JP7116626B2 - Variable displacement vane pump - Google Patents

Description

The present invention relates to a variable displacement vane pump.

A variable displacement vane pump is known as a fluid pressure supply source for fluid pressure equipment mounted on a vehicle.

A variable displacement vane pump disclosed in Patent Document 1 includes a control valve that controls the amount of eccentricity of a cam ring. The control valve is configured to reduce the amount of eccentricity as the pressure difference across the throttle portion in the discharge passage increases. The difference in pressure before and after the throttling portion increases as the flow rate of the working fluid in the discharge passage, that is, the discharge flow rate, increases. The volume is reduced and the displacement of the pump is reduced. Therefore, the discharge flow rate is kept substantially constant regardless of the rotation speed of the rotor.

Further, the throttle section in Patent Document 1 includes a fixed orifice and an electromagnetic on-off valve that are provided in parallel with each other. When the electromagnetic on-off valve is opened and closed in response to a command from the controller, the flow passage cross-sectional area of the restrictor increases or decreases, and the pressure difference across the restrictor increases or decreases. Thereby, the minimum flow characteristic and the maximum flow characteristic of the variable displacement vane pump are set.

JP 2014-70541 A

The variable displacement vane pump disclosed in Patent Document 1 requires a space for providing the fixed orifice and the electromagnetic on-off valve, which increases the size of the variable displacement vane pump.

An object of the present invention is to reduce the size of a variable displacement vane pump.

The present invention comprises a rotor, a plurality of vanes, a cam ring, a discharge passage, an electromagnetic valve provided in the discharge passage and allowing a working fluid to flow in the discharge passage when the flow passage cross-sectional area is minimized, and a discharge passage. an eccentricity amount control valve for controlling the amount of eccentricity of the cam ring according to the pressure difference before and after the electromagnetic valve in the electromagnetic valve, the electromagnetic valve comprising a housing, a valve element accommodated in the housing, and a flow path a restricting part that restricts the movement of the valve body in the direction of decreasing the cross-sectional area to define a state in which the cross-sectional area of the flow path is minimized, wherein the restricting part is supplied with current to the coil to cause the valve body to flow. The stepped portion restricts the movement of the valve body by coming into contact with the valve body when it moves in the direction of decreasing the cross-sectional area of the passage .

In this invention, the solenoid valve functions as a fixed orifice having a predetermined cross-sectional area of the flow path when the cross-sectional area of the flow path is minimum. Therefore, the minimum flow characteristic of the variable displacement vane pump can be set without providing a fixed orifice separately from the solenoid valve. In addition, the step portion defines a state in which the cross-sectional area of the flow path is minimized. Therefore, the minimum flow characteristic of the variable displacement vane pump can be set without controlling the current supply amount with high accuracy.

Further, according to the present invention, the solenoid valve has a pressure chamber formed by a housing and a valve body, and the valve body includes a first through hole extending axially therethrough, an inner peripheral surface of the first through hole and the valve body. a second through hole extending between the outer peripheral surface of the body, the second through hole defining a minimum flow cross-sectional area.

In this invention, the flow path resistance of the first through hole can be reduced. Therefore, it is possible to reduce the force acting on the valve body due to the pressure difference between the upstream port or the downstream port and the pressure chamber while setting the minimum flow rate characteristic of the variable displacement vane pump with the solenoid valve.

Further, according to the present invention, the valve body has a shaft inserted into one of the upstream port and the downstream port in a state in which movement is restricted by the restricting portion, and the outer peripheral surface of the shaft and the one port The minimum flow passage cross-sectional area is defined by the distance from the inner peripheral surface of

According to the present invention, it is possible to allow the precision of the valve body and the positional deviation of the restricting portion with respect to one of the ports when manufacturing the solenoid valve. Therefore, the minimum cross-sectional area of the flow path of the solenoid valve can be set with high accuracy, and variations in minimum flow rate characteristics in the vane pump can be reduced.

ADVANTAGE OF THE INVENTION According to this invention, a variable displacement vane pump can be reduced in size.

FIG. 1 is a configuration diagram of a variable displacement vane pump according to a first embodiment of the present invention. FIG. 2 is a graph showing flow characteristics of the variable displacement vane pump according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view of the solenoid valve shown in FIG. 1, showing a state in which the flow passage cross-sectional area is maximum. FIG. 4 is a cross-sectional view of the solenoid valve shown in FIG. 1, showing a state in which the cross-sectional area of the flow path is minimum. FIG. 5 is a sectional view of an electromagnetic valve of a variable displacement vane pump according to a second embodiment of the invention. FIG. 6 is a sectional view of an electromagnetic valve of a variable displacement vane pump according to a third embodiment of the invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
First, a variable displacement vane pump 100 (hereinafter also simply referred to as "vane pump 100") according to a first embodiment will be described with reference to FIGS. 1 to 4. FIG. The vane pump 100 is used as a supply source for supplying hydraulic fluid to a fluid pressure device 1 (for example, a power steering device, a continuously variable transmission, etc.) mounted on a vehicle or industrial machine.

