JP6931680B2 - Oil strainer - Google Patents

Description

The present invention relates to an oil strainer. More specifically, it relates to an oil strainer that filters oil in a storage chamber and supplies it to a rotating machine of a vehicle.

The transmission mounted on the vehicle includes a power transmission mechanism such as a transmission mechanism and a differential mechanism, and a casing accommodating these power transmission mechanisms. The bottom of the casing is an oil storage chamber in which oil used as hydraulic oil or lubricating oil in the mechanical parts constituting the power transmission mechanism is stored. In the casing, an oil pump that sucks up the oil accumulated in the oil storage chamber, a hydraulic control unit equipped with a valve mechanism for controlling the oil pressure to be supplied to mechanical parts, and an oil pump that sucks up the oil from the oil storage chamber. An oil strainer or the like for removing foreign substances contained in the oil is provided.

In Patent Document 1, an oil element, which is a filter medium, is sandwiched between a flange of a resin upper case member having a communication port to an oil pump and a flange of a resin lower case member having an oil suction port. , A technique for manufacturing an oil strainer by joining these flanges by vibration welding has been shown. The oil in the casing during operation contains fine bubbles due to being agitated by mechanical parts. For this reason, in an oil strainer manufactured by vibration welding, air bubbles in the oil may accumulate on the flange and be sucked into the oil pump. When the oil pump sucks in a large mass of air, sufficient oil pressure may not be generated or noise may be generated. Therefore, in the oil strainer of Patent Document 1, a notch is formed in the flange to allow air bubbles to escape upward, thereby preventing air bubbles from accumulating on the flange.

Patent No. 3420541

By the way, during operation, the bubbles contained in the oil are maintained finely, so that there is no functional problem even if the oil containing the bubbles is sucked up by the oil pump. However, when the engine is temporarily stopped, fine air bubbles contained in the oil may combine in the oil strainer to form a large mass of air. As described above, the communication port to the oil pump is often formed on the upper side of the oil strainer body where air tends to collect. Therefore, for example, when the oil pump sucks in a large mass of air when the engine is restarted. There is.

An object of the present invention is to provide an oil strainer capable of preventing the air from being sucked by an oil pump even when a large mass of air is generated inside.

(1) The oil strainer according to the present invention (for example, the oil strainer 5 described later) filters the oil supplied from the storage chamber (for example, the oil storage chamber 23 described later) to the machine parts of the vehicle. A box-shaped main body provided in the storage chamber (for example, the main body 50 described later), a filter medium provided inside the main body (for example, a filter medium 54 described later), and the main body using the filter medium as a part of a partition wall. An inflow member that connects the dust side chamber (for example, the dust side chamber 71 described later) and the clean side chamber (for example, the clean side chamber 72 described later), which are partitioned inside the storage chamber, and the dust side chamber. (For example, an inflow pipe 61 described later) and an outflow member (for example, an outflow pipe 62 described later) connecting the clean side chamber and the oil pump are provided, and the main body is provided in the storage chamber. The dust side chamber is arranged on the upper side in the vertical direction with respect to the clean side chamber. In the present invention, the "dust side chamber" means an oil chamber of oil containing foreign matter before passing through the filter medium, and the "clean side chamber" means the foreign matter after passing through the filter medium. Means the oil chamber of the removed oil.

(2) In this case, the inflow member penetrates the bottom of the main body (for example, the lower case 51 described later) and the partition wall (for example, the separate plate 53 described later), and one end thereof (for example, the suction port 61a described later). ) Is a pipe member facing the storage chamber and the other end (for example, the outlet 61b described later) faces the dust side chamber, and the outflow member is the upper part of the main body (for example, the upper case 52 described later) and the said. It is preferable that the pipe member penetrates the partition wall, one end thereof (for example, the inflow port 62a described later) faces the clean side chamber, and the other end (for example, the connection port 62b described later) is connected to the oil pump.

(3) In this case, it is preferable that a concave recess (for example, a recess 513 described later) is formed in the bottom portion downward in the vertical direction, and the end portion of the outflow member faces the recess.

(4) In this case, the oil strainer is an air discharge member (for example, an air discharge member (for example, an air discharge flow path 524 described later) forming an air discharge flow path (for example, an air discharge flow path 524 described later) that communicates the upper part of the dust side chamber with the outside of the main body. , The air discharge pipe 523) described later, and an air discharge valve (for example, the air discharge valve 56 described later) that opens and closes the air discharge flow path are preferably provided.

