JP2007255679A - Dynamic damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and lightweight dynamic damper whose natural frequency is easily adjusted. <P>SOLUTION: The dynamic damper comprises a cylindrical case 2, covers 3a, 3b detachably provided at both ends of the case 2, a guide bar 5 passing through the covers 3a, 3b and the case 2, fasteners 7 detachably provided at both ends of the guide bar 5, a plurality of weights 9a, 9b slidably provided on the guide bar 5, and a pair of springs 10 provided in the case 2 for energizing the weights 9a, 9b in the opposed directions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dynamic damper, and more particularly to a dynamic damper and a diesel engine in which the dynamic damper is applied for vibration isolation of an exhaust collecting pipe of the diesel engine.

  In recent years, a power plant using a large-sized low-speed diesel engine has attracted attention because of its low fuel consumption and easy maintenance. These large low-speed diesel power generation engines generally have a rated rotational speed of 100 to 200 rpm and an output number of around several thousand kW to 50,000 kW.

  However, since the exhaust collecting pipe of this type of large-scale low-speed diesel power plant is installed at the upper part of the exhaust side of the main engine (diesel engine), it vibrates greatly with the vibration of the main engine and supports the exhaust collecting pipe. There were problems such as cracks in the supporting support.

  In order to prevent vibration of the exhaust collecting pipe of a diesel engine, it is conceivable to attach a vibration isolating device to the support support that supports the exhaust collecting pipe, but a wet type vibration isolating device that circulates lubricating oil, that is, FIG. 11, the weight 103 is suspended in a swingable manner in the casing 101 via a lifting tool 102, and a large number of coil springs 104 are provided between the left and right side surfaces of the weight 103 and the left and right inner surfaces of the casing 101. When the vibration isolator 107 (see, for example, Patent Document 1) in which the lubricating oil 105 is supplied into the casing 101 through the pipe 107 is provided in a multi-stage manner. The lubricating oil 105 leaks from the joint between the pipe 101 and the pipe 107, or a damaged part of the pipe 107, and the surroundings are contaminated, or the exhaust collecting pipe High temperature (e.g., about 80 to 200 ° C.) the lubricating oil 105 that has leaked from the fact that there is a fear such cause fire.

Further, as described above, since the conventional vibration isolator for the main machine suspends the heavy weight 103 in the casing 101, the overall weight of the vibration isolator becomes excessive and the handling thereof becomes difficult. Therefore, it was necessary to reinforce the support support that supports the exhaust collecting pipe of the diesel engine.
Japanese Patent No. 2655294

  The present invention has been made to solve such problems, and a first object thereof is a dynamic damper that is relatively lightweight and does not need to reinforce a support support, and can easily adjust a natural frequency. Is to provide.

  A second object of the present invention is to provide an exhaust manifold anti-vibration type diesel engine that suppresses vibration of the exhaust manifold of the diesel engine.

  In order to solve the above problems, the present invention is configured as follows.

  According to the first aspect of the present invention, a cylindrical case, a cover detachably provided at both ends of the case, a guide bar penetrating the cover and the case, and detachably provided at both ends of the guide bar A dynamic damper comprising: a tightening tool; a plurality of weights slidably provided on the guide bar; and a pair of springs in the case for biasing the weights in an opposing direction.

  The invention according to claim 2 is the dynamic damper according to claim 1, wherein a vibration system is constituted by the weight and the spring.

  The invention according to claim 3 is the dynamic damper according to claim 1, wherein a hole for penetrating the guide bar is provided in the weight, and a slider is provided in the hole.

  According to a fourth aspect of the present invention, the spring guide adjacent to the weight is provided with a lateral measuring pin, and the case is provided with a longitudinally elongated opening for protruding the measuring pin in the case. It is a damper.

  According to a fifth aspect of the present invention, the exhaust collecting pipe of the diesel engine is installed on a gantry provided in parallel with the crankshaft of the diesel engine, and the dynamic damper according to the first aspect is provided at both front and rear ends of the gantry. The diesel engine is provided in a direction intersecting with a crankshaft of the diesel engine.

  According to a sixth aspect of the present invention, the gantry is formed by a rectangular top plate parallel to the crankshaft of the diesel engine and a number of support columns that support the top plate, and at both front and rear ends of the top plate. The diesel engine according to claim 5, wherein the dynamic damper according to claim 1 is provided in a direction intersecting with a crankshaft of the diesel engine.

