JP4476175B2 - Vane pump - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vane pump as a pump used in a vehicle, in which a plurality of vanes are attached to an outer periphery of a rotor that is rotated by a drive shaft so that the vanes can be moved in and out in a radial direction.

  As a conventional vane pump, for example, a variable displacement type described in Patent Document 1 below is known.

  The variable displacement vane pump includes a rotor in which a plurality of vanes can be projected and retracted in a radial direction, a cam ring swingably provided on an outer peripheral side of the rotor, and both axial sides so as to sandwich the rotor. And a pump chamber is formed by the rotor, the vane and the cam ring when the vane comes into contact with the inner peripheral surface of the cam ring. Then, the rotor is rotated, and the pump is operated by continuously discharging hydraulic oil in the pump chamber.

The first plate member is provided with a discharge-side vane back pressure groove that overlaps the base end portion of the vane in the discharge region. The discharge side vane back pressure groove and the discharge passage are communicated with each other through the orifice passage, and the discharge pressure is introduced into the discharge side vane back pressure groove, thereby increasing the amount of hydraulic oil on the base end side of the vane. The power of jumping out is secured. In addition, when the vane is pushed into the rotor slot along the cam ring, the pressure on the discharge side vane back pressure groove side with respect to the orifice passage is increased, and the vane pop-out property is improved.
JP-A-7-259754 (FIG. 1)

  However, in the variable displacement type vane pump, when the vane immediately after starting the pump is not sufficiently ejected from the rotor, less hydraulic oil is introduced from the discharge passage into the discharge side vane back pressure groove, and the vane follows the cam ring. Since the amount pushed into the slot of the rotor is small, the pressure on the discharge side vane back pressure groove side cannot be sufficiently increased, and there is a possibility that sufficient ejection of the vane cannot be secured promptly.

  The present invention has been made paying attention to such a problem, and provides a vane pump that can quickly ensure sufficient ejection of vanes and improve pump efficiency.

The invention according to claim 1 is a pump body, a drive shaft pivotally supported by the pump body, a rotor provided in the pump body and driven to rotate by the drive shaft, and a circumferential direction of the rotor provided in a plurality, and a slot which is formed to extend from the bottom radially outward, each having an inner end portion in the radial direction, a vane provided freely each infested 該Su lot, is formed in a circular ring A cam ring that is swingably provided in the pump body and that forms a plurality of pump chambers together with the rotor and the vane when the vane abuts on an inner peripheral surface, and a cam ring that is provided on both axial sides of the cam ring. A plurality of pump chambers provided on at least one side of a first plate member and a second plate member, and the first plate member or the second plate member; A suction port in which the volume is open to the suction area increases, before SL provided in the second plate member, and a discharge port volume of the plurality of pump chambers are open to the ejection region to reduce, provided in the pump body, A pressure chamber into which hydraulic oil discharged from the discharge port is introduced; a discharge passage provided in the pump body for discharging the hydraulic oil introduced into the pressure chamber to the outside of the pump body; and the first plate A suction side vane back pressure groove that is provided in a member and is formed so as to open to the bottom of the slot in the suction region of the rotor, and that communicates with the bottom of the slot in the suction region; and provided in the first plate member. The suction vane back pressure groove is divided and formed so as to open to the bottom of the slot over the entire discharge region of the rotor. Is the the discharge-side vane back pressure groove which communicates the slot bottom portions in the discharge region, the introduction passage for supplying the hydraulic fluid discharged from the pump chamber in the discharge region to the discharge side vane back pressure groove, wherein From a terminal portion provided on the second plate, which is a rear end portion of the discharge region in the rotor rotation direction from a start end portion which is a front end portion of the discharge region in the rotor rotation direction toward the rotor rotation direction. It is formed over a predetermined angle close to the start end side and is formed so as to open to the slot bottom of the rotor, and the hydraulic oil in the discharge side vane back pressure groove passes through the bottom of the slot. The start end side vane back pressure groove and the start end side vane back pressure groove that are formed in the start end side vane back pressure groove and discharge the working oil in the start end side vane back pressure groove to the pressure chamber. A passage,
The starting end side orifice passage is formed so that the opening area becomes smaller as the vane is pushed into the slot at a position where the starting end side orifice passage and the slot of the rotor overlap. .

