JP7063786B2 - Spring device - Google Patents

Description

The technique disclosed herein relates to a spring device.

In general, parts fastened to an internal combustion engine may heat up due to the operation of the internal combustion engine. Therefore, a mechanism for suppressing the influence of heat elongation is required so that fasteners such as bolts are not deformed or damaged.

As an example of such a mechanism, Patent Document 1 describes that a spring device having a plurality of disc springs is inserted through a bolt for fastening a component to an internal combustion engine.

Specifically, the manifold mounting structure of the internal combustion engine disclosed in Patent Document 1 includes a tubular case arranged between the bolt head and the manifold, and a tubular case housed in the case and in the axial direction of the bolt. It is configured as a spring device equipped with a plurality of disc springs (disc spring washers) arranged side by side.

Further, Patent Document 2 discloses a tightening device provided with a washer (spring receiver) urged by a disc spring as a spring device created from a viewpoint different from that of Patent Document 1. The washer according to the same document has a portion immersed in the tubular spring box and a portion protruding from the open end of the spring box. The part protruding from the spring box has a slightly smaller diameter than this spring box, and the tightening force of the bolt (tightening bolt) can be known by measuring the amount of protrusion (distance a between the spring receiver and the spring box). Can be done.

Further, Patent Document 3 includes a washer (movable side washer) arranged between the bolt head and the disc spring and urged to the bolt head by a plurality of disc springs, as in the case of Patent Document 2. A spring device (tightening force management device) is disclosed.

Jitsukaisho 59-144160 Jikkai Sho 53-039211 Jitsukaisho 61-145110

The inventors of the present application have considered using a spring device as described in Patent Document 1 to fasten a fuel injection valve to an internal combustion engine. Such a spring device may be used in combination with the washer according to the above-mentioned Patent Documents 2 and 3 for various reasons.

In this case, the settling of the disc spring due to deterioration over time is reflected in the amount of protrusion (immersion amount) of the washer urged by the disc spring. That is, by periodically measuring the amount of protrusion (immersion) of the washer, it is possible to determine the settling of the disc spring.

In order to accurately determine the settling of the disc spring, it is necessary to accurately measure the amount of protrusion of the washer. Such measurement is usually performed using a general measuring instrument such as a caliper, but when a washer as disclosed in Patent Documents 2 and 3 is targeted for measurement, a seat surface for hitting the measuring instrument. Was difficult to secure, and there was room for improvement in its measurement accuracy.

The technique disclosed here has been made in view of this point, and the purpose thereof is to accurately determine the settling of the disc spring.

The present disclosure relates to a spring device through which a bolt for fastening a fuel injection valve is inserted into an internal combustion engine. This spring device includes a case arranged between the fuel injection valve and the bolt head and having an open end, and a plurality of disc springs housed in the case and arranged side by side in the axial direction of the bolt. The washer is disposed between the bolt head and the plurality of disc springs and is urged toward the bolt head by the plurality of disc springs, and the washer is immersed in the case. It has a portion to be formed and a portion to protrude from the open end of the case.

A flange portion having a diameter larger than that of a portion immersed in the case is provided at a portion of the washer that protrudes from the open end of the case, and the flange portion is provided with the plurality of disc springs. When it exerts a regular urging force, it protrudes from the open end of the case at a predetermined interval or more.

According to the above configuration, by providing the flange portion on the washer, a seat surface for hitting a measuring instrument such as a caliper is secured. This makes it possible to accurately measure the distance between the flange and the open end of the case and accurately determine the settling of the disc spring.

That is, the washer protrudes from the case as a result of being urged by a plurality of disc springs. When a plurality of disc springs exert a normal urging force, the flange portion provided on the washer is spaced apart from the open end of the case by a predetermined value or more. In other words, if each disc spring is settled, the regular urging force will not be exerted and the washer will immerse in the case. As a result, the distance between the flange and the open end becomes narrower than specified. Therefore, by measuring the distance between the flange portion provided on the washer and the open end of the case, it is possible to accurately determine the settling of the disc spring.

