JPH0650136B2 - Torsional vibration prevention damper - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a torsional vibration preventing damper which is attached to a free end of a crankshaft or the like of a diesel engine and prevents torsional vibration occurring in the shaft.

<Prior Art> In recent years, the crankshaft resonates at a specific engine speed due to the increase in the number of cylinders and the increase in speed and output of small and medium-sized diesel engines, and remarkable torsional vibrations frequently occur. And
In order to prevent this torsional vibration, a so-called tune damper is conventionally used, for example. This tune damper has a spline groove on the outer circumference of an inner ring fixed to the free end of the crankshaft, while an intermediate piece and a leaf spring are alternately arranged radially on the inner circumference of the outer ring that is fixed to the rotating wheel and fitted onto the inner ring. The tip of the leaf spring is fitted in the spline groove, and the gap between the leaf spring and the intermediate piece is filled with lubricating oil. The torsional vibration generated on the crankshaft and transmitted to the inner ring causes shear resistance of the lubricating oil flowing through the narrow passage between the leaf spring of the outer ring fitted in the spline groove of the inner ring and the inertial force of the rotating wheel of the outer ring. I am trying to ease it.

<Problems to be Solved by the Invention> However, since the above-mentioned conventional tune damper fixes a large number of stacked leaf springs forming one block on the inner circumference of the outer ring alternately with the intermediate piece, the spring force is adjusted. In order to do so, it is necessary to replace them all with new members and fix them again, which has the drawback of making the adjustment complicated and time-consuming. Further, the damping coefficient of the damper is adjusted by changing the gap size between the leaf spring and the intermediate block, but similarly the adjustment becomes complicated and it is necessary to fill the gap with lubricating oil. There is a drawback in that the damper becomes expensive because a seal is required.

Therefore, an object of the present invention is to provide a damper that does not necessarily require a damping lubricating oil, is lower in cost, has a simpler structure, and is easier to maintain than a conventional damper.

<Means for Solving the Problems> In order to achieve the above object, the torsional vibration prevention damper of the present invention has a disk shape and has an annular groove on the outer periphery, one side being a drive shaft and the other side being driven. Fixed wheels that are fixed to the shafts respectively and that have elongated holes extending in the circumferential direction and penetrating in the axial direction,
A movable wheel fitted in the annular groove of the fixed wheel so as to be rotatable relative to it and having a long hole extending in the circumferential direction and penetrating in the axial direction;
A pair of spring bearings axially inserted in the elongated holes of the fixed wheel and the movable wheel, a coil spring having a non-linear characteristic compressed between the pair of spring bearings, and an annular block fixed to the outer peripheral edge of the movable wheel. It is characterized by having.

<Operation> For example, four disc-shaped fixed wheels, whose both sides are fixed to the drive shaft and the driven shaft, and a movable wheel, which is relatively rotatably fitted in an annular groove on the outer periphery of the fixed wheel, have, for example, four pieces each. Long holes penetrating in the axial direction are provided at equal intervals in the circumferential direction, and during the torsional vibration that occurs in the drive shaft at a specific rotation speed, between the spring receivers inserted in pairs in each long hole. It is assumed that the coil spring pre-compressed by the compressive force according to the torsional trike peak value is compressed. Now, when torsional vibration is generated in the drive shaft at the above-mentioned specific number of rotations and an excessive torsional torque acts in the forward rotation direction of the drive shaft, this torsional torque is generated by a fixed ring and a spring bearing.
Acts to compress the individual coil springs in the forward direction, and when the applied compression force exceeds the precompression force of the coil springs, the coil springs contract, and the movable wheel with the annular block as an inertia member rotates in the opposite direction. Then, a restoring force in the opposite direction having the same magnitude that cancels the above-mentioned torsion torque is instantly applied to the fixed wheel to rapidly damp the torsional vibration. Further, when the acting compression force is smaller than the pre-compression force of the spring, the relative motion between the fixed wheel and the movable wheel disappears, and no mutual force acts between the two wheels. The same effect is obtained in the reverse direction. In this way, the torsional vibration is damped and relaxed by utilizing the unstable region which is a non-linear characteristic.

<Examples> Hereinafter, the present invention will be described in detail with reference to illustrated examples.

