JP4658265B2 - Engine balancing device - Google Patents

Description

  The present invention relates to an engine balancing device including a housing that rotatably receives a balancer shaft.

  There is known a balancing device in which a balancer shaft is disposed below a crankshaft in an oil pan and the rotation of the crankshaft is transmitted to the balancer shaft via a chain / sprocket mechanism, a gear mechanism, or the like (Patent Document 1). See).

  What is disclosed in the above document is an oil strainer, an oil pump, and a suction passage that connects between the oil strainer and the oil pump in a housing that rotatably receives a balancer shaft for canceling the vibration generated by the piston. Are provided integrally.

On the other hand, in the oil supply passage, it is necessary to provide a relief valve for keeping the discharge pressure of the oil pump within a certain range, and this relief valve is generally provided integrally with the housing of the oil pump. (See Patent Document 2).
JP 2001-74105 A JP 2000-199413 A

  In integrally forming the oil strainer mounting portion in the balancing device, it is desirable to avoid as much as possible the size of the device and the complexity of the oil passage configuration. In addition, it is desirable to suppress the increase in weight as much as possible while securing the rigidity of the bearing of the balancer shaft.

  The present invention has been devised to satisfy such demands, and its main purpose is to increase the bearing rigidity of the balancer shaft without increasing the size, complicating the oil passage structure, or increasing the weight. An object of the present invention is to provide an engine balancing device that can be enhanced.

In order to solve such a problem, a first aspect of the present invention has a housing in which a balancer shaft is rotatably received and a mounting boss for attaching an oil strainer is integrally formed on the bottom wall thereof, and a fastening bolt The engine balance device is bolted to the engine block by an oil pump provided at one end of the balancer shaft, and the oil pump extends on one side wall of the housing in the axial direction of the balancer shaft. A tubular passage for connecting the oil passage and the oil strainer is integrally formed, and the mounting boss has a cylindrical shape and is integrally formed on the bottom wall on the upstream end side of the tubular passage. on the side of the downstream end of the tubular passage, fastening boss said fastening bolt is inserted is integrally formed, said mounting board The outer peripheral portion of the shall, characterized in that connected to the bearing wall for supporting the balance shafts. In particular, the oil pump is installed in a pump cover attached to an end surface of the housing on the downstream end side of the tubular passage, and the tubular passage, the oil pump, good assuming that the suction passage communicating are formed (claim 2).

Thus, according to the first aspect of the present invention, it is effective in enhancing the bearing rigidity of the balancer shaft .

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  1 and 2 show a mounting portion of a balance device in a reciprocating piston engine to which the present invention is applied. The engine E is an in-line four-cylinder engine in which the crankshaft 1 extends in the horizontal direction, and includes a cylinder block 2, a lower block 3, a balancing device 4, and an oil pan 5. The cylinder axis is inclined with respect to the orthogonal direction and mounted on the vehicle body.

  The balancing device 4 is for reducing the secondary vibration of the engine E caused by the reciprocating motion of the piston. The balancing device 4 is attached to the oil pan 5 by through bolts B1 inserted into the left and right side ends from below. The inner block is fastened to the lower surface of the lower block 3 (below the crankshaft 1). The balancing device 4 includes a large sprocket 7 fixed to the back side of the crank pulley 6 at the front end of the crankshaft 1 (hereinafter referred to as the crank pulley side), and the left side (hereinafter, the left and right direction toward the crank pulley). And a small sprocket 8 fixed to the front end of a balancer shaft (to be described in detail later) and a link chain 9 spanned between the large and small sprockets 6 and 7. The crankshaft 1 is driven to rotate by the rotational force of the crankshaft 1.

  The balancing device 4 includes a pair of left and right balancer shafts 13L and 13R having substantially the same shape, and the center of both balancer shafts 13L and 13R so as to support and accommodate these two balancer shafts 13L and 13R in parallel with each other. 14U, and an upper housing 14U and a lower housing 14L which are divided into two vertically along a plane passing therethrough.

