Variable Displacement Oil Pump

Abstract

This variable capacity-type oil pump comprises: a connection path (31) linearly formed at a position adjacent to a first chamber (26) and a second chamber (27) when viewed in a direction along the rotation axis (O1) of a pump structure; a first chamber oil path (32) which branches from the connection path (31) and is connected to the first chamber (26); and a second chamber oil path (34) which branches from the connection path (31) and is connected to the second chamber (27). In addition, a valve section (28) of a solenoid valve (13) is inserted into a control valve accommodation section (30) provided in a block section (1k), the valve section including a part of the connection path (31).

Description

[Technical field]

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

[0002] 2. Description of the Related Art As a variable displacement oil pump, for example, the variable displacement oil pump described in Patent Document 1 below is known.

[0003] The variable displacement oil pump described in Patent Document 1 comprises a discharge portion which discharges oil to a main gallery, a first chamber into which oil from the main gallery is introduced and whose volume increases when the adjustment member moves in a direction in which the oil from the discharge portion decreases, and a second chamber into which oil from the main gallery is introduced via a control valve and whose volume increases when the adjustment member moves in a direction in which the pressure of the oil discharged from the discharge portion increases. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 071061 Summary of the Invention [Problem to be solved by the invention]

[0005] In the variable displacement oil pump described in Patent Document 1, oil passages for guiding oil from the main gallery to the first chamber and the second chamber are formed in a complex manner inside the housing.

[0006] The present invention was devised in consideration of the conventional situation, and aims to provide a variable displacement oil pump in which an oil passage for directing oil from the main gallery to the first chamber and the second chamber can be easily formed. [Means for solving the problem]

[0007] In the present invention, the variable displacement oil pump has a connecting passage formed in a straight line at a position adjacent to the first chamber and the second chamber when viewed from a direction along the rotational axis of the pump component, a first chamber oil passage branching off in a direction intersecting the longitudinal direction of the connecting passage and connected to the first chamber, and a second chamber oil passage branching off from the control valve accommodating portion in a direction intersecting the longitudinal direction of the connecting passage and connected to the second chamber, and a control valve is inserted into the control valve accommodating portion. Effect of the Invention

[0008] According to the present invention, an oil passage for guiding oil from the main gallery to the first chamber and the second chamber can be easily formed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an exploded perspective view of a variable displacement oil pump according to a first embodiment. [Diagram 2] 1 is a front view of a variable displacement oil pump according to a first embodiment. FIG. [Diagram 3] FIG. 2 is a perspective view of a housing body accommodating a cam ring, an electromagnetic valve, and the like. [Figure 4] FIG. 2A is a cross-sectional view of a solenoid valve accommodated in a control valve accommodating portion, and FIG. 2B is a cross-sectional view of a valve body taken along line AA in FIG. [Diagram 5] 1 is a cross-sectional view of a variable displacement oil pump showing a first state of a solenoid valve. [Figure 6] FIG. 4 is a cross-sectional view of the variable displacement oil pump showing a second state of the solenoid valve. [Figure 7] 3 is a characteristic diagram showing the correlation between the engine speed and the main gallery pressure of the variable displacement oil pump of the first embodiment. FIG. [Figure 8] FIG. 4 is a cross-sectional view of a solenoid valve according to a second embodiment. [Figure 9] FIG. 11 is a front view of a variable displacement oil pump according to a third embodiment, showing a state in which a solenoid valve is not in operation. [Figure 10] FIG. 11 is a front view of a variable displacement oil pump according to a third embodiment, showing an operating state of a solenoid valve. [Figure 11] FIG. 11 is a front view of a variable displacement oil pump according to a fourth embodiment, showing a state in which a solenoid valve is not in operation. [Figure 12] FIG. 11 is a front view of a variable displacement oil pump according to a fourth embodiment, showing an operating state of a solenoid valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a variable displacement oil pump according to the present invention will be described with reference to the drawings.

[0011] [First embodiment] (Configuration of variable displacement oil pump) Fig. 1 is an exploded perspective view of a variable displacement oil pump of a first embodiment provided in a cylinder block of an internal combustion engine (not shown), etc. Fig. 2 is a front view of the variable displacement oil pump of the first embodiment with the front cover removed. Fig. 3 is a perspective view of a housing body 1 accommodating a cam ring 6, a solenoid valve 13, etc. In Fig. 3, components within the cam ring 6 are omitted to clarify flow paths such as a connection path 31, and the housing body 1 is shown by a schematic imaginary line.

[0012] The variable displacement oil pump comprises a housing consisting of a housing body 1 and a cover member 2, a drive shaft 3, a rotor 4, a plurality of vanes 5 (seven in this embodiment), a cam ring 6 as an adjustment member, a first coil spring 7, a pair of ring members 8, first to third sealing means 9 to 11, five fixing means, such as a screw member 12, a solenoid valve 13, and a relief valve 14.

[0013] The housing body 1 is integrally formed from a metal material, for example, an aluminum alloy material, and is formed in a bottomed tubular shape with one end open and a pump accommodation chamber 1a recessed in a generally cylindrical shape inside. As shown in Fig. 1, the housing body 1 has a first bearing hole 1c for rotatably supporting one end of the drive shaft 3 at the center of the bottom surface 1b of the pump accommodation chamber 1a. The housing body 1 is formed with a flat mounting surface 1d that is continuous in an annular shape on the outer periphery side of the opening of the pump accommodation chamber 1a. The mounting surface 1d of the housing body 1 is formed with five screw holes 1e into which the screw members 12 are screwed.

[0014] The cover member 2 is formed of a metal material, such as an aluminum alloy material, like the housing body 1, and is used to close the opening of the housing body 1. The cover member 2 is flat and has an outer shape corresponding to the outer shape of the housing body 1. The cover member 2 is formed with a second bearing hole 2a that rotatably supports the other end of the drive shaft 3 at a position corresponding to the first bearing hole 1c of the housing body 1. Furthermore, the cover member 2 is formed on its outer periphery with five fixing means through holes 2b (four fixing means through holes 2b are shown in FIG. 1) into which the respective screw members 12 are inserted at positions corresponding to the five screw holes 1e of the housing body 1.

[0015] The housing body 1 and the cover member 2 form a housing that separates the pump accommodating chamber 1a.

[0016] The drive shaft 3 passes through the center of the pump housing chamber 1a and is rotatably supported by the housing, and is rotationally driven by a crankshaft (not shown). The drive shaft 3 rotates the rotor 4 in the counterclockwise direction in FIG. 2 by the torque transmitted from the crankshaft.

[0017] The rotor 4 is cylindrical and rotatably accommodated in the pump accommodation chamber 1a. The center of the rotor 4 is coupled to the drive shaft 3. As shown in FIG. 1 and FIG. 2, the rotor 4 has seven slits 4a that extend radially from the inner center side of the rotor 4 to the outside in the radial direction. Also, as shown in FIG. 1 and FIG. 2, the inner base end of each slit 4a has a back pressure chamber 4b with a circular cross section that introduces the discharged oil discharged to the discharge port 24 described later. As shown in FIG. 2, the back pressure chamber 4b opens to a circular recess 4c formed on both side surfaces of the rotor 4. Oil from a second chamber 27 described later flows into the back pressure chamber 4b through the discharge port 24, an oil introduction groove (not shown) formed on the bottom surface 1b of the pump accommodation chamber 1a, and the circular recess 4c. As a result, each vane 5 accommodated in the slit 4a of the rotor 4 so as to be able to protrude and retract is pushed outward by the centrifugal force accompanying the rotation of the rotor 4 and the hydraulic pressure of the back pressure chamber 4b.

[0018] The vane 5 is made of metal and formed into a thin plate shape, and is housed in the slit 4a of the rotor 4 so as to be able to appear and disappear. When the vane 5 is housed in the slit 4a, a small gap is formed between the vane 5 and the slit 4a. When the rotor 4 rotates, the tip surface of the vane 5 slidably contacts the inner peripheral surface of the cam ring 6, and the inner end surface of the base end slidably contacts the outer peripheral surface of the ring member 8. As a result, even when the engine speed is low and the centrifugal force and the hydraulic pressure in the back pressure chamber 4b are small, the vane 5 slidably contacts the inner peripheral surface of the cam ring 6, and each pump chamber 15 is liquid-tightly defined.

[0019] The drive shaft 3, rotor 4 and vanes 5 constitute a pump component. The cam ring 6 surrounding this pump component is integrally formed into a cylindrical shape from sintered metal. A first coil spring 7 located on the outer periphery of the cam ring 6 is contained within the housing body 1 and constantly biases the cam ring 6 in a direction that increases the eccentricity of the cam ring 6 with respect to the center of rotation of the rotor 4. A ring member 8 is slidably disposed within a circular recess 4c provided in the rotor 4.

