JP2016098732A - Pressure adjusting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rationally configure a pressure adjusting system capable of enhancing operation efficiency of a pump independent of viscosity of working fluid.SOLUTION: A pressure adjusting system includes: an oil pump 1 having a suction port 31, and a first discharge port 32 and a second discharge port 33; a feed flow passage 14; a return flow passage 16; a relief valve 4 having a valve element 40, a spring 44, and a pressure chamber 45 provided in a storage space of the spring 44, and capable of being switched between a first state in which working fluid discharged from the second discharge port 33 is merged with the working fluid discharged from the first discharge port 32 and a second state in which the working fluid discharged from the second discharge port 33 is returned to the return flow passage 16 in accordance with movement of the valve element 40; and a solenoid valve 5 disposed in a branch flow passage 15 which is branched from the feed flow passage 14 through which the working fluid discharged from the first discharge port 33 flows and is connected with the pressure chamber 45, and controlling supply of the working fluid to the pressure chamber 45.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure adjustment system that adjusts the discharge pressure of an oil pump.

  2. Description of the Related Art Conventionally, a pressure adjustment system that adjusts the discharge pressure of an oil pump that circulates hydraulic oil to a supply portion of an engine is known (for example, see Patent Document 1).

  The pressure adjustment system described in Patent Document 1 includes an oil pump having a suction port, a first discharge port, and a second discharge port, a valve body that receives the pressure of hydraulic oil discharged from the first discharge port, And a control valve for circulating hydraulic oil discharged from the two discharge ports. The control valve has a first configuration for joining the hydraulic oil discharged from the second discharge port to the hydraulic oil discharged from the first discharge port, and the first discharge port and the second discharge as the valve body moves. It is configured to be switchable between an intermediate form for relieving the hydraulic oil discharged from the port and a second form for relieving only the hydraulic oil discharged from the second discharge port.

  When the engine speed increases, the hydraulic oil discharged from the first discharge port and the second discharge port is relieved by shifting from the first form to the intermediate form, so that the gradient of the pump discharge pressure rises gently. Become. When the engine speed further increases, the discharge pressure of the pump rapidly increases by shifting to the second mode in which relief of the hydraulic oil discharged from the first discharge port is shut off. In other words, the pressure adjustment system described in Patent Document 1 is a technology that increases the fuel consumption by reducing an unnecessary work amount of the pump by providing an intermediate configuration for reducing the discharge amount of the pump.

JP-A-8-114186

  By the way, when the temperature of the hydraulic oil is low and the viscosity is high, a relatively large pressure is applied to the supplied portion of the engine, so that the discharge pressure of the pump can be set to a low pressure as the engine speed increases. There is a wide area. However, in the pressure adjustment system described in Patent Document 1, when the hydraulic oil has a high viscosity, the pressure acting on the valve body increases, so that the intermediate configuration can be obtained at an early stage before the engine speed reaches the desired speed. Will shift to the second form. As a result, since the region where the discharge pressure of the pump is set to a low pressure is narrowed, the effect of reducing the pump work is small, and there is room for improvement in improving fuel consumption.

  Therefore, an object of the present invention is to rationally configure a pressure adjustment system that can increase the operation efficiency of the pump regardless of the viscosity of the hydraulic oil.

  The characteristic configuration of the pressure adjustment system according to the present invention includes an oil pump having a suction port to which hydraulic oil is supplied, a first discharge port and a second discharge port from which hydraulic oil is discharged, and the first discharge port. A supply flow path for supplying the discharged hydraulic oil to the supplied part, a return flow path for returning the hydraulic oil discharged from the second discharge port to the suction port or the oil pan, and the supply flow path A valve body that receives the pressure of the hydraulic fluid that circulates, a spring that urges the valve body in a direction opposite to the pressure, and a pressure chamber that is provided in a housing space of the spring, and the movement of the valve body Accordingly, the first state in which the hydraulic oil discharged from the second discharge port merges with the hydraulic oil discharged from the first discharge port, and the hydraulic oil discharged from the second discharge port to the feedback flow Second letter to be returned to the road And a solenoid valve that is arranged in a branch flow path that branches from the supply flow path and is connected to the pressure chamber, and that controls the supply of hydraulic oil to the pressure chamber. There is in point.

