JPH0539784A - Variable capacity type vane pump device - Google Patents

Abstract

PURPOSE:To make the operating fluid led in to a suction chamber receive a supercharging effect even in case that a specific pump chamber is stopping its pumping function by the circulation of the operating fluid. CONSTITUTION:Suction ports 41 and 41' are provided to side plates 3 and 4 and near the circumferential end of a cam ring 5. A suction chamber 28 is provided to the side plates 3 and 4 and at the outer circumference of the cam ring 5 to link to the suction ports 41 and 41'. A suction-side passage 21 to connect between the suction chamber 28 and a cylinder chamber 13 in a change- over valve housing 12 is provided. A suction passage 8 to suck an operating fluid from a reservoir, and a bypass passage 29 to bypass-circulate a part of the discharge fluid are opened to communicate crossing, at the intermediate positions of the passage 21. When a specific pump chamber is in the condition to circulate the operating fluid, the operating fluid led in to the suction chamber 28 receives two times of supercharging functions. Consequently, the generation of a cavity resulting from a suction shortage can be prevented, and a pulsation phenomenon and the like can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement vane pump, and more particularly to a hydraulic pump device suitable for supplying a working fluid to a vehicle power steering device.

[0002]

2. Description of the Related Art In a hydraulic pump device used in a power steering apparatus for an automobile, the discharge flow rate of the pump is set so that a sufficient steering force can be assisted even at low speed running (generally when the engine speed is low). Has been done. Therefore, in such a hydraulic pump device, the hydraulic fluid having a flow rate proportional to the engine speed is discharged as the engine speed (engine speed) increases. This means that the flow rate of hydraulic oil becomes excessive during high-speed traveling (generally, when the engine speed is high), where steering force assistance is essentially unnecessary. To deal with this phenomenon,
A flow control valve system is widely used in which part of the hydraulic oil discharged from the pump (discharging oil) is not sent to the power assist unit of the power steering system, but instead bypassed to the hydraulic pump. Has been.

However, in this flow rate control valve system, high-pressure discharge oil discharged from the hydraulic pump is guided to the flow rate control valve, discharged from there to a bypass passage, and then returned to the suction port side. Therefore, when the engine is rotating at high speed, energy is consumed according to the engine rotation speed (rotation speed).
That is, in the bypass recirculation system using the flow control valve, energy loss (loss) due to bypass recirculation is performed when steering power assistance is hardly needed during high-speed traveling, etc., and this leads to deterioration of vehicle fuel consumption. There is a problem. Therefore, as a means for reducing the energy loss when such steering force assistance is not required, a method using a switching valve has been conventionally adopted.

As shown in FIG. 3, this is basically a variable displacement vane pump device composed of a vane pump with a flow control valve 26 and a switching valve 1. That is, the vane pump is housed in the housing 2 and driven to rotate, the vane 7, the outside of the vane 7, the cam ring 5 that contributes to the formation of the pump chamber, the rotor 6, the vane 7, and the side surfaces of the cam ring 5. Side plate 3, which contributes to the formation of the pump chamber,
4, a plurality of suction ports 41 and 41 'provided on the circumference of the side plates 3 and 4, a discharge port 31 provided to the side plate 3, and a specific discharge port 31 provided to the side plate 4. ', Etc., and further has a pressure chamber 27 connected to the discharge port 31 and a flow control valve 26 so as to be connected to the pressure chamber 27, and excess hydraulic oil from the flow control valve 26. Has a bypass path 29 for bypassing and recirculating to the suction side, and the suction path 8 is intersected with the bypass path 29 to exert a supercharge function, and the suction port 4 is provided on the downstream side thereof.
It is configured to have a suction chamber 28 connected to 1, 41 '.

