JP6251822B2 - Variable displacement vane pump - Google Patents

Description

  The present invention relates to a variable displacement vane pump applied to, for example, a hydraulic power steering device of an automobile.

  In general, a variable displacement vane pump includes a pump housing having a pump element housing portion therein, a pump element that is rotationally driven by an engine and sucks and discharges hydraulic fluid, and a hydraulic fluid discharged from the pump element to a supply destination. A discharge passage for guiding, an orifice provided in the middle of the discharge passage, and a flow rate control valve for controlling the discharge amount of the hydraulic fluid by the pump element based on the differential pressure before and after the orifice.

  The differential pressure before and after the orifice changes according to the discharge amount of the pump element, and this discharge amount is determined based on the rotational speed of the engine. That is, the variable displacement vane pump controls the flow rate of the hydraulic fluid based on the rotational speed of the engine.

  However, when such a variable displacement vane pump is applied to a vehicle power steering device, the hydraulic fluid is discharged to the power steering device even during straight traveling of the vehicle that requires little steering assist force by hydraulic pressure. As a result, energy loss may occur.

  Then, what was described in the following patent documents 1 is known as a variable displacement vane pump which can reduce energy loss at the time of attaching to the power steering device.

  In brief, the variable displacement vane pump described in the above publication is provided with a bypass passage connecting the upstream side and the downstream side of the orifice in addition to the above-described pump configuration, and provided in the bypass passage. A pressure sensitive valve that opens and closes the bypass passage based on a load pressure.

  The pressure-sensitive valve communicates the bypass passage during steering when the load pressure of the power steering device increases, while blocking the bypass passage when the load pressure is low. Thereby, since the pump discharge amount at the time of straight traveling can be reduced without being related to the engine speed, the energy loss of the power steering device can be reduced.

JP 2003-176791 A

  However, in the variable displacement vane pump, since the bypass path is provided, the flow path becomes complicated, and the apparatus may be forced to increase in size.

  The present invention has been devised in view of such technical problems, and provides a variable displacement vane pump that can suppress the increase in size of the device while reducing energy loss when applied to a power steering device. is there.

The present invention is a variable displacement vane pump that supplies hydraulic fluid to a power steering device of a vehicle, and includes a cylindrical portion and a bottom wall portion that is provided so as to close one end opening of the cylindrical portion. A first housing and a second housing provided so as to close the other end opening of the cylindrical portion, and a pump housing having a pump element accommodating portion between the two, and the pump housing A drive shaft that is rotatably supported by the shaft, and is housed in the pump element housing portion, a plurality of slits are formed in the circumferential direction, and the rotor is rotationally driven by the drive shaft; A vane provided in and out of the slit; an annular cam ring that is movably provided in the pump element housing portion and forms a plurality of pump chambers together with the rotor and the vane; A suction port that opens to a suction region of the plurality of pump chambers, the volume of which gradually increases as the rotor rotates. The rotor of the plurality of pump chambers that is provided in the pump housing. A discharge port that opens to a discharge region whose volume gradually decreases with rotation of the pump, a suction passage that is provided in the pump housing and supplies hydraulic fluid stored in a reservoir tank to the suction port, and is provided in the pump housing A discharge passage for supplying hydraulic fluid discharged from the discharge port to the outside of the pump housing and an outer peripheral side of the cam ring, and the cam ring moves in a direction in which the amount of eccentricity with respect to the rotor increases. The first fluid pressure chamber formed on the volume decreasing side, the second fluid pressure chamber formed on the volume increasing side, A first valve housing hole provided in the bottom wall of one housing and in the middle of the discharge passage; a suction pressure that is movably provided in the first valve housing hole and acts on one end side; and the discharge A first valve body that is controlled in movement based on a differential pressure with respect to a discharge pressure that is introduced from the passage and acts on the other end side, and that is provided in the pump housing, and that changes a flow passage cross-sectional area of the discharge passage with movement. A second valve housing hole formed at one end of the second valve housing hole, and a high pressure chamber formed so as to communicate with the discharge port. A control pressure chamber formed so as to communicate with the downstream side of the one valve housing hole, and movably provided in the second valve housing hole, and a differential pressure between the pressure of the high pressure chamber and the pressure of the control pressure chamber. Based on the first fluid pressure chamber for controlling the pressure of the first fluid pressure chamber. Two discs,
It is characterized by having.

  ADVANTAGE OF THE INVENTION According to this invention, the enlargement of an apparatus can be suppressed, reducing the energy loss at the time of applying to a power steering apparatus.

1 is a perspective view showing a variable displacement vane pump according to an embodiment of the present invention. It is a longitudinal cross-sectional view which shows the variable displacement vane pump. It is the sectional view on the AA line of FIG. It is a longitudinal cross-sectional view which shows the principal part of the variable displacement vane pump. FIG. 4A is an enlarged view of the main part of FIG. 4 showing a case where the differential pressure between the discharge pressure and the suction pressure acting on the first valve body is small, and FIG. 4B is an enlarged view of the main part of FIG. FIG. It is a perspective view showing the state where the 1st valve body concerning this embodiment was inserted in the front housing. The 1st valve body in this embodiment is shown, (A) is a perspective view of a 1st valve body, (B) is a side view of a 1st valve body. It is the BB sectional view taken on the line of FIG. It is a graph which shows the relationship between the pump rotation speed and the discharge flow rate in the variable displacement vane pump. It is a schematic diagram which shows the change rate of the flow-path cross-sectional area of the discharge passage accompanying the movement of a 1st valve body. It is a graph which shows the relationship between the spring load and displacement of an unequal pitch spring applicable as a coil spring which concerns on 2nd Embodiment of this invention. It is a graph which shows the relationship between the spring load and displacement of a taper spring applicable as a coil spring which concerns on the embodiment. It is a graph which shows the relationship between the pressure of this fluid pressure, and an orifice opening area when a pressure fluid is made to act on the 1st valve body which concerns on the embodiment. It is a longitudinal cross-sectional view which shows the principal part of the variable displacement vane pump which concerns on 3rd Embodiment of this invention.

  Hereinafter, each embodiment of the variable displacement vane pump according to the present invention will be described in detail with reference to the drawings. In each embodiment shown below, this variable displacement vane pump is shown attached to a power steering device of an automobile.