(5) In this case, the air discharge valve includes a valve body provided in the air discharge flow path (for example, a valve body 561 described later) and an oil passage provided with the oil pump (for example, an oil passage described later). A valve body (for example, a valve body 562 described later) that urges the valve body in the valve closing direction using the line pressure that is the hydraulic pressure in 35) as a pilot pressure, and an urging member that urges the valve body in the valve opening direction. (For example, a spring 563 described later), the elastic force of the urging member is larger than the load due to the line pressure when the oil pump is stopped, and the minimum of the line pressure while the oil pump is operating. It is preferable that the load is set to be smaller than the load due to pressure.

(1) The oil strainer according to the present invention has a box-shaped main body, a filter medium provided inside the main body, and a dust side chamber and a clean side in which the filter medium is partitioned inside the main body as a part of a partition wall. It includes an inflow member that connects the chamber, the oil storage chamber and the dust side chamber, and an outflow member that connects the clean side chamber and the oil pump. Further, when this main body is provided in the storage chamber, the dust side chamber is arranged on the upper side in the vertical direction from the clean side chamber. In the above oil strainer, the oil guided from the storage chamber to the dust side chamber by the inflow member passes through the filter medium, flows into the clean side chamber vertically downward from the dust side chamber, and then flows from the clean side chamber. Guided by the oil pump. As described above, in the oil strainer according to the present invention, by arranging the clean side chamber on the lower side in the vertical direction from the dust side chamber, air bubbles contained in the oil are accumulated in the dust side chamber and stored in the clean side chamber. It can be prevented from flowing in. As a result, even when air bubbles contained in the oil are coalesced in the main body and a large mass of air is generated, it is possible to prevent the air bubbles from flowing into the clean side chamber and eventually being sucked into the oil pump.

(2) In the oil strainer according to the present invention, the inflow member that guides the oil in the storage chamber into the dust side chamber is composed of a pipe member that penetrates the bottom of the main body and the partition wall, and the oil in the clean side chamber is led to the oil pump. The member is composed of a partition wall and a pipe member penetrating the upper part of the main body. According to the present invention, oil can be sucked from the bottom of the storage chamber by an oil pump provided on the upper side in the vertical direction of the oil strainer. Further, in the present invention, by penetrating the inflow member and the outflow member up and down, the oil strainer can be made more compact as compared with the case where the inflow member and the outflow member are penetrated left and right.

(3) In the oil strainer according to the present invention, a concave recess is formed in the bottom of the main body downward in the vertical direction, and the end portion of the partition wall and the outflow member, which is a pipe member penetrating the upper part of the main body, is formed in the recess. Provide to face. As a result, even if the oil level in the storage chamber drops, the oil pump can continue to suck up the oil in the clean side chamber.

(4) The oil strainer according to the present invention includes an air discharge member having an air discharge flow path that connects the upper part of the dust side chamber and the outside of the main body, an air discharge valve that opens and closes the air discharge flow path, and an air discharge valve. To be equipped. As described above, since the dust side chamber is arranged on the upper side in the vertical direction with respect to the clean side chamber, air bubbles contained in the oil in the main body collect in the upper part of the dust side chamber. On the other hand, according to the present invention, the air accumulated in the upper part of the dust side chamber can be discharged to the outside of the main body by opening the air discharge valve as appropriate.

(5) In the oil strainer according to the present invention, the air discharge valve includes a valve body that urges the valve body in the valve closing direction using the line pressure as a pilot pressure and an urging member that urges the valve body in the valve opening direction. To be equipped. Further, the elastic force of the urging member is set to be larger than the load due to the line pressure when the oil pump is stopped and smaller than the load due to the minimum line pressure when the oil pump is operating. Therefore, according to the present invention, since the air discharge flow path is closed by the line pressure while the oil pump is operating, air is not sucked from the outside to the inside of the main body through the air discharge flow path. Also, while the oil pump is stopped, the air discharge flow path is opened by the urging force of the urging member, so the air accumulated in the upper part of the dust side chamber is discharged to the outside of the main body via the air discharge flow path. Can be made to. When the air discharge flow path is opened, oil may flow into the dust side chamber from the outside of the main body, but this oil is supplied to the oil pump after passing through the filter medium, so this can be a problem. No.

