JP2003176791A - Variable displacement vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement vane pump with small energy loss. <P>SOLUTION: The upstream side and the downstream side of an variable throttle 25b of a delivery passage 33 are connected to each other via bypass passages 75 and 76 provided with a load pressure sensitive valve F. The valve F closes the bypass passages 75 and 76 when the load pressure is equal to or below the predetermined pressure, and opens the bypass passages 75 and 76 when the load pressure exceeds the predetermined pressure, to make pressure oil at the upstream of the variable throttle confluent with the delivery passage 33 at the downstream of the variable throttle 25b via bypass passages 75 and 76. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention
Variable displacement vane pump for water steering system
About. 2. Description of the Related Art Used for a vehicle power steering device.
FIGS. 5 to 10 show a variable displacement vane pump.
Is conventionally known. This conventional variable capacity base
The pump is formed on the body 1 as shown in FIG.
A Side plate 3 and adapter ring 4
Assembled in layers. In addition, the line VI-VI in FIG.
As shown in FIG.
On the inside, a cam ring 5 is installed and this cam
Rotate the ring 5 around the pin 6 in the adapter ring 4
Making it possible. For example, a phase of 180 degrees is
A seal member 7 is provided at the shifted position. Soshi
The cam member is formed by the seal member 7 and the pin 6.
Between the first pressure chamber 8 and the second
Two pressure chambers 9 are defined. The first pressure
The capacity of the force chamber 8 and the second pressure chamber 9 is
It changes in accordance with the turning position of. A rotor 10 is provided inside the cam ring 5.
Is provided. The rotor 10 has an engine (not shown).
It is fixed to a drive shaft 11 linked to the gin. Accordingly
To operate the engine to rotate the drive shaft 11
And the rotor 10 rotates integrally with the drive shaft 11.
You. The rotor 10 has a plurality of slits 12.
And slits 12 with vanes 13
It is crowded. These vanes 13 can move in and out in the radial direction
And the centrifugal force generated by the rotation of the rotor 10.
When they act, they protrude from the slit 12. And
The tip of the shaft 13 against the inner periphery of the cam ring 5
As a result, a plurality of pump chambers 14 are formed between the vanes 13.
I am trying to be. [0005] The cam ring 5 has a drive shaft 1 on its inner periphery.
1 with the drive shaft 11
When the rotor 10 rotates, each pump chamber
The volume of 14 also changes. And according to this rotation the volume
The pump chamber 14, which is enlarged, is set as the suction side, and this enlarged
The working oil is sucked into the pump chamber 14. Also, with rotation
The pump chamber 14, whose volume is reduced, is used as the discharge side,
Hydraulic oil is discharged from the contracting pump chamber 14. In addition,
In FIG. 6, when the rotor 10 rotates counterclockwise,
Pump chamber 14 located in the upper left area from the suction side
And the pump chamber 1 located in the range from the lower left side to the lower right side.
4 is the ejection side. [0006] As shown in FIG.
A cover 20 is fixed to the surface, and the cover 20
It is blocking A2. Also, the support formed on the cover 20 is
While inserting the tip of the drive shaft 11 into the holding hole 65,
Bearing 1 in which the drive shaft 11 of FIG.
5 support it rotatably. Of the cover 20
A high-pressure recess 16a and a low-pressure recess 17a are formed on the mating surface.
Has formed. The high-pressure recess 16a and the low-pressure recess 1
7a on the mating surface of the side plate 3 facing
Also has a high-pressure recess 16b and a low-pressure recess 17b.
You. Then, the high-pressure recess 16a and the high-pressure recess 16b are
The low-pressure recess 17a is opposed to each other,
Are opposed to each other. [0007] As shown in FIG.
At the lower side of the drawing where the pump chamber 14 on the discharge side is located.
I have. Therefore, the water discharged from the discharge side pump chamber 14
The pressure oil is guided to the high-pressure recess 16b, and
As shown in FIG. 5, the pressure oil guided to the high pressure recess 16b is
High-pressure chamber through a high-pressure passage 18 formed in the id plate 3
28. On the other hand, the low pressure recess 1
7b is the upper side of the drawing where the suction side pump chamber 14 is located.
