JP6454997B2 - Reservoir tank - Google Patents

Description

  The present invention relates to a reservoir tank.

  Conventionally, as a device using a fluid pressure actuator, for example, there is a hydraulic power steering device described in Patent Document 1. The hydraulic power steering device disclosed in Patent Document 1 assists the steering operation of the driver (steering assist) using hydraulic oil. This type of hydraulic power steering apparatus is provided with a reservoir tank for storing hydraulic oil circulating in the apparatus. The hydraulic oil stored in such a reservoir tank flows out from the outlet through the outflow pipe into the hydraulic power steering apparatus, circulates in the apparatus, returns to the tank from the inlet through the inflow pipe. In such a reservoir tank, a mesh-like filter is provided so as to partition the outflow port and the inflow port so as to try to remove foreign matters mixed in the hydraulic oil.

JP 2012-148700 A

  The size of the foreign matter mixed in the hydraulic oil varies in size, and it can be said that the filter mesh size should be reduced in order to effectively remove them. However, if the filter mesh size is too small, resistance when sucking hydraulic oil from the tank may increase, or the mesh may be clogged. For this reason, there is a limit in reducing the mesh size, and there is a limit in removing foreign matters mixed in the hydraulic oil in the filter. For this reason, there is a foreign matter that passes through without being removed by the filter, and there is a problem that such a foreign matter circulates in the apparatus again. Such a problem is not limited to a device using hydraulic oil, and may occur in a device using a fluid.

  This invention is made | formed in view of such a situation, The objective is to provide the reservoir tank which can suppress the outflow of the foreign material to an outflow port.

A reservoir tank that solves the above problems includes a bottomed cylindrical tank body that can store fluid, an inflow pipe that is connected from the outside of the tank body to an inflow port that allows the fluid to flow into the tank body, and a fluid from inside the tank body. is connected from the outside to the tank body has an outlet for flow out and an outflow pipe. The reservoir tank is provided with a filter capable of removing foreign substances from the fluid between the inlet and the outlet in the tank body. When the increase side increase or decrease direction of the fluctuation surface of the fluid in the reservoir tank to the upper, the outlet pipe extends upward from the bottom of the tank body, the及department internal outlet pipe to the inside of the tank body And the outlet is formed at the tip of the internal outlet pipe. Further, the outlet is formed above the upper end of the inlet.

  According to the above configuration, the fluid returned from the inlet to the inside of the tank body through the inlet pipe comes into contact with the inner outlet pipe with high probability, and direct inflow to the inner outlet pipe, that is, the outlet is suppressed. It becomes like this. Further, the fluid flowing so as to hit the internal outflow pipe has an effect of separating foreign substances from the fluid flow. For this reason, the outflow to the outflow port of the foreign material which cannot be removed with a filter can be suppressed.

  In such a reservoir tank, it is preferable that a trapping portion capable of trapping foreign matter by passing the fluid that has passed through the filter is provided between the filter and the outlet and around the inner outlet pipe.

  According to the above configuration, even if there is a foreign matter that could not be completely removed by the filter, the fluid containing such a foreign matter contributes to the removal by passing through the capturing part. As described above, since the direct inflow of the fluid returned from the inlet to the inside of the tank body through the inlet pipe into the tank body, that is, the outlet, is suppressed, the foreign matter once trapped by the trapping portion is suppressed. Outflow to the outlet can be suppressed.

  By the way, when the flow of the fluid stops, foreign matters that could not be removed by the filter start to float, especially between the filter and the outlet, and these foreign matters flow into the outlet as the fluid flows again. There is a possibility of going. In that respect, according to the above configuration, the foreign matter once captured by the capturing unit between the filter and the outlet is prevented from floating even if the flow of the fluid is stopped. Therefore. Outflow of foreign matter to the outlet can be suppressed.

  Such a capturing part may be a magnet or a plurality of wall parts erected in a direction that blocks the flow of fluid. That is, when the capturing part is a magnet, iron powder or the like is removed by being attracted to the magnet among foreign substances that cannot be completely removed by the filter. As described above, since the direct inflow of the fluid returned from the inlet to the inside of the tank main body through the inlet pipe, that is, the outlet is suppressed, the outlet of the foreign matter adsorbed by the trapping portion The outflow to can be suppressed.