Further, the switching valve 1 has a spool 11 and a spring 15 built in a switching valve housing 12, and a switching valve pressure chamber 14 communicating with the pressure chamber 27 is provided on one head side of the spool 11. A switching valve suction chamber 16 communicating with the suction chamber 28 is provided on the other head side. Various passages are provided between the vane pump and the switching valve 1. That is, the suction chamber 2
8 and the switching valve housing 12 between the suction side passage 22
However, a communication passage 23 is provided between the specific discharge port 31 ′ and the switching valve housing 12.
Further, the discharge side passage 24 is branched from the middle of the communication passage 23, is provided so as to be connected to the pressure chamber 27, and a check valve 241 is provided at an intermediate portion thereof. It is a thing. By adopting these configurations, when the power assist unit does not assist the steering force and requires only a small amount of hydraulic oil, the intake hydraulic oil is circulated in a part of the vane pump chamber to circulate that part. When the large amount of hydraulic oil is required, the function of the pump chamber that had been stopped will be restored to allow sufficient power assist while stopping the pump function of the above to reduce energy loss. It is a thing.

[0006]

By the way, by operating the switching valve 1, the function of a specific pump chamber is stopped,
Alternatively, in a system in which the pump discharge capacity is varied by reactivating the pump, when a specific pump chamber is not functioning, that is, when hydraulic oil is simply circulated, a bypass recirculation is performed in the bypass passage 29. Since the flow rate of the hydraulic oil that is used is reduced, the supercharge function is reduced. This also applies to a so-called suction side communication system in which the working oil discharged from a specific discharge port 31 'is directly returned to the suction chamber 28 side so as to circulate the working oil, as shown in FIG. Since the function is deteriorated, the amount of hydraulic oil sucked from the suction passage 8 becomes insufficient, which may cause cavitation in the pump chamber. Further, in the case of the suction side communication system, among the circulating hydraulic oil discharged from the specific discharge port 31 ′ and returned to the suction chamber 28, and the discharge oil discharged from the first discharge port 31 The new working oil that is sucked from the suction passage 8 under the supercharge effect by the return oil that is bypassed and recirculated by the flow control valve 26 of
However, there is a problem that interference occurs in the suction chamber 28, the flow of suction oil in the suction chamber 28 is disturbed, and shortage of suction from the suction port occurs. Further, the flow control valve 26
If the rotation speed is low and bypass recirculation is not performed, the supercharge effect may not be exerted and inhalation may be insufficient. It is an object (problem) of the present invention to provide a variable displacement vane pump device that eliminates such a half-charge phenomenon of the supercharge effect and exhibits a sufficient supercharge function during the circulation of the intake hydraulic oil. is there.

[0007]

In order to solve the above-mentioned problems, in the present invention, a rotor housed in a housing and driven to rotate, a vane that slides in a slit of the rotor, and the vane. A cam ring on the outer side of the rotor to form a pump chamber with the rotor, vane, etc., a plurality of side plates on both sides of the rotor, vane, and cam ring that contribute to the formation of the pump chamber; A discharge flow rate of discharge oil (working oil) discharged from a vane pump including a plurality of discharge ports, a plurality of suction ports and the like provided on the circumference of the side plate, and a pressure chamber connected to each discharge port is predetermined. Oil that consists of a flow control valve that bypasses the excess discharge oil to the bypass passage connected to the suction port when it exceeds the value A pump device having a suction side passage communicating with the suction port, a communication passage communicating with a specific one of the discharge ports, and a discharge side passage branching from the middle of the communication passage and communicating with the pressure chamber. ,
A variable displacement vane pump having a check valve in the middle of the discharge side passage, and further including a switching valve for switching the suction side passage to communicate with the communication passage when the pressure in the pressure chamber is low. In the device, an inlet passage for sucking hydraulic oil from the reservoir and a bypass passage for bypassing a part of the discharge oil from the flow rate control valve are opened in the inlet passage so as to cross-communicate. We decided to adopt the following configuration.

[0008]

According to the present invention, when the vane pump starts operating, the working oil sucked from the suction passage 8 (see FIG. 1) in FIG.
It is guided to the suction chamber 28 via the bypass 29. A part of the hydraulic oil guided to the suction chamber 28 is sucked from the first suction port 41, boosted in the pump chamber and discharged from the first discharge port 31 to the pressure chamber 27, and then by the flow control valve 26. It is sent to a power assist unit (not shown) of the power steering apparatus under the flow rate control.