It is an exploded perspective view which shows the structure of the lower part of the transmission which accommodates the oil strainer which concerns on one Embodiment of this invention. It is a partial breakthrough perspective view which broke a part of an oil strainer. It is sectional drawing of the oil strainer when the oil pump is operating. It is sectional drawing of the oil strainer when the oil pump is stopped.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view showing the configuration of the lower side of the transmission 1 for a vehicle accommodating the oil strainer 3 according to the present embodiment.

The transmission 1 includes a transmission mechanism (not shown) that shifts the driving force from the engine, which is a source of the driving force of the vehicle, a differential mechanism (not shown) that transmits the driving force shifted by the transmission mechanism to the axle, and the like. A power transmission mechanism and a casing 2 for accommodating these power transmission mechanisms are provided.

The casing 2 includes a casing main body 21 that covers the power transmission mechanism and constitutes the upper part of the transmission 1, and a dish-shaped oil pan 22 that forms the bottom of the transmission 1. The transmission 1 is mounted on a vehicle body (not shown) so that the oil pan 22 is arranged vertically downward with respect to the casing main body 21 as shown in FIG.

When the oil pan 22 is attached to the casing main body 21, an oil storage chamber 23 is formed between the oil pan 22 and the casing main body 21 as a space for collecting oil used as hydraulic oil or lubricating oil in the power transmission mechanism. Will be done.

In the oil storage chamber 23, an oil pump 31 driven by the crank shaft of the engine, sucking up the oil in the oil storage chamber 23 and supplying it to a plurality of mechanical parts constituting the power transmission mechanism, and the above-mentioned mechanical parts are supplied. A valve body 32 for controlling the oil pressure of the oil and an oil strainer 5 for removing foreign substances contained in the oil by filtering the oil sucked up by the oil pump 31 from the oil storage chamber 23 are provided. As shown in FIG. 1, the oil strainer 5 is provided on the lower side in the vertical direction, that is, on the oil pan 22 side with respect to the oil pump 31 and the valve body 32 so as not to suck air.

FIG. 2 is a partially cutaway perspective view in which a part of the oil strainer 5 is broken.
FIG. 3 is a cross-sectional view of the oil strainer 5 when the oil pump 31 is in operation.
FIG. 4 is a cross-sectional view of the oil strainer 5 when the oil pump 31 is stopped.

The oil strainer 5 includes a box-shaped main body 50 provided in the oil storage chamber 23, a filter medium 54 provided inside the main body 50, and tubular inflow pipes 61 and outflow pipes 62 provided in the main body 50. To be equipped.

The main body 50 is configured by combining a dish-shaped lower case 51 forming the bottom of the oil strainer 5, a dish-shaped upper case 52 forming the upper part of the oil strainer 5, and a plate-shaped separate plate 53. .. The lower case 51, the upper case 52, and the separate plate 53 are made of, for example, resin. As the filter medium 54, for example, a filter paper (for example, a non-woven fabric) having a rectangular shape in a plan view is used, but the present invention is not limited to this. For the filter medium 54, for example, a metal mesh may be used.

The main body 50 has a lower flange 511 and an outer peripheral edge of the upper case 52 formed on the outer peripheral edge of the lower case 51 with the edges of the separate plate 53 and the filter medium 54 sandwiched between the lower case 51 and the upper case 52. It is assembled by joining the upper flange 521 formed in the above surface by, for example, vibration welding. By assembling as described above, the dust side chamber 71 and the clean side chamber 72, which are two spaces, are partitioned inside the box-shaped main body 50 by using the separate plate 53 and the filter medium 54 as partition walls. More specifically, the dust side chamber 71 is partitioned by the upper case 52, the separate plate 53, and the filter medium 54, and the clean side chamber 72 is partitioned by the lower case 51, the separate plate 53, and the filter medium 54. .. Further, as shown in FIG. 2, when the oil strainer 5 is provided in the oil storage chamber 23, the dust side chamber 71 is arranged on the upper side in the vertical direction from the clean side chamber 72.

A through hole 512 through which the inflow pipe 61 is inserted and a concave recess 513 (see FIGS. 3 and 4) are formed in the lower case 51 facing the separate plate 53. .. As shown in FIGS. 3 and 4, the recess 513 is the lowest among the main bodies 50 in the state where the oil strainer 5 is provided in the oil storage chamber 23.