[0020] The first to third seal means 9 to 11 are attached to the cam ring 6 so as to be slidable on the first to third seal contact surfaces 1g, 1h, and 1i, and partition the cam ring 6 and the housing body 1. As a result, first and second chambers 26 and 27, which are control hydraulic chambers, are liquid-tightly defined between the outer peripheral surface of the cam ring 6 and the inner peripheral surface of the housing body 1. The first seal means 9 includes a first seal member 16 and a first elastic member 17 that biases the first seal member 16 toward the inner peripheral surface of the housing body 1. The second seal means 10 includes a second seal member 18 and a second elastic member 19 that biases the second seal member 18 toward the inner peripheral surface of the housing body 1. The third seal means 11 includes a third seal member 20 and a third elastic member 21 that biases the third seal member 20 toward the inner peripheral surface of the housing body 1.

[0021] As shown in Fig. 1, a circular support hole 1f is formed at a predetermined position on the inner peripheral wall of the pump accommodation chamber 1a, which supports the cam ring 6 so that it can swing via a cylindrical pivot pin 22. For convenience of the following explanation, in Fig. 2, a straight line passing through the center of the first bearing hole 1c (the rotation axis O1 of the pump constituent body) and the center of the support hole 1f (the center O2 of the pivot pin 22) is defined as a "cam ring reference line M."

[0022] As shown in Fig. 2, a first seal contact surface 1g is formed on the inner peripheral wall of the pump accommodation chamber 1a in an area on one side (the right side in Fig. 2) of the cam ring reference line M. A first seal member 16 provided on the outer peripheral portion of the cam ring 6 comes into slidable contact with this first seal contact surface 1g. As shown in Fig. 2, the first seal contact surface 1g is an arc surface defined by a predetermined radius R1 from the center O2 of the pivot pin 22. The radius R1 is set to a circumferential length that allows the first seal member 16 to constantly slidably contact the first seal member 16 within the eccentric swing range of the cam ring 6.

[0023] Similarly, as shown in Fig. 2, a second seal contact surface 1h is formed on the inner peripheral wall of the pump accommodation chamber 1a in an area on the other side (left side in Fig. 2) of the cam ring reference line M. A second seal member 18 provided on the outer peripheral portion of the cam ring 6 comes into slidable contact with this second seal contact surface 1h. As shown in Fig. 2, the second seal contact surface 1h is an arc surface defined by a predetermined radius R2 smaller than the radius R1 from the center O2 of the pivot pin 22. The radius R2 is set to a circumferential length with which the second seal member 18 can always come into slidable contact within the eccentric swing range of the cam ring 6.

[0024] Furthermore, as shown in Fig. 2, a third seal contact surface 1i is formed on the inner peripheral wall of the pump accommodation chamber 1a in a region to the left of the cam ring reference line M and at a position farther from the pivot pin 22 than the second seal contact surface 1h. A third seal member 20 provided on the outer periphery of the cam ring 6 slidably contacts this third seal contact surface 1i. As shown in Fig. 2, the third seal contact surface 1i is an arc surface defined by a predetermined radius R3 larger than the radius R1 from the center O2 of the pivot pin 22. The radius R3 is set to a circumferential length with which the third seal member 20 can always slidably contact within the eccentric swing range of the cam ring 6.

[0025] 2, a suction port 23, which is an arc-shaped suction portion, and a discharge port 24, which is an arc-shaped discharge portion, are cut out in the bottom surface 1b of the pump accommodation chamber 1a in the outer circumferential region of the drive shaft 3 so as to face each other across the drive shaft 3. The suction port 23 is located on the opposite side of the bottom surface 1b to the pivot pin 22, and opens into a region (suction region) where the internal volume of a pump chamber 15, which will be described later, increases with the pumping action of the pump constituent body.

[0026] Furthermore, an inlet groove (not shown) having the same shape as the inlet port 23 is formed on the inner surface of the cover member 2 at a position corresponding to the inlet port 23, and this inlet groove communicates with an inlet hole 2c (see FIG. 1) provided in the cover member 2. As a result, oil stored in an oil pan of the internal combustion engine (not shown) is sucked into each pump chamber 15 (described later) in the inlet region through the inlet hole 2c and the inlet groove of the cover member 2 based on negative pressure generated by the pumping action of the pump constituent body.

[0027] On the other hand, the discharge port 24 is located on the pivot pin 22 side and opens into a region (discharge region) where the internal volume of the pump chamber 15 decreases with the pumping action of the pump component. A discharge hole 1j having a circular cross section is provided near the start end of the discharge port 24, penetrating the side wall of the housing body 1 and opening to the outside, as shown in FIG. 1. As a result, the oil pressurized based on the pumping action and discharged to the discharge port 24 is supplied from the discharge hole 1j through a discharge passage (not shown) and a main gallery (not shown) to each sliding part of the internal combustion engine, a valve timing device, etc. (not shown). Note that a discharge groove (not shown) having the same shape as the discharge port 24 is formed at a position corresponding to the discharge port 24 on the inner side surface of the cover member 2.

[0028] Furthermore, within housing body 1, a spring accommodating chamber 25 for accommodating first coil spring 7 is provided at a position facing flat portion 6a provided on the outer periphery of cam ring 6 between second seal member 18 and third seal member 20. Within this spring accommodating chamber 25, first coil spring 7 compressed by a predetermined set load W1 elastically abuts against one end wall of spring accommodating chamber 25 and flat portion 6a. In this manner, first coil spring 7, with an elastic force based on set load W1, constantly biases cam ring 6 in a direction that increases its eccentricity (counterclockwise direction in FIG. 2) via flat portion 6a.

[0029] Furthermore, as shown in FIG. 2, the first to third seal retaining portions 6b to 6d having the first to third seal surfaces protrude from the outer periphery of the cam ring 6 at positions facing the first to third seal contact surfaces 1g to 1i. Here, the first to third seal surfaces are formed with a predetermined radius slightly smaller than the radius R1, R2, and R3 constituting the corresponding seal contact surfaces 1g, 1h, and 1i from the center O2 of the pivot pin 22. A minute clearance is formed between each seal surface and each seal contact surface 1g, 1h, and 1i. In addition, the first and second seal retaining grooves 6e, 6f, and 6g having a U-shaped cross section are formed along the axial direction of the cam ring 6 on the seal surfaces of the seal retaining portions 6b, 6c, and 6d. First to third seal members 16, 18, 20 that come into contact with first to third seal contact surfaces 1g, 1h, 1i when cam ring 6 eccentrically swings are held in first to third seal retaining grooves 6e to 6g, respectively.

[0030] In addition, in the outer peripheral region of the cam ring 6, a first chamber 26 is defined by the outer peripheral portion of the approximately circular support wall portion 6j of the cam ring 6 surrounding the pivot pin 22 and the first seal member 16, while a second chamber 27 is defined by the second seal member 18 and the third seal member 20. The pump discharge pressure is introduced to the first chamber 26 via a first chamber oil passage 32 described later, while the pump discharge pressure is supplied to the second chamber 27 via the first chamber oil passage 32, a connection passage 31 described later, and a second chamber oil passage 34. The first chamber 26 is configured so that the volume increases when the cam ring 6 moves in a direction in which the flow rate of the oil discharged from the discharge port 24 decreases, by guiding the oil discharged from the discharge port 24. The second chamber 27 is a space including the spring accommodating chamber 25, and is configured so that the volume increases when the cam ring 6 moves in a direction in which the flow rate of the oil discharged from the discharge port 24 increases.

[0031] The surface of the outer circumferential surface of the cam ring 6 that is adjacent to the first chamber 26 serves as a first pressure-receiving surface 6h that receives the pump discharge pressure introduced into the first chamber 26. Moreover, the surface of the outer circumferential surface of the cam ring 6 that is adjacent to the second chamber 27 serves as a second pressure-receiving surface 6i (including a flat portion 6a) that receives the pump discharge pressure introduced into the second chamber 27.

[0032] Then, the pump discharge pressures act on the corresponding first and second pressure-receiving surfaces 6h, 6i of the cam ring 6, and the amount of eccentricity of the cam ring 6 is controlled by the balance between the biasing force based on the hydraulic pressure acting on the first and second pressure-receiving surfaces 6h, 6i and the biasing force of the first coil spring 7. Here, the pressure-receiving area of ​​the first pressure-receiving surface 6h is set larger than the pressure-receiving area of ​​the second pressure-receiving surface 6i, and when hydraulic pressure acts on both pressure-receiving surfaces 6h, 6i, the cam ring 6 is biased in a direction that reduces the amount of eccentricity as a whole.

