JP6784543B2 - Vane pump - Google Patents

Description

The present invention relates to a vane pump.

Patent Document 1 discloses a vane pump including a rotor driven to rotate, a plurality of vanes slidably inserted into a plurality of slits formed in the rotor, and a rotor and a cam ring accommodating the vanes. .. The vane is urged in a direction protruding from the slit as the rotor rotates, and the tip of the vane slides into contact with the inner peripheral surface (inner peripheral cam surface) of the cam ring. Inside the cam ring, a plurality of pump chambers are formed by the outer peripheral surface of the rotor, the inner peripheral cam surface, and adjacent vanes.

In the vane pump disclosed in Patent Document 1, the vane that is in sliding contact with the inner peripheral cam surface reciprocates as the rotor rotates. The pump chamber repeats expansion and contraction as the vane reciprocates. The working fluid is sucked into the pump chamber through the suction port in the suction region where the pump chamber expands. The working fluid in the pump chamber is discharged from the discharge port in the discharge region where the pump chamber contracts.

Japanese Unexamined Patent Publication No. 2014-74368

The vane is pushed most into the slit of the rotor as it moves from the discharge area to the suction area, at which time the volume of the pump chamber is minimized. The working fluid of the minimum capacity of the pump chamber is not discharged from the discharge port while the pump chamber passes through the discharge region, and remains in the pump chamber.

Further, the pressure of the working fluid in the pump chamber increases with the contraction of the pump chamber, and becomes the highest when the pump chamber moves from the discharge region to the suction region. As the pump chamber moves within the suction region, the pump chamber expands and the pressure of the working fluid remaining in the pump chamber gradually decreases. When the pump chamber reaches the suction port while the pressure in the pump chamber is low, the working fluid begins to be sucked into the pump chamber from the suction port.

However, the pressure of the working fluid that remains in the pump chamber without being discharged from the discharge port may not decrease due to the inertia and compressibility of the working fluid even if the pump chamber moves within the suction region. If the pressure does not drop by the time the pump chamber reaches the suction port, the working fluid remaining in the pump chamber may be discharged from the suction port.

When a flow in the discharge direction is formed at the suction port, it takes time for the flow in the suction direction to be formed due to the inertia of the working fluid. Therefore, the amount of the working fluid sucked from the suction port into the pump chamber is reduced, and the suction characteristics of the vane pump are lowered.

An object of the present invention is to improve the suction characteristics of a vane pump.

The first invention is formed in at least one of a rotor, a plurality of vanes, a cam ring, first and second side members, a pump chamber, a cam ring, a first side member and a second side member, and a pump chamber. The first and second suction ports for guiding the working fluid are provided, and the starting end of the second suction port is formed in front of the starting end of the first suction port in the rotational direction.

In the first invention, since the start end of the second suction port is formed ahead of the start end of the first suction port in the rotational direction, the pump chamber reaches the first suction port before reaching the second suction port. Therefore, even if the pump chamber reaches the first suction port without reducing the pressure of the working fluid remaining in the pump chamber without being discharged from the discharge port in the contraction region, the working fluid in the pump chamber is only from the first suction port. It is discharged, and a flow in the discharge direction is not formed at the second suction port. When the pump chamber reaches the second suction port, a flow in the suction direction is immediately formed at the second suction port.

The second invention comprises a first suction port including a first side port formed by a first side member and a cam ring, and a second side port formed by a second side member and a cam ring. 2 The suction port is a center port formed by a hole penetrating between the outer peripheral surface and the inner peripheral cam surface of the cam ring.

In the second invention, since the start end of the center port is formed ahead of the start ends of the first and second side ports in the rotation direction, when the pump chamber reaches the center port, the suction direction is immediately reached at the center port. Flow is formed. Therefore, the working fluid can be distributed to the central portion of the pump chamber, and the suction characteristics of the vane pump can be further improved.

The third invention further includes a low pressure chamber communicating with the pump chamber through each of the first side port and the second side port, and the resistance of the first passage from the low pressure chamber to the pump chamber through the first side port and the low pressure chamber. The resistance of the second passage from the second side port to the pump chamber is equal, and the center port is characterized by being formed in the center of the cam ring in the axial direction.

In the third invention, since the center port is formed at the center of the cam ring in the axial direction, the working fluid is distributed to the central portion of the pump chamber. Therefore, the suction characteristics of the vane pump can be improved more reliably.

The fourth invention further includes a low pressure chamber communicating with the pump chamber through each of the first side port and the second side port, and the resistance of the first passage from the low pressure chamber to the pump chamber through the first side port is a low pressure chamber. The center port is characterized in that it is biased toward the first side port, which is larger than the resistance of the second passage from the second side port to the pump chamber.

In the fourth invention, since the center port is formed biased to the first side port, the working fluid is distributed to the portion biased to the first side port in the pump chamber. Therefore, the suction characteristics of the vane pump can be improved more reliably.

In the fifth invention, the start end of the first suction port and the start end of the second suction port are separated from each other by a predetermined angle about the rotation axis of the rotor, and the pump chamber is the first suction port at a predetermined angle. It is characterized by the angle at which the rotor rotates from the time when the start end of the pump chamber is reached until the pressure in the pump chamber drops.

In the fifth invention, the start end of the first suction port and the start end of the second suction port are separated from each other by the above-mentioned predetermined angle about the rotation axis of the rotor. Therefore, when the pump chamber reaches the second suction port, the pressure in the pump chamber drops sufficiently. Therefore, it is possible to more reliably prevent the formation of a flow in the discharge direction at the second suction port, and it is possible to more reliably improve the suction characteristics of the vane pump.

The sixth invention is characterized in that, when the above-mentioned predetermined angle is θ, the predetermined angle is within the range obtained by the following equation.

