JP2013119783A - Method of tightening bolt of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of tightening a bolt of an internal combustion engine, the method capable of simultaneously and evenly tightening a plurality of bolts, easily confirming whether hydraulic pressure normally acts on all hydraulic jacks and preventing an accident due to insufficient tightening torque of the bolts.SOLUTION: A plurality of hydraulic jacks 1 are connected in series by using hydraulic hoses 6 and, at the same time, the hydraulic jack 7 of one end and a hydraulic pump 5 are connected by a hydraulic hose 8. The hydraulic pressure of oil in the hydraulic hose 8 located on the hydraulic pump 5 side of the hydraulic jack 7 of one end and the hydraulic pressure of oil in a hydraulic hose 9 located on the side opposite to the hydraulic jack 7 side of the one end of a hydraulic jack 14 of the other end are measured and, when two hydraulic pressures are different, it is determined that either hydraulic jack is abnormal.

Description

  The present invention relates to a bolt tightening method for an internal combustion engine.

  Conventionally, as a bolt tightening method for an internal combustion engine, there is a tightening using hydraulic pressure described in Japanese Utility Model Laid-Open No. 3-120380 (Patent Document 1). In this internal combustion engine bolt tightening method, the bolt is tightened by pulling the bolt with a hydraulic jack and tightening the nut to the seating surface in a state where a tensile load is applied to the bolt. The bolt tightening method of the internal combustion engine is less affected by the friction of the seating surface and the screw part than the general tightening method of tightening with torque, and the axial force management of the bolt can be reliably performed and Tightening that does not cause bending or torsional stress can be realized.

  FIG. 3 is a diagram for explaining a conventional method of tightening a plurality of bolts using hydraulic pressure.

  In this method, the hydraulic pump 100 and the joint 101 are connected by the hydraulic hose 103, and the hydraulic jack 105 is installed on each bolt, and then the joint 101 and each hydraulic jack 105 are connected by the hydraulic hose 106. Then, the oil from the hydraulic pump 100 is distributed to each hydraulic jack 105 via the joint 101, and each bolt is tightened using the oil pressure of the oil distributed to each hydraulic jack 105. . According to this bolt tightening method, there is no influence of friction between the nut, the seating surface and the threaded portion, and no bending or torsional stress is generated on the bolt, and a plurality of bolts can be tightened simultaneously and uniformly.

  However, according to the conventional bolt tightening method, there is a problem that even if some of the plurality of hydraulic jacks have a hydraulic failure, it is not known. If some of the plurality of hydraulic jacks have a hydraulic problem, there is a risk that an insufficient bolt tightening torque may occur, leading to an accident. Also, when an accident occurs, it is indispensable to identify the abnormality of each hydraulic jack, but there is a problem that it takes a lot of time and labor to identify the location and cause of the abnormal hydraulic jack.

Japanese Utility Model Publication No. 3-120380

  Therefore, the problem of the present invention is that a plurality of bolts can be tightened simultaneously and uniformly, and it can be easily confirmed whether the hydraulic pressure is working normally on all the hydraulic jacks. An object of the present invention is to provide a bolt tightening method for an internal combustion engine that can be prevented.

In order to solve the above-described problem, a bolt tightening method for an internal combustion engine of the present invention includes:
Installing a hydraulic jack having two connection ports for supplying and discharging oil to each bolt of the internal combustion engine having a plurality of bolts;
Connecting a plurality of the hydraulic jacks in series with a hydraulic hose while connecting a hydraulic jack at one end of the plurality of hydraulic jacks connected in series with a hydraulic pump with a hydraulic hose;
Applying hydraulic pressure of the hydraulic jack at a specified value;
Measuring the oil pressure on the hydraulic pump side of the hydraulic jack on the one end and the oil pressure on the opposite side of the hydraulic jack on the one end of the hydraulic jack on the other end of the plurality of hydraulic jacks; And a step of fastening the plurality of bolts and nuts after confirming that the hydraulic pressures at both ends are the same.

