JP2009262603A - Reservoir tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reservoir tank for securing efficient volume by sufficiently reducing invalid volume without increasing a tank height. <P>SOLUTION: The reservoir tank for storing in a suppliable state a liquid operating fluid supplied to a hydraulic circuit 1 carried in a vehicle comprises a lower tank part 11 partitioning a vertical direction lower side portion 13a of a reservoir chamber 13 for storing the operating fluid, and having a supply port 11a formed to supply the operating fluid to the hydraulic circuit 1, and an upper tank part 12 partitioning a vertical direction upper side portion 13b of the reservoir chamber 13 so as to have a large horizontal section area than the vertical direction lower side portion 13a and having an injection port 12a formed to allow the operating fluid to be injected into the reservoir chamber 13. The center G2 in the vehicle longitudinal direction of the reservoir chamber 13 in the upper tank part 12 is located on the rear side of the vehicle rather than the center G1 in the vehicle longitudinal direction of the reservoir chamber 13 in the lower tank part 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reservoir tank, and more particularly to a reservoir tank that stores a liquid working fluid supplied to the fluid pressure circuit in a fluid pressure circuit mounted on a vehicle so as to be supplied.

  In vehicles such as automobiles, fluid pressure actuated devices, for example, those equipped with a hydraulically actuated power steering device are often used. The fluid pressure control circuit of such devices is a liquid working fluid. A reservoir tank is provided for storing hydraulic oil so that it can be stably supplied. This reservoir tank is generally formed in a cylindrical shape in consideration of changes in the tank support posture and liquid level fluctuations, and has an inlet with a cap having a breather function and a supply for fluid supply connected to a fluid pressure circuit. And have a mouth. Further, in order to prevent air from entering the supply port, a supply port that does not come out from the liquid level into the gas phase in the tank is arranged, and a minimum liquid amount (invalid volume) is set. Furthermore, the maximum liquid amount that can be stored is set such that the liquid level does not reach the cap when the liquid level of the working fluid stored in the tank changes. Therefore, the difference between the maximum liquid amount and the minimum liquid amount in the reservoir tank is the effective volume of the reservoir tank.

  As a conventional reservoir tank of this type, for example, a cover that is formed in a cup shape that partitions the suction port of the inner bottom portion and the space in the tank and that connects the suction port and the space in the tank through a plurality of openings formed in the peripheral portion. It is known that air is prevented from being caught by dispersing the negative pressure of the working fluid generated in the vicinity of the suction port (see, for example, Patent Document 1).

  In addition, a pipe hole is formed in the inclined bottom wall of the tank body made of synthetic resin, and a non-rotating portion of a flanged bush is attached to the hole, and the seal and the loosening prevention elastic member are sandwiched between them. There has been known one in which a bush is easily and reliably attached to a tank body (see, for example, Patent Document 2).

  Further, in a reservoir tank having a supply port to the pump side and a return port from the pump side at the lower part of the tank body long in the vertical direction, a pressure case forming a pressure chamber with a filter leading to the return port, and the pressure case And a nozzle that protrudes from the pressure chamber toward the supply port and discharges the hydraulic fluid from the pressure chamber into the supply port to prevent cavitation (for example, see Patent Document 3).

In addition, an opening with a filter that is inclined with respect to the horizontal plane on the bottom wall side of the tank body, and an oil outflow chamber and an oil outlet that allow oil to flow out of the tank through the opening are provided. There is also known one that prevents mixing (for example, see Patent Document 4).
JP 2003-118608 A Japanese Utility Model Publication No. 06-28425 JP-A-11-255133 Japanese Utility Model Publication No. 05-19602

  However, in the conventional reservoir tank as described above, the ineffective volume of the tank is a force that greatly tilts the liquid surface, so-called G (gravity acceleration when the road surface is inclined, vehicle acceleration or deceleration, lateral acceleration, etc.) Although it is desirable to lengthen the tank body in the vertical direction to reduce the ineffective volume and increase the effective volume, there is an upper limit on the height of the tank from the standpoint of limiting the mounting space and securing the tank strength. In the case of a vehicle equipped with a hydraulic actuator that consumes a large amount of liquid, the ineffective volume increases due to the need to increase the horizontal cross-sectional area in the tank. There was a problem of becoming a tank.