Is provided. Therefore, the pump chamber 14 on the suction side
, A low pressure passage through a suction port 21 formed in the cover 20.
Hydraulic oil guided to the low-pressure recess 17a through the passage 19 is sucked.
You will be rare. The body 1 is provided with an opening adjustment mechanism A.
It is crowded. This opening adjustment mechanism A is, as shown in FIG.
Then, one of the mounting holes 22 formed in the body 1 is
Third fluid chamber defined by the stopper ring 4 and the bore 2
31. In addition, other than this assembling hole 22
Side to the outside, and this opening
Is closed by the cap 25. The cap 25
An annular recess 25a is formed on the outer periphery of the annular recess 2a.
A first fluid chamber 29 is formed between 5a and the mounting hole 22.
ing. The first fluid chamber 29 has a line VII-VII in FIG.
As shown in the plan view of FIG.
The pressure chamber 28 communicates. The first fluid chamber 29
Is formed through a throttle hole 25b formed in the cap 25.
The second fluid chamber 30 in the cap 25 communicates with the second fluid chamber 30. Further, a control plug is provided in the cap 25.
The lancer 23 is slidably incorporated. This control
A flow hole 32 is formed at the tip end of the
The second fluid chamber 30 and the third fluid chamber 31 are
Is communicated. Therefore, the pressure introduced from the high pressure chamber 28
The oil is supplied from the first fluid chamber 29 → the throttle hole 25b → the second fluid chamber 30
→ Flow hole 32 → Guided to third fluid chamber 31. And this
The pressure oil led to the third fluid chamber 31 is formed in the body 1
It is guided to the discharge port 34 via the discharge passage 33. What
FIG. 10 is a schematic view of this conventional vane pump.
The same reference numerals are given to the same components. This
As shown in the figure, the discharge oil from the high-pressure chamber 28
Throttle hole 25b → discharge passage 33 → through discharge port 34
The power is supplied to the power steering device PS. [0010] Further, at the tip side of the control plunger 23,
Has a feedback pin 26. And this
Feedback pin 26 is formed on the adapter ring 4
Through the hole 27. On the other hand, the second fluid chamber 3
0, a spring 35 is incorporated and
Applying the elastic force of the ring 35 to the control plunger 23
I have. Then, at the tip of the control plunger 23,
By pressing the feedback pin 26,
The elastic force of the spring 35 through the feedback pin 26
It acts on the cam ring 5. Note that the feedback
To reduce the clearance between the pin 26 and the hole 27.
As a result, the feedback pin 26 and the hole 27
The third fluid chamber 31 communicates with the second pressure chamber 9 via a gap
I try not to. The feedback pin 26 is pressed.
The cam ring 5 rotates leftward in the drawing with the pin 6 as a fulcrum,
The left outer peripheral surface is pressed against the inner periphery of the adapter ring 4.
Have been. Thus, the cam ring 5 is connected to the adapter ring 4
, The amount of change in volume of the pump chamber 14 is maximized.
As a result, the flow rate discharged from the discharge side pump chamber 14 becomes maximum.
You. Also, if the cam ring 5 is at the leftmost position,
For example, the control plunger 23 also moves to the leftmost position.
The opening degree of the throttle hole 25b is maximized. That is, the cam
When the ring 5 is at the leftmost position, as shown in FIG.
High pressure chamber 28 and power steering device PS
The opening degree of the throttle in the flow path process becomes maximum. In the above state, the cam ring 5 supports the pin 6.
When turning to the right to the point, the feedback pin 26
Control plunger 23 also moves to the right.
Move. When the control plunger 23 moves rightward,
Aperture 25b is formed by the right end of the control plunger 23 of FIG.
It will be closed. That is, the opening adjustment mechanism A
Thus, the movement of the cam ring 5,
Depending on the amount of eccentricity of the cam ring 5, the opening of the throttle hole 25b is
I control it. Also, the opening adjustment mechanism A
Holds the initial position of the cam ring 5 as described above.
It also has the function of On the other hand, as shown in FIG.
Is a control valve B for controlling the rotational position of the cam ring 5.
