Variable displacement pump

Abstract

A variable displacement pump (VP1) according to the present invention is provided with a first recess (471) on a first end surface (FC1) of a cam ring (4), the first recess (471) opening to a first discharge passage (ER1) and having an axial width (D1) increasing from the inside to the outside in the radial direction of the cam ring (4). Therefore, by means of the first recess (471), a sudden change in the flow path cross-sectional area of the first discharge passage (ER1), in particular in the vicinity of the outer peripheral edge of the first end surface (FC1) of the cam ring (4), can be suppressed. This makes it possible to suppress the generation of vortices in the vicinity of the outer peripheral edge of the first end surface (FC1) of the cam ring (4), and to reduce the pressure loss of the pump.

Description

Technical Field

[0001] The present invention relates to variable displacement pumps. Background Art

[0002] As a conventional variable displacement pump, for example, a variable displacement pump described in Patent Document 1 below is known.

[0003] In the variable displacement pump described in Patent Document 1, oil discharged to a discharge port formed in a housing passes axially outside the cam ring and is discharged from a discharge port formed in the housing.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-104968 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] However, in the above-mentioned conventional variable displacement pump, the axially outer end surface of the cam ring is formed substantially parallel to the axially outer end surface of the pump housing portion of the housing. Therefore, when the oil passing through the axially outer end surface of the cam ring flows into the discharge port, a vortex is generated near the outer peripheral edge of the axially outer end surface of the cam ring, resulting in pressure loss. Therefore, there is room for improvement in this regard.

[0009] Therefore, the present invention has been made in view of the above-mentioned technical problems of the conventional variable displacement pump, and an object of the present invention is to provide a variable displacement pump capable of reducing the pressure loss of the pump.

[0010] Technical solutions for solving technical problems

[0011] As one aspect thereof, the present invention provides a recessed portion on a first end surface, which is one axial end surface of the cam ring. The recessed portion opens to the discharge passage and has an axial width that increases from the radial inside to the radial outside of the cam ring.

[0012] Effects of the Invention

[0013] According to the present invention, the pressure loss of the pump can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an exploded perspective view of the variable displacement pump according to the first embodiment of the present invention.

[0015] Figure 2 It means that Figure 1 A plan view of a variable displacement pump with a second housing removed.

[0016] Figure 3yes Figure 2 An enlarged view of the main part.

[0017] Figure 4 yes Figure 3 A-A line cross-sectional view.

[0018] Figure 5 This is a graph showing the discharge oil pressure characteristics of the variable displacement pump of the present invention.

[0019] Figure 6 is a hydraulic circuit diagram showing the operating state of the variable displacement pump according to the first embodiment of the present invention, (a) is a diagram showing Figure 5 The state of the pump in interval a is shown in Figure 1, and (b) is the state of the pump in interval a. Figure 5 Graph of the pump status in interval b.

[0020] Figure 7 is a hydraulic circuit diagram showing the operating state of the variable displacement pump according to the first embodiment of the present invention, (a) is a diagram showing Figure 5 The state of the pump in the interval c is shown in Figure 2, (b) is a diagram showing Figure 5 Diagram of the state of the pump in the interval d.

[0021] Figure 8 is a hydraulic circuit diagram showing the operating state of the variable displacement pump according to the first embodiment of the present invention, (a) is a diagram showing Figure 5 The state of the pump in the interval e is shown in Figure 1, and (b) is a diagram showing Figure 5 Diagram of the state of the pump in the interval f.

[0022] Fig. 9 (a) is a CFD analysis diagram of the variable displacement pump according to the first embodiment of the present invention, and (b) is a CFD analysis diagram of a conventional variable displacement pump.

[0023] Fig.10 This is a graph comparing the pressure loss of the variable displacement pumps according to the first and second embodiments of the present invention and a conventional variable displacement pump.

[0024] Fig.11 The first inclined surface is expressed in terms of angle Figure 3 An enlarged view of the main part.

[0025] Fig.12 This is a graph showing the pressure loss of the variable displacement pump according to the angle of the first inclined surface.

[0026] Fig.13 It is a plan view showing a state where the second casing of the variable displacement pump according to the second embodiment of the present invention is removed.

[0027] Fig.14 yes Fig.13 BB line cross-sectional view.

[0028] Fig.15 It is an enlarged view of a main part of a variable displacement pump according to a third embodiment of the present invention.

[0029] Fig.16 It is a plan view showing a state where the second casing of a variable displacement pump according to a fourth embodiment of the present invention is removed.

[0030] Fig.17 yes Fig.16 C-C line cross-sectional view.

[0031] Fig.18 is a diagram showing a modified example of the fourth embodiment of the present invention, which is equivalent to Fig.16 Figure 2 is a cross-section of the C-C line. DETAILED DESCRIPTION

[0032] Hereinafter, the embodiment of the variable capacity pump of the present invention will be described in detail based on the accompanying drawings. It should be noted that in the following embodiments, an example of using the variable capacity pump as a pump for supplying lubricating oil of an internal combustion engine to a valve timing control device is shown, and the valve timing control device is used for the sliding part of an internal combustion engine for an automobile and the opening and closing timing control of the valve of the internal combustion engine. In addition, in the following description, for convenience, the direction along the rotation axis of the drive shaft 2 is defined as "axial", the direction orthogonal to the rotation axis of the drive shaft 2 is defined as "radial", and the rotation direction of the drive shaft 2 is defined as "circumferential" for description.

[0033] [First embodiment]

[0034] Figures 1 to 12 A variable displacement pump VP1 according to a first embodiment of the present invention is shown.

[0035] (Structure of variable capacity pump)

[0036] Figure 1 An exploded perspective view showing a variable displacement pump VP1 according to a first embodiment of the present invention. Figure 2 It means in Figure 1 The variable displacement pump VP1 shown is a plan view of the variable displacement pump VP1 in a state where the second housing is removed.

[0037] like Figure 1 , Figure 2As shown, the variable displacement pump VP1 includes: a drive shaft 2; a pump assembly 3, which is driven to rotate by the drive shaft 2; a cam ring 4, which is provided on the outer peripheral side of the pump assembly 3 in a swingable manner; and a coil spring SP, which is equivalent to a biasing member that biases the cam ring 4 in an eccentric direction; and they are accommodated in the housing 1. It should be noted that in this embodiment, the variable displacement pump VP1 is fastened to the side of the engine (cylinder block) (not shown) by bolts (not shown).

[0038] like Figure 1 As shown, the housing 1 comprises: a cup-shaped first housing 11, which is equivalent to a pump body; and a cover-shaped second housing 12, which is joined to the first housing 11 and is equivalent to a cover member for closing the opening of the first housing 11. It should be noted that the first housing 11 and the second housing 12 are integrally formed of a metal material, such as an aluminum alloy.

[0039] 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 in the circumferential direction along the outer peripheral edge of the bottom wall 111. That is, the first housing 11 has an open end side in the axial direction opposite to the second housing 12, and the other end side is closed by the bottom wall 111. In other words, the cup-shaped pump housing portion 110 is defined inside the first housing 11 by the bottom wall 111 and the peripheral wall 112.

[0040] In addition, a flange portion 113 constituting a joint surface with the second housing 12 is provided at an opening edge portion at one axial end side of the first housing 11. The flange portion 113 is provided along the circumferential direction of the first housing 11 and is formed integrally with the peripheral wall 112. In addition, the flange portion 113 has a plurality of internal threaded holes 113a. The plurality of internal threaded holes 113a are provided at intervals in the circumferential direction, and a screw (not shown) for fastening the second housing 12 to the first housing 11 is screwed into each internal threaded hole 113a.

[0041] In addition, a first bearing hole (not shown) for rotatably supporting one end of the drive shaft 2 is penetrated at a substantially central position of the bottom wall 111 constituting one end wall of the pump housing 110. In addition, a first pin support groove 111b for swingably supporting the cam ring 4 via a cylindrical pivot pin 40 is formed on the inner side surface of the bottom wall 111.

[0042] In addition, if Figure 2 As shown, on the inner side surface of the peripheral wall 112, relative to the straight line M connecting the center Z of the first bearing hole (not shown) and the center Q of the first pin support groove 111b (hereinafter referred to as the "cam ring reference line"), Figure 2A first sealing sliding contact surface 112a is formed on the upper side of the cam ring 4 with which the first sealing component S1 on the outer peripheral side of the cam ring 4 slides. The first sealing sliding contact surface 112a is formed into an arc surface having a curvature formed by a first radius R1 from the center Q of the first pin support groove 111b. It should be noted that the first sealing sliding contact surface 112a is set to a circumferential length that the first sealing component S1 can slide in contact with within the swing range of the cam ring 4.

[0043] Similarly, relative to the cam ring reference line M, Figure 5 The second sealing sliding contact surface 112b and the third sealing sliding contact surface 112c are formed on the lower side of the cam ring 4 for sliding contact with the second sealing component S2 and the third sealing component S3 provided on the outer peripheral side of the cam ring 4. The second sealing sliding contact surface 112b is formed into an arc surface having a curvature formed by the second radius R2 from the center Q of the first pin support groove 111b, and the third sealing sliding contact surface 112c is formed into an arc surface having a curvature formed by the third radius R3 from the center Q of the first pin support groove 111b. It should be noted that the second sealing sliding contact surface 112b is set to a circumferential length that the second sealing component S2 can slide in contact with within the swing range of the cam ring 4, and the third sealing sliding contact surface 112c is set to a circumferential length that the third sealing component S3 can slide in contact with within the swing range of the cam ring 4.

