JP4888814B2 - Balancer device for internal combustion engine - Google Patents

Description

  The present invention relates to an improvement of a balancer device of an internal combustion engine that is applied to, for example, an internal combustion engine for an automobile and reduces the vibration of the engine.

  As a balancer device for an internal combustion engine used in a conventional automobile, one described in Patent Document 1 below is known.

  In brief, the balancer device is disposed in an oil pan provided at a lower position of the cylinder block, and a housing constituted by an upper housing and a lower housing that are bolted to the lower side of the cylinder block; A pair of drive-side and driven-side balancer shafts are provided in the housing so as to be parallel to each other, and are each provided with a balancer weight integrally on one end side in the axial direction.

  The driving side shaft is set to have a longer axial length than the driven side shaft, a driving side gear which is a helical gear is provided at one end portion, and a sprocket is provided at the other end portion. Rotational force is transmitted from the crankshaft through a chain wound around the sprocket and the sprocket at the tip of the crankshaft.

  Further, the drive side shaft has journal portions formed in a relatively large diameter at three positions in the axial direction in the vicinity of both ends of the balancer weight and in the vicinity of the sprocket. Are rotatably supported by bearings provided in the housing with a predetermined clearance.

  On the other hand, the driven side shaft is provided with a driven side gear meshing with the driving side gear at one end, and a rotational force is transmitted from the driving side shaft via the driven side gear, and the driven side shaft is driven with the rotational force. It rotates in the opposite direction with respect to the side shaft.

  Further, the driven shaft has journal portions at two positions in the axial direction in the vicinity of both ends of the balancer weight, and the entire peripheral area of each journal portion is provided in the housing in the same manner as the drive shaft. The bearing portion is rotatably supported.

When the crankshaft is driven to rotate as the engine is started, the drive-side shaft rotates at a rotational speed twice that of the crankshaft via each sprocket and chain, and the centrifugal force of each balancer weight accompanying such rotation To suppress the secondary vibration of the engine.
JP 2003-201912 A

  By the way, the driving shaft is bent and deformed in the vicinity of the position of the balancer weight based on the centrifugal force of the balancer weight. Then, even if both ends of the balancer weight generating the centrifugal force are supported, the bending deformation generated in the vicinity of the balancer weight disposition position through the clearance set in each bearing portion is transferred to another part. It may reach. In this case, in particular, large swinging is caused at the other end portion of the extended drive side shaft.

  Therefore, as in the conventional balancer device, the configuration that supports the entire circumference of the journal portion in the vicinity of the other end portion of the drive-side shaft is configured so that the bending deformation is applied to the journal portion when the bending deformation is applied to the journal portion. There has been a technical problem that deformation causes a large friction loss between the journal portion and the bearing portion.

  The present invention was devised in view of the actual situation of the conventional balancer device, and provides a balancer device for an internal combustion engine that can reduce friction loss generated between the balancer shaft and the bearing portion as much as possible. It is aimed.

  The invention of the present application is characterized in that, in particular, a bearing portion adjacent to the drive rotor is opened on the opposite side to the direction pulled by the tension of the endless transmission member.

  Hereinafter, an embodiment in which an internal combustion engine balancer device according to the present invention is applied to an in-line four-cylinder engine for an automobile will be described with reference to the drawings.

  That is, as shown in FIG. 2, the crankshaft 3 is provided at the lower part of the cylinder block 1 of the engine by a bearing comprising the cylinder block 1 and a bearing cap 2 fastened to the lower part of the cylinder block 1 by bolts. An oil pan 4 that is rotatably supported and stores oil for lubricating each sliding portion of the engine so as to cover the entire lower portion of the cylinder block 1 is attached. A balancer device 5 is integrally formed in the interior of 4.

  A large-diameter crank sprocket 6 is attached to one end of the crankshaft 3 so as to be integrally rotatable, and a balancer, which will be described later, via a chain 7 that is an endless transmission member wound around the crank sprocket 6. A rotational force is transmitted to the sprocket 9. A predetermined tension is applied to the chain 7 via a tension applying mechanism 8 provided on the outer side of the oil pan 4.