  In this configuration, two discharge ports are provided, and the combined flow rate of the hydraulic oil discharged from the second discharge port is adjusted to the hydraulic oil discharged from the first discharge port. That is, if the relief amount of the hydraulic oil discharged from the second discharge port is adjusted, the supply amount of the hydraulic oil to the supply target portion of the engine increases or decreases. For example, when supplying hydraulic oil to the valve timing control device of an engine, when the operation is started and a predetermined number of revolutions is reached, the device is filled with the desired hydraulic oil. It is possible to set the pump to a low pressure setting.

  On the other hand, even if the engine speed is the same, the pressure acting on the valve body varies depending on the temperature (viscosity) of the hydraulic oil, so the first state is changed to the second state or the second state to the first state. And the switching timing is different. For example, when the hydraulic oil is cold, the viscosity is high and the high pressure acts on the valve body. Therefore, even in the engine speed range where the pump can be set to the low pressure, the second state is quickly switched to the first state. There is a risk of shifting to a high pressure setting.

  However, in this configuration, a pressure chamber is provided in the spring accommodating space, and the supply of hydraulic oil supplied to the pressure chamber is controlled by an electromagnetic valve. For this reason, when the hydraulic oil is at a low temperature, if the electromagnetic valve is opened and hydraulic oil is supplied to the pressure chamber, the urging force of the spring is assisted to suppress the movement of the valve body, and the second state is changed to the first state. The switching timing to can be delayed. As a result, since the low pressure setting of the pump is maintained even when the hydraulic oil is at a low temperature, the wasteful work of the pump can be reduced and the fuel consumption can be improved.

  Thus, if the hydraulic oil supplied to the pressure chamber is adjusted by the electromagnetic valve, the work of the pump can be reduced regardless of the viscosity of the hydraulic oil. In addition, it is reasonable to provide a hydraulic oil supply port in the pressure chamber formed in the spring accommodating space of the control valve and connect it to the electromagnetic valve.

  Another characteristic configuration is that the solenoid valve selectively switches between a supply mode for supplying hydraulic oil to the pressure chamber and a cutoff mode for blocking supply of hydraulic oil to the pressure chamber.

  As in this configuration, the solenoid valve has a simple configuration because it is only necessary to switch between the supply mode and the cutoff mode. Further, when the hydraulic oil is at a low temperature and the engine reaches a desired rotational speed, the low pressure setting of the pump can be maintained by switching the solenoid valve to the supply mode.

  In another feature, the solenoid valve includes a supply mode for supplying hydraulic oil to the pressure chamber, and a cutoff mode for blocking supply of the hydraulic oil to the pressure chamber. The amount of hydraulic oil supplied to the pressure chamber is adjusted by controlling the amount of current supplied to the solenoid valve.

  If the amount of hydraulic oil supplied to the pressure chamber is adjusted as in this configuration, the difference from the viscosity of the hydraulic oil, i.e., the pressure acting on the valve body, causes the first state to change from the second state or from the second state. The timing for switching to the first state can be set with high accuracy.

  According to another characteristic configuration, the pressure chamber is formed with a drain port for discharging the hydraulic oil flowing therein to the outside, and an opening area of the drain port is set smaller than a cross-sectional area of the branch flow path. In the point.

  As in this configuration, if a drain port is formed in the pressure chamber and the opening area of the drain port is set smaller than the cross-sectional area of the branch flow path, the desired hydraulic oil is supplied to the pressure chamber and the pressure in the pressure chamber is reduced. While increasing moderately, the rapid pressure fluctuation by supply of hydraulic oil can be suppressed. Further, when the temperature of the hydraulic oil changes from a low temperature to a high temperature and the hydraulic oil in the pressure chamber becomes unnecessary, it is possible to drain quickly. Furthermore, this drain port can be made to function as a breathing hole accompanying the movement of the valve body, which is reasonable.

It is a whole lineblock diagram of the pressure regulation system concerning this embodiment. It is a conceptual diagram which shows the 1st state when the rotation speed of an engine is a low region. It is a conceptual diagram which shows the 2nd state when the rotation speed of an engine is a mid range. It is a conceptual diagram which shows the 1st state when the rotation speed of an engine is a mid range. It is a conceptual diagram which shows the 2nd state when the rotation speed of an engine is a high region. It is a figure which shows a control flow. It is a figure which shows the relationship between the rotation speed of the engine at the time of acceleration, and the discharge pressure of a pump. It is a figure which shows the relationship between the engine speed at the time of deceleration, and the discharge pressure of a pump. It is a figure which shows the relationship between the rotation speed of the engine at the time of acceleration, and the discharge pressure of a pump. It is a whole block diagram of the pressure regulation system which concerns on another embodiment.