  As described above, the dynamic damper according to the first aspect of the present invention includes a cylindrical case, covers that are detachably provided at both ends of the case, a guide bar that penetrates the cover and the case, A fastener provided detachably on both ends of the guide bar, a plurality of weights slidably provided on the guide bar, and a pair of springs in the case for urging the weights in an opposing direction Since it is configured, it has the following effects.

  (1) While being a small and lightweight dynamic damper, it is possible to reduce vibration of a large object such as a collective exhaust pipe of a diesel engine.

  (2) Since it is small and light, it is easy to handle.

  (3) A power source for operating the weight is not required.

  (4) Since a general steel pipe for piping is used as a dynamic damper case, it can be manufactured easily and inexpensively.

  (5) The natural frequency of the dynamic damper can be easily adjusted by changing the weight arrangement.

  (6) The dimensions of the dynamic damper do not change even if the weight arrangement is changed.

  (7) Even if the exhaust collecting pipe of the diesel engine vibrates after the operation of the main engine body (diesel engine) starts, it is possible to suppress the vibration of the exhaust collecting pipe of the diesel engine by changing the weight arrangement.

  In the invention according to claim 2, since the vibration system is configured by the weight and the spring, it is easy to set the natural frequency of the dynamic damper.

  In the invention according to claim 3, since a hole for penetrating the guide bar is provided in the weight, and a slider is provided in the hole, not only the oil supply device becomes unnecessary, but also the maintenance check of the oil supply device is performed. It became unnecessary.

  According to a fourth aspect of the present invention, since a measuring pin in the transverse direction is provided in the spring guide adjacent to the weight, and an elongated opening in the longitudinal direction for protruding the measuring pin is provided in the case, the weight is operated. The state can be easily confirmed or monitored from the outside.

  According to a fifth aspect of the present invention, the exhaust collecting pipe of the diesel engine is installed on a gantry provided in parallel with the crankshaft of the diesel engine, and the dynamic damper according to the first aspect is provided at both front and rear ends of the gantry. Since it is provided in a direction intersecting with the crankshaft of the diesel engine, it is possible to easily suppress the vibration of the exhaust collecting pipe of the diesel engine without making the mount solid.

  According to a sixth aspect of the present invention, the gantry is formed by a rectangular top plate parallel to the crankshaft of the diesel engine and a number of support columns that support the top plate, and at both front and rear ends of the top plate. Since the dynamic damper according to claim 1 is provided in a direction intersecting with the crankshaft of the diesel engine, vibration of the exhaust collecting pipe of the diesel engine can be easily suppressed without making the mount particularly strong. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the dynamic damper 1 uses a general steel pipe for piping in a cylindrical elongated case 2 serving as a damper body.

  The case 2 has a cap-shaped cover 3a detachably fitted to one end thereof and a cap-shaped cover 3b detachably fitted to the other end. These covers 3a and 3b have a through-hole 4 through which the guide bar 5 passes in the center.

  The guide bar 5 is an elongated rod having a circular cross section, and includes a cover 3a, a case 2, and a cover 3b. The guide bar 5 has screw portions 6 at both ends thereof, and nuts 7 as fasteners are screwed to the screw portions 6. In the figure, reference numeral 8 denotes a locking washer.

  Further, the guide bar 5 is made up of weights 9a and 9b, a coil spring 10 and spring guides 11a and 11b incorporated in the case 2. The weights 9a and 9b use a steel disc having a diameter smaller than the inner diameter of the case 2 and have a through hole 12 for allowing the guide bar 5 to pass through the center.

  The weight 9a is a thick heavy weight (hereinafter referred to as a heavy weight), and the weight 9b is thinner than the heavy weight 9a (hereinafter referred to as a light weight). .) A plurality (for example, five) of heavy weights 9 a and a plurality of (for example, four) small weights 9 b are provided in the central portion of the guide bar 5.

  Further, a pair of coil springs 10, 10 are provided outside the weight group. Both ends of the coil spring 10 have a through-hole 13 for allowing the guide bar 5 to pass through at the center, and a pair of railway wheel-type spring guides 11a and 11b having a hook-shaped spring receiving portion 14 on the outer peripheral portion. It is supported.

  Further, on the heavy weight 9a side (left side in the figure), a plurality of (for example, three) small weights 9b are placed on standby between the cover 3a and the first spring guide 11a. On the small weight 9b side (right side in the drawing), a single (for example, one) small weight 9b is placed between the second spring guide 11b and the cover 3b.

