JPS5818554A - Cam-shaft - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camshaft for driving a fuel pump and for actuating valves in a reversible diesel engine, and more specifically, the camshaft is adapted to operate according to the direction of rotation of an engine crankshaft. Marine propulsion camshaft which is adapted to rotate in either direction and the fuel pump cam must be switched by a reversing device between a position for one direction of rotation and a position for the other direction of rotation. is connected with.

For example, from Swiss Patent Specification No. 552.133@, controlling fuel injection into a reversible internal combustion or diesel engine by means of a camshaft connected to and driven by the crankshaft. It has been known.

In a valve-type engine, the camshaft is the valve.

It has other cams mounted on itself, for example to control exhaust valves. The camshaft is of course reversed relative to the crankshaft to ensure that the fuel injection conditions are the same for both directions of rotation of the reversible engine. That is, when the direction of rotation of the engine is reversed, the camshaft is rotated by a certain angle relative to the crankshaft by the reversing device. Since the reversing device rotates the entire camshaft, the valve timing should not be completely satisfactory for reverse rotation;
The result is that the engine behaves quite imperfectly in the opposite direction of rotation.

It is therefore an object of the present invention to provide a camshaft in which the exhaust valve cam of the camshaft does not change its relative angular position with respect to the crankshaft despite reversal of the fuel injection cam. Thus, the cam adapted to operate the fuel pump according to the invention is mounted on the rotating camshaft, and the reversing device is adapted to rotate the fuel pump cam relative to the non-reversible camshaft. There is.

The camshaft according to the invention is not itself reversed, so that its relative phase with respect to the crankshaft is the same for both directions of rotation. the result,
The cams that operate the valves are rigidly fixed to the camshaft and remain in this constant phase position relative to the crankshaft in both directions of rotation, as in traditional methods, and the timing of the cams that operate the valves is therefore Optimal for either direction of engine rotation.

In the camshaft according to the invention, the reversing device acts only on the fuel pump cam which is rotatably mounted on the camshaft, and the fuel pump cam does not rotate as in the case of conventional integral camshafts. By means of the hydraulic pressure of the hydraulic reversing device for switching from one direction to another, it is rotated relative to the crankshaft and thus also, in the construction according to the invention, to the camshaft at a constant angle.

Also advantageously, the cam operating the fuel pump is rigidly fixed on a bushing for rotation relative to the camshaft. The advantage of this detail is that the cams for several separate fuel pumps can be adjusted individually.

The two cams or their bushes form a pair of annular pressure chambers of the hydraulic reversing device, which actuate a 2 m cylinder fuel pump as a simple and advantageous device for reversing the fuel injection cams, and such pressure The chambers are separated from each other by rings fixed to the camshaft with diametrically opposed joints.

The camshaft design of the present invention has the following advantages: optimum valve timing in both directions of engine rotation. That is, since the hydraulic chamber to which oil must be supplied is smaller, the volume of the hydraulic chamber can be reduced if the reversal time is short, or if the reversal time is designed to be the same. Also.

In contrast to conventional designs where the valve cam and fuel pump cam must be combined on one camshaft, the cam can be positively protruded. As a result, sufficient time is available during the descent of the fuel pump plunger to fill the pump chamber with fuel. The relatively heavy torque caused by fuel injection in known designs is transmitted mechanically by a cam or cam bushing that abuts the joint of a fixed ring on the cam or camshaft, so that it is transferred within the hydraulic reversing device. This must be ensured by the hydraulic action of the cam or cam bush.
This means that it is always connected to the joint regardless of the occurrence of torsional vibration within the shaft.

The invention will be described in more detail below with reference to one embodiment.

6- The pump casing 3 is mounted on a bracket 1 (FIG. 1) placed outside the diesel engine (not shown in detail) and held by screws 2. At the bottom of the pump casing 3 with the cover removed, the casing 3 drives two fuel pumps 6 and two suction pumps 7 for hydraulically operating the exhaust valves of the two engine cylinders. Insert the camshaft 4 into the receiver. Correspondingly, the camshaft 4 has one cam 8 for each associated cylinder, cams 8 arranged transversely oppositely to the vertical central plane; and controls an exhaust valve actuating plunger or piston 10 by a cam follower 9.

In the bottom of the pump casing 3 there is a camshaft bearing 11 placed behind the cam 8 when considered in the direction of its inward extension, behind which a cam bushing 12 according to the invention rests on the crankshaft 4. placed in rotation.

A fuel pump cam 13, which operates the fuel pump 6, is fixed to a reversible bushing 12 according to the invention, and a cam
It is connected to the pump by a follower 9 and a piston or plunger, the latter not shown.

