JP3599366B2 - Low vibration and low noise structure around the drive shaft of the fuel injection pump - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a low vibration and low noise structure around a drive shaft of a fuel injection pump in a diesel engine.
[0002]
[Prior art]
When a gear drive system is used to drive various accessories mounted on the engine, a timing gear for transmitting drive torque from a crankshaft to a camshaft, a fuel injection pump, etc. meshes with the timing gear case of the engine. It is arranged and housed in a state where it is not closed. Most large vehicles such as construction machines, buses and trucks are equipped with a diesel engine that generates a large amount of torque and has a low fuel cost. FIG. 5 is a cross-sectional view schematically showing the periphery of the fuel injection pump drive shaft of the vehicle diesel engine. The fuel injection pump drive gear 4 meshing with the crank gear via the intermediate gear is fitted to the front end of the fuel injection pump drive shaft 14. The drive shaft 14 is supported by two large and small ball bearings of a drive shaft case 15 attached to the timing gear case 2. On the other hand, an inertia weight (or automatic timer) 7 is fitted to a front end of a cam shaft of the fuel injection pump 10, and a rear end of the drive shaft 14 is connected to the inertia weight 7 via a coupling 6. The fuel injection pump 10 has a pump housing 10b other than the governor housing 10a mounted and fixed on a fuel injection pump bracket 16 attached to a cylinder block.
[0003]
[Problems to be solved by the invention]
In recent years, against the background of increasing the output of diesel engines and dealing with exhaust emissions, the pressure of fuel injection pumps has been increasing, and accordingly, the driven torque of the fuel injection pump has increased. Failure of the drive system caused by this, that is, damage to the coupling connecting the fuel injection pump drive shaft and the fuel injection pump, damage to the coupling mounting portion of the fuel injection pump drive shaft, damage to the fuel injection pump drive gear, or The occurrence of tooth pitting and the like and the increase in noise due to the increase in surface vibration of the timing gear case and the cylinder block due to the increase in the inter-tooth surface impact force applied to the fuel injection pump drive gear are coming to the surface.
[0004]
The causes of vibration and noise around the drive shaft of the fuel injection pump are due to the resonance between the drive shaft system of the fuel injection pump and the fuel injection pump system, and the misalignment of each component from the drive gear of the fuel injection pump to the fuel injection pump. It can be roughly divided into deviation. In the case of the resonance, an example of an order ratio analysis result of a stress waveform indicating a relationship between the resonance frequency and the engine forced frequency indicates that the natural frequency of the fuel injection pump drive shaft system is about the sixth order of engine rotation at around 200 Hz. Resonates with the forcing force, and the noise also increases. At this time, the drive shaft, coupling, and inertial weight (or automatic timer) of the fuel injection pump drive gear have large bending and torsional vibrations in the direction approaching the cylinder block side, and the amplitude of the coupling is large. It becomes the maximum in the part. Contrary to this, the combined vibration of bending and torsion of the fuel injection pump increases in the direction away from the cylinder block, and its amplitude becomes maximum at the rear end of the fuel injection pump.
[0005]
The cause of the increase in the coupled vibration is that the natural frequency of the fuel injection pump is close to the natural frequency of the portion formed by the inertial weight (or the automatic timer) and the cam shaft of the fuel injection pump. It is considered that the support rigidity of the fuel injection pump is low. Accordingly, the present invention focuses on the above-mentioned conventional problems, and raises the respective natural frequencies by improving the support method of the inertial weight (or the automatic timer) and increasing the support rigidity of the fuel injection pump, thereby increasing the fuel injection pump drive system. It is an object of the present invention to provide a low-vibration and low-noise structure around a drive shaft of a fuel injection pump that can prevent occurrence of a problem caused by resonance.