  On the other hand, when the capturing part is a plurality of wall parts, the foreign matter that cannot be removed by the filter enters between the wall parts and is separated from the fluid flow. As described above, since the direct inflow of the fluid returned from the inlet to the inside of the tank body through the inlet pipe into the tank body, that is, the outlet, is suppressed, the foreign substance that has entered the trapping section is discharged to the outlet. Can be suppressed.

  According to the present invention, the outflow of foreign matter to the outlet can be suppressed.

The figure which shows schematic structure of a hydraulic power steering apparatus. Sectional drawing which shows a reservoir tank. III-III sectional view taken on the line of FIG. (A), (b) is a figure which shows the capturing part in another example. (A), (b) is a figure which shows the outflow port in another example. The figure which shows schematic structure of the hydraulic power steering apparatus in another example.

Hereinafter, an embodiment of the reservoir tank will be described.
As shown in FIG. 1, the reservoir tank 10 is used for storing hydraulic oil (oil) used in the hydraulic power steering apparatus 1, for example. Here, first, the hydraulic power steering apparatus 1 will be described.

  The hydraulic power steering apparatus 1 includes a steering wheel 2 operated by a driver and a steering shaft 3 to which the steering wheel 2 is fixed. The hydraulic power steering apparatus 1 includes a rack shaft 5 that reciprocates in the axial direction according to the rotation of the steering shaft 3, and a substantially cylindrical rack housing 6 through which the rack shaft 5 is reciprocally movable. The steering shaft 3 is configured by connecting a column shaft, an intermediate shaft, and a pinion shaft in order from the steering wheel 2 side. The rack shaft 5 is made of a metal such as iron.

  The rack shaft 5 and the steering shaft 3 (pinion shaft) are arranged in the rack housing 6 with a predetermined crossing angle, and rack teeth 5a formed on the rack shaft 5 and pinion teeth 3a formed on the steering shaft 3 are formed. A meshed rack and pinion type steering gear 11 is configured. Tie rods 12 are connected to both ends of the rack shaft 5, and steered wheels 13 are connected to each other via the tie rods 12.

  In the hydraulic power steering device 1, the rotation of the steering shaft 3 accompanying the steering operation of the driver is converted into the axial movement of the rack shaft 5 by the steering gear 11, and this axial movement is converted to the left and right steered wheels 13 via the tie rods 12. And the turning angle of the steered wheels 13, that is, the traveling direction of the vehicle is changed.

  In addition, the hydraulic power steering apparatus 1 includes a hydraulic cylinder 21 that generates an assist force that assists a driver's steering operation, and an electric pump 22 that supplies hydraulic oil to the hydraulic cylinder 21. The hydraulic power steering device 1 includes a valve device 23 that controls supply / discharge of hydraulic oil to / from the hydraulic cylinder 21 and a reservoir tank 10 that reserves (stores) hydraulic oil supplied / discharged to / from the hydraulic cylinder 21 by the electric pump 22. Prepare. The electric pump 22 is electrically driven and obtains driving force (driving power) from a battery 45 such as a secondary battery mounted on the vehicle.

  The hydraulic cylinder 21 includes a cylindrical cylinder tube 31 configured by a part of the rack housing 6. That is, the rack shaft 5 is inserted into the cylinder tube 31 so as to be able to reciprocate. The cylinder tube 31 is made of a metal such as iron. The hydraulic cylinder 21 includes a piston 34 that divides the inside of the cylinder tube 31 into a first hydraulic chamber 32 and a second hydraulic chamber 33, and the piston 34 is integrally fixed to the rack shaft 5 so as to be movable in the axial direction. The piston 34 is made of a metal such as iron.

  Further, the valve device 23 is provided with a supply port 51, a discharge port 52, a first supply / discharge port 53, and a second supply / discharge port 54. The supply port 51 is connected to the discharge port of the electric pump 22 via the supply oil passage 55. The discharge port 52 is connected to the reservoir tank 10 via a discharge oil passage 56. The first supply / discharge port 53 is connected to the first hydraulic chamber 32 via the first supply / discharge oil passage 57, and the second supply / discharge port 54 is connected to the second hydraulic pressure via the second supply / discharge oil passage 58. Connected to chamber 33. The suction port of the electric pump 22 is connected to the reservoir tank 10 via a suction oil passage 59.