[0033] The solenoid valve 13 corresponds to the control valve of the present invention and includes a valve portion 28 that supplies and discharges oil depending on the axial position in the moving direction of a spool 40 described later, and a solenoid portion 29 that controls the axial position of the spool 40 by energizing it. The solenoid valve 13 is provided in a regular hexahedral block portion 1k that is integrally formed on the back surface of the housing main body 1 as shown in Fig. 1. More specifically, the valve portion 28 located on the tip side of the solenoid valve 13 is accommodated in a control valve accommodating portion 30 that is recessed into one surface 1m of the block portion 1k as shown in Fig. 1, and the solenoid portion 29 located on the rear end side of the solenoid valve 13 protrudes outward from the surface 1m of the block portion 1k. In a state where the valve portion 28 is accommodated in the control valve accommodating portion 30, when viewed in a direction along the rotation axis O1 of the pump constituent body as shown in Fig. 2, the tip of the valve portion 28 overlaps with the region of the cam ring 6 between the first chamber 26 and the second chamber 27, and the solenoid portion 29 is located outside the second chamber 27. In other words, when viewed in a direction along the rotation axis O1 of the pump constituent body as shown in Fig. 2, the tip of the valve portion 28 is provided so as to face the region of the cam ring 6 between the first chamber 26 and the second chamber 27, and the solenoid portion 29 is provided so as not to face the second chamber 27. Various components and functions of the solenoid valve 13 will be described in detail later.

[0034] In addition, the housing body 1 is formed with a linear connection passage (linear oil passage portion) 31 (shown by a virtual line) that is located on the central axis Z of the solenoid valve 13 when viewed from the direction along the rotation axis O1 of the pump constituent body as shown in FIG. 2, and through which oil from the main gallery is guided via an inlet 33 and a first chamber oil passage 32 described later. As shown in FIG. 2, the connection passage 31 is provided at a position adjacent to the pivot pin 22 in the region between the pivot pin 22, which is the swing fulcrum of the cam ring 6, and the drive shaft 3 of the pump constituent body. That is, the connection passage 31 is provided so as to connect a portion P1 located on the pivot pin 22 side of the first chamber 26 and a portion P2 located on the pivot pin 22 side of the second chamber 27 along the central axis Z in the radial direction relative to the rotation axis O1, by the shortest distance. The outer diameter of the connection passage 31 is set to be smaller than the inner diameter of the control valve accommodating portion 30.

[0035] As shown in FIG. 3, one end of the connection passage 31 is connected to the first chamber 26 via the first chamber oil passage 32 that branches in a direction intersecting the longitudinal direction of the connection passage 31. More specifically, one end of the connection passage 31 is connected to the first chamber 26 via the first chamber oil passage 32 that branches perpendicular to the longitudinal direction of the connection passage 31. The first chamber oil passage 32 opens toward the first chamber 26 at a point P1 on the first chamber 26 when viewed from a direction along the rotation axis O1 as shown in FIG. 2. As shown in FIG. 3, the outer periphery of the first chamber oil passage 32 is connected to an inlet 33 through which oil from the main gallery is introduced, at a position between the first chamber 26 and the connection passage 31 and closer to the connection passage 31. As shown in FIG. 3, the inlet 33 extends to the outer periphery of the first chamber oil passage 32 so as to be perpendicular to the surface 1n on which the discharge hole 1j is provided in the housing main body 1. Oil from the main gallery is introduced into the first chamber 26 via an inlet 33 and a first chamber oil passage 32.

[0036] As shown in FIG. 3, the other end of the connection passage 31 passing through the solenoid valve 13 is connected to the second chamber 27 via the second chamber oil passage 34 that branches in a direction intersecting the longitudinal direction of the connection passage 31. More specifically, the other end of the connection passage 31 is connected to the second chamber 27 via the second chamber oil passage 34 that branches in a direction perpendicular to the longitudinal direction of the connection passage 31. As shown in FIG. 3, the second chamber oil passage 34 extends parallel to the first chamber oil passage 32. When viewed from the direction along the rotation axis O1 as shown in FIG. 2, the second chamber oil passage 34 opens toward the second chamber 27 at a position P2 on the second chamber 27. Oil from the main gallery is introduced into the second chamber 27 via the inlet 33, the first chamber oil passage 32, the connection passage 31, and the second chamber oil passage 34.

[0037] The relief valve 14 is accommodated in a valve accommodation hole 35 (shown by an imaginary line in FIG. 2) formed near the discharge port 24 as shown in FIG. 2, and functions to open and release the discharge pressure to the outside when the discharge pressure of the variable displacement oil pump is higher than a predetermined discharge pressure. The relief valve 14 includes a lid 36 that closes the valve accommodation hole 35, a spring 37 having one end abutting against the lid 36, and a ball 38 with which the other end of the spring 37 abuts. When the discharge pressure of the variable displacement oil pump is higher than a predetermined discharge pressure, the discharge pressure acts on the ball 38, and when the ball 38 contracts the spring 37 against the lid 36, the discharge pressure is released to the outside via a relief hole (not shown) provided on the back side of the ball 38. (Solenoid valve configuration) FIG. 4(a) is a cross-sectional view of the solenoid valve 13 accommodated in the control valve accommodating portion 30, and FIG. 4(b) is a cross-sectional view of the valve body 39 taken along the line AA in FIG. 4(a).

[0038] 4(a), the control valve accommodating portion 30 has a bottom portion 30a where the connection passage 31 opens and which expands in diameter in a conical shape toward the solenoid portion 29, and a control valve accommodating port 30b formed at a position axially opposite to the bottom portion 30a. The valve portion 28 of the solenoid valve 13 is inserted into the control valve accommodating portion 30 from the control valve accommodating port 30b toward the bottom portion 30a.

[0039] Here, the connecting passage 31 actually includes a tip side passage 31b, an axial passage 31c, a first valve opening 31d, an introduction passage 31e, and a second valve opening 31f, which will be described later. However, in order to clarify the flow path, the connecting passage 31 between the first chamber oil passage 32 and the bottom 30a will be described below as the "connecting passage inlet portion 31a."

[0040] The valve portion 28 of the solenoid valve 13 includes a generally cylindrical valve body 39, a spool 40 slidably disposed within the valve body 39, a retainer 41 fixed to the inner periphery of the valve body 39, and a second coil spring 64 serving as a biasing member disposed between the retainer 41 and the spool 40 with a predetermined set load W2 applied thereto.

[0041] The valve body 39 has a spool accommodating portion 39a that slidably accommodates the spool 40. The spool accommodating portion 39a is equipped with a large diameter cylindrical portion 39b located on the connection passage inlet portion 31a side, and a small diameter cylindrical portion 39c that is formed integrally with the large diameter cylindrical portion 39b and has an inner diameter smaller than that of the large diameter cylindrical portion 39b.

[0042] A disk-shaped metallic retainer 41 constituting a fixed portion is press-fitted and fixed to the inner peripheral surface near one end of the large diameter cylindrical portion 39b so as to axially face the bottom 30a of the control valve accommodating portion 30 where the connection passage inlet 31a opens. The retainer 41 forms a tip-side passage 31b between the bottom 30a of the control valve accommodating portion 30 and the retainer 41, into which oil is introduced via the connection passage inlet 31a. The surface 41a of the retainer 41 facing the second coil spring 64 is the surface against which one axial end of the second coil spring 64 elastically abuts.

[0043] As shown in Fig. 4(a) and Fig. 4(b), two flat parts 39d formed in a two-face width shape are formed at positions facing each other in the radial direction on the outer periphery of the large diameter cylindrical part 39b. A recess 39f is formed between the flat part 39d and a step part 39e provided on one axial end side of the outer periphery of the small diameter cylindrical part 39c, and the recess 39f is connected to the tip side passage 31b to form an axial passage 31c through which oil from the tip side passage 31b flows in the axial direction of the valve body 39. A first valve opening 31d is formed at a position near the step part 39e among the flat parts 39d, which penetrates the flat part 39d and the inner periphery of the large diameter cylindrical part 39b and communicates with the axial passage 31c. The first valve opening 31d is always in communication with an introduction passage 31e provided around a middle shaft part 40b (described later) of the spool 40.

[0044] Four second valve openings 31f are formed at positions of the small diameter cylindrical portion 39c near the step portion 39e, penetrating the inner peripheral surface and the outer peripheral surface of the small diameter cylindrical portion 39c. The second valve openings 31f are provided at positions equally spaced apart in the circumferential direction of the valve body 39. One of the four second valve openings 31f faces the second chamber oil passage 34 formed in the block portion 1k. Four third valve openings 62 are formed at positions of the small diameter cylindrical portion 39c near the solenoid portion 29, penetrating the inner peripheral surface and the outer peripheral surface of the small diameter cylindrical portion 39c. The third valve openings 62 are provided at positions equally spaced apart in the circumferential direction of the valve body 39, and face an external connection passage 63 provided near the control valve accommodation port 30b of the control valve accommodation portion 30. The external connection passage 63 communicates with the outside, for example, an oil pan (not shown), which has a lower pressure than the pressure of the oil discharged from the discharge port 24.