0 <θ [deg] ≤7α + 10
However, α: The ratio of the minimum volume of the pump chamber to the maximum volume of the pump chamber

In the sixth invention, since the predetermined angle θ is larger than 0 (zero), the pressure in the pump chamber drops when the pump chamber reaches the second suction port. Therefore, it is possible to prevent a flow in the discharge direction from being formed in the second suction port, and it is possible to improve the suction characteristics of the vane pump. Further, since the predetermined angle θ is equal to or less than the angle obtained by 7α + 10, the start end of the second suction port is forward of the start end of the first suction port in the rotation direction beyond the expected delay of the pressure drop. Not formed. Therefore, it is possible to prevent the second suction port from becoming too small and the amount of the working fluid sucked from the second suction port into the pump chamber to decrease, and the suction characteristics of the vane pump can be improved more reliably.

According to the present invention, the suction characteristics of the vane pump can be improved.

It is sectional drawing of the vane pump which concerns on 1st Embodiment of this invention. It is a front view of a rotor, a vane and a cam ring, and shows the state which assembled the rotor, a vane and a cam ring. It is a front view of the 1st side plate. It is a front view of the 2nd side plate. It is a side view of a cam ring, a 1st side plate and a 2nd side plate, and shows the state which the 1st side plate and the 2nd side plate are assembled to a cam ring. It is a rear view of a cam ring. It is a front view of a rotor, a vane and a cam ring, and shows the state which the 1st side plate is assembled to the cam ring. It is a graph which shows the relationship between the ratio of the minimum volume of a pump chamber, and the delay of a pressure drop. It is sectional drawing of the vane pump which concerns on 2nd Embodiment of this invention. It is a side view of a cam ring, a 1st side plate and a 2nd side plate, and shows the state which the 1st side plate and the 2nd side plate are assembled to a cam ring.

Hereinafter, the vane pumps 100 and 200 according to the embodiment of the present invention will be described with reference to the drawings. The vane pumps 100 and 200 are used as a hydraulic supply source for a hydraulic device 1 (for example, a power steering device, a transmission, etc.) mounted on a vehicle. Here, the vane pumps 100 and 200 in which hydraulic oil is used as the hydraulic fluid will be described, but other fluids such as hydraulic water may be used as the hydraulic fluid.

<First Embodiment>
First, the vane pump 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 7. The vane pump 100 includes a drive shaft 10, a rotor 20 connected to the drive shaft 10, a plurality of vanes 30 provided on the rotor 20, and a cam ring 40 accommodating the rotor 20 and the vanes 30.

The drive shaft 10 is rotatably supported by the pump body 50 and the pump cover 60. When the power of the engine or an electric motor (not shown) is transmitted to the drive shaft 10, the rotor 20 rotates with the rotational drive of the drive shaft 10.

In the following, the direction along the rotation axis of the rotor 20 is referred to as "axial direction", the radial direction centered on the rotation axis of the rotor 20 is referred to as "diameter direction", and the direction in which the rotor 20 rotates during normal operation of the vane pump 100. Is referred to as "rotational direction".

The vane pump 100 further includes a first side member arranged so as to sandwich the rotor 20 and the cam ring 40 in the axial direction, and a first side plate 70 and a second side plate 80 as the second side member. The first side plate 70 and the second side plate 80 have a side surface 70a and a side surface 80a that abut the rotor 20 and the cam ring 40, respectively. The pump chamber 41 is defined by the rotor 20, the cam ring 40, the adjacent vanes 30, the first side plate 70 and the second side plate 80.

FIG. 2 is a front view of the rotor 20, vane 30, and cam ring 40 assembled and viewed from the side of the pump cover 60. As shown in FIG. 2, a plurality of slits 22 having openings 21 on the outer peripheral surface are formed radially at predetermined intervals in the rotor 20. The opening 21 of the slit 22 is formed in a raised portion 23 that rises radially outward from the outer circumference of the rotor 20. That is, as many raised portions 23 as the number of slits 22 are formed on the outer circumference of the rotor 20.

The vane 30 is slidably inserted into each slit 22. The tip 31 of the vane 30 faces the inner peripheral surface 40a of the cam ring 40. The base end portion 32 of the vane 30 is located in the slit 22, and the back pressure chamber 24 is formed by the slit 22 and the vane 30.

When the rotor 20 rotates, centrifugal force is generated in the vane 30. By this centrifugal force, the vane 30 is pressed in the direction of protruding from the slit 22. In the pressed state, the vane 30 protrudes from the slit 22, and the tip portion 31 of the vane 30 comes into contact with the inner peripheral surface 40a of the cam ring 40.

The inner peripheral surface 40a of the cam ring 40 is formed in a substantially oval shape. Hereinafter, the inner peripheral surface 40a is also referred to as an “inner peripheral cam surface 40a”.

Since the inner peripheral cam surface 40a is formed in a substantially oval shape, the vane 30 reciprocates in the radial direction with respect to the rotor 20 as the rotor 20 rotates. As the vane 30 reciprocates, the pump chamber 41 repeats expansion and contraction.

In the vane pump 100, the vane 30 reciprocates twice while the rotor 20 makes one rotation, and the pump chamber 41 repeats expansion and contraction twice. That is, the vane pump 100 alternately has two expansion regions 42a and 42c in which the pump chamber 41 expands and two contraction regions 42b and 42d in which the pump chamber 41 contracts in the rotational direction.

See FIG. 1 again. The pump body 50 is formed with a housing recess 51 that houses the rotor 20, the cam ring 40, and the first side plate 70. The first side plate 70 is arranged on the bottom surface 51a of the accommodating recess 51.

An annular groove 52 is formed on the bottom surface 51a of the accommodating recess 51. The annular groove 52 and the first side plate 70 form a high-pressure chamber 53 into which the hydraulic oil discharged from the pump chamber 41 flows. The high pressure chamber 53 is connected to the hydraulic equipment 1, and the hydraulic oil discharged from the pump chamber 41 is supplied to the hydraulic equipment 1 through the high pressure chamber 53.