  Both the balancer shafts 13L and 13R are linked to each other by a helical gear 15 (only one of which is shown) integrally coupled to the balancer shafts 13L and 13R. Here, as described above, the driving force of the crankshaft 1 is transmitted to the left balancer shaft 13L via the large sprocket 7, the small sprocket 8, and the link chain 9, and thus the rotational speed twice that of the crankshaft 1 is achieved. Thus, the left balancer shaft 13L is rotationally driven in the same direction as the crankshaft 1. The right balancer shaft 13R is rotationally driven in the opposite direction by the meshing of the helical gears 15.

  On both balancer shafts 13L and 13R, first and second journal portions 16a and 16b having a relatively small diameter are disposed in front of the helical gear 15, and third and fourth journal portions 16c and 16d having relatively large diameters are disposed at the rear thereof. Each is integrally formed. In addition, a counterweight part 17 is integrally formed at the rear part of each balancer shaft 13L and 13R, the position of the center of gravity being biased radially outward from the center of rotation, and being divided into two front and rear parts with the third journal part 16c interposed therebetween. Has been.

  Flange portions 18 having an enlarged diameter are formed at opposing ends of the front / rear counterweight portion 17 across the third journal portion 16c. Thrust receiving surfaces 19 are formed on the opposing end surfaces of the flange portions 18.

  The shaft portion 20 of the counterweight portion 17 has a relatively small diameter in order to obtain the expected equivalent rotational mass while making the counterweight portion 17 as small as possible. In order to compensate for the decrease in rigidity due to the reduced diameter, it is provided between the mounting portion of the helical gear 15 and the flange portion 18 provided on the front side of the third journal portion 16c and on the rear side of the third journal portion 16c. A rib 21 that connects the flange portion 18 and the fourth journal portion 16d in the axial direction is provided on a portion of the two shaft portions 20 that extends over the entire length on the opposite weight side. These ribs 21 are tapered so that the height dimension is reduced toward the center in the axial direction of each counterweight portion 17 in order to minimize the increase in weight due to the provision of the ribs 21 and to optimize the stress distribution. It is made into a shape.

  On the other hand, the journal portions 16a to 16d of both the balancer shafts 13L and 13R are supported by two divided first to fourth bearing holes 22a to 22d formed by joining the upper and lower housings 14U and 14L to each other. Is done.

  The journal portions 16a to 16d of the balancer shafts 13L and 13R are respectively placed on the half of the bearing holes 22a to 22d on the side of the lower housing 14L, and in this state, the upper housing 14U side of the bearing holes 22a to 22d is placed. The upper and lower housings 14U and 14L are joined to each other by aligning the halved portion of the upper and lower housings 14a to 16d with the journal portions 16a to 16d of the balancer shafts 13L and 13R. It will be rotatably accommodated in 14L. The thrust receiving surface 19 contacts the front and rear end surfaces of the bearing wall 23c in which the third bearing hole 22c is formed to receive the thrust force.

  As shown in FIG. 3, the upper and lower housings 14U and 14L are each provided with a plurality of bolts B2 inserted from above at appropriate positions, and third and fourth bearing holes 22c and 22d. It is fastened with three bolts B3 that pass through the walls 23c and 23d and are inserted from below. In particular, the parts of the bearing walls 23c and 23d on which radial acceleration due to the rotation of the counterweight portion 17 acts are loosened. It is considered that it becomes difficult to occur.

  A pump cover 24 for bolting a trochoid oil pump (detailed later) for pumping oil to various parts of the engine is bolted to the front end surface of the lower housing 14L. This oil pump is provided at the shaft end of the right balancer shaft 13R. When the right balancer shaft 13R rotates, the oil pump is installed on one side wall of the lower housing 14L from an oil strainer 25 attached to the bottom wall of the lower housing 14L. The oil in the oil pan 5 is sucked through the tubular passage 26 on the upstream side of the suction passage and is pumped to various parts of the engine.

