JP2001300211A - Relief valve for filter apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relief valve, simple in structure, reduced in the number of parts, capable of being manufactured at a low cost, capable of being operated smoothly and certainly and also good in assembling properties. SOLUTION: A valve plug 22 having a C-shaped cross section is fitted to the side wall 25 of a cylindrical valve support 23 having a bottom part 24 and having a plurality of valve holes 26 provided to the side wall 25 thereof so that the inside surface thereof comes into close contact with the outer surface of the side wall 25 of the valve support 23 to close the valve holes. A projected stopper part 27, which sets the position of the valve plug 22 in a height direction and prevents the detachment of the valve plug 22 from the valve support 23, is formed to the side wall 25 of the valve support 23. A projected stopper part 28 preventing the rotation of the valve plug 22 around the valve support 23 is formed to the side wall 25 of the valve support 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relief valve for a filtration device (particularly for an oil filter suitably used for filtering lubricating oil of an internal combustion engine of an automobile).

[0002]

2. Description of the Related Art Conventionally, in an oil filter used for filtering lubricating oil of an internal combustion engine of an automobile, the performance of the oil filter is sometimes improved by using a relief valve. The relief valve is provided on a wall between the inflow-side chamber and the filtration-side chamber separated by the filtration element housed in the casing. A conventional example in which a relief valve is used for an oil filter will be described with reference to FIG. 8. Referring to FIG. 8, the oil flows into an outer chamber (6) of a filtration element (1) housed in a casing (11) having a top plate (12). Oil flows in through the hole (14), passes through the outer chamber (6) and passes through the inner chamber (7), and is filtered.The outlet (1) is formed in the inner chamber (7).
The oil is allowed to flow out from 5). In this type of oil filter, the central part of the side facing the outlet (15) of the inner chamber (almost the center position on the top plate side of the filtration element (1)) Further, a relief valve (31) capable of communicating the outer chamber (6) and the inner chamber (7) is provided.

[0003] The relief valve (31) opens when the pressure difference between the inflow side chamber and the filtration chamber is equal to or higher than a predetermined pressure. Alternatively, when the filter medium is clogged by contaminants and the oil pressure increases, the valve is opened to form a bypass, and the supply and circulation of the oil are performed properly and sufficiently.

The above-mentioned relief valve (31) is connected to an end plate (4) of the filter medium as shown in FIG. 8, and is housed in a cylindrical case (32) having a cutout on the side wall. (3
3), the valve body (34) made of a hard plate material such as a metal plate is pressed to close the valve port (4a), and as the oil pressure increases, the valve element (34) is closed.
It is a structure that opens and closes apart from a).

[0005]

The conventional relief valve (31) has a cylindrical case (32) and a coil spring (3).
3), the valve element (34) is required, the number of parts is large, the cost tends to be high, and the assemblability is not good.

An object of the present invention is to improve the valve structure of a relief valve, to have a simple structure, to reduce the number of parts, to manufacture it at low cost, and to move it smoothly and reliably. Another object of the present invention is to provide a relief valve having good assemblability.

[0007]

Means for Solving the Problems [Invention according to claim 1]
A relief valve for a filtration device, which is provided on a wall between an inflow-side chamber and a filtration-side chamber separated by a filtration element housed in a casing, and is opened when a differential pressure between the inflow-side chamber and the filtration chamber is equal to or higher than a predetermined pressure. A cylindrical valve support having a bottom and a plurality of valve holes formed in a side wall, a valve body having a C-shaped cross section, and an inner surface of the valve body is formed on an outer surface of a side wall of the valve support. A relief valve for a filtration device, which is fitted to a side wall of the valve support so as to close and close the valve hole.

When the pressure difference between the inflow-side chamber and the filtration chamber exceeds a predetermined pressure, the pressure of the fluid (oil) applied to the valve body from the inside of the cylindrical valve support through the valve hole causes the cross section C The valve body having the letter shape is bent and elastically deformed so as to enlarge the letter shape, and a gap is formed between the inner surface of the valve body and the outer face of the side wall of the valve support. As the inflow side chamber (outside chamber 6) and the filtration chamber (inside chamber 7)
Is formed, and a fluid supply and circulation are properly and sufficiently performed. When the pressure difference is eliminated, the valve returns to its original shape and closes. The structure of the relief valve is simple, and the valve opening and closing operations are performed by the elastic deformation of the valve body having a C-shaped cross section, and the adjustment of the valve opening pressure is also easy.
Further, since the pressure can be uniformly applied to the inner surface of the valve body to the outer surface of the side wall of the valve support, stable sealing performance can be exhibited.

