JP2015140744A - Fluid pump flow rate control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a pump flow rate from an oil pump to be classified more preferably in response to a required flow rate used in an entire hydraulic pressure control system.SOLUTION: An oil passage changing-over valve 2 selectively communicates the first in-flow port 7a and the second in-flow port 7b with a supply port 7e through operation of a spool 8 or enables both in-flow ports 7a, 7b to be communicated with the supply port, and a control unit 21 selects one discharging mode from a small discharging mode for communicating the first in-flow port 7a with the supply port 7e, a middle discharging mode for communicating the second in-flow port 7b with the supply port 7e and a full-discharging mode for communicating both in-flow ports 7a, 7b with the supply port 7e in response to a fluid flow rate required by a control mechanism. As a result, a pump flow rate from an oil pump 1 can be classified more preferably in response to a required flow rate used in the entire hydraulic pressure control system.

Description

  The present invention relates to a flow rate control device for a fluid pump that can switch the discharge flow rate of the fluid pump in three stages.

  Conventionally, fluid pumps such as balanced vane pumps and continuous contact internal gear pumps that are driven by a drive system such as an engine are driven by the rotational speed of the drive system because the rotational speed fluctuates in conjunction with the rotational speed of the drive system. When the system is rotated at a high speed, the rotational speed of the fluid pump is also increased, and an unnecessarily high flow rate is discharged, resulting in a problem that fuel efficiency deteriorates due to power loss.

  Therefore, for example, in Patent Document 1 (Japanese Patent No. 3391355), the discharge port of the fluid pump is divided into a main port and a subport, and the required flow rate used in the entire continuously variable transmission hydraulic control system is determined from the main port. If it is within the value obtained by adding the hysteresis flow rate to the pump flow rate, the oil discharged from the sub-port is circulated to the suction side and only the main port is loaded, and the required flow rate exceeds the pump flow rate. In such a case, a technology is disclosed in which the sub port is opened to perform load operation by both the main port and the sub port.

  According to the technique disclosed in this document, when the required flow rate is within the pump flow rate from the main port, the oil from the sub pump is circulated as it is, so that wasteful power consumption of the fluid pump is reduced and fuel efficiency is improved. Can be realized.

Japanese Patent No. 3391355

  However, in the technique disclosed in the above-mentioned document, the flow rate of the fluid pump can be switched only in two stages. For example, even when the required flow rate is significantly lower than the pump flow rate from the main port, Fluid continues to be supplied only from the main port. Similarly, when the required flow rate slightly exceeds the pump flow rate from the main port, load operation by both the main port and the sub port is started.

  As a result, a sufficient control region for the pump flow rate cannot be ensured, and power loss occurs, so there is a limit to realizing higher fuel efficiency improvement.

  In view of the above circumstances, the present invention can more optimally classify the pump flow rate from the fluid pump according to the required flow rate used in the entire hydraulic control system, and ensure a sufficient control area in the entire fluid pump. An object of the present invention is to provide a flow control device for a fluid pump that can further reduce wasteful power loss and achieve higher fuel efficiency.

  In the present invention, a suction-side oil reservoir chamber, a discharge-side first oil reservoir chamber, and a discharge-side second oil reservoir chamber are formed in a pump casing, and the fluid sucked from the suction-side oil reservoir chamber according to the operation of the drive system. Driven by the drive system, a fluid pump that discharges to each of the oil reservoirs, a first inflow port that communicates with the discharge-side first oil reservoir, a second inflow port that communicates with the discharge-side second oil reservoir. An oil passage switching valve having a supply port communicated to the control mechanism side, a valve body for switching the flow rate of fluid supplied to the control mechanism by communicating each inflow port and the supply port; And a control unit for controlling the flow rate of the fluid supplied to the control mechanism by controlling the switching of the path switching valve. The inflow port and the second inflow port are connected to the supply port. A first discharge mode for communicating the first inflow port with the supply port, and the second inflow port. According to the fluid flow rate required by the control mechanism, one discharge mode is selected from the second discharge mode in which the port communicates with the supply port, and all the discharge modes in which the both inflow ports communicate with the supply port. select.

  According to the present invention, the oil path switching valve can selectively communicate the first inflow port and the second inflow port with the supply port by the operation of the valve body, or both the inflow ports can communicate with the supply port. The control unit communicates the first inflow port and the supply port with each other, the first discharge mode with which the second inflow port communicates with the supply port, and the all discharge mode with which both inflow ports and the supply port communicate with each other. Since one discharge mode is selected according to the fluid flow rate required by the control mechanism, the pump flow rate from the fluid pump is more optimal according to the required flow rate used in the entire hydraulic control system It becomes possible to classify, and it is possible to secure a sufficient control region in the entire fluid pump and reduce unnecessary power loss, thereby realizing higher fuel efficiency improvement.