  According to this invention, when the vane at the time of starting the pump does not jump out of the slot, the opening area of the starting end side orifice passage is reduced by the vane, that is, the hydraulic oil discharged from the starting end side orifice passage is reduced. Therefore, even if the oil flow rate is small, the pressure in the start end side vane back pressure groove can be sufficiently increased. As a result, other vanes that have not popped out can be popped out, and sufficient pump operation can be performed from the start of the pump.

The invention according to claim 2 is provided in the second plate member, and the termination is performed from the start end side vane back pressure groove toward the direction opposite to the rotation direction of the rotor from the termination portion side of the discharge region. A terminal portion that is formed only over a predetermined angle closer to the portion side, is formed so as to open to the slot bottom portion of the rotor, and the working oil of the discharge side vane back pressure groove is introduced through the slot bottom portion Side vane back pressure groove,
An opening is formed in the terminal end side vane back pressure groove, and a terminal end side orifice passage for discharging hydraulic oil in the terminal end side vane back pressure groove to the pressure chamber is provided .

  According to the present invention, when the inside of the pump is in a high temperature and high pressure state, the hydraulic pressure is insufficient in the vane back pressure groove that causes the vane to jump out by flowing out the hydraulic oil from each vane back pressure groove at the end of the discharge stroke. However, it is difficult for the vane to jump out. However, by introducing hydraulic oil into the terminal-end-side vane back pressure groove through the terminal-end-side orifice passage, it is possible to make up for the shortage of hydraulic pressure and cause the vane to jump out.

The invention described in claim 3 is characterized in that the start end side vane back pressure groove is formed in an arc shape and is formed radially outward from the vane back pressure groove in the discharge region .

  According to the present invention, the start end side vane back pressure groove and the opening of the slot by the vane are formed by forming the start end side vane back pressure groove opening the start end side orifice passage radially outside the vane back pressure groove. The increase / decrease width of the area can be increased. As a result, the oil pressure of the discharge side vane back pressure groove can be more effectively improved, so that the vane pop-out property can be ensured more reliably.

  Hereinafter, an embodiment in which a vane pump according to the present invention is applied to a variable displacement type will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the variable displacement vane pump is fixed to a pump housing 1, a drive shaft 2 rotatably supported by the pump housing 1, and an outer peripheral side of the drive shaft 2. In addition, an annular rotor 3 in which a plurality of slots 3a are formed in the circumferential direction, and first and second plate members 4, 5 provided on both sides in the axial direction so as to sandwich the rotor 3; A rear plate 6 provided so as to be in close contact with the first plate member 4, a flat plate-like vane 7 provided so as to be able to protrude and retract in the slot 3 a, and the rotor 3. And a cam ring 8 in sliding contact.

  The pump housing 1 includes a housing body 10 in which a recess 10a for accommodating the rotor 3 is formed, and a rear cover 11 that is coupled to the housing body 10 and closes the recess 10a.

  Since the cam ring 8 is provided eccentrically with respect to the rotation center of the rotor 3, the rotor 3 rotates counterclockwise in the figure and the tip of the vane 7 is slidably contacted with the inner peripheral surface of the cam ring 8. Then, the capacity of the pump chamber formed between the adjacent vanes 7 and 7 is increased or decreased, thereby continuously performing the pump operation. When the amount of eccentricity between the cam ring 8 and the rotor 3 changes, the volume change rate of the pump chamber changes, and the pump capacity changes accordingly.

  An adapter ring 14 that forms a housing space for the cam ring 8 is fitted inside the recess 10 a of the housing body 10, and the outer peripheral surface of the cam ring 8 slides on the inner peripheral surface of the adapter ring 14. However, the cam ring 8 swings in the adapter ring 14.

