JPS60222579A - Vane type variable capacity pump - Google Patents

Abstract

PURPOSE:To reduce the consumption power of a pump by varying the discharge amount of the pump by selecting the number of operating chambers of the vane pump and the spool valves used. CONSTITUTION:The captioned vane pump has a noncircular cam ring 2, and has three operation chambers 18a, 18b, and 18c inside. Though into the operating chamber 18a, a suction passage 34 and a discharge passage 35 directly communicate, the communication to other operating chambers is performed through spool switching valves 30 and 32. Each spool switching valve is installed at one edge of a spool so as to shift by receiving the pilot pressure from the discharge passage, and when the discharge pressure increases, the operating chambers 18b and 18c are shurt-off from the suction and discharge passages, and the suction side and the discharge side of the operating chamber are short-circuited.

Description

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

[Prior art]

Conventionally, the flow control method for this type of pump is to return the discharged oil to the suction side of the pump via a flow rate adjustment valve.
is used for automobiles.

However, this type of pump wastes the power of the pump, so various studies are being conducted to reduce the power consumed in rotating the pump by controlling the capacity of the pump itself. An example of the above-mentioned capacity control is the type shown in Japanese Patent Laid-Open No. 58-47192.
Many of them are related to so-called variable displacement vane pumps.

This attempts to control the capacity by continuously changing the eccentricity of the cam and rotor of the vane pump by shifting the outer cam ring of the vane pump, which has two working chambers. However, when trying to use this type of pump for automobiles, it has the drawbacks of being large and having a complicated structure, and poor responsiveness for moving the cam, 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 kind of idea, as shown in Society of Automotive Engineers of Japan Proceedings 831B19, a system has been proposed that has multiple cam rotors and reduces pump operation as needed. ing. 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 compressor in which a plurality of pump working chambers are formed, in which a pump is operated in one of the pump working chambers. The power consumption of the pump is reduced by controlling the number of working chambers as necessary to change the amount of discharge from the pump.

〔Example〕

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

3 is a rotor that rotates under the driving force of an engine (not shown), and this rotor 3 has a cylindrical rotor body 3a.
and a front shaft portion 3b and a catcher shaft portion 3C provided on both end surfaces of the rotor body 3a. A cylinder 2 having a substantially triangular inner peripheral surface 2g is fitted into the outer periphery of the rotor 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 lever plate 20 is provided on the rear end surface. , are arranged so as to sandwich the rotor main body 3a and the cylinder 2, respectively. The front plate 19, cylinder 2, and rear plate 20 are fixed by pins 21. Since the inner peripheral surface 2g of the cylinder 2 has a substantially triangular shape, the rotor main body 3a and the cylinder 2 form crescent-shaped spaces lea, 18b, and 18c.

Further, a housing 1 is provided so as to surround the rotor main body 3a, the cylinder 2, and the front plate 19.

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 rotatably supported by the boss portion la of the housing 1 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 is 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 periphery 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 tea, and a discharge port 2b for discharging hydraulic oil from the space tea. Similarly, a suction port 2C for sucking hydraulic oil into the crescent-shaped space 18b and a discharge bow 2d for discharging hydraulic oil from this section 18b are formed in the cam ring 2. A suction port 2e for sucking hydraulic oil into the crescent-shaped space 18e and a discharge boat 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 boat 2a and a discharge passage 6 communicating with the discharge boat 1-2b. 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 boat 2C, a communication hole 8 for communicating the spool hole 12 with the discharge port 2d, and a communication hole 8 for communicating the spool hole 12 with the outside of the housing. Three communicating holes 24, 25 and 26 are provided in the housing l, respectively.