Functional block diagram of the flow control device according to the first embodiment Same as above, flowchart showing a switching determination processing routine (A) is explanatory drawing of the discharge mode divided by a small flow volume threshold curve and a large flow volume threshold curve, (b) is explanatory drawing which shows the relationship between the control pressure which operates an oil-path switching valve, and required flow volume. Schematic sectional view showing the state of the oil passage switching valve in the full discharge mode Sectional view showing the operation of the check valve in full discharge mode Schematic sectional view showing the state of the oil passage switching valve in the middle discharge mode Sectional view showing the operation of the check valve in the middle discharge mode Schematic sectional view showing the state of the oil passage switching valve in the small discharge mode Sectional view showing the operation of the check valve in the small discharge mode Schematic sectional view showing the state of the oil passage switching valve in the middle discharge mode according to the second embodiment Schematic sectional view showing the state of the oil passage switching valve in the full discharge mode Schematic sectional view showing the state of the oil passage switching valve in the small discharge mode Schematic sectional drawing which shows the state of the oil-path switching valve at the time of the small discharge mode by 3rd Embodiment Schematic sectional view showing the state of the oil passage switching valve in the full discharge mode Schematic sectional view showing the state of the oil passage switching valve in the middle discharge mode Schematic sectional view showing the state of the oil passage switching valve in the middle discharge mode according to the fourth embodiment

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
{First embodiment}
1 to 9 show a first embodiment of the present invention. In the present embodiment, a state in which the flow control device is incorporated in a hydraulic control system provided in an automatic transmission such as a continuously variable transmission will be described as an example.

  In the automatic transmission, an oil pump 1 as a fluid pump that drives an engine, which is an example of a drive system, as a power source, and an oil path switch that switches an oil path of oil, which is an example of fluid discharged from the oil pump 1, are provided. There is provided a valve 2 and a control valve 3 as a control mechanism for generating a line pressure, a pilot pressure or the like using the pump flow rate discharged from the oil passage switching valve 2 as a source pressure and performing a shift control of the automatic transmission. ing. Further, the control valve 3 is provided with an oil passage switching solenoid 3a for setting a control pressure Pc for supplying the oil passage switching valve 2 to switch the oil passage.

  The oil pump 1 is a rotary pump such as a vane pump, a gear pump, or a trochoid pump, and a suction-side oil reservoir chamber 1b is formed on the suction side of a pump casing 1a of the oil pump 1. The discharge side includes a discharge side first oil reservoir chamber (hereinafter abbreviated as “first oil reservoir chamber”) 1 c and a discharge side second oil reservoir chamber (hereinafter abbreviated as “second oil reservoir chamber”) 1 d. The first oil reservoir chamber 1c is formed in a shape that can secure a larger discharge amount than the second oil reservoir chamber 1d. A suction port (not shown) communicating with the suction-side oil reservoir chamber 1 b is communicated with an oil strainer 5 disposed at the bottom of the oil pan 4 via a suction oil passage 6. A first discharge port and a second discharge port (both not shown) are communicated with the first oil reservoir chamber 1c and the second oil reservoir chamber 1d.

The oil passage switching valve 2 has a casing 7 and a spool 8 as a valve body that moves forward and backward in the casing 7. The casing 7 has a first inflow port 7a and a second inflow port 7b formed substantially at the center thereof, and a first discharge port 7c and a second discharge port 7d formed on both sides thereof. Each port 7a-7d is arrange | positioned at equal intervals. Further, a supply port 7e is formed in the middle of the first inflow port 7a and the second inflow port 7b of the casing 7. Further, a first operation chamber 7f and a second operation chamber 7g are formed at both ends of the casing 7.
Further, a substantially cylindrical first land portion 8b and a second land portion 8c are formed on the spool shaft 8a of the spool 8, and can be moved back and forth in the operation chambers 7f and 7g formed in the casing 7. A first piston portion 8d and a second piston portion 8e that are inserted are formed.

  Further, first and second compression springs 9a and 9b as operation springs that press and urge the piston portions 8d and 8e are interposed in the operation chambers 7f and 7g. These compression springs 9a and 9b are set to the same set load. As shown in FIG. 4, when the control pressure Pc is not supplied to both the operation chambers 7f and 7g, the spool 8 is kept in the neutral position. Be drunk. Further, the movement amount of the spool 8 is restricted by the shaft end portions 8f and 8g of the spool shaft 8a protruding from the end surfaces of the piston portions 8d and 8e to the operation chambers 7f and 7g contacting the operation chambers 7f and 7g. Is done.

  The first inflow port 7a formed in the casing 7 is communicated with the first discharge port communicating with the first oil reservoir 1c of the oil pump 1 through the first discharge oil passage 10a, and the second The inflow port 7b is communicated with the second discharge port communicating with the second oil reservoir chamber 1d via the second discharge oil passage 10b. Further, the first discharge port 7c and the second discharge port 7d are communicated with the suction oil passage 6 via the discharge oil passages 11a and 11b. A supply port 7 e is communicated with the control valve 3 via a supply oil passage 12.

  The control valve 3 generates a line pressure, a pilot pressure Pp, and the like for performing a shift control of an automatic transmission such as a CVT, using the supplied oil flow rate (pump flow rate) as a source pressure. The oil path switching solenoid 3a incorporated in the control valve 3 is a control that supplies the pilot chamber Pf to the operation chambers 7f and 7g of the oil path switching valve 2 in accordance with an instruction pressure from the control unit 21 described later using the pilot pressure Pp as a source pressure. A pressure Pc is generated.