The vane pump 100 includes a rotationally driven rotor 10 , a plurality of vanes 20 radially reciprocatingly provided on the rotor 10 , and a cam ring 30 housing the rotor 10 and the vanes 20 . The rotor 10 is connected to a drive shaft 2 of an engine (not shown), and rotates together with the drive shaft 2 when driven by the engine.

The vanes 20 are urged radially outward by centrifugal force as the rotor 10 rotates, and the tip portions 21 of the vanes 20 slide along the inner peripheral surface 31 of the cam ring 30 . The rotor 10 and the cam ring 30 are provided between a pump body and a pump cover (not shown), and a plurality of pump chambers 30a partitioned by the vanes 20 are formed between the rotor 10 and the cam ring 30. be.

Cam ring 30 is eccentric with respect to the center of rotor 10 . Therefore, the vanes 20 reciprocate with the rotation of the rotor 10, and the pump chamber 30a expands and contracts. As the pump chamber 30a expands, the hydraulic oil in the tank 3 is sucked into the pump chamber 30a through the suction passage 3a and a suction port (not shown). As the pump chamber 30a shrinks, hydraulic oil is discharged from the pump chamber 30a through a discharge port (not shown). The discharged hydraulic fluid is guided to the discharge passage 3b and supplied to the fluid pressure device 1. As shown in FIG.

The displacement volume of vane pump 100 changes according to the amount of eccentricity of cam ring 30 . Specifically, as the amount of eccentricity decreases, the displacement decreases. As the eccentricity increases, the displacement increases. The displacement volume corresponds to the amount of hydraulic oil discharged per rotation of the rotor 10 . FIG. 1 shows the state where the cam ring 30 is maximally eccentric and the displacement of the vane pump 100 is maximal.

A configuration for changing the amount of eccentricity of the cam ring 30 will be described.

The vane pump 100 comprises an annular adapter ring 40 surrounding the cam ring 30 and a control valve 50 controlling pressure between the cam ring 30 and the adapter ring 40 . The control valve 50 is provided on the pump body or pump cover of the vane pump 100 .

The adapter ring 40 swingably supports the cam ring 30 via the support pin 41 . As the cam ring 30 swings with respect to the adapter ring 40, the amount of eccentricity with respect to the center of the rotor 10 changes.

A space between the cam ring 30 and the adapter ring 40 is partitioned into a first fluid pressure chamber 40a and a second fluid pressure chamber 40b by a support pin 41 and a seal member 42 provided on the inner circumference of the adapter ring 40. It is When the cam ring 30 swings in the direction in which the first fluid pressure chamber 40a expands and the second fluid pressure chamber 40b contracts (to the right in FIG. 1), the amount of eccentricity decreases. When the cam ring 30 swings in the direction in which the first fluid pressure chamber 40a contracts and the second fluid pressure chamber 40b expands (leftward in FIG. 1), the eccentricity increases.

The swinging motion of the cam ring 30 is caused by the pressure difference between the first fluid pressure chamber 40a and the second fluid pressure chamber 40b. The first fluid pressure chamber 40a and the second fluid pressure chamber 40b are connected to the tank 3 via the control valve 50, and the pressures in the first fluid pressure chamber 40a and the second fluid pressure chamber 40b control the control valve 50. controlled using

The control valve 50 is selectively switched to the first position 50a or the second position 50b according to the pressure difference across the solenoid valve 60 provided in the discharge passage 3b. In the first position 50 a , the control valve 50 allows communication between the first fluid pressure chamber 40 a and the tank 3 while blocking communication between the second fluid pressure chamber 40 b and the tank 3 . In the second position 50 b , the control valve 50 blocks communication between the first fluid pressure chamber 40 a and the tank 3 while permitting communication between the second fluid pressure chamber 40 b and the tank 3 through the variable throttle 51 . The variable throttle 51 is formed such that the larger the pressure difference across the solenoid valve 60, the larger the opening area.

The control valve 50 is connected upstream of the electromagnetic valve 60 in the discharge passage 3b, and allows communication between the discharge passage 3b and the first fluid pressure chamber 40a at the second position 50b. The second fluid pressure chamber 40b is connected upstream of the electromagnetic valve 60 in the discharge passage 3b through a fixed throttle 3c.

The operation and flow characteristics of the vane pump 100 will be described with reference to FIGS. 1 and 2. FIG.

When the rotation speed N of the rotor 10 is low (for example, when the vane pump 100 is started), the flow rate of hydraulic oil in the discharge passage 3b is small and the pressure difference across the solenoid valve 60 is small. Therefore, the control valve 50 is maintained at the first position 50 a by the biasing force of the return spring 52 .

At this time, the first fluid pressure chamber 40a communicates with the tank 3 through the control valve 50, and the pressure inside the first fluid pressure chamber 40a becomes the tank pressure. On the other hand, communication between the second fluid pressure chamber 40b and the tank 3 is cut off by the control valve 50 . Since hydraulic fluid in the discharge passage 3b is led to the second fluid pressure chamber 40b, the cam ring 30 is urged leftward in FIG. be done. As a result, the displacement volume of the vane pump 100 is maximized.

