JPH0457366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to an oil filter, in particular a cartridge type oil filter having a relief valve arrangement mounted with a spring producing a shape memory effect (SME).

2. Description of the Related Art A conventional cartridge type oil filter will be explained with reference to the drawings. As shown in FIG. 6, this oil filter has a casing 1, and inside the casing 1 there is a A spring 7 is arranged between the end plate 21 and the casing top wall. A cylindrical filter element 2 and a reinforcing tube 20 are arranged coaxially with the cylindrical filter element 2 between the upper end plate 21 and the lower end plate 11 . The reinforcing cylinder 20 is provided with a large number of holes. An outer chamber 12 is formed between the filter element 2 and the casing 1, and an inner chamber 13 is formed inside the reinforcing tube 20.

The lower end plate 11 is supported by a bottom plate 3 fixed to the inner lower part of the casing 1. An oil port 8 is formed in the bottom plate 3, a diaphragm 5 is placed on the bottom plate 3 to close the oil port 8, and a spring 6 is provided between the diaphragm 5 and the lower end plate 11. The diaphragm 5 and the spring 6 form a check valve. The center of the bottom plate 3 is provided with an internal thread, which is threadedly connected to the oil outlet 9 of the mounting bracket 10. At this time, the oil port 8 and the oil inlet 18 of the bracket 10 are fluid-tightly communicated with the outside by the seal ring 4 disposed between the bottom plate 3 and the bracket 10.

Further, the relief valve device 1 is mounted on the upper end plate 21.
4 is provided. The relief valve device 14 includes a cylindrical valve case 15 fixed to an upper end plate 21 by caulking, a spring 17 disposed inside the valve case and supported by a spring seat 16 provided therein, and an upper end plate 21. The seal plate 24 is pressed by a spring 17 against a bent portion 23 formed around the center hole 22 of the plate 21.

When the oil filter is activated, the pressure generated by the oil pump (not shown) is applied to the oil inlet 18.
When this pressure exceeds a predetermined level, the diaphragm 5 is opened against the spring 6, and oil flows into the outer chamber 12 from the oil port 8.
In the steady operating state, the oil in the outer chamber 12 passes through the filter element 2 and the holes in the reinforcing tube 20,
The oil flows into the inner chamber 13, and at this time, foreign substances in the oil are passed through. The oil in the inner chamber 13 is sent to the engine (not shown) through the oil outlet 9, and then sent back to the oil inlet 18 by the oil pump. When the temperature is low and the oil viscosity is high, it becomes difficult for the oil to pass through the filter element, and the outer wall 1
2 is high pressure. In order to release this high pressure, the seal plate 24 moves downward against the force of the spring 17 to form a bypass passage and drain the oil in the outer chamber 12 to the center hole 22 and the hole formed in the valve case 15. 15a into the inner wall 13.

Problems to be Solved by the Invention By the way, in conventional oil filters, when the engine is started at a low temperature, the viscosity of the engine oil is high and the pressure loss due to viscosity is large, so the seal plate of the relief valve device is difficult to open due to a delay in operation. High pressure was generated inside the oil filter.
This high pressure damaged the filter element and casing. Therefore, in the past, a method was adopted in which a separate thermovalve device was attached to the oil filter, and the oil pressure was automatically released when the engine oil temperature fell below a certain level. However, with this method, the relief valve device and thermovalve device had to be installed separately, and problems such as an increase in the size of the oil filter, an increase in the number of parts, and a complicated manufacturing process could not be solved. . Furthermore, a method of using a bimetal to serve as both a relief valve and a thermovalve is disclosed, for example, in Japanese Utility Model Publication No. 56-27939, but bimetal is used because the amount of displacement of the seal plate in response to temperature changes is small. At low temperatures, the only function that can be achieved is to reduce the spring elasticity of the seal plate, and the bypass passage is not completely formed, so that almost no high viscosity oil flows.

On the other hand, shape memory effect (SME) materials whose shape changes due to martensitic transformation are well known.
Currently, several types of temperature sensing actuation devices using this material have been proposed. For example, Japanese Unexamined Patent Publication No. 19793/1983 shows a breaker that changes shape and switches when energized SME material. Furthermore, a temperature sensing control device has been proposed in which a cooling water control valve for an automobile engine is actuated by an SME spring.

However, no device has been proposed to date that reduces the size of the oil filter relief valve device that functions as a pressure release valve, reduces the number of parts, and reliably opens the valve at low temperatures.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an oil filter that does not have the above-mentioned drawbacks by installing an SME spring in a relief valve device.