By the way, in a state where the power assist section is not assisting the steering force (power assist),
The hydraulic pressure (load pressure) of the power assist section is low, and therefore the pressure of the pressure chamber 27 is also low. As a result, the pressure of the switching valve pressure chamber 14 in the switching valve 1 is low, and the spool 11 is pushed to the right by the action of the spring force of the spring 15 and placed in the state shown by the solid line in FIG. .. Therefore, the suction-side passage 22 and the communication passage 23 are in communication with each other, and the second discharge port 4 which is a specific discharge port.
The discharge oil discharged from 5 discharges the discharge chamber 27 ′, the communication passage 23,
It is sucked into the second suction port 41 ′ via the suction side passage 22 and the suction chamber 28. That is, in the pump chamber formed by the second suction port 41 ′ and the second discharge port 45, the suction working oil simply circulates.

In this case, the hydraulic oil sent from the switching valve 1 to the suction side passage 22 is the suction passage 8 as shown in FIG.
The first stage supercharge effect is exhibited when inhaling hydraulic oil from. Further, the suction working oil thus sucked is subjected to the second-stage supercharge action by the discharge oil that is bypass-recirculated at the bypass passage 29. That is, in the present invention, when the specific pump chamber circulates the hydraulic oil, the hydraulic oil introduced into the suction chamber 28 of the pump undergoes a supercharge action twice, and the suction hydraulic oil at this time is more Cavitation is further prevented from being generated due to the supercharge effect.

On the other hand, the load pressure increases and the pressure chamber 2
When the pressure of 7 becomes high, the pressure of the switching valve pressure chamber 14 also rises, so the spool 11 moves to the left against the spring force of the spring 15 and moves to the position shown by the chain double-dashed line in FIG. come. As a result, the hydraulic oil (discharged oil) discharged from the second discharge port 45 flows toward the discharge side passage 24 side as shown by the solid line arrow, where the check valve 241 is opened and flows out to the pressure chamber 27. That is, the second suction port 4
1 ', the specific pump chamber formed by the second discharge port 45 also exhibits the pump function, and the amount of hydraulic oil (discharge oil) sent to the power assist unit is increased. In this case, since there is no circulating hydraulic oil from the switching valve 1, the supercharge effect is exerted only by the bypass recirculation at the bypass 29 as in the conventional case.

[0012]

Embodiments of the present invention will be described with reference to FIGS. As shown in FIG. 2, the configuration of the present embodiment includes a vane pump including a rotor, vanes, cam rings, and the like.
It is basically a variable displacement vane pump device composed of a switching valve including a spool and a spring. In such a basic configuration, the vane pump is a conventionally known one, and the rotor 6 is housed in the housing 2 and driven to rotate, the vane 7 that slides in the slit of the rotor 6, the vane. 7, a cam ring 5 that forms a pump chamber with the rotor 6, vanes 7 and the like outside the rotor 7, side plates 3 and 4 on the side surfaces of the rotor 6, the vanes 7, and the cam ring 5 that contribute to the formation of the pump chamber, the side A hydraulic pump device including a plurality of discharge ports 31, 45 provided in each of the plates 3, 4 and a plurality of suction ports 41, 41 'provided near the circumferential ends of the side plates 3, 4 and the cam ring 5 and the like. In addition to these, a pressure chamber 27 connected to the discharge port 31 and the like is provided, and a flow control valve 26 is provided so as to be connected to the pressure chamber 27. In addition, there is a bypass passage 29 for bypassing the excess hydraulic oil from the flow control valve 26 to the suction side, and the bypass passage 29 is provided.
On the downstream side of the suction port 41, as shown in FIG.
It is configured to have a ring-shaped suction chamber 28 connected to 41 '.

Further, the switching valve 1 includes a switching valve housing 12
It has a cylinder chamber 13 therein, and the spool 11 and the spring 15 are basically built in the cylinder chamber 13. In addition to these, the pressure chamber 27 is provided on one head side of the spool 11. A switching valve pressure chamber 14 communicating with the pressure introducing passage 25 is provided, and a spring 15 for applying a spring reaction force to the spool 11 is provided on the other head side.
Is provided.

