vane pump

Abstract

To provide a vane pump in which a discharge port and an arcuate groove portion on the discharge side can be easily brought into communication with each other and which can be manufactured inexpensively.SOLUTION: A surface of a side plate 7 is recessed with communication grooves 26A, 26B, 26C for providing communication between a discharge side arcuate groove portion 25 and a discharge port 18. The communication grooves 26A to 26C are formed to have a groove width larger than the groove width W of vane accommodation slit grooves 9. Further, the communication grooves 26A to 26C are formed such that radially-outer ends connected to the discharge port 18 are inclined in the rotation direction B of a rotor 8 with respect to the vane accommodation slit grooves 9.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vane pump in which a plurality of vanes provided slidably in the radial direction of the rotor are brought into sliding contact with a cam surface when the rotor is rotated, and fluid is drawn in through a suction port and discharged from a discharge port. [Background technology]

[0002] In this type of vane pump, vanes are inserted radially into a plurality of vane-accommodating slit grooves formed in a rotor, and as the rotor rotates, the tips of the vanes slide against a cam surface. A pump chamber is defined by the rotor, the vanes, and the cam surface. Fluid is drawn into the pump chamber through a suction port opening to a suction region, and the fluid drawn into the pump chamber is discharged through a discharge port opening to a discharge region. A side plate is provided with a surface against which the rotor slides. The side plate has a recessed surface formed with an arc-shaped suction-side groove located in the suction region and communicating with the suction side, and an arc-shaped discharge-side groove located in the discharge region and communicating with the discharge side. When the rotor rotates, the base ends of the vane-accommodating slit grooves are positioned in the suction region, allowing suction pressure to be introduced through the arc-shaped suction-side groove. When the base ends of the vane-accommodating slit grooves are positioned in the discharge region, discharge pressure is introduced through the arc-shaped discharge-side groove, pressing the vanes against the cam surface and preventing a deterioration in the sealing performance of the pump chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-32218 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such conventional vane pumps, the arc-shaped groove on the discharge side, which is formed as a recess in the surface of the side plate, communicates with the discharge flow path via a communication hole that passes through the side plate, and this communication hole is formed by connecting a small-diameter hole that opens into the bottom surface of the arc-shaped groove with a large-diameter hole that opens into the back surface of the side plate, and because a wall surface is formed at this connection, forming the communication hole is complicated, which creates the problem of not being able to manufacture the pump inexpensively.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a vane pump which can be manufactured inexpensively and in which the discharge port and the arc-shaped groove on the discharge side can be easily connected to each other. [Means for solving the problem]

[0006] In order to achieve this object, the present invention takes the following measures: The pump comprises a rotor rotatably mounted within a pump body, vanes formed on the rotor and inserted radially so as to slide freely, a plurality of slit grooves for accommodating the vanes opening on the outer circumferential surface of the rotor, a cam surface surrounding the outer periphery of the rotor and against which the tips of the vanes slide, a side plate against which the side of the rotor slides, a pump chamber defined by the rotor, vanes, cam surface and side plate, the volume of which changes with the rotation of the rotor and which draws in and discharges fluid, a suction port opening into a suction area whose volume expands in response to the rotation of the rotor, and a pump chamber opening into a suction area whose volume expands in response to the rotation of the rotor. The pump includes a discharge port that opens into a discharge region where the volume of the pump chamber is reduced accordingly, and a discharge-side arc-shaped groove portion that is recessed into the surface of the side plate and communicates with the base end of the vane-storing slit groove located in the discharge region, and introduces a portion of the discharge fluid. A communication groove that communicates the discharge-side arc-shaped groove portion and the discharge port is recessed into the surface of the side plate, and the communication groove is formed to have a groove width larger than that of the vane-storing slit groove, and is formed at an angle relative to the vane-storing slit groove in the rotational direction of the rotor or in the counter-rotational direction opposite to the rotational direction. The angle of inclination is set in a rotor rotation phase state in which the central axis of the vane-accommodating slit groove is approximately aligned with the radially inner end of the central axis of the communication groove. This is a vane pump that is characterized by the above.

