JP2020197151A - Vane pump - Google Patents

Abstract

To improve the pump efficiency of a vane pump.SOLUTION: A vane pump 2 comprises a pump casing 10 including a pump chamber 5, a rotor 38 arranged in the pump chamber 5, and including a plurality of slits 36 at an external peripheral face 32, and a plurality of vanes 40 arranged at the plurality of slits 36. The pump chamber 5 includes an internal peripheral face 42 which is formed so that a distance L between a rotation center C of the rotor 38 and itself is changed in a peripheral direction Cd of the rotor 38. When setting an angle from a first angle position P 1 in the peripheral direction Cd in which the distance L between the internal peripheral face 42 and the rotation center C of the rotor 38 is minimum up to a second angle position P2 located at the most upstream side out of an angle position in which the distance L becomes maximum at a downstream side of the first angle position P1 in a rotation direction Rd of the rotor 38 as θ1, and setting an angle from the second angle position P2 up to a third angle position P3 located at the most upstream side out of an angle position in which the distance L becomes minimum at a downstream side of the second angle position P2 in the rotation direction Rd as θ 2, the internal peripheral face 42 satisfies a relationship of θ1<θ2/2.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to vane pumps.

Conventionally, as disclosed in Patent Document 1, for example, a vane pump for making a negative pressure chamber of a brake booster in a vehicle such as an automobile into a negative pressure is known. The vane pump includes a rotor having a slit on the outer peripheral surface and vanes arranged in the slit, and the vane slides on the cam surface while being pressed against the cam surface of the pump chamber by centrifugal force due to the rotation of the rotor. It is configured to do.

Japanese Unexamined Patent Publication No. 2015-59572

By the way, in a vane pump, since the pressure of the intake port (inlet pressure) is generally lower than the pressure of the exhaust port (outlet pressure), the fluid sucked into the pump chamber is compressed and exhausted before exhaust. However, in the conventional vane pump as disclosed in Patent Document 1, the profile of the inner peripheral surface of the pump chamber is pumped from the rotation center of the rotor and the rotation center in the direction of the rotation axis of the rotor housed in the pump chamber. The intake side that communicates with the intake passage and the exhaust side that communicates with the exhaust passage across a line (including, for example, the long axis of an ellipse) connecting the points on the inner peripheral surface that has the maximum distance to the inner peripheral surface of the chamber. And were formed in the shape of a line object (including, for example, an ellipse). In the case of such a conventional vane pump, the pressure in the pump chamber when the exhaust passage and the pump chamber communicate with each other and the exhaust starts may be less than the above outlet pressure, and the fluid temporarily flows back from the exhaust passage into the pump chamber. There was a risk that the pump efficiency would decrease. Patent Document 1 does not disclose any measures for solving such a problem.

In view of the above circumstances, at least one embodiment of the present disclosure is intended to provide a vane pump capable of improving pump efficiency.

(1) The vane pump according to at least one embodiment of the present invention is
The pump casing that forms the pump chamber and
A rotor placed in the pump chamber and having multiple slits on the outer peripheral surface,
With multiple vanes, each placed in multiple slits,
The pump chamber includes an inner peripheral surface formed so that the distance from the center of rotation of the rotor changes in the circumferential direction of the rotor.
The inner peripheral surface of the pump chamber is
The most upstream position from the first angular position in the circumferential direction where the distance between the inner peripheral surface and the rotation center of the rotor is the minimum to the maximum angle position on the downstream side of the first angular position in the rotation direction of the rotor. The angle to the second angle position is θ1,
The angle from the first angle position to the third angle position located at the most upstream of the angle positions where the distance is the minimum on the downstream side of the second angle position in the rotation direction is θ2.
When defined, it is configured to satisfy θ _{1 <θ 2/2.}

(2) The vane pump according to at least one embodiment of the present invention is
The pump casing that forms the pump chamber and
A rotor placed in the pump chamber and having multiple slits on the outer peripheral surface,
With multiple vanes, each placed in multiple slits,
The pump chamber includes an inner peripheral surface formed so that the distance from the center of rotation of the rotor changes in the circumferential direction of the rotor.
In the protrusion amount change curve showing the relationship between the phase of the rotor in the rotation direction of the rotor and the protrusion amount of the first vane among the plurality of vanes protruding from the outer peripheral surface of the rotor.
The phase of the rotor that maximizes the amount of protrusion of the first vane is the first phase, the phase of the rotor that minimizes the amount of protrusion of the first vane next to the first phase is the second phase, and the phase of the first vane in the first phase The protrusion amount is Amax, the protrusion amount of the first vane in the second phase is Amin, and the phase of the rotor whose protrusion amount is half of (Amax-Amin) between the first phase and the second phase is the third phase. When the phase of the midpoint between the 1st phase and the 2nd phase is defined as the 4th phase,
The third phase is located between the first phase and the fourth phase.

