JP2008256161A - Balancer device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a balancer device for an engine capable of effectively canceling the vertical vibration of an engine body without enhancing the rigidity of a housing by immoderately increasing a wall thickness. <P>SOLUTION: In the balancer device 2 for the engine, the housing 22 for rotatably pivoting a pair of balancer shafts 21L, 21R in parallel with a crank shaft 14 is fastened with a lower part of the engine body 1 in which a plurality of cylinders 1a are arranged in a row with bolts 24, 25. The housing 22 is fastened with a lower surface 10b outside both the balancer shafts 21L, 21R in a width direction with the bolts 24, 24 and also fastened with the lower surface 10b between both the balancer shafts 21L, 21R with the bolt 25. The housing 22 is fastened with the lower surface 10b corresponding to a position of a bearing 13 (a semicircular part 10a) with the bolt 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine balancer device in which a housing, in which a pair of balancer shafts are rotatably supported in parallel to a crankshaft, is fastened by a fastening member at a lower portion of an engine body in which a plurality of cylinders are arranged in a row.

  In engines for automobiles and the like, a balancer device may be provided in order to suppress generation of vibration and noise. The balancer device generally has a balancer shaft arranged in parallel to a crankshaft supported by a bearing member.

  The balancer shaft is connected to the crankshaft by a gear device or the like, and is driven to rotate in synchronization with the crankshaft. A moment is generated by the rotation of the unbalanced mass section that is offset from the axis of the balancer shaft, and this moment cancels out the vertical vibrations of the engine body caused by the explosion of each cylinder, reducing noise. To do.

  By the way, this balancer device may be provided such that the balancer shaft is positioned below the crankshaft. The balancer device is a unit in which the housings are fastened together with the balancer shaft supported by the upper housing and the lower housing. And the housing of the balancer device is fastened to the lower part of the engine main body in which a plurality of cylinders are arranged in a row with a bolt different from the bolt for fastening the housings together, and the balancer shaft is rotatable within the housing. It is pivotally supported.

  The housing is fastened on the outside in the width direction of both balancer shafts, and the balancer device is supported so as to be suspended from the engine body on both sides in the width direction of the housing.

  However, in this case, the central portion in the width direction of the housing is not supported. For this reason, when the rigidity of the housing is low, the housing starts to bend and deform up and down as the balancer shaft rotates due to the increased rotation of the engine.

  At this time, the balancer device adds a new vibration, the vertical vibration of the housing, and therefore the vertical vibration cycle in the balancer device is not synchronized with the vertical vibration cycle of the engine body. Will not be able to cancel out enough.

  In recent years, there has been a demand for quietness in the low engine speed range, and in connection with this, it is considered that quietness in the high speed range is required. Therefore, suppressing the vertical vibration of the housing is indispensable for improving the quietness of the engine.

  By the way, such vertical vibration of the housing can be suppressed by increasing the rigidity of the housing by increasing the thickness of the housing or forming a rib.

  For example, in the following Patent Document 1, the housing of the balancer device has a structure having a plurality of bearing wall portions for the balancer shaft. In this case, the bearing wall portion plays a role like a beam, which increases the rigidity of the housing.

JP 2003-130136 A

  However, in the balancer device disclosed in Patent Document 1, since the bearing wall portion is formed so as to extend higher toward the engine body side, the weight of the housing is increased by that amount. It would be a disadvantageous structure.

  In addition, since this housing is structured such that only the outer side in the width direction is fastened and the central portion is not supported, the vertical vibration of the engine cannot be sufficiently canceled out.

  An object of the present invention is to provide an engine balancer device that can effectively cancel the vertical vibration of the engine body without increasing the thickness unnecessarily in order to improve the rigidity of the housing.

  An engine balancer device according to the present invention includes an engine balancer device in which a housing in which a pair of balancer shafts are rotatably supported in parallel with a crankshaft is fastened by a fastening member at a lower portion of an engine body in which a plurality of cylinders are arranged in a row. The fastening member fastens the housing on the outer side in the width direction of both balancer shafts, and the second fastening fastens the housing to the bearing member of the crankshaft between the balancer shafts. Member.

  According to this structure, the increase in the vertical vibration of the housing accompanying the rotation increase of the balancer shaft can be reliably received by the second fastening member.

  For this reason, it is possible to suppress the phenomenon that the vertical vibration cycle in the balancer device is not synchronized with the vertical vibration cycle on the engine body side, and the vertical vibration of the engine body can be reduced without increasing the thickness unnecessarily to improve housing rigidity. Can be effectively counteracted.