Embodiments Examples of the present invention will be described below with reference to the drawings.

Each of the embodiments shown in FIGS.
It is shown as a modification of the known oil filter shown in the figures, and identical parts are designated with the same reference numerals.

FIG. 1 shows an SME spring 30a that creates a shape memory effect (SME) between the seal plate 24 that closes the center hole 22 of the upper end plate 21 and the valve case 15.
Here is an example where is fixed. As a fixed part, the valve case 15 is fixed to the upper end plate 21. Instead of the valve case 15, one end of the SME spring 30a may be directly fixed to the casing.

The SEM spring 30a has a reversible shape memory effect. That is, the martensitic transformation point is set within the temperature range of 10° to 50°C, and the SME spring 30a becomes a martensitic structure at temperatures below this transformation point, and forms a matrix at higher temperatures, and each phase It will have a different shape. Therefore SME
Below the transformation point, the spring 30a is in the expanded and contracted state shown in FIG. 2, opening the seal plate 24 and forming a bypass passage with a large passage area. Therefore, at low temperatures, oil can reliably pass through the bypass passage and no high pressure is generated within the casing. In the steady working state, the oil temperature is higher than the above transformation point, so the SME spring 30a forms a matrix,
Return to the contracted state shown in FIG. In this valve closed state, the seal plate 24 receives oil pressure from both the inner chamber 13 and the outer chamber 12, and when the oil pressure in the outer chamber 12 is higher than the inner chamber 13 by a certain level, the SME
The spring 30a is stretched in the valve opening direction and releases high pressure to the inner chamber 13. When the pressure in the outer chamber 13 drops below the above level, the seal plate 24
The elasticity of the SME spring 30a returns the valve to the closed state shown in FIG. Like this SME spring 30
a has a two-way shape memory effect in which the shape changes depending on the temperature above and below the transformation point.

In the embodiment shown in FIGS. 3 and 4,
A combination of the SME spring and a normal spring without shape memory effect is used, and the normal spring is disposed between the sealing plate 24 and a fixed part, such as the valve case 15. The conventional spring 31 is mounted in tension to facilitate the deformation of the SME spring 30b into a stretched state at a temperature below its transformation point. In this embodiment, when the temperature is higher than the transformation point, the SME spring 30b returns to its parent state and closes the seal plate 24. At this time, the normal spring 31 pulls the seal plate 24 to the valve closing position. However, at low temperatures,
The SME spring 30b changes to the martensitic phase with a large force, and moves the seal plate 24 to the valve opening position against the elasticity of the spring 31.

FIG. 4 shows an example in which a normal spring 31 is used as a compression spring.

FIG. 5 shows an example in which a normal spring 31 is wound around an SME spring 30c. The sealing plate 24 has a cylindrical portion 24a in which the SME spring 30c is housed, and a flange 24b formed on the top of the cylindrical portion 24a and contacting the upper end plate 21 to close the center hole 22. A normal compression spring 31 is arranged between the flange 24b and the valve case 15.

At low temperatures, the SME spring 30c is in a martensitic phase against the spring 31 and is stretched between the upper end plate 21 and the cylindrical portion 24a with a large force, thereby moving the seal plate 24 downward. As a result, the flange 24b separates from the center hole 22 and becomes open. Conversely, at low temperatures, the SME spring 30c is in a contracted state as a parent phase, and the seal plate 24 is assisted by the elasticity of the spring 31 to return to the valve closing position. In the valve closed position, the seal plate 24
may be pressed against the upper end plate 21 by both the SME spring 30c and the spring 31 or only by the elasticity of the spring 31. In this case, when the flange 24b receives high oil pressure through the center hole 22, the seal plate 24 opens against the elasticity of the spring 31 or, if necessary, the SME spring 30c, and when the oil pressure decreases, this elasticity The valve is automatically returned to the closed position. In some cases, the SME spring 30c may be replaced by the spring 31.
Alternatively, an SME spring may be disposed between the outer flange 24b and the valve case 15, and a normal spring 31 may be disposed within the cylindrical portion 24a. In this case, the SME spring is in a contracted state at low temperatures and is in an expanded state at high temperatures.