(3) In some embodiments, in the vane pump according to (1) above.
In the protrusion amount change curve showing the relationship between the phase of the rotor in the rotation direction of the rotor and the protrusion amount of the first vane among the plurality of vanes protruding from the outer peripheral surface of the rotor.
The phase of the rotor that maximizes the amount of protrusion of the first vane is the first phase, the phase of the rotor that minimizes the amount of protrusion of the first vane next to the first phase is the second phase, and the phase of the first vane in the first phase The protrusion amount is Amax, the protrusion amount of the first vane in the second phase is Amin, and the phase of the rotor whose protrusion amount is half of (Amax-Amin) between the first phase and the second phase is the third phase. When the phase of the midpoint between the 1st phase and the 2nd phase is defined as the 4th phase,
The third phase may be located between the first phase and the fourth phase.

(4) In some embodiments, in the vane pump according to (2) or (3) above.
The vane velocity change line showing the relationship between the rotor phase in the rotation direction of the rotor and the velocity of the first vane in the protruding direction of the first vane is the velocity between the first phase and the second phase as the phase advances. Including the first section where
In the first section, the slope of the velocity may become smaller as the phase advances.

(5) In some embodiments, in the vane pump according to (4) above.
In the first section, the slope of the velocity may gradually decrease as the phase advances.

(6) In some embodiments, in the vane pump according to any one of (1) to (5) above.
The pressure in the first space defined by two adjacent vanes in the pump chamber may be increased to atmospheric pressure or higher, and then the first space and the exhaust port of the pump chamber may communicate with each other.

(7) In some embodiments, in the vane pump according to any one of (1) to (6) above.
The inner peripheral surface of the pump chamber is
The distance between the inner peripheral surface and the rotation center of the rotor may be configured to have a maximum value at two angular positions symmetrical with respect to the rotation center.

(8) In some embodiments, in the vane pump according to any one of (1) to (6) above.
The inner peripheral surface of the pump chamber is
The distance between the inner peripheral surface and the rotation center of the rotor may be configured to have a maximum value at three angular positions that are evenly spaced in the circumferential direction of the rotor.

(9) In some embodiments, in the vane pump according to any one of (1) to (8) above.
The inner peripheral surface of the pump chamber is
In the volume change curve representing the relationship between the phase of the rotor in the rotation direction of the rotor and the volume of the first space defined by two adjacent vanes in the pump chamber, the phase of the rotor corresponding to the minimum value of the volume is set as the first. 5 phases, the phase closest to the 5th phase among the phases corresponding to the turning points of the volume change curve in the section where the volume decreases is the 6th phase, the angle from the 5th to the 6th phases is α1, and the volume change curve When the angle corresponding to one cycle is α2, α1 / α2 <3/4 may be satisfied.

According to at least one embodiment of the present disclosure, it is possible to provide a vane pump capable of improving pump efficiency.

It is a schematic exploded perspective view which shows the vane pump 2 which concerns on one Embodiment. It is a partially cutaway sectional view of the vane pump 2 shown in FIG. It is a figure which looked at the pump cover 18 from above. It is a top view which shows the structural example of the pump chamber 5 in one Embodiment. It is a figure which illustrates the shape of the inner peripheral surface 42 in one Embodiment. It is a figure which illustrates the volume change of the 1st space S1 in the vane pump 2 which concerns on one Embodiment. It is the schematic which shows the structural example of the pump chamber 5 which concerns on one Embodiment. It is a graph which shows an example of the vane acceleration change line F1 which shows the relationship between the phase of a rotor 38 and the acceleration of a vane 40 in the rotation direction Rd of a rotor 38. It is a graph which shows an example of the vane velocity change line F2 which shows the relationship between the phase of a rotor 38 and the moving velocity of a vane 40. It is a graph which shows an example of the vane protrusion amount change curve F3 which shows the relationship between the phase of a rotor 38, and the protrusion amount A of vane 40. It is a graph which shows an example of the volume change curve F4 which shows the relationship between the phase of a rotor 38, and the volume V of the first space S1. It is a perspective view which schematically exemplifies the vane pump which concerns on another embodiment.

