JP5014841B2 - Variable displacement pump - Google Patents

Description

  The present invention relates to an improvement in a variable displacement pump that supplies lubricating oil to, for example, a sliding portion of an internal combustion engine.

  For example, as a conventional variable displacement pump applied to an internal combustion engine of a vehicle, one described in Patent Document 1 below is known.

  This variable displacement pump has a substantially bottomed cylindrical pump body having trochoidal inner teeth, a cover member that closes the opening of the pump body, and is eccentrically meshed with the inner peripheral side of the pump body. An adjustment ring that is rotatably arranged in the angular range, a pump element that is housed and arranged on the inner peripheral side of the adjustment ring, and that forms an internal gear by trochoidal teeth formed inside and outside, A drive shaft that is concentrically arranged with respect to the pump body and that rotationally drives the pump element by a drive force transmitted from the internal combustion engine is mainly constituted.

  The pump element includes: an outer rotor that is fitted to the inner peripheral surface of the adjustment ring; and an inner rotor that is fixed to the drive shaft so as to be integrally rotatable, and that is eccentrically inscribed (engaged) with the outer rotor. A plurality of pump chambers partitioned by corresponding internal and external teeth of the rotor are formed between the rotors. In addition, since the outer rotor is formed with a large number of teeth relative to the inner rotor, these rotors have a plurality of inner and outer teeth meshing, and there is no gap between the inner and outer teeth in one place. A meshing portion that meshes is formed, and a confinement portion in which the vertices of the inner and outer teeth are abutted is formed at a position facing the meshing portion (a position on the opposite side across the drive shaft).

  The inner bottom surface of the pump body is provided with a substantially crescent-shaped suction port and a discharge port that are symmetrically cut around the drive shaft, and the suction port is a closed portion from the meshing portion. The volume of each pump chamber gradually opens along the rotation direction from the closed portion to the meshing portion of the discharge port. The discharge side pump chamber opens on the side to be reduced. The suction port communicates with a suction hole that introduces hydraulic oil into the pump from the outside, while the discharge port communicates with a discharge hole that discharges hydraulic oil from the pump to the outside.

  The adjustment ring is engaged with a lever linked to an electric motor, and is rotated via the lever, thereby changing a relative meshing position of the adjustment ring with respect to the pump body. The discharge amount of the pump can be controlled by changing the mutual meshing position (phase) of the rotors.

That is, when the adjustment ring is positioned at one end in the rotational direction, the volumes of the pump chambers opened to the suction port and the discharge port are the same, and all the hydraulic oil sucked from the suction port is discharged. It is discharged to the port. On the other hand, when the adjustment ring is located on the other end side in the rotation direction, the volume of the discharge-side pump chamber that opens to the discharge port is reduced, and the amount of hydraulic oil discharged from the discharge-side pump chamber is reduced. At the same time, a part of the pump chamber on the suction side opens to the discharge port, and the surplus of the discharge oil discharged to the discharge port is returned to the suction side. As a result, energy loss of the apparatus based on excessive discharge is reduced.
JP-A-10-169571

  However, the conventional variable displacement pump has a structure in which surplus discharge oil is returned to the suction side via the suction side pump chamber when limiting the excess discharge amount of the pump. When the number of revolutions of the pump is high, the opening time of the suction side pump chamber with respect to the discharge port is short and the volume of the suction side pump chamber that opens to the discharge port is small. May not be in time, and all of the discharged excess oil may not be returned to the suction side.

  As a result, the amount of hydraulic oil that could not be returned is discharged as a result, and the surplus discharge amount of the pump cannot be sufficiently suppressed. Therefore, the surplus discharge amount is eventually reduced by other means such as a relief valve. As a result, problems such as a complicated pump structure and an increase in the number of parts have been caused.

  The present invention has been devised by paying attention to such a technical problem, and is a variable that can easily and sufficiently reduce the excess discharge amount of the pump without adding other parts such as a relief valve. A capacity pump is provided.

  The invention according to claim 1 is accommodated in the pump housing so as to be freely rotatable in a predetermined angle range, and has an adjustment ring having a lever portion on the outer peripheral portion, and is accommodated and disposed on the inner peripheral side of the adjustment ring. A pump element having a plurality of pump chambers separated from each other, the discharge amount changing according to the rotational position of the adjustment ring, and the pumps on the suction side of the working oil introduced into the pump housing A suction port that leads to the chamber, a discharge port that guides hydraulic oil discharged from each pump chamber on the discharge side of the pump element to the outside of the pump housing, and is accommodated in the pump housing, and is disposed in the adjustment ring. An urging means for applying an urging force to one side surface of the lever portion and holding the adjustment ring on one side in the rotational direction via the lever portion, and comprising the pump housing and the During the sailing, when the adjusting ring is rotated against the biasing force of the biasing means, is characterized in that a communicating path that communicates with the suction port and discharge port.

  According to the present invention, since the suction port and the discharge port are communicated with each other by the communication passage that opens to the discharge port as the lever portion rotates, the excess discharge of the pump regardless of the rotation speed of the pump. Oil can be reliably returned from the discharge port to the suction port, and the excess discharge amount of the pump can be suppressed to a minimum.

  In addition, in this case, the mechanism for returning the excess discharge amount of the pump to the suction side can be completed within the apparatus without using another mechanism such as a conventional relief valve, and the simple structure of simply adding the communication path. Since the above-described mechanism can be achieved by simple processing, there is no possibility of causing factors that lead to an increase in manufacturing cost, such as a complicated pump structure and an increased number of parts.

