TWI690660B - Bicycle hydraulic device comprising a tank - Google Patents

Abstract

The present invention refers to a bicycle hydraulic device 10 that comprises a tank 11 having a first surface 21, a lid 13 having a second surface 22 facing the first surface 21 and a diaphragm 12 arranged between the tank 11 and the lid 13, the diaphragm 12 having a third surface 23 facing the first surface 21 and a fourth surface 24 facing the second surface 22. The at least one of the first to fourth surfaces 21, 22, 23, 24 of the bicycle hydraulic device 10 has a convex portion 25 extending towards the other surface which faces the at least one of the first to fourth surfaces 21, 22, 23, 24 to achieve a locally increased surface pressure when the bicycle hydraulic device 10 is in an assembled state.

Description

Bicycle hydraulic device including a storage tank

The invention relates to a bicycle hydraulic device including a storage tank. More specifically, the storage tank includes a cover and a partition.

In the past few years, it has been widely used to integrate hydraulic fluid storage tanks in bicycle hydraulic systems. In a bicycle hydraulic system, the movement of a master piston is transmitted to a driven piston. To maintain a position of an object member (eg, a friction member), the bicycle hydraulic system sometimes includes a storage tank. Generally, these storage tanks have a volume separated by a flexible partition into two separate chambers; a gas-containing chamber, a gas reservoir; and a fluid-containing chamber, a fluid reservoir. The commonly used tank design includes a fluid reservoir with a cover and a partition placed between the fluid reservoir and the cover. Sometimes, the seals between the different components of these tanks are not satisfactory.

