JP6271669B2 - Balancer device for internal combustion engine - Google Patents

Description

  The present invention relates to a balancer device that is provided in an internal combustion engine and reduces vibration caused by rotation of the internal combustion engine.

  In the balancer device, rotation is transmitted from a crank gear provided on the crankshaft to the balancer shaft via a driven gear. However, since the crankshaft and the balancer device are supported by separate structures, there is a problem that an error is likely to occur in the supported position and a rattling sound is generated.

  In order to solve such a problem, Patent Document 1 discloses a method of absorbing backlash by using a scissors gear as a driven gear to reduce rattling noise.

JP 2007-239521 A

  However, since Patent Document 1 uses an expensive scissor gear as compared with a normal gear, the cost of the balancer device has increased. Further, when the scissors gear is used, the operation of meshing the gears is complicated.

  The objective of this invention is providing the balancer apparatus of the internal combustion engine which can reduce a rattling noise, without using a scissors gear.

  The present invention has been devised in view of the above-described conventional problems, and annular grooves having different diameters are provided on both side surfaces in the axial direction of the drive gear in the balancer device, and each annular groove is axially provided. It is characterized by being formed up to the overlapping depth.

  According to the present invention, rattling noise can be reduced without using a scissor gear.

It is a front view of a balancer apparatus. It is the same apparatus YY direction sectional drawing. It is the figure which removed the lower housing and looked at the housing apparatus from the bottom. It is the schematic which shows the deformation | transformation of a balancer drive shaft and a balancer drive gear. FIG. 6 is a cross-sectional view of a main gear according to a second embodiment. FIG. 6 is a cross-sectional view of a main gear according to a third embodiment. FIG. 6 is a cross-sectional view of a main gear according to a fourth embodiment. FIG. 10 is a cross-sectional view of a main gear according to a fifth embodiment. FIG. 10 is a cross-sectional view of a main gear according to a sixth embodiment. FIG. 10 is a cross-sectional view of a main gear according to a seventh embodiment. FIG. 10 is a cross-sectional view of a main gear according to an eighth embodiment.

  Embodiments 1 to 8 of the balancer device according to the present invention will be described below in detail with reference to FIGS.

[Embodiment 1]
1 is a front view of the balancer device mounted on the engine, FIG. 2 is a cross-sectional view in the YY direction of FIG. 1, and FIG. 3 is a view of the housing device viewed from the bottom with the lower housing removed.

  As shown in FIG. 1, a balancer device 1 that is rotationally driven by a crank gear 3 fixed to a crankshaft 2 is provided on the lower surface of a cylinder block (not shown) of an internal combustion engine.

  As shown in FIGS. 1 to 3, the balancer device 1 meshes with a crank gear (input gear) 3, a main gear (drive gear) 5 to which the rotational force from the crank gear 3 is transmitted, and a rotational force from the main gear 5. The balancer drive shaft 4 to be transmitted, the balancer drive gear 7 fixed to the balancer drive shaft 4, the balancer driven gear 8 in which the teeth of the balancer drive gear 7 mesh with each other, and the rotational force from the balancer driven gear 8 are transmitted. The balancer driven shaft 6 is provided.

  The balancer drive shaft 4 and the balancer driven shaft 6 are integrally formed with semicircular balancer weights 4a and 6a, respectively. The balancer drive shaft 4 and the balancer driven shaft 6 are arranged in parallel to the longitudinal direction of the internal combustion engine. Both shafts 4 and 6 are designed to rotate twice when the crankshaft 2 rotates once.

  The balancer drive shaft 4 and the balancer driven shaft 6 are rotatably supported by a lower housing 10 and an upper housing 11 via a slide bearing 9. The lower housing 10 and the upper housing 11 are fastened to each other by bolts 12.

  The crank gear 3, the main gear 5, the balancer drive gear 7, and the balancer driven gear 8 have a disk shape, and through-holes are formed through which the crankshaft 2, the balancer drive shaft 4, and the balancer driven shaft 6 are inserted, respectively. Yes. Each of the gears 3, 5, 7, and 8 is integrally formed with a plurality of helical teeth having a predetermined angle on the outer periphery and a twist angle in the axial direction.

