Vane pump

Abstract

A vane pump (100) is provided with: a first suction port (51) that guides hydraulic oil from a suction passage (11) to a pump chamber (6); a first connection passage (16) that connects the suction passage (11) and the first suction port (51); a second suction port (52) that guides a working fluid from the suction passage (11) to the pump chamber (6); a second connection passage (17) that connects the suction passage (11) and the second suction port (52); an adjustment mechanism that adjusts the pressure or flow rate of the hydraulic oil discharged from the pump chamber (6) to a first discharge passage (12); and a return passage through which a surplus fluid discharged from the adjustment mechanism is guided. The first connection passage (16) and the second connection passage (17) branch from the suction passage (11) to opposite sides across of the rotary shaft of a rotor (2). The return passage (18) guides the surplus fluid discharged from the adjustment mechanism to the second suction port (52) from a location different from that of the second connection passage (17).

Description

vane pump

[0001] The present invention relates to a vane pump.

[0002] JP2001-263266A discloses a vane pump configured to suck hydraulic oil introduced into a suction passage through first and second suction ports and discharge the hydraulic oil from first and second discharge ports.

[0003] In the vane pump described in JP2001-263266A, hydraulic oil introduced into a suction passage is branched and introduced into first and second suction ports.

[0004] In the vane pump described in JP2001-263266A, when the pump rotates at a high rotational speed, the shape and resistance of the flow path may cause an insufficient amount of hydraulic oil to be sucked into either the first or second suction port, which may result in cavitation.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a vane pump that can prevent the amount of suction of working fluid from becoming insufficient even when driven at a high rotational speed.

[0006] The present invention provides a pump pump comprising: a rotor that is driven to rotate; a plurality of vanes that are provided so as to be capable of reciprocating radially relative to the rotor; a cam ring having an inner peripheral cam surface along which the tip ends of the vanes slide as the rotor rotates; a body having an accommodating recess that accommodates the rotor and the cam ring; a pump chamber defined by the rotor, the cam ring, and adjacent vanes; a suction passage that introduces working fluid from the outside into the body; a first suction port that introduces working fluid from the suction passage to the pump chamber; a first connecting passage that connects the suction passage and the first suction port; a first discharge passage that discharges working fluid that has been sucked into the pump chamber from the first suction port; and a suction passage. a second suction port that guides the working fluid from the suction passage to the pump chamber, a second connecting passage that connects the suction passage and the second suction port, a second discharge passage that discharges the working fluid sucked into the pump chamber from the second suction port from the pump chamber, an adjustment mechanism that adjusts the pressure or flow rate of the working fluid discharged from the pump chamber to the first discharge passage, and a return passage to which excess fluid discharged from the adjustment mechanism is guided, wherein the first connecting passage and the second connecting passage branch off from the suction passage so as to head in opposite directions across the rotor's rotation axis, and the return passage guides the excess fluid discharged from the adjustment mechanism to the second suction port from a location different from the second connecting passage.

[0007] Fig. 1 is a cross-sectional view of a vane pump according to an embodiment of the present invention. Fig. 2 is a diagram showing the internal structure of the vane pump with the cover and cover-side side plate removed. Fig. 3 is a perspective view of the cover-side side plate, cam ring, and body-side side plate assembled. Fig. 4 is a plan view of the body-side side plate.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] A vane pump 100 according to an embodiment of the present invention is used as a fluid pressure supply source for a fluid pressure device mounted on a vehicle, such as a power steering device, a transmission, etc. The working fluid is hydraulic oil or other water-soluble alternative liquid.

[0010] Fig. 1 is a cross-sectional view of the vane pump 100. Fig. 2 is a diagram showing the internal structure of the vane pump 100, with the cover member 20 and the cover-side side plate 30 removed. Fig. 3 is a perspective view of the cover-side side plate 30, the cam ring 4, and the body-side side plate 40 assembled together. Fig. 4 is a plan view of the body-side side plate 40.