Accordingly, the technical object of the present invention is to provide a bicycle hydraulic device that is further improved in design so that the hydraulic fluid can be maintained more stable by improving the seal. Use the bicycle hydraulic device according to technical solution 1 to solve the problem. The preferred embodiments are described in the accompanying technical solutions. The bicycle hydraulic device includes: a storage tank having a first surface; and a cover having a second surface facing the first surface; and a partition plate disposed between the storage tank and the cover. The separator has a third surface facing the first surfaces and a fourth surface facing the second surface, wherein at least one of the first to fourth surfaces has a surface facing the first to fourth surfaces A convex portion extending from the other surface of the at least one. In other words, the bicycle hydraulic device is composed of a stack configuration including a storage tank and a cover and a partition placed between the storage tank and the cover. At least one of the four surfaces has a convex portion extending in the direction of its corresponding surface. Within the scope of the present invention, the term "separator" refers to an elastic material that seals against hydraulic fluid, such as a membrane or the like. The purpose of the diaphragm is to compensate for the temporary volume expansion or contraction of the hydraulic fluid by the elastic deformation of the diaphragm. Within the scope of the present invention, the term "convex" refers to the increase in thickness of the corresponding component at a given location on its peripheral edge. However, the term "convex" is not limited to one of the thickness of the part gradually increasing, but covers a wide range of forms and shapes that protrude into the direction of the corresponding surface. In the case where there are no protrusions, the two corresponding surfaces always have the same distance towards each other; the surfaces actually extend parallel to each other. By providing the convex portion, a compensation for the loss of surface pressure along the length of the peripheral edge of the bicycle hydraulic device in an assembled state is achieved. The latter is based on observations due to the elasticity of the tank and the cover, and the surface pressure acting on two or more contact surfaces decreases as the distance to the fastening point increases. Therefore, at a position away from a fastening point, the local surface pressure may be lower than the critical surface pressure that is forced to maintain the tightness of the hydraulic device. According to the invention, the local surface pressure can therefore be locally increased by forcing bending stress on the component in contact with the component having the convex portion. In other words, if the tightening force is thus increased to a sufficient level, a surface with a convex portion forces a flat surface to bend along the curvature of the convex portion. In view of the above, from all four possible first to fourth surfaces in contact with each other, various combinations of convex and non-convex surfaces are possible within the scope of the present invention. It is also possible that all surfaces have a convex portion. The decisive factor is due to the at least one convex portion, the surface pressure along the surfaces locally increases in an assembled state. Within the scope of the present invention, the term "addition" refers to a reference situation in which surfaces used parallel to each other in an assembled state of a bicycle hydraulic device are used. Preferably, the bicycle hydraulic device further includes: a first fastening member that is structurally designed to fasten the cover to the tank via the partition; and a second fastening member that is structurally designed to pass The partition secures the cover to the sump. With the two fastening members, the bicycle hydraulic device can be quickly and easily assembled, preferably at both ends of the bicycle hydraulic device. Within the scope of the present invention, the term "fastening member" includes all devices implemented to increase the surface pressure at the first to fourth surfaces when the bicycle hydraulic device is in an assembled state. Preferably, the first fastening member has a first shaft, the second fastening member has a second shaft, and the convex portion has a top portion in a state where the cover is fastened to the storage tank Is arranged at a portion corresponding to a central portion of a first virtual line extending between the first axis and the second axis. In other words, the curvature of the convex portion has a maximum value positioned in the middle of the two fastening members or near the middle of the two fastening members. In general, if two parallel surfaces are fastened to each other by two fastening members, the surface pressure is at a minimum in the middle section between the two fastening members. Therefore, if the top of the convex portion is located at a central portion of the first virtual line, the local surface pressure can be effectively increased at this position. Preferably, the bicycle hydraulic device further includes a third fastening member that is structurally designed to fasten the cover to the sump via the partition, wherein the third fastening member has a third shaft and is located at the first A second virtual line extending between an axis and the third axis and a third virtual line extending between the second axis and the third axis are shorter than the first virtual line, respectively. The application of a third fastening member has the following advantages: a more complex profile of the bicycle hydraulic device can be achieved; and further fastening members add an additional clamping force at a given position of the bicycle hydraulic device. In a preferred embodiment, even if parallel surfaces are provided along the second and third virtual lines, the second virtual line and the third virtual line still have a length that allows maintaining a sufficient surface pressure along an equal length thereof. Here, according to the present invention, only the surface along the first virtual line has at least one convex portion. Preferably, the first to third fastening members are bolts and the reservoir has first to third reservoir screw holes that respectively receive one of the first to third fastening members. Using bolts, the assembly of the bicycle hydraulic device can be easily achieved, and the required clamping force can be easily applied to the cover and the bulkhead. Preferably, the cover has first to third cover holes aligned with the first to third reservoir screw holes, respectively, and the partition plate has aligned with the first to third reservoir screw holes, respectively First to third partition holes. By aligning the first to third cover holes and the first to third partition holes aligned with the first to third tank screw holes, the component storage tank, partition, and One of the covers is stacked. In addition, even if one or more screws are unintentionally loosened, the partition and/or the cover does not have the risk of being immediately detached from the storage tank. Preferably, the convex portion is provided on one of the cover and the storage tank. Alternatively, the convex portion is provided on the cover. Providing the convex portion on one of the cover and the storage tank (thus, on one of the structures made of a relatively rigid material) has the following advantages: compared to the case where the convex portion is provided on the elastic partition , The surface pressure increases higher. Providing the convex portion on the cover has a further advantage: the surface quality of the peripheral edge of the cover is not as high as the surface quality of the storage tank. Preferably, the cover is made of resin. The resin is a lightweight material with sufficient rigidity and allows greater flexibility in the design and shape of the cover. Preferably, the separator is made of rubber. Rubber is a material that is sufficiently elastic and chemically stable to hydraulic fluids. It is a cheap, durable, and easily available material. Preferably, the storage tank is made of resin. Resin is a lightweight material that is sufficiently rigid and allows one of design and shape to be more flexible and chemically stable to hydraulic fluids. Preferably, the sump is provided on a base member that is structurally designed to be attached to a bicycle handlebar. By mounting the sump to the handle via a base member, it allows easy integration of the sump and further hydraulic components into the bicycle handle. In addition, if the storage tank is located at a high and easily accessible position, it is easier to carry out the bleeding process of the bicycle hydraulic system. Preferably, the base member has: a proximal end portion that is structurally designed to be attached to the bicycle handle; a distal end portion; and a grip portion, which are disposed on the proximal end portion and the distal end portion between. In addition, the bicycle hydraulic device preferably includes: a cylinder barrel provided on the base member; a piston disposed in the cylinder barrel; and an operation member pivotally attached to the distal portion to To operate the piston, the operating member extends downward in a state where the base member is attached to the bicycle handlebar. The invention is particularly suitable for bicycle hydraulic devices having the described base member and operating member, because one of the openings of the storage tank is generally inclined with respect to the horizontal plane. Preferably, the bicycle hydraulic device further includes a shift unit provided on one of the base member and the operating member. The shift unit is easily installed on the bicycle hydraulic device to maintain the stability of the hydraulic fluid. Preferably, the bicycle hydraulic device further includes an elastic cover designed to at least partially cover the base member. The elastic cover improves rider comfort.

