Rotary expansible chamber devices – With mechanical sealing – Axially movable end wall or end wall portion
Reexamination Certificate
2001-10-29
2003-07-29
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
With mechanical sealing
Axially movable end wall or end wall portion
C418S133000, C418S135000
Reexamination Certificate
active
06599111
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a vane pump, and in particular a vane pump that is suitable as an oil pressure source for a power steering device of an automotive vehicle.
2. Description of the Related Art
As is generally known, there have been proposed vane pumps for a power-steering system of an automotive vehicle. The vane pump typically includes a rotor placed in a cam ring that is received in a pump housing. Plural vanes are slidably provided in corresponding slots formed in the rotor, and a pair of wall members are provided to close both side surfaces of the cam ring. By this arrangement, a pump operation is performed with a rotation of the rotor as a top portion of each vane, and both side surfaces of each vane touch an inner surface of the cam ring, and surfaces of the wall members facing the vane, respectively. This type of apparatus is disclosed in, for example, Japan Utility Model Publication (koukai) No. 6-14481, and Japan Patent Publication (koukai) No. 10-184563.
As shown in
FIG. 18
illustrating one conventional design, oil is supplied from an oil intake passage
101
to an intake port. An intake chamber
102
provided with a concave-shaped groove in its cross section is formed on a rear housing
104
that faces a cam ring
103
in an axial direction of the cam ring
103
. The intake chamber
102
is arranged at an outer portion of the cam ring
103
in a radial direction of the cam ring
103
to avoid an interference with the cam ring
103
. Thus, a size of the vane pump in the radial direction of the cam ring
103
is expanded, when the intake chamber
102
that has a large cross sectional area is formed for the purpose of increasing an induction efficiency. However, since it is undesirable that the size of the vane pump becomes large in view of downsizing, there is a difficulty in providing a compact vane pump that has an intake chamber
102
with a large cross section area. Therefore, it has been difficult to increase the induction efficiency. While the area of the intake chamber
102
can be enlarged by expanding the intake chamber
102
in the axial direction of the cam ring
103
, since the intake chamber
102
is provided with a flat shape cross section, a strong flow resistance results that would cause a decrease of the induction efficiency.
As shown in
FIG. 19
illustrating another conventional design, a fluid chamber
202
is formed inside of a housing member
201
, and receives a pressure plate
203
, a cam ring
204
, and a thrust plate
205
. The pressure plate
203
and the thrust plate
205
are arranged for closing both sides of the cam ring
204
. The fluid chamber
202
is formed into a cylindrical shape. A low-pressure fluid passage
206
, which constitutes an intake passage, is formed on an inner surface of the fluid chamber
202
that faces an outer surface of the cam ring
204
. The low-pressure fluid passage
206
is provided with a concave-shaped groove in its cross section. However, since the low-pressure fluid passage
206
is located at an outside of the cam ring
204
with respect to a diameter of the cam ring
204
, it is difficult to provide the low-pressure fluid passage
206
that has a large cross sectional area, keeping the compactness. Therefore, the area of the low-pressure fluid passage
206
cannot be enlarged enough.
SUMMARY OF THE INVENTION
Accordingly, in view of above-described problems encountered in the related art, a principal object of the present invention is to provide a vane pump that has an intake passage with a large cross sectional area.
Another object of the present invention is to provide a vane pump that is compact.
Still another object of the present invention is to provide a vane pump that is easy to assemble.
In order to achieve these and other objects, there is provided a vane pump that comprises a pump housing that includes an inlet, an outlet, and therein a hollow space, a cam ring received in the hollow space, and a rotor placed in the cam ring. The rotor defines a rotation axis and comprises plural vanes arranged in corresponding slots formed in the rotor with a slidable contact in a radial direction of the rotor. A first wall member is received in the hollow space, with one side of the first wall member facing one side of the cam ring, the first wall member comprising an intake passage provided with a groove that is formed so that a partition wall portion is defined between the intake passage and an interface between the first wall member and the cam ring. A pair of intake ports are formed on the one side of the wall member, and each intake port is connected with the inlet by the intake passage. A pair of outlet ports are formed on the one side of the first wall member.
REFERENCES:
patent: 2653550 (1953-09-01), Gardiner et al.
patent: 3216363 (1965-11-01), Snow et al.
patent: 3647328 (1972-03-01), Fox
patent: 4072450 (1978-02-01), Carlson
patent: 4080124 (1978-03-01), Drutchas et al.
patent: 4199304 (1980-04-01), Strikis et al.
patent: 6050796 (2000-04-01), Wong et al.
patent: 6082983 (2000-07-01), Hayashi et al.
patent: 57-390 (1982-01-01), None
patent: 59-113287 (1984-06-01), None
patent: 59-180088 (1984-10-01), None
patent: 4-76984 (1992-07-01), None
patent: 6-14481 (1994-02-01), None
patent: 10-184563 (1998-07-01), None
Hamao Miyoko
Ishizaki Kazuyoshi
Ohtaki Mizuo
Uchida Yukio
Unisia Jecs Corporation
Vrablik John J.
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