Further, in the conventional structure, if the disc springs are settled, the top surface of the washer may settle with respect to the open end of the case. In this case, water or dust accumulated on the top surface of the washer may enter the case and adversely affect the service life of the spring device.

On the other hand, when a flange portion is provided on the washer as described above, the sedimentation of the washer is restricted by contacting the flange portion with the opening end of the case. This suppresses the intrusion of water and dust, which is advantageous in ensuring the useful life of the spring device.

Further, on the outer surface of the flange portion, a guideline for the distance between the flange portion and the open end of the case may be displayed.

According to the above configuration, by providing the flange portion on the washer, a space for displaying a guideline of the measured value by the measuring instrument is secured. This is advantageous in accurately determining the settling of the disc spring.

Further, the flange portion may have a measured portion formed by cutting out the outer edge of the flange portion.

According to the above configuration, by cutting out the outer edge of the collar portion, it becomes possible to insert a measuring instrument such as a caliper into the cutout portion. This is advantageous in stabilizing the measurement by the measuring instrument and, by extension, in accurately determining the settling of the disc spring.

Further, according to the above configuration, by providing the measured portion on the outer edge of the flange portion, it is possible to measure the same portion each time instead of measuring a different portion each time. This is advantageous in stabilizing the measurement by the measuring instrument and, by extension, in accurately determining the settling of the disc spring.

Further, the washer may be provided with a regulating mechanism that guides the movement of the collar portion in the axial direction of the bolt and regulates the rotation of the collar portion in the circumferential direction of the bolt.

According to the above configuration, it is possible to regulate the rotation of the collar portion with respect to the case. As a result, the positional relationship between the measured portion and the open end of the case can be kept substantially constant. This is advantageous in stabilizing the measurement by the measuring instrument and, by extension, in accurately determining the settling of the disc spring.

As described above, according to the above-mentioned spring device, it is possible to accurately determine the settling of the disc spring.

FIG. 1 is a perspective view illustrating the configuration of a fuel injection valve. FIG. 2 is a partial perspective view illustrating the configuration of the spring device. FIG. 3A is a vertical sectional view illustrating the configuration of a spring device in a free state. FIG. 3B is a vertical sectional view illustrating the configuration of the spring device in the tightened state. FIG. 4 is a perspective view illustrating the configuration of the flange portion of the spring device. FIG. 5 is a plan view illustrating the configuration of the flange portion of the spring device. FIG. 6A is a diagram corresponding to FIG. 3A illustrating a conventional spring device. FIG. 6B is a diagram corresponding to FIG. 3B illustrating a conventional spring device. FIG. 7 is a flowchart illustrating the procedure for assembling the spring device. FIG. 8 is a flowchart illustrating the management procedure of the spring device.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following description is an example. FIG. 1 is a perspective view illustrating the configuration of the fuel injection valve 2, and FIG. 2 is a partial perspective view illustrating the configuration of the spring device 4.

(1) Fuel injection valve The fuel injection valve 2 shown in FIG. 1 is fastened to a marine diesel engine 1 as an internal combustion engine. The marine diesel engine 1 is configured as a two-stroke one-cycle engine that employs a uniflow scavenging system, and is mounted on a large ship such as a tanker, a container ship, or a car carrier.

The combustion chamber of the marine diesel engine 1 is partitioned by a cylinder liner (not shown), a piston (not shown), and a cylinder cover 11. The fuel injection valve 2 is inserted into the cylinder cover 11 from above and then fastened to the upper surface of the cylinder cover 11 (see FIG. 2).

Specifically, the fuel injection valve 2 has a nozzle portion 21 inserted inside the combustion chamber and a fastening portion 22 fastened to the upper surface of the cylinder cover 11. The injection port portion 21 corresponds to the tip end portion of the fuel injection valve 2, and is arranged so as to face the combustion chamber when it is attached to the marine diesel engine 1. On the other hand, the fastening portion 22 corresponds to the base end portion of the fuel injection valve 2, and is arranged along the upper surface of the cylinder cover 11 when attached to the marine diesel engine 1.

