JP2004293414A - Variable capacity vane-pump and pressure supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable capacity vane-pump in which energy loss is small. <P>SOLUTION: The variable capacity vane-pump is provided with a branch path 68 branched from the upstream of a throttle 67 in a delivery path 66, and a pressure-sensitive valve F provided in the branch path 68. The pressure-sensitive valve F allows the branch path 68 to communicate with the suction side when a load pressure is at most a set pressure, while the valve F allows the branch path 68 to communicate with a delivery path 66 downstream of the throttle 67, when the load pressure is higher than the set pressure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable displacement vane pump and a pressure supply device that are optimal for a power steering device of a vehicle.
[0002]
[Prior art]
The prior art shown in FIGS. 5 to 10 has already been filed by the present applicant as Japanese Patent Application No. 2001-377008.
As shown in FIG. 5, a side plate 3 and an adapter ring 4 are assembled in a bore 2 formed in a body 1 in a stacked state.
As shown in FIG. 6 which is a cross-sectional view taken along the line VI-VI in FIG. 5, a cam ring 5 is incorporated inside the adapter ring 4 and the cam ring 5 is mounted inside the adapter ring 4 with a pin 6 as a fulcrum. It is rotatable.
[0003]
A seal member 7 is provided at a position shifted by, for example, 180 degrees from the pin 6. The first pressure chamber 8 and the second pressure chamber 9 are defined between the cam ring 5 and the adapter ring 4 by the seal member 7 and the pin 6.
Note that the volumes of the first pressure chamber 8 and the second pressure chamber 9 change according to the rotation position of the cam ring 5.
[0004]
A rotor 10 is provided inside the cam ring 5. The rotor 10 is fixed to a drive shaft 11 linked to an engine (not shown). Therefore, when the engine is operated to rotate the drive shaft 11, the rotor 10 rotates integrally with the drive shaft 11.
Further, a plurality of slits 12 are formed in the rotor 10, and a vane 13 is incorporated in each slit 12. These vanes 13 are installed so as to be able to protrude and retract in the radial direction, and protrude from the slits 12 when a centrifugal force acts by the rotation of the rotor 10. Then, a plurality of pump chambers 14 are formed between the vanes 13 by pressing the tips of the vanes 13 against the inner periphery of the cam ring 5.
[0005]
Since the inner circumference of the cam ring 5 is eccentric with respect to the drive shaft 11, when the rotor 10 rotates together with the drive shaft 11, the volume of each pump chamber 14 changes with this rotation. Then, the pump chamber 14 whose volume increases in response to the rotation is set as the suction side, and the operating oil is sucked into the expanding pump chamber 14. Further, the pump chamber 14 whose volume is reduced with rotation is set as a discharge side, and hydraulic oil is discharged from the reduced pump chamber 14. In FIG. 6, when the rotor 10 rotates to the left, the pump chamber 14 located in the range from the upper right to the upper left is the suction side, and the pump chamber 14 located in the range from the lower left to the lower right is the discharge side. It becomes.
[0006]
As shown in FIG. 5, a cover 20 is fixed to the mating surface of the body 1, and the cover 2 closes the bore 2. The distal end of the drive shaft 11 is inserted into a support hole 65 formed in the cover 20, and the drive shaft 11 is rotatably supported by a bearing 15 incorporated in the inner periphery of the support hole 65.
A high-pressure recess 16a and a low-pressure recess 17a are formed on the mating surface of the cover 20. A high-pressure recess 16b and a low-pressure recess 17b are also formed on the mating surface of the side plate 3 facing the high-pressure recess 16a and the low-pressure recess 17a. The high-pressure recess 16a and the high-pressure recess 16b face each other, and the low-pressure recess 17a faces the low-pressure recess 17b.
[0007]
As shown in FIG. 6, the high-pressure recess 16b is provided below the drawing where the pump chamber 14 on the discharge side is located. Therefore, the pressure oil discharged from the discharge-side pump chamber 14 is guided to the high-pressure recess 16b, and the pressure oil guided to the high-pressure recess 16b is transferred to the high-pressure passage formed in the side plate 3 as shown in FIG. The pressure is supplied to the high-pressure chamber 28 via 18.
On the other hand, the low-pressure recess 17b is provided on the upper side of the drawing where the suction-side pump chamber 14 is located. Therefore, the working oil guided to the low-pressure recess 17 a through the low-pressure passage 19 from the suction port 21 formed in the cover 20 is sucked into the suction-side pump chamber 14.