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 the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. Absent.
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the state of existence.
For example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or chamfering within a range where the same effect can be obtained. The shape including the part and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

First, a schematic configuration of a vane pump according to an embodiment of the present disclosure will be described. FIG. 1 is a schematic exploded perspective view showing a vane pump 2 according to an embodiment. FIG. 2 is a partially cutaway sectional view of the vane pump 2 shown in FIG. FIG. 3 is a view of the pump cover 18 as viewed from above. FIG. 4 is a plan view showing a configuration example of the pump chamber 5 in one embodiment. The illustrated vane pump 2 is an electric vacuum pump for making a negative pressure chamber of a brake booster (master back) in a vehicle such as an automobile. In the following, "upper" and "lower" mean "upper" and "lower" when the vane pump 2 is installed in the vehicle.

As shown in FIGS. 1 and 2, the vane pump 2 includes a pump casing 10 forming a pump chamber 5, a rotor 38 arranged in the pump chamber 5 and having a plurality of slits 36 formed on an outer peripheral surface 32, and a plurality of rotors 38. It includes a plurality of vanes 40 arranged in the slits 36, respectively. Further, the vane pump 2 includes a motor 66 as a drive device for rotating the rotor 38.

As shown in FIGS. 1 and 2, for example, the pump casing 10 supplies gas to the pump chamber 5 in which the rotor assembly as the movable portion 4 composed of the rotor 38 and the plurality of vanes 40 is arranged, and the pump chamber 5. The intake passage 6 for guiding the gas and the exhaust passage 8 for guiding the gas from the pump chamber 5 to the outside are included. Further, as shown in FIGS. 1 to 3, the pump casing 10 includes a pump cover 18 that covers one side (upper side) of the movable portion 4, and a top cover 44 that covers the upper side of the pump cover 18. The pump casing main body 16 of the pump casing 10 includes an inner peripheral surface 42 facing the outer peripheral surface 32 of the rotor 38.

The movable portion 4 is driven by the motor 66 to suck the gas into the pump chamber 5 and discharge the gas from the pump chamber 5 to transfer the gas. The outer peripheral surface 32 of the rotor 38 in the movable portion 4 may have a circular shape in a plan view. In this way, in the vane pump 2, the rotor 38 connected to the shaft (not shown) of the motor 66 is rotated by the motor 66, so that the vane 40 is centrifuged along the slit 36 of the rotor 38, for example, as shown in FIG. By force, the vane 40 protrudes outside the radial direction D of the rotor 38 (more specifically, the vane 40 projects from the outer peripheral surface 32 of the rotor 38 along the extending direction of the slit 36 in the direction of the rotation axis of the rotor 38). The tip portion 13 of the vane 40 is configured to slide toward the inner peripheral surface 42.

As shown in FIG. 4, for example, the slit 36 may be formed linearly in a plan view so as to go inward in the radial direction D of the rotor 38 and toward the upstream side in the rotation direction Rd of the rotor 38. In this case, the vane 40 may be formed in a plate shape having a width (thickness) slidable along the inner wall of the slit 36. In the following, the axial direction of the rotor 38 in the vane pump 2 is simply referred to as "axial direction", the circumferential direction Cd of the rotor 38 is simply referred to as "circumferential direction", and the rotation direction Rd of the rotor 38 is simply referred to as "rotation direction". The radial direction D of the rotor 38 may be simply referred to as the "radial direction". Further, the "upstream side in the rotation direction Rd" means a direction opposite to the rotation direction Rd of the rotor 38, and the "downstream side in the rotation direction Rd" means a direction in which the rotation of the rotor 38 advances. To do. As shown in FIG. 1, in the vane pump 2, the rotor 38 side (the cover portion side) is the upper side and the motor 66 side is the lower side in the axial direction.