The other housing 1, that is, the housing 1 on the side where the spool hole 13 is formed, has the suction bow 2e.
A communication hole 9 for communication with the discharge boat 2f, a communication article 10 for communication with the discharge boat 2f, and three communication holes 27, 28 and 29 with the outside of the housing are provided. A spool 30 and a spring 31 that biases the spool 30 are inserted into the spool hole 12, 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. Also, grooves 30b are formed on the circumference of the spool 30 at two places.
30C is formed. 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 also has a communication hole 32a1 and a groove 32.
b, 32c are formed.

A suction pipe 34 is connected to the suction passage 5 of the housing l, and the suction pipe 34 and the communication holes 24 and 2 are connected to each other.
6 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. Restriction 15 of this discharge pipe 35
Pipes 38 and 41 connecting the communication holes 26 and 29 are connected to the upstream side, that is, the side closer to the pump. Further, the downstream side of the throttle 15 of the discharge pipe 35, that is, the throttle 1
5, the communication holes 25 and 2 are located on the opposite side of the pump.
8 and this discharge pipe 35 are connected to each other.

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 body 3a to move inside the cylinder 2 clockwise (in the direction of the arrow) in FIG.
Rotate to . Then, the vane 4 inserted into the vane i3d of the rotor main body 3a protrudes in the centrifugal direction due to the 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, the volume of the pump working chamber P formed by the vane 4a and the next vane 4b gradually increases, and hydraulic oil is sucked from each suction port 2a and 2C12e provided on 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 of the discharge boats 2b, 2d, and 2f provided on the cam ring 2. These suction and discharge strokes 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. This flow generates a pressure difference between both ends of the throttle 15 provided in the discharge pipe 35, that is, on the upstream and downstream sides. This differential pressure is applied to the spool hole 1 through the piping 37, 38 and the communication hole 30a provided in the spool 30.
2 to pressure chambers 16 and 17 at both ends of spool 30. Similarly, this differential pressure is transferred to the pressure chambers 40 and 42 at both ends of the spool 32 in the spool hole 13 through the piping 40, 41 and the communication hole 32a provided in the spool 32.
and 43 as well.

First, the case where the pump rotation speed is less than A in FIG. 3 will be explained.

When the pump rotation speed is less than A, the force in the upper part of FIG. 1 that acts on the spool 30 due to the pressure transmitted to the pressure chamber 1 (5) is
1 and the set load of the spring 31. and pressure chamber 42
The force acting on the spool 32 downward in FIG. 1 due to the pressure transmitted to the pressure chamber 43 is added to the force acting on the spool 32 upward in FIG. 1 due to the pressure transmitted to the pressure chamber 43. When it is smaller than the force. 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 hole 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, via the suction passage 5, and from the suction port 2a. Then, it is discharged from the discharge boat 2b through the discharge passage 6 to the discharge pipe 35. Next, this suction pipe 3 is connected to the pump working chamber 18b from the suction pipe 34.
Hydraulic oil is supplied from the communication hole 24, the communication hole 7, and the suction port 2C via the pipe 36 connected to the pipe 4.

The hydraulic oil is then discharged from the discharge bow 1-2d through the communication hole 8 and the communication hole 25 to the pipe 37 and the discharge pipe 35. In addition, the pump working chamber 18C is connected to the suction pipe 34 through a pipe 39 connected to the suction pipe 34, and the communication hole 2 is connected to the pump working chamber 18C.
7. Hydraulic oil is supplied from the communication hole 9 and the suction port 2e. The hydraulic oil is then discharged from the discharge boat 1 through the communication hole 10 and the communication hole 28 to the pipe 40 and the discharge pipe 35.

In other words, the pump work as a whole is performed in three chambers, pump working chambers 18a, 18b, and l8c, and the pump discharge flow rate is the solid line portion of the straight line represented by α in Fig. 3. It becomes.