The separate plate 53 is formed with two through holes 531 and 532 through which the inflow pipe 61 and the outflow pipe 62 are inserted. The through hole 531 is formed in a portion of the separate plate 53 that faces the through hole 512 of the lower case 51 in the vertical direction. The through hole 532 is formed in a portion of the separate plate 53 that faces the recess 513 of the lower case 51 along the vertical direction.

A through hole 522 through which the outflow pipe 62 is inserted is formed in a portion of the upper case 52 that faces the recess 513 of the lower case 51 and the through hole 532 of the separate plate 53 in the vertical direction. Further, in the portion of the upper case 52 facing the filter medium 54, a tubular air discharge pipe 523 extending in the vertical direction is provided. Inside the air discharge pipe 523, an air discharge flow path 524 that communicates the upper part inside the dust side chamber 71 with the outside of the main body 50 is formed.

The inflow pipe 61 is a pipe member that connects the inside of the oil storage chamber 23 and the inside of the dust side chamber 71. The inflow pipe 61 extends along the vertical direction and is provided in the main body 50 so as to penetrate the lower case 51 and the separate plate 53. More specifically, the inflow pipe 61 has a suction port 61a on one end side facing into the oil storage chamber 23 outside the main body 50, and an outflow port 61b on the other end side facing into the dust side chamber 71. , It is inserted through the through hole 512 of the lower case 51 and the through hole 531 of the separate plate 53. Inside the inflow pipe 61, an oil flow path 61c that communicates the inside of the oil storage chamber 23 and the inside of the dust side chamber 71 is formed.

The outflow pipe 62 is a pipe member that connects the inside of the clean side chamber 72 and the oil pump 31. The outflow pipe 62 extends along the vertical direction and is provided in the main body 50 so as to penetrate the upper case 52 and the separate plate 53. More specifically, the outflow pipe 62 penetrates the upper case 52 so that the inflow port 62a on one end side of the outflow pipe 62 faces the inside of the clean side chamber 72 and the connection port 62b on the one end side faces the outside of the main body 50. It is inserted through the hole 522 and the through hole 532 of the separate plate 53. Inside the outflow pipe 62, an oil flow path 62c that communicates the inside of the clean side chamber 72 and the oil pump 31 is formed. As shown in FIG. 3, the inflow port 62a of the outflow pipe 62 faces the recess 313 formed in the lower case 51. Further, the connection port 62b of the outflow pipe 62 is connected to an oil passage 35 provided with an oil pump 31.

As shown in FIG. 3, the air discharge pipe 523 of the upper case 52 is provided with an air discharge valve 56 that opens and closes the air discharge flow path 524. The air discharge valve 56 urges the valve body 561 in the valve closing direction by using the line pressure, which is the hydraulic pressure in the valve body 561 provided in the air discharge flow path 524 and the oil passage 35 provided with the oil pump 31, as a pilot pressure. The valve body 562 is provided, and a spring 563 that urges the valve body 561 in the valve opening direction against the pilot pressure. As described above, the air discharge valve 56 opens and closes the air discharge flow path 524 according to the line pressure in the oil passage 35. More specifically, when the line pressure becomes higher than the predetermined pressure and the load acting on the valve body 561 due to this line pressure becomes larger than the elastic force of the spring 563, the valve body 561 is urged in the valve closing direction. Closes the air discharge flow path 524 (see FIG. 3). Further, when the line pressure becomes lower than the predetermined pressure and the load acting on the valve body 561 due to this line pressure becomes smaller than the elastic force of the spring 563, the valve body 561 is urged in the valve opening direction, whereby the air discharge flow path is urged. 524 is opened (see FIG. 4).

Further, the elastic force of the spring 563 is larger than the load due to the line pressure when the oil pump 31 is stopped (that is, when the engine is stopped) and is the minimum of the line pressure when the oil pump 31 is operating (that is, when the engine is operating). It is set to be smaller than the load due to pressure. Therefore, the air discharge valve 56 closes the air discharge flow path 524 while the oil pump 31 is operating, and opens the air discharge flow path 524 while the oil pump 31 is stopped.

Next, the flow of oil formed in the oil strainer 5 will be described with reference to FIGS. 3 and 4.