Incorporated. This control valve B is, as shown in FIG.
In the mounting hole 40 formed in the body 1, the spool 4
1 and a spring 42 are incorporated. Also, this group
When the opening of the mounting hole 40 is closed by the cap 43
Also, the rod of the spool 41 is
Press the part 41a to set the initial
The force is applied to the spool 41. The spool 41 has a first land 38
And a second land portion 39.
A first pilot chamber 49 is formed between the
The second pyro between the land portion 39 and the bottom of the mounting hole 40
A cut chamber 50 is formed. Also, the first land portion 38
A drain chamber 37 is formed between the second land portion 39 and the second land portion 39.
I have. The first pilot chamber 49 is, as shown in FIG.
Communicates with the high-pressure chamber 28 through a passage 61,
28 to the first pilot chamber 49
I have. The second pilot chamber 50 has a
The discharge port 34 is communicated through the pilot passage 47
I have. The power steering connected to the discharge port 34
The load pressure of the ring device PS is controlled via the pilot passage 47.
To the second pilot room 50. Further
The drain chamber 37 shown in FIG.
48, and the drain port 48
The chamber 37 communicates with the tank. Furthermore, the above
An annular groove 44 for drain and a throttle groove 46 are formed in one land 38.
Is formed, and is connected to the drain annular groove 44 through the throttle groove 46.
And the communication chamber 37. A first passage 51 is formed in the mounting hole 40.
We are communicating. This first passage 51 is, as shown in FIG.
Through a first through hole 63 formed in the adapter ring 4.
And communicates with the first pressure chamber 8. And the state shown
Then, the first pressure chamber 8 is connected to the first through hole 63 → the first passage 51 →
Drain annular groove 44 → throttle groove 46 → drain chamber 37 → drain
It communicates with the tank through the port 48. Further, a hole is formed on the inner periphery of the assembling hole 40.
The second passage 52 communicates with the annular groove 53. this
As shown in FIG. 6, the second passage 52 is
Communicates with the second pressure chamber 9 via the second through hole 64 formed in
are doing. The second pressure chamber 9 has a small hole shown in FIG.
The second pressure chamber communicates with the high pressure chamber 28 via
The pressure from the high-pressure chamber 28 is led to 9. So
Then, as shown, the annular groove 53 is
When the pressure in the second pressure chamber 9 is high
It is kept at the same pressure as the chamber 28. As described above, the second pressure chamber 9 is the same as the high pressure chamber 28.
The first pressure chamber 8 is maintained at the tank pressure.
The cam ring 5 has its left side
The state of being pressed against the inner periphery of the taring 4 is maintained. in this way
When the cam ring 5 is at the most left-turned position,
The volume change amount of the pump chamber 14 becomes maximum, and the discharge amount also becomes maximum.
You. The control valve B and the first and second pressure chambers
8, 9, etc., the position of the cam ring 5 is adjusted according to the discharge amount.
The operation will be described later. In the spool 41 of the control valve B,
Incorporates a relief valve R as shown in FIG.
You. This relief valve R is connected to a discharge port 34
It regulates the maximum pressure of the water steering device PS.
You. That is, the control valve B is
The sheet member 55 incorporated and the sheet member 55
A ball 57 for blocking the formed passage 56 and the ball 5
7 and a ball 57 for seating
And a spring 59 for pressing against the member 55
I have. Usually, the spool 41 is moved by the ball 57.
Although the communication between the inside and the passage 56 is blocked,
The load pressure of the ring device PS is set by a spring 59.
When the pressure exceeds the set pressure, the ball 57 is moved to the seat member 55.
Away from the second pilot chamber 50 and the inside of the spool 41
Communicate. Thus, the second pilot chamber 50 and the spoo
When the inside of the vehicle 41 communicates, the power steering device PS
The load pressure of the discharge port 34 → the pilot passage 47 → the
2 Pilot chamber 50 → passage 56 → inside spool 41 → sp
Discharge hole 60 formed in the hole 41 → drain chamber 37 → drain
It is discharged to the tank via port 48. Also, with this
When the spool 41 moves to the right in the drawing,
Pressure oil supply to the first pressure chamber 8 and pressure oil discharge from the second pressure chamber 9
The eccentricity of the cam ring 5 is reduced by the protrusion.