  The invention according to claim 2 is characterized in that the communication passage includes a housing side communication groove formed in a cutout in the inner surface of the pump housing.

  According to the present invention, since the communication path can be formed only by performing groove processing on at least the pump housing, a decrease in workability associated with the formation of the communication path is minimized.

  The invention according to claim 3 is characterized in that the communication passage is constituted by the housing side communication groove and a ring side communication groove formed in a cutout on an outer surface of the adjustment ring.

  According to the present invention, since the communication path is configured by both the housing side communication groove and the ring side communication groove, it is possible to improve the degree of design freedom when arranging the communication path. Therefore, the layout of the communication path can be optimized and an efficient communication path can be configured.

  Embodiments of a variable displacement pump according to the present invention will be described below in detail with reference to the drawings. In each embodiment, the variable displacement pump is applied to a vehicle engine oil pump.

  1 to 6 show a first embodiment of the present invention. As shown in FIGS. 1 and 3, this variable displacement pump has a pump housing chamber 4 having a substantially circular cross section that opens to one end in the axial direction. A pump body 1 that has an inner surface of the pump body 2 and a cover member 3 that closes the opening of the pump body 2 and is fastened by a plurality of bolts (not shown); An eccentric annular adjustment ring 5 that is fitted to the wall of the pump storage chamber 4 and is slidably rotated within a predetermined angular range; and a trochoid that is accommodated on the inner peripheral side of the adjustment ring 5. The pump element 6 is configured by an internal gear meshing with internal and external teeth, and is rotatably supported by the pump body 2 and the cover member 3. The pump element 6 is driven by the driving force transmitted from the engine. A drive shaft 7 that rotates, an urging means 8 that urges the adjustment ring 5 to one side in the rotational direction, and the adjustment ring 5 that is urged by the urging means 8 toward the one side. And restricting means 9 for restricting the rotation.

  As shown in FIG. 5, the pump body 2 is formed in a rectangular parallelepiped shape having a substantially rectangular cross section by an aluminum alloy or the like, and a bearing hole 2 a through which the drive shaft 7 is inserted is formed at a substantially central position. Has been. The pump housing chamber 4 formed concentrically with the bearing hole 2a is provided in the outer peripheral area on the opening side of the bearing hole 2a.

  Further, a notch is formed on the inner bottom surface of the pump body 2 around the bearing hole 2a on the lower half side in FIG. 5, and from the inner bottom surface of the pump housing chamber 4 toward the upper left in the same figure. Are also formed in the upper half side in FIG. 5 with a cutout formed in the upper half side in FIG. 5 and extended outward in the radial direction from the inner bottom surface of the pump housing chamber 4 toward the lower side in FIG. The discharged discharge port 12 is disposed to face the discharge port 12.

  The suction port 11 is connected to a suction hole 13 drilled upward from the lower side surface in FIG. 5, and the pump is accommodated from an oil pan through an oil passage pipe (not shown) connected to the suction hole 13. Hydraulic oil is introduced into the chamber 4. On the other hand, the discharge port 12 is connected to a discharge hole 14 drilled downward from the upper side surface in FIG. 5, and lubrication in the engine is performed via an oil passage pipe (not shown) connected to the discharge hole 14. Hydraulic oil is sent to the part.

  As shown in FIGS. 1 and 3, the pump element 6 is an internal gear formed by meshing inner and outer teeth of a trochoid shape or a cycloid shape as described above, and can rotate integrally with the outer peripheral surface of the drive shaft 7. An inner rotor 15 having four outer teeth 15a on the outer peripheral side, and five inner teeth 16a fitted on the inner peripheral surface of the adjustment ring 5 and meshing with the outer teeth 15a of the inner rotor 15. And an outer rotor 16 on the inner peripheral side.

  The outer rotor 16 is engaged with the inner rotor 15 in an eccentric state, and the rotors 15 and 16 are separated by corresponding inner and outer teeth 15a and 16a, respectively. , 16 are formed with a plurality of pump chambers 17 whose volumes change in accordance with the mutual meshing positions. Then, hydraulic oil is sucked into the pump chamber 17 from the front and rear sides in the axial direction through the suction port 11, and similarly, the hydraulic oil is discharged from the front and rear sides in the axial direction through the discharge port 12. ing.

  The adjustment ring 5 is formed so that the center C of the inner circumferential circle is eccentric by Δt with respect to the center O of the outer circumferential circle, thereby holding the outer rotor 16 eccentric with respect to the inner rotor 15. is doing. And the volume of each pump chamber 17 of the said pump element 6 is changed when this adjustment ring 5 rotates, and it becomes possible to change the discharge amount of this pump element 6 based on this. .

  Further, on the outer peripheral portion of the adjustment ring 5, there is a lever portion 10 that protrudes in a tangential direction and is urged by the urging means 8 to one side (counterclockwise direction in FIG. 1) of the rotation direction. As shown in FIG. 6, the cover member 3 is provided so as to be axially biased toward the sliding surface side. The lever portion 10 is a lever slide formed in a substantially arc shape from the outer end portion (left end portion in FIG. 1) of the discharge port 12 at the periphery of the pump housing chamber 4 on the joint surface of the pump body 2. The inner surface of the groove 20 is in sliding contact.

  The lever portion 10 is disposed adjacent to the discharge port 12, and has a substantially flat discharge pressure acting surface 10a on which the discharge pressure of the pump element 6 discharged into the discharge port 12 acts, and the discharge pressure acting surface. A substantially arc-shaped biasing force acting surface 10b which is formed in a substantially arc-shaped cross section on the back surface side of 10a and is in contact with the biasing means 8 to which the biasing force by the biasing means 8 acts. Yes.