Specifically, the fastening portion 22 is composed of a flange-shaped flange portion, and a pair of left and right insertion openings 22a through which bolts 3 can be inserted are provided at both ends of the flange portion. After inserting the bolt shaft portion 32 into each insertion port 22a, the tip of the bolt shaft portion 32 is screwed into the cylinder cover 11 and the nut 5 is tightened, whereby the fastening portion 22 is fastened to the cylinder cover 11. In the state of being fastened in this way, the fastening portion 22 is tightened by the head portion 31 of the bolt 3 and the nut 5.

The bolt shaft portion 32 refers to a portion extending axially from the head portion 31 of the bolt 3, as shown in FIG. 3A described later. Further, in the following description, the head 31 of the bolt 3 is also simply referred to as a “bolt head 31”.

As shown in FIG. 2, when the fuel injection valve 2 is fastened by the bolt 3, the bolt head 31 is located above the bolt shaft portion 32 and the nut 5. As shown in the figure, the bolt head 31, the nut 5, the spring device 4, the fastening portion 22, and the cylinder cover 11 described later are arranged in this order from above.

As described above, the injection port portion 21 of the fuel injection valve 2 is arranged in the combustion chamber. Therefore, when diesel fuel is burned in the combustion chamber, the fuel injection valve 2 may be thermally expanded due to the combustion. In this case, the above-mentioned fastening portion 22 thermally expands toward the bolt head 31, so that the surface pressure between the nut 5 and the fastening portion 22 and the tightening force of the bolt 3 become excessive, and the bolt 3 and the nut become excessive. 5 may be deformed or damaged, or the gasket attached to the tip of the fuel injection valve 2 may be damaged, and the combustion gas may leak to the outside of the combustion chamber.

Therefore, the marine diesel engine 1 according to the present embodiment has a configuration in which a spring device 4 as shown in FIG. 2 is inserted into a bolt 3 for fastening a fuel injection valve 2 to a cylinder cover 11.

The spring device 4 is arranged between the nut 5 and the fastening portion 22, and incorporates a plurality of disc springs 42. A tightening force can be generated by the elastic force of these disc springs 42. When the fuel injection valve 2 is thermally expanded, each disc spring 42 is elastically compressed to relieve the surface pressure around the bolt head 31 and the nut 5. As a result, the tightening force can be kept substantially constant.

Hereinafter, the spring device 4 will be described in detail.

(2) Spring device FIG. 3A is a vertical cross-sectional view illustrating the configuration of the spring device 4 in the free state, and FIG. 3B is a vertical cross-sectional view illustrating the configuration of the spring device 4 in the tightened state. Further, FIG. 4 is a perspective view illustrating the configuration of the flange portion 44 of the spring device 4, and FIG. 5 is a plan view illustrating the configuration of the flange portion 44 of the spring device 4.

In the following description, the direction along the bolt shaft portion 32 is referred to as "axial direction of bolt 3" or simply "axial direction", and the direction along the circumference of the central axis C of the bolt shaft portion 32 is referred to as "axial direction". It is referred to as "circumferential direction of bolt 3" or simply "circumferential direction".

As shown in FIG. 2, the spring device 4 has the bolt 3 inserted between the bolt head 31 and the fastening portion 22 (specifically, below the nut 5 and above the fastening portion 22). It is intervening.

More specifically, as shown in FIGS. 3A and 3B, the spring device 4 according to the present embodiment is arranged between the bolt head 31 and the fuel injection valve 2 (specifically, the fastening portion 22), and is open at both ends. Between the cylinder 41 having the ends 41a and 41b, the plurality of disc springs 42 housed in the cylinder 41 and arranged side by side in the axial direction of the bolt 3, and the bolt head 31 and the plurality of disc springs 42. It includes a washer 43 that is arranged and urged toward the bolt head 31 by a plurality of disc springs 42.