  As shown in FIGS. 1 to 3, the variable displacement vane pump 1 is housed in a pump housing 2 having a pump element housing chamber 2 a that is a cylindrical pump element housing portion, and in the pump element housing chamber 2 a. The pump element 3 is provided, and the pump element 3 is rotationally driven by a drive shaft 4 inserted through the pump element accommodation chamber 2a to perform pump operation.

  As shown in FIGS. 1 and 2, the pump housing 2 includes a front housing 5 that is a first housing formed in a bottomed cylindrical shape, and a rear housing that is a second housing that closes an opening of the front housing 5. And a housing 6, both of which are fixed together by a plurality of bolts 7.

  As shown in FIGS. 2 and 3, the pump element 3 includes a substantially annular adapter ring 8 fitted and fixed to the inner peripheral surface of the cylindrical portion 5 a of the front housing 5, and a substantially oval shape of the adapter ring 8. A substantially annular cam ring 9 movably provided in an internal space formed in a shape; a rotor 10 provided integrally with the drive shaft 4 on the inner peripheral side of the cam ring 9; and the front housing 5 and a substantially disk-shaped pressure plate 11 that sandwiches the cam ring 9 and the rotor 10 together with the rear housing 6.

  As shown in FIG. 3, the adapter ring 8 has a plate-like seal member 12 at the lower part of the inner peripheral surface 8a. The plate-like seal member 12 has a function of sealing between the adapter ring 8 and the cam ring 9 and serves as a rolling surface when the cam ring 9 moves in the internal space of the adapter ring 8. It has the function of

  Further, on the inner peripheral surface 8 a of the adapter ring 8, the position opposite to the plate-like seal member 12 in the radial direction is the same as the plate-like seal member 12 between the adapter ring 8 and the cam ring 9. A seal member 13 is provided for sealing.

  The cam ring 9 defines a first fluid pressure chamber 14 and a second fluid pressure chamber 15 between the cam ring 9 and the adapter ring 8 through the seal members 12 and 13. The amount of eccentricity relative to the rotor 10 is increased or decreased by moving in the left-right direction in FIG.

  Further, the cam ring 9 is constantly urged in a direction in which the amount of eccentricity with respect to the rotor 10 is maximized by a return spring 16 that elastically contacts the outer periphery thereof.

  Furthermore, the position of the cam ring 9 is located between the adapter ring 8 and the cam ring 9 and on the counterclockwise direction in FIG. 3 of the plate-like seal member 12, that is, on the second fluid pressure chamber 15 side. A position holding pin 17 is provided to hold the. The position holding pin 17 has a function of preventing rotation of the cam ring 9 relative to the adapter ring 8 in addition to a function of holding the position of the cam ring 9.

  When the drive shaft 4 is rotationally driven by an engine (not shown), the rotor 10 rotates in the counterclockwise direction (arrow direction) in FIG. A plurality of slits 18 extending in the radial direction are formed in the outer peripheral portion of the rotor 10 at substantially equal intervals in the circumferential direction, and substantially flat vanes 19 are formed through the slits 18. The rotor 10 is accommodated so as to be able to appear and retract in the radial direction.

  Each vane 19 is always urged toward the inner peripheral surface of the cam ring 9 by the pressure of hydraulic oil that is hydraulic fluid introduced into a back pressure chamber 20 formed on the inner peripheral side of the rotor 10 of each slit 18. It has come to be.

  Each of the vanes 19 forms a plurality of pump chambers 21 by partitioning an annular space between the cam ring 9 and the rotor 10 by two adjacent vanes 19 and 19.

  Further, in the inner end face 6a of the rear housing 6 facing the pump element accommodation chamber 2a, a portion corresponding to a suction region in which the volume of each pump chamber 21 gradually increases as the rotor 10 rotates is shown in FIG. As shown in FIG. 3, an arc-shaped first suction port 22 is formed. The first suction port 22 communicates with a reservoir tank T that stores hydraulic oil via a suction passage 23 formed in the rear housing 6. As a result, the hydraulic oil stored in the reservoir tank T flows through the suction passage 23 and is guided to the first suction port 22, and then the pump chambers 21 are caused by the pump suction action generated in the suction region. To be inhaled.

  Further, a second suction port 24 having substantially the same shape as the first suction port 22 is formed between the bottom surface of the front housing 5 and the one end surface 11a of the pressure plate 11 as shown in FIG. Yes. The second suction port 24 communicates with a seal ring groove 26 that is a seal member accommodating portion via a circulation passage 25 that is a low-pressure communication passage formed in the front housing 5.

  The seal ring groove 26 is formed in an annular shape on the outer peripheral side of the drive shaft 4 and accommodates therein a seal ring 27 that is a seal member for sealing between the front housing 5 and the drive shaft 4. Yes. As a result, the hydraulic oil transmitted from the pump element storage chamber 2a to the drive shaft 4 is restricted from leaking outside the pump housing 2, and the excess hydraulic oil is passed through the circulation passage 25. Thus, the refrigerant recirculates to the second suction port 24.

  Further, in one end surface 11a of the pressure plate 11, a portion corresponding to a discharge region in which the volume of each pump chamber 21 is gradually reduced as the rotor 10 rotates, as shown in FIGS. An arc-shaped discharge port 28 is formed. The discharge port 28 communicates with a pressure chamber 29 that is recessed in the bottom wall portion 5 b of the front housing 5. The pressure chamber 29 has a role of urging the pressure plate 11 toward the rotor 10 by internal pressure.

  2 and 3, the discharge port 28 supplies hydraulic oil to a rotary valve of a power steering device (not shown) through a discharge passage 30 formed in the bottom wall portion 5b of the front housing 5. To supply.

  The discharge passage 30 has a metering orifice 32 having a substantially circular cross section in the middle of the discharge passage 30, and the metering orifice 32 generates a differential pressure in the hydraulic oil.

  Further, as shown in FIGS. 2 and 3, a flow control valve 33 is disposed at the upper end of the front housing 5. The flow control valve 33 is slidable inside the control valve accommodation hole 34 and a control valve accommodation hole 34 which is a second valve accommodation hole provided in the front housing 5 so as to be orthogonal to the drive shaft 4. A control valve body 35 that is a second valve body housed in the plug, a plug 36 that closes an opening on one axial end side of the control valve housing hole 34, and the control valve body 35 toward the plug 36 side. And a valve spring 37 to be urged.

