JPH0526956B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable displacement pump, and is effective for use as a hydraulic pump for assisting steering force in automobiles, for example.

[Prior art]

Conventionally, regarding the flow rate control of this type of pump, a method has been adopted for automobiles in which the oil once discharged is returned to the suction side of the pump via a flow rate regulating valve. However, this type of pump wastes the power of the pump, so various studies are being conducted to control the capacity of the pump itself to reduce the power consumed in rotating the pump. Many examples of the above-mentioned capacity limitations relate to so-called variable capacity vane pumps of the type shown in Japanese Patent Application Laid-Open No. 58-47192. This attempts to control the capacity by continuously changing the amount of eccentricity between the cam and rotor of the vane pump by shifting the outer cam ring of the vane pump, which has one working chamber. However, when this type of pump is applied to automobiles, it has the disadvantages that the pump is large and has a complicated structure, and that the response for moving the cam is poor, so it has not been put into practical use yet.

In contrast, the present invention attempts to change the capacity of a vane pump having a plurality of working chambers by controlling the number of working chambers that operate as a pump. Similar to this type of thinking, there is a collection of lectures from the Society of Automotive Engineers of Japan.
831019 has been proposed, which has a plurality of cam rotors and is intended to reduce the operation as a pump if necessary. However, as is easily understood, this pump has the disadvantage of being structurally more complex than conventionally used hydraulic pumps.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to provide a vane type pump in which a plurality of pump working chambers are formed, and to adjust the number of working pump working chambers as necessary. By controlling and changing the discharge amount from the pump, the power consumption of the pump is reduced.

〔Example〕

The configuration of a first embodiment of the present invention will be described using FIGS. 1 and 2. FIG. 1 is a longitudinal cross-sectional view of this embodiment, and FIG. 2 is a cross-sectional view taken from FIG. 1.

Reference numeral 3 denotes a rotor that rotates under the driving force of an engine (not shown). It consists of A cylinder 2 having a substantially triangular inner peripheral surface 2g is fitted into the outer periphery of the roller body 3a, and a front plate 19 is provided on the front end surface of the rotor body 3a and the cylinder 2, and a rear plate 20 is provided on the rear end surface. However, each rotor body 3a
and the cylinder 2 is placed between them. Front plate 19, cylinder 2, rear plate 2
0 is fixed by a pin 21. Since the inner peripheral surface 2g of the cylinder 2 has a substantially triangular shape, the rotor body 3a and the cylinder 2 form crescent-shaped spaces 18a, 18b, and 18c.

Furthermore, the housing 1 is wrapped around the rotor main body 3a, cylinder 2, and front plate 19.
will be placed. The housing 1 is mutually fixed to the rear plate 20 with bolts 22. The front shaft portion 3b passes through the front plate 19 and is connected to the boss portion 1 of the housing 1.
A is rotatably supported via a shaft sealing device 23. On the other hand, the rear shaft portion 3c is fitted into the recess 20a of the rear plate 20 and rotatably supported.

A plurality of vane grooves 3d opening in the radial direction are provided on the outer periphery of the rotor main body 3a, and a vane groove 4 is slidably inserted into each vane groove 3d. The vanes 4, the outer circumference of the rotor body 3a, and the inner circumferential surface 2g of the cylinder 2 define the crescent-shaped spaces 18a, 18b, and 18c, that is, the pump operating chamber P. The cam ring 2 is formed with a suction port 2a for sucking hydraulic oil into the crescent-shaped space 18a and a discharge port 2b for discharging the hydraulic oil from the space 18a. Similarly, a suction port 2c for sucking hydraulic oil into the crescent-shaped space 18b and this space 18b.
A discharge port 2d for discharging hydraulic oil from the cam ring 2 is formed in the cam ring 2. A suction port 2e for sucking hydraulic oil into the crescent-shaped space 18c and a discharge port 2f for discharging hydraulic oil from this space 18c are formed in the cam ring 2.