[0011] As shown in Figures 1 and 2, the vane pump 100 comprises a rotor 2 connected to a drive shaft 1 and driven to rotate, a plurality of slits 2a each having an opening and formed radially on the outer periphery of the rotor 2, a plurality of vanes 3 slidably inserted into each slit 2a and arranged to be able to reciprocate radially relative to the rotor 2, a cam ring 4 that houses the rotor 2 and has an inner cam surface 4a against which the tip ends of the vanes 3 slide as the rotor 2 rotates, a body 10 formed with an accommodating recess 10a that accommodates these components, and a cover member 20 attached to the body 10 and closing the accommodating recess 10a.

[0012] 2, a back pressure chamber 5 to which the discharge pressure of the vane pump 100 is introduced is defined at the base end of the slit 2a. The vanes 3 are pressed in a direction out of the slit 2a by the pressure in the back pressure chamber 5 and the centrifugal force generated by the rotation of the rotor 2, and their tips come into contact with the inner peripheral cam surface 4a of the cam ring 4. As a result, a plurality of pump chambers 6 are defined inside the cam ring 4 by the outer peripheral surface of the rotor 2, the inner peripheral cam surface 4a of the cam ring 4, and adjacent vanes 3.

[0013] The cam ring 4 is an annular member with an inner peripheral cam surface 4a having a generally elliptical shape, and has a suction region where the volume of the pump chamber 6 expands with rotation of the rotor 2, and a discharge region where the volume of the pump chamber 6 contracts. Each pump chamber 6 expands and contracts with rotation of the rotor 2. The vane pump 100 is a so-called balanced vane pump in which the cam ring 4 has two suction regions and two discharge regions. The cam ring 4 is formed with a pair of through holes 4b through which the pins 60 are inserted, and notches 4c, 4d that communicate between the outside and inside of the cam ring 4 on both end faces at positions corresponding to the two suction regions.

[0014] As shown in FIG. 1, the body 10 is provided with a suction passage 11 that communicates with a tank (not shown) and guides the hydraulic oil stored in the tank into the vane pump 100, and a first discharge passage 12 and a second discharge passage 13 that discharge the hydraulic oil discharged from the pump chamber 6 to the outside.

[0015] The body 10 is provided with a relief valve 90 as an adjustment mechanism for adjusting the pressure of the hydraulic oil discharged to the first discharge passage 12. The hydraulic oil discharged from the relief valve 90 passes through a return passage 14 as a second return passage formed in the body 10 and is returned to first and second suction ports 51, 52, which will be described later. The return passage 14 is provided in an area opposite the suction passage 11, with the first and second suction ports 51, 52 sandwiched between them (see FIG. 1 ).

[0016] 1, the cover member 20 is formed with a through hole 21 that supports the drive shaft 1 via a sleeve 70. The cover member 20 is fixed to the body 10 with bolts (not shown).

[0017] The vane pump 100 further includes a cover-side side plate 30 as a side member that abuts against one end faces (left side in FIG. 1 ) of the rotor 2 and the cam ring 4, and a body-side side plate 40 as a side member that abuts against the other end faces (right side in FIG. 1 ) of the rotor 2 and the cam ring 4.

[0018] The cover-side side plate 30 and the body-side side plate 40 are arranged to sandwich the rotor 2 and the cam ring 4. The pump chamber 6 is sealed by the cover-side side plate 30 and the body-side side plate 40 sandwiching both end faces of the rotor 2 and the cam ring 4. The cover-side side plate 30, the body-side side plate 40, the rotor 2, and the vanes 3 are housed in the housing recess 10a of the body 10 so as to be in sliding contact with each other.

[0019] 3, the cover-side side plate 30 is formed by cutting out a portion of its outer edge, and is provided with suction recesses 31 and 32 that guide hydraulic oil into the pump chamber 6, a through hole 33 through which the drive shaft 1 is inserted, and a through hole 34 through which the pin 60 is inserted. The suction recesses 31 and 32 are provided at positions that are approximately symmetrical with respect to the drive shaft 1.

[0020] In this embodiment, a first suction port 51 is formed by the suction recess 31 formed in the cover-side side plate 30 and the notch 4c formed in the cam ring 4, and a second suction port 52 is formed by the suction recess 32 formed in the cover-side side plate 30 and the notch 4d formed in the cam ring 4. A third suction port 53 is formed by the suction recess 45 formed in the body-side side plate 40 and the notch 4e formed so as to open on the end face of the cam ring 4 opposite to the end face where notch 4c opens. Although not shown, a fourth suction port is formed by the suction recess 46 (see FIG. 4) formed in the body-side side plate 40 and the notch formed so as to open on the end face of the cam ring 4 opposite to the end face where notch 4d opens.