Here, the inner peripheral surface 42 of the pump chamber 5 will be described in more detail. FIG. 5 is a diagram illustrating the shape of the inner peripheral surface 42 (42A, 42B) in some embodiments. As illustrated in FIGS. 3 to 5, the pump chamber 5 is defined by an inner peripheral surface 42 and a bottom surface of the pump casing main body 16 shown in FIGS. 1 and 2 and a lower surface of the pump cover 18. The inner peripheral surface 42 functions as a cam surface that defines the protrusion amount A of the vane 40 from the outer peripheral surface 32 of the rotor 38 toward the outside of the rotor 38 in the radial direction D (specifically, the protrusion direction Pd) shown in FIG. The inner peripheral surface 42 of the pump chamber 5 is formed so that the distance L from the rotation center C of the rotor 38 periodically changes in the circumferential direction Cd of the rotor 38. Specifically, the inner peripheral surface 42 (42A, 42B) is the rotor from the first angular position P1 in the circumferential direction Cd where the distance L between the inner peripheral surface 42 and the rotation center C of the rotor 38 is the minimum (Lmin). Of the angle positions where the distance L is the maximum (Lmax) on the downstream side of the first angle position P1 in the rotation direction Rd of 38, the angle to the second angle position P2 located at the most upstream is θ ₁ , and the first angle position P1 Therefore, when the angle from the angle position where the distance L is the minimum (Lmin) on the downstream side of the second angle position P2 in the rotation direction Rd to the third angle position P3 located at the most upstream is defined as θ ₂ . meet the θ ₁ <θ _2/2.

That is, the inner peripheral surface 42 is upstream of the rotation direction Rd of the rotor 38 from the angle position corresponding to half of the angle θ ₂ from the first angle position P1 to the third angle position P3 where the distance L is the minimum value Lmin. The second angle position P2 having the maximum value Lmax at the distance L is located on the side. That is, the second angle position P2 at which the distance L from the rotation center C of the rotor 38 is maximum is closest to the upstream side and the downstream side from the second angle position P2 in the rotation direction Rd of the rotor 38, respectively. It is located upstream of the midpoint between the minimum first angle position P1 and the third angle position P3 in the rotation direction Rd. For example, as illustrated in FIGS. 3 to 5, in the case of the vane pump 2 in which the intake process and the exhaust process are performed twice (two cycles) for each rotation of the rotor 38, θ ₂ = 180 ° and θ ₁ <90. °. The maximum value Lmax may be a maximum value that is the maximum value compared with the distance L in the vicinity of the front and rear in the rotation direction Rd. Similarly, the minimum value Lmin may be a minimum value which is the minimum value compared with the distance L in the vicinity of the front and rear in the rotation direction Rd. Further, the maximum value Lmax may be the same value or the minimum value Lmin may be the same value over the entire circumference of the circumferential direction Cd.

Here, a change in the volume V of the first space S1 between two adjacent vanes 40 in the circumferential direction Cd of the rotor 38 in the pump chamber 5 will be described. FIG. 6 is a diagram illustrating a change in the volume V of the first space S1 in the vane pump 2 according to some embodiments. FIG. 7 is a schematic view showing a configuration example of the pump chamber 5 according to the embodiment.
In the pump chamber 5, for example, as illustrated in FIG. 4, the intake passage 6 shown in FIGS. 2 and 3 communicates between the first angle position P1 and the second angle position P2, and the second angle position The exhaust passage 8 communicates between P2 and the third angle position P3. The volume V in the first space S1 of the pump chamber 5 changes according to the protrusion amount A of the two adjacent vanes 40. The protrusion amount A of the vane 40 in the present disclosure is, for example, the distance from the outer peripheral surface 32 of the rotor 38 in FIG. 4 to the tip end (radial outer end) of the vane 40 along the extending direction of the slit 36.
Specifically, the volume V of the first space S1 changes periodically as shown in FIG. 6, and becomes the minimum when the two vanes 40 are at positions sandwiching an angular position where the distance L is the minimum. It becomes maximum when the two vanes 40 are located at positions sandwiching an angular position where the distance L is maximum. Therefore, the vane pump 2 takes in air when the distance L increases from the minimum to the maximum as the rotor 38 rotates, and exhausts the vane pump 2 when the volume decreases from the maximum to the minimum as illustrated in FIG. To do. From the viewpoint of preventing backflow from the exhaust passage 8 to the pump chamber 5, when exhausting, the fluid in the pump chamber 5 is compressed (boosted) above the pressure of the exhaust passage 8 (exhaust outlet) before exhausting to the pump chamber 5. It is preferable to exhaust it to the outside.