The housing 1 is provided with a suction passage 5 communicating with the suction port 2a and a discharge passage 6 communicating with the discharge port 2b. Further, this housing 1 is provided with two spool holes 12 and 13. A communication hole 7 for communicating the spool hole 12 with the suction port 2c, a communication hole 8 for communicating the spool hole 12 with the discharge port 2d, and a communication hole 3 for communicating the spool hole 12 with the outside of the housing. Communication holes 24, 2
5 and 26 are provided in the housing 1, respectively. The other housing 1, that is, the housing 1 on the side where the spool hole 13 is formed, includes a communication hole 9 for communicating with the suction port 2e, a communication article 10 for communicating with the discharge port 2f,
and three communication holes 27, 2 with the outside of the housing.
8 and 29 are provided. Said spool hole 1
A spool 30 and a spring 31 that biases the spool 30 are inserted into the spool hole 13, and a spool 32 and a spring 33 that biases the spool 32 are inserted into the spool hole 13. Here, the set load of the spring 33 is higher than that of the spring 31.

A communication hole 30a is provided in the center of the spool 30. Further, grooves 30b and 30c are formed on the circumference of the spool 30 at two locations. The communication hole 30a communicates the pressure chamber 17 formed at one end of the spool 30 with the groove 30b. Similarly, the spool 32 is also formed with a communication hole 32a and grooves 32b, 32c.

A suction pipe 3 is provided in the suction passage 5 of the housing 1.
This suction pipe 34 and the communication holes 24 and 26 are connected by pipes 36 and 39, respectively. Further, a discharge pipe 35 having a throttle 15 disposed in the middle thereof is connected to the discharge passage 6. The communication holes 26 and 29 are provided on the upstream side of the throttle 15 of the discharge pipe 35, that is, on the side closer to the pump.
Pipes 38 and 41 are connected thereto. Pipes 37 and 40 connecting the communication holes 25 and 28 and the discharge pipe 35 are connected to the discharge pipe 35 on the downstream side of the throttle 15, that is, on the opposite side of the pump from the throttle 15.

First, the operation of an oil pump in general will be explained.

When the front shaft portion 3b of the rotor 3 receives a driving force from an engine (not shown), the driving force causes the rotor main body 3a to rotate inside the cylinder 2 clockwise (in the direction of the arrow) in FIG. Then, the vane 4 inserted into the vane groove 3d of the rotor body 3a protrudes in the centrifugal direction due to centrifugal force. now,
Let's focus on one vane 4a and the vane 4b located immediately behind it. The front vane 4a projects into the crescent-shaped space 18, and then the vane 4a slides on the inner peripheral surface 2a of the cylinder 2 as the rotor 3 rotates. Then, vane 4a and the next vane 4b
The volume of the pump working chamber P formed by the above gradually increases, and hydraulic oil is sucked through the respective suction ports 2a, 2c, and 2e provided in the cam ring 2. Thereafter, the rotor 3 rotates, and as the volume of the pump working chamber P gradually decreases, hydraulic oil is discharged from each discharge port 2b, 2d, 2f provided in the cam ring 2. These suction and discharge processes are repeated for each vane in sequence, and the pump as a whole performs pumping work.

Next, the operation of this embodiment will be explained.

When the above-mentioned pump work is performed as the rotor 3 rotates, the hydraulic oil discharged from the pump working chamber P flows into the discharge pipe 35. Due to this flow,
A pressure difference is generated between both ends of the throttle 15 provided in the discharge pipe 35, that is, between the upstream side and the downstream side. This differential pressure is transmitted to the pressure chambers 16 and 17 at both ends of the spool 30 in the spool hole 12 through the pipes 37, 38 and the communication hole 30a provided in the spool 30. Similarly, this pressure difference is caused by the piping 40,
41 and the communication hole 32a provided in the spool 32
The pressure is also transmitted to the pressure chambers 42 and 43 at both ends of the spool 32 in the spool hole 13.

First, in Fig. 3, the pump rotation speed is A.
I will explain when it is less than .

