JP2005090691A - Engine balancer unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to support firmly one of balancer shaft of one pair of balancer shafts to the revolution free near a driven sprocket. <P>SOLUTION: A balancer unit of this engine has a shaft extension 26 that the first balancer shaft 11 extends in front and is composed so that the driven sprocket 16 is attached to the shaft extension part 26. A case member 13 has the first bearing unit 31 (32, 33) that bears the balancer shaft 11 near a weight part 21, 22 and an engaging gear 23 and the second bearing unit 34 that makes a ball bearing near the driven sprocket 16. The case member 13 includes an upper case 13U to couple with a cylinder block 4 and a lower case 13L to contact with the upper case 13U and equips a case extension part 41 with the upper case 13U that extends in front. The first bearing unit 31 (32, 33) is composed of the hole made by contacting halves part each other that is equipped to both cases 13U, 13L and the second bearing unit part 34 is composed of the hole made integrally with the case extension part 41. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine balancer device and belongs to the technical field of engine vibration and noise countermeasures.

  In general, a balancer device provided to suppress the generation of vibration and noise in an engine for automobiles or the like is a pair of balancer shafts each having a weight portion arranged in parallel to a crankshaft and rotatably supported by a case member. The case member is attached to the lower part of an engine block (for example, a group of members constituting the engine body such as a cylinder block, a lower block, a bearing cap, a bearing frame, etc.) that rotatably supports the crankshaft. It is the structure which was made. A drive sprocket provided at one end of the crankshaft (for example, the front end of the engine body) and one end of one balancer shaft (first balancer shaft) of the pair of balancer shafts. An endless chain is wound around the driven sprocket, and the interlocking gears provided on both balancer shafts are engaged with each other. The rotation of the crankshaft causes the pair of balancer shafts to interlock and rotate in opposite directions. The vertical vibration generated by the swing of the weight due to the rotation of the balancer shaft cancels the vertical vibration generated by the explosion in each cylinder of the engine, reducing engine vibration and accompanying noise. Is done.

  In this case, according to Patent Document 1, a pair of front and rear weight portions are provided on the balancer shaft in the axial direction, and an interlocking gear is provided in front of the front weight portion and formed between the weight portions. The balancer shaft is rotatably supported by the case member by the rear journal portion and the front journal portion formed immediately before the interlocking gear being respectively supported by the front and rear bearing portions provided on the case member. Has been.

  In particular, according to the above-mentioned Patent Document 1, the case member is composed of an upper case and a lower case that are in contact with each other, and the rear bearing portion has a halved portion provided in each case in a pair of both cases. It is a bearing part formed in a hole shape by making contact with each other, and the front bearing part is a bearing part formed in a hole shape by a hole provided integrally with one case from the beginning. .

  Therefore, in order to accommodate the balancer shaft in the case member, before the upper case and the lower case are brought into contact with each other, one end portion of the balancer shaft is inserted into the hole of the front bearing portion, and the front journal portion is supported by the front bearing portion. After that, the rear journal part is placed on the half part of the rear bearing part. Then, by bringing the upper case and the lower case into contact with each other, the rear bearing portion is formed into a hole shape, and the rear journal portion is supported by the rear bearing portion.

JP 2001-74104 A (FIGS. 2 and 3)

  By the way, in order to ensure the effect of reducing the noise and vibration of the engine by the balancer device, the weight portion of the balancer shaft is an intermediate portion in the axial direction of the engine (for example, in the case of an in-line four-cylinder engine, the second and third cylinders). (Corresponding position). On the other hand, the driven sprocket of the first balancer shaft is arranged side by side with the driving sprocket of the crankshaft so that the endless chain can be wound properly and reliably. It arrange | positions at the one end part (For example, the edge part of the front side of an engine main body) of a direction. Therefore, the first balancer shaft to which the driven sprocket is attached is extended longer on the one end side than the second balancer shaft to which the driven sprocket is not attached, and the driven sprocket is attached to the shaft extension portion. Since the tension of the endless chain acts on the driven sprocket, if the first balancer shaft is not rotatably supported in the vicinity of the driven sprocket, the first balancer shaft is bent by the shaft extension portion and the driven sprocket is Vibration and noise due to the balancer device may occur.

  The present invention addresses the above-described problems in the balancer device of an engine having a configuration in which a driven sprocket is attached to one balancer shaft of a pair of balancer shafts, and the one balancer shaft is connected to the driven sprocket. It is an object to firmly and rotatably support in the vicinity. Hereinafter, the present invention will be described in detail including other problems.

