JPS6213802B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicular transformer that is designed to reduce the weight of a bellows top plate and a conservator bottom plate, particularly in a conservator equipped with metal bellows.

Figure 1 shows an example of a vehicle transformer.

The transformer main body has a structure in which a coil 2 and an iron core 3 are housed in a tank 1. As the insulating oil 4 filled in the tank 1, silicone oil has been adopted in recent years. A conservator 5 is disposed above the outside of the main tank 1, and a metal bellows 6 made of a thin steel plate is housed inside the conservator 5. That is, the conservator 5 has a bottom plate 8,
It is formed from a side plate 14, a ceiling plate 13, and a metal bellows 6. The metal bellows 6 has a cylindrical shape, for example, and has a disk-shaped top plate 7 at its upper edge.
The bottom part is welded to the bottom plate 8 of the conservator 5. Insulating oil 4a is sealed outside the metal bellows 6, and is connected to the main body tank 1 via a connecting pipe 9. On the other hand, the inner side 10 of the metal bellows communicates with the outside air via a vent pipe 11 and an oil pot 12.

In this conventional type, when the temperature rises during operation of the transformer, the insulating oil 4 inside the main body tank 1 expands in volume. The expanded insulating oil flows into the conservator 5 through the connecting pipe 9 that communicates the main body tank 1 and the conservator 5, and the metal bellows 6 responds by the amount of expansion, and the bellows top plate 7 is pushed down. . At this time, the air inside the bellows 10 is
1 and the oil pot 12 to the outside. On the other hand, if the oil temperature decreases, the opposite effect will occur. Therefore, as the metal bellows 6,
The amount of expansion and contraction that can absorb the expansion and contraction of the insulating oil 4 (second
(indicated by L in the figure) is required. That is, as shown in Fig. 2, when lubricating the transformer in advance, insulating oil is filled in the conservator 5 until the bellows top plate 7 is on side A, and when the transformer reaches its maximum temperature. The setting is such that when the temperature reaches the lowest temperature, the top plate 7 lowers to the B side, and when the lowest temperature is reached, the top plate 7 rises to the C side. Here, during normal operation, the transformer main body and the conservator 5 are in a pressureless state inside and no internal pressure acts on them. However, since the main body of the transformer accommodates the core 3 and coil 2 in the main body tank 1, it must have mechanical strength to withstand them, and must also have strength to withstand vibrations while the vehicle is running. Moreover, when injecting the insulating oil 4 into the main body tank 1, the inside of the main body tank 1 is brought into a vacuum state, so negative pressure is applied. Therefore, the main tank 1 is designed to withstand an internal pressure of ±1 kg/cm ² in terms of strength by providing reinforcements 1a and 1b on its outer surface.

On the other hand, there are three types of pressures that act within the conservator 5, which is connected to the main body tank 1 through the connecting pipe 9.

(1) Negative pressure during evacuation (2) Sudden positive pressure (3) Slow positive pressure The conservator 5 must have a structure that can cooperate with the transformer body in terms of strength against these pressures. The internal pressure effects within the conservator when these pressures are applied will be explained below.

(1) When vacuuming When the inside of the transformer body is evacuated, the inside of conservator 5 also becomes negative pressure at the same time. At this time, the top plate 7 of the metal bellows 6 rises as shown in FIG.
It overlaps with the ceiling plate 13 of the conservator 5. That is,
Figure 3 shows a graph showing the relationship between the negative pressure inside the conservator 5 (Kg/cm ² ) and the amount of displacement (mm) of the bellows top plate 7. As is clear from this graph, the inside of the conservator 5 is The moment the negative pressure is applied, the bellows top plate 7 deforms, but it instantly overlaps with the conservator ceiling plate 13, and as a result of the combined rigidity of both, the deformation does not progress, but on the contrary, it slightly decreases. This is because the bellows top plate 7 and the conservator ceiling plate 13 are in close contact with each other, and no internal pressure acts on the gap between them. On the other hand, only the part of the bottom plate 8 of the conservator 5 that is sandwiched between the outer periphery of the metal bellows 6 and the conservator side plate 14 receives internal pressure, but this part has a small area and is close to the conservator side plate 14, so it is strong. I don't have any worries.

(2) In the case of sudden pressure action If a sudden pressure rise occurs in the main tank 1 due to an electrical short circuit inside the transformer, etc., the pressure inside the conservator 5 will be calculated based on this pressure value, the rate of pressure rise, and the pressure. Internal pressure determined by the transmission path resistance acts.