FIGS. 1 to 4 depict cross-sectional views through a side portion of a bicycle hydraulic device 10 according to the present invention, which shows different embodiments of the bicycle hydraulic device 10. In these figures, the bicycle hydraulic device 10 is further depicted in an exploded view. The bicycle hydraulic device 10 is shown to include a storage tank 11, a partition 12, and a cover 13. The partition 12 is positioned between the storage tank 11 and the cover 13. The inside of the storage tank 11 stores hydraulic fluid (not depicted). The partition 12 extends across the entire horizontal cross section of the storage tank 11 and separates the bicycle hydraulic device 10 into two chambers: a lower chamber, which is represented by the storage tank 11 filled with hydraulic fluid; and an upper chamber, which is formed by the cover A gas volume between 13 and the partition 12 is indicated. The two chambers are schematically depicted in dashed lines in FIGS. 1-4, as such techniques are well known in the art. The bicycle hydraulic device 10 includes a plurality of fastening members for mounting the cover 13 and the partition 12 to the storage tank 11. 1 to 4 schematically show a first fastening member 14 having a first shaft 15 and a second fastening member 16 having a second shaft 17. In one assembled state of the bicycle hydraulic device 10, the first fastening member 14 and the second fastening member 16 are received in the storage tank 11 by a specific storage tank screw hole 18 provided as a threaded hole. In one assembled state of the bicycle hydraulic device 10, the first fastening member 14 and the second fastening member 16 pass through one of the partition holes 19 and one cover hole of the partition 12 and the cover 13 provided at each fastening point 20. The sump holes 18, the partition holes 19, and the cover holes 20 stacked on top of each other are aligned with each other in a manner that allows the fastening members to pass through the stack of the components. As shown in FIGS. 1 to 4, the bicycle hydraulic device 10 includes specific surfaces. If the bicycle hydraulic device 10 is in an assembled state, contact between two adjacent components occurs on the specific surfaces. In this aspect, the storage tank 11 has a first surface 21, the cover 13 has a second surface 22 and the partition 12 has a third surface 23 and a fourth surface 24. Here, the first surface 21 is considered to be in contact with the third surface 23 and the second surface 22 is considered to be in contact with the fourth surface 24. In the first embodiment of the present invention shown in FIG. 1, the second surface 22 is shown to include a convex portion 25. The second surface 22 is the surface of the cover 13 that contacts the fourth surface 24 of the bulkhead 12 in one assembled state of the bicycle hydraulic device 10. The curvature of the convex portion 25 reaches a peak in a top 26. The top 26 is positioned between the first shaft 15 of the first fastening member 14 and the second shaft 17 of the second fastening member 16. In other words, in a state where the cover 13 is fastened to the sump 11, the top 26 is disposed at a portion corresponding to a first virtual line V1 (FIG. 5) extending between the first shaft 15 and the second shaft 17. In the first embodiment, the top portion 26 is arranged at a portion corresponding to a central portion CP (refer to FIG. 5) of a first virtual line V1. According to the first embodiment shown in FIG. 1, the first surface 21, the third surface 23 and the fourth surface 24 are substantially flat and extend parallel to each other. In the second embodiment of the present invention shown in FIG. 2, the third surface 23 is shown to include a convex portion 25. The third surface 23 is the surface of the partition plate 12 that is in contact with the first surface 21 of the storage tank 11 in one assembled state of the bicycle hydraulic device 10. The curvature of the convex portion 25 reaches a peak in a top 26. The top 26 is positioned between the first shaft 15 of the first fastening member 14 and the second shaft 17 of the second fastening member 16. Like the first embodiment, in the second embodiment, the top portion 26 is configured to correspond to a portion of a central portion CP of a first virtual line V1. According to the second embodiment shown in FIG. 2, the first surface 21, the second surface 22 and the fourth surface 24 are substantially flat and extend parallel to each other. In the third embodiment of the present invention shown in FIG. 3, the fourth surface 24 is shown to include a convex portion 25. The fourth surface 24 is the surface of the partition 12 that is in contact with the second surface 22 of the cover 13 in one assembled state of the bicycle hydraulic device 10. The curvature of the convex portion 25 reaches a peak in a top 26. The top 26 is positioned between the first shaft 15 of the first fastening member 14 and the second shaft 17 of the second fastening member 16. As in the first embodiment, in the third embodiment, the top 26 is configured to correspond to a portion of a central portion CP of a first virtual line V1. According to the third embodiment shown in FIG. 3, the first surface 21, the second surface 22, and the third surface 23 are substantially flat and extend parallel to each other. In the fourth embodiment of the present invention shown in FIG. 4, it is further shown that the first surface 21 includes a convex portion 25. The first surface 21 is the surface of the sump 11 that is in contact with the third surface 23 of the bulkhead 12 in one assembled state of the bicycle hydraulic device 10. The curvature of the convex portion 25 reaches a peak in a top 26. The top 26 is positioned between the first shaft 15 of the first fastening member 14 and the second shaft 17 of the second fastening member 16. As in the first embodiment, in the fourth embodiment, the top 26 is configured to correspond to a part of a central part CP of a first virtual line V1. According to the fourth embodiment shown in FIG. 4, the third surface 23, the second surface 22, and the fourth surface 24 are substantially flat and extend parallel to each other. The partition 12 is made of an elastic material such as rubber or the like, and if a force is applied to the bicycle hydraulic device 10, it is pressed by both the cover 13 and the storage tank 11 through the first surface 21 and the second surface 22 Separator 12. It is necessary to press the stack composed of the storage tank 11, the partition plate 12 and the cover 13 so as to achieve a stable sealing function between the third surface 23 and the fourth surface 24. To obtain a reliable seal, the surface pressure between the first fastening member 14 and the second fastening member 16 must be sufficiently high, as will be described in more detail below. 