JPS62171543A - Two-line support pendulum type vibration absorber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a crankshaft vibration damper for an automobile, and more particularly to the structure of a two-wire supported pendulum type damper.

Prior Art Problems to be Solved by the Invention and Means for Solving the Problems The two-wire support pendulum damper suppresses engine vibration by tuning the pendulum body to a natural frequency equal to the crankshaft excitation frequency. It is well known for.

For example, U.S. Patent No. 3,932.060, U.S. Pat.
No. 4.734, No. 2.306,959, No. 3.5
No. 40,809, No. 2.272.189, No. 2,
No. 535.958, No. 4,218.187, and British Patent No. 401,962 all demonstrate the utility of two-wire supported pendulum dampers for balancing or canceling undesirable orders of vibration in engines. ing. In these cases, the crankshaft, in an attempt to maintain a constant synchronous or isochronous action on the pendulum, so that all engine oscillations of orders higher than or equal to - are precisely balanced, IJ Tj is connected to the pendulum body by a roller that moves in a circular, cycloidal, or epicycloidal path in one.

783.3 for U.S. Patent Application filed October 3, 1985
No. 86 and U.S. Patent Application Ser.
A two-wire support pendulum damper designed to prevent mechanical damage to the device is illustrated and described. The pendulum body at low amplitude swing angles almost completely cancels out engine vibrations due to the following of the rollers along a path that produces an approximately isochronous movement of the pendulum. At higher, ie larger amplitudes, devices are provided for self-help detuning of the pendulums, in other words they become progressively less tuned to the excitation frequency of the crankshaft. This results in a gradual reduction in the pendulum's response to vibration shock, which limits the amplitude at higher torsional vibration excitation levels and maintains the pendulum within its oscillating range.

The invention described herein is more particularly described in U.S. Pat.
Regarding the two-wire supported pendulum damper of the type disclosed in the
Is the structure better than the conventional two-wire supported pendulum damper shown in the above patented prior art? ! 2. Not sloppy. More particularly, it relates to a damper having a low operating noise level.

In conventional crankshaft pendulum assemblies, the pendulum is generally sized, for example, by W. Kerr Wilson (-1).
) e rPractical Solutions of
Torsional vibration problems (Pr
actual 5 solutions or Tors
ional Vibration Problems)
J, Volume 4 “Devices for Controlling Vibrations”
Controlling Vibrations) J
, Figures 30 and 17 on page 661 of the 3rd edition (continuous)
As shown, both are located on the crankshaft itself.

However, this requires precision machining at a somewhat awkward location on the crankshaft. Alternatively, the pendulums can be placed on bolted-type carriers, in which case they can be placed, for example, in Wilson (Wisson, cited above).
1son)'s Meisho, Figures 29-17 and 30.1
As shown in Figure 9, it can only be attached to both ends of the crankshaft.

In the assembly of the invention, the carrier is mounted on a turned diameter with flats to prevent rotation of the carrier relative to the crankshaft. A clamp similar to a main bearing cap holds the assembly in place. This makes it possible to attach the pendulum on each side of the crankshaft along the contour without performing any precision machining on the crankshaft itself.

In conventional pendulum assemblies, hardened steel pendulum rollers move in one direction near their ends and in the opposite direction in the middle when the pendulum is mounted across a carrier by a yoke-type connection. added. The rollers are thereby subjected to high contact, bending and V-shear stresses. Additionally, to reduce contact stress between the rollers and the crankshaft wear, the crankshaft wear received within the pendulum yoke must be much thicker than the length of the roller required to support its tensile loads. The thickness is only half that of [
I have to. This means that the crankshaft wear occupies space that could otherwise be used to increase the effectiveness of the pendulum body and thus the pendulum.

In the assembly of the invention, the width of the roller is approximately the same as the width of the pendulum and carrier so that both the pendulum and carrier load the rollers over their entire length. This removes bending and shear loads and reduces contact stresses.

Also, the pendulum occupies almost the entire thickness of the assembly.

