving means of the present invention.

  According to the first aspect of the present invention, since the valve operating control device is attached to the rear surface of the crankcase, it is possible to reduce the size of the engine in the cylinder axial direction, and the components disposed at the upper end of the engine body. The degree of freedom in arrangement can be increased. In addition, the crankcase can effectively prevent flying stones, muddy water, and the like from the front from hitting the valve controller.

  According to the second aspect of the present invention, since the valve operating control device is disposed in front of the support shaft that swingably supports the swing arm on the pivot plate, the dead space between the support shaft and the crankcase is effectively made effective. It is possible to arrange the valve control device by using it.

  According to the invention described in claim 3, since the valve operating control device is disposed in front of and above the support shaft, it is effective at the front portion of the swing arm that stepping stones, muddy water, etc. from below hit the valve operating control device. Can be suppressed.

  According to the fourth aspect of the present invention, it is possible to arrange the valve operating control device by effectively utilizing the dead space between the pivot shaft and the crankcase and between the pivot plates.

  According to the fifth aspect of the present invention, since the valve control device is arranged at a position overlapping the pivot plate in a side view, the pivot plate effectively prevents the stepping stones from the side from hitting the valve control device. can do.

  According to the sixth aspect of the present invention, since the plurality of valve control devices are symmetrically arranged on both sides of the vehicle body center line, the weight of the power unit is biased to the left or right with respect to the vehicle body center line. Can be prevented.

  According to the seventh aspect of the present invention, since the longitudinal direction of the drive means provided in the valve operating control device is along the rear surface of the crankcase, the rearward drive of the drive means from the rear surface of the crankcase is suppressed, and the front and rear of the engine An increase in length can be avoided. In addition, the front and rear length of the motorcycle can be shortened by bringing the parts behind the engine closer to the rear side of the crankcase.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 6 show an embodiment of the present invention. FIG. 1 is a left side view of a motorcycle, FIG. 2 is a partially cutaway side view of a power unit viewed from the left side, and FIG. FIG. 4 is a sectional view taken along the line 4-4 in FIG. 2, FIG. 5 is a longitudinal sectional view of the intake side valve operating mode changing mechanism, and FIG. FIG. 6 is a sectional view taken along line 6-6.

  First, in FIG. 1, a body frame F of a motorcycle includes a head pipe 13 that pivotally supports a front fork 11 and a steering handle 12 that pivotally support a front wheel WF, and a pair of left and right that extends rearwardly downward from the head pipe 13. Main frames 14, a pair of left and right engine hangers 15 extending downward from the main frame 14, and the head pipe 13 and the front portions of the main frames 14, and extending downward from the rear portions of the main frames 14. A pair of left and right pivot plates 16 and a pair of left and right seat rails 17 extending rearward and connected to the rear portions of the main frames 14 are provided.

  A front part of a swing arm 18 that pivotally supports the rear wheel WR is supported on the pivot plate 16 so as to be swingable up and down via a support shaft 107. Between the swing arm 18 and the lower part of the pivot plate 16 is supported. A link mechanism 19 is provided, and a rear cushion unit 20 is provided between a member constituting a part of the link mechanism 19 and the upper portion of the pivot plate 16.

  A power unit P is mounted on the body frame F between the front wheel WF and the rear wheel WR, and an output shaft 21 of the power unit P is linked and connected to the rear wheel WR via a chain transmission means 22. Thus, the chain transmission means 22 includes a drive sprocket 108 fixed to the output shaft 21, a driven sprocket 109 fixed to the rear wheel WR, and an endless shape wound around the drive sprocket 108 and the driven sprocket 109. Chain 110.

  Further, a fuel tank 23 is mounted on the main frame 14... Above the power unit P, and a riding seat 24 disposed behind the fuel tank 23 is supported by the seat rail 17.

  2 and 3, the power unit P includes an engine E that is, for example, a four-cylinder in-line multicylinder, and a transmission M that changes the output of the engine E stepwise. The main body 25 includes a crankcase 26 that rotatably supports a crankshaft 30 having an axis along the width direction of the body frame F, a cylinder block 27 that is coupled to the front upper portion of the crankcase 26, A cylinder head 28 to be coupled and a head cover 29 coupled to the cylinder head 28 are provided.

  The crankcase 26 is formed by connecting an upper crankcase half 26a and a lower crankcase half 26b to each other, and the cylinder block 27 is formed integrally with the upper crankcase half 26a.