  Further, a circumferential groove 21 which is a ring-side communication groove having a predetermined groove width and groove depth along the circumferential direction is cut out at the outer peripheral edge portion of the adjustment ring 5 on the surface facing the cover member 3. Accordingly, at the opening end surface of the pump body 2, one end (starting end) is opened in the circumferential groove 21 of the adjustment ring 5 and the other end (terminal end) is connected to the suction port 11. A connection groove 22 having a substantially U-shaped surface is cut out.

  The circumferential groove 21 has such a groove length that one end in the circumferential direction opens to the discharge port 12 and the other end opens to the suction port 11 when the adjustment ring 5 rotates by a predetermined amount. And it is formed in the circumferential direction position. That is, the circumferential groove 21 and the connecting groove 22 allow the discharge port 12 to communicate with the suction port 11 when the adjustment ring 5 is rotated by a predetermined amount.

  In addition, a plunger housing chamber 23 having a substantially rectangular cross section formed linearly along the vertical direction in FIG. 1 is provided on the end surface of the opening of the pump body 2 in the lever sliding groove 20. The urging means 8 is accommodated in the lever sliding groove 20 along the longitudinal direction.

  The urging means 8 is provided in the plunger accommodating chamber 23 so as to be slidable in the longitudinal direction, and has a substantially planar contact surface 24 a that contacts the urging force acting surface 10 b of the lever portion 10 of the adjustment ring 5. The plunger 24 is covered and is held between the back surface of the contact surface 24a of the plunger 24 and the lower end surface of the plunger housing chamber 23 in FIG. 1, and the plunger 24 is attached upward in FIG. And a coil spring 25 for energizing.

  The urging means 8 urges the lever portion 10 of the adjustment ring 5 to one side in the rotational direction by the spring force of the coil spring 25 having a predetermined spring constant, thereby causing the adjustment ring 5 to move to the one side. The rotating end position on the side is held. At this time, the contact surface 24a of the plunger 24 that contacts the biasing force acting surface 10b formed in a substantially circular arc shape in the lever portion 10 is formed into a flat surface, and the mutual contact is set as a point contact. The spring 25 is expanded and contracted as linearly as possible to suppress the bending of the coil spring 25 to a minimum.

  The restricting means 9 includes a protrusion 26 formed on the outer peripheral portion of the adjustment ring 5 with the same width as the lever portion 10, an outer edge of the discharge port 12, and an outer peripheral edge of the pump housing chamber 4. The regulating wall 27 is provided at the boundary, and the protrusion 26 is brought into contact with the regulating wall 27 to regulate the rotational end position on the one side of the adjustment ring 5.

  Further, between the plunger housing chamber 23 and the lever sliding groove 20, one end (starting end) is connected to the lever sliding groove 20 and the other end (terminal end) is connected to the suction port 11. A first communication groove 28 that is a substantially L-shaped housing side communication groove is formed in a cutout.

  The first communication groove 28 is set to a depth deeper than the lever sliding groove 20 and the plunger housing chamber 23, and the groove portion along the vertical direction in FIG. It is erected in the chamber 23. The starting end position of the first communication groove 28 does not open to the discharge port 12 when the adjustment ring 5 is held at the one rotation end position, and the lever of the adjustment ring 5 is not opened. The position is set at such a position that the portion 10 is communicated to the discharge port 12 side only when the portion 10 is pressed by the discharge oil of the pump and pushed down to a predetermined rotational position on the other side. That is, the lever sliding groove 20 and the first communication groove 28 allow the discharge port 12 to communicate with the suction port 11 when the adjustment ring 5 is rotated by a predetermined amount or more.

  Further, a second communication groove 29 is formed on the surface of the cover member 3 facing the pump body 2, at a position facing the first communication groove 28, so as to be cut out in substantially the same shape as the first communication groove 28. Is provided. Similarly to the first communication groove 28, the second communication groove 29 also communicates with the discharge port 12 only at one end (starting end) when the lever portion 10 of the adjustment ring 5 is pushed down to a predetermined rotation position. The other end (terminal) is connected to the suction port 11. That is, the discharge port 12 communicates with the suction port 11 through the second communication groove 29 and the lever sliding groove 20 when the adjustment ring 5 is rotated by a predetermined amount or more by the second communication groove 29. It is supposed to be.

  With the configuration as described above, the variable displacement pump has such a coil when the discharge pressure of the pump element 6 is smaller than a predetermined set pressure, that is, a spring force of the coil spring 25 set to a predetermined value. The adjustment ring 5 is held at the rotational end position on the one side by the spring force of the spring 25. As a result, the meshing position of the pump element 6 is maintained so that the volumes of the pump chambers 17a and 17b that open to the suction port 11 and the discharge port 12 are equal to each other, and according to the discharge amount of the pump element 6 A hydraulic oil amount is discharged from the discharge hole 14. Hereinafter, the meshing position of the pump element 6 will be referred to as a maximum discharge position.

  On the other hand, when the discharge pressure of the pump element 6 exceeds the set pressure, the lever portion 10 resists the spring force of the coil spring 25 by the discharge pressure of the pump element 6 acting on the discharge pressure acting surface 10a. As a result, the adjustment ring 5 is turned to the other side in the turning direction. As a result, the meshing position of the pump element 6 is changed in a direction in which the volume of the pump chamber 17b opening to the discharge port 12 is reduced, and as a result, the discharge amount of the pump element 6 is suppressed. Hereinafter, the meshing position of the pump element 6 will be referred to as a discharge restriction position.