[0008]
The body 1 incorporates an opening adjustment mechanism A. As shown in FIG. 8, the opening adjustment mechanism A communicates one of the mounting holes 22 formed in the body 1 with a third fluid chamber 31 defined by the adapter ring 4 and the bore 2. The other of the mounting holes 22 is opened to the outside, and the opening is closed by a cylindrical cap 25.
An annular recess 25 a is formed on the outer periphery of the cap 25, and a first fluid chamber 29 is formed between the annular recess 25 a and the mounting hole 22. As shown in FIG. 7 which is a sectional view taken along line VII-VII in FIG. 6, the first fluid chamber 29 communicates with the high-pressure chamber 28 via a second discharge passage 36. The first fluid chamber 29 communicates with a second fluid chamber 30 in the cap 25 via a throttle hole 25b formed in the cap 25.
[0009]
Further, the control plunger 23 is slidably incorporated in the cap 25. A flow hole 32 is formed at the distal end side of the control plunger 23, and the second fluid chamber 30 and the third fluid chamber 31 communicate with each other through the flow hole 32.
Therefore, the pressure oil guided from the high pressure chamber 28 is guided to the first fluid chamber 29 → the throttle hole 25b → the second fluid chamber 30 → the flow hole 32 → the third fluid chamber 31. The pressure oil guided to the third fluid chamber 31 is guided to a discharge port 34 via a first discharge passage 33 formed in the body 1.
FIG. 10 is a schematic view of this conventional vane pump, and the same components are denoted by the same reference numerals. As shown in this figure, the discharge oil in the high-pressure chamber 28 is supplied to the power steering device PS via the second discharge passage 36 → the throttle hole 25b → the first discharge passage 33 → the discharge port 34.
[0010]
In addition, a feedback pin 26 is provided on the tip side of the control plunger 23. The feedback pin 26 passes through a hole 27 formed in the adapter ring 4. On the other hand, a spring 35 is incorporated in the second fluid chamber 30, and the elastic force of the spring 35 acts on the control plunger 23. When the feedback pin 26 is pressed by the tip of the control plunger 23, the elastic force of the spring 35 acts on the cam ring 5 via the feedback pin 26.
By reducing the clearance between the feedback pin 26 and the hole 27, the third fluid chamber 31 and the second pressure chamber 9 are prevented from communicating with each other through the gap between the feedback pin 26 and the hole 27. I have.
[0011]
The cam ring 5 against which the feedback pin 26 is pressed rotates leftward in the drawing with the pin 6 as a fulcrum, and its left outer peripheral surface is pressed against the inner periphery of the adapter ring 4. When the cam ring 5 is pressed against the adapter ring 4 in this manner, the amount of change in the volume of the pump chamber 14 becomes maximum, and the flow rate discharged from the discharge-side pump chamber 14 becomes maximum.
When the cam ring 5 is at the leftmost position in this way, the control plunger 23 also keeps moving to the leftmost position, and the opening of the throttle hole 25b becomes maximum. That is, when the cam ring 5 is at the leftmost position, as shown in FIG. 10, the opening degree of the throttle in the flow path connecting the high-pressure chamber 28 and the power steering device PS is maximized.
[0012]
When the cam ring 5 rotates rightward about the pin 6 from the above state, the feedback pin 26 is pushed rightward, so that the control plunger 23 also moves rightward. When the control plunger 23 moves rightward, the throttle hole 25b is closed by the right end of the control plunger 23.
That is, the opening adjustment mechanism A controls the opening of the throttle hole 25b in accordance with the movement of the cam ring 5, that is, the amount of eccentricity of the cam ring 5 with respect to the drive shaft 11. The opening adjustment mechanism A also has a function of holding the initial position of the cam ring 5 as described above.
[0013]
On the other hand, as shown in FIG. 6, a control valve B for controlling the rotational position of the cam ring 5 is incorporated above the bore 2.
As shown in FIG. 9, the control valve B incorporates a spool 41 and a spring 42 in an assembly hole 40 formed in the body 1. The opening of the mounting hole 40 is closed by a cap 43, and the rod 43 a of the spool 41 is pushed by the cap 43, so that the initial spring force of the spring 42 acts on the spool 41.
[0014]
The spool 41 has a first land portion 38 and a second land portion 39, a first pilot chamber 49 is formed between the first land portion 38 and the cap 43, and the second land portion 39 and an assembling hole are formed. A second pilot chamber 50 is formed between the second pilot chamber 50 and the bottom of the first pilot chamber 40. A drain chamber 37 is formed between the first land 38 and the second land 39.
