JP3430659B2 - Diesel engine vacuum pump mounting structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a mounting structure of a vacuum pump which is one of auxiliary machines in a diesel engine.

[0002]

2. Description of the Related Art In a diesel engine, a negative pressure in the intake pipe cannot be obtained as in a gasoline engine. Therefore, in order to operate various negative pressure type actuators, a vacuum pump driven by engine output serves as an auxiliary machine. It is provided. For example, in the case of an automobile diesel engine, the negative pressure generated by the vacuum pump is supplied to the vacuum servo mechanism of the braking device. Conventionally, this vacuum pump is arranged coaxially with the drive shaft of an alternator, for example, and is configured to be driven by a crankshaft via a belt together with the alternator (for example, Japanese Patent Laid-Open No. 62-115963). See the bulletin). In this case, as a matter of course, the fuel injection pump is driven via another belt. There is also known a structure in which the cam shaft is coaxially arranged at the rear end portion and is directly driven by the cam shaft.

[0003]

However, in the latter configuration in which the vacuum pump is coaxially arranged on the camshaft, the rotational speed of the vacuum pump is restricted. That is, the engine speed becomes half the engine speed, which is not preferable in terms of securing the capacity.

Further, if the vacuum pump is configured to be driven from the crankshaft via the belt as in the former case, the degree of freedom of the pump rotation speed increases, but when the belt is damaged, the engine itself continues to operate. Nevertheless,
It is not preferable because negative pressure does not occur. In particular, there is a risk that negative pressure will not be supplied to the servo mechanism.

Therefore, if the vacuum pump is simultaneously driven by the timing belt for driving the fuel injection pump, the negative pressure will disappear and the engine will stop at the same time if the belt should be damaged. Although it is preferable from the point of view, in reality, the fuel injection pump is a very large auxiliary machine, so if a vacuum pump is arranged in parallel with this, the width dimension of the engine will increase and the length of the timing belt will increase. Is likely to be too long.

[0006]

Therefore, according to the present invention, a fuel injection pump is attached to a rear side surface of a cylinder block, and a pulley at a tip of a drive shaft of the injection pump, a pulley at a rear end of a cam shaft, and a tip of a drive shaft of a vacuum pump. And the pulleys are arranged on the same plane, and the same timing belt is wound around these pulleys to drive them integrally, and the pump main body of the vacuum pump is injected with the plane sandwiched. It is characterized in that it is placed on the opposite side of the pump.

According to a second aspect of the present invention, a plurality of projecting portions having a projecting length corresponding to a gap for accommodating the timing belt is provided on a plate-shaped bracket along the tip end surface of the injection pump supporting the fuel injection pump. Is provided, and the flange portion of the vacuum pump is supported at the tip of the protruding portion.

Further, in the third aspect, the projecting portion is formed of a shaft-shaped member having a screw portion screwed into the screw hole of the bracket.

Further, in claim 4, the pump body of the vacuum pump penetrates a belt cover for covering the timing belt and projects to the outside.

[0010]

[Function] Since the pump body of the vacuum pump and the fuel injection pump are located on the opposite sides of the timing belt, the layout as projected in the axial direction of the crankshaft is such that the two overlap each other, and the engine is that much. The external dimensions of are reduced.

According to the second aspect of the present invention, the flange portion of the vacuum pump is supported by the protruding portion in a state of being lifted from the bracket, and the timing belt passes through the gap therebetween.

In the third aspect of the invention, the protrusion is formed by screwing the shaft-shaped member into the bracket.

Further, in the structure of claim 4, the pump main body penetrating the belt cover is cooled by the outside air.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 3 show a diesel engine 1 having a vacuum pump mounting structure according to the present invention. The diesel engine 1 includes a cylinder block 2 in which a plurality of cylinders are arranged in series, and a cylinder head 3 mounted and fixed on an upper surface of the cylinder block 2.
And an oil pan 4 attached to the lower surface of the cylinder block 2. Reference numeral 5 is a crankshaft, a crank pulley 6 is attached to the front end thereof, and a flywheel 7 is attached to the rear end thereof.

A distribution type fuel injection pump 8 is attached to the rear side surface of the cylinder block 2 via a relatively large bracket 9. The bracket 9
Is, as shown in FIGS. 7 and 8, two plate-shaped portions 9a and 9b.
Are connected at an angle of about 90 °, and one plate-shaped portion 9a is fixed to the side surface of the cylinder block 2 with a plurality of bolts 10. In this mounted state, the other plate-shaped portion 9b is positioned along a plane orthogonal to the axial direction of the crankshaft 5, and the plate-shaped portion 9b has a front surface,
A flange portion 8a at the tip of the fuel injection pump 8 is fixed by a plurality of bolts 11. The drive shaft 12 of the fuel injection pump 8 penetrates the plate-shaped portion 9b and has a toothed pulley at the tip thereof.
Is fixed. As shown in FIG. 7, the plate-shaped portion 9b has a substantially triangular shape, and the fuel injection pump 8 is disposed below the plate-shaped portion 9b.

