Patent Publication Number: US-6698393-B2

Title: Crankshaft phase adjustment structure

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2001-252168 filed on Aug. 22, 2001 the entire contents thereof is hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to crankshaft phase adjustment structure and more particularly relates to the arrangement structure of a window for performing work for phase adjustment. 
     2. Description of Background Art 
     In Japanese published examined utility model application No. Hei 1-14745, an engine is disclosed in which an ACG for power generation is provided to one end of a crankshaft and a plurality of windows for performing work via which the end of the crankshaft and the outside periphery of the ACG can be viewed are provided to a case cover covering the side of the ACG. 
     In the case where a phase is adjusted in the structure, first a cap for the window for performing work is removed, the crankshaft is rotated from the outside by turning a bolt that tightens an ACG on the crankshaft via the window for performing work is located on an extended line of the crankshaft, a top dead center of a piston is adjusted, checking the position of an alignment mark provided to a flywheel of ACG from another window for performing work and a phase of the engine is adjusted. 
     As the structure becomes more complex when a plurality of windows for performing work are provided as described above, it is desired that a structure should be provided wherein a window for performing work can be simplified. As a window for performing work cannot be provided to a case cover on the side of the ACG when an engine is configured so that oil is supplied from the side of the ACG to an oil passage of a crankshaft, the arrangement structure of a window for performing work that is suitable for such a lubrication structure is also desired. The object of the invention is to realize such requests. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     To solve the above problem, the present invention is directed to a crankshaft phase adjustment structure that is based upon an engine in which a primary drive gear is provided to the side of one end of a crankshaft and an ACG is provided to the side of the other end and which is configured so that oil is supplied to an oil passage provided to the axis of the crankshaft wherein the oil passage of the crankshaft is open to the end of the crankshaft on the side of the ACG. A window is provided for performing work for adjusting a phase that is formed in a position in the vicinity of an extended line of the axis of the crankshaft of a case cover on the side of the primary drive gear and an alignment mark is provided to the crankshaft that can be viewed from the window for performing work or a part rotated integrally with the crankshaft and the edge of the window for performing work. 
     The present invention includes a center of the window for performing work that is set off from the axis of the crankshaft. 
     According to the present invention, as the window for performing work in the vicinity of the extended line of the crankshaft is provided to the case cover on the side of the clutch and the window for performing work on the case cover on the side of ACG is done away with, a lubrication structure in which oil is supplied from the side of ACG to the crankshaft is enabled. 
     As the window for performing work is provided to the position in which the crankshaft or the part rotated integrally with the crankshaft can be viewed on the case cover on the side of the clutch and the alignment mark is provided to the edge of the window for performing work and the crankshaft or the part rotated integrally with the crankshaft, the rotation of the crankshaft can be adjusted, checking the alignment mark from the same window for performing work. Therefore, the adjustment of a phase of the crankshaft is facilitated, as the window for performing work can be simplified, the structure of the window for performing work can be simplified and in addition, the lightening and the reduction of the cost are enabled. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is a left side view showing a water-cooled four-cycle engine to which this embodiment is applied; 
     FIG. 2 is a sectional view showing a main part of the engine; 
     FIG. 3 is a sectional view showing a balancer mechanism; 
     FIG. 4 is an enlarged sectional view showing a window for performing work; and 
     FIG. 5 is a side view showing the side of the outside surface of a case R cover. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, in this engine, a cylinder block  2  is provided over a crankcase  1 . A cylinder head  3  and a cylinder head cover  4  are provided on/over the cylinder block. A piston  5  is slid in the cylinder block  2  so that it can be reciprocated for rotating the crankshaft  7  (the reference number indicates the center) via a connecting rod  6 . The crankshaft  7  is housed in the crankcase  1  and is engaged with a primary driven gear  11  integrated with a clutch  10  via a primary drive gear  9  provided on the crankshaft  7 . 
