Patent Application
20190219053
The present invention relates to a variable capacity pump.
Conventionally, variable capacity pumps are known.
PTL 1: Japanese Patent Laid-Open No. S59-70891
Conventional variable capacity pumps have room for improvement in terms of ease of control.
A variable capacity pump according to one embodiment of the present invention preferably includes a control portion which varies the cross-sectional area of the flow passage through which working oil in a control chamber is drained while making a discharge portion and a control chamber communicate with each other.
Accordingly, ease of control can be improved.
Hereinafter, embodiments for carrying out the present invention are described with reference to drawings.
First, the configuration is described. A variable capacity pump (hereinafter referred to as “pump”) 2 of this embodiment is an oil pump used in a working oil supply system 1 of an internal combustion engine (engine) of an automobile. The pump 2 is disposed at a front end portion or the like of a cylinder block of the engine. The pump 2 supplies oil (working oil), which is a fluid having functions, such as lubrication, to respective slide portions of the engine, and to a variable valve device (valve timing control device and the like) which variably controls operation characteristics of a valve of the engine. As shown in
As shown in
The drive shaft 21 is rotatably supported on the housing. The drive shaft 21 is coupled to a crankshaft by way of a chain, a gear or the like. The rotor 22 is fixed to the drive shaft 21 in the circumferential direction. The rotor 22 has a columnar shape. A surface of the rotor 22 on one side in the axial direction has a recessed portion 221. A plurality of (seven) slits 222 extending in the radial direction are formed in the rotor 22. Back pressure chambers 223 are disposed on the inner side of the slits 222 in the radial direction. The outer peripheral surface 220 of the rotor 22 has projecting portions 224 which protrude outward in the radial direction. The slits 222 are open on the projecting portions 224. The vanes 23 are accommodated in the slits 222. An annular member 230 is provided in the recessed portion 221. The outer peripheral surface of the member 230 opposes the proximal ends of the respective vanes 23. An inner peripheral surface 240 of the cam ring 24 has a cylindrical shape. The outer periphery of the cam ring 24 has four protrusions 241 to 244 which protrude outward in the radial direction. The first sealing member 261 is mounted on the first protrusion 241. The second sealing member 262 is mounted on the second protrusion 242. The pin 27 is fitted in the third protrusion 243. As viewed in the axial direction of the cam ring 24, the first protrusion 241 and the second protrusion 242 are disposed on sides opposite to each other with respect to a straight line passing through the axis of the pin 27 and a center 24P of the inner peripheral surface 240 of the cam ring. One end of the spring 25 is mounted on the fourth protrusion 244.
On the inside of the pump accommodating chamber 200, a first control chamber 291, a first control chamber 292, and a spring accommodating chamber 293 are present between the housing and the cam ring 24. The first control chamber 291 is formed of a space defined between a portion of an outer peripheral surface 245 of the cam ring 24 ranging from the first protrusion 241 (first sealing member 261) to the third protrusion 243 (pin 27), and the inner peripheral surface of the housing (pump accommodating chamber 200). The first control chamber 291 is sealed by the first sealing member 261 and the pin 27. A first region 246 defined between the first sealing member 261 and the pin 27 on the outer peripheral surface 245 of the cam ring faces the first control chamber 291. A second control chamber 292 is formed of a space defined between a portion of the outer peripheral surface 245 of the cam ring ranging from the second protrusion 242 (second sealing member 262) to the third protrusion 243 (pin 27), and the inner peripheral surface of the housing (pump accommodating chamber 200). The second control chamber 292 is sealed by the second sealing member 262 and the pin 27. A second region 247 defined between the second sealing member 262 and the pin 27 on the outer peripheral surface 245 of the cam ring faces the second control chamber 292. The area of the second region 247 (angle subtended by the second region 247 in the circumferential direction of the cam ring 24) is slightly larger than the area of the first region 246 (angle subtended by the first region 246 in the circumferential direction of the cam ring 24). The width in the radial direction of a portion of the cam ring 24 which corresponds to the second region 247 (the end surface in the axial direction of the cam ring 24, the end surface being formed so as to continue to the second region 247, and opposing the bottom surface of the pump accommodating chamber 200) is larger than the width in the radial direction of a portion of the cam ring 24 which corresponds to the first region 246 (the end surface in the axial direction of the cam ring 24, the end surface being formed so as to continue to the first region 246, and opposing the bottom surface of the pump accommodating chamber 200) in average at least in a region which is disposed adjacent to the discharge port 204 in the radial direction. The spring accommodating chamber 293 is formed of a space defined between a portion of the outer peripheral surface 245 of the cam ring ranging from the first protrusion 241 (first sealing member 261) to the second protrusion 242 (second sealing member 262) via the fourth protrusion 244, and the inner peripheral surface of the housing (pump accommodating chamber 200).
The spring 25 is a compression coil spring. One end of the spring 25 is brought into contact with the surface of the fourth protrusion 244 on one side in the circumferential direction of the cam ring 24. The surface of the fourth protrusion 244 on the other side in the circumferential direction of the cam ring 24 opposes the inner peripheral surface of the pump accommodating chamber 200 (spring accommodating chamber 293), and is capable of coming into contact with this inner peripheral surface. The other end of the spring 25 is mounted on the inner peripheral surface of the pump accommodating chamber 200 (spring accommodating chamber 293). The spring 25 is in a compressed state. The spring 25 has a predetermined set load in an initial state, and always biases the fourth protrusion 244 to the other side in the circumferential direction.
The control mechanism 3 includes the control passage 43 and a control valve 7. As shown in
As shown in
The spool 81 is a valve element (valve) provided in the second feedback passage 432. The spool 81 is disposed in the cylinder 80 (accommodated in the cylinder 80), and is reciprocable in the axial direction of the cylinder 80 along the inner peripheral surface 800 of the cylinder. The spool 81 includes a first land portion 811, a second land portion 812, and a connecting portion 813. The first land portion 811 is disposed at the end of the spool 81 on one side in the axial direction. The second land portion 812 is disposed at the end of the spool 81 on the other side in the axial direction. The connecting portion 813 is disposed between the first land portion 811 and the second land portion 812, and connects both land portions 811, 812 with each other. The diameter of the first land portion 811 and the diameter of the second land portion 812 are equal to each other. The diameter of both land portions 811, 812 is slightly smaller than the diameter of the inner peripheral surface 800 of the cylinder. The connecting portion 813 is formed of a thin shaft portion. The diameter of the connecting portion 813 is smaller than the diameter of both land portions 811, 812. The respective land portions 811, 812 is in slide contact with the inner peripheral surface 800 of the cylinder.