As described above, the highest power steering device PS
The pressure is controlled. Next, the operation of the conventional vane pump will be described.
I will tell. First, the rotor 10 is driven by driving the engine.
When rotated, the vanes 13 protrude due to centrifugal force,
A number of pump chambers 14 are formed. And the upper part in FIG.
In this position, hydraulic oil is sucked into the suction side pump chamber 14.
The operating oil sucked into the pump chamber 14
Compressed with 10 rotations. And this compressed
When the pressure oil reaches the lower position from the pump chamber 14,
It is discharged to the pressure chamber 28 (see FIG. 5). The discharged oil discharged into the high-pressure chamber 28
6 (see FIG. 7) to the first fluid chamber 29. So
Then, as shown in FIG.
25b → second fluid chamber 30 → flow hole 32 → third fluid chamber 31
→ Discharge passage 33 → Power steering via discharge port 34
It is supplied to the ring device PS. Thus, the high pressure chamber 2
8 is discharged to the power steering device PS
When supplied, a pressure difference occurs before and after the throttle hole 25b.
The pressure on the upstream side of the throttle hole 25b is as shown in FIG.
As shown, the first pipe of the control valve B is
Guided to the lot chamber 49, the pressure downstream of the throttle hole 25b
Is connected to the second valve of the control valve B through the pilot passage 47.
It is led to the Ilot room 50. Therefore, the spool of the control valve B
41 is based on the pilot pressure of the first pilot chamber 49.
The thrust in the right direction in the drawing and the pilot
G and the elastic force of the spring 42
Thrust works. And balance these thrusts
The spool 41 moves to the position. The pressure difference before and after the throttle hole 25b is
At low rotations with a small discharge rate because it is proportional to the flow rate
Has a small differential pressure generated around the throttle hole 25b. That
The control valve B is moved by the spring 42 in FIG.
The first pressure chamber 8 is connected to the tank at this time.
The high pressure of the high pressure chamber 28 is supplied to the second pressure chamber 9 through the small holes 54.
Guided through. In other words, while the pump is running
Keeps the cam ring 5 at the maximum eccentric position shown in the figure.
You. Therefore, the flow rate discharged from the discharge port 34
Increases with the rotation speed of the pump. From the above state, the pump rotation speed rises,
As the pump discharge amount increases, the differential pressure across the throttle hole 25b also increases.
It will be good. The differential pressure causes the spool 41 to work.
The right thrust to be used is the initial bullet of the spring 42
When the force exceeds the force, this spool 41 moves to the right.
Moving. As a result, the first pilot chamber 49 and the first passage
51, and through the first passage 51 → the first through hole 63.
The pressure is introduced into the first pressure chamber 8 at the same pressure as the high pressure chamber 28.
At this time, the second pressure chamber 9 is moved from the second through hole 64 to the second
Passage 52 → annular groove 53 → notch 62 → via drain chamber 37
To communicate with the drain port 48. Therefore, Camry
Ring 5 is formed by a pressure difference between the first pressure chamber 8 and the second pressure chamber 9.
The spring 35 of the opening adjustment mechanism A is generated by the generated force.
Rotates to a position that balances with the spring force of. As described above, the cam ring 5 is moved rightward.
, The rate of change in volume of the pump chamber 14 decreases.
As a result, the displacement volume per rotation of the rotor 10 is also reduced.
Here, the discharge amount of the pump means one time of the rotor 10.
Multiply the displacement by the number of rotations
Things. Therefore, as the rotational speed of the rotor 10 increases,
At the time when it rises, the displacement per rotation
When the product starts to be reduced, the discharge amount is kept constant.
That is, when the predetermined discharge amount is reached, the eccentricity of the cam ring 5
Adjust the volume to keep the discharge rate constant
You. And the eccentric amount of the cam ring 5 with respect to this discharge amount
Control of the control valve B, the first and second pressure chambers 8, 9 and
And the aperture 25b. As described above, the discharge amount of the pump is stable.