  The adapter ring 14 is formed in an approximately elliptical shape so that the inner peripheral surface thereof allows the cam ring 8 to swing. A cam ring support plate 15 serving as a swing center of the cam ring 8 is provided on the lower end side of the inner peripheral surface of the adapter ring 14. The cam ring 8 is supported by the cam ring support plate 15, so that the adapter ring The free rotation within 14 is restricted.

  A seal member 16 is provided along the axial direction of the rotor 3 at a position facing the cam ring support plate 15 on the inner peripheral surface of the adapter ring 14, and the cam ring support plate 15 swings the cam ring 8. While permitting, it is in close contact with the outer peripheral surface of the cam ring 8.

  A space formed between the cam ring 8 and the adapter ring 14 is divided into a first working chamber 18 on the left side in FIG. 2 and a second working chamber 19 on the right side in FIG. 2 by the cam ring support plate 15 and the seal member 16. It is divided into.

  A through hole 20 is formed in the peripheral wall of the adapter ring 14 at a portion facing the second working chamber 19, and a coil spring 21 is interposed between the cam ring 8 and the pump housing 1 through the through hole 20. The coil spring 21 biases the cam ring 8 toward the first working chamber 18, and the cam ring 8 swings due to the balance between the pressure in the first working chamber 18 and the spring force of the coil spring 21. It has become. Note that one end of the coil spring 21 is supported by a covered cylindrical cap 22.

The pump housing 1 includes a suction passage 25 for introducing hydraulic oil from a tank (not shown) into a suction region (upper half region in FIG. 1) in the cam ring 8 and a discharge region (in FIG. 1). And a discharge passage 26 for supplying hydraulic oil from a lower half area) to a power cylinder (not shown).

  As shown in FIGS. 3 and 4, the first plate member 4 is formed with a first suction port 28, which is an arc-shaped groove, at a position serving as a suction region in the cam ring 8. Is directly connected to the suction passage 25. A suction side vane back pressure groove 29, which is also an arc-shaped groove, is formed on the inner peripheral side of the first suction port 28, and the bottom sides of the slots 3a communicate with each other.

  And the 1st discharge port 30 which is a circular-arc-shaped groove is formed in the position used as the discharge area | region of the 1st plate member 4. As shown in FIG. A discharge-side vane back pressure groove 31 that is also an arcuate groove is formed on the inner peripheral side of the first discharge port 30, and the bottom sides of the slots 3a are communicated with each other. In addition, a substantially elliptical discharge small groove 32 independent of the first discharge port 30 is formed at a position substantially on the same circumference as the first discharge port 30. The discharge small groove 32 communicates with the discharge side vane back pressure groove 31, and the hydraulic oil discharged from the discharge small groove 32 is introduced into the discharge side vane back pressure groove 31.

  On the other hand, as shown in FIGS. 3 and 5, the second plate member 5 is formed with a second suction port 33, which is an arcuate groove, at a position to be a suction region in the cam ring 8. A vane back pressure groove 34, which is also an arcuate groove, is formed on the inner peripheral side of the second suction port 33, and the bottom sides of the slots 3a are communicated with each other.

  A second discharge port 35 that is an arc-shaped groove is formed at a position that becomes a discharge region of the second plate member 5, and is directly connected to the discharge passage 26, and the second discharge port 35. Independently arcuate starting end side vane back pressure grooves 36 and terminal end side vane back pressure grooves 37 are formed at positions on the inner peripheral side of each.

  The start end side vane back pressure groove 36 is provided so as to overlap the start end side of the discharge side vane back pressure groove 31 of the first plate member 4, and is provided at the lower end side of the start end side vane back pressure groove 36. An opening end side orifice passage 38 communicating with the discharge passage 26 is formed. As shown in FIGS. 1 and 3, the starting end side orifice passage 38 communicates with the pressure chamber 41 via a passage 40 formed in the housing body 10, and discharges hydraulic oil to the pressure chamber 41. It is like that.