5 and 6 illustrate the bicycle hydraulic device 10 in an assembled state, wherein FIG. 5 illustrates the bicycle hydraulic device 10 according to the first embodiment of the present invention and FIG. 6 illustrates the fourth embodiment of the present invention. Bicycle hydraulic device 10. The bicycle hydraulic device 10 is installed by a total of three fastening members 14, 16, and 27. In the embodiment shown in FIGS. 5 and 6, the distance between the first fastening member 14 and the second fastening member 16 is greater than the distance between the first fastening member 14 and the third fastening member 27. Also, the distance between the second fastening member 16 and the third fastening member 27 is shorter than the distance between the first fastening member 14 and the second fastening member 16. In other words, a second virtual line V2 extending between the first axis 15 and the third axis 28 and a third virtual line V3 extending between the second axis 17 and the third axis 28 are respectively shorter than the first virtual line V1. From a force flux point of view, when analyzing along the first fastening member 14 and the second fastening member 16 (and optionally the first fastening member 14 or the second fastening member 16 and the third fastening member 27 Between) the surface pressure of the length, two effects must be considered. First, the surface pressure imposed by the first fastening member 14 and the second fastening member 16 on the stack composed of the storage tank 11, the cover 13 and the partition 12 increases as the distance to each of these fastening members increases The decrease gradually depends on the elasticity of the material of the storage tank 11 and the cover 13. Therefore, according to this first aspect only, the surface pressure is at a minimum in the middle of the length between the first fastening member 14 and the second fastening member 16. Therefore, the surface pressure may be different along the length between the first fastening member 14 and the second fastening member 16, making it impossible to ensure a reliable seal. Secondly, the surface pressure imposed on the lid 13 and the partition 12 via the convex portion 25 of the lid 13 depends on the curvature of the convex portion 25. More specifically, when the infinite rigidity of the storage tank 11 and the cover 13 is assumed, the smaller the gap between the first surface 21 and the fourth surface 24, the higher the surface pressure acting on the partition plate 12. According to this second aspect only, therefore, the surface pressure acting on the separator 12 is at a maximum value when the curvature of the convex portion 25 reaches the maximum value at the top portion 26 thereof. Since the materials of the storage tank 11 and the cover 13 are actually elastic to a certain extent, it is necessary to consider the two above-identified aspects in order to maintain along the entire distance between the first fastening member 14 and the second fastening member 16 Surface pressure above one of the critical surface pressures. The latter is achieved by the bicycle hydraulic device 10 according to the invention. Here, the curvature of the convex portion 25 is designed so as to compensate for the reduction of the surface pressure imposed by the fastening members, especially in the middle of the length between the first fastening member 14 and the second fastening member 16. The convex portion 25 may be provided only at the long distance side of the bicycle hydraulic device 10 between the first fastening member 14 and the second fastening member 16. In the illustrated embodiment, the two other sides of the bicycle hydraulic device 10 are short enough to provide a surface pressure sufficient to maintain a critical surface pressure. Exposing the convex portion 25 of the cover 13 causes the separator 12 stacked under the cover 13 to deform according to the curvature of the convex portion 25 of the cover 13. Shown in the middle, at the top 26 of the convex portion 25, the gap between the sump 11 and the cover 13 is at a minimum. Of course, a convex portion 25 may be additionally provided at one or both of the other two sides of the bicycle hydraulic device 10. Fig. 7 schematically illustrates a bicycle hydraulic device 10 attached to a bicycle. Here, the bicycle hydraulic device 10 is incorporated into a base member 29 of a bicycle brake device having an electric shift unit 38 for electrically operating a transmission. The bicycle hydraulic device is mounted to the handlebar 30 via the base member 29. The base member 29 has a proximal portion 31 and a distal portion 32. A grip portion 33 is provided between the proximal portion 31 and the distal portion 32. In addition, a cylinder 34 is provided on the base member 29 and a piston 35 is disposed in the cylinder 34. The piston 35 can be operated via an operating member 36. The operating member 36 is pivotally attached to one of the brake levers of the distal portion 32 of the base member 29. Here, the operation member 36 is attached to the distal end portion 32 of the base member 29 such that the operation member 36 extends downward in a state where the base member 29 is attached to the bicycle belt. As shown, the base member 29 further includes an elastic cover 37 covering one of the grip portions 33 shown in dotted lines. When riding a bicycle, the rider's hand can rest on the elastic cover 37, which therefore increases the comfort of use. Although the shift unit 38 shown in FIG. 7 is an electric shift unit, the present invention can also be applied to a mechanically operated shift unit that is structurally designed to be operated by the inner cable of a Bowden cable.

