Variable displacement oil pump and method for manufacturing variable displacement oil pump

Abstract

A variable displacement oil pump according to the present invention has a protrusion (46) partially formed on a spring contact surface (451) of an arm section (45) of a cam ring (4) so as to overlap a part of the outer periphery of a coil spring (SP). The protrusion (46) is used for limiting the tilting of the spiral spring (SP), and the position deviation of the spiral spring (SP) can be restrained. Furthermore, since the projection (46) is partially provided on the spring contact surface (451) of the arm section (45) of the cam ring (4), when the coil spring (SP) is assembled, only the coil spring (SP) is pushed into the projection (46), thereby ensuring ease of assembly of the coil spring (SP).

Description

Technical Field

[0001] The present invention relates to a variable capacity oil pump and a method for manufacturing the variable capacity oil pump. Background Art

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

[0003] In the variable displacement oil pump described in Patent Document 1, a cam ring is swingably disposed in a pump housing of a housing, a coil spring is in elastic contact with an arm portion disposed on the opposite side of a swing fulcrum across the center of the cam ring, and the cam ring is urged in a direction of increasing eccentricity by the force of the coil spring. Furthermore, in the urging mechanism, a cylindrical protrusion protruding from a spring contact surface of the arm portion of the cam ring is fitted into the inner circumference of the coil spring, and the inner circumference of one end portion of the coil spring (the end portion seated on the cam ring side) is supported by the protrusion, thereby suppressing positional deviation of the coil spring.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: (Japanese) Patent Publication No. 2019-019716 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] However, in the above-mentioned conventional variable capacity oil pump, the protrusion is fitted into the inner circumference of the coil spring. Therefore, when assembling the coil spring, the compressed coil spring must be restored and the protrusion must be fitted into the inner circumference of the coil spring, which makes the assembly of the coil spring difficult. 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 oil pump, and an object of the present invention is to provide a variable displacement oil pump capable of ensuring ease of assembly of a coil spring and suppressing positional deviation of the coil spring.

[0010] Technical solutions for solving technical problems

[0011] As one aspect of the present invention, the cam ring is provided with a protrusion that is partially formed so as to extend from a spring contact surface with which the coil spring contacts in the longitudinal direction of the coil spring and overlap a portion of the outer circumference of the coil spring.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to suppress positional deviation of the coil spring while ensuring ease of assembly of the coil spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an exploded perspective view of a pump body of the variable displacement oil pump of the present invention.

[0015] Figure 2 is omitted Figure 1 The second housing shown represents a plan view of the pump body.

[0016] Figure 3 It is a longitudinal sectional view of a control valve of a variable displacement oil pump according to the present invention.

[0017] Figure 4 yes Figure 1 An enlarged view of the main part.

[0018] Figure 5 yes Figure 3 AA line section view.

[0019] Figure 6 The drawings are for explaining a method for manufacturing a variable displacement oil pump according to the present invention, wherein (a) is a schematic diagram for explaining a coil spring arrangement step, and (b) is a cross-sectional view taken along line BB of (a).

[0020] Figure 7 1 is a diagram showing an operating state of the variable displacement oil pump of the present invention, and is a diagram showing an operating state in which the eccentricity of the cam ring is maximum.

[0021] Figure 8 1 is a diagram showing an operating state of the variable displacement oil pump of the present invention, and is a diagram showing an operating state in which the eccentricity of the cam ring is minimized. DETAILED DESCRIPTION

[0022] Hereinafter, an embodiment of the variable capacity oil pump of the present invention will be described in detail based on the accompanying drawings. It should be noted that in the following embodiment, an example of an oil pump in which the variable capacity oil pump is applied to supply lubricating oil to an internal combustion engine for an automobile is shown. In addition, in the following description, for convenience, the direction along the rotation axis of the drive shaft 2 is defined as "axial direction", the direction orthogonal to the rotation axis of the drive shaft 2 is defined as "radial direction", and the rotation direction of the drive shaft 2 is defined as "circumferential direction" for description.

[0023] (Structure of oil pump)

[0024] Figure 1 1 is an exploded perspective view of a pump body PA of the variable displacement oil pump according to the present embodiment. Figure 2 It means that Figure 1 The pump body PA is shown in a plan view with the second housing 12 removed.

[0025] like Figure 1As shown, the variable displacement oil pump includes a pump body PA and a control valve SV (see Figure 3 ). The pump body PA includes a drive shaft 2, a pump assembly 3 driven and rotated by the drive shaft 2, a cam ring 4 provided on the outer peripheral side of the pump assembly 3 in a swingable manner, and a coil spring SP urging the cam ring 4, which are housed inside the housing 1. It should be noted that in the present embodiment, the pump body PA is fastened to the engine (not shown), more specifically, to the side of the cylinder block (not shown), by bolts (not shown).

[0026] like Figure 1 , Figure 2 As shown, the housing 1 has a cup-shaped first housing 11 corresponding to a pump body and a second housing 12 corresponding to a cover member, the cover member being joined to the first housing 11 and blocking the opening of the first housing 11. The first housing 11 and the second housing 12 are fastened by a screw member SW in a state where they are positioned by a positioning pin PN. It should be noted that the first housing 11 and the second housing 12 are both formed integrally of a metal material, such as an aluminum alloy.

[0027] 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, one end side of the first housing 11 that is opposite to the second housing 12 in the axial direction is open, and the other end side is closed by the bottom wall 111. In other words, a cup-shaped pump housing portion 110 is defined inside the first housing 11 by the bottom wall 111 and the peripheral wall 112.

[0028] In addition, a joint surface 113 for joining with the second housing 12 is provided at the opening edge of one axial end side of the first housing 11. The joint surface 113 is provided in a manner extending radially outward of the first housing 11 and is formed integrally with the peripheral wall 112. In addition, a plurality of (two in this embodiment) internal threaded holes 113a are formed on the joint surface 113. The plurality of internal threaded holes 113a are provided at intervals in the circumferential direction, and a plurality of screws SW for fastening the second housing 12 to the first housing 11 are screwed into each of the internal threaded holes 113a. In addition, a plurality of (four in this embodiment) first housing side mounting holes 113b are formed on the joint surface 113. The plurality of first housing side mounting holes 113b are provided at intervals in the circumferential direction, and together with the second housing side mounting holes 121b provided in the second housing 12, constitute a pump mounting hole for mounting a variable capacity oil pump on a cylinder block not shown.