  In addition, a cylindrical tank is often provided to prevent air from entering the supply port. However, if the ineffective volume is increased in that case, the mounting weight is increased.

  The present invention has been made to solve the above-described conventional problems. A reservoir tank that can sufficiently reduce the ineffective volume without increasing the tank height and secure an efficient volume is provided. It is intended to provide.

  In order to achieve the above object, a reservoir tank according to the present invention is (1) a reservoir tank that stores liquid working fluid supplied to the fluid pressure circuit in a fluid pressure circuit mounted on a vehicle so as to be able to be supplied. A lower tank portion that defines a lower portion in the vertical direction of the storage chamber that stores the working fluid, and that is formed with a supply port that supplies the working fluid to the fluid pressure circuit, and an upper portion in the vertical direction of the storage chamber. An upper tank portion that defines a side portion so that a horizontal cross-sectional area is larger than that of the lower portion in the vertical direction, and is formed with an inlet capable of injecting the working fluid into the storage chamber. The center in the vehicle front-rear direction of the storage chamber in the tank portion is located on the vehicle rear side from the center in the vehicle front-rear direction of the storage chamber in the lower tank portion.

  With this configuration, the volume of the lower tank portion is suppressed, and the minimum amount of liquid (hereinafter also referred to as an invalid volume) required to position the supply port in the liquid when the liquid level is inclined due to sudden braking or the like is sufficient. On the other hand, the volume of the upper tank portion is sufficiently secured, and the required tank capacity can be efficiently secured. In addition, since the vehicle longitudinal center of the storage chamber in the upper tank portion is located on the vehicle rear side from the vehicle longitudinal center of the storage chamber in the lower tank portion, the liquid at the time of sudden braking or the like where the liquid level inclination becomes large The amount of surface movement can be suppressed, and the effect of reducing the ineffective volume can be secured.

  In the reservoir tank described in (1) above, (2) the depth dimension in the vehicle front-rear direction of the storage chamber in the upper tank portion is greater than the depth dimension in the vehicle front-rear direction of the storage chamber in the lower tank portion. Larger is preferred.

  With this configuration, it is possible to suppress the total height of the reservoir tank and sufficiently suppress the ineffective volume while sufficiently securing the volume of the upper tank portion.

  In the reservoir tank described in the above (1) and (2), it is preferable that (3) the supply port is located in the vicinity of the center in the vehicle front-rear direction of the storage chamber in the lower tank portion.

  With this configuration, even if the liquid level in the lower tank portion is inclined in any direction, the supply port can be positioned in the liquid, and air is prevented from being mixed into the working fluid exiting from the supply port.

  Here, the center is a center in an arbitrary direction on the inner bottom surface side of the storage chamber, for example, a position corresponding to the centroid in the horizontal section, and the opening center of the supply port is positioned in the vicinity thereof. For example, the opening diameter of the supply port may be such that the opening extends below the center of gravity of the working fluid at the minimum liquid amount.

  In the reservoir tank described in the above (1) to (3), (4) the inlet is located on the vehicle rear side of the storage chamber in the upper tank portion from the center in the vehicle front-rear direction. Good.

  With this configuration, the liquid level is unlikely to reach the inlet during sudden braking when the liquid level inclination is large, and the maximum liquid amount is difficult to be restricted, so that a reservoir tank with high volumetric efficiency is obtained.

  In the reservoir tank described in the above (1) to (4), (5) it is desirable that the supply port is opened in the vicinity of the lowest inner wall surface in the vertical direction of the lower tank portion.

