Variable displacement oil pump

Abstract

This variable-capacity oil pump (VP1) comprises a stopper section (45) that can come into contact with a cam ring contact section (112e) disposed on a pump accommodation section (110), the stopper section being disposed at a position that does not overlap, in a circumferential direction around the rotational center (Z) of a drive shaft (2), with a first intake port (114), a second intake port (124), and an intake opening (124a) that are equivalent to an intake section. Consequently, the stopper section (45) is not prone to blocking the flow of oil taken into a pump chamber (30) of an intake region via the first intake port (114), the second intake port (124), and the intake opening (124a), and the intake capabilities of the pump can be improved.

Description

[Technical Field]

[0001] The present invention relates to a variable displacement oil pump. [Background technology]

[0002] A conventional variable displacement oil pump is known, for example, from Patent Document 1 below.

[0003] In the variable displacement oil pump described in Patent Document 1, the cam ring is constantly urged in a direction that increases the amount of eccentricity by the urging force of a coil spring, which is a urging member, via an arm portion extending outward from the cam ring. A stopper portion provided on the side surface of the arm portion in the eccentric direction abuts against a stopper abutment portion provided on the inner peripheral wall of the housing, thereby restricting further movement of the cam ring in the eccentric direction and maintaining the maximum eccentric state. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-104968 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional variable displacement oil pump, the arm portion of the cam ring that constitutes the stopper portion is positioned so as to overlap with the intake portion (intake port or intake port) that draws oil into the pump housing. As a result, the arm portion of the cam ring increases intake resistance, reducing the pump's intake performance, leaving room for improvement.

[0006] Therefore, the present invention has been devised in consideration of the technical problems with the conventional variable displacement oil pumps described above, and has an object to provide a variable displacement oil pump that can improve the suction performance of the pump. [Means for solving the problem]

[0007] In one aspect of the present invention, the stopper portion is provided at a position that does not overlap with the suction portion in the circumferential direction of the rotation center of the drive shaft. [Effects of the Invention]

[0008] According to the present invention, it is possible to reduce the inhalation resistance. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an exploded perspective view of a variable displacement oil pump according to a first embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view of the variable displacement oil pump shown in FIG. 1, as viewed from the front side. [Figure 3] FIG. 2 is a perspective view of the variable displacement oil pump shown in FIG. 1, as viewed from the rear side. [Figure 4] 4 is a plan view showing the variable displacement oil pump shown in FIG. 3 with a second housing removed. FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. [Figure 6] 2 is a view of the first housing shown in FIG. 1 as seen from the mating surface side with the second housing. [Figure 7] 2 is a view of the second housing shown in FIG. 1 as seen from the mating surface side with the first housing. [Figure 8] 4 is a graph showing the discharge oil pressure characteristics of a variable displacement oil pump according to the present invention. [Figure 9] 8A and 8B are hydraulic circuit diagrams showing the operating state of the variable displacement oil pump according to the first embodiment of the present invention, where FIG. 8A shows the state of the pump in section a of FIG. 8 and FIG. 8B shows the state of the pump in section b of FIG. 8. [Figure 10] 9A and 9B are hydraulic circuit diagrams showing the operating state of the variable displacement oil pump according to the first embodiment of the present invention, where FIG. 9A shows the state of the pump in section c of FIG. 8 and FIG. 9B shows the state of the pump in section d of FIG. 8. [Figure 11]9A and 9B are hydraulic circuit diagrams showing the operating state of the variable displacement oil pump according to the first embodiment of the present invention, where FIG. 9A shows the state of the pump in section e of FIG. 8 and FIG. 9B shows the state of the pump in section f of FIG. 8. [Figure 12] FIG. 10 is a plan view showing a variable displacement oil pump according to a second embodiment of the present invention with a second housing removed. [Figure 13] 8A and 8B are hydraulic circuit diagrams showing the operating state of a variable displacement oil pump according to a modified example of the first embodiment of the present invention, where FIG. 8A shows the state of the pump in section a of FIG. 8 and FIG. 8B shows the state of the pump in section b of FIG. 8. [Figure 14] 9A and 9B are hydraulic circuit diagrams showing the operating state of a variable displacement oil pump according to a modified example of the first embodiment of the present invention, where FIG. 9A shows the state of the pump in section c of FIG. 8 and FIG. 9B shows the state of the pump in section d of FIG. 8. [Figure 15] 9A and 9B are hydraulic circuit diagrams showing the operating state of a variable displacement oil pump according to a modified example of the first embodiment of the present invention, where FIG. 9A shows the state of the pump in section e of FIG. 8 and FIG. 9B shows the state of the pump in section f of FIG. 8. [Figure 16] FIG. 10 is a plan view showing a variable displacement oil pump according to a second embodiment of the present invention with a second housing removed. [Figure 17] FIG. 10 is a plan view showing a variable displacement oil pump according to a third embodiment of the present invention with a second housing removed. [Figure 18] FIG. 10 is a plan view showing a variable displacement oil pump according to a fourth embodiment of the present invention with a second housing removed. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a variable displacement oil pump according to the present invention will be described in detail below with reference to the drawings. In the following embodiment, the variable displacement oil pump is used as an oil pump for supplying lubricating oil to a valve timing control device for controlling the opening and closing timing of sliding parts and engine valves in an automotive internal combustion engine. For convenience, the following description will define the direction along the rotational axis of the drive shaft 2 as the "axial direction," the direction perpendicular to the rotational axis of the drive shaft 2 as the "radial direction," and the rotational direction of the drive shaft 2 as the "circumferential direction."

[0011] [First embodiment] Figures 1 to 11 show a variable displacement oil pump VP1 according to a first embodiment of the present invention. Figures 1 to 7 are diagrams showing the configuration of the variable displacement oil pump VP1, and Figures 8 to 11 are diagrams explaining the variable displacement control of the variable displacement oil pump VP1.

[0012] (Oil pump configuration) 1, variable displacement oil pump VP1 has a drive shaft 2, a pump member 3 that is rotationally driven by the drive shaft 2, a cam ring 4 that corresponds to an adjustment member that is swingably provided on the outer periphery of the pump member 3, and a coil spring SP that corresponds to a biasing member that biases the cam ring 4, all of which are housed inside a housing 1. In this embodiment, variable displacement oil pump VP1 is fastened to an engine (not shown), specifically to the side of a cylinder block (not shown), by bolts (not shown).

[0013] 1, the housing 1 has a cup-shaped first housing 11 that corresponds to the pump body, and a lid-shaped second housing 12 that is joined to the first housing 11 and corresponds to a cover member that closes the opening of the first housing 11. The first housing 11 and the second housing 12 are both integrally formed from a metal material, for example, an aluminum alloy.

[0014] 1 and 6 , the first housing 11 has a bottom wall 111 and a peripheral wall 112 that rises from the outer peripheral edge of the bottom wall 111 and continues circumferentially along the outer peripheral edge of the bottom wall 111. That is, the first housing 11 is open at one axial end that faces the second housing 12, and is closed at the other axial end by the bottom wall 111. In other words, the bottom wall 111 and the peripheral wall 112 define a cup-shaped pump accommodating portion 110 inside the first housing 11.

[0015] 1 to 4 and 6, the first housing 11 is provided at an opening edge on one axial end thereof with a brim-shaped flange 113 for joining to the second housing 12. The flange 113 is provided to extend radially outward from the first housing 11 and is formed integrally with the peripheral wall 112. The flange 113 also has a plurality of female threaded holes 113a. These female threaded holes 113a are provided at intervals in the circumferential direction, and a plurality of screws SW for fastening the second housing 12 to the first housing 11 are screwed into each female threaded hole 113a. The flange 113 also has a plurality of first housing side mounting holes 113b. These first housing side mounting holes 113b are provided at intervals in the circumferential direction, and together with a second housing side mounting hole 121b provided in the second housing 12, form pump mounting holes for mounting the variable displacement oil pump VP1 to the cylinder block (not shown).

[0016] A first bearing hole 111a that rotatably supports one end of the drive shaft 2 penetrates substantially at the center of the bottom wall 111 that constitutes one end wall of the pump housing portion 110. Furthermore, a first pin support groove 111b that swingably supports the cam ring 4 via a cylindrical pivot pin 40 is formed on the inner surface of the bottom wall 111.

[0017] 6, a first seal sliding surface 112a, with which the first seal member S1 provided on the outer periphery of the cam ring 4 slides, is formed on the inner surface of the peripheral wall 112, above a line M (hereinafter referred to as the "cam ring reference line") connecting the center of the first bearing hole 111a and the center of the first pin support groove 111b. The first seal sliding surface 112a is formed in the shape of an arcuate surface having a curvature defined by a first radius R1 from the center of the first pin support groove 111b. The circumferential length of the first seal sliding surface 112a is set to a length that allows the first seal member S1 to always slide against the first seal sliding surface 112a within the swing range of the cam ring 4.

[0018] Similarly, second seal sliding contact surface 112b and third seal sliding contact surface 112c, with which second seal member S2 and third seal member S3 provided on the outer periphery of cam ring 4 slide, are formed below cam ring reference line M in Fig. 6. Second seal sliding contact surface 112b is formed as an arcuate surface having a curvature determined by a second radius R2 from the center of first pin support groove 111b, and third seal sliding contact surface 112c is formed as an arcuate surface having a curvature determined by a third radius R3 from the center of first pin support groove 111b. Second seal sliding contact surface 112b has a circumferential length set to allow constant sliding contact with second seal member S2 within the pivoting range of cam ring 4, and third seal sliding contact surface 112c has a circumferential length set to allow constant sliding contact with third seal member S3 within the pivoting range of cam ring 4.

[0019] 6, a cam ring abutment portion 112e corresponding to a stopper abutment portion that abuts against a stopper portion 45 (described later) provided on cam ring 4 is formed on the inner surface of peripheral wall 112, between first seal sliding surface 112a and second seal sliding surface 112b. This cam ring abutment portion 112e is provided within a region that corresponds to a suction-side chamber IH (described later) and at a position that does not overlap with first suction port 114, second suction port 124 (described later), and suction opening 124a that constitute the suction portion according to the present invention.

[0020] The cam ring abutment portion 112e has a flat shape that can abut against the stopper portion 45 over almost the entire surface when the cam ring 4 is at its maximum eccentricity, thereby restricting the maximum amount of eccentricity of the cam ring 4. In other words, when the cam ring 4 moves in the eccentric direction described below, the stopper portion 45 abuts against the cam ring abutment portion 112e, thereby restricting the maximum amount of eccentricity of the cam ring 4. Furthermore, the cam ring abutment portion 112e is formed by a flat surface that is approximately perpendicular to the biasing direction of the coil spring SP (the direction along line Y in FIG. 4 ) and is parallel to the spring abutment portion 440 and the stopper abutment surface 450 when the cam ring 4 is at its maximum eccentricity. The cam ring abutment portion 112e is formed by machining, together with the first, second, and third seal sliding surfaces 112a, 112b, and 112c, using a cutting tool such as an end mill that is used to machine the peripheral wall 112 of the pump housing portion 110.

[0021] As shown in FIG. 6, the inner surface of the peripheral wall 112 is formed with a recess 112f between the cam ring contact portion 112e and the second seal sliding surface 112b by recessing the pump housing portion 110 radially outward. The recess 112f is generally arc-shaped and is located adjacent to the cam ring contact portion 112e. The recess 112f has a radius of curvature greater than the radius of an end mill (not shown) used to machine the cam ring contact portion 112e. This allows the recess 112f to function as a clearance for the end mill when the end mill is moved from the first seal sliding surface 112a to the second seal sliding surface 112b to machine the cam ring contact portion 112e.

[0022] 4 and 6, a first suction port 114 having a generally arc-like shape is formed on the inner surface of the bottom wall 111, on the outer circumferential side of the first bearing hole 111a, so as to open into a region (hereinafter referred to as the "suction region") where the volumes of the plurality of pump chambers 30 described below increase with the pumping action of the pump member 3. On the other hand, a first discharge port 115 having a generally arc-like shape is formed on the opposite side of the rotation center Z of the drive shaft 2 from the suction region so as to open into a region (hereinafter referred to as the "discharge region") where the volumes of the plurality of pump chambers 30 described below decrease.

[0023] As shown in FIG. 6, the first suction port 114 is narrowest at its starting end and widest at its middle portion in the rotational direction D of the drive shaft 2, gradually narrowing from the middle portion toward the terminal end. Oil stored in the engine's oil pan OP is introduced into the first suction port 114 through a suction port 124a (described later) provided in the second housing 12. In this manner, in the variable displacement oil pump VP1, as shown in FIG. 4, oil stored in the engine's oil pan OP is drawn into each pump chamber 30 associated with the suction region through the suction port 124a, the first suction port 114, and a second suction port 124 (described later) by negative pressure generated by the pumping action of the pump member 3. In this manner, the first suction port 114, the second suction port 124 (described later), and the suction port 124a (described later) constitute an suction section according to the present invention.