[0006]
[Means for Solving the Problems]
To achieve the above object, low vibration and low noise structure of a fuel injection pump driving system according to the present invention, in a low vibration and low noise structure around the fuel injection pump driving shaft of the diesel engine, the fuel injection pump, timing gear The fuel injection pump is disposed far from the drive gear of the fuel injection pump, and the fuel injection pump is mounted on a highly rigid crankcase portion with a fuel injection pump bracket,
Divide the fuel injection pump drive shaft into multiple parts,
An automatic timer or an inertial weight is provided between the fuel injection pump and the drive shaft of the fuel injection pump drive shaft divided into a plurality of drive shafts,
Providing a bearing base that supports the axially central portion of the drive shaft on the fuel injection pump side of the fuel injection pump drive shaft divided into a plurality,
Provided between the bearing base and the fuel injection pump drive gear, a coupling that connects the drive shaft on the drive side of the fuel injection pump drive shaft and the drive shaft on the fuel injection pump side divided into a plurality,
The bearing stand is disposed between the coupling and the automatic timer or inertial weight,
The bearing stand is provided on the fuel injection pump bracket. Further, the support of the bearing stand is characterized in that a fuel injection pump bracket for mounting a fuel injection pump is extended, and a bearing stand is attached to this extended portion. Also,
As the fuel injection pump with respect to the fuel injection pump bracket and horizontal positioning means of the bearing stand, a fuel injection pump bracket and a fuel injection pump, while providing an alignment structure consisting of a knock pin or an uneven engagement portion between the bearing stand,
A support is provided on the fuel injection pump bracket, and the support and the upper part of the fuel injection pump are connected by a roll prevention bracket.
Radiation noise was shielded by attaching a sound insulating cover covering the rotating part to the extension of the fuel injection pump bracket .
[0007]
[Action]
According to the above configuration, in the low-vibration / low-noise structure around the fuel injection pump drive shaft of the diesel engine, the fuel injection pump is disposed far from the fuel injection pump drive gear of the timing gear, and the fuel injection pump is mounted. A fuel injection pump bracket is attached to a highly rigid crankcase part, and the drive shaft of the fuel injection pump is divided into a plurality of parts. An automatic timer or an inertial weight is provided between them, and a bearing stand is provided for supporting the axially central portion of the drive shaft on the fuel injection pump side of the fuel injection pump drive shaft divided into a plurality, and the bearing stand and the fuel injection pump drive gear are provided. A coupling that connects the drive shaft on the drive side of the fuel injection pump drive shaft and the drive shaft on the fuel injection pump side divided into a plurality of parts. Only, the pedestal, the place between the coupling and the automatic timer or inertia weight, since the pedestal is provided to the fuel injection pump bracket, is possible to reduce the whirling of the automatic timer or inertia weight it can. In addition, since the bearing stand is supported by extending the fuel injection pump bracket on which the fuel injection pump is mounted and by attaching the bearing stand to this extension, alignment accuracy between the fuel injection pump and the bearing stand can be easily ensured. The horizontal positioning of the fuel injection pump and the bearing pedestal relative to the fuel injection pump bracket can be accurately and easily performed by an alignment structure including a knock pin or an uneven occlusal portion. In addition, since a support is provided on the fuel injection pump bracket and the support and the upper part of the fuel injection pump are connected by the anti-rolling bracket, the support rigidity of the fuel injection pump is increased, and the fuel injection pump is less likely to roll. Further, by attaching the sound insulation cover covering the rotating part to the extension portion of the fuel injection pump bracket, as well as shield the radiation noise as possible out to ensure the safety when the rotating part is damaged.