Hydraulic reversing device 1 communicating between two fuel pump cams 13 with a hydraulic circuit (not shown) by pipes 15 and 16
4 is placed. The reversing device 14 is adapted to switch or reverse the two fuel pump cams 13.

Above the pump casing 3, to which the suction pump 7 is fixed directly and to which the fuel pump 6 is fixed by the intervention of an intermediate element 5, an adjusting or regulating spindle 17 is placed which extends horizontally parallel to the cam shaft 4; The amount of fuel discharged per stroke of the fuel pump 6 can be adjusted by this.

The fuel pump 6 is placed in a common fuel pump casing 18 from which a fuel line extends upwards to the injection pump, while a hydraulic line 20 connects the suction pump 7 to the exhaust valve operation. Connect to the servo motor.

As FIG. 2 shows, the camshaft 4 has a ring 21 in its center, ie inside the reversing device 14, which has wing-shaped joints 22 at two opposing points on the periphery. The ring 21 is later fixed to the camshaft 4 of FIG. 1 by contracting thereon and is firmly connected thereto, however, as shown in FIG. 3, a collar 23 made integral with the shaft 4' The collar 23 receives a joint 24 secured by a screw 25.

The cam bush 12 according to the invention, which is mounted for rotation on the cam shaft 4, rests on the ring 21 from both ends in the assembled state.

The bushing 12 also has diametrically opposed inwardly extending joints 26 through which the bushing 12 can be screwed together.
are combined with each other. As a result, there are two pressure fluid chambers 27 between the bushes 12, with the joint 22 of the ring 21 separating the two from each other. The pressure of the hydraulic fluid in the chamber 27 forces the joint 269- towards the joint 22 and against the ring 21 as there is an increase in pressure on one side and a decrease in pressure on the other side. Rotation of the relative bushings 12 is caused in a known manner, so that a reversal of the fuel pump cam 13, which is fixedly attached to the fuel pump bushing 12, occurs.

The threaded bush 12 and the chamber 27 are covered radially and outwardly by a sleeve 28, on which is placed an oil supply ring 29 which can be seen in FIG. Oil supply within 2 days of ring is from circular hole 3 in one direction of rotation.
0 into the annular groove 31 and from there the sleeve 28
through the circular hole 32 into one of the rooms 27. In the other direction of rotation, the oil flow path is through the circular hole 33, the groove 34 and the circular hole 35.

Oil leaking from chamber 27 and entering between camshaft 4 and bushing 12 provides lubrication between the two relatively moving parts.

The fuel pump cam 13 is externally secured to the bushings 12 (FIG. 1) 10- so as to be firmly connected to each bushing 12. Near the end the camshaft 4 has a bearing 11 that allows it to be rotatably mounted 2 Just outside there are two cams 8 fixed to the camshaft 4 , this cam 8 having two assist in operating the exhaust valve suction pump 7 (Figure 1).

[Brief explanation of the drawing]

FIG. 1 is a partial side view of a two-cycle diesel engine, showing the pump casing for the exhaust valves of the two cylinders of the engine, the camshaft with reverser, the fuel pump and the hydraulic pump. FIG. 2 shows a camshaft according to the invention, with overlapping and adjacent members shown separated from each other. and FIG. 3 is a view showing one variation of the details of the camshaft of FIG. 2. In fig. 3...Pump casing. 4...Camshaft. 7...Hydraulic pump. 8...Cam. 9... Cam Follower. 11...Cam shaft bearing. 12...Kam Butshu. 13...cam. 14... Reversing device. 21.23...Ring. 22.24...Joint part. 27...Pressure chamber agents Asagi and 4 people

Claims (1)

[Scope of Claims] (1) Drives a fuel pump and operates a reversible valve for a diesel engine, more specifically a valve for a diesel engine for marine propulsion, to control the direction of rotation of the engine crankshaft. It was made to rotate in every direction,
Fuel Pump Cam [60, 3° fuel pump on the cam shaft which needs to be able to be switched by a reversing device between one rotational position and the other rotational position. a cam adapted to be operated (mounted on a cam shaft for rotation), and a reversing device adapted to rotate said cam relative to the non-reversible cam shaft; Camshaft. (2. In the camshaft according to claim 1. The cam that drives the fuel pump is fixed on a bushing (12) configured to rotate relative to the camshaft. (3) The cam shaft according to claim 1. Two cams or cam bushes for operating a two-cylinder fuel pump include: forming a pair of annular pressure chambers of a hydraulic reversing machine, such chambers being characterized in that they have diametrically opposed joints and are separated from each other by rings fixed on the cam shaft; cam shaft.