Vane pump

Abstract

To provide a vane pump excellent in a ripple effect of slide assistance of a vane using the back pressure of another vane.SOLUTION: A vane pump 1 includes: a pump casing 10 including a pump chamber 14 defied by a cam surface 12; a rotor 20 having an outer peripheral surface 21 confronting the cam surface 12, and N slits 22 formed on the outer peripheral surface 21; and N vanes 30 each slidably arranged in the N slits 22. When the number of a top clearance 11 in which a distance between the cam surface 12 and the outer peripheral surface 21 of the rotor 20 becomes minimum is n, the rotor 20 includes a communication passage 60 for communicating M slits 22 corresponding to M vanes 30 having different phases. The N is an integral number not a prime number, and satisfies N>n, and the M is a prime factor of the N and satisfies M<N.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to vane pumps. [Background technology]

[0002] Conventionally, there has been known a vane pump that includes a rotor having an outer peripheral surface that faces a cam surface of a pump chamber, and a plurality of vanes that are respectively arranged in a plurality of slits formed in the outer peripheral surface of the rotor.

[0003] Patent Document 1 describes a vane-type compressor in which vanes are provided in a rotor so as to be able to freely protrude and retract into multiple vane slits, and grooves (communicating grooves) are provided to connect the vane slits to a shaft hole or other vane slits. In the vane-type compression device described in Patent Document 1, when the vane slit attempts to become negative pressure as the vane protrudes, fluid flows into it from the shaft hole or from another vane slit through the communicating groove, promoting the protrusion of the vane. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5554124 specification Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the vane pump described in Patent Document 1, the arrangement of the communication grooves does not take into consideration the phase relationship of the vanes, and there are unnecessary communication grooves that do not substantially contribute to assisting the sliding of the vanes. Therefore, the volume (dead volume) of the communication grooves that do not substantially contribute to assisting the sliding of the vanes hinders the ripple effect of assisting the sliding of the vanes using the back pressure of other vanes.

[0006] In view of the above circumstances, at least some embodiments of the present invention aim to provide a vane pump with an excellent ripple effect of vane sliding assistance utilizing the back pressure of other vanes.

Means for Solving the Problems

[0007] The vane pump according to at least some embodiments of the present invention includes a pump casing including a pump chamber defined by a cam surface, a rotor having an outer peripheral surface facing the cam surface and having N slits formed in the outer peripheral surface, N vanes slidably disposed in the N slits respectively, and is provided with when the number of top clearances where the distance between the cam surface and the outer peripheral surface of the rotor is minimized is n, the rotor includes a communication passage that communicates M slits corresponding to M vanes having different phases from each other, N is an integer that is not a prime number and satisfies N > n, M is a prime factor of N and satisfies M < N.

Effects of the Invention

[0008] In at least some embodiments of the present invention, since the number of vanes N is an integer that is not a prime number and satisfies N > n, there are a plurality of groups of M vanes in which a phase relationship that enables assisting the sliding of the vanes by utilizing the back pressure of other vanes is established. If the M slits corresponding to these M vanes are communicated with each other by a communication passage, it is possible to form a plurality of groups of M vanes in which a phase relationship that enables assisting the sliding of the vanes by utilizing the back pressure of other vanes is established. In this case, compared with the case where all N slits are communicated with each other, unnecessary communication passages that do not substantially contribute to assisting the sliding of the vanes by utilizing the back pressure of other vanes can be omitted, and the dead volume can be reduced. Therefore, the ripple effect of assisting the sliding of the vanes by utilizing the back pressure of other vanes can be enhanced, and the followability of the vanes can be improved.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a diagram showing an internal structure of a vane pump according to one embodiment. [Diagram 2] FIG. 1 is an axial cross-sectional view of a vane pump according to one embodiment. [Figure 3A] FIG. 1 is a diagram illustrating an internal structure of a vane pump according to an embodiment of the present invention; [Figure 3B] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3C] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3D] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3E] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3F] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3G] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3H] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3I] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 3J] FIG. 13 is a diagram illustrating an internal structure of a vane pump according to another embodiment of the present invention. [Figure 4A] 3B is a perspective view showing the structural example of the vane pump shown in FIG. 3A, as viewed from one rotor end face side. FIG. [Figure 4B] 3B is a perspective view showing the structural example of the vane pump shown in FIG. 3A, as viewed from the other rotor end face side. FIG. [Figure 4C] 3B is a graph showing the relationship between the lift amount of the vane and the angular position of the rotor in the vane pump shown in FIG. 3A. [Figure 5A] FIG. 3E is a perspective view showing an example of the structure of the vane pump shown in FIG. 3D, as viewed from one rotor end face side. [Figure 5B] 3E is a perspective view showing an example of the structure of the vane pump shown in FIG. 3D, as viewed from the other rotor end face side. FIG. [Figure 5C] 3E is a graph showing the relationship between the lift amount of the vane and the angular position of the rotor in the vane pump shown in FIG. 3D. [Figure 6A] 3E is a perspective view showing an example of the structure of the vane pump shown in FIG. 3E, as viewed from one rotor end face side. FIG. [Figure 6B] 3E, as viewed from the other rotor end face side. FIG. [Figure 6C] 3E is a graph showing the relationship between the lift amount of the vane and the angular position of the rotor in the vane pump shown in FIG. 3E. [Figure 7A] 3H , as viewed from one rotor end face side. FIG. [Figure 7B] 3H , as viewed from the other rotor end face side. FIG. [Figure 7C] 3C is a graph showing the relationship between the lift amount of the vanes and the angular position of the rotor in the vane pump shown in FIG. 3H. [Figure 8] 3E is a perspective cross-sectional view showing a structural example of a rotor of the vane pump shown in FIG. 3E. [Figure 9] 1 is a schematic exploded perspective view showing an overall structure of a vane pump according to one embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention. In this specification, unless otherwise specified, "axial direction" and "radial direction" refer to the axial direction and radial direction of the vane pump.