[0045] Furthermore, an annular groove 39g into which a first seal ring 42, which is an O-ring, is fitted is formed on the outer circumferential surface of the small diameter cylindrical portion 39c, at a position between the second valve opening 31f and the third valve opening 62. The first seal ring 42 provides a liquid-tight seal between the inner circumferential surface of the control valve accommodating portion 30 and the outer circumferential surface of the small diameter cylindrical portion 39c.

[0046] The spool 40 has a large diameter portion 40a, an intermediate shaft portion 40b formed integrally with the large diameter portion 40a, a medium diameter portion 40c formed integrally with the intermediate shaft portion 40b and having a smaller diameter than the large diameter portion 40a and a larger diameter than the intermediate shaft portion 40b, and a rear end shaft portion 40d formed integrally with the medium diameter portion 40c. The spool 40 is disposed so that the large diameter portion 40a is located on the connection passage inlet portion 31a side as shown in FIG. 4(a).

[0047] The large diameter portion 40a slides on the inner peripheral surface of the valve body 39 between the first valve opening 31d and the retainer 41. A circular groove portion 40e that accommodates the other axial end portion of the second coil spring 64 is formed in one axial end surface 40n of the large diameter portion 40a. A spring accommodating portion 65 that accommodates the second coil spring 64 is provided between a bottom surface 40f of the circular groove portion 40e and the retainer 41. The bottom surface 40f of the circular groove portion 40e is a surface against which the other axial end portion of the second coil spring 64 elastically abuts. A drain connection passage 40g is formed in the center of the bottom surface 40f of the circular groove portion 40e, extending axially from the bottom surface 40f across the medium diameter portion 40c to a position just before the center of the rear end shaft portion 40d. A rectangular spool drain hole 40h is formed radially through the end of the drain connection passage 40g, that is, the end located on the rear end shaft portion 40d side. The spool drain holes 40h are provided at two positions facing each other in the radial direction and communicate with the outside through a hole (not shown) provided in the block portion 1k. When the temperature of the air in the spring accommodating portion 65 rises during operation of the internal combustion engine and the air expands, the expanded air is discharged to the outside through the drain connection passage 40g, the spool drain hole 40h, and the hole.

[0048] In addition, the other axial end face of the large diameter portion 40a is an annular first pressure-receiving surface portion 40i upon which the main gallery pressure P introduced via the connection passage inlet portion 31a, the tip side passage 31b, the axial passage 31c and the first valve opening 31d acts.

[0049] The intermediate shaft portion 40b is integrally formed at the other axial end of the large diameter portion 40a, and forms an introduction passage 31e between itself and the inner surface of the large diameter cylindrical portion 39b of the valve body 39, which is connected to the axial passage 31c via the first valve opening 31d.

[0050] The medium diameter portion 40c is integral with the other axial end of the intermediate shaft portion 40b so as to face the large diameter portion 40a in the axial direction with the intermediate shaft portion 40b in between, and slides against the inner peripheral surface of the small diameter cylindrical portion 39c on the solenoid portion 29 side from the second valve opening 31f. One axial end surface of the medium diameter portion 40c is an annular second pressure receiving surface portion 40j on which the main gallery pressure P introduced through the connection passage inlet portion 31a, the tip side passage 31b, the axial passage 31c, and the first valve opening 31d acts. The second pressure receiving surface portion 40j is set smaller than the first pressure receiving surface portion 40i. The hydraulic pressure Fp for urging the spool 40 toward the tip portion of the valve body 39 is calculated by multiplying the main gallery pressure P by the difference in pressure receiving area between the first pressure receiving surface portion 40i of the large diameter portion 40a and the second pressure receiving surface portion 40j of the medium diameter portion 40c.

[0051] The rear end shaft portion 40d is integrally provided on the other axial end of the medium diameter portion 40c, and an axial end face 40k is capable of abutting against a rod 50 of the solenoid portion 29, which will be described later.

[0052] The solenoid portion 29 is provided at the rear end of the valve body 39, and includes a case 43, a blocking member 44, a coil 45, a bobbin 46, a fixed core 47, a solenoid portion sleeve 48, a movable core 49, and a rod 50.

[0053] The case 43 is formed in a cylindrical shape and accommodates therein the coil 45, the bobbin 46, the fixed core 47, the solenoid sleeve 48, the movable core 49, and the rod 50. The case 43 is closed by a cylindrical closing member 44 with a bottom.

[0054] The coil 45 is wound around a bobbin 46 formed in a generally cylindrical shape. A generally cylindrical solenoid sleeve 48 is press-fitted and fixed to the inner peripheral surface of the bobbin 46 at one axial end 46a. A movable core 49 is provided on the inner peripheral side of the solenoid sleeve 48 so as to be movable along the axial direction. A generally cylindrical fixed core 47 is press-fitted and fixed to the inner peripheral surface of the bobbin 46 at the other axial end 46b. A rod 50 is provided on the inner peripheral side of the fixed core 47, which is movable in the axial direction by moving integrally with the movable core 49 as the movable core 49 moves. A tip portion 50a of the rod 50 is capable of biasing an axial end surface 40k of a rear end shaft portion 40d of a spool 40 housed in a valve body 39 as the rod 50 moves toward the one axial end side. Furthermore, the space between the fixed core 47 and the valve body 39 is liquid-tightly sealed by an annular seal member, for example, a second seal ring 51, which is an O-ring. Similarly, the space between the fixed core 47 and the bobbin 46 is liquid-tightly sealed by an annular seal member, for example, a third seal ring 52, which is an O-ring.

[0055] In the solenoid valve 13, the solenoid unit 29 biases the rear end shaft portion 40d of the spool 40 from the rear end portion toward the front end portion of the valve body 39 in response to an electric signal applied from the outside. More specifically, when a pulse voltage is applied to the coil 45 of the solenoid unit 29 from an electronic controller (not shown), a thrust corresponding to the voltage value of the pulse voltage acts on the movable iron core 49. The spool 40 is then moved forward and backward based on the relative difference between the resultant force Fp+Fr of the hydraulic pressure Fp applied to the spool 40 and the thrust of the movable iron core 49 (the pressing force Fr of the rod 50) transmitted via the rod 50, and the spring force Fs2 of the second coil spring 64.

[0056] The electronic controller uses a so-called PWM (pulse width modulation) method, and modulates the pulse width of the pulse voltage applied to the coil 45, i.e., changes the duty ratio D to continuously control the voltage value of the pulse voltage applied to the coil 45. The electronic controller detects the engine operating state from the engine oil temperature, water temperature, engine speed, load, etc., and cuts off the power supply to the coil 45 when the engine is in a low speed state, particularly when the engine is started, but energizes the coil 45 to adjust the main gallery pressure P when the engine speed N reaches a predetermined value or more.

[0057] Fig. 5 is a cross-sectional view of the variable displacement oil pump showing the first state of solenoid valve 13, and Fig. 6 is a cross-sectional view of the variable displacement oil pump showing the second state of solenoid valve 13. Note that in Figs. 5 and 6, solenoid valve 13 is disposed to the side of cam ring 6 in order to show the axial position of the spool and the flow of oil through solenoid valve 13, but in reality, cam ring 6 and solenoid valve 13 have the positional relationship shown in Figs. 1 to 3 as described above. Fig. 7 is a characteristic diagram showing the correlation between engine speed N and main gallery pressure P of the variable displacement oil pump of the first embodiment.

[0058] The operation of the solenoid valve 13 and the associated operation of the cam ring 6 will be described below.

[0059] First, when the coil 45 of the solenoid valve 13 is not energized, that is, when the duty ratio D is 0%, the spool 40 moves in the axial direction within the valve body 39 based on the hydraulic pressure Fp applied to the spool 40 and the spring force Fs2 of the second coil spring 64. More specifically, when the hydraulic pressure Fp is greater than the spring force Fs, the spool 40 moves toward the tip end of the valve body 39, whereas when the spring force Fs2 is greater than the hydraulic pressure Fp, the spool 40 moves toward the rear end of the valve body 39.

