JP2651243B2 - Rotary drive of fuel injection pump in diesel engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary drive device in a diesel engine in which a distribution type fuel injection pump is driven to rotate via a gear train mechanism.

[Conventional technology]

Generally, as is well known, a distribution type fuel injection pump distributes fuel to fuel injection valves in each cylinder by reciprocating a pump plunger while rotating within a plunger barrel. Therefore, as compared with a so-called row type fuel injection pump in which the same number of pump plungers as cylinders in a diesel engine are arranged side by side, there are advantages such as smaller size and lighter weight and adaptability to high speed rotation.

[Problems to be solved by the invention]

However, on the other hand, the reciprocating motion of the pump plunger in this distribution type fuel injection pump is such that an end face cam plate having the same number of cams as the number of cylinders in the engine is provided on the end face of the pump plunger. This is performed by rotating the roller mounted on the side while being pressed by a spring. When the distribution type fuel injection pump is driven to rotate, the cam on the end face cam plate rides on the roller and the pump plunger advances. During the fuel delivery stroke in which fuel is delivered by movement, a large positive rotational torque acts as a load, while the cam on the end face cam plate is disengaged from the roller, and the pump plunger is retracted by a spring to take in fuel. During the suction stroke, the negative rotational torque acts as a load in the opposite direction, in other words, Since the rotational torque of the distribution type fuel injection pump fluctuates so as to reciprocate between positive and negative, the rotational torque is transmitted to the gear train mechanism for transmitting power from the crankshaft of the diesel engine to the distribution type combustion injection pump. In addition, the gear meshing noise is generated, and the durability of the gear train mechanism is reduced.

That is, when the distribution type fuel injection pump is rotationally driven via the gear train mechanism, the drive side gear of the gear train mechanism and the driven gear on the input shaft of the distribution type fuel injection pump, At both times when the rotational torque in the distribution type fuel injection pump fluctuates from positive to negative as described above and when fluctuates from negative to positive, the presence of the backlash causes the tooth surfaces to be separated once and then contacted again. Since such a phenomenon occurs repeatedly without interruption, there is a problem that considerably large backlash noise is generated and the durability of the gear is reduced.

The present invention focuses on the fact that a diesel engine requires a vacuum pump as a vacuum source and a lubricating oil pump for supplying lubricating oil to various working parts, and rotationally drives these vacuum pumps or lubricating oil pumps. It is an object of the present invention to solve the above-mentioned problem that occurs when the rotation of the crankshaft is transmitted to the distribution-type fuel injection pump through a gear train mechanism.

[Means for solving the problem]

In order to achieve this object, the present invention provides a diesel engine in which a distribution type fuel injection pump is rotationally driven by power transmission from a crankshaft through a gear train mechanism. The driven gear on the drive shaft of the distribution type fuel injection pump meshes with a power transmission gear to a vane type vacuum pump or a vane type lubricating oil pump, while the phase of the fuel intake stroke in the distribution type fuel injection pump is Further, the vacuum pump or the lubricating oil pump is configured so that the phases at which the rotational torques thereof are maximized substantially coincide with each other. "

[Action]

As described above, when the driven gear on the input shaft of the distribution type fuel injection pump meshes with the vane type vacuum pump or the power transmission gear to the vane type lubrication oil pump, the vacuum pump or lubrication oil pump Is driven by the power transmission from the type fuel injection pump, the rotational torque required to rotationally drive the vacuum pump or the lubricating oil pump is added to the rotational torque for rotationally driving the distribution type fuel injection pump. Will be done.

In this case, in the vane-type pump, a plurality of vanes provided on the rotor that rotates eccentrically in the casing are protruded and retracted from the outer peripheral surface of the rotor with the rotation of the rotor, and the rotor and the casing are separated from each other. By utilizing the fact that the gap volume between them increases and decreases, the suction and discharge of the fluid are repeatedly performed, so that the rotational torque when the vane type pump is rotationally driven is increased during one rotation of the rotor. It fluctuates in a wave-like manner as it repeatedly rises and falls.