  In one embodiment of the present invention, the housing is made of a light alloy.

  In this case, since the rigidity is reduced as compared with the case of cast iron, the housing is more likely to vibrate up and down. According to this configuration, the effect of fastening the second fastening member becomes more remarkable.

  In one embodiment of the present invention, the housing includes a halved upper housing and a lower housing, and the first and second fastening members fasten the upper and the lower housing together. .

  According to this configuration, the second fastening member can also be used as a fastening member for assembling the housing.

  In an embodiment of the present invention, at least one second fastening member is disposed corresponding to the vicinity of the unbalance mass portion that the balancer shaft has at a predetermined position in the axial direction.

  According to this configuration, since the second fastening member can be brought close to the source of the vertical vibration of the housing, the vertical vibration of the housing can be received more effectively.

  In one embodiment of the present invention, the housing is fastened to the lower surface side of the bearing member by the second fastening member, and the bearing member includes a portion to be fastened on the lower surface side and a semicircle with respect to the crankshaft. An opening for stress relaxation is provided between the arc-shaped bearing surface portion.

  According to this configuration, when the vertical vibration of the housing increases with the rotation of the balancer shaft, the energy of the vertical vibration can be mitigated from being transmitted as stress to the bearing surface portion via the second fastening member. For this reason, it can prevent that the vertical vibration of a housing inhibits the bearing performance of a crankshaft.

  In one embodiment of the present invention, the shape of the opening is a shape having roundness without corners.

  According to this configuration, the stress can be prevented from concentrating on one point (corner) at the periphery of the opening, so that the bearing member can be prevented from being damaged at the periphery of the opening.

  According to the present invention, since the increase in the vertical vibration of the housing accompanying the increase in the rotation of the balancer shaft can be reliably received by the second fastening member, the engine can be used without increasing the thickness unnecessarily to improve the housing rigidity. The vertical vibration of the main body can be effectively canceled out.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a bottom view showing a lower structure of an engine according to an embodiment of the present invention. FIGS. 2 and 3 are cross-sectional views taken along line AA and BB, respectively, in FIG. It is. As shown in FIG. 1, the engine according to the present embodiment has an engine body 1 in which a plurality of cylinders 1 a,... 1 a are arranged in a row, and the engine body 1 is, as shown in FIG. The lower block 10 and the upper block 11 are formed by fastening with a plurality of bolts 12. In the figure, the direction is indicated using arrows (front) and arrows (rear), but this indicates the direction of the engine main body, and “front” and “rear” in this specification are , Arrow (front), arrow (rear).

  The lower block 10 and the upper block 11 have semicircular arc portions 10a and 11a as shown in FIG. 2 corresponding to the positions fastened by the bolts 12,. And the bearing part 13 is comprised by multiple (here 5 pieces) by the combination of these semicircular arc shaped parts 10a and 11a. The crankshaft 14 is rotatably supported by the bearing portion 13.

  In the present embodiment, one cylinder 1a is arranged between the two bearing portions 13 and 13. In the illustrated example, four cylinders 1a arranged in this way are arranged in series. This is a so-called in-line four-cylinder gasoline engine.

  In the engine according to the present embodiment, as shown in FIGS. 1 to 3, the balancer device 2, the oil pump 3, and the oil pan 4 are attached to the lower surface portion 10 b of the lower block 10. 1 and 3 show a state where the oil pan 4 is removed for convenience of explanation.

  As shown in FIG. 2, the balancer device 2 includes a housing 22 that rotatably supports a pair of balancer shafts 21L and 21R. The housing 22 is made of, for example, a light alloy such as aluminum, and is configured by fastening a halved upper housing 22U and a lower housing 22L with a plurality of bolts 23 to 25 as shown in the figure.

  Each balancer shaft 21L, 21R is disposed below and parallel to the crankshaft 14, and its axis L, R is a vertical plane passing through the axis Y of the crankshaft 14 (one point in FIG. 2). (Indicated by a chain line) and are arranged symmetrically in the same horizontal plane.

  Further, the balancer shafts 21L and 21R have unbalanced mass portions 21a and 21a whose center of gravity is offset from the axial centers L and R at predetermined positions in the axial direction, and between the two unbalanced mass portions 21a and 21a. It is supported by a bearing portion 26 (see FIG. 3) of the housing 22. Both unbalanced mass portions 21a, 21a are always located at the same height during rotation of the balancer shafts 21L, 21R.

  By the way, in this embodiment, the balancer apparatus 2 is fastened and integrated with the oil pump 3. In this case, when the balancer device 2 and the oil pump 3 are assembled to the engine body 1, first, the balancer device 2 and the oil pump 3 are assembled (fastened), and then the lower surface portion 10 b of the lower block 10. Install at once.

