JP3913354B2 - Damper device for fuel injection pump power transmission system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a damper device for reducing torsional vibration generated in a power transmission system to a fuel injection pump.
[0002]
[Related background]
For example, Japanese Utility Model Laid-Open No. 6-73374 discloses a fuel injection pump driving device provided with this type of damper device. In this known fuel injection pump drive device, a coupling consisting of a flexible joint is inserted between the drive shaft and the pump shaft, and a damper having a dynamic vibration absorbing capacity is provided between the flexible joint and the pump shaft. It is assumed that the device is installed. Specifically, this damper device has a plurality of inertial bodies divided from each other, and one of these inertial bodies is an inertial body joint that connects the pump shaft and the coupling, and the other (one Alternatively, the two inertia bodies are connected to the inertia body joint via an elastic member. Therefore, according to this damper device, it is considered that each inertial body connected to the elastic joint can work as a dynamic vibration damper against torsional vibration generated in the fuel injection pump drive system.
[0003]
[Problems to be solved by the invention]
In general, a fuel injection pump is often disposed adjacent to a cylinder block of an internal combustion engine. For example, in the case of an internal combustion engine mounted on an automobile, the fuel injection pump is mounted on the outer surface of the cylinder block via a bracket. In this case, the outer diameter of the inertial body is limited to a size that does not interfere with the cylinder block, and accordingly, the magnitude of the inertia moment that can be secured in the inertial body is limited accordingly.
[0004]
It is recognized that the above-described known damper device exhibits desired dynamic vibration damping performance by setting the magnitude of the moment of inertia applied to each inertial body so that a predetermined relative relational expression is established. However, when the outer diameter of the inertial body is limited as described above, the moment of inertia can be set only within the limited range.
The present invention has been made based on the above-described circumstances, and its object is to provide a fuel injection pump power capable of ensuring a required moment of inertia without being limited to the outer diameter of the inertial body. An object of the present invention is to provide a transmission damper device.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a damper device for a fuel injection pump power transmission system according to claim 1 has a damper hub attached to the pump shaft of the fuel injection pump, and the damper hub has a pump shaft and a drive shaft at one end thereof. A flange for connecting to the coupling to be connected is formed to protrude radially outward. A ring-shaped inertial body is connected to the outer periphery of the damper hub via a rubber member. The inertial body has an inner diameter smaller than the outer diameter of the flange and an outer diameter larger than the outer diameter of the flange. . In addition, an extension projecting from the outer periphery of the inertia body in the axial direction of the pump shaft toward the combustion injection pump is provided, and this extension provides a seal portion for sealing the pump shaft projecting from the housing of the fuel injection pump. It has an annular shape that covers it from the outside while positioned inside .
[0006]
According to the damper device of the fuel injection pump power transmission system of the first aspect, since the inertia moment of the inertial body is increased by the above-described extension portion, the outer diameter allowed for the inertial body is reduced between the fuel injection pump, the cylinder block, The inertia moment of the inertial body can be set large even if it is limited based on the relative positional relationship between
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, the configuration of a power transmission system to a fuel injection pump to which the damper device of the embodiment is applied is schematically shown.
A fuel injection pump 1 shown in FIG. 1 is for an automobile diesel engine having a V-type cylinder layout, for example, and this fuel injection pump 1 is arranged inside a V bank in a cylinder block 2. In the engine fuel injection system according to this embodiment, a so-called common rail system is adopted. Therefore, the fuel injection pump 1 is a supply pump that supplies fuel to a not-shown animal pressure device (common rail). Yes.
[0008]
As is well known, the pump shaft 4 protrudes horizontally from the housing 6 of the fuel injection pump 1, and a cam is formed on the outer periphery of a portion facing the housing 6. The pump shaft 4 is rotatably supported in the housing 6 via a bearing (not shown). A bearing cover 8 as a seal portion for sealing the pump shaft 4 is attached to the outer surface of the housing 6 by bolt fastening.
[0009]
The drive shaft 10 is arranged in series with the pump shaft 4 and extends coaxially, and is connected to the crankshaft of the engine via a gear 12 fitted to the outer periphery of one end and an idler gear (not shown).
The pump shaft 4 and the drive shaft 10 described above are connected to each other via a laminate coupling 14, and the rotational power of the drive shaft 10 is transmitted to the pump shaft 4 via the laminate coupling 14. ing.
[0010]
Here, a cylindrical damper hub 16 is fitted to the outer periphery of the pump shaft 4, and the pump shaft 4 and the laminate coupling 14 are connected via the damper hub 16.
More specifically, the damper hub 16 is formed with a tapered hole portion 18 that opens to one end side toward the fuel injection pump 1 and extends to coincide with the outer peripheral surface of the pump shaft 4. The damper hub 16 is fitted to the pump shaft 4 through the tapered hole 18.