[0008]
【Example】
Hereinafter, an embodiment of a low vibration and low noise structure around a drive shaft of a fuel injection pump according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a schematic configuration around a drive shaft of a fuel injection pump, and FIG. 2 is a perspective view of a fuel injection pump bracket. The drive shaft of the fuel injection pump is divided into a plurality of front and rear parts, and the front drive shaft 1 is supported by two large and small ball bearings in a drive shaft case 3 attached to a timing gear case 2. A fuel injection pump drive gear 4 is fitted to the front end of the front drive shaft 1, and the fuel injection pump drive gear 4 is driven by a crank gear via an intermediate gear (not shown). The rear end of the front drive shaft 1 on the drive side and the front end of the rear drive shaft 5 on the fuel injection pump side are connected by a laminate cross coupling 6, and the rear drive shaft 5 is connected to a flange provided at the rear end by an inertial weight 7 Is connected to the inertial weight 7 by being fitted to the inertial weight 7. That is, the automatic timer or the inertial weight 7 is provided between the fuel injection pump 10 and the coupling. An intermediate portion of the rear drive shaft 5 is supported via a ball bearing on a bearing base 9 attached to the fuel injection pump bracket 8 with bolts 9a. This ball bearing is forcibly lubricated by lubricating oil guided from a fuel injection pump 10 or a cylinder block (not shown) to the bearing stand 9 through a pipe 11. The inertial weight 7 is fitted to the front end of the cam shaft of the fuel injection pump 10 as in the related art. The fuel injection pump bracket 8 is attached to a crankcase 20 of the engine with bolts 21. That is, the fuel injection pump 10 is mounted on the engine machine side with the fuel injection pump bracket 8.
[0009]
The length of the fuel injection pump bracket 8 in the axial direction of the drive shaft of the fuel injection pump is extended in the front-rear direction as compared with the conventional one, and the bearing base 9 is attached to an extended portion extending forward. The extension extending forward is provided between the automatic timer or the inertial weight 7 and the laminate cross coupling 6. The rear portion has a length up to the rear end of the governor housing 10a of the fuel injection pump 10, and a column 8a is provided on the left side of the rear end near the crankcase side wall. A trapezoidal projection 8 b is provided on the upper surface of the fuel injection pump bracket 8 along the axial direction, and the projection 8 b is provided on the bottom surface of the pump housing 10 b of the fuel injection pump 10 and the bottom surface of the bearing stand 9. By engaging with the groove, the fuel injection pump 10 and the bearing stand 9 are positioned in the horizontal direction. Therefore, the mounting hole for the fuel injection pump and the mounting hole for the bearing stand provided on the upper surface of the fuel injection pump bracket 8 may be simple holes. Note that the positioning of the fuel injection pump 10 and the bearing stand 9 in the horizontal direction may be performed using a knock pin without providing the projection 8b.
[0010]
FIG. 3 is a rear view of the fuel injection pump bracket to which the anti-rolling bracket is attached. As shown in FIG. 2, a screw hole 18 is provided on the rear surface of a support 8a provided at the rear end of the fuel injection pump bracket 8, and the screw hole 18 and the screw hole 18 provided on the end surface of the governor housing 10a of the fuel injection pump are used. An anti-rolling bracket 12 made of an inverted L-shaped plate is attached. In this manner, by fixing the upper portion of the governor housing 10a to the fuel injection pump bracket 8, it is possible to forcibly suppress the fuel injection pump from rolling. The fuel injection pump bracket 8 may be provided with two columns, and the upper portions of the pump housing and the governor housing may be fixed by anti-rolling brackets.
[0011]
FIG. 4 is an explanatory diagram of the sound insulating cover , and shows a cross-sectional portion of the inertial weight 7. The cross-sectional shape of the sound insulation cover 13 is an inverted U-shape, and is attached to the upper surface of the fuel injection pump bracket 8. The sound insulation cover 13 may be an integral type that simultaneously covers the inertial weight 7 and the laminate cross coupling, or may be a split type that separately covers the two. By covering the rotating part with the sound insulation cover 13, radiated noise generated from the rotating part can be cut off, and safety when the rotating part is damaged can be ensured.
[0012]
A new bearing stand 9 is provided to support both ends of the inertial weight 7 to suppress the whirling of the inertial weight 7, and to attach the anti-rolling bracket 12 to fix the upper part of the fuel injection pump 10 to inject fuel. Since the support rigidity of the pump 10 is improved and the natural frequency is increased, the structure around the drive shaft of the fuel injection pump is less likely to vibrate than in the related art, and noise is reduced. Further, since the rotating part is covered with the sound insulating cover, the noise is further reduced.