[0024] As shown in FIG. 6, the first discharge port 115 is formed so as to gradually widen from its starting end toward its terminal end in the rotational direction D of the drive shaft 2. A discharge port extension 115a extending radially outward is provided contiguous with the terminal end of the first discharge port 115. A discharge port outlet 115b penetrating the bottom wall 111 and opening to the outside is provided at the tip of the discharge port extension 115a. In this manner, as shown in FIG. 4, in the variable displacement oil pump VP1, oil pressurized by the pumping action of the pump member 3 and discharged to the first discharge port 115 and a second discharge port 125 (described later) is supplied from the discharge outlet 115b through a main gallery MG provided inside a cylinder block (not shown) to various sliding parts of the engine (e.g., a crank metal CM), an oil jet device OJ (not shown) that cools pistons of the engine (not shown), a valve timing control device VT (not shown), and the like. In this way, the first discharge port 115, the second discharge port 125 (described later), and the discharge opening 115b constitute a discharge section according to the present invention.

[0025] 1 to 3 and 7, the second housing 12 functions as a lid-like cover member that closes an opening on one end side of the first housing 11, and is joined to the flange portion 113 of the first housing 11 via a plurality of screws SW. Specifically, the second housing 12 has a plurality of screw through holes 121a provided at positions corresponding to the female threaded holes 113a of the first housing 11. The second housing 12 is fastened to the first housing 11 by threading the plurality of screws SW that pass through the plurality of screw through holes 121a into the female threaded holes 113a of the first housing 11.

[0026] 7, second housing 12 is formed with a second bearing hole 122a penetrating therethrough at a position opposite first bearing hole 111a of first housing 11, for rotatably supporting the other end of drive shaft 2. Second pin support groove 122b, second suction port 124, and second discharge port 125 corresponding to first pin support groove 111b, first suction port 114, and first discharge port 115 of first housing 11 are also disposed on the inner surface of second housing 12, facing first pin support groove 111b, first suction port 114, and first discharge port 115. An intake port 124a is provided at the beginning of second suction port 124, penetrating the bottom of second suction port 124 and opening to the outside. Suction port 124a may be directly connected to an oil pan OP via an oil strainer (not shown), or may be connected to the oil pan OP via an intake passage (not shown).

[0027] Furthermore, a communication groove 123 that connects the second discharge port 125 and the second bearing hole 122a is provided on the inner surface of the second housing 12. That is, oil is supplied to the second bearing hole 122a via this communication groove 123, and also to the side portions of the rotor 31 and each vane 32 described below, ensuring good lubrication of each sliding portion. Note that this communication groove 123 is formed so as not to coincide with the direction in which each vane 32 described below appears and disappears, thereby preventing each vane 32 from falling off into the communication groove 123.

[0028] As shown in FIGS. 1 to 4, the drive shaft 2 has a large-diameter portion 21 formed with a relatively large diameter at one axial end thereof, which is rotatably supported in a first bearing hole 111a of the first housing 11. Meanwhile, a general-diameter portion 22, which has a smaller outer diameter than the large-diameter portion 21, at the other axial end thereof is rotatably supported in a second bearing hole 122a of the second housing 12. Furthermore, a drive shaft end portion 23 of the drive shaft 2, which is formed with a relatively smaller diameter at one end closer to the large-diameter portion 21 than the large-diameter portion 21, faces the outside through the first bearing hole 111a and is connected to a crankshaft of an engine (not shown) via a transmission member (not shown), such as a chain. In other words, the drive shaft 2 rotates the pump member 3 in a rotational direction D in FIG. 4 based on the rotational force transmitted from the crankshaft (not shown). Here, a straight line N (hereinafter referred to as the "cam ring eccentricity direction line") shown in Figure 4, which passes through the rotation center Z of the drive shaft 2 and is perpendicular to the cam ring reference line M, is the boundary between the suction area and the discharge area.

[0029] 1 and 4, the pump member 3 has a rotor 31 housed on the inner peripheral side of the cam ring 4 and rotated by the drive shaft 2, and a plurality of vanes 32 housed so as to be able to protrude and retract within a plurality of slits 312 cut out radially on the outer peripheral side of the rotor 31. In addition, a pair of ring members 33, 33 formed with a smaller diameter than the rotor 31 and housed radially inside each vane 32 are disposed on both axial ends of the rotor 31.

[0030] 1 and 4, rotor 31 has a shaft through hole 311 penetrating through the center along the axial direction, and has a plurality of slits 312 cut out radially from the center of shaft through hole 311 outward in the radial direction. In addition, back pressure chambers 313 having a substantially circular cross section and for introducing oil are provided at the bottom of each slit 312. That is, each vane 32 is pushed outward (toward cam ring 4) by the centrifugal force generated as rotor 31 rotates and the pressure of oil introduced into back pressure chambers 313.

[0031] The plurality of vanes 32 housed in the rotor 31 are formed in a rectangular plate shape from a predetermined metal material, and as the rotor 31 rotates, the tip end surface of each vane 32 slides against the inner circumferential surface of the cam ring 4. That is, as the tip end surface of each vane 32 slides against the inner circumferential surface of the cam ring 4, the rotor 31, a pair of circumferentially adjacent vanes 32, 32, and the cam ring 4 define a plurality of pump chambers 30 in the rotation direction D of the rotor 31. As the rotor 31 rotates, the base end surface of each vane 32 slides against the outer circumferential surfaces of a pair of ring members 33, 33, and the vanes 32 are pushed radially outward from the rotor 31 by the pair of ring members 33, 33. As a result, even when the engine speed is low and the centrifugal force caused by the rotation of the rotor 31 and the hydraulic pressure in the back pressure chamber 313 are small, the tip end surface of each vane 32 slides against the inner circumferential surface of the cam ring 4, thereby separating the pump chambers 30 liquid-tightly.

[0032] The cam ring 4 is made of a sintered material and has a generally annular shape. The inner periphery of the cam ring 4 has a circular pump member accommodating portion 41 that can accommodate the pump member 3. The outer periphery of the cam ring 4 has a cylindrical swing support portion 42 that extends along the axial direction. A pin through hole 420 is formed in the swing support portion 42 and penetrates the axial direction. Specifically, the cam ring 4 is swingably supported within the pump accommodating portion 110 via a cylindrical pivot pin 40 that penetrates the pin through hole 420 and is supported in the first pin support groove 111b and the second pin support groove 122b. In this embodiment, the swing support portion 42 has a cylindrical shape and completely surrounds the outer periphery of the pivot pin 40. The swing support portion 42 is pressed against the peripheral wall 112 of the pump accommodating portion 110 by the discharge pressure P acting on the inner surface of the cam ring 4 (pump member accommodating portion 41) in the discharge region. That is, a support tip surface 421 provided on the opposite side of the pivot pin 40 from the pump member accommodating portion 41 slides against the peripheral wall 112 of the pump accommodating portion 110 when the cam ring 4 swings.

[0033] Additionally, the outer circumferential side of cam ring 4 has first seal component 431, second seal component 432, and third seal component 433, which respectively face first seal sliding surface 112a, second seal sliding surface 112b, and third seal sliding surface 112c of first housing 11. First seal component 431 has a first seal surface 431a shaped like an arc concentric with first seal sliding surface 112a. Second seal component 432 has a second seal surface 432a shaped like an arc concentric with second seal sliding surface 112b. Third seal component 433 has a third seal surface 433a shaped like an arc concentric with third seal sliding surface 112c.

[0034] Furthermore, a first seal holding groove 431b is formed in the first seal surface 431a, extending along the axial direction and opening toward the first seal sliding contact surface 112a. A second seal holding groove 432b is formed in the second seal surface 432a, extending along the axial direction and opening toward the second seal sliding contact surface 112b. A third seal holding groove 433b is formed in the third seal surface 433a, extending along the axial direction and opening toward the third seal sliding contact surface 112c.

[0035] The first seal retaining groove 431b accommodates a first seal member S1 that comes into sliding contact with the first seal sliding surface 112a when the cam ring 4 pivots. The second seal retaining groove 432b accommodates a second seal member S2 that comes into sliding contact with the second seal sliding surface 112b when the cam ring 4 pivots. The third seal retaining groove 433b accommodates a third seal member S3 that comes into sliding contact with the third seal sliding surface 112c when the cam ring 4 pivots.

[0036] 4, the first seal surface 431a has a predetermined radius slightly smaller than the first radius R1 of the first seal sliding surface 112a, forming a small clearance between the first seal surface 431a and the first seal sliding surface 112a. The second seal surface 432a has a predetermined radius slightly smaller than the second radius R2 of the second seal sliding surface 112b, forming a small clearance between the second seal surface 432a and the second seal sliding surface 112b. The third seal surface 433a has a predetermined radius slightly smaller than the third radius R3 of the third seal sliding surface 112c, forming a small clearance between the third seal surface 433a and the third seal sliding surface 112c.

[0037] 1 and 4, the first seal member S1, the second seal member S2, and the third seal member S3 are all made of, for example, a fluorine-based resin material having low friction properties, and are formed linearly and elongated along the axial direction of the cam ring 4. Furthermore, as shown in Fig. 4, a rubber elastic member BR is disposed at the bottom of each of the first seal retaining groove 431b, the second seal retaining groove 432b, and the third seal retaining groove 433b. That is, the first, second, and third seal members S1, S2, and S3 elastically contact the first, second, and third seal sliding surfaces 112a, 112b, and 112c, respectively, with the elastic force of the elastic members BR, thereby providing a liquid-tight seal between the first, second, and third seal surfaces 431a, 432a, 433a and the first, second, and third seal sliding surfaces 112a, 112b, and 112c.

[0038] 4, a first control oil chamber PR1 is defined on the outer periphery of cam ring 4 by swing support member 42, which is supported via pivot pin 40, and first seal member S1. A first control oil pressure P1 is introduced into first control oil chamber PR1 via first passage L1 from discharge pressure introducing passage Lb, which branches off from main gallery MG, and is reduced in pressure through control valve SV, which will be described later. Note that first passage L1 is connected to first control pressure introducing hole 126, which penetrates second housing 12. The first control oil pressure P1 is introduced from first control pressure introducing hole 126 to first control pressure introducing groove 113c, which is provided in flange portion 113 of first housing 11, into first control oil chamber PR1. The hydraulic pressure introduced into the first control oil chamber PR1 acts on a first pressure-receiving surface 441, which is the outer peripheral surface of the cam ring 4 facing the first control oil chamber PR1 and is a first region formed between the swing support portion 42 and the first seal component (first seal member S1). The hydraulic pressure acting on the first pressure-receiving surface 441 applies a moving force (swinging force) to the cam ring 4 in a direction (hereinafter referred to as the "concentric direction") that reduces the eccentricity Δ of the cam ring 4 (the eccentricity Δ of the center O of the pump member accommodating portion 41 relative to the rotation center Z of the drive shaft 2).

[0039] Additionally, a suction-side chamber IH is defined by a first seal member S1 and a second seal member S2 on the outer periphery of the cam ring 4. Oil stored in the oil pan OP is guided into the suction-side chamber IH based on negative pressure generated by the pumping action of the pump member 3. The oil guided into the suction-side chamber IH is then guided to the pump chamber 30 located in the suction region via the first and second suction ports 114, 124 and a suction-side notched groove 461a (described later).

[0040] Here, cam ring 4 has suction-side groove-forming portion 461 in which suction-side notched grooves 461a are formed by cutting out both axial end surfaces facing the suction region. That is, suction-side groove-forming portion 461 is formed thinner than general portion 460 of cam ring 4, and forms communication passages between first housing 11 (bottom wall 111) and second housing 12 that directly communicate each pump chamber 30 located in the suction region with suction-side chamber IH.

[0041] Furthermore, suction-side notched groove 461a opens in the middle of the suction region so as to communicate with suction-side chamber IH, and the opening width on the suction-side chamber IH side is set smaller than the opening width on the pump chamber 30 side. Specifically, suction-side notched groove 461a is formed so that the opening width on the pump chamber 30 side is relatively larger than the opening width of suction-side chamber IH so that both circumferential ends of suction-side notched groove 461a expand from the outer circumferential side to the inner circumferential side of cam ring 4. Note that suction-side notched groove 461a opens so as to communicate with all pump chambers 30 located in the suction region, except for pump chambers 30 corresponding to a pair of confined portions that do not communicate with either first or second suction ports 114, 124 or first or second discharge ports 115, 125.

[0042] Additionally, a spring accommodating chamber SR is defined by a second seal member S2 and a third seal member S3 on the outer circumferential side of the cam ring 4. This spring accommodating chamber SR is disposed opposite the first control oil chamber PR1 across the rotation center Z of the drive shaft 2. A spring accommodating section 116 formed by recessing the inside of the peripheral wall 112 of the pump accommodating section 110 opens into the spring accommodating chamber SR, and a coil spring SP is loaded between this spring accommodating section 116 and the cam ring 4 with a predetermined preload (set load W1).

[0043] Here, spring accommodating portion 116 is formed along a line Y (hereinafter referred to as a "cam ring biasing direction line") that is substantially perpendicular to a line X (hereinafter referred to as a "cam ring center line") that connects the center O of pump member accommodating portion 41, which corresponds to the center of the inner circumference of cam ring 4, and the center of first pin support groove 111b, and that passes through the rotation center Z of drive shaft 2. As shown in FIG. 4, spring accommodating portion 116 is provided between first suction port 114 and first discharge port 115, biased toward first discharge port 115. Specifically, spring accommodating portion 116 is positioned so that a distance De between third seal member S3, which corresponds to the discharge-side seal portion, and a center Cs of coil spring SP is shorter than a distance Di between second seal member S2, which corresponds to the suction-side seal portion, and the center Cs of coil spring SP.