In conventional pendulum assemblies, the pendulum is stopped at the end of its swing, usually by metal-to-metal contact. Although this is not expected to occur during normal engine operation, it can create significant noise during engine starts and stops where the crankshaft is rotated at low speeds. The centrifugal force acting on the pendulum can then be overcome by gravity. This causes an alternating movement of the pendulum, first downwards inward toward and opposite the crankshaft, and then outwards to be stopped by the rollers. In addition to the noise caused by moving inward against the crankshaft,
- Noise is generated by the impact on the roller.

In the carrier assembly of the present invention, a stop pin is mounted on the cover'plate of the carrier proximate a camming surface formed on the radially inner portion of the pendulum. During normal pendulum operation, there is a small radial clearance between the pin and the pendulum throughout the pendulum's swing. However, during low-speed operation, as gravity pulls the pendulum inward against centrifugal force, the cam comes into contact with the pin, forcing the pendulum to follow a path very similar to that followed by the pendulum during normal operation. let This ensures that the pendulum and 0-ra have very little clearance from the pendulum to the rollers to the carrier when the pendulum is thrown outwards again, thus minimizing shock and noise during the next contact with the carrier. be kept in the proper position so that

Therefore, the main object of the present invention is to be simple in structure and assembly;
Provided is a two-wire support pendulum damper having a device 6 that facilitates installation on an engine crankshaft, eliminates shear and bending loads on rollers, and suppresses pendulum motion at low speeds to reduce noise. It's about doing.

Another object of the invention is to provide a two-wire supported pendulum damper of the type described above, comprising a device for adjusting the center of gravity of the pendulum in order to allow a change in the tuning of the pendulum.

Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the invention and the drawings showing preferred embodiments thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS AND OPERATIONS The two-wire supported pendulum damper known in the prior art mentioned above is equipped with circular rollers operating in circular or other shaped holes in both the crankshaft and the pendulum body. . As a result, the amplitude or swing angle of the pendulum body gradually increases in proportion to the increase in excitation force or vibration.

Also thereby, the above-cited U.S. Pat. No. 4.218
As pointed out in FIGS. 6 and 7 of , No. 187, increasing swing angle results in a progressive +mt tuning of the pendulum body.

FIG. 1 is a perspective view of one two-wire support pendulum damper assembly 10 fastened to the crankshaft 12 of a motor vehicle engine by the side surface 14 of the connecting rod pin. It is clear that as many as eight sets of the above jγ bodies can be attached to the crankshaft of the four cylinders in series 1111 as desired. FIG. 2 more clearly shows the construction of a set of assemblies. 40 is a one-piece U-shaped pendulum rear member having an opening 42 adapted to straddle the side 14 (FIG. 1) of the engine crankshaft 12. This side part of the crankshaft has an arcuate part 4 fitted into the opening of the carrier A7, which is held in the ring by a clamp 44 screwed onto the carrier.
3 are provided.

The carrier assembly shown for this particular case uses two sets of primary two-wire support pendulums 46 and one set of tertiary two-wire support pendulums 48, which are tuned to respond to vibrations of respective characters. Designed to balance secondary translational vibrations. The carrier and pendulum are interconnected by pairs of rollers 50 that are movable on paired curved track surfaces 52,54. This raceway surface is an arc of overlapping holes configured as described above. That is, the hole profile essentially starts out as a circular path of constant radius for the first ±15° advance of the roller, and the hole profile, O-La raceway, then follows a circular path with an amplitude of 15°. It has a radius of curvature that gradually decreases as the swing angle increases, making the pendulum progressively less responsive to the excitation frequency of the crankshaft and carrier 40, as described above.

As seen in Figures 2 and 3, each pendulum 46.4
8 is mounted floating in the cavity of the carrier between the crankshaft mounting section 42 on the one hand and the shaped roller raceway surface 52 of the carrier on the other hand, with the roller 50 intermediate. The rollers and pendulum are laterally constrained by a pair of front and rear cover plates 56, 58, with front plate 56 removed for clarity in FIGS. 1 and 2.

Referring specifically to the pendulum 48 as an example, and noting that pendulums of other orders can be similarly constructed, FIG.
is shown as having a central threaded hole 60 that changes the tuning of the pendulum as well as its internal swinging motion. More specifically, a weight adjustment screw 62 is threaded into hole 60 and can be moved vertically to shift the location of the pendulum's center of gravity and change its natural frequency or tuning. This is useful, for example, when it is desired to retune various pendulums for testing and other purposes. Also shown is an adjustment bumper screw 64 that limits the eight ribs to the innermost part of the pendulum.