  The downstream side of the control pressure oil passage 13 communicating with the upstream side to the discharge side of the oil passage switching solenoid 3a is bifurcated to communicate with the first operation chamber 7f and the second operation chamber 7g of the oil passage switching valve 2. Yes.

  A check valve 14 is interposed between the branch portion of the control pressure oil passage 13 and the first operation chamber 7f. The check valve 14 regulates the control pressure Pc flowing through the first working chamber 7f, and the check valve 14 has a spool valve body 15 and a check spring 16 as shown in FIG. The spool valve body 15 has a small diameter portion 15a and a large diameter portion 15b, a protrusion 15c is formed at the tip of the small diameter portion 15a, and a spring accommodating portion 15d is formed in a concave shape on the large diameter portion 15b. .

  On the other hand, a check oil passage 14a communicating with the control pressure oil passage 13 is connected upstream of the check valve 14, and a check pressure oil passage 14b and a control pressure passage oil passage 14c are branched from the check oil passage 14a. Yes. The check pressure oil passage 14b communicates with the hydraulic operation chamber 14d, and the control pressure passage oil passage 14c communicates with the spring chamber 14e. A small diameter portion 15a of the spool valve body 15 is inserted into the hydraulic operation chamber 14d so as to be able to advance and retreat, and a large diameter portion 15b is inserted into the spring chamber 14e.

  Further, a supply / discharge port 14f communicating with the first operating chamber 7f of the oil passage switching valve 2 and a drain port 14g are formed in the spring chamber 14e. The check spring 16 accommodated in the spring chamber 14e constantly urges the spool valve body 15 in the direction of the hydraulic operation chamber 14d. In this state, the protruding portion 15c protruding from the tip of the small diameter portion 15a. Abuts against the wall surface of the hydraulic operation chamber 14d to secure a minimum space in the hydraulic operation chamber 14d. Further, the control pressure passage oil passage 14c and the spring chamber 14e are blocked by the large diameter portion 15b. The spring pressure Pb of the check spring 16 is set between an intermediate control pressure Pl and a maximum control pressure Ps set by a control unit 21 described later (see FIG. 3B).

  Further, the pressure receiving area of the first piston portion 8d inserted through the first operation chamber 7f of the oil passage switching valve 2 is set larger than the pressure receiving area of the second piston portion 8e (8d> 8e). Therefore, as shown in FIG. 8, when the control pressure Pc opens the check valve 14 and flows into the first operation chamber 7f, the pressure receiving area of the first piston portion 8d is larger than the pressure receiving area of the second piston portion 8e. Therefore, the second piston portion 8e is pushed back by the differential pressure.

  The control pressure Pc discharged from the oil passage switching solenoid 3a provided in the control valve 3 includes a minimum control pressure (Pc = 0) that allows all draining without supplying hydraulic pressure to the control pressure oil passage 13, and a check valve 14. Are set in three stages: an intermediate control pressure Pl smaller than the spring pressure Pb of the check spring 16 and a maximum control pressure Ps larger than the spring pressure of the check spring 16.

  As shown in FIG. 4, when the spool 8 is in the neutral position, the first inflow port 7a, the second inflow port 7b, and the supply port 7e are located between the first land portion 8b and the second land portion 8c. It settles and becomes a communication state. As shown in FIG. 6, when the control pressure Pc set to the intermediate control pressure Pl is applied to the second working chamber 7g, the first inflow port 7a and the supply port 7e are connected to the first land portion. 8b and the second land portion 8c are in communication with each other, and the second inflow port 7b and the second discharge port 7d are between the second land portion 8c and the second piston portion 8e. Communicated. Furthermore, as shown in FIG. 8, when the control pressure Pc set to the maximum control pressure is applied to the first working chamber 7f, the first discharge port 7c and the first inflow port 7a are connected to the first piston. The second inflow port 7b and the second discharge port 7d are accommodated between the second land portion 8c and the second piston portion 8e and communicated with each other between the portion 8d and the first land portion 8b. Is done.

  The oil passage switching solenoid 3a for supplying the control pressure Pc for controlling the switching operation of the oil passage switching valve 2 is a duty solenoid, and the duty ratio for operating the oil passage switching solenoid 3a is set by the control unit 21. The The control unit 21 is mainly composed of a microcomputer, and a duty ratio for generating a predetermined control pressure Pc is set according to a control program stored in the CPU. The control unit 21 includes a necessary flow rate calculation unit 22, a threshold value calculation unit 23, and a switching determination calculation unit 24 as functions for controlling the control pressure Pc discharged from the oil passage switching solenoid 3a.