FIG. 3 is a front view of the first side plate 70 as viewed from the side of the cam ring 40. As shown in FIGS. 1 and 3, the first side plate 70 is formed in an annular shape having holes 71. The drive shaft 10 is inserted through the hole 71.

The first side plate 70 is provided with two discharge ports 72 for guiding the hydraulic oil discharged from the pump chamber 41 to the high pressure chamber 53. The discharge port 72 is located in each of the contraction regions 42b and 42d.

The pump chamber 41 contracts while the pump chamber 41 (see FIG. 2) passes through the contraction regions 42b, 42d. As the pump chamber 41 contracts, the pressure in the pump chamber 41 rises, and the hydraulic oil in the pump chamber 41 is discharged from the discharge port 72. That is, the hydraulic oil in the pump chamber 41 is discharged from the discharge port 72 while the pump chamber 41 passes through the contraction regions 42b and 42d. Since the hydraulic oil is discharged in the contraction regions 42b and 42d in this way, the contraction regions 42b and 42d are also referred to as "discharge regions".

The vane 30 is pushed most into the slit 22 when moving from the contraction region 42d to the expansion region 42a and from the contraction region 42b to the expansion region 42c, at which time the volume of the pump chamber 41 is minimized. The hydraulic oil for the minimum capacity of the pump chamber 41 is not discharged from the pump chamber 41 while the pump chamber 41 passes through the contraction regions 42d and 42b, and remains in the pump chamber 41. As described above, the minimum volume of the pump chamber 41 does not function as a pump and is also called a "dead volume".

The first side plate 70 is formed with two back pressure passages 73 for guiding hydraulic oil from the high pressure chamber 53 to the back pressure chamber 24 (see FIGS. 1 and 2). The back pressure passage 73 has an arc shape centered on the hole 71, and is located in the expansion regions 42a and 42c. Therefore, hydraulic oil is guided from the high pressure chamber 53 to the back pressure chamber 24 passing through the expansion regions 42a and 42c. The vanes 30 passing through the expansion regions 42a and 42c are pressed by the pressure in the back pressure chamber 24 in the direction of protruding from the slit 22 (see FIG. 3).

As described above, in the vane pump 100, the vane 30 is pressed in the direction of protruding from the slit 22 not only by the centrifugal force generated by the rotation of the rotor 20 but also by the pressure in the back pressure chamber 24.

See FIG. 1 again. The accommodating recess 51 of the pump body 50 is larger than the cam ring 40. A fluid chamber 54 extending from the outer circumference of the second side plate 80 to the outer circumference of the first side plate 70 is formed between the cam ring 40 and the pump body 50.

The opening of the accommodating recess 51 is sealed by the pump cover 60. The pump cover 60 is fastened to the pump body 50 by bolts (not shown). A second side plate 80 is arranged between the pump cover 60 and the cam ring 40.

FIG. 4 is a front view of the second side plate 80 as viewed from the side of the pump cover 60. As shown in FIGS. 1 and 4, the second side plate 80 is formed in an annular shape having holes 81. The drive shaft 10 is inserted into the hole 81.

As shown in FIG. 1, a low pressure chamber 61 is formed in the pump cover 60. The low pressure chamber 61 is connected to the tank 2. When the vane pump 100 operates, the hydraulic oil in the tank 2 is supplied to the low pressure chamber 61. The low pressure chamber 61 communicates with the fluid chamber 54, and the hydraulic oil in the tank 2 is supplied to the fluid chamber 54 through the low pressure chamber 61.

The cam ring 40 and the second side plate 80 are provided with a second side port 82 as a second suction port for guiding the hydraulic oil in the low pressure chamber 61 to the pump chamber 41. Further, the cam ring 40 and the first side plate 70 are provided with a first side port 74 as a first suction port for guiding the hydraulic oil in the fluid chamber 54 to the pump chamber 41. The first side port 74 and the second side port 82 are located in the expansion regions 42a and 42c, respectively.

The pump chamber 41 expands while the pump chamber 41 passes through the expansion regions 42a, 42c (see FIG. 2). As the pump chamber 41 expands, the pressure inside the pump chamber 41 decreases, and hydraulic oil is sucked into the pump chamber 41 from the first side port 74 and the second side port 82. That is, the hydraulic oil is sucked into the pump chamber 41 from the first side port 74 and the second side port 82 while the pump chamber 41 passes through the expansion regions 42a and 42c. As described above, since the hydraulic oil is sucked into the pump chamber 41 in the expansion regions 42a and 42c, the expansion regions 42a and 42c are also referred to as "suction regions".

FIG. 5 is a side view of the first side plate 70 and the second side plate 80 assembled to the cam ring 40 and viewed from the outside in the radial direction. As shown in FIGS. 3 and 5, two recesses 75 are formed on the side surface 70a of the first side plate 70. The recessed portion 75 opens in the outer peripheral surface 70b of the first side plate 70.

FIG. 6 is a rear view of the cam ring 40 as viewed from the side of the first side plate 70. As shown in FIGS. 5 and 6, two notches 43 are provided on the end surface 40b of the cam ring 40 in contact with the first side plate 70. The notch 43 is located in the expansion regions 42a and 42c, and is formed from the outer peripheral surface 40d of the cam ring 40 to the inner peripheral cam surface 40a.

In the state where the first side plate 70 is assembled to the cam ring 40, the recessed portion 75 of the first side plate 70 faces the notch 43 of the cam ring 40. The hydraulic oil in the fluid chamber 54 (see FIG. 1) is guided to the pump chamber 41 through a port formed by the recess 75 and the notch 43. That is, in the vane pump 100, the first side port 74 is formed by the recess 75 of the first side plate 70 and the notch 43 of the cam ring 40.

As shown in FIGS. 4 and 5, two recesses 83 are provided on the outer peripheral surface 80b of the second side plate 80. The recessed portion 83 is formed from the side surface 80a of the second side plate 80 to the side surface 80c of the second side plate 80 opposite to the side surface 80a.