A space 807 is defined between the first land portion 811 and the second land portion 812 as a liquid chamber in the inside of the cylinder 80. A space 808 is defined between the second land portion 812 and the bottom portion 802. The space 807 is defined by the inner peripheral surface 800 of the cylinder, the outer peripheral surface of the connecting portion 813, the surface of the first land portion 811 on the other side in the axial direction, and the surface of the second land portion 812 on one side in the axial direction. The space 807 has a cylindrical shape (annular shape). The supply port 803 is open to the space 807 in the initial state, and the communication port 804 is always open to the space 807. The drainage port 805 may be open to the space 807. On the inner peripheral side of the cylinder 80, the space 808 is defined between the surface of the second land portion 812 on the other side in the axial direction and the bottom portion 802. The drainage port 805 is slightly open to the space 808 in the initial state. The spring 82 is formed of a compression coil spring, and is disposed in the space 808. The space 808 functions as a spring chamber which accommodates the spring 82. One end side of the spring 82 is fitted on the outer peripheral side of a projection portion which projects from the second land portion 812 of the spool 81, and one end of the spring 82 is in contact with the end surface of the second land portion 812 on the other side. The other end of the spring 82 is in contact with the bottom portion 802. The spring 82 is in a compressed state. The spring 82 has a predetermined set load in the initial state, and always biases the spool 81 to one side in the axial direction. This spring force is defined as fs.
The solenoid portion 9 is joined to one side of the valve portion 8 in the axial direction, thus closing the opening of the cylinder 80 on one side in the axial direction. The solenoid portion 9 is an electromagnet which receives a supply of an electric current through the connector 92. The solenoid and the plunger are accommodated in the casing 90. The solenoid (coil) generates an electromagnetic force when energized. The plunger (armature) is made of a magnetic material, is disposed on the inner peripheral side of the solenoid, and is movable in the axial direction. The plunger is biased in the axial direction by an electromagnetic force generated by the solenoid. The first land portion 811 of the spool 81 is integrally joined to the plunger. The above-mentioned electromagnetic force biases the first land portion 811 (spool 81) to the other side in the axial direction. This electromagnetic force (thrust of the solenoid for propelling the spool 81) is assumed as “fm.” The solenoid can continuously change the magnitude of an electromagnetic force fm according to the value of an electric current supplied. The solenoid portion 9 is subjected to a PWM control, and the current value of the solenoid is given by a duty ratio D. An electromagnetic force fin varies according to duty ratio D (the current value of the solenoid). When a duty ratio D is less than a predetermined value D1 (dead zone), an electromagnetic force fm assumes zero, which is the minimum value (the electromagnetic force is not generated), regardless of the magnitude of the duty ratio D. When a duty ratio D is equal to or more than the predetermined value D1 and less than a predetermined value D2, an electromagnetic force fm varies according to the duty ratio D. With a larger duty ratio D, the electromagnetic force fm increases more. When a duty ratio D is equal to or more than the predetermined value D2, an electromagnetic force fin assumes the maximum value fmax regardless of the magnitude of the duty ratio D.
The pressure sensor 51 detects (measures) the pressure of working oil discharged through the discharge opening 203 of the pump 2 to the discharge passage 41. In other words, the pressure sensor 51 detects (measures) the pressure in the main gallery 42 (main gallery hydraulic pressure P). The rotational speed sensor 52 detects (measures) the rotational speed Ne of the engine (crankshaft).
The engine control unit (hereinafter, ECU) 6 controls the opening/closing of the control valve 7 (that is, the discharge amount of the pump 2) based on inputted information and an incorporated program. With such control, the pressure and flow rate of working oil to be supplied to the engine are controlled. The ECU 6 includes a reception portion, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a drive circuit. The ECU 6 includes, as a main component, a microcomputer where these components are connected with each other through bidirectional common buses. The reception portion receives detected values of the pressure sensor 51 and the rotational speed sensor 52, and other information about engine operation conditions (oil temperature, water temperature, engine load and the like). The ROM is a memory portion which stores control programs, map data and the like. The CPU is an arithmetic operation portion which performs an arithmetic operation using the information inputted from the reception portion based on a control program which is read out. The CPU performs arithmetic operations for values, such as an electric current to be supplied to the control valve 7 (solenoid portion 9). The CPU outputs a control signal which corresponds to the result of the arithmetic operation to the drive circuit. The drive circuit controls an electric current to be supplied to the solenoid such that the drive circuit supplies electric power to the solenoid in response to the control signal outputted from the CPU. The drive circuit is a PWM control circuit, and causes the pulse width (duty ratio D) of a signal for driving the solenoid to be varied in response to the control signal.
During the operation of the engine, the control program is performed so that the control valve 7 (pump 2) is controlled. The ECU 6 causes a value (duty ratio D) of an electric current to be supplied to the solenoid to be varied such that the difference between a main gallery hydraulic pressure P and a predetermined required value P* falls within a predetermined range at any engine speed Ne within a predetermined range of rotational speed of the engine (Ne≥Ne1). Ne1 is a rotational speed which is set in advance. The required value P* is a hydraulic pressure, such as a hydraulic pressure required for operating the variable valve device, a hydraulic pressure required by an oil jet for cooling an engine piston, or a hydraulic pressure required for lubricating a bearing of the crankshaft. The required value P* is set in advance as an ideal value which corresponds to an engine operation condition, such as an engine speed Ne. The ROM of the ECU 6 stores, in the form of a map, required values P* for respective engine speeds Ne (according to the engine operation conditions). The map may set a discharge pressure, an oil temperature, a water temperature, an engine load and the like as parameters, for example. The ECU 6 causes a duty ratio D to be varied according to an engine speed Ne based on the map. The ECU 6 detects a main gallery hydraulic pressure P, and performs feedback control so as to cause the main gallery hydraulic pressure P to approximate a required value P*. The ECU 6 causes a duty ratio D to be varied such that the difference between the detected value and the required value P* for the main gallery hydraulic pressure P falls within a predetermined range. When an engine speed Ne is less than Ne1, the ECU 6 sets a duty ratio D to zero. When an engine speed Ne detected (measured) by a rotational speed sensor 52 is equal to or more than Ne1, the ECU 6 calculates the difference ΔP (=P*−P) between a hydraulic pressure P detected (measured) by a pressure sensor 51 and a required value P* at the above-mentioned (any) rotational speed Ne detected. When the magnitude of the difference ΔP is larger than a value ΔPset set in advance, a duty ratio D is caused to be varied such that the magnitude of the difference ΔP is reduced until the magnitude of the difference ΔP becomes equal to or less than the value ΔPset. When the magnitude of the difference ΔP is equal to or less than the value ΔPset, a duty ratio D is maintained (at a value immediately before a value at which the magnitude of the difference ΔP becomes equal to or less than the value ΔPset).