Further, various passages are provided between the vane pump and the switching valve 1. That is, as shown in FIG. 2, the side plate 4 of the vane pump is provided with the second discharge port 45.
A discharge chamber 27 'for accumulating hydraulic oil (discharge oil) discharged from the discharge port 45 is provided in the opening of the second discharge port 45, and the communication passage 23 is connected to the discharge chamber 27'. Is provided. A discharge side passage 24 is branched from the middle of the communication passage 23, is connected to the pressure chamber 27, and has a check valve 241 in an intermediate portion thereof.
Further, as shown in FIG. 1, a ring-shaped suction chamber 28 is provided on the outer peripheral portion of the cam ring 5, and the suction ports 41, 41 ′ are provided near the side plates 3, 4 and the circumferential end of the cam ring 5. Is provided, and the ring-shaped suction chamber 28 is provided.
It is connected to. Further, in the middle portion of the suction-side passage 22 that connects the cylinder chamber 13 of the switching valve 1 and the suction chamber 28, first, the suction-side passage 22 is connected to the suction-side passage 22 so that the suction passage 8 cross-communicates. Open, then
The bypass 29 is also opened so as to communicate with each other.

The operation state of this embodiment having the above-mentioned structure will be described. When the vane pump starts operating, for example, in FIGS. 1 and 2, the hydraulic oil sucked from the suction passage 8 is guided to the suction chamber 28 via the bypass passage 29. A part of the hydraulic oil guided to the suction chamber 28 is sucked from the first suction port 41, boosted in the pump chamber and discharged from the first discharge port 31 to the pressure chamber 27, and then by the flow control valve 26. It is sent to a power assist unit (not shown) of the power steering apparatus under the flow rate control.

By the way, when the power assist section is not performing steering force assistance (power assist),
The hydraulic pressure (load pressure) of the power assist section is low, and therefore the pressure of the pressure chamber 27 in which the load pressure of the power assist section is propagated is also low. As a result, the pressure introduced from the pressure introducing passage 25 is also low, so that the pressure in the switching valve pressure chamber 14 in the switching valve 1 is low. Therefore, the spool 11 is pushed to the right by the action of the spring force of the spring 15 and placed in the state shown by the solid line in FIG. As a result, the suction-side passage 22 that communicates with the suction chamber 28 and the communication passage 23 that communicates with the discharge chamber 27 'are in communication with each other.

Therefore, the discharge oil discharged from the second discharge port 45, which is a specific discharge port, is discharged from the discharge chamber 27 ',
It is sucked into the second suction port 41 ′ via the communication passage 23, the cylinder chamber 13, the suction side passage 22, and the suction chamber 28. That is, in the pump chamber formed by the second suction port 41 ′ and the second discharge port 45, the suction working oil simply circulates and does not act as a pump. As a result, the energy consumption generated by the pump function is reduced. Furthermore, in this case, FIG.
As shown in FIG. 4, the circulating hydraulic oil sent from the switching valve 1 to the suction side passage 22 sucks the suction hydraulic oil from the suction passage 8 at the intersection with the suction passage 8 by the supercharge effect and then the next bypass passage 29. Lead to. Next, the suction hydraulic fluid guided to the bypass passage 29 causes the hydraulic fluid that has been bypass-refluxed here to be sucked again by the supercharge action. In this way, the hydraulic oil introduced into the suction chamber 28 when the specific pump chamber is in the state of circulating the hydraulic oil is subjected to the supercharge effect of two times, and the suction amount is sufficiently increased. It has been secured. Therefore, cavitation does not occur in the hydraulic oil in this case, and noise and pulsation are prevented.