  The through hole 12 provided in the heavy weight 9a is provided with a linear bush (slider) 15 so that it is not necessary to supply lubricating oil. A cylindrical spacer 16 is provided in the through hole 12 provided in the heavy weight 9a and the small weight 9b.

  The pair of left and right coil springs 10, 10 already described biases a plurality of heavy weights 9 a provided in the central portion of the guide bar 5 and a plurality of small weights 9 b in a facing direction. The vibration system 20 is configured by a pair of left and right coil springs 10, 10 and a plurality of heavy weights 9a and a plurality of small weights 9b interposed therebetween.

  Further, a plurality of pin holes 17 are formed on one side (outer end surface) of the heavy weight 9a located at the left and right ends, both inner and outer surfaces of the light weight 9b, and one side (rear surface) of the spring guides 11a and 11b. Are provided concentrically. In addition, connecting pins 18 are attached to these pin holes 17 to couple adjacent members (weight 9a, weight 9b, spring guide 11a, spring guide 11b).

  Further, a measuring pin 19 in the lateral direction is screwed to the first spring guide 11a adjacent to the light weight 9b constituting the vibration system 20, and the measuring pin protrudes into the case 2. An elongated opening 21 is provided in the longitudinal direction.

  As shown in FIG. 2, the case 2 is attached to the base 23 by a plurality of support plates 22. The base 23 is attached to the plate 25 via a bracket 24.

  The shape of the case 2 is not limited to a cylindrical shape, and there is no problem even if it is a rectangular tube shape. However, when the shape of the case 2 is a rectangular tube, the weights 9 a and 9 b may be square according to the shape of the case 2. Further, when mounting on a high-temperature device such as an exhaust collecting pipe of a diesel engine, it is necessary to attach a heat shield or to provide a heat radiating hole (not shown) in the case 2 in order to prevent the temperature from becoming high. is there.

  Here, when a vibration model as shown in FIG. 3 is considered, the natural frequency f of the dynamic damper can be expressed by the following equation.

That is,
f ∝ √ (K / M) = √ (k / m)
In addition,
M: Mass corresponding to exhaust collecting pipe of diesel engine K: Spring constant of gantry of exhaust collecting pipe m: Mass corresponding to vibration system of dynamic damper k: Spring constant corresponding to vibration system of dynamic damper.

  Therefore, according to the present invention, it is possible to easily change the natural frequency f of the dynamic damper 1 by increasing or decreasing the number of small weights 9b constituting the vibration system 20 of the dynamic damper 1. .

  That is, the weight mb of the small weight constituting the vibration system 20 of the dynamic damper 1 is transferred to the standby position on the right side of the case 2 as indicated by the arrow a, and the mass m of the vibration system 20 of the dynamic damper 1 is set. Is reduced, the natural frequency f of the dynamic damper 1 can be increased (see FIG. 4).

On the other hand, as shown by arrows b and c, the small weight 9b waiting at the left and right standby positions of the case 2 is transferred to the vibration system 20 located at the center of the dynamic damper 1 to dynamically When the mass m of the vibration system 20 of the damper 1 is increased, the natural frequency f of the dynamic damper 1 can be lowered (see FIG. 5).
According to the present invention, since only the small weight 9b is transferred in the case 2, the dimensions of the dynamic damper 1 are not changed.

  Next, the case where the exhaust collecting pipe of the large-sized low speed diesel engine is vibrated by the dynamic damper of the present invention will be described.

  FIG. 6 shows an upper portion of a large-sized low-speed diesel engine in a large-sized low-speed diesel power plant having a rated rotational speed of 100 to 200 rpm and an output number of several thousand kW to 50,000 kW. Is installed on a stand 50 provided on the large-sized low-speed diesel engine 30 on the exhaust side of the large-sized low-speed diesel engine 30. As shown in FIG. 8, the gantry 50 is provided in parallel with the crankshaft (not shown) of the large-sized low-speed diesel engine 30.

  The exhaust receiver 32 provided in the gantry 50 is common to many (for example, 8 to 12) cylinders 33a to 33l, and the pressure difference between the exhaust pulses discharged from the many cylinders 33a to 33l. Are to be equalized. The exhaust gas equalized by the exhaust receiver 32 is sent to the supercharger 34, and the supercharger 34 supplies fresh air to a scavenging receiver (not shown).

