Vane pump

Abstract

To provide a vane pump that restrains wear of vanes, and vane housing slit grooves with which the vanes are in sliding contact, and can be easily manufactured.SOLUTION: A vane pump comprises a rotor 4 rotatably provided in a pump body; a plurality of vane housing slit grooves 5 formed in the rotor 4, and of which one end is opened in a rotor outer peripheral surface; and vanes 7 inserted into the vane housing slit grooves 5 so as to be slidable in a radial direction. In each of the vanes 7, a cutout 7C is formed in a corner part K at which a side surface 7A on a front side in a rotation direction C of the rotor 4 intersects with a bottom surface 7B on a central side in a radial direction opposed to a tip. In the cutout 7C, a surface is formed as a crowned convex curved surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vane pump in which a plurality of vanes, which are provided so as to be slidable in the radial direction of the rotor, come into sliding contact with a cam surface when the rotor is rotated, and which draws in fluid through a suction port and discharges it from a discharge port. [Background technology]

[0002] In this type of vane pump, vanes are inserted radially into a plurality of vane-storing slit grooves formed in the rotor so that they can slide freely in the radial direction, and as the rotor rotates, the tips of the vanes slide against the cam surface, drawing fluid into a pump chamber defined by the rotor, vanes, and cam surface through a suction port opening to the suction region, and discharging the fluid drawn into the pump chamber through a discharge port opening to the discharge region. The vanes are provided with reinforcing members at corners on the base end side, forward in the direction of rotor rotation, to prevent wear at the corners of the vanes that slide against the vane-storing slit grooves as the rotor rotates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-48182 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such conventional vane pumps, reinforcing members are provided at the corners of the vanes, which requires the reinforcing members to be prepared separately and attached to the vanes, making the manufacture of the vanes complicated and time-consuming.

[0005] An object of the present invention is to provide a vane pump that can be easily manufactured and that suppresses wear of the vanes and the vane-accommodating slit grooves in which the vanes slide. [Means for solving the problem]

[0006] In order to achieve this object, the present invention takes the following measures: the rotor is rotatably mounted within the pump body; a plurality of slit grooves for accommodating vanes formed in the rotor and having one end opening onto the outer circumferential surface of the rotor; vanes that are inserted radially into the slit grooves for accommodating vanes; a cam surface that surrounds the outer periphery of the rotor and against which the tips of the vanes slide; a pump chamber that is partitioned by the rotor, vanes, and cam surface and whose volume changes with the rotation of the rotor to suck in and discharge fluid; an suction port that opens into the suction area where the volume of the pump chamber expands as the rotor rotates; and a discharge port that opens into the discharge area where the volume of the pump chamber reduces as the rotor rotates, and the vane has a notch formed in the corner where the side surface on the forward side in the direction of rotation of the rotor intersects with the bottom surface on the radial center side opposite the tip, and the notch has a surface that is formed into a convex curved surface with a central peak.

[0007] In this case, the notch may have the surface along a line connecting a first position and a second position, the first position being a position spaced apart from the corner along the bottom surface in a counter-rotational direction opposite to the rotational direction by a distance substantially equal to a gap dimension between the vane and the vane-storing slit groove in the rotational direction, and the second position being a position spaced apart from the corner along the side surface radially outward by a distance that is 30 to 40% of the radial remaining dimension of the vane remaining in the vane-storing slit groove when the vane is in a state where it protrudes to its maximum from the vane-storing slit groove. The curved surface of the notch may also be formed by crowning. [Effects of the Invention]

[0008] As described above in detail, in the invention described in claim 1, the vane has a notch formed in the corner where the side surface on the forward side in the direction of rotation of the rotor intersects with the bottom surface on the radial center side opposite the tip, and the surface of the notch is formed into a convexly curved surface. As a result, it is the surface of the notch in the vane that comes into sliding contact with the vane storage slit groove as the rotor rotates, so the surface pressure of the vane sliding into the vane storage slit groove can be reduced and wear of the vane and the vane storage slit groove can be suppressed. Furthermore, because the surface of the notch in the corner of the vane that comes into sliding contact with the vane storage slit groove is formed into a convexly curved surface, no additional parts are required and the pump can be manufactured more easily than conventional pumps in which additional reinforcing members are attached to the vane corners.