[0044] Furthermore, a spring chamber communication hole 127 that penetrates the second housing 12 is opened in the spring accommodating portion 116. The spring chamber communication hole 127 opens onto the center Cs of the coil spring SP, is open to the atmosphere, and is used to adjust the pressure inside the spring accommodating chamber SR. Note that the spring chamber communication hole 127 is not limited to opening onto the center Cs of the coil spring SP as in this embodiment, and may be provided in a position that does not face the coil spring SP.

[0045] Additionally, a spring abutment portion 440 against which the coil spring SP can abut is provided on the outer side of the cam ring 4. This spring abutment portion 440 is provided opposite the spring accommodating portion 116 and is configured with a flat surface that is approximately parallel to the cam ring center line X. The biasing force of the coil spring SP acts on the spring abutment portion 440, thereby applying a moving force (swinging force) to the cam ring 4 in a direction that increases the eccentricity amount Δ of the cam ring 4 (hereinafter referred to as the "eccentricity direction").

[0046] With the above configuration, when the biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) is smaller than the set load W1 of the coil spring SP, the cam ring 4 moves in the eccentric direction based on the set load W1 of the coil spring SP, reaching the maximum eccentric state as shown in Figure 4. On the other hand, when the discharge pressure P increases and the biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) exceeds the set load W1 of the coil spring SP, the cam ring 4 moves in the concentric direction in response to the discharge pressure P.

[0047] Meanwhile, on the outer circumferential side of cam ring 4, on the opposite side of center O of pump member housing portion 41, there is provided stopper portion 45 that abuts against cam ring abutment portion 112e provided on peripheral wall 112 of pump housing portion 110, thereby restricting movement of cam ring 4 in a direction that increases eccentricity amount Δ of cam ring 4. Stopper portion 45 has stopper abutment surface 450 that is a flat surface that is approximately parallel to spring abutment portion 440, i.e., a flat surface that is approximately perpendicular to the direction in which the biasing force of coil spring SP acts. In other words, when cam ring 4 moves in the eccentric direction, stopper abutment surface 450 of stopper portion 45 abuts against cam ring abutment portion 112e, thereby restricting the maximum eccentricity amount of cam ring 4.

[0048] Furthermore, on the outer circumferential side of cam ring 4, between first seal component 431 (first seal surface 431a) and stopper portion 45 (stopper abutment surface 450), recess 47 is provided by recessing the outer circumferential surface of cam ring 4 radially inward. Recess 47 forms a space between itself and peripheral wall 112 of pump housing portion 110 and functions as an oil collector that collects oil leaking from between first seal member S1 and first seal sliding surface 112a from the first control oil chamber PR1 side. As described above, recess 47 functions as an oil collector that collects oil leaking from first control oil chamber PR1, so it is sufficient that a space can be formed between the outer surface of cam ring 4 and peripheral wall 112 of pump housing portion 110. Therefore, although not specifically shown, the recess 47 may be provided in the peripheral wall 112 of the pump accommodating portion 110 facing the cam ring 4 between the first seal component 431 (first seal surface 431a) and the stopper portion 45 (stopper abutment surface 450).

[0049] As shown in FIGS. 4 and 5 , the stopper portion 45 has a chamfered portion 451 formed on a side edge that faces the pump housing portion 110 in the axial direction, extending over substantially the entire width (longitudinal) direction of the stopper portion 45. The chamfered portion 451 is formed by chamfering a corner of the side edge of the stopper portion 45 in the axial direction at a predetermined angle (e.g., 45 degrees) to form a flat shape, and defines a communication passage CL between the stopper portion 45 and the pump housing portion 110. The communication passage CL connects the recess 47 and the suction-side chamber IH, and guides oil that leaks from the first control oil chamber PR1 into the recess 47 to the suction-side chamber IH via the recess 112f. The chamfered portion 451 also functions as a relief portion to avoid interference with the rounded portion 118 formed at the corner between the bottom wall 111 and the peripheral wall 112 of the pump housing portion 110 during molding of the first housing 11.

[0050] 4, a discharge-side chamber EH is defined on the outer periphery of the cam ring 4 by the pivot pin 40 and the third seal member S3. Discharge port extension 115a faces discharge-side chamber EH, and oil discharged from pump chamber 30 located in the discharge region is guided thereto via first and second discharge ports 115, 125 and a discharge-side notched groove 462a (described later). The oil guided to discharge-side chamber EH is then discharged from discharge port 115b, passes through oil filter F, and is discharged into main gallery MG via discharge passage Le.

[0051] Here, the cam ring 4 has a discharge-side groove-forming portion 462 in which discharge-side notched grooves 462a are formed by cutting out both axial end surfaces facing the discharge region. That is, the discharge-side groove-forming portion 462 is formed thinner than the general portion 460 of the cam ring 4, and forms communication passages between the first housing 11 (bottom wall 111) and the second housing 12, which directly communicate between each pump chamber 30 located in the respective discharge regions and the discharge-side chamber EH.

[0052] Furthermore, the discharge-side notched groove 462a opens at the terminal end of the discharge region to communicate with the discharge-side chamber EH, and the opening width on the discharge-side chamber EH side is set smaller than the opening width on the pump chamber 30 side. Specifically, the opening width of this discharge-side notched groove 462a on the pump chamber 30 side is formed relatively larger than the opening width of the discharge-side chamber EH so that one circumferential end side (the starting end side of the discharge region) of the discharge-side notched groove 462a expands from the outer circumferential side to the inner circumferential side of the cam ring 4. The discharge-side notched groove 462a opens so as to be able to communicate with all of the pump chambers 30 located in the discharge region, except for the pump chambers 30 corresponding to the confined portions that do not communicate with either the first or second suction port 114, 124 or the first or second discharge port 115, 125.

[0053] With the above-described configuration, the variable displacement oil pump VP1 has a series of suction and discharge passages between the first control oil chamber PR1 and the spring accommodating chamber SR, which are fluid-tightly defined relative to the first control oil chamber PR1 and the spring accommodating chamber SR. The suction and discharge passages include the first and second suction ports 114, 124, the suction-side notched groove 461a, the pump chambers 30 facing the suction region and the discharge region, the discharge-side notched groove 462a, and the first and second discharge ports 115, 125. In other words, the suction and discharge passages are formed to penetrate between the first control oil chamber PR1 and the spring accommodating chamber SR without being obstructed by the first control oil chamber PR1 or the spring accommodating chamber SR.

[0054] Furthermore, a relief valve 7 provided adjacent to the discharge port extension 115a in the first housing 11 faces the discharge-side chamber EH. As shown in FIGS. 1 and 4 , the relief valve 7 includes a ball valve element 71 slidably provided in a relief valve hole 117 penetrating the bottom wall 111 of the first housing 11, a valve spring 72 that constantly biases the ball valve element 71 in a valve-closing direction, and a generally annular retainer member 73 on which the valve spring 72 seats. That is, when the pump discharge pressure exceeds the biasing force of the valve spring 72, the ball valve element 71 is displaced by the pump discharge pressure, and the discharge-side chamber EH is connected to the outside (oil pan OP). Consequently, excessively pressurized oil is returned to the oil pan OP, which corresponds to a low-pressure section, via a drain passage Ld. This suppresses malfunctions of the engine, valve timing control device, and other components (not shown) that may be caused by the supply of excessively pressurized oil. The relief valve hole 117 only needs to communicate with a low pressure portion, and may be configured to communicate with the oil pan OP which is at atmospheric pressure, or may be configured to communicate with, for example, the vicinity of the intake port 124a which is at negative pressure.

[0055] (Control valve configuration) 4, in the variable displacement oil pump VP1, the introduction of oil (first control oil pressure P1) into the first control oil chamber PR1 is controlled by a control valve SV, which corresponds to a control mechanism. The control valve SV is a solenoid valve that is driven and controlled by a control unit CU that is responsible for engine control. Specifically, the control valve SV has a valve section 5 that controls the opening and closing of the first passage L1, and a solenoid section 6 that is provided at one end of the valve section 5 and controls the opening and closing of the valve section 5 based on an excitation current output by the control unit CU.

[0056] The valve section 5 is a so-called three-way valve that includes a valve case 51, a spool valve element 52, a retainer member 53, and a valve spring 54. The valve section 5 may be provided integrally with the variable displacement oil pump VP1 by being built into the housing 1, or may be provided separately and independently from the variable displacement oil pump VP1.

[0057] The valve case 51 is made of a predetermined metal material, such as an aluminum alloy, and has a generally cylindrical shape with both ends open in the direction of the central axis Q. The valve case 51 has a valve element accommodating portion 510 therein. The valve element accommodating portion 510 is formed as a stepped through-hole that penetrates the valve case 51 along the direction of the central axis Q of the valve case 51. That is, the valve element accommodating portion 510 has a first valve element sliding contact portion 511 at one end in the direction of the central axis Q, and a second valve element sliding contact portion 512, which has a larger diameter than the first valve element sliding contact portion 511, at the other end in the direction of the central axis Q. The opening of the valve element accommodating portion 510 on the side of the first valve element sliding contact portion 511 is closed by the solenoid unit 6. On the other hand, the opening of the valve element accommodating portion 510 on the side of the second valve element sliding contact portion 512 functions as a drain port Pd that discharges oil from a spring accommodating chamber 55 (described later) and opens to a drain passage Ld. Here, the drain port Pd may not be open to the drain passage Ld but may be directly open to the oil pan OP corresponding to the low-pressure section. Furthermore, the drain port Pd only needs to be connected to the low-pressure section, and may be configured to be connected to the oil pan OP corresponding to atmospheric pressure, or may be configured to be connected to the vicinity of the intake port 124a, which is under negative pressure. In the following description, for convenience, the end of the valve section 5 on the first valve body sliding contact portion 511 side (upper side in FIG. 4) is defined as the first end, and the end on the second valve body sliding contact portion 512 side (lower side in FIG. 4) is defined as the second end.

[0058] A first annular groove 513 is formed on the outer periphery of the first valve body sliding contact portion 511 by cutting out the outer periphery of the valve case 51 in the circumferential direction. A plurality of first valve holes 513a are formed in the bottom of the first annular groove 513, communicating the inside and outside of the valve body accommodating portion 510 in the radial direction of the valve case 51, which is perpendicular to the central axis Q. The first valve holes 513a are formed as round holes that are approximately circular in plan view, and function as introduction ports Pb that introduce oil (discharge pressure P) from the discharge pressure introduction passage Lb.

[0059] Similarly, a second annular groove 514 is formed on the outer circumferential side of the second valve element sliding contact portion 512 by cutting out the outer circumferential surface of the valve case 51 in the circumferential direction. A second valve hole 514a is formed at the bottom of the second annular groove 514, communicating the inside and outside of the valve element accommodating portion 510 in the radial direction of the valve case 51, which is perpendicular to the central axis Q. The second valve hole 514a is formed as a circular hole that is approximately circular in a plan view, and functions as a supply / discharge port Pc for supplying / discharging oil (first control oil pressure P1) to / from the first control oil chamber PR1 through the first passage L1.

[0060] The spool valve element 52 has a stepped cylindrical shape with different outer diameters in the direction of the central axis Q, which is the direction of movement, and is slidably housed in the valve element accommodating portion 510 of the valve case 51. Specifically, the spool valve element 52 has a first land portion 521 that is in sliding contact with the first valve element sliding contact portion 511, and a second land portion 522 that is formed with a larger diameter than the first land portion 521 and is in sliding contact with the second valve element sliding contact portion 512. In addition, an intermediate shaft portion 523 is formed between the first land portion 521 and the second land portion 522 and has a smaller outer diameter than the first land portion 521 and the second land portion 522. In other words, the intermediate shaft portion 523 defines a relay chamber Rc between itself and the valve element accommodating portion 510 in the radial direction of the valve case 51.

[0061] The first land portion 521 and the second land portion 522, which face each other in the direction of the central axis Q in the relay chamber Rc, function as pressure-receiving surfaces that receive the hydraulic pressure introduced from the first valve hole 513a. In this regard, the second land portion 522 has a relatively larger outer diameter than the first land portion 521, and the second pressure-receiving surface Pf2 formed by the second land portion 522 is formed relatively larger than the first pressure-receiving surface Pf1 formed by the first land portion 521. In other words, based on the difference in pressure-receiving area between the first pressure-receiving surface Pf1 and the second pressure-receiving surface Pf2, the hydraulic pressure introduced into the relay chamber Rc from the first valve hole 513a acts on the second pressure-receiving surface Pf2, which is relatively larger than the first pressure-receiving surface Pf1, and presses the spool valve element 52 toward the second end.