  Hereinafter, an embodiment of a pressure regulation system according to the present invention will be described based on the drawings. In the present embodiment, pressure for adjusting the discharge pressure of an oil pump 1 (hereinafter simply referred to as pump 1) that circulates engine oil (an example of hydraulic oil; hereinafter simply referred to as hydraulic oil) to the engine E of the vehicle. The adjustment system X will be described as an example. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the scope of the invention.

[overall structure]
As shown in FIG. 1, the pump 1 is disposed between an oil pan 7 that stores hydraulic oil and an engine E. Circulate hydraulic oil through the section.

  The pressure adjustment system X according to the present embodiment includes a pump 1, flow paths 13 to 16, a relief valve 4 (an example of a control valve), an electromagnetic valve 5, and a control unit 9.

  The pump 1 includes a pump body 10 and a rotor 20 that is driven in synchronization with a crankshaft (not shown). The pump body 10 is formed with an internal gear portion 11 having a plurality of internal teeth, and the rotor 20 is formed with an external gear portion 21 having a plurality of external teeth having a smaller number of teeth than the internal teeth. Yes. The internal gear portion 11 and the external gear portion 21 are defined by a trochoid curve or a cycloid curve.

  A pump chamber 12 is formed between the internal gear portion 11 of the pump body 10 and the external gear portion 21 of the rotor 20, and the volume of the pump chamber 12 is the largest in the space 22k, and the space 22e and the space 22f are the largest in volume. Is configured to be small. As the rotor 20 rotates in the direction of the arrow A1, the volume increases from the space 22e to the space 22a and a suction action is obtained, and the volume decreases from the space 22j to the space 22f. The effect is obtained.

  The pump body 10 is formed with a suction port 31 through which hydraulic oil is supplied to the pump chamber 12 by a suction action, and a first discharge port 32 and a second discharge port 33 through which hydraulic oil is discharged by a discharge action. In the present embodiment, the suction port 31 is formed in a region from the space 22e to the space 22a along the rotation direction A1 of the rotor 20. The first discharge port 32 is formed in a region from the space 22j to the space 22h along the rotation direction A1, and the second discharge port 33 is formed in a region from the space 22g to the space 22f along the rotation direction A1. Has been.

  The second discharge port 33 is disposed downstream of the first discharge port 32 in the rotation direction A1, and the first discharge port 32 and the second discharge port 33 are partitioned by the partition portion 34 and have independent discharge functions. Have. The opening area of the first discharge port 32 is set larger than the opening area of the second discharge port 33, and the first discharge port 32 functions as a main port.

  As the pump 1 rotates, the hydraulic oil pumped up from the oil pan 7 is supplied to the suction port 31 of the pump 1 via the supply flow path 13. Next, at least the hydraulic oil discharged from the first discharge port 32 is supplied to the supply portion of the engine E via the supply flow path 14. At this time, the branch flow path 15 branched from the feed flow path 14 is connected to a pressure chamber 45 of the relief valve 4 to be described later, and the electromagnetic valve 5 is disposed in the middle of the branch flow path 15. In addition, a return flow path 16 is formed that returns at least the hydraulic oil discharged from the second discharge port 33 to the suction port 31 via the relief valve 4.

  The supply flow path 14 on the downstream side of the pump 1 includes a temperature sensor T and a pressure sensor P. Although details will be described later, the measurement pressure Pd of the pressure sensor P and the measurement temperature Td of the temperature sensor T are input to the control unit 9. Further, the control unit 9 is input with the actual rotational speed of the engine E measured from a rotation sensor installed on a crankshaft (not shown), load information of the engine E measured from the throttle opening degree, and the like.

  The relief valve 4 is provided in a valve body 40 that receives the pressure of the hydraulic oil flowing through the supply passage 14, a spring 44 that biases the valve body 40 in the direction B <b> 1 facing the pressure, and a housing space for the spring 44. The pressure chamber 45 is provided. In other words, the pressure chamber 45 in the present embodiment is provided in a space where the spring 44 exists. The relief valve 4 is accommodated in a common housing with the pump 1, and the valve body 40 is configured to be slidable on the inner wall of the housing. In addition, you may form the housing of the pump 1 and the relief valve 4 independently.