[0021] In the vane pump 100 of this embodiment, the first suction port 51, the second suction port 52, the third suction port 53, and the fourth suction port are not directly connected to the suction passage 11. In other words, the first suction port 51, the second suction port 52, the third suction port 53, and the fourth suction port open at positions offset from the suction passage 11 in the circumferential direction of the cam ring 4.

[0022] As shown in Figure 4, the body-side side plate 40 has a sliding surface 41 with which the other end face of the rotor 2 slides, a pair of first and second discharge ports 42 and 43 formed on the sliding surface 41 so as to correspond to the two discharge areas, respectively, and which discharge the hydraulic oil from the pump chamber 6, a through hole 44 through which the drive shaft 1 is inserted, suction recesses 45 and 46 formed by recessing part of the outer edge portion and which guide the hydraulic oil into the pump chamber 6, a pair of through holes 47 through which the pin 60 is inserted, and back pressure grooves 48 formed on the sliding surface 41 and spaced apart in the circumferential direction.

[0023] The first discharge port 42 and the second discharge port 43 are provided at positions symmetrical with respect to the through hole 44. The first discharge port 42 and the second discharge port 43 are formed in an arc shape centered on the through hole 44, and are formed to penetrate the body-side side plate 40.

[0024] The suction recesses 45, 46 are formed on the sliding surface 41 so as to correspond to the two suction regions. The outer peripheral ends of the suction recesses 45, 46 reach the outer peripheral surface of the body-side side plate 40 and are formed in a concave shape that opens radially outward.

[0025] The back pressure groove 48 is formed in a groove shape that opens to the sliding contact surface 41. The back pressure groove 48 is formed in an arc shape centered on the through hole 44, and communicates with a plurality of back pressure chambers 5 that overlap with the back pressure groove 48. The discharge side hydraulic oil is guided to the back pressure groove 48 through a flow path (not shown).

[0026] As shown in FIG. 2, the vane pump 100 further includes a first connecting passage 16 connecting the suction passage 11 and the first suction port 51, a second connecting passage 17 connecting the suction passage 11 and the second suction port 52, and a return passage 18 serving as a first return passage, one end of which is connected to the first suction port 51 and the other end of which is connected to the second suction port 52.

[0027] The first connecting passage 16 , the second connecting passage 17 , and the return passage 18 are formed between the inner peripheral surface of the accommodation recess 10 a of the body 10 and the outer peripheral surface of the cover-side side plate 30 .

[0028] The first connecting passage 16 and the second connecting passage 17 branch off from the suction passage 11 and are provided along the outer peripheral surface of the cover-side side plate 30 so as to extend in opposite directions across the drive shaft 1 .

[0029] The return passage 18 is provided on the opposite side of the first connection passage 16 and the second connection passage 17, across the first suction port 51 and the second suction port 52. That is, in the vane pump 100, the first connection passage 16, the second connection passage 17, and the return passage 18 are formed side by side in the circumferential direction between the inner circumferential surface of the accommodation recess 10a of the body 10 and the outer circumferential surface of the cover-side side plate 30.

[0030] Next, the operation of the vane pump 100 will be described.

[0031] The drive shaft 1 is driven to rotate by the power of a drive device such as an engine (not shown), thereby rotating the rotor 2. As the rotor 2 rotates, the pump chamber 6 expands as it passes through the two suction regions. As a result, hydraulic oil in the tank is sucked into the pump chamber 6 through the suction passage 11, the first and second connecting passages 16 and 17, and the first and second suction ports 51 and 52. As the rotor 2 rotates, the pump chamber 6 contracts toward the discharge region. The hydraulic oil in the pump chamber 6 in one discharge region is supplied to a hydraulic device (not shown) through the first discharge port 42 and the first discharge passage 12, while the hydraulic oil in the pump chamber 6 in the other discharge region is supplied to a hydraulic device (not shown) through the second discharge port 43 and the second discharge passage 13. In the vane pump 100, each pump chamber 6 repeatedly draws in and discharges hydraulic oil twice during one rotation of the rotor 2. In the vane pump 100 of this embodiment, the first discharge passage 12 and the second discharge passage 13 do not merge, but supply hydraulic oil to different hydraulic devices.