[0011] Fig. 1 is a diagram showing an internal structure of a vane pump according to an embodiment of the present invention, Fig. 2 is an axial cross-sectional view of the vane pump according to an embodiment of the present invention.

[0012] In some embodiments, as shown in Figures 1 and 2, the vane pump 1 includes a pump casing 10, a rotor 20 rotatably mounted within the pump casing 10, and vanes 30 each slidably arranged in a plurality of slits 22 formed in the outer peripheral surface of the rotor 20.

[0013] The pump casing 10 has a pump chamber 14 in which the rotor 20 is housed. The pump chamber 14 is defined by a cam surface 12 which is the inner peripheral surface of the pump casing 10. The cam surface 12 is defined by a contour 13 which is a smooth curve. The contour 13 is non-circular or circular. 1, the contour 13 is elliptical, and the center of rotation O of the rotor 20 coincides with the center of the ellipse of the contour 13. In other embodiments, the contour 13 is circular, and the center of the circle of the contour 13 is offset from the center of rotation O of the rotor 20.

[0014] In some embodiments, as shown in FIG. 2, the pump casing 10 includes a first member 10A having a cam surface 12 on its inner circumference, a second member 10B attached to the first member 10A to close the opening of the pump chamber 14, and a third member 10C located on the opposite side of the second member 10B across the first member 10A in the axial direction. The first member 10A has a recess that serves as the space for the pump chamber 14, and the inner circumferential wall of the recess of the first member 10A is the cam surface 12. A bottom surface 16 of the recess of the first member 10A is connected to the cam surface 12 and extends radially inward from the cam surface 12 along a plane perpendicular to the central axis of the rotor 20. One axial end surface 17 of the second member 10B faces the bottom surface 16 of the recess of the first member 10A across the pump chamber 14 in the axial direction.

[0015] At least one intake port 40 and at least one exhaust port 50 communicate with the pump chamber 14 . In the exemplary embodiment shown in FIG. 1, a pair of intake ports 40 (40A, 40B) communicate with the pump chamber 14 on both sides of the center O of the rotor 20, and a pair of exhaust ports 50 (50A, 50B) communicate with the pump chamber 14 on both sides of the center O of the rotor 20. The intake port 40A and the corresponding exhaust port 50A are arranged on both sides of a top clearance 11A. Similarly, the intake port 40B and the corresponding exhaust port 50B are arranged on both sides of a top clearance 11B. The top clearance 11 (11A, 11B) is a portion where the gap (clearance) between the cam surface 12 of the pump casing 10 and the outer circumferential surface 21 of the rotor 20 is minimum, and will be described in detail later.

[0016] 2, the rotor 20 is connected to a motor (not shown) via a rotor shaft 26, and is configured to be rotatable around a center O within the pump chamber 14. The rotor shaft 26 is inserted into a shaft hole 28 provided in the rotor 20, and is fixed to the rotor 20 via an engagement portion 29. The rotor shaft 26 is rotatably supported by a third member 10C of the pump casing 10 via a bearing 27.

[0017] 1 and 2, the rotor 20 has an outer peripheral surface 21 defined by a circular contour centered at point O. The gap G between the cam surface 12 of the pump casing 10 and the outer peripheral surface 21 of the rotor 20 is smallest at the top clearance 11 (11A, 11B) as shown in Fig. 1. The number n of top clearances is an integer equal to or greater than 1, and in the example shown in Fig. 1, n=2.

[0018] 1, N slits 22 are formed in the outer circumferential surface 21 of the rotor 20. N is an integer that is not a prime number and is greater than the number n of the top clearances (i.e., N>n is satisfied). In the example shown in FIG. 1, the number N of the slits 22 is six, and six slits 22 are formed in the outer circumferential surface 21 of the rotor 20 at equal intervals in the circumferential direction.

[0019] The extension direction of each slit 22 may be inclined relative to the radial direction of the rotor 20, such that it extends toward the downstream side in the rotation direction of the rotor 20 as it approaches the end 24 of the slit 22 on the radial inner side of the rotor 20 toward the opening end of the slit 22 on the outer peripheral surface 21. In the example shown in FIG. 1, the rotation direction of the rotor 20 is counterclockwise, and each slit 22 is inclined relative to the radial direction so as to move toward the downstream side (counterclockwise) of the rotation direction of the rotor 20 as it approaches the opening end on the outer peripheral surface 21 from the radially inner end 24.

[0020] The N slits 22 are each provided with N vanes 30 capable of reciprocating within the slits 22 . Each vane 30 slides on the cam surface 12 while being pressed against the cam surface 12 of the pump chamber 14 by centrifugal force caused by the rotation of the rotor 20. The protruding length of each vane 30 from the outer circumferential surface 21 changes periodically according to the rotation phase of the rotor 20. In the example shown in Figure 1, when each of the six vanes 30 passes through a pair of top clearances 11 (11A, 11B), the protruding length of the vane 30 from the outer peripheral surface 21 is minimum (which may be zero), and the protruding length of the vane 30 from the outer peripheral surface 21 is maximum at the intermediate angular position between the pair of top clearances 11 (11A, 11B).

[0021] Between a pair of vanes 30 adjacent to each other in the circumferential direction, a chamber 15 is defined by the pair of vanes 30, the cam surface 12, and the outer circumferential surface 21 of the rotor 20. The number of chambers 15 is equal to the number N of the vanes 30. 1, the pump chamber 14 is divided into six compartments 15 by six vanes 30. When a pair of vanes 30 that define the compartments 15 move in the circumferential direction due to the rotation of the rotor 20, the compartments 15 also move in the circumferential direction while repeatedly contracting and expanding in volume.