FIG. 2 and FIG. 3 will be explained. The inner surface of the pendulum G is provided with an axially and radially extending recess 66 with a shaped curvature U68 serving as a cam surface. This cam surface operates in conjunction with a stop pin 70 secured to the carrier front cover plate 56. The shape of the cam surface is as follows: ■ When the pendulum receives centrifugal force and touches outward in an arc shape during operation at normal engine speed, there is always a slight radial gap between the pin and the cam surface. However, when ground, the shape is such that the pin actually follows the normal orbital plane or path of the pendulum without leaving a slight gap h' between them. Then, during operation at low rotational speeds when gravity overcomes the centrifugal force acting on the pendulum, the cam surface is included in the pin 70 due to the inward movement of the folding element, and the pendulum returns to its normal state at high rotational speeds. It can be made to follow almost the same path as the one in motion.

As mentioned above, the pendulum and roller 50 are moved by the following movement of the cam.
means that when the pendulum is thrown outward again, it joins the roller*
*The bumper 64 is held in a position suitable for reducing noise and, conversely, minimizing the impact and noise of the bumper 64 on the carrier.

In order to further reduce the impact of the metal-on-metal impact contact between the carrier and the pendulum at the ends of the pendulum swing, and thus the noise level, each pendulum can also be provided with an elastomeric bread buff 2 at the base or inside surface. .

Although the present invention has been illustrated and described with reference to preferred embodiments thereof,
It will be apparent to those skilled in the art that numerous changes and modifications can be made without departing from the scope of the invention.

[Brief explanation of drawings]

1 is a perspective view of a two-wire supported pendulum damper constructed in accordance with the present invention, mounted on the crankshaft of an engine; FIG. 2 is shown in FIG. 1 with the carrier end cover plate removed for clarity; Enlarged end view of a two-wire supported pendulum damper,
FIG. 3 is a sectional view of the plane indicated by the arrows ■--■ in FIG. 2 and viewed in that direction.

Claims (5)

[Claims] (1) A hollow pendulum carrier fixed to the engine crankshaft to rotate with it; a pendulum body floatingly contained within the carrier between the periphery and a roller movably contained between a curved track surface formed by overlapping aperture walls of the carrier and the pendulum; The inner radial surface of the pendulum and the adjacent portion of the carrier are formed together to define a cam and a cam follower, and the swinging of the pendulum is subjected to centrifugal forces at normal engine crankshaft operating speeds. The arcuate outward actuation swings the pendulum so that a small radial clearance is obtained between the cam and the cam follower, and the change in actuation at low rotational speeds allows for alternate engagement of the cam and the cam follower and When detachment occurs, gravity first acts on the pendulum, overcoming the centrifugal force, and then forces the pendulum to follow the same path as during operation at normal speed, thereby causing the pendulum to rotate inward in this way. A two-wire support pendulum type vibration absorption device for an internal combustion engine for an automobile, in which the shock of contact between a pendulum and a roller or a pendulum and a carrier, as well as the noise level, are reduced when moving inward and outward. (2) In the absorption device according to claim 1, the pendulum has a recess extending in the axial direction and the radial direction on the innermost surface thereof defining the cam driven surface, and the carrier is mounted on the recess that extends in the axial direction and the radial direction. An absorption device in which a pin close to a driven device is fixed. (3) In the absorption device according to claim 1, the cam and the cam follower are constituted by a cam-shaped curved surface on the inner radial edge portion of the pendulum and a pin fixed to the carrier. An absorption device in which the curvature defines a path substantially identical to the arcuate path that a pendulum may take during higher normal engine rotational operating speeds. (4) An absorption device according to claim 1, wherein the pendulum includes an adjustable weight device that can be moved to change the position of the center of gravity and the resulting tuning of the pendulum. . (5) The absorption device according to claim 4, wherein the pendulum includes a radially extending threaded hole for threadably receiving the adjustable weight.