A cam pulley 14, which is also a toothed pulley, is fixed to the rear end of the cam shaft 32 protruding from the rear end surface of the cylinder head 3.
The injection pump pulley 13 and the injection pump pulley 13 are arranged on the same plane.

Further, as shown in FIGS. 4 to 6, three shaft-shaped members 15 are fixed to the rear surface of the plate-shaped portion 9b of the bracket 9, that is, the surface opposite to the mounting surface of the fuel injection pump 8. The vacuum pump 16 composed of a vane pump is fixedly supported by the shaft-shaped member 15 in a state of being lifted from the bracket 9. The drive shaft 17 of the vacuum pump 16 projects from the cylindrical pump body 16a supported by the shaft member 15 toward the front of the engine 1, that is, in the vicinity of the surface of the plate-shaped portion 9b. A vacuum pump pulley 18, which is also a toothed pulley, is fixed to the tip. This pulley 1
8 is arranged along the same plane as the cam pulley 14 and the injection pump pulley 13 described above. And
A common timing belt 19 is wound around these pulleys 18, 14 and 13, and the fuel injection pump 8 and the vacuum pump 1 are driven by the camshaft 32.
6 and 6 are driven at the same time. That is, the pump body 16a of the vacuum pump 16 is located on the opposite side of the fuel injection pump 8 with the plane in which the timing belt 19 continuous in an annular shape is located, and in the axial direction of the crankshaft 5 as shown in FIG. When projected along, the pump main bodies 16a are arranged at positions close to each other so as to overlap a part of the fuel injection pump 8. A tensioner pulley 20 that presses the timing belt 19 from the back side is provided between the vacuum pump pulley 18 and the cam pulley 14.

The above pulleys 13, 14, 18, 20 and the timing belt 19 are the belt cover front 2
The whole is covered with a belt cover composed of 1 and a belt cover rear 22. Here, a circular opening 23 is formed in the belt cover rear 22, and the pump main body 16 a of the vacuum pump 16 is formed in the opening 23.
Penetrates through and projects to the outside.

FIG. 9 is an exploded perspective view showing a detailed structure of the peripheral portion of the vacuum pump 16. The belt cover front 21 is attached to the plate-like portion 9b of the bracket 9 and the cylinder head 3 by a plurality of bolts 24. It is installed astride. Also, the belt cover front 21
The belt cover rear 22 and the belt cover rear 22 are joined together by a plurality of bolts 25 at their peripheral flange portions.

The pump body 16a of the vacuum pump 16
The shaft-shaped member 15 serving as a protruding portion that supports the screw has a screw portion 15a at its tip, and the screw portion 15a is adapted to be screwed into the screw hole 26 of the bracket 9, respectively. The belt cover front 21 is provided with small holes 27 through which the shaft-shaped members 15 pass. Further, of the three shaft-shaped members 15, the two shaft-shaped members 15A have a screw hole 28 in the seat portion at the tip thereof, and the pump main body 16a has a short bolt 29 screwed into the screw hole 28. The flange portion 16b of is fixed. Then, the remaining one shaft-shaped member 15B
Is a kind of stud bolt having a threaded portion 30 provided at the seat portion at the tip, and the flange portion 16b of the pump body 16a is similarly fixed by a nut 31 screwed therein. In this way, one shaft-shaped member 15B
Since the other two nuts 31 can be tightened while the small hole of the flange portion 16b is hooked, the workability is improved.

The flange portion 16b of the pump body 16a
Has a perfect circular shape, and the taper surface of the outer periphery thereof is in close contact with the opening 23 of the belt cover rear 22 from the inside through an unillustrated annular seal material or liquid gasket.

According to the configuration of the above embodiment, first, the fuel injection pump 8 and the vacuum pump 16 are integrally driven by the same timing belt 19, so that the vacuum pump 16 will be broken if the timing belt 19 is broken. In the case of stopping, the engine 1 itself is necessarily stopped, and it is possible to prevent a situation in which the servo mechanism of the braking device does not work while the vehicle is running. Since the vacuum pump 16 is driven by the belt, the ratio between the number of revolutions and the number of engine revolutions can naturally be set arbitrarily.

