JP2016094988A - Damper with dust cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve sealability to muddy water and dust, in a damper absorbing torsional vibration generated on a crank shaft, and provided with seal means for preventing intrusion of muddy water, dust and the like from the external.SOLUTION: A damper includes a hub 1 disposed outside of a crank case 2 of an internal combustion engine and fixed to a shaft end of a crank shaft, and a dust cover 14 disposed on the hub 1. The dust cover 14 is composed of an annular base portion 141 attached to the hub 1 in a close contact state, a bellows portion 142 extended from the annular base portion 141 to a crank case 2 side, and a sliding end portion 143 formed on an end portion at an opposite side of the annular base portion 141, of the bellows portion 142 and slidably closely kept into contact with an outer side face 22 of the crank case 2, and the bellows portion 142 is properly compressed between the annular base portion 141 and the sliding end portion 143.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a damper for absorbing torsional vibration generated in a crankshaft, which includes a dust cover for preventing intrusion of external muddy water, dust and the like.

  A torsional damper for absorbing torsional vibration generated in the crankshaft by resonance in a predetermined vibration frequency range is attached to an axial end of a crankshaft in an internal combustion engine of an automobile. As shown in FIG. 4, this type of torsional damper is disposed outside the crankcase 200 of the internal combustion engine, and a cylindrical boss portion 101 having an inner diameter is fixed to a shaft end of the crankshaft 400 by a bolt 401. An oil seal 300 is attached to the shaft hole inner peripheral surface 201 of the crankcase 200 for the purpose of preventing engine oil present in the machine (crank chamber) A from leaking to the outside. The oil seal 300 exhibits a sealing function against engine oil by having a main lip 301 facing the in-flight A side slidably in contact with the outer peripheral surface of the boss 101 of the hub 100 in the torsional damper ( For example, see Patent Document 1).

  However, in the case of the above-described structure, when muddy water, dust, etc. fly into the space B between the hub 100 and the crankcase 200, such dust, etc., is generated on the outer peripheral surface of the boss 101 of the hub 100 and the main part of the oil seal 300. By intervening in the sliding part with the lip 301, the sealing function against the engine oil may be impaired, or the main lip 301 may be worn out at an early stage.

  In order to prevent such intrusion of muddy water and dust from the outside, a rubber lip is attached to the hub 100 located outside the oil seal 300, and the rubber lip is slidably brought into close contact with the crankcase 200. It is known (see, for example, Patent Document 2). However, the rubber lip creates a gap in the sliding portion with the crankcase 200 due to an attachment error between the hub 100 and the crankcase 200, an axial displacement, and the like, and allows intrusion of muddy water, dust, and the like from the outside. There are concerns.

Japanese Patent Laid-Open No. 2002-276738 Japanese Utility Model Publication No. 59-180035

  The present invention has been made in view of the above points, and its technical problem is to prevent the entry of external muddy water, dust, and the like into a damper for absorbing torsional vibration generated in the crankshaft. In what is provided with a sealing means, it is in further improving the sealing performance with respect to muddy water and dust.

  As a means for effectively solving the above technical problem, a damper with a dust cover according to the invention of claim 1 is disposed outside the crankcase of the internal combustion engine and is fixed to the shaft end of the crankshaft. And a dust cover provided on the hub, the dust cover being attached to the hub in an intimate contact state, a bellows portion extending from the annular base portion toward the crankcase, and the annular base portion in the bellows portion Formed on the opposite end of the crankcase and slidably in contact with the outer surface of the crankcase, and the bellows portion is appropriately compressed between the annular base portion and the sliding end portion. Is.

  According to the above configuration, the dust cover provided in the hub of the damper is such that the sliding end portion is slidably in close contact with the outer surface of the crankcase by the extension force of the bellows portion against compression, Due to the elasticity, good followability with respect to axial mounting errors and axial displacement between the hub and the crankcase can be obtained. For this reason, it is possible to effectively prevent a gap from being generated due to an axial attachment error or an axial displacement between the crankcase and the sliding end of the dust cover.

  A damper with a dust cover according to a second aspect of the present invention is the configuration according to the first aspect, wherein the sliding end portion has a cylindrical shape extending in the axial direction.

  According to the above configuration, even if the sliding end portion of the dust cover is worn over time due to sliding with the crankcase, the diameter dimension and the radial width of the sliding surface are not changed. Sex is maintained.

  A damper with a dust cover according to a third aspect of the present invention is the configuration according to the first aspect, wherein the sliding end has a conical cylindrical shape opened to the outer diameter side.