[0044] In addition, on the inner side surface of the bottom wall 111, a first suction portion 114 is formed on the outer peripheral side of the first bearing hole (not shown) to open to a region where the volume of the pump chamber 30 is expanded (hereinafter referred to as the "suction region") to be described later and to guide the oil to the pump chamber 30 along with the pump action of the pump assembly 3. On the other hand, on the side opposite to the suction region across the rotation center Z of the drive shaft 2, a first discharge portion 115 is formed to open to a region where the volume of the pump chamber 30 is reduced (hereinafter referred to as the "discharge region") to be described later and to discharge the oil in the pump chamber 30 along with the pump action of the pump assembly 3.

[0045] The first suction portion 114 includes a first suction port 114a that is substantially arc-shaped along the rotation direction D of the drive shaft 2, a first suction port extension 114b that extends radially outward from the middle position of the first suction port 114a, and a substantially circular suction port 114c that is provided at the front end of the first suction port extension 114b. Here, the suction port 114c may be directly opened to the oil pan OP via a filter not shown, or may be connected to the oil pan OP via a suction passage not shown. Furthermore, at the first suction port 114a, oil as a working fluid stored in the oil pan OP attached to the engine (not shown) is introduced into the interior of the pump housing 110 via the suction port 114c. In this way, in the variable displacement pump VP1, the oil stored in the oil pan OP is sucked into each pump chamber 30 of the suction region via the first suction portion 114 and the second suction portion 124 described later by the negative pressure generated by the pump action of the pump assembly 3. In this way, the suction portion of the present invention is constituted by the first suction portion 114 and the second suction portion (not shown) described later.

[0046] The first discharge portion 115 has a first discharge port 115a which is substantially arc-shaped along the rotation direction D of the drive shaft 2, a first discharge port extension 115b which extends radially outward from the middle position of the first discharge port 115a, and a discharge port 115c which is provided at the front end side of the first discharge port extension 115b and opens to the outside in a manner penetrating the peripheral wall 112. That is, in the variable displacement pump VP1, the oil pressurized by the pump action of the pump assembly 3 is discharged to the outside through the first discharge portion 115 and the second discharge portion 125 described later, and is supplied to the sliding parts of the engine (not shown) such as the crank metal CM, the oil injection device (not shown) for cooling the piston of the engine (not shown), and the valve timing control device VT (not shown) through the main oil gallery MG provided inside the cylinder body (not shown). In this way, the discharge portion of the present invention is constituted by the first discharge portion 115 and the second discharge portion 125 described later.

[0047] like Figure 1 As shown, the second housing 12 functions as a cover member in the shape of a lid that closes the opening of 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 not shown. Specifically, the second housing 12 has a plurality of screw through holes 121a at positions corresponding to the internal threaded holes 113a of the first housing 11. That is, the second housing 12 is fastened to the first housing 11 by screwing the unillustrated screws that penetrate the plurality of screw through holes 121a into the respective internal threaded holes 113a of the first housing 11. It should be noted that the second housing 12 is fastened by the unillustrated screws in a state where the second housing 12 is positioned relative to the first housing 11 by the positioning pins LP.

[0048] In addition, the second housing 12 has a second bearing hole 122a formed therethrough at a position opposite to the first bearing hole 111a of the first housing 11, which supports the other end side of the drive shaft 2 so that it can rotate. In addition, on the inner side surface of the second housing 12, a second pin support groove (not shown), a second suction port (not shown) constituting a second suction portion (not shown) and a second suction port extension (not shown), and a second discharge port 125a constituting a second discharge portion 125 (see Figure 4 ) and the second outlet extension 125b (refer to Figure 4 ) are also respectively arranged opposite to the first pin support groove 111b, the first suction port 114a, the first suction port extension 114b, the first discharge port 115a and the first discharge port extension 115b.

[0049] like Figure 1 , Figure 2 As shown, a general drive shaft portion 21 of the drive shaft 2 formed on one end side in the axial direction is rotatably supported in a first bearing hole (not shown) of the first housing 11. On the other hand, in the drive shaft 2, a large-diameter drive shaft portion 22 having an outer diameter larger than the general drive shaft portion 21 on the other end side in the axial direction is rotatably supported in a second bearing hole 122a of the second housing 12. In addition, a drive shaft end portion 23 of the drive shaft 2 formed with a relatively small diameter at the other end side than the large-diameter drive shaft portion 22 faces outward through the second bearing hole 122a, and is connected to a crankshaft of an unillustrated engine via a transmission component such as a chain that is not shown in the figure. That is, the drive shaft 2 causes the pump assembly 3 to rotate based on the rotational force transmitted from the unillustrated crankshaft. Figure 2 The direction of rotation D rotates. Here, Figure 2 The straight line N (hereinafter referred to as “cam ring eccentric direction line”) passing through the rotation center Z of the drive shaft 2 and being orthogonal to the cam ring reference line M is the boundary between the suction region and the discharge region.

[0050] like Figure 1 , Figure 2 As shown, the pump assembly 3 is accommodated on the inner circumference side of the cam ring 4, and includes: a rotor 31, which is driven to rotate by the drive shaft 2; and a plurality of blades 32, which are accommodated in a plurality of slits 312 cut radially on the outer circumference side of the rotor 31 in a manner that they can appear and disappear. In addition, a pair of ring members 33, 33 formed with a smaller diameter than the rotor 31 and accommodated on the inner side of each blade 32 in the radial direction are arranged at both ends of the rotor 31 in the axial direction.

[0051] For the rotor 31, if Figure 1 , Figure 2As shown in FIG. 1 , a shaft through hole 311 is axially penetrated in the center portion, and a plurality of slits 312 are radially cut out from the center side of the shaft through hole 311 to the radial outside. In addition, a back pressure chamber 313 having a substantially circular cross-section for introducing oil is provided at the bottom of each slit 312. That is, each vane 32 is configured so as to be pushed outward (toward the cam ring 4) by the centrifugal force generated by the rotation of the rotor 31 and the pressure of the oil introduced into the back pressure chamber 313.

[0052] In addition, the plurality of blades 32 accommodated in the rotor 31 are formed into a rectangular plate shape from a predetermined metal material, and each of the front end surfaces slides in contact with the inner peripheral surface of the cam ring 4 as the rotor 31 rotates. That is, the top end surface of each blade 32 slides in contact with the inner peripheral surface of the cam ring 4, so that the rotor 31, a pair of blades 32, 32 adjacent in the circumferential direction, and the cam ring 4 define a plurality of pump chambers 30 in the rotation direction D of the rotor 31. In addition, each blade 32 is configured so that, as the rotor 31 rotates, its base end surface slides in contact with the outer peripheral surface of a pair of ring members 33, 33, and is pushed outward in the radial direction of the rotor 31 by the pair of ring members 33, 33. Thus, even when the internal combustion engine speed is low and the centrifugal force and oil pressure in the back pressure chamber 313 caused by the rotation of the rotor 31 are small, the top end surface of each blade 32 slides in contact with the inner peripheral surface of the cam ring 4, thereby liquid-tightly partitioning each pump chamber 30.

[0053] like Figure 1 , Figure 2 As shown, the cam ring 4 is formed of a sintered material into a substantially annular shape, and has a circular pump assembly housing portion 41 capable of housing the pump assembly 3 on the inner circumference. In addition, a swing support portion 42 in the shape of an arc groove is provided on the outer circumference of the cam ring 4 along the axial direction, which can slide in contact with the outer circumference of the cylindrical pivot pin 40 supported by the housing 1. That is, the cam ring 4 is supported in a swingable manner inside the pump housing portion 110 via the pivot pin 40 by sliding in contact with the outer circumference of the pivot pin 40 supported by the first pin support groove 111b and the second pin support groove 122b. In addition, the swing support portion 42 is pressed against the pivot pin 40 by the discharge pressure P acting on the inner side surface of the cam ring 4 (pump assembly housing portion 41) in the discharge area accompanying the pump action of the pump assembly 3.

[0054] In addition, the cam ring 4 has a first sealing structure 431, a second sealing structure 432, and a third sealing structure 433 on the outer peripheral side thereof, which are respectively opposed to the first sealing sliding contact surface 112a, the second sealing sliding contact surface 112b, and the third sealing sliding contact surface 112c of the first housing 11. The first sealing structure 431 has a first sealing surface 431a which is concentric with the first sealing sliding contact surface 112a. The second sealing structure 432 has a second sealing surface 432a which is concentric with the second sealing sliding contact surface 112b. The third sealing structure 433 has a third sealing surface 433a which is concentric with the third sealing sliding contact surface 112c.

[0055] In addition, a first seal retaining groove 431b extending in the axial direction is formed on the first seal surface 431a so as to open toward the first seal sliding contact surface 112a. A second seal retaining groove 432b extending in the axial direction is formed on the second seal surface 432a so as to open toward the second seal sliding contact surface 112b. A third seal retaining groove 433b extending in the axial direction is formed on the third seal surface 433a so as to open toward the third seal sliding contact surface 112c.