     The main shaft  12  and the countershaft  13  (the reference numbers indicate the respective center) respectively forming a transmission mechanism are arranged in parallel with the crankshaft  7  with plural transmission gears  14  and  15  provided on the respective shafts that are always engaged. The plural transmission gears  14  and  15  are housed in a transmission case in the crankcase  1 . The main shaft  12  is connected to the clutch  10  for intermittently operating the clutch  10  by a clutch lever  17 . The combination of the transmission gears  14  and  15  is selected by a well-known gear selecting mechanism and a shift is output to an output sprocket  18  provided to one end of the countershaft  13 . 
     As shown in FIG. 2, the crankcase  1  is divided into right and left parts. The crankcase is composed of a case L  20  on the left side and a case R  21  on the right side, and a case L cover  22  and a case R cover  23  are attached to the respective outsides. 
     The crankshaft  7 , the main shaft  12  and the countershaft  13  are respectively supported by a bearing between the case L  20  and the case R  21 , and the crankshaft  7  is housed in the crankcase  8  formed in a sealed state between the case L  20  and the case R  21 . The transmission mechanism including the main shaft  12 , the countershaft  13  and the transmission gears  14  and  15  is housed in a transmission case  16  formed between the case L  20  and the case R  21  next to the crankcase  8 . The crankcase  8  is partitioned by the transmission case  16  and a partition to be sealed. A clutch housing  25  is formed among the case R  21 , the case R cover  23  and a clutch cover  24 , and a wet clutch is housed here. 
     The main shaft  12  that is connected to the clutch  10  is a hollow shaft. A push rod  26  pierces the main shaft and the clutch is intermittently operated by pushing one end of the push rod by a cam  27  formed at one end of the clutch lever  17 . ACG  28  is provided to one end of the crankshaft  7 . 
     As shown in FIG. 3, a balancer drive gear  30  is provided in the vicinity of the primary drive gear  9  on the crankshaft  7 , and a balancer driven gear  31  engaged with the balancer drive gear is provided at one end of a balancer shaft  32 . The balancer shaft  32  is arranged in parallel with the crankshaft  7 , is supported between the case L  20  and the case R  21  and balancer weights  33  and  34  are provided at both ends. One balancer weight  33  is provided separately from the balancer driven gear  31  with one balancer weight axially overlapped with the balancer driven gear, and the other balancer weight  34  is integrated with the other end of the balancer shaft  32 . 
     An axial fitting hole  32   a  is provided to the end to which the balancer weight  33  is provided of the balancer shaft  32 , the end with an anomalous outline  36   a  formed on a driving shaft  36  of a water pump  35  is fitted into the axial fitting hole and is coupled to the axial fitting hole so that they can be coaxially rotated integrally and drives the water pump  35  together with the balancer shaft  32 . 
     A separate gear  37  is provided to a boss of the other balancer weight  34  so that the gear can be integrally rotated. The gear  37  is engaged with an oil pump gear  38 , the oil pump gear  38  rotates an integrated driving shaft  39  and drives an oil pump  40 . The driving shaft  39  is supported by the case L  20  in parallel with the balancer shaft  32 . The oil pump  40  is formed on the side of the case L  20  and is in part combined with the case R  21 . 
     For the supply of oil to the oil pump  40 , oil is sent from an oil reservoir  41  formed at the bottom of the case R  21  of the crankcase  8  to an oil pan via a lead valve not shown by the rotation of a crank web  42 . Oil sent from the oil pump  40  in a state in which pressure is applied is supplied from a discharge passage  43  to required locations such as an oil passage  46  provided to the core of the crankshaft  7  via an oil filter  44  provided on the inner side of the case L cover  22  and an oil passage  45  formed inside the case L cover  22 . 
     As shown in FIGS. 2 to  4 , the primary drive gear  9  and the balancer drive gear  30  are fixed at the end on the right side of the crankshaft  7  on the reverse side to the side on which ACG  28  is provided by a bolt  48 . A window for performing work  49  is open to the case R cover  23  in the vicinity of the bolt  48  and is covered with a cap  50  screwed thereon. 