Next, the manner of operation is described. The cam ring 24 accommodates the rotor 22 and the plurality of vanes 23 so that a plurality of pump chambers (working chambers) 28 are defined. The rotor 22 and the plurality of vanes 23 function as elements (pump structures) which constitute the pump 2. Each working chamber 28 is formed (defined) by the outer peripheral surface 220 of the rotor 22, two vanes 23 disposed adjacent to each other, the inner peripheral surface 240 of the cam ring, the bottom surface of the pump accommodating chamber 200, and the side surface of the cover. The volume of each of the working chambers 28 is variable with the rotation. The volume of each working chamber 28 increases and decreases with the rotation and hence, the plurality of working chambers 28 function as a pump. Within a range which overlaps with the intake port 202 (intake region), the volume of the working chamber 28 increases according to the rotation, and the working chamber 28 takes in working oil through the intake port 202. Within a range which overlaps with the discharge port 204 (discharge region), the volume of the working chamber 28 decreases, and the working chamber 28 discharges working oil to the discharge port 204. The theoretical discharge amount (a discharge amount per one rotation), that is capacity, of the pump 2 is determined by the difference between the maximum volume and the minimum volume of the working chamber 28. The rotation of the crankshaft is transmitted to the drive shaft 21 of the pump 2 by way of the chain and the gear. The drive shaft 21 rotationally drives the rotor 22. The rotor 22 rotates in the counterclockwise direction in
The amount of variation in the volume of the working chamber 28 (the difference between the maximum volume and the minimum volume) is variable. The cam ring 24 is a member which is movable (movable member) in the pump accommodating chamber 200, and the cam ring 24 can perform a rotational oscillation about the pin 27. The pin 27 functions as a pivot portion (fulcrum) disposed in the pump accommodating chamber 200. The cam ring 24 performs a rotational oscillation so that the difference (amount of eccentricity Δ) between the axis (center of rotation) 22P of the rotor 22 and the axis (center) 24P of the inner peripheral surface 240 of the cam ring varies. Varying the amount of eccentricity Δ varies the amount of increase or decrease in volume (amount of variation in volume) of each of the plurality of working chambers 28 at the time of rotating the rotor 22 and the plurality of vanes 23. That is, the pump 2 is a variable capacity pump. Accordingly, increasing the amount of eccentricity Δ allows capacity to be increased, and reducing the amount of eccentricity Δ allows capacity to be decreased. Further, the volume of the first control chamber 291 and the volume of the second control chamber 292 can be varied with the movement of the cam ring 24.
The cam ring 24 is biased by the spring 25 to one side (to the side where the amount of increase or decrease in volume of each of the plurality of working chambers 28 increases, and the amount of eccentricity Δ increases) in the rotational direction about the pin 27. This spring force is defined as “Fs.” The cam ring 24 receives the pressure of working oil in the first control chamber 291. The first region 246 of the outer peripheral surface 245 of the cam ring functions as a pressure receiving surface which receives a pressure in the first control chamber 291. The cam ring 24 is biased to the other side (to the side where the amount of eccentricity Δ decreases) in the rotational direction about the pin 27 by the above-mentioned hydraulic pressure. A force generated by this hydraulic pressure (hydraulic pressure force) is defined as “Fp1.” The volume of the first control chamber 291 increases with the movement of the cam ring 24 to the other side (the direction opposing the biasing force Fs of the spring 25) in the above-mentioned rotational direction. The cam ring 24 receives the pressure (control hydraulic pressure) p of working oil in the second control chamber 292. The second region 247 of the outer peripheral surface 245 of the cam ring functions as a pressure receiving surface which receives a control hydraulic pressure p. The cam ring 24 is biased to one side in the above-mentioned rotational direction by the control hydraulic pressure p. A force generated by the control hydraulic pressure p (hydraulic pressure force) is defined as “Fp2.” The volume of the second control chamber 292 increases with the movement of the cam ring 24 to one side (the same direction as the biasing force Fs) in the above-mentioned rotational direction. The position of the cam ring 24 in the rotational direction (the amount of eccentricity Δ, that is, capacity) is mainly determined by hydraulic pressure force Fp1, hydraulic pressure force Fp2, and biasing force Fs. When a hydraulic pressure force Fp1 becomes larger than the sum of hydraulic pressure force Fp2 and biasing force Fs (Fp2+Fs), the cam ring 24 oscillates to the other side in the above-mentioned rotational direction so that the amount of eccentricity Δ (capacity) reduces. When a hydraulic pressure force Fp1 becomes smaller than the sum of hydraulic pressure force Fp2 and biasing force Fs (Fp2+Fs), the cam ring 24 oscillates to one side in the above-mentioned rotational direction so that the amount of eccentricity Δ (capacity) increases.
Working oil discharged through the discharge opening 203 (hydraulic pressure P of the main gallery 42) is introduced into the first control chamber 291 through the first feedback passage 431. Working oil discharged through the discharge opening 203 (main gallery hydraulic pressure P) may be introduced into the second control chamber 292 through the second feedback passage 432 (the supply passage 433, the control valve 7, and the communication passage 434). Working oil in the second control chamber 292 may be drained through the drainage passage 435. The control valve 7 can control an introduction of working oil into the second control chamber 292 and drainage of working oil from the second control chamber 292. The spool 81 moves so as to switch the connection state of the passage. To be more specific, the first land portion 811 causes the opening area of the supply port 803 to be varied, and the second land portion 812 causes the opening area of the drainage port 805 to be varied. The opening of the communication port 804 is not closed by either land portion. The space 807 forms a passage for working oil. Moving the spool 81 switches between establishing and shutting off of the connection between the communication passage 434 and the supply passage 433, or switches between establishing and shutting off of the connection between the communication passage 434 and the drainage passage 435. In performing switching, it is assumed as a basic mode that the communication passage 434 communicates with both of the supply passage 433 and the drainage passage 435. To be more specific, in a state where the first land portion 811 partially closes the opening of the supply port 803 which is open to the space 807, the second land portion 812 causes the drainage port 805 to be open to the space 807. In a state where the second land portion 812 partially closes the opening of the drainage port 805 which is open to the space 807, the first land portion 811 causes the supply port 803 to be open to the space 807. The opening of the communication port 804, which is open to the space 807, is always fully open. In performing switching, it is sufficient to have a state where the supply port 803 and the drainage port 805 are simultaneously open to the space 807 (temporarily at a predetermined position of the spool 81). It is not necessary to have a state where the maximum opening area of the supply port 803, which is open to the space 807, and the maximum opening area of the drainage port 805, which is open to the space 807, are equal to each other. Further, it is not necessary that the position of the spool at which the opening area of the supply port 803, which is open to the space 807, starts to decrease be to the same as the position of the spool at which the drainage port 805 starts to become open to the space 807. It is not also necessary that the position of the spool at which the opening area of the drainage port 805, which is open to the space 807, starts to decrease be to the same as the position of the spool at which the supply port 803 starts to become open to the space 807. These cases are determined by tuning.