  As shown in FIG. 3, the control valve housing hole 34 is provided between the plug 36 and the control valve body 35 and introduces pressure (discharge pressure) upstream of the metering orifice 32. A high-pressure chamber 38, a control pressure chamber 39 provided on the other axial end side, which accommodates the valve spring 37 and into which pressure (control pressure) downstream of the metering orifice 32 is introduced; and the control valve body A low pressure chamber 41 formed on the outer peripheral side of 35 and into which the pump suction pressure is introduced from the suction passage 23 through the low pressure passage 40. These pressure chambers 38, 39 and 41 are separated by first and second land portions 35a and 35b of the control valve body 35, respectively.

  A damper orifice 42 is provided between the discharge passage 30 and the control pressure chamber 39 to reduce the influence of pulsation by lowering the fluid pressure of hydraulic oil introduced into the control pressure chamber 39. It has been.

  The control valve body 35 moves in the axial direction based on the differential pressure between the pressure in the high pressure chamber 38 and the pressure in the control pressure chamber 39.

  More specifically, when the pressure difference between the high pressure chamber 38 and the control pressure chamber 39 is relatively small and the control valve body 35 is positioned on the plug 36 side by the spring force of the valve spring 37, A communication passage 43 that communicates between the first fluid pressure chamber 14 and the control valve accommodation hole 34 opens into the low pressure chamber 41. As a result, the suction pressure is introduced into the first fluid pressure chamber 14 from the low pressure chamber 41.

  On the other hand, the pressure difference between the high pressure chamber 38 and the control pressure chamber 39 is relatively large, and the control valve body 35 resists the pressure of the control pressure chamber 39 and the urging force of the valve spring 37 to the right in FIG. When moved, the communication between the low pressure chamber 41 and the first fluid pressure chamber 15 is gradually cut off, and the high pressure chamber 38 is communicated with the first fluid pressure chamber 14 via the communication passage 43. As a result, high pressure is introduced into the first fluid pressure chamber 14 from the high pressure chamber 38.

  That is, the hydraulic pressure of the low pressure chamber 41 or the high pressure chamber 38 is selectively introduced into the first fluid pressure chamber 14.

  The pump suction pressure is always introduced into the second fluid pressure chamber 15, and when the suction pressure from the low pressure chamber 41 is introduced into the first fluid pressure chamber 14, Based on the urging force of the return spring 16, the cam ring 9 is disposed at a position where the eccentric amount with respect to the rotor 10 is maximized, and the pump discharge amount is maximized.

  On the other hand, when the high pressure of the high pressure chamber 38 is introduced into the first fluid pressure chamber 14, the cam ring 9 decreases in the amount of eccentricity against the biasing force of the return spring 16 based on the high pressure, that is, Rolling to the second fluid pressure chamber 15 side reduces the pump discharge amount.

  A relief valve 44 is formed inside the control valve body 35. The relief valve 44 is opened when the pressure in the control pressure chamber 39 exceeds a predetermined value, that is, when the load pressure on the power steering device side exceeds a predetermined value. The low-pressure chamber 41 and the low-pressure passage 40 are circulated to the suction passage 23.

  As shown in FIG. 4, the flow passage that reaches the downstream side of the metering orifice 32 in response to the load pressure on the power steering device side is located at a position immediately upstream of the metering orifice 32 in the discharge passage 30. A pressure sensitive valve 50 that changes the area is provided.

  As shown in FIG. 5 in particular, the pressure sensitive valve 50 includes a bottomed columnar pressure sensitive valve accommodating hole 51 which is a first valve accommodating hole formed in the bottom wall portion 5b of the front housing 5; A cylindrical pressure-sensitive valve body 52 (spool valve) which is a first valve body slidably accommodated inside the pressure-sensitive valve accommodation hole 51, and urges the pressure-sensitive valve body 52 toward the pressure plate 11 side. A coil spring 53 that is a spring member.

  As shown in FIGS. 4, 5, and 8, the pressure-sensitive valve housing hole 51 is formed in parallel with the drive shaft 4 and has a stepped diameter, and is formed at one end opening side in the axial direction. A large-diameter hole 51a that accommodates the pressure-sensitive valve body 52, and a small-diameter hole 51b that is formed on the other end bottom side in the axial direction and accommodates the coil spring 53.

  An annular step surface 51c that is orthogonal to the axial direction is formed at the joint between the large-diameter hole 51a and the small-diameter hole 51b. The stepped surface 51c is configured to restrict the movement of the pressure-sensitive valve body 52 toward the small-diameter hole 51b when the amount of movement toward the small-diameter hole 51b is equal to or greater than a predetermined value. It functions as a stopper on the 51 side.

  Further, since the pressure-sensitive valve accommodating hole 51 is arranged in parallel with the drive shaft 4, the pressure-sensitive valve body 52 and the coil spring 53 are respectively along the axial direction of the drive shaft 4. It is supposed to move.

  Further, the pressure sensitive valve accommodating hole 51 communicates with the metering orifice 32 at a substantially central position in the axial direction of the large diameter hole 51a.

  Further, the pressure-sensitive valve housing hole 51 is formed so that the opening communicates with the discharge region indicated by a one-dot chain line in FIG. 6 and overlaps the discharge region in the circumferential direction of the drive shaft 4. Has been.

  As shown in FIGS. 7A and 7B, the pressure-sensitive valve body 52 is a so-called spool valve formed in a cylindrical shape, and is provided at one end in the axial direction, and the inner circumference of the large-diameter hole 51a. A land portion 54 slidably formed on the surface and a guide portion provided on the other axial end side and slidably formed on the inner peripheral surface of the large-diameter hole portion 51 a in the same manner as the land portion 54. 55 and a passage constituting portion 56 that is provided integrally with an outer end portion in the axial direction of the guide portion 55 and forms a flow path for introducing hydraulic oil into the pressure receiving chamber 63 described later.

  The coil spring 53 is formed so that the spring constant has a substantially linear characteristic.