  Further, by changing the meshing position of the pump element 6 to the discharge restriction position, the volume of the discharge-side pump chamber 17b is reduced as described above, and the discharge amount itself is reduced. A part of the suction side pump chamber 17a is opened to the discharge port 12 where the positive pressure is reached, and the excess discharged into the discharge port 12 is taken into the suction side pump chamber 17a and returned to the suction side again. It is. Thereby, it is possible to further reduce the excess discharge of the pump.

  Subsequently, a characteristic operation of the variable displacement pump according to the present embodiment will be described with reference to FIGS.

  First, when the discharge pressure of the pump element 6 is lower than the set pressure, the adjustment ring 5 is held at the rotational end position on the one side as described above. As described above, the circumferential end of the circumferential groove 21 is kept closed. Therefore, since the hydraulic oil in the discharge port 12 does not flow into the connection groove 22, the hydraulic oil in the discharge port 12 is not recirculated to the suction port 11.

  In a state where the adjustment ring 5 is held at the rotation end position on the one side, the lever portion 10 of the adjustment ring 5 is located on the lever sliding groove 20, and the first and second Since the communication grooves 28 and 29 and the discharge port 12 are separated from each other by the lever portion 10, the first and second communication grooves 28 and 29 are respectively connected to the discharge port 12. It is out of communication. Accordingly, also in this case, the hydraulic oil in the discharge port 12 does not flow into any communication groove of the first and second communication grooves 28 and 29, and the first and second communication grooves 28 and 29. Even if it passes through, it does not recirculate to the suction side.

  Thus, when the discharge pressure of the pump element 6 is lower than the set pressure, any of the circumferential groove 21 and the first and second communication grooves 28 and 29 can cause the discharge in the discharge port 12. Since the hydraulic oil is not recirculated to the suction port 11, the discharge amount of the pump is not limited at all, and the discharge amount of the pump element 6 is directly discharged through the discharge hole 14. .

  On the other hand, when the discharge pressure of the pump element 6 exceeds the set pressure, the adjustment ring 5 rotates to the other side against the spring force of the coil spring 25 as described above. Begin to. As shown in FIGS. 3 and 4, when the adjustment ring 5 rotates more than a set amount, one end in the circumferential direction of the circumferential groove 21 opens to the discharge port 12. The discharge port 12 and the suction port 11 of the pump body 2 are in communication with each other through the circumferential groove 21 and the connection groove 22. As a result, as shown by the arrow in FIG. 3, the high-pressure discharged oil flows into the circumferential groove 21 and is returned to the suction port 11 having a low pressure through the connection groove 22.

  At the same time, when the lever portion 10 is pushed down more than the set amount, the start end of the first communication groove 28 communicates with the discharge port 12 side, and accordingly, the first communication groove The discharge port 12 and the suction port 11 of the pump body 2 are in communication with each other via the lever 28 and the lever sliding groove 20. As a result, surplus discharge oil in the discharge port 12 flows into the first communication groove 28 via the lever sliding groove 20 as shown by arrows in FIGS. The gas is returned to the suction port 11 through a gap formed between the plunger 24 and the plunger 24.

  Similarly, the starting end of the second communication groove 29 is also communicated with the discharge port 12, whereby the discharge port 12 and the suction port 11 communicate with each other via the second communication groove 29 and the lever sliding groove 20. It becomes a state. As a result, surplus discharge oil in the discharge port 12 is recirculated to the suction port 11 through the second communication groove 29 as indicated by an arrow in FIG.

  The hydraulic fluid recirculated to the suction port 11 is introduced into the pump chamber 17a on the suction side of the pump element 6, pressurized by the pump chambers 17, and then discharged again to the discharge port 12. It has come to be.

  As described above, in the variable capacity pump, when the discharge pressure of the pump element 6 exceeds the set pressure, the circumferential groove 21 and the connection groove 22, and the first and second communication grooves. 28, 29 is used to recirculate excess discharge oil in the discharge port 12 to the suction side, that is, the discharge port 12 and the suction port 11 are formed by the grooves 21, 22, 28, 29 serving as so-called bypass passages. Since each of them is configured to physically communicate with each other, it is possible to reliably return the excessively discharged excess discharged oil to the suction side without being affected at all by the rotational speed of the pump. As a result, it is possible to eliminate (eliminate) a so-called relief valve that has been conventionally required to return the surplus discharge oil of the pump to the suction side, and the structure of the pump can be simplified.

  In addition, by adopting a structure in which the hydraulic oil in the discharge port 12 is recirculated through the circumferential grooves 21 and the connection grooves 22 and the plurality of grooves of the first and second communication grooves 28 and 29, these are adopted. It is possible to secure a sufficient flow path area for the hydraulic oil to flow through the grooves, and freely adjust the flow rate of the hydraulic oil by changing the flow path area (cross-sectional area) of these grooves. Therefore, it is possible to return almost all of the excess discharged oil to the suction side without being affected by the amount of excess discharged oil.

  Furthermore, since the opening amount of the circumferential groove 21 and the first and second communication grooves 28 and 29 with respect to the discharge port 12 is changed according to the rotation amount of the lever portion 10, it becomes redundant. An appropriate amount of discharged oil corresponding to the amount of discharged oil can be returned to the suction side.

  Since the circumferential groove 21 and the connection groove 22 and the first and second communication grooves 28 and 29 are all simple grooves configured in a simple shape, along with the formation of these grooves. Deterioration of the productivity of the pump can be prevented, and an increase in manufacturing cost can be suppressed.