As shown in FIGS. 2 and 5, two notches 44 are provided in the end surface 40c of the cam ring 40 in contact with the second side plate 80. The notch 44 is located in the expansion regions 42a and 42c, and is formed from the outer peripheral surface 40d of the cam ring 40 to the inner peripheral cam surface 40a.

In the state where the second side plate 80 is assembled to the cam ring 40, the recessed portion 83 of the second side plate 80 faces the notch 44 of the cam ring 40. The hydraulic oil in the low pressure chamber 61 (see FIG. 1) is guided to the pump chamber 41 through a port formed by the recess 83 and the notch 44. As described above, in the vane pump 100, the second side port 82 is formed by the recessed portion 83 of the second side plate 80 and the notch 44 of the cam ring 40.

FIG. 7 is a front view of the rotor 20, the vane 30, and the cam ring 40, showing a state in which the first side plate 70 is assembled to the cam ring 40. As shown in FIGS. 5 and 7, the starting end 82a of the second side port 82 is formed ahead of the starting end 74a of the first side port 74 in the rotational direction. As shown in FIG. 5, the end 82b of the second side port 82 and the end 74b of the first side port 74 are formed at substantially the same position in the rotation direction.

The "starting end" of the second side port 82 means the end portion 82a of the end portion of the second side port 82 located rearward in the rotation direction. Further, the "termination" of the second side port 82 means an end portion 82b of the end portion of the second side port 82 located forward in the rotation direction. That is, when the vane pump 100 operates, the pump chamber 41 that has moved into the expansion regions 42a and 42c reaches the start end 82a, so that the pump chamber 41 and the second side port 82 communicate with each other. When the pump chamber 41 passes through the terminal 82b of the second side port 82, the communication between the pump chamber 41 and the second side port 82 is cut off.

Similarly, the "starting end" of the first side port 74 means the end portion 74a of the end portion of the first side port 74 located rearward in the rotational direction. The “termination” of the first side port 74 means the end portion 74b of the end portion of the first side port 74 located forward in the rotation direction.

By the way, the pump chamber 41 contracts most when moving from the contraction region 42d to the expansion region 42a and when moving from the contraction region 42b to the expansion region 42c. At this time, the pressure in the pump chamber 41 becomes the highest.

The pressure of the hydraulic oil remaining in the pump chamber 41 without being discharged from the discharge port 72 may not decrease due to the inertia and compressibility of the hydraulic oil even if the pump chamber 41 moves into the expansion regions 42a and 42c. .. When the pump chamber 41 reaches the port in this state, hydraulic oil is discharged from the port.

In the vane pump 100, since the start end 82a of the second side port 82 is formed ahead of the start end 74a of the first side port 74 in the rotational direction, the pump chamber 41 is formed in the first side port before reaching the second side port 82. Reach 74. Therefore, even if the pump chamber 41 reaches the first side port 74 while the pressure of the hydraulic oil in the pump chamber 41 is high, the hydraulic oil in the pump chamber 41 is discharged only from the first side port 74 and is discharged from the second side. No flow in the discharge direction is formed at the port 82.

When the hydraulic oil in the pump chamber 41 is discharged from the first side port 74 and the pump chamber 41 moves in the expansion regions 42a and 42c as the rotor 20 rotates and the pump chamber 41 expands, the inside of the pump chamber 41 The pressure drops. When the rotor 20 further rotates and the pump chamber 41 reaches the second side port 82, the pressure in the pump chamber 41 is reduced.

Since the flow in the discharge direction is formed in the first side port 74, it may take time for the flow in the suction direction to be formed in the first side port 74 due to the inertia of the working fluid. Since the flow in the discharge direction is not formed in the second side port 82, when the pump chamber 41 reaches the second side port 82, the flow in the suction direction is immediately formed in the second side port 82. Therefore, it is possible to prevent the amount of hydraulic oil sucked from the second side port 82 into the pump chamber 41 from decreasing, and it is possible to improve the suction characteristics of the vane pump 100.

FIG. 8 is a graph showing the relationship between the ratio α of the minimum volume of the pump chamber 41 to the maximum volume of the pump chamber 41 and the delay of the pressure drop in the pump chamber 41.

The maximum volume is the volume of the pump chamber 41 when the vane 30 is most extruded from the slit 22. When the pump chamber 41 moves from the expansion region 42a to the contraction region 42b, and when it moves from the expansion region 42c to the contraction region 42d, the vane 30 is pushed out most from the slit 22, and at this time, the volume of the pump chamber 41 is maximum. It becomes. The so-called effective volume is a value obtained by subtracting the minimum volume from the maximum volume of the pump chamber 41. The effective volume corresponds to the volume of the pump chamber 41 that functions as a pump.

The delay in the pressure drop is expressed as an angle [deg] in which the rotor 20 rotates from the time when the pump chamber 41 reaches the start end 74a of the first side port 74 until the pressure drops. It is known that due to the influence of air compressibility, the larger the amount of air contained in the hydraulic oil, the later the pressure drop and the larger the angle.

In FIG. 8, the plot shows an example of the results obtained by simulation. The straight line shows an approximate line based on a plurality of simulation results, and the approximate expression is represented by the following equation (1). In the simulation, the air content of the hydraulic oil, which is generally used in the actual machine, was used as the parameter of the air content of the hydraulic oil.

θ1 [deg] = 7α + 10 ... (1)
As shown in FIG. 8, it is sufficient that the pressure in the pump chamber 41 is further rotated by the angle θ1 obtained by the equation (1) after the pump chamber 41 reaches the start end 74a of the first side port 74. It was found by simulation that it decreased to. Further, it was found by simulation that the pressure in the pump chamber 41 hardly decreased even if the rotor 20 further rotated from the angle θ1.

In the vane pump 100, as shown in FIG. 7, the start end 74a of the first side port 74 and the start end 82a of the second side port 82 are separated from each other by a predetermined angle θ about the rotation axis of the rotor 20. The predetermined angle θ is set within the range of the following equation (2).