The spool 81 switches the connection state of the passage, thus switching between establishing and shutting off of the communication between the discharge opening 203 and the second control chamber 292 (through the communication passage 434 and the supply passage 433) and, switching between establishing and shutting off of the communication between the second control chamber 292 and the oil pan 400 (through the communication passage 434 and the drainage passage 435). As shown in
As shown in
The solenoid portion 9 can move the spool 81 to any position in response to a control signal (duty ratio D). The position of the spool 81 is proportional to a duty ratio D on average. The control valve 7 functions as a proportional control valve. The control valve 7 can continuously change the position of the spool 81, and can also stop the spool 81 at any position. The position of the spool 81 in the axial direction with respect to the cylinder 80 is mainly determined by a spring force fs and an electromagnetic force fm. The solenoid can continuously change an electromagnetic force fm. Changing the magnitude of electromagnetic force fm allows the spool 81 to move, in other words, allows a transition between the above-mentioned states (state transition). When an electromagnetic force fm becomes larger than a spring force fs, the spool 81 moves to the other side in the axial direction, thus realizing a state transition from the first state toward the fourth state. When an electromagnetic force fm becomes smaller than a spring force fs, the spool 81 moves to one side in the axial direction, thus realizing a state transition from the fourth state toward the first state. An electromagnetic force fm varies according to a duty ratio D. The solenoid functions as a proportional electromagnet which can continuously control an electromagnetic force fm according to a duty ratio D (current value). Basically, an electromagnetic force fm increases when a duty ratio D is increased. The position of the spool 81 (land portions 811, 812) is determined according to a duty ratio D. As shown in
The description is made with respect to the operation of the control valve 7 according to the variation in thrust fm of the solenoid (duty ratio D) and the operation of the cam ring 24 which is caused with this operation of the control valve 7. In
When a duty ratio D is equal to or more than the predetermined value Ds and less than the predetermined value De, and a thrust fm is larger than a spring force fs (set load of the spring 82), as shown in
When a duty ratio D further increases in a range where the duty ratio D is less than the predetermined value De, a thrust fm further increases so that, as shown in
As described above, the control valve 7 changes a control hydraulic pressure p and an amount of eccentricity Δ (capacity) by changing the position of the spool 81 according to a duty ratio D. With such a change, the control valve 7 can control a hydraulic pressure P and a discharge flow rate. As shown in
The ECU 6 causes a duty ratio D to be varied according to the stored map such that, within a range where an engine speed Ne is equal to or more than Ne1, the difference ΔP between the detected value and a required value P* for the main gallery hydraulic pressure P falls within a predetermined range. With such a variation, it is possible to realize a characteristic of a hydraulic pressure P with respect to an engine speed Ne as indicated by a bold solid line in
The solenoid can change, according to duty ratio D (the value of an electric current supplied), the magnitude of an electromagnetic force fm which biases the spool 81 in the axial direction. Accordingly, varying duty ratio D according to engine speed Ne allows main gallery hydraulic pressure P and discharge flow rate to be freely varied (controlled). Characteristics of main gallery hydraulic pressure P and discharge flow rate with respect to engine speed Ne can be easily caused to approximate desired characteristics. Accordingly, power loss caused due to unnecessary rise in discharge pressure (increase in flow rate) can be suppressed so that fuel economy can be improved. In the above-mentioned description, characteristic is described to have a stairs-like shape for facilitating understanding of the description. However, in an actual control, numerous number of stairs may be formed, that is, main gallery hydraulic pressure P may be steplessly controlled according to an engine speed Ne, thus approximately continuously controlling the main gallery hydraulic pressure P according to required hydraulic pressure P*. A main gallery hydraulic pressure P is feedback controlled according to a differential pressure ΔP and hence, the control valve 7 and the cam ring 24 are operated such that the characteristic of a discharge pressure P which corresponds to the variation in engine speed Ne approximates a required characteristic. With such feedback control, while the pump 2 is prevented from being affected by leakage (leakage of working oil) or the like caused by a clearance formed between members, the characteristic of a hydraulic pressure P can be accurately controlled. A method for feedback controlling a hydraulic pressure P to a required value P* is not limited to the above-mentioned method, and any method may be adopted. Setting a value ΔPset to a smaller value allows steps of a stairs-like shape to continuously change more finely. A value ΔPset may be set to zero. Hunting in control can be suppressed by setting a value ΔPset to a value other than zero, and by preventing a duty ratio D from being varied when the magnitude of difference ΔP is equal to or less than the value ΔPset.
The control valve 7 can continuously change the position of the spool 81. Accordingly, the control valve 7 can move the spool 81 to any position, thus controlling a control hydraulic pressure p, an amount of eccentricity Δ (capacity), and a main gallery hydraulic pressure P to any values. The control valve 7 can stop the spool 81 at any position. Accordingly, the control valve 7 can fix the spool 81 at any position, thus fixing a control hydraulic pressure p and an amount of eccentricity Δ (capacity) at any values. Therefore, the control valve 7 can realize control to fix a gradient when a hydraulic pressure P rises or drops according to a variation in engine speed Ne.
The control valve 7 includes the solenoid portion 9 which is capable of generating an electromagnetic force fm for biasing the spool 81. Accordingly, the spool 81 can be moved to any position by the solenoid portion 9. The spool 81 is integrally coupled with the plunger of the solenoid portion 9. Therefore, even if a force generated by a hydraulic pressure acts on the spool 81 from one side or the other side in the axial direction, it is possible to prevent the spool 81 from being moved. With such a configuration, a control hydraulic pressure p, an amount of eccentricity Δ, and a hydraulic pressure P are prevented from being easily affected by disturbances and hence, ease of control can be improved. A control hydraulic pressure p, an amount of eccentricity Δ, and a hydraulic pressure P are controlled by opening/closing the port of the control valve 7 and hence, the control is not affected by the spring constant of the spring 25 of the cam ring 24.
The control valve 7 is provided in the second feedback passage 432. With the movement of the spool 81, the control valve 7 varies the cross-sectional area Sd of the flow passage, through which working oil in the second control chamber 292 is drained to the oil pan 400, while making the discharge opening 203 and the second control chamber 292 communicate with each other. By varying the cross-sectional area Sd of the flow passage as described above, the drainage amount of working oil from the space 807 (second control chamber 292) is varied (adjusted). With such variation, a control hydraulic pressure p is varied (controlled), thus controlling the amount of eccentricity Δ (capacity) and a main gallery hydraulic pressure P. In this embodiment, simultaneously with the variation in the cross-sectional area Sd, the discharge opening 203 and the space 807 (second control chamber 292) are made to communicate with each other. Accordingly, the drainage amount of working oil from the second control chamber 292 varies slowly with respect to the movement of the spool 81. Therefore, a control hydraulic pressure p, an amount of eccentricity Δ (capacity), and a main gallery hydraulic pressure P vary slowly with respect to variation in duty ratio D (the movement amount of the spool 81) (the rapid operation of the cam ring 24 is suppressed). As a result, ease of control of a main gallery hydraulic pressure P is improved.