Then, if the rotation speed of the rotor 10 is further increased,
The mulling 5 further rotates rightward. And this mosquito
The control plug of the position detecting mechanism A is
The jar closes the throttle hole 25b. Therefore,
Hydraulic oil supplied to the discharge port 34 through the through hole 25b
Is limited. Further, the opening degree of the throttle hole 25b is reduced.
And the pressure difference before and after that also increases,
The spool 41 of the control valve B moves further rightward.
You. Therefore, the cam ring 5 further rotates rightward,
Thereby, the discharge amount is further reduced. Toes
In the above conventional example, if the engine speed is in the low rotation range,
Flow increases, but from the time when the
During the separation, keep the flow constant and increase the rotation speed
This time, the flow control characteristics are set to reduce the flow.
I have decided. The above-mentioned conventional variable capacitance type
In the vane pump, the power steering device PS side negative
Since the discharge rate is controlled without considering the load,
There was a problem that gyros occurred. For example, go straight
If the steering is not operated during
The flow rate supplied to the tearing device PS is small.
However, in the above conventional example, a predetermined flow rate control is performed according to the number of rotations.
Because the characteristics are always exhibited, even when driving straight,
Supplying more flow than necessary to the steering system PS
Was. In particular, during low / medium speed driving, there is a large amount of discharge.
Energy loss has occurred. The purpose of this invention is to
Provide variable displacement vane pump with low energy loss
Is Rukoto. According to the present invention, a housing is provided.
There is a cam link built so that it can be eccentric to the drive shaft.
And inside the cam ring,
A rotor that rotates integrally with the drive shaft, and
Between the vanes and multiple vanes
Multiple pump chambers formed and the pressure discharged from the pump chambers
A discharge passage that guides oil to the discharge port
Variable throttle provided in the discharge passage of
Cam that controls the amount of eccentricity of the cam ring according to the flow rate
The above is possible according to the ring control mechanism and the eccentric amount of the cam ring.
An opening adjustment mechanism for controlling the opening of the variable throttle;
Depending on the amount of eccentricity of the
Variable displacement vane pump with variable displacement
Between the upstream and downstream sides of the variable throttle of the discharge passage.
Connect via the pass passage and this bypass passage
The load pressure sensitive valve is installed in the
When the load pressure is lower than the set pressure, close the bypass passage and
When the pressure exceeds the set pressure, open the bypass passage and adjust
The pressure oil on the upstream side of the throttle passes through the bypass passage under the variable throttle.
It is designed to join the discharge passage on the upstream side.
You. DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention shown in FIGS.
The embodiment is characterized in that a load pressure sensitive valve F is provided.
Things. Basic as a variable displacement vane pump
The basic structure and its basic operation are the same as in the previous example.
It is like. Therefore, in the following, the load pressure sensitive valve
The configuration and operation of the valve F are mainly described, and the same configuration as the conventional
Elements are given the same reference numerals and detailed descriptions are omitted.
I do. Note that the body 1 and the cover 20 of this embodiment
Thus, the housing of the present invention is configured. As shown in FIG. 1, a load is
The pressure sensitive valve F is incorporated. This load pressure sensitive valve
As shown in FIG.
The spool 71 is slidably incorporated in the attachment hole 70.
You. Also, the opening of the mounting hole 70 is
Therefore, the cap 72 and the spool 71 are closed.
Is defined as a pilot room 73. In addition, sp
A spring 74 is installed at the tip side of the
The initial elastic force of the spring 74 is
To act on. The cover 20 has a first communication passage 75 and a
A two-way passage 76 is formed. The first communication passage 75
Is connected at one end thereof to the third fluid chamber 31 as shown in FIG.
And the other end thereof communicates with the pilot chamber 73.
You. The second communication passage 76 has one end assembled.
It communicates with an annular groove 77 formed on the inner periphery of the hole 70, and the other end is high.
It communicates with the pressure chamber 28 (see FIG. 4). FIG.
Is a schematic diagram of this embodiment, and illustrates the same components.
Are denoted by the same reference numerals. As shown in FIG.
The load pressure sensitive valve F is connected to the high pressure chamber through the second communication passage 76.
