JP7718971B2 - vane pump - Google Patents

Description

The present invention relates to a vane pump in which, when the rotor is driven to rotate, multiple vanes that are slidably mounted in the radial direction of the rotor slide against a cam surface, drawing in fluid through an intake port and discharging it from a discharge port.

In this type of vane pump, vanes are inserted radially into multiple vane-storing slit grooves formed in the rotor, allowing them to slide freely. As the rotor rotates, the tips of the vanes slide against the cam surface. Fluid is drawn into the pump chamber defined by the rotor, vanes, and cam surface through a suction port opening to the suction area, and the fluid drawn into the pump chamber is discharged through a discharge port opening to the discharge area. A side plate is provided against which the rotor's side slides. The side plate's surface is recessed to form an arc-shaped groove on the suction side that is located in the suction area and communicates with the suction side, and an arc-shaped groove on the discharge side that is located in the discharge area and communicates with the discharge side. When the rotor rotates, suction pressure is introduced through the arc-shaped groove on the suction side when the base end of the vane-storing slit groove is positioned in the suction area. And when the base end of the vane-storing slit groove is positioned in the discharge area, discharge pressure is introduced through the arc-shaped groove on the discharge side, pressing the vanes against the cam surface and preventing a loss of sealing performance in the pump chamber.

Japanese Patent Application Laid-Open No. 2021-32218

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 penetrates the side plate. This communication hole connects 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, making it difficult to manufacture inexpensively.

The objective of this invention is to provide a vane pump that can be manufactured inexpensively and easily connects the discharge port to the arc-shaped groove on the discharge side.

In order to achieve this object, the present invention takes the following measures:
a rotor rotatably provided within a pump body; vanes formed on the rotor and inserted radially so as to be slidable; a plurality of slit grooves for accommodating the vanes opened on the outer peripheral 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 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; The vane pump is characterized in that it is provided with a discharge-side arc-shaped groove portion that is connected to the base end of the slit groove and is recessed in the surface of the side plate to introduce some of the discharge fluid, and a communicating groove that connects the discharge-side arc-shaped groove portion to the discharge port is recessed in the surface of the side plate, the communicating groove being wider than 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 being set in a rotational phase state of the rotor where the radially inner end of the central axis of the communicating groove is approximately aligned with the central axis of the vane-storing slit groove .

In this case, the side plates comprise a first side plate that makes sliding contact with one side surface of the rotor at one axial end, and a second side plate that makes sliding contact with the other side surface of the rotor that faces the one side surface in the axial direction. The communication grooves comprise a first communication groove recessed in the first side plate and a second communication groove recessed in the second side plate. The first and second communication grooves may have substantially the same shape and be formed at axially symmetrical positions across the rotor.

As described above, in the invention described in claim 1, a communicating groove that communicates the discharge-side arc-shaped groove and the discharge port is recessed into the surface of the side plate. Because the communicating groove is formed on the surface of the side plate, it is easy to form and can be manufactured more inexpensively than conventional pumps in which communicating holes are formed through the side plate. Furthermore, the communicating groove is wider than the vane-storing slit groove and is inclined relative to the vane-storing slit groove in either the direction of rotor rotation or the counter-rotational direction , with the inclination angle set when the rotor is rotated such that the radially inward end of the central axis of the communicating groove is substantially aligned with the central axis of the vane-storing slit groove. This allows a large flow rate to pass through the communicating groove, smoothly introducing a portion of the discharge fluid into the discharge-side arc-shaped groove, and prevents a vane inserted in the vane-storing slit groove from falling out of the vane-storing slit groove and falling into the communicating groove when the vane passes through the communicating groove due to rotor rotation.

In the invention described in claim 2, the side plates comprise a first side plate that makes sliding contact with one side surface at one axial end of the rotor, and a second side plate that makes sliding contact with the other side surface of the rotor that faces the one side surface in the axial direction. The communication grooves comprise a first communication groove recessed in the first side plate and a second communication groove recessed in the second side plate. The first and second communication grooves have approximately the same shape and are formed in symmetrical positions in the axial direction across the rotor. This allows a portion of the discharge fluid to be introduced approximately evenly into the vane-storing slit groove from both axial sides, enabling good pressure to be applied to the vanes.

1 is a vertical cross-sectional view of a variable displacement vane pump according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG. 1. FIG. 2 is an enlarged cross-sectional view taken along line BB in FIG. 1. FIG. 2 is an enlarged cross-sectional view taken along line CC in FIG. 1. FIG. 3 is an enlarged cross-sectional view corresponding to FIG. 2 showing another embodiment. FIG. 5 is an enlarged cross-sectional view of another embodiment, corresponding to FIG. 3.