When the displacement is at its maximum, the discharge flow rate Q increases approximately in proportion to the rotational speed N of the rotor 10 (characteristic AB in FIG. 2). As the discharge flow rate Q increases, the pressure difference across the solenoid valve 60 increases. When the pressure difference across the solenoid valve 60 reaches a predetermined value, the control valve 50 is switched to the second position 50b against the biasing force of the return spring 52.

The rotation speed N of the rotor 10 at which the pressure difference across the electromagnetic valve 60 reaches a predetermined value changes as the flow passage cross-sectional area of the electromagnetic valve 60 changes. Specifically, the smaller the passage cross-sectional area of the solenoid valve 60, the smaller the rotation speed N of the rotor 10 at which the pressure difference across the solenoid valve 60 reaches a predetermined value.

In FIG. 2, N1 is the rotation speed N of the rotor 10 at which the pressure difference before and after the solenoid valve 60 becomes a predetermined value when the flow passage cross-sectional area of the solenoid valve 60 is maximized. As the cross-sectional area of the flow path of the solenoid valve 60 is reduced, the rotational speed N of the rotor 10 at which the pressure difference across the solenoid valve 60 reaches a predetermined value decreases (for example, N2 in FIG. 2).

When the pressure difference across the electromagnetic valve 60 reaches a predetermined value and the control valve 50 is switched to the second position 50b, the control valve 50 blocks the communication between the first fluid pressure chamber 40a and the tank 3. , permit communication between the first fluid pressure chamber 40a and the discharge passage 3b. Therefore, the pressure in the first fluid pressure chamber 40a increases. Also, the control valve 50 allows communication between the second fluid pressure chamber 40 b and the tank 3 through the variable throttle 51 . Therefore, the pressure in the second fluid pressure chamber 40b decreases, and the cam ring 30 swings rightward in FIG. 1 due to the pressure in the first fluid pressure chamber 40a. As a result, the eccentricity is reduced and the displacement of the vane pump 100 is reduced.

The variable throttle 51 of the control valve 50 is formed so that the opening area increases as the pressure difference across the electromagnetic valve 60 increases. Therefore, when the rotation speed N of the rotor 10 further increases, the opening area of the variable throttle 51 increases, and the pressure in the second fluid pressure chamber 40b further decreases. As a result, the eccentricity is further reduced and the displacement of the vane pump 100 is further reduced.

In this manner, in the vane pump 100, as the rotation speed N of the rotor 10 increases, the eccentricity of the control valve 50 is decreased to decrease the displacement volume of the vane pump 100. FIG. Therefore, when the rotation speed N of the rotor 10 is equal to or higher than a predetermined value, the discharge flow rate of the vane pump 100 is substantially constant regardless of the rotation speed N of the rotor 10 (characteristics BC and D in FIG. 2). -E characteristics).

As described above, when the flow passage cross-sectional area of the solenoid valve 60 is maximum, the control valve 50 is switched to the second position 50b when the rotation speed N of the rotor 10 is N1 or higher, and the eccentricity of the cam ring 30 changes. do. Therefore, the flow characteristic of the vane pump 100 is the BC characteristic. The maximum flow rate characteristic of the vane pump 100 is the characteristic (ABC characteristic) obtained when the flow passage cross-sectional area of the solenoid valve 60 is maximized.

When current is supplied from the controller 70 to the coil 61 of the solenoid valve 60 and the valve body 67 (see FIG. 3) moves against the biasing force of the spring 62, the flow passage cross-sectional area of the solenoid valve 60 is reduced. As a result, the rotational speed N of the rotor 10 at which the pressure difference across the electromagnetic valve 60 reaches a predetermined value becomes N2, and the flow rate characteristic of the vane pump 100 becomes the DE characteristic.

As described above, in the vane pump 100, the flow rate characteristic can be changed by changing the magnitude of the current supplied from the controller 70 to the coil 61 to change the flow passage cross-sectional area of the solenoid valve 60. FIG. Therefore, hydraulic oil can be supplied to the fluid pressure device 1 at an appropriate flow rate while the vehicle is running.

The solenoid valve 60 is formed so as to allow the hydraulic oil to flow through the discharge passage 3b when the flow passage cross-sectional area is minimized. Therefore, the solenoid valve 60 functions as a fixed orifice having a predetermined flow passage cross-sectional area. Therefore, the flow characteristic of the vane pump 100 can be set to the minimum flow characteristic indicated by FG without providing a fixed orifice separately from the solenoid valve 60, and the vane pump 100 can be miniaturized. N3 is the rotation speed N of the rotor 10 at which the pressure difference before and after the solenoid valve 60 becomes a predetermined value when the flow passage cross-sectional area of the solenoid valve 60 is the minimum.

If, instead of the solenoid valve 60, a solenoid valve that cuts off the flow of hydraulic oil in a state where the cross-sectional area of the channel is the smallest, that is, a solenoid valve that can make the cross-sectional area of the channel 0 (zero), the solenoid valve A fixed orifice must be provided in parallel with the In this case, a space for providing the fixed orifice is required, and the vane pump becomes large.