[0029] In addition, a first bearing hole (not shown) for supporting one end of the drive shaft 2 in a rotatable manner 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 suction passage 114 having a substantially arc shape is formed on the inner side surface of the bottom wall 111, on the outer peripheral side of the aforementioned first bearing hole (not shown) so as to open to a region (hereinafter referred to as "suction region") where the volume of the plurality of pump chambers 30 described later is expanded due to the pump action of the pump assembly 3. On the other hand, a first discharge passage 115 having a substantially arc shape is formed on the side opposite to the suction region across the rotation center Z of the drive shaft 2 so as to open to a region (hereinafter referred to as "discharge region") where the volume of the plurality of pump chambers 30 described later is reduced. In addition, a first pin support groove 111b is formed on the inner side surface of the bottom wall 111, on the outer peripheral side of the first discharge passage 115, so as to support the cam ring 4 in a swingable manner via a substantially cylindrical pivot pin 40. One axial end portion of the pivot pin 40 is press-fitted into the first pin support groove 111 b .

[0030] The first suction channel 114 is formed such that, in the rotation direction D of the drive shaft 2, the first end side is narrowest and the middle part is widest, and the channel gradually narrows from the middle part to the end part. In addition, a suction channel extension part 114a extending radially outward is continuously provided in the middle part of the first suction channel 114. Moreover, a suction port 114b (see FIG. 1 ) penetrating the bottom wall 111 and opening to the outside is provided in the suction channel extension part 114a. Figure 5 ), and the oil accumulated in the oil pan (not shown) is introduced through the suction port 124a. It should be noted that the suction port 114b can be directly opened to the aforementioned oil pan (not shown) through an unillustrated filter, and can also be connected to the aforementioned oil pan (not shown) through an unillustrated suction passage.

[0031] According to this structure, in the variable displacement oil pump, Figure 1 , Figure 2 As shown, the oil accumulated in the oil pan (not shown) is sucked into each pump chamber 30 located in the suction area through the suction port 114b, the first suction channel 114, and the second suction channel 124 described later, based on the negative pressure generated by the pump action of the pump assembly 3. In this way, in the variable displacement oil pump of this embodiment, the suction port 114b, the first suction channel 114, and the second suction channel 124 described later constitute a suction part.

[0032] like Figure 2 As shown, the first discharge channel 115 is formed to gradually expand from the starting end side toward the middle part and gradually decrease from the middle part toward the end side in the rotation direction D of the drive shaft 2. In addition, the first discharge channel 115 is provided with a discharge port (not shown) that penetrates the bottom wall 111 and opens to the outside.

[0033] According to this structure, in the variable displacement oil pump, Figure 1 , Figure 2 As shown, the oil that is pressurized by the pump action of the pump assembly 3 and discharged to the first discharge passage 115 and the second discharge passage 125 described later is supplied from the aforementioned discharge port (not shown) through the main oil gallery provided inside the aforementioned cylinder block (not shown) to the aforementioned sliding parts (such as crankshaft metal), the aforementioned oil injection device (not shown) for cooling the piston of the aforementioned engine (not shown), and the aforementioned valve timing control device (not shown). In this way, in the variable displacement oil pump of the present embodiment, the first discharge passage 115, the later described second discharge passage 125, and the aforementioned ejection port (not shown) constitute a discharge portion.

[0034] In addition, a connecting groove (not shown) is provided on the bottom wall 111 of the first housing 11, which connects the first discharge passage 115 and the first bearing hole (not shown). That is, oil is supplied to the first bearing hole (not shown) through the connecting groove, and oil is supplied to the side of the rotor 31 and each blade 32 described later, thereby ensuring good lubrication of each sliding part. It should be noted that the connecting groove is formed to be inconsistent with the direction in which each blade 32 described later emerges and disappears, so as to prevent each blade 32 from falling into the connecting groove.

[0035] In addition, on the inner side of the peripheral wall 112 constituting the side wall of the pump housing portion 110, with respect to a straight line M connecting the center Z of the first bearing hole 111a, which is the rotation center of the drive shaft 2, and the center Q of the first pin support groove 111b, which is the swing center of the cam ring 4 (hereinafter referred to as a "cam ring reference line"), Figure 2 The first sealing sliding surface 112a and the second sealing sliding surface 112b, which are arranged on the outer peripheral side of the cam ring 4 and can slide in contact with the first sealing component S1 and the second sealing component S2, are formed on the upper side. The first sealing sliding surface 112a is formed into an arc surface with a curvature formed by a first radius R1 from the center Q of the first pin support groove 111b, and is set to a circumferential length within the swing range of the cam ring 4 that the first sealing component S1 can slide in contact with. Similarly, the second sealing sliding surface 112b is formed into an arc surface with a curvature formed by a second radius R2 from the center Q of the first pin support groove 111b, and is set to a circumferential length within the swing range of the cam ring 4 that the second sealing component S2 can slide in contact with.

[0036] In addition, relative to the cam ring reference line M, Figure 2 A third sealing sliding surface 112c is formed on the lower side of the cam ring 4 on the outer peripheral side thereof, with which the third sealing member S3 can slidably contact. The third sealing sliding surface 112c is formed in the shape of an arc surface having a curvature formed by a third radius R3 from the center Q of the first pin support groove 111b, and is set to a circumferential length within the swing range of the cam ring 4 with which the third sealing member S3 can slidably contact.

[0037] like Figure 1 As shown, the second housing 12 functions as a cover member that blocks the opening portion (pump housing portion 110) of the first housing 11, and is joined to the joint surface 113 of the first housing 11 via a screw SW. Specifically, the second housing 12 has a screw through hole 121a provided at a position corresponding to the internal threaded hole 113a of the first housing 11. And, the screw SW that penetrates the screw through hole 121a is screwed into the internal threaded hole 113a of the first housing 11, so that the second housing 12 is fastened to the first housing 11.

[0038] In addition, in the second housing 12, a second bearing hole 122a is formed through-formed at a position opposite to the first bearing hole 111a of the first housing 11, and supports the other end side of the drive shaft 2 in a manner that the other end side can rotate. In addition, a second suction channel 124 and a second discharge channel 125 corresponding to the first suction channel 114 and the first discharge channel 115 are also arranged on the inner side surface of the second housing 12, opposite to the first suction channel 114 and the first discharge channel 115 of the first housing 11. Moreover, on the inner side surface of the second housing 12, a second pin support groove 122b is formed at a position opposite to the first pin support groove 111b. The second pin support groove 122b presses and holds the other axial end of the pivot pin 40, and supports the pivot pin 40 together with the first pin support groove 111b.