[0056] Furthermore, the first seal holding groove 431b contains a first seal member S1 that comes into sliding contact with the first seal sliding contact surface 112a when the cam ring 4 swings. The second seal holding groove 432b contains a second seal member S2 that comes into sliding contact with the second seal sliding contact surface 112b when the cam ring 4 swings. The third seal holding groove 433b contains a third seal member S3 that comes into sliding contact with the third seal sliding contact surface 112c when the cam ring 4 swings.

[0057] like Figure 1 , Figure 2 As shown, the first sealing member S1, the second sealing member S2 and the third sealing member S3 are all formed of a low-friction material such as a fluorine resin material and are linearly elongated along the axial direction of the cam ring 4. Figure 2 As shown in the figure, a rubber elastic member BR is disposed at each bottom of the first seal holding groove 431b, the second seal holding groove 432b, and the third seal holding groove 433b. That is, the first, second, and third seal members S1, S2, and S3 elastically contact the first, second, and third seal sliding contact surfaces 112a, 112b, and 112c, respectively, by the elastic force of the elastic member BR, thereby sealing the first, second, and third seal surfaces 431a, 432a, and 433a with the first, second, and third seal sliding contact surfaces 112a, 112b, and 112c in a liquid-tight manner.

[0058] In addition, according to this structure, on the outer peripheral side of the cam ring 4, as shown in FIG. Figure 2As shown, the first control oil chamber PR1 is defined by the swing support portion 42 supported by the pivot pin 40 and the first sealing member S1. In the first control oil chamber PR1, the first control oil pressure P1 is introduced through the first passage L1, one of which is branched in two from the discharge pressure introduction passage Lb connected to the main oil gallery MG. It should be noted that the first control oil pressure P1 introduced into the first control oil chamber PR1 is substantially the same as the discharge pressure P introduced into the main oil gallery MG. In addition, the first passage L1 is connected to the first control pressure introduction hole 118 penetrating the bottom wall 111 of the first housing 11, and the first control oil pressure P1 is directly introduced into the first control oil chamber PR1 through the first control pressure introduction hole 118. The first control oil pressure P1 introduced into the first control oil chamber PR1 acts on the outer peripheral surface of the cam ring 4 facing the first control oil chamber PR1 and is formed on the first pressure receiving surface 441 between the swing support portion 42 and the first sealing member S1. That is, through the oil pressure acting on the first pressure-bearing surface 441, a moving force (swinging force) is applied to the cam ring 4 in a direction (hereinafter referred to as the "concentric direction") in which the eccentricity Δ of the cam ring 4 (the eccentricity of the center O of the pump assembly housing 41 relative to the rotation center Z of the drive shaft 2) is reduced.

[0059] Similarly, on the outer peripheral side of the cam ring 4, on the side opposite to the first control oil chamber PR1 across the rotation center Z of the drive shaft 2, a second control oil chamber PR2 is defined by the second seal member S2 and the third seal member S3. In the second control oil chamber PR2, the second control oil pressure P2 reduced in pressure via the control valve SV is introduced from the other second passage L2 branched from the discharge pressure introduction passage Lb. In addition, the second passage L2 introduces the second control oil pressure P2 into the second control oil chamber PR2 via the second control pressure introduction hole 119 penetrating the bottom wall 111 of the first housing 11. The second control oil pressure P2 introduced into the second control oil chamber PR2 acts on the outer peripheral surface of the cam ring 4 facing the second control oil chamber PR2 and formed between the second seal member S2 and the third seal member S3. That is, by the oil pressure acting on the second pressure receiving surface 442, a moving force (swing force) is applied to the cam ring 4 in the direction in which the eccentricity Δ of the cam ring 4 increases (hereinafter referred to as the "eccentricity direction") .

[0060] Here, a spring housing portion 116 for housing a coil spring SP is formed on the peripheral wall 112 of the first housing 11 facing the second control oil chamber PR2. The spring housing portion 116 is formed in a substantially rectangular concave shape, and the coil spring SP is loaded with a predetermined preload (set load W1) between the spring housing portion 116 and the arm portion 45 of the cam ring 4. The coil spring SP always applies force to the cam ring 4 in the eccentric direction based on the set load W1.

[0061] According to the above structure, when the force of the variable displacement pump VP1 based on the internal pressure of the first control oil chamber PR1 (the first control oil pressure P1) is smaller than the combined force of the force based on the internal pressure of the second control oil chamber PR2 (the second control oil pressure P2) and the set load W1 of the coil spring SP, the cam ring 4 becomes Figure 2 On the other hand, when the discharge pressure P rises and the force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) becomes larger than the combined force of the 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 in the concentric direction according to the discharge pressure P.

[0062] Here, an arm portion 45 for receiving the force (set load W1) of the coil spring SP is provided on the outer peripheral side of the cam ring 4, on the opposite side of the rotation center Z of the drive shaft 2. The arm portion 45 is provided so as to extend substantially linearly toward the outer peripheral side of the cam ring 4, and constitutes the point of action of the force (set load W1) of the coil spring SP.

[0063] In addition, a stopper 46 for limiting the movement of the cam ring 4 in the eccentric direction is provided on the outer peripheral side of the cam ring 4. The stopper 46 limits the maximum eccentricity of the cam ring 4 by abutting against the cam ring abutment 117 provided on the peripheral wall 112 of the first housing 11. It should be noted that the stopper 46 may be provided integrally with the arm 45 in addition to being provided separately from the arm 45 as in the present embodiment. In this case, the surface of the arm 45 on the side opposite to the spring abutment surface 451 is used as a stopper surface 452, and by making the stopper surface 452 abut against the cam ring abutment 117, the maximum eccentricity of the cam ring 4 can be limited.

[0064] (Control valve structure)

[0065] In addition, if Figure 2 As shown, the variable displacement pump VP1 controls the introduction of oil (second control oil pressure P2) to the first control oil chamber PR1 through the control valve SV. The control valve SV is an electromagnetic valve driven and controlled by the control unit CU responsible for engine control. Specifically, the control valve SV has a valve portion 5 for opening and closing control of the second passage L2, and a solenoid portion 6 provided at one end of the valve portion 5 and used for opening and closing control of the valve portion 5 based on the excitation current output by the control unit CU.

[0066] The valve portion 5 is a so-called three-way valve including a valve housing 51, a spool valve element 52, a retaining member 53, and a valve spring 54. It should be noted that the valve portion 5 may be provided integrally with the variable displacement pump VP1 in the form of being built into the housing 1, or may be provided separately from the variable displacement pump VP1.

[0067] The valve housing 51 is made of a predetermined metal material, such as an aluminum alloy material, and is in a generally cylindrical shape with both ends opened in the direction of the central axis Y, and has a valve core housing portion 510 inside. The valve core housing portion 510 is composed of a stepped through hole that penetrates the valve housing 51 along the direction of the central axis Y of the valve housing 51. That is, the valve core housing portion 510 has a first valve core sliding contact portion 511 on one end side in the direction of the central axis Y, and a second valve core sliding contact portion 512 with a larger diameter than the first valve core sliding contact portion 511 on the other end side in the direction of the central axis Y. Moreover, the opening portion of the valve core housing portion 510 on the side of the first valve core sliding contact portion 511 is blocked by the solenoid portion 6. On the other hand, the opening portion of the valve core housing portion 510 on the side of the second valve core sliding contact portion 512 functions as a drain port Pd for discharging oil from the spring housing chamber 55 described later, and opens to the drain passage Ld. Here, the discharge port Pd may not open to the discharge passage Ld, but may directly open to the oil pan OP corresponding to the low pressure part. In addition, the discharge port Pd only needs to be connected to the low pressure part, and in addition to the structure of connecting to the oil pan OP corresponding to the atmospheric pressure, it may also be configured to be connected to the vicinity of the suction port 114c where the negative pressure is formed. It should be noted that, in the following, for the sake of convenience, the first valve core sliding contact part 511 side ( Figure 2 The end portion on the right side of the second valve core sliding contact portion 512 ( Figure 2 The end portion (on the left side in FIG. 1 ) is defined as the second end portion for explanation.

[0068] A first annular groove 513 formed by cutting the outer peripheral surface of the valve housing 51 in the circumferential direction is formed on the outer peripheral side of the first valve core sliding contact portion 511. In addition, a plurality of first valve holes 513a are formed at the bottom of the first annular groove 513 to communicate the inside and outside of the valve core housing portion 510 in the radial direction of the valve housing 51 orthogonal to the central axis Y. The first valve hole 513a is composed of a circular hole that is substantially circular in a plan view, and functions as a supply and discharge port Pc for supplying and discharging oil (first control oil pressure P2) with respect to the second control oil chamber PR2 through the second passage L2.

[0069] In addition, similarly, a second annular groove 514 is formed by cutting the outer peripheral surface of the valve housing 51 in the circumferential direction on the outer peripheral side of the second valve core sliding contact portion 512. In addition, a second valve hole 514a is formed at the bottom of the second annular groove 514 to communicate the inside and outside of the valve core housing 510 in the radial direction of the valve housing 51 orthogonal to the central axis Y. It should be noted that the second valve hole 514a is composed of a circular hole that is substantially circular in a plan view, and functions as an introduction port Pb for introducing oil (discharge pressure P) from the discharge pressure introduction passage Lb.