[0007] In this case, the side plate comprises a first side plate that slides against one side surface of the rotor at one axial end thereof, and a second side plate that slides against the other side surface of the rotor that faces the one side surface in the axial direction, and the communicating groove comprises a first communicating groove recessed in the first side plate and a second communicating groove recessed in the second side plate, and the first communicating groove and the second communicating groove may have approximately the same shape and be formed at symmetrical positions in the axial direction across the rotor. [Effects of the Invention]

[0008] As described above in detail, in the invention described in claim 1, a communication groove that connects the discharge side arcuate groove portion and the discharge port is recessed into the surface of the side plate. Therefore, since the communication groove is formed on the surface of the side plate, it is easy to form and can be manufactured at low cost compared to conventional pumps in which communication holes are formed through the side plate. In addition, the communication groove is formed to have a larger groove width than the vane storage slit groove, and is formed to be inclined in the direction of rotation of the rotor or in the counter-rotational direction opposite to the rotational direction relative to the vane storage slit groove. The angle of inclination is set in a rotor rotation phase state in which the central axis of the vane-accommodating slit groove is approximately aligned with the radially inner end of the central axis of the communication groove. As a result, the communicating groove can allow a large flow rate to pass through, allowing a portion of the discharge fluid to be smoothly introduced into the discharge-side arc-shaped groove portion, and also preventing the vanes inserted into the vane-storing slit grooves from falling out of the vane-storing slit grooves and dropping into the communicating groove when the vanes pass through the communicating groove due to the rotation of the rotor.

[0009] In the invention described in claim 2, the side plates comprise a first side plate in sliding contact with one side surface at one axial end of the rotor, and a second side plate in sliding contact with the other side surface axially opposite to the one side surface of the rotor, and the communicating grooves comprise a first communicating groove recessed in the first side plate and a second communicating groove recessed in the second side plate, the first communicating groove and the second communicating groove having substantially the same shape and being formed at symmetrical positions in the axial direction across the rotor. This allows a portion of the discharge fluid to be introduced substantially evenly into the vane-accommodating slit groove from both sides in the axial direction, thereby effectively pressing the vane. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a vertical cross-sectional view of a variable displacement vane pump according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is an enlarged cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 2 is an enlarged cross-sectional view taken along line CC in FIG. [Figure 5] FIG. 10 is an enlarged cross-sectional view corresponding to FIG. 2 showing another embodiment. [Figure 6] FIG. 4 is an enlarged cross-sectional view of another embodiment, corresponding to FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention as a variable displacement vane pump will be described with reference to the drawings. In Figures 1 and 2, the pump body 1 is composed of a housing 4 with a cylindrical bore 2 and a mounting bore 3 connected to the bore 2 and extending perpendicular to the bore 2, and a cover 5 that closes the bore 2. A circular second side plate 6 is fitted into the bore 2 and abuts the bottom of the bore 2, preventing it from rotating. A circular first side plate 7 is fitted axially away from the second side plate 6 and is fixedly fitted to the bore 2, preventing it from rotating. Each side plate 6 and 7 is made of a sintered metal material made by molding and sintering metal powder, and corresponds to the sintered material for machine structural parts specified in Japanese Industrial Standard JIS Z2550:2016. A rotor 8 is fitted rotatably into the bore 2 and is positioned between the first side plate 7 and the second side plate 6. One side surface at one axial end of the rotor is in sliding contact with the first side plate 7, and the other side surface facing the first side is in sliding contact with the second side plate 6. The rotor 8 has a first shaft 8A protruding from one side and a second shaft 8B protruding from the other side. The first shaft 8A is journaled on the cover 5. The second shaft 8B is journaled on the housing 4, with its tip protruding to the outside and connected to an electric motor (not shown). 9 denotes vane-storing slit grooves drilled radially into the rotor 8. They open onto the outer periphery of the rotor 8 and are spaced at equal intervals around the circumference of the rotor 8, with thirteen of them. Each vane-storing slit groove 9 has a base end 10 on the radially inward side, which is circular. 11 denotes a vane, which is inserted radially into the vane-storing slit groove 9 and is slidable radially. 12 denotes a movable ring disposed around the outer periphery of the rotor 8. It is disposed between the first side plate 7 and the second side plate 6 of the cylindrical hole 2 and is eccentrically movable left and right relative to the rotor 8 in FIG. 2 . The inner peripheral surface of the movable ring 12 serves as a cam surface 13, which is in sliding contact with the tip of the vane 11. Reference numeral 14 denotes a pump chamber, which is defined by both side plates 6 and 7, the rotor 8, the vane 11, and the cam surface 13 of the movable ring 12, and its volume changes as the rotor 8 rotates in the direction of arrow B.

