JP2900630B2 - Balancer bearing structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure of a balancer used for damping engine vibration.

[0002]

2. Description of the Related Art Conventionally, as a balancer for eliminating inertial force and inertial couple by an engine piston, a connecting rod and the like to attenuate the vibration of the engine, for example, US Pat.
There is one disclosed in Japanese Patent No. As shown in FIG. 8, the balancer device includes a fixed shaft 32 that is non-rotatably provided on a housing 31, an unbalance mass 34 that is loosely fitted on the outer periphery of the fixed shaft 32, And a bearing 35 interposed between the balance mass 34 and the support hole 33. The bearing 35 is fixed to a support hole 33, and the bearing 35 and the unbalance mass 34 are supported so as to be able to rotate integrally with the fixed shaft 32. Then, the rotation of the crankshaft 36 is transmitted to the unbalance mass 34 via the gears 37 and 38 and is rotated to attenuate engine vibration.

[0003]

However, when a wound bearing is used as the bearing 35 in the conventional balancer, the following problem occurs. Here, the wound bearing is a cylindrical bearing formed by winding a plate-shaped material and abutting both end edges thereof, and the abutting portion is a joint.
As described above, since the wound bearing is not endless but has a seam, depending on the manner in which the wound bearing is attached to the support hole 33 of the unbalance mass 34, the fixed shaft 32 may be damaged by contact with the seam. there were.

The present invention has been made in view of the above circumstances, and has as its object to prevent a fixed shaft from being damaged at a joint portion and to improve the durability of the fixed shaft. Another object of the present invention is to provide a bearing structure.

[0005]

In order to achieve the above object, the present invention provides a fixed shaft, which is loosely fitted on an outer periphery of the fixed shaft,
A vibration damping unbalance mass having a mass portion formed at an eccentric position centered on the fixed shaft; and a bearing interposed between the fixed shaft and a support hole of the unbalance mass. In a bearing structure of a balancer in which a balance mass is supported so as to be integrally rotatable with respect to a fixed shaft, the bearing is constituted by a winding bearing in which a plate material is wound in a cylindrical shape, and both ends of the plate material are opposed to each other. The joints of the wound bearings are arranged on the mass side of the support hole in the unbalance mass.

[0006]

When the unbalanced mass loosely fitted on the outer periphery of the fixed shaft rotates about the fixed shaft, a load is applied to the bearing toward the mass due to the centrifugal force of the mass of the unbalanced mass. This load creates a gap between the bearing and the fixed shaft,
It acts to make it wider on the mass part side and make it narrower on the opposite mass part side. In the present invention, a wound bearing having a joint is used as the bearing, but since the joint is located on the mass side of the support hole, the joint presses the fixed shaft by the load. There is no.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG. FIG. 2 is a front view of the balancer 1 disposed below a crankshaft (not shown) of the engine, and FIG. 3 is a plan view of the balancer 1. The balancer 1 includes a housing 2, first and second fixed shafts 3 and 4, and first and second unbalance masses 5 and 6. The housing 2 has a substantially rectangular frame shape having a pair of front and rear support pieces 7 and 8, and first and second fixed shafts 3 and 4 are provided between the two support pieces 7 and 8. That is, holes 7a, 8a are penetrated through the support pieces 7, 8, and both ends of the first and second fixed shafts 3, 4 are press-fitted into these holes 7a, 8a. As a result, the first and second fixed shafts 3 and 4 cannot rotate with respect to the housing 2.

A first unbalance mass 5 is provided on the outer periphery of the first fixed shaft 3. As shown in FIGS. 1 and 3, the first unbalance mass 5 includes a bearing 5a having a support hole 9 and a semi-columnar mass 5b formed on the outer periphery of the bearing 5a. ing. Therefore, the mass portion 5 b is eccentric with respect to the first fixed shaft 3. A cylindrical bearing 14 is fixed in the bearing portion 5a, and the bearing 14 and the first unbalance mass 5 are supported by the first fixed shaft 3 so as to be integrally rotatable. Similarly, on the outer periphery of the second fixed shaft 4, a second unbalanced mass 6 composed of a bearing portion having a support hole 10 and a mass portion 6 b is rotatably supported by a bearing 14.

