(1) Field of the Invention
The present invention relates to a variable displacement oil pump applicable to a hydraulic pressure source from which oil is supplied to, for example, respective slide sections of an internal combustion engine for use in an automotive vehicle.
(2) Description of Related Art
A Japanese Patent Application first Publication No. 2014-105623 exemplifies a previously proposed variable displacement oil pump applicable to the internal combustion engine of the automotive vehicle.
That is to say, in this variable displacement oil pump, a main gallery pressure of the engine, namely, a hydraulic pressure of drained oil after a passage of an oil filter is fed back to a pair of first and second control oil chambers partitioned between a pump housing and a cam ring so as to be mutually opposed so that an eccentricity of the cam ring is variably controlled according to the main gallery pressure. Thus, an energy loss based on a difference pressure between the drain pressure and the main gallery pressure during a drive of the pump is reduced.
However, in a case of the previously proposed variable displacement oil pump, it is necessary to install a drain passage partitioned for the respective control oil chambers to be not communicated at back sides of the respective control oil chambers when a drained oil is introduced into a main gallery. A large sizing of the pump in an axial direction of the pump by the drain passage and by a partitioning wall partitioning this drain passage is resulted.
With the above-described technical task of the previously proposed variable displacement oil pump in mind, it is an object of the present invention to provide a variable displacement oil pump which can suppress the large sizing in the axial direction of the pump while adopting the structure of feedback controlling by means of the main gallery pressure.
According to one aspect of the present invention, there is provided a variable displacement oil pump, comprising: a pump element rotationally driven by means of an internal combustion engine and which absorbs oil via an absorption section and drains oil via a drain section when an internal volume of a plurality of pump chambers is varied; a variable mechanism which increases or decreases a volume variation quantity of the plurality of pump chambers according to a movement of a movable member; a biasing member installed in a state in which a pre-load is acted and which biases the movable member in a direction in which the volume variation quantity of the plurality of pump chambers is increased; a first control oil chamber which serves to generate a biasing force in a direction in which the volume variation quantity of the plurality of pump chambers is decreased for the movable member according to a hydraulic pressure introduced from the internal combustion engine; a second control oil chamber which serves to generate the biasing force in a direction in which the volume variation quantity of the plurality of pump chambers is increased for the movable member according to the hydraulic pressure introduced from the internal combustion engine; a control mechanism which controls a hydraulic pressure introduced into the first control oil chamber and the second control oil chamber; and a drain chamber partitioned with respect to the first control oil chamber and the second control oil chamber and which serves to generate the biasing force in a direction in which the volume variation quantity of the plurality of pump chambers is varied on a basis of the hydraulic pressure directly introduced from the drain section.
According to another aspect of the present invention, there is provided a variable displacement oil pump, comprising: a rotor rotationally driven by means of an internal combustion engine; a plurality of vanes housed to be projectable from and retractable into an outer periphery of the rotor; a cam ring partitioning a plurality of pump chambers by housing the rotor and the vanes in an inner peripheral side of the cam ring and increasing or decreasing a volume variation quantity of a plurality of pump chambers by eccentrically moving with respect to the rotor; an absorption section which is opened to an absorption region in which an internal volume of the pump chambers is increased; a drain section which is opened to a drain region in which the internal volume of the pump chambers is decreased; a biasing member installed in a state in which a pre-load is acted and which biases the cam ring in a direction in which an eccentricity is increased; a first control oil chamber which serves to generate a biasing force in a direction in which a volume variation quantity of the plurality of pump chambers is decreased for the cam ring according to a hydraulic pressure introduced from the internal combustion engine; a second control oil chamber which serves to generate the biasing force in a direction in which the volume variation quantity of the plurality of pump chambers is increased for the cam ring according to the hydraulic pressure introduced from the internal combustion engine; a control mechanism which controls the hydraulic pressure introduced into the first control oil chamber and the second control oil chamber; and a drain chamber partitioned with respect to the first control oil chamber and the second control oil chamber and which serves to generate a biasing force in a direction in which the volume variation quantity of the plurality of pump chambers is varied on a basis of the hydraulic pressure directly introduced from the drain section.