[0032] A portion of the hydraulic oil discharged to the first and second discharge passages 12, 13 is supplied to the back pressure chamber 5 through a flow path not shown. As a result, the vane 3 is pressed toward the inner circumferential cam surface 4a of the cam ring 4. Therefore, the vane 3 is urged in a direction protruding from the slit 2a by the fluid pressure in the back pressure chamber 5 pressing against the base end 3b and by the centrifugal force acting in conjunction with the rotation of the rotor 2. As a result, the tip end 3a of the vane 3 rotates while making sliding contact with the inner circumferential cam surface 4a of the cam ring 4, so that the hydraulic oil in the pump chamber 6 is discharged from the pump chamber 6 without leaking between the tip end 3a of the vane 3 and the inner circumferential cam surface 4a of the cam ring 4.

[0033] In the vane pump 100, hydraulic oil is drawn from the suction passage 11 through the first and second connecting passages 16 and 17 to the first and second suction ports 51 and 52 as shown by the dotted arrows in Figure 2. While hydraulic oil drawn from the first suction port 51 is drawn in along the rotational direction of the rotor 2, hydraulic oil drawn from the second suction port 52 is drawn by turning back in the rotational direction of the rotor 2. For this reason, hydraulic oil drawn from the second suction port 52 has a greater suction resistance than hydraulic oil drawn from the first suction port 51. In other words, the suction of hydraulic oil from the second suction port 52 side is likely to be at a disadvantage compared to the suction of hydraulic oil from the first suction port 51 side.

[0034] For this reason, for example, if the flow rate of hydraulic oil required by the fluid equipment increases and the drive shaft 1 (rotor 2) is rotated at a high rotational speed to increase the discharge flow rate of the vane pump 100, there is a risk that a shortage of hydraulic oil will be drawn into the second suction port 52. If the amount of hydraulic oil drawn into the second suction port 52 is insufficient, problems such as cavitation may occur.

[0035] Therefore, in the vane pump 100 of this embodiment, the hydraulic oil discharged from the relief valve 90 is guided to the second suction port 52 from a location other than the second connecting passage 17, specifically, through the return passage 14 and the return passage 18, from the side opposite the second connecting passage 17. As a result, the hydraulic oil is supplied to the second suction port 52 not only from the second connecting passage 17 but also from the return passage 18. In other words, in the vane pump 100 of this embodiment, by providing the return passage 14 and the return passage 18, it is possible to increase the flow path area for supplying hydraulic oil to the second suction port 52, which is prone to be disadvantageous in suction at high rotation speeds, and therefore it is possible to prevent a shortage of hydraulic oil being sucked from the second suction port 52.

[0036] In addition, the hydraulic oil discharged from the relief valve 90 is also guided to the first suction port 51 from the side opposite to the first connecting passage 16 through the return passage 14 and the return passage 18. As a result, when there is a shortage of hydraulic oil sucked from the first suction port 51 through the first connecting passage 16, in other words, when the pressure of the first suction port 51 becomes lower than the pressure of the second suction port 52, the hydraulic oil discharged from the relief valve 90 is guided to the first suction port 51. Therefore, it is possible to prevent a shortage of hydraulic oil being sucked from the first suction port 51.

[0037] It is preferable that the connection portion of the return passage 18 with the return passage 14 be closer to the second suction port 52, or in other words, that the length from the opening of the return passage 14 in the return passage 18 to the second suction port 52 be shorter than the length from the opening of the return passage 14 in the return passage 18 to the first suction port 51. This reduces the flow resistance from the return passage 14 to the second suction port 52, thereby further improving the suction efficiency of the hydraulic oil from the return passage 14 through the second suction port 52.

[0038] Furthermore, it is preferable that the connecting portion of the return passage 18 with the return passage 14 be inclined toward the second suction port 52. This configuration allows the hydraulic oil to flow smoothly from the return passage 14 toward the second suction port 52, thereby improving the efficiency of suction of the hydraulic oil from the return passage 14 through the second suction port 52.