When the pump rotation speed is less than A, the force in the upper part of FIG. This is smaller than the resultant force of the downward force in FIG. 1 and the set load of the spring 31. The pressure transmitted to the pressure chamber 42 causes a force acting on the spool 32 downward in FIG. 1, and the pressure transmitted to the pressure chamber 43 causes a force acting on the spool 32 upward in FIG. This is when the force is smaller than the force added with the set load of the spring 33. At this time, the position of the spool 30 in the spool hole 12 and the position of the spool 32 in the spool hole 13 are as shown in FIG. At this time, communication holes 7 and 24, communication holes 8 and 25, communication holes 9 and 27, and communication holes 10 and 28 are in communication with each other.

The operation of this pump when it is operated with the spool position as described above will be explained. Hydraulic oil is supplied to the pump working chamber 18a from the suction pipe 34, through the suction passage 5, and from the suction port 2a. Then, it is discharged from the discharge port 2b through the discharge passage 6 to the discharge pipe 35. Next, the pump working chamber 18
Hydraulic oil is supplied to b from the suction pipe 34 through the communication hole 24, the communication hole 7, and the suction port 2c via a pipe 36 connected to the suction pipe 34.
Then, from the discharge port 2d, the communication hole 8 and the communication hole 25
The hydraulic oil is discharged to the pipe 37 and the discharge pipe 35 through the pipe 37 and the discharge pipe 35. In addition, hydraulic oil is supplied to the pump working chamber 18c from the suction pipe 34 through a pipe 39 connected to the suction pipe 34, and from the communication hole 27, the communication hole 9, and the suction port 2e. Then, from the discharge port 2f, the pipe 4 passes through the communication hole 10 and the communication hole 28.
0, the hydraulic oil is discharged to the discharge pipe 35.

In other words, the pump work as a whole is performed in three chambers, pump working chambers 18a, 18b, and 18c, and the pump discharge flow rate is the solid line portion of the straight line represented by α in Fig. 3. .

Next, consider the case where the pump rotational speed is greater than or equal to A and less than B in FIG.

At this time, the force acting on the spool 30 in the upward direction in FIG. It is larger than the force acting downward in FIG. Then, a force acting downward in FIG. 1 on the spool 32 due to the pressure transmitted to the pressure chamber 42 is applied to the spool 32 due to the pressure transmitted to the pressure chamber 43 and the set load of the spring 33. This is when it is smaller than the force acting upward in Figure 1. At this time, the position of the spool 30 in the spool hole 12 and the position of the spool 32 in the spool hole 13 are as shown in FIG. In other words, the communication holes 25, 7, and 8 are in communication with each other, and the communication hole 24 is not in communication with any other communication hole. Also, the communication holes 9 and 27 and the communication holes 10 and 28 are in communication with each other.

The operation of this pump when it is operated with the spool position as described above will be explained. Hydraulic oil is supplied to the pump working chamber 18a from the suction pipe 34, through the suction passage 5, and from the suction port 2a. The hydraulic oil is then discharged from the discharge port 2b to the discharge pipe 35 via the discharge passage 6. Next, looking at the pump working chamber 18b, as described above, the communication holes 7, 8, and 25 are in communication with each other. Therefore, the flow rate of hydraulic oil supplied from the communication hole 7 via the suction port 2c is greater than the flow rate of the hydraulic oil supplied from the communication hole 7 through the suction port 2c.
is equal to the flow rate of hydraulic fluid discharged through In other words, the hydraulic oil discharged from the communication hole 8 is
Then, the pump working chamber 18 returns via the suction port 2c.
b. That is, the flow rate of the hydraulic oil flowing through the communication hole 25 is zero, and the flow rate of the hydraulic oil flowing through the communication hole 24 is zero.
are in a blocked state, so the pipes 36 and 37
The flow rate of hydraulic oil flowing through becomes zero. Therefore, the pump working chamber 18b is in an operating state in which there is no differential pressure between the suction pressure and the discharge pressure, and does not perform the work as a pump, that is, does not operate.