[0009] In the invention described in claim 2, the notch has a surface along a line connecting the first position and the second position, the first position being a position spaced from the corner along the bottom surface in a counter-rotational direction by a distance substantially equal to the gap between the vane and the vane-storing slit groove in the rotational direction, and the second position being a position spaced from the corner along the side surface radially outward by a distance that is 30 to 40% of the radial remaining dimension of the vane remaining in the vane-storing slit groove when the vane is in a state where it has fully protruded from the vane-storing slit groove. Therefore, the surface of the notch between the first and second positions of the vane is in reliable sliding contact with the vane-storing slit groove, so that the surface pressure of the vane in sliding contact with the vane-storing slit groove can be more reliably reduced and wear of the vane and the vane-storing slit groove can be more reliably suppressed.

[0010] In the invention described in claim 3, the surface of the notch is formed into a curved surface by crowning, which allows the surface of the notch to be formed into a convex curved surface with high precision. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a vertical cross-sectional view of a vane pump according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view of a main part A in FIG. [Figure 3]FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2. [Figure 4] FIG. 10 is an enlarged cross-sectional view corresponding to FIG. 2 showing another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention in which the vane pump is a variable displacement vane pump will be described with reference to the drawings. In Figure 1, 1 denotes a pump body having a cylindrical bore 2 and a mounting bore 3 that is connected to the cylindrical bore 2 and perpendicular to the bore 2. 4 denotes a rotor mounted in the cylindrical bore 2. It is rotatably supported by the pump body 1, with its tip protruding outward and connected to an electric motor (not shown). 5 denotes radially drilled vane-mounting slits in the rotor 4, opening onto the outer periphery of the rotor 4. Thirteen vane-mounting slits 5 are evenly spaced around the rotor 4. Each vane-mounting slit 5 has a base end 6 that is radially inward and circular. 7 denotes a vane that is inserted radially into the vane-mounting slit 9. 8 denotes a movable ring 8 that surrounds the outer periphery of the rotor 4 and is positioned in the cylindrical bore 2. It is eccentrically movable left and right relative to the rotor 4 in Figure 1. The inner periphery of the movable ring 8 forms a cam surface 9, against which the tip of the vane 7 slides. Reference numeral 10 denotes a pump chamber, which is defined by the rotor 4, the vanes 7, and the cam surface 9 of the movable ring 8, and the volume thereof changes as the rotor 4 rotates in the rotation direction C.

[0013] 2 and 3, vane 7 has notch 7C formed at corner K where side surface 7A on the forward side in the rotation direction C of rotor 4 intersects with bottom surface 7B on the radial center side opposite the tip. Notch 7C has a surface along a line connecting first position 7D and second position 7E, and this surface is formed into a convex-shaped curved surface by crowning. As rotor 4 rotates, notch 7C's surface formed into a convex-shaped curved surface slides against vane-storing slit groove 5.

[0014] The first position 7D is a position where the vane 7 is spaced from the corner K along the bottom surface 7B in the counter-rotational direction opposite to the rotational direction C by a dimension H2 that is approximately equal to the gap dimension H1 between the vane 7 and the vane storage slit groove 5 in the rotational direction C of the rotor 4. The second position 7E is a position where the vane 7 is spaced from the corner K radially outward along the side surface 7A by a dimension 7G that is 35% of the radial remaining dimension 7F of the vane 7 remaining in the vane storage slit groove 5 when the vane 7 is in a state where it has protruded to the maximum extent from the vane storage slit groove 5.