According to the present invention, oil drained from the drain section can be supplied to the internal combustion engine without intervention of an oil passage partitioned in an axial direction of first and second control oil chambers and superposed. Consequently, the large sizing of the axial direction of the pump can be avoided.
Hereinafter, each of preferred embodiments of a variable displacement oil pump according to the present invention will be described in details on a basis of the accompanied drawings. It should be noted that, in each of the preferred embodiments described below, this variable displacement oil pump is an application example of an oil pump to supply a lubricating oil of an internal combustion engine to a slide section of the engine of an automotive vehicle and to a valve timing control apparatus for a valve open and closure control for an engine valve.
It should herein be noted that the pump element is constituted by: a rotor 16 rotatably housed in an inner peripheral side of cam ring 15 and having a center section fitted to an outer peripheral surface of drive shaft 14; a plurality of vanes 17 housed to be projectable from and retractable within a plurality of slits 16a radially cut out on an outer peripheral section of rotor 16; and a pair of ring members 18, 18 disposed on both side sections of the inner peripheral side of rotor 16.
Pump body 11 is integrally formed of an aluminum alloy material. Especially, as shown in
A support groove 11b of laterally cross sectioned substantially semicircular shape is cut out at a predetermined position of an inner peripheral wall of pump housing chamber 13. This support groove 11b swingably supports cam ring 15 via a bar shaped pivot pin 19. Furthermore, a first seal slidably contact surface 13a is formed in a range corresponding to the absorption region which is an upper half side in
An introduction section 23 which is formed to protrude toward a spring housing chamber 28 side as will be described later is integrally installed at a substantially middle position of a peripheral direction of absorption port 21a. An absorption inlet 21b is penetrated through a proximity of a boundary section between introduction part 23 and absorption port 21a. Absorption inlet 21b penetrates through an end wall of pump body 11 and opens externally. According to the structure described above, oil reserved into an oil pan T of the internal combustion engine is absorbed into pump chamber PR related to the absorption region via absorption inlet 21b and absorption port 21a on a basis of a negative pressure generated according to the pump action by means of the pump element.
It should herein be noted that absorption inlet 21b is communicated with a low pressure chamber 35 formed in an outer peripheral area of cam ring 15 in the absorption region together with introduction section 23. Oil of a low pressure which is the absorption pressure is introduced into low pressure chamber 35.
On the other hand, a communication groove 24 constituting a drain passage by communicating drain port 22a with a drain chamber 36 as will be described later is cut out on the outer peripheral side of a start end section of drain port 22a, as shown in
In addition, absorption port 21a and drain port 22a are cut out at an inner side surface of cover member 12 in the same way as pump body 11. Another absorption port 21c and another drain port 22c structured in the same way as absorption port 21a and drain port 22a are opposed against absorption port 21a and drain port 22a. It should be noted that communication groove 24 and drain hole 25 are installed only at pump body 11 side.
An axial one end of drive shaft 14 which is penetrated through the end wall of pump body 11 to be exposed to the external is interlinked with the crankshaft (not shown) and rotates rotor 16 in a clockwise direction in
It should be noted that, as shown in
The plurality of slits 16a formed radially from the center side of rotor 16 toward an outside of the radial direction are cut out. Back pressure chambers 16b, each of back pressure chambers 61b being in a laterally cross sectioned surface of a substantially circular shape and each of which introduces drain oil, are installed at inside basic end sections of respective slits 16a. Each vane 17 is pushed out toward the external according to a centrifugal force due to the rotation of rotor 16 and a pressure within each back pressure chamber 16b.
