JP7110829B2 - dynamic damper - Google Patents

Description

The present invention relates to a dynamic damper that damps bending vibration transmitted from a rotating member.

As shown in FIGS. 7(a) and 7(b), in an internal combustion engine (engine) such as a vehicle, the crankshaft 51 vibrates (deforms) due to combustion and reciprocating inertial force of the piston, and this is one of the engine noises. be a factor. For this reason, a dynamic damper 52 is generally attached to the crankshaft 51 to suppress vibrations generated in the crankshaft 51 (see Patent Document 1, etc.). This type of dynamic damper 52 absorbs or reduces the vibration of the crankshaft by penetrating through holes 53 corresponding to the resonance frequency of the vibration of the crankshaft 51 at a plurality of locations.

JP-A-2002-139103

By the way, when the crankshaft 51 vibrates, due to the structure and shape of the crankshaft 51, there is a current situation in which a plurality of resonance frequencies are generated during rotation. Specifically, for example, the resonance frequency are different. However, since only one pattern of resonance frequency is set in the dynamic damper 52, there is a problem that vibrations of multiple patterns occurring in the crankshaft 51 cannot be sufficiently suppressed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dynamic damper capable of ensuring vibration damping performance.

A dynamic damper that solves the above problem is attached to a rotating member that rotates about an axis, and has a structure that suppresses vibration generated in the rotating member. On the other hand, the damper body is provided with an adjustment unit for generating a resonance frequency in the damper body according to the bending direction.

According to this configuration, since the dynamic damper is provided with the adjustment unit capable of generating a plurality of resonance frequencies, it is possible to cope with a plurality of resonance frequencies. Therefore, when the rotating member rotates, even if vibrations in different directions are generated in the rotating member and multiple patterns of resonance frequencies are generated in the dynamic damper, it is possible to match the resonance frequency of the dynamic damper to these resonance frequencies. becomes possible. Therefore, it is advantageous for securing the vibration damping performance of the dynamic damper.

FIG. 2 is an assembly diagram of the dynamic damper of the embodiment; Front view of the dynamic damper. (a) is a state diagram when the dynamic damper is vertically bent, and (b) is a state diagram when the dynamic damper is horizontally bent. (a) is a diagram showing the strain that occurs in the dynamic damper when it is vertically bent, and (b) is a diagram that shows the strain that occurs in the dynamic damper when it is horizontally bent. The front view of the dynamic damper of another example. II-II line sectional view of FIG. It is a schematic diagram which shows the conventional resonance example, (a) is a figure at the time of vertical bending, (b) is a figure at the time of left-right bending.

An embodiment of the dynamic damper will be described below with reference to FIGS. 1 to 4. FIG.
As shown in FIG. 1, in an internal combustion engine 1, a crankshaft 3 as a rotating member 2 installed over a plurality of cylinders (not shown) is rotatable around an axis La (in the direction of arrow R in FIG. 1). is provided. The crankshaft 3 is provided with a piston (not shown) that linearly reciprocates between the upper and lower dead centers in each cylinder.

One end of the crankshaft 3 is provided with a dynamic damper 5 that suppresses bending vibrations applied from the crankshaft 3 when the crankshaft 3 rotates, and a drive plate 7 to which a torque converter 6 of an automatic transmission is attached and fixed. . The dynamic damper 5 and the drive plate 7 are fastened together to the end face of the crankshaft 3 with a plurality of fasteners 8. The fasteners 8 are preferably bolts, for example. In the dynamic damper 5 and the drive plate 7, the fastener 8 is passed through the insertion hole 9 of the dynamic damper 5 and the fastening hole 10 of the drive plate 7, and the fastener 8 is inserted into the fastening hole provided in the end face of the crankshaft 3. 11, it is attached and fixed to the crankshaft 3. The fastener 8 is attached to the drive plate 7 with a plate-shaped interposed member 12 interposed therebetween.

The dynamic damper 5 is made of metal and has a substantially disk shape. A center hole 13 through which the end of the crankshaft 3 is passed is formed in the center of the dynamic damper 5 . A plurality of insertion holes 9 of the dynamic damper 5 are provided around the central hole 13 . The dynamic damper 5 suppresses bending vibration of the crankshaft 3 by operating as, for example, a dynamic damper elastic body or mass body. Also, the dynamic damper 5 is formed in such a shape and weight that its own natural frequency (resonance frequency) is the same as or similar to the natural frequency (resonance frequency) of the bending vibration of the crankshaft 3 . The natural frequency of the crankshaft 3 is a specific frequency included in the range of frequencies that can occur in the bending vibration of the crankshaft 3 during rotation.