More specifically, the tubular body 41 extends in the vertical direction and is formed in a long tubular shape through which the bolt shaft portion 32 can be inserted. Specifically, the upper end of the tubular body 41 forms an open end 41a that abuts on the lower surface of the nut 5 via the washer 43. On the other hand, the lower end of the tubular body 41 forms an open end 41b in contact with the upper surface of the fastening portion 22. The tubular body 41 is an example of a “case”.

As shown in FIGS. 3A and 3B, a common bolt shaft portion 32 is inserted through the open ends 41a and 41b of the tubular body 41. Further, the disc spring 42 is introduced into the cylinder 41 through the opening end 41a on the upper end side of the cylinder 41. On the other hand, the opening end 41b on the lower end side of the tubular body 41 supports the disc spring 42 from below so that the disc spring 42 does not fall off.

Further, the plurality of disc springs 42 are housed in the tubular body 41 in a state of being stacked in the vertical direction. A common bolt shaft portion 32 is inserted through each disc spring 42.

The plurality of disc springs 42 exert an urging force in the direction in which the bolt shaft portion 32 extends, specifically, in the direction in which the bolt head portion 31 (and the nut 5) and the fastening portion 22 are separated from each other. The magnitude of this urging force is defined by the spring constant of the entire plurality of disc springs 42. In the present embodiment, the spring constant of the entire plurality of disc springs 42 is smaller than both the spring constant of the bolt 3, particularly the bolt head 31, and the spring constant of the fuel injection valve 2, particularly the fastening portion 22. Is set to.

Further, the washer 43 is formed in a short cylinder shape that extends in the vertical direction and allows the bolt shaft portion 32 to be inserted. Specifically, the washer 43 is provided with an insertion hole 43c that penetrates the washer 43 in the vertical direction. The inner diameter of the insertion hole 43c is slightly larger than that of the bolt shaft portion 32.

The lower end portion 43b of the washer 43 is immersed in the tubular body 41 and is in contact with the plurality of disc springs 42 from above. On the other hand, the upper end portion 43a of the washer 43 protrudes from the open end 41a on the upper end side of the tubular body 41 (hereinafter, also simply referred to as “open end 41a of the tubular body 41”), and abuts on the nut 5 from below. ing. The washer 43 is slidable in the axial direction along the inner wall of the tubular body 41 and the outer peripheral surface of the bolt shaft portion 32.

The lower end portion 43b of the washer 43 is an example of "a portion immersed in the cylinder", and the upper end portion 43a of the washer 43 is an example of "a portion protruding from the open end of the cylinder".

As shown in FIGS. 3A and 3B, the same bolt shaft portion 32 that is inserted into the tubular body 41 is inserted into the insertion hole 43c of the washer 43. The urging force generated by the plurality of disc springs 42 acts on the washer 43. By this urging force, the washer 43 is urged in a direction protruding from the open end 41a of the tubular body 41 and is pressed against the lower surface of the nut 5.

The upper end portion 43a of the washer 43 is provided with a flange portion 44 having a diameter larger than that of the lower end portion 43b of the washer 43. The flange portion 44 has substantially the same diameter as the outer peripheral surface of the tubular body 41, and a plurality of disc springs 42 urge the washer 43 so as to be separated from the open end 41a of the tubular body 41. It stands out.

When it is assumed that a plurality of disc springs 42 exert a regular urging force, for example, immediately after assembling the spring device 4, the flange portion 44 is provided with a predetermined interval h or more with respect to the opening end 41a of the tubular body 41. It is designed to protrude in the open. This interval h is narrower in the tightened state (state in which the nut 5 is tightened) shown in FIG. 3B than in the free state (state in which the nut 5 is loosened) shown in FIG. 3A.

Further, when the disc springs 42 are settled, the regular urging force is not exerted, and the washer 43 is immersed in the cylinder 41. In this case, the distance h between the flange portion 44 and the opening end 41a of the tubular body 41 is narrower than a predetermined value. This interval h increases or decreases depending on the dimension H from the open end 41a of the tubular body 41 to the upper surface of the flange portion 44, for example. Therefore, by measuring the dimension H, it is possible to determine the settling of the disc spring 42. The dimension H gradually becomes smaller as it is used for a long period of time. As the dimension H becomes smaller, it can be considered that the urging force by the disc spring 42 becomes smaller.