  According to the above configuration, the sliding end of the dust cover has a conical cylindrical shape that opens to the outer diameter side, so that muddy water, dust, and the like can be more difficult to enter from the outer peripheral side.

  The damper with dust cover according to the present invention ensures good followability of the dust cover against mounting errors and axial displacement between the hub and the crankcase, thus improving the sealing performance against external muddy water and dust. Can be made.

It is principal part sectional drawing which cut | disconnects and shows 1st embodiment of the damper with a dust cover which concerns on this invention by the plane which passes along an axial center. It is principal part sectional drawing which cut | disconnects and shows the example which attached the garter spring in 1st embodiment of the damper with a dust cover which concerns on this invention by the plane which passes along an axial center. It is principal part sectional drawing which cut | disconnects and shows other embodiment of the damper with a dust cover which concerns on this invention by the plane which passes along an axial center. It is a fragmentary sectional view which cuts and shows an example of a damper with a dust cover concerning background art by a plane which passes along an axis.

  Hereinafter, preferred embodiments of a damper with a dust cover according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a first embodiment, wherein reference numeral 1 is a hub of a torsional damper, reference numeral 2 is a crankcase of an internal combustion engine, and reference numeral 3 is an inner periphery of a shaft hole 21 of the crankcase 2. An oil seal mounted on the surface, reference symbol A is in the machine (the crank chamber inside the crankcase 2). The torsional damper corresponds to the damper described in claim 1.

  The hub 1 of the torsional damper is disposed outside the crankcase 2, and a boss portion 11 projecting in a cylindrical shape from the inner diameter toward the in-machine A side has a shaft hole 21 formed in the crankcase 2. The disc shaft 12 has a disc portion 12 that is fastened to the shaft end of the crankshaft 4 located on the inner periphery of the crankshaft 4 by a bolt 41 and extends from the end of the boss portion 11 outside the machine. An annular protrusion 13 whose tip is opposed to the outer surface 22 of the crankcase 2 in the axial direction is formed concentrically with the boss portion 11.

  The torsional damper includes a hub 1, an annular mass body (not shown) concentrically arranged on the outer peripheral side thereof, and a rubber-like elastic material (rubber material or rubber-like material) that elastically connects the annular mass body and the hub 1. A non-illustrated annular rubber made of a synthetic resin material having elasticity), and the torsional direction resonance frequency (natural frequency) of the secondary vibration system made of the annular rubber and the annular mass is determined by the torsion of the crankshaft 4. The vibration frequency range where the amplitude is maximum is set.

  The oil seal 3 includes a metal ring 31, and an outer peripheral seal portion 32 made of a rubber-like elastic material that is provided on the outer peripheral surface of the metal ring 31 and press-fitted into the inner peripheral surface of the shaft hole 21 of the crankcase 2. A main lip 33 provided on the inner diameter portion of the metal ring 31 and extending toward the in-machine A side is provided, and the tip of the main lip 33 is in close contact with the outer peripheral surface of the boss portion 11 of the hub 1 of the torsional damper. In the example shown in FIG. 1, the main lip 33 is a springless lip with no garter spring on its outer peripheral surface. However, as in the example shown in FIG. Thus, a garter spring 34 for compensating for the tension of the main lip 33 may be attached.

  A dust cover 14 is provided on the hub 1 of the torsional damper. The dust cover 14 is made of a rubber-like elastic material. The dust cover 14 is attached in close contact with the outer peripheral surface of the annular protrusion 13 of the hub 1, and the annular base 141 is directed toward the crankcase 2. A bellows portion 142 in which a relatively large diameter crest portion and a relatively small diameter trough portion are alternately formed in the axial direction, and a crankcase formed at an end portion of the bellows portion 142 opposite to the annular base portion 141. 2 slidable end portions 143 slidably in close contact with the outer surface 22.

  The sliding end portion 143 of the dust cover 14 has a cylindrical shape extending in the axial direction, and the thickness in the radial direction is appropriately thicker than that of the bellows portion 142.

  When the torsional damper is not attached to the crankshaft 4, the axial length of the dust cover 14 is appropriately longer than the length in the attached state shown in FIG. 1 or FIG. In the mounted state shown in FIG. 2, the bellows portion 142 of the dust cover 14 is appropriately compressed in the axial direction, so that the sliding end portion 143 of the dust cover 14 is cranked by the extension force of the compressed bellows portion 142. The outer surface 22 of the case 2 is elastically pressed.