  As shown in FIGS. 1 and 2, the balancer device 5 includes an upper housing 10 integrally formed with the oil pan 4, a lower housing 11 attached to a lower portion of the upper housing 10, and both the housings 10, 11. A drive-side drive shaft 12 that is a balance shaft that is rotatably supported between them and arranged in parallel along the axial direction of the crankshaft 3 that is the longitudinal direction of the engine, and a driven-side driven shaft 13 that is driven by the balance shaft; Helical drive gears 14 and driven gears 15 that are fixed to one axial end portions of the shafts 12 and 13 and mesh with each other through the respective tooth portions are provided.

  As shown in FIG. 4, the drive shaft 12 has a longer axial length than the driven shaft 13, and a crankshaft is connected to the other end in the axial direction via a balancer sprocket 9 that is integrally rotatable. 3 rotational force is transmitted. The balancer shaft 12 is restricted from moving in the axial direction by a thrust receiving portion 11 a provided so as to sandwich the drive gear 14 inside the lower housing 11. The drive shaft 12 is configured to rotate in synchronism with the driven shaft 13 via the drive gear 14 and the driven gear 15 and to rotate twice for each rotation of the crankshaft 3.

  Further, as shown in FIGS. 1 and 4, the drive shaft 12 has a large-diameter shape that has substantially the same diameter at three predetermined axial positions from one end side to the other end side in the axial direction. The first journal portion 12a, the second journal portion 12b, and the third journal portion 12c are formed, and a crossing between the axial directions of the first journal portion 12a and the second journal portion 12b as shown in FIG. A substantially half-moon-shaped balancer weight 16 is integrally provided.

  As shown in FIG. 1, the first and second journal portions 12 a and 12 b are both provided at one end side in the axial direction of the drive shaft 12, respectively, The first and second drive-side bearing members 18a, which are plain bearings formed in a substantially half-divided manner in the respective bearings constituted by the first and second drive-side bearing portions 17a, 17b formed in a half-divided shape. , 18b and is supported rotatably with a predetermined clearance.

  The third journal portion 12c is provided in the vicinity of the other end portion in the axial direction of the drive shaft 12, and is substantially the same as the first and second drive side bearing portions 17a and 17b formed only in the upper housing 10. The lower half side in FIG. 1, which is the oil surface side of the oil pan 4, is supported in a freely rotating manner only by the semicircular third drive side bearing portion 17 c. The third journal portion 12c is set so that at least the opened lower half is immersed in the lubricating oil surface in the oil pan 4 when the engine is stopped.

  Furthermore, since the other end of the drive shaft 12 is always pulled toward the side closer to the crankshaft 3 (upward in FIG. 1) by the tension of the chain 7, the third journal portion 12c is a third drive side bearing portion. 17c is always pressed.

  On the other hand, as shown in FIG. 4, the driven shaft 13 has an axial length shorter than that of the drive shaft 12 and is configured in substantially the same manner as one end side portion of the drive shaft 12. Similarly, axial movement is restricted by a thrust receiving portion 11 b provided so as to sandwich the driven gear 15 inside the lower housing 11. That is, the driven shaft 13 also has first and second journal portions 13a and 13b formed at two predetermined axial positions, and is similar to the balancer weight 16 of the drive shaft 12 between the journal portions 13a and 13b. A balancer weight 19 is provided integrally.

  As shown in FIGS. 1 and 5, each of the journal portions 13a and 13b has first and second driven side bearing portions 20a formed in a substantially half shape between the joint surfaces of the housings 10 and 11. , 20b, and is rotatably supported by first and second driven bearing members 21a, 21b configured in the same manner as the first and second driving bearing members 18a, 18b. Yes.

  Further, as shown in FIG. 5, the inner peripheral surfaces of the first and second drive side bearing portions 17a and 17b and the first and second driven side bearing portions 20a and 20b are respectively annular along the circumferential direction. A groove 22 is formed, and a series of oil passages 23 for introducing lubricating oil into the annular grooves 22 are formed in the joint surface of the lower housing 11 by notches.

  Further, in the first and second drive side bearing members 18a and 18b and the first and second driven side bearing members 21a and 21b, small-diameter oil holes 24 are provided along the radial direction in the vicinity of the intermediate positions in the circumferential direction. It is formed through. With this configuration, the lubricating oil introduced into the annular grooves 22 through the oil passages 23 passes through the oil holes 24 and the journal portions 12a, 12b in the bearing portions 17a, 17b, 20a, 20b. , 13a and 13b are lubricated.