10‧‧‧Bicycle hydraulic device/hydraulic device 11‧‧‧Storage tank 12‧‧‧Baffle plate 13‧‧‧Cover 14‧‧‧First fastening member 15‧‧‧First shaft 16‧‧‧Second fastening Member 17‧‧‧Second axis 18‧‧‧Slot screw hole/slot hole 19‧‧‧Baffle hole 20‧‧‧ Cover hole 21‧‧‧First surface 22‧‧‧Second surface 23‧‧‧ Three surfaces 24 ‧ ‧ ‧ fourth surface 25 ‧ ‧ ‧ convex part 26 ‧ ‧ top 27 ‧ ‧ ‧ third fastening member 28 ‧ ‧ ‧ third shaft 29 ‧ ‧ ‧ base member 30 ‧‧‧Proximal part 32‧‧‧Distal part 33‧‧‧ Grip part 34‧‧‧Cylinder 35‧‧‧Piston 36‧‧‧Operating member 37‧‧‧Elastic cover 38‧‧‧Shift Unit CP‧‧‧ Central part V1‧‧‧ First virtual line V2‧‧‧ Second virtual line V3‧‧‧ Third virtual line

An embodiment of the present invention will now be described below with reference to the drawings, in which: FIG. 1 is an exploded side view of a bicycle hydraulic device schematically depicting a bicycle according to a first embodiment; FIG. 2 is the diagram according to a second embodiment Fig. 3 is an exploded side view of a bicycle hydraulic device; Fig. 3 is an exploded side view of the bicycle hydraulic device according to a third embodiment; Fig. 4 is a schematic diagram of the bicycle hydraulic device according to a fourth embodiment An exploded side view of one of the devices; FIG. 5 is a view of the assembled bicycle hydraulic device according to a first embodiment; FIG. 6 is a view of the assembled bicycle hydraulic device according to a fourth embodiment; and FIG. 7 is based on A cross-sectional view of a base member of a bicycle hydraulic device according to the present invention. In the description of each of the following embodiments, the same constituent element is given the same element symbol, and repeated description is omitted. In addition, for ease of description, in appropriate cases, a part of these constituent elements is omitted in each drawing.