  The dust cover 14 can be attached to the outer peripheral surface of the annular protrusion 13 of the hub 1 by adhering the annular base portion 141 to the outer peripheral surface of the annular protrusion 13 of the hub 1, or the annular base portion 141 is a metal ring (not shown). As a structure joined to the peripheral surface, the annular base 141 is press-fitted on the outer peripheral surface of the annular protrusion 13 of the hub 1 or the annular base 141 is fastened to the outer peripheral surface of the annular protrusion 13 of the hub 1 with a metal band (not shown). One that is fixed or one that is integrally formed with the hub 1 is conceivable.

  In the damper with the dust cover configured as described above, the torsional damper is an annular rubber on the outer peripheral side of the hub 1 by being vibrated in the torsional direction in the vibration frequency region where the torsional amplitude of the crankshaft 4 is maximum. And a dynamic vibration absorption system comprising an annular mass resonates, and a torque due to the torsional direction vibration displacement is generated in a direction opposite to the torque due to the input vibration, thereby exhibiting a dynamic vibration absorption effect that reduces torsional vibration of the crankshaft 4. Is.

  In the oil seal 3, the outer peripheral seal portion 32 is closely fitted to the inner peripheral surface of the shaft hole 21 of the crankcase 2, and the tip of the main lip 33 slides on the outer peripheral surface of the boss portion 11 of the hub 1 in the torsional damper. By being in close contact with each other, the engine oil in the machine A is prevented from leaking from the shaft hole 21.

  The dust cover 14 provided on the annular protrusion 13 of the hub 1 has a sliding end 143 slidably in close contact with the outer surface 22 of the crankcase 2 by the extension force of the bellows 142 against axial compression. This prevents intrusion of muddy water, dust, and the like from the outer peripheral side.

  Since the dust cover 14 has good conformability with respect to the axial mounting error and axial displacement between the hub 1 and the crankcase 2 due to the stretchability of the bellows portion 142, the crankcase 2 and the sliding end portion can be obtained. It is possible to prevent a gap from being formed with 143 and realize excellent sealing performance against muddy water and dust. For this reason, muddy water, dust and the like are prevented from intervening in the sliding portion between the outer peripheral surface of the boss portion 11 of the hub 1 and the main lip 33 of the oil seal 3, and the sealing function of the oil seal 3 is maintained for a long period of time. can do.

  Further, since the sliding end portion 143 of the dust cover 14 has a cylindrical shape extending in the axial direction, even if the sliding end portion 143 wears with time due to sliding with the outer surface 22 of the crankcase 2, The radial dimension and the radial width of the sliding surface are unchanged, and a stable sealing property is maintained.

  In addition, the bellows portion 142 of the dust cover 14 easily expands and contracts, that is, the axial spring constant is small, and the pressing force against the sliding end portion 143 is small, so that the sliding resistance of the sliding end portion 143 can be kept small. Therefore, the power loss due to the dust cover 14 can be minimized.

  FIG. 3 shows another embodiment of the damper with a dust cover according to the present invention. The difference from the first embodiment described above is that the sliding end portion 143 of the dust cover 14 is changed. It is in the point formed so that the conical cylinder shape opened to the outer diameter side may be made.

  That is, according to this embodiment, the sliding end portion 143 of the dust cover 14 has a conical cylindrical lip shape opened to the outer diameter side, so that muddy water, dust, and the like are more difficult to enter from the outer peripheral side. can do.

  In the above-described embodiment, the hub 1 has been described as a hub of a torsional damper. However, for example, a structure in which a pulley for transmitting power to an auxiliary machine is connected via a coupling rubber is annular. The present invention can be similarly applied to a hub of a torque fluctuation absorbing damper (damper pulley) provided with a dynamic vibration absorbing system composed of rubber and an annular mass body.

1 Hub 13 Annular projection 14 Dust cover 141 Annular base 142 Bellows 143 Sliding end 2 Crankcase 3 Oil seal 4 Crankshaft A In-machine

Claims (3)

  A hub disposed outside the crankcase of the internal combustion engine and fixed to the shaft end of the crankshaft; and a dust cover provided on the hub, the dust cover including an annular base portion attached in close contact with the hub; A bellows portion extending from the annular base portion toward the crankcase side, and a sliding end portion formed on an end portion of the bellows portion opposite to the annular base portion so as to be slidably in contact with an outer surface of the crankcase A damper with a dust cover, wherein the bellows part is appropriately compressed between the annular base part and the sliding end part.   The damper with a dust cover according to claim 1, wherein the sliding end portion has a cylindrical shape extending in the axial direction.   The damper with a dust cover according to claim 1, wherein the sliding end portion has a conical cylinder shape opened to the outer diameter side.

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