Further, hydraulic oil is supplied to the pump working chamber 18c from the suction pipe 34 through a pipe 39 connected to the suction pipe 34, the communication hole 27, the communication hole 9, and the suction port 2e. The hydraulic oil is then discharged from the discharge port 2f through the communication hole 10 and the communication hole 28 to the pipe 40 and the discharge pipe 35.

In other words, pumping work for the pump as a whole is performed in two chambers, pump working chambers 18a and 18c, and pump working chamber 18b does not perform any work as a pump. Therefore, the pump discharge flow rate is the solid line portion of the straight line represented by β in FIG.

Here, when the pump working chamber 18b does not operate as a pump, it is important that the pressure inside the working chamber 18b is at the pressure on the high pressure discharge side.

When the spool 30 is in the position shown in FIG. 4, the discharge port 2d and suction port 2c of the working chamber 18b are
They communicate through communication holes 7 and 8. At this time, it is possible to make the pressure in the working chamber 18b the suction pressure, but according to research by the present inventors, if it is made to communicate with the suction pressure, cavitation occurs near the suction port 2c. It was hot. Generally, when a pump sucks oil, the suction pressure tends to be below atmospheric pressure, and when this happens, the air in the oil expands and creates bubbles. This is cavitation, and when cavitation occurs, it increases the noise of the pump and causes damage to the vanes and cams. Particularly in the case of communicating the suction port and the discharge port of the working chamber as in the present invention, a big problem has arisen. In consideration of this, the inventors of the present application made extensive studies and decided to introduce pressure on the high pressure discharge side into the working chamber as shown in the present invention. Cavitation is generally less likely to occur when oil is inhaled under a certain pressure. When the suction port and the discharge port are communicated as shown in Fig. 4, the suctioned oil is sucked in from the discharge port as it is through the communication holes 7 and 8, so if there is no place where negative pressure occurs during the flow, it is necessary to Cavitation does not occur. However, due to the structure of the pump, especially near the suction port 7,
It was inevitable that the edges would hit or sharp bends would occur, and it was impossible to eliminate cavitation just by changing the shape. Therefore, it has been found that it is extremely effective to collapse the air bubbles in the oil in the working chamber and prevent cavitation by introducing the pressure on the high-pressure discharge side through the pipe 37 as shown in the present invention.

Next, in FIG. 3, the case when the pump rotation speed is equal to or higher than B will be explained.

When the pump rotation speed is B or higher, the differential pressure generated before and after the throttle 15 will be equal to the pump rotation speed A as described above.
Since the spool 30 in the spool hole 12 becomes larger than when it is greater than or equal to B and less than B, the spool 30 in the spool hole 12 is
It is in the same position as in the case of . Further, the force acting downwardly on the spool 32 in FIG. It is larger than the force acting upward in Figure 1. At this time, the position of the spool 30 in the spool hole 12 and the spool 32 in the spool hole 13 are
The position is as shown in FIG. 5, and the communication holes 25, 7, and 8 are in communication with each other, and the communication hole 24 is not in communication with any other communication hole. Further, the communication hole 27 in which the communication holes 9, 10, and 40 communicate with each other does not communicate with any other communication holes.

The operation of this pump when it is operated with the spool position as described above will be explained. Hydraulic oil is supplied to the pump working chamber 18a from the suction pipe 34, through the suction passage 5, and from the suction port 2a. The hydraulic oil is then discharged from the discharge port 2b to the discharge pipe 35 via the discharge passage 6. Next, looking at the pump working chamber 18b, the position of the spool 30 within the spool 12 is the same as when the pump rotation speed is greater than or equal to A and less than B, and the flow path of the hydraulic oil is also the same. Therefore, the flow rate of the hydraulic oil flowing through the pipes 36 and 37 is zero, and the pump working chamber 18b is in an operating state with no differential pressure between the suction pressure and the discharge pressure.
The pump working chamber 18b does not perform any work as a pump.