  The valve body 40 includes at least a first valve portion 41 that receives the pressure of the hydraulic oil discharged from the first discharge port 32, and a second valve portion 42 that receives the pressure of the hydraulic oil discharged from at least the second discharge port 33. However, the connecting members 43 are arranged to face each other. The first valve portion 41 has a first pressure receiving surface 41a and a second pressure receiving surface 41b, and the second valve portion 42 has a third pressure receiving surface 42a. Further, the second valve portion 42 has a cylindrical portion 42b formed in a bottomed cylindrical shape for holding the spring 44 at a position opposite to the third pressure receiving surface 42a. A fourth pressure receiving surface 42c that receives pressure from the hydraulic oil supplied to the pressure chamber 45 is formed in the cylindrical portion 42b.

  In the present embodiment, since the areas of the second pressure receiving surface 41b and the third pressure receiving surface 42a are set to be approximately equal, the pressure receiving surface contributing to the movement of the valve body 40 is the first pressure receiving surface 41a. The second pressure receiving surface 41b and the third pressure receiving surface 42a may have an area difference to function as a pressure receiving surface that contributes to the movement of the valve body 40.

  In addition, the relief valve 4 relieves the hydraulic fluid discharged from the second discharge port 33 to the merging port 4a for joining the feed flow passage 14 and the hydraulic oil discharged from the second discharge port 33 to the return flow passage 16. And a relief port 4b. That is, when the position of the valve body 40 is in the state shown in FIGS. 2 and 4, the merging port 4 a communicates with the supply flow path 14, and hydraulic oil discharged from the second discharge port 33 is discharged from the first discharge port 32. The first state is to join the discharged hydraulic oil. On the other hand, when the position of the valve body 40 is in the state shown in FIGS. 3 and 5, the hydraulic oil discharged from at least the second discharge port 33 is in the second state in which relief is performed via the relief port 4 b.

  In addition, a drain port 4 c that discharges hydraulic oil flowing inside to the oil pan 7 is formed in the pressure chamber 45 provided in the accommodation space of the spring 44. The opening area of the drain port 4 c is set smaller than the cross-sectional area of the branch flow path 15. As a result, it is possible to suppress rapid pressure fluctuations in the pressure chamber 45 while supplying appropriate hydraulic oil to the pressure chamber 45. Further, since the drain port 4c functions as a breathing hole, the smooth movement of the valve body 40 is not hindered.

  The electromagnetic valve 5 includes a solenoid part C and a flow path switching part D, and controls the supply of hydraulic oil to the pressure chamber 45. When a signal from the control unit 9 is received and the coil 51 of the solenoid unit C is energized, a magnetic flux is generated, and the plunger 52 attracted by the magnetic flux moves in the axial direction. The flow path switching unit D includes a spool 53 that is pushed by the plunger 52, a sleeve 54 that inserts the spool 53, and a biasing member 55 that biases the spool 53 in the direction of the solenoid C. . In the spool 53, an annular groove 53a is formed. In addition, the sleeve 54 has a supply / discharge port 54a through which hydraulic oil is supplied to and discharged from the pressure chamber 45 of the relief valve 4, a supply port 54b through which hydraulic oil flowing through the branch flow path 15 is supplied, and a supply / discharge port 54a. A drain port 54c capable of communicating is formed.

  In the state where the solenoid part C is not energized, as shown in FIG. 1, the spool 53 is positioned at the right end (solenoid part C side) by the biasing force of the biasing member 55 and is present in the pressure chamber 45 of the relief valve 4. Oil is discharged to the oil pan 7 through the supply / discharge port 54a and the drain port 54c. This is a shut-off mode in which the supply of hydraulic oil to the pressure chamber 45 is shut off. In the present embodiment, the hydraulic oil is discharged in the cutoff mode. However, the hydraulic oil may be simply stopped at the outer surface of the spool 53 and not discharged.

  On the other hand, when the solenoid portion C is energized, the plunger 52 moves the spool 53 in the left direction (the biasing member 55 side) against the biasing force of the biasing member 55. At this time, the spool 53 stops at a position where the biasing force of the biasing member 55 and the suction force of the plunger 52 are balanced. As a result, the hydraulic oil flowing through the branch flow path 15 is supplied to the pressure chamber 45 through the supply port 54b, the annular groove 53a, and the supply / discharge port 54a. This is a supply mode for supplying hydraulic oil to the pressure chamber 45.