  In other words, the invention according to claim 1 of the present application is provided with first and second balancer shafts each having a weight portion and rotating together, and the balancer shaft attached to the lower part of the engine block supporting the crankshaft. A winding member is wound around a driving side rotating body attached to one end of the crankshaft and a driven side rotating body attached to one end of the first balancer shaft. The balancer shaft of the engine having the above-described structure, wherein the balancer shaft has interlocking gears meshing with each other on the one end side with respect to the weight portion, and the first balancer shaft is on the one end side with respect to the second balancer shaft. A shaft extension portion extending long on the portion side, and the driven-side rotating body is attached to the shaft extension portion, and the case member includes the balancer shaft and the weight portion. And a first bearing portion bearing near the interlocking gear, and a second bearing portion bearing the first balancer shaft near the driven-side rotating body, and the case member includes the engine An upper case coupled to the block and a lower case that is in contact with the upper case, and a case extension extending long on the one end side is provided in any of these cases, and the first bearing portion is It is composed of a hole formed by contact of halved parts provided in both cases, and the second bearing part is composed of a hole provided integrally with the case extension. To do.

  Next, the invention described in claim 2 is characterized in that, in the invention described in claim 1, the case extension portion and the second bearing portion are provided in the upper case.

  Next, the invention according to claim 3 is the invention according to claim 1 or 2, wherein the interlocking gear is constituted by a helical gear, and the case extension portion and the second bearing portion of the upper case and the lower case are provided. Only the case that is not provided is provided with a convex portion that receives the thrust force acting on the balancer shaft by the rotation of the helical gear.

  Next, the invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the case member has a sealed structure that does not expose the weight portion of the balancer shaft, and the case member A lubricating oil passage for supplying lubricating oil to the first and second bearing portions provided in the case member is formed inside a wall portion constituting the case member.

  First, according to the first aspect of the present invention, the first balancer shaft to which the driven-side rotator is attached is arranged near the driven-side rotator by the second bearing portion provided in the case extension of the case member. Since the first balancer shaft is bent at the shaft extension, the driven-side rotating body vibrates and the vibration and noise caused by the balancer device are avoided. Is done.

  In addition, since the second bearing portion is configured by a hole integrally provided in the case extension portion from the beginning, the support rigidity of the second bearing portion is increased, and the shaft extension portion of the first balancer shaft is more firmly supported. Thus, problems such as bending of the first balancer shaft and vibration of the driven-side rotating body can be avoided reliably. On the other hand, if the second bearing part is a halved structure provided in the upper case and the lower case like the first bearing part, the contact between the two cases is shifted due to the tension of the endless chain, and the support rigidity is reduced. However, there is a possibility that problems such as the bending of the first balancer shaft and the vibration of the driven-side rotating body cannot be satisfactorily suppressed.

  On the other hand, since the first bearing portion has a halved structure provided in the upper case and the lower case, the insertion distance of the balancer shaft to the second bearing portion when the balancer shaft is accommodated in the case member is shortened. The member can be made compact. On the other hand, when the first bearing portion is a hole structure integrally provided from the beginning like the second bearing portion, the insertion distance for moving the one end portion of the balancer shaft to the position of the second bearing portion is increased. Accordingly, it becomes necessary to lengthen the case member in the axial direction, and the compactness of the case member is hindered.

  In particular, there is a large-diameter interlocking gear on the balancer shaft closer to the one end than the weight portion. Therefore, when the balancer shaft is inserted, a space (gear that does not hinder the axial movement of the interlocking gear). A non-interference space is required for the case member. Therefore, as the insertion distance of the balancer shaft becomes longer, the gear non-interference space that is unnecessary and wasted after assembling occupies a large space in the lower part of the engine block, thereby reducing the layout.

  Next, according to the second aspect of the present invention, the case extension and the second bearing portion are provided on the upper case, which is directly coupled to the engine block, of the upper case and the lower case. The support rigidity of the bearing portion is further increased, and the support of the shaft extension portion of the first balancer shaft is further stabilized.

  Next, according to the third aspect of the invention, the thrust regulating structure of the balancer shaft resulting from the rotation of the helical gear constituting the interlocking gear is simplified, and the case member can be reduced in weight.

  Next, according to the invention described in claim 4, since the case member has a sealed structure that does not expose the weight portion of the balancer shaft, for example, the weight portion stirs the oil in the oil pan when the balancer shaft rotates. As a result, there is no fear that bubbles are sucked into the oil passage from the oil strainer and cause problems of cavitation (intake of air) in the oil passage. It is also possible to prevent unnecessary oil from entering the case member from the outside. In addition, the lubrication of the first bearing portion for bearing the balancer shaft in the vicinity of the weight portion and the interlocking gear and the lubrication of the second bearing portion for bearing the first balancer shaft in the vicinity of the driven-side rotating body are stably and reliably performed. Done. Hereinafter, the present invention will be described in more detail through the best mode for carrying out the invention.