As shown in FIG. 10, the first pilot chamber 49 communicates with the high-pressure chamber 28 via a passage 61, and guides the discharge pressure of the high-pressure chamber 28 to the first pilot chamber 49.
[0015]
The discharge port 34 communicates with the second pilot chamber 50 via a pilot passage 47. The load pressure of the power steering device PS connected to the discharge port 34 is led to the second pilot chamber 50 via the pilot passage 47.
Further, a drain port 48 communicates with the drain chamber 37 shown in FIG. 9, and the drain chamber 37 communicates with the tank T through the drain port 48.
Further, a drain annular groove 44 and a throttle groove 46 are formed in the first land portion 38, and the drain annular groove 44 and the drain chamber 37 are communicated via the throttle groove 46.
[0016]
A first passage 51 communicates with the mounting hole 40. The first passage 51 communicates with the first pressure chamber 8 via a first through hole 63 formed in the adapter ring 4 as shown in FIG. Then, in the state shown in the drawing, the first pressure chamber 8 is communicated with the tank T via the first through hole 63 → the first passage 51 → the drain annular groove 44 → the throttle groove 46 → the drain chamber 37 → the drain port 48. ing.
[0017]
The second passage 52 is communicated with an annular groove 53 formed on the inner periphery of the mounting hole 40. The second passage 52 communicates with the second pressure chamber 9 via a second through hole 64 formed in the adapter ring 4, as shown in FIG.
The second pressure chamber 9 communicates with the high-pressure chamber 28 through a small hole 54 shown in FIG. 6 so that the pressure from the high-pressure chamber 28 is guided to the second pressure chamber 9. As shown, when the annular groove 53 is closed by the spool 41, the pressure in the second pressure chamber 9 is maintained at the same pressure as that of the high-pressure chamber 28.
[0018]
When the second pressure chamber 9 is maintained at the same pressure as the high pressure chamber 28 and the first pressure chamber 8 is at the tank pressure, the left side of the cam ring 5 Keep pressed against the circumference. As described above, when the cam ring 5 is at the most left-turned position, the amount of change in the volume of the pump chamber 14 is maximum, and the discharge amount is also maximum.
The position of the cam ring 5 is controlled by the control valve B and the first and second pressure chambers 8 and 9 according to the discharge amount, and the operation will be described later.
[0019]
Further, a relief valve R is incorporated in the spool 41 of the control valve B as shown in FIG. The relief valve R regulates the maximum pressure of the power steering device PS connected to the discharge port 34. That is, the control valve B includes a seat member 55 incorporated in the spool 41, a ball 57 for blocking a passage 56 formed in the seat member 55, a guide member 58 for guiding the ball 57, And a spring 59 pressed against the member 55. Normally, the communication between the inside of the spool 41 and the passage 56 is blocked by the ball 57, but when the load pressure of the power steering device PS becomes equal to or higher than the pressure set by the spring 59, the ball 57 separates from the seat member 55. Accordingly, the second pilot chamber 50 communicates with the inside of the spool 41.
[0020]
When the second pilot chamber 50 communicates with the inside of the spool 41 in this manner, the load pressure of the power steering device PS is changed to the discharge port 34 → the pilot passage 47 → the second pilot chamber 50 → the passage 56 → the inside of the spool 41 → the spool 41. It is discharged to the tank T via the formed discharge hole 60 → drain chamber 37 → drain port 48.
Further, at this time, the spool 41 moves to the right in the drawing, whereby the first pilot chamber 49 communicates with the first pilot chamber 49 via the passage 61, and the second pressure chamber 9 communicates with the drain port 48. As a result, the pressure oil in the high pressure chamber 28 is supplied to the first pressure chamber 8 and the pressure oil in the second pressure chamber 9 is discharged to the tank T, so that the amount of eccentricity of the cam ring 5 decreases. As described above, the maximum pressure of the power steering device PS is controlled.
[0021]
Next, the operation of the conventional vane pump will be described.
First, when the rotor 10 is rotated by driving the engine, the vanes 13 project by centrifugal force, and a plurality of pump chambers 14 are formed. Then, at the upper position in FIG. 6, hydraulic oil is sucked into the suction-side pump chamber 14, and the hydraulic oil sucked into the pump chamber 14 is compressed as the rotor 10 rotates. Then, when the compressed pressure oil reaches the lower position from the pump chamber 14, it is discharged to the high pressure chamber 28 (see FIG. 5).