[0039] 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 the first bearing hole 111a of the first housing 11. On the other hand, a large-diameter drive shaft portion 22 of the drive shaft 2 on the other end side in the axial direction and having an outer diameter larger than that of the general drive shaft portion 21 is rotatably supported in the second bearing hole 122a of the second housing 12. Moreover, a drive shaft end portion 23 of the drive shaft 2 formed with a relatively smaller diameter at the other end side than the large-diameter drive shaft portion 22 faces outward through the first bearing hole 111a 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 aforementioned 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.

[0040] like Figure 1 , Figure 2As shown, the pump assembly 3 includes a substantially cylindrical rotor 31 which is housed on the inner circumference of the cam ring 4 and is driven and rotated by the drive shaft 2, and a plurality of blades 32 which are housed in a plurality of slits 312 which are radially opened to the outer circumference of the rotor 31 so as to be able to appear and disappear. In addition, a pair of ring members 33, 33 which are formed to have a smaller diameter than the rotor 31 and are housed 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.

[0041] The rotor 31 has a substantially circular shaft through hole 311 that penetrates the center portion in the axial direction and through which the drive shaft general portion 21 passes. In addition, the rotor 31 has a plurality of slits 312 that are cut radially from the center side of the shaft through hole 311 toward the radial outside. In addition, a back pressure chamber 313 with a substantially circular cross section for introducing oil is provided at the bottom of each slit 312. That is, each blade 32 is configured 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.

[0042] In addition, the plurality of blades 32 housed in the rotor 31 are formed into a rectangular plate shape from a predetermined metal material, and the top end surfaces of the plurality of blades 32 are in sliding contact with the inner peripheral surface of the cam ring 4 (the peripheral wall of the pump assembly housing portion 41 described later) as the rotor 31 rotates. That is, the top end surfaces of the blades 32 are in sliding contact with the inner peripheral surface of the cam ring 4, so that the rotor 31, the 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, the blades 32 are configured so that the base end surfaces of the blades 32 are in sliding contact with the outer peripheral surfaces of the pair of ring members 33, 33 as the rotor 31 rotates, and the blades 32 are pushed outward in the radial direction of the rotor 31 by the pair of ring members 33, 33. Thus, even when the engine speed is low and the centrifugal force and the oil pressure in the back pressure chamber 313 caused by the rotation of the rotor 31 are low, the top end surfaces of the blades 32 are in sliding contact with the inner peripheral surface of the cam ring 4, thereby separating the pump chambers 30 in a liquid-tight manner.

[0043] 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 circular arc groove-shaped swing support portion 42 capable of slidingly contacting the outer circumferential surface of the cylindrical pivot pin 40 supported by the housing 1 is provided along the axial direction on the outer circumference of the cam ring 4. That is, the cam ring 4 is supported in a swingable manner inside the pump housing portion 110 via the pivot pin 40 by slidingly contacting the outer circumferential surface 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.

[0044] 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 surface 112a, the second sealing sliding surface 112b, and the third sealing sliding 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 surface 112a. The second sealing structure 432 has a second sealing surface 432a which is concentric with the second sealing sliding surface 112b. The third sealing structure 433 has a third sealing surface 433a which is concentric with the third sealing sliding surface 112c.

[0045] In addition, a first seal retaining groove 431b extending in the axial direction is formed on the first sealing surface 431a so as to open toward the first sealing sliding surface 112a. A second seal retaining groove 432b extending in the axial direction is formed on the second sealing surface 432a so as to open toward the second sealing sliding surface 112b. A third seal retaining groove 433b extending in the axial direction is formed on the third sealing surface 433a so as to open toward the third sealing sliding surface 112c.

[0046] Furthermore, the first seal retaining groove 431b contains a first seal member S1 that comes into sliding contact with the first seal sliding surface 112a when the cam ring 4 swings. The second seal retaining groove 432b contains a second seal member S2 that comes into sliding contact with the second seal sliding surface 112b when the cam ring 4 swings. The third seal retaining groove 433b contains a third seal member S3 that comes into sliding contact with the third seal sliding surface 112c when the cam ring 4 swings.

[0047] like Figure 1 , Figure 4 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 4 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 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 surfaces 112a, 112b, and 112c in a liquid-tight manner.

[0048] In addition, according to the above-mentioned structure, on the outer peripheral side of the cam ring 4, the first control oil chamber PR1 is defined by the first sealing member S1 that is in sliding contact with the first sealing sliding surface 112a and the second sealing member S2 that is in sliding contact with the second sealing sliding surface 112b. The first control oil pressure P1 is introduced into the first control oil chamber PR1 through the first passage L1, one of which is branched in two from the discharge pressure introduction passage Lb connected to the main oil passage. In addition, 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 passage. In addition, the first passage L1 is connected to the first control pressure introduction hole 118 that passes through 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. Furthermore, the first control oil pressure P1 introduced into the first control oil chamber PR1 acts on the first pressure-receiving surface 441 formed between the first sealing structure 431 and the second sealing structure 432 in the outer peripheral surface of the cam ring 4 facing the first control oil chamber PR1. The oil pressure acting on the first pressure-receiving surface 441 applies a moving force (swinging force) to the cam ring 4 in a direction (hereinafter referred to as "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.

[0049] Similarly, on the outer peripheral side of the cam ring 4, the second control oil chamber PR2 is defined by the swing support portion 42 that is in sliding contact with the pivot pin 40 and the second sealing member S2 that is in sliding contact with the second sealing sliding surface 112b. For the second control oil chamber PR2, the second passage L2, which is the other one branched from the discharge pressure introduction passage Lb, introduces the second control oil pressure P2 that is reduced in pressure by the control valve SV. In addition, the second passage L2 introduces the second control oil pressure P2 into the second control oil chamber PR2 via a second control pressure introduction hole (not shown) that passes through the second housing 12. And, the second control oil pressure P2 introduced into the second control oil chamber PR2 acts on the second pressure receiving surface 442 formed between the swing support portion 42 and the third sealing structure portion 433 in the outer peripheral surface of the cam ring 4 facing the second control oil chamber PR2. Through the oil pressure acting on the second pressure-bearing surface 442, a moving force (swinging force) is applied to the cam ring 4 in a direction in which the eccentricity (the eccentricity of the center O of the pump assembly housing 41 relative to the rotation center Z of the drive shaft 2) Δ of the cam ring 4 increases (hereinafter referred to as the "eccentricity direction").