  According to the present invention, the hydraulic pump and the plurality of hydraulic jacks are connected in series with the hydraulic hose in a state where the hydraulic pump is arranged at one end, and the hydraulic pressures at two locations on both sides of the plurality of hydraulic jacks are sandwiched. Since the measurement is performed, it is possible to confirm that there is an abnormality in any one of the plurality of hydraulic jacks only by measuring the difference between the hydraulic pressures at two locations on both sides. In other words, when the hydraulic pressures at the two locations on both sides are the same, it is possible to determine whether all the hydraulic jacks are normal and that they are correctly installed on the bolts. Abnormality or abnormal installation of any hydraulic jack to the cylinder head bolt can be determined. Therefore, it is possible to prevent the bolt from being tightened when the hydraulic jack is in an abnormal state, and there is no shortage of bolt tightening torque, and an accident based on the shortage of bolt tightening torque does not occur.

  According to the bolt tightening method for an internal combustion engine of the present invention, it is possible to prevent the bolt from being tightened when the hydraulic jack is abnormal, and there is no shortage of bolt tightening torque. Accidents based on shortages will not occur.

It is a figure when the cylinder head in the middle of performing the bolting method of the cylinder head bolt of the internal combustion engine which is one Embodiment of the bolt fastening method of the internal combustion engine of this invention is seen from upper direction. It is a figure which shows the hydraulic jack installed in the cylinder head bolt in detail. It is a figure explaining the fastening method of the several volt | bolt using the conventional oil_pressure | hydraulic.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a view of a cylinder head during tightening of a cylinder head bolt and a nut of an internal combustion engine, which is an embodiment of a bolt tightening method for an internal combustion engine of the present invention, as viewed from above. . Hereinafter, a method of fastening four cylinder head bolts and nuts will be described with reference to FIG.

  First, a hydraulic jack 1 having two hydraulic couplers 10 as connection ports for supplying and discharging oil is installed on each cylinder head bolt (this process will be described in detail later).

  Thereafter, as shown in FIG. 1, four hydraulic jacks 1 are connected in series by three hydraulic hoses 6, a hydraulic jack 7 at one end of the four hydraulic jacks 1 connected in series, and a hydraulic pump 5. Are connected by a hydraulic hose 8.

  Next, a pressure gauge 21 in which a high pressure hose 9 and an air vent plug 22 are joined is connected to the other hydraulic coupler 10 of the fourth hydraulic jack 1.

  The hydraulic pump 5 has a pressure gauge 11, and the oil pressure of the oil supplied from the hydraulic pump 5 to the hydraulic hose 8 is measured by the pressure gauge 11.

  FIG. 2 is a diagram showing in detail the hydraulic jack 1 installed on the cylinder head bolt 31.

  As shown in FIG. 2, the hydraulic jack 1 is used to tighten a cylinder head bolt 31 that is tightened to a cylinder head 30 of an internal combustion engine. The hydraulic jack 1 includes a hydraulic piston 58, a hydraulic cylinder 59, two hydraulic couplers 10, 10, a jack stand 88, and a jack handle 56.

  The hydraulic piston 58 is internally threaded with an internal thread adapted to the male thread of the cylinder head bolt 31. The hydraulic cylinder 59 is disposed so as to surround the outside of the hydraulic piston 58, and the hydraulic piston 58 is movable in the axial direction with respect to the hydraulic cylinder 59.

  Further, each of the hydraulic piston 58 and the hydraulic cylinder 59 has an axially opposed surface, and the hydraulic piston 58 and the hydraulic cylinder 59 have an outer periphery, an inner periphery of the hydraulic cylinder 59, and upper and lower opposing surfaces. A chamber 86 is formed.

  The hydraulic piston 58 has a hole 85 for connecting the hydraulic coupler 10 on the upper surface thereof, and communicates with the hydraulic chamber 86.

  The jack stand 88 is in contact with the lower surface of the hydraulic cylinder 59 and surrounds the outside of the round nut 55 (so as not to contact). The jack stand 88 has a long hole 89 (long in the circumferential direction) through which the handle 56 passes.

  A procedure for tightening the cylinder head bolt 31 and the nut 55 will be described. First, the round nut 55 is screwed into the cylinder head bolt 31 by hand. (The state of the bolt and nut on the right side of FIG. 2)

  Next, the jack stand 88 is placed so as to surround the outside of the round nut 55. Then, the hydraulic piston 58 is screwed into the cylinder head bottle 31 in a state where the hydraulic piston 58, the hydraulic cylinder 59, and the hydraulic coupler 10 are combined. When the cylinder head 30, the jack stand 88, and the hydraulic cylinder 59 are in close contact, a hydraulic hose is connected.

  The air vent plug 22 is opened and the lever of the hydraulic pump 5 is operated to fill the oil from the hydraulic pump 5 including the hydraulic chamber 86 to the pressure gauge 21 at the other end. Then, the air vent plug 22 is closed and the lever of the hydraulic pump 5 is operated to increase the hydraulic pressure to a specified value.