A relief valve disclosed in Japanese Utility Model Laid-Open Publication No. 7-14110, which is a well-known technique, comprises a cylindrical member having a plurality of openings formed in a peripheral wall and a cutout portion formed on the outer periphery of the cylindrical member. This is a structure in which a valve-shaped valve body is fixed by rivets. Further, the valve body is expanded with the portion fixed by the rivet as a fixed fulcrum. On the other hand, the present invention has a simpler structure in which the valve body is fitted to the side wall of the valve support without using a rivet, so that the manufacturing is easy and the valve opening operation is performed at a fixed fulcrum. This is different in that it is not expanded but performed by elastic deformation of the entire valve element, and has an advantage that the load on the valve element is small.

The invention according to claim 2 is provided on a wall between the inflow-side chamber and the filtration-side chamber separated by a filtration element housed in the casing, and a differential pressure between the inflow-side chamber and the filtration chamber is predetermined. A relief valve for a filtration device that opens at a pressure equal to or higher than a pressure, wherein a valve body having a C-shaped cross section is provided on a cylindrical valve support body provided with a plurality of valve holes in a side wall, and the outer surface of the valve body is the valve. To close the valve hole in close contact with the inner surface of the side wall of the support,
A relief valve for a filtration device, which is fitted to a side wall of the valve support.

With the above structure, when the differential pressure between the inflow side chamber and the filtration chamber becomes equal to or higher than a predetermined pressure, the pressure of the fluid (oil) applied to the valve body from the outside of the cylindrical valve support through the valve hole causes the cross section C The valve body having a character shape is bent and elastically deformed so as to reduce the character shape, a gap is generated between the outer surface of the valve body and the inner surface of the side wall of the valve support, the valve is opened, and the valve is opened through the space and the valve hole. As the inflow side chamber (outside chamber 6) and the filtration chamber (inside chamber 7)
Is formed, and a fluid supply and circulation are properly and sufficiently performed. When the pressure difference is eliminated, the valve returns to its original shape and closes. The structure of the relief valve is simple, and the valve opening and closing operations are performed by the elastic deformation of the valve body having a C-shaped cross section, and the adjustment of the valve opening pressure is also easy.
In addition, since the pressure can be uniformly applied to the inner surface of the side wall of the valve support on the outer surface of the valve body, stable sealing performance can be exhibited.

[Invention according to claim 3] A protruding stopper for positioning the valve body in the height direction and preventing the valve body from coming off from the valve support body near the end of the side wall of the valve support body. It is a relief valve for filtration devices of Claim 1 or 2 in which a part is located.

[Invention according to claim 4] The relief valve for a filtration device according to any one of claims 1 to 3, wherein a projecting stopper portion for preventing the valve body from rotating relative to the valve support is formed.

[Invention according to claim 5] A rib-shaped reinforcing portion is formed on an outer surface or an inner surface of the valve body.
A relief valve for a filtration device according to any one of claims 1 to 4.

[0015]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a relief valve 21 according to an embodiment of the present invention before assembly, and FIG.
1, FIG. 3 is a perspective view before assembling a relief valve 21 according to another embodiment, and FIG. 4 is a longitudinal sectional view of a filtration element using the relief valve 21 shown in FIG. is there.

FIG. 1 is an exploded perspective view of the relief valve 21 as viewed from the bottom 24 side of the valve support 23. The relief valve 21 shown in FIG. 1 includes a valve body 22 and a valve support 23. The valve body 22 has a predetermined height h and has a cross section (plane) C
It is formed in a cylindrical shape so as to form a character. A gap formed between both ends of the C-shape is indicated by l. The valve body 22 is made of an elastically deformable material, and for example, plastic or metal can be used. As a plastic, it is preferable to use FRP.
The rigidity of the valve body 22 can be easily increased by forming a rib-like reinforcing portion 22c extending in the circumferential direction on the outer surface of the valve body 22.

The valve support 23 is cylindrical and has a bottom 24
(Represented as an upper surface in FIG. 1). Side wall 25
Are provided with a plurality of valve holes (through holes) 26. Valve 2
2 is fitted to the side wall 25 of the valve support 23 such that the inner side surface 22a is in close contact with the outer surface of the side wall 25 of the valve support 23 to close the valve hole 26. The inner surface 22a of the valve body 22 is formed to have the same outer diameter as the outer diameter of the outer surface of the side wall 25 of the valve support 23 or smaller (larger curvature). Inner surface 22a of valve body 22
Is formed smaller than the outer diameter of the outer surface of the side wall 25 of the valve support 23, so that a spring force for closing the valve hole 26 (initial load for closing the valve) is applied.