  In the hydraulic power steering device 1, the hydraulic oil sucked (intaken) from the reservoir tank 10 by the electric pump 22 is supplied to the valve device 23 via the intake oil passage 59 and the supply oil passage 55. The hydraulic oil supplied to the valve device 23 is supplied to the first and second hydraulic chambers 32 and 33 via one of the first and second oil supply / discharge oil passages 57 and 58 according to the steering operation of the driver. Supplied to either one. As a result, the corresponding hydraulic chamber is filled with the hydraulic oil and pressurized (the hydraulic pressure increases). At this time, the hydraulic oil is discharged from the other one of the first and second hydraulic chambers 32, 33, and the hydraulic oil is discharged from the other of the first and second oil supply / discharge oil passages 57, 58, the valve device 23 and the discharge oil passage. It is discharged to the reservoir tank 10 through 56. As a result, the hydraulic oil is discharged from the corresponding hydraulic chamber and the pressure is reduced (the hydraulic pressure is lowered). As a result, a hydraulic pressure difference is generated between the first hydraulic chamber 32 and the second hydraulic chamber 33, and the rack shaft 5 moves in the axial direction together with the piston 34 based on the hydraulic pressure difference. Assisted.

Next, the configuration of the reservoir tank 10 will be described.
As shown in FIG. 2, the reservoir tank 10 includes a bottomed cylindrical tank body 10a having a circular inflow port 10b, an outflow port 10c, and an injection port 10d that communicate with the outside. The tank body 10a is made of a resin material. The reservoir tank 10 is installed with respect to the hydraulic power steering apparatus 1, that is, the vehicle so that the inlet 10b opens in a substantially horizontal direction and the outlet 10c and the inlet 10d open in a substantially vertical direction.

  A cylindrical inflow pipe 24 is connected to the inflow port 10b in the horizontal direction, and a discharge oil passage 56 is connected through the inflow pipe 24. A cylindrical outflow pipe 25 is connected to the outflow port 10 c in the vertical direction (downward), and a suction oil passage 59 is connected through the outflow pipe 25. A cylindrical strainer 26 is fitted into the inlet 10d from the vertical direction (above), and the hydraulic oil can be replenished from the outside via the strainer 26. The strainer 26 is made of resin or metal material. The injection port 10d is sealed from the vertical direction (above) by a circular cap 10e.

  The hydraulic oil is stored in the tank main body 10f of the tank main body 10a, and the hydraulic oil is sucked and discharged from the tank main body 10f to the outflow pipe 25 through the outflow port 10c, and from the inflow pipe 10 through the inflow pipe 24. The hydraulic oil flows into 10f and returns.

  2 and 3, the inflow port 10b and the outflow port 10c have an extension of the center of the inflow port 10b intersecting the center of the tank body interior 10f, and the center of the outflow port 10c is the center of the tank body interior 10f. Formed to match.

  Further, the outflow pipe 25 has an internal outflow pipe 25a extending to the tank body inside 10f. The internal outflow pipe 25a extends upward from the bottom of the tank body 10a, and the outflow port 10c is located at the tip thereof. The position of the outlet 10c is above the upper end of the inlet 10b by a distance L, and realizes an arrangement that abuts against the side wall 25b of the internal outlet pipe 25a when the inlet 10b is extended. Here, the upper side means an increase side in the increase / decrease direction of the hydraulic oil fluctuation surface F (liquid level), and the outlet 10c is on the increase side of the hydraulic oil fluctuation surface F with respect to the inlet 10b (upper end). Means to be located.

  An annular filter 27 is provided around the internal outlet pipe 25a. The filter 27 is made of a resin or metal material configured in a mesh shape, and has a function of removing (filtering) foreign matters such as dust and metal wear powder that are mixed when hydraulic fluid passes through the mesh. A partition plate 27c having a bowl-like cross section is fixed above the filter 27 and in the middle of the tank body inside 10f in the vertical direction. The tip of the strainer 26 is fitted into the center of the partition plate 27c.

  A packing 27a made of a resin material is interposed between the lower end of the filter 27 and the bottom of the tank body interior 10f. Between the upper end of the filter 27 and the partition plate 27c, a packing 27b made of a resin material that seals between them is interposed. A trap 28 made of a magnet is fixed between the side wall 25b of the inner outlet pipe 25a and the filter 27 (packing 27a) in the radial direction and on the bottom of the tank body 10f. The capturing unit 28 has a function of adsorbing, that is, capturing and removing metal foreign matters such as iron powder mixed by passing hydraulic oil.

  As shown in FIGS. 2 and 3, the tank body interior 10 f has a filter 27 as a boundary, an upstream space 29 a where hydraulic oil before passing through the filter 27 is stored, and a downstream where hydraulic oil after passing through the filter 27 is stored. It is divided into a space 29b.