[0022]
The discharge oil discharged into the high-pressure chamber 28 is guided to the first fluid chamber 29 via the second discharge passage 36 (see FIG. 7). Then, as shown in FIG. 8, the power steering device is connected to the first fluid chamber 29 via the throttle hole 25b, the second fluid chamber 30, the circulation hole 32, the third fluid chamber 31, the first discharge passage 33, and the discharge port 34. Supplied to PS.
When the pressure oil discharged from the high-pressure chamber 28 is supplied to the power steering device PS in this way, a pressure difference occurs before and after the throttle hole 25b. Then, the pressure on the upstream side of the throttle hole 25b is guided to the first pilot chamber 49 of the control valve B via the passage 61, as shown in FIG. It is guided to the second pilot chamber 50 of the control valve B via 47.
[0023]
Accordingly, the thrust in the right direction in the drawing due to the pilot pressure in the first pilot chamber 49 and the thrust in the left direction in the drawing due to the pilot pressure in the second pilot chamber 50 and the elastic force of the spring 42 are applied to the spool 41 of the control valve B. Works. Then, the spool 41 moves to a position where these thrusts are balanced.
[0024]
Since the differential pressure before and after the throttle hole 25b is proportional to the flow rate passing through the throttle hole 25b, the differential pressure generated before and after the throttle hole 25b is small during low rotation with a small discharge amount. Therefore, the control valve B maintains the position shown in FIG. 10 by the spring 42, and at this time, the first pressure chamber 8 communicates with the tank, and the high pressure of the high pressure chamber 28 Guided through. That is, while the pump is rotating at low speed, the cam ring 5 maintains the illustrated maximum eccentric position.
Therefore, the flow rate discharged from the discharge port 34 increases with the rotation speed of the pump.
[0025]
When the pump speed increases from the above state and the pump discharge amount increases, the differential pressure across the throttle hole 25b also increases. When the rightward thrust acting on the spool 41 due to the differential pressure becomes larger than the initial elastic force of the spring 42, the spool 41 moves rightward. As a result, the first pilot chamber 49 communicates with the first passage 51, and the same pressure as the high pressure chamber 28 is introduced into the first pressure chamber 8 via the first passage 51 → the first through hole 63. At this time, the second pressure chamber 9 communicates with the drain port 48 via the second through hole 64 → the second passage 52 → the annular groove 53 → the notch 62 → the drain chamber 37.
Therefore, the cam ring 5 is rotated by a force generated by a pressure difference between the first pressure chamber 8 and the second pressure chamber 9 to a position where the spring force of the spring 35 of the opening adjustment mechanism A is balanced.
[0026]
As described above, when the cam ring 5 rotates rightward, the volume change rate of the pump chamber 14 decreases, and the displacement volume per rotation of the rotor 10 also decreases. Here, the discharge amount of the pump is obtained by multiplying the displacement volume per rotation of the rotor 10 by the number of rotations. Therefore, if the displacement per one rotation of the rotor 10 starts to decrease at the time when the rotation speed of the rotor 10 has increased to some extent, the discharge amount is kept constant. That is, when a predetermined discharge amount is reached, the eccentric amount of the cam ring 5 is adjusted to keep the discharge amount constant. The control of the eccentric amount of the cam ring 5 with respect to the discharge amount is performed by the control valve B, the first and second pressure chambers 8, 9 and the throttle hole 25b.
[0027]
After the discharge amount of the pump is stabilized as described above, when the rotation speed of the rotor 10 is further increased, the cam ring 5 further rotates rightward. Then, according to the rotation of the cam ring 5, the control plunger 23 of the position detecting mechanism A closes the throttle hole 25b. Therefore, the hydraulic oil supplied to the discharge port 34 via the throttle hole 25b is restricted. Further, when the opening degree of the throttle hole 25b is reduced, the pressure difference before and after the opening degree increases, whereby the spool 41 of the control valve B moves further rightward. Therefore, the cam ring 5 further rotates rightward, and the discharge amount further decreases.
[0028]
That is, in the above-described conventional example, if the rotation speed is in the low rotation range, the flow rate increases according to the rotation speed.However, if the flow rate is kept constant for a while after the predetermined rotation speed is exceeded, and the rotation speed further increases, This time, the flow rate control characteristic is set so as to reduce the flow rate.