  The land portion 54 is formed on an annular flat surface whose one end surface 54a is a stopper, and comes into contact with a step surface 51c which is a stopper on the pressure-sensitive valve accommodating hole 51 side, thereby further increasing the above-mentioned feeling. The movement of the pressure valve body 52 toward one end side is restricted.

  The guide portion 55 slides on the inner peripheral surface of the pressure-sensitive valve housing hole 51 together with the land portion 54 to guide the movement of the pressure-sensitive valve body 52 so that the pressure-sensitive valve body 52 is not rattling. It comes to suppress.

  The passage constituting portion 56 is formed in a cylindrical shape slightly smaller in diameter than the guide portion 55, and includes four passage grooves 57 that are groove portions at substantially 90 ° intervals in the circumferential direction. Each passage groove 57 is notched in the radial direction of the pressure-sensitive valve body 52 so that the cross-sectional shape is a relatively large rectangular shape. That is, one end portion of the pressure-sensitive valve body 52 leaves four projecting portions 58 having a substantially triangular cross section, and most of the circumferential direction is cut away.

  An annular groove 60 is formed in the outer peripheral surface of the small-diameter portion 59 between the land portion 54 and the guide portion 55 of the pressure-sensitive valve body 52. The annular groove 60 is cut out along the circumferential direction. The annular groove 60 has four communication holes 59a that communicate with the inside and the outside of the pressure-sensitive valve body 52 at approximately 90 ° intervals in the circumferential direction, and the pressure-sensitive valve body 52 is connected to each other through the communication holes 59a. It communicates with the inside of.

  In addition, a disk-shaped partition wall 61 is integrally formed at a portion of the pressure-sensitive valve body 52 on the one end side of the communication holes 59a. As shown in FIGS. 4, 5, and 8, the partition wall 61 has an internal space of the pressure-sensitive valve accommodating hole 51, and a suction pressure chamber 62 on one end side that is cut off from the discharge passage 30 and each passage. It communicates with the discharge passage 30 through the groove 57 and is separated from the pressure receiving chamber 63 on the other end side where the discharge pressure is introduced.

  As shown in FIGS. 5 and 8, the suction pressure chamber 62 communicates with the seal ring groove 26 through a low pressure introduction passage 64 formed in the bottom surface of the pressure sensitive valve accommodating hole 51. Low pressure (suction pressure) is introduced.

  Further, as shown in FIGS. 4, 5 and 8, a spring holding groove 65 which is a cylindrical spring holding portion is formed at one end portion of the pressure sensitive valve body 52 constituting the suction pressure chamber 62. . The spring holding groove 65 is composed of one end surface 61a of the partition wall 61 and an inner peripheral surface of the land portion 54. The spring holding groove 65 accommodates and holds a part of the coil spring 53 on the inner peripheral side, and at the groove bottom. One end face 61 a of the partition wall 61 is in elastic contact with one end portion of the coil spring 53. On the other hand, the other end of the coil spring 53 is elastically contacted with the bottom surface of the pressure-sensitive valve accommodating hole 51 (small diameter hole 51b). As a result, the coil spring 53 urges the pressure-sensitive valve body 52 toward the pressure plate 11 as described above.

  The pressure receiving chamber 63 is formed on the inner peripheral side of the pressure-sensitive valve body 52 and on the other end side of the partition wall 61, and is introduced from the passage constituting portion 56 as indicated by an arrow in FIG. After applying pressure to the other end surface 61 b of the partition wall 61, the pressure fluid is led out downstream of the metering orifice 32 through the communication holes 59 a and the annular groove 60.

  The pressure sensitive valve body 52 moves in the axial direction based on the differential pressure between the pressure in the pressure receiving chamber 63 and the pressure in the suction pressure chamber 62, and accordingly, the metering orifice 32 is moved by the outer peripheral surface of the land portion 54. The channel cross-sectional area is changed by closing a part of the channel.

  More specifically, when the pressure difference between the pressure receiving chamber 63 and the suction pressure chamber 62 is relatively small, the pressure-sensitive valve body 52 is moved by the biasing force of the coil spring 53 as shown in FIG. The protrusions 58 and the pressure plate 11 are disposed at positions on the left side in the drawing. In this case, since the land portion 54 closes substantially half of the metering orifice 32, the cross-sectional area of the metering orifice 32 is almost halved.

  On the other hand, as shown in FIG. 5B, when the pressure difference between the pressure receiving chamber 63 and the suction pressure chamber 62 increases and the pressure sensitive valve body 52 overcomes the urging force of the coil spring 53 and moves to the right side in the figure. The overlap amount between the metering orifice 32 and the land portion 54 gradually decreases, and the flow passage cross-sectional area gradually increases accordingly. When the one end surface 54a of the land portion 54 and the stepped surface 51c of the pressure sensitive valve accommodating hole 51 are in contact with each other, the overlap amount is 0 and the flow path cross-sectional area is maximized. .

The pressure-sensitive valve body 52 is an opening portion of the pressure-sensitive valve housing hole 51 with respect to the pressure-sensitive valve housing hole 51 in which the coil spring 53 is incorporated when the variable displacement vane pump 1 is assembled. After being inserted from the side (the large-diameter hole 51a side) toward the bottom side, it is assembled by being closed by the pressure plate 11.
[Effects of this embodiment]
Therefore, according to this variable displacement vane pump 1, for example, during straight running that does not require steering assist force, most of the hydraulic oil supplied to the rotary valve (not shown) is used for steering assist. Therefore, the load pressure on the power steering device side is low. Accordingly, since the fluid pressure of the hydraulic oil in the discharge passage 30 communicating with the power steering device is kept low, the metering orifice 32 is blocked by the pressure-sensitive valve body 52 (land portion 54). The amount is large and the cross-sectional area of the flow path is small. That is, the state is the same as when the amount of restriction in the variable orifice is increased.

  For this reason, since the differential pressure between the fluid pressure upstream of the metering orifice 32 and the fluid pressure downstream is increased, the flow control valve 33 senses this and the amount of eccentricity of the cam ring 9 with respect to the rotor 10 decreases. By rolling in the direction, the pump discharge amount decreases as shown by the broken line in FIG.

  On the other hand, at the time of steering that requires a steering assist force, the hydraulic oil supplied to the rotary valve (not shown) is not circulated to the reservoir tank T but supplied to the inside of the power cylinder which is a closed space. The load pressure on the power steering device side increases.