[0062] The spool valve element 52 also has a shaft end portion 524, which is located closer to the first end than the first land portion 521 and has a smaller outer diameter than the first land portion 521. The shaft end portion 524 defines a back pressure chamber Rb between the shaft end portion 524 and the valve element accommodating portion 510 in the radial direction of the valve case 51. The back pressure chamber Rb collects oil leaking from the relay chamber Rc through the outer circumferential side of the first land portion 521 (a small gap with the valve element accommodating portion 510). The back pressure chamber Rb communicates with the spring accommodating chamber 55 through a discharge hole 525 formed in a peripheral wall of the first end of the spool valve element 52 facing the back pressure chamber Rb and an internal passage 526 connecting the discharge hole 525 to the spring accommodating chamber 55, which will be described later. That is, the oil collected in the back pressure chamber Rb is guided through the discharge hole 525 and the internal passage 526 to the spring accommodating chamber 55, which will be described later, and is then discharged to the oil pan OP through the drain port Pd and the drain passage Ld.

[0063] The spool valve body 52 also has a spring support portion 527 at its end on the second land portion 522 side facing the retainer member 53, which supports a first end of the valve spring 54 facing the spool valve body 52. ​​The spring support portion 527 is formed by expanding the diameter of the inner circumferential side of the spool valve body 52 in a stepped manner toward the second land portion 522 side, and has a cylindrical spring surrounding portion 527a and a flat spring support surface 527b. As a result, the spring support portion 527 surrounds the outer circumferential side of the first end of the valve spring 54 with the spring surrounding portion 527a, and supports the first end of the valve spring 54 with the spring support surface 527b.

[0064] The retainer member 53 is formed in a generally bottomed cylindrical shape having a cylindrical portion 531 and a bottom wall portion 532 closing the outer end of the cylindrical portion 531. The retainer member 53 is fitted into the open end of the second end of the valve case 51 so that the opening of the cylindrical portion 531 faces the spring support portion 527 of the spool valve body 52. ​​As a result, the retainer member 53 surrounds the outer periphery of the second end of the valve spring 54 with the cylindrical portion 531, and supports the second end of the valve spring 54 with the inner end surface of the bottom wall portion 532. The retainer member 53 also has a circular retainer opening 530 at the center of the bottom wall portion 532. That is, the retainer opening 530 penetrates the bottom wall portion 532 and connects the second valve hole 514a and the drain port Pd.

[0065] The valve spring 54 is a well-known compression coil spring, and is loaded with a predetermined preload (set load W2) into a spring accommodating chamber 55 defined between the spool valve body 52 and the retainer member 53. As a result, the valve spring 54 constantly biases the spool valve body 52 toward the first end side based on the set load W2.

[0066] The solenoid unit 6 includes a cylindrical casing 61, a coil and an armature (not shown) housed inside the casing 61, and a rod 62 fixed to the armature and movable back and forth along the central axis Q together with the armature. An excitation current is applied to the solenoid unit 6 from a control unit CU based on the engine operating state detected or calculated from predetermined parameters such as engine oil temperature, water temperature, and engine speed. The solenoid unit 6 can continuously change the magnitude of the electromagnetic force Fm according to the current value supplied, and is controlled by pulse width modulation (PWM), with the current value being given by a duty ratio Dt.

[0067] (Explanation of oil pump operation) Next, the operation of the variable displacement oil pump VP1 according to this embodiment will be described with reference to FIG.

[0068] That is, in the variable displacement oil pump VP1 according to this embodiment, rotation of a crankshaft (not shown) is transmitted to the drive shaft 2 via a chain (not shown), which in turn drives the rotor 31 to rotate in the rotational direction D. As the rotor 31 rotates, oil is drawn up from the oil pan OP via the intake port 124a, the first and second intake ports 114, 124, and the pair of intake-side notched grooves 461a. Simultaneously with this suction, the oil is discharged into the discharge passage Le via the pair of discharge-side notched grooves 462a, the first and second discharge ports 115, 125, the discharge port extension 115a, and the discharge port 115b. The oil discharged into the discharge passage Le is then pressure-fed via the main gallery MG to the engine's sliding parts (crank metal CM), oil jet device OJ, valve timing control device VT, etc. (not shown), and is also guided to the inlet port Pb of the control valve SV via the discharge pressure introduction passage Lb. In addition, a hydraulic sensor PS capable of detecting the discharge pressure P is disposed in the main gallery MG, and the detection result of this hydraulic sensor PS is fed back to the control device CU.

[0069] Furthermore, as the cam ring 4 swings about the pivot pin 40, the eccentricity Δ, which is the difference between the center of rotation Z of the drive shaft 2 and the center O of the pump member housing portion 41, changes, and the volume change amount (the difference between the maximum volume and the minimum volume) of the pump chamber 30 changes. As the eccentricity Δ increases, the volume change amount of the pump chamber 30 also increases, and as the eccentricity Δ decreases, the volume change amount of the pump chamber 30 also decreases. The eccentricity Δ also changes depending on the concentric biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) and the eccentric biasing force based on the set load W1 of the coil spring SP. In other words, when the concentric biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) is smaller than the eccentric biasing force based on the set load W1 of the coil spring SP, the cam ring 4 swings in the eccentric direction, and the eccentricity Δ increases. On the other hand, when the concentric biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) becomes greater than the eccentric biasing force based on the set load W1 of the coil spring SP, the cam ring 4 swings concentrically, reducing the amount of eccentricity Δ. Then, the cam ring 4 stops at a position where the concentric biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) and the eccentric biasing force based on the set load W1 of the coil spring SP are balanced.

[0070] (Explanation of control valve operation) Fig. 8 is a graph showing the discharge pressure characteristics of variable displacement oil pump VP1. Fig. 9 is a hydraulic circuit diagram showing the operating state of variable displacement oil pump VP1, with (a) showing the state of the pump in section a of Fig. 8 and (b) showing the state of the pump in section b of Fig. 8. Fig. 10 is a hydraulic circuit diagram showing the operating state of variable displacement oil pump VP1, with (a) showing the state of the pump in section c of Fig. 8 and (b) showing the state of the pump in section d of Fig. 8. Fig. 11 is a hydraulic circuit diagram showing the operating state of variable displacement oil pump VP1, with (a) showing the state of the pump in section e of Fig. 8 and (b) showing the state of the pump in section f of Fig. 8.

[0071] P1 in Fig. 8 indicates a first engine-required oil pressure, which corresponds to the oil pressure required by the valve timing control device VT, for example. P2 in Fig. 8 indicates a second engine-required oil pressure, which corresponds to the oil pressure required by the oil jet device OJ that cools the engine pistons, for example. P3 in the figure indicates a third engine-required oil pressure, which is required to lubricate the crankshaft bearing (crank metal CM) at high engine speeds, for example.

[0072] That is, in variable displacement oil pump VP1, in section a from engine start to rotation speed Na, the biasing force Po generated by discharge pressure P acting on the second pressure-receiving surface Pf2 of spool valve element 52 is smaller than the set load W2 of valve spring 54. Therefore, as shown in Figure 9(a), spool valve element 52 is maintained in the position on the first end side, which is the initial position, and supply / discharge port Pc communicates with drain port Pd (first state). As a result, discharge pressure P (first control oil pressure P1) is not introduced into first control oil chamber PR1, and cam ring 4 is maintained in the maximum eccentric state based on the set load W1 of coil spring SP.

[0073] When discharge pressure P eventually reaches first engine required oil pressure P1, to maintain discharge pressure P at first engine required oil pressure P1, the duty ratio Dt of the excitation current supplied to solenoid unit 6 is set to 100%. As a result, electromagnetic force Pm generated in solenoid unit 6, i.e., the pressing force with which rod 62 presses spool valve element 52, becomes greater than set load W2 of valve spring 54. Then, as shown in FIG. 9(b), spool valve element 52 moves toward the second end, communication between supply / discharge port Pc and drain port Pd is blocked, and communication between inlet port Pb and supply / discharge port Pc is established (second state). As a result, in section d of FIG. 8, discharge pressure P (first control oil pressure P1) is introduced into first control oil chamber PR1, and as the discharge pressure P (first control oil pressure P1) introduced into first control oil chamber PR1 increases, the eccentricity Δ of cam ring 4 decreases, and discharge pressure P gradually increases.

[0074] 8, where engine speed N is greater than speed Na but less than speed Nc, the biasing force Po generated by discharge pressure P acting on the second pressure-receiving surface Pf2 of spool valve element 52 is smaller than the set load W2 of valve spring 54, as shown in FIGS. 10(a) and 11(a). Therefore, as shown in FIGS. 10(a) and 11(a), spool valve element 52 is maintained in the initial position, which is the position on the first end side, and supply / discharge port Pc is connected to drain port Pd (first state). As a result, discharge pressure P (first control oil pressure P1) is not introduced into first control oil chamber PR1, and cam ring 4 is maintained in the maximum eccentric state based on the set load W1 of coil spring SP.

[0075] On the other hand, in the range where the engine speed N is lower than the speed Nc, the eccentricity Δ of the cam ring 4 can be controlled by continuously changing the current value (duty ratio Dt) of the excitation current supplied to the solenoid unit 6. Specifically, for example, to maintain the discharge pressure P at the second engine required hydraulic pressure P2, the duty ratio Dt of the excitation current supplied to the solenoid unit 6 is set to 50%. As a result, the resultant force of the hydraulic pressure Po of the discharge pressure P and the electromagnetic force Pm of the solenoid unit 6 becomes greater than the set load W2 of the valve spring 54. Then, as shown in FIG. 10(b), the spool valve element 52 moves toward the second end, blocking communication between the supply / discharge port Pc and the drain port Pd and connecting the inlet port Pb and the supply / discharge port Pc (second state). As a result, in section d of Figure 8, discharge pressure P (first control oil pressure P1) is introduced into the first control oil chamber PR1, and the eccentricity Δ of the cam ring 4 is reduced based on this discharge pressure P (first control oil pressure P1) to reach the minimum eccentricity state, and the discharge pressure P is maintained at the second engine required oil pressure P2.

[0076] In section d, the movement of spool valve element 52 toward the second end due to the increase in discharge pressure P and the movement of spool valve element 52 toward the first end due to the cam ring 4 moving toward the second end and attaining the minimum eccentricity state are alternately and continuously repeated. In this way, the state in which supply / discharge port Pc communicates with introduction port Pb and the state in which supply / discharge port Pc communicates with drain port Pd are alternately and continuously switched, whereby discharge pressure P is maintained at second engine required hydraulic pressure P2.

[0077] When discharge pressure P eventually reaches third engine required oil pressure P3, the hydraulic force Po of discharge pressure P becomes greater than the set load W2 of valve spring 54 with duty ratio Dt of the excitation current supplied to solenoid unit 6 being 0%. As a result, as shown in FIG. 11(b), spool valve element 52 moves toward the second end, blocking communication between supply / discharge port Pc and drain port Pd and connecting inlet port Pb and supply / discharge port Pc. As a result, in section f of FIG. 8, discharge pressure P (first control oil pressure P1) is introduced into first control oil chamber PR1, and the eccentricity Δ of cam ring 4 decreases based on this discharge pressure P (first control oil pressure P1) to reach the minimum eccentricity state, and discharge pressure P is maintained at third engine required oil pressure P3.

[0078] In section f, as in section d, the movement of spool valve element 52 toward the second end due to the increase in discharge pressure P and the movement of spool valve element 52 toward the first end as cam ring 4 reaches the minimum eccentricity state due to the movement of spool valve element 52 toward the second end are alternately and continuously repeated. In this way, the state in which supply / discharge port Pc communicates with introduction port Pb and the state in which supply / discharge port Pc communicates with drain port Pd are alternately and continuously switched, whereby discharge pressure P is maintained at third engine required hydraulic pressure P3.

[0079] (Effects of this embodiment) In the conventional variable displacement oil pump, the arm portion of the cam ring that constitutes the stopper portion is positioned so as to overlap with the intake portion (intake port or intake port) that draws oil into the pump housing. As a result, the arm portion of the cam ring creates intake resistance, reducing the pump's intake performance, and there is room for improvement.

[0080] In contrast, the variable displacement oil pump VP1 according to this embodiment comprises a housing 1 having a pump accommodating portion 110, a cam ring 4 which is an adjustment member movably provided inside the pump accommodating portion 110, and a pump member accommodated inside the cam ring 4, which is rotationally driven by a drive shaft 2 which passes through a rotation center Z which is eccentric with respect to the center of the inner circumference of the cam ring 4 (the center O of the pump member accommodating portion 41), and defines pump chambers 30 which are multiple working chambers between the pump member 3 and the cam ring 4, and as the pump member 3 rotates, oil is sucked into some of the multiple pump chambers 30 through suction portions (first and second suction ports 114, 124 and suction port 124a) which are provided so as to straddle the cam ring 4 in the radial direction relative to the drive shaft 2, and oil is discharged into some of the multiple pump chambers 30 through discharge portions (first and second discharge ports 115, 125, discharge port extension portion 115a and discharge port 115b) which are provided so as to straddle the cam ring 4 in the radial direction. a first control oil chamber PR1 which is a control oil chamber formed between the pump housing portion 110 and the cam ring 4 in the radial direction, and into which oil discharged from the discharge portion (first and second discharge ports 115, 125, discharge port extension portion 115a and discharge port 115b) is guided and which serves to adjust the eccentricity amount Δ of the cam ring 4; and a second control oil chamber PR2 which, by abutting against the cam ring 4, urges the cam ring 4 in a direction in which the eccentricity amount Δ between the center of the inner circumference of the cam ring 4 and the rotation center Z of the drive shaft 2 increases. and a stopper portion 45 provided on cam ring 4, which receives the biasing force (set load W1) of the coil spring SP and abuts against a stopper abutment portion (cam ring abutment portion 112e) provided in pump accommodating portion 110 to restrict movement of cam ring 4 in a direction that increases eccentricity amount Δ, the stopper portion 45 being provided at a position that does not overlap with the suction portion (first and second suction ports 114, 124 and suction port 124a) in the circumferential direction around rotation center Z of drive shaft 4.