[0012] Reference numeral 15 denotes an intake passage for drawing in fluid, and 16 denotes a discharge passage for discharging fluid, both of which are drilled through the cover 5. Reference numeral 17 denotes an intake port that opens into the intake region where the volume of the pump chamber 14 expands, and is composed of a first intake port 17A and a second intake port 17B. As shown in FIGS. 2 and 3, the first intake port 17A is formed as a semicircular recess in the surface of the first side plate 7 against which one side of the rotor 8 slides, and communicates with the intake passage 15 through communication holes 17C and 17D that open on the bottom, penetrate the first side plate 7, and open on the back surface of the first side plate 7. As shown in FIG. 4, the second intake port 17B has substantially the same shape as the first intake port 17A and is formed as a semicircular recess in the surface of the second side plate 6 against which the other side of the rotor 8 slides, at a position axially symmetrical to the first intake port 17A and the rotor 8. Reference numeral 18 denotes a discharge port that opens into the discharge region where the volume of the pump chamber 14 is reduced, and is composed of a first discharge port portion 18A and a second discharge port portion 18B. As shown in Figures 2 and 3, the first discharge port portion 18A is formed as a semicircular recess in the surface of the first side plate 7, against which one side of the rotor 8 slides, at a position radially opposite the center of the first suction port portion 17A, and communicates with the discharge flow path 16 through communication holes 18C, 18D, and 18E that open at the bottom, penetrate the first side plate 7, and open on the back surface of the first side plate 7. As shown in Figure 4, the second discharge port portion 18B has substantially the same shape as the first discharge port portion 18A, and is formed as a semicircular recess in the surface of the second side plate 6, against which the other side of the rotor 8 slides, at a position axially symmetrical to the first discharge port portion 18A and the rotor 8.

[0013] The volume of the pump chamber 14 changes as the rotor 8 rotates in the direction of arrow B, transporting the fluid drawn in through the suction port 17 and discharging it from the discharge port 18. The force of the discharge pressure generated inside the pump chamber 14 acts on the cam surface 13 of the movable ring 12, moving the movable ring 12 in a direction to decrease the eccentricity with the rotor 8 (to the right in FIG. 2). 19 denotes a spring housed in the housing hole 3, which abuts against the outer circumferential surface of the movable ring 12 via a holder 20 attached to one end, and urges the movable ring 12 in a direction to increase the eccentricity (to the left in FIG. 2). 21 denotes a guide screw member threadedly engaged with the housing 4, which abuts against the outer circumferential surface of the movable ring 12 at a position approximately perpendicular to the abutment point of the holder 20. The guide screw member 21 receives the upward component of the force of the discharge pressure acting on the cam surface 13 of the movable ring 12 in accordance with the position of the discharge port 18, guiding the movement of the movable ring 12 in the left-right direction in FIG. 2. The guide screw member 21 is provided so that it can be rotated to move forward and backward freely, allowing the vertical position of the movable ring 12 in Figure 2 to be adjusted freely. Reference numeral 22 denotes a lock nut member threaded onto the guide screw member 21, which is provided so that it can move toward and away from the housing 4 and restricts the rotation of the guide screw member 21 by abutting against the housing 4. Reference numeral 23 denotes a discharge rate adjustment member threaded onto the housing 4, which abuts against the outer peripheral surface of the movable ring 12 at a position opposite the holder 20 and sets the maximum discharge rate by regulating the maximum eccentricity of the movable ring 12.