[0039] In the above embodiment, the return passage 18 is provided on the outer peripheral surface of the cover-side side plate 30, but this is not limiting. The return passage 18 may be provided between the outer peripheral surface of the body-side side plate 40 and the inner peripheral surface of the installation recess 10a. Furthermore, the return passage 18 may be provided on both the cover-side side plate 30 side and the body-side side plate 40 side. The return passage 18 may also be provided across the outer peripheral surfaces of the cover-side side plate 30 and the cam ring 4.

[0040] Also, for example, the return passage 14 may be directly connected to the second suction port 52 without providing the return passage 18 .

[0041] In the above embodiment, the surplus fluid from the relief valve 90 in the first discharge passage 12 is guided to the second suction port 52. However, a flow control valve may be provided instead of the relief valve 90, and the surplus fluid discharged from the flow control valve may be guided to the second suction port 52. Alternatively, the relief valve 90 may not be provided, and the surplus fluid may be guided to the second suction port 52 through a bypass path that serves as an adjustment mechanism connected to the first discharge passage 12.

[0042] In the above embodiment, the second suction port 52 is disadvantageous in terms of suction in relation to the rotational direction of the rotor 2. However, this is not limited to this. Depending on the flow path length and flow path shape of the first connecting passage 16 and the second connecting passage 17, the degree of suction disadvantage may be determined by the magnitude of flow path resistance, regardless of the rotational direction. For this reason, it is preferable to identify in advance, through experiments or the like, the suction ports that are disadvantageous in terms of suction, and to direct excess fluid from the relief valve 90 to the suction ports that are disadvantageous in terms of suction.

[0043] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0044] The vane pump 100 includes a rotor 2 that is driven to rotate, a plurality of vanes 3 that are provided so as to be capable of reciprocating radially relative to the rotor 2, a cam ring 4 that has an inner peripheral cam surface 4a on which the tip ends of the vanes 3 slide as the rotor 2 rotates, a body 10 that has an accommodating recess 10a that accommodates the rotor 2 and the cam ring 4, a pump chamber 6 that is partitioned by the rotor 2, the cam ring 4, and adjacent vanes 3, a suction passage 11 that introduces working fluid from the outside into the body 10, a first suction port 51 that introduces working oil from the suction passage 11 to the pump chamber 6, a first connecting passage 16 that connects the suction passage 11 and the first suction port 51, a first discharge passage 12 that discharges working oil that has been sucked into the pump chamber 6 from the first suction port 51, and a second suction port 52 that introduces working fluid from the suction passage 11 to the pump chamber 6. a second connecting passage 17 connecting the suction passage 11 and the second suction port 52; a second discharge passage 13 discharging the hydraulic oil sucked into the pump chamber 6 from the second suction port 52 from the pump chamber 6; an adjustment mechanism (a relief valve 90, a flow control valve) adjusting the pressure or flow rate of the hydraulic oil discharged from the pump chamber 6 to the first discharge passage 12; and return passages (a return passage 14, a return passage 18) to which excess fluid discharged from the adjustment mechanism (a relief valve 90, a flow control valve) is guided. The first connecting passage 16 and the second connecting passage 17 branch off from the suction passage 11 in opposite directions across the rotation axis of the rotor 2, and the return passage 18 guides the excess fluid discharged from the adjustment mechanism (a relief valve 90, a flow control valve) to the second suction port 52 from a location different from that of the second connecting passage 17.

[0045] In this configuration, excess fluid guided through the return passages (return passages 14 and 18) is guided to the second suction port 52 from a location other than the second connecting passage 17. This allows the working fluid to be supplied to the second suction port 52 from a flow path other than the second connecting passage 17. Therefore, even when driven at a high rotational speed, it is possible to prevent the second suction port 52 from suctioning an insufficient amount of working fluid.

[0046] The vane pump 100 further includes a side member (cover-side side plate 30) arranged to slide against the rotor 2 and the cam ring 4, and the return passage 18 is formed between the inner peripheral surface of the accommodating recess 10a of the body 10 and the outer peripheral surface of the side member (cover-side side plate 30), and has a first return passage (return passage 18) having one end connected to the first suction port 51 and the other end connected to the second suction port 52, and a second return passage (return passage 14) formed in the body 10 and connecting the first return passage (return passage 18) to an adjustment mechanism (relief valve 90, flow rate adjustment valve).