On the side wall of the valve support 23, a projecting stopper portion 27 for positioning the valve 22 in the height direction and preventing the valve 22 from coming off the valve support 23 is formed. In the illustrated example, a protruding stopper 27 is formed in a flange shape on the edge of the side wall of the valve support body 23 on the bottom 24 side. The protruding stopper 27 allows the valve body 22
Is positioned in the height direction, the valve body 22 is held at a predetermined position, and the valve body 22 is prevented from coming off the valve support body 23.

On the side wall 25 of the valve support 23, a protruding stopper 28 for preventing the valve body 22 from rotating around the valve support 23 is formed. In the illustrated example, the valve support 2
A rib-shaped projecting stopper 28 is formed on the outer surface of the side wall 25 along the height direction, and the projecting stopper 28 is located between the gaps 1 of the valve body 22, 22
Is prevented from rotating around the valve support 23.

The bottom 24 of the side wall 25 of the valve support 23
On the opposite side, a flange portion 29 is continuously provided, and this flange portion 29 can be used as a mounting portion for attaching the filtration element to an end plate or the like.

FIG. 2 is a longitudinal sectional view of an oil filter in which the above-described relief valve 21 is mounted on the filtration element 1 and housed in a casing.

The filter element 1 having a hollow cylindrical shape as a whole has a filter medium 2 formed by, for example, folding a filter paper and winding the filter medium 2 in an annular shape. The filter medium 2 is reinforced by the arranged porous cylinder 5 and is housed in a cylindrical casing 11 having a top plate 12. An outer chamber 6 and an inner chamber 7 are formed in the casing 11 with the filter element 1 as a boundary. Reference numeral 8 denotes a leaf spring that presses and supports the filtration element.

An inflow hole 14 communicating with the outer chamber 6 is formed on the outer peripheral side of a socket plate 13 attached to the side of the casing 11 opposite to the top plate portion 12, and an inner chamber is formed in the center of the socket plate 13. An outflow hole 15 is formed which communicates with the nozzle 7. At this outflow hole 15, a screw or the like is used to attach to an unillustrated bracket or the like. The oil flowing from the inflow hole 14 passes through the filter medium 2 from the outer chamber 6, is filtered into the inner chamber 7, and is discharged from the outflow hole 15 to the outside of the filter body. Reference numeral 16 denotes an anti-drain valve, and 17 denotes a gasket.

The relief valve 21 is attached to the flange 29 of the valve support 23 at the center opening of the end plate 3 which closes one end of the filter medium of the filter element 1. In addition, by using a flammable material as the end plate 3 (and 4) and attaching the relief valve 21 to the end plate 3 in a manner separable therefrom, disposal after use becomes easy. The flange portion 29 of the valve support body 23 may also serve as the end plate 3 that closes one end of the filter medium of the hollow cylindrical filter element 1. That is, the end plate 3
The valve support 23 and the valve support 23 may be formed by one member. Thus, the end plate and the valve support can be made of the same part, and the number of parts can be reduced.

The relief valve 2 configured as described above
In a normal state, the valve body 22 has an inner surface 22a.
Are in close contact with the outer surface of the side wall 25 of the valve support 23 to close the valve hole 26, and the outer chamber 6 and the inner chamber 7 are isolated.
When the oil pressure increases as the engine speed increases, or when the filter medium becomes clogged with contaminants and the oil pressure increases, a large pressure difference between the outer chamber 6 and the inner chamber 7 occurs. Thus, the pressure of the fluid (oil) applied to the valve body 22 from the inside of the valve support body 23 through the valve hole 26 causes the valve body 22 having a C-shaped cross section to bend and elastically deform so as to enlarge the character shape, A gap is formed between the inner surface of the valve body 22 and the outer surface of the side wall of the valve support 23, the valve is opened, and the inflow-side chamber (outer chamber 6) and the filtration chamber (inner chamber 7) are opened using the gap and the valve hole 26 as passages. ) Is formed, and the supply and circulation of the fluid are performed properly and sufficiently. When the pressure difference is eliminated, the valve body 22 returns to its original shape and closes.