Further, the description will be made regarding the pump working chamber 18c.
As mentioned above, the communication holes 9, 19, and 40 are in communication with each other, and the suction port 2e is connected to the communication hole.
The flow rate of the hydraulic oil supplied through the discharge port 2
Since the flow rate of the hydraulic oil discharged from the communication hole 10 is equal to the flow rate of the hydraulic oil discharged from the communication hole 10 from the communication hole 9, the hydraulic oil discharged from the communication hole 9 is supplied to the pump working chamber 18c again through the suction port 2e. That is, since the flow rate of the hydraulic oil flowing through the communication hole 25 is zero and the communication hole 24 is in a closed state, the piping 3
The flow rate of the hydraulic oil flowing through 9 and 40 becomes zero.
Therefore, the pump working chamber 18c is in an operating state where there is no differential pressure between the suction pressure and the discharge pressure, and the pump working chamber 18c does not perform any work as a pump.

In other words, the pump work as a whole is performed only in the pump working chamber 18a, and the pump working chamber 1
8b and 18c do not perform any work as pumps. Therefore, the pump discharge flow rate is γ in Figure 3.
This is the solid line part of the straight line represented by . still,
In this case, high-pressure discharge-side hydraulic oil is introduced into the pump working chambers 18b and 18c, as described above.

By performing the above operations, the pump of this embodiment can sequentially change the number of pump working chambers from 3 → 2 → 1 as the rotation speed increases,
This has the technical effect of being able to reduce the driving energy while ensuring the required flow rate for the pump.

In addition, the pump working chamber can be changed from 3 to 2 or from 2 to 1.
The points at which the changes occur, i.e., points A and B in Figure 3.
The point is to ensure the required flow rate as a pump,
It goes without saying that the optimum value can be changed by changing the shape of the diaphragm 15 and the set loads of the springs 31 and 33.

In addition, in this embodiment, the hydraulic fluid on the high pressure discharge side is guided to the pump working chamber which is not in operation, i.e., is not doing work, but this is to prevent cavitation that occurs during high speed operation as described above. Figure 6 shows the effect. In Figure 6, δ
is the configuration of this embodiment, and ε is a configuration in which hydraulic fluid on the suction side is guided into the pump operating chamber when the pump is not in operation, without guiding hydraulic fluid on the high-speed discharge side. FIG. 6 shows the relationship between the rotational speed and the noise level for the pumps in the two configurations described above. Figure 6 shows measurements taken at a position 25 cm behind the pump under test conditions of a discharge pressure of 50 kg/cm ² and an oil temperature of 80°C. As can be seen from the figure, the pump δ according to this embodiment has a lower noise level, especially during high-speed operation, compared to the pump ε, which does not have a configuration in which hydraulic oil on the high-pressure discharge side is guided into the pump working chamber when the pump is not in operation. , it can be seen that it has a great effect.

Next, a second embodiment will be described.

In the first embodiment, the number of pump working chambers is changed from 3 to 2 to 1 as the rotational speed of the pump increases. However, if the pump operating constant does not need to be 2, , the pump operating constant is 3→
By creating a structure that changes from 1 to 1, it is possible to reduce the number of parts and achieve a reduction in size and weight.

Here, the configuration of this embodiment will be explained. 7th
In the figure, the housing 100 is provided with one spool hole 12, and the spool hole 12 has a communication hole 102 communicating with the suction port 2c, a communication hole 104 communicating with the discharge port 2d, and the housing 1
Communication holes 24 and 25 that communicate with the outside of 00 are provided. Further, the communication hole 102 is provided with a communication hole 103 that communicates with the outside of the housing 100, and the communication hole 104 is also provided with a communication hole 103 that communicates with the outside of the housing 100.
A communication hole 105 communicating with the outside is provided.
Further, the housing 100 is provided with a communication hole 106 that communicates between the suction port 2e and the outside of the housing 100, and a communication hole 106 that communicates between the suction port 2e and the outside of the housing 100.
A communication hole 107 communicating with the outside is provided. Here, the communication holes 103 and 106 are connected to the pipe 1
The communication holes 105 and 107 are connected by a pipe 109.