[0047] With this configuration, it is easier to form a flow path than when the first return passage (return passage 18) is provided in a cover or the like, and the space between the inner surface of the accommodating recess 10a of the body 10 and the outer surface of the side member (cover-side side plate 30), which would otherwise be dead space, can be effectively utilized.

[0048] In the vane pump 100 , the length from the second return passage (return passage 14 ) to the second suction port 52 is shorter than the length from the second return passage (return passage 14 ) to the first suction port 51 .

[0049] With this configuration, the flow resistance from the second return passage (return passage 14) to the second suction port 52 can be reduced, thereby improving the suction efficiency of hydraulic oil from the second return passage (return passage 14) through the second suction port 52.

[0050] In the vane pump 100 , the connection portion of the second return passage (return passage 14 ) with the first return passage (return passage 18 ) is inclined toward the second suction port 52 .

[0051] With this configuration, the flow resistance from the second return passage (return passage 14) to the second suction port 52 can be reduced, thereby improving the suction efficiency of hydraulic oil from the second return passage (return passage 14) through the second suction port 52.

[0052] In the first connecting passage 16 , the working fluid flows in the direction of rotation of the rotor 2 , and in the second connecting passage 17 , the working fluid flows in the direction opposite to the direction of rotation of the rotor 2 .

[0053] In this configuration, the working fluid sucked into the second suction port 52 from the second connecting passage 17 is sucked back in the rotational direction of the rotor 2 from the second connecting passage 17, resulting in high suction resistance. However, since excess fluid discharged from the adjustment mechanism (relief valve 90, flow control valve) is guided to the second suction port 52 from a location other than the second connecting passage 17, it is possible to prevent the amount of working fluid sucked into the second suction port 52 from becoming insufficient.

[0054] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0055] The cover side plate 30 and the body side plate 40 do not necessarily have to be provided if they are not required.

[0056] This application claims priority based on Japanese Patent Application No. 2023-130490, filed with the Japan Patent Office on August 9, 2023, the entire contents of which are incorporated herein by reference.

Claims

a cam ring having an inner peripheral cam surface against which the tip of the vane slides as the rotor rotates; a body having a recess for accommodating the rotor and the cam ring; a pump chamber defined by the rotor, the cam ring, and adjacent vanes; a suction passage for directing working fluid from the outside to the inside of the body; a first suction port for directing working fluid from the suction passage to the pump chamber; a first connecting passage connecting the suction passage and the first suction port; a first discharge passage for discharging working fluid sucked into the pump chamber from the first suction port; a second suction port for directing working fluid from the suction passage to the pump chamber; a second connecting passage connecting the suction passage and the second suction port; and a second discharge passage for discharging working fluid sucked into the pump chamber from the second suction port, from the pump chamber. a vane pump comprising: an adjustment mechanism that adjusts the pressure or flow rate of working fluid discharged from the pump chamber to the first discharge passage; and a return passage through which excess fluid discharged from the adjustment mechanism is guided, wherein the first connection passage and the second connection passage branch off from the suction passage so as to head in opposite directions to each other across the rotational axis of the rotor, and the return passage guides the excess fluid discharged from the adjustment mechanism to the second suction port from a location different from the second connection passage.

2. A vane pump as described in claim 1, further comprising a side member arranged to slide against the rotor and the cam ring, wherein the return passage comprises: a first return passage formed between the inner peripheral surface of the accommodating recess of the body and the outer peripheral surface of the side member, one end of which is connected to the first suction port and the other end of which is connected to the second suction port; and a second return passage formed in the body, which connects the first return passage with the adjustment mechanism.

3. A vane pump according to claim 2, wherein the length from said second return passage to said second suction port is shorter than the length from said second return passage to said first suction port.

4. A vane pump according to claim 2, wherein a connecting portion of said second return passage with said first return passage is inclined toward said second suction port.

5. A vane pump as claimed in claim 3, wherein in said first connecting passage, the working fluid flows in the direction of rotation of said rotor, and in said second connecting passage, the working fluid flows in the opposite direction to the direction of rotation of said rotor.

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