[0081] As described above, in the variable displacement oil pump VP1 according to this embodiment, the stopper portion 45 that can come into contact with the cam ring abutment portion 112e provided in the pump housing portion 110 is provided at a position that does not overlap with the first and second suction ports 114, 124 and suction port 124a, which correspond to the suction portions, in the circumferential direction about the rotation center Z of the drive shaft 2. Therefore, there is no risk that the flow of oil that is sucked into the pump chamber 30 in the suction region via the first and second suction ports 114, 124 and suction port 124a, which correspond to the suction portions, will be blocked by the stopper portion 45. As a result, in the variable displacement oil pump VP1, suction resistance during pump operation is reduced, and the suction performance of the pump can be improved.

[0082] Furthermore, in the variable displacement oil pump VP1 according to this embodiment, the control oil chamber is defined by being liquid-tight sealed against the suction portion (first and second suction ports 114, 124 and suction port 124a) via a sealing member (first sealing member S1), and the volume increases when oil discharged from the discharge portion (first and second discharge ports 115, 125, discharge port extension 115a and discharge port 115b) is guided thereto and the eccentricity Δ between the center of the inner circumference of the cam ring 4 (center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2 moves in a direction that decreases, and the stopper portion 45 is provided on the outer periphery of the cam ring 4, between the sealing member (first sealing member S1) and the suction portion (first and second suction ports 114, 124 and suction port 124a).

[0083] As described above, in this embodiment, stopper portion 45 is provided on the outer circumferential side of cam ring 4, between first seal member S1 and first and second suction ports 114, 124 and suction port 124a, which correspond to the suction portion, i.e., between first seal member S1 and suction-side chamber IH. Therefore, stopper portion 45 can be disposed in a position that does not interfere with the suction of oil, thereby improving the suction performance of the pump.

[0084] In addition, in the variable displacement oil pump VP1 according to this embodiment, the stopper portion 45 is positioned close to the seal member (first seal member S1) between the seal member (first seal member S1) and the suction portion (first and second suction ports 114, 124 and suction port 124a).

[0085] As described above, in this embodiment, stopper portion 45 is disposed adjacent to first seal member S1. Therefore, the relatively high-pressure oil introduced into first control oil chamber PR1 flows over first seal member S1 into the relatively low-pressure suction-side chamber IH, and this inflowing oil acts on stopper portion 45 located adjacent to first seal member S1. As a result, the damping effect of the inflowing oil reduces the impact of stopper portion 45 when it abuts against cam ring abutment portion 112e, thereby suppressing noise generation during pump operation.

[0086] Furthermore, in the variable displacement oil pump VP1 according to this embodiment, the coil spring SP abuts against the cam ring 4 and biases the cam ring 4 in a direction that increases the eccentricity Δ between the center of the inner circumference of the cam ring 4 (center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2, and the coil spring SP is disposed in a position in the radial direction between the pump accommodating portion 110 and the cam ring 4, but does not overlap with the suction portion (first and second suction ports 114, 124 and suction port 124a).

[0087] As described above, in this embodiment, the coil spring SP is positioned so as not to overlap with the first and second suction ports 114, 124 and the suction port 124a, which correspond to the suction portion. Therefore, there is no risk that the coil spring SP will block the flow of oil that is drawn into the pump chamber 30 in the suction region through the first and second suction ports 114, 124 and the suction port 124a, which correspond to the suction portion. This further reduces the suction resistance during pump operation, thereby further improving the suction performance of the pump.

[0088] Furthermore, in the variable displacement oil pump VP1 according to this embodiment, the coil spring SP is disposed in a spring accommodating chamber SR, which is a biasing member accommodating chamber formed between the pump accommodating section 110 and the cam ring 4 in the radial direction, and the spring accommodating chamber SR is disposed opposite the first control oil chamber PR1 across the cam ring 4, and is liquid-tight sealed against the suction section (first and second suction ports 114, 124 and suction port 124a) via the second sealing member S2.

[0089] As described above, in this embodiment, the coil spring SP is accommodated in the spring accommodating chamber SR, which is liquid-tightly sealed from the first and second suction ports 114, 124 and suction port 124a, which correspond to the suction portion, i.e., the suction-side chamber IH, between the pump accommodating portion 110 and the cam ring 4. This prevents oil drawn in through the first and second suction ports 114, 124 and suction port 124a, which correspond to the suction portion, from flowing into the spring accommodating chamber SR, and there is no risk of the coil spring SP blocking the flow of oil introduced through the first and second suction ports 114, 124 and suction port 124a. This further smooths the flow of oil near the first and second suction ports 114, 124 and suction port 124a, which are the suction portions, thereby further improving the suction performance of the pump.

[0090] In addition, in the variable displacement oil pump VP1 according to this embodiment, the cam ring 4 swings around a swing fulcrum (pivot pin 40) provided in the pump accommodating section 110 based on the internal pressure (first control oil pressure P1) of the control oil chamber (first control oil chamber PR1) and the biasing force (set load W1) of the coil spring SP.

[0091] In this way, in this embodiment, by making the cam ring 4 a swinging type, the direction in which the internal pressure of the first control oil chamber PR1 (hydraulic pressure Fp1) or the biasing force of the coil spring SP (set load W1) acts coincides with the direction in which the cam ring 4 moves. Therefore, compared to a well-known sliding type in which the discharge pressure acts in a direction perpendicular to the direction in which the cam ring 4 moves, there is no risk of increased frictional resistance or accelerated wear of the first and second seal members S1, S2 that define the suction-side chamber IH. As a result, it is possible to improve the responsiveness of the cam ring 4 and the durability of the pump (device).

[0092] Furthermore, in the variable displacement oil pump VP1 according to this embodiment, the stopper portion 45 is positioned inside an imaginary circle VC drawn along the outermost edge of the intake portion (first and second intake ports 114, 124 and intake port 124a) with the swing fulcrum (pivot pin 40) at its center.

[0093] In this way, in this embodiment, stopper portion 45 is disposed inside the fixed imaginary circle VC, so that stopper portion 45 is not significantly offset toward the outer periphery of cam ring 4, and the pump can be made smaller.

[0094] In addition, in the variable displacement oil pump VP1 of this embodiment, the first control oil chamber PR1 is defined by being liquid-tight sealed against the suction portion (first and second suction ports 114, 124 and suction port 124a) via the first seal member S1, and the cam ring 4 has a first seal component 431 (first seal retaining groove 431b) which is a seal retaining portion for holding the first seal member S1, and a recess 47 which is recessed toward the cam ring 4 side (or the pump accommodating portion 110 side) in the radial direction is provided between the stopper portion 45 in the circumferential direction and the first seal component 431 (first seal retaining groove 431b).

[0095] As described above, in this embodiment, recess 47, which is recessed radially toward cam ring 4, is provided between stopper portion 45 and first seal component 431. As a result, oil is retained in recess 47, and this oil improves the sliding properties of first seal member S1. As a result, good sliding of cam ring 4 can be ensured when restarting the engine after being stopped for a relatively long time.

[0096] In addition, in the variable displacement oil pump VP1 according to this embodiment, oil that is discharged from the discharge section (first and second discharge ports 115, 125, discharge port extension 115a and discharge port 115b) and that has passed through an oil filter F provided in the internal combustion engine is introduced into the first control oil chamber PR1.

[0097] In this manner, in this embodiment, the oil that has passed through the oil filter F is guided to the first control oil chamber PR1. Therefore, oil from which foreign matter has been removed by the oil filter F is guided to the recess 47, which makes it possible to prevent foreign matter from getting caught in the first seal sliding surface 112a or the cam ring abutment portion 112e.

[0098] In addition, in the variable displacement oil pump VP1 according to this embodiment, a communication passage CL is formed between the end edge of the stopper portion 45 in the axial direction and the end edge of the cam ring abutment portion 112e, connecting the recess 47 with the intake portion (first and second intake ports 114, 124 and intake port 124a).

[0099] In this manner, in this embodiment, a communication passage CL that connects recess 47 and suction-side chamber IH is formed between the edge of stopper portion 45 and the edge of cam ring abutment portion 112e. This facilitates oil flow from recess 47 to suction-side chamber IH. As a result, it is possible to prevent foreign matter from becoming caught in first seal sliding surface 112a or cam ring abutment portion 112e, which would otherwise occur if oil in suction-side chamber IH before passing through oil filter F flows into recess 47 via communication passage CL.

[0100] In addition, in the variable displacement oil pump VP1 according to this embodiment, the communicating passage CL is formed between the cam ring 4 and the pump accommodating portion 110 by the chamfered portion 451 that the cam ring 4 has on the side edge of the stopper portion 45 in the axial direction.

[0101] As described above, in this embodiment, the communicating passage CL is formed by the chamfered portion 451 on the side edge of the stopper portion 45. That is, the communicating passage CL can be formed simply by providing the chamfered portion 451 on the side edge of the stopper portion 45. This makes it possible to easily form the communicating passage CL, and suppresses a decrease in the efficiency of pump manufacturing.

[0102] (Variation) 12 to 15 show a modified example of the first embodiment of the variable displacement oil pump according to the present invention. Note that the variable displacement oil pump VP2 according to this modified example is obtained by changing the manner in which the spring accommodating chamber SR according to the first embodiment is used, and other configurations are the same as those of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0103] FIG. 12 is a diagram showing the configuration of a variable displacement oil pump VP2 according to this modified example, and FIGS. 13 to 15 are diagrams used to explain the variable displacement control of the variable displacement oil pump VP2 according to this modified example.

[0104] (Oil pump configuration) 12, the variable displacement oil pump VP2 according to this modification is configured so that oil is introduced into the spring accommodating chamber SR in addition to the first control oil chamber PR1, and the spring accommodating chamber SR also functions as the second control oil chamber PR2. That is, in this variable displacement oil pump VP2, the oscillation of the cam ring 4 is controlled based on the internal pressure of the first control oil chamber PR1, the internal pressure of the second control oil chamber PR2, and the biasing force of the coil spring SP.

[0105] Specifically, the first control oil pressure P1 is introduced into the first control oil chamber PR1 via a first passage L1, one of two passages branched from the discharge pressure introducing passage Lb. The first control oil pressure P1 introduced into the first control oil chamber PR1 is substantially the same as the discharge pressure P introduced to the main gallery MG. The first control oil pressure P1 introduced into the first control oil chamber PR1 acts on a first pressure-receiving surface 441 formed in a first region (first area) between the swing support portion 42 and the first seal component 431 (first seal member S1) on the outer peripheral surface of the cam ring 4 facing the first control oil chamber PR1.

[0106] On the other hand, second control oil pressure P2, which has been reduced in pressure through control valve SV, is introduced into second control oil chamber PR2 via the other second passage L2 branching from discharge pressure introducing passage Lb and spring chamber communication hole 127. The second control oil pressure P2 introduced into second control oil chamber PR2 acts on second pressure-receiving surface 442, which is formed between second seal component 432 (second seal member S2) and third seal component 433 (third seal member S3) (second region) on the outer peripheral surface of cam ring 4 facing second control oil chamber PR2.

[0107] Thus, in the variable displacement oil pump VP2, the oil pressure (first control oil pressure P1) introduced into the first control oil chamber PR1 acts on the first pressure-receiving surface 441, and the oil pressure (second control oil pressure P2) introduced into the second control oil chamber PR2 acts on the second pressure-receiving surface 442, thereby applying a moving force (oscillating force) to the cam ring 4. In other words, in the variable displacement oil pump VP2, the cam ring 4 is controlled to oscillate based on the oil pressure (first control oil pressure P1) in the first control oil chamber PR1, the oil pressure (second control oil pressure P2) in the second control oil chamber PR2, and the biasing force of the coil spring SP.

[0108] In this modification, the areas of first pressure receiving surface 441 and second pressure receiving surface 442 of cam ring 4 are set to be equal. The areas of first pressure receiving surface 441 and second pressure receiving surface 442 can be set arbitrarily. That is, the area of ​​first pressure receiving surface 441 may be set larger than the area of ​​second pressure receiving surface 442, and the area of ​​second pressure receiving surface 442 may be set larger than the area of ​​first pressure receiving surface 441.