  At this time, in the hydraulic chamber 86, the hydraulic pressure acts on the surfaces facing the hydraulic piston 58 and the hydraulic cylinder 59, so that the hydraulic piston 58 is pushed up with respect to the hydraulic cylinder 59. That is, the cylinder head bolt 31 is pulled up by the hydraulic piston 58 with respect to the cylinder head 30 with a predetermined hydraulic pressure.

  Then, in a state where the cylinder head bolt 31 is pulled up, the jack nut 56 is used to tighten the round nut 55 until it is not advanced. Thereafter, when the hydraulic pressure from the hydraulic pump 5 is withdrawn, the cylinder head bolt 31 and the round nut 55 are tightened with a predetermined hydraulic pressure.

  Since the four cylinder head bolts 31 and the round nut 55 in the cylinder head 30 must be uniformly tightened with the same torque, it is necessary to perform the above operation at the same time at four locations. Become.

  At this time, if the hydraulic jack 1 is normal, the oil pressure in the left and right hydraulic couplers 10 and the oil pressure in the hydraulic chamber 86 become the same oil pressure. If normal, the measured value of the pressure gauge 11 and the measured value of the pressure gauge 21 are the same.

  As shown in FIG. 1, after connecting the hydraulic pump 5 having the pressure gauge 11, the four hydraulic jacks 1 and the pressure gauge 21 in series, the measured value of the pressure gauge 11 and the measured value of the pressure gauge 21 are the same. In the case of the above, it is judged that all the connections are normal, all the hydraulic jacks 1 are normal, and the cylinder head bolts 31 are normally installed, while the pressure gauge 11 and the pressure gauge 21 are measured. Are different from each other, it is determined whether any connection abnormality, any hydraulic jack 1 abnormality, or any hydraulic jack 1 installation abnormality to the cylinder head bolt 31 is detected.

  Specifically, since the hydraulic jacks 1 are connected in series, if the oil pressure is not transmitted due to a foreign matter biting into one hydraulic jack 1, the oil pressures on both sides of the hydraulic jack 1 are different. Therefore, the pressure values of the pressure gauge 11 and the pressure gauge 21 are different. Therefore, by measuring the difference in hydraulic pressure between the pressure gauge 11 on one side of the four hydraulic jacks 1 connected in series and the pressure gauge 21 on the other side, an abnormality of at least one hydraulic jack 1 can be determined. When the measured pressure values of the pressure gauge 11 on one side and the pressure gauge 21 on the other side are the same, it is possible to determine whether all the hydraulic jacks 1 are normal.

  Therefore, the cylinder head bolt 31 can be prevented from being tightened when the hydraulic jack 1 is in an abnormal state, and there is no shortage of the tightening torque of the cylinder head bolt 31. Accidents based on it will not occur.

  In the bolt tightening method of the internal combustion engine of the above embodiment, the number of bolts pulled up by applying the same hydraulic pressure was 4, but in this invention, the number of bolts pulled up by applying the same hydraulic pressure is 2, It may be 3 or 5 or more.

  In the above embodiment, the method of the present invention is used to tighten the plurality of cylinder head bolts 31. However, the method of the present invention may be, for example, a plurality of main bearing bolts, a plurality of crankpin bolts, or a plurality of It may be used to tighten side bolts.

DESCRIPTION OF SYMBOLS 1 Hydraulic jack 5 Hydraulic pump 6, 8, 9 Hydraulic hose 7 Hydraulic jack of one end 11,21 Pressure gauge 31 Cylinder head bolt

Claims (1)

Installing a hydraulic jack having two connection ports for supplying and discharging oil to each bolt of the internal combustion engine having a plurality of bolts;
Connecting a plurality of the hydraulic jacks in series with a hydraulic hose while connecting a hydraulic jack at one end of the plurality of hydraulic jacks connected in series with a hydraulic pump with a hydraulic hose;
Applying hydraulic pressure of the hydraulic jack at a specified value;
Measuring the oil pressure on the hydraulic pump side of the hydraulic jack on the one end and the oil pressure on the opposite side of the hydraulic jack on the one end of the hydraulic jack on the other end of the plurality of hydraulic jacks; And a step of fastening the plurality of bolts and nuts after confirming that the hydraulic pressures at both ends are the same.

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