[0022] When the compartment 15 reaches the opening position of the intake port 40 (40A, 40B), the volume of the compartment 15 tends to expand, and gas is taken into the compartment 15 from the intake port 40. After this, the volume of the compartment 15 continues to expand for a while as the compartment 15 moves in the circumferential direction, but as the compartment 15 approaches the opening position of the exhaust port 50 (50A, 50B), the volume of the compartment 15 begins to decrease. When the compartment 15 reaches the opening position of the exhaust port 50 (50A, 50B), the volume of the compartment 15 tends to decrease, and so the gas within the compartment 15 is discharged from the exhaust port 50. In this manner, the gas sucked into the vane pump 1 through the intake port 40 is discharged through the exhaust port 50.

[0023] In the exemplary embodiment shown in FIG. 1, each vane 30 has a tip surface 31 that is oblique to the longitudinal direction of the vane 30 (the extension direction of the slits 22). The tip surface 31 has a contact portion 33 that comes into contact with the cam surface 12 downstream in the rotation direction of the rotor 20. A portion of the tip surface 31 upstream of the contact portion 33 in the rotation direction is set back from the cam surface 12 with respect to the contact portion 33, forming a gap between the tip surface 31 and the cam surface 12. In the vane 30 having such an inclined tip surface 31, the vane length is not constant in the thickness direction of the vane 30, and the vane length increases toward the downstream side in the rotation direction of the rotor 20.

[0024] 1, the rotor 20 includes a plurality of communication passages 60 that communicate with each other among the M slits 22 corresponding to the M vanes 30 that are out of phase with each other. Each of the communication passages 60 may not communicate with the shaft hole 28. In one embodiment, the communication passage 60 is a groove provided in at least one end face (62, 64) of the rotor 20 in the axial direction. Here, the end face 62 of the rotor 20 is the face of the rotor 20 facing the bottom face 16 of the recess of the first member 10A of the pump casing 10, and the end face 64 of the rotor 20 is the face of the rotor 20 facing the axial end face 17 of the second member 10B of the pump casing 10. In another embodiment, the communication passage 60 is a communication hole provided inside the rotor 20.

[0025] Next, with reference to Figs. 3A to 3J, the relationship between the total number N of slits 22 (vanes 30), the number n of top clearances 11, and the number M of slits 22 that communicate with each other through communication passages 60 will be described. 3A to 3J are each a schematic diagram showing an internal structure of a vane pump 1 according to one embodiment.

[0026] 3A to 3J, in order to distinguish the phase relationship between groups of M vanes 30 corresponding to M slits 22 connected by the communication paths 60, dashed lines of a plurality of types of communication paths 60 are used. The phase relationships between the groups of M vanes 30, whose communication passages 60 are shown by a common dashed line, are consistent (however, the phases of the vanes 30 within each group are different from each other). In this case, for each of the M vanes 30 belonging to one group, there is a vane 30 of substantially the same phase among the M vanes 30 belonging to the other group. In contrast, the phase relationships between groups of M vanes 30 whose communication passages 60 are illustrated by different types of dashed lines are shifted from each other. In this case, as a whole group, the M vanes 30 belonging to one group are offset in phase with respect to the M vanes 30 belonging to the other group. Therefore, for each of the M vanes 30 belonging to one group, there is no vane 30 that is substantially in phase with the M vanes 30 belonging to the other group.

[0027] In some embodiments, as shown in FIGS. 3A and 3B, the vane pump 1 (1A, 1B) has one top clearance 11 (n=1). The vane pumps 1A and 1B are unbalanced vane pumps in which the pressure around the rotor 20 in the pump chamber 14 is asymmetric with respect to the center O (see FIG. 1). In the vane pumps 1A and 1B, each vane 30 slides one period in the slit 22 while the rotor 20 rotates once. Specifically, when the vane 30 passes through one top clearance 11, most of the vane 30 is accommodated inside the slit 22, and when the vane 30 reaches a circumferential position geometrically opposite the top clearance 11 with the center O of the rotor 20 in between, the amount of protrusion of the vane 30 from the slit 22 becomes maximum.

[0028] In another embodiment, as shown in FIGS. 3C to 3G, the vane pump 1 (1C to 1G) has two top clearances 11 (n=2). The vane pumps 1C to 1G are balanced vane pumps in which the pressure around the rotor 20 in the pump chamber 14 is symmetrical with respect to the center O (see FIG. 1). In the vane pumps 1C to 1G, each vane 30 slides in the slit 22 for two periods while the rotor 20 rotates once. Specifically, when the vane 30 passes through each top clearance 11, most of the vane 30 is accommodated inside the slit 22, and when the vane 30 reaches a circumferential position midway between the two top clearances 11, the amount of protrusion of the vane 30 from the slit 22 becomes maximum.

[0029] In still another embodiment, as shown in FIGS. 3H to 3J, the vane pump 1 (1H to 1J) has three top clearances 11 (n=3). The vane pumps 1H to 1J are unbalanced vane pumps in which the pressure around the rotor 20 in the pump chamber 14 is asymmetric with respect to the center O (see FIG. 1). In the vane pumps 1H to 1J, each vane 30 slides three periods in the slit 22 while the rotor 20 makes one rotation. When the vane 30 passes through each top clearance 11, most of the vane 30 is accommodated inside the slit 22, and when the vane 30 reaches a circumferential position midway between the pair of top clearances 11, the amount of protrusion of the vane 30 from the slit 22 becomes maximum.