On the other hand, the load pressure increases and the pressure chamber 2
When the pressure of 7 becomes high, the switching valve pressure chamber 1
Since the pressure of 4 also rises, the spool 11 uses the spring 1
It moves to the left against the spring force of 5 and comes to the position shown by the chain double-dashed line in FIG. As a result, the communication passage 23 and the suction side passage 2
2 is cut off by the land portion 111 of the spool 11, and the hydraulic oil (discharge oil) discharged from the second discharge port 45 flows to the discharge side passage 24 side as shown by the solid line arrow, and here the check valve 241 is opened and it flows out into the pressure chamber 27. That is, the specific pump chamber formed by the second suction port 41 'and the second discharge port 45 also exhibits the pump function, and the amount of hydraulic oil (discharge oil) sent to the power assist unit is increased. In this case, since the circulating hydraulic oil from the switching valve 1 is lost, the supercharge effect due to this is not obtained, but the supercharge effect due to the bypass recirculation at the bypass passage 29 is exhibited.

[0019]

According to the present invention, in a vane pump having a plurality of sets of intake ports and discharge ports, when the load pressure of the power steering device power assist portion is low, the specific intake port and discharge port In the variable displacement vane pump device having a switching valve for stopping the pump function by simply circulating the hydraulic oil through the port and for restoring the pump function of the stopped portion when the load pressure increases, A suction passage for connecting the suction chamber and the cylinder chamber in the switching valve housing to a suction passage for sucking the working oil from the reservoir and a part of the discharge oil from the flow control valve for bypass circulation. Since the bypass passages are provided so as to communicate with each other, when the specified pump chamber is in a state where the pump function is stopped by the hydraulic oil circulation, The first stage Yaji effect, second stage and 2
As a result, the amount of oil sucked from the suction passage 8 is sufficiently secured, and the cavitation of the hydraulic oil sucked into the suction chamber is sufficiently removed by the influence of the supercharge effect twice. It becomes a state. In this way, problems such as a shortage of pump suction hydraulic oil have been resolved, and it has become possible to prevent the occurrence of pulsation phenomenon and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a vane pump, a switching valve and the like according to the present invention.

FIG. 2 is a vertical sectional view showing the structure of a vane pump, a switching valve and the like according to the present invention.

FIG. 3 is a vertical cross-sectional view showing a structure of a vane pump, a switching valve and the like having a switching function by a suction side communication system in a conventional example.

[Explanation of symbols]

 1 Switching Valve 11 Spool 12 Switching Valve Housing 13 Cylinder Chamber 14 Switching Valve Pressure Chamber 15 Spring 2 Housing 22 Suction Side Passage 23 Communication Passage 24 Discharge Side Passage 241 Check Valve 25 Pressure Introduction Passage 26 Flow Control Valve 27 Pressure Chamber 27 'Discharge Chamber 28 suction chamber 29 bypass passage 3 side plate 31 first discharge port 4 side plate 41 first suction port 41 'second suction port 45 second discharge port 5 cam ring 6 rotor 7 vane 8 suction passage

Claims (1)

[Claims] 1. A rotor housed in a housing and driven to rotate, a vane that slides in a slit of the rotor, a cam ring outside the vane that forms a pump chamber with the rotor, the vane, and the like. A plurality of side plates on both sides of the rotor, vane, and cam ring that contribute to the formation of the pump chamber, a plurality of discharge ports provided on each side plate, and a plurality of side plates provided on the circumference of the side plate. When the discharge flow rate of the discharge oil delivered from the vane pump composed of the suction port of the above and the pressure chambers connected to the discharge ports exceeds a predetermined value, the surplus discharge oil is bypassed to the bypass passage connected to the suction port. A vane pump device comprising a flow control valve for recirculation, the suction side passage communicating with the suction port, and the discharge port. A communication passage communicating with a specific port of the discharge port, a discharge side passage branched from the middle of the communication passage and communicating with the pressure chamber, and a check valve in the middle of the discharge side passage. In a variable displacement vane pump device including a switching valve that switches so that the suction side passage communicates with the communication passage when the pressure in the pressure chamber is low, the suction side passage has a suction valve for sucking hydraulic oil from a reservoir. A variable displacement vane pump device characterized in that an intake passage and a bypass passage for bypassing a part of the oil discharged from the flow rate control valve for bypass circulation are provided so as to cross-communicate with each other.