  The required flow rate calculation unit 22 includes an engine torque TE / G obtained by an engine torque calculation unit 31 of an engine control unit (not shown), a target speed ratio io obtained by a target gear ratio calculation unit 32 of a transmission control unit (not shown), and engine rotation. Based on the required flow rate calculation information such as the engine speed Ne detected by the number sensor 33, the oil temperature Ta in the automatic transmission detected by the oil temperature sensor 34, the hydraulic pressure Pa in the automatic transmission detected by the hydraulic sensor 35, etc. Determine the total amount of oil flow required by the machine (required flow rate) Qreg.

  Based on the engine speed Ne obtained by the engine speed sensor 33, the threshold value calculation unit 23 refers to a calculation formula or a threshold value table stored in advance in the ROM, and performs a basic small flow rate threshold value Qs and a large flow rate threshold value. Ql is set, and the oil temperature correction and the oil pressure correction are performed by the oil temperature Ta in the automatic transmission detected by the oil temperature sensor 34 and the oil pressure Pa detected by the oil pressure sensor 35, and the final small flow rate threshold value is set. Qs and a large flow rate threshold value Ql are obtained. As shown in FIG. 3 (a), the small flow rate threshold value Qs and the large flow rate threshold value Ql have characteristics that increase as the engine speed Ne increases, and the oil pump 1 is controlled by the threshold values Qs and Ql. The discharge mode Mp supplied to the control valve 3 is the small discharge mode Ms as the first discharge mode in which only the second oil reservoir chamber 1d is set, and the medium discharge mode Mm as the second discharge mode in which only the first oil reservoir chamber 1c is set. And the first oil reservoir chamber 1c and the second oil reservoir chamber 1d.

  The switching determination calculation unit 24 compares the required flow rate Qreg obtained by the required flow rate calculation unit 22 with the small flow rate threshold value Qs and the large flow rate threshold value Ql obtained by the threshold value calculation unit 23, and the required flow rate Qreg is in any discharge mode Ms. , Mm, Ml, and a duty ratio drive signal corresponding to the set control pressure Pc is output to the oil passage switching solenoid 3a.

  Specifically, the oil path switching determination processing of the oil pump 1 executed by the switching determination calculation unit 24 is performed according to a switching determination processing routine shown in FIG.

  This routine is executed every predetermined calculation cycle after the control unit 21 is activated. First, in step S1, based on the set position of the select lever detected by the select position sensor 36 that detects the set position of the select lever, It is checked whether or not the select lever is set to the D range. If it is set to the D range, the process proceeds to step S2, and if it is set to a position other than the D range, the process jumps to step S5.

  In step S2, the required flow rate Qreg is compared with the small flow rate threshold value Qs. If Qreg> Qs, the flow advances to step S3. If Qreg ≦ Qs, the process branches to step S4, the discharge mode Mp is set to the small discharge mode Ms (Mp ← Ms), and the routine is exited.

  When the discharge mode Mp is set to the small discharge mode Ms, the switching determination calculation unit 24 controls the oil path switching solenoid 3a to a maximum control larger than the spring pressure Pb of the check spring 16 provided in the check valve 14. A drive signal having a predetermined duty ratio for generating the pressure Ps (see FIG. 3B) is output. Then, the maximum control pressure Ps is discharged from the oil path switching solenoid 3a, and this maximum control pressure Ps flows into the second operation chamber 7g via the control pressure oil path 13 and also passes through the check pressure oil path 14b of the check valve 14. Then, it flows into the hydraulic operation chamber 14d.

  Since the control pressure Pc flowing into the hydraulic operation chamber 14d is set to a maximum control pressure Ps that is larger than the spring pressure Pb, the spool valve body 15 resists the biasing force of the check spring 16 as shown in FIG. Then, the drain port 14g is shut off, and the control pressure passage oil passage 14c and the spring chamber 14e are communicated with each other. Then, the control pressure Pc flowing from the check oil passage 14a flows into the first operation chamber 7f from the supply / discharge port 14f through the spring chamber 14e.

  In this case, the pressure receiving area of the first piston portion 8d inserted into the first working chamber 7f is larger than the pressure receiving area of the second piston portion 8e, and the compression is interposed in both the working chambers 7f and 7g. Since the springs 9a and 9b have the same set load, the first piston portion 8d moves the spool 8 to the second operation chamber 7g side, and the shaft end portion 8g facing the second operation chamber 7g of the spool shaft 8a. Abuts against the wall surface and the movement stops.

  Then, as shown in FIG. 8, the first inflow port 7a that communicates with the first oil reservoir 1c and the first exhaust port 7c that communicates with the exhaust oil passage 11a are connected to the first piston portion 8d and the first land portion 8b. The oil discharged from the first oil reservoir 1c is returned to the suction port side of the oil pump 1. A second inflow port 7b and a supply port 7e communicating with the second oil reservoir chamber 1d are accommodated between the first land portion 8b and the second land portion 8c, and a small discharge pump is supplied from the second oil reservoir chamber 1d. The flow rate is supplied to the control valve 3 through the supply port 7e.

  On the other hand, when the process proceeds to step S3, the required flow rate Qreg and the large flow rate threshold value Ql are compared. If Qreg> Ql, the process proceeds to step S5. If Qreg ≦ Q1, the process branches to step S6, the discharge mode Mp is set to the medium discharge mode Mm (Mp ← Mm), and the routine is exited.