[0014] 1 to 4, reference numeral 24 denotes a suction-side arcuate groove that communicates with base end 10 of vane-storing slit groove 9 located in the suction region to introduce suction pressure, and 25 denotes a discharge-side arcuate groove that communicates with base end 10 of vane-storing slit groove 9 located in the discharge region to introduce discharge pressure. Suction-side arcuate groove 24 is comprised of a first suction-side arcuate groove 24A provided in first side plate 7 and a second suction-side arcuate groove 24B provided in second side plate 6. First suction-side arcuate groove 24A is located radially inward from first suction port 17A and at approximately the same radial position as base end 10 of vane-storing slit groove 9. It is recessed in a semicircular arc shape and has a circumferential length approximately equal to three pump chambers 14. First suction side arcuate groove 24A is connected to suction flow passage 15 via communication holes 24C and 24D that open to the bottom surface, penetrate first side plate 7, and open to the rear surface of first side plate 7. Second suction side arcuate groove 24B has substantially the same shape as first suction side arcuate groove 24A, and is recessed into second side plate 6 at a position axially symmetrical to first suction side arcuate groove 24A with rotor 8 interposed therebetween.

[0015] Discharge-side arcuate groove 25 is composed of first discharge-side arcuate groove 25A provided in first side plate 7 and second discharge-side arcuate groove 25B provided in second side plate 6. First discharge-side arcuate groove 25A is concentric with first suction-side arcuate groove 24A and is located at approximately the same radial position as base end 10 of vane-accommodating slit groove 9. It is recessed in a semicircular arc and has a circumferential length approximately equal to seven pump chambers 14. First discharge-side arcuate groove 25A communicates with first discharge port 18A via three first communication grooves 26A, 26B, and 26C recessed in first side plate 7, and introduces a portion of the discharged fluid. 2 and 3, the first communication grooves 26A, 26B, and 26C are arranged at equal intervals in the circumferential direction, with a groove width W1 larger than the groove width W of the vane-storing slit groove 9. Furthermore, the radially outer end of each of the first communication grooves 26A, 26B, and 26C, which connects to the first discharge port portion 18A, is inclined at an inclination angle α in the rotation direction B of the rotor 8 with respect to the vane-storing slit groove 9. The inclination angle α is set to 50 to 70 degrees in a rotational phase state of the rotor 8 in which the central axis L of the vane-storing slit groove 9 substantially coincides with the radially inner end C of the central axis L1 of the first communication grooves 26A to 26C.

[0016] The second discharge-side arcuate groove 25B has substantially the same shape as the first discharge-side arcuate groove 25A and is recessed in the second side plate 6 at a position axially symmetrical to the first discharge-side arcuate groove 25A with the rotor 8 positioned therebetween. The second discharge-side arcuate groove 25B communicates with the second discharge port 18B via three second communication grooves 27A, 27B, and 27C recessed in the second side plate 6, and introduces a portion of the discharged fluid. As shown in FIG. 4 , the second communication grooves 27A, 27B, and 27C have substantially the same shape as the first communication grooves 26A, 26B, and 26C, and are recessed in the second side plate 6 at a position axially symmetrical to the rotor 8 with the groove width W1 and inclined at an inclination angle α in the rotation direction B of the rotor 8 with respect to the vane storage slit groove 9.

[0017] Next, the operation of this configuration will be explained. In the state shown in Figure 2, when the movable ring 12 is at the maximum eccentricity position and the rotor 8 is rotated in the direction of arrow B, the fluid drawn into the pump chamber 14 through the suction port 17 is discharged from the discharge port 18, achieving the maximum discharge rate. When the force of the discharge pressure acting on the cam surface 13 of the movable ring 12 in the rightward direction in Figure 2 exceeds the set pressure set by the spring force of the spring 19, the movable ring 12 moves rightward in Figure 2, guided by the guide screw member 21, to reduce the eccentricity, thereby reducing the discharge rate, and the movable ring 12 becomes approximately concentric with the rotor 8, thereby reducing the discharge rate to zero. When the discharge pressure falls below the set pressure due to the reduced discharge rate, the movable ring 12 moves leftward in Figure 2, guided by the guide screw member 21, due to the spring force of the spring 19, thereby increasing the discharge rate.