Therefore, the driven gear on the input shaft of the distribution type fuel injection pump is meshed with the power transmission gear to the vane type vacuum pump or the vane type lubricating oil pump, and this vacuum pump or lubricating oil pump is As described above, when the rotary drive is performed by power transmission from the injection pump, the phase of the fuel suction stroke in the distribution type fuel injection pump substantially coincides with the phase in which the rotational torque of the vacuum pump or the lubricating oil pump is maximized. With this configuration, among the rotational torque at the time of power transmission from the crankshaft to the distribution type fuel injection pump, the negative rotation torque during the fuel suction stroke of the distribution type fuel injection pump includes the vane type vacuum. Since the maximum value of the rotational torque for rotationally driving the pump or the vane type lubricating oil pump is added, the Rotational torque at the time of the fuel intake stroke type fuel injection pump can be prevented from fall to a negative value.

As a result, when the power is transmitted from the drive gear on the crankshaft side to the driven gear in the distribution type fuel injection pump, a state is always transmitted in which a positive rotational torque is transmitted. It is possible to reliably avoid the occurrence of the phenomenon that the tooth surfaces repeatedly contact and then come into contact again due to the backlash between the driven gear and the driven gear on the input shaft of the fuel injection pump.

〔The invention's effect〕

Therefore, according to the present invention, a problem that occurs when a distribution type fuel injection pump in a diesel engine is rotationally driven by gear transmission from a crankshaft, that is, an increase in gear backlash noise and durability of a gear train mechanism. The use of rotating a vacuum pump or a lubricating oil pump required in a diesel engine can be used to reliably prevent the reduction without complicating the structure and increasing the cost.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a diesel engine having four cylinders, reference numeral 2 denotes a distribution type fuel injection pump for the diesel engine 1, and reference numeral 3 denotes The camshaft in the diesel engine 1 is shown.

A drive gear 5 is provided on a crankshaft 4 of the diesel engine 1, and a drive shaft 2 b of the distribution type fuel injection pump 2 and a driven shaft having a diameter twice the diameter of the drive gear 5 are provided on the camshaft 3. Gears 6, 7 are fitted respectively, and an idle gear 8 meshing with each of the gears 5, 6, 7 is disposed in a portion between the gears 5, 6, 7, and the crankshaft. 4 is transmitted to the drive shaft 2b and the camshaft 3 of the distribution type fuel injection pump 2 at a reduced speed by half. The gears 5, 6, 7, 8 are:
It is covered by a gear case 9.

As shown in FIG. 2, the distribution type fuel injection pump 2 includes a main body case 2a, a drive shaft 2b, a plunger barrel 2c, a pump plunger 2d, and the like. The pump plunger 2d has the diesel engine 1 An end cam plate 2f having the same number of cams 2e as the cylinders in the above is provided, and the end cam plate 2f is pressed and urged by a spring 2h against a roller 2g mounted on the main body case 2a, while the pump plunger 2d is provided. Is connected to the drive shaft 2b via a slidable coupling 2i, and is configured to reciprocate while rotating in the plunger barrel 2c by rotation of the drive shaft 2b. Thereby, the fuel is distributed to the fuel injection valves in each cylinder of the diesel engine 1 and sent out.

Reference numeral 10 denotes a vane-type vacuum pump attached to the gear case 9. The vacuum pump 10 is eccentric to the inside of the casing 10a, as shown in FIGS. 3 and 4. And a drive shaft 10c for rotating the rotor 10b in the direction of arrow A.
Has three vanes 10d.

A gear 11 having 3/8 of the number of teeth of the driven gear 6 of the drive shaft 2b of the distribution type fuel injection pump 2 is fitted to a drive shaft 10c of the vacuum pump 10, and the gear 1
1 is a driven gear 6 in the distribution type fuel injection pump 2
, The vacuum pump 10 is configured to be rotationally driven by power transmission from the distribution type fuel injection pump 2.

With this configuration, the distribution type fuel injection pump 2
The rotational torque required to rotationally drive the vane-type vacuum pump 10 is added to the rotational torque for rotationally driving the vacuum pump 10 by the power transmission from the crankshaft 4.