  When the discharge mode Mp is set to the middle discharge mode Mm, the switching determination calculation unit 24 performs intermediate control with respect to the oil path switching solenoid 3a that is smaller than the spring pressure Pb of the check spring 16 provided in the check valve 14. A drive signal having a predetermined duty ratio for generating the pressure Pl (see FIG. 3B) is output. Then, the intermediate control pressure Pl is discharged from the oil passage switching solenoid 3a, and this intermediate control pressure Pl is applied from the control pressure oil passage 13 to the second operating chamber 7g and the check valve 14. Since the control pressure Pc is set to an intermediate control pressure Pl smaller than the spring pressure Pb, the spool valve body 15 is pushed back to the initial position by the pressing force of the check spring 16 as shown in FIG. The oil passage 14c and the spring chamber 14e are shut off, and the drain port 14g is opened.

  As a result, the hydraulic pressure in the first operating chamber 7f is discharged from the drain port 14g via the spring chamber 14e, and the control pressure Pc is supplied only to the second operating chamber 7g. The shaft end portion 8f of the spool shaft 8a facing the first operation chamber 7f comes into contact with the wall surface and stops moving. Then, as shown in FIG. 6, the first inflow port 7a and the supply port 7e communicating with the first oil reservoir 1c are accommodated between the first land portion 8b and the second land portion 8c, and the first A medium discharge pump flow rate is supplied from the oil reservoir 1c to the control valve 3 via the supply port 7e. On the other hand, a second inflow port 7b and a second discharge port 7d communicating with the second oil reservoir chamber 1d are accommodated between the second land portion 8c and the second piston portion 8e, so that the second oil reservoir chamber 1d The discharged oil is returned to the suction port side of the oil pump 1.

  In step S5, the discharge mode Mp is set to the full discharge mode Ml (Mp ← Ml), and the routine is exited. As a result, the switching determination calculation unit 24 outputs a signal for draining the pilot pressure Pp to the oil passage switching solenoid 3a. Then, the supply of the control pressure Pc from the oil path switching solenoid 3a to the control pressure oil path 13 is cut off, and the control pressure Pc flowing into the second operation chamber 7g passes through the control pressure oil path 13 and the oil path switching solenoid. Drained from the 3a side. On the other hand, in the check valve 14, since the spool valve body 15 receives the biasing force of the check spring 16 and is pushed back to the initial position, the control pressure Pc supplied to the first operation chamber 7f is supplied from the supply / discharge port 14f to the spring chamber 14e. And then discharged from the drain port 14g.

  Then, since the control pressure Pc of both the operating chambers 7f and 7g is drained, both the operating chambers 7f and 7g are just balanced by the urging forces of the compression springs 9a and 9b having the same set load, that is, as shown in FIG. In this way, the first inflow port 7a, the second inflow port 7b, and the supply port 7e are stopped at a position where they are accommodated in the first land portion 8b and the second land portion 8c. Then, a large discharge pump flow rate obtained by adding the medium discharge pump flow rate from the first oil reservoir chamber 1c and the small discharge pump flow rate from the second oil reservoir chamber 1d is supplied to the control valve 3 via the supply port 7e. Is done.

  In this way, in this embodiment, the pump flow rate can be switched in three stages in accordance with the required flow rate Qreg of the automatic transmission, so that the pump flow rate can be optimally divided and the oil pump 1 It is possible to secure a sufficient control region in the whole, and wasteful power loss is reduced, so that fuel efficiency can be further improved.

[Second Embodiment]
10 to 12 show a second embodiment of the present invention. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Moreover, the switching determination process applies the switching determination process routine shown in FIG. 2 as it is, and only the process different from the first embodiment will be described.

  In the first embodiment described above, the compression springs 9a and 9b accommodated in both the operation chambers 7f and 7g of the oil passage switching valve 2 are set to the same set load, and therefore controlled from the oil passage switching solenoid 3a. In a state in which the pressure Pc is not supplied, the spool 8 is set to the neutral position as shown in FIG. 4 so that the maximum discharge pump flow rate is supplied to the control valve 3.

  On the other hand, in this embodiment, the set load of the second compression spring 9b is made larger than the set load of the first compression spring 9a, and the check valve 14 is omitted. Therefore, in the initial state in which the control pressure Pc is not supplied to both the operation chambers 7f and 7g, as shown in FIG. 10, the spool 8 is moved to the first operation chamber 7f side by the second compression spring 9a of the second operation chamber 7g. Therefore, the discharge mode Mp in this state is the middle discharge mode Mm in which the pump flow rate is supplied from the first oil reservoir 1c of the oil pump 1 to the control valve 3.

  That is, in step S3 of the switching determination processing routine shown in FIG. 2, when it is determined that Qreg ≦ Qs, the process proceeds to step S4 and the discharge mode Mp is set to the small discharge mode Ms (Mp ← Ms). 24 outputs a drive signal of a predetermined duty ratio that causes the oil path switching solenoid 3a to generate the maximum control pressure Ps. The maximum control pressure Ps is a value obtained by adding the spring pressure of the first compression spring 9a and the received pressure generated in the first piston portion 8d, and adding the received pressure generated in the second compression spring 9b and the second piston portion 8e. It is set to a value that is larger than the value.