FIG. 3 shows a relief valve 2 according to the second aspect.
1 is shown. The relief valve 21 shown in FIG. 3 includes a valve body 22 and a valve support 23. The valve body 22 has a predetermined height h, and is formed in a cylindrical shape so as to have a C-shaped cross section (plane). A gap formed between both ends of the C-shape is indicated by l. The rigidity of the valve body 22 can be easily increased by forming a rib-like reinforcing portion 22c extending in the circumferential direction on the inner surface of the valve body 22.

The valve support 23 has a cylindrical shape, and has a bottom 24 on one side in the height direction.
a is formed. The side wall 25 has a plurality of valve holes (through holes).
26 are provided. The valve body 22 has an outer surface 22b.
Is fitted to the side wall 25 of the valve support 23 so as to closely contact the inner surface of the side wall 25 of the valve support 23 and close the valve hole 26. The outer surface 22b of the valve body 22 is formed to be equal to or larger (smaller in curvature) than the inner diameter of the inner surface of the side wall 25 of the valve support 23. By forming the outer surface 22b of the valve body 22 to be larger than the radius of the inner surface of the side wall 25 of the valve support 23, the valve hole 2 is formed.
6, a spring force (initial load of closing the valve) is applied.

On the side wall of the valve support 23, a projecting stopper 27 for positioning the valve 22 in the height direction and preventing the valve 22 from coming off the valve support 23 is formed. In the illustrated example, the projecting stopper 2 is formed in a flange shape on the inner edge of the side wall of the valve support 23 opposite to the bottom 24.
7 are formed (see FIG. 4). The position of the valve body 22 in the height direction is determined by the protruding stopper 27, the valve body 22 is held at a predetermined position, and the valve body 22 is prevented from coming off the valve support 23.

A projection stopper 28 is formed on the side wall 25 of the valve support 23 to prevent the valve body 22 from rotating relative to the valve support 23. In the illustrated example (see FIG. 3B), a rib-shaped projecting stopper 28 is formed on the inner surface of the side wall 25 of the valve support 23 along the height direction thereof. It is located between the gaps 1 of the valve body 22 to prevent the valve body 22 from rotating around the valve support 23.

The bottom portion 24 of the side wall 25 of the valve support 23
On the opposite side, a flange portion 29 is continuously provided, and this flange portion 29 can be used as a mounting portion for attaching the filtration element to an end plate or the like.

FIG. 4 shows the filtration element 1 equipped with the above-mentioned relief valve 21. The filter element 1 having a hollow cylindrical shape as a whole is disposed on the inner periphery of the filter medium 2, in which both ends of a filter medium 2, for example, formed by folding a filter paper and winding in an annular shape are closed by upper and lower end plates 3 and 4. The filter medium 2 is reinforced by the porous cylinder 5. The filtration element 1 is appropriately accommodated in a cylindrical casing having a top plate, and an outer chamber and an inner chamber are formed with the filtration element 1 as a boundary.

The relief valve 21 is mounted on the flange 29 of the valve support 23 at the center opening of the end plate 4 which closes one end of the filter medium of the filter element 1. The flange portion 29 of the valve support 23 closes one end of the filter medium of the hollow cylindrical filter element 1.
May also be used. That is, the end plate 4 and the valve support 23 may be configured by one member. Thus, the end plate and the valve support can be made of the same part, and the number of parts can be reduced.

The relief valve 2 configured as described above
In a normal state, the valve body 22 has an outer surface 22b.
Closes the valve hole 26 in close contact with the inner surface of the side wall 25 of the valve support 23, but when the oil pressure increases with an increase in the engine speed or when the filter medium is clogged by contaminants, the oil pressure increases. When the pressure increases, a large pressure difference occurs between the outside and the inside of the filtration element 1, whereby
The pressure of the fluid (oil) applied to the valve body 22 from the outside of the valve support 23 through the valve hole 26 causes the valve body 22 having a C-shaped cross section to bend and elastically deform so as to make the shape smaller, and A gap is formed between the outer side surface and the inner surface of the side wall of the valve support 23, the valve is opened, and a bypass passage is formed in which the outside and the inside of the filtration element 1 communicate with each other using the gap and the valve hole 26 as a passage. Supply and circulation of water properly and sufficiently. When the pressure difference is eliminated, the valve body 22 returns to its original shape and closes. A fluid discharge hole 24a is formed in the bottom 24 of the valve support 23, and the discharge hole 24a is used as a fluid discharge hole.