1 and 2 are an axial sectional view and a radial sectional view showing an embodiment of a torsional vibration preventing damper. Reference numeral 1 is a drive shaft supported by a bearing 2 with a free end 1a protruding outward. A diesel engine crankshaft, 3 is a mounting sleeve fixed to the free end 1a of the crankshaft with bolts 4, 4, ..., 5 is a ring-shaped mounting flange that is externally fitted and fixed to the mounting sleeve 3, Reference numeral 6 is a ring-shaped flange 7 that axially overlaps the mounting flange 5 and an internal fitting that axially overlaps the flange 7 and that has a disk-shaped block 8 that has an annular groove 8b on the outer periphery and a recess 8c at the center. The fixed ring 10, which is integrally fixed to the mounting flange 5 and the mounting sleeve 3 with the bolts 9, ... Is fitted in the annular groove 8b of the block 8 of the fixed ring 6 so as to be rotatable relative to it, and extends in the circumferential direction. Four elongate holes 10a penetrating in the direction
(See FIG. 2) Movable wheel, 11 is the elongated hole 10a
And a pair of spring supports axially inserted into the long holes 7a and 8a provided in the fixed ring 6 so as to match the long holes,
Reference numeral 2 is a coil spring in which three pieces are compressed in parallel between the pair of spring receivers 11 and 11 (see FIG. 2).

Further, 13 is a holding ring fixed to the end surface of the block 8 of the fixed ring 6 by bolts 14, so as to come into contact with the end surface of the spring receiver 11, and 15 is screwed at the center of the end surface of the block 8 constituting the fixed ring 6. A central shaft 17 as a driven shaft which is attached and fixed by bolts 16, 16, ... Covers the mounting sleeve 3, the mounting flange 5, the fixed ring 6, and the movable ring 10, and the seal ring 18 of the cover plate 17a is attached. Center hole attached 1
7b is inserted through the central shaft 15 and fixed to the bearing 2 with bolts 19, 19, ..., 20 is a lubricating oil discharge nozzle fixed to the cover plate 17a, and 21 is the lubricating oil discharge nozzle 20. A lubricating oil supply hole provided so as to pass through the annular groove 8b from the end surface of the block 8 facing the
Is a lubricating oil discharge pipe connected to the lower end of the cover case 17.

As shown in FIG. 2, the elongated holes 7a, 8a and 10a have semi-circular shapes at both ends thereof.
1 is inserted. Each of the spring receivers 11 and 11 is provided with three round protrusions 11a so as to face each other, and both ends of the coil spring 12 are externally fitted and compressed to the opposing protrusions 11a and 11a. The lengths of the long holes 7a, 8a, 10a and the spring constant of the coil spring 12 are the sum of the spring forces of the 3 × 4 coil springs, and the maximum value T of the torsional torque at the time of torsional vibration generated in the crankshaft 1 at a specific rotation speed T Value according to _max Ts = α ・ T
The coil springs 12 are adjusted so as to be _max (0 <α <1), and the coil springs 12 are compressed into the elongated holes 7a, 8a, and 10a in a state where the total of the 3 × 4 precompression forces is the above value Ts. It is equipped.

Regarding the operation of the torsional vibration prevention damper configured as described above,
Next, referring to FIG. 4 and FIG.

FIG. 3 is a diagram schematically showing a cross section taken along the line III-III in FIG. 2 in the case where the number of the coil springs 12 compressed into the elongated holes 7a, 8a, 10a is one. The four coil springs 12 are contracted in the elongated holes as shown in FIG. 3 (a), and in this state, they are precompressed by a force of Ts / 4. Now, when the crankshaft 1 (see FIG. 1) is driven and reaches a specific rotation speed, torsional vibration occurs in the crankshaft, which causes the crankshaft to rotate in the forward direction (see arrow A in FIG. 1). An excessive torsion torque T acts, and this torsion torque T is transmitted to the fixed ring 6 including the flange 7 and the lock 8 via the attachment sleeve 3 and the attachment flange 5. Then, the twisting torque T
Exceeds the pre-compression force Ts of the four coil springs 12, the fixed wheel 6 moves the movable wheel 10 that rotates with inertial force in the same direction.
Relative to the slot 7 as shown in Fig. 3 (b).
spring receivers 11, 11 inserted in a, 8a and 10a
The coil spring 12 is pressed and contracted as shown in FIG. At this time, a restoring force of the same magnitude in the opposite direction acts so as to cancel the torsion torque T from the movable wheel 10 to the fixed wheel 6. That is, as shown by the solid line in FIG. 4, when the torsional torque T exerted on the movable wheel 10 from the fixed wheel 6 exceeds the precompression force Ts of the coil spring, the restoring force F (>) proportional to the relative rotation angle θ of both wheels. On the contrary, Ts) acts from the movable wheel 10 to the fixed wheel 6, whereby the torsion torque T is attenuated without reaching the maximum value T _max , and the torsional vibration generated in the crankshaft 1 is alleviated. On the other hand, when the torsional vibration causes an excessive torsional torque T in the reverse direction of the crankshaft, the fixed wheel 6 and the movable wheel 10 relatively rotate in the opposite direction as shown in FIG. 3 (c), By the compression of the coil spring 12, a restoring force F as shown by the solid line in the lower half of FIG. The broken line in FIG. 4 indicates the restoring force when the coil spring 12 is mounted between the spring receivers 11 and 11 without precompression,
Even if a slight torsional torque is generated by the torsional vibration, the restoring force that cancels the torque is still working. However, at that time, the fixed wheel 6 and the movable wheel 10 make a large relative rotation, and the relative angle between the two wheels when the torsional vibration is blocked. The same adverse effect as in the conventional example that the displacement cannot be suppressed low appears.