  Then, the maximum control pressure Ps is discharged from the oil passage switching solenoid 3a, and this maximum control pressure Ps is supplied to both the first operation chamber 7f and the second operation chamber 7g.

  As a result, as shown in FIG. 12, the first piston portion 8d having a large pressure receiving area presses the spool 8 against the urging force of the second compression spring 9b in the direction of the second operation chamber 7g, and the first oil reservoir The first inflow port 7a that communicates with the chamber 1c and the first exhaust port 7c that communicates with the discharge oil passage 11a communicate with each other and return to the suction port side of the oil pump 1. Further, the second inflow port 7b communicating with the second oil reservoir chamber 1d and the supply port 7e are connected to supply a small discharge pump flow rate from the second oil reservoir chamber 1d to the control valve 3. The control pressure Ps supplied to the second operation chamber 7g is pushed out from the control pressure oil passage 13 to the first operation chamber 7f side.

  On the other hand, when it is determined in step S3 of the flowchart shown in FIG. 2 that Qreg ≦ Ql and the process proceeds to step S6, and the discharge mode Mp is set to the middle discharge mode Mm, the switching determination calculation unit 24 operates the oil path switching solenoid. A signal for draining the pilot pressure Pp is output to 3a, the supply of the control pressure Pc from the oil passage switching solenoid 3a to the control pressure oil passage 13 is cut off, and the first operation chamber 7f and the second operation chamber 7g are supplied. The inflow control pressure Pc is drained from the oil path switching solenoid 3a side.

  As a result, as shown in FIG. 10, the spool 8 receives the urging force of the second compression spring 9b, slides toward the first operating chamber 7f, and supplies the first inflow port 7a communicating with the first oil reservoir 1c. The port 7e is communicated, and the medium discharge pump flow rate is supplied to the control valve 3 via the supply port 7e. On the other hand, the second inflow port 7b and the second discharge port 7d communicating with the second oil reservoir chamber 1d are communicated, and the oil discharged from the second oil reservoir chamber 1d is returned to the suction port side of the oil pump 1. .

  Further, when Qreg> Ql is determined in step S3 of the flowchart shown in FIG. 2 and the process proceeds to step S5 and the discharge mode Mp is set to the full discharge mode Ml (Mp ← Ml), the switching determination calculating unit 24 A drive signal having a predetermined duty ratio for generating the intermediate control pressure Pl is output to the switching solenoid 3a. Then, the intermediate control pressure Pl discharged from the oil passage switching solenoid 3a is supplied to the first operating chamber 7f and the second operating chamber 7g.

  The intermediate control pressure Pl is a value obtained by adding the pressure received in the first piston portion 8d to the spring pressure of the first compression spring 9a in the first operation chamber 7f, and the spring of the second compression spring 9b in the second operation chamber 7g. The pressure is set to a value equal to the value obtained by adding the pressure received in the second piston portion 8e. As a result, as shown in FIG. 11, the spool 8 stops at the center, and the first inflow port 7a, the second inflow port 7b, and the supply port 7e communicate with each other, and the medium discharge from the first oil reservoir 1c is performed. A large discharge pump flow rate obtained by adding the pump flow rate and the small discharge pump flow rate from the second oil reservoir 1 d is supplied to the control valve 3.

  Thus, in this embodiment, since the check valve 14 is omitted as compared with the first embodiment, the structure can be simplified.

[Third Embodiment]
13 to 15 show a third embodiment of the present invention. Note that the same components as those of the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, as for the switching determination process, the switching determination processing routine shown in FIG. 2 is applied as it is, and only the processing different from the second embodiment will be described.

  In the second embodiment described above, the pressure receiving area of the first piston portion 8d inserted through the first operation chamber 7f is set larger than that of the second piston portion 8e inserted through the second operation chamber 7g. The spring pressure of the second compression spring 9b is set to be larger than the spring pressure of the first compression spring 9a. In this embodiment, the pressure receiving area of the second piston portion 8e inserted through the second operating chamber 7g. Is set larger than the first piston portion 8d inserted through the first operation chamber 7f, and the spring pressure of the first compression spring 9a is set larger than the spring pressure of the second compression spring 9b.

  Therefore, as shown in FIG. 13, in the initial state where the control pressure Pc is not applied to both the operation chambers 7f and 7g, the spring pressure of the first compression spring 9a in which the spool 8 is interposed in the first operation chamber 7f. Is slid toward the second operating chamber 7g, and the shaft end 8g of the spool shaft 8a is in contact with the wall surface.

  In this initial state, FIG. 12 of the second embodiment, that is, the first inflow port 7a communicating with the first oil reservoir 1c of the oil pump 1 and the first exhaust port 7c communicating with the exhaust oil passage 11a are communicated. Further, the second inflow port 7b communicating with the second oil reservoir chamber 1d and the supply port 7e communicate with each other, and the small discharge mode in which the small discharge pump flow rate is supplied to the control valve 3 from the second oil reservoir chamber 1d. It is set to Ms.