  In the present embodiment, the present invention is applied to the engine 1 shown in FIG. The engine 1 is an inline 4-cylinder reciprocating engine. FIG. 1 shows the main body of the engine 1 as viewed from the front side (the side with the chain cover) (however, the chain cover is removed). The engine block 2 constituting the main body of the engine 1 includes a cylinder block 4 to which a cylinder head 3 is attached at an upper portion, and a bearing frame 5 attached to the lower portion of the cylinder block 4. The bearing frame 5 is formed by connecting a plurality of bearing caps and integrating them into a single member. The bearing frame 5 cooperates with the cylinder block 4 and rotatably supports the crankshaft 6. In that case, the cylinder block 4 supports the upper half of the crankshaft 6, and the bearing frame 5 supports the lower half of the crankshaft 6. An oil pan 7 for storing oil is attached to the lowermost surface of the cylinder block 4.

  The balancer device 10 of the engine 1 includes a case member 13 that rotatably supports a pair of left and right balancer shafts 11 and 12. The case member 13 is attached to the lower part of the cylinder block 4 in the same manner as the bearing frame 5 and the oil pan 7. In particular, the case member 13 is attached to the lowermost surface of the cylinder block 4 as with the oil pan 7.

  Next, FIG. 2 is a partially enlarged view of the state in which the bearing frame 5 and the case member 13 of the balancer device 10 are respectively attached to the lower portion of the cylinder block 4 (however, the crankshaft 6 and later will be described). The sprockets 15, 16, 19, the endless chain 17, the support bracket 51, the oil pump 18, etc. are removed). As shown in FIG. 2, the case member 13 includes an upper case 13U that is directly coupled and fixed to the cylinder block 4 and a lower case 13L that contacts the upper case 13U from below. Both cases 13U and 13L are made of an aluminum alloy, and are connected by a plurality of bolts 13B... 13B. The case member 13 is disposed in the oil pan 7 while straddling the bearing frame 5.

  The bearing frame 5 is fastened to the lower portion of the cylinder block 4 by a plurality of bolts 8... The case member 13 is fastened to the lowermost surface of the cylinder block 4 by a plurality of bolts 14...

  Returning to FIG. 1, a drive sprocket 15 is attached to the front end portion (front end portion of the engine body) of the crankshaft 6, and the front end portion of the first balancer shaft 11 of the pair of left and right balancer shafts 11 and 12 is attached. A driven sprocket 16 is attached, and an endless chain 17 is wound between the sprockets 15 and 16. An oil pump 18 is disposed on the front side of the cylinder block 4, and the endless chain 17 is also wound around a driven sprocket 19 attached to the drive shaft of the oil pump 18.

  Next, FIG. 3 is a bottom view of the upper case 13U constituting the upper half of the case member 13 (that is, a mating view with the lower case 13L), and FIG. 4 is a lower half of the case member 13. FIG. 5 is a top view of the lower case 13L (ie, a mating surface view with the upper case 13U), and FIG. 5 is similar to FIG. 3 showing the initial stage of the work of accommodating the pair of left and right balancer shafts 11 and 12 in the upper case 13U. FIG. 6 is a bottom view similar to FIG. 5 showing the final stage of the operation of housing the pair of left and right balancer shafts 11 and 12 in the upper case 13U, and FIG. 7 shows the balancer shaft 11 and FIG. 8 is a bottom view similar to FIG. 6 of the case member 13 in a state where the lower case 13L is brought into contact with the upper case 13U in which the housing 12 is accommodated and coupled with bolts 13B... 13B. Along FIG. 9 is a fragmentary longitudinal sectional view (however, the crankshaft 6, sprockets 15, 16, 19, endless chain 17, support bracket 51, etc. are attached) and FIG. The state in which the tip of the case extension 41 of the case member 13 is supported on the support bracket 51 attached to the front side surface of the frame 5 is shown.

  As shown in FIG. 6, the first and second balancer shafts 11, 12 are arranged so as to extend in parallel with the crankshaft 6, respectively, and include a pair of front and rear weight portions 21, 22 and a front weight portion 21. And an interlocking gear 23 for transmission of rotation arranged on the front end side, and interlockingly rotates in the reverse directions R and R at a constant speed by the meshing of the interlocking gears 23. The balancer shafts 11, 12 have a rear journal part 24 between a pair of front and rear weight parts 21, 22, and a front journal part 25 just before the interlocking gear 23. As shown in FIG. 8, the weight portions 21 and 22 are formed in a sector shape that bulges radially from the axis of the balancer shafts 11 and 12 and does not exceed 180 °.