Further, in a solenoid valve that is capable of blocking the flow of hydraulic oil, the flow of hydraulic oil changes significantly immediately before the valve closes and immediately after the valve opens. Therefore, the pressure difference across the valve body increases when the valve is closed and when the valve is opened, and the force acting on the valve body due to the pressure of the hydraulic oil increases. In other words, a large force is required to open and close the solenoid valve. As a result, the coil becomes large.

In addition, even if the solenoid valve is designed so that the minimum cross-sectional area of the flow path is 0 (zero), there are variations in the dimensions of parts such as the valve body and valve seat during manufacturing, so the valve may not close. Hydraulic oil may leak under certain conditions. Fixed orifices also have dimensional variations during manufacture. Therefore, in a configuration in which a solenoid valve and a fixed orifice are provided in parallel with each other and the cross-sectional area of the flow path is minimized by closing the solenoid valve, the minimum flow rate characteristic is determined by both the fixed orifice variation and the solenoid valve variation. impacted and the variability increases.

In the vane pump 100 according to the present embodiment, as described above, the minimum flow rate characteristic of the vane pump 100 can be set without providing a fixed orifice separately from the solenoid valve 60, so the vane pump 100 can be miniaturized.

In addition, since the solenoid valve 60 allows the flow of hydraulic oil in a state where the cross-sectional area of the flow path is minimized, it is possible to prevent a state in which the flow of hydraulic oil is significantly throttled. Therefore, it is possible to prevent the pressure difference across the valve body 67 from increasing when the solenoid valve 60 is operating, and to reduce the force acting on the valve body 67 due to the pressure of the hydraulic oil. As a result, the force required to move the valve body 67 can be reduced, and the coil 61 can be miniaturized.

Also, the minimum flow rate characteristic of the vane pump 100 is set by the minimum flow passage cross-sectional area of the solenoid valve 60 . Therefore, the only factor affecting variations in the minimum flow rate characteristic is the variation in the minimum cross-sectional area of the flow path of the solenoid valve 60, and the variation in the minimum flow rate characteristic can be reduced.

The structure of the solenoid valve 60 will be explained in more detail with reference to FIGS. 3 and 4. FIG. FIG. 3 shows a state in which current is not supplied to the coil 61 and the flow path cross-sectional area of the solenoid valve 60 is maximized. FIG. 4 shows a state in which current is supplied to the coil 61 and the passage cross-sectional area of the solenoid valve 60 is minimized.

As shown in FIGS. 3 and 4, the solenoid valve 60 has a housing 63 that accommodates a valve body 67 and a spring 62 . The spring 62 is a coil spring, and the valve body 67 is accommodated in the housing 63 with the spring 62 inserted. Further, the housing 63 holds the coil 61 via a bobbin 61a made of resin material.

The bobbin 61a has a tubular portion provided on the inner periphery of the coil 61 and flanges provided on both ends of the tubular portion. there is The outer circumference of the coil 61 and one flange of the bobbin 61a are covered with a cover member 61b, and the other flange of the bobbin 61a is covered with an annular plate member 61c.

The valve body 67 has a plunger 68 made of a magnetic material and a shaft 69 made of a non-magnetic material. The shaft 69 is fixed to the plunger 68 while passing through the plunger 68 and moves together with the plunger 68 . The plunger 68 and the shaft 69 are accommodated in the housing 63 so that the central axis of the coil 61 and the central axis of the shaft 69 are substantially aligned.

The housing 63 has a holding member 64 that slidably holds the plunger 68 via a bush (not shown), and a base member 65 that is spaced apart from the holding member 64 in the axial direction of the shaft 69 . The holding member 64 and the base member 65 are connected to each other using a tubular connecting member 66 .

The holding member 64 is formed with a hole portion 64b that opens in one end surface 64a facing the base member 65, and a plug hole 64e that penetrates between the bottom surface 64c of the hole portion 64b and the other end surface 64d. there is A bush (not shown) is provided on the inner periphery of the hole portion 64b, and a plunger 68 is inserted into the hole portion 64b. A pressure chamber 64 g is defined by the plunger 68 and the hole 64 b of the holding member 64 .

A plug 64f is fixed to the plug hole 64e by screwing, and the plug hole 64e is closed by the plug 64f. The plug 64f protrudes from the plug hole 64e into the hole 64b, and restricts movement of the shaft 69 and the plunger 68 toward the bottom surface 64c of the hole 64b (rightward in FIG. 3). The plug 64f may not protrude into the hole 64b, in which case the movement of the shaft 69 and plunger 68 is restricted by the bottom surface 64c of the hole 64b.

The base member 65 includes a large-diameter hole portion 65b that opens in one end face 65a facing the holding member 64, a medium-diameter hole portion 65c that is formed continuously with the large-diameter hole portion 65b, and the medium-diameter hole portion 65c. and a continuously formed small-diameter hole portion 65d. The large-diameter hole portion 65b, medium-diameter hole portion 65c, and small-diameter hole portion 65d are provided coaxially.