  Therefore, according to this embodiment, the discharge port 12 is formed by the circumferential groove 21 and the first and second communication grooves 28 and 29 that open to the discharge port 12 as the lever portion 10 rotates. And the suction port 11 to which these grooves are connected are directly connected to each other so that excess discharge oil can be reliably transferred from the discharge port 12 to the suction port 11 without being affected at all by the rotational speed of the pump. It becomes possible to return to this, and the excessive discharge amount of this pump can be suppressed to the minimum. Thereby, the energy loss of the pump resulting from this excessive discharge can be suppressed, and it can contribute to the improvement of fuel consumption.

  The surplus discharge oil recirculation structure having such a configuration can be completed within the apparatus without using another mechanism such as a relief valve as in the prior art, and the circumferential groove 21 and the first and second grooves can be completed. Since it can be achieved by simple processing only by adding the communication grooves 28 and 29, there is no possibility of causing factors that lead to an increase in manufacturing cost, such as a complicated pump structure and an increased number of parts.

  Furthermore, by configuring the communication path that connects the suction port 11 and the discharge port 12 by both grooves of the circumferential groove 21 that is a communication groove on the ring side and the connection groove 22 that is a communication groove on the housing side, Since it becomes possible to improve the design freedom at the time of arrange | positioning this communicating path, the layout of this communicating path can be optimized and an efficient communicating path can be comprised.

  Further, since the mutual contact between the biasing force acting surface 10b of the lever portion 10 and the contact surface 24a of the plunger 24 is a point contact, the deflection of the coil spring 25 is suppressed to the minimum. The life of the coil spring 25 can be extended, and the stability of the spring force of the coil spring 25 can be improved.

  7 to 10 show a second embodiment of the variable displacement pump according to the present invention. The basic configuration is the same as that of the first embodiment, and the configuration of the adjustment ring 5 is mainly changed. It is a thing. In the following, for convenience, the same components (members) as those in the first embodiment will be described with the same reference numerals, description of overlapping parts will be omitted, and only different parts will be described.

  That is, as shown in FIGS. 7 and 8, the variable displacement pump in this embodiment has a trochoidal or cycloid profile on the outer peripheral portion of the adjusting ring 5 that holds the pump element 6 on the inner peripheral side. While the external teeth 5a are formed, the peripheral wall of the pump housing chamber 4 of the pump body 2 has one more tooth than the external teeth 5a ... meshed with the external teeth 5a ... of the adjusting ring 5. Internal teeth 4a ... are formed.

  As a result, the adjusting ring 5 is meshed and accommodated in the pump accommodating chamber 4 in an eccentric state by Δt with respect to the bearing hole 2 a of the pump body 2, and the outer rotor 16 with respect to the inner rotor 15. Is held in an eccentric state, and the mutual meshing position (phase) of the rotors 15 and 16 is changed by rotating.

  Further, at a predetermined position on the outer peripheral portion of the adjustment ring 5, a lever portion 10 that protrudes larger than the external teeth 5 a and 5 b between the adjacent external teeth 5 a and 5 b is provided in the pump body 2. The adjustment ring 5 protrudes outward in the radial direction so as to face the plunger accommodation chamber 23 provided in the accommodation chamber 4.

  The lever portion 10 is formed so that both sides of the adjustment ring 5 in the rotation direction are substantially flat, and the plunger 24 is formed in a substantially hemispherical shape on the biasing force acting surface 10b which is one side surface. The contact surface 24a is always elastically contacted by point contact, and the discharge pressure of the pump element 6 guided through a communication groove 31 described later acts on the discharge pressure acting surface 10a which is the other side. .

  When the discharge pressure of the pump element 6 acting on the discharge pressure acting surface 10 a of the lever portion 10 is smaller than the spring force of the coil spring 25, the discharge pressure acting surface 10 a is formed in the plunger housing chamber 23. By abutting against the restriction wall 27 provided on the upper wall portion, the rotation of the adjustment ring 5 to one side (counterclockwise in FIGS. 7 and 8) is restricted. It is the state hold | maintained at the rotation end position of the side.

  At this time, the external teeth 5 a adjacent to the discharge pressure acting surface 10 a side of the lever portion 10 are abutted against the internal teeth 4 a located between the discharge port 12 and the plunger accommodating chamber 23 in the pump body 2 and sealed. In this state, the hydraulic oil in the discharge port 12 does not flow into the plunger accommodating chamber 23. The inner and outer teeth 4a and 5a are always in contact with each other in the rotation range of the adjustment ring 5 so that the discharge port 12 and the plunger housing chamber 23 are separated from each other.

  In addition, a substantially linear communication groove 31 is formed on the opening end surface of the pump body 2 along the substantially vertical direction in FIGS. 7 and 8 at the boundary between the pump housing chamber 4 and the plunger housing chamber 23. A cutout is formed, and the hydraulic oil in the discharge port 12 can be guided into the plunger accommodating chamber 23 through the communication groove 31.

  The communication groove 31 is provided such that one end (starting end) opens into the pump housing chamber 4 and the other end (terminal end) opens into the plunger housing chamber 23. The starting end of the communication groove 31 is in a pressure chamber 30 defined by the inner and outer teeth 4a and 5a and the lever portion 10 in a state where the adjustment ring 5 is held at the rotation end position on the one side. The position is set such that the adjustment ring 5 does not open and communicate with the discharge port 12 of the pump body 2 but communicates with the discharge port 12 only when the adjustment ring 5 rotates by a predetermined amount toward the other side.