[0029]
[Problems to be solved by the invention]
In the above conventional example, since the discharge amount is controlled without considering the load on the power steering device PS, energy loss may occur. For example, if the steering is not operated during straight running, the flow rate supplied to the power steering device PS is small. However, in the above-described conventional example, a predetermined flow rate control characteristic is always exhibited according to the number of revolutions, so that a predetermined flow rate is supplied to the power steering device PS even during straight running, and during low / medium speed running. As described above, when the ejection amount is large, a large energy loss occurs.
Therefore, in order to prevent this energy loss, it is conceivable to reduce the discharge amount by adjusting the position of the cam ring 5 when the power steering device PS is not used. For example, when the steering is not operated during straight running, turning the cam ring 5 rightward with the pin 6 as a fulcrum from the state shown in FIG. 10 reduces the discharge amount, thereby reducing energy loss. can do.
[0030]
However, if the flow rate is reduced by adjusting the position of the cam ring 5 as described above, there is a problem that an operation delay occurs in the power steering device PS when the steering is operated next time. That is, as described above, when the steering is operated while the cam ring 5 is rotated to the right to reduce the flow rate, the cam ring 5 rotates to the left, but the cam ring 5 moves to a predetermined position. It takes time to do it. Therefore, it takes time until a predetermined flow rate is supplied to the power steering device PS, which causes an operation delay in the power steering device PS. If an operation delay occurs in the power steering device, problems such as giving a sense of incongruity to the driver occur.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable displacement vane pump and a pressure supply device capable of preventing an operation delay of an actuator and reducing energy loss.
[0031]
[Means for Solving the Problems]
According to a first aspect of the present invention, a cam ring incorporated in a housing so as to be eccentric with respect to a drive shaft, a rotor incorporated inside the cam ring and rotating integrally with the drive shaft, and a rotor protruding and retracting in the rotor in a radial direction A plurality of vanes incorporated as possible, 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 throttle provided in the discharge passage And a cam ring control mechanism for controlling the amount of eccentricity of the cam ring in accordance with the flow rate discharged from the pump chamber, wherein the displacement of the rotor per rotation is varied by the amount of eccentricity of the cam ring. A branch passage branched from an upstream side of the throttle in the discharge passage, and a pressure-sensitive valve provided in the branch passage. When the load pressure is equal to or lower than the set pressure, the branch passage is connected to the suction side, and when the load pressure exceeds the set pressure, the branch passage is connected to the discharge passage downstream of the throttle. Features.
[0032]
According to a second aspect of the present invention, there is provided a variable discharge amount type pump in which a discharge amount is variably controlled by a regulator, a discharge passage connecting a discharge port of the variable discharge amount type pump to a load, and a throttle provided in the discharge passage. A branch passage branched from the upstream side of the throttle, and a pressure-sensitive valve provided in the branch passage. The pressure-sensitive valve is a variable discharge type pump when the load pressure of the actuator is equal to or lower than a set pressure. A branch passage is communicated with the suction side of the discharge passage, and when the load pressure exceeds a set pressure, the branch passage is communicated downstream of the throttle of the discharge passage.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
The first embodiment shown in FIGS. 1 to 3 is characterized in that a pressure sensitive valve F is provided. The basic structure of a variable displacement vane pump and the basic operation thereof are the same as those of the prior art. Same as in the example.
Therefore, the configuration and operation of the pressure sensitive valve F will be mainly described below, and the same components as those in the related art will be denoted by the same reference numerals, and detailed description thereof will be omitted.
In addition, the housing of this invention is comprised by the body 1 and cover 20 of this embodiment.
[0034]
As shown in FIG. 1, a third discharge passage 66 is connected to the second discharge passage 36 that guides the discharge oil, and the third discharge passage 66 communicates with the third fluid chamber 31.
A throttle 67 is provided in the third discharge passage 66, and a branch passage 68 is branched from an upstream side of the throttle 67.
The inflow port 69 of the pressure sensitive valve F is connected to the branch passage 68.
In the pressure-sensitive valve F, a spool 71 is slidably incorporated in a spool hole 70, and one end of the spool 71 is desired to be in the pilot chamber 72 and the other end is desired to be in the spring chamber 73. Then, the spring force of the spring 74 provided in the spring chamber 73 is applied to the spool 71 to maintain the illustrated normal position.
[0035]
When the spool 71 is at the normal position shown in the drawing, the pressure sensitive valve F as described above keeps the supply port 77 closed while the orifice 75 formed in the spool 71 opens to the return port 76.