FIG. 5 shows the relief valve 21 shown in FIG.
FIG. 4 is a longitudinal sectional view of an oil filter in which a relief valve 21 having substantially the same configuration as that of FIG.

The relief valve 21 is provided so as to protrude from the center opening position of the lower end plate 4 for closing the lower end of the filter medium 2. The upper end plate 3 for closing the upper end of the filter medium 2 is entirely closed. The basic configuration of the casing 11, the socket plate 13, and the like is the same as that shown in FIG.
An outer chamber 6 and an inner chamber 7 are formed in the casing 11 with the filter element 1 as a boundary. Reference numeral 8 denotes a leaf spring that presses and supports the filtration element.

The relief valve 21 is mounted on the flange 29 of the valve support 23 at the center opening of the end plate 4. 3 and 4, the side wall of the valve support 23 does not have a flange-shaped projecting stopper 27 on the inner edge opposite to the bottom 24. Valve support 23
A peripheral edge 4 a of the center opening of the end plate 4 located near the side wall end of the end plate 4 functions as a protrusion stopper instead of the protrusion stopper 27. A fluid discharge hole 24 a is formed in the bottom 24 of the valve support 23, and is fitted to the central cylindrical portion of the socket plate 13 at the discharge hole 24 a.

An anti-drain valve 31 is provided outside the valve support 23. The anti-drain valve 31 includes a bottom portion 32, a side wall 33, and a bottom portion 24, which contact the bottom portion 24, the side wall 25, and the flange portion 29 of the valve support 23 of the relief valve 21, respectively.
It has a flange portion 34. A valve opening / closing portion 35 extends obliquely from the vicinity of the flange portion 34 to the outer peripheral side of the socket plate 13 so as to close the inflow hole 14 and lands. Side wall 33
Is formed with a through hole communicating with the valve hole 26 of the valve support 23.

The relief valve 2 configured as described above
In a normal state, the valve body 22 has an outer surface 22b.
Closes the valve hole 26 in close contact with the inner surface of the side wall 25 of the valve support 23, but when the oil pressure increases with an increase in the engine speed or when the filter medium is clogged by contaminants, the oil pressure increases. When the pressure increases, a large pressure difference occurs between the outside and the inside of the filtration element 1, whereby
The pressure of the fluid (oil) applied to the valve body 22 from the outside of the valve support 23 through the valve hole 26 causes the valve body 22 having a C-shaped cross section to bend and elastically deform so as to make the shape smaller, and A gap is formed between the outer side surface and the inner surface of the side wall of the valve support 23, the valve is opened, and a bypass passage is formed in which the outer side 6 and the inner side 7 of the filtration element 1 communicate with each other using the gap and the valve hole 26 as a passage. Supply and circulate the fluid properly and sufficiently. When the pressure difference is eliminated, the valve body 22 returns to its original shape and closes.

FIG. 6 is a longitudinal sectional view of an oil filter showing another example in which the relief valve 21 is mounted on the filtration element 1 and housed in a casing.

The relief valve 21 is provided so as to protrude from the center opening position of the upper end plate 3 that closes the upper end of the filter medium 2. The basic configuration of the casing 11, the socket plate 13, and the like is the same as that shown in FIG. Casing 1
Inside 1, an outer chamber 6 and an inner chamber 7 are formed with the filter element 1 as a boundary. Reference numeral 9 denotes a coil spring that presses and supports the filtration element.

The relief valve 21 is attached to the flange 29 of the valve support 23 at the center opening of the end plate 4. 3 and 4, the side wall of the valve support 23 does not have a flange-shaped projecting stopper 27 on the inner edge opposite to the bottom 24. Valve support 23
A peripheral edge 4 a of the center opening of the end plate 4 located near the side wall end of the end plate 4 functions as a protrusion stopper instead of the protrusion stopper 27. The bottom 24 of the valve support 23 is closed.

The relief valve 2 configured as described above
In a normal state, the valve body 22 has an outer surface 22b.
Closes the valve hole 26 in close contact with the inner surface of the side wall 25 of the valve support 23, but when the oil pressure increases with an increase in the engine speed or when the filter medium is clogged by contaminants, the oil pressure increases. When the pressure increases, a large pressure difference occurs between the outside and the inside of the filtration element 1, whereby
The pressure of the fluid (oil) applied to the valve body 22 from the outside of the valve support 23 through the valve hole 26 causes the valve body 22 having a C-shaped cross section to bend and elastically deform so as to make the shape smaller, and A gap is formed between the outer side surface and the inner surface of the side wall of the valve support 23, the valve is opened, and a bypass passage is formed in which the outer side 6 and the inner side 7 of the filtration element 1 communicate with each other using the gap and the valve hole 26 as a passage. Supply and circulate the fluid properly and sufficiently. When the pressure difference is eliminated, the valve body 22 returns to its original shape and closes.