  At the front of the cylinder block 27 are provided brackets 31 attached to the lower part of the engine hanger 15, and the upper part of the upper case half 26 a of the crankcase 26 is provided at the upper part of the pivot plate 16. Are provided at the rear lower portion of the lower case half 26b of the crankcase 26, and brackets 33 are provided at the lower portion of the pivot plate 16. In addition, a starter motor 105 capable of applying a starting rotational power to the crankshaft 30 is disposed at the front lower portion of the cylinder block 27.

  The transmission M is provided with a gear train of a plurality of shift stages that can be alternatively established between an input shaft 35 to which rotational power is transmitted from the crankshaft 30 and the output shaft 21. The input shaft 35 and the output shaft 21 are accommodated in the crankcase 26 on the rear side of the crankshaft 30 with the axes of the input shaft 35 and the output shaft 21 being parallel to the axis of the crankshaft 30.

  In FIG. 4, the cylinder block 27 is provided with four cylinder bores 36A, 36B, 36C, and 36D arranged in parallel in the direction along the axis of the crankshaft 30, and the cylinder axis C of the cylinder bores 36A to 36D. Is inclined upward. Pistons 37 are slidably fitted to the cylinder bores 36A to 36D, and the pistons 37 are connected to the crankshaft 30 via connecting rods 38.

  Between the cylinder block 27 and the cylinder head 28, combustion chambers 39 are formed for each cylinder so as to face the tops of the pistons 37 slidably fitted into the cylinder bores 36A to 36D. The cylinder head 28 is provided with an intake port 40 and an exhaust port 41 that can communicate with the combustion chambers 39 for each cylinder. The intake port 40 is opened on a rear side surface of the cylinder head 28 and the exhaust port 40 is opened. The ports 41 are opened on the front side surface of the cylinder head 28.

  An intake device 42 is connected to the rear side surface of the cylinder head 28. The intake device 42 is disposed above the throttle bodies 43, which are individually connected to the intake ports 40, and the throttle bodies 43, respectively. And an air cleaner 44 to which the throttle bodies 43 are connected in common. Each throttle body 43 is provided with a combustion injection valve 45 for injecting fuel toward the intake port 40. The air cleaner 44 is disposed so as to be covered with the fuel tank 23 as shown in FIG.

  The cylinder head 28 is provided with a pair of engine valves 46 for each cylinder and a pair of exhaust valves 47 so as to be openable and closable. Each of the intake valves 46 is a valve spring 48. The exhaust valves 47 are energized in the valve closing direction by the valve springs 49, respectively.

  A valve operating device 50 for opening and closing the intake valves 46 and the exhaust valves 47 is accommodated between the cylinder head 28 and the head cover 29. The valve operating device 50 includes an intake side camshaft 51 and an exhaust side cam. An intake side valve lifter 54 interposed between the shaft 52, an intake side valve cam 53 provided on the intake side camshaft 51 and an intake valve 46, and an exhaust side cam 55 provided on the exhaust side camshaft 52. , And exhaust valves 47, and exhaust side valve lifters 56 interposed therebetween.

  The intake side camshaft 51 and the exhaust side camshaft 52 are rotatably supported by a holder 59 fastened to the cylinder head 28 and a cam holder 60 fastened to the holder 59. A timing transmission device 116 using an endless cam chain 115 is provided between the exhaust camshaft 52 and the crankshaft 30, and rotational power from the crankshaft 30 causes the timing transmission device 116 to pass through. To the intake side camshaft 51 and the exhaust side camshaft 52 at a reduction ratio of 1/2. The intake side valve lifters 54 and the exhaust side valve lifters 56 are slidably fitted to the holder 59.

  By the way, the cylinders at both ends along the cylinder arrangement direction among the in-line four cylinders are cylinders that can be in a cylinder deactivation state, and the two cylinders at the center along the cylinder arrangement direction are cylinders that are always operated during operation of the engine. And the intake valve lifters 54 and the exhaust valve lifters 56 corresponding to the cylinders at both ends in the cylinder arrangement direction of the valve operating device 50 are closed and stopped. Thus, intake side and exhaust side valve operation mode changing mechanisms 57..., 58.