  Further, a connection groove 32 for connecting the suction port 11 of the pump body 2 and the plunger accommodating chamber 23 is formed in the opening end surface of the pump body 2 by a notch. As a result, the hydraulic oil introduced into the plunger housing chamber 23 from the discharge port 12 through the communication groove 31 is guided to the suction port 11.

  Also for the variable displacement pump according to the present embodiment having the above-described configuration, the basic operation as a pump is as described in detail in the first embodiment. Only characteristic actions will be described with reference to FIGS.

  First, when the discharge pressure of the pump element 6 is lower than the set pressure, as shown in FIG. 7, the adjustment ring 5 is held at the rotational end position on the one side, and the communication groove 31 The starting end is maintained in a state where communication with the discharge port 12 is blocked by the sealing action of the inner and outer teeth 4a and 5a while being open to the pressure chamber 30 as described above. Therefore, the hydraulic oil in the discharge port 12 does not flow into the communication groove 31, and the hydraulic oil in the discharge port 12 is not recirculated to the suction port 11. The discharge amount is not limited at all, and the discharge amount of the pump element 6 is discharged through the discharge hole 14 as it is.

  On the other hand, when the discharge pressure of the pump element 6 exceeds the set pressure, the external teeth 5a of the adjusting ring 5 facing the discharge port 12 of the pump body 2 are rotated in the other direction of rotation. The adjustment ring 5 is pushed down to the side, and starts to rotate to the other side against the spring force of the coil spring 25. When the adjustment ring 5 rotates more than the set amount, as shown in FIG. 8, the start end of the communication groove 31 communicates with the discharge port 12, and as indicated by an arrow in the figure. In addition, excess discharge oil in the discharge port 12 flows into the plunger accommodating chamber 23 through the communication groove 31. Thus, the surplus discharged oil that has flowed into the plunger accommodating chamber 23 is finally returned to the suction port 11 via the connection groove 32.

  Therefore, in this embodiment as well, it is possible to obtain the same effect as that of the first embodiment, and in the variable displacement pump according to the present embodiment, the pump body 2 Since the suction port 11 and the discharge port 12 can communicate with each other only by forming the groove, that is, only by forming the communication groove 31 and the connection groove 32 in the pump body 2, the workability is reduced due to the formation of the communication path. Can be minimized.

  In the variable displacement pump according to the present embodiment, the engagement of the pump element 6 is achieved by adopting a structure in which the adjustment ring 5 is engaged with the pump body 2 by internal and external teeth having a trochoidal or cycloidal profile. Since the amount of rotation of the adjustment ring 5 when changing the position (phase) can be reduced, the responsiveness of the pump can be improved.

  Further, in the case of the variable displacement pump, the amount of rotation of the adjustment ring 5 accompanying the phase change of the pump element 6 can be reduced, so that the discharge port 12 can be disposed within the limited rotation range of the adjustment ring 5. It is possible to change the meshing phase so that the volume of the pump chamber 17b that opens is substantially zero. Thereby, the discharge amount of the pump element 6 itself can be suppressed as much as possible, and the excessive discharge of the pump can be more reliably suppressed.

  FIGS. 11 to 13 show a third embodiment of the variable displacement pump according to the present invention, in which the return path in the second embodiment is changed.

  That is, in the variable capacity pump in this embodiment, as shown in FIGS. 11 to 13, the length of the communication groove 31 is slightly shorter than that of the second embodiment. Specifically, the groove length is set such that the start end of the communication groove 31 does not communicate with the discharge port 12 even when the adjustment ring 5 is rotated to the maximum position of the other side.

  Instead, in the vicinity of the upper wall portion of the plunger housing chamber 23, a substantially arc-shaped cutout groove 33 that always opens to the pressure chamber 30 when the adjustment ring 5 rotates is provided on the plunger housing chamber 23. A notch is formed so as to extend to the inner teeth 4 a provided in the vicinity of the wall, and is provided biased toward the opening side of the pump body 2. In addition, by forming the notch groove 33 so as to be biased toward the opening side of the pump body 2 in this way, the regulation wall 27 remains on the bottom side.

  The cutout groove 33 does not communicate with the discharge port 12 when the adjustment ring 5 is held at the rotation end position on the one side, and the discharge is not performed until the adjustment ring 5 rotates by a predetermined amount. The groove depth is set so as to communicate with the port 12. That is, when the adjustment ring 5 is rotated by a predetermined amount, surplus discharge oil in the discharge port 12 is introduced into the pressure chamber 30 by the notch groove 33, and the communication groove 31 is introduced through the pressure chamber 30. It is comprised so that the said excess discharge oil may flow in.

  When the discharge pressure of the pump element 6 is lower than the set pressure, the variable displacement pump according to the present embodiment configured as described above has the adjustment ring 5 as the one side as shown in FIG. The rotation end position on the side is held, and the connection of the notch groove 33 to the discharge port 12 is maintained by the sealing action of the inner and outer teeth 4a and 5a as described above. Therefore, the hydraulic oil in the discharge port 12 does not flow into the notch groove 33, so that the hydraulic oil in the discharge port 12 is not recirculated to the suction port 11. The discharge amount is not limited at all, and the discharge amount of the pump element 6 is discharged through the discharge hole 14 as it is.