[0015] It is preferable that dimension 7G be in the range of 30 to 40% of radial remaining dimension 7F. If dimension 7G exceeds 40% of radial remaining dimension 7F, first position 7D of vane 7 may come into sliding contact with vane accommodating slit groove 5, and the surface of notch 7C may not come into sliding contact with vane accommodating slit groove 5. If dimension 7G is less than 30% of radial remaining dimension 7F, second position 7E of vane 7 may come into sliding contact with vane accommodating slit groove 5, and the surface of notch 7C may not come into sliding contact with vane accommodating slit groove 5.

[0016] Reference numeral 11 denotes an intake port that opens into the intake region where the volume of the pump chamber 10 expands, and is formed as a semicircular recess in the side plate (not shown) against which the side surface of the rotor 4 slides. Reference numeral 12 denotes a discharge port that opens into the discharge region where the volume of the pump chamber 10 contracts, and is formed as a semicircular recess in the side plate (not shown) against which the side surface of the rotor 4 slides, at a position radially opposite to the intake port 11 via the center.

[0017] The volume of pump chamber 10 changes as rotor 4 rotates in rotation direction C, transporting the fluid drawn in from suction port 11 and discharging it from discharge port 12. The force of discharge pressure generated inside pump chamber 10 acts on cam surface 9 of movable ring 8, moving movable ring 8 in the direction of decreasing the eccentricity with rotor 4 (to the left in Figure 1). Reference numeral 13 denotes a cover member that closes the opening of mounting hole 3 and is fixed to pump body 1.

[0018] Reference numeral 14 denotes a spring housed in the housing hole 3, with a holder 15 attached to one end and a spring receiving member 16 attached to the other end axially opposite the one end. The spring 14 abuts against the outer surface of the movable ring 8 via the holder 15, urging the movable ring 8 in the direction of increasing eccentricity (to the right in Figure 1). Reference numeral 17 denotes a pressure adjusting member rotatably threadedly engaged with the cover member 13, abutting against the other end of the spring 14 via the spring receiving member 16 and movable back and forth in the axial direction when rotated. The pressure adjusting member 17 extends and contracts the spring 14 when rotated, changing the spring force and allowing the full cutoff pressure to be freely changed. Reference numeral 18 denotes a lock nut member threadedly engaged with the pressure adjusting member 17, which is attached so as to be movable toward and away from the cover member 13 and restricts the rotation of the pressure adjusting member 17 when it abuts against the cover member 13.

[0019] Reference numeral 19 denotes a guide screw member threadedly engaged with pump body 1, which abuts against the outer peripheral surface of movable ring 8 at a position approximately perpendicular to the abutment point of holder 15. It receives the upward force (Fig. 1) of the discharge pressure acting on cam surface 9 of movable ring 8 corresponding to the position of discharge port 12, and is configured to guide movement of movable ring 8 in the left-right direction (Fig. 1). Guide screw member 19 is configured to be freely advanced and retreated by rotation, allowing the vertical position of movable ring 12 to be freely adjusted in Fig. 1. Reference numeral 20 denotes a lock nut member threadedly engaged with guide screw member 19, which is configured to be freely moved toward and away from pump body 1 and abuts against pump body 1 to restrict the rotation of guide screw member 19. Reference numeral 21 denotes a discharge rate adjustment member threadedly engaged with pump body 1, which abuts against the outer peripheral surface of movable ring 8 at a position opposite holder 15 and restricts the maximum eccentricity of movable ring 8 to set the maximum discharge rate. Reference numeral 22 denotes a lock nut member screwed onto the discharge rate adjusting member 21, which is provided so as to be able to move toward and away from the pump body 1 and restricts the rotation of the discharge rate adjusting member 21 when it comes into contact with the pump body 1.

[0020] Reference numeral 23 denotes a suction-side arc-shaped groove that communicates with the base end 6 of the vane-storing slit groove 5 located in the suction region to introduce suction pressure, and 24 denotes a discharge-side arc-shaped groove that communicates with the base end 6 of the vane-storing slit groove 5 located in the discharge region to introduce discharge pressure. The suction-side arc-shaped groove 23 is located radially inward from the suction port 11 and at approximately the same radial position as the base end 6 of the vane-storing slit groove 5, and is formed as a semicircular recess in the side plate (not shown) with which the side surface of the rotor 4 slides, with a circumferential length approximately equal to three pump chambers 10.