The inner diameter of the large-diameter hole 65b is substantially the same as the outer diameter of the plunger 68, similarly to the hole 64b of the holding member 64, and the plunger 68 can move along the inner circumference of the large-diameter hole 65b. The inner diameter of the medium-diameter hole portion 65c is smaller than the inner diameter of the large-diameter hole portion 65b. A portion 65e is formed.

The base member 65 is made of a magnetic material and guides the magnetic flux formed by the excitation of the coil 61 . The stepped portion 65e of the base member 65 faces the plunger 68, and when the coil 61 is excited, the plunger 68 is attracted toward the stepped portion 65e (leftward in FIG. 3). In other words, the plunger 68 moves toward the stepped portion 65e according to the magnetic field formed by supplying current to the coil 61. As shown in FIG.

The inner diameter of the small-diameter hole portion 65d of the base member 65 is smaller than the inner diameter of the medium-diameter hole portion 65c, and a stepped portion 65f is formed between the small-diameter hole portion 65d and the medium-diameter hole portion 65c. A spring 62 is provided between the stepped portion 65f and the plunger 68 in a compressed state. are being forced.

The base member 65 includes a first port 65h that opens to the other end surface 65g, a connection hole portion 65i that connects the first port 65h and the small-diameter hole portion 65d, an inner peripheral surface of the connection hole portion 65i, and the base member. and a second port 65j penetrating between the outer peripheral surface of 65 and the second port 65j. The first port 65h is connected upstream in the discharge passage 3b, and the second port 65j is connected downstream in the discharge passage 3b. Hydraulic fluid discharged from the pump chamber 30a (see FIG. 1) is supplied to the fluid pressure device 1 through the first port 65h, the connection hole portion 65i and the second port 65j.

The shaft 69 is inserted through the medium diameter hole portion 65c and the small diameter hole portion 65d. When the plunger 68 slides leftward in FIG. 3 against the biasing force of the spring 62, the tip 69a of the shaft 69 is inserted into the first port 65h. This changes the cross-sectional area of the flow path between the first port 65h and the second port 65j.

The shaft 69 is formed with a first through hole 69d extending between the front end 69a and the rear end 69b, and the first port 65h communicates with the pressure chamber 64g through the first through hole 69d. Therefore, the pressure in the first port 65h and the pressure in the pressure chamber 64g become substantially the same. Therefore, the force acting on the plunger 68 and the shaft 69 due to the pressure difference between the first port 65h and the pressure chamber 64g can be reduced, and the suction force required to move the plunger 68 and the shaft 69 can be reduced. can do. Thereby, the coil 61 can be miniaturized, and the vane pump 100 can be miniaturized.

A tapered portion 69c is formed on the shaft 69 so that the outer diameter decreases toward the tip 69a. Further, the shaft 69 is formed with a second through-hole 69e penetrating between the inner peripheral surface of the first through-hole 69d and the outer peripheral surface of the shaft 69 .

As shown in FIG. 3, when the current supply to the coil 61 is stopped and the shaft 69 is pressed against the plug 64f by the spring 62, there is a gap between the opening edge of the first port 65h and the tapered portion 69c. gap is formed. Also, the second through hole 69e is located in the connection hole portion 65i. Therefore, the first port 65h and the second port 65j communicate (flow F1) through the opening edge of the first port 65h and the tapered portion 69c, and communicate through the first through hole 69d and the second through hole 69e. (flow F2).

When current is supplied to the coil 61 and the plunger 68 moves leftward in FIG. 3 against the biasing force of the spring 62, the gap between the opening edge of the first port 65h and the tapered portion 69c is reduced. As a result, the flow F1 is throttled, and the flow passage cross-sectional area of the solenoid valve 60 is reduced.

As shown in FIG. 4, when the plunger 68 has moved to contact the stepped portion 65e, the tapered portion 69c is inserted into the first port 65h, closing the outer circumference of the shaft 69 and the inner circumference of the first port 65h. be done. On the other hand, the second through hole 69e is positioned inside the connection hole portion 65i. Therefore, the first port 65h and the second port 65j communicate only through the first through hole 69d and the second through hole 69e. In other words, the channel cross-sectional area of the solenoid valve 60 can be defined by the first through hole 69d and the second through hole 69e.

The attractive force generated in the base member 65 changes according to the strength of the magnetic field formed by the coil 61 , that is, the magnitude of the current supplied to the coil 61 . Therefore, by supplying the coil 61 with a current greater than or equal to a predetermined value, the plunger 68 can be moved to the stepped portion 65e against the biasing force of the spring 62, and the flow passage cross-sectional area of the solenoid valve 60 can be reduced. can be minimal. Therefore, the minimum flow characteristic of the vane pump 100 can be set without controlling the magnitude of the current supplied to the coil 61 with high accuracy.

Also, the cross-sectional area of the second through hole 69e is smaller than the cross-sectional area of the first through hole 69d, and the minimum flow passage cross-sectional area of the solenoid valve 60 is defined by the second through hole 69e. Therefore, the cross-sectional area of the first through hole 69d can be increased to reduce the flow path resistance of the first through hole 69d. Therefore, the second through-hole 69e can set the minimum discharge flow rate of the vane pump 100 and reduce the force acting on the plunger 68 and the shaft 69 due to the pressure difference between the first port 65h and the pressure chamber 64g. can do.