The operation of the second embodiment with the above configuration will be explained. If we consider the case when the pump rotation speed is less than C in FIG. 8, a certain pressure is transmitted to the pressure chambers 16 and 17 due to the differential pressure generated before and after the throttle 15. Here, the force acting upward in FIG. 7 on the spool 30 due to the pressure transmitted to the pressure chamber 16 is the pressure transmitted to the pressure chamber 17 and the force applied to the spring 1.
This is smaller than the force acting downward in FIG. 7 on the spool 30 due to the set load of 10. That is, the spool 30 in the spool hole 12 is in the position shown in FIG.

If this pump is operated under the above conditions,
As in the case where the pump rotation speed is less than A as described in the first embodiment of the present invention, the pump working chamber 18
Pumping work is performed in three rooms a, 18b, and 18c. The discharge flow rate of the pump at this time is the solid line portion of the straight line represented by α' in FIG.

Next, in FIG. 8, consider the case when the pump rotation speed is c or more. The force acting upward in FIG. 7 on the spool 30 due to the pressure transmitted to the pressure chamber 16 is due to the pressure transmitted to the pressure chamber 17 and the spring 1.
The set load of 10 is smaller than the force acting on the spool 30 downward in FIG. 7, and the spool 30 in the spool hole 12 moves to the position shown in FIG.

If this pump is operated under the above conditions,
In the first embodiment of the present invention, as in the case where the pump rotation speed is B or more, pump work is performed only in the pump working chamber 18a, and the pump working chambers 18b and 18c have a differential pressure between the suction pressure and the discharge pressure. It will be in a non-operational state. The discharge flow rate of the pump is the solid line portion of the straight line represented by β' in FIG.

By performing the above operation, the pump of this embodiment can change the number of working chambers of the pump from 3 to 1 as the rotation speed increases, reducing drive horsepower at high rotation speeds. This has the technical effect of making it possible. In this case, in this embodiment, high-pressure discharge-side hydraulic oil is introduced into the pump working chambers 18b and 18c.

Furthermore, when the number of pump working chambers does not need to be reduced to one, by changing the configuration of the second embodiment, the number of pump working chambers can be changed from 3 to 2 as the pump rotational speed increases. It can be easily inferred that similar operations are also possible.

Further, referring to FIG. 10, a third embodiment will be described. This embodiment uses a cylinder 200 having an inner peripheral surface 200a that forms two pump chambers on the circumference.
into the housing 201, and this cylinder 20
0, the rotor 3 and vane 4 define two pump working chambers 202a and 202b. Of these two pump working chambers 202a and 202b, the pump working chamber always performs a pumping action, and the pumping action is performed by switching the oil passage of the hydraulic oil introduced into the pump working chamber 202b by the spool 203. 2→
1. Here, in the pressure chamber 204 formed at one end of the spool 203,
A communication hole 205 is provided so that the pressure of the hydraulic oil discharged from the pump working chamber 202b is guided, and a discharge pipe 208 is provided in the pressure chamber 207 at the other end.
The pressure of the hydraulic oil after passing through the throttle 206 provided in the opening is introduced through the communication hole 203a.

The operation when the pump of this embodiment is operated with the above configuration will be explained. Pressure around a throttle 206 provided in a discharge pipe 208 is introduced into pressure chambers 204 and 207 formed at both ends of the spool 203, respectively. As the pump rotation speed increases, a load is applied to the spool 203 in the right direction in FIG. 10 due to the differential pressure generated before and after the throttle 206. Depending on the balance between this load and the set load of the spring 209, the spool 203 moves, and high-pressure discharge-side hydraulic oil is introduced into the pump working chamber 202b. At this time, it performs the same operation as the first embodiment of the present invention and has the same technical effects as the first embodiment of the present invention.