[0021] The discharge side arc-shaped groove 24 is concentric with the suction side arc-shaped groove 23 and is located at approximately the same radial position as the base end 6 of the vane storage slit groove 5.It is formed as a semicircular recess in the side plate (not shown) against which the side of the rotor 4 slides, and its circumferential length is approximately equal to seven pump chambers 10.

[0022] Next, the operation of this configuration will be explained. In the state shown in Figure 1, movable ring 8 is at its maximum eccentricity position. When rotor 4 is rotated in rotation direction C, fluid drawn into pump chamber 10 through suction port 11 is discharged from discharge port 12, achieving the maximum discharge rate. When the force of discharge pressure acting leftward in Figure 1 on cam surface 9 of movable ring 8 exceeds the set pressure set by the spring force of spring 14, movable ring 8 moves leftward in Figure 1, guided by guide screw member 19, to reduce the eccentricity, thereby decreasing the discharge rate. When movable ring 8 becomes approximately concentric with rotor 4, the discharge rate becomes zero. When the discharge pressure drops below the set pressure due to the decrease in discharge rate, movable ring 8 moves rightward in Figure 1, guided by guide screw member 19, due to the spring force of spring 14, thereby increasing the discharge rate.

[0023] As rotor 4 rotates in rotation direction C, in the suction region, suction pressure is introduced from suction side arcuate groove 23 to base end 6 of vane storage slit groove 5, pressing vane 7 against cam surface 9. In the discharge region, part of the discharge fluid is introduced from discharge side arcuate groove 24 to base end 6 of vane storage slit groove 5, pressing vane 7 against cam surface 9.

[0024] In this operation, vane 7 has notch 7C formed at corner K where side surface 7A on the forward side in the rotation direction C of rotor 4 intersects with bottom surface 7B on the radial center side opposite the tip, and notch 7C forms a convexly curved surface. Therefore, it is the surface of notch 7C in vane 7, which is a convexly curved surface, that comes into sliding contact with vane storage slit groove 5 as rotor 4 rotates, so that the surface pressure of vane 7 in sliding contact with vane storage slit groove 5 can be reduced and wear of vane 7 and vane storage slit groove 5 can be suppressed. Furthermore, because corner K of vane 7 that comes into sliding contact with vane storage slit groove 5 forms the surface of notch 7 into a convexly curved surface, no additional member is required and the pump can be manufactured more simply than conventional pumps in which additional reinforcing members are attached to the corners of the vane.

[0025] Further, notch 7C has a surface along a line connecting first position 7D and second position 7E, and first position 7D is a position spaced apart from corner K along bottom surface 7D in a counter-rotational direction opposite to rotational direction C by a dimension H2 that is approximately equal to gap dimension H1 between vane 7 and vane accommodating slit groove 5 in rotational direction C, and second position 7E is a position spaced apart from corner K radially outward along side surface 7A by a dimension 7G that is 30 to 40% of a radial remaining dimension 7F of vane 7 remaining in vane accommodating slit groove 5 when vane 7 is in a state where vane 7 protrudes to the maximum from vane accommodating slit groove 5. Therefore, the surface of notch 7C of vane 7 between first position 7D and second position 7E reliably comes into sliding contact with vane accommodating slit groove 5, so that the surface pressure of vane 7 sliding in contact with vane accommodating slit groove 5 can be more reliably reduced and wear of vane 7 and vane accommodating slit groove 5 can be more reliably suppressed.

[0026] Furthermore, the surface of the notch 7C is formed into a curved surface by crowning, which allows the surface of the notch 7C to be formed into a convex curved surface with high precision.