According to the above embodiment, the following operational effects are obtained.

In the vane pump 100, the electromagnetic valve 60 permits the hydraulic oil to flow through the discharge passage 3b when the cross-sectional area of the flow path is the minimum. Therefore, the solenoid valve 60 functions as a fixed orifice having a predetermined flow passage cross-sectional area. Therefore, the minimum flow characteristic of the vane pump 100 can be set without providing a fixed orifice separately from the solenoid valve 60, and the vane pump 100 can be miniaturized.

Further, in the vane pump 100, the stepped portion 65e of the base member 65 restricts the movement of the shaft 69 in the direction of decreasing the cross-sectional area of the flow path, thereby defining a state in which the cross-sectional area of the flow path is minimized. Therefore, the minimum flow characteristic of the vane pump 100 can be set without controlling the magnitude of the current supplied to the coil 61 with high accuracy.

Also, in the vane pump 100 , the second through hole 69 e defines the minimum flow passage cross-sectional area of the solenoid valve 60 . Therefore, the flow path resistance of the first through holes 69d can be reduced. Therefore, the force acting on the plunger 68 and the shaft 69 due to the pressure difference between the first port 65h and the pressure chamber 64g can be reduced while setting the minimum flow rate characteristic of the vane pump 100 by the solenoid valve 60.

<Second embodiment>
Next, a variable displacement vane pump 200 (hereinafter also simply referred to as "vane pump 200") according to a second embodiment will be described with reference to FIG. In the following, differences from the first embodiment will be mainly described, and the same or corresponding configurations as those described in the first embodiment will be denoted by the same reference numerals as those in the first embodiment. Description is omitted. Also, the configuration diagram of the vane pump 200 is omitted because it is substantially the same as FIG.

FIG. 5 is a cross-sectional view of solenoid valve 260 of vane pump 200, showing a state in which the cross-sectional area of the flow path is the smallest. In the electromagnetic valve 260, the shaft 269 of the valve body 267 is formed by the inner peripheral surface of the first port 65h and the outer peripheral surface of the shaft 269 instead of the first through hole 69d and the second through hole 69e (see FIGS. 3 and 4). defines the minimum cross-sectional area of the flow path.

Specifically, the shaft 269 is inserted into the first port 65h with a gap from the inner periphery of the first port 65h when the flow passage cross-sectional area of the solenoid valve 260 is minimized. Since no hole is formed in the shaft 269, the first port 65h and the second port 65j communicate through the inner peripheral surface of the first port 65h and the shaft 269. and the shaft 269 defines the minimum flow cross-sectional area of the solenoid valve 260 .

In addition, when the flow passage cross-sectional area of the solenoid valve 260 is minimized, the base end 269f of the tapered portion 269c is positioned inside the first port 65h with a gap from the inner peripheral surface of the first port 65h. The outer diameter at the proximal end 269f is the maximum outer diameter of the shaft 269, and the area between the proximal end 369f and the inner peripheral surface of the first port 65h is the minimum channel cross-sectional area. Therefore, even if the position of the shaft 269 with respect to the plunger 68 or the position of the stepped portion 65e with respect to the first port 65h deviates from the desired position when the electromagnetic valve 260 is manufactured, the base end 269f of the tapered portion 269c is positioned within the first port 65h. As long as there is, the deviation can be tolerated. Therefore, the minimum cross-sectional area of the flow path of the solenoid valve 260 can be set with high accuracy, and variations in the minimum flow rate characteristics of the vane pump 200 can be reduced.

A groove 269g is formed in the outer circumference of the shaft 269 across the tapered portion 269c and the rear end 69b, and the first port 65h and the pressure chamber 64g communicate through the groove 269g. Therefore, the pressure in the first port 65h and the pressure in the pressure chamber 64g become substantially the same, and the suction force required to move the valve body 67 of the solenoid valve 60 can be reduced. Thereby, the coil 61 can be miniaturized, and the vane pump 200 can be miniaturized.

Similar to the first embodiment, the above embodiment has the following effects.

The vane pump 200 can set the minimum flow characteristic without providing a fixed orifice separate from the solenoid valve 260 . Therefore, the vane pump 200 can be miniaturized.

Further, by supplying the coil 61 with a current greater than or equal to a predetermined value, the flow passage cross-sectional area of the solenoid valve 260 is minimized. Therefore, the minimum flow characteristic of the vane pump 200 can be set without controlling the magnitude of the current supplied to the coil 61 with high accuracy.

<Third embodiment>
Next, a variable displacement vane pump 300 (hereinafter also simply referred to as "vane pump 300") according to a third embodiment will be described with reference to FIG. In the following, points different from the first and second embodiments will be mainly described, and configurations that are the same as or corresponding to the configurations described in the first and second embodiments will be indicated in the drawings in the first and second embodiments. The same reference numerals as those of the form are attached, and the description thereof is omitted. Also, since the configuration diagram of the vane pump 300 is substantially the same as that of FIG. 1, it is omitted.