[0109] In this modification, spring chamber communication hole 127 for introducing second control oil pressure P2 into second control oil chamber PR2 is biased toward the discharge side and is located opposite coil spring SP. In this manner, spring chamber communication hole 127 is desirably located close to the discharge side, that is, relatively close to supply / discharge port Pc of control valve SV. By locating spring chamber communication hole 127 relatively close to supply / discharge port Pc of control valve SV, the responsiveness of oscillation control of cam ring 4 can be improved.

[0110] With the above-described configuration, in the variable displacement oil pump VP2 according to this modified example, when the biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) is smaller than the resultant force of the biasing force based on the internal pressure of the second control oil chamber PR2 (second control oil pressure P2) and the set load W1 of the coil spring SP, the cam ring 4 is in a maximum eccentric state as shown in Fig. 12. On the other hand, in the variable displacement oil pump VP2, when the discharge pressure P increases and the biasing force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) becomes larger than the resultant force of the biasing force based on the internal pressure of the second control oil chamber PR2 (second control oil pressure P2) and the set load W1 of the coil spring SP, the cam ring 4 moves concentrically in accordance with the discharge pressure P.

[0111] (Control valve configuration) As shown in Fig. 12, in the variable displacement oil pump VP2, the introduction of oil (first control oil pressure P1) into the first control oil chamber PR1 and the introduction of oil (second control oil pressure P2) into the second control oil chamber PR2 are controlled by a control valve SV', which corresponds to a control mechanism. The control valve SV' is a solenoid valve that is driven and controlled by a control unit CU that is responsible for engine control. Specifically, the control valve SV' has a valve section 8 that controls the switching of the second passage L2, and a solenoid section 6 that is provided at one end of the valve section 8 and controls the switching of the valve section 8 based on an excitation current output by the control unit CU.

[0112] The valve portion 8 is a so-called three-way valve that includes a valve case 81, a spool valve element 82, a retainer member 83, and a valve spring 84. The valve portion 8 may be provided integrally with the variable displacement oil pump VP2 by being built into the housing 1, or may be provided separately and independently from the variable displacement oil pump VP2.

[0113] The valve case 81 is made of a predetermined metal material, such as an aluminum alloy, and has a generally cylindrical shape with both ends open in the direction of the central axis Q. The valve case 81 has a valve element accommodating portion 810 therein. The valve element accommodating portion 810 is formed as a stepped through-hole that penetrates the valve case 81 along the direction of the central axis Q of the valve case 81. That is, the valve element accommodating portion 810 has a first valve element sliding contact portion 811 at one end in the direction of the central axis Q, and a second valve element sliding contact portion 812, which has a larger diameter than the first valve element sliding contact portion 811, at the other end in the direction of the central axis Q. The opening of the valve element accommodating portion 810 on the side of the first valve element sliding contact portion 811 is closed by the solenoid unit 6. On the other hand, the opening of the valve element accommodating portion 810 on the side of the second valve element sliding contact portion 812 functions as a drain port Pd that discharges oil from a spring accommodating chamber 85 (described later) and opens to a drain passage Ld. Here, the drain port Pd may not be open to the drain passage Ld but may be directly open to the oil pan OP corresponding to the low-pressure section. Furthermore, the drain port Pd only needs to be connected to the low-pressure section, and may be configured to be connected to the oil pan OP corresponding to atmospheric pressure, or may be configured to be connected to the vicinity of the intake port 124a, which is under negative pressure. In the following description, for convenience, the end of the valve section 8 on the side of the first valve body sliding contact portion 811 (upper side in FIG. 12) is defined as the first end, and the end on the side of the second valve body sliding contact portion 812 (lower side in FIG. 12) is defined as the second end.

[0114] A first annular groove 813 is formed on the outer periphery of the first valve element sliding contact portion 811 by cutting out the outer periphery of the valve case 81 in the circumferential direction. A plurality of first valve holes 813a are formed in the bottom of the first annular groove 813, communicating the inside and outside of the valve element accommodating portion 810 in the radial direction of the valve case 81, which is perpendicular to the central axis Q. The first valve holes 813a are formed as round holes that are roughly circular in plan view, and function as supply / discharge ports Pc for supplying / discharging oil (second control oil pressure P2) to / from the second control oil chamber PR2 through the second passage L2.

[0115] Similarly, a second annular groove 814 is formed on the outer circumferential side of the second valve element sliding contact portion 812 by cutting out the outer circumferential surface of the valve case 81 in the circumferential direction. A plurality of second valve holes 814a are formed in the bottom of the second annular groove 814, communicating the inside and outside of the valve element accommodating portion 810 in the radial direction of the valve case 81, which is perpendicular to the central axis Q. The second valve holes 814a are formed as round holes that are roughly circular in plan view, and function as introduction ports Pb that introduce oil (discharge pressure P) from the discharge pressure introduction passage Lb.

[0116] The spool valve element 82 has a stepped cylindrical shape with different outer diameters in the direction of the central axis Q, which is the direction of movement, and is slidably housed in a valve element housing portion 810 of the valve case 81. Specifically, the spool valve element 82 has a first land portion 821 that slides against the first valve element sliding contact portion 811, and a second land portion 822 that has a larger diameter than the first land portion 821 and slides against the second valve element sliding contact portion 812. An intermediate shaft portion 823 having a smaller outer diameter than the first land portion 821 and the second land portion 822 is formed between the first land portion 821 and the second land portion 822. In other words, the intermediate shaft portion 823 defines a relay chamber Rc between itself and the valve element housing portion 810 in the radial direction of the valve case 81.

[0117] The first land portion 821 and the second land portion 822, which face each other in the direction of the central axis Q in the relay chamber Rc, form a pressure-receiving surface that receives the hydraulic pressure introduced from the second valve hole 814a. Specifically, the second land portion 822 has a relatively larger outer diameter than the first land portion 821, and the second pressure-receiving surface Pf2 formed by the second land portion 822 is formed relatively larger than the first pressure-receiving surface Pf1 formed by the first land portion 821. In other words, based on the difference in pressure-receiving area between the first pressure-receiving surface Pf1 and the second pressure-receiving surface Pf2, the hydraulic pressure introduced into the relay chamber Rc from the second valve hole 814a acts on the second pressure-receiving surface Pf2, which is relatively larger than the first pressure-receiving surface Pf1, and presses the spool valve element 82 toward the second end.

[0118] The spool valve element 82 also has an axial end portion 824, which is located closer to the first end than the first land portion 821 and has a smaller outer diameter than the first land portion 821. The axial end portion 824 defines a backpressure chamber Rb between the axial end portion 824 and the valve element housing portion 810 in the radial direction of the valve case 81. Furthermore, an annular hole 825 is formed by cutting out an annular shape on the outer periphery of the spool valve element 82 between the axial end portion 824 of the spool valve element 82 and the first land portion 821. The annular hole 825 communicates with a spring housing chamber 85 (described later) through an internal passage 826 formed inside the spool valve element 82 and opening toward the second end. As a result, oil in the second control oil chamber PR2 introduced into the backpressure chamber Rb via the first valve hole 813a is introduced through the annular hole 825 and the internal passage 826 to the spring housing chamber 85 (described later) and then discharged into the oil pan OP via a drain port Pd and a drain passage Ld.

[0119] The spool valve body 82 also has a spring support portion 827 at its end on the second land portion 822 side, which faces the retainer member 83, that supports a first end of the valve spring 84 facing the spool valve body 82. The spring support portion 827 is formed by expanding the diameter of the inner circumferential side of the spool valve body 82 in a stepped manner toward the second land portion 822 side, and has a cylindrical spring surrounding portion 827a and a flat spring support surface 827b. As a result, the spring support portion 827 surrounds the outer circumferential side of the first end of the valve spring 84 with the spring surrounding portion 827a, and supports the first end of the valve spring 84 with the spring support surface 827b.

[0120] The retainer member 83 is formed in a generally bottomed cylindrical shape having a cylindrical portion 831 and a bottom wall portion 832 closing the outer end of the cylindrical portion 831. The retainer member 83 is fitted into the open end of the second end of the valve case 81 so that the opening of the cylindrical portion 831 faces the spring support portion 827 of the spool valve body 52. ​​As a result, the retainer member 83 surrounds the outer periphery of the second end of the valve spring 84 with the cylindrical portion 831, and supports the second end of the valve spring 84 with the inner end surface of the bottom wall portion 832. The retainer member 83 also has a circular retainer opening 830 at the center of the bottom wall portion 832. That is, the retainer opening 830 penetrates the bottom wall portion 832 and connects the second valve hole 814a and the drain port Pd.

[0121] The valve spring 84 is a well-known compression coil spring, and is loaded with a predetermined preload (set load W2) into a spring accommodating chamber 85 defined between the spool valve body 82 and the retainer member 83. As a result, the valve spring 84 constantly biases the spool valve body 82 toward the first end side based on the set load W2.

[0122] (Explanation of control valve operation) Fig. 13 is a hydraulic circuit diagram showing the operating state of variable displacement oil pump VP2, with (a) showing the state of the pump in section a of Fig. 8 and (b) showing the state of the pump in section b of Fig. 8. Fig. 14 is a hydraulic circuit diagram showing the operating state of variable displacement oil pump VP2, with (a) showing the state of the pump in section c of Fig. 8 and (b) showing the state of the pump in section d of Fig. 8. Fig. 15 is a hydraulic circuit diagram showing the operating state of variable displacement oil pump VP2, with (a) showing the state of the pump in section e of Fig. 8 and (b) showing the state of the pump in section f of Fig. 8.

[0123] That is, in the variable displacement oil pump VP2, in a section a from engine start to rotation speed Na, the first control oil pressure P1 is introduced into the first control oil chamber PR1 via the first passage L1 branched from the discharge pressure introduction passage Lb. Also, in the control valve SV', the biasing force Po generated by the discharge pressure P acting on the second pressure-receiving surface Pf2 of the spool valve element 82 becomes smaller than the set load W2 of the valve spring 84. Therefore, as shown in FIG. 13(a), the spool valve element 82 is maintained in the position on the first end side, which is the initial position, the introduction port Pb and the supply / discharge port Pc are connected (first state), and the second control oil pressure P2 is introduced into the second control oil chamber PR2. As a result, the resultant force of the hydraulic force Fp2 generated by the second control oil pressure P2 of the second control oil chamber PR2 acting on the second pressure-receiving surface 442 and the set load W1 of the coil spring SP exceeds the hydraulic force Fp1 generated by the first control oil pressure P1 of the first control oil chamber PR1 acting on the first pressure-receiving surface 441, and the cam ring 4 is maintained in the maximum eccentric state.

[0124] When the discharge pressure P eventually reaches the first engine required oil pressure P1, to maintain the discharge pressure P at the first engine required oil pressure P1, the duty ratio Dt of the excitation current supplied to the solenoid unit 6 is set to 100%. As a result, the electromagnetic force Pm generated in the solenoid unit 6, i.e., the pressing force with which the rod 62 presses the spool valve element 82, becomes greater than the set load W2 of the valve spring 84. Therefore, as shown in FIG. 13(b), the spool valve element 82 moves toward the second end, blocking communication between the inlet port Pb and the supply / discharge port Pc and connecting the supply / discharge port Pc and the drain port Pd (second state). As a result, in section b of FIG. 8, the oil in the second control oil chamber PR2 is discharged, and the discharge pressure P acts only on the first control oil chamber PR1. As a result, the hydraulic force Fp1 generated by the discharge pressure P introduced into the first control oil chamber PR1 acting on the first pressure-receiving surface 441 exceeds the set load W1 of the coil spring SP. As a result, the eccentricity Δ of the cam ring 4 decreases as the discharge pressure P increases, and the discharge pressure P increases gradually.

[0125] 8 where the engine speed N is greater than the speed Na but less than the speed Nc, as shown in Figures 14(a) and 15(a), the biasing force Po generated by the oil (discharge pressure P) introduced from the introduction port Pb acting on the second pressure-receiving surface Pf2 of the spool valve element 82 is smaller than the set load W2 of the valve spring 84. Therefore, as shown in Figures 14(a) and 15(a), the spool valve element 82 is maintained in the position on the first end side, which is its initial position, the introduction port Pb and the supply / discharge port Pc are connected (first state), and the second control oil pressure P2 is introduced into the second control oil chamber PR2. As a result, the resultant force of the hydraulic force Fp2 generated by the second control hydraulic pressure P2 introduced into the second control hydraulic chamber PR2 acting on the second pressure-receiving surface 442 and the set load W1 of the coil spring SP exceeds the hydraulic force Fp1 generated by the hydraulic pressure in the first control hydraulic chamber PR1 acting on the first pressure-receiving surface 441, and the cam ring 4 is maintained in the maximum eccentric state.