  Then, since the fluid pressure of the hydraulic oil in the discharge passage 30 also increases with this, the pressure-sensitive valve body 52 (land portion 54) moves to the one end side in the axial direction (see FIG. 5B). The blocking amount of the metering orifice 32 is small, and the flow path cross-sectional area is large. In other words, the throttle in the variable orifice is loosened.

  For this reason, since the differential pressure between the fluid pressure upstream of the metering orifice 32 and the fluid pressure downstream is reduced, the flow control valve 33 senses this and the amount of eccentricity of the cam ring 9 with respect to the rotor 10 increases. By rolling in the direction, the pump discharge amount increases as shown by the solid line in FIG.

  Therefore, the discharge amount of the hydraulic oil supplied to the power steering device is maintained at a relatively large amount as shown by the solid line in FIG. 9 during steering.

  By the way, various configurations such as the pump element 3, the suction passage 23, and the discharge passage 30 are provided inside the variable displacement vane pump 1 as in the present embodiment, making it difficult to provide a new configuration. ing.

  Here, a region C as shown by a two-dot chain line in FIG. 4 is given as a portion where the configuration is not internally provided. Since the drive shaft 4 is inserted into the region C, It is necessary to avoid interference. For this reason, it is a substantial dead space for a mechanism or the like with complicated operation, and in providing a new configuration, the overall size of the apparatus accompanying the external attachment of the mechanism or the enlargement of the pump housing 2 or the like is increased. It was forced to become.

  Therefore, in the present embodiment, by using the pressure-sensitive valve 50 that operates linearly, it is possible to obtain a discharge amount suitable for the power steering device while being able to be attached to a place that has become a dead space. did.

  In particular, in the present embodiment, the pressure sensitive valve 50 is provided so as to move along the axial direction of the drive shaft 4, so that interference with the drive shaft 4 can be avoided.

  Further, the pressure sensitive valve accommodating hole 51 is arranged so as to overlap the discharge region in the circumferential direction of the drive shaft 4. Thereby, since the flow path for guiding the discharge pressure to the pressure sensitive valve accommodating hole 51 can be shortened, further space saving can be achieved.

  In addition, since the pressure-sensitive valve body 52 is a spool valve and the flow passage cross-sectional area can be controlled only by changing the overlap amount between the land portion 54 and the metering orifice 32, the mechanism is complicated. Therefore, it is possible to suppress an increase in the size of the apparatus accompanying this.

  Therefore, according to the variable displacement vane pump 1 of the present embodiment, an increase in the size of the device can be suppressed while reducing energy loss when applied to the power steering device.

  Further, since the other end side of the pressure sensitive valve accommodating hole 51 is provided so as to communicate with the discharge region via each passage groove 57, the discharge pressure can be easily introduced.

  Further, in the present embodiment, when the fluid pressure of the hydraulic oil flowing through the discharge passage 30 is low, the land portion 54 closes almost half of the metering orifice 32 and the land pressure increases from here. The closed area of the metering orifice 32 by the portion 54 is gradually reduced.

  That is, when the change in the cross-sectional area of the flow path accompanying the movement of the pressure-sensitive valve body 52 is seen, as shown in FIG. Is larger and gradually decreases from this point toward the tip of the arrow Y. In other words, the rate of change of the cross-sectional area of the flow path gradually decreases as the pressure of the hydraulic fluid flowing through the discharge passage 30 increases due to the circular shape of the cross section of the metering orifice 32.

  As a result, the rate of change in the flow path cross-sectional area is large immediately after steering from straight travel, and the flow rate increases rapidly with this, so that the steering response can be improved. Further, immediately after returning to straight running after turning, the rate of change of the channel cross-sectional area is small, and the flow rate gradually decreases.

  In addition, since the pressure-sensitive valve body 52 is inserted from the opening side (the large-diameter hole 51a side) of the pressure-sensitive valve housing hole 51 and is closed by the pressure plate 11, the assembly is performed. Since a sealing member such as a sealing plug (plug) is not required, the cost can be reduced.

  Further, since the pressure sensitive valve accommodating hole 51 is provided close to the drive shaft 4, the connection with the seal ring groove 26 communicating with the suction region can be easily performed. As a result, the suction pressure can be introduced also in the suction pressure chamber 62 disposed at a location separated from the suction region.

  Further, since each passage groove 57 notched in the radial direction is provided in the passage constituting portion 56 of the pressure-sensitive valve body 52, the passage constituting portion 56 is in contact with the pressure plate 11. However, hydraulic oil can be introduced into the pressure receiving chamber 63 from each passage groove 57. In particular, since each passage groove 57 is formed so as to have a large opening area when introducing the hydraulic oil, the hydraulic oil can be taken in more efficiently.

  In the present embodiment, as described above, the one end surface 54a of the land portion 54 is formed as a flat surface, and this is brought into contact with the stepped surface 51c of the pressure-sensitive valve housing hole 51, whereby the pressure-sensitive valve body. The movement more than the predetermined to the one end side of 52 was controlled. Thereby, the problem that the said coil spring 53 is compressed too much and a linear characteristic changes can be avoided. Further, since the gap between the one end surface 54a of the land portion 54 and the stepped surface 51c of the pressure-sensitive valve accommodating hole 51 is sealed, the high-pressure side hydraulic oil is prevented from circulating to the low-pressure side, so that the pump Efficiency can be improved.

  Furthermore, in the present embodiment, the coil spring 53 can be prevented from falling by the spring holding groove 65 formed at one end of the pressure-sensitive valve body 52. Further, since the coil length of the coil spring 53 can be increased by the depth of the spring holding groove 65, a change in spring characteristics (linear characteristics) accompanying compression of the coil spring 53 can be further suppressed.

  Further, when considering the maximum load applied to the pressure-sensitive valve body 52, comparing the direction of expanding the area of the metering orifice 32 (right direction in FIG. 5) and the direction of reducing (left direction in FIG. 5), Since the discharge pressure of the discharge passage 30 rises to the relief pressure at the maximum, the load in the direction of expanding the metering orifice area is larger. That is, when the slidability of the pressure-sensitive valve body 52 deteriorates due to foreign matter or the like and is fixed, the pressure-sensitive valve body 52 is brought into contact with the one end surface 54 a of the land portion 54 and the step surface 51 c of the pressure-sensitive valve housing hole 51. There is a high possibility of sticking in contact. Since the flow path cross-sectional area is maximized in this state, the steering assist function is maintained only by the fact that the energy saving effect cannot be obtained even when the both 54a and 51c are fixed. Will be. As a result, continuity of safe operation is ensured.