Each vane 17 has a corresponding tip surface slidably contacted on an inner peripheral surface of cam ring 15 during the rotation of rotor 16 and has a corresponding base end surface slidably contacted on an outer peripheral surface of each ring member 18, 18. That is to say, each vane 17 is pushed up toward the outside of the radial direction of rotor 16 by means of each ring member 18, 18. Even if an engine revolution speed is low and the centrifugal force and the pressure of each back pressure chamber 16b are small (low), each tip of vanes 17 is slidably contacted on an inner peripheral surface of cam ring 15 so that each pump chamber PR is partitioned in a liquid tight manner.
Cam ring 15 is integrally formed in a substantially cylindrical shape by a, so-called, sintered metal. A pivot section 26 of a substantially arc recess groove shape which constitutes an eccentric swing fulcrum by fitting pivot section 26 into a pivot pin 19 is cut out along the axial direction of pump 10 at a predetermined position of the outer peripheral section of cam ring 15. In addition, an arm section 27 which interlinks with a coil spring 33 which is a biasing member set to a predetermined spring constant is projected along a radial direction of pump 10 at a position opposite to pivot section 26 via the center of cam ring 15. It should be noted that a pressing force projection section 27a formed in a substantially arc convex shape is projected at one side section of a movement (pivotal) direction of arm section 27. By contacting at all times pressing force projection section 27a on a tip of coil spring 33, arm section 27 is interlinked with coil spring 33.
A spring housing chamber 28 housing and holding coil spring 33 is installed adjacently to pump housing chamber 13 along the direction of cam ring eccentric direction line N in
It should be noted that the other end wall of spring housing chamber 28 is structured as a limitation section 29 which limits a movement range in the eccentric direction of cam ring 15. By contacting the other side section of arm section 27 on limitation section 29, a more movement in the eccentric direction of cam ring 15 is limited.
In this way, cam ring 15 is at all times biased toward a direction (the clockwise direction in
First, second, and third seal constituent sections 15a through 15c having concentric arc shaped seal surfaces with first, second, and third seal slidable contact surfaces 13a through 13c installed on the inner peripheral wall of pump housing chamber 13 are projected from the outer peripheral section of cam ring 15. Respective seal members 30 are housed and held on seal surfaces of respective seal constituent sections 15a through 15c.
It should be noted that each seal member 30 is formed to be elongated in the straight line manner along the axial direction of cam ring 15 by a fluorine-based resin material having, for example, a low frictional characteristic, backed up by a rubber made elastic member, and pressed against each seal slidable contact surface 13a through 13c. Thus, the partitioning is established in a liquid tight manner between each seal slidable contact surface 13a through 13c and the seal surface of each seal constituent section 15a through 15c.
In the seal structure described above, a pair of first and second control oil chambers 31, 32 are partitioned at an outer peripheral section of cam ring 15 by means of seal member 30 housed and held into first and second seal constituent sections 15a, 15b and pivot pin 19. A controlled pressure as will be described later as a hydraulic pressure within the internal combustion engine is introduced into first and second control oil chambers 31, 32 through a controlled pressure introduction passage 70 which is branched from main oil gallery MG. Specifically, the controlled pressure (hereinafter, simply called a “controlled pressure”) corresponding to the hydraulic pressure within the internal combustion engine which is a drain pressure of the pump decreased via a pass of an oil filter (not shown) is supplied to first control oil chamber 31 from control pressure introduction passage 70 via a first introduction passage 71 which is one of branch passages branched into two from control pressure introduction passage 70 and is supplied to second control oil chamber 32 via a second introduction passage 72 which is the other of the branch passages and solenoid valve 60.