Further, although the fuel injection pump 8 is a relatively large auxiliary machine and the vacuum pump 16 is also a cylindrical one having a certain size as a vane pump, the pump main body 16a of the vacuum pump 16 is connected to the timing belt. By disposing it on the opposite side of the fuel injection pump 8 with 19 in between, it becomes possible to bring the two close to the position where they overlap each other on the crankshaft projection.
The size in the width direction of can be reduced. Further, by this, the timing belt 19 is shortened, and the belt cover 2
1 and 22 are also small.

Further, in the above embodiment, since the vacuum pump 16 is supported by the shaft-shaped member 15 that is screwed into the bracket 9, the shape and configuration itself of the bracket 9 are not complicated at all, and the bracket 9 is not complicated. Since 9 is also used as a member for supporting the fuel injection pump 8, the entire configuration is simplified. In particular, the shaft-shaped member 15 itself is screwed to the bracket 9 to form the protruding portion, which is advantageous in terms of the number of parts and the number of assembling steps. Instead of using such a shaft-shaped member 15, a boss-shaped protrusion may be formed on the bracket 9.

Further, since the pump body 16a of the vacuum pump 16 is projected from the belt cover rear 22 to the outside and is subjected to the cooling action by the outside air, the temperature rise due to its driving can be prevented, and the belt covers 21 and 2 can be prevented.
It is possible to avoid radiating heat into the inside.

[0027]

As is apparent from the above description, according to the vacuum pump mounting structure of the diesel engine of the present invention, the fuel injection pump and the vacuum pump are integrally driven by the same timing belt. In the unlikely event that the vacuum pump stops due to breakage of the timing belt and negative pressure is no longer generated, the engine itself will always stop, and the servo mechanism of the braking device will not work while the vehicle is running. Can prevent such a situation.

Since the pump main body of the vacuum pump is arranged on the opposite side of the fuel injection pump with the timing belt interposed therebetween, both can be brought close to a position where they overlap each other on the crankshaft projection. The size of the engine in the width direction can be reduced and the belt can be shortened.

Further, according to the invention of claim 2, since the vacuum pump is supported by the bracket for supporting the fuel injection pump, the whole structure is simplified.

According to the third aspect of the present invention, the shape and configuration of the bracket need not be complicated, and the shaft-shaped member itself is screwed to the bracket to form the protruding portion. It is advantageous in terms of assembly man-hours.

Further, according to the structure of claim 4, since the cooling effect is exerted by the outside air, it is possible to prevent the temperature rise due to the driving thereof.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration of a rear end portion of a diesel engine including a pump mounting structure according to the present invention.

FIG. 2 is a top view of the rear end portion of the diesel engine shown by cutting away the inside of the belt cover as seen from the direction of arrow A in FIG.

FIG. 3 is a side view of this diesel engine.

FIG. 4 is a front view corresponding to FIG. 1, showing a state in which a belt cover rear and some components are removed.

FIG. 5 is a top view corresponding to FIG. 2 with the same belt cover rear and some components removed.

FIG. 6 is a side view corresponding to FIG. 3, showing a state in which the same belt cover rear and some components are removed.

FIG. 7 is a front view corresponding to FIG. 1, showing only a fuel injection pump attached to a bracket.

FIG. 8 is a side view corresponding to FIG. 3, showing a state where only the fuel injection pump is attached to the same bracket.

FIG. 9 is an exploded perspective view of a main part of this embodiment.

[Explanation of symbols]

2 ... Cylinder block 8 ... Fuel injection pump 9 ... Bracket 13 ... Injection pump pulley 14 ... Cam pulley 15 ... Shaft member 16 ... Vacuum pump 18 ... Vacuum pump pulley 19 ... Timing belt

Claims (4)

(57) [Claims] 1. A fuel injection pump is attached to a rear side surface of a cylinder block, and a pulley at a tip of a drive shaft of the injection pump, a pulley at a rear end of a cam shaft, and a pulley at a tip of a drive shaft of a vacuum pump are arranged in the same plane. It is arranged such that the same timing belt is wound around these pulleys to drive them integrally, and the pump body of the vacuum pump is arranged on the opposite side of the fuel injection pump with the plane interposed. The diesel engine vacuum pump mounting structure. 2. A plurality of protrusions having a protrusion length corresponding to a gap for accommodating the timing belt is provided on a plate-like bracket which supports the fuel injection pump and extends along a front end surface of the injection pump. The vacuum pump mounting structure for a diesel engine according to claim 1, wherein a flange portion of the vacuum pump is supported at a tip thereof. 3. The vacuum pump mounting structure for a diesel engine according to claim 2, wherein the protruding portion is a shaft-shaped member having a screw portion that is screwed into a screw hole of the bracket. 4. A pump body of the vacuum pump,
The vacuum pump mounting structure for a diesel engine according to claim 1, wherein the vacuum pump mounting structure penetrates a belt cover that covers the timing belt and projects to the outside.