In this case, the rotational torque for rotationally driving the distribution type fuel injection pump 2 is such that the cam 2e on the end face cam plate 2f rides on the roller 2g and the pump plunger 2d as shown by a chain line B in FIG. During the fuel delivery stroke in which fuel is delivered by forward movement, the value becomes a positive value, the cam 2e in the end face cam plate 2f is disengaged from the roller 2g, and the pump plunger 2d is moved backward by the spring 2h to take in fuel. At the time of the fuel suction stroke, the vane type vacuum pump 10 fluctuates so as to reciprocate between positive and negative so as to take a negative value.
The three vanes 10d provided on the rotor 10b, which rotates eccentrically in a, are rotated by the rotation of the rotor 10b.
Of the suction port 10 utilizing the fact that the space between the rotor 10b and the casing 10a
Since the suction is performed from the outlet f and then the discharge is performed from the discharge port 10e, the rotational torque when the vane-type vacuum pump is rotationally driven may increase or decrease during one rotation of the rotor 10b. Is repeated three times.

In this case, the rotation of the crankshaft 4 is transmitted to the vacuum pump 10 once at a reduced speed of 1/2 to the distribution type fuel injection pump 2 and then at an increased speed of 8/3. As a result, the rotational torque of the vacuum pump 11 becomes
As shown by a dotted line C in the figure, the waveform fluctuates.

Therefore, the drive shaft 10 of the vane type vacuum pump 10
When the gear 11 fitted to c is engaged with the driven gear 6 fitted to the drive shaft 2b of the distribution type fuel injection pump 2, the phase of the fuel intake stroke in the distribution type fuel injection pump 2 In the vane-type vacuum pump 10, the phase at which the rotational torque is maximized during one rotation of the rotor 10b is set so as to substantially match.

Then, the vane-type vacuum pump 10 is provided with a negative rotation torque during the fuel suction stroke of the distribution-type fuel injection pump 2 among the rotation torques at the time of power transmission from the crankshaft 4 to the distribution-type fuel injection pump 2. The maximum value among the rotational torques for rotational driving is added, and the rotational torque when the rotational torque in the distribution type fuel injection pump 2 and the rotational torque in the vane type vacuum pump 10 are combined is the fifth. As shown by the solid line D in the figure, the rotational torque during the fuel suction stroke of the distribution type fuel injection pump 2 can be prevented from falling to a negative value.

As a result, when power is transmitted from the drive gear 5 of the crankshaft 4 to the driven gear 6 of the distribution type fuel injection pump 2 via the idle gear 8, a state in which positive rotational torque is always transmitted is established. It is possible to avoid the occurrence of a phenomenon that the tooth surfaces repeat and then come into contact again with each other due to the backlash between the driven gear 6 and the backlash.

In the above-described embodiment, the case where the vane-type vacuum pump 10 is driven to rotate is shown. However, the present invention is not limited to this, and can be applied to the case where the vane-type lubricating oil pump is driven to rotate. Needless to say.

[Brief description of the drawings]

1 is a front view, FIG. 2 is an enlarged sectional view taken along line II-II of FIG. 1, and FIG. 3 is III of FIG.
FIG. 4 is an enlarged sectional view taken along line III-III, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 1 ... diesel engine, 2 ... distribution type fuel injection pump,
2b …… Drive shaft in distribution type fuel injection pump, 3…
... Cam shaft, 4 ... Crank shaft, 5 ... Drive gear, 6 ...
Driven gear, 8 idle gear, 10 vane-type vacuum pump, 10c drive shaft of vane-type vacuum pump, 11 gear.

Claims (1)

(57) [Claims] 1. A diesel engine in which a distribution type fuel injection pump is rotationally driven by power transmission from a crankshaft via a gear train mechanism, wherein the distribution type fuel injection pump is included in each gear in the gear train mechanism. While a driven gear on the drive shaft of the injection pump meshes with a power transmission gear to a vane-type vacuum pump or a vane-type lubricating oil pump, the distribution-type fuel injection pump uses the vacuum pump or A rotary drive device for a fuel injection pump in a diesel engine, wherein a phase at which a rotational torque of a lubricating oil pump is maximized substantially coincides.