  In the balancer device 1, when the crankshaft 2 rotates, the crank gear 3 fixed to the crankshaft 2 rotates in synchronization with the rotation. At this time, the rotational driving force is transmitted from the crank gear 3 to the main gear 5 fixed to the balancer drive shaft 4, and the balancer drive shaft 4, the balancer drive gear 7, the balancer driven gear 8, and the balancer weight 6a having the balancer weight 4a. The held balancer driven shaft 6 is rotated.

  The balancer device 1 generates an excitation force having a phase opposite to the engine excitation force secondary component by the balancer drive shaft 4 and the balancer driven shaft 6 that rotate at twice the speed of the engine having the balancer weights 4a and 6a. The vibration is offset.

  Here, as shown in FIG. 2, the balancer device 1 is provided with annular grooves 5 a and 5 b having different diameters on both side surfaces in the axial direction with respect to the main gear 5 meshing with the crank gear 3. The annular grooves 5a and 5b are formed to a depth overlapping in the axial direction.

  Normally, in the balancer device, collision vibration is generated between the crank gear 3 and the main gear 5 due to the rotational fluctuation of the crankshaft 2.

  Further, since the balancer drive shaft 4 is provided with the balancer weight 4a, the shaft itself rotates while deforming into a bow shape. For this reason, the main gear 5 fixed to the balancer drive shaft 4 may also be inclined. Furthermore, since the crankshaft 2 is supported by a separate structure from the balancer device 1, a positional shift occurs between the crank gear 3 fixed to the crankshaft 2 and the main gear 5. For this reason, rattling noise is likely to occur at the meshing portion between the crank gear 3 and the main gear 5.

  The vibration caused by the rotational fluctuation and the rattling noise is transmitted to the lower housing 10 and the upper housing 11 through the main gear 5, the balancer drive shaft 4, and the sliding bearing 9, and generates abnormal noise.

  However, in the balancer device 1 according to the first embodiment, since the above-described annular grooves 5a and 5b are formed in the main gear 5, vibrations generated between the crank gear 3 and the main gear 5 are absorbed by the annular grooves 5a and 5b. As a result, it is possible to suppress the transmission of vibration from the tooth surface to the inner peripheral side in the main gear 5 and improve the sound vibration performance.

  Even if the balancer drive shaft 4 is deformed by the balancer weight 4a, the main gear 5 is formed with the annular grooves 5a and 5b. Adapted to. As a result, in the first embodiment, it is possible to obtain an operational effect that the rattling noise can be suppressed as much as possible.

  From the above, in the first embodiment, since the scissors gear is not used for improving the sound vibration performance as in the prior art, it is possible to reduce the cost and simplify the assembling work.

  Further, since the annular grooves 5 a and 5 b overlap in the axial direction in the main gear 5, at least one of the annular grooves 5 a and 5 b is formed in all the axial directions of the main gear 5. As a result, vibration transmission from the tooth surface to the inner peripheral direction in the main gear 5 can be further suppressed.

  In addition, since the annular grooves 5a and 5b overlap in the axial direction in the main gear 5, the rigidity of the main gear 5 is further lowered and is easily bent, and the contact area with the helical teeth in the crank gear 3 on the other side is increased. Thus, it is possible to easily engage with each other and to suppress rattling noise.

  Further, when the scissor gear is used, the rattling noise can be reduced, but the friction between the gears is increased and the meshing noise is increased. That is, conventionally, whether to suppress the rattling sound or the meshing sound is a trade-off state, and it is impossible to suppress both the rattling sound and the meshing sound at the same time. On the other hand, in the first embodiment, the vibration transmitted from the tooth surface to the inner peripheral surface of the main gear 5 can be blocked by the overlapping annular grooves 5a and 5b. Both of them can be blocked.

  FIG. 2 shows the case where the small-diameter annular groove 5b is formed on the axial balancer weight 4a side and the large-diameter annular groove 5a is formed on the axial balancer drive gear 7 side. A large-diameter annular groove 5a on the direction balancer drive gear 7 side may be formed on the axial balancer weight 4a side. Hereinafter, each effect will be described.

  FIG. 4 is a schematic view showing a modification of the balancer drive shaft and the balancer drive gear in the first embodiment. 4 (a) and 4 (b), a small-diameter annular groove 5b is formed on the axial balancer weight 4a side, and a large-diameter annular groove 5a is formed on the axial balancer drive gear 7 side. d) shows a case where the large-diameter annular groove 5a is formed on the axial balancer weight 4a side and the small-diameter annular groove 5b is formed on the axial balancer drive gear 7 side.