In order to transmit the rotation of the crankshaft to the first and second unbalance masses 5 and 6, the crankshaft is provided with a drive comprising a helical gear as shown by a two-dot chain line in FIG. A gear 11 is mounted.
Also, the rear part of the first unbalance mass 5 (the upper part of FIG. 3)
A first driven gear 12 is mounted on the outer circumference, and a second driven gear 13 is mounted on the rear outer circumference of the second unbalance mass 6. A first driven gear 12 meshes with the driving gear 11, and a second driven gear 13 meshes with the first driven gear 12.

Therefore, when the crankshaft rotates, the rotation is transmitted to the first unbalance mass 5 via the drive gear 11 and the first driven gear 12. As a result, the first unbalance mass 5 rotates in the direction opposite to the rotation direction of the crankshaft. The rotation of the first unbalanced mass 5 is transmitted to the second unbalanced mass 6 via the second driven gear 13, and the unbalanced mass 6 is opposite to the first unbalanced mass 5. Direction (the same rotation direction as the crankshaft). The rotation of the unbalance masses 5 and 6 generates a load in a direction of eliminating inertial force and inertial couple by the piston, the connecting rod, and the like, and the load reduces vibration of the crankshaft.

The bearings 14 mounted in the support holes 9 and 10 of the first and second unbalance masses 5 and 6, respectively.
In this embodiment, a cylindrical wound bearing is used. The wound bearing is a flat bearing material 1 as shown in FIG.
5 is wound as shown by a two-dot chain line, and formed by bringing both end edges 15a and 15b of the bearing material 15 into contact with each other. As shown in FIG. 1, in the first unbalanced mass 5, the bearings 14 are arranged such that the joints 16, which are the contact portions of the both end edges 15 a and 15 b, are located on the mass portion 5 b side of the support hole 9. It is press-fitted into the support hole 9.

Further, both ends of one surface (upper surface in FIG. 6) of the bearing material 15 which is an inner peripheral surface of the bearing 14 are chamfered obliquely. Therefore, when the first unbalance mass 5 is loosely fitted on the outer periphery of the first fixed shaft 3, there is a gap between the joint 16 of the bearing 14 and the outer periphery of the first fixed shaft 3 as shown in FIG. As shown in FIG. 5, a gap G having a substantially triangular cross section extending in parallel with the axis L of the first fixed shaft 3.
Occurs. This gap G functions as an oil reservoir. In the same manner as described above, the bearing 14 is press-fitted into the support hole 10 so that the joint 16 is located on the side of the mass portion 6b of the support hole 10 in the second unbalanced mass 6 as well.

An annular groove 17 is formed on the outer periphery of the fixed shaft 3 in order to supply a part of the engine oil to the gap G and form an oil film on a sliding contact portion between the first fixed shaft 3 and the bearing 14. Is formed. In the first fixed shaft 3, an oil passage 18 extending in the direction of the axis L, a communication passage 19 for communicating the oil passage 18 with the annular groove 17, and the like are formed.
Then, the engine oil guided to the housing 2 is supplied to the gap G through the oil passage 18, the communication passage 19, the annular groove 17, and the like. Although not shown, the second fixed shaft 4 also has the same annular groove, oil passage, communication passage, and the like as described above.

Next, the operation and effect of the embodiment constructed as described above will be described. As the crankshaft rotates, the first and second unbalanced masses 5, 6
Is rotated about the first and second fixed shafts 3 and 4, since the mass portions 5b and 6b are eccentric with respect to the fixed shafts 3 and 4, the mass portions 5b and 6b A centrifugal force acts as shown by an arrow in FIG. Due to this centrifugal force, the mass portions 5b,
A load acting on the 6b side acts. This load is applied to the bearing 14
The gap between the shaft and each of the fixed shafts 3 and 4 is increased on the side of the mass portions 5b and 6b (A portion in FIG. 1), and is increased on the side opposite to the mass portion (B in FIG. 1).
In part (2), it acts to make it narrow. For this reason,
In the balancer 1 using the bearing 14 composed of a wound bearing, if the joint 16 is located at the portion B, the fixed shafts 3 and 4 may be damaged by the corner of the joint 16, whereas in this embodiment In this case, since the joint 16 is located at the portion A, the joint 16 does not damage the fixed shafts 3 and 4 by pressing the fixed shafts 3 and 4. Thereby, the durability of the fixed shafts 3 and 4 is improved.