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 having a cylindrical bore 2 and a mounting bore 3 connected to the cylindrical bore 2 and extending perpendicular to the bore 2, and a cover 5 closing the cylindrical bore 2. A circular second side plate 6 is mounted in the cylindrical bore 2 and abuts the bottom of the cylindrical bore 2, preventing it from rotating. A circular first side plate 7 is mounted axially away from the second side plate 6 and preventing it from rotating in the cylindrical bore 2. Each side plate 6, 7 is made of a sintered metal material formed 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 mounted rotatably in the cylindrical bore 2 and is disposed between the first side plate 7 and the second side plate 6. One side surface at one axial end of the rotor 8 is in sliding contact with the first side plate 7, and the other side surface axially opposite the first side surface 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 outward and connected to an electric motor (not shown). Reference numeral 9 denotes vane-storing slit grooves drilled radially into the rotor 8, opening on the outer circumferential surface of the rotor 8 and equidistantly spaced around the rotor 8. Each vane-storing slit groove 9 has a base end 10 radially inward, which is circular. Reference numeral 11 denotes a vane, which is inserted radially into the vane-storing slit groove 9 and is slidable radially. Reference numeral 12 denotes a movable ring disposed around the outer periphery of the rotor 8. The movable ring 12 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 forms 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.

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. 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 portion 17A and a second intake port portion 17B. As shown in Figures 2 and 3, the first intake port portion 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 is connected to the intake passage 15 via communication holes 17C and 17D that open on the bottom surface, 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 intake port portion 17B has substantially the same shape as the first intake port portion 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, axially symmetrically to the first intake port portion 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. It consists 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 radially opposite the first suction port portion 17A and is recessed in a semicircular arc into the surface of the first side plate 7 against which one side of the rotor 8 slides. It 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 recessed in a semicircular arc into 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 across the rotor 8.

The pump chamber 14 changes in volume as the rotor 8 rotates in the direction of arrow B, transporting fluid drawn in through the suction port 17 and discharging it through the discharge port 18. The discharge pressure generated within the pump chamber 14 acts on the cam surface 13 of the movable ring 12, moving the movable ring 12 in a direction that reduces the eccentricity with the rotor 8 (to the right in Figure 2). Reference numeral 19 denotes a spring housed in the housing hole 3, which abuts against the outer surface of the movable ring 12 via a holder 20 attached to one end, urging the movable ring 12 in a direction that increases the eccentricity (to the left in Figure 2). Reference numeral 21 denotes a guide screw member threadedly engaged with the housing 4, which abuts against the outer surface of the movable ring 12 approximately perpendicular to the abutment point of the holder 20. This receives the upward component 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 left and right in Figure 2. The guide screw member 21 is provided so that it can be rotated to freely move forward and backward, allowing the vertical position of the movable ring 12 (see Figure 2) to be freely adjusted. 22 is 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 when it abuts against the housing 4. 23 is a discharge rate adjustment member threaded onto the housing 4, which abuts against the outer surface of the movable ring 12 at a position opposite the holder 20 and sets the maximum discharge rate by restricting the maximum eccentricity of the movable ring 12.

1 to 4, reference numeral 24 denotes an inlet-side arc-shaped groove portion that communicates with the base end 10 of the vane-storing slit groove 9 located in the inlet region to introduce suction pressure, and 25 denotes a discharge-side arc-shaped groove portion that communicates with the base end 10 of the vane-storing slit groove 9 located in the discharge region to introduce discharge pressure. The inlet-side arc-shaped groove portion 24 is composed of a first inlet-side arc-shaped groove portion 24A provided in the first side plate 7 and a second inlet-side arc-shaped groove portion 24B provided in the second side plate 6. The first inlet-side arc-shaped groove portion 24A is located radially inward from the first inlet port portion 17A and at approximately the same radial position as the base end 10 of the 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. The first suction side arcuate groove 24A is connected to the suction flow path 15 via communication holes 24C and 24D that open on the bottom surface, penetrate the first side plate 7, and open on the back surface of the first side plate 7. The second suction side arcuate groove 24B has approximately the same shape as the first suction side arcuate groove 24A, and is recessed into the second side plate 6 at a position axially symmetrical to the first suction side arcuate groove 24A across the rotor 8.

The discharge-side arc-shaped groove 25 is composed of a first discharge-side arc-shaped groove 25A provided in the first side plate 7 and a second discharge-side arc-shaped groove 25B provided in the second side plate 6. The first discharge-side arc-shaped groove 25A is concentric with the first suction-side arc-shaped groove 24A and is located at approximately the same radial position as the base end 10 of the vane-accommodating slit groove 9. It is recessed in a semicircular arc and has a circumferential length approximately equal to seven pump chambers 14. The first discharge-side arc-shaped groove 25A communicates with the first discharge port 18A via three first communication grooves 26A, 26B, and 26C recessed in the first side plate 7, and introduces a portion of the discharged fluid. As shown in Figures 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 greater than the groove width W of the vane storage 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 rotational direction B of the rotor 8 relative to the vane storage slit groove 9. The inclination angle α is set to 50 to 70 degrees when the rotor 8 is in a rotational phase state in which the central axis L of the vane storage slit groove 9 is approximately aligned with the radially inner end C of the central axis L1 of the first communication grooves 26A to 26C.