[0030] In some embodiments, in the vane pumps 1 (1A - 1D, 1F, 1H, 1I) shown in FIGS. 3A - 3I, the total number N of slits 22 (vanes 30) is an integer that is not a prime number and is greater than the number n of top clearances 11 (N > n). Also, the number M of slits 22 that communicate with each other through the communication passages 60 is a prime factor of N and satisfies M < N. In the vane pumps 1 (1A - 1C, 1H, 1I) shown in FIGS. 3A - 3C, 3E, 3G - 3I, the number M of slits 22 that communicate with each other through the communication passages 60 is the minimum value of the prime factors of the total number N of slits 22 (vanes 30). In the embodiments shown in FIGS. 3D and 3F, for the vane pumps 1 (1D, 1F), the minimum value of the prime factors of the total number N of slits 22 (vanes 30) is a divisor of the number n of top clearances 11. Also, the number M of slits 22 that communicate with each other through the communication passages 60 is the minimum value of the prime factors of N excluding the divisors of n.

[0031] In the example of the vane pump 1A shown in FIG. 3A, N = 4, M = 2, and n = 1. The set of prime factors of N is {2}. The set of divisors of n is {1}. In FIG. 3A, a total of two communication passages 60 are shown distinguished by two types of dashed lines. In the vane pump 1A, the phase relationships between two groups each consisting of two vanes 30 are shifted from each other.

[0032] In the example of the vane pump 1B shown in FIG. 3B, N = 6, M = 2, and n = 1. The set of prime factors of N is {2, 3}. The set of divisors of n is {1}. In FIG. 3B, a total of three communication passages 60 are shown distinguished by three types of dashed lines. In the vane pump 1B, the phase relationships between three groups each consisting of two vanes 30 are shifted from each other.

[0033] In the example of the vane pump 1C shown in FIG. 3C, N=4, M=2, and n=2. The set of prime factors of N is {2}. The set of divisors of n is {1, 2}. In FIG. 3C, a total of two communication passages 60 are illustrated by the same type of dashed line. In the vane pump 1C, the phase relationship between the two groups each consisting of two vanes 30 is consistent.

[0034] In the example of the vane pump 1D shown in FIG. 3D, N=6, M=3, and n=2. The set of prime factors of N is {2, 3}. The set of divisors of n is {1, 2}. The set of prime factors of N excluding the divisors of n is {3}. In FIG. 3D, a total of four communication passages 60 are shown by the same type of dashed lines. In the vane pump 1D, the phase relationship between two groups of three vanes 30 is consistent.

[0035] In the example of the vane pump 1E shown in FIG. 3E, N=8, M=2, and n=2. The set of prime factors of N is {2}. The set of divisors of n is {1, 2}. In FIG. 3E, a total of four communication passages 60 are illustrated and distinguished by two types of dashed lines. In the vane pump 1E, for each of the four groups consisting of two vanes 30, there is one group whose phase relationship matches that of the group.

[0036] In the example of the vane pump 1F shown in FIG. 3F, N=10, M=5, and n=2. The set of prime factors of N is {2, 5}. The set of divisors of n is {1, 2}. The set of prime factors of N excluding the divisors of n is {5}. In FIG. 3F, a total of eight communication passages 60 are shown by the same dashed lines. In the vane pump 1F, the phase relationship between two groups of five vanes 30 is consistent.

[0037] In the example of the vane pump 1G shown in FIG. 3G, N=12, M=2, and n=2. The set of prime factors of N is {2, 3}. The set of divisors of n is {1, 2}. In FIG. 3G, a total of six communication passages 60 are illustrated, distinguished by three types of dashed lines. In the vane pump 1G, for each of the six groups consisting of two vanes 30, there is one group whose phase relationship matches that of the group.

[0038] In the example of the vane pump 1H shown in FIG. 3H, N=6, M=2, and n=3. The set of prime factors of N is {2, 3}. The set of divisors of n is {1, 3}. In FIG. 3H, a total of three communication passages 60 are shown by the same type of dashed lines. In the vane pump 1H, the phase relationships between the three groups of two vanes 30 are consistent.

[0039] In the example of the vane pump 1I shown in FIG. 3I, N=9, M=3, and n=3. The set of prime factors of N is {3}. The set of divisors of n is {1, 3}. In FIG. 3I, a total of six communication passages 60 are shown by the same dashed lines. In the vane pump 1I, the phase relationships between the three groups of three vanes 30 are consistent.

[0040] In the example of the vane pump 1J shown in FIG. 3J, N=12, M=2, and n=3. The set of prime factors of N is {2, 3}. The set of divisors of n is {1, 3}. In FIG. 3J, a total of six communication passages 60 are illustrated and distinguished by two types of dashed lines. In the vane pump 1J, for each of the six groups consisting of two vanes 30, there is one group whose phase relationship matches that of the group.