10‧‧‧Bicycle hydraulic device

11‧‧‧Storage tank

12‧‧‧Partition

13‧‧‧ Cover

14‧‧‧First fastening member

15‧‧‧ First axis

16‧‧‧Second fastening member

17‧‧‧Second axis

25‧‧‧Convex

26‧‧‧Top

27‧‧‧The third fastening member

28‧‧‧The third axis

CP‧‧‧Central part

V1‧‧‧The first virtual line

V2‧‧‧The second virtual line

V3‧‧‧The third virtual line

Claims (15)

A bicycle hydraulic device (10) comprising: a storage tank (11) having a first surface (21); a cover (13) having a second surface (22) facing the first surface (21) ); a partition (12), which is disposed between the storage tank (11) and the cover (13), the partition (12) has a third surface (23) facing the first surface (21) and A fourth surface (24) facing the second surface (22); a first fastening member (14) which is structurally designed to fasten the cover (13) to the tank via the partition (12) (11), the first fastening member (14) has a first shaft (15); and a second fastening member (16), which is structurally designed to pass the cover (13) through the partition (12) ) Fastened to the reservoir (11), the second fastening member (16) has a second shaft (17); characterized in that at least one of the first to fourth surfaces has a direction facing the first A convex portion (25) extending from the other surface of the at least one of the fourth surfaces, and the convex portion (25) has a top portion (26) in which the cover (13) is fastened to In a state of the tank (11), a portion corresponding to a central portion (CP) of a first virtual line (V1) extending between the first axis (15) and the second axis (17) is disposed Office. The bicycle hydraulic device (10) according to claim 1, further comprising: a third fastening member (27) which is structurally designed to fasten the cover (13) to the storage tank via the partition (12) 11); wherein the third fastening member (27) has a third shaft (28), and A second virtual line (V2) extending between the first axis (15) and the third axis (28) and one extending between the second axis (17) and the third axis (28) The third virtual lines (V3) are shorter than the first virtual lines (V1), respectively. The bicycle hydraulic device (10) according to claim 2, wherein the first to third fastening members are bolts, and the sump (11) has first to third receiving members of the first to third fastening members, respectively The third storage screw hole (18). The bicycle hydraulic device (10) according to claim 3, wherein the cover (13) has first to third cover holes (20) respectively aligned with the first to third tank screw holes (18), and the partition The plate (12) has first to third partition holes (19) aligned with the first to third tank screw holes (18), respectively. The bicycle hydraulic device (10) according to any one of claims 1 to 4, wherein the convex portion (25) is provided on one of the cover (13) and the storage tank (11). The bicycle hydraulic device (10) according to claim 5, wherein the convex portion (25) is provided on the cover (13). The bicycle hydraulic device (10) according to any one of claims 1 to 4, wherein the cover (13) is made of resin. The bicycle hydraulic device (10) according to any one of claims 1 to 4, wherein the partition plate (12) is made of rubber. The bicycle hydraulic device (10) according to any one of claims 1 to 4, wherein the storage tank (11) is made of resin. The bicycle hydraulic device (10) according to any one of claims 1 to 4, wherein the storage tank (11) is provided on a base member (29) which is structurally designed to be attached to a bicycle handlebar (30). The bicycle hydraulic device (10) according to claim 10, wherein the base member (29) has: a proximal portion (31) which is structurally designed to be attached to the bicycle handlebar (30); a distal portion ( 32); and a grip portion (33), which is disposed between the proximal portion (31) and the distal portion (32). The bicycle hydraulic device (10) according to claim 11, further comprising: a cylinder (34), which is disposed on the base member (29); and a piston (35), which is disposed on the cylinder (34) Medium; and an operating member (36) pivotally attached to the distal portion (32) to operate the piston (35), the operating member (36) in which the base member (29) is attached to The bicycle handle (30) extends downward in one state. If the bicycle hydraulic device (10) of claim 12, it further includes: A shift unit (38) is provided on one of the base member (29) and the operating member (36). The bicycle hydraulic device (10) according to claim 10, further comprising: an elastic cover (37) which is structurally designed to at least partially cover the base member (29). A bicycle hydraulic device (10) comprising: a storage tank (11) having a first surface (21); a cover (13) having a second surface (22) facing the first surface (21) ); a partition (12), which is disposed between the storage tank (11) and the cover (13), the partition (12) has a third surface (23) facing the first surface (21) and A fourth surface (24) facing the second surface (22); a first fastening member (14) which is structurally designed to fasten the cover (13) to the tank via the partition (12) (11), the first fastening member (14) has a first shaft (15); and a second fastening member (16), which is structurally designed to pass the cover (13) through the partition (12) ) Fastened to the reservoir (11), the second fastening member (16) has a second shaft (17); characterized in that at least one of the first to fourth surfaces has a direction facing the first A convex portion (25) extending from the other surface of the at least one of the fourth surfaces, the convex portion (25) has a top portion (26), the top portion (26) is disposed on the first axis (15) and the At a portion between the second shaft (17), and the partition plate has an outer peripheral surface exposed from the storage tank (11) and the cover (13).

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