0 <θ [deg] ≤7α + 10 ... (2)
According to the simulation, the pressure in the pump chamber 41 starts to decrease immediately after the pump chamber 41 reaches the starting end 74a of the first side port 74. In the vane pump 100, since the predetermined angle θ is larger than 0 (zero), the pressure in the pump chamber 41 is reduced when the pump chamber 41 reaches the second side port 82. Therefore, it is possible to prevent the flow in the discharge direction from being formed in the second side port 82, and it is possible to improve the suction characteristics of the vane pump 100.

Considering the machining accuracy of the cam ring 40, the first side plate 70, and the second side plate 80, it is preferable to set a predetermined angle θ by a tolerance larger than 0 (zero). As a result, it is possible to prevent a decrease in yield and an increase in the manufacturing cost of the vane pump 100.

Further, the predetermined angle θ is equal to or less than the angle θ1 obtained by the above equation (1). As described above, even if the rotor 20 further rotates from the angle θ1, the pressure in the pump chamber 41 hardly changes. That is, it is not necessary to make the predetermined angle θ larger than the angle θ1. Since the predetermined angle θ is equal to or less than the angle θ1, the starting end 82a of the second side port 82 is not formed ahead of the starting end 82a of the first side port 74 in the rotation direction beyond the expected delay of the pressure drop. .. Therefore, it is possible to prevent the second side port 82 from becoming too small and the amount of hydraulic oil sucked from the second side port 82 into the pump chamber 41 to decrease, and the suction characteristics of the vane pump 100 can be improved more reliably. Can be done.

Even when a simulation is performed using a value of 1 to 15 times the air content of a commonly used hydraulic oil as a parameter of the air content, the vane pump 100 exhibits performance within the specification range of the product. It was derived. That is, even when the hydraulic oil contains a large amount of air, by setting the predetermined angle θ within the range of the equation (2), it is possible to prevent the flow in the discharge direction from being formed in the second side port 82. It is possible to improve the suction characteristics of the vane pump 100.

Next, the operation of the vane pump 100 will be described with reference to FIGS. 1 to 4.

When the power of the engine or an electric motor (not shown) is transmitted to the drive shaft 10, the rotor 20 rotates with the rotational drive of the drive shaft 10. The vane 30 reciprocates with respect to the rotor 20 as the rotor 20 rotates, and the pump chamber 41 repeats expansion and contraction.

The hydraulic oil in the tank 2 is guided to the pump chamber 41 passing through the expansion regions 42a and 42c through the low pressure chamber 61 and the second side port 82, or through the low pressure chamber 61, the fluid chamber 54 and the first side port 74. .. The hydraulic oil in the pump chamber 41 passing through the contraction regions 42b and 42d is discharged from the discharge port 72.

In the pump chamber 41 that moves from the contraction regions 42b and 42d to the expansion regions 42a and 42c, the hydraulic oil corresponding to the dead volume remains in a state of maintaining a high pressure. When the rotor 20 rotates in this state, the pump chamber 41 reaches the first side port 74, and the hydraulic oil remaining in the pump chamber 41 is discharged from the first side port 74. Since the pump chamber 41 does not reach the second side port 82, a flow in the discharge direction is not formed in the second side port 82.

When the rotor 20 further rotates and the pump chamber 41 reaches the second side port 82, the pressure in the pump chamber 41 is reduced. Since the flow in the discharge direction is not formed in the second side port 82, when the pump chamber 41 reaches the second side port 82, the flow in the suction direction is immediately formed in the second side port 82. Therefore, it is possible to prevent the amount of hydraulic oil sucked from the second side port 82 into the pump chamber 41 from decreasing, and it is possible to improve the suction characteristics of the vane pump 100.

In the above vane pump 100, the start end 82a of the second side port 82 is formed ahead of the start end 74a of the first side port 74 in the rotational direction, but the start end 74a of the first side port 74 is the start end 82a of the side port 82. It may be formed forward in the rotation direction.

Further, in the vane pump 100, the first side port 74 is formed by the recess 75 of the first side plate 70 and the notch 43 of the cam ring 40, but the first side port 74 is not limited to this form. For example, the cam ring 40 may not have a notch 43, and the first side port 74 may be formed by a recess 75 of the first side plate 70 and a planar end surface 40b of the cam ring 40. .. The recessed portion 75 may not be formed in the first side plate 70, and the first side port 74 may be formed by the flat side surface 70a of the first side plate 70 and the notch 43 of the cam ring 40. Further, the first side port 74 may be formed by a hole penetrating the first side plate 70.

Similarly, in the vane pump 100, the second side port 82 is formed by the recess 83 of the second side plate 80 and the notch 44 of the cam ring 40, but the second side port 82 is not limited to this form. .. For example, the cam ring 40 may not have a notch 44, and the second side port 82 may be formed by a recess 83 of the second side plate 80 and a planar end surface 40c of the cam ring 40. .. The notch 44 may not be formed in the second side plate 80, and the second side port 82 may be formed by the flat side surface 80a of the second side plate 80 and the notch 44 of the cam ring 40. Further, the second side port 82 may be formed by a hole penetrating the second side plate 80.

<Second Embodiment>
Next, the vane pump 200 according to the second embodiment of the present invention will be described with reference to FIGS. 9 and 10. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 9 is a cross-sectional view of the vane pump 200. The vane pump 200 includes a cam ring 240 that houses the rotor 20 and the vane 30, and a first side plate 270 and a second side plate 280 that are arranged so as to sandwich the rotor 20 and the cam ring 240 in the axial direction.

FIG. 10 is a side view of the cam ring 240, the first side plate 270 and the second side plate 280, and shows a state in which the first side plate 270 and the second side plate 280 are assembled to the cam ring 240.

As shown in FIGS. 9 and 10, the cam ring 240 and the first side plate 270 are provided with a first side port 274 as a first suction port for guiding the hydraulic oil in the fluid chamber 54 to the pump chamber 41. The first side port 274 is formed by a recess 275 of the first side plate 270 and a notch 243 of the cam ring 240.