[0013]
【The invention's effect】
As described above, according to the present invention, a bearing stand is provided by extending the axial length of the fuel injection pump bracket, and the front of the automatic timer or the inertial weight of the fuel injection pump, which has been conventionally supported on one side, is provided on the bearing stand. The fuel injection pump has a structure that can easily secure the alignment accuracy between the fuel injection pump and the bearing base, so that the automatic timer or the inertia weight and the camshaft of the fuel injection pump are supported. And the coupled vibration of the bending and torsion of the drive shaft, coupling, automatic timer or inertia weight with respect to the fuel injection pump drive gear is significantly reduced. Further, since the support provided on the fuel injection pump bracket and the upper part of the fuel injection pump are connected by the anti-rolling bracket, the roll of the fuel injection pump is suppressed, and the support rigidity is increased. With this improvement, it is possible to prevent damage accidents around the drive shaft of the fuel injection pump and to reduce noise. Further, if a sound insulation cover for covering the rotating part is attached to the extension of the fuel injection pump bracket, noise can be further reduced, and safety in the event that the rotating part is broken can be ensured.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a schematic configuration around a drive shaft of a fuel injection pump.
FIG. 2 is a perspective view of a fuel injection pump bracket.
FIG. 3 is a rear view of the fuel injection pump bracket to which the anti-rolling bracket is attached.
FIG. 4 is an explanatory diagram of a sound insulation cover.
FIG. 5 is a cross-sectional view illustrating a schematic configuration around a drive shaft of a conventional fuel injection pump.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Front drive shaft 5 Rear drive shaft 7 Inertial weight 8, 16 Fuel injection pump bracket 8a Prop 8b Projection 9 Bearing base 10 Fuel injection pump 12 Roll prevention bracket 13 Sound insulation cover

Claims (5)

In the low vibration and low noise structure around the drive shaft of the fuel injection pump for diesel engines,
The fuel injection pump is disposed far from the fuel injection pump drive gear of the timing gear, and the fuel injection pump is mounted on a highly rigid crankcase portion with a fuel injection pump bracket,
Divide the fuel injection pump drive shaft into multiple parts,
An automatic timer or an inertial weight is provided between the fuel injection pump drive shaft and the fuel injection pump of the fuel injection pump drive shaft divided into a plurality,
Providing a bearing base that supports the axially central portion of the drive shaft on the fuel injection pump side of the fuel injection pump drive shaft divided into a plurality,
Provided between the bearing base and the fuel injection pump drive gear, a coupling that connects a drive shaft on the drive side of the fuel injection pump drive shaft divided into a plurality of parts and a drive shaft on the fuel injection pump side,
The bearing stand is disposed between the coupling and the automatic timer or inertial weight,
A low vibration and low noise structure around a fuel injection pump drive shaft, wherein the bearing stand is provided on the fuel injection pump bracket. 2. The low vibration and low noise around the drive shaft of the fuel injection pump according to claim 1, wherein the support of the bearing stand extends a fuel injection pump bracket for mounting a fuel injection pump, and the bearing stand is attached to the extension. Construction. As a means for horizontally positioning the fuel injection pump and the bearing pedestal with respect to the fuel injection pump bracket, an alignment structure comprising a knock pin or a concave and convex occlusal portion is provided between the fuel injection pump bracket and the fuel injection pump, the bearing pedestal. The low vibration and low noise structure around the drive shaft of the fuel injection pump according to claim 1 or 2. 3. A low-vibration and low-noise structure around a drive shaft of a fuel injection pump according to claim 1, wherein a support is provided on the fuel injection pump bracket, and the support is connected to an upper portion of the fuel injection pump by a roll-prevention bracket. . 3. Low vibration and low noise around the drive shaft of the fuel injection pump according to claim 1 or 2, wherein a noise insulation cover for covering a rotating portion is attached to an extension of the fuel injection pump bracket. Construction.

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