[0041] Figures 4A and 4B are perspective views showing a structural example of the vane pump 1A, where Figure 4A is a view seen from one rotor end face 62 side, and Figure 4B is a view seen from the other rotor end face 64 side. Figure 4C is a graph showing the relationship between the protrusion amount (lift amount) of each vane 30 from the slit 22 in the vane pump 1A and the angular position of the rotor 20. As shown in FIG. 4A and FIG. 4B, the vane pump 1A has one top clearance 11, four slits 22 (vanes 30), and a total of two communication passages 60 that communicate two slits 22 corresponding to two vanes 30 with different phases. That is, the vane pump 1A satisfies N=4, M=2, and n=1. As shown in FIG. 4B and FIG. 4C, the vane pump 1A has two groups (Gr1, Gr2) of two vanes 30 that move substantially in opposite phases. The two vanes 30 belonging to each group (Gr1, Gr2) slide in the slits 22 for one cycle while maintaining substantially opposite phases with each other during one rotation of the rotor 20 (angle range of 0° to 360°). The group Gr1 and the group Gr2 are out of phase with each other as a whole group. For this reason, in FIG. 3A, the two communication passages 60 of the vane pump 1A are illustrated by using two kinds of dashed lines to distinguish them from each other. In this way, in the vane pump 1A, a pair of slits 22 corresponding to two vanes 30 whose lift amounts are substantially in opposite phase to each other are communicated with each other through the communication passage 60. When one of the slits 22 is about to become negative pressure due to the vane 30 protruding, fluid moves between the other slit 22 which is about to become positive pressure due to the vane 30 retracting, via the communication passage 60. As a result, the pressure drop in one of the slits 22 is at least partially offset by the pressure increase in the other slit 22, promoting the sliding of the vanes 30.

[0042] Figures 5A and 5B are perspective views showing a structural example of a vane pump 1D, where Figure 5A is a view seen from one rotor end face 62 side, and Figure 5B is a view seen from the other rotor end face 64 side. Figure 5C is a graph showing the relationship between the protrusion amount (lift amount) of each vane 30 from the slit 22 in the vane pump 1D and the angular position of the rotor 20. As shown in FIG. 5A and FIG. 5B, the vane pump 1D has two top clearances 11, six slits 22 (vanes 30), and a total of four communication passages 60 that communicate the three slits 22 corresponding to the three vanes 30 that are out of phase with each other. That is, the vane pump 1D satisfies N=6, M=3, and n=2. As shown in FIG. 5A and FIG. 5C, the vane pump 1D has two groups (Gr1, Gr2) of three vanes 30 having a phase difference of about 60° or about 120°. The three vanes 30 belonging to each group (Gr1, Gr2) slide in the slits 22 for two periods while maintaining a phase difference of about 60° or about 120° during one rotation of the rotor 20 (angle range of 0° to 360°). The phase relationship of the group Gr1 and the group Gr2 as a whole is the same. For this reason, in FIG. 3D, the six communication passages 60 (two groups) of the vane pump 1D are illustrated using one type of dashed line without distinction. In this way, in the vane pump 1D, three slits 22 corresponding to three vanes 30 with lift amounts shifted by approximately 60° or approximately 120° are connected to each other through a total of four communication passages 60 (two for each group Gr1, Gr2). In each group (Gr1, Gr2), when one slit 22 is about to become negative pressure due to the vane 30 protruding, fluid moves between the remaining two slits 22, which are about to become positive pressure due to the vane 30 retracting, through the communication passages 60. Therefore, the pressure drop in one slit 22 is at least partially offset by the pressure increase in the remaining two slits 22, promoting the sliding of the vanes 30.

[0043] Figures 6A and 6B are perspective views showing a structural example of a vane pump 1E, where Figure 6A is a view seen from one rotor end face 62 side, and Figure 6B is a view seen from the other rotor end face 64 side. Figure 6C is a graph showing the relationship between the protrusion amount (lift amount) of each vane 30 from the slit 22 in the vane pump 1E and the angular position of the rotor 20. As shown in FIG. 6A and FIG. 6B, the vane pump 1E has two top clearances 11, eight slits 22 (vanes 30), and a total of four communication passages 60 that communicate two slits 22 corresponding to two vanes 30 that are out of phase with each other. That is, the vane pump 1E satisfies N=8, M=4, and n=2. As shown in FIG. 6A to FIG. 6C, the vane pump 6D has four groups (Gr1, Gr2, Gr3, Gr4) of two vanes 30 that are substantially out of phase with each other. The two vanes 30 belonging to each group (Gr1 to Gr4) slide in the slits 22 for two periods while maintaining out of phase with each other during one rotation of the rotor 20 (angle range of 0° to 360°). The group Gr1 and the group Gr2 have the same phase relationship as the whole group. The group Gr3 and the group Gr4 have the same phase relationship as the whole group. In contrast, the phase relationship between group Gr1 (Gr2) and group Gr3 (Gr4) as a whole group is shifted from each other. For this reason, in Fig. 3E, two types of dashed lines are used to distinguish the four communication passages 60 of the vane pump 1E into groups having different phase relationships. In this way, in the vane pump 1E, a pair of slits 22 corresponding to two vanes 30 whose lift amounts are substantially in opposite phase to each other are communicated with each other through the communication passage 60. When one of the slits 22 is about to become negative pressure due to the vane 30 protruding, fluid moves between the pair of slits 22 and the other slit 22 which is about to become positive pressure due to the vane 30 retracting, via the communication passage 60. As a result, the pressure drop in one of the slits 22 is at least partially offset by the pressure increase in the other slit 22, promoting the sliding of the vanes 30.