[0060] As shown in FIG. 7, when the engine speed N is equal to or lower than a predetermined engine speed N2, the main gallery pressure P is equal to or lower than a predetermined value P2. Here, the predetermined value P2 indicates the engine required oil pressure required for lubricating the bearing of the crankshaft at high engine speed. In addition, the hydraulic pressure Fp, which is proportional to the main gallery pressure P, is equal to or lower than a predetermined value, and the hydraulic pressure Fp is equal to or lower than the spring force Fs2. Therefore, the spool 40 is in a position closer to the solenoid portion 29 (the position of the spool 40 shown in FIG. 5). At this time, the communication between the second valve opening 31f and the external connection passage 63 is blocked by the outer circumferential surface of the medium diameter portion 40c, and the first valve opening 31d and the second valve opening 31f are communicated via the introduction passage 31e. As a result, as shown in FIG. 5, the oil in the main gallery is guided to the second chamber 27 via the first chamber oil passage 32, the connection passage inlet 31a, the tip side passage 31b, the axial passage 31c, the first valve opening 31d, the introduction passage 31e, the second valve opening 31f, and the second chamber oil passage 34. Then, the resultant force PO2+Fs1 of the internal pressure PO2 of the second chamber 27 and the spring force Fs1 of the first coil spring exceeds the internal pressure PO1 of the first chamber 26. Therefore, the cam ring 6 is in the most eccentric position (the position of the cam ring 6 shown in FIG. 5), and the amount of eccentricity is maximum. At this time, the solenoid valve 13 is in the first state in which the tip side passage 31b and the second chamber 27 are connected via the axial passage 31c, the first valve opening 31d, the introduction passage 31e, the second valve opening 31f, and the second chamber oil passage 34. Therefore, as shown in FIG. 7, when the engine speed N is equal to or lower than a predetermined engine speed N2, the main gallery pressure P changes according to the engine speed N at the maximum displacement.

[0061] Also, when the engine speed N is greater than the predetermined engine speed N2, when the main gallery pressure P reaches the predetermined value P2, the hydraulic pressure Fp reaches the predetermined value and becomes greater than the spring force Fs2. Then, the spool 40 moves slightly toward the tip end of the valve body 39 by a predetermined distance (the position of the spool 40 shown in FIG. 6). During this movement, the duty ratio D is 0%, so the rod 50 is in the most retreated position and is separated from the other axial end of the spool 40. In addition, the second valve opening 31f communicates with the external connection passage 63, and the oil in the second chamber 27 is discharged to the outside via the second chamber oil passage 34, the second valve opening 31f, the discharge passage 60, the third valve opening 62, and the external connection passage 63. At this time, the solenoid valve 13 is in the second state in which the second chamber 27 is connected to the external connection passage 63 via the second chamber oil passage 34, the second valve opening 31f, the discharge passage 60, and the third valve opening 62. As a result, the internal pressure PO1 in the first chamber 26 becomes high, and this internal pressure PO1 urges the cam ring 6 toward the first coil spring 7 against the spring force Fs1 of the first coil spring 7. Then, the cam ring 6 moves toward the first coil spring 7, and the eccentricity becomes smaller. As a result, the discharge amount of the variable displacement pump decreases, and the main gallery pressure P decreases toward the predetermined value P2. Also, when the main gallery pressure P decreases to or below the predetermined value P2, the oil pressure in the first chamber 26 becomes low again, the cam ring 6 moves to a position on the first chamber 26 side, and the capacity increases.

[0062] In this way, when the main gallery pressure P is smaller than the predetermined value P2, the spool 40 is in a position closer to the solenoid portion 29, connecting the main gallery to the second chamber 27, whereas when the main gallery pressure P reaches the predetermined value P2, the spool 40 is in a position away from the solenoid portion 29, connecting the second chamber 27 to the outside. As a result, the main gallery pressure P is maintained at the predetermined value P2 or in a range near the predetermined value P2 (control oil pressure Pt2).

[0063] Also, when the coil 45 of the solenoid valve 13 is energized, that is, when the duty ratio D is X (0 < X < 100)%, the spool 40 moves axially within the valve body 39 based on the resultant force Fp + Fr of the hydraulic pressure Fp applied to the spool 40 and the pressing force Fr of the rod 50, and the spring force Fs2 of the second coil spring 64. More specifically, when the resultant force Fp + Fr is greater than the spring force Fs2, the spool 40 moves toward the tip end side of the valve body 39, while when the spring force Fs2 is greater than the resultant force Fp + Fr, the spool 40 moves toward the rear end side of the valve body 39. When moving toward one end side of the valve body 39, since the pressing force Fr assists the hydraulic pressure Fp, the main gallery pressure P moves the spool 40 with a predetermined pressure Px lower than the predetermined value P2. Accordingly, the control hydraulic pressure controlled by the spool 40 also becomes a predetermined control hydraulic pressure Ptx lower than the control hydraulic pressure Pt2. Also, when the duty ratio D is at the maximum value, that is, 100%, the control hydraulic pressure Pt1 controlled by the spool 40 is maintained within the range of P1 which is the lowest hydraulic pressure or near P1.

[0064] Note that when the engine is in a low rotation state such as at engine start, that is, when the engine rotation speed N is lower than N1, the energization to the coil 45 is cut off and the duty ratio D is 0%.

[0065] [Effects of the First Embodiment] In a variable displacement oil pump of the prior art, in order to form an oil passage that guides oil from the main gallery to the first chamber and also to the second chamber via a solenoid valve, the mating surface between the housing body and the cover member is utilized, and in some cases, a lateral hole is formed to bypass the discharge port. For this reason, there has been a problem that the oil passage becomes relatively long and complex, making it difficult to form the oil passage. Also, there have been problems such as the variable displacement oil pump becoming larger in size, the sealing performance of the mating surface between the housing body and the cover member deteriorating, and the responsiveness of the hydraulic pressure between the second chamber and the solenoid valve deteriorating.

[0066] In the first embodiment, the variable displacement oil pump has a connecting passage 31 formed in a straight line at a position adjacent to the first chamber 26 and the second chamber 27 when viewed from a direction along the rotational axis O1 of the pump structure, a first chamber oil passage 32 branching off in a direction intersecting the longitudinal direction of the connecting passage 31 and connected to the first chamber 26, and a second chamber oil passage 34 branching off from the control valve accommodating portion 30 in a direction intersecting the longitudinal direction of the connecting passage 31 and connected to the second chamber 27, and an electromagnetic valve 13 constituting a part of the connecting passage 31 is inserted into the control valve accommodating portion 30.

[0067] Therefore, the oil passages are sealed by the valve portion 28 of the solenoid valve 13 and the seal ring 42 provided on its outer periphery, with the solenoid valve 13 itself directly connected to the first chamber oil passage 32 and the second chamber oil passage 34, which are the only horizontal holes. Therefore, a relatively long seal by the mating surface between the housing body 1 and the cover member 2 is not required, so that an oil passage for guiding oil from the main gallery to the first chamber 26 and the second chamber 27 can be easily formed. In addition, it is also possible to suppress a decrease in the sealing performance between the solenoid valve 13 and the first and second chambers 26, 27. In addition, because the oil passages are short, the variable displacement oil pump can be made smaller, and the manufacturing costs related to the pump can be reduced.

[0068] Furthermore, in the configuration of the variable displacement oil pump of the first embodiment, the solenoid valve 13 is disposed in a position close to the second chamber 27, and the oil from the main gallery is guided to the second chamber 27 via a relatively short oil passage including the linear connecting passage 31 and the second chamber oil passage 34, so that it is possible to improve the hydraulic response to the second chamber 27. Furthermore, when discharging oil from the second chamber 27 to the outside, it is sufficient to discharge the oil via the second chamber oil passage 34 and the solenoid valve 13, so that even in such a case, the hydraulic response can be improved.

[0069] Furthermore, in the first embodiment, the solenoid valve 13 is configured to be switchable between a first state in which the tip side passage 31b is connected to the second chamber 27, and a second state in which the second chamber 27 is connected to the external connection path 63.

[0070] Therefore, in the first state, oil is appropriately supplied to the second chamber 27, while in the second state, oil is appropriately discharged from the second chamber 27. Therefore, the variable displacement oil pump can be controlled to a predetermined hydraulic pressure.

[0071] In the first embodiment, the valve portion 28 of the solenoid valve 13 includes a valve body 39, a spool 40 slidably disposed within the valve body 39, a disk-shaped retainer 41 fixed to the inner periphery of the valve body 39, and a second coil spring 64 disposed between the retainer 41 and the spool 40.

[0072] Generally, a solenoid valve used in a valve timing control device for an internal combustion engine has a valve body, a spool, a valve sleeve, and a coil spring. However, in this embodiment, a disk-shaped retainer 41, which is a smaller part, is used instead of a cylindrical valve sleeve, so that the structure of the solenoid valve 13 can be simplified and the manufacturing cost of the solenoid valve 13 can be reduced.

[0073] Furthermore, in the first embodiment, oil from the main gallery is introduced into the tip side passage 31b, flows radially in the valve body 39, and then flows axially through the axial passage 31c, before being introduced into the introduction passage 31e via the first valve opening 31d.

[0074] If oil were introduced from the tip-side passage to apply hydraulic pressure directly to the spool, there would be a risk that the spool would be affected by hydraulic pressure in the axial direction, which would inhibit stable operation. However, as in the first embodiment, by bypassing hydraulic pressure from the radially outer side of the valve body 39 rather than directly applying hydraulic pressure in the axial direction of the spool 40, the spool 40 can be operated stably, and the solenoid valve 13 can be controlled more precisely.

[0075] In the first embodiment, the solenoid valve 13 has a solenoid portion 29 at the rear end of the valve body 39 which urges the rear end shaft portion 40d of the spool 40 from the rear end of the valve body 39 toward the tip end in response to an electrical signal applied from the outside.