  The first balancer shaft 11 has a shaft extension 26 extending longer on the front end side than the second balancer shaft 12, and a driven sprocket 16 is attached to the shaft extension 26 as shown in FIG. More specifically, as shown in FIG. 8, the tip of the shaft extension 26 of the first balancer shaft 11 is the front end surface of the engine block 2 (or the front ends of the cylinder block 4 and the bearing frame 5 constituting the engine block 2). The front sprocket 16 is attached. The front end portion of the crankshaft 6 also projects forward from the front end surface of the engine block 2 (or the front end surfaces of the cylinder block 4 and the bearing frame 5 constituting the engine block 2), and a drive sprocket 15 is attached to the front end portion. ing.

  As shown in FIG. 8, the driven sprocket 16 of the first balancer shaft 11 and the drive sprocket 15 of the crankshaft 6, and the driven sprocket 19 of the oil pump 18 are mutually in the axial direction of the crankshaft 6 and the balancer shafts 11 and 12. Aligned side by side, the endless chain 17 is wound well and securely. Further, the weight portions 21 and 22 of the balancer shafts 11 and 12 are arranged in an intermediate portion in the axial direction of the engine 1 (positions corresponding to the second cylinder and the third cylinder in the present embodiment), and the balancer device 10 uses the balance of the engine 1. The vibration noise reduction effect is confirmed.

  As shown in FIG. 8, the case member 13 has a first bearing portion 31 for bearing the balancer shafts 11 and 12 in the vicinity of the weight portions 21 and 22 and the interlocking gear 23. The first bearing portion 31 includes a front bearing portion 32 that bears the front journal portions 25 and 25 and a rear bearing portion 33 that bears the rear journal portions 24 and 24.

  As shown in FIG. 8, the case member 13 has a case extension 41 that extends long on the front end side in the same manner as the first balancer shaft 11, and the case extension 41 (more specifically, the case extension 41). The second balancer bearing the first balancer shaft 11 in the vicinity of the driven sprocket 16 attached to the shaft extension 26 (ie, at the shaft extension journal 150 (see FIGS. 5 and 9)). A bearing portion 34 is provided.

  Here, as shown in FIGS. 2 and 3, the case extension 41 and the second bearing 34 are provided on the upper case 13U of the upper case 13U and the lower case 13L.

  As shown in FIGS. 3 and 4, the first bearing portion 31 (32, 33) includes halved portions (semicircular recesses) 32 U, 33 U provided in both the upper case 13 U and the lower case 13 L: As shown in FIG. 2, the second bearing portion 34 is composed of a hole provided integrally with the case extension 41 of the upper case 13U from the beginning. ing.

  As shown in FIG. 8, the case member 13 has a sealed structure that does not expose the weight portions 21 and 22 of the balancer shafts 11 and 12 to the outside. Accordingly, the weights 21 and 22 are agitated to foam the oil in the oil pan 7 during rotation, and the bubbles are sucked in by an oil strainer (not shown), and there is no fear of causing cavitation.

  Further, as shown in FIG. 6, the rear end portions 11 a and 12 a of the balancer shafts 11 and 12 are expanded in diameter, and the rear end surface of the case member 13 is closed without a gap, so that unnecessary oil in the oil pan 7 is removed. Mixing in the case member 13 is suppressed.

  As shown in FIG. 1, a support bracket 51 is attached to a side surface (front end surface of the engine block 2) on one end side of the engine block 2. More specifically, as shown in FIG. 8, the support bracket 51 is attached to the front end surface of the bearing frame 5. As shown in FIG. 1, the support bracket 51 is fastened to the bearing frame 5 by three bolts 52, 53, and 54. As shown in FIG. 2, three seats (floating seats) 62, 63, 64 to which the three bolts 52, 53, 54 are screwed are provided on the front end surface of the bearing frame 5.

  As shown in FIG. 9, the support bracket 51 is provided with a penetrating member (collar member) 71 that penetrates the bracket 51 so as to be relatively movable in the axial direction A of the crankshaft 6 and the balancer shafts 11 and 12. The case extension 41 is supported by the support bracket 51 by fastening the tip of the case extension 41 with the bolt 72 to the penetrating member 71. That is, as shown in FIGS. 2 and 9, a screw hole 72 a into which the bolt 72 is screwed is provided at the tip of the case extension 41.