[0050] The coil spring SP is accommodated in a spring housing portion 119 provided at a position opposite to the pivot pin 40 across the rotation center Z of the drive shaft 2. That is, in the spring housing portion 119, the coil spring SP compressed by a predetermined preload (set load W1) is loaded between the arm portion 45 extending toward the outer peripheral side of the cam ring 4 and one end wall 119a of the spring housing portion 119. Here, the spring housing portion 119 is formed in the first housing 11 in such a manner that the peripheral wall 112 of the pump housing portion 110 is recessed toward the radially outer side on the outer peripheral side of the first suction passage 114. In addition, the one end wall 119a of the spring housing portion 119 functions as a seating surface for the coil spring SP, and on the other hand, the other end wall 119b of the spring housing portion 119 functions as a stopper for limiting the range of movement of the cam ring 4 in the eccentric direction. That is, the cam ring 4 is always urged in the eccentric direction by the coil spring SP, and is configured to maintain the maximum eccentric state by the arm portion 45 abutting against the other end wall 119 b of the spring housing portion 119 .

[0051] According to the above structure, when the force based on the internal pressure of the first control oil chamber PR1 (the first control oil pressure P1) is smaller than the set load W1 of the coil spring SP, the cam ring 4 moves in the eccentric direction based on the set load W1 of the coil spring SP, and becomes, for example Figure 2 On the other hand, when the discharge pressure P increases and the force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1) exceeds the set load W1 of the coil spring SP, the cam ring 4 moves in the concentric direction according to the discharge pressure P.

[0052] (Control valve structure)

[0053] Figure 3 1 is a longitudinal sectional view of a control valve SV for controlling the discharge amount (discharge pressure) of the variable displacement oil pump (pump body PA) according to the present embodiment.

[0054] like Figure 3 As shown, the control valve SV is an electromagnetic valve driven and controlled by a control device (not shown) in charge of engine control. Specifically, the control valve SV includes 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 an excitation current output by the control device (not shown).

[0055] The valve portion 5 is a so-called three-way valve including a valve housing 51, a spool valve core 52, a retaining member 53, and a valve spring 54. It should be noted that the valve portion 5 may be integrally provided with the variable displacement oil pump in the form of being built into the housing 1, or may be separately provided with the variable displacement oil pump.

[0056] The valve housing 51 is formed of a metal material, such as an aluminum alloy material, into a substantially 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 having 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. In addition, 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 discharge passage Pd for discharging oil from the spring housing chamber 55 described later, and opens to the discharge passage Ld. Here, the discharge passage Pd may not open to the discharge passage Ld but directly open to the oil pan (not shown) corresponding to the low pressure part. In addition, the discharge passage Pd only needs to be connected to the low pressure part. In addition to the structure of connecting to the oil pan (not shown) corresponding to the atmospheric pressure, for example, it may be configured to connect to the vicinity of the suction port 114b which becomes a negative pressure. It should be noted that, in the following, for the sake of convenience, the first valve core sliding contact part 511 side ( Figure 3 The end portion on the right side of the second valve core sliding contact portion 512 ( Figure 3 The end portion (on the left side in FIG. 1 ) is defined as the second end portion for explanation.

[0057] 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 passage Pc for supplying and discharging oil (second control oil pressure P2) with respect to the second control oil chamber PR2 through the second passage L2.

[0058] In addition, similarly, a second annular groove 514 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 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. In addition, the second valve hole 514a is composed of a circular hole that is substantially circular in a plan view, and functions as an introduction passage Pb for introducing oil (discharge pressure P) from the discharge pressure introduction passage Lb.

[0059] The spool valve core 52 is a cylindrical shape formed in a stepped shape with different outer diameters in the central axis Y direction as the moving direction, 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 portions 521 and second boss portions 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.

[0060] 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 second valve hole 514a. 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 second valve hole 514a into the relay chamber Rc acts on the second pressure-receiving surface Pf2 that is relatively larger than the first pressure-receiving surface Pf1, so that the spool valve element 52 is pushed toward the second end side.

[0061] 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 housing portion 510 in the radial direction of the valve housing 51. The back pressure chamber Rb collects 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 housing portion 510). In addition, the back pressure chamber Rb is connected to the spring housing 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 and the spring housing chamber 55 described later. That is, the oil collected in the back pressure chamber Rb is guided to the spring housing chamber 55 described later through the discharge hole 525 and the internal passage 526, and is discharged to an oil pan not shown in the figure through the discharge passage Pd and the discharge passage Ld.

[0062] In addition, the slide valve core 52 has a spring support portion 527 that supports the first end of the valve spring 54 that is opposite to the slide valve core 52 at the end 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 of the valve spring 54 with the spring surrounding portion 527a, and supports the first end of the valve spring 54 with the spring supporting surface 527b.

[0063] The retaining member 53 has an annular spring seat portion 531 supporting the second end of the valve spring 54 and a circular stopper opening portion 530 penetrating the center position of the spring seat portion 531. That is, the outer peripheral edge portion of the retaining member 53 is embedded in the opening end portion on the second end side of the valve housing 51, the spring seat portion 531 supports the second end of the valve spring 54, and the stopper opening portion 530 connects the second valve hole 514a and the discharge passage Pd.

[0064] 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.

[0065] The solenoid part 6 includes a cylindrical housing 61, a coil and an armature (not shown) housed in the housing 61, and a rod 62 fixed to the armature and provided so as to be movable forward and backward along the central axis Y direction together with the armature. In addition, an excitation current is supplied to the solenoid part 6 from a control device (not shown) based on the operating state of the engine detected or calculated by using predetermined parameters such as the oil temperature, water temperature, and engine speed of the engine (not shown). Furthermore, the solenoid part 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.

[0066] (Restriction structure of the coil spring at the arm)

[0067] Figure 4 It means that it will be stored in Figure 1 The vicinity of the coil spring SP of the spring housing portion 119 is shown in an enlarged manner. Figure 1 In addition, Figure 5 It means along Figure 3 When the AA line is cut Figure 3 AA line section view.

[0068] like Figure 4 , Figure 5As shown, in the area on the outer peripheral side of the pump housing 110 of the first housing 11 and the outer peripheral side of the first suction passage 114, a substantially rectangular concave spring housing 119 is formed in the form of a tangential direction along the outer peripheral edge of the pump housing 110 so as to be open to the joint surface 113 of the first housing 11. In addition, in the spring housing 119, a coil spring SP for urging the cam ring 4 in an eccentric direction is housed between the arm 45 and the spring housing 119 in a state compressed by a predetermined amount and with a predetermined preload (set load W1) so as to face the arm 45 of the cam ring 4 housed in the pump housing 110.