FIG. 6 is a cross-sectional view of solenoid valve 360 of vane pump 300, showing a state in which the cross-sectional area of the flow path is the smallest. In the electromagnetic valve 360, instead of the first through-hole 69d and the second through-hole 69e (see FIGS. 3 and 4), the gap between the opening edge of the first port 65h and the tapered portion 369c of the shaft 369 allows the minimum flow. Road cross-sectional area is specified.

Further, a groove 369g is formed in the outer circumference of the shaft 369 of the valve body 367 across the tapered portion 369c and the rear end 69b, and the first port 65h and the pressure chamber 64g communicate through the groove 369g. Therefore, the pressure in the first port 65h and the pressure in the pressure chamber 64g become substantially the same, and the suction force required to move the valve body 67 of the solenoid valve 60 can be reduced. Thereby, the coil 61 can be miniaturized, and the vane pump 300 can be miniaturized.

Similar to the first and second embodiments, the above embodiment has the following effects.

The vane pump 300 can set the minimum flow characteristic without providing a fixed orifice separate from the solenoid valve 360 . Therefore, vane pump 300 can be miniaturized.

Further, by supplying the coil 61 with a current greater than or equal to a predetermined value, the cross-sectional area of the flow path of the solenoid valve 360 is minimized. Therefore, the minimum flow characteristic of the vane pump 300 can be set without controlling the magnitude of the current supplied to the coil 61 with high accuracy.

Hereinafter, the configuration, action, and effect of the embodiment of this configuration will be collectively described.

In this embodiment, the variable displacement vane pumps 100, 200, and 300 include a rotor 10 that is rotationally driven, a plurality of vanes 20 that are radially reciprocally movable with respect to the rotor 10, and vanes 20 that rotate as the rotor 10 rotates. The cam ring 30 has an inner peripheral surface 31 on which the tip portion 21 of the vane 20 slides, and is provided eccentrically with respect to the rotor 10 , and the pump chamber 30 a defined by the adjacent vane 20 and cam ring 30 . solenoid valves 60, 260, and 360 provided in the discharge passage 3b and having flow passage cross-sectional areas that change according to the supplied current; and a control valve 50 for controlling the amount of eccentricity of the cam ring 30 according to the pressure difference before and after the solenoid valves 60, 260, 360. The solenoid valves 60, 260, 360 operate in the discharge passage 3b when the passage cross-sectional area is the minimum. Allow oil flow.

In this configuration, the solenoid valves 60, 260, 360 function as fixed orifices having a predetermined flow cross-sectional area when the flow cross-sectional area is at its minimum. Therefore, the minimum flow characteristics of the variable displacement vane pumps 100, 200, 300 can be set without providing a fixed orifice separately from the solenoid valves 60, 260, 360. Thereby, the variable displacement vane pumps 100, 200, 300 can be miniaturized.

In addition, in this embodiment, the solenoid valves 60, 260, 360 are housed in a housing 63 having a first port 65h and a second port 65j respectively connected upstream and downstream in the discharge passage 3b, and supplied. valve bodies 67, 267, 367 that move according to the applied current to change the flow channel cross-sectional area; and a stepped portion 65e that defines a state in which the cross-sectional area of the flow path is minimized by limiting the flow path.

In this configuration, the stepped portion 65e defines a state in which the cross-sectional area of the flow path is minimized. Therefore, the minimum flow characteristics of the variable displacement vane pumps 100, 200, 300 can be set without controlling the current supply amount with high accuracy.

Further, in this embodiment, the solenoid valve 60 has a pressure chamber 64g formed by the housing 63 and the valve body 67, and the valve body 67 penetrates in the axial direction to define the first port 65h and the pressure chamber 64g. A communicating first through hole 69d and a second through hole 69e penetrating between the inner peripheral surface of the first through hole 69d and the outer peripheral surface of the valve body 67 and communicating with the first through hole 69d and the second port 65j. , and the second through hole 69e defines the minimum cross-sectional area of the flow path.

With this configuration, the flow path resistance of the first through holes 69d can be reduced. Therefore, the force acting on the valve body 67 due to the pressure difference between the first port 65h and the pressure chamber 64g can be reduced while setting the minimum flow rate characteristic of the variable displacement vane pump 100 by the solenoid valve 60.

Further, in this embodiment, the valve body 267 is inserted into the first port 65h in a state in which movement is restricted by the stepped portion 65e, and the gap between the valve body 267 and the inner peripheral surface of the first port 65h minimizes the flow passage cross-sectional area. stipulate.

With this configuration, deviations in the position of the shaft 269 with respect to the plunger 68 and the position of the stepped portion 65e with respect to the first port 65h at the time of manufacturing the solenoid valve 260 can be allowed. Therefore, the minimum cross-sectional area of the flow path of the solenoid valve can be set with high accuracy, and variations in the minimum flow characteristic of the vane pump 200 can be reduced.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

In the above embodiment, hydraulic oil is used as the working fluid. Water or other liquids may be used as the working fluid instead of hydraulic oil.

In the above embodiment, the first port 65h is connected upstream in the discharge passage 3b, and the second port 65j is connected downstream in the discharge passage 3b. The second port 65j may be connected upstream in the discharge passage 3b, and the first port 65h may be connected downstream in the discharge passage 3b.