[0018] As rotor 8 rotates in the direction of arrow B, in the suction region, suction pressure is introduced from suction side arcuate groove portion 24 to base end portion 10 of vane storage slit groove 9, pressing vane 11 against cam surface 13. In the discharge region, part of the fluid discharged from discharge port 18 flows through first communicating grooves 26A-26C (second communicating grooves 27A-27C) and is introduced from discharge side arcuate groove portion 25 to base end portion 10 of vane storage slit groove 9, pressing vane 11 against cam surface 13.

[0019] For this operation, communicating grooves 26A-26C and 27A-27C that connect discharge-side arcuate groove portion 25 and discharge port 18 are recessed into the surfaces of side plates 6 and 7. Because communicating grooves 26A-26C and 27A-27C are formed in the surfaces of side plates 6 and 7, they are easy to form and can be manufactured more inexpensively than conventional pumps in which communicating holes are formed through the side plates. Furthermore, the groove width W1 of communicating grooves 26A-26C and 27A-27C is made larger than the groove width W of vane-storing slit groove 9, and they are inclined at an inclination angle α in the direction of rotor rotation B relative to vane-storing slit groove 9. As a result, the communicating grooves 26A to 26C, 27A to 27C can allow a large flow rate to pass through, allowing a portion of the discharge fluid to be smoothly introduced into the discharge side arc-shaped groove portion 25, and also prevents the vanes 11 inserted into the vane storage slit grooves 9 from falling out of the vane storage slit grooves 9 and into the communicating grooves 26A to 26C, 27A to 27C as the rotor 8 rotates and passes through the communicating grooves 26A to 26C, 27A to 27C.

[0020] The side plates 6, 7 are made up of a first side plate 7 in sliding contact with one side surface of one axial end of the rotor 8, and a second side plate 6 in sliding contact with the other side surface of the rotor 8 that faces the one side surface in the axial direction, and the communicating grooves 26A to 26C and 27A to 27C are made up of first communicating grooves 26A to 26C recessed into the first side plate 7 and second communicating grooves 27A to 27C recessed into the second side plate 6, and the first communicating grooves 26A to 26C and the second communicating grooves 27A to 27C have approximately the same shape and are formed in symmetrical positions in the axial direction across the rotor 8. This allows a portion of the discharge fluid to be introduced approximately evenly into the vane-accommodating slit groove 9 from both sides in the axial direction, thereby effectively pressing the vanes 11.

[0021] 5 and 6 show another embodiment of the present invention, and the same parts as those in the first embodiment are given the same reference numerals and their explanations are omitted, and only the different parts will be explained. The three first communicating grooves 28A, 28B, 28C recessed into the surface of the first side plate 7 have their radially outer ends connected to the first discharge port portion 18A inclined at an inclination angle α in the counter-rotational direction opposite the rotational direction B of the rotor 8 with respect to the vane-storing slit groove 9. The inclination angle α is set to 50 to 70 degrees in a rotational phase state of the rotor 8 in which the central axis L of the vane-storing slit groove 9 substantially coincides with the radially inner end C of the central axis L1 of the first communicating grooves 28A to 28C.