The second discharge side arc-shaped groove 25B has approximately the same shape as the first discharge side arc-shaped groove 25A and is recessed into the second side plate 6 at a position axially symmetrical to the first discharge side arc-shaped groove 25A across the rotor 8. The second discharge side arc-shaped groove 25B is connected to the second discharge port 18B via three second communication grooves 27A, 27B, and 27C recessed into the second side plate 6, and introduces a portion of the discharge fluid. As shown in FIG. 4, each of the second communication grooves 27A, 27B, and 27C has approximately the same shape as the first communication grooves 26A, 26B, and 26C, and is recessed into the second side plate 6 at a position axially symmetrical to the rotor 8 across the rotor 8, with a groove width W1 and an inclination angle α in the rotational direction B of the rotor 8 relative to the vane storage slit groove 9.

Next, the operation of this configuration will be explained.
In the state shown in Figure 2, the movable ring 12 is at its maximum eccentricity position, and when 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. When the movable ring 12 becomes approximately concentric with the rotor 8, the discharge rate becomes zero. When the discharge pressure drops 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.

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

For this operation, communication grooves 26A-26C and 27A-27C are recessed into the surfaces of the side plates 6 and 7, connecting the discharge-side arc-shaped groove portion 25 and the discharge port 18. Because the communication grooves 26A-26C and 27A-27C are formed on the surfaces of the side plates 6 and 7, they are easy to form and can be manufactured more inexpensively than conventional pumps in which communication holes are formed through the side plates. Furthermore, the groove width W1 of the communication grooves 26A-26C and 27A-27C is made larger than the groove width W of the vane-storing slit groove 9, and they are inclined by an inclination angle α in the direction of rotor rotation B relative to the vane-storing slit groove 9. As a result, the communicating grooves 26A-26C and 27A-27C can handle large flow rates, 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 26A-26C and 27A-27C 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 26A-26C and 27A-27C.

The side plates 6, 7 consist of a first side plate 7 that slides against one side surface of one axial end of the rotor 8, and a second side plate 6 that slides against the other side surface of the rotor 8 that faces the one side surface in the axial direction. The communication grooves 26A-26C and 27A-27C consist of first communication grooves 26A-26C recessed into the first side plate 7 and second communication grooves 27A-27C recessed into the second side plate 6. The first communication grooves 26A-26C and second communication grooves 27A-27C have substantially the same shape and are positioned symmetrically in the axial direction across the rotor 8. This allows a portion of the discharge fluid to be introduced substantially evenly into the vane-storing slit groove 9 from both axial sides, effectively pressing the vane 11.

5 and 6 show another embodiment of the present invention, in which 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.

In operation, the rotor 8 is rotated to suck in and discharge fluid, as in the first embodiment.
With this operation, the communicating grooves 28A-28C are formed on the surface of the side plate 7, making them easy to form and, similar to the first embodiment, inexpensive to manufacture. 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 smoothly introducing a portion of the discharge fluid 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 axially symmetrically 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.

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, relative to the vane storage slit groove 9. As a result, a portion 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.

In the above embodiment, three communicating grooves 26A-26C, 27A-27C, and 28A-28C were provided, but the number may be one, two, or four or more. Furthermore, the suction port 17, discharge port 18, suction-side arc-shaped groove 24, discharge-side arc-shaped groove 25, and communicating grooves 26A-26C, 27A-27C, and 28A-28C were provided on both the first side plate 7 and the second side plate 6, but they may also be provided on the first side plate 7 only. Furthermore, while the pump is a variable displacement pump in which the discharge rate becomes approximately zero when the discharge pressure reaches the full cutoff pressure, it is of course also possible to use a fixed displacement pump in which the discharge rate remains approximately constant.

1: Pump body 6: Second side plate (side plate)
7: First side plate (side plate)
8: Rotor 9: Slit groove for accommodating vane 11: Vane 13: Cam surface 14: Pump chamber 17: Suction port 18: Discharge port 25: Discharge-side arc-shaped groove portion 26A, 26B, 26C, 28A, 28B, 28C: First communication groove (communication groove)
27A, 27B, 27C: Second communication groove (communication groove)

Claims (2)

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 . The vane pump described in claim 1, characterized in that the side plates comprise a first side plate that slides against one side surface of the rotor at one axial end, 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, the communication grooves comprising a first communication groove recessed in the first side plate and a second communication groove recessed in the second side plate, the first communication groove and the second communication groove having substantially the same shape and formed at axially symmetrical positions across the rotor.