  On the other hand, the end portion side vane back pressure groove 37 is provided so as to overlap the end portion side of the discharge side vane back pressure groove 31 in the radial direction. A part-side orifice passage 39 is formed as an opening. The end portion side orifice passage 39 communicates with the pressure chamber 41 via a passage 42 formed in the housing body 10, and the hydraulic oil introduced into the end portion side vane back pressure groove 31 flows into the pressure chamber 41. It comes to leak.

  Here, the start end side vane back pressure groove 36 is provided so as to be substantially closed by the side surface of the base end portion of the vane 7 when the vane 7 is retracted most deeply into the slot 3a. When 7 is in sliding contact with cam ring 8, it is formed so as not to be blocked. That is, the opening area of the starting end side orifice passage 38 is changed depending on the amount of protrusion of the vane 7.

  The starting end side vane back pressure groove 36 is formed on the outer peripheral side of the discharge side vane back pressure groove 31 while overlapping with the discharge side vane back pressure groove 31 in the radial direction. It communicates with the discharge side vane back pressure groove 31 via the part side.

  As shown in FIG. 1, the rear plate 6 includes through holes communicating with the first suction port 28, the first discharge port 30, and the suction side vane back pressure groove 29, and the discharge small groove 32 and the discharge side. A groove-shaped introduction passage 43 that communicates with the vane back pressure groove 31 is formed, and the introduction passage 43 communicates with a storage chamber 44 formed in the rear cover 11. The hydraulic oil discharged from the discharge small groove 32 flows into the pressure chamber 41 through the storage chamber 44, the introduction passage 43, and the terminal end side orifice passage 39.

  The pressure in the first working chamber 18 is controlled by a control valve 48 that responds to a differential pressure across an orifice (not shown) provided in the discharge passage 26, and the first and second suction ports are provided in the second working chamber 19. The low pressure of the suction passage 25 is always introduced through 28 and 33.

  In the control valve 48, a bottomed cylindrical spool valve 50 is accommodated in a valve chamber 49 formed in the pump housing 1, and the inside of the valve chamber 49 is divided into a high pressure chamber 51 and a low pressure chamber 52 by the spool valve 50. Has been. The high-pressure chamber 51 communicates with the upstream portion of the orifice of the discharge passage 26, while the low-pressure chamber 52 communicates with the downstream portion of the orifice of the discharge passage 26. Accommodates a return spring 53 that biases the spool valve 50 toward the high-pressure chamber 51.

  A first pressure guiding passage 56 and a second pressure guiding passage 57 communicating with the first and second working chambers 18 and 19 are respectively formed at positions aligned in the longitudinal direction of the valve chamber 49. . The adapter ring 14 is also formed with first and second passage holes 58 and 59 communicating with the first and second pressure guide passages 56 and 57, and the high pressure chamber 51 is moved by moving the spool valve 50. The first working chamber 18, the low pressure chamber 52, and the second working chamber 19 are selectively communicated with each other.

  A low pressure passage 62 branched from the suction passage 25 is formed in the peripheral wall at the substantially center in the axial direction of the valve chamber 27. On the other hand, an annular groove 63 is formed on the outer periphery of the shaft portion of the spool valve 49 so that the low pressure passage 62 and the pressure guide passage 56 communicate with each other. When the spool valve 49 is displaced, for example, toward the low pressure chamber 52 from this state, the low pressure passage 62 and the first pressure guide passage 56 are communicated. Is designed to shut off.

  The opening of the first pressure guide passage 56 is gradually blocked by the protrusion of the spool valve 49, but the first pressure guide passage 56 gradually opens to the high pressure chamber 51. As a result, a pressure corresponding to the displacement of the spool valve 49 is created in the first pressure guiding passage 56, and the pressure is introduced into the first working chamber 18. That is, while the differential pressure across the orifice does not reach the set pressure, hydraulic oil is introduced into the first working chamber 18 from the low pressure passage 62 via the annular groove 63 and the first pressure guiding passage 56, and from this state When the differential pressure across the orifice (not shown) exceeds the set pressure, a pressure corresponding to the differential pressure across the orifice is introduced into the first working chamber 18.