The cam ring 240 and the second side plate 280 are provided with a second side port 282 as a first suction port for guiding the hydraulic oil in the low pressure chamber 61 to the pump chamber 41. The second side port 282 is formed by a recess 283 of the second side plate 280 and a notch 244 of the cam ring 240.

Further, the cam ring 240 is provided with a center port 245 as a second suction port for guiding the hydraulic oil in the low pressure chamber 61 to the pump chamber 41 through the fluid chamber 54. That is, the low pressure chamber 61 communicates with the pump chamber 41 through each of the first side port 274, the second side port 282, and the center port 245.

The center port 245 is formed by a hole 246 penetrating between the outer peripheral surface 240d of the cam ring 240 and the inner peripheral cam surface 240a. The hydraulic oil sucked from the center port 245 flows into the central portion of the pump chamber 41 in the axial direction.

The start end 245a of the center port 245 is formed in front of the start end 274a of the first side port 274 and the start end 282a of the second side port 282 in the rotational direction. The terminal 245b of the center port 245 is formed behind the terminal 274a of the first side port 274 and the terminal 282a of the second side port 282 in the rotational direction.

The "starting end" of the center port 245 means the end portion 245a of the end portion of the center port 245 located rearward in the rotation direction. Further, the "termination" of the center port 245 means an end portion 245b located forward in the rotation direction among the end portions of the center port 245. That is, when the vane pump 200 operates, the pump chamber 41 that has moved into the expansion regions 42a and 42c reaches the start end 245a, so that the pump chamber 41 and the center port 245 communicate with each other. When the pump chamber 41 passes through the terminal 245b of the center port 245, the communication between the pump chamber 41 and the center port 245 is cut off.

Since the start end 245a of the center port 245 is formed ahead of the start end 274a of the first side port 274 and the start end 282a of the second side port 282 in the rotational direction, the pump chamber 41 is formed on the first side before reaching the center port 245. It reaches port 274 and second side port 282. Therefore, even if the pump chamber 41 reaches the first side port 274 and the second side port 282 while the pressure of the hydraulic oil in the pump chamber 41 is high, the hydraulic oil in the pump chamber 41 remains in the first side port 274 and the second side port 282. 2 Only the side port 282 is discharged, and the center port 245 does not form a flow in the discharge direction.

When the rotor 20 rotates to expand the pump chamber 41 and the hydraulic oil in the pump chamber 41 is discharged from the first side port 274 and the second side port 282, the pressure in the pump chamber 41 decreases. When the rotor 20 further rotates and the pump chamber 41 reaches the center port 245, the pressure in the pump chamber 41 is sufficiently reduced.

Since the flow in the discharge direction is formed in the first side port 274 and the second side port 282, the flow in the suction direction is formed in the first side port 274 and the second side port 282 due to the inertia of the working fluid. It may take some time to complete. Since the flow in the discharge direction is not formed in the center port 245, a flow in the suction direction is immediately formed in the center port 245 when the pump chamber 41 reaches the center port 245. Therefore, it is possible to prevent the amount of hydraulic oil sucked from the center port 245 into the pump chamber 41 from decreasing, and it is possible to improve the suction characteristics of the vane pump 200.

Since the hydraulic oil sucked from the center port 245 flows into the central portion of the pump chamber 41 in the axial direction, the hydraulic oil can be distributed to the central portion of the pump chamber 41, and the suction characteristics of the vane pump 200 can be further improved. Can be done.

As used herein, the term "center" is not limited to the exact center, which means a position equidistant from the end faces 240b, 240c of the cam ring 240, but from the exact center to some extent (for example, between the end faces 240b and the end faces 240c). Includes positions that are biased toward either the end faces 240b or 240c) (about 30% of the dimensions).

In the vane pump 200, the first side port 274 communicates the low pressure chamber 61 and the pump chamber 41 via the fluid chamber 54, while the second side port 282 directly communicates the low pressure chamber 61 and the pump chamber 41. .. That is, the first passage 276 from the low pressure chamber 61 to the pump chamber 41 through the first side port 274 is longer than the second passage 284 from the low pressure chamber to the pump chamber 41 through the second side port 282. Further, while the second passage 284 is formed substantially linearly, a curved portion is formed in the first passage 276.

It is known that the resistance applied to the fluid passing through the passage depends on the length of the passage, the cross-sectional area of the passage, the shape of the passage, and the like. It is also known that the flow rate of fluid through the passage depends on the resistance of the passage.

In the vane pump 200, the first passage 276 is longer than the second passage 284 and has a curved portion. Therefore, the resistance of the first passage 276 is larger than the resistance of the second passage 284, and the flow rate of the hydraulic oil in the first passage 276 is smaller than the flow rate of the hydraulic oil in the second passage 284. Since the flow rate of the hydraulic oil sucked from the first side port 274 into the pump chamber 41 is smaller than the flow rate of the hydraulic oil sucked from the second side port 282, the side of the first side port 274 is closer to the exact center of the pump chamber 41. The hydraulic oil is likely to run out in the part located in.

In such a vane pump 200, the center port 245 is preferably formed at a position biased toward the first side port 274 on the cam ring 240. Specifically, the center port 245 is preferably formed on the side of the first side port 274 rather than the exact center of the cam ring 240. By biasing the center port 245, the hydraulic oil sucked from the center port 245 flows into the portion of the pump chamber 41 that is biased toward the first side port 274. As a result, the hydraulic oil is distributed throughout the pump chamber 41, and the suction characteristics of the vane pump 200 can be further improved.

When the resistance of the first passage 276 and the resistance of the second passage 284 are equal and the hydraulic oil is likely to be insufficient in the central portion of the pump chamber 41, the center port 245 is preferably formed in the center of the cam ring 240. More preferably, it is formed in the exact center of the cam ring 240. By forming the center port 245 in the center of the cam ring 240, the hydraulic oil sucked from the center port 245 flows into the central portion of the pump chamber 41. The hydraulic oil is distributed throughout the pump chamber 41, and the suction characteristics of the vane pump 200 can be further improved.