  On the other hand, as shown in FIG. 1, the upper housing 10 is similar to the lower housing 11 side in the state where the housings 10 and 11 are joined to the first and second drive side bearing portions 17a and 17b. Each of the annular grooves 25 communicating with the annular groove 22 is formed with a cutout, and a small-diameter introduction hole 26 is formed at a substantially intermediate position in the circumferential direction of the annular groove 25 of the second drive side bearing portion 17b.

  Also, in the third drive side bearing portion 17c, a small-diameter introduction hole 27 as a lubricating oil supply portion is formed in the radial direction along the radial direction, and the introduction hole 27 and the second drive side bearing are provided. The introduction hole 26 of the portion 17 b communicates with an oil passage 28 formed in the upper housing 10.

  Further, the bearing members 18a, 18b, 21a, and 21b disposed on the upper housing 10 side are similar to the bearing members 18a, 18b, 21a, and 21b disposed on the lower housing 11 side. A small-diameter oil hole 29 is formed through.

  That is, from such a configuration, the lubricating oil introduced into the annular grooves 25 from the annular grooves 22 on the lower housing 11 side also passes through the oil holes 29 on the upper housing 10 side. The sliding of the journal portions 12a, 12b, 13a, 13b in 17a, 17b, 20a, 20b is lubricated.

  Further, the lubricating oil in the annular groove 25 of the second drive side bearing portion 17 b is guided to the third drive side bearing portion 17 c side through the oil passage 28, and the third drive is performed through the introduction hole 27. The sliding of the third journal portion 12c in the side bearing portion 17c is lubricated.

  Further, in the oil pan 4, a lubrication that injects the lubricating oil toward the open portion of the third drive side bearing portion 17 c of the drive shaft 12, that is, the outer peripheral portion of the lower half side of the third journal portion 12 c. An oil jet 30 that is an oil injection mechanism is provided. As a result, the lubricating oil is constantly supplied to the opened portion of the third journal portion 12c.

  From the above configuration, the basic operation of the balancer device 5 is the same as that of the prior art, so that the description thereof will be omitted. Hereinafter, only the characteristic operation of the balancer device 5 according to the present embodiment will be described with reference to FIG. 7 and FIG. 7, the balancer device 5 has a feature on the drive side, and therefore only the operation during rotation of the drive shaft 12 will be described. 6 shows a state where the drive shaft 12 is bent and deformed based on the structure of the present invention, and FIG. 7 shows a state where the drive shaft 12 is bent and deformed based on the conventional structure. Indicates the direction of the force acting on each part.

  In the balancer device 5, bending deformation that occurs near the position where the balancer weight 16 is disposed based on the centrifugal force of the balancer weight 16 when the drive shaft 12 rotates is passed through a clearance provided in the second drive side bearing portion 17 b. May extend to the other axial end, that is, the third journal portion 12c. The bending deformation changes depending on the bending rigidity of the drive shaft 12 and the arrangement interval of the journal portions 17a to 17c. Therefore, here, the drive shaft 12 is bent and deformed so as to wave. A case will be described as an example.

  In this case, as shown in FIG. 7, reaction forces f1 and f2 against the centrifugal force F act downward on the first and second drive-side bearing portions 17a and 17b, respectively, while the third drive-side bearing portion. A reaction force f3 against the elastic force F ′ generated on the other end side due to the bending deformation acts on 17c upward. And in the support structure based on a prior art, since each said bearing part 17a-17c supports the perimeter of each said journal part 12a-12c, in each said bearing part 17a-17c, all rotation is carried out. Friction forces based on the reaction forces f1 to f3 are generated over the circumferential area.

  As a result, since the frictional force based on the reaction forces f1 to f3 is added to the frictional force due to normal sliding on the bearings 17a to 17c, the bearings 17a to 17c are provided at all locations of the bearings 17a to 17c. Friction loss that occurs between the bearing portions 17a to 17c and the journal portions 12a to 12c increases.