  Since the balancer drive shaft 4 is formed with a balancer weight 4a, the shaft 4 itself rotates while deforming into an arcuate shape. FIG. 4A shows a case where the axial center portion where the balancer weight 4a is formed is deformed downward, and both axial ends are deformed upward. FIG. 4B shows a case where the axial center portion where the balancer weight 4a is formed is deformed to the upper side and both axial ends are deformed to the lower side.

  In FIG. 4A, both ends of the balancer drive shaft 4 in the axial direction are deformed upward, so that the outer periphery of the main gear 5 is close to the crank gear 3. On the other hand, in FIG. 4B, both ends of the balancer drive shaft 4 in the axial direction are deformed downward, so that the outer periphery of the main gear 5 is away from the crank gear 3. In particular, the axial balancer drive gear 7 side of the outer periphery of the main gear 5 moves away from the crank gear 3.

  In such a case, since the main gear 5 moves away from the crank gear 3 in the case of FIG. 4B than in the case of FIG. 4A, the backlash increases, and the rattling noise increases accordingly. Become. Therefore, in order to reduce the rattling noise, it is necessary to reduce the backlash on the balancer drive gear 7 side of the outer periphery of the main gear 5 at the time of FIG.

  As described above, in the case of FIGS. 4A and 4B, since the small-diameter annular groove 5b is formed on the balancer weight 4a side, the outer peripheral side of the main gear 5 is easily deformed to the balancer weight 4a side. When the outer peripheral side of the main gear 5 is deformed to the balancer weight 4a side, the balancer drive gear 7 side of the outer periphery of the main gear 5 approaches the crank gear 3 side. Therefore, when the small-diameter annular groove 5b is formed on the axial balancer weight 4a side, the backlash on the balancer drive gear 7 side between the main gear 5 and the crank gear 3 can be absorbed, and the rattling noise is further increased. It becomes possible to suppress.

  On the other hand, FIG. 4 (c) shows a case where the central portion in the axial direction where the balancer weight 4a is formed is deformed downward, and both ends in the axial direction are deformed upward, and FIG. 4 (d) is the case where the balancer weight 4a is formed. The case where the axial direction center part deform | transforms into an upper side and the axial direction both ends is shown below.

  In FIG. 4C, both ends of the balancer drive shaft 4 in the axial direction are deformed upward, so that the outer periphery of the main gear 5 is close to the crank gear 3. In particular, the balancer drive gear 7 side on the outer periphery of the main gear 5 is close to the crankshaft 3. On the other hand, in FIG. 4D, both ends of the balancer drive shaft 4 in the axial direction are deformed downward, so that the outer periphery of the main gear 5 is moved away from the crank gear 3.

  In such a case, since the main gear 5 is closer to the crank gear 3 in the case of FIG. 4C than in the case of FIG. 4D, the friction is increased and the meshing noise is increased. Therefore, in order to reduce the meshing noise, it is necessary to reduce the friction between the main gear 5 on the balancer drive gear 7 side and the crank gear 3 at the time of FIG.

  As described above, in the case of FIGS. 4C and 4D, since the small-diameter annular groove 5b is formed on the balance drive gear 7 side, the outer peripheral side of the main gear 5 is easily deformed to the balancer drive gear 7 side. . When the outer peripheral side of the main gear 5 is deformed to the balancer drive gear 7 side, the balancer drive gear 7 side of the outer periphery of the main gear 5 is moved away from the crank gear 3 side. Therefore, when the small-diameter annular groove 5b is formed on the balancer drive shaft 7 side, the friction on the balancer drive gear 7 side between the main gear 5 and the crank gear 3 can be reduced, and the meshing noise is further suppressed. Is possible.

[Embodiment 2]
FIG. 5 is a cross-sectional view showing the main gear 5 of the balancer device according to the second embodiment. Hereinafter, the second and subsequent embodiments are the same as those of the first embodiment except for the annular grooves 5a and 5b of the main gear 5, and thus the description thereof is omitted.

  As shown in FIG. 5, in the second embodiment, the elastic body 13 having substantially the same shape as the annular grooves 5a and 5b has a pressing force on the inner and outer circumferences of the annular grooves 5a and 5b. Has been inserted. The elastic body 13 is made of rubber, resin, or damping steel material that absorbs vibration.