Further, the return port 76 communicates with the low-pressure recess 17b via a return passage 78. The supply port 77 communicates with the first fluid chamber 29 via a merging passage 79.
[0036]
In the above-described state, when the pressure oil is discharged through the second discharge passage 36, a part of the pressure oil is guided to the passage 61 side, while almost all the flow rate flows to the third discharge passage 66 side and the branch passage. 68 side. At this time, the split ratio divided between the third discharge passage 66 and the branch passage 68 is determined by the opening area of the throttle 67 and the opening area of the orifice 75. In this embodiment, the opening area of the orifice 75 is set to be larger than the opening area of the restrictor 67 so that a larger flow rate than the third discharge passage 66 is supplied to the branch passage 68.
[0037]
The pressure oil guided to the third discharge passage 66 is supplied to the power steering device PS via the third fluid chamber 31 → the first discharge passage 33 → the discharge port 34. On the other hand, the pressure oil guided to the branch passage 68 is guided to the low-pressure recess 17 b via the inflow port 69 → the pilot chamber 72 → the orifice 75 → the return port 76 → the return passage 78. That is, a part of the discharge amount guided to the third discharge passage 33 and the branch passage 68 is supplied to the power steering device PS, and the remaining flow amount is returned to the suction side.
Assuming that the flow rate guided to the third discharge passage 66 is the standby flow rate Q1 and the flow rate guided to the branch passage 68 is the return flow rate Q2, the relationship between these flow rates Q1 and Q2 and the pump rotation speed is as shown in FIG. , As shown in FIG. The detailed description of these graphs will be described later.
[0038]
When the load pressure in the pilot chamber 72 increases from the state where the spool 71 is in the normal position, the thrust acting on the spool 71 in the right direction in the drawing increases. When this thrust is greater than the spring force of the spring 74, the spool 71 moves rightward. When the spool 71 moves in this manner, the orifice 75 closes and the supply port 77 opens. Therefore, the pressure oil distributed to the branch passage 68 side flows through the inflow port 69 → the pilot chamber 72 → the supply port 77 → the merge passage 79 → the first fluid chamber 29 → the throttle hole 25b → the second fluid chamber 30 → the flow hole 32. The fluid is guided to the third fluid chamber 31 through the third fluid chamber 31. Then, the pressure oil distributed to the branch passage 68 side joins with the pressure oil guided through the third discharge passage 66 in the third fluid chamber 31. That is, when the pressure sensitive valve F is switched, the entire discharge amount is supplied to the power steering device PS.
[0039]
Next, the operation of the first embodiment will be described. In this embodiment as well, the basic flow rate control characteristics are the same as those of the conventional example. That is, also in this embodiment, when the rotation speed is low, the flow rate increases in accordance with the rotation speed, and for a while after the predetermined rotation speed is exceeded, the flow rate becomes constant, and when the rotation speed becomes higher, Try to reduce the flow rate.
[0040]
For example, when the vehicle is traveling straight, and the power steering device PS requires almost no assisting force, the load pressure on the power steering device PS is also low. When the load pressure is low as described above, the pressure in the pilot chamber 72 of the pressure sensitive valve F is also low. This is because the load pressure of the power steering device PS is guided to the pilot chamber 72 via the discharge port 34 → the first discharge passage 33 → the third fluid chamber 31 → the third discharge passage 66 → the branch passage 68 → the inflow port 69. Because.
Therefore, in the pressure-sensitive valve F, the spool 71 maintains the illustrated normal position, and the branch passage 68 and the return passage 78 communicate with each other.
[0041]
When the branch passage 68 and the return passage 78 are communicated with each other by the pressure sensitive valve F, the pressure oil guided through the branch passage 68 returns to the suction side as the return flow rate B. The device PS is supplied with only the standby flow rate Q1. By doing so, it is possible to prevent energy loss due to flow resistance or the like that has conventionally occurred on the power steering device PS by the return flow rate Q2.
In the first embodiment as well, flow resistance occurs in the orifice 75 and the return passage 78, but this flow resistance is much smaller than the flow resistance generated in the power steering device PS. Therefore, as described above, according to the first embodiment, energy loss can be reduced.
[0042]
The relationship between the two flow rates Q1, Q2 and the pump speed is as shown in FIG. That is, the standby flow rate A and the return flow rate B increase proportionally until the pump reaches a predetermined rotation speed. However, when the pump rotation speed reaches the predetermined rotation speed, the function of the control valve B is exerted. Even if the number increases, each flow rate Q1, Q2 is kept constant.