[0044] Figures 7A and 7B are perspective views showing a structural example of a vane pump 1H, where Figure 7A is a view seen from one rotor end face 62 side, and Figure 7B is a view seen from the other rotor end face 64 side. Figure 7C is a graph showing the relationship between the protrusion amount (lift amount) of each vane 30 from the slit 22 in the vane pump 1H and the angular position of the rotor 20. As shown in FIG. 7A and FIG. 7B, the vane pump 1H has three top clearances 11, six slits 22 (vanes 30), and a total of three communication passages 60 that communicate two slits 22 corresponding to two vanes 30 that are out of phase with each other. That is, the vane pump 1H satisfies N=6, M=2, and n=3. As shown in FIG. 7A and FIG. 7C, the vane pump 1H has three groups (Gr1, Gr2, Gr3) of two vanes 30 that move substantially in opposite phases. The two vanes 30 belonging to each group (Gr1, Gr2, Gr3) slide in the slits 22 for three periods while maintaining substantially opposite phases with each other during one rotation of the rotor 20 (angle range of 0° to 360°). The three groups Gr1 to Gr3 have the same phase relationship as the whole group. For this reason, in FIG. 3H, one type of dashed line is used to illustrate the three communication passages 60 (three groups) of the vane pump 1H without distinction. In this way, in the vane pump 1H, a pair of slits 22 corresponding to two vanes 30 whose lift amounts are substantially in opposite phase to each other are communicated with each other through the communication passage 60. When one of the slits 22 is about to become negative pressure due to the vane 30 protruding, fluid moves between the other slit 22 which is about to become positive pressure due to the vane 30 retracting, via the communication passage 60. As a result, the pressure drop in one of the slits 22 is at least partially offset by the pressure increase in the other slit 22, promoting the sliding of the vanes 30.

[0045] In some embodiments, as shown in Figures 4B, 5A, 6A, 6B, and 7A, each communication passage 60 extends linearly between a pair of slits 22 among the M slits 22, and connects the pair of slits 22. The communication passage 60 includes one or more communication grooves 66 formed by grooves provided in at least one end face (62, 64) of the rotor 20 in the axial direction of the vane pump 1. In this case, a plurality of communication grooves 66 may be formed in a distributed manner on the pair of axial end faces 62, 64 of the rotor 20. In the embodiment shown in Figures 6A and 6B, the four communication grooves 66 of the vane pump 1E are formed in a distributed manner, two grooves on each of the axial end faces 62, 64 of the rotor 20. The communication passage 60 may take the form of a communication hole 68 provided inside the rotor 20, other than the communication groove 66. In some embodiments, at least one communication passage 60 is a communication hole 68 that extends inside the rotor 20 between a pair of slits 22 among the M number of slits 22 and communicates the pair of slits 22 with each other. In the vane pump 1A, as shown in FIG. 4B, the shaft hole 28 does not penetrate the rotor 20, and one communication hole 68 is provided inside the rotor 20 so as to pass through an axial position between the shaft hole 28 and an end face 64 of the rotor 20. A communication groove 66 is provided in the end face 64 of the rotor 20 along a direction perpendicular to the communication hole 68.

[0046] Fig. 8 is a perspective cross-sectional view showing a structural example of the rotor 20 of a vane pump 1E different from Fig. 6A and Fig. 6B. Note that in Fig. 8, the vanes 30 are omitted and only the rotor 20 is shown, and the slits 22 corresponding to the vanes 30 of four groups (Gr1 to Gr4) are given reference characters for identifying the groups. The vane pump 1E shown in Fig. 8 is common to the example shown in Fig. 6A and Fig. 6B, except for whether each communication passage 60 is constituted by a communication groove 66 or a communication hole 68. In the embodiment shown in the figure, all of the four communication passages 60 of the vane pump 1E are formed by communication holes 68. Specifically, a first pair of communication holes 68 communicate two pairs of slits 22 at the same axial position, and a second pair of communication holes 68 communicates the other two pairs of slits 22 at another axial position.

[0047] In some embodiments, as shown in Figures 6A, 6B, and 8, a communication passage 60 (first communication passage) that connects two of the M slits 22 belonging to the first group (Gr1 or Gr2) passes between one of the M slits 22 belonging to the second group (Gr3 or Gr4) and the shaft hole 28. State.

[0048] FIG. 9 is a schematic exploded perspective view showing the overall structure of a vane pump 1 according to one embodiment. The vane pump 1 exemplarily shown in Fig. 9 may be a vacuum pump. For example, the vane pump 1 may be a vane-type electric vacuum pump for creating a negative pressure in a negative pressure chamber of a brake booster (master back) in a vehicle such as an automobile. In the following description, "upper" and "lower" refer to the "upper" and "lower" states when the vane pump 1 is installed in a vehicle.

[0049] 9, the vane pump 1 includes a pump casing 10 and a rotor 20 rotatably provided within the pump casing 10. The rotor 20 is driven by a motor 80 provided below the pump casing 10, and rotates around a center O.

[0050] The pump casing 10 has a pump chamber 14 in which a rotor 20 is housed. The pump chamber 14 is defined by a cam surface 12, which is the inner circumferential surface of the pump casing 10. The cam surface 12 is defined by a contour 13 that may be circular or non-circular.

[0051] The rotor 20 has an outer peripheral surface 21 defined by a circular contour centered at point O. A plurality of slits 22 are formed in the outer peripheral surface 21. Each slit 22 is provided with a vane 30 that divides the pump chamber 14 into a plurality of compartments 15 (see FIG. 1). Each slit 22 communicates with one or more other slits 22 via a communication passage 60. The number n of top clearances 11 (see Figure 1) formed between the cam surface 12 and the outer peripheral surface 21 of the rotor 20, the total number N of slits 22 (vanes 30), and the number M of slits 22 connected to each other by the communicating passages 60 satisfy at least one of the relationships described with reference to Figures 3A to 7C.

[0052] In the example shown in Figure 9, the pump casing 10 includes a pump casing body 70 having a recess that forms the bottom and side surfaces of the pump chamber 14 in which the rotor 20 is housed, and a pump cover 72 that forms the top surface of the pump chamber 14. A top cover 74 that covers the pump cover 72 is provided above the pump cover 72. A bottom cover 76 that covers the underside of the pump casing body 70 is provided between the pump casing body 70 and the motor 80.