In the case of vehicular transformers, the duration of arc energy due to short-circuit accidents, etc. can be suppressed to an extremely short time (t1sec in the graph of Figure 4) by protective measures such as relays. Furthermore, as shown in FIG. 1, since the main tank 1 and the conservator 5 are connected by a connecting pipe 9 having a relatively small diameter, a considerable pressure loss occurs due to the resistance of the pipe.
Figure 4 shows the duration of the pressure inside the main tank 1 (sec) and the pressure generated inside the conservator 5 (Kg/cm ² ).
An example of actually measuring the relationship between As is clear from this figure, the pressure inside the main tank 1 is 1Kg/ ^cm2 .
When acting for a time of t1 sec (arc energy connection time), the pressure P1 inside the conservator 5 becomes a pressure increase value of P1≪1Kg/cm ² in this example.
If this action time becomes longer and becomes t2sec > t1sec, the pressure inside the conservator becomes P2, which becomes higher than the pressure P1 at t1sec and becomes P2 > P1, but even in this state, P2 is the pressure inside the main tank 1 of 1 kg/
It can only be a value much smaller than cm ² . As can be seen from these measured values, even if a sudden pressure rise occurs inside the transformer due to an internal electrical short circuit, the pressure inside the conservator 5 will be reduced due to the operation of the protective relays and the pressure loss at the connecting pipe 9. The pressure becomes lower than the pressure inside the main tank 1. Therefore, against this sudden pressure action, the conservator 5
Furthermore, it is possible to make the rigidity of the metal bellows 6 lower than that of the main tank 1 without any problem.

(3) In the case of gradual pressure rise When a gas component of the insulating oil 4 is generated inside the transformer due to corona discharge, for example, the volume of the insulating oil gradually expands and the insulating oil 4 flows into the conservator 5. Therefore, the metal bellows 6 responds. and,
As shown in Fig. 2, when the metal bellows 6 contracts and its top plate 7 completely contacts the conservator bottom plate 8, and insulating oil flows in beyond the allowable expansion/contraction amount, the pressure inside the conservator 5 gradually increases. I will do it. Therefore, when the pressure inside the conservator 5 rises slowly as in this example, the structure of the conservator 5 must have a rigidity that is coordinated with the main tank.

As mentioned above, when designing a conservator, the case where it is necessary to cooperate with the main tank for strength is when a slow pressure rise occurs inside the transformer, and the other two cases require coordination with the main tank. Rigidity can be lowered. For this reason, conventional conservators usually adopt the structure shown in FIG. 2.

In other words, the bottom plate 8 and ceiling plate 1 of the conservator are parts that are required to withstand a positive pressure of 1 kg/ ^cm2.
3, a side plate 14, a metal bellows 6, and a bellows top plate 7. Among these, the metal bellows 6 has a welded structure made of a thin plate of stainless steel or the like, and is designed to sufficiently withstand positive pressure. The conservator ceiling board 13 is composed of a thin plate to reduce weight.
A reinforcing material 13a is provided on the outer surface to withstand positive pressure.
13b are attached in a cross shape. On the other hand, the conservator bottom plate 8 is made to correspond to the size of the bellows top plate 7 and the contact length of the bellows 6 so that when the bellows top plate 7 is lowered, it contacts the bottom plate 8 and suppresses deformation of the bellows top plate 7. A constricted portion 8a is provided, which also serves to reinforce the bottom plate 8.

However, the configuration of the conventional conservator described above has the disadvantage of increasing weight as described below.

Vehicle transformers are required to be more lightweight than ever, and at the same time, transformer parts are required to be maintenance-free. Therefore, even if two conservators were used in the past, in order to avoid complicating the configuration and diversifying the maintenance required by two conservators, in recent years, in order to satisfy the required response amount, conventional metal bellows diameters have been used. There is a trend toward reducing the number of conservators to one by using larger diameter bellows. When a large-diameter metal bellows is used in this way, the conservator that houses it also becomes large. As a result, the pressure-receiving areas of the bellows top plate and the conservator bottom plate also increase, so these need to be constructed to withstand internal pressure. in this case,
In the conventional conservator shown in Figure 2, the thickness of these parts must be increased to withstand a positive pressure of 1 kg/cm ² , but this increases the weight of the conservator. It was hot. Also, instead of increasing the thickness, it is possible to provide separately prepared reinforcing materials on the outer surface of the bottom plate 8, like the reinforcing materials 13a and 13b provided on the conservator ceiling board 13.
This method was not a preferable method because it inevitably resulted in an increase in weight due to the reinforcing material.

The present invention was proposed to solve the above-mentioned drawbacks of conventional conservators, and an object of the present invention is to provide a vehicular transformer that is lightweight by eliminating the need for increased plate thickness or special reinforcing materials. shall be.

An embodiment of the vehicular transformer of the present invention will be described with reference to FIG. 5, in which the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals.

In the figure, 1 is the main tank of the transformer, and 5 is the conservator. The main tank 1 and the conservator 5 are connected by a connecting pipe as in the conventional type.
In addition, the conservator 5 includes a side plate 14, a ceiling plate 13,
Consisting of the reinforcing materials 13a, 13b and the bottom plate 8,
A metal bellows 6 with a top plate 7 on its upper edge is provided inside. The conservator bottom plate 8 is also provided with a constricted portion 8a, with which the top plate 7 comes into close contact when the metal bellows 6 contracts.