  As shown in FIG. 1, the support bracket 51 has guide portions 75 and 76 of the endless chain 17. That is, the support bracket 51 also serves as a chain guide. The endless chain 17 is wound around the drive sprocket 15 of the crankshaft 6, the driven sprocket 16 of the balancer shaft 11, and the driven sprocket 19 of the oil pump 18, and the support bracket 51 includes two of them. There is a tensioner 77 for applying tension to the chain running part between the sprockets 15 and 19, and guide parts 75 and 76 for suppressing the swing of the chain 17 of the chain running part between the other two sprockets 19, 16:16, 15. doing.

  Here, as shown in FIG. 9, the support bracket 51 is made of sheet metal (made of thin sheet metal).

  Further, as shown in FIG. 6, the interlocking gears 23, 23 are constituted by helical gears. As shown in FIGS. 4 and 8, the balancer is rotated by the rotation of the helical gears 23, 23 only in the lower case 13 </ b> L in which the case extension 41 and the second bearing portion 34 are not provided. A convex portion (wall portion or thrust restricting portion) 78 that receives the thrust force acting on the shafts 11 and 12 is provided.

  On the other hand, as shown in FIG. 3, a lubricating oil passage 90 for supplying lubricating oil to the first and second bearing portions 31 and 34 provided in the case member 13 is provided inside the wall portion constituting the case member 13. Is formed. That is, a part of the upper case 13U extends rearward (case rearward extension 91), and an oil introduction port 92 that opens upward is formed at the tip. The oil introduction port 92 communicates with an oil supply port (not shown) that opens at the lower surface of the cylinder block 4 when the upper case 13U is coupled to the lower surface of the cylinder block 4. The oil introduction port 92 communicates with a vertical passage 93 provided in the rear extension 91.

  A lateral passage 94 is provided in the rear extension 91. The horizontal passage 94 extends from the lower end portion of the vertical passage 93 to the vicinity of the rear bearing portion 33. The end portion of the horizontal passage 94 is connected to the vertical passage 95, and the vertical passage 95 extends downward and opens at the mating surface of the upper case 13U with the lower case 13L.

  A horizontal passage 96 that extends horizontally from the middle of the vertical passage 95 in the vertical direction to the vicinity of the front bearing portion 32 is provided. The end portion of the horizontal passage 96 is connected to the vertical passage 97, and the vertical passage 97 extends downward and opens at the mating surface of the upper case 13U with the lower case 13L.

  And from any lower opening part of the vertical passages 95 and 97, it continues to this opening part, and it runs on the mating surface with the lower case 13L in the upper case 13U and the half parts 32U and 33U of the first bearing part 31. Upper concave grooves 98U and 99U are formed. Similarly, as shown in FIG. 4, the lower case 13 </ b> L is also formed with lower grooves 98 </ b> L and 99 </ b> L that run on the mating surface with the upper case 13 </ b> U and the half portions 32 </ b> L and 33 </ b> L of the first bearing portion 31. . In this case, as shown in FIGS. 3 and 4, the concave grooves 98U, 99U: 98L, 99L circulate around the insertion holes of the case coupling bolts 13B ... 13B. Then, when the upper case 13U and the lower case 13L are in contact with each other, the upper and lower concave grooves 98U, 99U: 98L, 99L are in contact with each other, so that the lubricating oil passage for stably and reliably supplying the lubricating oil to the first bearing portion 31 is provided. 90 is completed.

  Further, as shown in FIGS. 3 and 8, an intermediate passage 100 is provided that extends upward from the middle of the half portion 32U of the front concave groove 99U in the upper case 13U. The upper end portion of the intermediate passage 100 communicates with the start end portion of the extended lubrication passage 101 that is horizontally provided in the case extension portion 41. The extended lubrication passage 101 extends forward and is connected to a vertical passage 102 extending vertically at the tip of the case extension 41. As shown in FIG. 8, the longitudinal passage 102 opens in the inner surface of the hole of the second bearing portion 34, and thereby, the lubricating oil passage 90 that supplies the lubricating oil to the second bearing portion 34 stably and reliably. Is completed.