  The hydraulic oil stored in the upstream space 29a is before foreign matter removal by the filter 27 and has a high possibility of foreign matter mixing. The hydraulic oil stored in the downstream space 29b is after foreign matter removal by the filter 27 and further after foreign matter removal by the capturing unit 28, and is less likely to be mixed with foreign matter than before foreign matter removal by the filter 27.

According to the reservoir tank 10 described above, the following operations and effects (1) to (4) are achieved.
(1) As shown in FIGS. 2 and 3, the hydraulic oil that has flowed into the tank main body 10 f flows through the upstream space 29 a through the flow path indicated by the arrow R <b> 1 and passes through the filter 27.

  In this case, the hydraulic oil passes through the filter 27 from the middle of circulating around the upstream space 29a in addition to the flow path indicated by arrow R1 passing through the inlet 10b and passing through the filter 27 as it is, or further circulating around the inlet. It passes through the filter 27 from the substantially opposite side of 10b, or passes through the filter 27 at any one of the timings described above after one round. In the hydraulic oil that passes through the filter 27, foreign matters are removed by the filter 27 during the passage, while foreign matters smaller than the mesh of the filter 27 are not removed but enter the downstream space 29b.

  The hydraulic oil that has passed through the filter 27 strikes the side wall 25b of the internal outlet pipe 25a while passing through the flow path indicated by the arrow R2. In this case, since the internal outflow pipe 25a extends above the upper end of the inflow port 10b, the hydraulic oil passes through the trap 28 and strikes the internal outflow pipe 25a with a high probability. As such a flow path, there is a flow path that hits the internal outflow pipe 25a and passes over the capturing portion 28 in addition to the flow path indicated by the arrow R2. Then, the hydraulic oil flows through the downstream space 29b, is sucked from the outlet 10c through the flow path indicated by the arrow R3, and flows out from the tank body inside 10f.

  For this reason, according to the present embodiment, the hydraulic oil returned from the inlet 10b to the tank body inside 10f through the inlet pipe 24 comes into contact with the inner outlet pipe 25a with high probability, and the inner outlet pipe 25a, That is, direct inflow to the outlet 10c is suppressed.

  Further, as described above, the hydraulic oil flowing so as to hit the internal outflow pipe 25a also has an effect of removing foreign matters that could not be completely removed by the filter 27 by passing over the capturing portion 28 from the flow of the hydraulic oil.

  In this embodiment, metal wear powder generated by the rack shaft 5 reciprocating in the cylinder tube 31 is assumed as a foreign matter that has not been completely removed by the filter 27, that is, a foreign matter smaller than the mesh. Since the rack shaft 5, the cylinder tube 31, and the piston 34 are made of metal such as iron, when the rack shaft 5 reciprocates in the cylinder tube 31, the wear on the rack shaft 5 and the cylinder tube 31 and the cylinder tube 31 and the piston 34 are increased. Wear of metal generates metal wear powder. The abrasion powder generated in this way may circulate through various oil passages, various ports, the reservoir tank 10, the electric pump 22, and the like in the hydraulic power steering apparatus 1 through supply and discharge of hydraulic oil. In addition, metal powder adhered to various oil passages and various ports at the time of assembly, and metal wear powder generated based on the operation of the valve device 23 are assumed.

In the present embodiment, the outflow of foreign matters that cannot be completely removed by the filter 27 to the outlet 10c can be suppressed.
(2) The flow of hydraulic oil may carry away foreign matter that has already been removed by the capture unit 28 when passing over the capture unit 28. In this respect, in this embodiment, as described above, since the inflow of the hydraulic oil directly to the outlet 10c is suppressed, the trapping section 28 has already captured the hydraulic oil flow when it passes over the trapping section 28. Even if the removed foreign matter is taken away, the foreign matter taken away on the way to the outlet 10c may be detached from the flow. Therefore, the outflow of the foreign matter once captured by the capturing unit 28 to the outlet 10c can be suppressed.

  (3) By the way, when the flow of hydraulic oil stops, foreign matter that could not be removed by the filter 27 starts to float especially between the filter 27 and the outlet 10c, and the hydraulic oil flows out again as such foreign matter. As a result, there is a possibility of flowing into the outlet 10c. In this respect, according to the present embodiment, the foreign matter once captured by the capturing unit 28 between the filter 27 and the outlet 10c can be prevented from floating even if the flow of hydraulic oil stops. Therefore, the outflow of foreign matter to the outlet 10c can be suppressed.