On the other hand, on the top surface of the main tank 1, the main tank 1
reinforcing members 20, 21, 22 are provided. These reinforcing materials 20, 21, and 22 are provided to increase the rigidity of the main tank 1 to withstand an internal pressure of ±1 kg/ ^cm2 , but in the embodiment of the present invention, these reinforcing materials 20, 21, and 22 are It is arranged at a position close to the outer surface of the beta bottom plate 8. For example, the upper surface of the center reinforcing member 20 corresponds to the constricted portion 8a of the conservator bottom plate 8, and the upper surfaces of the left and right reinforcing members 21, 22 correspond to the outer portions of the constricted portion 8a of the conservator bottom plate 8. established in These reinforcing materials 20, 21, 22 and the conservator bottom plate 8 (including the constricted portion 8a) may be placed close to each other so as to be in constant contact, but preferably, a slight gap is maintained. The size of this gap is set to be less than or equal to the amount of deformation (set amount of deformation) of the conservator bottom plate 8 that occurs when normal internal pressure is applied.

As described above, there are three types of internal pressure that act within the conservator 5. Among these, the case where the conservator 5 is required to withstand an internal pressure of +1 Kg/cm ² in cooperation with the main tank 1 is a case where the internal pressure of the conservator 5 gradually increases. In the above embodiment, when the insulating oil in the main body tank 1 expands and gradually flows into the conservator 5, the bellows top plate 7 is pushed down. Further, as the expansion continues, the metal bellows 6 comes into close contact with each other, and the bellows top plate 7 and the constricted portion 8a of the conservator bottom plate 8 overlap. This aperture part 8
A supports the bellows top plate 7 as reinforcement, but if the pressure continues to rise further, both of these will deform downward, and when the set amount of deformation is reached, the main tank 1
The reinforcing members 20, 21, 22 help prevent further deformation. These reinforcing materials 20, 21, and 22 have the necessary rigidity for the main tank 1 to withstand an internal pressure of ±Kg/cm ² and can sufficiently withstand the pressure increase inside the conservator 5. Therefore, deformation of the conservator bottom plate 8 by more than the set amount is reliably prevented.

As explained above, the main body tank of a transformer is provided with many reinforcing materials in order to withstand internal pressure and vibrations received when the vehicle is running.In the present invention, a part of this reinforcing material is Since it is made to correspond to the position of the bottom plate, especially the throttle part for reinforcement, the reinforcement of the main tank also serves as the reinforcement of the conservator bottom plate, and it can be used with the bellows top plate without preparing a separate reinforcing material. The amount of deformation of the conservator bottom plate can be suppressed within an appropriate range.

In particular, by having the configuration as in the present invention,
Although the bellows top plate and the conservator bottom plate have an increased pressure receiving area as the capacity of the conservator increases, there is no need to increase the thickness of the bellows top plate and the conservator bottom plate by appropriately selecting the amount of deformation. Therefore, the conservator can be made as thin as necessary, the weight of the bellows top plate and the conservator bottom plate can be reduced, and the weight of a large-capacity conservator can also be reduced.

Although the above description has been made regarding the case of one conservator, even when two conservators are used, the same can be applied to each individual conservator, contributing to the weight reduction of each conservator.

[Brief explanation of the drawing]

Figure 1 is a vertical view schematically showing a vehicle transformer with a conservator installed, Figure 2 is a vertical view showing the configuration of a conventional conservator, and Figure 3 is the pressure inside the conservator and the conservator ceiling plate. 4 is a diagram showing the relationship between the duration of the pressure inside the main body tank and the stress generated in the conservator when the pressure suddenly increases. FIG. FIG. 3 is a cross-sectional view showing one embodiment. 1...Main tank, 2...Coil, 3...Iron core, 4...
Insulating oil, 4a... Insulating oil in the conservator, 5... Conservator, 6... Metal bellows, 7... Bellows top plate, 8... Conservator bottom plate, 8a... Constricted part for reinforcing the conservator bottom plate, 9... Connection pipe, 10 ...Inside bellows, 11...Vent pipe, 12...Oil pot, 13...Conservator ceiling board, 13a, 13b...Reinforcing material for ceiling board, 14...Conservator side board, 20, 21, 2
2...Reinforcement material for the main tank and conservator bottom plate.

Claims (1)

[Claims] 1 A conservator consisting of a ceiling plate, a side plate and a bottom plate is provided, and a metal bellows with a top plate on the upper edge is built into the upper part of the main tank containing the iron core, coil and insulating oil. In the vehicular transformer in which the outside of the metal bellows communicates with the inside of the main body tank, the conservator bottom plate is formed with a reinforcing constriction portion that overlaps with the bellows top plate when the metal bellows is contracted and brought into close contact with the main body. A transformer for a vehicle, characterized in that a reinforcing material for the main tank is arranged on the upper surface of the tank so as to be located close to the lower surface of the conservator bottom plate.