[0076] Therefore, by appropriately controlling the duty ratio D to adjust the oil pressure in the second chamber 27, the oil pressure of the variable displacement oil pump can be controlled steplessly.

[0077] Furthermore, in the first embodiment, the spool 40 has a spool drain hole 40h that opens radially into the rear end shaft portion 40d, and a drain connection passage 40g that connects the spool drain hole 40h to the inside of the second coil spring 64.

[0078] Therefore, air expanded within the spring accommodating portion 65 during operation of the internal combustion engine is discharged to the outside via the drain connection passage 40g and the spool drain hole 40h. As a result, the expansion and contraction of the second coil spring 64 is not inhibited by the expanded air, and the solenoid valve 13 can be efficiently operated by only the hydraulic pressure Fp, the pressing force Fr of the rod 50, and the spring force Fs2 of the second coil spring 64.

[0079] In the first embodiment, the volume of the second chamber 27 increases when the cam ring 6 moves in a direction in which the flow rate of the oil discharged from the discharge port 24 increases.

[0080] When second chamber 27 is configured in this manner, the spring force of first coil spring 7 acts in the same direction as the oil pressure in second chamber 27 biases cam ring 6. For this reason, if the contribution rate of the oil pressure to the operation of cam ring 6 is increased, first coil spring 7 can be made smaller and the variable displacement oil pump can be simplified.

[0081] In addition, by using a small first coil spring 7 and controlling the movement of the cam ring 6 mainly by the oil pressure in the second chamber 27, the minimum discharge pressure of the variable displacement oil pump can be set low, thereby improving the fuel consumption rate of the internal combustion engine.

[0082] Furthermore, in the first embodiment, when viewed from a direction along the rotational axis O1 of the pump component, the solenoid valve 13 is arranged so that the tip of the valve portion 28 overlaps with a portion of the cam ring 6 provided between the first chamber 26 and the second chamber 27, and the solenoid portion 29 on the opposite side of the tip of the valve portion 28 is provided outside the second chamber 27.

[0083] In this arrangement of the solenoid valve 13 and the cam ring 6, the distance between the solenoid valve 13 and the second chamber 27 is shorter than when the solenoid valve 13 is arranged to the side of the cam ring 6. Therefore, the hydraulic response can be improved when supplying oil to the second chamber 27 or when discharging oil from the second chamber 27.

[0084] In the first embodiment, the connection passage 31 is disposed between the pivot pin 22 of the cam ring 6 and the drive shaft 3 of the pump constituent body when viewed from a direction along the rotation axis O1 of the pump constituent body.

[0085] Therefore, compared to when the connecting passage 31 is positioned on the opposite side of the pivot pin 22 across the drive shaft 3, the connecting passage 31 is connected to the first and second chambers 26, 27 over a short distance via the first and second chamber oil passages 32, 34, allowing oil to be supplied to the first chamber 26 and oil to be supplied and discharged from the second chamber 27 quickly.

[0086] Furthermore, in the first embodiment, the first chamber oil passage 32 opens radially on the pivot pin 22 side of the cam ring 6, i.e., on the rocking fulcrum side, of the first chamber 26 when viewed from the direction along the rotation axis O1 of the pump constituent body, and the second chamber oil passage 34 opens radially on the rocking fulcrum side of the cam ring 6, of the second chamber 27 when viewed from the direction along the rotation axis O1 of the pump constituent body. At this time, the connection passage 31 is formed at a position that connects the first chamber 26 and the second chamber 27 by the shortest distance, when viewed from the direction along the rotation axis O1 of the pump constituent body.

[0087] Therefore, the connection passage 31 and the first and second chambers 26, 27 are connected via the first and second chamber oil passages 32, 34 in the shortest distance, and the supply of oil to the first chamber 26 and the supply and drainage of oil to the second chamber 27 can be performed more quickly.

[0088] In the first embodiment, an inlet 33 through which oil is introduced from the main gallery is provided between the first chamber 26 and the connection passage 31.

[0089] Therefore, compared to when the inlet 33 is provided in the connection passage 31, the distance between the inlet 33 and the first chamber 26 can be made shorter, and oil can be supplied to the first chamber 26 more efficiently.

[0090] [Second embodiment] FIG. 8 is a cross-sectional view of a solenoid valve 13 according to the second embodiment.

[0091] In the second embodiment, unlike the first embodiment, the solenoid valve 13 has a configuration similar to that of a solenoid valve generally used in a valve timing control device for an internal combustion engine, and the valve portion 28 has a valve portion sleeve 53.

[0092] The valve portion 28 includes a cylindrical valve body 39, a cylindrical valve sleeve 53 fixed to the inner periphery of the tip of the valve body 39, a spool 40 disposed within the valve body 39 and slidably mounted on the inner periphery of the valve body 39 and the outer periphery of the valve sleeve 53, and a second coil spring 64 provided between the spool 40 and the valve sleeve 53.

[0093] The valve body 39 includes a hole 39j, four second chamber openings 39k, an external connection passage 63, and four air drain holes 39m.

[0094] Hole 39j is open at tip 39h and extends from tip 39h to rear end 39i. Hole 39j opens into a connection passage inlet (not shown) provided in the housing body. An annular recess 39f is formed on the inner circumferential surface of hole 39j into which the outer circumferential portion of retaining ring 54 for fixing valve sleeve 53 is fitted.

[0095] The second chamber openings 39k are provided at circumferentially equally spaced positions on the rear end portion 39i side of the valve body 39 and radially penetrate the valve body 39. The second chamber openings 39k communicate with a second chamber oil passage (not shown) that is connected to the second chamber of the variable displacement oil pump.

[0096] The external connection passage 63 radially penetrates the valve body 39 between the second chamber opening 39k and the rear end portion 39i. The external connection passage 63 communicates with the outside, for example an oil pan, where the pressure is lower than the pressure of the oil discharged from the discharge port 24.

[0097] The air drain holes 39m are provided at equally spaced circumferential positions near the tip end 39h and radially penetrate the valve body 39. The air drain holes 39m communicate between a spring accommodating portion 65 that accommodates a second coil spring 64 and the outside.

[0098] The valve sleeve 53 has a cylindrical main body 53a and an annular flange 53b that protrudes radially outward from the outer periphery of one axial end of the main body 53a.

[0099] The main body 53a has a sleeve axial opening 53c facing the hole 39j, and four sleeve radial openings 53d that are provided closer to the rear end 39i than the sleeve axial opening 53c and penetrate the main body 53a in the radial direction at equally spaced positions in the circumferential direction. Oil is guided to the sleeve radial openings 53d from inside the main body 53a.

[0100] The flange portion 53b is fixed to the step portion 39e by being pressed toward the rear end portion 39i by the retaining ring 54 while being in contact with the step portion 39e provided in the hole portion 39j of the valve body 39. In a state in which the flange portion 53b is fixed to the step portion 39e as shown in Fig. 8, the main body portion 53a extends along the axial direction of the valve body 39 from the base portion where the flange portion 53b joins with the main body portion 53a to an axial position corresponding to the second chamber opening 39k. The surface 53e of the flange portion 53b adjacent to the main body portion 53a becomes the surface with which one end of the second coil spring 64 elastically comes into contact.

[0101] The spool 40 has a large diameter portion 40a, an intermediate shaft portion 40b, a medium diameter portion 40c, and a rear end shaft portion 40d. As shown in Fig. 8, a central hole 39n is formed inside the large diameter portion 40a, the intermediate shaft portion 40b, and the medium diameter portion 40c, and extends from one axial end of the large diameter portion 40a to the other axial end of the medium diameter portion 40c. The diameter of the central hole 39n is set to a size corresponding to the outer diameter of the valve sleeve 53, so that the inner peripheral surface of the central hole 39n is slidable against the outer peripheral surface of the valve sleeve 53.

[0102] The large diameter portion 40a is provided between the sleeve axial opening 53c and the sleeve radial opening 53d so as to extend from the front end 39h side toward the rear end 39i side of the valve body 39.

[0103] The intermediate shaft portion 40b has a spool radial opening 40m provided at a position axially adjacent to the large diameter portion 40a. The spool radial opening 40m opens into the central hole portion 39n of the intermediate shaft portion 40b and communicates with a sleeve radial opening 53d of the valve portion sleeve 53. Oil that has passed through the main body portion 53a and the sleeve radial opening 53d is introduced into the spool radial opening 40m. The oil introduced into the spool radial opening 40m is introduced into the second chamber (not shown) via the introduction passage 31e, the second chamber opening 39k, and the second chamber oil passage (not shown).

[0104] As shown in FIG. 8, when the second coil spring 64 is in an expanded state, the medium diameter portion 40c is disposed between the external connection passage 63 and the second chamber opening 39k.