Further, as shown in FIGS. 3A and 3B, a set screw 45 is attached to the washer 43. The screw tip of the set screw 45 is screwed into the outer peripheral portion of the washer 43 on the lower end portion 43b side. Therefore, the set screw 45 slides in the axial direction integrally with the washer 43.

On the other hand, the head 45a of the set screw 45 is arranged inside the through groove 41c provided in the tubular body 41, and is exposed to the outside through the through groove 41c. The through groove 41c is formed in an oval shape extending in the axial direction, and penetrates the tubular body 41 in the thickness direction.

When assembling the spring device 4, the screw tip of the set screw 45 is inserted into the through groove 41c, and then the screw tip is screwed into the washer 43 inserted in the cylinder 41. As a result, the set screw 45 functions as a stopper for the washer 43.

Further, when the through groove 41c as described above is used, the head portion 45a of the set screw 45 can be slid along the direction in which the through groove 41c extends. As a result, the movement of the washer 43 and the flange portion 44 in the axial direction can be guided, and the rotation of the washer 43 and the flange portion 44 in the circumferential direction can be restricted. The set screw 45 and the through groove 41c constitute the regulation mechanism according to the present embodiment.

Further, as shown in FIGS. 4 and 5, the flange portion 44 has a measured portion 44a formed by cutting out the outer edge of the flange portion 44. Specifically, the measured portion 44a cuts out the outer edge of the flange portion 44 toward the radial center portion of the flange portion 44 (corresponding to the center portion of the insertion hole 43c).

Further, as shown in FIG. 5, by providing the flange portion 44 on the washer 43, a space for engraving various information is secured. For example, on the outer surface of the flange portion 44 according to the present embodiment, the initial value of the dimension H and the usage limit are displayed as a guideline for the distance h between the flange portion 44 and the opening end 41a of the tubular body 41.

Specifically, the measured value "XXX" of the dimension H at the time of assembly and in the free state is engraved on the upper surface of the flange portion 44 as the initial value of the dimension H. The upper surface of the flange portion 44 is also engraved with the lower limit value "LIMIT YY" of the dimension H in the free state as the usage limit of the dimension H. When the dimension H is not more than the lower limit value, it can be determined that the plurality of disc springs 42 do not exhibit the regular urging force and the disc springs 42 are settled. The initial value and the lower limit value of the dimension H are values reflecting the individual difference of the disc spring 42 for each spring device 4, and are usually different values for each spring device 4.

(3) Management of Spring Device FIG. 6A is a diagram corresponding to FIG. 3A illustrating the conventional spring device 104, and FIG. 6B is a diagram corresponding to FIG. 3B illustrating the conventional spring device 104. Similar to the spring device 4 according to the present embodiment, the conventional spring device 104 includes a tubular body 141, a plurality of disc springs 142, and a washer 143 so that the bolt 3 can be inserted from above. It is configured.

However, the conventional spring device 104 is different from the spring device 4 according to the present embodiment in that the washer 143 is not provided with a flange portion. Therefore, in the conventional spring device 104, as shown in FIG. 6B, the entire washer 143 can be immersed in the tubular body 141.

Even in the conventional spring device 104, when the disc spring 142 is settled, the washer 143 is still immersed in the cylinder 141. Therefore, similarly to the spring device 4 according to the present embodiment, the settling of the disc spring 142 can be determined by measuring the distance between the top surface 143a of the washer 143 and the opening end 141a of the tubular body 141.

However, there are individual differences in the performance of the disc spring 142 for each spring device 104. Since this individual difference is reflected in the amount of protrusion of the washer 143, a determination method in consideration of such individual difference is required.