  At this time, as shown in FIG. 1, the balancer device 2 side is fastened by bolts 24, 24, 25 at the center of the engine body 1 in the cylinder row direction, and the oil pump 3 side is bolted at the front end of the engine body 1. It is fastened by 31 and 31. Thus, the balancer device 2 and the oil pump 3 are supported so as to be suspended from the engine body 1.

  In particular, in the balancer device 2, the housing 22 is fastened to the lower surface portion 10b on the outer side in the width direction of the balancer shafts 21L and 21R by bolts 24 and 24, and the lower surface is also formed between the balancer shafts 21L and 21R by the bolt 25. Fastened to the portion 10b.

  Here, the housing 22 is fastened to the lower surface portion 10b corresponding to the position of the bearing portion 13 (semi-arc-shaped portion 10a) by bolts 25 as shown in FIGS.

  As shown in FIG. 3, one bolt 25 is disposed corresponding to the vicinity of the unbalance mass portion 21 a of the balancer shaft 21 </ b> L (21 </ b> R).

  By the way, in this embodiment, in the lower block 10, an opening 10 c is formed between a portion to be fastened on the lower surface portion 10 b to which the bolt 25 is fastened and a semicircular arc-shaped portion 10 a corresponding to the crankshaft 14. And the front-end | tip of the volt | bolt 25 protrudes in the space part formed of the opening part 10c.

  The opening 10c is a long hole extending in the width direction of the engine body 1, and both ends thereof are semicircular. Thereby, the shape of the opening part 10c becomes a shape with the roundness without a corner | angular part over the perimeter.

  A sprocket (not shown) connected to the crankshaft 14 via a chain (not shown) is disposed in front of the engine, and the sprocket is a drive shaft 27 (see FIG. 1) extending in the cylinder row direction. ) At one end.

  With such a configuration, the rotational drive of the crankshaft 14 is transmitted to the oil pump 3 and the balancer device 2 via the chain, the sprocket, and the drive shaft 27.

  In particular, the balancer device 2 is provided with a driven gear (not shown) on one balancer shaft (here, the balancer shaft 21R), and a drive gear (not shown) provided on the other end of the drive shaft 27. The drive force transmission unit 28 is engaged.

  Furthermore, an interlocking gear (not shown) is provided at one end of the balancer shafts 21L and 21R, and meshes with each other. As a result, the balancer shafts 21L and 21R are driven to rotate in opposite directions in synchronization with the crankshaft 14.

  At this time, in the present embodiment, since the central portion in the width direction of the housing 22 is fastened to the lower surface portion 10b between the balancer shafts 21L and 21R, the upper and lower sides of the housing 22 accompanying the rotation rise of the balancer shafts 21L and 21R. The increase in vibration can be reliably received by the bolt 25.

  For this reason, the phenomenon that the vertical vibration cycle in the balancer device 2 is not synchronized with the vertical vibration cycle on the engine body 1 side can be suppressed, and even if the thickness of the engine is not increased unnecessarily in order to improve the housing rigidity, The vertical vibration of the engine body 1 in the rotation range can be effectively canceled out.

  Further, when the housing 22 is made of a light alloy as in this embodiment, the rigidity is lower than that of a cast iron, so that it should be easier to vibrate up and down. Therefore, the effect of fastening the bolt 25 becomes more prominent when the housing 22 is made of a light alloy. Further, even if the housing 22 is made of a light alloy, the vertical vibrations of the engine body 1 can be effectively canceled out, so that the housing 22 can be reduced in weight and the entire engine can be reduced in weight.

  Further, since the upper housing 22U and the lower housing 22L are fastened together with the bolt 25, the bolt 25 can also be used as a bolt for assembling the housing 22.

  The vertical vibration source of the housing 22 is mainly in the vicinity of the unbalanced mass portions 21a and 21a of the balancer shafts 21L and 21R. Therefore, as in the present embodiment, the bolt 25 can be brought close to the source of the vertical vibration by arranging the bolt 25 in the vicinity of the unbalanced mass portions 21a, 21a. Vibration can be received more effectively.

  Further, in the lower block 10, the balancer shafts 21 </ b> L and 21 </ b> R are increased in rotation by forming an opening 10 c between the fastened portion of the lower surface portion 10 b to which the bolt 25 is fastened and the semicircular arc portion 10 a. Accordingly, when the vertical vibration of the housing 22 increases, the energy of the vertical vibration can be mitigated from being transmitted as stress to the semicircular arc portion 10 a via the bolt 25. For this reason, it is possible to prevent the vertical vibration of the housing 22 from inhibiting the bearing performance of the crankshaft 14.