  The mounting boss 28 of the strainer cover 27 that holds the oil strainer 25 is integrally formed on the lower side of the two balancer shafts in the lower housing 14L, that is, on the lower position of the left balancer shaft 13L. The mounting boss 28 has a substantially cylindrical shape, and the bolt provided between the two balancer shafts 13L and 13R of the bolt B3 for fastening the upper housing 14U and the lower housing 14L to each other and the lower side thereof. The center of the left balancer shaft 13L is arranged between the bolts provided on the outer side of the left balancer shaft 13L, and the bearing wall 23c provided with a half portion of the third bearing hole 22c in the middle portion in the front-rear direction of the lower housing 14L The outer periphery is connected. This enhances the rigidity of the bearing wall 23c that fastens the upper housing 14U and the lower housing 14L. Further, the tubular passage 26 integrally formed on one side wall of the lower housing 14 </ b> L reaches the end of the joint surface of the pump plate 24.

  A fastening boss 30 for inserting a fastening bolt B1 with respect to the lower block 3 is provided at a position adjacent to the side of the end portion of the tubular passage 26, which contributes to increasing the fastening rigidity of the balancing device 4 with respect to the lower block 3. is doing.

  As described above, the oil strainer 25 is mounted directly below the left balancer shaft 13L on the lower side of the two balancer shafts on the bottom wall of the lower housing 14L, and is close to the vertical plane passing through the center of the crankshaft 1. The center of the engine E is located directly below the center of gravity of the engine E. In this way, the suction port 29 of the strainer cover 27 is positioned at a position where the oil level fluctuation is smallest in the lowermost bottom portion of the oil pan 5 without greatly extending the strainer mounting boss 28 downward. Therefore, even if the oil level fluctuates due to longitudinal acceleration or centrifugal force during traveling, the oil suction does not deteriorate.

  As shown in FIGS. 4 and 5, the joint surface of the lower housing 14 </ b> L with the above-described pump cover 24 has a suction passage 41 opened at the downstream end of the tubular passage 26 that is an outlet portion from the oil strainer 25. A pump chamber 43 for receiving the oil pump 42, a discharge passage 44 connected to an oil supply passage (not shown) provided in the lower block 3, and a relief passage branched from the discharge passage 44 to the relief valve 45 46 and a return passage 47 that recirculates excess pressure from the relief valve 45 to the suction passage 41 is formed.

  The oil pump 42 is a known trochoid pump including an outer rotor 48 rotatably received in the pump chamber 43 and an inner rotor 50 connected to the front end of the right balancer shaft 13R via a coupling 49. 51 is supported by a pump bearing hole 52 provided in the wall 43 w of the pump chamber 43.

  As shown in FIG. 6, a valve chamber 53 having a cylindrical hole for receiving the relief valve 45 is provided at the bottom of the front end portion of the lower housing 14 </ b> L. The relief valve 45 is a known plunger valve, is slidably fitted into a valve chamber 53 drilled by a drill, and is constantly urged by a coil spring 54 in the valve closing direction. And the discharge pressure of the oil pump 42 is introduced into the right end.

  As described above, on the right balancer shaft 13R side of the two balancer shafts in the lower housing, the downstream portion of the suction passage 41 and the valve chamber 53 serving as the receiving portion of the relief valve 45 are provided, and the right balancer shaft Since the pump chamber 43, which is the receiving portion of the oil pump, is provided on the axis of 13R, these are centrally arranged on one balancer shaft side, so that the oil passage configuration can be simplified and the entire apparatus can be made compact. Can contribute.