In this way, a moving force (a swing force) for cam ring 15 is provided by acting the controlled pressure on a first pressure receiving surface 15d and a second pressure receiving surface 15e structured on the outer peripheral surface of cam ring 15 facing first and second control oil chambers 31, 32, respectively. It should herein be noted that a pressure receiving area of second pressure receiving surface 15e is larger (wider) than the pressure receiving area of first pressure receiving area 15d and is set to be smaller (narrower) than the pressure receiving area which is a sum of the pressure receiving area of first pressure receiving area 15d and the pressure receiving area of third pressure receiving surface 15f as will be described later. In a case where the same hydraulic pressure is acted on each pressure receiving surface 15d through 15f, cam ring 15 is biased in a direction in which, as a whole, its eccentricity is reduced (in a counterclockwise direction in
A drain chamber 36 is partitioned by means of seal member 30 housed and held in third seal constituent section 15c and pivot pin 19 between the peripheral direction of first control oil chamber 31 and second control oil chamber 32. A pump drain pressure itself (hereinafter, called simply, a “pump drain pressure”) drained from the pump element is introduced via a communication groove 24 into drain chamber 36. By acting the pump drain pressure on third pressure receiving surface 15f, cam ring 15 is biased in the concentric direction in cooperation with first control oil chamber 31.
In the structure as described above, in oil pump 10, when a biasing force based on an inner pressure of first, second control oil chambers 31, 32 and drain chamber 36 with respect to set weight W1 of coil spring 33 is small, cam ring 15 becomes the maximum eccentric state shown in
Pilot valve 40 is, as shown in
A straight body figure valve housing section 41a is drilled in a range of valve body other than axial directional both end sections and constituting an inner diameter substantially the same diameter as an outer diameter of spool valve body 43 (an outer diameter of each land section 43a, 43b). Spool valve body 43 is housed within valve housing section 41a. Introduction port 50 is opened at axial one end section of valve body 41. Introduction port 50 serves to introduce the control pressure by connecting to first introduction passage 71. A plug 42 is screwed to the other end section of valve body 41 via a female screw section formed on an inner peripheral section of the other end section.
A first connection port 51 is opened which is connected to first control oil chamber 31 at axial one end side position of a peripheral wall of valve housing section 41a. A second connection port 52 is opened which is connected to second control pressure chamber 32 at a intermediate position in the axial direction. A supply/exhaust port 53 which serves to supply and exhaust the hydraulic pressure to second control oil chamber 32 is opened by connecting to solenoid valve 60 via a passage 72b (hereinafter called simply “downstream side passage) at a downstream side of second introduction passage 72. A drain port 54 which serves to exhaust the hydraulic pressure of first and second control oil chambers 31, 32 introduced via an internal passage 55 as will be described later is opened at the axial other end side position.
Spool valve body 43 has axial both end sections on which first and second land sections 43a, 43b are formed and a small diameter axle section 43c is interlinked between both first and second land sections 43a, 43b. This spool valve body 43 is housed within valve housing section 41a. Therefore, at an inside of valve housing section 41a, a pressure chamber 56 interposed between first land section 43a and valve body 41 and to which the control pressure is introduced via introduction port 50, a relay chamber 57 interposed between both land sections 43a, 43b and which serves to relay between second connection port 52 and supply/exhaust port 53 as will be described later, and aback pressure chamber 58 interposed between second land section 43b and plug 42 and which serves to exhaust the hydraulic pressure introduced via an internal passage 55 as will be described later are respectively partitioned.
In addition, internal passage 55 which serves to exhaust the hydraulic pressure within first control oil chamber 31 is structured in the inside of spool valve body 43. Internal passage 55 is drilled in a step difference reduced diameter form from the axial other end side. That is to say, this internal passage 55 has a small diameter section 55a formed at one end side of internal passage 55 and communicated with a first connection port 51 via a plurality of communication holes 59 and an annular groove 59a connecting communication holes 59 in a state in which spool valve body 43 is placed at an upper end side position in
In the structure described above, in pilot valve 40, spool valve body 43 is pressed toward one end side of valve housing section 41a (refer to
When the control pressure introduced to pressure chamber 56 is in excess of the predetermined pressure, spool valve body 43 is moved to the other end side of valve housing chamber 41a against the biasing force of valve spring 44 (refer to
Solenoid valve 60 is, as shown in
In valve body 61, valve body housing section 66 is installed in a step difference increase diameter shape with respect to oil passage 65. Valve body housing section 66 houses a ball valve body 63 in an inner peripheral, section at the one end side of valve body 61. A valve seat 66a which is the same as a valve seat 62a installed on seat member 62 is formed on an opening edge of an inner end section of valve body housing section 66. Furthermore, supply/exhaust port 68 connected to downstream side passage 72b and which serves to supply or exhaust of the hydraulic pressure with respect to pilot valve 40 is penetrated along the radial direction at an outer peripheral section of valve body housing section 66 which is the one end section in the axial direction from among peripheral walls of this valve body 61. A drain port 69 connected to oil pan T is penetrated along a radial direction at an outer peripheral section of oil passage 65 which is the axial other side of the peripheral wall of valve body 61.