With the movement of the spool 81 to the other side in the axial direction (in the first direction), the control valve 7 increases the cross-sectional area Sd of the flow passage, through which working oil in the second control chamber 292 is drained to the oil pan 400, while decreasing the cross-sectional area Si of the flow passage, through which working oil is introduce from the discharge opening 203 to the second control chamber 292. Accordingly, the discharge opening 203 and the space 807 (second control chamber 292) are made to communicate with each other simultaneously with an increase in the cross-sectional area Sd and hence, a drainage amount from the second control chamber 292 increases slowly with respect to the movement of the spool 81. Accordingly, it is possible to cause the falling gradient of a hydraulic pressure P to slowly decrease with respect to a variation (increase) in duty ratio D. Further, the orifice diameter of the supply port 803 decreases with a decrease in the opening area Si. That is, the supply port 803 functions as a variable orifice. For this reason, it is possible to cause a hydraulic pressure in the space 807 (that is, a control hydraulic pressure p) to drop sufficiently with respect to a hydraulic pressure P in the supply passage 433 without significantly increasing the drainage amount from the space 807. Accordingly, an increase in drainage amount can be suppressed, thus suppressing lowering of efficiency of the pump 2. Further, an opening area Si is decreased in increasing a drainage amount from the second control chamber 292 so that an amount of working oil which can be introduced into the second control chamber 292 decreases. Therefore, it is possible to cause a control hydraulic pressure p to drop sufficiently when desired and hence, a range (lower limit) of a control hydraulic pressure p can be expanded. For this reason, ease of control is improved.
With the movement of the spool 81 to one side in the axial direction (in a second direction), the control valve 7 decreases the cross-sectional area Sd of the flow passage while increasing the cross-sectional area Si of the flow passage. Accordingly, the discharge opening 203 and the space 807 (second control chamber 292) are made to communicate with each other simultaneously with a decrease in the cross-sectional area Sd and hence, a drainage amount from the second control chamber 292 decreases slowly with respect to the movement of the spool 81. Accordingly, it is possible to cause the rising gradient of a hydraulic pressure P to slowly increase with respect to a variation (decrease) in duty ratio D. Further, an opening area Si is increased in decreasing a drainage amount from the second control chamber 292 so that an amount of working oil which can be introduced into the second control chamber 292 increases. Therefore, it is possible to cause a control hydraulic pressure p to sufficiently rise when desired and hence, a range (upper limit) of a control hydraulic pressure p can be expanded. In other words, when the amount of working oil which is discharged from the discharge opening 203 and introduced into the second control chamber 292 increases, a control mechanism 3 decreases the amount of working oil drained from the inside of the second control chamber 292. When the amount of working oil which is discharged from the discharge opening 203 and introduced into the second control chamber 292 decreases, the control mechanism 3 increases the amount of working oil drained from the inside of the second control chamber 292. Accordingly, it becomes possible to vary (control) a control hydraulic pressure p within a wide range from a low pressure to a high pressure. Further, the operation of the cam ring 24 becomes stable so that a discharge pressure P also becomes stable.
To be more specific, the cylinder 80 of the control valve 7 has the supply port 803 as a first port communicating with the discharge opening 203, the communication port 804 as a second port communicating with the second control chamber 292, and the drainage port 805 as a third port communicating with the oil pan 400. These ports 803 to 805 are open on the inner periphery of the cylinder 80. The various ports of the control valve 7 can be formed with a simple configuration described above. It is sufficient for the drainage port 805 to communicate with the low pressure portion. It is not limited to the configuration that the drainage port 805 communicates with the oil pan 400 (atmospheric pressure). For example, the drainage port 805 may communicate with the intake opening 201 side (where an intake negative pressure is generated). The spool 81 of the control valve 7 is movable in the cylinder 80. The spool 81 includes: the first land portion 811 as a first large diameter portion which can vary the area of the above-mentioned opening of the supply port 803; and the second land portion 812 as a second large diameter portion which can vary the area of the above-mentioned opening of the drainage port 805. With such a simple configuration of a spool valve, the valve portion 8 can control a control hydraulic pressure p.
To be more specific, the first land portion 811 and the second land portion 812 are disposed such that the respective ports 803 to 805 can be at least partially open simultaneously on the inner periphery of the spool 81 within a range (space 807) between the first land portion 811 and the second land portion 812. Accordingly, simultaneous with the communication between the supply port 803 (discharge opening 203) and the communication port 804 (second control chamber 292) via the space 807, the communication port 804 (second control chamber 292) and the drainage port 805 (oil pan 400) can be made to communicate with each other. Further, with the movement of the spool 81, the opening area Sd of the drainage port 805 which is open to the space 807 (the cross-sectional area of the flow passage through which working oil in the second control chamber 292 is drained to the oil pan 400) can be varied while the supply port 803 (discharge opening 203) and the communication port 804 (second control chamber 292) are made to communicate with each other. In other words, in a state where a flow of working oil from the supply port 803 to the communication port 804, and a flow of working oil from the communication port 804 to the drainage port 805 are allowed, the first land portion 811 can vary the cross-sectional area of the flow passage between the supply port 803 and the communication port 804. Further, the second land portion 812 can vary the cross-sectional area of the flow passage between the communication port 804 and the drainage port 805. To be more specific, the first land portion 811 can vary the area of the above-mentioned opening of the supply port 803. The second land portion 812 can vary the area of the above-mentioned opening of the drainage port 805. When the first land portion 811 varies the area of the above-mentioned opening of the supply port 803, the second land portion 812 varies the area of the above-mentioned opening of the drainage port 805. With the movement of the spool 81 to one side in the axial direction, the opening area Sd decreases while the opening area Si of the supply port 803 which is open to the space 807 (the cross-sectional area of the flow passage through which working oil is introduced from the discharge opening 203 to the second control chamber 292) increases. With the movement of the spool 81 to the other side in the axial direction, the opening area Sd increases while the opening area Si decreases.
The spool 81 includes the first land portion 811, the second land portion 812, and the connecting portion 813. The connecting portion 813 connects the first land portion 811 and the second land portion 812 with each other. The first land portion 811 is disposed on the supply port 803 side, and is biased to one side in the axial direction by the solenoid portion 9. The second land portion 812 is disposed on the drainage port 805 side, and is biased to the other side in the axial direction by the spring 82. As described above, the spring 82 and the solenoid portion 9 differ from each other in the direction that the member biases the spool 81 and hence, the electromagnetic force fm and the spring force fs act in opposite directions. Accordingly, the solenoid portion 9 can favorably control the spool 81. Further, the spring 82 functions as a return spring for the spool 81 (the plunger of the solenoid portion 9). Also in the case where there is a malfunction in the solenoid portion 9, the spool 81 is biased to the other side in the axial direction (toward the initial position) by the spring 82 so that it is possible to set the amount of eccentricity Δ to the maximum. Therefore, it is possible to cause a discharge pressure P to rise with the maximum gradient according to an increase in the engine speed Ne.