[0011]
On the other hand, a nut 20 is screwed onto the tip of the pump shaft 4 as shown in the figure. Therefore, a stepped hole 22 serving as a seating surface of the nut 20 is formed from the other end side of the damper hub 16, and the nut 20 is fastened to the pump shaft 4 in the tightened state shown in the drawing. ing. A key 21 is interposed between the damper hub 16 and the pump shaft 4.
[0012]
The damper hub 16 has a pair of flanges 24 protruding in the radial direction. FIG. 2 shows a front view of the damper hub 16 as seen from the axial direction of the pump shaft 4. As is apparent from FIG. 2, these flanges 24 are on the same straight line passing through the axis of the pump shaft 4. Has been placed. The flanges 24 are respectively formed with bolt holes 26, and the damper hub 16 and the laminate coupling 14 are bolted together by the flanges 24.
[0013]
An inertia ring 30 is connected to the outer periphery of the damper hub 16 via a rubber member 32. In this embodiment, a sleeve 34 is interposed between the rubber member 32 and the damper hub 16, and the inertia body ring 30 is fitted to the outer periphery of the damper hub 16 by this sleeve 34. The member 32 may be bonded to the damper hub 16.
[0014]
As shown in FIG. 1, an extension 36 that covers the bearing cover 8 of the fuel injection pump 1 is formed on the outer periphery of the inertia body ring 30. That is, in the inertia body ring 30, a circular recess is formed inside the extension 36 at one end face toward the fuel injection pump 1, and the bearing cover 8 is positioned in this recess in the illustrated assembled state. Yes.
[0015]
It should be noted here that, as shown in FIG. 2, the size of the outer diameter that can be secured in the inertia body ring 30 is limited based on the relative positional relationship between the fuel injection pump 1 and the cylinder block 2. Is a point. Specifically, an appropriate clearance is required between the outer peripheral surface of the inertia body ring 30 and the upper surface of the cylinder block 2 in order to avoid mutual interference. Further, in the case of the V-type engine as in this embodiment, a tool space is required between the power transmission system to the fuel injection pump 1 and the V bank so that good workability can be obtained. Therefore, the size of the outer diameter allowed for the inertial body ring 30 is limited to a range in which these necessary clearances and tool spaces can be secured.
[0016]
In the damper device of the above-described embodiment, the inertia moment of the inertia body ring 30 is increased by the extension portion 36. That is, the moment of inertia can be increased within the range of the outer diameter allowed for the inertia body ring 30. Therefore, the inertial ring 30 can be secured with a moment of inertia sufficient to exhibit the damping performance required for the damper device.
[0017]
Incidentally, FIG. 3 shows a reference example in which the extending portion 38 covering the flange 24 of the dust Npahabu 16 to the inertial body ring 30. Unlike the extension 36 that covers the bearing cover 8, this reference example is not included in the present invention, but the inertia moment of the inertia body ring 30 is increased by the extension 38 as in the extension 36. can do. Therefore, if the extension 38 is further formed in addition to the extension 36 in the inertia body ring 30, the moment of inertia can be further increased (this example is not shown).
[0018]
Referring to FIG. 4, the ratio of the natural frequency fd of the damper device to the natural frequency fe of the power transmission system comprising the pump shaft 4, the laminate coupling 14 and the drive shaft 10 and the resonance of torsional vibration generated in the power transmission system. The relationship with the rotational speed is shown.
In FIG. 4, the normal rotation speed of the power transmission system is in a region smaller than the predetermined rotation speed N ₁ . When the above natural frequency ratio is 0.9, the resonance speed of the power transmission system is a predetermined speed N _{1. If} the natural frequency ratio is set to 0.9 or more, the normal speed range is It is understood that no torsional vibration peak occurs in the power transmission system.
[0019]
As shown in FIG. 4, in the region where the natural frequency ratio exceeds 1.3, the resonance rotational speed increases from the predetermined rotational speed N ₂ , but the increase rate is substantially constant. The inventors of the present invention set 0.9 to 1.3 (0.9 ≦ fd / fe ≦ 1.3) as the optimum range as the setting range of the natural frequency ratio described above.
Furthermore, according to the inventors, as the rubber member 32 of the damper device, acrylonitrile-butadiene rubber (NBR) or NBR added with hydrogen (H-NBR) is used, and the loss factor is 0.25 to 0.25. It has been confirmed that a favorable vibration damping characteristic can be obtained by setting within the range of 0.35.