Furthermore, a fourth embodiment will be described. In the first, second, and third embodiments of the present invention described above, each pump working chamber has the same volume, but the discharge flow rate required when the number of pump working chambers performing pump action is the minimum is If the number of pumps is smaller, as shown in FIG.
a to the other pump working chambers 300b and 300
It shall be less than c. This has the effect that the driving force can be further reduced when the number of pump operation chambers that perform the pump action is minimized. In this example, the volume of each pump working chamber is 300c>
300b>300a, but this is 300b>300c>300a,
Alternatively, it is obvious that 300b=300c>300a may be used.

In each of the above-mentioned embodiments, the spool is moved by the internal pressure of the pump and the number of pump operating chambers is controlled. Naturally, it is possible to control the number of pump operating chambers using the actuator.

〔Effect of the invention〕

The present invention provides a vane type pump in which a plurality of pump working chambers are formed as described above, and is provided with a switching means for communicating the suction passage and the discharge passage of at least one pump working chamber, and the switching means is provided as necessary. By controlling the number of pump working chambers in operation, the amount of discharge from the pump as a whole is changed.
This has the effect that the power consumption of the pump can be reduced in accordance with the number of pump working chambers in operation. Furthermore, in the present invention, a part of the discharge side pressure of other operating pump operating chambers is guided to the pump operating chamber that is controlled not to operate by the switching means, so that the pressure generated therein is Another advantageous effect is that cavitation is prevented. This has the excellent effect of reducing the noise generated from the pump and allowing the pump to operate smoothly while controlling the capacity with high reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. 1, FIG. 3 is a diagram for explaining the first embodiment, 5 is a sectional view for explaining the operation of the first embodiment, FIG. 6 is a sectional view for explaining the first embodiment, FIG. 7 is a sectional view for explaining the second embodiment of the present invention, and FIG. 8 is a sectional view for explaining the operation of the first embodiment. , FIG. 9 is a diagram for explaining the second embodiment, and FIG. 10 is a diagram for explaining the third embodiment.
FIG. 11 is a sectional view showing the fourth embodiment. 2... Cylinder, 3... Rotor, 4... Vane, 2a, 5... Suction port forming a suction flow path, suction passage, 2c, 7, 24... Suction port forming a suction flow path, communication hole, suction Passage, 2e, 9, 27...
Suction port forming a suction flow path, suction passage, 2b, 6
...Discharge port forming a discharge flow path, discharge passage, 2
d, 8, 25...Discharge port forming a discharge flow path, communication hole, discharge passage, 2f, 10, 28...Discharge port forming a discharge flow path, communication hole, discharge passage, 18a,
18b, 18c...Space that is a plurality of pump operation chambers, 30, 32...Spool that is a switching means,
37, 40...Piping forming a flow path.

Claims (1)

[Scope of Claims] 1. A rotor that rotates in response to a driving force, a vane groove provided as an opening in the rotor, a vane slidably inserted into the vane groove, and a vane disposed on the outer periphery of the rotor. a cylinder having a non-circular inner peripheral surface that forms a plurality of pump working chambers by the rotor and the vanes; a plurality of suction passages that suck working fluid into the plurality of pump working chambers; a plurality of discharge passages for discharging working fluid from the plurality of pump working chambers; and a switching means for communicating at least one of the suction passage and one of the discharge passages, and the switching means allows the suction to be connected to the suction passage. At least one of the pump working chambers in which the flow path and the discharge flow path communicate with each other has a discharge side pressure of the other pump working chambers in which the suction flow path and the discharge flow path do not communicate with each other. A vane-type variable displacement pump, characterized in that the switching means is configured so that the flow path to which the suction side pressure of the other pump working chamber is guided is closed. 2. At least one of the pump working chambers has a volume different from that of the other pump working chambers.
Vane-type variable displacement pump as described in . 3. The vane type according to claim 2, wherein the pump operating chamber having the smallest volume among the pump operating chambers is configured to constantly communicate with the suction flow path and the discharge flow path, and to perform a pump action at all times. Variable displacement pump.