FIG. 7 shows another example of a protruding stopper for preventing the valve body 22 from rotating with respect to the valve support 23. As shown in FIG.
(A) is an example of a relief valve 21 of the type shown in FIGS. 1 and 2 (the invention according to claim 1), and (b) is a type shown in FIGS. Such invention)
An example of the relief valve 21 is shown. 5A, the valve support member 23 of the valve body 22 is formed on the inner surface of the valve body 22 by a projecting stopper portion 28a formed so as to protrude into a valve hole 26 provided in a side wall 25 of the valve support body 23. It is trying to prevent turning around. In (b),
A protruding stopper portion 28b formed on the outer surface of the valve body 22 so as to protrude into a valve hole 26 provided in a side wall 25 of the valve support body 23 prevents the valve body 22 from rotating around the valve support body 23. I have to.

The embodiment of the present invention has been described above.
The present invention is not limited to those described above, and can be implemented with appropriate modifications and additions within the scope of the present invention.

[0045]

The relief valve according to the present invention has a simple structure, can reduce the number of parts, can be manufactured at low cost, and can be smoothly and reliably moved.
Good assemblability. It is stable, can secure a sufficient flow rate, and can be reduced in weight.

[Brief description of the drawings]

FIG. 1 is a perspective view before assembling a relief valve 21 according to an embodiment.

FIG. 2 is a longitudinal sectional view of an oil filter using the relief valve 21 shown in FIG.

FIG. 3A shows a relief valve 21 according to another embodiment.
(B) is a cross-sectional view of the relief valve 21 before assembling.

FIG. 4 is a longitudinal sectional view of a filtration element using the relief valve 21 shown in FIG.

FIG. 5 is a longitudinal sectional view showing another example of the oil filter using the relief valve 21.

FIG. 6 is a longitudinal sectional view showing another example of the oil filter using the relief valve 21.

FIG. 7 is a cross-sectional view of the relief valve 21 showing an example of protruding stopper portions 28a and 28b for preventing the valve body 22 from rotating around the valve support 23.

FIG. 8 is a longitudinal sectional view showing a conventional oil filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration element 6 Outer chamber 7 Inner chamber 11 Casing 12 Top plate part 21 Relief valve 22 Valve body 22c Reinforcement part 23 Valve support 24 Bottom part 25 Side wall 26 Valve hole 27 Projection stopper part 28 Projection stopper part 28a Projection stopper part 28b Projection stopper Department

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 35/02 E

Claims (5)

[Claims] 1. A filter provided on a wall between an inflow-side chamber and a filtration-side chamber separated by a filtration element housed in a casing, and opens when a pressure difference between the inflow-side chamber and the filtration chamber is equal to or higher than a predetermined pressure. A relief valve for a filtration device, comprising: a cylindrical valve support having a bottom portion and a plurality of valve holes formed in a side wall; a valve body having a C-shaped cross section; and an inner surface of the valve body supporting the valve. A relief valve for a filtration device, which is fitted to a side wall of the valve support so as to be in close contact with an outer surface of a side wall of the body and close the valve hole. 2. A filter provided on a wall between an inflow-side chamber and a filtration-side chamber separated by a filtration element housed in a casing, and opens when a differential pressure between the inflow-side chamber and the filtration chamber is equal to or higher than a predetermined pressure. A relief valve for a filtration device, comprising: a cylindrical valve support having a plurality of valve holes formed in a side wall; a valve body having a C-shaped cross section; and an outer surface of the valve body formed on an inner surface of a side wall of the valve support. A relief valve for a filtration device, wherein the relief valve is fitted to a side wall of the valve support so as to close and close the valve hole. 3. A protruding stopper for positioning the valve body in a height direction and preventing the valve body from coming off from the valve support body, near the side wall end of the valve support body. 3. The relief valve for a filtration device according to 1 or 2. 4. The relief valve for a filtration device according to claim 1, wherein a protruding stopper portion for preventing the valve body from rotating relative to the valve support is formed. 5. The relief valve for a filtration device according to claim 1, wherein a rib-shaped reinforcing portion is formed on an outer surface or an inner surface of the valve body.