As shown in FIG. 3, when the oil pump 31 operates, the oil collected at the bottom of the oil storage chamber 23 is sucked up into the oil passage 35 via the oil strainer 5. At this time, the oil accumulated at the bottom of the oil storage chamber 23 flows vertically upward from the suction port 61a to the outflow port 61b along the inflow pipe 61, and flows into the dust side chamber 71. Further, the oil in the dust side chamber 71 passes through the filter medium 54 and flows to the clean side chamber 72 on the lower side in the vertical direction from the dust side chamber 71. Foreign matter contained in the oil is removed in the process of passing through the filter medium 54. Further, the oil in the clean side chamber 72 flows upward in the vertical direction from the inflow port 62a to the connection port 62b along the outflow pipe 62, and is sucked up by the oil pump 31. In this way, in the oil strainer 5, by arranging the clean side chamber 72 vertically lower than the dust side chamber 71, air bubbles contained in the oil do not collect in the clean side chamber 72, and the dust side chamber 71 It collects at the top. Further, when the oil pump 31 operates as described above, the air discharge valve 56 closes the air discharge flow path 524. Therefore, even if the oil level O of the oil in the oil storage chamber 23 becomes lower than that of the air discharge pipe 523, the air in the oil storage chamber 23 flows into the oil strainer 5 through the air discharge flow path 524. Nor. Therefore, a large mass of air is not sucked into the oil pump 31.

Next, as shown in FIG. 4, when the oil pump 31 is stopped, the air discharge valve 56 opens the air discharge flow path 524. Therefore, the air bubbles contained in the oil in the dust side chamber 71 and the clean side chamber 72 rise upward in the vertical direction and are discharged to the outside of the main body 50 via the air discharge flow path 524. At this time, the oil accumulated in the oil storage chamber 23 flows into the main body 50 via the air discharge flow path 524, so that the air accumulated in the main body 50 is replaced with the unfiltered oil accumulated outside the main body 50. NS. However, since this unfiltered oil first flows into the dust side chamber 71, it is not directly sucked into the oil pump 31 without being filtered.

According to the oil strainer 5 according to the present embodiment, the following effects are obtained.
(1) The oil strainer 5 includes a box-shaped main body 50, a filter medium 54 provided inside the main body 50, and a dust side chamber 71 in which the filter medium 54 is partitioned inside the main body 50 as a part of a partition wall. A clean side chamber 72, an inflow pipe 61 connecting the inside of the oil storage chamber 23 and the dust side chamber 71, and an outflow pipe 62 connecting the inside of the clean side chamber 72 and the oil pump 31 are provided. Further, in a state where the main body 50 is provided in the oil storage chamber 23, the dust side chamber 71 is arranged on the upper side in the vertical direction from the clean side chamber 72. As a result, air bubbles contained in the oil can be stored in the dust side chamber 71 and prevented from flowing into the clean side chamber 72. As a result, even when air bubbles contained in the oil are united in the main body 50 and a large mass of air is generated, it is possible to prevent the air bubbles from flowing into the clean side chamber 72 and eventually being sucked into the oil pump 31.

(2) In the oil strainer 5, the inflow pipe 61 for guiding the oil in the oil storage chamber 23 into the dust side chamber 71 is composed of a pipe member penetrating the lower case 51 and the separate plate 53, and is formed in the clean side chamber 72. The outflow pipe 62 that guides the oil to the oil pump 31 is composed of a pipe member that penetrates the separate plate 53 and the upper case 52. As a result, the oil can be sucked from the bottom of the oil storage chamber 23 by the oil pump 31 provided on the upper side of the oil strainer 5 in the vertical direction. Further, in the oil strainer 5, by penetrating the inflow pipe 61 and the outflow pipe 62 up and down, the oil strainer 5 can be made more compact as compared with the case where the inflow pipe 61 and the outflow pipe 62 are penetrated left and right.

(3) In the oil strainer 5, a concave recess 513 is formed in the lower case 51 downward in the vertical direction, and the inflow port 62a of the outflow pipe 62 penetrating the separate plate 53 and the upper case 52 faces the recess 513. To be provided. As a result, even when the oil level O of the oil in the oil storage chamber 23 drops, the oil pump 31 can continue to suck up the oil in the clean side chamber 72.

(4) The oil strainer 5 includes an air discharge pipe 523 formed with an air discharge flow path 524 that communicates the upper part of the dust side chamber 71 with the outside of the main body 50, and an air discharge valve that opens and closes the air discharge flow path 524. 56 and. As described above, since the dust side chamber 71 is arranged on the upper side in the vertical direction with respect to the clean side chamber 72, air bubbles contained in the oil in the main body 50 collect in the upper part of the dust side chamber 71. On the other hand, according to the oil strainer 5, the air accumulated in the upper part of the dust side chamber 71 can be discharged to the outside of the main body 50 by opening the air discharge valve 56 as appropriate.