  Next, the operation of the balancer device 10 will be described. During operation of the engine 1, the rotation of the crankshaft 6 is transmitted to the first balancer shaft 11 via the chain 17 and further transmitted to the second balancer shaft 12 via the interlocking gears 23 and 23. As a result, the first balancer shaft 11 and the second balancer shaft 12 rotate in conjunction with the crankshaft 6 in opposite directions R and R (see FIG. 6). The vertical vibration force generated by the swinging of the weight portions 21 and 22 due to the rotation of the balancer shafts 11 and 12 cancels the vertical vibration force generated by the explosion in each cylinder of the engine 1. Vibration and accompanying noise are reduced. In the four-cylinder engine as in the present embodiment, since the secondary vibration force is generally a problem, the balancer shafts 11 and 12 rotate at twice the speed of the crankshaft 6 and the secondary of the engine 1 It is designed to counteract the vibration force.

  Next, an operation of housing the balancer shafts 11 and 12 in the case member 13 in the balancer device 10 will be described. First, as shown in FIG. 5, the rotational phases of the weight portions 21 and 22 of the pair of balancer shafts 11 and 12 are matched to engage the interlocking gears 23 and 23. Next, before the upper case 13U and the lower case 13L are brought into contact with each other in this state, the pair of balancer shafts 11 and 12 are mounted on the halved portions 32U and 33U of the first bearing portion 31 in the upper case 13U. Put.

  At this time, the distal end portion of the shaft extension portion 26 of the first balancer shaft 11 is immediately behind the hole-shaped second bearing portion 34 of the case extension portion 41 of the upper case 13U. The interlocking gears 23 are located at the rearmost part of the gear non-interference space 120 (see FIG. 8) formed in the upper case 13U. On the other hand, the weight parts 21 and 22 bulge toward the anti-upper case 13 side (see FIG. 8). As a result, the balancer shafts 11 and 12 are placed on the halved portions 32U and 33U of the first bearing portion 31 in the upper case 13U without being obstructed by the weight portions 21 and 22, while maintaining a stable level.

  In this state, as shown by an arrow B in FIG. 5, the pair of balancer shafts 11 and 12 are moved horizontally (stroke) forward. As a result, as shown in FIG. 6, the shaft extension journal portion 150 of the first balancer shaft 11 is inserted into the hole of the second bearing portion 34, and the shaft extension portion journal portion 150 is supported by the second bearing portion 34. At the same time, the front journal portions 25 and 25 and the rear journal portions 24 and 24 of the balancer shafts 11 and 12 are respectively placed on the half portions 32U and 33U of the first bearing portion 31 in the upper case 13U.

  Then, in this state, the lower case 13L is brought into contact with the upper case 13U to complete the case member 13, and the first bearing portion 31 is formed in a hole shape so that the first bearing portion 31 (that is, the front bearing portion 32 and the rear bearing portion 32) is formed. The front journal portion 25 and the rear journal portion 24 of the balancer shafts 11 and 12 are supported by the side bearing portion 33).

  At this time, as shown in FIG. 6, the interlocking gears 23, 23 are located at the forefront of the gear non-interference space 120 (see FIG. 8) formed in the upper case 13 </ b> U. Here, the axial position of the weight parts 21, 22 and the axial position of the driven sprocket 16 or the axial position of the tip of the first balancer shaft 11 are determined in advance. If the front bearing portion 32 of the first bearing portion 31 is formed in a hole shape integral with the case member 13, the horizontal stroke distance to the front of the balancer shafts 11 and 12 becomes longer, and accordingly, the position of the interlocking gears 23 and 23, or The position of the front bearing portion 32 moves forward in the axial direction, and as a result, the case member 13 swells forward long.

  On the other hand, in the present embodiment, only the foremost second bearing portion 34 has a hole shape integral with the case member 13, and the other first bearing portions 31 (32, 33) have a half shape. The horizontal stroke distance to the front of the balancer shafts 11 and 12 is shortened. As a result, as shown by the length L in FIG. 6, the gear non-interference space 120 for preventing the horizontal movement of the interlocking gears 23 and 23 is an axis. The case member 13 is made compact by shortening in the direction.

  As shown by an arrow C in FIG. 6, the positioning plate 110 is finally set at the tip of the second balancer shaft 12. However, the positioning plate 110 is removed when the engine 1 is used.

  Next, in the balancer device 10, a configuration in which the tip end portion of the case extension 41 of the case member 13 is supported on the engine block 2 side will be described. As described above, the screw hole 72a is formed at the tip of the case extension 41 (see FIG. 9). The case extension 41 is fixed to the engine block 2 through the screw hole 72a. That is, as described above, the engine block 2 according to the present embodiment includes the cylinder block 4 and the bearing frame 5. The case member 13 of the balancer device 10 is assembled to the lower part of the cylinder block 4. On the other hand, a support bracket 51 for fixing the case extension 41 to the engine block 2 is assembled and fixed to the front end surface of the bearing frame 5 by bolts 52 to 54 in three floating seats 62 to 64. . The case extension 41 is fixed to the engine block 2 side by connecting the tip of the case extension 41 to the support bracket 51 with a bolt 72. That is, the support bracket 51 and the case member 13 or the case extension 41 are assembled via two members, the cylinder block 4 and the bearing frame 5. Therefore, it is difficult for the fastening surface of the support bracket 51 and the fastening surface of the front end portion of the case extension 41 to coincide with each other accurately.