The above SME springs 30a and 30b are made of TiNi.
alloy, CuZnX alloy (X is Si, Sn, Al or Ga) or GuAlNi alloy. The alloy composition is selected so that the martensitic transformation temperature is in the temperature range of 10° to 50°C. The above alloy material was formed into a coil shape, vacuum sealed in a quartz tube at 10 ^-5 torr, and heated to 800°C.
Annealed for 2 hours. After the strain is removed by this annealing, it is rapidly cooled in cold water to form a martensitic phase. This coil is, for example, constrained to a stretched length, held in the air at 400° C. for 100 hours, and then water quenched. In this way, the reversible shape memory effect is obtained by deforming the martensitic phase, heating it under restraint, and causing reverse transformation. Alternatively, the reversible shape memory effect can be obtained by generating fine precipitates in the matrix and then deforming it, or by deforming the martensitic phase beyond its limit, but in any case, This invention can be practiced if the shape can be reversibly deformed by 80% or more.

SME springs are coated with an oil-resistant material to prevent chemical changes caused by corrosive components contained in oil. Such an oil-resistant material is coated on the surface of the SME spring by fusing synthetic rubber such as butadiene acrylonitrile rubber or polychloroprene, or by plating with zinc, chromium, or cadmium alloy.

Effects of the Invention As described above, in this invention, since the SME spring is used in the relief valve device of the oil filter, the relief valve device can be downsized and the number of parts thereof can be reduced, and the relief valve can be reliably opened at low temperatures. be able to. Furthermore, in this invention, the SME spring can be used to repeatedly perform three operations: opening the valve at low temperatures, closing the valve at high temperatures, and opening the valve at high temperatures and under high pressure to form a bypass passage.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a relief valve device used in the oil filter of the present invention; Fig. 2 is a cross-sectional view showing the seal plate in the valve open state; Fig. 3 is a second embodiment using a normal spring together. Cross-sectional view of example; 4th
The figure shows a sectional view of the third embodiment; FIG. 5 shows a sectional view of the fourth embodiment; and FIG. 6 shows a sectional view of a conventional oil filter. DESCRIPTION OF SYMBOLS 1... Casing, 2... Filter element, 10... Bracket, 12... Outer chamber, 13
... Inner chamber, 14 ... Relief valve device, 15
...Valve case, 17...Spring, 21...
... Upper end plate, 22 ... Center hole, 24 ... Seal plate, 30a, 30b ... SME spring, 31
...Normal spring.

Claims (1)

[Claims] 1. A filter element disposed within a casing that allows oil to flow into the filter element, and a bypass passage that bypasses the filter element and allows the oil to flow out when the pressure inside the casing becomes high. In an oil filter having a relief valve device, the relief valve device comprises:
It has a sealing plate for opening and closing the bypass passage, and an SME spring disposed between the fixed part in the casing and the sealing plate and made of a shape memory effect material, and the SME spring has an angle of 10° or more. It has a transformation point set within a temperature range of 50℃,
At a temperature below the transformation point, the seal plate takes on a shape that opens the valve, and at a temperature higher than the transformation point, the seal plate takes on a shape that allows the valve to close.Furthermore, when the pressure inside the casing is higher than a certain level when the valve is closed, An oil filter characterized in that the seal plate is opened by oil pressure against spring elasticity. 2. The upper part of the filter element is closed with an upper end plate, and the lower part thereof is closed with a lower end plate supported by a bottom plate having an oil port,
an outer chamber is formed between the casing and the filter element, and an inner chamber is formed within the filter element, the relief valve device being in contact with the center hole formed in the upper end plate and the upper end plate; Usually, a seal plate that closes the center hole and receives oil pressure from the inner chamber and the outer chamber, a valve case that is fixed to the upper end plate and has a through hole, and is arranged between the seal plate and the valve case. Ta
Claim 1 comprising: SME spring;
Oil filter as described in section. 3. The SME spring has a reversible shape memory effect, and has a two-way shape memory effect that takes a different shape depending on the temperature above and below the transformation point.
Oil filter as described in section. 4 Between the seal plate and the fixed part,
2. The oil filter according to claim 1, wherein a conventional spring is arranged to promote the deformation of the SME spring when the SME spring deforms at a temperature below or above the transformation point. 5. The oil filter according to claim 1, wherein the SME spring is coated with an oil-resistant material. 6 The above SME spring is elastically deformed by the oil pressure and the seal plate opens when the oil pressure in one of the outer and inner chambers is higher than the other by a certain level in the valve closed state where the seal plate is in contact with the upper end plate. The oil filter according to claim 2, which moves to a different position.