[0070] The spool valve core 52 is a cylindrical shape formed in a stepped shape with different outer diameters in the moving direction, that is, in the direction of the central axis Y, and is slidably accommodated in the valve core accommodation portion 510 of the valve housing 51. Specifically, the spool valve core 52 has a first boss portion 521 that is in sliding contact with the first valve core sliding contact portion 511, and a second boss portion 522 that is formed to have a larger diameter than the first boss portion 521 and is in sliding contact with the second valve core sliding contact portion 512. In addition, an intermediate shaft portion 523 having an outer diameter smaller than these first boss portion 521 and second boss portion 522 is formed between the first boss portion 521 and the second boss portion 522. That is, a relay chamber Rc is defined between the intermediate shaft portion 523 and the valve core accommodation portion 510 in the radial direction of the valve housing 51.

[0071] Furthermore, the first boss portion 521 and the second boss portion 522 that are opposed to each other in the direction of the central axis Y in the relay chamber Rc function as pressure-receiving surfaces that receive the oil pressure introduced from the first valve hole 513a. At this time, the second boss portion 522 has a relatively large outer diameter relative to the first boss portion 521, and the second pressure-receiving surface Pf2 formed by the second boss portion 522 is formed relatively large relative to the first pressure-receiving surface Pf1 formed by the first boss portion 521. That is, based on the difference in pressure-receiving area between the first pressure-receiving surface Pf1 and the second pressure-receiving surface Pf2, the oil pressure introduced from the first valve hole 513a into the relay chamber Rc acts on the second pressure-receiving surface Pf2 that is relatively large compared to the first pressure-receiving surface Pf1, and the spool valve element 52 is pushed toward the second end side.

[0072] In addition, the spool valve core 52 has a shaft end 524 on the first end side of the first boss portion 521, and the shaft end 524 has an outer diameter smaller than that of the first boss portion 521. A back pressure chamber Rb is defined between the shaft end 524 and the valve core receiving portion 510 in the radial direction of the valve housing 51. The back pressure chamber Rb captures oil leaking from the relay chamber Rc through the outer peripheral side of the first boss portion 521 (a small gap between the valve core receiving portion 510). It should be noted that the back pressure chamber Rb is connected to the spring receiving chamber 55 through a discharge hole 525 formed on the peripheral wall of the first end of the spool valve core 52 facing the back pressure chamber Rb and an internal passage 526 connecting the discharge hole 525 to the spring receiving chamber 55 described later. That is, the oil collected in the back pressure chamber Rb is introduced into the spring accommodation chamber 55 described later through the discharge hole 525 and the internal passage 526 , and is discharged to the oil pan OP through the discharge port Pd and the discharge passage Ld.

[0073] In addition, the slide valve core 52 has a spring support portion 527 that supports the first end portion of the valve spring 54 that is opposite to the slide valve core 52 at the end portion on the second boss portion 522 side that is opposite to the retaining member 53. The spring support portion 527 is formed by expanding the inner peripheral side of the slide valve core 52 in a stepwise manner toward the second boss portion 522 side, and has a cylindrical spring surrounding portion 527a and a flat spring supporting surface 527b. Thus, the spring support portion 527 surrounds the outer peripheral side of the first end portion of the valve spring 54 with the spring surrounding portion 527a, and supports the first end portion of the valve spring 54 with the spring supporting surface 527b.

[0074] The retaining member 53 is formed into a substantially bottomed cylindrical shape having a cylindrical portion 531 and a bottom wall portion 532 that blocks the outer end of the cylindrical portion 531. The retaining member 53 is embedded in the opening end portion of the second end side of the valve housing 51 in such a manner that the opening portion of the cylindrical portion 531 faces the spring support portion 527 of the slide valve core 52. Thus, the retaining member 53 surrounds the outer peripheral side of the second end of the valve spring 54 through the cylindrical portion 531, and supports the second end of the valve spring 54 through the inner end surface of the bottom wall portion 532. In addition, the stopper member 53 has a circular retaining opening portion 530 at the central position of the bottom wall portion 532. That is, the retaining opening portion 530 passes through the bottom wall portion 532, and connects the second valve hole 514a with the discharge port Pd.

[0075] The valve spring 54 is a known compression coil spring and is loaded with a predetermined preload (set load W2) in a spring housing chamber 55 defined between the spool 52 and the retaining member 53. Thus, the valve spring 54 always urges the spool 52 toward the first end based on the set load W2.

[0076] The solenoid unit 6 includes: a cylindrical housing 61; a coil 62 and an armature 63 housed inside the housing 61; and a rod 64 fixed to the armature 63 and arranged to be able to move forward and backward along the central axis Y direction together with the armature 63. It should be noted that based on the operating state of the engine detected or calculated based on the prescribed parameters such as the oil temperature, water temperature, and engine speed of the engine, an excitation current is passed from the control unit CU to the solenoid unit 6. In addition, the solenoid unit 6 can continuously change the magnitude of the electromagnetic force Fm according to the supplied current value, and is controlled by pulse width modulation (PWM), and its current value is given by the duty cycle Dt.

[0077] (Structure of the discharge passage)

[0078] Figure 3 Indicates that Figure 2 The enlarged view of the main part of the variable displacement pump VP1 is shown in which the vicinity of the discharge passage ER is enlarged and shown. Figure 4 Indicates along Figure 3 A cross-sectional view of the main parts of the variable displacement pump VP1 taken along line A-A.

[0079] like Figure 4 As shown, the first housing 11 is provided with a first discharge port 115a formed by making the bottom wall 111 of the first housing 11 concave in a stepped shape and a first discharge port extension 115b formed by extending the first discharge port 115a radially outward. Moreover, at the front end of the first discharge port extension 115b, a discharge port 115c for discharging the oil of the first discharge port extension 115b to the outside is formed in the form of penetrating the peripheral wall 112 of the first housing 11 and opening at the side of the first housing 11.

[0080] Similarly, a second discharge port 125a formed by making the inner side surface of the second shell 12 concavely depressed and a second discharge port extension 125b formed by extending the second discharge port 125a radially outward on the radially outer side of the second discharge port 125a are provided on the inner side surface of the second shell 12 in a manner opposite to the first discharge port 115a and the first discharge port extension 115b respectively.

[0081] In addition, if Figure 3 As shown, the first discharge port extension 115b and the second discharge port extension 125b are sealed liquid-tightly by the swing support 42 and the second sealing member S2. Figure 4 As shown, a discharge passage ER for guiding the oil discharged to the first discharge port extension portion 115b and the second discharge port extension portion 125b to the discharge port 115c is defined in the first discharge port extension portion 115b and the second discharge port extension portion 125b.

[0082] The discharge passage ER is an oil passage formed in the section from each outlet of the first discharge port 115a and the second discharge port 125a to the inlet of the discharge port 115c. Specifically, the discharge passage ER is composed of a first discharge passage ER1 defined between the first end face FC1 on the axial end side of the cam ring 4 and the first discharge port extension 115b, and a second discharge passage ER2 defined between the second end face FC2 on the axial end side of the cam ring 4 and the second discharge port extension 125b. Moreover, the first discharge passage ER1 and the second discharge passage ER2 merge at the inlet of the discharge port 115c.

[0083] The first discharge passage ER1 is composed of a first bent passage ER1a, which passes through the axially outer side of the first end face FC1 of the cam ring 4 and goes around the radially outer side of the cam ring 4, and a first outlet passage ER1b, which extends from the first bent passage ER1a to the radially outer side of the cam ring 4. Similarly, the second discharge passage ER2 is composed of a second bent passage ER2a, which passes through the axially outer side of the second end face FC2 of the cam ring 4 and goes around the radially outer side of the cam ring 4, and a second outlet passage ER2b, which extends from the second zigzag passage ER2a to the radially outer side of the cam ring 4. The first discharge passage ER1 and the second discharge passage ER2 merge at the first outlet passage ER1b and the second outlet passage ER2b.

[0084] In addition, a first recess 471 is provided on the first end surface FC1 of the cam ring 4, which opens to the discharge passage ER (first discharge passage ER1) and whose axial width (depth) D1 increases from the radial inner side to the radial outer side of the cam ring 4. That is, the first recess 471 is formed in a notch groove shape by chamfering the outer peripheral edge of the first end surface FC1 so that the axial width D1 gradually increases from the middle (radial middle part) of the first end surface FC1 of the cam ring 4 to the radial outer side. The first recess 471 is composed of a first inclined surface 471a that is inclined downward toward the radial outer side of the cam ring 4 when viewed from the first end surface FC side, and a pair of first side surfaces 471b and 471c that stand substantially perpendicularly to the first end surface FC1 on both sides of the first inclined surface 471a. Moreover, the first recess 471 is located in the middle of the first discharge passage ER1, so as to play a function of increasing the flow passage cross-sectional area of ​​the first discharge passage ER1 from the upstream side to the downstream side of the first discharge passage ER1. Furthermore, in the first end surface FC1 of the cam ring 4 , the radial width Wd1 of the region where the first recessed portion 471 is formed is set larger than the minimum value of the radial width Wd2 of the other regions.