[0069] The spring receiving portion 119 is substantially rectangular in plan view and is set to a depth such that the center X of the coil spring SP is located substantially in the center of the axial width (width in the Z-axis direction) of the cam ring 4. Figure 5 As shown, in a state where the coil spring SP is accommodated in the spring accommodation portion 119 , a predetermined gap C1 is formed between the second housing 12 (the joining surface of the first housing 11 ) and the coil spring SP.

[0070] The spring housing portion 119 includes an end wall 119a formed on one end side in the X-axis direction that contacts the arm portion 45 of the cam ring 4, and another end wall 119b disposed opposite to the end wall 119a and formed on the other end side in the X-axis direction that contacts the coil spring SP. The end wall 119a contacts the arm portion 45 of the cam ring 4 to limit the maximum eccentricity of the cam ring 4. On the other hand, the other end wall 119b contacts the coil spring SP to support the coil spring SP.

[0071] In addition, the spring receiving portion 119 has an outer limiting wall 119c equivalent to a first limiting wall, which can support the outer side of the coil spring SP and limit the positional displacement of the coil spring SP to the radial outside. On the other hand, the spring receiving portion 119 has an inner limiting wall 119d that can limit the positional displacement of the coil spring SP to the radial inside with respect to the end of the other end wall 119b side of the coil spring SP on the side opposite to the outer limiting wall 119c across the X-axis that is the center of the outer diameter of the coil spring SP. In addition, the spring receiving portion 119 has a bottom limiting wall 119e equivalent to a third limiting wall on the side opposite to the protrusion 46 across the X-axis, which is formed by the bottom wall of the spring receiving portion 119 and can limit the positional displacement of the coil spring SP to the side opposite to the protrusion 46 in the axial direction of the coil spring SP.

[0072] In addition, the arm portion 45 of the cam ring 4 is provided with a protrusion 46 extending from a spring abutting surface 451 that abuts against the coil spring SP in the longitudinal direction (X-axis direction) of the coil spring SP and overlapping a portion of the outer circumference of the coil spring SP at the end portion on the side of the joint surface 113 of the first housing 11. The protrusion 46 is formed integrally with the arm portion 45 and has a substantially rectangular cross-section. The protrusion 46 is not an annular shape that covers the entire circumference of the end portion on the arm portion 45 side of the coil spring SP, but is formed so as to overlap only a portion of the circumferential region of the end portion on the arm portion 45 side of the coil spring SP. In addition, the protrusion 46 is provided in a manner separated from the coil spring SP disposed on the inner side, and is configured to form a small gap C2 with the coil spring SP in an upright state.

[0073] Here, the projection 46 is preferably provided at a side where the coil spring SP is easily tilted by the flow of oil, that is, at a position downstream of the coil spring SP in the flow of oil introduced from the suction port 114b. In the case of this embodiment, the projection 46 is preferably arranged at a position corresponding to the flow of oil introduced from the suction port 114b (refer to Figure 5 The projection 46 is an end portion of the arm portion 45 on the side of the engagement surface 113 of the first housing 11 on the downstream side of the arrow F). In other words, the projection 46 can be arranged at any position that can restrict the tilting of the coil spring SP, depending on the occurrence of the tilting of the coil spring SP. In addition, as described above, when the projection 46 is provided at the end portion on the side of the engagement surface 113 of the first housing 11, the projection 46 is preferably provided at a position overlapping with the center (X axis) of the outer diameter of the coil spring SP. Moreover, in the present embodiment, a method of configuring a single projection 46 is illustrated, but a plurality of projections 46 may be arranged as needed, for example, depending on the occurrence of the tilting of the coil spring SP.

[0074] In addition, a cam ring limiting wall 47 corresponding to a second limiting wall is formed on the outer peripheral side of the cam ring 4. Figure 4 The flat surface shape substantially parallel to the outer restricting wall 119 c of the first housing 11 in the maximum eccentric state of the cam ring 4 shown can support the outer portion of the coil spring SP and restrict radial inward positional displacement of the coil spring SP.

[0075] (How to assemble the coil spring)

[0076] Figure 6 The drawings illustrate a method for manufacturing a variable displacement oil pump according to the present embodiment, wherein (a) is a schematic diagram for illustrating a coil spring arrangement step, and (b) is a cross-sectional view taken along line BB of (a).

[0077] When assembling the spiral spring SP, Figure 6As shown in (a), first, the coil spring SP is compressed by the clamp 7. The clamp 7 is provided with a pair of spring holding parts on a connection base 70 formed in a rectangular plate shape, and the pair of spring holding parts are configured such that a first holding part 71 formed in a bifurcated shape (U-shaped in a plan view) via a cutout 710 and a second flat holding part 72 arranged in a parallel and opposed manner with respect to the first holding part 71 can move relative to each other, and the coil spring SP is compressed by sandwiching the coil spring SP between the first holding part 71 and the second holding part 72 and making the interval Cx between the first holding part 71 and the second holding part 72 narrower than the free length of the coil spring SP.

[0078] Next, in a state where the cam ring 4 is housed in the pump housing 110 of the first housing 11, the coil spring SP compressed by the jig 7 is inserted between the other end wall 119b of the spring housing 119 and the arm 45 (see Figure 6 Specifically, if Figure 6 As shown in (a)(b), while the coil spring SP is held in a compressed state between the first retaining portion 71 and the second retaining portion 72 of the clamp 7, the protrusion 46 of the cam ring 4 is avoided through the cutout 710 of the clamp 7, and the clamp 7 is inserted between the other end wall 119b of the spring storage portion 119 and the arm portion 45 from the side of the mating surface 113 of the first housing 11.

[0079] Thereafter, the coil spring SP held in a compressed state between the first holding portion 71 and the second holding portion 72 of the clamp 7 is pushed out in the direction indicated by the arrow between the other end wall 119b of the spring receiving portion 119 and the arm portion 45 by a push-out mechanism (not shown) provided in the clamp 7 (see FIG. Figure 6 The pushed-out coil spring SP is then stretched due to the restoring force based on the compression, and one end elastically abuts against the spring abutment surface 451 of the arm portion 45, and the other end elastically abuts against the other end wall 119b of the spring receiving portion 119, thereby completing the assembly of the coil spring SP (refer to Figure 6 below (a).