  With this configuration, the state in which the supply port is located in the liquid is maintained, and the ineffective volume is sufficiently reduced in combination with the effect of reducing the volume of the lower tank portion.

  In the reservoir tank described in the above (1) to (5), (6) it is preferable that the inlet is opened in the vicinity of the uppermost inner wall surface in the vertical direction of the upper tank portion.

  With this configuration, the liquid level is unlikely to reach the injection port, and the maximum liquid amount is difficult to be restricted, so that the reservoir tank has a high volumetric efficiency.

  In the reservoir tank described in the above (1) to (6), (7) the inlet is opened in the vicinity of a position corresponding to the inner wall surface of the lower tank portion on the vehicle rear side in the vehicle longitudinal direction. Is preferred.

  With this configuration, the horizontal cross-sectional area of the storage chamber increases rapidly in the vicinity of the upper end of the inner wall surface on the vehicle rear side of the lower tank portion, and the liquid level is difficult to reach by the inlet when the liquid level is inclined. It becomes a reservoir tank.

  The reservoir tank described in the above (1) to (6) is (8) inclined so that the inner wall surface on the vehicle rear side of the lower tank portion is positioned on the vehicle rear side on the upper side, and the injection port You may open in the vicinity of the position corresponding to the upper end part of the said inner wall surface in a direction.

  With this configuration, the movement of the working fluid in the vicinity of the supply port can be suppressed, and the scattering of the working fluid when the liquid level is inclined due to the acceleration of the vehicle can be suppressed. A good reservoir tank.

  According to the present invention, the volume of the lower tank part is suppressed, and the minimum liquid amount required to position the supply port in the liquid when the liquid level is inclined due to sudden braking or the like is sufficiently reduced, while the upper tank part The required tank capacity is secured sufficiently, and the center of the upper tank in the longitudinal direction of the vehicle is positioned on the rear side of the vehicle in the lower tank. It is possible to provide a highly efficient reservoir tank capable of ensuring the effect of reducing the ineffective volume by suppressing the amount of movement of the liquid surface at the time of sudden braking in which the liquid surface inclination becomes large while ensuring sufficiently.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view of a reservoir tank according to an embodiment of the present invention, in which a hydraulic circuit connected to the reservoir tank is shown by a block. 2A is a schematic top view of the reservoir tank, FIG. 2B is a schematic side view of the reservoir tank, and FIG. 3 is a schematic front view of the reservoir tank.

  First, the configuration will be described.

  As shown in FIG. 1, the reservoir tank 10 of the present embodiment can stably supply hydraulic oil (liquid working fluid) supplied to the fluid pressure circuit 1 in the fluid pressure circuit 1 mounted on the vehicle. It is to be stored and is constituted by a lower tank portion 11 and an upper tank portion 12 that are integrally coupled to each other. In addition, the reservoir tank 10 is configured such that the concave tank members 10a and 10b facing each other are integrally coupled at the periphery of the opening, thereby defining a storage chamber 13 having a constant volume inside. Although not described in detail, the fluid pressure circuit 1 is configured by a hydraulic control circuit of a known power steering device that generates an auxiliary steering force by, for example, hydraulic pressure (hydraulic pressure).

  As schematically shown in FIGS. 2 and 3, the lower tank portion 11 of the reservoir tank 10 has a small volume within the range of the height H1 (see FIG. 2B) in the storage chamber 13 for storing hydraulic oil. A vertical lower side portion 13a that is a chamber is defined. A circular supply port 11a for supplying hydraulic oil to the fluid pressure circuit 1 is disposed on the inner bottom surface portion 11b side of the lower tank portion 11, and the supply port 11a is in the vertical direction of the storage chamber 13 in the vehicle front-rear direction. It is located in the vicinity of a position corresponding to the center G1 (see FIG. 1; details will be described later) of the lower side portion 13a, and is opened in the vicinity of the inner bottom surface portion 11b at the bottom in the vertical direction of the lower tank portion 11.