[0105] The second coil spring 64 is disposed in a compressed state between the axial end face 40n of the large diameter portion 40a and the face 53e of the flange portion 53b of the valve portion sleeve 53 so as to urge the spool 40 toward the rear end portion 39i of the valve body 39.

[0106] [Effects of the second embodiment] In the second embodiment, the valve portion 28 of the solenoid valve 13 includes a valve body 39, a valve portion sleeve 53 fixed to the inner circumference of the valve body 39, a spool 40 slidably provided on the inner circumference of the valve body 39 and the outer circumference of the valve portion sleeve 53, and a second coil spring (spool biasing member) 64 provided between the spool 40 and the valve portion sleeve 53.

[0107] Therefore, by providing a sleeve radial direction opening 53d in the main body portion 53a of the valve sleeve 53 and appropriately communicating it with the second chamber opening 39k, the hydraulic pressure introduced into the second chamber 27 can be controlled more precisely.

[0108] In the second embodiment, the solenoid valve 13 has a solenoid portion 29 at the rear end 39i of the valve body 39, which urges the rear end shaft portion 40d of the spool 40 from the rear end 39i of the valve body 39 toward the tip end 39h in response to an electrical signal applied from the outside.

[0109] Therefore, even in the solenoid valve 13 of the second embodiment having the valve portion sleeve 53, the oil pressure of the variable displacement oil pump can be controlled steplessly by appropriately controlling the duty ratio D to adjust the oil pressure in the second chamber.

[0110] [Third embodiment] Fig. 9 is a front view of the variable displacement oil pump of the third embodiment showing the solenoid valve 13 in a non-operating state, and Fig. 10 is a front view of the variable displacement oil pump of the third embodiment showing the solenoid valve 13 in an operating state. Note that in Figs. 9 and 10, the solenoid valve 13 is shown as being disposed radially outward of the cam ring 6 to make the flow of oil easier to understand, but in reality, the valve portion 28 of the solenoid valve 13 is disposed so as to face a partial area of ​​the cam ring 6 when viewed from the direction along the rotation axis O1 of the pump constituent body.

[0111] In the third embodiment, the cam ring 6 does not swing around a pivot pin but moves linearly, and the pump component is disposed so that the inner circumferential center of the cam ring 6 and the rotation axis O1 of the drive shaft 3 of the pump component are eccentric.

[0112] The cam ring 6 has a first protrusion 55 protruding radially outward from the outer periphery of the cam ring 6, and a second protrusion 56 provided on the radially opposite side of the first protrusion 55 and protruding from the outer periphery of the cam ring 6.

[0113] The first protrusion 55 is slidably disposed between two side walls 57a, 57a of a first recess 57 provided in the inner circumferential wall of the pump accommodation chamber 1a. Here, the sliding direction of the first protrusion 55 is along the longitudinal direction of the solenoid valve 13. Between the tip of the first protrusion 55 and the bottom of the first recess 57, a first chamber 26 is formed into which oil is introduced from the main gallery.

[0114] The second protruding portion 56 is disposed slidably between two side walls 58a, 58a of a second recessed portion 58 provided in the inner circumferential wall of the pump accommodation chamber 1a. Here, the sliding direction of the second protruding portion 56 is the direction along the longitudinal direction of the solenoid valve 13, similar to the first protruding portion 55. Between the second protruding portion 56 and the bottom of the second recessed portion 58, a second chamber 27 is formed into which oil from the main gallery can be introduced via the solenoid valve 13.

[0115] Further, a third coil spring 59 compressed by a predetermined set load W3 is provided between the second protruding portion 56 and the bottom of the second recessed portion 58. The third coil spring 59 moves the cam ring 6 linearly toward the first chamber 26 side against the hydraulic pressure in the first chamber 26 by the combined force of the biasing force of the third coil spring 59 and the hydraulic pressure in the second chamber 27.

[0116] As shown in FIG. 9, when the solenoid valve 13 is in a non-operating state, the oil in the main gallery is guided through the first chamber oil passage 32, the connecting passage inlet portion 31a, the tip side passage 31b, the axial passage 31c, and the first valve opening 31d to the introduction passage 31e, and then from the introduction passage 31e to the second chamber 27 via the second valve opening 31f and the second chamber oil passage 34.

[0117] 10, when the solenoid valve 13 is in the operating state, the oil in the main gallery is guided to the introduction passage 31e via the first chamber oil passage 32, the connection passage inlet 31a, the tip side passage 31b, the axial passage 31c, and the first valve opening 31d. At the same time, the oil in the second chamber 27 is discharged to the outside via the second chamber oil passage 34, the second valve opening 31f, the discharge passage 60, the third valve opening 62, and the external connection passage 63.

[0118] [Effects of the third embodiment] In the third embodiment, in a variable displacement oil pump, a cam ring 6 does not swing about a pivot pin but moves linearly.

[0119] With a variable displacement oil pump having such a configuration, similarly to the first embodiment, it is possible to easily form an oil passage for guiding oil from the main gallery to the first chamber 26 or the second chamber 27, and to suppress deterioration of sealing performance. Furthermore, it is possible to reduce the size of the variable displacement oil pump, and to reduce the manufacturing costs associated with the pump.

[0120] [Fourth embodiment] Fig. 11 is a front view of the variable displacement oil pump of the fourth embodiment showing the solenoid valve 13 in a non-operating state, and Fig. 12 is a front view of the variable displacement oil pump of the fourth embodiment showing the solenoid valve 13 in an operating state. Note that in Figs. 11 and 12, the solenoid valve 13 is shown as being disposed radially outward of the cam ring 6 to make the oil flow easy to understand, but in reality, the valve portion 28 of the solenoid valve 13 is disposed so as to face a partial area of ​​the cam ring 6 when viewed from the direction along the rotation axis O1 of the pump constituent body.

[0121] In the variable displacement oil pump of the fourth embodiment, unlike the first embodiment, the second chamber 27 is disposed above the cam ring reference line M and is disposed adjacent to the first chamber 26 in the circumferential direction. More specifically, as shown in Figs. 11 and 12, only the first and second seal members 16 and 18 are present as the seal members, and both the first and second seal members 16 and 18 are disposed above the cam ring reference line M. The first chamber 26 is formed between the pivot pin 22 and the first seal member 16, and the second chamber 27 is formed between the first seal member 16 and the second seal member 18. The second chamber 27 is configured to have a larger volume when the cam ring 6 moves in a direction in which the flow rate of the oil discharged from the discharge port 24 decreases.

[0122] Furthermore, the spool 40 of the solenoid valve 13 has an annular rear-end shank expanded diameter portion 40o provided at the other axial end of the rear-end shank 40d of the spool 40. The rear-end shank expanded diameter portion 40o is provided at a position facing the medium diameter portion 40c in the axial direction of the spool 40, and has an outer diameter equal to the outer diameter of the medium diameter portion 40c.

[0123] 11, when the solenoid valve 13 is in a non-operating state, the oil in the main gallery is guided to the introduction passage 31e via the first chamber oil passage 32, the connection passage inlet 31a, the tip side passage 31b, the axial passage 31c, and the first valve opening 31d. At the same time, the oil in the second chamber 27 is discharged to the outside via the second chamber oil passage 34, the second valve opening 31f, the discharge passage 60, the third valve opening 62, and the external connection passage 63.

[0124] Also, as shown in FIG. 12, when the solenoid valve 13 is in the operating state, the oil in the main gallery is guided to the second chamber 27 via the first chamber oil passage 32, the connecting passage inlet portion 31a, the tip side passage 31b, the axial passage 31c, the first valve opening 31d, the discharge passage 60, the second valve opening 31f, and the second chamber oil passage 34.

[0125] [Effects of the fourth embodiment] In the fourth embodiment, the second chamber 27 is disposed above the cam ring reference line M and is disposed adjacent to the first chamber 26 in the circumferential direction.

[0126] With a variable displacement oil pump having such a configuration, similarly to the first embodiment, it is possible to easily form an oil passage for guiding oil from the main gallery to the first chamber 26 or the second chamber 27, and to suppress deterioration of sealing performance. Furthermore, it is possible to reduce the size of the variable displacement oil pump, and to reduce the manufacturing costs associated with the pump.

[0127] In each of the above embodiments, an example has been disclosed in which the variable displacement oil pump has the first chamber 26 and the second chamber 27. However, in the case where the variable displacement oil pump has only the first chamber, naturally, by arranging a solenoid valve near the first chamber, the solenoid valve seals the first chamber oil passage, and there is no need to bypass the oil passage.