In this respect, according to the vane pump 2 of the present disclosure described above, by satisfying the above expression (1), in the angular position of the more upstream side than the conventional vane pump (e.g. a vane pump that satisfies theta _{1 =} theta _2/2) Since the process can be shifted to the compression process, the compression process can be lengthened. Therefore, the pressure in the first space S1 when the inside of the pump chamber 5 and the exhaust passage 8 communicate with each other and the exhaust is started can be made higher than the conventional one. This makes it possible to provide the vane pump 2 capable of effectively suppressing the backflow of the fluid from the exhaust passage 8 into the pump chamber 5 to improve the pump efficiency.

Further, by improving the pump efficiency, it is possible to save energy (reduce power consumption). Further, since the load torque is reduced, for example, when a motor having the same performance as the conventional one is used, the rotation speed is increased and the time required for exhaust can be shortened, so that the vacuum performance is improved. Further, since the amount of heat generated by the vane pump 2 is reduced by reducing the load torque, the change in the clearance inside the vane pump 2 due to thermal expansion is reduced, and the temperature characteristic of the vacuum performance is improved.

Further, by reducing the amount of heat generated by the vane pump 2, for example, the amount of wear of the rotor 38, the vane 40 and the pump casing 10 can be reduced, and the life of the pump portion can be improved. Further, the life of the motor 66 can be improved by reducing the load torque and the calorific value of the vane pump 2. Further, since the temperature of the entire product is lowered during the operation of the vane pump 2, a material having low heat resistance can be adopted. Further, since the volume change in the first space S1 can be largely secured, the number of vanes 40 provided in one rotor 38 can be reduced, for example.

In some embodiments, for example, as illustrated in FIGS. 3 to 5, the inner peripheral surfaces 42 (42A, 42B) of the pump chamber 5 have a distance L between the inner peripheral surface 42 and the rotation center C of the rotor 38. , The maximum value Lmax is set at two angular positions symmetrical with respect to the rotation center C. In this case, the two second angular positions P2 and P4 may be arranged at positions symmetrical with respect to the center of rotation C in the direction of the rotation axis of the rotor 38. Further, in this case, for example, in FIGS. 4 and 5, the angle position P3 is the first angle position in relation to the second angle position P4, and the angle position P1 is the third angle position in relation to the second angle position P4. Is.

As described above, in the configuration in which the distance L has the maximum value Lmax at two angular positions symmetrical with respect to the rotation center C, for example, one exhaust passage 8 and one intake passage 6 are provided, and one of the rotor 38 is provided. The compression process tends to be shorter than that of a vane pump in which the intake process and the exhaust process are performed once (one cycle) for each rotation (a configuration in which the maximum value Lmax is obtained only at one angle position at a distance L). Even in such a configuration in which the compression step tends to be shortened, by configuring the vane pump 2 so as to satisfy the above equation (1), the compression step can be lengthened and the above-mentioned backflow can be suppressed.

In some embodiments, the vane pump 2 described above exhausts the first space S1 and the exhaust after the pressure in the first space S1 defined by two adjacent vanes 40 in the pump chamber 5 is increased to atmospheric pressure or higher. It may be configured to communicate with the port 14 (more specifically, the exhaust port 35 of the exhaust passage 8 opened in the pump chamber 5). The profile of the inner peripheral surface 42 in which the pressure in the first space S1 is increased to atmospheric pressure or higher before the first space S1 and the exhaust port 35 of the pump chamber 5 communicate with each other is arranged in the circumferential direction Cd of the rotor 38. It can be set by conducting a test in advance in consideration of the number of vanes 40 and the position where the intake passage 6 and the exhaust passage 8 and the pump chamber 5 communicate with each other in the circumferential direction Cd.

In the vane pump 2 for making the negative pressure chamber of the brake booster in the vehicle negative pressure, the exhaust port 14 is open to the atmosphere, and the pressure in the exhaust passage 8 is often atmospheric pressure. Therefore, according to the configuration in which the pressure of the first space S1 is increased to the atmospheric pressure or higher and then the first space S1 and the exhaust port 35 of the pump chamber 5 are communicated with each other, the exhaust of the first space S1 and the pump chamber 5 is exhausted. Since the pressure in the first space S1 when the communication with the port 35 is started can be made higher than the pressure in the exhaust passage 8, the fluid from the exhaust passage 8 into the first space S1 of the pump chamber 5 The backflow can be effectively suppressed.