The start end 274a of the first side port 274 and the start end 245a of the center port 245 are separated from each other by a predetermined angle θ about the rotation axis of the rotor 20. The predetermined angle θ is set within the range of the above equation (2). It is possible to prevent a flow in the discharge direction from being formed in the center port 245, and it is possible to more reliably improve the suction characteristics of the vane pump 200.

The center port 245 is preferably provided in the first half of the expansion regions 42a and 42c. While the pump chamber 41 passes through the first half of the expansion regions 42a and 42c, the hydraulic oil is distributed to the central portion of the pump chamber 41, and the suction characteristics of the vane pump 200 can be further improved.

The opening of the hole 246 formed on the inner peripheral cam surface 240a of the cam ring 240 is larger than the opening of the hole 246 formed on the outer peripheral surface 240d of the cam ring 240, and the flow path area of the hole 246 is inside the cam ring 240. It is larger from the circumference to the outer circumference. Since the outer peripheral opening of the hole 246 is large, hydraulic oil can be easily guided from the fluid chamber 54 to the hole 246, and the suction characteristics of the vane pump 200 can be further improved.

Since the operation of the vane pump 200 is substantially the same as the operation of the vane pump 100, the description thereof will be omitted here.

In the above vane pump 200, the start end 245a of the center port 245 is formed in front of the start ends 274a and 282a of the first side port 274 and the second side port 282 in the rotational direction, but the present invention is not limited to this form. Any one of the start ends 274a, 282a, 245a of the first side port 274 and the second side port 282 and the center port 245 may be formed in front of the other start ends in the rotational direction.

Further, in the vane pump 200, the first side port 274 is formed by the recessed portion 275 of the first side plate 270 and the notch 243 of the cam ring 40, but the present invention is not limited to this form. Similarly, the second side port 282 is formed by the recess 283 of the second side plate 280 and the notch 244 of the cam ring 240, but is not limited to this form.

Hereinafter, the configurations, actions, and effects of the embodiments of the present invention will be collectively described.

In the present embodiment, the vane pumps 100 and 200 include a rotor 20 that is rotationally driven, a plurality of vanes 30 that are reciprocally reciprocated in the radial direction of the rotor 20, and a plurality of vanes that accompany the rotation of the rotor 20. The first side plates 70, 270 and the second side plates 80, which are arranged so as to sandwich the rotor 20 and the cam rings 40, 240, and the cam rings 40, 240 having inner peripheral cam surfaces 40a, 240a with which the tip portion 31 of the 30 is in sliding contact. In at least one of the 280, the pump chamber 41 defined by the rotor 20, the cam rings 40, 240, and the adjacent vanes 30, the cam rings 40, 240, the first side plates 70, 270 and the second side plates 80, 280. The first side ports 74, 274, the second side ports 82, 282, and the center port 245, which are formed and guide the hydraulic oil to the pump chamber 41, are provided, and the starting ends 82a and 245a of the second side port 82 and the center port 245 are , The first side ports 74, 274 and the second side ports 282 are formed in front of the starting ends 74a, 274a, 282a in the rotation direction of the rotor 20.

In this configuration, the start ends 82a and 245a of the second side port 82 and the center port 245 are formed ahead of the start ends 74a, 274a and 282a of the first side ports 74 and 274 and the second side port 282 in the rotation direction. The pump chamber 41 reaches the first side ports 74 and 274 and the second side port 282 before reaching the second side port 82 and the center port 245. Therefore, even if the pump chamber 41 reaches the first side ports 74, 274 and the second side port 282 without reducing the pressure of the hydraulic oil remaining in the pump chamber 41 without being discharged from the discharge port 72 in the contraction region. The hydraulic oil in the pump chamber 41 is discharged only from the first side ports 74 and 274 and the second side port 282, and the flow in the discharge direction is not formed at the second side port 82 and the center port 245. When the pump chamber 41 reaches the second side port 82 and the center port 245, a flow in the suction direction is immediately formed at the second side port 82 and the center port 245. Therefore, the suction characteristics of the vane pumps 100 and 200 can be improved.

Further, in the present embodiment, the first side ports 74 and 274 and the second side port 282 are the first side port 274 formed by the first side plate 270 and the cam ring 240, and the second side plate 280 and the cam ring 240. A second side port 282 formed by the above, and a second side port 82 and a center port 245 are formed by a hole 246 penetrating between the outer peripheral surface 240d and the inner peripheral cam surface 240a of the cam ring 240. Center port 245.

In this configuration, the start end 245a of the center port 245 is formed ahead of the start ends 274a and 282a of the first side port 274 and the second side port 282 in the rotational direction, so that when the pump chamber 41 reaches the center port 245, it is formed. Immediately forms a flow in the suction direction at the center port 245. Therefore, the hydraulic oil can be distributed to the central portion of the pump chamber 41, and the suction characteristics of the vane pump 200 can be further improved.

Further, in the present embodiment, the vane pump 200 further includes a low pressure chamber 61 communicating with the pump chamber 41 through each of the first side port 274 and the second side port 282, and the pump chamber is further provided from the low pressure chamber 61 through the first side port 274. The resistance of the first passage 276 to 41 and the resistance of the second passage 284 from the low pressure chamber 61 to the pump chamber 41 through the second side port 282 are equal, with the center port 245 at the center of the cam ring 240 in the axial direction. It is formed.

In this configuration, since the center port 245 is formed in the center of the cam ring 240 in the axial direction, the hydraulic oil is distributed to the central portion of the pump chamber 41. Therefore, the suction characteristics of the vane pump 200 can be improved more reliably.