Claims

1. a housing having a pump chamber; An adjustment member movably provided inside the pump accommodating chamber; a pump constituent provided within the adjusting member, the pump constituent being rotationally driven to discharge oil drawn in from a suction portion from a discharge portion, and a flow rate of the oil discharged from the discharge portion changing when the adjusting member moves; a first chamber formed between the pump accommodating chamber and the adjusting member in a radial direction relative to a rotation axis of the pump constituent body, the first chamber being configured to guide the oil discharged from the discharge portion and to have a volume that increases when the adjusting member moves in a direction in which a flow rate of the oil discharged from the discharge portion decreases; a second chamber formed between the pump accommodating chamber and the adjusting member in a radial direction with respect to a rotation axis of the pump constituent body, the second chamber into which the oil discharged from the discharge portion is guided; a connecting passage formed linearly at a position adjacent to the first chamber and the second chamber when viewed from a direction along a rotation axis of the pump constituent body, and through which oil that has passed through a main gallery is guided; a first chamber oil passage that branches in a direction intersecting the longitudinal direction of the connection passage and is connected to the first chamber; a control valve accommodating portion connected to the connection passage and formed with a diameter larger than that of the connection passage, the control valve accommodating portion having a bottom portion at which the connection passage opens, a control valve accommodating port opening at a position opposite to the bottom portion, and an external connection passage communicating with the outside having a pressure lower than the pressure of the oil discharged from the discharge portion; a second chamber oil passage branching from the control valve accommodating portion in a direction intersecting the longitudinal direction of the connection passage and connected to the second chamber; a control valve inserted into the control valve accommodating portion from the control valve accommodating port toward the bottom of the control valve accommodating portion, the control valve connecting the second chamber oil passage to a tip side passage formed between the bottom of the control valve accommodating portion and a tip of the control valve; A variable displacement oil pump.

2. 2. The variable displacement oil pump according to claim 1, A variable displacement oil pump characterized in that it switches between a first state in which the tip side passage is connected to the second chamber and a second state in which the second chamber is connected to the external connection path.

3. 2. The variable displacement oil pump according to claim 1, The control valve is a fixing portion that is provided at a position facing a bottom portion of the control valve accommodating portion at which the connection passage opens, and that forms the tip side passage between itself and the bottom portion of the control valve accommodating portion; a cylindrical valve body accommodated in the control valve accommodating portion and having the fixed portion fixed to an inner circumferential surface, the valve body having: a recessed portion that is connected to the tip-side passage between an inner periphery of the control valve accommodating portion and an outer periphery of the fixed portion and forms an axial passage; a first valve opening that is provided in the recessed portion and passes through the outer periphery and inner periphery of the valve body; and a second valve opening that is provided on a rear end side opposite to the tip end of the first valve opening, passes through the outer periphery and inner periphery of the valve body, and faces the second chamber oil passage; a spool accommodated in an inner periphery of the valve body, the spool having: a large diameter portion sliding against the inner periphery of the valve body between the first valve opening and the fixed portion; an intermediate shaft portion provided adjacent to the large diameter portion and forming an introduction passage connecting to the axial passage via the first valve opening between the large diameter portion and the inner periphery of the valve body; a medium diameter portion provided opposite to the large diameter portion and sliding against an inner periphery of the valve body located on the rear end side from the second valve opening, the medium diameter portion having a smaller diameter than the large diameter portion and a larger diameter than the intermediate shaft portion; and a rear end shaft portion provided closer to the rear end than the intermediate shaft portion; a spring provided on an inner periphery of the valve body between the fixed portion and the spool, the spring biasing the spool toward the rear end portion; A variable displacement oil pump comprising:

4. 4. The variable displacement oil pump according to claim 3, a solenoid unit at a rear end of the valve body that urges a rear end shaft portion of the spool from the rear end toward the tip end in response to an electrical signal applied from the outside.

5. 4. The variable displacement oil pump according to claim 3, the spool has a spool drain hole that opens radially into the rear end shaft portion, and a drain connection passage that connects the spool drain hole and an inside of the spring, a third valve opening provided in the valve body in communication with a discharge passage provided on an outer periphery of the spool and facing the external connection passage,

6. 2. The variable displacement oil pump according to claim 1, The control valve is a valve body formed in a cylindrical shape, the valve body having a hole extending from a tip end portion to a rear end portion opposite the tip end portion and opening to the tip end portion, a second chamber opening provided in a radial direction of the valve body and communicating with the second chamber oil passage, and an external connection passage communicating with the outside having a lower pressure than the pressure of the oil discharged from the discharge portion; a sleeve fixed to the tip end side inside the valve body and extending from the tip end toward the rear end, the sleeve having a sleeve axial opening facing the hole and a sleeve radial opening provided radially on the rear end side of the sleeve axial opening; a spool disposed between an inner periphery of the valve body and an outer periphery of the sleeve, the spool having, from the tip end to the rear end, a large diameter portion provided between the sleeve axial opening and the sleeve radial opening, sliding against the inner periphery of the valve body, an intermediate shaft portion provided adjacent to the large diameter portion and forming an introduction passage between the inner periphery of the valve body, a spool radial opening opening that opens into the intermediate shaft portion and communicates with the sleeve radial opening, a medium diameter portion provided opposite to the large diameter portion, between the external connection passage and the second chamber opening, the medium diameter portion being larger than the intermediate shaft portion but smaller than the large diameter portion, sliding against the inner periphery of the valve body, and a rear end shaft portion provided adjacent to the medium diameter portion and forming a discharge passage between the inner periphery of the valve body a spool biasing member that biases the spool toward the rear end; A variable displacement oil pump comprising:

7. 7. The variable displacement oil pump according to claim 6, a solenoid unit at a rear end of the valve body that urges a rear end shaft portion of the spool from the rear end toward the tip end in response to an electrical signal applied from the outside.

8. 2. The variable displacement oil pump according to claim 1, a second chamber having a volume increased when the adjusting member moves in a direction in which a flow rate of the oil discharged from the discharge portion increases, the ...

9. 9. The variable displacement oil pump according to claim 8, a pump component including an inner circumferential center of the adjustment member and a rotation axis of a drive shaft of the pump component that are eccentrically disposed, and the adjustment member oscillates around a fulcrum.

10. 10. The variable displacement oil pump according to claim 9, a control valve having a front end that overlaps with the adjustment member provided between the first chamber and the second chamber when viewed from a direction along the rotation axis, and a rear end on the opposite side to the front end that is located outside the second chamber.

11. 10. The variable displacement oil pump according to claim 9, a connecting passage disposed between a pivot point of the adjustment member and a drive shaft of the pump component when viewed from a direction along the rotation axis of the variable displacement oil pump.

12. 12. The variable displacement oil pump according to claim 11, the first chamber oil passage opens at a pivot point side of the first chamber in the radial direction when viewed from a direction along the rotation axis, A variable displacement oil pump, characterized in that the second chamber oil passage opens on the fulcrum side of the second chamber in the radial direction when viewed from a direction along the rotation axis.

13. 12. The variable displacement oil pump according to claim 11, A variable displacement oil pump, characterized in that an inlet through which oil is introduced from the main gallery is provided between the first chamber and the connecting passage.

14. 9. The variable displacement oil pump according to claim 8, The pump constituent body is disposed such that a center of an inner circumference of the adjustment member and a rotation axis of a drive shaft of the pump constituent body are eccentric to each other, A variable displacement oil pump, wherein the adjustment member moves linearly.

15. 2. The variable displacement oil pump according to claim 1, a second chamber having a volume increased when the adjusting member moves in a direction in which a flow rate of the oil discharged from the discharge portion decreases;

16. a housing having a pump chamber; An adjustment member movably provided inside the pump accommodating chamber; a pump constituent provided within the adjusting member, the pump constituent being rotationally driven to discharge oil drawn in from a suction portion from a discharge portion, and a flow rate of the oil discharged from the discharge portion changing when the adjusting member moves; a first chamber formed between the pump accommodating chamber and the adjusting member in a radial direction relative to a rotation axis of the pump constituent body, the first chamber being configured to guide the oil discharged from the discharge portion and to have a volume that increases when the adjusting member moves in a direction in which a flow rate of the oil discharged from the discharge portion decreases; a second chamber formed between the pump accommodating chamber and the adjusting member in a radial direction with respect to a rotation axis of the pump constituent body, the second chamber into which the oil discharged from the discharge portion is guided; an oil passage provided at a position adjacent to the first chamber and the second chamber when viewed in a direction along the rotation axis of the pump constituent body, through which oil that has passed through a main gallery from the first chamber side is guided, the oil passage having: a straight oil passage portion formed at a position that connects the first chamber and the second chamber at the shortest distance when viewed in a direction along the rotation axis of the pump constituent body; a first chamber oil passage branching off from the straight oil passage portion and connected to the first chamber; a second chamber oil passage branching off from the straight oil passage portion and connected to the second chamber; and an external connection passage branching off from the straight oil passage portion and connected to the outside, the external connection passage having a pressure lower than the pressure of the oil discharged from the discharge portion; a control valve provided on the straight oil passage portion, the control valve connecting the second chamber oil passage to a tip side passage provided at a tip portion of the control valve; A variable displacement oil pump.

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