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, a force acting upwardly on the spool 30 in FIG. 1 due to the pressure transmitted to the pressure chamber 16 is applied to the spool 30 in FIG. It is greater than the force acting downward. Then, the force acting downward in FIG. 1 on the spool 32 due to the pressure transmitted to the pressure chamber 42 is
1 is smaller than the force acting upwardly in FIG. 1 on the spool 32 due to the pressure transmitted to the spring 33 and 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. In other words, the communication holes 25.7.8 are in communication, and the communication hole 24 is not in communication with any other communication holes. 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, via the suction passage 5, and from the suction port 2a. The hydraulic oil is then discharged from the discharge boat 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 the hydraulic oil supplied from the communication hole 7 via the suction bow 2C is equal to the flow rate of the hydraulic oil discharged from the discharge bow 2d via the communication hole 8. In other words, the hydraulic oil discharged from the communication hole 8 is supplied to the pump working chamber 111b again through the communication hole 7 and the suction port 2C. That is,
The flow rate of the hydraulic oil flowing through the communication hole 25 is zero, and since the communication holes 2 and 1 are in a closed state, the flow rate of the hydraulic oil flowing through the pipes 36 and 37 is 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 work as a pump, that is, does not operate.

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

In other words, the pumping work of the pump as a whole is performed in two chambers, the pump working chambers 18a and 18C, and the pump working chamber IJ3b 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 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 the suction port 2C of the working chamber 18b communicate through the communication hole 7.8. At this time, it is possible to make the pressure in the working chamber 18b the suction pressure, but according to the research of the present inventors, when the pressure is made to reach the suction pressure, the pressure in the suction port 2C is
There was a problem that cavitation occurred. 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 this 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. In general, cavitation is 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 sucked oil is sucked in again from the discharge boat through the communication hole 7.8, 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, it is inevitable that there will be edges or sharp bends, especially near the suction port 7, and it has been impossible to eliminate cavitation by changing the shape alone. Therefore, it has been found that it is extremely effective to crush air bubbles in the oil in the working chamber and prevent cavitation by guiding the pressure on the high-pressure discharge side through the pipe 37 as shown in the present invention.

Next, in FIG. 3, the case where the pump rotation speed is 8 or more will be explained.

When the pump rotation speed is 8 or more, the differential pressure generated before and after the throttle 15 becomes even larger than when the pump rotation speed is A or more and less than B, as described above, so the spool 30 in the spool hole 12 is It is located in the same position as in Figure 4).

Also, the pressure transmitted to the pressure chamber 42 causes the spool 3 to
The force acting on the spool 32 downward in FIG. 1 becomes larger than the force acting on the spool 32 upward in FIG. 1 due to the pressure transmitted to the pressure chamber 43 and 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. 24 is in a state where it does not communicate with any other communication hole. Also, the communication holes 9, 10, and 40 are in communication, and the communication hole 27 is not in communication 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 port 2a via the suction pipe 34 and the suction passage 5. The hydraulic oil is then discharged from the discharge port 2b to the discharge pipe 35 via the discharge passage 6. Next, when looking at the pump working chamber 18b, the spool 1
The position of the spool 30 in 2 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, and the pump working chamber 18b does not perform any work as a pump. be.

Also, the pump working chamber 18c will be explained.

As mentioned above, the communication holes 9, 19, and 40 are in communication, and the flow rate of the hydraulic oil supplied from the communication hole 9 through the suction port 2e is from the discharge boat 2f to the communication hole lO.
Since the flow rate of the hydraulic oil discharged through the communication hole 1 is equal to the flow rate of the hydraulic oil discharged through the
The hydraulic oil discharged from 0 is passed through the communication hole 9 to the suction port 2e.
After that, it is again supplied to the pump working chamber 18C.

That is, the flow rate of the hydraulic oil flowing through the communication hole 25 is zero,
Furthermore, since the communication hole 24 is in a closed state, the piping 39
The flow rate of hydraulic oil flowing through and 40 becomes zero.

Therefore, the pump working chamber 18c is in an operating state in which 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, pumping work for the pump as a whole is performed only in the pump working chamber 18a, and the pump working chambers 18b and 18c do not perform any work as a pump. Therefore, the pump discharge flow rate is the solid line portion of the straight line represented by T in FIG. In this case, the pump working chambers 18b, 18
The high-pressure discharge side hydraulic oil is guided into c, as described above.