  Therefore, in step S2 of the flowchart of FIG. 2, when it is determined that Qreg ≦ Qs, the process branches to step S4, and the discharge mode Mp is set to the small discharge mode Ms (Mp ← Ms), the switching determination calculation unit 24 A signal for draining the pilot pressure Pp is output to the oil passage switching solenoid 3a, the supply of the control pressure Pc from the oil passage switching solenoid 3a to the control pressure oil passage 13 is cut off, and the first operating chamber 7f, second The control pressure Pc flowing into the operation chamber 7g is drained from the oil passage switching solenoid 3a side, and the initial state shown in FIG. 13 is maintained by the spring pressure difference between the compression springs 9a and 9b.

  In step S3, it is determined that Qreg> Ql, and the process proceeds to step S5. When the discharge mode Mp is set to the full discharge mode Ml (Mp ← Ml), the switching determination calculating unit 24 applies to the oil path switching solenoid 3a. Thus, a drive signal having a predetermined duty ratio for generating the intermediate control pressure Pl is output. Then, the intermediate control pressure Pl discharged from the oil passage switching solenoid 3a is supplied to the first operating chamber 7f and the second operating chamber 7g.

  The intermediate control pressure Pl is a value obtained by adding the pressure received in the first piston portion 8d to the spring pressure of the first compression spring 9a in the first operation chamber 7f, and the spring of the second compression spring 9b in the second operation chamber 7g. The pressure is set to a value equal to the value obtained by adding the pressure received in the second piston portion 8e. Therefore, as shown in FIG. 14, the spool 8 stops at the center, and the first inflow port 7a, the second inflow port 7b, and the supply port 7e are communicated with each other, and the medium discharge pump from the first oil reservoir 1c. A large discharge pump flow rate obtained by adding the flow rate and the small discharge pump flow rate from the second oil reservoir chamber 1 d is supplied to the control valve 3.

  On the other hand, if it is determined in step S3 that Qreg ≦ Ql and the process proceeds to step S6, and the discharge mode Mp is set to the middle discharge mode Mm, the switching determination calculation unit 24 applies the maximum control pressure to the oil path switching solenoid 3a. A drive signal having a predetermined duty ratio for generating Ps is output. The maximum control pressure Ps is a value obtained by adding the spring pressure of the second compression spring 9b and the pressure received in the second piston portion 8e, and adding the pressure received in the first compression spring 9a and the first piston portion 8d. It is set to a value that is larger than the value.

  As a result, as shown in FIG. 15, the spool 8 receives the urging force by the maximum control pressure Ps supplied to the second operation chamber 7g, slides toward the first operation chamber 7f, and enters the first oil reservoir 1c. The first inflow port 7a and the supply port 7e that communicate with each other are connected to supply the medium discharge pump flow rate to the control valve 3 through the supply port 7e. On the other hand, the second inflow port 7b and the second discharge port 7d communicating with the second oil reservoir chamber 1d are communicated, and the oil discharged from the second oil reservoir chamber 1d is returned to the suction port side of the oil pump 1. . The control pressure Ps supplied to the first operation chamber 7f is pushed out from the control pressure oil passage 13 to the second operation chamber 7g side.

  Thus, in this embodiment, since the check valve 14 is omitted, the structure can be simplified as in the second embodiment described above.

[Fourth Embodiment]
FIG. 15 shows a fourth embodiment of the present invention. In addition, about the same component as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the first to third embodiments described above, the spool 8 of the oil passage switching valve 2 is operated by hydraulic control, but the oil passage switching valve 2 ′ according to the present embodiment is an oil passage using the spool 8 as an electromagnetic actuator. A control operation is directly performed by the switching solenoid 41. The operation of the oil path switching solenoid 41 is performed by the control unit 21 of the first embodiment, and the oil path switching solenoid 3a shown in FIG.

  The oil passage switching solenoid 41 is provided on the first operation chamber 7f side of the oil passage switching valve 2 ', and when stopped, receives the urging force of the compression spring 9b provided in the second operation chamber 7g to perform the first operation. It is pressed to the chamber 7f side. This state is the same as the initial position shown in FIG. 10 of the second embodiment, and the switching determination calculation unit 24 sets the discharge mode Mp to the middle discharge mode Mm (S6 in FIG. 2), and the duty ratio with respect to the oil path switching solenoid 41. Is set to 0 [%].

  On the other hand, when the switching determination calculation unit 24 sets the discharge mode Mp to the full discharge mode Ml (S5 in FIG. 2), the drive signal of the intermediate duty ratio is transmitted to the oil passage switching solenoid 41, and the spool 8 is connected to the second compression spring. 9 b against the urging force of 9 b, slides toward the second operation chamber 7 g, stops at the same position as in FIG. 11, and discharges the medium discharge pump from the first oil reservoir 1 c and the second oil reservoir 1 d. A large discharge pump flow rate is added to the control valve 3.