Solenoid 64 is constituted by an armature (not shown) arranged at the inner peripheral side of a coil and a rod 64b fixed to the armature which are advanced and moved in a left side direction in
In the structure described above, when the exciting current is caused to flow through solenoid 64, rod 64b is advanced and moved, ball valve body 63 arranged at the tip of rod 64b is pressed toward valve seat 62a of seat member 62 side, the communication between introduction port 67 and supply/exhaust port 68 is interrupted, and supply/exhaust port 68 and drain port 69 are communicated via oil passage 65. On the other hand, when the exciting current is not caused to flow through solenoid 64, ball valve body 63 is retracted and moved on a basis of the control pressure introduced from introduction port 67. Thus, ball valve body 63 is pressed toward valve seat 66a of the valve body 61 side. Introduction port 67 and supply/exhaust port 68 are communicated and the communication between supply/exhaust port 68 and drain port 69 is interrupted.
Hereinafter, a characteristic action on an oil pump 10 related to the first embodiment will be explained on a basis of
(Solenoid OFF)
In a state in which the engine revolution speed is low, the exciting current is caused to flow through solenoid 64. As shown in
Consequently, first land section 43a interrupts the communication between first connection port 51 and pressure chamber 56. First connection port 51 and internal passage 55 are communicated. The oil within first control oil chamber 31 is exhausted into oil pan T via internal passage 55, drain port 54, and so forth. The oil within second control oil chamber 32 is exhausted into oil pan T via relay chamber 57, supply/exhaust port 53, solenoid valve 60, and so forth. Thus, the hydraulic pressure is not acted on first and second control oil chambers 31, 32 and both of first and second control oil chambers 31, 32 provide the atmospheric pressure. The hydraulic pressure (pump drain pressure) is acted only on drain chamber 36 which is directly communicated with drain port 22a. Consequently, cam ring 15 is held in a maximum eccentric state and pump drain pressure P is increased in a form of a substantial proportional to engine revolution speed R (interval of a in
Thereafter, engine revolution speed R is raised and pump drain pressure P reaches to cam ring operation hydraulic pressure Pc (refer to
Then, due to the decrease in this pump drain pressure P, the hydraulic pressure acted on the one end of spool valve body 43 is reduced below cam ring operation hydraulic pressure Pc. Cam ring 15 is moved in the concentric direction according to biasing force W1 of coil spring 33. Spool valve body 43 is moved to introduction port 50 side (first position). The eccentricity of cam ring 15 is returned to a state of
(Solenoid ON)
In a state in which the engine revolution speed is high, the exciting current to solenoid 64 is interrupted. As shown in
Consequently, first connection port 51 is communicated with introduction port 50 via pressure chamber 56 and second connecting port 52 is communicated with supply/exhaust port 53 via relay chamber 57. Thus, the control pressure is supplied to first control oil chamber 31 via throttle V and the control pressure introduced from second introduction passage 72 is supplied to second control oil chamber 32. Each control pressure is acted on first and second control oil chambers 31, 32 and the pump drain pressure is acted on drain chamber 36. Consequently, the biasing force in the eccentric direction constituting a synthesized force between biasing force W1 of coil spring 33 and the biasing force based on the internal pressure of second control oil chamber 32 is in excess of the biasing force in the concentric direction based on both internal pressures of first control oil chamber 31 and drain chamber 36, cam ring 15 is in the maximum eccentric state and pump drain pressure P is increased in a form of substantially proportional to engine revolution speed R (an interval c in
Thereafter, when the engine revolution speed R is raised and pump drain pressure P reaches to spool operation hydraulic pressure Ps (refer to