[0085] Similarly, a second recess 472 is provided on the second end surface FC2 of the cam ring 4, which opens to the discharge passage ER (second discharge passage ER2) and whose axial width (depth) D2 increases from the radial inner side to the radial outer side of the cam ring 4. That is, the second recess 472 is formed in a notch groove shape by chamfering the outer peripheral edge of the second end surface FC2 so that the axial width D2 gradually increases from the middle (radial middle part) of the second end surface FC2 of the cam ring 4 to the radial outer side. The second recess 472 is composed of a second inclined surface 472a that is inclined downward toward the radial outer side of the cam ring 4 when viewed from the second end surface FC2 side, and a pair of second side surfaces 472b and 472c that stand up substantially perpendicularly to the second end surface FC2 on both sides of the second inclined surface 472a. Moreover, the second recess 472 is located in the middle of the second discharge passage ER2, thereby playing a function of increasing the flow passage cross-sectional area of ​​the second discharge passage ER2 from the upstream side to the downstream side of the second discharge passage ER2. Further, similarly to the first end surface FC1 side, also on the second end surface FC2 of the cam ring 4 , the radial width Wd1 of the region where the second recessed portion 472 is formed is set larger than the minimum value of the radial width Wd2 of the other regions.

[0086] Here, the first inclined surface 471a of the first recess 471 and the second inclined surface 472a of the second recess 472 can be set to any inclination angle according to the performance and manufacturing cost required by the variable displacement pump VP1. On the other hand, the angle formed by the first inclined surface 471a and the first end surface FC1, i.e., the first inclination angle θ1, is preferably set in the range of "0°<θ1≤45°". Similarly, the angle formed by the second inclined surface 472a and the second end surface FC2, i.e., the second inclination angle θ2, is preferably set in the range of "0°<θ1≤45°". Regarding the basis for the first inclination angle θ1 and the second inclination angle θ2, based on Figure 7 , Figure 8 This will be explained later.

[0087] In addition, the first recessed portion 471 is preferably arranged on the inner peripheral side of the cam ring 4 (close to the pump assembly storage portion 41) in the radial middle portion of the first end surface FC1. The same is true for the second recessed portion 472, which is preferably arranged on the inner peripheral side of the cam ring 4 (close to the pump assembly storage portion 41) in the radial middle portion of the second end surface FC2. As a result, the cross-sectional area of ​​the flow passages of the first discharge passage ER1 and the second discharge passage ER2 gradually increases from a position closer to the upstream side, and the pressure loss in the first discharge passage ER1 and the second discharge passage ER2 can be more effectively reduced.

[0088] (Pump Operation Description)

[0089] Next, based on Figure 2 , Figures 5 to 8 The operation of the variable displacement pump VP1 according to the present embodiment will be described.

[0090] In the variable displacement pump VP1 of this embodiment, as Figure 2 As shown, the rotation of the engine (crankshaft) (not shown) is transmitted to the drive shaft 2 via the chain (not shown), and the rotor 31 is driven to rotate in the rotation direction D via the drive shaft 2. Then, along with the rotation of the rotor 31, the oil is sucked up from the oil pan OP via the suction port 114c, the first suction port 114a, and the second suction port (not shown). In addition, at the same time as this suction action, the oil is guided to the discharge passage Le via the first discharge port 115a and the second discharge port (not shown), the first and second discharge port extensions 115b, 125b, and the discharge port 115c. Then, the oil guided to the discharge passage Le is pressed to the sliding part (crank metal CM) of the engine (not shown), the injection device OJ, and the valve timing control device VT, etc. (not shown) via the main oil gallery MG, and is guided to the introduction port Pb of the control valve SV via the discharge pressure introduction passage Lb. It should be noted that an oil pressure sensor PS capable of detecting the discharge pressure P is arranged in the main oil gallery MG, and the detection result of the oil pressure sensor PS is fed back to the control unit CU.

[0091] In addition, the cam ring 4 swings with the pivot pin 40 as a fulcrum, and the eccentricity Δ changes, and the volume change amount (the difference between the maximum volume and the minimum volume) of the pump chamber 30 changes. If the eccentricity Δ increases, the volume change amount of the pump chamber 30 also increases, and if the eccentricity Δ decreases, the volume change amount of the pump chamber 30 also decreases. In addition, the eccentricity Δ changes according to the force in the concentric direction based on the internal pressure of the first control oil chamber PR1 (the first control oil pressure P1) and the force in the eccentric direction based on the internal pressure of the second control oil chamber PR1 (the second control oil pressure P2) and the set load W1 of the coil spring SP. That is, when the force in the concentric direction based on the internal pressure of the first control oil chamber PR1 (the first control oil pressure P1) is smaller than the force in the eccentric direction based on the internal pressure of the second control oil chamber PR1 (the second control oil pressure P2) and 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 force in the concentric direction based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) is greater than the force in the eccentric direction based on the internal pressure of the second control oil chamber PR1 (second control oil pressure P2) and the set load W1 of the coil spring SP, the cam ring 4 swings in the concentric direction and the eccentric amount Δ decreases. In addition, the cam ring 4 stops at a position where the force in the concentric direction based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) and the force in the eccentric direction based on the internal pressure of the second control oil chamber PR1 (second control oil pressure P2) and the set load W1 of the coil spring SP are balanced.

[0092] (Control valve operation description)

[0093] Figure 5Graph showing the discharge pressure characteristics of the variable displacement pump VP1. Figure 6 The hydraulic circuit diagram showing the working state of the variable displacement pump VP1 is shown in (a). Figure 5 The state of the pump in interval a, (b) represents Figure 5 The state of the pump in interval b. In addition, Figure 7 The hydraulic circuit diagram showing the working state of the variable displacement pump VP1 is shown in (a). Figure 5 The state of the pump in interval c, (b) represents Figure 5 The state of the pump in interval d. In addition, Figure 8 The hydraulic circuit diagram showing the working state of the variable displacement pump VP1 is shown in (a). Figure 5 The state of the pump in interval e, (b) represents Figure 5 The state of the pump in the interval f.

[0094] Figure 5 P1 in , for example, represents the first internal combustion engine required oil pressure, which corresponds to the required oil pressure of the valve timing control device VT. Figure 5 P2 in φ represents a second internal combustion engine required oil pressure, which corresponds to the required oil pressure of the oil injection device OJ for cooling the piston of the engine, for example. Figure 5 P3 in the figure represents a third internal combustion engine required oil pressure which is required for lubrication of a bearing portion (crankshaft metal CM) of a crankshaft when the engine rotates at a high speed, for example.

[0095] That is, the variable displacement pump VP1 introduces the first control oil pressure P1 into the first control oil chamber PR1 via the first passage L1 branched from the discharge pressure introduction passage Lb in the interval a from the start of the internal combustion engine to the rotation speed Na. In addition, the force Po generated by the discharge pressure P acting on the second pressure receiving surface Pf2 of the spool valve core 52 of the control valve SV is smaller than the set load W2 of the valve spring 54. Therefore, as Figure 6 As shown in (a), the spool 52 is maintained at the initial position, i.e., the position on the first end side, the inlet port Pb is connected to the supply and discharge port Pc (first state), and the second control oil pressure P2 is introduced into the second control oil chamber PR2. As a result, the combined force of the oil pressure 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 oil pressure 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 maintains the maximum eccentric state.

[0096] Finally, when the discharge pressure P reaches the first internal combustion engine required oil pressure P1, the duty ratio Dt of the excitation current supplied to the solenoid portion 6 is set to 100% while maintaining the discharge pressure P at the first internal combustion engine required oil pressure P1. As a result, the electromagnetic force Pm generated in the solenoid portion 6, that is, the pressing force of the rod 64 on the spool valve element 52, is greater than the set load W2 of the valve spring 54. Therefore, as Figure 6 As shown in (b), the spool valve core 52 moves toward the second end side, the connection between the inlet port Pb and the supply and discharge port Pc is cut off, and the supply and discharge port Pc is connected to the discharge port Pd (second state). Figure 5 In the interval b, 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 discharge pressure P introduced into the first control oil chamber PR1 acts on the first pressure receiving surface 441 to generate an oil pressure Fp1 that exceeds the set load W1 of the coil spring SP. As a result, as the discharge pressure P increases, the eccentricity Δ of the cam ring 4 decreases, and the discharge pressure P slowly increases.

[0097] In the variable displacement pump VP1, when the engine speed N is greater than the speed Na and less than the speed Nc, Figure 5 The interval c or interval e, such as Figure 7 (a) and Figure 8 As shown in (a), the 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 core 52 is smaller than the set load W2 of the valve spring 54. Figure 7 (a) Figure 8 As shown in (a), the spool 52 is maintained at the initial position, i.e., the position on the first end side, the inlet port Pb is connected to the supply and discharge port Pc (first state), and the second control oil pressure P2 is introduced into the second control oil chamber PR2. As a result, the combined force of the oil pressure Fp2 generated by the second control oil pressure P2 introduced into 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 oil pressure Fp1 generated by the oil pressure in the first control oil chamber PR1 acting on the first pressure receiving surface 441, and the cam ring 4 maintains the maximum eccentric state.

