JPS58138228A - Fitting method of timing belt - Google Patents

Abstract

PURPOSE:To facilitate the fitting of a timing belt by carving marks that the timing belt and pulleys are matched at a phase to stabilize a crank shaft, cam shaft and injection pump shaft independently in an engine interlocking these shafts and the belt. CONSTITUTION:The compression pressure is applied to a crank shaft 1 from the No.1 or No.2 cylinder through a connecting rod at the oblique line portion, and the shaft 1 is rotated and stabilized on the area with the bottom dead point serving as a center, an injection pump cam 9 is depressed by the spring force applied to a roller 11 corresponding to the bottom dead point and is stabilized at the portion with no oblique line, and a suction/discharge cam 8 is depressed by the spring force applied to a rocker arm 10 and is stabilized in the area with an asterisk but not in the area of high pressure as shown by oblique lines. Therefore, when individual pulleys 3, 6, 7 are engaged with the timing belt 2 so that marks M1-M4 are matched at the bottom dead point, no tension is applied to the belt 2 in the rotation direction. The belt and pulleys are carved so that the marks M1-M4 are matched at this position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a timing belt mounting system for engine drive timing in which the crankshaft, camshaft, and fuel injection pump shaft of an engine are interlocked by a timing belt and a pulley.

In order to adjust the engine drive timing, the tension belt between the pulley installed on the engine crankshaft and the pulley installed on the fuel intake pump shaft is tensioned between two tension pulleys 'C-. A system in which the rotational phase is made variable by
036) is known. However, with this method,
Skill is required to match the engine drive timing, and the necessary jigs are required, so adjustments can be made at locations such as automobile repair shops where IJ1 equipment is available to a certain extent and where skilled workers are available. , cannot be disassembled and reassembled.

Therefore, it is still common to use a timing belt and its pulley and tension the timing belt using only a normal tension pulley.

However, the problem with this method, as mentioned above, is that after removing the belt, it is difficult to set the assembly number so that the phases of each element are aligned when the belt is wound around the pulley again. Particularly, when installing in places such as agricultural equipment shops in the city where jigs are not provided, the engine drive timing cannot be accurately matched when disassembly and assembly are performed.

This invention was made based on the above circumstances, and has improved timing so that the timing belt can be wound around the same pulley so that accurate engine drive timing can be obtained without using a jig for installation. This is an attempt to provide a belt attachment method.

Hereinafter, the present invention will be specifically explained based on illustrated embodiments. In the figure, reference numeral 1 is a crankshaft, and a threaded pulley 3 around which a timing belt 2 is wound is attached here. Further, single pulleys 6 and 1 are attached to the intake/exhaust camshaft 4 and the fuel injection pump camshaft 5, respectively, and the timing belt 2 is also wound around these pulleys. Cams 8 and 9 are attached to the camshafts 4 and 5, respectively, and a rocker arm 10 is abutted on the cam 8, and an injection pump roller 11 is abutted on the cam 9, respectively. Further, in the figure, reference numeral 12 denotes a tensioner for tensioning the timing belt 2, and a tension roller 12a1 that comes into contact with the timing belt 2.
It includes an arm 12b and a tension spring 12c that support the roller. In this invention, the timing belt 2 and the pulleys 3, 6, and 1 are marked with alignment marks Ml 9Ml , , Ms , Ml
is marked. Above mark M1. The positions of Mz, Ms and Ml are set in the following relationship.

When the displacement of the piston, the displacement of the injection pump cam, and the displacement of the intake/exhaust cam are compared, the configuration is as shown in FIG. 2. The diesel engines used here are 4
It is a 360-degree crank cycle, and for the first and second cylinders at top dead center, the shaded portion on the piston displacement diagram indicates either intake or compression. Therefore, when considering the crankshaft 1, as shown on the piston displacement diagram, in the shaded area N001 or N0
Compression pressure is applied from the cylinder 92 via the funnel rod, and the crankshaft 1 is rotated back and forth around the bottom dead center to stabilize it. Further, the injection pump cam 9 is pressed by the swing force applied to the roller 11 corresponding to the bottom dead center position, and is stabilized at least in areas other than the shaded area. In addition, the intake/exhaust cam 8 is
Since it receives the pressing force of the spring applied to the rocker arm 10, it is stabilized not in the area of high pressure shown by diagonal lines, but in the area marked with * (in this area, the pressing force of the spring is the lowest). Therefore, at the bottom dead center, each pulley 3, 6 and 1 touches the timing belt 2 with its mark M1°Ml, Ms
, Ml are meshed with each other, no tension is applied to the timing belt 2 in the rotational direction. This timing matching position is indicated by [stock]. The timing belt 2 and pulleys 3.6 and 7 are stamped so that the marks M1, M1, Ms and M1 can be aligned at this position.

In this way, the timing belt 2 is connected to the pulleys 6 and 1.
Furthermore, when the timing belt 2 is attached to the pulley 3, an equal tension can be obtained on the timing belt 2 at each boot 93, 6, and 7, and the timing can be adjusted to the appropriate timing. In this case, there is no need to manually adjust the position as in the past, and when the engine is stopped, the timing is set automatically at a fixed position without applying any external rotational force, so there is no need for any jig. I don't.

Also, what can be seen in Fig. 3 is a comparison of the piston displacement, injection pump cam displacement, and intake/exhaust cam displacement in a three-cylinder diesel engine with a crank angle of 120 If. In the same way, if you search for the stable region of each element, you can find the position of the [phase] mark. Marks are placed on the timing belt 2 and the pulleys 3, 6, and 7 at this position, and with this alignment, the belt can be installed easily and at the right timing.

As described in detail above, the present invention relates to an engine in which the crankshaft of the engine and the fuel injection pump shaft are interlocked by a timing belt and the same pulley, in which the crankshaft, the camshaft, and the fuel injection pump shaft are each stabilized in each phase. Alignment marks are provided on the timing belt and the pulley so that the timing belt and the pulley are aligned, and the timing belt is attached to the pulley in alignment with the alignment mark. The pulleys and timing belts provided on each of the shafts, which are independently positioned corresponding to the points, are attached to the pulleys in a state where they are aligned with the alignment marks as a reference, and no jig is required for attachment.

Further, since the mark is used as a reference, the belt can be installed while visually confirming that the timing is correct, and even an unskilled worker can easily install the timing belt.

[Brief explanation of the drawing]

FIG. 1 is a side view of the main parts showing one embodiment of the present invention, and FIG.
The figure is a diagram showing a timing table for a two-cylinder diesel four-stroke engine, and FIG. 3 is a diagram for a three-cylinder four-stroke diesel engine in another embodiment. 1... Crankshaft, 2... Timing belt, 3...
...Pulley, 4,5...Camshaft, 6,1...Pulley.

Claims (1)

[Claims] In an engine in which the crankshaft, camshaft, and fuel injection pump shaft of an engine are linked by a timing belt and the same pulley, the timing belt and the pulley are connected in a phase in which the crankshaft, camshaft, and fuel injection pump shaft are each stabilized separately. A timing belt mounting method characterized in that an alignment mark is provided on the timing belt and the pulley so that the timing belt and the pulley are aligned, and the timing belt is attached to the pulley in alignment with the alignment mark.