The area of the first region 246 of the outer peripheral surface 245 of the cam ring which faces the first control chamber 291 may be set equal to the area of the second region 246 of the outer peripheral surface 245 of the cam ring which faces the second control chamber 292. Alternatively, the area of the second region 247 may be set smaller than the area of the first region 246. In this embodiment, the area of the second region 247 (pressure receiving area) is larger than the area of the first region 246 (pressure receiving area). Accordingly, during the operation of the pump 2 at a high speed, a stable hydraulic pressure P can be supplied. That is, when an engine speed Ne (pump rotational speed) rises, air bubbles may be generated in working oil. When these air bubbles are collapsed in the working chamber 28 within the discharge region, there is a possibility that a balance of pressure which acts on the cam ring 24 is disturbed so that the behavior of the cam ring 24 becomes unstable, thus causing discharge pressure P to drop. However, even when the pressure in the first control chamber 291 and the pressure in the second control chamber 292 are equal to each other, hydraulic pressure force Fp2 is larger than hydraulic pressure force Fp1. Accordingly, even if a balance of a pressure which acts on the cam ring 24 from the working chamber 28 is disturbed, the cam ring 24 is biased in the direction that an amount of eccentricity Δ increases, thus suppressing that the behavior of the cam ring 24 becomes unstable. Therefore, it is possible to suppress dropping of control hydraulic pressure P so that a stable control hydraulic pressure P can be supplied. In other words, it becomes possible to discharge working oil of high pressure.
The volume of the first control chamber 291 increases with the movement of the cam ring 24 in the direction opposing the biasing force Fs of the spring 25. That is, hydraulic pressure force Fp1 acts in the direction opposite to the direction of biasing force Fs. The volume of the second control chamber 292 increases with the movement of the cam ring 24 in the same direction as biasing force Fs. That is, hydraulic pressure force Fp2 acts in the same direction as biasing force Fs, thus assisting the biasing force Fs. The operation of the cam ring 24 is decided by the magnitude relationship between hydraulic pressure force Fp1 and the sum of hydraulic pressure force Fp2 and biasing force Fs (Fp2+Fs). Accordingly, only a small biasing force Fs is required for causing the cam ring 24 to be operated in the direction that the amount of eccentricity Δ increases. The load of the spring 25 can be reduced. Accordingly, only a small hydraulic pressure force Fp1 is required for causing the cam ring 24 to be operated in the direction that the amount of eccentricity Δ decreases. That is, it is possible to lower a discharge pressure when the cam ring 24 is operated in the direction that the amount of eccentricity Δ decreases. In other words, discharge of a low pressure working oil can be realized. The cam ring 24 can be oscillated about a fulcrum disposed in the pump accommodating chamber 200. Accordingly, a range where the cam ring 24 is operated can be made compact, thus realizing the reduction in size of the pump 2.
Lowering a pressure in the second control chamber 292 increases the difference between the pressure in the second control chamber 292 and the pressure at the discharge port 204. Accordingly, there is a possibility of increase in the amount of working oil to be leaked through a gap formed between the side surface of the cam ring 24 in the axial direction and the bottom surface of the pump accommodating chamber 200. However, the width in the radial direction of the second region 247 of the cam ring 24 is larger than the width in the radial direction of the first region 246. Accordingly, sealing property is improved more on the second control chamber 292 side than on the first control chamber 291 side and hence, the above-mentioned leakage can be suppressed. A discharge pressure is always introduced into the first control chamber 291 so that the difference between the pressure in the first control chamber 291 and the pressure at the discharge port 204 is small. Accordingly, sealing property is improved (the width in the radial direction is increased) only on the second control chamber 292 side and hence, unnecessary increase in weight is suppressed.
First, the configuration is described. As shown in
One end side of a spring 82C is fitted on the outer peripheral side of a projection portion which projects from the first land portion 814 of the spool 81C, and one end of the spring 82C is in contact with the end surface of the first land portion 814 on one side. The other end of the spring 82C is in contact with a bottom portion 802. A spring force fs of the spring 82C biases the first land portion 814 (spool 81C) to the other side in the axial direction. A solenoid portion 9 is joined to the other side of a valve portion 8 in the axial direction, thus closing the opening of the cylinder 80C on the other side in the axial direction. The second land portion 815 of the spool 81C is integrally joined to a plunger. The electromagnetic force fin of the solenoid portion 9 biases the second land portion 815 (the spool 81C and the first land portion 814) to one side in the axial direction. Other configurations are to the same as those in the first embodiment and hence, corresponding constitutional elements are given the same reference numerals, and the repeated description of such constitutional elements is omitted.
Next, the manner of operation is described. The first land portion 814 can vary the opening area of the communication port 804C. When the edge of the first land portion 814 on one side in the axial direction is positioned on the other side in the axial direction of the edge of the communication port 804C on one side in the axial direction, the communication port 804C is at least partially open to the space 808C. The above-mentioned opening of the supply port 803 communicates with the above-mentioned opening of the communication port 804C via the space 808C. The space 808C forms a passage for working oil. When the edge of the first land portion 814 on the other side in the axial direction is positioned on one side in the axial direction of the edge of the communication port 804C on the other side in the axial direction, the communication port 804C is at least partially open to the space 807C. The above-mentioned opening of the drainage port 805 communicates with the above-mentioned opening of the communication port 804C via the space 807C. The space 807C forms a passage for working oil. When the first land portion 814 falls within a range of the communication port 804C in the axial direction, the communication port 804C is open to both sides of the first land portion 814 in the axial direction so that the communication port 804C is partially open to both of the space 807C and the space 808C. The first land portion 814 moves within a range of the communication port 804C in the axial direction, thus varying the area Si of the above-mentioned opening of the communication port 804C, communicating with the above-mentioned opening of the supply port 803, and the area Sd of the above-mentioned opening of the communication port 804C, communicating with the above-mentioned opening of the drainage port 805.
As shown in
In
Varying the cross-sectional area Sd of the flow passage allows the drainage amount of working oil from the communication port 804C (second control chamber 292) to be varied (adjusted). With such variation, a control hydraulic pressure p is varied (controlled). In this embodiment, simultaneous with the variation in the cross-sectional area Sd, the discharge opening 203 and the communication port 804C (second control chamber 292) are made to communicate with each other. Accordingly, the drainage amount of working oil from the second control chamber 292 varies slowly with respect to the movement of the spool 81C. With the movement of the spool 81C to one side in the axial direction, the control valve 7 increases the cross-sectional area Sd of the flow passage, through which working oil in the second control chamber 292 is drained to the oil pan 400, while decreasing the cross-sectional area Si of the flow passage, through which working oil is introduced from the discharge opening 203 to the second control chamber 292. With the movement of the spool 81C to the other side in the axial direction, the cross-sectional area Sd of the flow passage is decreased while the cross-sectional area Si of the flow passage is increased.