Further, in the present embodiment, the pressure fluid flowing through the discharge passage 30 is directly led to the downstream side of the metering orifice 32 while applying pressure to the pressure-sensitive valve body 52. The flow path formed in the pump housing 2 can be simplified compared to a configuration in which a pressure fluid is applied to the pressure-sensitive valve body 52 via a different flow path to control the position of the pressure-sensitive valve body 52. As a result, the apparatus can be simplified.
[Second Embodiment]
11 to 13 show a second embodiment of the present invention. The basic configuration is the same as that of the first embodiment, but a spring having a non-linear spring constant (non-linear spring) is applied as the coil spring 53. .

  That is, the coil spring 53 according to the present embodiment is formed such that at least one of the design parameters such as the coil diameter, the pitch, and the wire diameter changes along the axial direction of the coil spring 53. Thus, the relationship between the spring load F and the displacement x from the natural length (hereinafter simply referred to as “displacement x”) is non-linear.

11 and 12 show the relationship between the spring load F and the displacement x in an example of the coil spring 53 provided in the present embodiment. FIG. 11 shows the pitch between one end side and the other end side. Different so-called two-stage pitch springs, FIG. 12 shows so-called tapered springs in which the coil diameter expands in a tapered shape from one end side to the other end side.
[Effects of Second Embodiment]
In the first embodiment, since the coil spring 53 has a linear characteristic, the pressure P of the pressure fluid acting on the pressure sensitive valve body 52 and the small diameter hole 51b side of the pressure sensitive valve body 52 are increased. The amount of movement is almost proportional. Therefore, the change characteristic of the opening area S of the metering orifice 32 (hereinafter simply referred to as “orifice opening area S”) as the pressure P increases is affected by the cross-sectional shape (circular shape) of the metering orifice 32. As the orifice opening area S changes from the minimum value S _min to the maximum value S _max, it changes most greatly at the beginning of the movement of the pressure-sensitive valve body 52, and gradually increases as the pressure P increases. It is uniquely determined so as to decrease (see the one-dot chain line in FIG. 13).

  On the other hand, in this embodiment, since the coil spring 53 has non-linear characteristics, the amount of movement of the pressure P and the pressure-sensitive valve body 52 toward the small-diameter hole 51b has a proportional relationship. Instead, the pressure-sensitive valve body 52 moves greatly in a specific pressure range, or conversely, the amount of movement becomes small.

  Then, the change characteristic of the orifice opening area S with the increase in the pressure P is greatly influenced not only by the cross-sectional shape (circular shape) of the metering orifice 32 but also by the spring characteristic of the coil spring 53. Will change. Thereby, the change characteristic of the orifice opening area S accompanying the increase in the pressure P can be an irregular characteristic as shown by the solid line in FIG.

  This change characteristic can be freely adjusted to some extent by changing the coil spring 53 to one having a different nonlinear characteristic.

Therefore, according to the present embodiment, since the basic configuration is the same, it is possible to obtain the same effect as the first embodiment, and to increase the pressure P by the coil spring 53 having a non-linear characteristic. Since the change characteristic of the orifice opening area S associated therewith can be easily adjusted to a desired value, the degree of tuning freedom can be improved.
[Third Embodiment]
FIG. 14 shows a third embodiment of the present invention. The basic configuration is the same as that of the first embodiment, but the configuration of the pump housing 2 is changed. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, as shown in FIG. 14, the pump housing 2 of the present embodiment includes a front housing 5 that is a first housing formed in a flat plate shape and a rear housing 6 that is a second housing formed in a bottomed cylindrical shape. And is composed of. And the opening part of the said rear housing 6 is obstruct | occluded by the inner end surface by the side of the rear housing 6 of the said front housing 5, and the pump element accommodation chamber 2a is formed in an inside.

  Further, along with the configuration change of the pump housing 2, the adapter ring 8 constituting the pump element 3 is adapted to be fitted and fixed to the inner peripheral surface of the cylindrical portion 6b of the rear housing 6, and The pressure plate 11 is arranged on the bottom wall portion 6 c of the rear housing 6 so as to sandwich the cam ring 9 and the rotor 10 together with the front housing 5.

  Further, the drive shaft 4 that is pivotally supported by the pump housing 2 has one end portion 4a on the front housing 5 side projecting to the outside of the pump housing 2, and a pulley 66 serving as a drive shaft transmission portion on the projecting portion. Is provided. The pulley 66 rotates the drive shaft 4 by transmitting the engine power transmitted via a belt (not shown) to the drive shaft 4.

  In addition, the flow control valve 33 according to the present embodiment is changed to the upper end portion of the cylindrical portion 6 b of the rear housing 6 in accordance with the configuration change of the pump housing 2.

  Furthermore, the location of the pressure sensitive valve 50 according to the present embodiment is also changed in accordance with the configuration change of the pump housing 2. That is, the pressure sensitive valve 50 according to the present embodiment has the pressure sensitive valve accommodating hole 51 in the middle of the discharge passage 30 and more than the rotor 10 in the axial direction of the drive shaft 4 of the front housing 5. It is arranged at a position on the pulley 66 side.

In addition, about the other structure and connection relation of the said flow control valve 33 and the pressure sensitive valve 50, since it is the same as that of 1st Embodiment, concrete description is abbreviate | omitted.
[Effects of Third Embodiment]
Therefore, in this embodiment as well, the basic configuration is the same as that of the first embodiment, so that the pressure sensitive valve 50 increases the pump discharge amount or the steering assist force during steering when a large steering assist force is required. It is possible to reduce the pump discharge amount during straight traveling that does not require the. Thereby, since the pump discharge amount is optimized according to the operation state, the energy loss related to the pump operation can be reduced.