FIG. 8 is a graph showing an example of the vane acceleration change line F1 showing the relationship between the phase of the rotor 38 (hereinafter, simply referred to as “the phase of the rotor 38”) and the acceleration of the vane 40 in the rotation direction Rd of the rotor 38. .. FIG. 9 is a graph showing an example of the vane velocity change line F2 showing the relationship between the phase of the rotor 38 and the moving velocity of the vane 40. FIG. 10 is a graph showing an example of a vane protrusion amount change curve F3 showing the relationship between the phase of the rotor 38 and the protrusion amount A of the vane 40. FIG. 11 is a graph showing an example of the volume change curve F4 showing the relationship between the phase of the rotor 38 and the volume V of the first space S1.
In the vane pump 2 according to at least one embodiment of the present invention, for example, as illustrated in FIG. 10, in the vane protrusion amount change curve F3, the phase of the rotor 38 in which the protrusion amount A of the first vane 40 is maximized is set to the first phase. The phase of the rotor 38 that minimizes the protrusion amount A of the first vane 40 next to the phase Ph1 and the first phase Ph1 is the second phase Ph2, the protrusion amount A of the first vane 40 in the first phase Ph1 is Amax, and the second The protrusion amount A of the first vane 40 in the phase Ph2 is Amin, and the phase of the rotor 38 in which the protrusion amount A is half of (Amax-Amin) between the first phase Ph1 and the second phase Ph2 is the third phase Ph3. When the phase of the midpoint H between the first phase Ph1 and the second phase Ph2 is defined as the fourth phase Ph4, the third phase Ph3 is located between the first phase Ph1 and the fourth phase Ph4.
That is, as shown in FIG. 10, the vane protrusion amount change curve F3 is a graph in which the protrusion side and the return side are asymmetric with respect to the phase of the rotor 38 in which the protrusion amount A of the first vane 40 is the maximum or the minimum. Become. The inner peripheral surface 42 that defines the protrusion amount A of the vane 40 so that the vane protrusion amount change curve F3 satisfies the above-mentioned feature of FIG. 10 has a shape like the inner peripheral surface 42A shown in FIG. 5 in a plan view. Is.

According to the vane pump 2 having such a configuration, the amount of compression (first space S1) in the compression step, that is, the step in which the volume V of the first space S1 is reduced, as compared with the case where the third phase Ph3 is located in the fourth phase Ph4 or later, for example. The pressure in the first space S1 at the time of starting the exhaust can be increased by increasing the amount of decrease in the volume V of the above. That is, in the configuration that satisfies θ _{1 <θ 2/2} as described above, by advancing the timing of transition to the compression step than in the case of θ1 = θ2 / 2, the first space S1 in the time of exhaust gas is started While it is possible to increase the pressure more than before, in the configuration where the third phase Ph3 is located between the first phase Ph1 and the fourth phase Ph4, the first half of the entire volume V reduction step (compression step). By ensuring a larger amount of compression in the latter half than in the latter half, the pressure in the first space S1 when exhaust is started can be increased as compared with the conventional case. Thereby, it is possible to provide the vane pump 2 capable of effectively suppressing the backflow of the fluid from the exhaust passage 8 into the pump chamber 5 and improving the pump efficiency.

In some embodiments, in the vane pump 2 where the third phase Ph3 is located between the first phase Ph1 and the fourth phase Ph4, as illustrated in FIG. 9, the vane velocity change line F2 advances in phase. A first section Z1 in which the speed of the first vane 40 increases as the speed increases is included between the first phase Ph1 and the second phase Ph2. In the first section Z1, the slope of the velocity (that is, the acceleration illustrated in FIG. 8) becomes smaller as the phase advances.

According to the vane pump 2 having such a configuration, the volume change on the compression start side can be made larger than the volume change on the compression end side in the compression step, that is, the stroke on the exhaust side where the volume in the first space S1 decreases. .. That is, in the compression step in the vane protrusion amount change curve F3, the pressure in the first space S1 at the start of exhaust is increased by making the volume change on the compression start side larger than the volume change on the compression end side. can do.

In some embodiments, for example, as illustrated in FIG. 9, in the first section Z1 of the vane velocity change line F2, the velocity gradient may gradually decrease as the phase advances. For example, in the example shown in FIG. 9, in the first section Z1, the slope of the velocity of the vane 40 decreases in two steps as the phase advances. The change in the velocity inclination (acceleration) of the vane 40 on the exhaust side may be three or more steps. Further, in another embodiment, the vane velocity change line F2 may continuously decrease the slope of the velocity of the vane 40 as the phase advances in the first section Z1.