To be more specific, the opening of the communication port 804C (second port) is formed on the inner peripheral surface 800 of the cylinder between the opening of the supply port 803 (first port) and the opening of the drainage port 805 (third port). The spool 81C includes the first land portion 814 which is biased to one side by the solenoid portion 9 and, is biased to the other side by the spring 82C. The first land portion 814 varies the area Si of the above-mentioned opening of the communication port 804C communicating with the above-mentioned opening of the supply port 803, and the area Sd of the above-mentioned opening of the communication port 804C communicating with the above-mentioned opening of the drainage port 805. Accordingly, with such a simpler configuration of a spool valve, the valve portion 8 can control a control hydraulic pressure p. The manner of other operations and advantageous effects are the same as those in the first embodiment. The configuration of this embodiment is also applicable to any embodiment other than the first embodiment.
First, the configuration is described. As shown in
A first control chamber 291A is formed of a space defined between a portion of an outer peripheral surface 245A of the cam ring ranging from the first protrusion 246 to the second protrusion 247 via the third protrusion 248 and the inner peripheral surface of the pump accommodating chamber 200A. A second control chamber 292A is formed of a space defined between a portion of the outer peripheral surface 245A of the cam ring ranging from the first protrusion 246 to the second protrusion 247 via the fourth protrusion 249 and the inner peripheral surface of the pump accommodating chamber 200A. A spring accommodating chamber 293A is integrally formed with the second control chamber 292A, and has a bottomed cylindrical shape. The other end side of the spring 25A is disposed in the spring accommodating chamber 293A. A gap formed between the planar surface of the first protrusion 246 and the planar surface 205 of the pump accommodating chamber 200A, and a gap formed between the planar surface of the second protrusion 247 and the planar surface 206 of the pump accommodating chamber 200A are small and hence, sealing is provided between the first control chamber 291A and the second control chamber 292A (spring accommodating chamber 293A).
The control valve 7 is configured such that, as shown in
Next, the manner of operation is described. The rotor 22A rotates in the clockwise direction in
First, the configuration is described. A pump 2 is configured such that, as shown in
The control valve 7 is configured such that, as shown in
Next, the manner of operation is described. A rotor 22B rotates in the clockwise direction in
A first land portion 811B of a spool 81B varies the opening area of the drainage port 805B, and a second land portion 812B varies the opening area of the supply port 803B. When an electromagnetic force fm is equal to or less than a spring force fs (set load of a spring 82B), as shown in
As described above, the present invention is applicable to the pump 2 having the configuration where the volumes of the first control chamber 291B and the second control chamber 292B increase (a pressure in the second control chamber 292B acts in a direction that an amount of eccentricity Δ is reduced) with the movement of the cam ring 24B in the direction opposing the biasing force Fs of a spring 25B. The characteristic of main gallery hydraulic pressure P with respect to engine speed Ne can be easily caused to approximate the desired characteristic. Additionally, ease of control can be improved. The manner of other operations and advantageous effects are to the same as those in the first embodiment. The configuration of this embodiment is also applicable to an embodiment other than the first embodiment.
First, the configuration is described. The basic configuration of a pump 2 is to the same as that of the first embodiment (
Next, the manner of operation is described. A cam ring 24 is biased by a spring force Fs of a spring 25 to one side in the rotational direction about a pin 27 (to the side where the amount of increase or decrease in volume of each of the plurality of working chambers 28 increases, and the amount of eccentricity Δ increases). The cam ring 24 is biased to the other side in the rotational direction about the pin 27 (to the side where the amount of increase or decrease in volume of each of the plurality of working chambers 28 decreases, and the amount of eccentricity Δ decreases) by a force Fp1 which is caused by a control hydraulic pressure P. When a force Fp1 becomes larger than a spring force Fs, the cam ring 24 oscillates to the other side in the above-mentioned rotational direction and hence, the amount of eccentricity Δ (capacity) reduces. When a force Fp1 becomes smaller than a spring force Fs, the cam ring 24 oscillates to one side in the rotational direction about the pin 27 (to the side where the amount of eccentricity Δ increases) and hence, capacity increases. When an electromagnetic force fm is smaller than a spring force fs, the spool 81 moves to one side in the axial direction toward the initial position so that an amount of working oil drained from the first control chamber 291 increases whereby a force Fp1 decreases. When a force Fp1 is smaller than a spring force Fs, an amount of eccentricity Δ increases. When an electromagnetic force fm is larger than a spring force fs, the spool 81 moves to the other side in the axial direction. Accordingly, working oil is introduced into the first control chamber 291 and, the amount of working oil drained from the first control chamber 291 decreases so that a force Fp1 increases. When a force Fp1 becomes larger than a spring force Fs, an amount of eccentricity Δ decreases.
As described above, the present invention is also applicable to the pump 2 having the configuration where the control mechanism 3 (control valve 7) controls a pressure in the first control chamber 291. The characteristic of main gallery hydraulic pressure P with respect to engine speed Ne can be easily caused to approximate the desired characteristic. Additionally, ease of control can be improved. The manner of other operations and advantageous effects are to the same as those in the first embodiment. The configuration of this embodiment is also applicable to an embodiment other than the first embodiment.
Embodiments for carrying out the present invention have been described heretofore with reference to drawings. However, the specific configuration of the present invention is not limited to any of the above-mentioned embodiments. The present invention also includes embodiments to which design change or the like is added without departing from the gist of the invention. Within a range where at least a portion of the above-mentioned problem can be solved or a range where at least a portion of the above-mentioned advantageous effects can be acquired, respective constitutional elements described in the claims the specification may be arbitrarily combined or omitted. For example, the pump may also be used in a working oil supply system for a mechanical device other than a working oil supply system for an automobile or an engine. The specific configuration of the vane pump is not limited to the embodiments, and may be suitably changed. It is sufficient that the pump is a variable capacity pump, and members other than vanes may be used as pump structures. A member other than a cam ring may be used as a movable member which causes the amount of increase or decrease in volume of each of the plurality of working chambers during the rotation of pump structures to be varied. For example, a pump may be formed of a trochoid gear pump. In this case, by disposing an outer rotor, which is an external gear, so as to allow eccentric movement, and by disposing a control chamber and a spring on the outer peripheral side of the outer rotor, it is possible to realize a variable capacity pump (the outer rotor corresponds to the movable member).
Each of the arithmetic operation portion and the reception portion of the ECU is realized by software in a microcomputer in the embodiments. However, the arithmetic operation portion or the reception portion of the ECU may be realized by an electronic circuit. An arithmetic operation means not only an arithmetic operation using a formula, but also general processing performed on software. The reception portion may be an interface of a microcomputer, or may be software in the microcomputer. A control signal may be a signal relating to a current value, or a signal relating to the thrust of a solenoid. A method for controlling an electric current to be supplied to a solenoid is not limited to PWM control. Current values which correspond to rotational speeds of an engine may be set in advance by a map. Characteristic information which causes a control signal of a solenoid to be varied according to variation in engine speed may be realized by performing an arithmetic operation instead of being realized by a map in a microcomputer.