[0080] (Oil pump working instructions)

[0081] Next, based on Figure 7 , Figure 8 The operation of the variable displacement oil pump according to the present embodiment will be described. Figure 7 The variable displacement oil pump has an operating state in which the eccentricity of the cam ring 4 is the largest among the operating states of the variable displacement oil pump. Figure 8 The figure shows an operating state in which the eccentricity of the cam ring 4 is the smallest among the operating states of the variable displacement oil pump.

[0082] like Figure 7 , Figure 8As shown, in the variable displacement oil pump of the present embodiment, the rotation of the 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, oil is sucked up from the oil pan (not shown) via the suction port 114b, the first suction channel 114, and the second suction channel 124. In addition, at the same time as the suction action, the oil in each pump chamber 30 located in the discharge area is discharged to the discharge passage (not shown) via the first discharge channel 115, the second discharge channel 125, and the discharge port 115a. And, the oil discharged to the discharge passage is pressure-sent to the sliding part (such as crankshaft metal) of the engine (not shown), the oil injection device (not shown), and the valve timing control device (not shown) via the main oil gallery, and is guided to the first passage L1 and the second passage L2 via the discharge pressure introduction passage Lb connected to the main oil gallery. It should be noted that a hydraulic pressure sensor (not shown) capable of detecting a discharge pressure P is disposed in the main oil gallery, and the detection result of the hydraulic pressure sensor is fed back to a control device (not shown).

[0083] In addition, the cam ring 4 swings with the pivot pin 40 as a fulcrum, and the difference between the rotation center Z of the drive shaft 2 and the center O of the pump unit storage portion 41, that is, the eccentricity Δ (see Figure 2 ) changes, 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. On the other hand, 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 concentric force based on the internal pressure of the first control oil chamber PR1 (first control oil pressure P1), the set load W1 of the coil spring SP, and the eccentric force of the internal pressure of the second control oil chamber PR2 (second control oil pressure P2).

[0084] Specifically, from the start of the internal combustion engine to the predetermined speed, the first control oil pressure P1 is introduced into the first control oil chamber PR1 via the first passage L1 branched from the discharge pressure introduction passage Lb. In addition, in the control valve SV, the force (oil pressure Fp2) generated by the discharge pressure P introduced via the second passage L2 branched from the discharge pressure introduction passage Lb acting on the second pressure receiving surface Pf2 of the spool valve core 82 is smaller than the set load W2 of the valve spring 54. Therefore, as Figure 7As shown, the spool valve core 82 is maintained in a state of maximum displacement toward the first end side, the introduction passage Pb and the supply and discharge passage Pc are connected (first state), and the second control oil pressure P2 is introduced into the second control oil chamber PR2. As a result, the 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.

[0085] Soon after, when the predetermined speed is reached and the discharge pressure P reaches the predetermined internal combustion engine required oil pressure, the oil pressure Po of the discharge pressure P becomes larger than the set load W2 of the valve spring 54 when the duty ratio of the excitation current supplied to the solenoid portion 6 is 0%. Figure 8 As shown, the spool valve core 52 moves toward the second end side, cuts off the communication between the introduction passage Pb and the supply and discharge passage Pc, and the supply and discharge passage Pc is connected to the discharge passage Pd (second state), and 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 oil pressure Fp1 generated by the first control oil pressure P1 acting on the first pressure receiving surface 441 exceeds the set load W1 of the coil spring SP, and with the increase of the discharge pressure P, the eccentricity Δ of the cam ring 4 decreases to the minimum eccentricity state, and the discharge pressure P is maintained at the internal combustion engine required oil pressure.

[0086] That is, in the variable displacement oil pump, the movement of the slide valve core 52 toward the second end side based on the increase of the 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 state in which the supply and discharge passage Pc is connected to the introduction passage Pb and the state in which the supply and discharge passage Pc is connected to the discharge passage Pd are alternately and continuously switched, so that the discharge pressure P is maintained at the required oil pressure of the internal combustion engine.

[0087] It should be noted that, in the present embodiment, the working state of the variable capacity oil pump is illustrated when the internal combustion engine is started and the discharge pressure P becomes a high pressure state. However, in the variable capacity oil pump, even when the oil pressure Po of the discharge pressure P is smaller than the set load W2 of the valve spring 54, by adjusting the duty cycle of the excitation current supplied to the solenoid portion 6 of the control valve SV, it is possible to transition to the second state at any time based on the electromagnetic force Fm of the solenoid portion 6, and the discharge pressure P of the variable capacity oil pump can be controlled in multiple stages.

[0088] (Effects of this embodiment)

[0089] As mentioned above, in the conventional variable displacement oil pump, the coil spring is fitted into the outer peripheral side of the protrusion protruding from the spring contact surface of the arm portion of the cam ring. Therefore, when assembling the coil spring, the compressed coil spring must be restored and the protrusion must be fitted into the inner peripheral side of the coil spring, making the assembly of the coil spring difficult. There is room for improvement in this regard.

[0090] In addition, as another means of suppressing the positional deviation of the coil spring, the following scheme is also considered: a substantially cylindrical protrusion or recess surrounding the outer peripheral side of the coil spring is provided on the spring contact surface of the arm portion of the cam ring, and the coil spring is fitted into the inner peripheral side of the protrusion or recess, thereby suppressing the positional deviation of the coil spring by supporting the outer peripheral side of the coil spring with the protrusion or recess. However, in this case, when assembling the coil spring, the compressed coil spring must be restored and fitted into the inner peripheral side of the protrusion or recess, which is the same as the scheme of fitting the coil spring into the outer peripheral side of the protrusion, and there is room for improvement in this regard.

[0091] Here, the difficulty of assembling the above-mentioned coil spring is specifically described. In the case where the coil spring is fitted on the outer peripheral side of the protrusion and in the case where the coil spring is fitted on the inner peripheral side of the protrusion or the recess, a jig for assembling the coil spring in a compressed state is used to preload the coil spring. The jig is assembled in the following manner: in a state where the coil spring is sandwiched and compressed between a pair of holding parts arranged opposite to each other, the coil spring is inserted between the arm of the cam ring and the housing (spring storage part) together with the pair of holding parts, and the coil spring is pushed out from the pair of holding parts, thereby pushing the coil spring between the arm of the cam ring and the housing (spring storage part).

[0092] In this case, the coil spring needs to be additionally compressed by the thickness of a pair of retaining parts inserted between the arm of the cam ring and the housing (spring housing) together with the coil spring. Therefore, the restoring force of the coil spring increases in accordance with the amount of the additional compression, and when the coil spring is pushed out of the clamp, the coil spring is released with a greater restoring force, and the coil spring abuts against the arm of the cam ring and the housing (spring housing) more forcefully. As a result, the arm of the cam ring and the housing (spring housing) may be damaged by the abutment of the coil spring.