According to the vane pump 2 having such a configuration, the volume change on the compression start side can be made larger than the volume change on the compression end side in the compression step, that is, the stroke on the exhaust side where the volume in the first space S1 decreases. .. That is, in the compression step in the vane protrusion amount change curve F3, the pressure in the first space S1 at the start of exhaust is increased by making the volume change on the compression start side larger than the volume change on the compression end side. can do.

In some embodiments, for example, as illustrated in FIG. 11, in the volume change curve F4, the phase of the rotor 38 corresponding to the minimum value of the volume V is set to the fifth phase Ph5, and the volume change curve in the section where the volume V decreases. Of the phases corresponding to the turning point I of F4, the phase located next to the fifth phase Ph5 is the sixth phase Ph6, the angle from the fifth phase Ph5 to the sixth phase Ph6 is α1, and one cycle of the volume change curve F4. When the angle corresponding to is α2, the inner peripheral surface 42A of the pump chamber 5 is configured to satisfy α1 / α2 <3/4.

According to the vane pump 2 having such a configuration, the volume change on the compression start side can be made larger than the volume change on the compression end side in the compression step, that is, on the exhaust side where the volume in the first space S1 decreases. That is, in the compression step on the volume change curve F4, the pressure in the first space S1 at the start of exhaust is increased by making the volume change on the compression start side larger than the volume change on the compression end side. Can be done.

FIG. 12 is a perspective view schematically illustrating a vane pump according to another embodiment.
In some embodiments, for example, as illustrated in FIG. 12, in the vane pump 2 according to any one of the above embodiments, the inner peripheral surface 42 of the pump chamber 5 is the rotation of the inner peripheral surface 42 and the rotor 38. The distance L from the center C may be configured to have a maximum value Lmax at three angular positions P2, P4, and P6 that are equidistant to the circumferential direction Cd of the rotor 38. In this case, the inner peripheral surface 42 is configured such that the distance L becomes the minimum value Lmin at the three angular positions P1, P3, and P5 that are equidistant to the circumferential direction Cd of the rotor 38. In this way, in the vane pump 2 in which the intake process and the exhaust process are performed three times (three cycles) for each rotation of the rotor 38, the inner peripheral surface 42 satisfies θ ₂ = 120 ° and θ ₁ <60 °. May be formed.

According to the vane pump 2 having such a configuration, the above-described benefits of the present disclosure can be enjoyed even in the vane pump 2 in which the intake process and the exhaust process are performed three times (three cycles) for each rotation of the rotor 38. Further, in another embodiment, the vane pump may be configured such that the intake process and the exhaust process are performed four times (4 cycles) or more for each rotation of the rotor.

According to at least one embodiment of the present disclosure, it is possible to provide a vane pump 2 capable of improving pump efficiency.

The present invention is not limited to the above-described embodiment, and includes a modified form of the above-described embodiment and a combination of these embodiments. For example, in some of the above-described embodiments, as a plurality of slits 36 and a plurality of vanes 40, six slits 36 arranged at equal intervals in the circumferential direction Cd of the rotor 38 and six slits 36 arranged in each slit 36, respectively. Although the configuration including one vane 40 is illustrated, the number of slits 36 and vanes 40 is not limited to 6, and may be, for example, 2 to 5 or 7 or more.

2 vane pump 5 pump chamber 14 exhaust port 32 outer peripheral surface 35 exhaust port 36 slit 38 rotor 40 vane 42 inner peripheral surface S1 first space F1 vane acceleration change line F2 vane speed change line F3 protrusion amount change curve F4 volume change curve P1 first Angle position P2 Second angle position P3 Third angle position Ph1 First phase Ph2 Second phase Ph3 Third phase Ph4 Fourth phase Z1 First section A 1st vane protrusion amount Amax 1st vane maximum protrusion amount Amin 1st Minimum protrusion amount of vane C Rotation center Cd Circumferential direction I Curved point L Distance between the inner peripheral surface of the pump chamber and the rotation center of the rotor Pd Projection direction of vane Rd Rotation direction

Claims (9)