  Hereinafter, the operation of the vane pump of this embodiment will be described. When the drive shaft 2 rotates counterclockwise by starting the engine, as shown in FIG. 2, in the initial state where the cam ring 8 is displaced to the maximum eccentric position by being biased by the coil spring 21, The rotor 3 rotates counterclockwise. As the rotor 3 rotates, the hydraulic oil sucked from the first suction port 28 via the suction passage 25 is pressurized by the vane 7 and discharged to the discharge passage 26 via the second discharge port 35. The hydraulic fluid discharged to the discharge passage 26 passes through the orifice and is supplied to a power cylinder (not shown) when the differential pressure across the orifice exceeds a set value, while the low pressure chamber 51 of the control valve 48 and the high pressure are supplied from the orifice. It is introduced into the chamber 52.

  Here, when the rotation of the drive shaft 2 is slow and the centrifugal force is small at the start of the pump, the vane 7 is difficult to jump out of the slot 3a of the rotor 3. In a state where the vane 7 does not protrude from the slot 3a, the vane 7 and the start end side vane back pressure groove 36 overlap with each other, so that the start end side orifice passage 38 formed in the start end side vane back pressure groove 36 The opening area is reduced. As a result, the pressure of the starting end side vane back pressure groove 36 can be sufficiently improved even with a small oil flow rate, and the pressure continuously pushes up the base end portion of the vane 7 to improve the pump efficiency. be able to.

  When the vane 7 is in sliding contact with the inner peripheral surface of the cam ring 8, the starting end side orifice passage 38 is fully opened, so that the pressure on the base end side of the vane 7 does not increase, and the vane 7 Can be prevented from increasing due to being pressed against the inner peripheral surface of the cam ring 8.

  Then, when the hydraulic oil in the pump becomes high temperature and high pressure after the pump is driven, the viscosity of the hydraulic oil becomes low, and thereby the discharge side vane back pressure groove 31 and the start end side vane back pressure groove 36. In addition, leakage from the end portion side vane back pressure groove 37 into the clearance around the drive shaft 2 communicating with the suction passage 25 causes the pressure in the end portion vane back pressure groove 37 to decrease, and the vane 7 to be pushed out insufficiently. However, the terminal end side vane back pressure groove 37 and the terminal end side orifice passage 39 are formed on the terminal end side of the discharge region, and are communicated with the discharge small groove 32, thereby being discharged from the discharge small groove 32. The hydraulic fluid thus introduced is introduced into the terminal end side vane back pressure groove 37 through the terminal end side orifice passage 39. Accordingly, the amount of hydraulic oil on the base end side of the vane 7 is increased and the pressure on the base end side is improved, so that the vane 7 can be ejected from the rotor 3.

  In addition, since the hydraulic oil introduced from the discharge small groove 32 is introduced into the terminal end side orifice passage 39 through the storage chamber 44, the turbulent flow of the hydraulic oil introduced into the terminal end side vane back pressure groove 37 is provided. The vane 7 can be pushed up smoothly.

  Furthermore, the start end side vane back pressure groove 36 in which the start end side orifice passage 38 is formed is formed radially outside the discharge side vane back pressure groove 31 formed in the first plate member 4. For example, the increase / decrease width of the opening area of the start end side orifice passage 38 by the vane 7 can be made larger than the start end side orifice passage 38 provided at the same radial position as the discharge side vane back pressure groove 31. As a result, the oil pressure of the discharge side vane back pressure groove can be more effectively improved, so that the vane pop-out property can be ensured more reliably.

  The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.

  The vane pump according to any one of claims 1 to 3, wherein the starting end side vane back pressure groove is provided so as to overlap the vane back pressure groove in a radial direction.

  According to the present invention, the start end side vane back pressure groove and the vane back pressure groove are provided so as to overlap in the radial direction, whereby the start end side vane back pressure groove and the vane back pressure groove can communicate with each other. Therefore, the discharge pressure introduced from the starting end side orifice can be introduced into the vane back pressure groove. As a result, the pressure of the vane back pressure groove is improved and the vane can be ejected more reliably.