Therefore, in the conventional spring device 104, in the tightening state immediately after assembly (particularly, the tightening state realized by a constant tightening torque), the top surface 143a of the washer 143 and the open end 141a of the cylinder 141 are surfaced. The thickness of the washer 143 was adjusted so as to be one. When such a management method is adopted, when the disc spring 142 is settled, the washer 143 is immersed in the cylinder 141. Immediately after assembly, what was considered to be flush with each other will be absorbed according to the settling. Therefore, by measuring the displacement of the washer 143 with respect to the cylinder 141, the dish is taken into consideration the individual difference of the disc spring 142. It becomes possible to determine the settling of the spring 142.

As a result of studying the management method of the spring device, the inventors of the present application newly found the following problems. That is, in order to accurately determine the settling of the disc spring, it is required to accurately measure the displacement amount of the washer with respect to the cylinder. Such measurement is usually performed using a general measuring instrument such as a caliper, but when a washer 143 as shown in FIGS. 6A and 6B is used as a measurement target, a seat surface for hitting the measuring instrument is secured. It was difficult, and there was room for improvement in its measurement accuracy.

Further, in the first place, it is troublesome and inconvenient to adjust the top surface 143a of the washer 143 and the open end 141a of the tubular body 141 flush with each other as in the conventional spring device 104.

On the other hand, in the spring device 4 according to the present embodiment, the flange portion 44 is provided on the washer 43 as shown in FIGS. 3A and 3B. By providing the flange portion 44, a seating surface for hitting a measuring instrument such as a caliper is secured. As a result, the dimension H from the upper surface of the flange portion 44 to the open end 41a of the tubular body 41 can be accurately measured, and the settling of the disc spring 42 can be accurately determined.

Further, in the conventional spring device 104, when the disc spring 142 is settled, the top surface 143a of the washer 143 has to settle with respect to the opening end 141a of the tubular body 141. In this case, water and dust accumulated on the top surface 143a of the washer 143 may enter the cylinder 141 and adversely affect the useful life of the spring device 104.

On the other hand, when the washer 43 is provided with the flange 44 as in the present embodiment, the washer 43 is restricted from settling by contacting the flange 44 with the opening end 41a of the tubular body 41. This suppresses the intrusion of water and dust, which is advantageous in ensuring the useful life of the spring device 4.

Further, as shown in FIG. 5, by providing the flange portion 44 on the washer 43, a space for displaying a guideline of the measured value by a measuring instrument such as a caliper is secured. As a result, unlike the conventional spring device 4, the top surface of the washer 43 and the opening end 41a of the tubular body 41 are not adjusted flush with each other, and a guideline for independently setting for each spring device 4 is worked. It can be visually recognized by a person. Since the step of adjusting the top surface of the washer 43 and the open end 41a of the tubular body 41 to be flush with each other can be omitted, the assembly of the spring device 4 becomes easy. In addition, it is advantageous in accurately determining the settling of the disc spring 42.

Further, as shown in FIGS. 4 and 5, by providing the measured portion 44a in which the outer edge of the flange portion 44 is cut out, it becomes possible to insert a measuring instrument such as a caliper into the measured portion 44a. .. This is advantageous in stabilizing the measurement by the measuring instrument and, by extension, in accurately determining the settling of the disc spring 42.

Further, by providing the measured portion 44a on the outer edge of the flange portion 44, it is possible to measure the same portion each time instead of measuring a different portion each time. This is advantageous in stabilizing the measurement by the measuring instrument and, by extension, in accurately determining the settling of the disc spring 42.

Further, as shown in FIGS. 3A and 3B, by providing the spring device 4 with a regulating mechanism (set screw 45 and through groove 41c), it is possible to regulate the rotation of the flange portion 44 with respect to the tubular body 41. .. As a result, the positional relationship between the measured portion 44a and the open end 41a of the tubular body 41 can be kept substantially constant. This is advantageous in stabilizing the measurement by the measuring instrument and, by extension, in accurately determining the settling of the disc spring 42.