The pump casing that forms the pump chamber and
A rotor arranged in the pump chamber and having a plurality of slits formed on the outer peripheral surface,
With a plurality of vanes arranged in the plurality of slits, respectively,
The pump chamber is defined by an inner peripheral surface formed so that the distance from the rotation center of the rotor changes in the circumferential direction of the rotor.
The inner peripheral surface of the pump chamber is
The distance is maximum from the first angle position in the circumferential direction where the distance between the inner peripheral surface and the rotation center of the rotor is the minimum to the downstream side of the first angle position in the rotation direction of the rotor. The angle to the second angular position, which is the most upstream of the angular positions, is θ ₁ ,
The angle from the first angle position to the third angle position located at the most upstream of the angle positions where the distance is the minimum on the downstream side of the second angle position in the rotation direction is θ ₂ .
Vane pump is defined to the, and is configured to satisfy θ _{1 <θ 2/2} and. The pump casing that forms the pump chamber and
A rotor arranged in the pump chamber and having a plurality of slits formed on the outer peripheral surface,
With a plurality of vanes arranged in the plurality of slits, respectively,
The pump chamber is defined by an inner peripheral surface formed so that the distance from the rotation center of the rotor changes in the circumferential direction of the rotor.
In the protrusion amount change curve showing the relationship between the phase of the rotor in the rotation direction of the rotor and the protrusion amount of the first vane among the plurality of vanes protruding from the outer peripheral surface of the rotor.
The phase of the rotor that maximizes the protrusion amount of the first vane is the first phase, and the phase of the rotor that minimizes the protrusion amount of the first vane next to the first phase is the second phase. The protrusion amount of the first vane in the first phase is Amax, the protrusion amount of the first vane in the second phase is Amin, and the protrusion amount between the first phase and the second phase is (Amax). When the phase of the rotor, which is half of −Amin), is defined as the third phase, and the phase at the midpoint between the first phase and the second phase is defined as the fourth phase,
The third phase is a vane pump located between the first phase and the fourth phase. In the protrusion amount change curve showing the relationship between the phase of the rotor in the rotation direction of the rotor and the protrusion amount of the first vane among the plurality of vanes protruding from the outer peripheral surface of the rotor.
The phase of the rotor that maximizes the protrusion amount of the first vane is the first phase, and the phase of the rotor that minimizes the protrusion amount of the first vane next to the first phase is the second phase. The protrusion amount of the first vane in the first phase is Amax, the protrusion amount of the first vane in the second phase is Amin, and the protrusion amount between the first phase and the second phase is (Amax). When the phase of the rotor, which is half of −Amin), is defined as the third phase, and the phase at the midpoint between the first phase and the second phase is defined as the fourth phase,
The vane pump according to claim 1, wherein the third phase is located between the first phase and the fourth phase. A vane velocity change line indicating the relationship between the phase of the rotor in the rotation direction of the rotor and the velocity of the first vane in the protruding direction of the first vane is formed between the first phase and the second phase. Includes a first section in which the velocity increases as the phase advances.
The vane pump according to claim 2 or 3, wherein in the first section, the slope of the velocity decreases as the phase advances. The vane pump according to claim 4, wherein in the first section, the slope of the velocity gradually decreases as the phase advances. The pressure in the first space defined by the two adjacent vanes in the pump chamber is increased to atmospheric pressure or higher, and then the first space and the exhaust port of the pump chamber communicate with each other. ,
The vane pump according to any one of claims 1 to 5. The inner peripheral surface of the pump chamber is
Any one of claims 1 to 6 configured such that the distance between the inner peripheral surface and the rotation center of the rotor has a maximum value at two angular positions symmetrical with respect to the rotation center. Vane pump described in. The inner peripheral surface of the pump chamber is
Any of claims 1 to 6 configured such that the distance between the inner peripheral surface and the rotation center of the rotor has a maximum value at three angular positions at equal intervals in the circumferential direction of the rotor. The vane pump described in item 1. The inner peripheral surface of the pump chamber is
Corresponds to the minimum value of the volume in the volume change curve representing the relationship between the phase of the rotor in the rotation direction of the rotor and the volume of the first space defined by the two adjacent vanes in the pump chamber. The phase of the rotor is the fifth phase, and the phase located next to the fifth phase among the phases corresponding to the turning points of the volume change curve in the section where the volume is decreasing is the sixth phase and the fifth phase. Any of claims 1 to 8 configured to satisfy α1 / α2 <3/4 when the angle to the sixth phase is α1 and the angle corresponding to one cycle of the volume change curve is α2. The vane pump described in item 1.