  Also in this embodiment, the region C (see the two-dot chain line in FIG. 14) in the vicinity of the drive shaft 4 of the front housing 5 is the drive shaft 4 and an unillustrated bearing that supports the drive shaft 4. From the standpoint of avoiding interference with the mechanism, it is a substantial dead space for a mechanism or the like with a complicated operation. However, the pressure sensitive valve 50 has a simple configuration that operates linearly. Since the pressure sensitive valve 50 is provided, an increase in the size of the apparatus due to the provision of the pressure sensitive valve 50 can be suppressed.

  The present invention is not limited to the configuration of each of the embodiments described above, and the configuration can be changed without departing from the spirit of the invention.

  For example, in each of the above embodiments, the cross-sectional shape of the metering orifice 32 has been described as a circular shape. However, along with the movement of the pressure-sensitive valve body 52 due to the increase in the pressure of hydraulic fluid flowing through the discharge passage 30, the cross-sectional area of the flow path As long as the rate of change of the thickness gradually decreases, it may be formed in a cross-sectional shape.

  Further, although the pressure sensitive valve 50 has been described as changing the flow passage sectional area of the metering orifice 32 formed on the discharge passage 30, the metering orifice 32 is abolished and the discharge passage 30. You may comprise so that a flow-path cross-sectional area may be changed directly.

  Further, in each of the embodiments described above, the pressure fluid flowing through the discharge passage 30 is directly led to the downstream side of the metering orifice 32 while applying pressure to the pressure sensitive valve body 52. The pressure sensitive valve 50 is used as a pilot valve, a pilot flow path branched from the discharge passage 30 is further provided, and the pressure sensitive valve body 52 is moved by the pilot pressure of the pressure fluid flowing into the pilot flow path, thereby The flowing pressure fluid may be indirectly led to the downstream side of the metering orifice 32.

  In each of the above embodiments, the stopper for restricting the movement of the pressure-sensitive valve body 52 toward the one end side is the pressure-sensitive valve body 52 side (one end face 54a) and the pressure-sensitive valve housing hole 51 side (step surface 51c). However, the stopper may be provided in at least one of the pressure-sensitive valve body 52 and the pressure-sensitive valve accommodating hole 51.

  Further, although the cam ring 9 has been described as increasing or decreasing the amount of eccentricity with respect to the rotor 10 by rolling the upper end surface of the plate-like seal member 12, the cam ring 9 is movably provided in the pump element accommodation chamber 2a. However, the method is not limited to this, and, for example, the position holding pin 17 may be used as a rocking fulcrum, and the amount of eccentricity may be changed by rocking.

Claims (20)