[0022] In operation, the rotor 8 is rotated to suck in and discharge fluid, as in the first embodiment. With this operation, since the communicating grooves 28A-28C are formed on the surface of the side plate 7, they are easy to form and, similar to the first embodiment, can be manufactured inexpensively. Furthermore, the groove width W1 of the communicating grooves 28A-28C is formed larger than the groove width W of the vane-storing slit grooves 9, allowing a large flow rate to pass through and allowing a portion of the discharge fluid to be smoothly introduced into the discharge-side arc-shaped groove portion 25. Furthermore, when the vanes 11 inserted into the vane-storing slit grooves 9 pass through the communicating grooves 28A-28C due to the rotation of the rotor 8, they are prevented from falling out of the vane-storing slit grooves 9 and into the communicating grooves 28A-28C. Furthermore, the second communicating grooves (not shown) recessed in the second side plate 6 have substantially the same shape as the first communicating grooves 28A-28C recessed in the first side plate 7 and are formed symmetrically in the axial direction across the rotor 8. Therefore, a part of the discharge fluid can be introduced into the vane-accommodating slit groove 9 from both sides in the axial direction approximately evenly, and the vane 11 can be pressed well.

[0023] Furthermore, the first communication grooves 28A-28C are formed so that their radially outer ends, which connect to the first discharge port portion 18A, are inclined in the counter-rotational direction opposite the rotational direction B of the rotor 8 with respect to the vane accommodating slit groove 9. As a result, part of the fluid discharged from the first discharge port portion 18A flows through the first communication grooves 28A-28C in the same direction as the rotational direction B of the rotor 8, making it even easier to introduce the fluid into the discharge-side arc-shaped groove portion 25.

[0024] In the above-described embodiment, three communicating grooves 26A-26C, 27A-27C, and 28A-28C are provided, but the number may be one, two, or four or more. Furthermore, while suction port 17, discharge port 18, suction-side arcuate groove 24, discharge-side arcuate groove 25, and communicating grooves 26A-26C, 27A-27C, and 28A-28C are provided in both first side plate 7 and second side plate 6, they may be provided only in first side plate 7. Furthermore, although a variable displacement type is used in which the discharge rate becomes approximately zero when the discharge pressure reaches the full cutoff pressure, a fixed displacement type in which the discharge rate is approximately constant may also be used. [Explanation of symbols]

[0025] 1: Pump body 6:Second side plate (side plate) 7: 1st side plate (side plate) 8: Rotor 9: Slit groove for storing vanes 11: Vane 13: Cam surface 14: Pump room 17: Intake port 18: Discharge port 25: Arc-shaped groove on discharge side 26A, 26B, 26C, 28A, 28B, 28C: 1st communication groove (communication groove) 27A, 27B, 27C: 2nd communication groove (communication groove)

Claims

1. a rotor rotatably mounted within a pump body; vanes formed on the rotor and inserted radially so as to slide freely; a plurality of slit grooves for accommodating the vanes, which are opened on the outer circumferential surface of the rotor; a cam surface surrounding the outer periphery of the rotor and against which the tips of the vanes slide; a side plate against which the side of the rotor slides; a pump chamber defined by the rotor, vanes, cam surface and side plate, whose volume changes with the rotation of the rotor to suck in and discharge fluid; a suction port opening into a suction region where the volume of the pump chamber expands as the rotor rotates; a discharge port opening into a discharge region where the volume of the pump chamber contracts as the rotor rotates; and vanes located in the discharge region. a discharge-side arc-shaped groove portion that communicates with a base end of the storage slit groove and is recessed in the surface of the side plate to introduce a portion of the discharge fluid, and a communicating groove that communicates the discharge-side arc-shaped groove portion and the discharge port is recessed in the surface of the side plate, the communicating groove being wider than the vane storage slit groove and being inclined in the direction of rotation of the rotor or in a counter-rotational direction opposite to the direction of rotation relative to the vane storage slit groove, the inclination angle being set when the rotor is in a rotational phase state in which the central axis of the vane storage slit groove approximately coincides with the radially inner end of the central axis of the communicating groove.

2. 2. The vane pump according to claim 1, wherein the side plates comprise a first side plate in sliding contact with one side surface of the rotor at one axial end thereof, and a second side plate in sliding contact with the other side surface of the rotor that faces the one side surface in the axial direction, the communicating grooves comprising a first communicating groove recessed in the first side plate and a second communicating groove recessed in the second side plate, the first communicating groove and the second communicating groove having substantially the same shape and being formed at axially symmetrical positions across the rotor.

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