  (4) The hydraulic oil stored in the tank body 10 a is sucked from the outlet 10 c through the electric pump 22. The electric pump 22 of the present embodiment is an electric pump 22 that has a relatively small driving power because it is electrically driven based on a battery 45 mounted on the vehicle. Then, in particular, the contamination of foreign matters in the hydraulic oil can have a great influence on the operation. For example, when foreign matter mixed in the hydraulic oil enters the electric pump 22, it may be caught between rotating parts of the pump. The foreign matter sandwiched between the rotating parts in this way becomes a resistance during driving, and if the electric pump 22 has a relatively small driving power as in the present embodiment, it can cause the driving to stop. In that respect, if the outflow of foreign matter to the outlet 10c can be suppressed, the operation can be stabilized even with the electric pump 22 having relatively small driving power as in the present embodiment.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
-The configuration of the capturing unit can be changed as long as it is possible to capture the foreign matter and allow it to be separated from the flow of the working oil by passing the working oil. For example, as shown in FIGS. 4 (a) and 4 (b), a capturing unit 100 in which a plurality of wall portions 100a are erected on a base 100b may be provided instead of the capturing unit 28 made of a magnet. The plurality of wall portions 100a are erected in the vertical direction with respect to the hydraulic oil flowing in the direction that blocks the flow of hydraulic oil returned from the inlet 10b, that is, in the horizontal direction. In such a capturing part 100, the foreign matter that cannot be completely removed by the filter 27 enters between the wall part 100a and the wall part 100a so as to be separated from the flow of hydraulic oil. And as explained in the above embodiment, since the direct inflow of the hydraulic oil through the inflow pipe 24 to the internal outflow pipe 25a of the hydraulic oil returned from the inflow port 10b to the tank body inside 10f, that is, the outflow port 10c, is suppressed. The outflow of the foreign matter that has entered the capturing unit 100 to the outflow port 10c can be suppressed. In addition, in such a capture part 100, the magnitude | size of the foreign material which can be removed can be adjusted by adjusting the clearance gap between the wall parts 100a. In addition, such a capturing portion can be realized by standing upright at random.

  -The structure of the outflow pipe | tube 25 may be changed if the relationship formed in the increase side of the increase / decrease direction of the fluctuation | variation surface F of hydraulic oil with respect to the inflow port 10b is ensured with respect to the inflow port 10c. For example, as shown in FIGS. 5A and 5B, a flange portion 101 may be provided on the periphery of the outlet 10c. According to this configuration, the hydraulic oil that has struck the side wall 25b of the internal outlet pipe 25a can be prevented from flowing out directly to the outlet 10c by the flange portion 101, and to the outlet 10c for foreign matters that cannot be completely removed by the filter 27. The effect which suppresses the outflow of can be heightened. Such a flange portion 101 is constituted by a member different from the tank body 10a. Further, with the internal outlet pipe 25a as a separate member, the diameter of the side wall 25b may be increased as the side wall 25b moves upward from below, or the side wall 25b itself may be formed in a flange shape. Even in this case, the same effect as the flange portion 101 is obtained.

  The capturing unit 28 can be provided between the inlet 10 b and the filter 27. In this case, metal wear powder and the like are removed before passing through the filter 27, but as in the above-described embodiment, the outflow of foreign matter that cannot be completely removed by the filter 27 to the outlet 10c can be suppressed. . It is preferable that the filter 27 in such another example is formed in a dome shape so as to surround the outflow port 10c or directly attached to the outflow port 10c.

  -Even if the arrangement of the inflow pipe 24 and the outflow pipe 25 is changed, as long as the relationship that the outflow port 10c is formed on the increasing side in the increase / decrease direction of the hydraulic oil fluctuation surface F with respect to the inflow port 10b is secured. Good. For example, both the inflow pipe 24 and the outflow pipe 25 may be arranged in the horizontal direction. In this case, the outflow pipe 25 is connected to the tank main body 10a from the horizontal direction, and the internal outflow pipe 25a is connected to the tank main body 10f. It should just be extended upwards.

  The internal outflow pipe 25 a may be provided at a position shifted from the extension of the inflow pipe 24. Even in this case, the hydraulic oil returned from the inlet 10b to the tank main body 10f can be abutted against the internal outlet pipe 25a. Preferably, the shape of the tank body interior 10f and the shape and arrangement of the filter 27 are devised so as to increase the probability of abutting against the internal outflow pipe 25a.