  The supply port 11a is formed by, for example, a tubular member 11p that is vertically mounted on the inner bottom surface portion 11b of the lower tank portion 11 of the reservoir tank 10, and as shown in FIG. It opens to the position of height h1 from the inner bottom wall surface.

  In FIG. 1, the lower tank portion 11 of the reservoir tank 10 is formed with a return port 11 i through which hydraulic oil from the fluid pressure circuit 1 flows. The return port 11 i is formed in the lower tank portion 11. It may be formed not on the bottom surface portion 11 b side but on the side wall surface portion or the upper tank portion 12 around it. In this embodiment, considering the occurrence of backflow of hydraulic oil, the return port 11i is always located in the liquid as shown in FIG. 1 as in the supply port 11a, and both are opened at the same height. Yes. However, in FIG. 2, the supply port 11a and the return port 11i are shown together as one virtual opening having an opening diameter d1.

  The upper tank portion 12 of the reservoir tank 10 is formed by cutting the vertical upper portion 13b that is a chamber within the range of the height H2 (see FIG. 2B) of the storage chamber 13 from the horizontal lower portion 13a. The area is defined to be larger, that is, to be larger than the vertically lower portion 13a per unit height.

  A circular inlet 12a is formed in the ceiling portion 12b of the upper tank portion 12 so that hydraulic oil can be injected into the storage chamber 13 from the outside. The inlet 12a is open in the vicinity of the ceiling portion 12b (uppermost inner wall surface portion in the vertical direction) of the upper tank portion 12, and in the vehicle front-rear direction, in the vicinity of the inner wall surface 11c on the vehicle rear side of the lower tank portion 11. It is open at the position.

  The inlet 12a is formed by, for example, a tubular member 12p that is vertically mounted on the ceiling portion 12b of the upper tank portion 12 of the reservoir tank 10, and has an opening diameter at a height h2 from the ceiling wall surface of the upper tank portion 12. Open with d2. The inlet 12a of the upper tank portion 12 allows air to enter and exit the storage chamber 13 as the pressure in the storage chamber 13 changes, while preventing leakage of hydraulic oil in the storage chamber 13. A known cap 15 having a breather function is detachably attached.

  As schematically shown in FIGS. 2 and 3, the storage chamber 13 has a substantially square shape in which four corners are rounded in the lower portion 13a in the vertical direction (the length L1 in the front-rear direction in FIG. The length L2) has a horizontal cross-sectional shape, and in the vertical upper portion 13b, four corners are rounded and are substantially rectangular in the longitudinal direction of the vehicle (front-rear length L3> left-right length in FIG. 2A). L4) horizontal cross-sectional shape.

  Heights H1 and H2, front and rear lengths L1 and L3, and left and right lengths L2 and L4 that specify the shapes of the vertical lower portion 13a and the vertical upper portion 13b of the storage chamber 13 reduce the ineffective volume, and The effective volume is set to be large, and at least the longitudinal length L3> the longitudinal length L1 or L4> L2.

  Here, the invalid volume and the effective volume will be described with reference to FIG.

  4A is an explanatory diagram of the relationship between the invalid volume of the reservoir tank and the tank shape on the supply port side, and FIG. 4B is an explanatory diagram of the relationship between the effective volume of the reservoir tank and the tank shape on the inlet side. is there. For convenience of explanation, in FIG. 4, the supply port 11a and the injection port 12a are positioned at the center as viewed in the vehicle front-rear direction.