[Adjustment of pump discharge pressure]
Next, the change in the discharge pressure of the pump 1 accompanying the movement of the valve body 40 will be described with reference to FIGS. When the operation of the pump 1 is started, as shown in FIG. 2, the valve body 40 is in the lower limit position, and the hydraulic oil discharged from the second discharge port 33 flows into the merging port 4 a and the first valve portion 41 and the second valve. It passes through the space between the parts 42 and merges with the hydraulic oil discharged from the first discharge port 32 (first state). At this time, the discharge pressure of the pump 1 is a high pressure setting (0 to N1 in FIG. 7).

  Next, the pressure of the hydraulic oil discharged from the first discharge port 32 and the second discharge port 33 is applied to the first pressure receiving surface 41 a of the valve body 40, and the valve body 40 when the urging force of the spring 44 is exceeded. Moves in the direction B2 in which it rises. As a result, the hydraulic oil discharged from the second discharge port 33 passes through the space between the first valve portion 41 and the second valve portion 42 and the relief port 4b, and passes through the return flow path 16 to the suction port. 31 (second state). At this time, as the rotational speed of the engine E increases, the rising gradient of the discharge pressure of the pump 1 becomes gentle (N1 to N2 in FIG. 7). As shown in FIG. 3, when the first valve portion 41 rises to the position of the partition portion 34, the communication between the first discharge port 32 and the second discharge port 33 is blocked, and the discharge pressure of the pump 1 is The low pressure setting depends on the pressure of only the hydraulic oil discharged from one discharge port 32 (second state, N2 to N3 in FIG. 7).

  Next, the pressure of the hydraulic oil discharged from the first discharge port 32 is applied to the first pressure receiving surface 41a of the valve body 40, and the valve body 40 further rises. As shown in FIG. 4, when a gap is generated between the first valve part 41 and the partition part 34, the hydraulic oil discharged from the second discharge port 33 is the hydraulic oil discharged from the first discharge port 32. Merge (first state). As a result, the discharge pressure of the pump 1 is set to a high pressure, and the discharge pressure of the pump 1 rapidly increases (N3 to N4 in FIG. 7).

  Next, the pressure of the hydraulic oil discharged from the first discharge port 32 and the second discharge port 33 is applied to the first pressure receiving surface 41a of the valve body 40, and the valve body 40 further rises. Eventually, the first valve portion 41 rises to a position where the relief port 4b is opened, and a part of the hydraulic oil discharged from the first discharge port 32 and the hydraulic oil discharged from the second discharge port 33 A part is returned to the suction port 31 via the return flow path 16 (second state). As a result, as the rotational speed of the engine E increases, the increasing gradient of the discharge pressure of the pump 1 becomes gentle (after N4 in FIG. 7).

  As described above, the relief valve 4 is configured to be able to switch between the first state and the second state in accordance with the movement of the valve body 40, thereby reducing the wasteful work of the pump 1 and improving the fuel consumption. can do. On the other hand, when the measured temperature Td of the hydraulic oil discharged from the pump 1 is lower than the predetermined temperature T1, the viscosity of the hydraulic oil is increased and the pressure acting on the valve body 40 is increased. The timing for switching from the second state to the first state is accelerated. As a result, as indicated by the dotted line in FIG. 7, the engine speed range in which the useless work of the pump 1 can be reduced becomes narrow.

  Therefore, in the present embodiment, as described above, the electromagnetic valve 5 is disposed in the branch flow path 15 connected to the pressure chamber 45 provided in the accommodation space of the spring 44 of the relief valve 4. As a result, the solenoid valve 5 is opened and hydraulic oil is supplied to the pressure chamber 45 so as to maintain the position of the valve body 40 in the second state shown in FIG. 3, and the second state is switched to the first state. Timing can be delayed. In particular, in the present embodiment, the pressure in the pressure chamber 45 is applied to the fourth pressure receiving surface 42c of the cylindrical portion 42b that holds the spring 44, and the pressure in the pressure chamber 45 is set in a state in which the spring 44 is normally set. If changed, the position of the valve body 40 can be set, so the control method is simple. When the solenoid valve 5 is opened, the control unit 9 adjusts the energization amount to the solenoid valve 5 according to the measured pressure Pd of the pressure sensor P, and executes control to hold the position of the valve body 40 in the second state. . That is, in the present embodiment, the supply amount of hydraulic oil to the pressure chamber 45 is adjusted by controlling the energization amount to the electromagnetic valve 5 in the supply mode for supplying the hydraulic oil to the pressure chamber 45. .