The standby flow rate Q1 is set to a minimum flow rate that does not cause a response delay in the power steering device PS. That is, when the assisting force of the power steering device PS is not required, only the necessary minimum flow rate is supplied.
[0043]
When the steering wheel is steered from the above state, the load pressure on the power steering device PS increases. When the pressure sensitive valve F is switched by the load pressure, the return flow rate B is changed to the merging passage 79 → the first fluid chamber 29 → the throttle hole 25b → the second fluid chamber 30 → the communication hole 32 → the third fluid chamber 31 → The first discharge passage 33 is supplied to the power steering device PS via the discharge port 34. Therefore, when the pressure sensitive valve F is switched, the total flow rate of the standby flow rate Q1 and the return flow rate Q2 is quickly supplied to the power steering device PS. In this manner, the entire amount can be quickly supplied to the power steering device PS, so that a decrease in responsiveness can be prevented.
[0044]
When the steering wheel is being steered, the relationship between the standby flow rate Q1, the return flow rate Q2, and the pump speed is as shown in FIG. That is, the total flow rate of the standby flow rate A and the return flow rate B increases proportionally until the pump reaches a predetermined rotation speed, but when the pump rotation speed reaches the predetermined rotation speed, the total flow rate A + B is obtained by the function of the control valve B. Is kept constant. Then, when the pump speed further increases, the discharge amount decreases due to the function of the opening adjustment mechanism A.
[0045]
According to the first embodiment, when the power steering device PS is not used, only the standby flow rate A is supplied to the power steering device PS, and when the power steering device PS is used, the total flow of A + B is quickly supplied to the power steering device PS. Since the configuration is provided, it is possible to prevent a response delay of the power steering device PS while preventing energy loss.
[0046]
Further, since only the standby flow rate Q1 is supplied to the power steering device PS as described above, an effect of reducing the oil temperature in the power steering device PS can be expected. That is, when pressure oil is supplied to the power steering device PS, the temperature of the device itself increases due to pipe resistance. However, some types of vehicles are provided with a special cooling device such as an oil cooler to release the heat. However, as described above, if the temperature rise of the power steering device PS is suppressed by the oil temperature reduction effect by supplying only the minimum necessary pressure oil, a special cooling device such as an oil cooler becomes unnecessary. In other words, the oil temperature reduction effect can reduce not only the product cost but also the cost of the entire system.
[0047]
In the first embodiment, the variable displacement vane pump capable of changing the position of the cam ring 5 has been described. However, the present invention can also be applied to a device using a general variable displacement pump.
The second embodiment shown in FIG. 4 shows a pressure supply device using a pump capable of changing the discharge amount per rotation by a regulator.
[0048]
As shown in the figure, a power steering device PS is connected via a discharge passage 82 to a discharge port 81 of a variable discharge type pump p whose discharge amount is variably controlled by a regulator 80, and a throttle 83 is connected to the discharge passage 82. Is provided.
The branch passage 84 branches from the upstream side of the throttle 83 of the discharge passage 82, and a pressure sensitive valve F is connected to the branch passage 84.
[0049]
When the load pressure of the power steering device PS is equal to or lower than the set pressure, the pressure responsive valve F maintains the position shown in the drawing, and connects the branch passage 84 to the suction port of the variable discharge type pump p through the orifice 85 → the return passage 88. It communicates with 86. When the load pressure exceeds the set pressure, the pressure-sensitive valve F switches to the left position in the drawing, and the branch passage 84 communicates with the discharge passage 82 downstream of the throttle 83 through the merge passage 89.
Reference numeral 87 in the figure denotes a throttle mechanism that reduces the discharge amount when the variable discharge type pump reaches a predetermined number of revolutions, and corresponds to the opening degree adjusting mechanism A in the first embodiment. It is.
[0050]
According to the second embodiment, when almost no assisting force of the power steering device PS is required, the pressure sensitive valve F maintains the illustrated normal position, and connects the branch passage 84 and the return passage 88. Therefore, the pressure oil guided via the branch passage 84 returns to the suction port 86 of the variable discharge type pump p as the return flow rate Q2, so that the power steering device PS receives the pressure oil via the discharge passage 82 and the throttle 83. Only the standby flow Q1 is supplied. In this way, it is possible to prevent energy loss occurring on the power steering device PS side by the return flow rate Q2.