  The reservoir tank 10 may not have a configuration corresponding to the capturing unit. Even in this case, if the hydraulic oil returned from the inlet 10b to the tank body interior 10f can be brought into contact with the internal outlet pipe 25a, foreign matter that cannot be completely removed by the filter 27 has an effect of detaching from the hydraulic oil flow. For this reason, this another example has the effect of suppressing the outflow of foreign matter that cannot be completely removed by the filter 27 to the outlet 10c, as in the above embodiment.

A pump driven by an engine mounted on a vehicle can be used as a drive source for circulating hydraulic oil.
-Although the said embodiment demonstrated the application example to the hydraulic power steering apparatus 1 as an example using hydraulic fluid as a fluid, it can also apply to the brake device of a vehicle, or a vehicle height adjustment apparatus, for example. In addition, as an example in which water is used as a fluid, the present invention can be applied to a cooling device for a vehicle engine that circulates cooling water.

  As the hydraulic power steering device 1, an RBS type (recirculating ball screw type) steering gear may be employed. As shown in FIG. 6, the RBS type steering gear 60 is connected to the reservoir tank 10 via a supply oil passage 64 (suction oil passage 65) and a discharge oil passage 66. The steering gear 60 converts the rotational motion of the steering shaft 3 into the left-right swing motion of the pitman arm 61. The swing of the pitman arm 61 is transmitted to the left and right steered wheels 63 via the left and right tie rods 62. The steering gear 60 is provided with a ball screw mechanism having a ball nut fitted therein via a large number of balls that can be circulated to the ball screw portion. In such a ball screw mechanism, since the ball screw portion and the ball are each made of a metal such as iron, metal wear powder is generated by the wear. That is, in the RBS type steering gear 60, metal friction powder is generated from the ball screw mechanism, and a larger amount of metal wear powder can be generated than the rack and pinion type steering gear 11. For this reason, when the steering gear 60 is employed in the hydraulic power steering apparatus 1, it is more effective to suppress the outflow of foreign matter that cannot be completely removed by the filter 27 to the outlet 10c.

Next, a technical idea that can be grasped from the above-described embodiment and another example (modification) will be additionally described below.
(A) The fluid stored in the tank body is sucked from the outlet through an electric pump. Since the electric pump is an electric drive, if the electric pump has a small driving power, the mixing of foreign substances in the fluid may have a great influence on the operation. For example, when a foreign substance mixed in the fluid enters the electric pump, it may be caught between rotating parts of the pump. The foreign matter sandwiched between the rotating parts in this way becomes a resistance during driving, and can be a cause of stopping the driving particularly when the electric pump has a small driving power. In that regard, if the outflow of foreign matter to the outlet can be suppressed, the operation can be stabilized even with an electric pump with low driving power.

  DESCRIPTION OF SYMBOLS 10 ... Reservoir tank, 10a ... Tank main body, 10b ... Inflow port, 10c ... Outlet, 10f ... Inside tank main body, 22 ... Electric pump, 24 ... Inflow pipe, 25 ... Outflow pipe, 25a ... Internal outflow pipe, 27 ... Filter 28 ... Capture part, 100 ... Capture part, 100a ... Wall part, 100b ... Base.

Claims (4)

A bottomed cylindrical tank body capable of storing a fluid, an inlet pipe connected from the tank body external to the inlet for flowing the fluid into the tank body inside, an outlet for discharging the fluid from the interior of the tank body in the a tank body in the outflow pipe connected from the outside, a reservoir tank removable filter foreign matter from said fluid between said inlet and said outlet is provided in the interior of the tank body has ,
When the increase side in the increase / decrease direction of the fluctuation surface of the fluid in the reservoir tank is upward,
The outflow tube extends upward from the bottom of the tank body has an及department internal outlet pipe to the inside of the tank body, the outlet port is formed at the tip of the internal outlet pipe,
The reservoir tank, wherein the outlet is formed above an upper end of the inlet.   2. The capture unit according to claim 1, wherein a capture unit is provided between the filter and the outflow port and around the internal outflow pipe so that the fluid that has passed through the filter can capture foreign matter. Reservoir tank.   The reservoir tank according to claim 2, wherein the capturing unit is made of a magnet.   3. The reservoir tank according to claim 2, wherein the capturing section includes a plurality of wall sections standing in a direction that blocks the flow of the fluid.