FIG. 5 is a partial detailed view of FIG. 1 showing a method for accelerating the damping of torsional vibration. In this method, an annular block 25 having an L-shaped cross section is fixed to the periphery of the movable wheel 10 by a plurality of bolts 26, and the coil spring 12 is compressed to face the fixed wheel 6 to increase the inertia of the movable wheel 10 and restore force. Is generated instantly and the torsional vibration is stopped rapidly.

According to the above-described embodiment, the sum of the precompression forces of the 3 × 4 coil springs 12 via the spring bearings 11 and 11 is Ts (= k.
・ T _max ), the fixed wheel 6 and the movable wheel 10 are compressed into the elongated holes 7a, 8a, 10a, so that the crankshaft 1
Since the two wheels 6 and 10 rotate relative to each other only after the excessive torsional torque T due to the torsional vibration of T exceeds Ts, there is an advantage that the relative angular displacement of both wheels during the operation of the damper can be suppressed to be low. Further, since the coil spring is contracted in the elongated hole penetrating both wheels via the spring receiver, the adjustment of the restoring force can be performed by replacing the coil spring 12 or the annular block 2.
This can be easily performed by adding 5 or the like as compared with the conventional example. Further, since the lubricating oil is supplied from the lubricating oil discharge nozzle 20 to the sliding contact portion between the fixed wheel 6 and the movable wheel 10 through the lubricating oil supply hole 21, the relative rotation of both wheels during operation becomes smooth.

Further, it is needless to say that the torsional vibration preventing damper of the present invention can be widely applied to not only the crankshaft of the diesel engine of the embodiment but also a rotating shaft that produces torsional vibration.

<Effects of the Invention> As is apparent from the above description, the torsional vibration prevention damper of the present invention has a disc-shaped fixing having an annular groove on the outer circumference and a slot extending in the circumferential direction and penetrating in the axial direction. One side of the wheel is fixed to the drive shaft and the other side is fixed to the driven shaft, and a movable wheel having an elongated hole similar to the elongated hole is relatively rotatably fitted in the outer peripheral annular groove of the fixed wheel, and Since the annular block is fixed to the outer peripheral edge of the movable wheel, and the coil spring having a non-linear characteristic is compressed in the elongated hole through a pair of spring receivers, lubricating oil is not always required as compared with the conventional tune damper. In addition, the structure is simple, the manufacturing cost is low, the spring constant is easy to adjust, and the relative angular displacement between the fixed wheel and the movable wheel during operation is kept low, and the torsional vibration of the drive shaft is rapidly attenuated. be able to.

[Brief description of drawings]

1 is an axial sectional view showing an embodiment of a torsional vibration preventing damper of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. FIGS. 4 and 5 are views for explaining the operating state of the above embodiment, and FIG. 5 is a partial detailed view of FIG. 1 with a mass block added. 1 ... Crank shaft, 1a ... Free end, 3 ... Mounting sleeve, 5 ... Mounting flange, 6 ... Fixed ring (7 ... Flange, 8 ... Block), 8b ... Annular groove, 10 ... Movable wheel, 11 ... Spring receiver, 12 ... Coil spring, 25 ... Ring block.

Claims (1)

[Claims] 1. A slotted hole having a disk shape and an annular groove on the outer periphery, one side fixed to the drive shaft and the other side fixed to the driven shaft, and extending in the circumferential direction and penetrating in the axial direction. A fixed wheel having a fixed wheel, a movable wheel fitted in the annular groove of the fixed wheel so as to be rotatable relative to each other, and having a long hole extending in the circumferential direction and penetrating in the axial direction; And a pair of spring receivers inserted in the axial direction, a coil spring having a non-linear characteristic compressed between the pair of spring receivers, and an annular block fixed to the outer peripheral edge of the movable wheel. Anti-vibration damper.