[0098] On the other hand, in the range where the engine speed N is less than the speed Nc, the eccentricity Δ of the cam ring 4 can be controlled by steplessly changing the current value (duty ratio Dt) of the excitation current supplied to the solenoid portion 6. Specifically, for example, when the discharge pressure P is maintained at the second internal combustion engine required oil pressure P2, the duty ratio Dt of the excitation current supplied to the solenoid portion 6 is set to approximately 50%. As a result, the combined force Po of the discharge pressure P and the electromagnetic force Pm of the solenoid portion 6 is greater than the set load W2 of the valve spring 54. Thus, as Figure 7As shown in (b), the spool valve core 52 moves toward the second end side, the communication between the inlet port Pb and the supply and discharge port Pc is cut off, and the supply and discharge port Pc is connected to the discharge port Pd (second state). As a result, in the above-mentioned interval 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 discharge pressure P (first control oil pressure P1) of the first control oil chamber PR1 acts on the first pressure receiving surface 441 to generate an oil pressure Fp1 that exceeds the set load W1 of the coil spring SP. As a result, with the increase of the discharge pressure P, the eccentricity Δ of the cam ring 4 decreases and becomes the minimum eccentricity state, and the discharge pressure P is maintained at the second internal combustion engine required oil pressure P2.

[0099] It should be noted that in the above-mentioned interval d, the movement of the slide valve core 52 toward the second end side due to the increase of the above-mentioned discharge pressure P, and the movement of the slide valve core 52 toward the first end side due to the movement of the slide valve core 52 toward the second end side and the cam ring 4 being in the minimum eccentric state are repeated alternately and continuously. In this way, the discharge pressure P is maintained at the second internal combustion engine required oil pressure P2 by alternately and continuously switching the state in which the supply and discharge port Pc is connected to the introduction port Pb and the state in which the supply and discharge port Pc is connected to the discharge port Pd.

[0100] Finally, when the discharge pressure P reaches the third internal combustion engine required oil pressure P3, the force Po of the discharge pressure P becomes larger than the set load W2 of the valve spring 54 when the duty ratio Dt of the excitation current supplied to the solenoid portion 6 is 0%. Figure 8 As shown in (b), the spool valve core 52 moves toward the second end side, and the inlet port Pb is connected to the supply and discharge port Pc. Figure 5 In the interval f, 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 discharge pressure P (first control oil pressure P1) of the first control oil chamber PR1 acts on the first pressure receiving surface 441 to generate an oil pressure Fp1 that exceeds the set load W1 of the coil spring SP. As a result, as the discharge pressure P increases, the eccentricity Δ of the cam ring 4 decreases to a minimum eccentricity state, and the discharge pressure P is maintained at the second internal combustion engine required oil pressure P3.

[0101] It should be noted that, in the above-mentioned interval f, similarly to the above-mentioned interval d, the movement of the slide valve core 52 toward the second end side due to the increase of the above-mentioned discharge pressure P and the movement of the slide valve core 52 toward the first end side accompanied by the movement of the slide valve core 52 toward the second end side and the cam ring 4 being in the minimum eccentric state are alternately and continuously repeated. In this way, the discharge pressure P is maintained at the third internal combustion engine required oil pressure P3 by alternately switching the state in which the supply and discharge port Pc is connected to the introduction port Pb and the state in which the supply and discharge port Pc is connected to the discharge port Pd.

[0102] (Effects of this embodiment)

[0103] Fig. 9 1 is a diagram showing a CFD analysis diagram of the discharge passage ER, (a) showing the variable displacement pump of the present embodiment, and (b) showing a conventional variable displacement pump. Fig.10 A graph comparing the pressure loss of the variable displacement pump according to the present embodiment and the pressure loss of a conventional variable displacement pump is shown.

[0104] like Fig. 9 As shown in (b), in the above-mentioned conventional variable displacement pump VP0, the first end face FC1 of the cam ring 4 is formed to be substantially parallel to the inner side face of the second housing 12, and the second end face FC2 of the cam ring 4 is formed to be substantially parallel to the bottom wall 111 of the first housing 11. Therefore, when the oil flowing into the first discharge port extension 115b and the second discharge port extension 125b flows into the discharge port 115c along the first end face FC1 and the second end face FC2 of the cam ring 4, a large number of eddies are generated near the outer peripheral edge portions of the first end face FC1 and the second end face FC2 of the cam ring 4 (refer to the X portion in the figure), and there is room for improvement in the point that the pressure loss of the pump is generated due to the eddies.

[0105] In contrast, the variable displacement pump VP1 of the present embodiment comprises: a housing 1 (first housing 11) having a pump housing 110, and a suction portion (first suction portion 114) and a discharge portion (first discharge portion 115) opening into the pump housing 110; a cam ring 4 movably disposed inside the pump housing 110; a pump assembly 3 disposed on the inner circumference of the cam ring 4 and having a rotor 31 driven to rotate, and a plurality of blades 32 capable of moving in and out of the radially outer side of the rotor 31, wherein the pump assembly 3 is provided with a plurality of blades 32 disposed on the inner circumference of the cam ring 4 and having a plurality of blades 32 capable of moving in and out of the radially outer side of the rotor 31. A plurality of pump chambers 30 are formed between the component 3 and the cam ring 4; a discharge passage ER (first discharge passage ER1) which guides the oil discharged from the pump chamber 30 to the discharge portion (first discharge portion 115) across the end face FC1 on one axial side of the cam ring 4 and toward the discharge port 115c located on the radial outer side of the cam ring 4; a first recess 471 which is arranged on the first end face FC1 and opens to the discharge passage ER (first discharge passage ER1), and the axial width (depth) D1 increases from the radial inner side to the outer side of the cam ring 4.

[0106] Thus, in the variable displacement pump VP1 of the present embodiment, Fig. 9As shown in (a), a first recess 471 is provided on the first end face FC1 of the cam ring 4, which opens to the first discharge passage ER1 and has an axial width (depth) D1 that increases from the radial inside to the outside of the cam ring 4. Therefore, the first recess 471 can suppress a sudden change in the flow path cross-sectional area of ​​the first discharge passage ER1 (especially near the outer peripheral edge of the first end face FC1 of the cam ring 4). As a result, the generation of eddy currents near the outer peripheral edge of the first end face FC1 of the cam ring 4 (refer to the X portion in the figure) can be suppressed, as shown in FIG. Fig.10 As shown, the pressure loss of the pump can be reduced compared to the conventional variable displacement pump VP0.

[0107] In the variable displacement pump VP1 of the present embodiment, the first recess 471 opens toward the radially outer side of the cam ring 4 from between the inner and outer peripheral surfaces of the cam ring 4 (at an intermediate position) in the radial direction of the cam ring 4 .

[0108] Thus, in the present embodiment, the first recessed portion 471 is configured to be not open to the inner peripheral surface of the cam ring 4 from the middle of the radial width at the first end surface FC1 of the cam ring 4. This can suppress the reduction of the inner peripheral surface of the cam ring 4, that is, the sliding contact surface of the vane 32. As a result, the reduction in the wear resistance of the cam ring 4 that accompanies the reduction in the sliding contact surface of the vane 32 can be suppressed.

[0109] In the variable displacement pump VP1 of the present embodiment, the first recessed portion 471 is an inclined surface whose axial width gradually increases from the radially inner side to the radially outer side of the cam ring 4 .

[0110] Thus, in this embodiment, the first recess 471 is formed by the first inclined surface 471a, so that the flow path cross-sectional area of ​​the discharge passage ER (first discharge passage ER1) can be gradually increased. Thus, compared with the case where the first recess 471 is formed in a stepped shape as in the second embodiment described later, the pressure loss of the pump can be effectively reduced.

[0111] In addition, in the variable displacement pump VP1 of the present embodiment, the first discharge passage ER1 has: a bending passage (first bending passage ER1a) that passes through the axial outer side of the cam ring 4 and goes around the radial outer side of the cam ring 4; an outlet passage (first outlet passage ER1b) that extends from the bending passage (first bending passage ER1a) to the radial outer side of the cam ring 4; and an outlet passage is provided on the extension line of the first inclined surface 471a.

[0112] Thus, in the present embodiment, the first outlet passage ER1b is provided on the extension line of the first inclined surface 471a. Therefore, the oil flowing along the first recessed portion 471 can be smoothly guided to the first outlet passage ER1b. Thus, the pressure loss of the pump can be more effectively reduced.

[0113] In addition, the variable displacement pump VP1 of the present embodiment also has: a second discharge passage ER2, which guides the oil discharged from the pump chamber 30 to the discharge portion (first discharge portion 115) across the end face on the other axial side of the cam ring 4, namely, the second end face FC2, to the discharge port located radially outside the cam ring 4; a second recess 742, which is arranged on the second end face FC2, faces the second discharge passage ER2, and opens on the radial outside of the cam ring 4, and the axial width increases from the radial inside to the outside of the cam ring 4.

[0114] Thus, in this embodiment, recesses (first recess 741 and second recess 742) are provided at both axial ends of the cam ring 4. Therefore, the generation of vortexes can be suppressed for the oil that flows from both axial ends of the cam ring 4 to the radial outer side of the cam ring 4. Thus, the pressure loss of the pump can be more effectively reduced.