  Further, the control unit 9 operates to circulate to the supplied part of the engine E based on the measured pressure Pd of the pressure sensor P, the measured temperature Td of the temperature sensor T, the actual rotation speed of the engine E, the load information of the engine E, etc. The oil target pressure Pc is calculated. For this calculation, for example, a map or a predetermined definition function that outputs the target hydraulic pressure using the measured temperature Td of the temperature sensor T and the actual rotational speed of the engine E as input variables is used. In place of the actual engine speed, the load information of the engine E or the measured pressure Pd of the pressure sensor P may be used as an input variable, or two or more input variables may be combined.

[Control method]
Hereinafter, an example of the control method according to the present embodiment will be described with reference to FIGS.

  First, it is determined whether or not the measured temperature Td of the temperature sensor T is equal to or lower than a predetermined temperature T1 (# 70). When the hydraulic oil is hot (# 70 No determination), the solenoid valve 5 is not energized, and the normal mode in which the hydraulic oil is not supplied to the pressure chamber 45 is set (# 71). This is because when the hydraulic oil is hot, the pressure acting on the valve body 40 is relatively small, so that the timing at which the position of the valve body 40 shifts from the second state to the first state is not accelerated. This is because the useless work amount can be appropriately reduced. The predetermined temperature T1 may be changed according to the load information of the engine E. For example, when the load on the engine E is large, it is necessary to secure a large amount of hydraulic oil to be circulated to the supplied part. Therefore, the engine in which the discharge pressure of the pump 1 is set to a high pressure by setting the predetermined temperature T1 lower. An operation for expanding the rotation speed region of E is executed.

  On the other hand, when the hydraulic oil is at a low temperature (# 70 Yes determination), the controller 9 calculates the target pressure Pc (# 72). Next, it is determined whether or not the measured pressure Pd is greater than the target pressure Pc (# 73). When the measured pressure Pd is equal to or lower than the target pressure Pc (# 73 No determination), since there is not enough hydraulic oil to circulate to the supplied part of the engine E, the solenoid valve 5 is energized to open and the pressure chamber 45 is operated. Oil is supplied (# 74). As a result, the pressure from the pressure chamber 45 assists the urging force of the spring 44 and moves the valve body 40 in the downward direction B1. At this time, it is preferable to set the energization amount to the solenoid valve 5 to the maximum value. Thus, the valve body 40 is moved to the lower limit position, and the discharge pressure of the pump 1 can be set to a high pressure until the rotational speed reaches N1, for example, as shown by the solid line in FIG. For this reason, the inconvenience that the position of the valve body 40 is quickly shifted from the first state to the second state, and the hydraulic oil to be circulated to the supplied portion of the engine E is solved.

  After the hydraulic oil is supplied to the pressure chamber 45, the measured pressure Pd becomes larger than the target pressure Pc (# 73 Yes determination), and when the hydraulic oil discharged from the second discharge port 33 is not in the second state for relief (# 75 No. (Decision), the energization of the solenoid valve 5 is turned off and the hydraulic oil in the pressure chamber 45 is discharged (# 76). When the measured pressure Pd is equal to or lower than the target pressure Pc, the control for supplying the hydraulic oil to the pressure chamber 45 by energizing the solenoid valve 5 is performed regardless of the measured temperature Td of the hydraulic oil. good. That is, by executing this control, the inconvenience that the hydraulic fluid circulating to the engine E is insufficient even when the hydraulic fluid is high temperature and low in viscosity is solved.

  If the measured pressure Pd is greater than the target pressure Pc (# 73 Yes determination), it is determined whether the engine E is at a rotational speed at which hydraulic oil is relieved from the second discharge port 33 (# 75). Specifically, at the time of acceleration of the vehicle shown in FIG. 7, it is determined whether or not the engine speed range is in a range from N2 to N3. When the vehicle shown in FIG. It is determined whether the number area is in the range of N4 to N2.

  If the rotational speed of engine E is not within the predetermined range (# 75 No determination), the process returns to the beginning and is repeated until the rotational speed of engine E falls within the predetermined range (# 70 to # 76).