  In FIG. 4A, for example, the supply port 11a is stored under a state where the liquid level is inclined by 45 degrees due to an acceleration of 1 G (equivalent to gravitational acceleration) acting on the hydraulic oil in the storage chamber 13 in the direction of arrow A. The minimum amount of hydraulic fluid required to be always positioned in the liquid in the chamber 13 is stored. This minimum liquid amount corresponds to the invalid volume. In FIG. 4B, similarly, the inlet 12a is placed in the liquid in the storage chamber 13 under a state where the liquid level is inclined by 45 degrees due to the acceleration of 1 G acting on the hydraulic oil in the storage chamber 13. The maximum amount of hydraulic fluid required to keep it from contacting is stored. The liquid volume corresponding to the liquid level change between the liquid level Ls2 at this time and the liquid level Ls1 at the minimum liquid level shown in FIG. 4A corresponds to the effective volume.

When the reservoir tank 10 has a rectangular horizontal cross section and the effective volume Ve is considered when the width in the direction perpendicular to the cross section is L on the cross section as shown in FIGS. 4 (a) and 4 (b), it is effective. The volume Ve is Ve = {W × H− (1/2) · (W / 2 + r ₁ + h ₁ ) ² − (1/2) · (W / 2 + r ₂ + h ₂ ) ² } × L = L [W { H-W / 4- (1/2) · (h ₁ + h ₂ + r ₁ + r ₂ )}-(1/2) · (h ₁ ² + h ₂ ² + r ₁ ² + r ₂ ² + 2h ₁ r ₁ + 2h ₂ r ₂ )].

  In FIG. 2, the longitudinal length L3, which is the depth dimension in the vehicle longitudinal direction of the storage chamber 13 (vertical upper side portion 13b) in the upper tank portion 12, is the storage chamber 13 (vertical in the vertical direction). The lower side portion 13a) is longer than the longitudinal length L1 which is the depth dimension in the vehicle longitudinal direction, and the left and right length L4 which is the inner width dimension of the upper tank portion 12 in the lateral direction of the vehicle is It is larger than the left and right length L2, which is the inner width dimension in the vehicle left-right direction. Further, in the schematic shape illustrated in FIG. 2, the front-rear length L3 of the vertical upper portion 13b is about twice the front-rear length L1 of the vertical lower portion 13a. The left / right length L4 is about 1.7 times the left / right length L2 of the lower portion 13a in the vertical direction.

  On the other hand, in the reservoir tank 10, as shown in FIG. 1, the center G2 of the storage chamber 13 (vertical upper portion 13b) in the upper tank portion 12 is the storage chamber in the lower tank portion 11 in the vehicle front-rear direction. 13 (vertical lower portion 13a) is offset from the center G1 so as to be located on the vehicle rear side. In the present embodiment, the center G2 of the storage chamber 13 in the upper tank portion 12 is substantially at the same position in the vehicle left-right direction with respect to the center G1 of the storage chamber 13 in the lower tank portion 11.

  The center G1, G2 in the vehicle front-rear direction of the storage chamber 13 in the lower tank portion 11 and the upper tank portion 12 referred to here is the vertical lower side portion 13a and the vertical upper side portion 13b of the storage chamber 13, respectively. Hydraulic oil is injected at a position corresponding to the centroid in the horizontal section, and between the lower limit position PL (minimum fluid level value) and the upper limit position PU (maximum fluid level) where the fluid level is set. This corresponds to the position of the center of gravity of the hydraulic oil stored in the lower portion 13a in the vertical direction and the position of the center of gravity of the hydraulic oil stored in the upper portion 13b in the vertical direction. Further, the offset amount is set within a range in which the position of the center of gravity of the hydraulic oil stored in the upper portion 13b in the vertical direction is always located within the horizontal section of the lower portion 13a in the vertical direction.

  Furthermore, the supply port 11a may extend so as to cover the horizontal movement range of the gravity center position of the hydraulic oil stored in the vertical lower portion 13a. That is, the opening diameter of the supply port 11a may be, for example, such that the opening extends below the center of gravity of the hydraulic fluid at the minimum liquid amount. The opening center of the supply port 11a is located above the center of gravity of the hydraulic oil stored in the lower portion 13a in the vertical direction (the center of the center of gravity movement range).