The drive plate 7 is made of metal and has a substantially disk shape. The drive plate 7 of the present example maintains rigidity in the rotational direction, but has flexibility in the same direction by lowering rigidity in the planar direction. The drive plate 7 includes a constricted portion 16 located on the inner diameter side and a flat plate portion 17 located on the outer diameter side. A central hole 18 through which the end of the crankshaft 3 is passed is formed in the center of the drive plate 7 (throttled portion 16). The drive plate 7 is formed with a diameter larger than that of the dynamic damper 5 .

Torque converter 6 is attached and fixed to drive plate 7 by a plurality of fasteners 19 . Fasteners 19 are preferably bolts, for example. The torque converter 6 is attached and fixed to the drive plate 7 by inserting the fastener 19 through the insertion hole 20 of the drive plate 7 and fastening the fastener 19 to the fastening hole 21 provided in the torque converter 6 . there is

As shown in FIG. 2, the dynamic damper 5 also serves as a sensor plate used for detecting rotation of the dynamic damper 5 (crankshaft 3). In this case, the damper main body 24 of the dynamic damper 5 has a plurality of protrusions 26 protruding from the peripheral edge thereof, which are detected by sensors 25 (see FIG. 1) facing each other. The protrusions 26 are arranged at regular intervals along the circumferential direction of the dynamic damper 5 . The sensor 25 detects rotation of the dynamic damper 5 by detecting these protrusions 26 .

A plurality of holes 27 are provided through the dynamic damper 5 (damper body 24 ) along the center P of the dynamic damper 5 . These holes 27 are portions for lowering the resonance frequency of the dynamic damper 5 and are arranged at regular intervals in the circumferential direction of the dynamic damper 5 .

The dynamic damper 5 includes an adjuster 28 that generates a plurality of resonance frequencies in the damper body 24 . The adjustment unit 28 of this example causes the damper body 24 to generate a resonance frequency corresponding to the bending direction in the damper body 24 to which the load of bending vibration is applied when the dynamic damper 5 rotates together with the crankshaft 3 . The adjusting portion 28 is formed of a portion (a notch for adjusting the corner R) of the plurality of holes 27 formed in the damper main body 24 in the circumferential direction and having a "small" corner R. As shown in FIG. A portion of the hole portion 27 that is not the adjustment portion 28 has a "large" corner R. As shown in FIG. Of the plurality of holes 27, the hole 27a having the adjusting portion 28 has a larger hole area (opening area) than the hole 27b having no adjusting portion 28. As shown in FIG.

Next, the action and effect of the dynamic damper 5 of this embodiment will be described with reference to FIGS. 2 to 4. FIG.
As shown in FIGS. 3(a) and 3(b), the crankshaft 3 has a complicated shape and has different resonance frequencies for vertical vibration and horizontal vibration. Different resonance frequencies are generated in vertical bending and horizontal bending. In the case of FIG. 3, FIG. 3(a) shows the dynamic damper 5 in a vertically bent state, and FIG. 3(b) shows the dynamic damper 5 in a horizontally bent state.

Therefore, as shown in FIG. 2, in order to set the resonance frequency of the dynamic damper 5 according to the bending direction, the area in the plane direction of the dynamic damper 5 is divided into areas according to the bending direction. In the case of this example, the dynamic damper 5 is equally divided into four parts (areas A to D) in the circumferential direction. Let it be a region related to resonance. Thus, regions A and C are one set related to up-down bending, and regions B and D are another set related to left-right bending.

By the way, the resonance frequency of the dynamic damper 5 is determined by, for example, the spring and the mass. Spring is spring constant and mass is mass. Therefore, the resonance frequency of the dynamic damper 5 can be changed for vertical bending and horizontal bending by partially changing the spring or mass. In this example, the spring (spring constant) of the dynamic damper 5 is partially changed by changing the opening area of the hole 27 .

In the case of this example, the opening areas of the holes 27a related to the regions B and D are set to be large, and the opening areas of the other holes 27b are set to be small. implement the switch. Here, the size of the opening areas of the holes 27a and 27b is changed by changing the size of the corner R. That is, setting the corner R to "small" increases the opening area of the hole 27a, and setting the corner R to "large" reduces the opening area of the hole 27b. Note that the hole 27b has a conventional shape, and in this example, the shape (size) of the conventional hole 27b is processed to create a new hole 27a having the adjusting portion 28 .