  According to the balancer device in the second embodiment, compared with the first embodiment, the elastic body 13 absorbs the vibration that is a sound generation source and suppresses the propagation of the vibration. It is possible to improve.

[Embodiment 3]
FIG. 6 is a cross-sectional view showing the main gear 5 of the balancer device according to the third embodiment. As shown in FIG. 6, in the third embodiment, instead of the elastic body 13 in the second embodiment, an inexpensive O-ring 14 as a vibration absorbing material has a pressing force on the inner and outer peripheries in the annular grooves 5a and 5b. Has been inserted.

  According to the balancer device in the third embodiment, as in the second embodiment, the O-ring 14 absorbs the vibration that is the source of the sound and suppresses the propagation of the vibration, thereby further improving the sound vibration performance. I can plan. Further, the use of an inexpensive O-ring as the vibration absorber can reduce the cost.

[Embodiment 4]
FIG. 7 is a cross-sectional view showing the main gear 5 of the balancer device according to the fourth embodiment. As shown in FIG. 7, in the fourth embodiment, the annular grooves 5a and 5b are formed with a step 5c so that the width of the opening is narrower than the bottom.

  When the elastic body 13 or the O-ring 14 is inserted into the annular grooves 5a and 5b, the elastic body 13 or the O-ring 14 is compressed by the opening when passing through the narrow opening, and reaches the bottom that is wider than the opening. When it reaches, it is released from the compression and returns to the optimal compression shape.

  Therefore, according to the balancer device in the fourth embodiment, in addition to the functions and effects of the second and third embodiments, it is possible to suppress the elastic body 13 or the O-ring 14 from dropping from the annular grooves 5a and 5b.

[Embodiment 5]
FIG. 8 is a cross-sectional view showing the main gear 5 of the balancer device according to the fifth embodiment. As shown in FIG. 8, in the fifth embodiment, in the aforementioned annular grooves 5a and 5b, at least one of the inner and outer peripheral surfaces from the bottom to the opening so that the opening width W2 becomes narrower than the bottom width W1. Is formed in a tapered shape. Since the opening width W2 is narrowly formed, it is possible to suppress the elastic body 13 or the O-ring 14 from dropping from the annular grooves 5a and 5b as in the fourth embodiment.

  Further, according to the balancer device in the fifth embodiment, it is easier to form the tapered grooves than in the case where the step 5c of the fourth embodiment is formed. Therefore, the annular grooves 5a and 5b can be easily formed. Become.

[Embodiment 6]
FIG. 9 is a cross-sectional view showing the main gear 5 of the balancer device according to the sixth embodiment. As shown in FIG. 9, in the sixth embodiment, both the inner and outer peripheral surfaces of the annular grooves 5a and 5b are tapered from the bottom to the opening so that the opening width W2 becomes narrower than the bottom width W1. Is formed.

  According to the balancer device in the sixth embodiment, the same operational effects as in the fifth embodiment are obtained.

[Embodiment 7]
FIG. 10 is a cross-sectional view showing the main gear 5 of the balancer device according to the seventh embodiment. As shown in FIG. 10, in the seventh embodiment, the above-described annular grooves 5a and 5b are formed so that the bottoms are positioned on the outer peripheral side of the main gear 5 with respect to the opening.

  According to the balancer device in the seventh embodiment, the centrifugal force acts on the elastic body 13 or the O-ring 14 toward the outer peripheral side of the main gear 5 by the rotation of the main gear 5. Thereby, the elastic body 13 or the O-ring 14 is pressed against the bottoms of the annular grooves 5a and 5b. As a result, it is possible to suppress the elastic body 13 or the O-ring 14 from dropping from the annular grooves 5a and 5b without performing expensive special processing as in the fifth and sixth embodiments.

[Embodiment 8]
FIG. 11 is a cross-sectional view showing the main gear 5 of the balancer device according to the eighth embodiment. As shown in FIG. 11, in Embodiment 8, a groove 15 having a larger diameter than the outer periphery of the annular grooves 5a and 5b is formed in the annular grooves 5a and 5b.

  According to the balancer device in the eighth embodiment, the elastic body 13 or the O-ring 14 drops from the annular grooves 5a and 5b when a part of the elastic body 13 or the O-ring 14 bites into the groove 15 due to the pressing force. Can be suppressed.