Then, due to the decrease of this pump drain pressure P, the hydraulic pressure acted on one end of spool valve body 43 is below spool operation hydraulic pressure Ps. Spool valve body 43 is moved toward introduction port 50 side (second position) by means of biasing force W2 of valve spring 44. Second connection port 52 is communicated with supply/exhaust port 53 so that the control pressure is again supplied to second control oil chamber 32. Consequently, cam ring 15 is pushed back toward the eccentric direction and is returned to a state of
As described above, in oil pump 10 related to the first embodiment, oil can be supplied to the internal combustion engine via drain chamber 36 partitioned with respect to first and second control oil chambers 31, 32 and directly communicated with drain port 22a. The oil drained from drain port 22a can be supplied to the internal combustion engine without intervention of the oil passage partitioned and superposed in the axial direction of first and second control oil chambers 31, 32. Thus, a large sizing in the axial direction of oil pump 10 can be avoided by the oil passage and the partitioning wall partitioning this oil passage.
In addition, since drain hole 25 is superposed on drain chamber 36, a small sizing in the radial direction of oil pump 10 can be achieved. Oil pump 10 can further be compacted.
In addition, in the first embodiment, drain chamber 36 is structured at the position at which the biasing force is generated in the concentric direction and which is a start end side of drain port 22a. Oil can, at an earlier timing, be drained. In addition, the swing force in the eccentric direction of cam ring 15 acted on a basis of the internal pressure of pump chamber PR can be cancelled by the internal pressure of pump chamber PR based on the pump drain pressure which is higher than the control pressure. Consequently, a reduction of an operation delay of cam ring 15 can be achieved under a situation under which the internal pressure of pump chamber PR can be raised when the engine is a high revolution speed, a low oil temperature, and so forth.
In the second embodiment, drain hole 25 is installed outside of drain chamber 36.
It should be noted that, in each of
That is to say, in oil pump 80 according to the second embodiment, a substantially cylindrical passage constituent section 81 is radially outwardly extended on the peripheral wall of pump housing chamber 13 of pump body 11. Passage constituent section 81 is communicable with drain chamber 36. A drain passage 82 is provided at an inside of this passage constituent section 81. This drain passage 82 serves to drain oil toward oil main gallery MG. Drain hole 25 which axially opens toward pump body 11 is penetrated at the outer end side of drain passage 82. It should be noted that a reference numeral 83 in
In this way, since, in the second embodiment, especially, drain passage 82 is used to offset drain hole 25 outside of drain chamber 36, an improvement of a degree of freedom of the layout of drain hole 25 can be achieved. A versatility of oil pump 80 can furthermore be enhanced.
That is to say, in oil pump 90 in the third embodiment, a passage constituent section 91 is radially outwardly extended on the peripheral wall of pump housing chamber 13 of pump body 11. This passage constituent section 91 is communicable with drain chamber 36. This passage constituent section 91 is opened toward drain chamber 36 side and opened toward cover member 12 side. A junction of cover member 12 constitutes a substantially cylindrical drain passage 92 at an inside of cover member 12. Then, in the third embodiment, drain hole 25 is penetrated through cover member 12. Drain hole 25 serves to drain the oil introduced through drain passage 92 by opening to an outside end section of drain passage 92. The drain oil is taken out from cover member 12 side.
In this way, the third embodiment can basically achieve the same action and effect as the second embodiment. Especially, the third embodiment becomes optimum for a layout taking out the drained oil from cover member 12 side.