-Assembly and management procedure of spring device-
FIG. 7 is a flowchart illustrating an assembly procedure of the spring device 4, and FIG. 8 is a flowchart illustrating a management procedure of the spring device 4.

When assembling the spring device 4, the steps illustrated in FIG. 7 are carried out.

Specifically, first, as shown in step S11 of FIG. 7, a plurality of disc springs 42 and a washer 43 are incorporated into the tubular body 41. Subsequently, as shown in step S12, the dimension H in the free state is measured, and the measured value and the value obtained by subtracting a predetermined value from the measured value are calculated. The measured value here corresponds to the initial value of the dimension H. On the other hand, the value obtained by subtracting a predetermined value from the measured value corresponds to the above-mentioned usage limit.

Then, as shown in step S13, the initial value of the dimension H and the usage limit are marked on the upper surface of the flange portion 44, respectively. After that, as shown in step S14, the set screw 45 is screwed into the washer 43 to complete the assembly of the spring device 4. Although not shown, when the spring device 4 is used, the bolt 3 may be inserted through the insertion hole 43c provided in the washer 43 and the nut 5 may be tightened.

On the other hand, when managing the spring device 4, the process illustrated in FIG. 8 is carried out.

Specifically, first, as shown in step S21 of FIG. 8, the spring device 4 is put into a free state by loosening the bolt 3 inserted through the spring device 4. Subsequently, as shown in step S22, the dimension H from the open end 41a of the tubular body 41 to the upper surface of the flange portion 44 is measured. This measurement is carried out by inserting a measuring instrument into the measured portion 44a provided in the flange portion 44.

Then, as shown in step S23, the measured value obtained in step S22 is compared with the usage limit stamped on the upper surface of the flange portion 44. Here, when the measured value exceeds the usage limit (step S23: YES), it is considered that the settling of the disc spring 42 is sufficiently small, and it is determined that the spring device 4 has not reached the end of its life (step S24). On the other hand, when the measured value is equal to or less than the usage limit (step S23: NO), it is considered that the disc spring 42 has a large settling, and it is determined that the spring device 4 has reached the end of its life (step S25).

<< Other Embodiments >>
In the above-described embodiment, a configuration using a long cylindrical cylinder 41 has been exemplified, but the configuration is not limited to this configuration. A member having another shape may be used as a case.

1 Marine diesel engine (internal combustion engine)
2 Fuel injection valve 3 Bolt 31 Bolt head 4 Spring device 41 Cylinder (case)
41a End of cylinder 41c Through groove (regulatory mechanism)
42 Belleville spring 43 Washer 43a Upper end of washer (part protruding from the open end of the cylinder)
43b Lower end of washer (part of immersion in the cylinder)
44 Collar 44a Measured part 45 Set screw (regulatory mechanism)
h interval

Claims (4)

A spring device through which a bolt for fastening a fuel injection valve is inserted into an internal combustion engine.
A case located between the fuel injection valve and the bolt head and having an open end,
A plurality of disc springs housed in the case and arranged side by side in the axial direction of the bolt,
A washer is provided between the bolt head and the plurality of disc springs and is urged toward the bolt head by the plurality of disc springs.
The washer has a portion that is immersed in the case and a portion that protrudes from the open end of the case.
Of the washers, a portion protruding from the open end of the case is provided with a collar portion having a diameter larger than that of a portion immersed in the case, and the flange portion is normally formed by the plurality of disc springs. A spring device characterized in that when the urging force of the case is exerted, the spring device projects at a predetermined interval or more with respect to the open end of the case. In the spring device according to claim 1,
A spring device characterized in that a guideline for the distance between the flange portion and the open end of the case is displayed on the outer surface of the flange portion. In the spring device according to claim 1 or 2.
The flange portion is a spring device characterized by having a measured portion formed by cutting out an outer edge of the flange portion. In the spring device according to claim 3,
A spring device characterized in that the washer is provided with a regulating mechanism that guides the movement of the flange portion in the axial direction of the bolt and regulates the rotation of the collar portion in the circumferential direction of the bolt.

Images