It is a longitudinal cross-sectional view of the vane pump which concerns on this invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is the figure which showed only the 1st plate member of FIG. It is the figure which showed only the 2nd plate member of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pump body 2 ... Drive shaft 3 ... Rotor 3a ... Slot 4 ... 1st plate member 5 ... 2nd plate member 7 ... Vane 8 ... Cam ring 28 ... 1st suction port 29 ... Suction side vane back pressure groove 30 ... 1st Discharge port 31 ... Discharge side vane back pressure groove 32 ... Discharge small groove 33 ... Second suction port 34 ... Vane back pressure groove 35 ... Second discharge port 36 ... Start end side vane back pressure groove 37 ... Terminal end side vane back pressure groove 38 ... Start end side orifice passage 39 ... End portion side orifice passage

Claims (3)

A pump body;
A drive shaft pivotally supported on the pump body;
A rotor provided in the pump body and driven to rotate by the drive shaft;
A plurality of slots provided in the circumferential direction of the rotor, each of which is formed so as to extend radially outward from the bottom of the radially inner end ;
A vane provided respectively retractably in 該Su lot,
A cam ring that is formed in an annular shape and is swingably provided in the pump body, and forms a plurality of pump chambers together with the rotor and the vanes by abutting the vane on an inner peripheral surface;
A first plate member and a second plate member provided on both axial sides of the cam ring;
Provided on at least one side of said first plate member or the second plate member, a suction port that opens to the suction region the volume of the plurality of pump chambers is increased,
Before SL provided in the second plate member, and a discharge port opened to discharge the region volume of the plurality of pump chambers is reduced,
A pressure chamber provided in the pump body, into which hydraulic oil discharged from the discharge port is introduced;
A discharge passage that is provided in the pump body and discharges hydraulic oil introduced into the pressure chamber to the outside of the pump body;
A suction-side vane back pressure groove provided on the first plate member, formed to open to the bottom of the slot in the suction area of the rotor, and communicating the slot bottoms in the suction area ;
The first plate member is provided to be divided with the suction side vane back pressure groove, and is formed so as to open to the bottom of the slot over the entire discharge region of the rotor. A discharge-side vane back pressure groove communicating between the bottoms of the slots;
An introduction passage for supplying hydraulic oil discharged from the pump chamber in the discharge region to the discharge-side vane back pressure groove;
A terminal portion that is provided on the second plate and that is a rear end portion of the discharge region in the rotor rotation direction from a start end portion that is a front end portion of the discharge region in the rotor rotation direction toward the rotor rotation direction. Moreover, it is formed over a predetermined angle closer to the start end side and is formed so as to open to the slot bottom portion of the rotor, and the hydraulic oil in the discharge side vane back pressure groove causes the bottom portion of the slot to A leading end side vane back pressure groove introduced through
An opening formed in the start end side vane back pressure groove, and a start end side orifice passage for discharging hydraulic oil in the start end side vane back pressure groove to the pressure chamber ;
With
The starting end side orifice passage is formed so that the opening area becomes smaller as the vane is pushed into the slot at a position where the starting end side orifice passage and the slot of the rotor overlap. Vane pump. The second plate member is provided on the second plate member from the terminal end side of the discharge region in a direction opposite to the rotation direction of the rotor, and covers only a predetermined angle closer to the terminal end side than the starting end side vane back pressure groove. A terminal-side vane back pressure groove that is formed so as to open at the slot bottom of the rotor and into which hydraulic oil of the discharge-side vane back pressure groove is introduced through the slot bottom;
The opening part is formed in the said terminal part side vane back pressure groove, The terminal part side orifice channel | path which discharges the hydraulic fluid in the said terminal part side vane back pressure groove to the said pressure chamber is provided . Vane pump. 3. The vane pump according to claim 1, wherein the start end side vane back pressure groove is formed in an arc shape and is formed radially outside the vane back pressure groove in the discharge region .

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