  When the oil pump 42 rotates together with the right balancer shaft 16R, the oil that flows into the suction passage 41 through the oil strainer 25 and the tubular passage 26 is pressurized by the oil pump 42 and discharged to the discharge passage 44. And it is pumped to the oil supply path in the lower block 3 from the discharge port 55 opened on the upper surface of the pump cover 24, and is supplied to each part of the engine.

  At this time, the oil branched from the discharge passage 44 and flowing into the relief passage 46 applies hydraulic pressure to the right end of the relief valve 45. When this hydraulic pressure exceeds the pressing force of the coil spring 54 energizing the relief valve 45, the relief valve 45 moves in the valve opening direction and is connected to an appropriate position in the valve chamber 53 (see FIG. 7). ) Oil flows back from the return passage 47 to the suction passage 41, and the discharge pressure is kept within a certain range.

  As shown in FIGS. 3 and 4, the valve chamber 53 that has received the relief valve 45 is an oil that is perpendicular to the axis of the tubular passage 26 extending from the oil strainer 25 and offset downward, that is, oil in the suction passage. It is provided at a position avoiding the extension line of the exit portion from the strainer 25 so as not to interfere with the tubular passage 26. As a result, the oil passage configuration can be simplified without impairing the mountability of the relief valve 45, and it contributes to the compactness of the entire apparatus.

  The valve chamber 53 that has received the relief valve 45 is a second chamber that supports the front end wall 43w of the lower housing 14L in which the bearing holes 32 of the pump chamber 43 and the pump shaft 51 are formed, and the journal portion 16b of the front end of the right balancer shaft 13R. The bearing wall 23b is connected to both the front end wall 43w and the second bearing wall 23b. As a result, the relief valve 45 can be arranged in a compact manner by utilizing the space between the front end wall 43w and the second bearing wall 23b, and the valve chamber 53 can be used as a reinforcing member for the second bearing wall 23b and the pump. It can be used as a reinforcing member for the chamber 43 and the bearing hole 32 of the pump shaft 51.

  In addition, if the oil supply path 56 to the chain tensioner etc. which was attached to the pump cover is provided in the position enclosed by the valve chamber 53 as a receiving part of the pump chamber 43, the relief passage 46, and the relief valve 45, for example, An oil supply passage to other members can be formed without effectively increasing the size of the housing by effectively utilizing the dead space.

It is the front sectional view which cut away and represented the principal part of the engine to which this invention was applied. It is a partial sectional side view which follows the II-II line | wire in FIG. It is a bottom view of the lower housing of a balancing device. It is a front view of the lower housing of a balancing apparatus. FIG. 5 is a partial cross-sectional view taken along line VV in FIG. 4. It is a fragmentary sectional view which follows the VI-VI line in FIG. It is a fragmentary sectional view which follows the VII-VII line in FIG.

Explanation of symbols

4 Balancer 13L / 13R Balancer shaft 14U Upper housing 14L Lower housing 23c Bearing wall 25 Oil strainer 27 Strainer cover 28 Mounting boss

Claims (2)

A balance device for an engine which rotatably receives a balancer shaft and has a housing integrally formed with a mounting boss for mounting an oil strainer on a bottom wall thereof, and is bolted to an engine block by a fastening bolt,
An oil pump is provided at one end of the balancer shaft,
A tubular passage that extends in the axial direction of the balancer shaft and is connected to the oil strainer and the oil pump is integrally formed on one side wall of the housing.
The mounting boss has a cylindrical shape and is integrally formed on the bottom wall on the upstream end side of the tubular passage,
A fastening boss through which the fastening bolt is inserted is integrally formed on the side of the downstream end of the tubular passage in the housing ,
An engine balancing device, wherein an outer peripheral portion of the mounting boss is connected to a bearing wall that supports the balancer shaft . The oil pump is installed in a pump cover attached to an end face on the downstream end side of the tubular passage in the housing,
The joint surface between the pump cover and the housing, wherein the suction passage for communicating the oil pump and the tubular passageway is formed, the balance for engine according to claim 1 device.

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