That is to say, in oil pump 100 according to the fourth embodiment, a third seal constituent section 15c of cam ring 15 and a third seal slidably contact surface 13c of pump housing chamber 13 are installed at positions below cam ring reference line M so that drain chamber 36 is partitioned at a position below same cam ring reference line M and an internal pressure of drain chamber 36 is acted in the eccentric direction. It should be noted that, in order to meet the arrangement of drain chamber 36, communication groove 24 and drain hole 25 are arranged at a terminal end side of drain port 22a which is below cam ring reference line M.
In this way, in the fourth embodiment, especially, drain chamber 36 is structured at a position at which the biasing force is generated toward the eccentric direction, namely, at a position of the end side of drain port 22a at which an internal volume of pump chamber PR is made small and the internal pressure is more higher. The rise of the internal pressure at a narrow part of pump chamber PR can be suppressed due to the internal pressure of drain chamber 36 based on the pump drain pressure higher than the control pressure. Consequently, reductions of a wasteful work and noise of oil pump 100 can be achieved.
The present invention is not limited to the structures disclosed in the respective embodiments. For example, an engine required hydraulic pressure, cam ring operation hydraulic pressure Pc, spool operation hydraulic pressure Ps, specific structures of pilot valve 40 and solenoid valve 60, and handling of the oil passage can freely be modified in accordance with specifications of the vehicular internal combustion engine in which oil pump 10 is mounted, the valve timing control apparatus, and so forth.
In addition, in the above-described embodiments, the drain quantity is variable by swinging cam ring 15. However, as means for varying the drain quantity, not only the means related to the swing, but may be carried out by moving cam ring 15 straightly in the radial direction. In other words, if the structure which can modify the drain quantity (structure which can modify the volume variation quantity of pump chambers PR), a form of the movement of cam ring 15 does not matter.
In the respective embodiments, the variable displacement vane pump is exemplified. Cam ring 15 is exemplified as a movable member according to the present invention. A variable mechanism is constituted by cam ring 15 swingably disposed, first and second control oil chambers 31, 32, drain chamber 36, and coil spring 33. In a case where the present invention is applied to another type of the variable displacement oil pump, for example, a trochoid pump, an outer rotor constituting an external gear corresponds to the movable member. Then, the outer rotor is disposed eccentrically movably in the same way as cam ring 15 and the control oil chamber and the spring are disposed at the outer peripheral side of the outer rotor to constitute the variable mechanism.
Hereinafter, technical ideas graspable from the respective preferred embodiments will be explained.
(a) The variable displacement oil pump as set forth in claim 4, wherein the pump element is housed in a pump housing having a pump housing chamber formed in a bottomed cylindrical shape, the drain passage is formed integrally with the pump housing, and the drain hole is installed in the pump housing.
(b) The variable displacement oil pump as set forth in claim 4, wherein the pump element is housed in a pump housing constituted by a pump body having a pump housing chamber whose one end side is opened and formed in a substantially bottomed cylindrical shape and a cover member joined to the pump body and which closes one end side opening section of the pump housing chamber, the drain passage is formed integrally with the pump body, and the drain hole is installed in the cover member.
(c) The variable displacement oil pump as set forth in claim 1, wherein a part of the control mechanism is constituted by a pilot valve.
(d) The variable displacement oil pump as set forth in claim 6, wherein the first control oil chamber and the second control oil chamber are arranged at an outer peripheral side of the cam ring and are partitioned by a swing fulcrum of the cam ring installed on the outer peripheral side of the cam ring.
(e) The variable displacement oil pump as set forth in item (d), wherein the drain chamber is installed to be communicated with the drain section at the outer peripheral section at the outer peripheral side of the cam ring.
This application is based on a prior Japanese Patent Application No. 2014-242716 filed in Japan on Dec. 1, 2014. The entire contents of this Japanese Patent Application No. 2014-242716 are hereby incorporated by reference. Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiment described above. Modifications and variations of the embodiments described above will occur to those skilled in the art in light of the above teachings. The scope of the invention is defined with reference to the following claims.
Number | Date | Country | Kind |
---|---|---|---|
2014-242716 | Dec 2014 | JP | national |