[0126] On the other hand, in the section where the engine speed N is lower than the speed Nc, the eccentricity Δ of the cam ring 4 can be controlled by continuously varying the current value (duty ratio Dt) of the excitation current supplied to the solenoid unit 6. Specifically, for example, when the discharge pressure P is maintained at the second engine required oil pressure P2, the duty ratio Dt of the excitation current supplied to the solenoid unit 6 is set to approximately 50%. As a result, the resultant force of the hydraulic pressure Po of the discharge pressure P and the electromagnetic force Pm of the solenoid unit 6 becomes greater than the set load W2 of the valve spring 84. Then, as shown in FIG. 14(b), the spool valve element 82 moves toward the second end, blocking communication between the inlet port Pb and the supply / discharge port Pc and connecting the supply / discharge port Pc and the drain port Pd (second state). As a result, in the section d, the oil in the second control oil chamber PR2 is discharged, and the discharge pressure P acts only on the first control oil chamber PR1. As a result, the hydraulic force Fp1 generated by the discharge pressure P (first control hydraulic pressure P1) of the first control hydraulic chamber PR1 acting on the first pressure-receiving surface 441 exceeds the set load W1 of the coil spring SP. As a result, the eccentricity Δ of the cam ring 4 decreases with the increase in discharge pressure P, resulting in a minimum eccentricity state, and the discharge pressure P is maintained at the second engine required hydraulic pressure P2.

[0127] In section d, the movement of spool valve element 82 toward the second end due to the increase in discharge pressure P and the movement of spool valve element 82 toward the first end due to the cam ring 4 moving toward the second end and attaining the minimum eccentricity state are alternately and continuously repeated. In this way, the state in which supply / discharge port Pc communicates with introduction port Pb and the state in which supply / discharge port Pc communicates with drain port Pd are alternately and continuously switched, whereby discharge pressure P is maintained at second engine required hydraulic pressure P2.

[0128] When discharge pressure P eventually reaches third engine required oil pressure P3, the hydraulic force Po of discharge pressure P becomes greater than set load W2 of valve spring 84 while duty ratio Dt of the excitation current supplied to solenoid unit 6 is 0%. Then, as shown in FIG. 15(b), spool valve element 82 moves toward the second end, connecting inlet port Pb and supply / discharge port Pc. As a result, in section f of FIG. 8, oil is discharged from second control oil chamber PR2, and discharge pressure P acts only on first control oil chamber PR1. This causes hydraulic force Fp1, generated by discharge pressure P (first control oil pressure P1) of first control oil chamber PR1 acting on first pressure-receiving surface 441, to exceed set load W1 of coil spring SP. As a result, the eccentricity Δ of cam ring 4 decreases with the increase in discharge pressure P, resulting in a minimum eccentricity state, and discharge pressure P is maintained at third engine required oil pressure P3.

[0129] In section f, as in section d, the movement of spool valve element 82 toward the second end due to the increase in discharge pressure P and the movement of spool valve element 82 toward the first end as cam ring 4 reaches the minimum eccentricity state as a result of the movement of spool valve element 82 toward the second end are alternately and continuously repeated. In this way, the state in which supply / discharge port Pc communicates with introduction port Pb and the state in which supply / discharge port Pc communicates with drain port Pd are alternately and continuously switched over, whereby discharge pressure P is maintained at third engine required hydraulic pressure P3.

[0130] (Effects of this modified example) In the variable displacement oil pump VP2 according to this modification, the control oil chamber includes a first control oil chamber PR1 into which oil discharged from the discharge portion (first and second discharge ports 115, 125, discharge port extension 115a and discharge port 115b) is guided, and whose volume increases when the cam ring 4 moves in a direction in which the eccentricity Δ between the center of the inner circumference of the cam ring 4 (center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2 decreases; 5a and discharge port 115b) is guided into the second control oil chamber PR2, and the volume of the second control oil chamber PR2 increases when the cam ring 4 moves in a direction that increases the eccentricity Δ between the center of the inner circumference of the cam ring 4 (center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2, and when viewed from the axial direction, the abutment surface (stopper abutment surface 450) between the stopper portion 45 and the cam ring abutment portion 112e and the abutment surface (spring abutment portion 440) between the cam ring 4 and the coil spring SP are arranged in parallel.

[0131] As described above, in this modification, when viewed from the axial direction, stopper abutment surface 450, which corresponds to the abutment surface of stopper portion 45 with cam ring abutment portion 112e, and spring abutment portion 440, which corresponds to the abutment surface of cam ring 4 with coil spring SP, are arranged parallel to each other. Therefore, when discharge pressure acts on first control oil chamber PR1 and second control oil chamber PR2 on the outer circumferential side of cam ring 4, annular cam ring 4 is slightly deformed into an elliptical shape so that the radial distance between the first control oil chamber PR1 and the second control oil chamber PR2 decreases. This reduces the tip clearance within pump member accommodating portion 41, i.e., the distance between cam ring 4 and vane 32 in the transition region between the suction region and the discharge region. As a result, it is possible to suppress the inflow of oil from the discharge side (discharge-side chamber EH) to the suction side (suction-side chamber IH) via pump chamber 30 in the transition region, thereby improving the discharge performance of the pump.

[0132] Furthermore, in the variable displacement oil pump VP2 according to this modified example, the pump accommodating portion 110 has a recessed portion 112f that is recessed radially outward between the cam ring abutment portion 112e and the intake portion (first and second intake ports 114, 124 and intake port 124a) when viewed from the axial direction.

[0133] As described above, in this modification, recess 112f recessed radially outward is provided between cam ring abutment portion 112e and suction-side chamber IH in pump accommodating portion 110. Therefore, when cam ring abutment portion 112e is machined during manufacturing of first housing 11, recess 112f makes it possible to secure a clearance for the cutting tool used to machine cam ring abutment portion 112e, thereby facilitating appropriate and satisfactory machining of cam ring abutment portion 112e.

[0134] Furthermore, recess 112f forms a gap between stopper portion 45 and recess 112f. Therefore, when cam ring 4 moves in a direction in which the eccentricity amount Δ decreases, oil flows smoothly into recess 112f, enabling the cam ring 4 to move smoothly.

[0135] [Second embodiment] 16 shows a second embodiment of a variable displacement oil pump according to the present invention. Note that this embodiment is a modification of the first embodiment in that the configurations of stopper portion 45 and cam ring abutment portion 112e are changed, and the other configurations are the same as those of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0136] 16, in variable displacement oil pump VP3 according to this embodiment, stopper portion 45 is provided on the outer side of cam ring 4 adjacent to second seal component 432 on the first seal component 431 side in the circumferential direction, so as to protrude radially outward of cam ring 4. In addition, recessed portion 47 is provided between stopper portion 45 and second seal component 432, recessed radially inward of cam ring 4. Recessed portion 47 functions as an oil collecting portion that collects oil leaked from second control oil chamber PR2.

[0137] Meanwhile, peripheral wall 112 of pump housing portion 110 is provided with recessed portion 112f, which is formed by recessing peripheral wall 112 radially outward, closer to first seal sliding surface 112a than second seal sliding surface 112b. Recessed portion 112f also includes cam ring contact portion 112e, which contacts stopper portion 45 of cam ring 4 to restrict eccentric movement of cam ring 4. Cam ring contact portion 112e is located within a region corresponding to suction-side chamber IH and does not overlap with first suction port 114, second suction port 124, and suction port 124a, which constitute the suction portion according to the present invention. More specifically, in this embodiment, cam ring contact portion 112e is located closer to spring accommodating chamber SR (second control oil chamber PR2) than first suction port 114, second suction port 124, and suction port 124a, which constitute the suction portion, in the circumferential direction. In other words, the cam ring contact portion 112e is provided in the circumferential direction between the first suction port 114, the second suction port 124, and the suction port 124a that constitute the suction portion and the second control oil chamber PR2.

[0138] Similarly to the first embodiment, the cam ring abutment portion 112e has a flat shape that allows it to abut almost entirely against the stopper portion 45 when the cam ring 4 is at its maximum eccentricity, thereby restricting the maximum amount of eccentricity of the cam ring 4. That is, when the cam ring 4 moves in the eccentric direction, the stopper portion 45 abuts against the cam ring abutment portion 112e, thereby restricting the maximum amount of eccentricity of the cam ring 4. Similarly to the first embodiment, the cam ring abutment portion 112e is formed by machining the first, second, and third seal sliding surfaces 112a, 112b, and 112c with a cutting tool such as an end mill that machines the peripheral wall 112 of the pump housing portion 110. In this case, the recessed portion 112f functions as a relief for the cutting tool such as an end mill when machining the peripheral wall 112 of the pump housing portion 110, similar to the first embodiment.

[0139] As described above, in the variable displacement oil pump VP3 according to this embodiment, the control oil chamber comprises a first control oil chamber PR1 into which oil discharged from the discharge portion (first and second discharge ports 115, 125, discharge port extension 115a, and discharge port 115b) is guided, and whose volume increases when the cam ring 4 moves in a direction in which the eccentricity Δ between the center of the inner circumference of the cam ring 4 (center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2 decreases; ) and a second control oil chamber PR2 into which oil discharged from the pump member accommodating portion 41 is guided and whose volume increases when the cam ring 4 moves in a direction that increases the eccentricity Δ between the center of the inner circumference of the cam ring 4 (the center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2, and the suction portion (first and second suction ports 114, 124 and suction port 124a) is provided on the first control oil chamber PR1 side in the circumferential direction, and the stopper portion 45 is provided between the second control oil chamber PR2 and the suction portion (first and second suction ports 114, 124 and suction port 124a).

[0140] As described above, in this embodiment, the stopper portion 45 is disposed circumferentially between the first and second suction ports 114, 124 and suction port 124a, which correspond to the suction portions, and the second control oil chamber PR2. This prevents the stopper portion 45 from interfering with suction, even when the pump layout requires that the first and second suction ports 114, 124 and suction port 124a be located on the first control oil chamber PR1 side. In other words, the layout flexibility of the pump can be improved while preventing the stopper portion 45 from interfering with suction.

[0141] Furthermore, although this embodiment has been described by exemplifying an example in which the spring accommodating chamber SR is configured as the second control oil chamber PR2, which is a modification of the first embodiment, the present invention is not limited to this example. That is, it goes without saying that this embodiment can also be applied to an example in which discharge pressure P is introduced only to the first control oil chamber PR1, as exemplified in the first embodiment. In other words, regardless of whether discharge pressure P is introduced to the spring accommodating chamber SR, the stopper portion 45 is disposed circumferentially between the first and second suction ports 114, 124 and the suction port 124a, which correspond to the suction portion, and the second control oil chamber PR2. As described above, this sufficiently prevents the stopper portion 45 from interfering with the suction of the pump, since the stopper portion 45 is disposed circumferentially between the first and second suction ports 114, 124 and the suction port 124a, which correspond to the suction portion, and the second control oil chamber PR2.

[0142] [Third embodiment] 17 shows a third embodiment of a variable displacement oil pump according to the present invention. Note that this embodiment is a modification of the first embodiment in that the configurations of stopper portion 45 and cam ring abutment portion 112e are changed, and the other configurations are the same as those of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0143] As shown in FIG. 17 , in the variable displacement oil pump VP4 according to this embodiment, a stopper portion 45 is provided on the outer side of the cam ring 4 adjacent to the third seal component 433, protruding radially outward from the cam ring 4. This stopper portion 45 is provided at a position overlapping with the first and second discharge ports 115, 125, the discharge port extension 115a, or the discharge port 115b, which constitute the discharge portion, when viewed from the axial direction. Specifically, the stopper portion 45 is provided at a position where the distance D2 from the stopper portion 45 to the second control oil chamber PR2 is shorter than the distance Dp from the stopper portion 45 to the pivot pin 40, which corresponds to the swing fulcrum. Furthermore, a recessed portion 47 recessed radially inward from the cam ring 4 is provided between the stopper portion 45 and the third seal component 433. The recessed portion 47 functions as an oil collector that collects oil leaked from the second control oil chamber PR2.

[0144] Meanwhile, a cam ring abutment portion 112e that can abut against the stopper portion 45 of the cam ring 4 is formed on the peripheral wall 112 of the pump housing portion 110 between the third seal sliding surface 112c and the discharge port 115b. Similar to the first embodiment, this cam ring abutment portion 112e has a flat shape that can abut against the stopper portion 45 over almost the entire surface when the cam ring 4 is at its maximum eccentricity, thereby restricting the maximum amount of eccentricity of the cam ring 4. In other words, when the cam ring 4 moves in the eccentric direction, the stopper portion 45 abuts against the cam ring abutment portion 112e, thereby restricting the maximum amount of eccentricity of the cam ring 4. Note that, similar to the first embodiment, the cam ring abutment portion 112e is formed by machining the peripheral wall 112 of the pump housing portion 110 together with the first, second, and third seal sliding surfaces 112a, 112b, and 112c using a cutting tool such as an end mill that machines the peripheral wall 112.

[0145] As described above, in the variable displacement oil pump VP4 according to this embodiment, the control oil chamber is made up of the first control oil chamber PR1 into which oil discharged from the discharge portion (first and second discharge ports 115, 125, discharge port extension 115a and discharge port 115b) is introduced and whose volume increases when the cam ring 4 moves in a direction that decreases the eccentricity amount Δ between the center of the inner periphery of the cam ring 4 (center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2; and The stopper portion 45 is provided at a position overlapping with the discharge portion (first and second discharge ports 115, 125, discharge port extension portion 115a and discharge port 115b) when viewed from the axial direction along the drive shaft 2, and is provided at a position where the distance D2 from the stopper portion 45 to the second control oil chamber PR2 is closer to the distance Dp from the stopper portion 45 to the swing fulcrum (pivot pin 40) in the circumferential direction of the rotation center of the drive shaft 2.