  On the other hand, when the discharge pressure of the pump element 6 exceeds the set pressure, the external teeth 5a of the adjustment ring 5 are pressed by the discharge pressure. Rotate to the other side against the spring force of 25. When the adjustment ring 5 rotates more than a set amount, the cutout groove 33 communicates with the discharge port 12 as shown in FIG. 12, and the discharge port is connected via the cutout groove 33. The surplus discharge oil in 12 flows into the communication groove 31. Thus, the surplus discharged oil that has flowed into the communication groove 31 is finally returned to the suction port 11 through the plunger housing chamber 23 and the connection groove 22 as indicated by the arrows in FIG. .

  Therefore, even in the variable displacement pump according to this embodiment, the same operation as that of the variable displacement pump according to the second embodiment can be obtained.

  In the present embodiment, the communication groove 31 is not directly connected to the discharge port 12. However, the communication groove 31 and the cutout groove 33 can be formed by directly connecting the communication groove 31 to the discharge port 12. It is also possible to return the excess discharge oil in the discharge port 12 to the suction side by the two grooves. In this case, more excess discharge oil can be transported to the suction side, so that a more efficient recirculation action can be obtained.

  FIGS. 14-16 shows 4th Embodiment of the variable displacement pump which concerns on this invention, It applies to the sliding surface with the said pump storage chamber 4 of the said adjustment ring 5 in the said 3rd Embodiment. A second notch groove that is a ring-side communication groove that communicates with the communication groove 31 and introduces excess discharge oil in the discharge port 12 of the pump body 2 into the communication groove 31 when the adjustment ring 5 rotates by a predetermined amount. 34 is added.

  The second notch groove 34 is adjusted from the tooth surface on the discharge port 12 side of the external tooth 5a of the adjustment ring 5 that seals between the discharge port 12 and the pressure chamber 30 toward the lever portion 10 side. A notch is formed in a substantially straight line in the tangential direction of the ring 5.

  In the variable displacement pump according to the present embodiment configured as described above, when the discharge pressure of the pump element 6 is lower than the set pressure, as shown in FIG. Since it is in a non-communication state with respect to the communication groove 31 and the notch groove 33 is also disconnected from the discharge port 12 by the sealing action of the inner and outer teeth 4a and 5a, the inside of the discharge port 12 The hydraulic oil does not flow into the communication groove 31, so that the hydraulic oil in the discharge port 12 is not recirculated to the suction port 11. For this reason, the discharge amount of the pump is not limited at all, and the discharge amount of the pump element 6 is directly discharged through the discharge hole 14.

  On the other hand, when the discharge pressure of the pump element 6 exceeds the set pressure, the external teeth 5a of the adjustment ring 5 are pressed by the discharge pressure and rotated to the other side, and this adjustment is performed. When the ring 5 rotates more than a set amount, as shown in FIG. 15, the cutout groove 33 communicates with the discharge port 12, so that excess discharge oil in the discharge port 12 passes through the cutout groove 33. At the same time as flowing into the communication groove 31, the second cutout groove 34 communicates with the communication groove 31, so that surplus discharge oil in the discharge port 12 is passed through the second cutout groove 34. Flow into. Thus, the excess discharged oil that has flowed into the communication groove 31 via both the notch groove 33 and the second notch groove 34 is finally supplied to the pump body 2 via the plunger housing chamber 23 and the connection groove 22. Is returned to the suction port 11.

  Therefore, according to this embodiment, the same action as that of the third embodiment can be obtained, and the addition of the second notch groove 34 allows a larger amount of the excess discharged oil to be discharged. Since it becomes possible to carry to the suction side, a more efficient recirculation action can be obtained.

The technical ideas other than the invention described in each of the claims ascertained from the respective embodiments will be described below.
(1) Pump discharge pressure is applied to the other side of the lever portion of the adjustment ring, and the rotation position of the adjustment ring is changed according to the difference between the pump discharge pressure and the urging force of the urging means. The variable displacement pump according to claim 1.
(2) The predetermined oil amount of the pump discharge amount is returned from the discharge port to the suction port as the suction port and the discharge port communicate with each other through the communication path. The variable displacement pump described.
(3) When the suction port and the discharge port communicate with each other through the communication path, a predetermined amount of oil corresponding to the rotational position of the adjustment ring is returned from the discharge port to the suction port. The variable displacement pump according to claim 1.
(4) The variable capacity pump according to claim 1, wherein the lever portion is formed to protrude radially outward from an outer peripheral portion of the adjustment ring.
(5) The variable capacity pump according to claim 1, wherein the lever portion is formed by cutting out an outer peripheral portion of the adjustment ring along a rotation direction.
(6) The biasing force acting surface on which the biasing force acts in the lever portion is formed in a substantially arc shape, while the contact surface of the biasing means that contacts the biasing force acting surface is formed in a substantially planar shape. The variable displacement pump according to claim 1, wherein

According to this invention, it is possible to make the mutual contact between the biasing force acting surface of the lever portion and the contact surface of the biasing means a point contact, and to minimize the deflection of the biasing means. it can. Thereby, the life of the urging means can be extended and the stability of the urging force of the urging means can be improved.
(7) The biasing force acting surface on which the biasing force acts in the lever portion is formed in a substantially flat shape, while the contact surface of the biasing means that contacts the biasing force action is formed in a substantially arc shape. The variable displacement pump according to claim 1.