  In FIG. 5, the intake side valve operation mode changing mechanism 57 forms a hydraulic chamber 62 between the pin holder 61 slidably fitted to the intake side valve lifter 54 and the inner surface of the intake side valve lifter 54 to form the pin holder 61. And a return spring provided between the slide pin 63 and the pin holder 61 by exerting a spring force that urges the slide pin 63 in a direction to reduce the volume of the hydraulic chamber 62. 64 and a stopper pin 65 that engages with the slide pin 63 and is inserted into the pin holder 61 so as to prevent rotation of the slide pin 63 around the axis.

  An annular groove 66 is provided on the outer periphery of the pin holder 61 and has a bottomed sliding hole having an axis perpendicular to the axis of the intake valve lifter 54 and having one end opened to the annular groove 66 and the other end closed. 67 is provided on the pin holder 61. The pin holder 61 has an insertion hole 68 through which the tip of the stem 46 a of the intake valve 46 urged by the valve spring 48 in the valve closing direction is inserted, and an extension that sandwiches the sliding hole 67 between the insertion hole 68. A hole 69 is provided coaxially so as to be able to accommodate the tip of the stem 46a of the intake valve 46. A disc-shaped shim 70 that closes the end of the extension hole 69 on the closed end side of the valve lifter 42 is fitted into the pin holder 61, and a protrusion 71 that contacts the shim 70 is integrated with the central portion of the closed end inner surface of the intake side valve lifter 54. Is provided.

  A slide pin 63 is slidably fitted in the slide hole 67 of the pin holder 61. A hydraulic chamber 62 communicating with the annular groove 66 is formed between one end of the slide pin 63 and the inner surface of the intake side valve lifter 54, and is formed between the other end of the slide pin 63 and the closed end of the slide hole 67. A return spring 64 is accommodated in the spring chamber 72.

  An accommodation hole 73 that can be coaxially connected to the insertion hole 68 and the extension hole 69 is provided in the intermediate portion in the axial direction of the slide pin 63 so as to accommodate the distal end portion of the stem 46a, and the insertion hole 73 side of the accommodation hole 73 is provided. This end is opened to a flat contact surface 74 formed on the lower outer surface of the slide pin 63 so as to face the insertion hole 68. Thus, the contact surface 74 is formed relatively long along the axial direction of the slide pin 63, and the accommodation hole 73 is opened at a portion of the contact surface 74 on the hydraulic chamber 62 side.

  Such a slide pin 63 balances the hydraulic pressure acting on one end side of the slide pin 63 by the hydraulic pressure of the hydraulic chamber 62 and the spring force acting on the other end side of the slide pin 63 by the return spring 64. When the hydraulic pressure in the hydraulic chamber 62 is low, the receiving hole 73 is displaced from the axis of the insertion hole 68 and the extension hole 69 so that the tip of the stem 46a comes into contact. The tip of the stem 46a inserted through the insertion hole 68 is moved to the right side of FIG. The portion is moved to the left side of FIG. 5 so as to be accommodated in the accommodation hole 73 and the extension hole 69.

  Thus, when the slide pin 63 moves to a position where the accommodation hole 73 is coaxially connected to the insertion hole 68 and the extension hole 69, the intake side valve lifter 54 slides due to the pressing force acting from the intake side cam 53. In response to this, the pin holder 61 and the slide pin 63 also move to the intake valve 46 side together with the intake side valve lifter 54. However, the intake side valve lifter 54 and the pin holder are merely accommodated in the accommodation hole 73 and the extension hole 52 of the stem 46a. No pressing force in the valve opening direction acts on the intake valve 46 from 61, and the intake valve 46 remains at rest. Further, when the slide pin 63 moves to a position where the tip end portion of the stem 46 a comes into contact with the contact surface 74, the pin holder corresponding to the intake side valve lifter 54 sliding by the pressing force acting from the intake side cam 53. Since the pressing force in the valve opening direction acts on the intake valve 46 as the 61 and the slide pin 63 move to the intake valve 46 side, the intake valve 46 opens and closes according to the rotation of the intake side cam 53.

  A holder 59 attached to the cylinder head 28 is provided with a support hole 76 in which the intake side valve lifter 54 is fitted so as to slidably support the intake side valve lifter 54. On the inner surface, annular recesses 77 are provided so as to surround the intake side valve lifters 54, and the intake side valve lifters 54 are provided regardless of sliding in the support holes 76 of the intake side valve lifters 54. A plurality of communication holes 78 for communicating the annular recesses 77 with the annular grooves 66 are provided. Between the intake side valve lifters 54 and the cylinder head 28, there are provided springs 80 for urging the intake side valve lifters 54 in a direction to contact the intake side cams 53.