Further, in the present embodiment, the vane pump 200 further includes a low pressure chamber 61 communicating with the pump chamber 41 through each of the first side port 274 and the second side port 282, and the pump chamber is further provided from the low pressure chamber 61 through the first side port 274. The resistance of the first passage 276 leading to 41 is larger than the resistance of the second passage 284 leading from the low pressure chamber 61 to the pump chamber 41 through the second side port 282, and the center port 245 is biased toward the first side port 274. Will be done.

In this configuration, since the center port 245 is formed unevenly toward the first side port 274, the hydraulic oil is distributed to the portion of the pump chamber 41 that is biased toward the first side port 274. Therefore, the suction characteristics of the vane pump 200 can be improved more reliably.

Further, in the present embodiment, the starting ends 74a, 274a, 282a of the first side ports 74, 274 and the second side port 282 and the starting ends 82a, 245a of the second side port 82 and the center port 245 are the rotation shafts of the rotor 20. A predetermined angle θ is separated from the center of the pump chamber, and the predetermined angle θ is set after the pump chamber 41 reaches the start ends 74a, 274a, 282a of the first side ports 74, 274 and the second side port 282. This is the angle at which the rotor 20 rotates before the pressure of 41 drops.

In this configuration, the starting ends 74a, 274a, 282a of the first side ports 74, 274 and the second side port 282 and the starting ends 82a, 245a of the second side port 82 and the center port 245 are centered on the rotation axis of the rotor 20. The above-mentioned predetermined angle θ is separated. Therefore, when the pump chamber 41 reaches the second side port 82 and the center port 245, the pressure in the pump chamber 41 is sufficiently reduced. Therefore, it is possible to more reliably prevent the formation of a flow in the discharge direction at the second side port 82 and the center port 245, and it is possible to more reliably improve the suction characteristics of the vane pumps 100 and 200.

Further, in the present embodiment, when the predetermined angle is θ, the predetermined angle θ is within the range obtained by the following equation.

0 <θ [deg] ≤7α + 10
However, α: The ratio of the minimum volume of the pump chamber 41 to the maximum volume of the pump chamber 41

In this configuration, since the predetermined angle θ is larger than 0 (zero), the pressure in the pump chamber 41 is sufficiently reduced when the pump chamber 41 reaches the second side port 82 and the center port 245. Therefore, it is possible to prevent the flow in the discharge direction from being formed in the second side port 82 and the center port 245. Further, since the predetermined angle θ is equal to or less than the angle obtained by 7α + 10, the start ends 82a and 245a of the second side port 82 and the center port 245 are the start ends 74a of the first side ports 74 and 274 and the second side port 282. , 274a, 282a are not formed forward in the rotation direction beyond the expected delay of pressure drop. It is possible to prevent the second side port 82 and the center port 245 from becoming too small and reducing the amount of hydraulic oil sucked into the pump chamber 41 from the second side port 82 and the center port 245. Therefore, the suction characteristics of the vane pumps 100 and 200 can be improved more reliably.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. Absent.

20 ... rotor, 30 ... vane, 40 ... cam ring, 40a ... inner circumference cam surface, 41 ... pump chamber, 70 ... first side plate (first side member), 74 ... 1st side port (1st suction port), 74a ... Start end, 80 ... 2nd side plate (2nd side member), 82 ... 2nd side port (2nd suction port), 82a ... Start end, 100, 200 ... Vane pump, 240 ... Cam ring, 240a ... Inner peripheral cam surface, 240d ... Outer surface, 245 ... Center port (second suction port), 245a ... Starting end, 246 ... Hole, 270 ... First side plate (first side member), 274 ... First side port (first suction port), 274a ... Starting end, 280 ... -Second side plate (second side member), 282 ... Second side port (first suction port)

Claims (6)

It ’s a vane pump,
Rotationally driven rotor and
A plurality of vanes provided on the rotor so as to be reciprocating in the radial direction of the rotor,
A cam ring having an inner cam surface on which the tips of the plurality of vanes are in sliding contact with each other as the rotor rotates.
The first and second side members arranged so as to sandwich the rotor and the cam ring,
A pump chamber defined by the rotor, the cam ring, and adjacent vanes.
A first and second suction port formed on at least one of the cam ring, the first side member and the second side member, and guiding a working fluid to the pump chamber.
A vane pump characterized in that the starting end of the second suction port is formed in front of the starting end of the first suction port in the rotational direction. The vane pump according to claim 1.
The first suction port includes a first side port formed by the first side member and the cam ring, and a second side port formed by the second side member and the cam ring.
The second suction port is a vane pump characterized by being a center port formed by a hole penetrating between the outer peripheral surface of the cam ring and the inner peripheral cam surface. The vane pump according to claim 2.
A low pressure chamber communicating with the pump chamber through each of the first side port and the second side port is further provided.
The resistance of the first passage from the low pressure chamber to the pump chamber through the first side port is equal to the resistance of the second passage from the low pressure chamber to the pump chamber through the second side port.
A vane pump characterized in that the center port is formed at the center of the cam ring in the axial direction. The vane pump according to claim 2.
A low pressure chamber communicating with the pump chamber through each of the first side port and the second side port is further provided.
The resistance of the first passage from the low pressure chamber to the pump chamber through the first side port is larger than the resistance of the second passage from the low pressure chamber to the pump chamber through the second side port.
The center port is a vane pump characterized in that it is formed unevenly on the first side port. The vane pump according to any one of claims 1 to 4.
The start end of the first suction port and the start end of the second suction port are separated from each other by a predetermined angle about the rotation axis of the rotor, and the pump chamber is the first suction port at the predetermined angle. A vane pump characterized in that the angle at which the rotor rotates from the time when the start end of the pump chamber is reached until the pressure in the pump chamber drops. The vane pump according to claim 5.
A vane pump characterized in that, when the predetermined angle is θ, the predetermined angle is within the range obtained by the following equation.
0 <θ [deg] ≤7α + 10
However, α: The ratio of the minimum volume of the pump chamber to the maximum volume of the pump chamber

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