Fluid handling – With means for separating solid material from the fluid – Planar strainer normal to flow path
Reexamination Certificate
2000-11-13
2002-05-07
Rivell, John (Department: 3753)
Fluid handling
With means for separating solid material from the fluid
Planar strainer normal to flow path
C137S576000, C060S454000
Reexamination Certificate
active
06382245
ABSTRACT:
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Application No. HEI 11-321085 filed on Nov. 11, 1999 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a resinous reservoir tank that is employed in a system such as a hydraulic power steering system and designed to store and filter working fluid.
2. Description of the Related Art
U.S. Pat. No. 2,944,487 discloses a resinous reservoir tank according to the related art. This reservoir tank is designed to store and filter working fluid in a hydraulic power steering system.
More specifically, the reservoir tank is composed of a cylindrical resinous upper tank (cover), a bottom-closed cylindrical resinous lower tank (reservoir) and a strainer. An inflow pipe (return pipe) and a current plate are integrated with the upper tank. An outflow pipe (bush) and a bracket are secured to the lower tank by means of insert molding. The strainer is mounted to a step portion of the lower tank. The upper tank and the lower tank are connected to each other by means of vibration welding.
Using the bracket, the reservoir tank is securely laid on an oil pump of the hydraulic power steering system. The working fluid that has flown into the upper tank from the inflow pipe is filtered by the strainer and then flows out towards the oil pump.
In such a resinous reservoir tank according to the related art, the lower tank is fixed in position by the bracket. The upper tank having the inflow pipe may be connected to the lower tank with the inflow pipe oriented in a desired direction. Therefore it becomes possible to freely set the direction of the inflow pipe in accordance with the condition of a relevant motor vehicle.
In the resinous reservoir tank according to the related art as described above, the inflow pipe disposed in the upper tank can freely be oriented with respect to the lower tank that is fixed in position by the bracket.
As is the case with this related art, if the reservoir tank is laid on the oil pump, the outflow pipe may be hung from the lower tank and directly connected to the intake side of the oil pump.
However, if the reservoir tank and the oil pump are separately installed, they are connected to each other by a pipe line. The outflow pipe is required to be oriented, for example, in accordance with the positional relation between the reservoir tank and the oil pump.
In such a case, it is considered to use an elbow-type outflow pipe, orient it in a predetermined direction and integrate it with the lower tank by means of insert molding. However, this requires a die corresponding to the direction of the outflow pipe and therefore increases the cost.
Alternatively, it is possible to prepare an elbow-type outflow pipe as a resinous compact separate from the lower tank and connect the outflow pipe to the lower tank by means of welding. However, the outflow pipe and the lower tank can be welded to each other merely over a length equal to the outer circumference of the outflow pipe. Therefore it is impossible to sufficiently guarantee bonding strength and sealability between both the components.
If working fluid is at a low temperature for example during the winter season, it demonstrates high viscosity and is therefore unlikely to penetrate the strainer. If the oil pump is operated in this state, the oil pump connected to the outflow pipe cannot suck a sufficient amount of working fluid. As a result, harmful noise may be generated in the oil pump.
SUMMARY OF THE INVENTION
The invention has been made to solve the aforementioned problems. According to a first aspect of the invention, there is provided a resinous reservoir tank comprising a resinous upper tank having an inflow pipe and a resinous lower tank having an outflow pipe, wherein a generally ring-shaped resinous intermediate member having a bracket-mounting portion is interposed between the upper tank and the lower tank, wherein the upper tank and the intermediate member are connected to and integrated with each other, and wherein the intermediate member and the lower tank are connected to and integrated with each other.
In this construction, the upper tank having the inflow pipe and the lower tank having the outflow pipe are separated from the intermediate member to which the bracket is attached. Therefore, when connecting the upper tank to the intermediate member and the intermediate member to the lower tank, if their relative angles in the rotational direction are set appropriately, it becomes possible to orient the inflow pipe and the outflow pipe in desired directions with respect to the intermediate member that is fixed in position by the bracket. Consequently, a widely applicable reservoir tank can be provided at a low cost.
In the aforementioned aspect of the invention, the upper tank and the intermediate member may be connected to each other by means of welding, and the intermediate member and the lower tank may be connected to each other by means of welding.
In this construction, the upper tank, the intermediate member and the lower tank are secured to one another by means of welding. Therefore, in addition to the aforementioned effect, the upper tank and the lower tank can easily be set to desired angles with respect to the intermediate member.
In the aforementioned aspect of the invention, the intermediate member may be composed of a generally ring-shaped ring portion and a bracket-mounting portion disposed in part of the ring portion, and a strainer may be disposed along the inner circumference of the ring portion.
In this construction, since the strainer is disposed along the inner circumference of the generally ring-shaped intermediate member, it becomes possible to employ, for example, a method of forming the strainer by means of insert molding. Therefore, in addition to the aforementioned effects, the strainer can be installed in the reservoir tank without resorting to an additional process of mounting the strainer.
In the aforementioned aspect of the invention, the lower tank may generally be formed into the shape of a funnel and a largest-diameter section of the generally funnel-shaped lower tank may be made approximately equal in diameter to the strainer, so that the lower tank and the strainer define a funnel chamber, and the outflow pipe may be connected to a smallest-diameter section of the generally funnel-shaped lower tank by means of integral molding.
In this construction, the funnel chamber is defined by the lower tank and the strainer. Thus, if the outflow pipe is connected to the intake side of the oil pump, the negative pressure resulting from a suction force of the oil pump functions over the entire region of the strainer and under the strainer. Therefore, in addition to the aforementioned effects, even working fluid that demonstrates high viscosity because of a low temperature (e.g. power steering oil) can penetrate the strainer easily. Moreover, since a sufficient amount of working fluid is sucked into the oil pump, generation of harmful noise is prevented.
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Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Rivell John
Toyoda Koki Kabushiki Kaisha
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