A variable displacement vane pump for supplying hydraulic fluid to a power steering device of a vehicle,
A first housing having a cylindrical portion and a bottom wall portion provided to close one end opening of the cylindrical portion, and a second housing provided to close the other end opening of the cylindrical portion. A pump housing having a pump element accommodating portion inside the housing,
A drive shaft inserted into the pump housing and rotatably supported;
A rotor housed in the pump element housing portion, formed with a plurality of slits in the circumferential direction, and rotated by the drive shaft;
A vane provided so as to freely appear and disappear in the slit;
An annular cam ring which is movably provided in the pump element housing portion and forms a plurality of pump chambers together with the rotor and the vane;
A suction port provided in the pump housing and opening to a suction region where the volume of the plurality of pump chambers gradually increases with rotation of the rotor;
A discharge port that is provided in the pump housing and opens to a discharge region in which the volume gradually decreases with rotation of the rotor among the plurality of pump chambers;
A suction passage provided in the pump housing, for supplying hydraulic fluid stored in a reservoir tank to the suction port;
A discharge passage which is provided in the pump housing and supplies the working fluid discharged from the discharge port to the outside of the pump housing;
A first fluid pressure chamber provided on the outer circumferential side of the cam ring and formed on the side where the volume decreases when the cam ring moves in a direction in which the amount of eccentricity with respect to the rotor increases; and on the side where the volume increases A formed second fluid pressure chamber;
A first valve housing hole provided in the bottom wall portion of the first housing and in the middle of the discharge passage;
The movement is controlled based on the differential pressure between the suction pressure acting on one end side and the suction pressure acting on one end side and the discharge pressure acting on the other end side. A first valve body that changes a flow passage cross-sectional area of the discharge passage,
A second valve receiving hole provided in the pump housing;
A high-pressure chamber provided on one end side of the second valve housing hole and formed to communicate with the discharge port, and provided on the other end side and communicated with the downstream side of the first valve housing hole of the discharge passage. A control pressure chamber formed to
A second valve body that is movably provided in the second valve housing hole and controls the pressure of the first fluid pressure chamber based on a differential pressure between the pressure of the high pressure chamber and the pressure of the control pressure chamber;
A variable displacement vane pump characterized by comprising: The variable displacement vane pump according to claim 1,
The variable displacement vane pump, wherein the first valve body is provided so as to move along an axial direction of the drive shaft. The variable displacement vane pump according to claim 1,
The variable capacity vane pump, wherein the first valve housing hole is provided so that the opening side communicates with the discharge region. The variable displacement vane pump according to claim 3,
The variable displacement vane pump, wherein the first valve housing hole is provided so as to overlap the discharge region in a circumferential direction of the drive shaft. The variable displacement vane pump according to claim 4,
The variable displacement vane pump, wherein the first valve body is inserted from the opening side of the first valve housing hole. The variable displacement vane pump according to claim 4,
The pump housing is
A seal member housing portion that is formed in an annular shape on the outer peripheral side of the drive shaft, and that houses a seal member that seals between the pump housing and the drive shaft;
A low-pressure communication passage that communicates the seal member housing portion and the suction region;
A low-pressure introduction path communicating the one end side of the first valve accommodation hole and the seal member accommodation portion;
A variable displacement vane pump characterized by comprising: The variable displacement vane pump according to claim 1,
The variable valve characterized in that the first valve body is a spool valve having a land, and changing a cross-sectional area of the discharge passage by changing an overlap amount between the land and the discharge passage. Capacity type vane pump. The variable displacement vane pump according to claim 7,
A variable displacement vane pump, characterized in that a groove formed in a radial cutout is formed on the other end side of the first valve body. The variable displacement vane pump according to claim 7,
A spring member for urging the first valve body toward the other end;
The variable displacement vane pump characterized in that the first valve body has a stopper for restricting movement in one end side direction at one end. The variable displacement vane pump according to claim 9,
The spring member is a coil spring,
The variable displacement vane pump, wherein the first valve body has a spring holding portion that houses and holds a part of the spring member on one end side. The variable displacement vane pump according to claim 9,
The variable displacement vane pump, wherein the first valve body is formed such that the flow passage cross-sectional area is maximized when movement is restricted by the stopper. The variable displacement vane pump according to claim 7,
The discharge passage is formed such that the rate of change in the cross-sectional area of the flow passage gradually decreases as the discharge pressure acting on the other end of the first valve body increases. Vane pump. The variable displacement vane pump according to claim 1,
A spring member provided in the first valve housing hole and biasing the first valve body;
The variable displacement vane pump, wherein the spring member has a non-linear spring constant. The variable displacement vane pump according to claim 1,
The variable displacement vane pump characterized in that the first valve body directly leads the working fluid applied to the other end side to the downstream side. The variable displacement vane pump according to claim 1,
The variable capacity vane pump, wherein the first valve housing hole is provided so that a bottom side thereof communicates with the suction passage. A variable displacement vane pump for supplying hydraulic fluid to a power steering device of a vehicle,
A first housing formed in a flat plate shape; a tubular portion; and a bottom wall portion provided so as to close one end opening of the tubular portion, and the other end of the tubular portion by the first housing. A second housing in which the opening is closed, and a pump housing having a pump element accommodating portion inside the second housing;
A drive shaft inserted into the pump housing and rotatably supported;
A drive shaft transmitting portion that is provided in a portion of the drive shaft that protrudes outside the pump housing and transmits external power to the drive shaft;
A rotor housed in the pump element housing portion, formed with a plurality of slits in the circumferential direction, and rotated by the drive shaft;
A vane provided so as to freely appear and disappear in the slit;
An annular cam ring which is movably provided in the pump element housing portion and forms a plurality of pump chambers together with the rotor and the vane;
A suction port provided in the pump housing and opening to a suction region where the volume of the plurality of pump chambers gradually increases with rotation of the rotor;
A discharge port that is provided in the pump housing and opens to a discharge region in which the volume gradually decreases with rotation of the rotor among the plurality of pump chambers;
A suction passage provided in the pump housing, for supplying hydraulic fluid stored in a reservoir tank to the suction port;
A discharge passage which is provided in the pump housing and supplies the working fluid discharged from the discharge port to the outside of the pump housing;
A first fluid pressure chamber provided on the outer circumferential side of the cam ring and formed on the side where the volume decreases when the cam ring moves in a direction in which the amount of eccentricity with respect to the rotor increases; and on the side where the volume increases A formed second fluid pressure chamber;
A first valve housing hole provided at a position closer to the drive shaft transmission part than the rotor in the axial direction of the drive shaft in the first housing and provided in the middle of the discharge passage;
The movement is controlled based on the differential pressure between the suction pressure acting on one end side and the suction pressure acting on one end side and the discharge pressure acting on the other end side. A first valve body that changes a flow passage cross-sectional area of the discharge passage,
A second valve receiving hole provided in the pump housing;
A high-pressure chamber provided on one end side of the second valve housing hole and formed to communicate with the discharge port, and provided on the other end side and communicated with the downstream side of the first valve housing hole of the discharge passage. A control pressure chamber formed to
A second valve body that is movably provided in the second valve housing hole and controls the pressure of the first fluid pressure chamber based on a differential pressure between the pressure of the high pressure chamber and the pressure of the control pressure chamber;
A variable displacement vane pump characterized by comprising: The variable displacement vane pump according to claim 16,
The variable displacement vane pump, wherein the first valve body is provided so as to move along an axial direction of the drive shaft. The variable displacement vane pump according to claim 16,
The variable capacity vane pump, wherein the first valve housing hole is provided so that the opening side communicates with the discharge region. The variable displacement vane pump according to claim 18,
The variable displacement vane pump, wherein the first valve housing hole is provided so as to overlap the discharge region in a circumferential direction of the drive shaft. A variable displacement vane pump for supplying hydraulic fluid to a power steering device of a vehicle,
A first housing having a cylindrical portion and a bottom wall portion provided to close one end opening of the cylindrical portion, and a second housing provided to close the other end opening of the cylindrical portion. A pump housing having a pump element accommodating portion inside the housing,
A drive shaft inserted into the pump housing and rotatably supported;
A rotor housed in the pump element housing portion, formed with a plurality of slits in the circumferential direction, and rotated by the drive shaft;
A vane provided so as to freely appear and disappear in the slit;
An annular cam ring which is movably provided in the pump element housing portion and forms a plurality of pump chambers together with the rotor and the vane;
A suction port provided in the pump housing and opening to a suction region where the volume of the plurality of pump chambers gradually increases with rotation of the rotor;
A discharge port that is provided in the pump housing and opens to a discharge region in which the volume gradually decreases with rotation of the rotor among the plurality of pump chambers;
A suction passage provided in the pump housing, for supplying hydraulic fluid stored in a reservoir tank to the suction port;
A discharge passage which is provided in the pump housing and supplies the working fluid discharged from the discharge port to the outside of the pump housing;
A first fluid pressure chamber provided on the outer circumferential side of the cam ring and formed on the side where the volume decreases when the cam ring moves in a direction in which the amount of eccentricity with respect to the rotor increases; and on the side where the volume increases A formed second fluid pressure chamber;
A first valve housing hole provided in the bottom wall portion of the first housing and in the middle of the discharge passage;
The movement is controlled based on the differential pressure between the suction pressure acting on one end side and the suction pressure acting on one end side and the discharge pressure acting on the other end side. A first valve body for deriving hydraulic fluid that has acted on the other end side while changing the flow passage cross-sectional area of the discharge passage,
A second valve receiving hole provided in the pump housing;
A high-pressure chamber provided on one end side of the second valve housing hole and formed to communicate with the discharge port, and provided on the other end side and communicated with the downstream side of the first valve housing hole of the discharge passage. A control pressure chamber formed to
A second valve body that is movably provided in the second valve housing hole and controls the pressure of the first fluid pressure chamber based on a differential pressure between the pressure of the high pressure chamber and the pressure of the control pressure chamber;
A variable displacement vane pump characterized by comprising:

Images