[0053] The bottom cover 76 has an intake port 90 through which gas flows into the pump chamber 14 . The intake port 90 is led to an intake passage 93 formed between the pump cover 72 and the top cover 74 via a communication passage 91A provided in the pump casing body 70 and a communication passage 91B provided in the pump cover 72. The communication passage 91B penetrates the pump cover 72, and the gas that has passed through the communication passage 91A provided in the pump casing body 70 flows through the communication passage 91B into the intake passage 93 formed above the pump cover 72. The intake passage 93 is in communication with the pump chamber 14 (compartment chamber 15) via intake ports 40 (40A, 40B) provided in the pump cover 72. The intake passage 93 is fluidly isolated from an exhaust passage 95, which will be described later, by a partition portion 94 provided in the pump cover 72. The intake passage 93 surrounded by the partition portion 94 extends from the communication passage 91B toward the opposite side across the center O of the rotor 20 in the radial direction of the rotor 20 so as to communicate with the pump chamber 14 (compartment chamber 15) via a pair of intake ports 40A, 40B located on opposite sides across the center O of the rotor 20. As a result, gas from the intake port 90 is taken into the pump chamber 14 (compartment chamber 15) via the intake port 40 (40A, 40B) that opens into the pump chamber 14 near the top clearance 11 (see FIG. 1).

[0054] The pump cover 72 has an exhaust port 92 which is an outlet for the gas flow exhausted from the pump chamber 14 . The exhaust port 92 communicates with an exhaust passage 95 formed between the pump cover 72 and the top cover 74. As described above, the exhaust passage 95 is fluidically isolated from the intake passage 93 by the partition wall portion 94 surrounding the intake passage 93. The pump cover 72 has a communication passage 96 that communicates with the exhaust passage 95. The communication passage 96 of the pump cover 72 communicates with the pump chamber 14 (partitioned chamber 15) via a communication passage 97 provided in the pump casing body 70 and exhaust ports 50 (50A, 50B) that open into the bottom surface of the recess of the pump casing body 70 that forms the pump chamber 14. Note that FIG. 8 only shows the exhaust port 50A provided on the opposite side to the intake port 40A across the top clearance 11A (see FIG. 1). The gas discharged from the pump chamber 14 through the exhaust ports 50 (50A, 50B) flows upward along the side of the pump chamber 14 through a communication passage 97 in the pump casing body 70, and flows into an exhaust passage 95 formed above the pump cover 72 through a communication passage 96. Thereafter, the gas in the exhaust passage 95 is discharged to the outside through an exhaust port 92 that communicates with the exhaust passage 95.

[0055] The characteristic configurations of the vane pump 1 according to the above-described embodiments are summarized as follows.

[0056] [1] At least some embodiments of the vane pump (1) include: a pump casing (10) including a pump chamber (14) defined by a cam surface (12); a rotor (20) having an outer circumferential surface (21) facing the cam surface (12), and having N slits (22) formed in the outer circumferential surface (21); N vanes (30) slidably disposed in the N slits (22), comprising when the number of top clearances (11) where the distance between the cam surface (12) and the outer peripheral surface (21) of the rotor (20) is minimized is n, the rotor (20) includes a communication passage (60) that communicates M slits (22) corresponding to M vanes (30) having different phases from each other, N is an integer that is not a prime number and satisfies N > n, M is a prime factor of N and satisfies M < N.

[0057] According to the configuration of [1] above, since the number N of vanes (30) is an integer that is not a prime number and satisfies N > n, there are a plurality of groups (Gr1, Gr2) of M vanes (30) in which a phase relationship capable of assisting the sliding of the vanes (30) by utilizing the back pressure of the other vanes (30) is established. If the M slits (22) corresponding to these M vanes (30) are communicated with each other by the communication passage (60), it is possible to form a plurality of groups (Gr1, Gr2) of M vanes (30) in which a phase relationship capable of assisting the sliding of the vanes (30) by utilizing the back pressure of the other vanes (30) is established. In this case, compared with the case where all N slits are communicated with each other, unnecessary communication passages that do not substantially contribute to assisting the sliding of the vanes using the back pressure of the other vanes can be omitted, and the dead volume can be reduced. Therefore, the ripple effect of assisting the sliding of the vanes (30) by utilizing the back pressure of the other vanes (30) can be enhanced, and the followability of the vanes (30) can be improved.

[0058] [2] In some embodiments, in the configuration of [1] above, M is the minimum value of the prime factors of N

[0059] According to the configuration of [2] above, by setting M so as to be the minimum prime factor of N, the number of vanes (M) belonging to the group (Gr1~Gr4) of vanes (30) in which the slits (22) are communicated with each other by the communication passage (60) is reduced, the dead volume is further reduced, and the followability of the vanes (30) can be more effectively improved.

[0060] [3] In some embodiments, in the configuration of [1] or [2] above, The smallest prime factor of N is a divisor of n, M is the smallest prime factor of N excluding the divisors of n.

[0061] As a result of extensive investigation, the present inventor has found that when the minimum value of the prime factors of N, which are candidates for M, is a divisor of the number n of the top clearance (11), the tracking ability of the vane (30) can be effectively improved by setting M to the minimum value of the prime factors of N excluding the divisors of n. That is, in the above-mentioned case, rather than prioritizing reduction of the dead volume by setting M to the minimum value of the prime factors of N, setting M to the minimum value of the prime factors of N excluding the divisors of n makes it possible to obtain a clearer sliding assistance effect of the vane (30) utilizing the back pressure of other vanes (30) belonging to the same group, thereby improving the tracking ability of the vane (30) as a whole.

[0062] [4] In some embodiments, in any one of the configurations [1] to [3] above, Each communication passage (60) extends linearly between a pair of the slits (22) among the M number of slits (22), and brings the pair of slits (22) into communication with each other.