  On the other hand, in the present embodiment, as shown in FIG. 6, in the first and second drive-side bearing portions 17a and 17b, the reaction force f1, which resists the centrifugal force F, as in the prior art. Although the frictional force based on f2 is generated over the entire circumference of the rotation, the third drive side bearing portion 17c is configured to support only the upper half portion of the third journal portion 12c and open the lower half portion. Therefore, the frictional force based on the reaction force f3 against the elastic force F ′ is generated only in the upper half rotation region in FIG. 6, and the lower half rotation region is based on the reaction force f3. Does not occur.

  That is, in the third drive side bearing portion 17c, although the elastic force F ′ is generated in the entire rotation area of the third journal portion 12c, the third drive side bearing portion is opened by opening the lower half portion of the third journal portion 12c. Since it is possible to reduce the sliding range of the third journal portion 12c at 17c, an increase in friction loss occurring between the both 12c and 17c is suppressed, thereby causing friction loss occurring between the both 12c and 17c. Can be reduced as compared with the prior art.

  Further, in this embodiment, only the upper half of the third journal portion 12c in FIG. 6 is supported by the third drive side bearing portion 17c, but the other end of the drive shaft 12 is the tension of the chain 7. Since it is always pulled upward by T, the third journal due to the elastic force F ′ in the unsupported region even if the lower half of the third journal portion 12c is not supported by the bearing portion as in the prior art. There is no possibility that the swinging of the portion 12c will increase.

  In other words, since the tension T of the chain 7 acts in a direction in which the third journal portion 12c is pressed against the third drive side bearing portion 17c, the axial center position of the third journal portion 12c is exerted by the tension T of the chain 7. It is possible to hold. Then, by utilizing this, the support load of the lower half side of the third journal portion 12c is secured by the tension T, so that the third journal portion 12c can be retained without sacrificing the holding performance. Friction loss that occurs between the portion 12c and the third drive side bearing portion 17c can be reduced.

  Furthermore, in the present embodiment, the elastic force F can be obtained by placing the support of the lower half of the third journal portion 12c borne by the lower housing 11 side in the structure according to the prior art on the tension T of the chain 7. It is possible to reduce the load that the third drive side bearing portion 17c receives from the third journal portion 12c based on ', and this occurs between the third journal portion 12c and the third drive side bearing portion 17c. It is also possible to reduce the friction itself.

  Therefore, according to this embodiment, by adopting a configuration in which only the upper half of the third journal portion 12c is supported and the lower half is opened in the third drive side bearing portion 17c, the centrifugal force of the balancer weight is adopted. Even if the entire drive shaft 12 is bent and deformed based on the above, the sliding range of the third journal portion 12c in the third drive-side bearing portion 17c is reduced without sacrificing the retaining property of the drive shaft 12, and the second By reducing the friction acting on the third drive side bearing portion 17c and a synergistic action, it is possible to effectively reduce the friction loss generated between the third journal portion 12c and the third drive side bearing portion 17c. it can. As a result, the fuel efficiency of the engine can be improved, and the wear resistance of the third journal portion 12c can be improved and the seizure can be prevented.

  Further, when the lower half portion of the third journal portion 12c is opened, when the lubricating oil staying in the oil pan 4 is scattered as the balancer weight rotates, the third journal portion 12c that has released the lubricating oil is released. The lower half of the third journal portion 12c can be used for lubrication.

  Moreover, by opening the lower half of the third journal portion 12c, the entire lower half of the third journal portion 12c can be immersed in the lubricating oil staying in the oil pan 4 when the engine is stopped. . As a result, even if the oil level of the lubricating oil drops after starting the engine, sufficient lubricating oil adheres to the lower half of the third journal portion 12c, so the engine speed is increased immediately after starting the engine. Even in this case, sufficient lubrication of the third journal portion 12c can be achieved.

  Further, by providing the oil jet 30 in the oil pan 4, it becomes possible to supply sufficient lubricating oil to the third journal portion 12c, and the third journal in the third drive side bearing portion 17c. The lubricity can be improved.

  In the third drive side bearing portion 17c, in addition to the supply of the lubricating oil from the lower half side as described above, the inner peripheral surface of the third drive side bearing portion 17c through the introduction hole 27. Since it is possible to introduce lubricating oil between the first journal portion 12c and the outer peripheral surface of the third journal portion 12c, the third journal portion 12c can be constantly lubricated stably.