  As shown in FIGS. 1 and 2, when the upper tank portion 12 and the lower tank portion 11 have horizontal sections that are symmetrical in the front-rear direction, the amount of offset in the vehicle front-rear direction between the tank portions 11, 12 is, for example, This corresponds to the difference in the amount of bulging of the upper part 13b in the vertical direction of the storage chamber 13 bulging forward and backward with respect to the lower part 13a in the vertical direction.

  The inlet 12 a provided in the upper tank portion 12 of the reservoir tank 10 is located on the vehicle rear side from the center G <b> 2 of the storage chamber 13 in the upper tank portion 12.

  Further, the inner wall surface 11c on the vehicle rear side of the lower tank portion 11 is a wall surface inclined toward the vehicle rear side so as to be positioned on the vehicle rear side on the upper side, and the inlet 12a is formed on the inner wall surface 11c in the vehicle front-rear direction. It is opened in the vicinity of the upper end portion 11d.

  Next, the operation will be described.

In the reservoir tank 10 of the present embodiment configured as described above, for example, when the vehicle is suddenly braked, the hydraulic fluid level in the storage chamber 13 is greatly inclined backward as indicated by Lsb in FIG. During acceleration, the liquid level of the hydraulic oil in the storage chamber 13 is inclined forward as indicated by Lsa in FIG. Further, when the vehicle turns, the liquid level is inclined in the direction opposite to the direction of the centrifugal force (lateral G) depending on the direction of the vehicle. Furthermore, the liquid level of the working oil in the storage chamber 13 is also inclined by the inclination of the road surface on which the vehicle travels. Alternatively, when the amount of hydraulic fluid consumed in the fluid pressure circuit 1 including the hydraulic differential device changes, the fluid level of the hydraulic fluid in the storage chamber 13 fluctuates, and the fluid volume decreases due to liquid leakage or the like. There is also.
Thus, although the liquid level of the hydraulic oil in the storage chamber 13 changes, in the reservoir tank 10 of the present embodiment, the volume of the lower tank portion 11 is suppressed, and the supply port is at the time of a large liquid level inclination due to sudden braking or the like. The ineffective volume corresponding to the minimum liquid amount required for positioning 11a in the liquid is sufficiently reduced. Further, a sufficient volume of the upper tank portion 12 is secured, and a required tank capacity is efficiently secured. Further, since the vehicle longitudinal direction center G2 of the storage chamber 13 in the upper tank portion 12 is located on the vehicle rear side of the vehicle longitudinal direction center G1 of the storage chamber 13 in the lower tank portion 11, the liquid level inclination It is possible to suppress the amount of movement of the liquid level at the time of sudden braking, in which the amount of increase is large, and to secure the effect of reducing the ineffective volume.

  In the present embodiment, the depth dimension and the width dimension of the storage chamber 13 in the upper tank portion 12 in the vehicle front-rear direction are larger than the depth dimension and the width dimension of the storage chamber 13 in the lower tank portion 11 in the vehicle front-rear direction, respectively. Therefore, it is possible to suppress the total height of the reservoir tank 10 and sufficiently suppress the ineffective volume while ensuring a sufficient volume of the upper tank portion 12.

  Further, the supply port 11a is located in the vicinity of the center G1 of the storage chamber 13 in the front-rear direction of the storage chamber 13 in the lower tank portion 11, and is opened in the vicinity of the inner bottom surface portion 11b in the lowest vertical direction of the lower tank portion 11. Therefore, even if the liquid level in the lower tank portion 11 is inclined in any direction, the state in which the supply port 11a (opening) is located in the liquid is maintained, and air is mixed into the hydraulic oil exiting from the supply port 11a. In addition, the ineffective volume is sufficiently reduced in combination with the effect of reducing the volume of the lower tank portion 11.