  Therefore, in the present embodiment, the collar member 71 is fitted into the support bracket 51 as shown in FIG. The collar member 71 is movable relative to the support bracket 51 in the axial direction A. The fastening bolt 72 is inserted into the collar member 71 and fastened to the tip of the case member 13. As a result, the case extension 41 and the collar member 71 are integrated, but the case extension 41 is not directly connected to the support bracket 51. Therefore, even if the case extension 41 is displaced with respect to the support bracket 51, the displacement is absorbed by the collar member 71 moving in the axial direction A with respect to the support bracket 51. As shown by the symbol a in FIG. 9, the collar member 71 has a cylindrical portion longer than the thickness of the support bracket 51 made of sheet metal so as to be sufficient for absorbing the displacement.

  As described above, in the present embodiment, the first balancer shaft 11 to which the driven sprocket 16 is attached is rotated in the vicinity of the driven sprocket 16 by the second bearing portion 34 provided in the case extension 41 of the case member 13. Since the first balancer shaft 11 is bent at the shaft extension 26 and the driven sprocket 16 vibrates, the vibration and noise caused by the balancer device 10 are generated instead. Is done.

  In this case, since the second bearing portion 34 is configured by a hole integrally provided in the case extension portion 41 from the beginning, the support rigidity of the second bearing portion 34 is increased, and the shaft extension portion of the first balancer shaft 11 is increased. 26 is more firmly supported, so that problems such as bending of the first balancer shaft 11 and vibration of the driven sprocket 16 are reliably avoided. On the other hand, if the second bearing portion 34 has a half structure provided in the upper case 13U and the lower case 13L like the first bearing portion 31 (32, 33), both cases 13U are caused by the tension of the endless chain 17. , 13L may be misaligned, the support rigidity may be reduced, and problems such as bending of the first balancer shaft 11 and vibration of the driven sprocket 16 may not be satisfactorily suppressed.

  On the other hand, since the first bearing portion 31 (32, 33) has a half structure (32U, 33U: 32L, 33L) provided in the upper case 13U and the lower case 13L, the balancer shafts 11, 12 are connected to the case member 13. The insertion distance (horizontal stroke distance) of the balancer shafts 11 and 12 with respect to the second bearing portion 34 when housed in the housing is shortened, and the case member 13 can be made compact. On the other hand, when the first bearing portion 31, particularly the front bearing portion 32, has a hole structure integrally provided in the case member 13 like the second bearing portion 34 from the beginning, the front end portion of the first balancer shaft 11 ( The insertion distance for moving the shaft extension portion journal portion 150) to the position of the second bearing portion 34 becomes longer, and accordingly, the case member 130 needs to be lengthened in the axial direction, and the case member 130 can be made compact. It will be disturbed.

  In particular, as apparent from FIG. 6 and the like, for example, as shown in FIG. 6 and the like, the interlocking gears 23 and 23 having a diameter larger than that of the weight portions 21 and 22 are present on the balancer shafts 11 and 12. When this is inserted, the case member 13 needs a space (gear non-interference space) 120 that does not hinder the movement of the interlocking gears 23 and 23 in the axial direction. Therefore, as the insertion distance of the balancer shafts 11 and 12 becomes longer, the gear non-interference space 120 that is unnecessary and wasted after assembling occupies a large space in the lower part of the engine block 2 and reduces layout performance. End up.

  Next, since the case extension portion 41 and the second bearing portion 34 are provided on the upper case 13U directly coupled to the engine block 2 in the upper case 13U and the lower case 13L, the support of the second bearing portion 34 is provided. The rigidity is further increased, and the support of the shaft extension 26 of the first balancer shaft 11 is further stabilized.

  Next, the thrust restricting portion 78 of the balancer shafts 11 and 12 resulting from the rotation of the helical gears constituting the interlocking gears 23 and 23 is provided only in the lower case 13L where the case extension 41 and the second bearing portion 34 are not provided. Therefore, the structure of the thrust restricting portion 78 is simplified, and the weight of the case member 130 can be reduced.

  The embodiment described above is the best mode for carrying out the present invention, but it goes without saying that various modifications can be made without departing from the scope of the claims.