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

Note that the points where the pump working chamber changes from 3 to 2 and from 2 to 1, that is, points A and B in FIG. 3, are determined by the shape of the throttle 15, the spring 31, and It goes without saying that the optimum value can be changed by changing the set load of 33.

Furthermore, in this embodiment, the hydraulic oil on the high-pressure discharge side is guided to the pump working chamber that is not operating, that is, doing no work, but this is to prevent cavitation that occurs during high-speed operation as described above. Figure 6 shows the effect.

In FIG. 6, σ is the configuration of this embodiment, and ε is a configuration in which hydraulic oil on the suction side is guided into the pump working chamber which is not in operation, without guiding hydraulic oil on the high-speed discharge side. FIG. 6 shows the pumps in the two configurations described above.
This shows the relationship between rotation speed and noise level.

FIG. 6 shows measurements taken at a position 25 cm behind the pump under test conditions of a discharge pressure of 50 kg/c4 and an oil temperature of 80°C. As can be seen from the figure, the pump according to this embodiment (
σ) has a lower noise level, especially during high-speed operation, and is highly effective compared to a pump (ε) that 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. Recognize.

Next, a second embodiment will be described.

In the first embodiment, as the rotation speed of the pump increases,
The structure is such that the number of pump working chambers changes from 3-2-1, but if the number of pump working chambers does not need to be 2, a structure where the number of pump working chambers changes from 3 to 1 is possible. By doing so, the number of parts can be reduced, making it possible to reduce the size and weight.

Here, the configuration of this embodiment will be explained. In FIG. 7, the housing 100 is provided with one spool hole 12, and the spool hole 12 has a communication hole 102 that communicates with the suction port 2C and a communication hole 1 that communicates with the discharge port 2d.
04, communication holes 24 and 25 communicating with the outside of the housing 100 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 105 that communicates with the outside of the housing 100.

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 107 that communicates between the discharge port 2f and the outside of the housing 100. Here, the communication hole 1
03 and 106 are connected by piping 108, and communication hole 1
05 and 107 are connected by a pipe 109.

The operation of the second embodiment with the above configuration will be explained.

In FIG. 8, when the pump rotational speed is less than C, 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 that acts on the spool 30 upward in FIG. 7 due to the pressure transmitted to the pressure chamber 16 acts on the spool 30 downward in FIG. 7 due to the pressure transmitted to the pressure chamber 17 and the set load of the spring 110. smaller than the power to That is, the spool 30 in the spool hole 12 is in the position shown in FIG.

When this pump is operated in the above-mentioned R mode, as in the case where the pump rotation speed is less than A as described in the first embodiment of the present invention, the three chambers 18a, 18b, and 18c are operated. This is where pumping work is done. At this time, the discharge flow rate of the pump becomes the solid line portion of the straight line represented by α' in FIG.

Next, in FIG. 8, consider the case where the pump rotation speed is C or higher. The force acting on the spool 30 upward in FIG. 7 due to the pressure transmitted to the pressure chamber 16 is equal to the force acting on the spool 30 downward in FIG. 7 due to the pressure transmitted to the pressure chamber 17 and the set load of the spring 110. , and the spool 30 within the spool hole 12 moves to the position shown in FIG.