  Moreover, since the inlet 12a is located in the vehicle rear side from the center in the vehicle front-rear direction of the storage chamber 13 in the upper tank portion 12 in the vicinity of the uppermost ceiling portion 12b in the vertical direction of the upper tank portion 12, the liquid level The liquid level does not easily reach the injection port 12a at the time of sudden braking in which the inclination increases, and the maximum liquid amount is difficult to be limited. Therefore, the reservoir tank has a good volumetric efficiency.

  In particular, in the present embodiment, the inlet 12a opens in the vicinity of the inner wall surface 11c on the vehicle rear side of the lower tank portion 11 in the vehicle front-rear direction, so that it is near the upper end of the inner wall surface 11c inclined toward the vehicle rear side. Thus, the horizontal cross-sectional area of the storage chamber 13 increases rapidly, so that the liquid level is difficult to reach through the injection port 12a, and a reservoir tank with good volumetric efficiency is obtained.

  As described above, in the reservoir tank of the present embodiment, the volume of the lower tank portion 11 is suppressed, and the minimum liquid amount required to position the supply port 11a in the liquid when the liquid level is inclined due to sudden braking or the like is obtained. While the corresponding ineffective volume is sufficiently reduced, the volume of the upper tank portion 12 is sufficiently secured to secure the required tank capacity, and the vehicle center in the vehicle longitudinal direction of the upper tank portion 12 is set to the vehicle of the lower tank portion 11. Since it is positioned on the vehicle rear side with respect to the front-rear direction center G1, the volume of the upper tank portion 12 is sufficiently secured, but the amount of liquid level movement during sudden braking with a large liquid level inclination is suppressed, and the ineffective volume is reduced. It is possible to provide a volumetric efficient reservoir tank capable of ensuring a reduction effect.

Incidentally, FIG. 5 shows a comparison of effective volume differences between the reservoir tank 10 of the present embodiment and the conventional reservoir tank. The horizontal axis in the figure (a) is the tank height [mm], the vertical axis in the figure (a) is the effective volume [mL (milliliter)], and the horizontal axis in the figure (b) is the tank bottom area [ mm ³ ], and the vertical axis in FIG. 4B is the effective volume [mL (milliliter)].

  When compared at the same tank height as shown in FIG. 5A or when compared at the same bottom area as shown in FIG. 5B, the upper tank portion and the lower tank portion as in this embodiment. It is clear that the effective volume can be ensured by reducing the invalidation request by making the volumes different, and it can be seen that an efficient reservoir tank can be obtained when the installation space is limited.

  In the above-described embodiment, the horizontal cross section (planar cross section) of the reservoir tank 10 is substantially rectangular. However, other horizontal cross sectional shapes such as an elliptical shape, a substantially semicircular shape, and other cross sectional shapes may be used. . Further, although the centers G1 and G2 of the lower tank portion and the upper tank portion are assumed to be at substantially the same position in the vehicle left-right direction, they may be offset in the left-right direction. Furthermore, even if the inner width of the upper tank portion is narrower than the lower tank portion (the length in the left-right direction of the vehicle is smaller), and the rear end side of the upper tank portion is wider than the lower tank portion. Good. Needless to say, the reservoir tank is not limited to the one provided in the hydraulic pressure control circuit of the hydraulic power steering apparatus.

  As described above, the reservoir tank according to the present invention suppresses the volume of the lower tank portion, and has a sufficient minimum liquid amount required to position the supply port in the liquid when the liquid level is inclined due to sudden braking or the like. While ensuring sufficient volume of the upper tank part to secure the required tank capacity, and the vehicle front-rear direction center of the upper tank part is located on the vehicle rear side from that in the lower tank part. Provides a volume-efficient reservoir tank that can secure the effect of reducing the ineffective volume by suppressing the amount of liquid level movement during sudden braking where the liquid level gradient increases while ensuring sufficient volume of the upper tank part A reservoir tank, in particular, a reservoir for storing a liquid working fluid supplied to the fluid pressure circuit in a fluid pressure circuit mounted on a vehicle so as to be able to be supplied It is useful to Batanku General.