  On the other hand, when the rotational speed of the engine E is in a predetermined range (# 75 Yes determination), the solenoid valve 5 is energized with a predetermined current value according to the measured pressure Pd (# 77). This is because the movement amount of the spool 53 is balanced so that the measured pressure Pd of the hydraulic oil acting on the valve body 40 and the total value of the biasing force of the spring 44 and the pressure of the hydraulic oil supplied to the pressure chamber 45 are balanced. That is, control is performed in which the valve opening amount of the electromagnetic valve 5 is determined and fed back as a current value to be supplied to the electromagnetic valve 5. As a result, the position of the valve body 40 is maintained in the second state (# 78), and the hydraulic oil discharged from the second discharge port 33 is relieved.

  Accordingly, during acceleration of the vehicle shown in FIG. 7, the relief valve 4 is not switched to the first state while the engine speed range is from N2 to N3. Therefore, when the electromagnetic valve 5 indicated by the solid line is provided, the wasteful work of the pump 1 can be further reduced as compared with the case where the electromagnetic valve 5 indicated by the dotted line is not provided.

  On the other hand, at the time of deceleration of the vehicle shown in FIG. 8, hydraulic oil is supplied to the pressure chamber 45 so that the relief valve 4 is in the second state when the rotational speed region of the engine E becomes N4. In particular, when the vehicle is decelerated, if the solenoid valve 5 indicated by the dotted line in FIG. 8 is not provided, a large discharge pressure that acts on the valve body 40 remains, so that the valve body 40 is switched to the second state. Takes time (hysteresis characteristics). As a result, the effect of reducing the work amount of the pump 1 is less than in the case indicated by the dotted line in FIG. However, when the electromagnetic valve 5 is forcibly opened to supply the hydraulic oil to the pressure chamber 45 as in this embodiment, the timing for switching to the second state can be freely set. For this reason, as shown with the continuous line of FIG. 8, the useless work of the pump 1 can be reduced further.

  Returning to the control flow of FIG. 6, it is determined whether or not the rotation speed is shifted to the first state in which the hydraulic oil discharged from the first discharge port 32 and the hydraulic oil discharged from the second discharge port 33 are merged. (# 79). Specifically, at the time of acceleration of the vehicle shown in FIG. 7, it is determined whether or not the number of revolutions of engine E exceeds N3. At the time of deceleration of the vehicle shown in FIG. It is determined whether it has fallen below.

  When the rotational speed of engine E is not the rotational speed to be shifted to the first state (# 79 No determination), control for maintaining the rotational speed of engine E in the second state is executed (# 77 to # 78). On the other hand, when the rotational speed of the engine E is the rotational speed to shift to the first state (# 79 Yes determination), the energization to the solenoid valve 5 is turned off, and the hydraulic oil in the pressure chamber 45 is electromagnetically coupled to the drain port 4c. It is discharged through the drain port 54c of the valve 5 (# 80).

  As a result, at the time of acceleration of the vehicle shown in FIG. 7, the valve body 40 moves in the ascending direction B2, shifts to the first state shown in FIG. 4, and the discharge pressure of the pump 1 suddenly rises to a high pressure setting. Return (N3 to N4 in FIG. 7). On the other hand, at the time of deceleration of the vehicle shown in FIG. 8, the discharge pressure from the first discharge port 32 acting on the valve body 40 decreases due to the decrease in the rotation speed of the engine E, but the valve body 40 is moved in the direction B1. Since the hydraulic oil in the pressure chamber 45 to be lowered is drained, it does not immediately shift to the first state, and the discharge pressure of the pump 1 falls with a gentle gradient (N2 to N1 in FIG. 8).

[Another embodiment]
Hereinafter, another embodiment will be described. Since the basic configuration is the same as that of the above-described embodiment, only different configurations will be described with reference to the drawings. In addition, in order to make an understanding of drawing easy, it demonstrates using the same member name and code | symbol as embodiment mentioned above.

  The pressure adjustment system X of another embodiment includes a holding body 46 that holds an end portion of the spring 44 opposite to the valve body 40 in the accommodation space of the spring 44 of the relief valve 4. A pressure chamber 45 is provided on the opposite side of the spring 44. The holding body 46 includes a pressure receiving surface 46a that receives the pressure of the hydraulic oil supplied to the pressure chamber 45, and a protrusion 46b that extends from the pressure receiving surface 46a. The upper limit position of the holding body 46 is set by the protrusion 46b. That is, in another embodiment, the holding body 46 that has received the pressure from the pressure chamber 45 moves in the direction B1 in which the spring 44 is compressed, thereby increasing the urging force of the spring 44. As a result, the moving speed of the valve body 40 can be reduced, and the timing for switching from the second state to the first state can be delayed.