[0020]
Referring to FIG. 5, a curve representing the relationship between the rotational speed of the power transmission system and the driving torque at that time is shown. As shown by the solid line in the figure, when the damper device is not used, a peak occurs in the drive torque of the power transmission system in the normal rotation speed range. At the peak of such driving torque, excessive noise (gap noise) and gear pitching may occur in the gear train connected to the power transmission system. However, by using the damper device of the present invention, as indicated by a broken line in the figure, the rotational speed at which the peak of the driving torque occurs is shifted to a higher rotational side than the normal range. Furthermore, by providing the rubber member 32 with a high damping characteristic, the level of the driving torque is reduced as a whole.
[0021]
Damping performance as such damper device, by forming an extension 3 6 inertial body ring 30, is more effectively exhibited. That is, even if there is a limit on the outer diameter allowed for the inertia body ring 30, the moment of inertia can be further increased within the limit range, and accordingly, the characteristics of the damper device can be adjusted as desired. Capacity to do this. Further, since such an extension portion 36 is provided on the outer peripheral portion of the inertia body ring 30, the inertia moment per unit mass is larger than that of the inner peripheral portion, and this point is further effective.
[0022]
Moreover, the extension 3 power transmission system components due to the formation of the 6 (pump shaft 4 and laminate coupling 14, the drive shaft 10 and the bearing cover 8) since there is no impact on, extending the pump shaft 4, for example or There is no need to shorten the drive shaft 10. Therefore, a conventional member can be used as it is, and a damper device having excellent versatility can be obtained.
[0023]
Moreover, if the NBR material or the H-NBR material is used for the rubber member 32 like the Example mentioned above, high oil resistance can be ensured for the rubber member 32. In this case, it is advantageous not only in oil resistance when the fuel injection pump 1 is incorporated in an engine, but also in an airtight inspection when the fuel injection pump 1 is completed as a single product. That is, the airtight inspection of the fuel injection pump 1 as a product is performed by immersing the assembled fuel injection pump 1 in the oil. At this time, if the rubber member 32 is guaranteed to have high oil resistance, the pump Inspection is possible with the damper device mounted on the shaft 4. Therefore, it is not necessary to reattach the damper device after the inspection, and accordingly, the manufacturing process of the entire damper device can be shortened, which is very suitable as a damper device applied to an automobile engine.
[0024]
The present invention is not limited to the above-described embodiment shown in FIGS . In the embodiment, a pair of flanges 24 are formed on the damper hub 16, but such flanges may be formed in a disk shape. In this case, the flange is further provided with a clearance hole for a bolt that joins the coupling plate and the cross coupling.
[0025]
In addition , the present invention can be applied to a row type pump and a distribution type pump, and the cylinder layout of the engine is not limited to the V type.
[0026]
【The invention's effect】
As described above, according to the damper device of the fuel injection pump power transmission system of claim 1, the range of the outer diameter allowed for the inertial body without extending the power transmission system or deforming its constituent members. In addition, the moment of inertia can be further increased. Therefore, a torsional vibration of the power transmission system can be more effectively reduced, and a damper device having excellent versatility can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a fuel injection pump power transmission system to which a damper device of one embodiment is applied.
FIG. 2 is a front view of a damper hub and an inertia body ring as seen from the axial direction of the pump shaft in FIG.
FIG. 3 is a view showing an inertial body ring as a reference example .
FIG. 4 is a graph for explaining a relationship between a natural frequency ratio and a resonance rotational speed.
FIG. 5 is a graph for explaining a vibration damping effect by the damper device of the embodiment.
[Invention of code]
1 Fuel injection pump 4 Pump shaft 6 Housing 8 Bearing cover (seal part)
10 drive shaft 14 laminate coupling 16 damper hub 24 flange 30 inertial body ring 32 rubber member 3 6 extending length portion

Claims (1)

A coupling for mutually connecting a pump shaft protruding from the housing of the fuel injection pump and a drive shaft rotating in conjunction with the crankshaft of the internal combustion engine, and a seal portion mounted on the outer surface of the housing to seal the pump shaft Including a fuel injection pump power transmission system for transmitting rotational power from the drive shaft to the pump shaft,
A damper hub having a flange that is attached to the pump shaft and has a flange that projects radially outward from an outer periphery of the pump shaft and is coupled to the coupling;
A ring-shaped inertial body connected to the outer periphery of the damper hub via a rubber member and having an inner diameter smaller than the outer diameter of the flange;
The inertia body has an outer diameter larger than the outer diameters of the seal portion and the flange, and protrudes from the outer peripheral portion at one end on the seal portion side toward the seal portion in the axial direction of the pump shaft. A damper device for a fuel injection pump power transmission system, comprising an annular extension portion that covers the portion from the outside in a state in which the portion is positioned inside .

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