[0093] Furthermore, since the coil spring is released by pushing it out of the clamp, it is difficult to control the posture of the coil spring after it is pushed out of the clamp. Therefore, it is very difficult to fit the coil spring into the outer circumference or inner circumference of the protrusion whose gap with the coil spring is set narrower as described above, which obviously deteriorates the assembly workability of the coil spring. In addition, since it is difficult to control the posture of the coil spring after it is released from the clamp, it may also cause poor assembly of the coil spring, such as assembling the coil spring in a tilted state.

[0094] In addition, as an alternative to the scheme of fitting the coil spring to the outer peripheral side of the protrusion, the following scheme is considered: the protrusion is formed separately from the cam ring as a so-called retaining member, and the coil spring is assembled in a state where the retaining member is pre-fitted to the inner peripheral side of the coil spring. According to this scheme, the deterioration of the assembly workability of the coil spring can be avoided, but the number of parts of the variable capacity oil pump will increase due to the separate formation of the protrusion as a retaining member. As a result, the manufacturing cost, management man-hours, and assembly man-hours of the retaining member increase, which will increase the manufacturing cost of the variable capacity oil pump.

[0095] In contrast, the variable capacity oil pump of the present embodiment comprises: a housing 1 (first housing 11) having a pump housing portion 110; a cam ring 4 housed inside the pump housing portion 110 in a movable manner; a pump assembly 3 housed on the inner circumference of the cam ring 4 in a rotatable manner and forming a plurality of pump chambers 30 together with the cam ring 4; a coil spring SP disposed in the pump housing portion 110 and applying force in a direction in which the eccentricity of the cam ring 4 increases relative to the rotation axis of the pump assembly 3; and a protrusion 46 provided on the cam ring 4 and partially formed in a manner that extends from a spring abutment surface 451 abutted by the coil spring SP in the longitudinal direction of the coil spring SP and overlaps a portion of the outer circumference of the coil spring SP.

[0096] Thus, in the variable displacement oil pump of the present embodiment, the protrusion 46 partially formed so as to overlap a part of the outer periphery of the coil spring SP is provided on the spring contact surface 451 of the cam ring 4, and thus the inclination of the coil spring SP can be restricted by the protrusion 46. Thus, the upright state of the coil spring SP can be maintained and an appropriate force can be applied to the cam ring 4 (arm portion 45).

[0097] Moreover, since the protrusion 46 is partially formed in a manner overlapping a portion of the outer circumference of the coil spring SP, when assembling the coil spring SP, it is sufficient to push the coil spring SP into the inner side of the protrusion 46, and there is no need to fit the coil spring SP into the protrusion or the recess as described above. Therefore, the assembly operation of the coil spring SP can be easily performed.

[0098] Moreover, the protrusion 46 is partially formed in a manner overlapping a part of the outer periphery of the coil spring SP, and compared with the case where the protrusion 46 is formed in a ring shape surrounding the outer periphery of the coil spring SP as described above, the assembled state of the coil spring SP can be visually confirmed from the outside. Thus, the quality of the assembled state of the coil spring SP can be easily determined by visual inspection, which contributes to efficient quality assurance of the oil pump.

[0099] Here, the following scheme may be considered: the protrusion 46 is arranged on the inner side surface of the second housing 12 that blocks the spring housing portion 119 instead of the cam ring 4. However, the inner side surface of the second housing 12 is finished by machining, so when the protrusion 46 is provided on the inner side surface of the second housing 12, it is necessary to process the inner side surface of the second housing 12 while avoiding the protrusion 46, which may lead to deterioration of productivity and increase of manufacturing cost for the variable displacement oil pump, so it is not suitable.

[0100] In addition, in the variable capacity oil pump of the present embodiment, the housing 1 (first housing 11) has a first limiting wall (outer limiting wall 119c) that limits the movement of the coil spring SP toward the radial outside that is perpendicular to the rotation axis Z of the pump assembly 3, and the cam ring 4 has a second limiting wall (cam ring limiting wall 47) that limits the movement of the coil spring SP toward the radial inside that is perpendicular to the rotation axis Z of the pump assembly 3.

[0101] Thus, in this embodiment, the positional deviation of the coil spring SP can be restricted by the outer restricting wall 119c, which is the first restricting wall provided in the spring housing portion 119 of the housing 1 (first housing 11), and the cam ring restricting wall 47, which is the second restricting wall provided in the cam ring 4. Thus, the occurrence of the tilting of the coil spring SP can be effectively suppressed together with the protrusion 46.

[0102] In addition, in the variable displacement oil pump of the present embodiment, a single protrusion 46 is provided.

[0103] Thus, in the present embodiment, by providing a single protrusion 46, when assembling the coil spring SP, by using, for example, the jig 7 in which the first holding portion 71 formed into a bifurcated shape by the cutout 710 and the second holding portion 72 in a flat shape are arranged opposite to each other, the coil spring SP can be assembled between the cam ring 4 (the spring contact surface 451 of the arm portion 45) and the housing 1 (the other end wall 119b of the spring housing portion 119 of the first housing 11) by avoiding the protrusion 46 by utilizing the cutout 710, while the coil spring SP is compressed and held between the first holding portion 71 and the second holding portion 72. Thus, the assembly workability of the coil spring SP can be improved.

[0104] In addition, the protrusion 46 is arranged in the middle of the flow of the oil introduced from the suction port 114b, so it may become a resistance to the flow of the oil. Therefore, by providing a single protrusion 46 as in the present embodiment, the flow resistance of the oil is reduced compared to the case where a plurality of protrusions 46 are provided, and the pressure loss of the pump caused by providing the protrusion 46 can be reduced.

[0105] Furthermore, in the variable displacement oil pump of the present embodiment, the protrusion 46 is provided at a position overlapping with the center X of the outer diameter of the coil spring SP.

[0106] Thus, in this embodiment, the protrusion 46 is provided at a position overlapping with the center X of the outer diameter of the coil spring SP, and the inclination of the coil spring SP can be balanced and appropriately restricted by the protrusion 46. In other words, even if the cam ring 4 swings, the protrusion 46 can appropriately restrict the movement of the coil spring SP.

[0107] In the variable displacement oil pump of the present embodiment, the housing 1 (first housing 11 ) includes the third restriction wall (cam ring restriction wall 47 ) that restricts movement of the coil spring SP to the side opposite to the protrusion 46 in the radial direction of the coil spring SP.