[0063] According to the above configuration [4], it is easier to form the communication passage (60) to the rotor (20) than in the case of a curved communication passage.

[0064] [5] In some embodiments, in any one of the configurations [1] to [4] above, The vane pump (1) includes a rotor shaft (26) that is inserted into a shaft hole (28) formed in the rotor (20) and coupled to the rotor (20); The communication passage (60) is a first communication passage (60) that communicates two first slits (22) among the M slits (22) belonging to a first group (Gr1, Gr2); a second communication passage (60) that communicates two second slits (22) among the M slits (22) belonging to the second group (Gr3, Gr4); Including, The first communication passage (60) passes between one of the second slits (22) corresponding to the vanes (30) belonging to the second groups (Gr3, Gr4) and the axial hole (28) of the rotor (20) and extends between the two first slits (22) corresponding to the vanes (30) belonging to the first groups (Gr1, Gr2) so as to connect the two first slits (22) corresponding to the vanes (30) belonging to the first groups (Gr1, Gr2) to each other.

[0065] According to the above configuration [5], it is possible to realize a layout of the first communication passage (60) that is not connected to the second slits (22) and the shaft holes (28) of the other groups (Gr3, Gr4), thereby further reducing the dead volume and more effectively improving the tracking ability of the vane (30).

[0066] [6] In some embodiments, in any one of the configurations [1] to [5] above, The communication passage (60) includes one or more communication grooves (66) formed by grooves provided in at least one end face (62, 64) of the rotor (20) in the axial direction of the vane pump (1).

[0067] According to the configuration [6] above, for example, by machining the end faces (62, 64) of the rotor (20), the communicating grooves (66) that connect the slits (22) corresponding to the M vanes (30) can be easily formed.

[0068] [7] In some embodiments, in the configuration of [6] above, A plurality of communication grooves (66) are formed distributed over a pair of end faces (62, 64) of the rotor (20) in the axial direction of the vane pump (1E).

[0069] According to the above configuration [7], the pair of axial end faces (62, 64) of the rotor (20) are used as locations for forming the communicating grooves (66), thereby improving the degree of freedom in layout of the communicating grooves (66).

[0070] [8] In some embodiments, in any one of the configurations [1] to [7] above, The communication passage (60) extends within the rotor (20) between a pair of the slits (22) of the M number of slits (22), and includes a communication hole (68) that connects the pair of slits (22) to each other.

[0071] According to the above configuration [8], the internal region of the rotor (20) can also be used to form the communication passages (60), thereby making it possible to make the rotor (20) more compact. The communication holes 68 that connect the slits 22 to each other may be formed by machining, electric discharge machining, or three-dimensional additive manufacturing.

[0072] [9] In some embodiments, in any one of the configurations [1] to [8] above, a rotor shaft (26) that is inserted into a shaft hole (28) formed in the rotor (20) and coupled to the rotor (20); The communication passage (60) does not communicate with the shaft hole (28).

[0073] According to the above configuration [9], leakage flow from the shaft hole (28) via the communication passage (60) can be prevented, and the tracking ability of the vane (30) can be improved more effectively.

[0074] In this specification, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," do not only strictly represent such a configuration, but also represent a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements. [Explanation of symbols]

[0075] 1(1A~1J): Vane pump 10: Pump casing 11(11A~11B): Top clearance 12: Cam surface 14: Pump room 20: Rotor 21: Outer surface 22: Slit 26: Rotor shaft 28: Shaft hole 30: Vane 60: Communication path 62,64: End face 66:Communication groove 68:Communication hole Gr1~Gr4: Group N: Number of slits (number of vanes) M: Number of interconnected slits (number of vanes in each group) n: Number of top clearances

Claims

1. a pump casing including a pump chamber defined by a cam surface; a rotor having an outer circumferential surface facing the cam surface, the outer circumferential surface having N slits formed thereon; N vanes slidably disposed in the N slits, respectively; Equipped with When the number of top clearances at which the distance between the cam surface and the outer circumferential surface of the rotor is minimum is n, the rotor includes communication passages that communicate the M number of slits corresponding to the M number of vanes that are out of phase with each other, N is an integer that is not a prime number, and N>n is satisfied; M is a prime factor of N, and M<N. Vane pump.

2. M is the smallest of the prime factors of N 2. The vane pump according to claim 1.

3. the smallest prime factor of N is a divisor of n, M is the smallest prime factor of N excluding the divisors of n 3. A vane pump according to claim 1 or 2.

4. Each of the communication paths extends linearly between a pair of the M number of slits and communicates the pair of slits.

3. A vane pump according to claim 1 or 2.

5. a rotor shaft that is inserted into a shaft hole provided in the rotor and coupled to the rotor; The communication passage is a first communication passage that communicates two first slits among the M number of slits belonging to a first group; a second communication passage that communicates two second slits among the M number of slits belonging to a second group; Including, The first communication passage passes between one of the second slits and the shaft hole of the rotor and extends between the two first slits so as to communicate the two first slits with each other.

3. A vane pump according to claim 1 or 2.

6. The communication passage includes one or more communication grooves formed by grooves provided in at least one end surface of the rotor in the axial direction of the vane pump.

3. A vane pump according to claim 1 or 2.

7. The plurality of communication grooves are formed in a distributed manner on a pair of end faces of the rotor in the axial direction of the vane pump.

7. A vane pump according to claim 6.

8. The communication passage extends in the rotor between a pair of the M number of slits and includes a communication hole that communicates the pair of slits with each other.

3. A vane pump according to claim 1 or 2.

9. a rotor shaft that is inserted into a shaft hole provided in the rotor and coupled to the rotor; The communication passage is not in communication with the shaft hole.

3. A vane pump according to claim 1 or 2.

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