     As shown in FIG. 4, the axis of the bolt  48 , that is, the axis C 1  of the crankshaft  7  and the center line C 2  of the window for performing work  49  and the cap  50  are off by a dimension d. The bolt  48  has a hexagon head  51  and in the center, a hexagonal concave portion  52  is formed. A hexagonal concave portion  53  is also provided to the cap  50 . 
     The window for performing work  49  is located in a position and has a size in which an alignment mark  54  is provided to the whole head  51  and the outside peripheral side in the vicinity of the teeth of the primary drive gear  9  can be viewed as shown in FIG. 5, and is located in a position which does not interfere with the clutch cover  24 . An alignment mark  55  is matched with the alignment mark  54  and is provided to the edge of the window for performing work  49 . The alignment marks  54  and  55  shown in FIG. 4 are exaggeratingly drawn to definitely show the positions and are different from actual ones. 
     As is clear from FIG. 5, the alignment mark  55  is formed in the form of a triangle for example at the edge of the window for performing work  49  according to a suitable method such as a marking. In the meantime, the alignment mark  54  is formed in the form of a circle for example according to a suitable method such as marking and both marks are arranged so that they are close when they are matched. The alignment mark  54  of the primary drive gear  9  is set so that a crank is located in a position at a time when a piston is located in a top dead center when the alignment mark  54  is matched with the alignment mark  55 . The crankshaft  7  and the primary drive gear  9  are connected via a spline and the primary drive gear  9  is necessarily built in the crankshaft  7  in phase with the combination of phases at this time. 
     Next, the action of this embodiment will be described. As shown in FIGS. 2 and 3, as the window for performing work  49  is provided to the case R cover  23  on the side of the clutch in a position in the vicinity of an extended line of the crankshaft  7  and no window for performing work is provided to the case L cover  22  on the side of ACG  28 , a lubrication structure in which oil is supplied from the oil passage  45  provided to the case L cover  22  to the oil passage  46  of the crankshaft  7  via the side of ACG is enabled. Therefore, the oil passage  45  can be made relatively short and simple. 
     As shown in FIGS. 4 and 5, as the window for performing work  49  is provided to the case R cover  23  on the side of the clutch and the bolt  48  located at the end of the crankshaft  7  and the alignment mark  54  of the primary drive gear  9  can be simultaneously viewed, the rotation of the crankshaft  7  can be adjusted by the bolt  48 , checking the alignment mark  54  from the same window for performing work  49  and a top dead center of the crankshaft  7  can be adjusted by matching the alignment mark  54  on the side of the primary drive gear  9  with the alignment mark  55  of the case R cover  23 . Therefore, the adjustment of the phase of the crankshaft  7  is facilitated, as one window for performing work  49  has only to be provided, the structure of the window for performing work  49  can be simplified and in addition, one cap  50  has only to be provided. 
     At this time, as the hexagonal concave portion  52  is provided to the head  51  in a hexagonal convex shape of the bolt  48 , the convex shape having a large diameter formed on the side of the outside periphery of the head  51  is used when the head is tightened with a large torque. When the crankshaft  7  is rotated with a small torque for adjustment, a tool having a smaller diameter than the convex shape via the window for performing work  49  from the outside is fitted to the hexagonal concave portion  52  and the crankshaft  7  can be rotated. 
     In addition, the bolt  48  and the alignment mark  54  can be simultaneously viewed by setting the center C 2  of the window for performing work  49  off the axis C 1  of the crankshaft  7  and the area of an opening can be reduced. In addition, the window for performing work can be arranged in a position in which interference with the clutch  10  can be avoided. Therefore, the reduction of the number of parts, the lightening and the arrangement of the window for performing work  49  compatible with the adjacent clutch  10  can be realized. 
     The invention is not limited to the above-mentioned embodiment and various transformations and applications are allowed in the same principle of the invention. For example, the alignment mark  54  may be also provided to the crankshaft itself or a member rotated integrally with the crankshaft except the primary drive gear  9 . 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.