Rotary expansible chamber devices – With plural working fluid inlet or outlet passages
Reexamination Certificate
2001-09-26
2003-04-08
Denion, Thomas (Department: 3748)
Rotary expansible chamber devices
With plural working fluid inlet or outlet passages
C418S075000, C418S077000, C418S079000, C418S166000, C418S171000
Reexamination Certificate
active
06544013
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is based on and claims under 35 U.S.C. § 119 with respect to Japanese Patent Application Nos. 2000-292359 filed on Sep. 26, 2000, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to an oil pump apparatus, and more particularly, an oil pump apparatus driven by a drive source for supplying a predetermined amount of pressurized hydraulic oil to the hydraulic oil receiving portion by a control valve which can flow back a part of hydraulic oil discharged from the oil pump.
BACKGROUND OF THE INVENTION
In Unexamined Published Japanese Patent Applications (Kokai) No.Hei.10 (1998)-73084, for example, there is disclosed a conventional oil pump apparatus. The conventional oil pump apparatus comprises an oil pump housing including a first suction port, a second suction port and a discharge port in the circumferential direction thereof, and a drive rotor and a driven rotor disposed rotatably eccentrically each other in the oil pump housing and forming a plurality of pump chambers in the circumferential direction of the rotor. When the drive rotor is driven by the drive source, each of the pump chambers is moved and is communicated to the first suction port, the second suction port and the discharge port in order, respectively.
In the above prior pump apparatus, a shape of the end portion of the second suction port adjacent to the first suction port is formed so as to be along the shape of the end portion of the pump chamber which abuts on the second suction port and which is sealed momentarily between the first suction port and the second suction port. Further, a shape of the end portion of the first suction port adjacent to the second suction port is formed so as to be along the shape of the end portion of the pocket which abuts the second suction port and which is sealed momentarily between the first suction port and second suction port. Thus, an efficient passage is obtained just before each of the pump chambers is sealed and just after the sealing condition of each of the pump chambers is opened.
Here, in a case where the construction of the above described prior oil pump apparatus is adapted to an oil pump apparatus
20
which has drive rotor
22
having four outer teeth
22
a
and driven rotor
23
having five inner teeth
23
a
disposed eccentrically in the oil pump housing
21
as shown in FIG.
1
and pump chambers R being able to change their volume are formed between the drive rotor
22
and the driven rotor
23
, as shown by two dotted lines, the shape B
1
of the end portion of the second suction port B adjacent to the first suction port A is formed so as to be along the shape R (s portion with slash) of the end portion of the pump chamber R which abuts on the second suction port and which is sealed momentarily between the first suction port A and the second suction port B. Further, as shown by one dotted line in
FIG. 1
, the shape Ao of the end portion of the first suction port A adjacent to the second suction port is formed so as to be along the shape (curving shape with projection toward inner circumference) R
2
of the end portion of the pump chamber R which is adjacent to the first suction port and which is sealed momentarily.
In the above described construction, while the drive rotor
22
and driven rotor
23
are rotated by crank shaft
10
of the vehicle engine (internal combustion engine) counter-clockwise as shown in
FIG. 1
, when the pump chamber R is rotated to the location shown
FIG. 2
, the end portion of the pump chamber R on the rotational direction side is communicated to the second suction port B and the end portion shown by one dotted line of the pump chamber R on the anti-rotational direction side overlaps with the inner circumference portion of the first suction port A and is communicated to the second suction port A. Accordingly, while the first suction port A is communicated to the discharge port C with the operation of the control valve
30
by which the oil pump apparatus can flow a part of the hydraulic oil discharged from oil pump
20
to the suction side (while a spool
31
disposed in the control valve
30
slides against the biasing force of a spring
33
and closes the connection between a port
31
c
and a port
31
d
), the first suction port A and the second suction port B repeat connection and disconnection. The high pressure hydraulic oil flowed from the discharge port C to the first suction port A through the control valve
30
flows from the first suction port A to the second suction port B through the pump chamber R intermittently. Thus, the amount of the hydraulic oil supplied to the hydraulic oil receiving portion decreases. Further, the pulsation of the hydraulic pressure increases and the noise is generated.
SUMMARY OF THE INVENTION
The present invention provides an oil pump apparatus without the foregoing drawbacks.
In accordance with a first aspect of the present invention, an oil pump apparatus comprises an oil pump housing including a first suction port, a second suction port and a discharge port in the circumferential direction thereof, a drive rotor and a driven rotor disposed rotatably eccentrically in oil pump housing and forming a plurality of pump chambers in the circumferential direction of a rotor, and each of the pump chambers communicating to the first suction port, the second port and the discharge port in order, respectively, when the drive rotor and the driven rotor are rotated, wherein a shape of the end portion on the side of the anti-rotational direction at the second suction port is formed so as to be along a shape of the end portion on the side of the rotational direction at the pump chamber. The pump chamber is sealed momentarily between the first suction port and the second suction port, and a shape of the inner circumferential end portion of the first suction port is formed so as to be along the rotational trace of the end portion on the side of the anti-rotational direction at the pump chamber. The pump chamber is sealed momentarily between the first suction port and the second suction port, wherein a plural first pockets or penetrating holes which can be communicated to the first suction port at outer circumferential portion thereof and which cannot be communicated to each port at the same time are formed on the driven rotor, and a second pocket which can be closed at the inner circumferential portion of the pump housing located at the inner side with respect to the first suction port by the drive rotor which can be communicated respectively to the each pump chamber and the inner circumferential portion of the first pocket or penetrating hole is formed on the pump housing and can communicate each pump chamber with the first suction port through the first pocket or penetrating hole when each pump chamber is communicated to the first suction port.
In accordance with the second aspect of the present invention, an oil pump apparatus comprises an oil pump housing including a suction port, a first discharge port and a second discharge port in the circumferential direction thereof, a drive rotor and a driven rotor disposed rotatably eccentrically in a oil pump housing forming a plurality of pump chambers in the circumferential direction of a rotor. Each of the pump chambers communicates to the suction port, the first discharge port and the second discharge port in order, respectively, when the drive rotor and the driven rotor are rotated, wherein a shape of the end portion on the side of the rotational direction at the first discharge port is formed so as to be along a shape of the end portion on the side of the anti-rotational direction at the pump chamber. The pump chamber is sealed momentarily between the first discharge port and the second discharge port, and a shape of the inner circumferential end portion of the second discharge port is formed along the rotational trace of the end portion in the rotational direction at the pump chamber. A plural first pockets or penetrating
Kato Hiroshi
Ono Hisashi
Aisin Seiki Kabushiki Kaisha
Denion Thomas
Trieu Theresa
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