According to this invention, it is possible to make the mutual contact between the biasing force acting surface of the lever portion and the contact surface of the biasing means a point contact, and to minimize the deflection of the biasing means. it can. Thereby, the life of the urging means can be extended and the stability of the urging force of the urging means can be improved.
(8) The variable displacement pump according to claim 1, wherein the adjustment ring rotates within a range in which the suction port and the discharge port can communicate with each other via the communication path.
(9) The variable capacity pump according to (8), characterized in that a regulating means for regulating the rotation of the adjusting ring is provided between the adjusting ring and the pump housing.
(10) In the above (9), the restricting means may be constituted by a protruding portion protruding from an outer peripheral portion of the adjusting ring and a restricting wall provided inside the pump housing. Variable displacement pump.
(11) The variable displacement pump according to (9), wherein the restricting means is configured by a lever portion of the adjustment ring and a restricting wall provided inside the pump housing.

  The present invention is not limited to the configuration of each of the embodiments described above, and in particular, the size and shape of the grooves 21, 22, 28, 29, 31 to 34 and the ports 11 and 12, and the adjustment ring 5 The number of teeth of the pump element 6 and the like can be freely changed according to the specifications of the pump, and the configurations of the pump body 2 and the cover member 3 can be set oppositely.

  Further, in each of the above embodiments, the lever portion 10 is provided in a protruding shape. However, the lever portion 10 is provided with a notch portion at a predetermined position on the outer peripheral surface of the adjustment ring 5 and the adjustment ring. It is also possible to constitute by forming a part of the outer peripheral surface of 5 in a stepped shape. In other words, the function of the lever portion 10 is sufficiently fulfilled by providing a stepped portion on the outer peripheral surface of the adjusting ring 5 to the extent that the plunger 24 is hooked. Which shape is used can be arbitrarily set.

  In the second to fourth embodiments, the communication groove 31 is provided in the pump body 2, but the same is true even when the communication groove 31 is provided in the cover member 3. As a matter of course, the operation and effect can be obtained, and by providing the communication groove 31 in both the pump body 2 and the cover member 3 as in the first embodiment, both surfaces of the pump body 2 and the cover member 3 are provided. It is also possible to return the excess discharge oil from the pump to the suction port 11. In this case, more hydraulic oil can be conveyed to the suction port 11 side, so that the excess discharge oil of the pump can be recirculated more efficiently.

FIG. 9 shows the pump state when the adjustment ring is held at one of the rotational end positions in the first embodiment of the variable displacement pump according to the present invention, and the variable displacement pump is joined to the pump body. It is the front view seen from the surface. It is the sectional view on the AA line of FIG. The variable displacement pump according to the first embodiment of the present invention shows the state of the pump when the adjustment ring is fully rotated to the other side, and the variable displacement pump is viewed from the joint surface of the pump body. It is a front view. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a front view of the pump body simple substance which shows the embodiment. It is a perspective view of the adjustment ring which shows the embodiment. In the second embodiment of the variable displacement pump according to the present invention, the state of the pump when the adjustment ring is held at the rotational end position on one side is shown, and the variable displacement pump is joined to the pump body. It is the front view seen from the surface. In the second embodiment of the variable displacement pump according to the present invention, the state of the pump when the adjustment ring is rotated to the other side is shown, and the variable displacement pump is viewed from the joint surface of the pump body. It is a front view. It is a perspective view of the pump body simple substance which shows the embodiment. It is a perspective view of the adjustment ring which shows the embodiment. In the third embodiment of the variable displacement pump according to the present invention, the state of the pump in the case where the adjustment ring is held at the rotational end position on one side is shown, and the variable displacement pump is joined to the pump body. It is the front view seen from the surface. In the third embodiment of the variable displacement pump according to the present invention, it shows the state of the pump when the adjustment ring is fully rotated to the other side, and the front of the variable displacement pump viewed from the joint surface of the pump body. FIG. It is a perspective view of the pump body simple substance which shows the embodiment. In the fourth embodiment of the variable displacement pump according to the present invention, the state of the pump when the adjustment ring is held at the rotational end position on one side is shown, and the variable displacement pump is joined to the pump body. It is the front view seen from the surface. In the fourth embodiment of the variable displacement pump according to the present invention, it shows the state of the pump when the adjustment ring is fully rotated to the other side, and the front of the variable displacement pump viewed from the joint surface of the pump body. FIG. It is a perspective view of the adjustment ring which shows the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pump housing 5 ... Adjustment ring 6 ... Pump element 7 ... Drive shaft 8 ... Energizing means 9 ... Restricting means 10 ... Lever part 20 ... Lever sliding groove (communication path)
21 ... Circumferential groove (communication path)
22 ... Connection groove (communication path)
28 ... 1st communication groove (communication path)
29 ... Second communication groove (communication path)

Claims (3)

An adjustment ring that is rotatably accommodated within a predetermined angular range in the pump housing and has a lever portion on the outer periphery;
A pump element that is housed and arranged on the inner peripheral side of the adjustment ring and has a plurality of pump chambers that are separated from each other; and a discharge amount that varies depending on a rotation position of the adjustment ring;
A suction port for guiding the hydraulic oil introduced into the pump housing to the pump chambers on the suction side;
A discharge port for guiding hydraulic oil discharged from each pump chamber on the discharge side of the pump element to the outside of the pump housing;
An urging means that is accommodated in the pump housing, applies an urging force to one side surface of the lever portion of the adjustment ring, and holds the adjustment ring on one side in the rotational direction via the lever portion; With
A communication path is provided between the pump housing and the adjustment ring for communicating the suction port and the discharge port when the adjustment ring rotates against the biasing force of the biasing means. Variable displacement pump. The variable displacement pump according to claim 1, wherein the communication passage includes a housing side communication groove formed in a cutout in an inner surface of the pump housing. The variable displacement pump according to claim 2, wherein the communication path is configured by the housing side communication groove and a ring side communication groove formed in a notch on an outer surface of the adjustment ring.

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