[0115] In the variable displacement pump VP1 of the present embodiment, the radial width Wd1 of the region of the cam ring 4 where the first recessed portion 471 is formed is larger than the minimum value of the radial width Wd2 of the other regions.

[0116] Thus, in this embodiment, the radial width Wd1 of the region where the first recess 471 is formed is set larger than the minimum value of the radial width Wd2 of other regions. Therefore, the first recess 471 can be formed longer in the radial direction of the cam ring 4, and the pressure loss of the pump can be reduced more effectively.

[0117] Fig.11 The first inclined surface 471a is represented by the inclination angle Figure 4 An enlarged view of the main part. Fig.12 It is a graph showing the pressure loss at different inferior angles θ between the first inclined surface 471 a and the first end surface FC1 .

[0118] like Fig.11 As shown, in the variable displacement pump VP1 of the present embodiment, the inclination angle of the first inclined surface 471a, that is, the inferior angle θ between the first inclined surface 471a and the first end surface FC1 is set in the range of "0<θ≤45°". In addition, by setting the inferior angle θ in the range of "0<θ≤45°", the discharge port 115c is located on the extension line of the first inclined surface 471a.

[0119] Here, if the pressure loss of the pump is compared according to the inferior angle θ between the first inclined surface 471a and the first end surface FC1, Fig.12 As shown in FIG. 1 , when the inferior angle θ is between 0° and 25°, the pressure loss of the pump decreases inversely proportional to the increase of the inferior angle θ, and when the inferior angle θ is around 25°, the pressure loss of the pump is the smallest. On the other hand, with the inferior angle θ around 25° as the boundary, the pressure loss of the pump gradually increases in direct proportion to the increase of the inferior angle θ.

[0120] As described above, in the present embodiment, the inferior angle θ between the first inclined surface 471a and the first end surface FC1 is set in the range of "0<θ≤45°". Thus, compared with the conventional variable displacement pump which has no inclined surface on the axial end surface of the cam ring 4, i.e., the inferior angle θ is 0°, the generation of eddy current on the end side of the first inclined surface 471a can be effectively suppressed, and the pressure loss of the pump can be effectively reduced.

[0121] [Second embodiment]

[0122] Figure 13-14 The second embodiment of the variable displacement pump of the present invention is shown. It should be noted that the present embodiment changes the form of the first recess 741 and the second recess 742 of the first embodiment, and the other structures are the same as the first embodiment. Therefore, the same figure mark is marked for the same structure as the first embodiment, and its description is omitted.

[0123] Fig.13 The structure of the variable displacement pump VP2 of the present embodiment is shown, and a plan view of the variable displacement pump VP2 is shown in which the second housing 12 is removed from the variable displacement pump VP2. Fig.14 Indicates along Fig.13 A cross-sectional view of the main parts of the variable displacement pump VP2 taken along line BB.

[0124] (Pump Structure)

[0125] like Fig.13 As shown, in the variable displacement pump VP2 of this embodiment, the first recess 471 is formed Fig.14 More specifically, the first recessed portion 471 is defined by a horizontal bottom surface 471d formed in a substantially horizontal shape, a pair of first side surfaces 471b and 471c rising substantially vertically from both sides of the horizontal bottom surface 471d, and a vertical end surface 471e that is substantially vertically recessed at the beginning of the first recessed portion 471 and connects the pair of first side surfaces 471b and 471c to each other. Here, the horizontal bottom surface 471d and the vertical end surface 471e are preferably formed by Fig.14 That is, the horizontal bottom surface 471d and the vertical end surface 471e are connected by the smooth arc surface 471f, so that the flow path cross-sectional area can be gradually increased from the radial inside to the outside of the first recess 471.

[0126] The second recess 472 is also formed similarly to the first recess 471. Fig.14The second recess 472 is in a roughly rectangular shape when viewed in cross section, and is defined by a horizontal bottom surface 472d formed in a roughly horizontal shape, a pair of second side surfaces 472b and 472c rising roughly vertically from both sides of the horizontal bottom surface 472d, and a vertical end surface 472e which is roughly vertically recessed at the starting end portion of the second recess 472 and connects the pair of second side surfaces 472b and 472c to each other.

[0127] In addition, the horizontal bottom surface 472d and the vertical end surface 472e are preferably connected by Fig.14 That is, the horizontal bottom surface 472d and the vertical end surface 472e are connected by the smooth arc surface 472f, thereby enabling the flow path cross-sectional area to gradually increase from the radial inside to the outside.

[0128] (Effects of this embodiment)

[0129] As described above, in the variable displacement pump VP2 of the present embodiment, the first recess 471 and the second recess 472 are respectively formed into a substantially rectangular recess in cross-sectional view. In this way, by using the first recess 471 and the second recess 472 to recess the outer peripheral sides of the first end face FC1 and the second end face FC2, as in the first embodiment, the first recess 471 and the second recess 472 can be used to suppress the rapid change in the cross-sectional area of ​​the flow path at the first discharge passage ER1 (near the outer peripheral edge of the first end face FC1 of the cam ring 4) and the second discharge passage ER2 (near the outer peripheral edge of the second end face FC2 of the cam ring 4). As a result, the generation of eddy currents near the outer peripheral edges of the first end face FC1 and the second end face FC2 of the cam ring 4 can be suppressed, such as Fig.10 As shown, the pressure loss of the pump can be reduced compared to the conventional variable displacement pump VP0.

[0130] In addition, in particular, in the present embodiment, the first recess 471 and the second recess 472 are formed in a stepped shape that is a substantially rectangular recess in cross section, so that the life of the die for sintering the cam ring 4 can be prolonged compared to the case where the first recess 471 and the second recess 472 are formed in an inclined shape as in the first embodiment. That is, in the case where the first recess 471 and the second recess 472 are formed in an inclined shape, the cross section of the convex portion forming the first recess 471 and the second recess 472 is formed in a substantially triangular shape, so the life of the die for sintering the cam ring 4 may become short. On the other hand, as in the present embodiment, by forming the first recess 471 and the second recess 472 in a stepped shape (rectangular recess), the convex portion forming the first recess 471 and the second recess 472 can be formed in a substantially rectangular cross section, and the life of the die for sintering the cam ring 4 can be prolonged.

[0131] [Third Embodiment]

[0132] Fig.15 The third embodiment of the variable capacity pump of the present invention is shown. It should be noted that the present embodiment changes the form of the first discharge port extension 115b and the second discharge port extension 125b of the first embodiment, and the other structures are the same as the first embodiment. Therefore, the same figure mark is marked for the same structure as the first embodiment, and its description is omitted.

[0133] Fig.15 The variable displacement pump VP3 of this embodiment is equivalent to Figure 4 .

[0134] (Pump Structure)

[0135] like Fig.15 As shown, in the variable displacement pump VP3 of this embodiment, the first discharge port extension 115b is formed with a first recessed inclined surface 115d which is an inclined surface opposite to the first recessed portion 471. Similarly, the second discharge port extension 125b is formed with a second recessed inclined surface 125d which is an inclined surface opposite to the second recessed portion 472.

[0136] The first recessed inclined surface 115d and the second recessed inclined surface 125d are each formed in an inclined shape such that the distance from the center G of the discharge port 115c gradually decreases toward the discharge port 115c. More specifically, the first recessed inclined surface 115d has a smaller inclination angle than the first inclined surface 471a, and is formed such that the distance Ld1 from the first inclined surface 471a increases toward the discharge port 115c. Similarly, the second recessed inclined surface 125d has a smaller inclination angle than the second inclined surface 472a, and is formed such that the distance Ld2 from the second inclined surface 472a increases toward the discharge port 115c.

[0137] It should be noted that the first recessed inclined surface 115d and the second recessed inclined surface 125d only need to be formed so that the distance from the center G of the discharge port 115c gradually decreases toward the discharge port 115c. Therefore, in addition to the tapered surface exemplified in this embodiment, the first recessed inclined surface 115d and the second recessed inclined surface 125d may also be formed, for example, Fig.15 In the cross-sectional view shown, the distance from the center G of the discharge port 115c gradually decreases toward the discharge port 115c side.

[0138] (Effects of this embodiment)

[0139] As described above, in the variable displacement pump VP3 of the present embodiment, the first recessed portion inclined surface 115 d facing the first recessed portion 471 is provided on the inner side surface of the housing (first housing 11 ) facing the radially outer side of the cam ring 4 .

[0140] Thus, in this embodiment, in addition to the first recess 471 provided on the cam ring 4 side, a first recess inclined surface 115d is also provided on the first housing 11 side, thereby more effectively suppressing the generation of vortex on the outlet side of the first discharge passage ER1 and more effectively reducing the pressure loss of the pump.

[0141] The first recessed portion inclined surface 115 d is formed so that a distance Ld1 from the first recessed portion 471 increases toward the radially outer side of the cam ring 4 .