When the steering wheel is steered from the above state, the pressure sensitive valve F is switched by the increase in the load pressure on the power steering device PS side, and the return flow Q2 is supplied to the power steering device PS via the merge passage 89 → the discharge passage 82. Is done. When the pressure sensitive valve F is switched in this manner, the total flow rate of the standby flow rate Q1 and the return flow rate Q2 is quickly supplied to the power steering device PS, so that a decrease in responsiveness can be prevented.
[0051]
In the first and second embodiments, the apertures 67 and 83 are fixed apertures, but may be variable apertures. In this case, if the opening degree of the variable throttle is controlled by a solenoid or the like, the split ratio between the standby flow rate Q1 and the return flow rate Q2 can be set freely according to the control target or the like.
Further, in the first and second embodiments, the orifices 75 and 85 are provided in the load sensitive valve F. However, when the flow dividing ratio can be set only by the throttles 67 and 83, the orifices 75 and 85 are provided. It may be omitted.
Further, in the first and second embodiments, the load is the power steering device PS, but the load of the present invention is not limited to the power steering device. If the load fluctuates, the effect of the present invention of ensuring responsiveness while preventing energy loss can be expected.
In the first and second embodiments, the opening adjustment mechanism A and the aperture mechanism 87 are used. However, the opening adjustment mechanism A and the aperture mechanism 87 are not essential elements.
[0052]
【The invention's effect】
According to the first aspect, the pressure sensitive valve is provided in the branch passage branched from the upstream side of the throttle in the discharge passage, and when the load pressure is equal to or less than the set pressure, the branch passage is moved to the suction side. When the communication and the load pressure exceed the set pressure, the branch passage is configured to communicate with the discharge passage on the downstream side of the throttle, so that the operation loss of the actuator can be prevented and the energy loss can be reduced.
[0053]
According to the second aspect, when the pressure-responsive valve is at or below the set pressure of the actuator, the branch passage is connected to the suction side of the variable discharge type pump, and the load pressure exceeds the set pressure. Sometimes, the branch passage is connected to the downstream side of the throttle of the discharge passage, so that the energy loss can be reduced while preventing the operation delay of the actuator.
[Brief description of the drawings]
FIG. 1 is a sectional view of an embodiment.
FIG. 2 is a graph showing a relationship between a discharge flow rate and a pump rotation speed during non-steering.
FIG. 3 is a graph showing a relationship between a discharge flow rate and a pump speed during steering.
FIG. 4 is an overall explanatory diagram of a second 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.
[Explanation of symbols]
B. Control valve constituting cam ring control mechanism of the present invention
F Pressure sensing valve
Variable discharge pump
1 Body constituting housing of the present invention
5 Cam ring
8 First pressure chamber constituting cam ring control mechanism of the present invention
9 Second pressure chamber constituting cam ring control mechanism of the present invention
10 rotor
11 Drive shaft
13 Vane
14 pump room
20 Cover constituting housing of the present invention
33 1st discharge passage
36 Second discharge passage
66 Third discharge passage
67, 83 aperture
68, 84 Branch passage
75, 85 orifice
81 Discharge port
82 discharge passage
86 Suction port

Claims (2)

In the housing, a cam ring incorporated eccentrically with respect to the drive shaft, a rotor incorporated inside the cam ring and rotating integrally with the drive shaft, and a plurality of rotors incorporated in the rotor so as to be able to protrude and retract in the radial direction. A vane, 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, a throttle provided in the discharge passage, A variable displacement vane pump having a cam ring control mechanism for controlling the amount of eccentricity of the cam ring in accordance with the flow rate of the discharge, wherein the displacement of the rotor per rotation is varied by the amount of eccentricity of the cam ring. And a pressure-sensitive valve provided in the branch passage. The pressure-sensitive valve has a load pressure set therein. A variable capacity wherein the branch passage communicates with the suction side when the pressure is equal to or lower than the pressure, and the branch passage communicates with the discharge passage downstream of the throttle when the load pressure exceeds the set pressure. Type vane pump. A variable displacement pump whose discharge amount is variably controlled by a regulator, a discharge passage connecting a discharge port and a load of the variable discharge pump, a throttle provided in the discharge passage, and an upstream side of the throttle And a pressure-sensitive valve provided in the branch passage. When the load pressure of the actuator is equal to or lower than a set pressure, the pressure-sensitive valve is connected to the branch passage on the suction side of the variable discharge type pump. And a branch passage downstream of the throttle of the discharge passage when the load pressure exceeds a set pressure.

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