It is a side view of the reservoir tank concerning one embodiment of the present invention, and shows the hydraulic circuit connected to the reservoir tank with the block. (A) is a schematic top view of the reservoir tank which concerns on one Embodiment, (b) is a schematic side view of the reservoir tank which concerns on one Embodiment. It is a schematic front view of the reservoir tank concerning one embodiment. (A) is explanatory drawing of the relationship between the invalid volume of the reservoir tank which concerns on one Embodiment, and the tank shape of the supply port side, (b) is the effective volume of the reservoir tank which concerns on one Embodiment, and the inlet side. It is explanatory drawing of the relationship of a tank shape. It is explanatory drawing which shows the expansion effect of the effective volume of the reservoir tank which concerns on one Embodiment of this invention compared with a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluid pressure circuit 10 Reservoir tank 10a, 10b Tank member 11 Lower tank part 11a Supply port 11b Inner bottom face part (lowermost inner wall face part)
11c inner wall surface 11d upper end portion 12 upper tank portion 12a inlet 12b ceiling portion (uppermost inner wall surface portion)
13 Storage chamber 13a Vertical lower portion 13b Vertical upper portion 15 Cap d1, d2 Opening diameter G1, G2 Center h1 Supply port opening height H1, H2 Tank height L1, L3 Longitudinal length (depth dimension)
L2, L4 Horizontal length (inner width of tank part)
r1, r2 opening radius

Claims (8)

A reservoir tank for storing a liquid working fluid supplied to the fluid pressure circuit in a fluid pressure circuit mounted on a vehicle,
A lower tank portion defining a vertical lower side portion of the storage chamber for storing the working fluid and having a supply port for supplying the working fluid to the fluid pressure circuit;
An upper tank portion in which a vertical upper portion of the storage chamber is defined so that a horizontal cross-sectional area is larger than that of the lower portion in the vertical direction, and an inlet for injecting the working fluid into the storage chamber is formed. And comprising
The reservoir tank characterized in that the center of the storage chamber in the upper tank portion in the vehicle longitudinal direction is located on the vehicle rear side of the storage chamber in the lower tank portion in the vehicle longitudinal direction.   2. The reservoir tank according to claim 1, wherein a depth dimension of the storage chamber in the longitudinal direction of the vehicle in the upper tank portion is larger than a depth dimension of the reservoir chamber in the longitudinal direction of the vehicle in the lower tank portion.   3. The reservoir tank according to claim 1, wherein the supply port is located in the vicinity of the center of the storage chamber in the vehicle front-rear direction in the lower tank portion.   The claim according to any one of claims 1 to 3, wherein the inlet is located on the vehicle rear side of the center of the storage chamber in the upper tank portion in the vehicle front-rear direction. Reservoir tank as described.   The reservoir tank according to any one of claims 1 to 4, wherein the supply port is opened in the vicinity of an inner wall surface portion at a lowest position in the vertical direction of the lower tank portion.   6. The reservoir tank according to claim 1, wherein the inlet is opened in the vicinity of the uppermost inner wall surface in the vertical direction of the upper tank portion. 7.   The said injection port is opened in the vicinity of the position corresponding to the inner wall surface of the vehicle rear side of the said lower tank part in the vehicle front-back direction, The one of Claim 1 thru | or 6 characterized by the above-mentioned. The reservoir tank according to Item.   The lower tank portion is inclined so that the inner wall surface on the rear side of the vehicle is located on the upper side and on the rear side of the vehicle, and the inlet is opened near the position corresponding to the upper end of the inner wall surface in the vehicle front-rear direction. The reservoir tank according to any one of claims 1 to 6, wherein the reservoir tank is provided.

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