[0027] FIG. 4 shows 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. In addition to notch 7C, vane 7 has second notch 7C1 at corner K1 where side surface 7A1 and bottom surface 7B intersect on the rear side in the rotation direction C of rotor 4. Second notch 7C1 is formed symmetrically to notch 7C across the center of vane 7 in the thickness direction, and has a surface along a line connecting second first position 7D1 and second second position 7E1, and this surface is formed into a convex curved surface with a crowning process.

[0028] The second first position 7D1 is a position spaced a distance H2 (same as H2 in FIG. 2) from the corner K1 along the bottom surface 7B in the rotational direction C. The second second position 7E1 is a position spaced a distance 7G (same as 7G in FIG. 2) from the corner K1 radially outward along the side surface 7A1. As in the first embodiment, the distance 7G is preferably in the range of 30 to 40% of the radial remaining distance 7F.

[0029] In operation, the rotor 4 is rotated to suck in and discharge fluid, as in the first embodiment. As in the first embodiment, this operation forms the surface of the notch 7 at the corner K of the vane 7 that slides against the vane storage slit groove 5 into a convex, convex curved surface. This eliminates the need for additional components, simplifying manufacturing compared to conventional pumps that require additional reinforcing members to be attached to the vane corners. Furthermore, the surface of the notch 7C between the first position 7D and the second position 7E of the vane 7 slides against the vane storage slit groove 5, further reducing the surface pressure of the vane 7 that slides against the vane storage slit groove 5 and further reducing wear on the vane 7 and the vane storage slit groove 5. The surface of the notch 7C is also formed into a curved surface by crowning. This allows the surface of the notch 7C to be precisely formed into a convex, convex curved surface.

[0030] Furthermore, vane 7 has second notch 7C1 formed symmetrically to notch 7C across the center in the thickness direction. Therefore, vane 7 may be inserted into vane-storing slit groove 5 with either notch 7C or second notch 7C1 facing forward in rotation direction C, preventing incorrect assembly of vane 7 and allowing for easy assembly of the pump.

[0031] Furthermore, when the rotor 4 rotates in the rotation direction C, the surface of the notch 7C of the vane 7 comes into sliding contact with the vane accommodating slit groove 5, and when the vane 7 rotates in the counter-rotation direction opposite to the rotation direction C, the surface of the second notch 7C1 comes into sliding contact with the vane accommodating slit groove 5. Therefore, the notch 7C or the second notch 7C1 of the vane 7 can come into sliding contact with the vane accommodating slit groove 5 in either rotation direction of the rotor 4, making it suitable for use in pumps with both rotation directions.

[0032] In the above embodiment, the pump is of a variable displacement type in which the discharge amount becomes approximately zero when the discharge pressure reaches the full cutoff pressure, but it is of course also possible to use a fixed displacement type in which the discharge amount is approximately constant. [Explanation of symbols]

[0033] 1: Pump body 4: Rotor 5: Slit groove for storing vanes 7: Vane 7A: Side 7B: Bottom 7C: Notch 9: Cam surface 10: Pump room 11: Intake port 12: Discharge port K: Corner

Claims

1. a cam surface surrounding the outer periphery of the rotor and against which the tips of the vanes slide; a pump chamber defined by the rotor, the vanes, and the cam surface, the volume of which changes with the rotation of the rotor to suck in and discharge fluid; an intake port opening into an intake region where the volume of the pump chamber expands in response to the rotation of the rotor; and a discharge port opening into a discharge region where the volume of the pump chamber contracts in response to the rotation of the rotor;

2. 2. The vane pump according to claim 1, wherein the notch has the surface along a line connecting a first position and a second position, the first position being a position spaced apart from the corner along the bottom surface in a counter-rotational direction opposite to the rotational direction by a dimension substantially equal to a gap dimension between the vane and the vane accommodating slit groove in the rotational direction, and the second position being a position spaced apart from the corner along the side surface radially outwardly by a dimension that is 30 to 40% of a radial remaining dimension of the vane remaining in the vane accommodating slit groove when the vane is in a state where it protrudes to its maximum from the vane accommodating slit groove.

3. 3. The vane pump according to claim 1, wherein the curved surface of the notch is formed by crowning.

Images