[0146] In this manner, in this embodiment, the stopper portion 45 is disposed in the discharge-side chamber EH, so there is no risk that the stopper portion 45 will interfere with the suction of the pump, and the suction resistance during pump operation is reduced, thereby improving the suction performance of the pump.

[0147] Moreover, particularly in the variable displacement oil pump VP4 according to this embodiment, the stopper portion 45 is disposed at a position overlapping the first and second discharge ports 115, 125, the discharge port extension 115a, and the discharge port 115b, which correspond to the discharge portion, when viewed from the axial perspective. Therefore, the stopper portion 45 can change the passage width of the discharge passage formed by the first and second discharge ports 115, 125, the discharge port extension 115a, and the discharge port 115b, which constitute the discharge portion. This can contribute to adjusting the amount of oil discharged through the discharge passage formed by the first and second discharge ports 115, 125, the discharge port extension 115a, and the discharge port 115b.

[0148] Furthermore, although this embodiment has been described by exemplifying an example in which the spring accommodating chamber SR is configured as the second control oil chamber PR2, which is a modification of the first embodiment, the present invention is not limited to this example. That is, it goes without saying that this embodiment can also be applied to an example in which discharge pressure P is introduced only to the first control oil chamber PR1, as exemplified in the first embodiment. In other words, regardless of whether discharge pressure P is introduced to the spring accommodating chamber SR, by disposing the stopper portion 45 in the discharge-side chamber EH, as described above, the problem of the stopper portion 45 interfering with the suction of the pump can be sufficiently suppressed.

[0149] [Fourth embodiment] 18 shows a fourth embodiment of a variable displacement oil pump according to the present invention. Note that this embodiment is obtained by changing the configuration of the swing support portion 42 in the modified example of the first embodiment, and the other configurations are the same as those in the modified example of the first embodiment. Therefore, the same components as those in the modified example of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0150] 18, in the variable displacement oil pump VP5 according to this embodiment, a stopper portion 45 is provided on the outer side of the cam ring 4 adjacent to the third seal component 433 side of the second seal component 432 in the circumferential direction, so as to protrude radially outward of the cam ring 4. In addition, a recessed portion 47 that is recessed radially inward of the cam ring 4 is provided between the stopper portion 45 and the second seal component 432. The recessed portion 47 functions as an oil collecting portion that collects oil leaked from the second control oil chamber PR2.

[0151] Meanwhile, peripheral wall 112 of pump accommodating section 110 is provided with recessed portion 112f, which is formed by recessing peripheral wall 112 radially outward, closer to third seal sliding surface 112c (spring accommodating section 116) than second seal sliding surface 112b. In other words, recessed portion 112f is provided in a region facing spring accommodating chamber SR, which is liquid-tightly sealed from suction-side chamber IH by second seal member S2, i.e., second control oil chamber PR2. Recessed portion 112f is also formed with cam ring abutment portion 112e, which abuts against stopper portion 45 of cam ring 4 to restrict eccentric movement of cam ring 4.

[0152] Similarly to the first embodiment, the cam ring abutment portion 112e has a flat shape that allows it to abut almost entirely against the stopper portion 45 when the cam ring 4 is at its maximum eccentricity, thereby restricting the maximum amount of eccentricity of the cam ring 4. That is, when the cam ring 4 moves in the eccentric direction, the stopper portion 45 abuts against the cam ring abutment portion 112e, thereby restricting the maximum amount of eccentricity of the cam ring 4. Similarly to the first embodiment, the cam ring abutment portion 112e is formed by machining the first, second, and third seal sliding surfaces 112a, 112b, and 112c with a cutting tool such as an end mill that machines the peripheral wall 112 of the pump housing portion 110. In this case, the recessed portion 112f functions as a relief for the cutting tool such as an end mill when machining the peripheral wall 112 of the pump housing portion 110, similar to the first embodiment.

[0153] As described above, in the variable displacement oil pump VP5 according to this embodiment, the control oil chamber comprises a first control oil chamber PR1 into which oil discharged from the discharge portion (first and second discharge ports 115, 125, discharge port extension portion 115a and discharge port 115b) is guided, and whose volume increases when the cam ring 4 moves in a direction in which the eccentricity Δ between the center of the inner circumference of the cam ring 4 (center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2 decreases; The oil discharged from the extension 115a and discharge port 115b is guided through the second control oil chamber PR2, and the volume of the second control oil chamber PR2 increases when the cam ring 4 moves in a direction that increases the eccentricity Δ between the center of the inner circumference of the cam ring 4 (the center O of the pump member accommodating portion 41) and the rotation center Z of the drive shaft 2. The intake portion (first and second intake ports 114, 124 and intake port 124a) is provided on the first control oil chamber PR1 side in the circumferential direction, and the stopper portion 45 is provided inside the second control oil chamber PR2.

[0154] In this manner, in this embodiment, the stopper portion 45 is provided inside the second control oil chamber PR2, which is liquid-tightly sealed with respect to the first and second suction ports 114, 124 and the suction port 124a that constitute the suction portion. This prevents the stopper portion 45 from interfering with suction, thereby improving the suction performance of the pump.

[0155] Furthermore, this embodiment has been described by exemplifying an example in which the spring accommodating chamber SR is configured as the second control oil chamber PR2, which is a modification of the first embodiment, but is not limited to this example. That is, it goes without saying that this embodiment can also be applied to an example in which discharge pressure P is introduced only into the first control oil chamber PR1, as exemplified in the first embodiment. In other words, even in the example in the first embodiment, the second control oil chamber PR2 is fluid-tightly sealed from the suction-side chamber IH as the spring accommodating chamber SR, so there is no risk that the stopper portion 45 disposed inside the spring accommodating chamber SR will interfere with the suction of the pump. This reduces suction resistance during pump operation, improving the suction performance of the pump in this embodiment as well.

[0156] The present invention is not limited to the configurations of the above-described embodiments, and can be freely modified according to, for example, the specifications of the engine and valve timing control device of the vehicle in which the variable displacement oil pumps VP1 to VP5 are mounted.

[0157] Furthermore, in each of the above-described embodiments, a so-called swingable cam ring 4 is used, in which the pump discharge rate is varied by swinging the cam ring 4. However, the means for varying the pump discharge rate is not limited to the swinging motion described above, and it is also possible to vary the pump discharge rate by, for example, linearly moving (sliding) the cam ring 4 in the radial direction. In other words, the manner of movement of the cam ring 4 is not important as long as the pump discharge rate can be varied (the amount of change in the volume of the pump chamber 30 can be varied).

[0158] Furthermore, in each of the above embodiments, the present invention is applied to a vane-type variable displacement oil pump, and therefore the cam ring 4 corresponds to the adjusting member according to the present invention. However, the variable displacement oil pump is not limited to the vane-type, and the present invention can also be applied to other types of variable displacement pumps, for example, a trochoid pump. When the present invention is applied to a trochoid pump, the outer rotor that constitutes the external gear corresponds to the adjusting member.

Claims

1. a housing having a pump housing; an adjustment member movably provided inside the pump accommodating portion; a pump member housed inside the adjusting member, the pump member being rotationally driven by a drive shaft passing through a rotation center eccentric with respect to the center of the inner circumference of the adjusting member, the pump member defining a plurality of working chambers between the pump member and the adjusting member, the pump member sucking oil into some of the working chambers through an intake portion provided so as to straddle the adjusting member in a radial direction relative to the drive shaft as the pump member rotates, and discharging oil from some of the working chambers through a discharge portion provided so as to straddle the adjusting member in the radial direction; a control oil chamber formed between the pump accommodating portion and the adjusting member in the radial direction, into which oil discharged from the discharge portion is guided and which is used to adjust the eccentricity of the adjusting member; a biasing member that biases the adjustment member in a direction that increases the eccentricity between the center of the inner circumference of the adjustment member and the rotation center of the drive shaft by contacting the adjustment member; a stopper portion provided on the adjustment member, which receives the biasing force of the biasing member and comes into contact with a stopper abutment portion provided in the pump accommodating portion to restrict movement of the adjustment member in a direction that increases the eccentricity of the adjustment member, the stopper portion being provided at a position that does not overlap with the suction portion in a circumferential direction around the rotation center of the drive shaft; Equipped with the control oil chamber is defined by being liquid-tightly sealed with respect to the suction portion via a seal member, the adjustment member has a seal holding portion for holding the seal member, a recessed portion recessed toward the adjustment member side or the pump accommodating portion side in the radial direction is provided between the stopper portion and the seal holding portion in the circumferential direction, the biasing member abuts against the adjustment member and biases the adjustment member in a direction that increases an eccentricity between a center of an inner circumference of the adjustment member and a rotation center of the drive shaft, the biasing member is provided in a position between the pump accommodating portion and the adjusting member in the radial direction and not overlapping with the suction portion, a communication passage that communicates the recess and the suction portion is formed between an end edge of the stopper portion and an end edge of the stopper abutment portion in the axial direction along the drive shaft; A variable displacement oil pump.

2. 2. The variable displacement oil pump according to claim 1, the control oil chamber increases in volume when the oil discharged from the discharge portion is guided to the control oil chamber and moves in a direction in which the eccentricity between the center of the inner circumference of the adjustment member and the center of rotation of the drive shaft decreases, The stopper portion is provided between the seal member and the suction portion on the outer circumferential side of the adjustment member. A variable displacement oil pump.

3. 3. The variable displacement oil pump according to claim 2, The stopper portion is disposed between the seal member and the suction portion and at a position close to the seal member. A variable displacement oil pump.

4. 2. The variable displacement oil pump according to claim 1, The control oil chamber is a first control oil chamber into which the oil discharged from the discharge portion is guided, and whose volume increases when the adjustment member moves in a direction that reduces the eccentricity between the center of the inner circumference of the adjustment member and the rotation center of the drive shaft; a second control oil chamber into which the oil discharged from the discharge portion is guided, and whose volume increases when the adjustment member moves in a direction that increases the eccentricity between the center of the inner circumference of the adjustment member and the center of rotation of the drive shaft; Including, the suction portion is provided on the first control oil chamber side in the circumferential direction, The stopper portion is provided inside the second control oil chamber or between the second control oil chamber and the suction portion. A variable displacement oil pump.

5. 2. The variable displacement oil pump according to claim 1, the biasing member is disposed in a biasing member accommodating chamber formed between the pump accommodating portion and the adjusting member in the radial direction, The biasing member accommodating chamber is disposed opposite to the control oil chamber across the adjustment member, and is liquid-tightly sealed against the suction portion via a second seal member. A variable displacement oil pump.

6. 2. The variable displacement oil pump according to claim 1, The adjustment member swings around a swing fulcrum provided in the pump accommodating portion based on the internal pressure of the control oil chamber and the biasing force of the biasing member. A variable displacement oil pump.

7. 7. A variable displacement oil pump according to claim 6, The stopper portion is disposed inside an imaginary circle drawn around the swing fulcrum along the outermost peripheral edge of the suction portion. A variable displacement oil pump.

8. 7. A variable displacement oil pump according to claim 6, The control oil chamber is a first control oil chamber into which the oil discharged from the discharge portion is guided, and whose volume increases when the adjustment member moves in a direction that reduces the eccentricity between the center of the inner circumference of the adjustment member and the rotation center of the drive shaft; a second control oil chamber into which the oil discharged from the discharge portion is guided, and whose volume increases when the adjustment member moves in a direction that increases the eccentricity between the center of an inner circumference of the adjustment member and the center of rotation of the drive shaft; Including, the stopper portion is provided at a position overlapping with the discharge portion when viewed from an axial direction along the drive shaft, and is provided at a position where a distance from the stopper portion to the second control oil chamber is shorter in the circumferential direction than a distance from the stopper portion to the swing fulcrum. A variable displacement oil pump.

9. 2. The variable displacement oil pump according to claim 1, The oil discharged from the discharge portion and passed through an oil filter provided in the internal combustion engine is guided to the control oil chamber. A variable displacement oil pump.

10. 2. The variable displacement oil pump according to claim 1, the communication passage is formed between the adjustment member and the pump accommodating portion by a chamfer that the adjustment member has on a side edge of the stopper portion in the axial direction. A variable displacement oil pump.

11. 2. The variable displacement oil pump according to claim 1, The control oil chamber is a first control oil chamber into which the oil discharged from the discharge portion is guided, and whose volume increases when the adjustment member moves in a direction that reduces the eccentricity between the center of the inner circumference of the adjustment member and the rotation center of the drive shaft; a second control oil chamber into which the oil discharged from the discharge portion is guided, and whose volume increases when the adjustment member moves in a direction that increases the eccentricity between the center of the inner circumference of the adjustment member and the center of rotation of the drive shaft; Including, When viewed from the axial direction along the drive shaft, an abutment surface of the stopper portion with the stopper abutment portion and an abutment surface of the adjustment member with the biasing member are provided in parallel. A variable displacement oil pump.

12. 2. The variable displacement oil pump according to claim 1, When viewed in the axial direction along the drive shaft, the pump accommodating portion has a recessed portion recessed radially outward between the stopper abutment portion and the suction portion. A variable displacement oil pump.

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