When this pump is operated in the above state, the pump work is performed only in the pump working chamber 18a, as in the case where the pump rotation speed is 8 or more in the first embodiment of the present invention, and the pump working chamber 18a is operated. 18b and tSC are in an operating state where there is no pressure difference between suction pressure and discharge pressure. 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 to 3-1 as the rotation speed increases, and the driving horsepower at high rotation speeds can be reduced. It has a technical effect. 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, the configuration of the second embodiment can be changed so that the number of pump working chambers changes 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. In this embodiment, a cylinder 200 having an inner peripheral surface 200a that forms two pump chambers on the circumference is fitted into a housing 201, and the cylinder 200, the rotor 3, and the vane 4 form two pump operating chambers 202a and 202b. It forms a partition. These two pump working chambers 202
Of the pump working chambers 202a and 202b, the pump working chamber 202a always performs a pumping action, and by switching the oil passage of the hydraulic oil introduced into the pump working chamber 202b by the spool 203, the working chamber that performs the pumping action is changed to 2-1. The configuration is such that Here, a pressure chamber 204 formed at one end of the spool 203 is provided with a communication hole 205 so as to guide the pressure of the hydraulic fluid discharged from the pump working chamber 202b, and a pressure chamber 207 at the other end is provided. There is a discharge pipe 20
The pressure of the hydraulic oil after passing through the restrictor 206 provided at 8 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 rotational 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. Due to the balance between this load and the set load of the spring 209, the spool 203 moves,
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. The first invention described above
In the second and third embodiments, each pump working chamber had the same volume, but the number of pump working chambers that performed the pumping action was
If the discharge flow rate required in the minimum case is smaller, the volume of the pump working chamber 300a that constantly performs pumping action is made smaller than the other pump working chambers 300b and 300C, as shown in FIG. . This has the effect of 9) J 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>300
It is obvious that a or 300b=300c>300a may also be satisfied.

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. It goes without saying that it is possible to control the number of pump operating chambers.

〔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. It operates by controlling the In other words, by changing the number of pump working chambers, the discharge amount from the pump as a whole is changed, which has the effect of reducing the power consumption of the pump according to 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 cavity generated therein is guided. Another advantageous effect is that silane 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 the drawing]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a sectional view taken along line nn in FIG. 1, FIG. 3 is a diagram for explaining the first embodiment, and FIG. 4 , FIG. 5 is a cross-sectional view for explaining the operation of the first embodiment, FIG. 6 is a cross-sectional view for explaining the first embodiment, and FIG. 7 is a cross-sectional view for explaining the second embodiment of the present invention. 8 and 9 are diagrams for explaining the second embodiment, FIG. 1O is a sectional view showing the third embodiment, and 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, 2C9
7, 24...Suction port and communication hole forming a suction flow path. 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, 2d, 8.25... Discharge flow path Eggplant discharge port, communication hole, discharge passage, 2f, 10.28・
...Discharge ports and communication holes that form the discharge flow path. Discharge passages, 18a, 18b, 18c... Spaces that are a plurality of pump operating chambers, 30.32... Spools that are switching means, 37.40... Piping that forms flow paths. Representative Patent Attorney Takashi Okabe Fig. 1 Fig. 6 O,'n-ym times f-public software (rl) m) Fig. 7 Fig. 8 °n 7/Rotation speed Fig. 9

Claims (1)

[Scope of Claims] (1) A rotor that rotates in response to a driving force, a vane groove provided with a closed opening on the rotor, a vane slidably inserted into the vane groove, and a vane provided on the outer periphery of the rotor. a cylinder having a non-circular inner circumferential surface that is arranged and forms a plurality of pump working chambers with the rotor and the vane;
a plurality of suction passages for sucking 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 at least one of the suction passage and the discharge passage. A vane type variable displacement pump characterized by comprising a switching means for communicating with the. 12) At least one of the pump working chambers in which the suction passage and the discharge passage are in communication with each other by the switching means is provided with a chamber in which the suction passage and the discharge passage are not in communication with each other. The vane type variable displacement pump according to claim 1, wherein the flow paths through which the pressure on the discharge side of the chambers is guided are in communication. (3) At least one of the pump working chambers is connected to the other (4)
) The pump working chamber having the smallest volume among the pump working chambers is not provided with the switching means for communicating the suction passage and the discharge passage of the pump working chamber. Vane type variable displacement pump.