Pressure oil of the same pressure as 28 is led. Therefore, load pressure feeling
When the response valve F opens, the load pressure response valve F
Pressure oil is supplied to the power steering device PS. Note that, as shown in FIG.
Is formed on the cover 20 in the spring chamber 78 incorporating
Through the discharge hole 79, which communicates with the low-pressure support hole 65.
I have. The spool 71 has an axial hole 80 formed therein.
One end of the axial hole 80 is opened in the pilot chamber 73.
I'm talking. The bottom of the axial hole 80 is
A radial hole 81 opening on the outer periphery of the
You. This radial hole 81 is in a normal state as shown in FIG.
Although communication with the groove 77 is interrupted, as shown in FIG.
In addition, a large load pressure is introduced to the pilot chamber 73.
Therefore, the spool 71 moves against the spring 74.
Then, it communicates with the annular groove 77. Thus the radial hole
81 and the annular groove 77 communicate with each other,
The pressurized oil flows into the second communication passage 76 → the annular groove 77 → the radial hole 81 →
Axial hole 80 → pilot chamber 73 → second communication passage 75 → second
It is supplied to the three fluid chamber 31. The pressure supplied to the third fluid chamber 31 is
The oil is discharged from the discharge passage 33 to the discharge port 3 as shown in FIG.
4 to the power steering device PS.
And As shown, the load pressure sensitive valve F
Is the upstream side of the variable aperture formed by the aperture 25b.
And a passage connecting the downstream side. And this load pressure
The first communication passage 75 and the second communication passage 7 to which the sensitive valve F is connected
6 corresponds to a bypass passage of the present invention.
You. Next, the operation of this embodiment will be described.
Also in this embodiment, the basic flow control characteristics
Same as the previous case. That is, even in this embodiment,
When the number is low, the flow rate increases
The flow rate remains constant for a while after the rotation speed exceeds
At higher speeds, reduce the flow rate
are doing. However, in this embodiment, the power steering
The flow rate can be further controlled according to the load pressure of the ring device PS.
I am able to do it. For example, when driving straight ahead
Mostly requires the assisting power of the steering system PS
If not, the load pressure on the power steering device PS
Is also low. With such a low load pressure, the load-sensitive valve F
Of the pilot chamber 73 is also low. Because power
The load pressure of the steering device PS changes from the discharge port 34 to the discharge port.
Outgoing passage 33 → third fluid chamber 31 → via first communication passage 75
Because it leads to the pilot chamber 73 of the load sensitive valve F
It is. Therefore, the load pressure sensitive valve F is
The first communication passage 75 and the second communication passage 76
Communication is blocked. As described above, by the load pressure sensitive valve F,
The communication between the first communication passage 75 and the second communication passage 76 is interrupted.
The pressure oil at the same pressure as the high-pressure chamber 28 as shown in FIG.
In addition, passage 36 → throttle hole 25b → discharge passage 33 → discharge port
Supplied to the power steering device PS via the
You. At this time, power stearin is passed through the throttle hole 25b.
The flow rate supplied to the power supply PS
Minimum flow that does not cause response delay in tearing device PS
The amount has been set. That is, the power steering device P
When the assist power of S is not required, the necessary minimum flow
Only the amount is supplied. From the above state, for example, the steering wheel
When the steering wheel is steered, the negative
The load pressure increases. Therefore, the load pressure sensitive valve F
The pressure in the lot chamber 73 rises, thereby causing the spool 7
1 is switched, and the first communication passage 75 and the second communication passage 76
Communicate. Thus, the upstream side and the downstream side of the throttle hole 25b
Side communicates via the load pressure sensitive valve F,
The pressure oil discharged from the chamber 28 passes through the load pressure sensitive valve F.
Converges downstream of the throttle hole 25b. That is, the aperture
Flow rate passed through hole 25b and passed through load pressure sensitive valve F
The total flow rate with the set flow rate is the power steering device PS
Supplied to This total flow is the power steering
It is necessary for the device PS to exhibit the predetermined assist force.
The flow rate is set to Therefore, power stearin
Device PS exerts a predetermined assisting force.