FIG. 4(a) shows a strain generating portion 31 that occurs in the dynamic damper 5 when the dynamic damper 5 is in a vertically bent state. As shown in the figure, when the dynamic damper 5 is bent up and down, distortion (distortion generation portion 31: the portion indicated by dots in the figure) occurs around the hole 27b having a small opening area. In this example, the spring constant of the strain generating portion 31 becomes “large” due to the portion of the hole portion 27 having the “large” corner R. As shown in FIG. For this reason, the resonance frequency of the strain generating portion 31 is set high, so that the resonance frequency is set according to the vertical bending vibration of the crankshaft 3 .

FIG. 4(b) shows a strain generating portion 32 that is generated in the dynamic damper 5 when the dynamic damper 5 is bent left and right. As shown in the figure, when the dynamic damper 5 is in the laterally bent state, distortion (distortion generation portion 32: the portion indicated by dots in the figure) occurs around the hole 27a having a large opening area. In this example, the spring constant of the strain generating portion 32 is "small" due to the "small" corner R of the hole portion 27 . For this reason, the resonance frequency of the strain generating portion 32 is set low, so that the resonance frequency is set according to the bending vibration of the crankshaft 3 in the left-right direction.

In the case of this example, since the dynamic damper 5 is provided with the adjustment unit 28 capable of generating a plurality of resonance frequencies, it is possible to deal with a plurality of resonance frequencies. Therefore, when the crankshaft 3 rotates, even if vibrations in directions different from each other occur in the crankshaft 3 and multiple patterns of resonance frequencies occur in the dynamic damper 5, the resonance frequencies of the dynamic damper 5 do not coincide with these resonance frequencies. can be combined. Therefore, it is advantageous for securing the vibration damping performance of the dynamic damper 5 .

In addition, this embodiment can be changed and implemented as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- As shown in FIGS. 5 and 6, the adjustment portion 28 may be a bead formed by raising a portion of the damper body 24 . The beads are linear extending in the radial direction of the dynamic damper 5 and are arranged at equal intervals in the circumferential direction. In the case of this example, the resonance frequency generated in the dynamic damper 5 is changed depending on the presence or absence of the bead. That is, by forming the bead groups only in the regions A and C, the resonance frequencies that can occur in each of the regions A and C (vertical bending) and the regions B and D (horizontal bending) are changed. Thus, the dynamic damper 5 can have a plurality of resonance frequencies by the simple structure of forming the beads on the dynamic damper 5 .

The hole portion 27 does not have to have a hole shape with a "large" corner R on one side and a "small" corner R on the other side. That is, the hole portion 27 may consist of a hole with only a "large" corner R and a hole with only a "small" corner R.

- In the case of a notch for adjusting the corner R, the adjusting section 28 may appropriately change the shape of the notch to another shape other than the shape of the embodiment. Moreover, the shape of this notch may be changed for each part.
- The adjustment portion 28 is not limited to a through hole, and may be a hole with a bottom, for example.

- The adjusting portion 28 is not limited to a notch for adjusting the corner R or a press-molded ridged bead. For example, it may be changed to another shape such as an independent hole different from the hole 27 penetrating through the dynamic damper 5 .

- The adjustment unit 28 is not limited to changing the spring constant to provide a plurality of resonance frequencies. For example, focusing on changing the mass of the dynamic damper 5, a plurality of resonance frequencies may be generated. .

- The number of resonance frequencies to be given to the dynamic damper 5 is not limited to two.
- The dynamic damper 5 is not limited to having a sensor function, and may have a structure in which the sensor function is omitted.

- As for the size and shape of the dynamic damper 5, an optimum pattern can be adopted as needed.
・The rotating member 2 is not limited to the crankshaft 3, and may be an element that constructs an internal combustion engine or its peripheral parts.

2 Rotating member 3 Crankshaft 5 Dynamic damper 24 Damper body 28 Adjusting part La Shaft.

Claims (3)

A dynamic damper that is attached to a rotating member that rotates about an axis and suppresses vibration generated in the rotating member,
comprising a damper body that is subjected to a bending vibration load when rotating with the rotating member;
The damper body has a plurality of protrusions protruding from the periphery, and functions as a sensor plate in which the protrusions are detected by a sensor provided at a position facing the protrusions,
A dynamic damper comprising an adjusting section for generating a resonance frequency in the damper body according to a bending direction of the damper body. The damper body has a plurality of holes,
Among the plurality of holes, the opening area of the hole having the adjusting portion is larger than the opening area of the hole not having the adjusting portion.
A dynamic damper according to claim 1. The adjustment part is a bead formed by a raised part of the damper body.
A dynamic damper according to claim 1.

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