(5) The air discharge valve 56 includes a valve body 562 that urges the valve body 561 in the valve closing direction using the line pressure as a pilot pressure, and a spring 563 that urges the valve body 561 in the valve opening direction. Further, the elastic force of the spring 563 is set to be larger than the load due to the line pressure when the oil pump 31 is stopped and smaller than the load due to the minimum line pressure when the oil pump 31 is operating. As a result, while the oil pump 31 is operating, the air discharge flow path 524 is closed by the line pressure, so that air is not sucked from the outside to the inside of the main body 50 through the air discharge flow path 524. Further, while the oil pump 31 is stopped, the air discharge flow path 524 is opened by the urging force of the spring 563, so that the air accumulated in the upper part of the dust side chamber 71 is passed through the air discharge flow path 524 to the main body 50. Can be discharged to the outside of. When the air discharge flow path 524 is opened, oil may flow into the dust side chamber 71 from the outside of the main body 50, but this oil is supplied to the oil pump 31 after passing through the filter medium 54. It doesn't matter.

Although one embodiment of the present invention has been described above, the present invention is not limited to this. Within the scope of the gist of the present invention, the detailed configuration may be changed as appropriate.

1 ... Transmission 2 ... Casing 21 ... Casing body 22 ... Oil pan 23 ... Oil storage chamber (storage chamber)
31 ... Oil pump 35 ... Oil passage 5 ... Oil strainer 50 ... Main body 51 ... Lower case (bottom)
513 ... Recess 52 ... Upper case (upper)
523 ... Air discharge pipe (air discharge member)
524 ... Air discharge flow path 53 ... Separate plate 54 ... Filter media 56 ... Air discharge valve 561 ... Valve body 562 ... Valve body 563 ... Spring (urgency member)
61 ... Inflow pipe (inflow member)
61a ... Mouth (one end)
61b ... Outlet (other end)
62 ... Outflow pipe (outflow member)
62a ... Inflow port (one end)
62b ... Connection port (other end)
71 ... Dust side room 72 ... Clean side room

Claims (4)

An oil strainer that filters the oil supplied from the storage chamber to the mechanical parts of the vehicle.
The box-shaped main body provided in the storage chamber and
With the filter medium provided inside the main body,
A dust side chamber and a clean side chamber, which are partitioned inside the main body by using the filter medium as a part of a partition wall,
An inflow member connecting the storage chamber and the dust side chamber,
An outflow member for connecting the clean side chamber and the oil pump is provided.
When the main body is provided in the storage chamber, the dust side chamber is arranged vertically above the clean side chamber .
The inflow member is a pipe member that penetrates the bottom of the main body and the partition wall, one end of which faces the storage chamber and the other end of which faces the dust side chamber.
The oil strainer is characterized in that the outflow member is a pipe member that penetrates the upper part of the main body and the partition wall, one end of which faces the clean side chamber and the other end of which is connected to the oil pump. A concave recess is formed on the bottom in the vertical direction.
The end of the outlet member, the oil strainer as claimed in claim 1, characterized in that facing the recess. An oil strainer that filters the oil supplied from the storage chamber to the mechanical parts of the vehicle.
The box-shaped main body provided in the storage chamber and
With the filter medium provided inside the main body,
A dust side chamber and a clean side chamber, which are partitioned inside the main body by using the filter medium as a part of a partition wall,
An inflow member connecting the storage chamber and the dust side chamber,
An outflow member that connects the clean side chamber and the oil pump,
An air discharge member having an air discharge flow path that communicates the upper part of the dust side chamber with the outside of the main body.
An air discharge valve that opens and closes the air discharge flow path is provided.
An oil strainer characterized in that, when the main body is provided in the storage chamber, the dust side chamber is arranged on the upper side in the vertical direction with respect to the clean side chamber. The air discharge valve is a valve that urges the valve body in the valve closing direction by using a valve body provided in the air discharge flow path and a line pressure which is a hydraulic pressure in an oil passage provided with the oil pump as a pilot pressure. A body and an urging member for urging the valve body in the valve opening direction are provided.
The elastic force of the urging member is set to be larger than the load due to the line pressure when the oil pump is stopped and smaller than the load due to the minimum pressure of the line pressure while the oil pump is operating. The oil strainer according to claim 3 , wherein the oil strainer is characterized in that.

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