  According to the present invention, the first balancer shaft can be firmly and rotatably supported in the vicinity of the driven sprocket, and as a result, the first balancer shaft is bent by the shaft extension portion and the driven sprocket vibrates. This avoids the problem of vibration and noise caused by the balancer device. The present invention has wide industrial applicability in the technical field of engine balancer devices.

It is the figure which looked at the main body of the engine which concerns on the best form for implementing this invention from the front side, after removing a chain cover. It is the elements on larger scale which looked at the state where the bearing frame and the case member of the balancer device were respectively attached to the lower part of the cylinder block of the above-mentioned engine body from the front side (however, crankshaft, sprocket, endless chain, support bracket, Pumps etc. have been removed). It is the lower surface (mating surface with a lower case) figure of the upper case which comprises the upper half part of the said case member, Comprising: It is seen in the arrow A direction of the said FIG. FIG. 4 is a top view (a mating surface with the upper case) of the lower case constituting the lower half of the case member, as viewed in the direction of the arrow c in FIG. 2. FIG. 4 is a bottom view similar to FIG. 3, showing an initial stage of work for accommodating the balancer shaft in the upper case. FIG. 6 is a bottom view similar to FIG. 5 showing the final stage of the work of accommodating the balancer shaft in the upper case. FIG. 7 is a bottom view similar to FIG. 6 of a case member in which a lower case is brought into contact with an upper case in which the balancer shaft is accommodated and coupled with a bolt. FIG. 3 is a partial longitudinal sectional view taken along the line of FIG. 2 (however, a crankshaft, a sprocket, an endless chain, a support bracket, etc. are attached). FIG. 9 is an enlarged view of a main part of FIG. 8, showing a state in which a tip end portion of a case extension portion of a case member is supported by a support bracket attached to a front side surface of a bearing frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Engine block 4 Cylinder block 5 Bearing frame 6 Crankshaft 7 Oil pan 10 Balancer device 11 1st balancer shaft 12 2nd balancer shaft 13 Case member 13U Upper case 13L Lower case 15 Drive sprocket 16 Driven sprocket 17 Endless chain 18 Oil pump 21 Front Weight Part 22 Rear Weight Part 23 Interlocking Gear 24 Rear Journal Part 25 Front Journal Part 26 Shaft Extension Part 31 First Bearing Part 32 Front Bearing Part 33 Rear Bearing Part 32U, 33U: 32L, 33L First Bearing Part 34 Second bearing portion 41 Case extension portion 51 Support bracket 52, 53, 54 Bolt 62, 63, 64 Seat 71 Penetration member (color member)
72 Bolt 72a Screw hole 75,76 Guide part 77 Tensioner 78 Thrust restricting part 90 Lubricating oil path 92 Oil inlet 98U, 99U Upper concave groove 98L, 99L Lower concave groove 150 Shaft extension part journal part

Claims (4)

  The first and second balancer shafts each having a weight portion and rotating together, and a case member that is attached to a lower portion of the engine block that supports the crankshaft and supports the balancer shaft, A balancer device for an engine having a configuration in which a winding transmission member is wound around a driving side rotating body attached to one end and a driven side rotating body attached to one end of the first balancer shaft, The shaft has interlocking gears that mesh with each other on the one end side with respect to the weight portion, and the first balancer shaft has a shaft extension that extends longer on the one end side than the second balancer shaft, The driven-side rotating body is attached to the shaft extension, and the case member is a first bearing for bearing the balancer shaft in the vicinity of the weight portion and the interlocking gear. And a second bearing portion for bearing the first balancer shaft in the vicinity of the driven-side rotor, and the case member is connected to the engine block and the upper case. A lower case that is in contact with each other, and one of these cases is provided with a case extension that extends long on the one end side, and the first bearing portion is a pair of halved portions provided in the two cases. An engine balancer device comprising: a hole formed in contact, wherein the second bearing portion is formed by a hole provided integrally with the case extension.   The balancer device for an engine according to claim 1, wherein the case extension portion and the second bearing portion are provided in the upper case.   The interlocking gear is composed of a helical gear, and the thrust force acting on the balancer shaft by the rotation of the helical gear is received only in the upper case and the lower case where the case extension portion and the second bearing portion are not provided. The balancer device for an engine according to claim 1, wherein a convex portion is provided. The case member has a sealed structure that does not expose the weight portion of the balancer shaft, and a lubricating oil passage that supplies lubricating oil to the first and second bearing portions provided in the case member constitutes the case member. The balancer device for an engine according to any one of claims 1 to 3, wherein the balancer device is formed inside a wall portion.

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