  As shown in FIG. 7, the supercharger 34 includes a gas inlet casing 35, a spiral casing 36, a silencer 37, and the like. The exhaust gas discharged from the supercharger 34 is sent through the duct 38 to the exhaust pipe 31 already described.

  As shown in FIGS. 7 and 8, the gantry 50 includes a rectangular top plate 51 on which the exhaust collecting pipe 31 of the large-sized low-speed diesel engine 30 is mounted, a number of columns 52 that support the top plate 51, It is formed by a first bracing 53 provided obliquely between the pillars 52 and a second bracing 54 provided diagonally between the large low-speed diesel engine 30 and the pillars 52.

  As shown in FIG. 8, the top plate 50 is formed in a rectangular shape, and a plurality of (for example, two) beams 55 parallel to the crankshaft of the large-sized low-speed diesel engine 30, and the crankshaft of the large-sized low-speed diesel engine 30. Are formed by a plurality of (for example, six) girders 56 in a direction orthogonal to each other, and a third bracing 57 provided obliquely between the beam 55 and the girders 56.

  As shown in FIGS. 6 to 8, the dynamic dampers 1 are provided horizontally at the front and rear ends of the top plate 51 of the gantry 50, that is, horizontally in the direction perpendicular to the crankshaft of the large-scale low-speed diesel engine 30, respectively. ing. More specifically, as shown in FIGS. 6 to 8, the dynamic damper 1 is connected to the outer end surfaces of the spar 56 at the front and rear ends of the top plate 51 of the gantry 50 in parallel with the spar 56 and a large low speed. It is provided in a direction orthogonal to the crankshaft of the diesel engine 30. As shown in FIG. 10, in the dynamic damper 1, the plate 25 is fixed to the beam 56 of the top plate 51 of the gantry 50 by welding.

  However, if the collective exhaust pipe 31 and the gantry 50 of the large-sized low-speed diesel engine 30 cause vibration of H type (the oscillating frame vibrates in the same phase in the vibration direction) or X type (the gantry vibrates in the opposite phase in the vibration direction). The case 2 and the guide bar 5 of the dynamic damper 1 vibrate in the direction orthogonal to the crankshaft of the large-sized low-speed diesel engine 30 together with the gantry 50, but the vibration is absorbed by the vibration system 20 of the dynamic damper 1. The H-type or X-type vibration of the exhaust collecting pipe 31 and the gantry 50 of the large-sized low-speed diesel engine 30 can be reduced.

It is sectional drawing of the dynamic damper which concerns on this invention. It is AA sectional drawing of FIG. This is a vibration model of a diesel engine. It is a fixed frequency change explanatory drawing of a dynamic damper. It is a fixed frequency change explanatory drawing of a dynamic damper. It is a front view of a dynamic damper. It is a side view of a dynamic damper. It is BB sectional drawing of FIG. It is an enlarged view of the part of the code | symbol D of FIG. It is EE sectional drawing of FIG. It is a side view of the conventional dynamic damper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dynamic damper 2 Case 3a, 3b Cover 5 Guide bar 7 Fastening tool 9a, 9b Weight 10 Spring

Claims (6)

A cylindrical case, a cover detachably provided at both ends of the case, a guide bar penetrating the cover and the case, a fastener provided detachably at both ends of the guide bar, and the guide bar A dynamic damper comprising a plurality of weights slidably provided in the case and a pair of springs in the case for urging the weights in an opposing direction. The dynamic damper according to claim 1, wherein a vibration system is constituted by the weight and the spring. The dynamic damper according to claim 1, wherein a hole for penetrating the guide bar is provided in the weight, and a slider is provided in the hole. 2. The dynamic damper according to claim 1, wherein a measuring pin in a lateral direction is provided in a spring guide adjacent to the weight, and a longitudinally elongated opening for projecting the measuring pin is provided in the case. The exhaust collecting pipe of the diesel engine is installed on a gantry provided in parallel with the crankshaft of the diesel engine, and the dynamic damper according to claim 1 intersects the crankshaft of the diesel engine at both front and rear ends of the gantry. Diesel engine characterized by being installed in the direction. The said base is formed by the rectangular top plate parallel to the crankshaft of the said diesel engine, and many support | pillars which support this top plate, And the dynamic damper of Claim 1 is provided in the front-and-rear both ends of the said top plate. The diesel engine according to claim 5, wherein the diesel engine is provided in a direction intersecting with a crankshaft of the diesel engine.

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