  Even if the groove 15 is provided on the smaller diameter side than the annular grooves 5a and 5b, the same effect can be obtained.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

  For example, in the above-described first to eighth embodiments, the configuration in which the annular grooves 5 a and 5 b are formed in the main gear 5 has been described. However, the annular groove is formed not only in the main gear 5 but also in the balancer driving gear 7 or the balancer driven gear 8. Is also possible. As a result, the sound vibration performance effect between the balancer drive gear 7 and the balancer driven gear 8 can be improved.

  As described above, as a balancer device for an internal combustion engine based on the above-described embodiment, for example, the following modes can be considered.

  In one aspect of the balancer device for an internal combustion engine, an elastic body is provided in the annular groove.

  Thereby, it becomes possible to aim at the further improvement of sound vibration performance by absorbing the vibration which becomes a sound generation source, and suppressing propagation of vibration.

  In a preferred aspect of the balancer device for the internal combustion engine, the elastic body is a rubber material.

  As a result, the elastic body, which is a rubber material, absorbs the vibration that is the source of the sound and suppresses the propagation of the vibration, thereby further improving the sound vibration performance.

  In still another preferred aspect, in the balancer device for an internal combustion engine, the elastic body is an O-ring.

  Thereby, it becomes possible to aim at cost reduction by using an O-ring for an elastic body.

  In still another preferred embodiment, in the balancer device for an internal combustion engine, the annular groove is formed such that the width of the opening is narrower than the bottom.

  Thereby, it is possible to suppress the elastic body or the O-ring from dropping from the annular groove due to the narrow opening.

  In a preferred aspect of the balancer device, the annular groove is formed in a tapered shape so that the width becomes narrower from the bottom toward the opening.

  This makes it easier to form the annular groove because it is easier to form a step as compared with the case where the step is formed.

  In another preferred embodiment, in the balancer device for an internal combustion engine, the annular groove has a bottom portion located on the outer peripheral side of the main gear with respect to the opening.

  Accordingly, it is possible to suppress the elastic body or the O-ring from dropping from the annular groove by centrifugal force without performing expensive special processing.

  In another preferred aspect, in the balancer device for an internal combustion engine, a groove having a larger diameter than the outer periphery of the annular groove or a smaller diameter than the annular groove is provided in the annular groove.

  Accordingly, it is possible to suppress the elastic body or the O-ring from dropping from the annular groove when a part of the elastic body or the O-ring bites into the groove due to the pressing force.

  In another preferred aspect, in the balancer device for an internal combustion engine, the axial balancer weight side of the drive gear is provided with an annular groove having a larger diameter than the opposite side.

  Thereby, the outer peripheral side of the drive gear is easily deformed to the side opposite to the axial balancer weight, and the meshing noise can be further suppressed.

  In another preferred aspect, in the balancer device of the internal combustion engine, an annular groove having a smaller diameter is provided on the axial balancer weight side of the drive gear than on the opposite side.

  As a result, the outer peripheral side of the drive gear is easily deformed to the axial balancer weight side, and the rattling noise can be further suppressed.

DESCRIPTION OF SYMBOLS 1 ... Balancer apparatus 2 ... Crankshaft 3 ... Crank gear (input gear)
4 ... Balancer drive shaft 4a ... Drive shaft side balance weight 5 ... Main gear (drive gear)
5a, 5b ... annular groove 6 ... balancer driven shaft 6a ... driven shaft side balance weight 7 ... balancer drive gear 8 ... balancer driven gear

Claims (5)

A balancer device for an internal combustion engine,
A balancer shaft with a balancer weight;
A driving gear that rotates integrally with the balancer shaft, and that receives a rotational force via an input gear from the crankshaft;
Annular grooves provided on both side surfaces of the drive gear, formed to a depth overlapping with each other in the axial direction, and having different diameters;
With
A balancer device for an internal combustion engine, wherein an annular groove formed on a side surface of the drive gear on a balancer weight side of the annular groove has a smaller diameter than an annular groove formed on an opposite side surface. The balancer device for an internal combustion engine according to claim 1 , wherein an elastic body is provided in the annular groove. 3. The balancer device for an internal combustion engine according to claim 2 , wherein the elastic body is a rubber material. The balancer device for an internal combustion engine according to claim 2 , wherein the elastic body is an O-ring. The balancer device for an internal combustion engine according to claim 2 , wherein the elastic body is a resin.

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