In the above-described embodiments, the solenoid valves 60, 260, 360 are configured so that the channel cross-sectional area is minimized at the time of maximum adsorption. Instead of the electromagnetic valves 60, 260, 360, electromagnetic valves that minimize the cross-sectional area of the flow path in the non-adhered state may be used.

3b... Discharge passage 10... Rotor 20... Vane 21... Tip portion 30a... Pump chamber 30... Cam ring 31... Inner peripheral surface 50... Control valves (eccentricity control valves) 60, 260, 360 Solenoid valves 63 Housings 64g Pressure chambers 65e Stepped portions (limiting portions) 65h Third 1 port (upstream port), 65j... 2nd port (downstream port), 67, 267, 367... valve element, 69d... first through hole, 69e... second through hole, 100, 200, 300 ... variable displacement vane pump

Claims (3)

A variable displacement vane pump,
a rotor driven to rotate;
a plurality of vanes provided so as to reciprocate in a radial direction with respect to the rotor;
a cam ring having an inner peripheral surface on which tip portions of the vanes slide as the rotor rotates, and provided eccentrically with respect to the rotor;
a discharge passage through which working fluid discharged from a pump chamber defined by the adjacent vanes and the cam ring is guided;
an electromagnetic valve provided in the discharge passage, the flow passage cross-sectional area of which changes according to the supplied current, and which allows the working fluid to flow in the discharge passage when the flow passage cross-sectional area is at a minimum ;
an eccentricity control valve that controls the eccentricity of the cam ring according to the pressure difference across the solenoid valve in the discharge passage,
The solenoid valve is
a housing having an upstream port and a downstream port respectively connected upstream and downstream in the discharge passage;
a valve body that is housed in the housing and moves according to the current supplied to the coil to reduce the cross-sectional area of the flow path;
a restricting portion provided in the housing for restricting movement of the valve body in a direction of decreasing the cross-sectional area of the flow path to define a state in which the cross-sectional area of the flow path is minimized;
The restricting portion is a stepped portion that restricts the movement of the valve body by coming into contact with the valve body when the valve body moves in the direction of decreasing the cross-sectional area of the flow path when current is supplied to the coil. A variable displacement vane pump characterized by: A variable displacement vane pump,
a rotor driven to rotate;
a plurality of vanes provided so as to reciprocate in a radial direction with respect to the rotor;
a cam ring having an inner peripheral surface on which tip portions of the vanes slide as the rotor rotates, and provided eccentrically with respect to the rotor;
a discharge passage through which working fluid discharged from a pump chamber defined by the adjacent vanes and the cam ring is guided;
an electromagnetic valve provided in the discharge passage, the flow passage cross-sectional area of which changes according to the supplied current, and which allows the working fluid to flow in the discharge passage when the flow passage cross-sectional area is at a minimum;
an eccentricity control valve that controls the eccentricity of the cam ring according to the pressure difference across the solenoid valve in the discharge passage,
The solenoid valve is
a housing having an upstream port and a downstream port respectively connected upstream and downstream in the discharge passage;
a valve body that is housed in the housing and moves according to the current supplied to the coil to change the cross-sectional area of the flow path;
a pressure chamber formed by the housing and the valve body,
The valve body includes a first through hole that penetrates in the axial direction and communicates one of the upstream port and the downstream port with the pressure chamber, and an inner peripheral surface of the first through hole and an outer peripheral surface of the valve body. a second through hole penetrating therebetween and communicating with the first through hole and the other of the upstream port and the downstream port;
A variable displacement vane pump, wherein the second through-hole defines the minimum flow passage cross-sectional area. A variable displacement vane pump,
a rotor driven to rotate;
a plurality of vanes provided so as to reciprocate in a radial direction with respect to the rotor;
a cam ring having an inner peripheral surface on which tip portions of the vanes slide as the rotor rotates, and provided eccentrically with respect to the rotor;
a discharge passage through which working fluid discharged from a pump chamber defined by the adjacent vanes and the cam ring is guided;
an electromagnetic valve provided in the discharge passage, the flow passage cross-sectional area of which changes according to the supplied current, and which allows the working fluid to flow in the discharge passage when the flow passage cross-sectional area is at a minimum;
an eccentricity control valve that controls the eccentricity of the cam ring according to the pressure difference across the solenoid valve in the discharge passage,
The solenoid valve is
a housing having an upstream port and a downstream port respectively connected upstream and downstream in the discharge passage;
a valve body that is housed in the housing and moves according to the current supplied to the coil to change the cross-sectional area of the flow path;
a restricting portion provided in the housing for restricting movement of the valve body in a direction of decreasing the cross-sectional area of the flow path to define a state in which the cross-sectional area of the flow path is minimized;
The valve body has a shaft inserted into one of the upstream port and the downstream port in a state where movement is restricted by the restricting portion, and the outer peripheral surface of the shaft and the one port A variable displacement vane pump, wherein the minimum cross-sectional area of the flow path is defined by the distance from the inner peripheral surface of the variable displacement vane pump.

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