  In the above-described embodiment, the urging force is applied while the spring 44 is extended by supplying the hydraulic oil to the pressure chamber 45, but in another embodiment, the spring 44 is shortened by supplying the hydraulic oil to the pressure chamber 45. This increases the biasing force. That is, in another embodiment, since it is not necessary to ensure the spring characteristics over a long stroke, the spring 44 can be made compact.

[Other Embodiments]
(1) In the above-described embodiment, the amount of hydraulic oil supplied to the pressure chamber 45 is adjusted by controlling the amount of current supplied to the electromagnetic valve 5. It is good also as an ON / OFF control valve which selectively switches between the supply mode which supplies oil, and the discharge mode which discharges hydraulic oil from the pressure chamber 45. Even in this case, since the valve body 40 can be moved in the downward direction B2, the hydraulic oil discharged from the second discharge port 33 is discharged from the second state in which the hydraulic oil is relieved through the relief port 4b. The timing for switching to the first state where the hydraulic oil discharged from the port 32 is merged can be delayed. As a result, an effect of reducing the work amount of the pump 1 can be expected. In this case, since the step of controlling the energization amount to the electromagnetic valve 5 according to the measured pressure Pd of the pressure sensor P can be omitted, the calculation amount of the control unit 9 can be reduced.
(2) In the above-described embodiment, the discharge port is divided into two parts, but may be formed into three or more parts. Moreover, you may comprise the valve part of the valve body 40 by 1 or 3 or more.
(3) In the above-described embodiment, the pump 1 is a trochoid pump, but any pump such as a vane pump may be used.
(4) In the above-described embodiment, the drain port 4 c of the pressure chamber 45 and the drain port 54 c of the electromagnetic valve 5 are communicated with the oil pan 7, but may be communicated with the suction port 31 of the pump 1. Further, the return flow path 16 communicated with the suction port 31 may be communicated with the oil pan 7 and is not particularly limited.

  INDUSTRIAL APPLICABILITY The present invention can be used for a pressure adjustment system that adjusts the discharge pressure of an oil pump that circulates hydraulic oil to a supply portion of an engine.

1 Pump (oil pump)
14 Supply flow path 15 Branch flow path 16 Return flow path 31 Suction port 32 First discharge port 33 Second discharge port 4 Relief valve (control valve)
4c Drain port 40 Valve body 44 Spring 45 Pressure chamber 5 Solenoid valve

Claims (4)

An oil pump having a suction port to which hydraulic oil is supplied, a first discharge port and a second discharge port from which hydraulic oil is discharged;
A supply flow path for supplying hydraulic oil discharged from the first discharge port to the supply portion;
A return flow path for returning the hydraulic oil discharged from the second discharge port to the suction port or the oil pan;
A valve body that receives the pressure of hydraulic oil flowing through the feed passage, a spring that urges the valve body in a direction opposite to the pressure, and a pressure chamber that is provided in a housing space of the spring, A first state in which the hydraulic oil discharged from the second discharge port merges with the hydraulic oil discharged from the first discharge port as the valve body moves, and an operation discharged from the second discharge port A control valve switchable to a second state for returning oil to the return flow path;
A pressure regulating system comprising: an electromagnetic valve that is branched from the supply flow path and is arranged in a branch flow path that is connected to the pressure chamber, and that controls the supply of hydraulic oil to the pressure chamber.   The pressure adjustment system according to claim 1, wherein the electromagnetic valve selectively switches between a supply mode for supplying hydraulic oil to the pressure chamber and a shut-off mode for blocking supply of hydraulic oil to the pressure chamber. The solenoid valve includes a supply mode for supplying hydraulic oil to the pressure chamber, and a cutoff mode for blocking supply of hydraulic oil to the pressure chamber,
The pressure adjustment system according to claim 1, wherein the supply amount of hydraulic oil to the pressure chamber is adjusted by controlling an energization amount to the electromagnetic valve during the supply mode. The pressure chamber is formed with a drain port that discharges the working oil flowing inside to the outside.
The pressure adjustment system according to any one of claims 1 to 3, wherein an opening area of the drain port is set smaller than a cross-sectional area of the branch channel.

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