  In addition, since the shape of the opening 10c has a round shape with no corners, the stress can be prevented from concentrating on one point (corner) of the periphery of the opening 10c. The cylinder block 10 can be prevented from being damaged.

  The shape of the opening 10c is not necessarily limited to that shown in FIG. For example, it may be a long hole having arcuate portions at four corners, such as an opening 10c 'shown in FIG. Moreover, an elliptical shape may be sufficient like opening 10c '' shown in FIG.4 (b).

  In the embodiment shown in FIGS. 1 to 3, the housing 22 is fastened by one bolt 25 between the balancer shafts 21 </ b> L and 21 </ b> R. However, the present invention is not necessarily limited to this. For example, a plurality (two in this case) may be fastened by two bolts 75 and 75 as in a housing 72 shown in FIG. In FIG. 5, the same components as those in the embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the balancer device 52 shown in FIG. 5, the front and rear ends of the housing 72 are fastened to the lower surface portion 10b on the outer side in the width direction of both balancer shafts (not shown here) by bolts 74,. As a result, it is fastened to the lower surface portion 10b even between both balancer shafts.

  That is, the housing 72 is fastened at a total of four locations on the outer side in the width direction of both balancer shafts by the bolts 74... 74 and is fastened at a total of two locations between the balancer shafts by the bolts 75 and 75.

  Here, the housing 72 is fastened to the lower surface portion 10b corresponding to the position of the bearing portion 13 (semi-arc-shaped portion 10a) by the bolt 75, as in the embodiment shown in FIGS.

  Thereby, the increase in the vertical vibration of the housing 72 can be received by the two bolts 75, and the vertical vibration of the engine body 1 can be canceled more effectively.

  5 are bolts for fastening the upper housing and the lower housing of the housing 72 together, and the operation thereof is the same as that of the bolt 23 shown in FIGS.

  Further, a member 53 indicated by a two-dot chain line in the drawing is an oil pump integrated with the balancer device 52, and here, the oil pump 53 is located behind the balancer device 52. However, the present invention is not limited to this, and the oil pump 53 may be positioned in front of the balancer device 52.

  Also in the embodiment shown in FIG. 5, other operational effects are the same as those in the embodiment shown in FIGS. 1 to 3.

In correspondence between the configuration of the present invention and the above-described embodiment,
The first fastening member of the present invention corresponds to the bolts 24 and 74,
Similarly,
The second fastening member corresponds to the bolts 25 and 75,
The bearing member corresponds to the lower block 10,
The bearing surface portion corresponds to the semicircular arc-shaped portion 10a,
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

The bottom view which shows the lower structure of the engine which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is a cross-sectional view taken along line B-B in FIG. 1. The principal part enlarged view which shows other embodiment of an opening part. The bottom view which shows the lower structure of the engine which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine main body 2, 52 ... Balancer apparatus 10 ... Lower block 10a ... Semi-arc shaped part 12, 23, 24, 25, 31, 73, 74, 75 ... Bolt 14 ... Crankshaft 21L, 21R ... Balancer shaft 21a ... Unloader Balance mass part 22, 72 ... Housing 22U ... Upper housing 22L ... Lower housing

Claims (6)

An engine balancer device in which a housing in which a pair of balancer shafts are rotatably supported in parallel with a crankshaft is fastened by a fastening member at a lower portion of an engine body in which a plurality of cylinders are arranged in a row,
A first fastening member for fastening the housing on the outer side in the width direction of both balancer shafts;
A balancer device for an engine including a second fastening member for fastening the housing to a bearing member of the crankshaft between both balancer shafts. The balancer device for an engine according to claim 1, wherein the housing is made of a light alloy. The balancer device for an engine according to claim 1 or 2, wherein the housing includes a half-shaped upper housing and a lower housing, and the first and second fastening members fasten the upper and the lower housing together. The balancer device for an engine according to any one of claims 1 to 3, wherein at least one of the second fastening members is disposed in the vicinity of an unbalanced mass portion that the balancer shaft has at a predetermined position in the axial direction. . The housing is fastened to the lower surface side of the bearing member by the second fastening member,
The bearing member is provided with an opening for stress relaxation between a portion to be fastened on the lower surface side and a semicircular bearing surface portion with respect to the crankshaft. The balancer device for the engine described in 1. The balancer device for an engine according to claim 5, wherein the shape of the opening is a shape having roundness without corners.

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