  The exhaust side valve operation mode changing mechanism 58 incorporated in the exhaust side valve lifters 56 is also configured in the same manner as the intake side valve operation mode changing mechanism 57 described above, and closes the exhaust valve 47 when high pressure oil pressure is applied. It is possible to switch between a state of resting and a state of opening / closing the exhaust valves 47 when the acting hydraulic pressure decreases.

  That is, the valve operating device 50 performs intake control of portions corresponding to the cylinders at both ends along the cylinder arrangement direction among the in-line four cylinders by the operation control of the intake side valve operation mode change mechanism 57... And the exhaust side valve operation mode change mechanism 58. It is possible to switch between a state in which the valves 46 and the exhaust valves 47 are opened / closed and a state in which the intake valves 46 and the exhaust valves 47 are closed and stopped.

  The operation of the intake side valve actuation mode change mechanism 57 and the exhaust side valve actuation mode change mechanism 58 corresponding to the cylinders at both ends along the cylinder arrangement direction is controlled by the valve control devices 81, 81. As shown in FIGS. 2 and 3, the valve control devices 81, 81 are located forward and upward from the support shaft 107 that swingably supports the front portion of the swing arm 18 on the pivot plate 16. As arranged, it is attached to the rear surface of the crankcase 26.

  In FIG. 6, the valve control device 81 includes a spool valve 84 attached to the rear surface of the crankcase 26, and an electromagnetic on-off valve 85 as a driving means attached to the spool valve 84.

  The spool valve 84 includes a valve housing 86 that has an inlet port 88 and an outlet port 89 and is fastened to the rear surface of the crankcase 26, and a spool valve body 87 that is slidably fitted to the valve housing 86. .

  The valve housing 86 has a bottomed sliding hole 90 that closes one end and opens the other end, and a cap 91 that closes the other end opening of the sliding hole 90 is fitted into the valve housing 86. Is done. The spool valve body 87 is slidably fitted into the sliding hole 90, and a spring chamber 92 is formed between the spool valve body 87 and one end closed portion of the sliding hole 90, A pilot chamber 93 is formed between the other end of the spool valve body 87 and the cap 91. The spring chamber 92 accommodates a spring 94 that biases the spool valve element 87 toward the side where the volume of the pilot chamber 93 is reduced.

  The inlet port 88 and the outlet port 89 are provided in the valve housing 86 so as to open to the inner surface of the sliding hole 90 at positions spaced sequentially from one end along the axis of the sliding hole 90 toward the other end side. The spool valve body 87 is provided with an annular recess 95 capable of communicating between the inlet port 88 and the outlet port 89. Thus, as shown in FIG. 6, when the spool valve body 87 is moved to a position where the volume of the pilot chamber 93 is minimized, the spool valve body 87 is in a state of blocking between the inlet port 88 and the outlet port 89. is there.

  An oil filter 96 is attached to the inlet port 88, and an orifice hole 97 communicating with the inlet port 88 and the outlet port 89 is formed in the valve housing 86. Therefore, even if the spool valve element 87 is in a position where the inlet port 88 and the outlet port 89 are blocked as shown in FIG. 6, the inlet port 88 and the outlet port 89 are communicated with each other through the orifice hole 97. The hydraulic oil supplied to the port 88 is throttled by the orifice hole 97 and flows to the outlet port 89 side.

  The valve housing 86 is provided with a release port 98 that communicates with the outlet port 89 through the annular recess 95 only when the spool valve body 87 is in a position where the inlet port 88 and the outlet port 89 are blocked. The port 98 opens into the crankcase 26.

  The valve housing 86 is provided with a passage 99 that always communicates with the inlet port 88, and this passage 99 is connected to the connection hole 100 formed in the valve housing 86 through the pilot chamber 93 via the electromagnetic opening / closing valve 85. Connected. Accordingly, when the electromagnetic on-off valve 85 is opened, the hydraulic pressure is supplied to the pilot chamber 93, and the spool valve element 87 increases the volume of the pilot chamber 93 by the hydraulic pressure of the hydraulic pressure introduced into the pilot chamber 93. By being driven, the inlet port 88 and the outlet port 89 are communicated with each other via the annular recess 95 of the spool valve body 87 and the outlet port 89 and the release port 87 are blocked.