  When the switching determination calculation unit 24 sets the discharge mode Mp to the small discharge mode Ms (S4 in FIG. 2), the drive signal of the maximum duty ratio is transmitted to the oil path switching solenoid 41, and the shaft end 8g of the spool 8 is transmitted. Is brought into contact with the wall surface of the second operation chamber 7g and stopped. Accordingly, the second inflow port 7b communicating with the second oil reservoir chamber 1d and the supply port 7e are communicated, and a small discharge pump flow rate is supplied to the control valve 3 from the second oil reservoir chamber 1d.

  Thus, in this embodiment, since the spool 8 of the oil passage switching valve 2 ′ is directly moved by the oil passage switching solenoid 41, the responsiveness is better than that in the second embodiment, and the hydraulic pressure is changed. Since the number of circuits is reduced, the structure can be simplified.

  The present invention is not limited to the above-described embodiment. For example, the oil passage switching valve 2 ′ of the fourth embodiment is provided with the oil passage switching solenoid 41 in the first operation chamber 7f. The solenoid 41 may be provided on the second operating chamber 7g side, and the second operating chamber 7g may press and urge the spool 8 toward the side by a first compression spring 9a provided in the first operating chamber 7f. In this case, the switching determination calculation unit 24 performs the same control as that of the third embodiment described above.

1 ... oil pump,
1a ... pump casing,
1b: Oil reservoir on the suction side,
1c: first oil reservoir,
1d: second oil reservoir,
2, 2 '... oil passage switching valve,
3 ... Control valve,
3a: oil passage switching solenoid,
7 ... casing,
7a ... 1st inflow port,
7b ... second inflow port,
7c ... 1st discharge port,
7d ... second discharge port,
7e ... supply port,
7f ... the first working chamber,
7g ... the second working chamber,
8 ... Spool,
8a ... spool shaft,
8b ... 1st land part,
8c ... 2nd land part,
8d ... 1st piston part,
8e ... 2nd piston part,
10a ... 1st discharge oil path,
10b ... second discharge oil passage,
11a ... Oil discharge path,
12 ... Supply oil passage,
13 ... Control pressure oil passage,
14 ... Check valve,
15 ... Spool valve body,
21 ... Control unit,
22: Necessary flow rate calculation unit,
23: Threshold value calculation unit,
24 ... switching determination calculation unit,
33. Engine speed sensor,
41 ... oil passage switching solenoid,
Ml: All discharge mode,
Mm: Medium discharge mode,
Mp: Discharge mode,
Ms: small discharge mode,
Ne ... engine speed,
Pa ... Hydraulic,
Pb ... spring pressure,
Pc: control pressure,
Pl: Intermediate control pressure,
Ps: Maximum control pressure,
Qreg ... required flow rate,
Ql ... Large flow rate threshold,
Qs: Small flow rate threshold

Claims (5)

The pump casing is formed with a suction-side oil reservoir chamber, a discharge-side first oil reservoir chamber, and a discharge-side second oil reservoir chamber, and the fluid sucked from the suction-side oil reservoir chamber in accordance with the operation of the drive system. A fluid pump to be discharged into the chamber;
A first inflow port that communicates with the discharge-side first oil reservoir, a second inflow port that communicates with the discharge-side second oil reservoir, and a supply port that communicates with the control mechanism driven by the drive system And an oil passage switching valve having a valve body for switching the flow rate of fluid supplied to the control mechanism by communicating each inflow port and the supply port;
A flow rate control device for a fluid pump, comprising: a control unit that controls switching of the oil passage switching valve and controls a fluid flow rate supplied to the control mechanism;
The oil passage switching valve can selectively communicate the first inflow port and the second inflow port to the supply port or both the inflow port to the supply port by the switching operation of the valve body. And
The control unit includes a first discharge mode for communicating the first inflow port and the supply port, a second discharge mode for communicating the second inflow port and the supply port, the two inflow ports, and the supply port. A flow rate control device for a fluid pump, wherein one discharge mode is selected from all discharge modes to be communicated according to a fluid flow rate required by the control mechanism. The first oil reservoir chamber is set to have a larger capacity than the second oil reservoir chamber,
The control unit compares the required flow rate with a small flow rate threshold value and a large flow rate threshold value, and if the required flow rate is less than or equal to the small flow rate threshold value, selects the first discharge mode. 2. The second discharge mode is selected when it is between a large flow rate threshold value and the full discharge mode is selected when the required flow rate exceeds the large flow rate threshold value. The flow control apparatus of the fluid pump as described. The drive train is an engine;
The flow rate control device for a fluid pump according to claim 2, wherein each of the flow rate determination threshold values is variably set based on the number of revolutions of the engine. The control unit sets a control pressure discharged from the hydraulic actuator,
The flow control device for a fluid pump according to any one of claims 1 to 3, wherein the valve body of the oil passage switching valve is switched by the control pressure in accordance with each of the discharge modes. An electromagnetic actuator is connected to the valve body of the switching valve,
The flow control device for a fluid pump according to any one of claims 1 to 3, wherein the control unit switches the valve body according to each of the discharge modes via the electromagnetic actuator.

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