[0108] Thus, in the present embodiment, the cam ring limiting wall 47 is provided as a third limiting wall for limiting the movement of the coil spring SP to the radial direction of the coil spring SP opposite to the protrusion 46. Thus, the coil spring SP can be sandwiched between the protrusion 46 and the housing 1 (the cam ring limiting wall 47 of the spring housing portion 119 of the first housing 11), and the coil spring SP can be positioned more easily.

[0109] In the variable displacement oil pump of the present embodiment, the coil spring SP is disposed in the oil passage extending from the suction port 114 b provided in the housing 1 to the pump chamber 30 , and the projection 46 is disposed downstream of the coil spring SP in the oil passage.

[0110] Thus, in this embodiment, the projection 46 is arranged downstream of the coil spring SP in the oil passage from the suction port 114b to the suction side of the pump chamber 30. Thus, the occurrence of the tilting of the coil spring SP caused by the flow of oil flowing from the suction port 114b to the pump chamber 30 can be effectively suppressed.

[0111] In addition, the manufacturing method of the variable capacity oil pump of the present embodiment includes: a cam ring configuration step, in which the cam ring 4 is configured in the pump housing portion 110; and a coil spring configuration step, in which a coil spring SP is configured in the pump housing portion 110 after the cam ring configuration step, wherein the coil spring SP is held in a compressed state by a clamp 7, the clamp 7 having a two-pronged first retaining portion 71 with a cutout 710 in the middle portion and capable of retaining one end of the coil spring SP, and a second retaining portion 72 capable of retaining the other end of the coil spring SP, and the clamp 7 is inserted between the cam ring 4 and the pump housing portion 110 in a manner that avoids the protrusion 46 by utilizing the cutout 710 of the first retaining portion 71, thereby configuring the coil spring SP in the pump housing portion 110.

[0112] Thus, in the present embodiment, the coil spring SP is held in a compressed state by the clamp 7, and the clamp 7 has a two-pronged first retaining portion 71 and a second retaining portion 72 formed with a notch 710. The notch 710 is used to avoid the protrusion 46 and the coil spring SP is inserted between the cam ring 4 (the spring abutment surface 451 of the arm portion 45) and the pump housing portion 110 (the other end wall 119b of the spring housing portion 119), thereby assembling the coil spring SP. Therefore, compared with the structure in which the entire circumference of the coil spring SP is surrounded by a protrusion (or a recessed portion) as described above, since the notch 710 can be used to avoid the protrusion 46, there is no need to avoid the protrusion 46 by excessively compressing the coil spring as described above. Thus, as described above, Figure 6 As shown, the compression amount of the coil spring SP can be reduced by an amount corresponding to the height of the protrusion 46, and the rebound force (restoration force) of the coil spring SP when the coil spring SP is released from the clamp 7 can be reduced. As a result, when assembling the coil spring SP, it is possible to suppress assembly errors of the coil spring SP, such as assembling the coil spring SP in a tilted state due to a large rebound (restoration) of the coil spring SP, and help ensure the proper assembly state of the coil spring SP.

[0113] In addition, by reducing the rebound force (restoring force) of the coil spring SP when the coil spring SP is released from the clamp 7, it is possible to prevent the undesirable situation in which the seating surface of the coil spring SP (specifically, the spring abutment surface 451 of the arm portion 45 of the cam ring 4 and the other end wall 119b of the spring housing portion 119) is damaged when the coil spring SP is assembled.

[0114] The present invention is not limited to the configuration disclosed in the above-described embodiment, and can be freely changed according to, for example, the engine of a vehicle equipped with a variable displacement oil pump, the specifications of a valve timing control device, and the like.

[0115] In particular, in the above embodiment, the present invention is applied to a vane-type variable capacity oil pump, but the variable capacity oil pump to which the present invention can be applied is not limited to the vane-type variable capacity oil pump, and can also be applied to other types of variable capacity oil pumps, such as a trochoid pump. It should be noted that when the present invention is applied to a trochoid pump, the outer rotor constituting the external gear corresponds to the cam ring.

Claims

1. A variable capacity oil pump, characterized in that: have: a housing having a pump receiving portion; a cam ring movably received in the pump receiving portion; a pump assembly rotatably received on the inner circumference of the cam ring and forming a plurality of pump chambers together with the cam ring; a coil spring disposed in the pump housing portion and biasing the cam ring in a direction in which the eccentricity of the cam ring relative to the rotation axis of the pump assembly increases; The protrusion is provided on the cam ring and is partially formed so as to extend from a spring contact surface with which the coil spring contacts in the longitudinal direction of the coil spring and overlap a part of the outer circumference of the coil spring.

2. The variable displacement oil pump according to claim 1, characterized in that: The housing includes a first restriction wall that restricts the coil spring from moving outward in a radial direction orthogonal to a rotation axis of the pump assembly.

3. The variable displacement oil pump according to claim 1, characterized in that: The cam ring has a second restriction wall that restricts the coil spring from moving inward in a radial direction orthogonal to a rotation axis of the pump assembly.

4. The variable displacement oil pump according to claim 1, characterized in that: The protrusion is provided in a single piece.

5. The variable displacement oil pump according to claim 1, characterized in that: The protrusion is provided at a position overlapping with the center of the outer diameter of the coil spring.

6. The variable displacement oil pump according to claim 1, characterized in that: The housing has a third restriction wall that restricts movement of the coil spring to a side opposite to the protrusion in a radial direction of the coil spring.

7. The variable displacement oil pump according to claim 1, characterized in that: The coil spring is arranged in an oil passage extending from an oil suction port provided in the housing to the pump chamber. The protrusion is arranged on the downstream side of the coil spring in the oil passage.

8. A method for manufacturing a variable displacement pump, the method for manufacturing a variable displacement oil pump according to claim 1, characterized in that: have: a cam ring disposing step of disposing the cam ring in the pump housing portion; A coil spring configuration process, configuring the coil spring in the pump housing portion after the cam ring configuration process, wherein the coil spring is held in a compressed state by a clamp, the clamp having a two-pronged first retaining portion with a cutout in the middle portion and capable of retaining one end of the coil spring, and a second retaining portion capable of retaining the other end of the coil spring, the clamp being inserted between the cam ring and the pump housing portion in a manner that avoids the protrusion by utilizing the cutout of the first retaining portion, thereby configuring the coil spring in the pump housing portion.

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