  Incidentally, as shown in FIG. 4, an oil pump 117 is housed in the crankcase 26, and the rotational power from the input shaft 35 of the transmission M is transferred to the oil by the transmission mechanism 119 using the endless chain 118. It is transmitted to the pump 117. Thus, the oil sucked into the oil pump 117 through the oil strainer 120 is supplied to the inlet port 88 of the spool valve 84 in the valve operating control device 81 through the passage 101 provided in the crankcase 26. . Further, the outlet port 89 of the spool valve 84 is connected to the intake side and exhaust valve operation mode changing mechanisms 57..., 58 via passages 102 provided in the crankcase 26, the cylinder block 27, the cylinder head 28 and the holder 59. Are communicated with the annular recesses 77.

  The passage 101 connecting the oil pump 117 and the valve control device 81 extends from the oil pump 117 to the rear surface side of the crankcase 26 and further extends upward along the rear surface of the crankcase 26. It is done. The passage 102 connecting the valve control device 81 and the intake side and exhaust valve operation mode changing mechanisms 57 and 58 extends upward along the rear surface of the crankcase 26, and then forwards along the upper surface of the crankcase 26. And then extending upward along the rear surfaces of the cylinder block 27 and the cylinder head 28, and further extending in the holder 59 toward the intake side and exhaust valve operation mode changing mechanisms 57 and 58, so that the crankcase 26, the cylinder block 27, cylinder head 28 and holder 59.

  When the electromagnetic opening / closing valve 85 of the valve control device 81 is opened, the inlet port 88 and the outlet port 89 communicate with each other so that the hydraulic chambers 62 of the intake side and exhaust side valve operation mode changing mechanisms 57, 58,. The high-pressure hydraulic pressure acts, and the intake side and exhaust valve operation mode changing mechanisms 57... 58 are operated so as to close the intake valves 46 and exhaust valves 47. In a state where the valve 85 is closed, the inlet port 88 and the outlet port 89 are blocked and the outlet port 89 communicates with the release port 87, whereby the hydraulic pressure in the hydraulic chamber 62 is released, and the intake side and exhaust side valves are released. The slide pins 46 of the operation mode changing mechanisms 57... 58 move to positions where the intake valves 46 and exhaust valves 47 are opened and closed.

  The valve control devices 81 and 81 are attached to the rear surface of the crankcase 26 so that the longitudinal directions of the electromagnetic on-off valves 85 included in the valve control devices 81 are aligned with the rear surface of the crankcase 26. 3 in a plan view, arranged between a pair of left and right pivot plates 16 as shown in FIG. 3, and in a side view it overlaps with the pivot plates 16 as shown in FIGS. 1 and 2 and is connected to the chain 110 of the chain transmission means 22. It is arranged at the overlapping position.

  In addition, as shown in FIG. 3, the pair of valve control devices 81 and 81 are arranged symmetrically with respect to the vehicle body center line CB that extends forward and backward through the center of the vehicle body frame F in the width direction.

  Further, the rear cushion unit 20 provided between a member constituting a part of the link mechanism 19 and the upper portion of the pivot plate 16 passes through the through hole 121 provided in the front portion of the swing arm 18 so as to penetrate the center of the vehicle body. Although arranged behind the crankcase 26 on the line CB, the pair of valve control devices 81, 81 provide a gap larger than the width W of the rear cushion unit 20 in the vehicle width direction. Thus, it arrange | positions symmetrically with respect to the said vehicle body centerline CB. According to the arrangement of the double valve control devices 81, 81, when performing maintenance work of the valve control devices 81... From the rear of the engine E, the rear cushion unit 20 does not get in the way and the workability is improved. Can be increased.

  Next, the operation of this embodiment will be described. Since the valve operating control devices 81 and 81 for controlling the operation of the valve operating device 50 are attached to the rear surface of the crankcase 26, the engine E is small in the direction along the cylinder axis C. Therefore, it is possible to increase the degree of freedom in the arrangement of the components arranged at the upper end portion of the engine body 25. Further, it is possible to effectively prevent the crankcase 26 from hitting a stepping stone or muddy water from the front and the like on the valve control devices 81.

  Further, the valve control devices 81 are attached to the rear surface of the crankcase 26 in front of the support shaft 107 that swingably supports the front portion of the swing arm 18 on the pivot plate 16. The valve control devices 81 can be arranged by effectively using the dead space between the cases 26. Moreover, since the valve control devices 81 are arranged above the support shaft 107, the front of the swing arm effectively suppresses stepping stones, muddy water, etc. from below from hitting the valve control device. Can do.