  Further, by providing an endless transmission member for transmitting the rotational force of the crankshaft 3 at the other end of the drive shaft 12, the endless transmission member is arranged as far as possible from the axial direction position of the second journal portion 12b. Can be ensured as long as possible, so that the third journal portion 12c can be effectively supported, and as a result, the retainability of the third journal portion 12c can be improved.

  And since the said endless transmission member was comprised with the chain 7, strong tension | tensile_strength can be exhibited with respect to the drive shaft 12, and the retainability of the 3rd journal part 12c can be improved further.

  The present invention is not limited to the configuration of the above-described embodiment. For example, the quantity, size and shape of the balancer weights 16 and 19 can be freely changed according to the specifications and applications of the applied internal combustion engine. .

  Further, the balancer device 5 and the oil pan 4 are not limited to being configured integrally as in the above-described embodiment, and may be configured separately.

It is the sectional view on the AA line of FIG. It is a front view of a balancer apparatus. It is the BB sectional view taken on the line of FIG. It is a top view which shows a drive shaft and a driven shaft. It is a top view of a lower housing. It is a schematic diagram explaining the support structure of the drive shaft of the balancer apparatus which concerns on this invention. It is a schematic diagram explaining the support structure of the drive shaft in the conventional balancer apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Crankshaft 4 ... Oil pan 5 ... Balancer device 7 ... Chain 10 ... Upper housing (housing)
11 ... Lower housing (housing)
12 ... Drive shaft (balancer shaft)
13 ... Driven shaft (balancer shaft)
12a to 12c: first to third journal portions 13a, 13b: first and second journal portions 16: balancer weights 17a to 17c: first to third drive side bearing portions (bearing portions)
19 ... Balancer Weight

Claims (9)

A drive rotator in which the rotational force of the crankshaft is transmitted through an endless transmission member;
A balancer shaft having a balancer weight that rotates integrally with the drive rotor and cancels vibrations of the internal combustion engine;
A housing having a plurality of bearing portions that rotatably support the balancer shaft at a plurality of locations,
A balancer device for an internal combustion engine, wherein a bearing portion adjacent to the drive rotor among the plurality of bearing portions is open on a side opposite to a direction pulled by a tension of the endless transmission member. The balancer device for an internal combustion engine according to claim 1, wherein the drive rotor is disposed at one axial end of the balancer shaft. The balancer device for an internal combustion engine according to claim 1, wherein the endless transmission member is a chain. The bearing portion adjacent to the drive rotating body is provided with a lubricating oil supply portion that supplies lubricating oil to a region on the balancer shaft that is pulled by the tension of the endless transmission member. The balancer device for an internal combustion engine according to claim 1. 2. The internal combustion engine according to claim 1, further comprising: a lubricating oil injection mechanism that supplies lubricating oil to a portion of the balancer shaft that is opened in a bearing portion adjacent to the drive rotating body. Balancer device. The housing is disposed in an oil pan of an internal combustion engine;
The balancer device for an internal combustion engine according to claim 1, wherein the bearing portion adjacent to the drive rotating body is opened in a direction in which the lubricating oil stays. 7. The internal combustion engine according to claim 6, wherein a portion of the balancer shaft that is opened in a bearing portion adjacent to the drive rotating body is immersed in lubricating oil at least when the internal combustion engine is stopped. Balancer device. A drive rotator in which the rotational force of the crankshaft is transmitted through an endless transmission member;
A balancer shaft having a balancer weight that rotates integrally with the drive rotor and cancels vibrations of the internal combustion engine;
A housing having a plurality of bearing portions that rotatably support the balancer shaft at a plurality of locations,
Of the plurality of bearing portions, a bearing portion provided adjacent to the drive rotating body is formed in an arc shape so as to support only a direction side in which the crankshaft is disposed. Balancer device. A drive rotator in which the rotational force of the crankshaft is transmitted through an endless transmission member;
A balancer shaft having a balancer weight that rotates integrally with the drive rotor and cancels vibrations of the internal combustion engine;
A housing having a plurality of bearing portions that rotatably support the balancer shaft at a plurality of locations,
A balancer device for an internal combustion engine, wherein a bearing portion adjacent to the drive rotor is formed in a substantially semicircular shape, and the balancer shaft is pressed by the tension of the endless transmission member.

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