You. As described above, according to this embodiment, the
Required only when using the water steering device PS
Is discharged, so wasteful flow
Supply to the power steering device PS can be prevented
You. Also, make the displacement of the pump chamber 14 small.
This prevents the useless flow rate from being discharged.
Therefore, the driving torque is also reduced. Thus the driving torque
, The fuel efficiency of the car is also improved. further,
Since the discharge rate is reduced, the power steering device
The pipe resistance generated on the PS side also decreases. In this way,
If the drag decreases, the circuit pressure of the entire system can be reduced.
As a result, driving torque can be reduced
Wear. Further, a power steering device PS
This power by reducing the flow supplied to the
The oil temperature reduction effect of the steering device PS can also be expected. You
That is, pressure oil is supplied to the power steering device PS.
The temperature of the device itself rises due to pipe resistance.
A special cooling device such as an oil cooler
Some vehicles have a device. But as mentioned above, the oil
By the temperature reduction effect, the temperature of the power steering device PS
Temperature rise, a special cooling device such as an oil cooler
Installation is not required. In other words, the oil temperature reduction effect
Reduce the cost of the entire system, not just the cost.
Can also be. In the above embodiment, the vehicle powers
The example used for the tearing device has been described.
The light vane pump can be used in other devices.
In particular, when supplying pressurized oil to equipment with variable loads,
The above energy saving effect can be expected. Only when the load pressure exceeds the set pressure, the load becomes negative.
Open the load pressure-sensitive valve, join the discharge oil, and
The load pressure is below the set pressure.
If so, the supply flow rate can be reduced during that time. This
The supply amount can be reduced as in
Energy loss can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an embodiment. FIG. 2 is a partially enlarged sectional view of a load pressure sensitive valve. FIG. 3 is a partially enlarged sectional view of a load pressure sensitive valve. FIG. 4 is a schematic diagram of the embodiment. FIG. 5 is a sectional view of a conventional example. FIG. 6 is a sectional view taken along line VI-VI of FIG. 5; FIG. 7 is a sectional view taken along line VII-VII of FIG. 6; FIG. 8 is a partially enlarged view of an opening adjustment mechanism A; FIG. 9 is a partially enlarged view of a control valve B. FIG. 10 is a schematic view of a conventional example. DESCRIPTION OF SYMBOLS A Opening adjustment mechanism B Control valve F constituting cam ring control mechanism of this invention Load pressure sensitive valve 1 Body 5 constituting housing of this invention Cam ring 8 First constituting cam ring control mechanism of this invention Pressure chamber 9 Second pressure chamber 10 that constitutes the cam ring control mechanism of the present invention Rotor 11 Drive shaft 13 Vane 14 Pump chamber 25b Throttle hole 33 that constitutes the variable throttle of the present invention Discharge passage 34 Discharge port 75 The bypass passage of the present invention Constituting first communication passage 76 Second communication passage constituting the bypass passage of the present invention

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Claims (1)

Claims 1. In a housing, a cam ring incorporated eccentrically with respect to a drive shaft, a rotor incorporated inside the cam ring and rotated integrally with the drive shaft, and a rotor A plurality of vanes incorporated so as to be able to protrude and retract in the radial direction, a plurality of pump chambers formed between the vanes, a discharge passage for guiding pressure oil discharged from the pump chamber to a discharge port for connecting a load, and a discharge passage. A variable throttle provided in the passage, a cam ring control mechanism for controlling the amount of eccentricity of the cam ring according to the flow rate discharged from the pump chamber, and an opening adjustment for controlling the opening of the variable throttle according to the amount of eccentricity of the cam ring A variable displacement vane pump in which a displacement per rotation of the rotor is varied by an eccentric amount of the cam ring. The upstream side and the downstream side are connected via a bypass passage, and a load pressure sensitive valve is provided in the bypass passage. The load pressure sensitive valve closes the bypass passage when the load pressure is equal to or less than a set pressure, and A variable displacement vane pump characterized in that the bypass passage is opened when the pressure exceeds a set pressure, and the hydraulic oil upstream of the variable throttle is joined to the discharge passage downstream of the variable throttle via the bypass passage. .