  Further, since the valve control devices 81 are disposed between the pair of pivot plates 16 in a plan view, the dead space generated between the pivot shafts 16 and the crankcase 26 and between the pivot plates 16 is made effective. It is possible to arrange the valve control devices 81.

  Further, since the valve control devices 81 are arranged at positions overlapping the pivot plates 16 in a side view, the pivot plates 16 can effectively prevent the stepping stones from the side from hitting the valve control devices 81. Can be deterred.

  Further, since the pair of valve control devices 81 are arranged symmetrically with respect to the vehicle body center line CB that extends forward and backward through the center in the width direction of the vehicle body frame F, the weight of the power unit P is relative to the vehicle body center line CB. Can be prevented from being biased to the left or right.

  Furthermore, since the longitudinal direction of the electromagnetic on-off valves 85 included in the valve control devices 81 is arranged along the rear surface of the crankcase 26, the valve control devices 81 project backward from the rear surface of the crankcase 26. It is possible to prevent the engine E from increasing in length. Further, the front-rear length of the motorcycle can be shortened by bringing the components behind the engine E closer to the rear side of the crankcase 26.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the above embodiment, in order to place the cylinders at both ends along the cylinder arrangement direction into the cylinder deactivation state, the pair of valve control devices 81 and 81 individually corresponding to the cylinders that can be in the cylinder deactivation state are used. The present invention can be applied even to a power unit in which a single valve control device 81 is used for two cylinders that can be in a cylinder deactivation state.

  Also, not a cylinder deactivation, but a valve operating device that changes the opening / closing operation characteristics of the intake and exhaust valves that are always open / closed, and a movement that changes the opening / closing operation characteristics of the intake / exhaust valves that always operate. The present invention can also be applied to an apparatus in which the operation of the valve device is controlled by a valve operating control device.

1 is a left side view of a motorcycle. It is the partially cutaway side view which looked at the power unit from the left side. FIG. 3 is a plan view of a part of a vehicle body frame and a power unit as seen from the direction of arrow 3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is a longitudinal cross-sectional view of an intake side valve operation mode changing mechanism. FIG. 6 is a sectional view taken along line 6-6 of FIG.

Explanation of symbols

16 ... Pivot plate 18 ... Swing arm 22 ... Chain transmission means 25 as power transmission means ... Engine body 26 ... Crank case 30 ... Crank shaft 46 ... Engine valve Intake valve 47 ... Exhaust valve 50 as engine valve ... Valve control device 81 ... Valve control device 85 ... Electronic on-off valve 107 as drive means ... Support shaft CB ... Center of vehicle body Line E ... Engine F ... Body frame M ... Transmission P ... Power unit

Claims (7)

  An engine (E) having a valve operating device (50) capable of changing the operation mode of the engine valve (46, 47) and a valve operating control device (81) for controlling the operation of the valve operating device (50). In the motorcycle power unit in which the engine body (25) is mounted on the vehicle body frame (F) and the transmission (M) is housed in the crankcase (26) of the engine body (25), the valve control device (81 Is mounted on the rear surface of the crankcase (26).   A swing arm (18) that pivotally supports a rear wheel (WR) is supported on a pair of left and right pivot plates (16) included in the vehicle body frame (F) via a support shaft (107) so as to be swingable. The power unit for a motorcycle according to claim 1, wherein the valve operating control device (81) is arranged in front of the shaft (107).   The power unit for a motorcycle according to claim 2, wherein the valve operating control device (81) is disposed above the support shaft (107).   The motorcycle power unit according to claim 2 or 3, wherein the valve control device (81) is disposed between the pair of pivot plates (16) in a plan view.   The motorcycle power unit according to claim 4, wherein the valve control device (81) is disposed at a position overlapping the pivot plate (16) in a side view.   The plurality of valve control devices (81) are arranged symmetrically with respect to a vehicle body center line (CB) extending forward and backward through the center in the width direction of the vehicle body frame (F). The motorcycle power unit described.   The valve control device (81) is arranged on the rear surface of the crankcase (26) so that the longitudinal direction of the drive means (85) included in the valve control device (81) is aligned with the rear surface of the crankcase (26). The motorcycle power unit according to claim 1, wherein the motorcycle power unit is attached to the motorcycle.

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