Further, in this embodiment, an annular groove 17 is formed on the outer periphery of the first and second fixed shafts 3 and 4, and an oil sump is provided between the joint 16 and the outer periphery of the fixed shafts 3 and 4. , The fixed shafts 3 and 4 and the bearing 1
4, the engine oil is always supplied, and an oil film can be reliably formed. Further, engine oil can be supplied to the thrust portion. Thereby, seizure in the bearing 14 due to the oil film shortage can be prevented.

Also, since a sufficient oil film can be secured,
By reducing the diameters of the first and second fixed shafts 3, 4, the first and second unbalance masses 5, 6 can be reduced in weight. In other words, as a means for preventing the oil film from running out in the bearing 14, it is common to increase the diameter of the fixed shaft to reduce the surface pressure between the fixed shaft and the bearing. Each fixed shaft 3, 4
It is possible to increase the unbalance amount, reduce the weight of the unbalance masses 5 and 6, reduce friction, and the like by reducing the diameter of the unbalance.

Also, in the unlikely event that a gap is formed in the joint 16 of the bearing 14 due to the friction caused by the rotation of the first and second unbalanced masses 5 and 6, the gap becomes a step.
Since the seam 16 is chamfered, the first and second fixed shafts 3 and 4 are not damaged by the chamfer. For this reason, it is not necessary to form the seam 16 into a clinch shape (a shape that fits in an uneven relationship) or the like and join them.

It should be noted that the present invention is not limited to the configuration of the above embodiment, and may be arbitrarily changed without departing from the spirit of the present invention, for example, as follows. (1) In the above embodiment, in order to supply the engine oil to the gap G, the annular grooves 1 are formed around the outer circumferences of the first and second fixed shafts 3 and 4.
7, the groove 2 extending in the longitudinal direction is formed on one surface of the bearing material 15 as shown in FIG.
0 may be formed. (2) Joint 16 of bearing 14 in support holes 9 and 10
The position A is optimal in FIG. 1, but may be slightly deviated from this position. (3) In the above-described embodiment, the gap G for the oil reservoir is formed to have a substantially triangular cross section. However, the gap G may be appropriately changed to a trapezoidal cross section, a rectangular cross section, or an elliptical cross section. Further, the gap G may be omitted. (4) The joint 16 of the wound bearing may not be parallel to the axis L. (5) The present invention can also be applied to a balancer using one unbalanced mass or three or more unbalanced masses.

[0019]

As described in detail above, according to the present invention, a wound bearing is used as a bearing interposed between the unbalanced mass and the fixed shaft, and the joint of the wound bearing is supported by the unbalanced mass. Since it is arranged on the side of the mass portion of the hole, it is possible to prevent the fixed shaft from being damaged by the joint portion and to achieve an excellent effect that the durability of the fixed shaft can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a first unbalance mass according to an embodiment of the present invention.

FIG. 2 is a front view of a balancer in one embodiment.

FIG. 3 is a plan view of a balancer according to one embodiment.

FIG. 4 is an enlarged view showing a portion A in FIG. 1;

FIG. 5 is a side sectional view of a first fixed shaft in one embodiment.

FIG. 6 is a perspective view of a state in which the wound bearing in one embodiment is expanded.

FIG. 7 is a perspective view of a state in which another example of a wound bearing provided with a groove is developed.

FIG. 8 is a sectional view of a conventional balancer.

[Explanation of symbols]

Reference numeral 3 denotes a first fixed shaft, 4 denotes a second fixed shaft, 5 denotes a first unbalanced mass, 5b, 6b denotes a mass portion, 6 denotes a second unbalanced mass, 9, 10 denotes a support hole, and 14 denotes a hole. Bearing, 15: Bearing material, 15a, 15b: Edge, 16: Joint

Claims (1)

(57) [Claims] 1. A fixed shaft, an unbalanced mass for vibration damping, which is loosely fitted to an outer periphery of the fixed shaft and has a mass portion formed at an eccentric position about the fixed shaft, and an unbalanced mass for the fixed shaft. And a bearing interposed between the support holes of the
In the bearing structure of a balancer in which the bearing and the unbalance mass are supported so as to be integrally rotatable with respect to a fixed shaft, the bearing is configured by a winding bearing in which a plate material is wound in a cylindrical shape, and both ends of the plate material are A bearing structure for a balancer, wherein a seam of a wound bearing whose edges are opposed to each other is arranged on the mass portion side of the support hole in the unbalance mass.