[0142] Thus, according to the present embodiment, the first recessed inclined surface 115d is formed so that the distance Ld1 from the first recessed portion 471 increases as it moves toward the radially outer side of the cam ring. Therefore, in the present embodiment, regarding the discharge passage ER, the flow passage cross-sectional area toward the outlet side of the first discharge passage ER1 increases, and the flow passage resistance of the oil can be reduced. Thus, the pressure loss of the pump can be more effectively reduced.

[0143] [Fourth Embodiment]

[0144] Fig.16 and Fig.17 The fourth embodiment of the variable displacement pump of the present invention is shown. It should be noted that the present embodiment changes the structure of the first end face FC1 and the second end face FC2 of the cam ring 4 in the first embodiment, and the other structures are the same as the first embodiment. Therefore, the same figure mark is marked on the same structure as the first embodiment, and its description is omitted.

[0145] Fig.16 The structure of the variable displacement pump VP4 of the present embodiment is shown, and a plan view of the variable displacement pump VP4 is shown in a state where the second housing 12 is removed from the variable displacement pump VP4. Fig.17 Indicates along Fig.16 A cross-sectional view of the main parts of the variable displacement pump VP4 taken along line CC.

[0146] like Fig.16 , Fig.17 As shown, the variable displacement pump VP4 of this embodiment is formed with a first connecting groove 481 that connects the inner circumference and the outer circumference of the cam ring 4 at a position opposite to the first discharge passage ER1 in the first end surface FC1 of the cam ring 4. The first connecting groove 481 has a shape corresponding to the first discharge port 115a and the first discharge port extension 115b, and is formed relatively wide along the circumferential direction at the starting end (inner end) overlapping with the first discharge port 115a, and is formed to have a substantially constant groove width corresponding to the first discharge port extension 115b from the middle portion overlapping with the first discharge port extension 115b to the terminal side. In addition, a first recess 471 is formed on the bottom surface of the terminal side of the first connecting groove 481.

[0147] Similarly, a second connecting groove 482 is formed at a position opposite to the second discharge passage ER2 on the second end surface FC2 of the cam ring 4, which connects the inner circumference and the outer circumference of the cam ring 4. The second connecting groove 482 also has a shape corresponding to the second discharge port 125a and the second discharge port extension 125b, and is formed to be relatively wide along the circumferential direction at the starting end (inner end) overlapping the second discharge port 125a, and is formed to have a substantially constant groove width corresponding to the second discharge port extension 125b from the middle portion overlapping the second discharge port extension 125b to the terminal side. In addition, a second recess 472 is formed on the bottom surface of the terminal side of the second connecting groove 482.

[0148] (Effects of this embodiment)

[0149] As described above, in the variable displacement pump VP4 of the present embodiment, the cam ring 4 has a first connecting groove 481 connecting the inner peripheral side and the outer peripheral side of the cam ring 4 at a position opposite to the discharge passage ER (first discharge passage ER1) in the first end surface FC1, and the first recess 471 is formed on the bottom surface of the first connecting groove 481.

[0150] In this way, by providing the first connecting groove 481 that connects the inner circumference and the outer circumference of the cam ring 4 on the first end surface FC1 of the cam ring 4, the flow path cross-sectional area of ​​the discharge passage ER (first discharge passage ER1) is ensured to be larger by the amount of the first connecting groove 481, and the flow path resistance of the oil can be reduced. As a result, the pressure loss of the pump can be more effectively reduced.

[0151] (Variation Example)

[0152] Fig.18 A modified example of the fourth embodiment of the variable capacity pump of the present invention is shown. It should be noted that this embodiment changes the form of the first discharge port extension 115b and the second discharge port extension 125b of the fourth embodiment, and the other structures are the same as the fourth embodiment. Therefore, the same figure mark is marked on the same structure as the fourth embodiment, and its description is omitted.

[0153] Fig.18 is equivalent to Fig.16 The CC line cross-section diagram is a cross-sectional view of the main parts of this modified example.

[0154] like Fig.18As shown, the variable displacement pump VP4′ of this modified example is obtained by adding the first recessed inclined surface 115d and the second recessed inclined surface 125d of the variable displacement pump VP3 of the third embodiment to the variable displacement pump VP4 of the fourth embodiment. That is, the variable displacement pump VP4′ is formed with the first recessed inclined surface 115d, which is an inclined surface opposite to the first recessed portion 471, in the first discharge port extension 115b. Similarly, the second recessed inclined surface 125d, which is an inclined surface opposite to the second recessed portion 472, is formed in the second discharge port extension 125b.

[0155] The first recessed inclined surface 115d and the second recessed inclined surface 125d are each formed in an inclined shape such that the distance from the center G of the discharge port 115c gradually decreases toward the discharge port 115c side. That is, the first recessed inclined surface 115d is preferably formed to have a smaller inclination angle than the first inclined surface 471a, and the distance Ld1 from the first inclined surface 471a increases toward the discharge port 115c side. Similarly, the second recessed inclined surface 125d is preferably formed to have a smaller inclination angle than the second inclined surface 472a, and the distance Ld2 from the second inclined surface 472a increases toward the discharge port 115c side.

[0156] It should be noted that the first recessed inclined surface 115d and the second recessed inclined surface 125d only need to be formed so that the distance from the center G of the discharge port 115c gradually decreases toward the discharge port 115c. Therefore, in addition to the tapered surface exemplified in this embodiment, the first recessed inclined surface 115d and the second recessed inclined surface 125d may also be formed, for example, Fig.15 In the cross-sectional view shown, the distance from the center G of the discharge port 115c gradually decreases toward the discharge port 115c side.

[0157] As described above, according to the variable capacity pump VP4' of this modified example, by adding the structure of the variable capacity pump VP3 of the third embodiment to the variable capacity pump VP4 of the fourth embodiment, it is possible to achieve both the effects of the variable capacity pump VP3 of the third embodiment and the effects of the variable capacity pump VP4 of the fourth embodiment.

[0158] The present invention is not limited to the configuration of the above-described embodiment and the like, and can be freely changed according to, for example, the engine of a vehicle equipped with the variable displacement pumps VP1 to VP4, the specifications of the valve timing control device, and the like.

[0159] In addition, in the above-mentioned embodiments, the form of the so-called swing type cam ring 4 is used to make the discharge amount of the pump variable by swinging the cam ring 4. However, as a means for making the discharge amount of the pump variable, it is not limited to the above-mentioned swinging, for example, it can also be performed by moving (sliding) the cam ring 4 linearly in the radial direction. In other words, as long as it is a structure that can change the discharge amount of the pump (a structure that can change the volume change amount of the pump chamber 30), the movement form of the cam ring 4 is not limited.

Claims

1. A variable capacity pump, characterized in that: have: a housing having a pump housing portion, and a suction portion and a discharge portion opening into the pump housing portion; a cam ring movably disposed inside the pump housing; a pump assembly disposed on the inner circumference side of the cam ring and having a rotor driven to rotate and a plurality of blades capable of moving in and out of the radially outer side of the rotor, wherein a plurality of pump chambers are formed between the pump assembly and the cam ring; a first discharge passage for guiding the fluid discharged from the pump chamber to the discharge portion to a discharge port located radially outside the cam ring across a first end surface that is an end surface on one axial side of the cam ring; and The first recessed portion is provided on the first end surface, opens to the first discharge passage, and has an axial width that increases from the radial inner side to the radial outer side of the cam ring.

2. The variable displacement pump according to claim 1, characterized in that: The first recessed portion starts between an inner peripheral surface and an outer peripheral surface of the cam ring in a radial direction of the cam ring and opens toward a radially outer side of the cam ring.

3. The variable displacement pump according to claim 1, characterized in that: The first recessed portion is an inclined surface whose axial width gradually increases from the radial inner side to the radial outer side of the cam ring.

4. The variable displacement pump according to claim 3, characterized in that: The first discharge passage has: a bent passage that passes axially outside the cam ring and winds around to the radially outside of the cam ring; and an outlet passage extending from the bent passage toward the radially outer side of the cam ring; The outlet passage is provided on an extension line of the inclined surface.

5. The variable displacement pump according to claim 3, characterized in that: A minor angle θ between the inclined surface and the first end surface is set within a range of “0°<θ≤45°”.

6. The variable displacement pump according to claim 1, characterized in that: Also features: a second discharge passage for guiding the fluid discharged from the pump chamber to the discharge portion to a discharge port located radially outside the cam ring across a second end surface that is the other end surface in the axial direction of the cam ring; and The second recessed portion is provided on the second end surface, faces the second discharge passage, opens radially outward of the cam ring, and has an axial width increasing from the radially inner side to the radially outer side of the cam ring.

7. The variable displacement pump according to claim 1, characterized in that: The radial width of a region of the cam ring where the first recessed portion is formed is larger than a minimum value of radial widths of other regions.

8. The variable displacement pump according to claim 1, characterized in that: The housing has an inclined surface facing the first recessed portion on an inner side surface facing the radially outer side of the cam ring.

9. The variable displacement pump according to claim 8, characterized in that: The inclined surface is formed so that a distance from the first recessed portion increases toward the radially outer side of the cam ring.

10. The variable displacement pump according to claim 1, characterized in that The cam ring has a connecting groove connecting the inner peripheral side and the outer peripheral side of the cam ring at a position of the first end surface facing the first discharge passage. The first recess is formed on the bottom surface of the communicating groove.

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