[Other Aspects which May be Understood Based on Embodiments]
Other aspects which may be understood based on the above-mentioned embodiment are described hereinafter.
(1) In one aspect, a variable capacity pump includes:
a housing including a pump accommodating chamber therein;
a pump structure disposed in the pump accommodating chamber, and configured to vary volumes of a plurality of working chambers with rotation, the pump structure being configured to discharge from a discharge portion working oil introduced from an intake portion by being rotationally driven;
a movable member disposed in the pump accommodating chamber, and accommodating the pump structure to define the plurality of working chambers, the movable member being configured to cause an amount of increase or decrease in volume of each of the plurality of working chambers during rotation of the pump structure to be varied by moving so that an amount of eccentricity of a center of an inner periphery of the movable member from a center of rotation of the pump structure varies;
a first biasing member disposed in the pump accommodating chamber in a state where a set load is applied to the first biasing member, and configured to bias the movable member in a direction that the amount of increase or decrease in volume of each of the plurality of working chambers increases;
a first control chamber which is disposed between the pump accommodating chamber and the movable member, and into which the working oil discharged from the discharge portion is introduced, a volume of the first control chamber increasing with movement of the movable member in a direction opposing a biasing force of the first biasing member;
a second control chamber which is disposed between the pump accommodating chamber and the movable member, and into which the working oil discharged from the discharge portion is introduced through a passage, a volume of the second control chamber being variable with movement of the movable member; and
a control valve provided in the passage, and configured to vary, with movement of a valve element, a cross-sectional area of a flow passage, through which working oil in the second control chamber is drained to a low pressure portion, while making the discharge portion and the second control chamber communicate with each other.
(2) In a more preferred aspect, in the above-mentioned aspect,
with movement of the valve element in a first direction, the control valve increases the cross-sectional area of the flow passage, through which working oil in the second control chamber is drained to the low pressure portion, while decreasing a cross-sectional area of a flow passage, through which working oil is introduced from the discharge portion to the second control chamber.
(3) In another preferred aspect, in any one of the above-mentioned aspects,
with movement of the valve element in a second direction, the control valve decreases the cross-sectional area of the flow passage, through which working oil in the second control chamber is drained to the low pressure portion, while increasing a cross-sectional area of a flow passage through which working oil is introduced from the discharge portion to the second control chamber.
(4) In still another preferred aspect, in any one of the above-mentioned aspects,
the control valve is configured to continuously change a position of the valve element.
(5) In still another preferred aspect, in any one of the above-mentioned aspects,
the control valve is configured to stop the valve element at any position.
(6) In still another preferred aspect, in any one of the above-mentioned aspects,
the control valve includes a solenoid portion configured to generate an electromagnetic force for biasing the valve element.
(7) In still another preferred aspect, in any one of the above-mentioned aspects,
the solenoid portion is configured to move the valve element to any position according to a control signal.
(8) In still another preferred aspect, in any one of the above-mentioned aspects,
the valve element is integrally coupled to a plunger of the solenoid portion.
(9) In still another preferred aspect, in any one of the above-mentioned aspects,
the control valve includes a hollow member which accommodates the valve element, and which has a first port communicating with the discharge portion, a second port communicating with the second control chamber, and a third port communicating with a low pressure portion, openings of the first port, the second port, and the third port being formed on an inner periphery of the hollow member.
(10) In still another preferred aspect, in any one of the above-mentioned aspects,
the control valve includes a solenoid portion configured to generate an electromagnetic force for biasing the valve element, and
the valve element includes
a first land portion disposed on a first port side, and biased to one side by the solenoid portion,
a second land portion disposed on a third port side, and biased to an opposite side by a second biasing member, and
a connecting portion connecting the first land portion and the second land portion with each other.
(11) In still another preferred aspect, in any one of the above-mentioned aspects,
the second land portion varies an area of the opening of the third port as the first land portion varies an area of the opening of the first port.
(12) In still another preferred aspect, in any one of the above-mentioned aspects,
the control valve includes a solenoid portion configured to generate an electromagnetic force for biasing the valve element,
the opening of the second port is disposed between the opening of the first port and the opening of the third port,
the valve element includes a land portion biased to one side by the solenoid portion, and biased to the opposite side by a second biasing member, and
the land portion varies an area of the opening of the second port communicating with the opening of the first port, and an area of the opening of the second port communicating with the opening of the third port.
(13) In still another preferred aspect, in any one of the above-mentioned aspects,
a volume of the second control chamber increases with movement of the movable member in the same direction as a direction of a biasing force of the first biasing member.
(14) In still another preferred aspect, in any one of the above-mentioned aspects,
the movable member includes a first pressure receiving surface facing the first control chamber, and a second pressure receiving surface facing the second control chamber, and having a pressure receiving area larger than a pressure receiving area of the first pressure receiving surface.
(15) In still another preferred aspect, in any one of the above-mentioned aspects,
the movable member is configured to oscillate around a fulcrum in the pump accommodating chamber.
(16) In still another preferred aspect, in any one of the above-mentioned aspects,
the movable member is configured to perform a translational motion in the pump accommodating chamber.
(17) In still another preferred aspect, in any one of the above-mentioned aspects,
a volume of the second control chamber increases with movement of the movable member in a direction opposing the biasing force of the first biasing member.
(18) Further, from another view point, in one aspect, a variable capacity pump includes:
a housing including a pump accommodating chamber therein;
a pump structure disposed in the pump accommodating chamber, and configured to vary volumes of a plurality of working chambers with rotation, the pump structure being configured to discharge from a discharge portion working oil introduced from an intake portion by being rotationally driven;
a movable member disposed in the pump accommodating chamber, and accommodating the pump structure to define the plurality of working chambers, the movable member being configured to cause an amount of increase or decrease in volume of each of the plurality of working chambers during rotation of the pump structure to be varied by moving so that an amount of eccentricity of a center of an inner periphery of the movable member from a center of rotation of the pump structure varies;
a first control chamber which is disposed between the pump accommodating chamber and the movable member, and into which the working oil discharged from the discharge portion is introduced, a volume of the first control chamber increasing with movement of the movable member in one direction;
a second control chamber which is disposed between the pump accommodating chamber and the movable member, and into which the working oil discharged from the discharge portion is introduced through a passage, a volume of the second control chamber being variable with movement of the movable member;
a cylindrical member having a hollow shape, and including a first port communicating with the discharge portion, a second port communicating with the second control chamber, and a third port communicating with a low pressure portion, openings of the first port, the second port, and the third port being formed on an inner periphery of the cylindrical member; and
a control valve including a spool movable in the cylindrical member, and a solenoid portion configured to move the spool.
The spool includes a first large diameter portion configured to vary an area of the opening of the first port, and a second large diameter portion configured to vary an area of the opening of the third port, and the first large diameter portion and the second large diameter portion are disposed on the inner periphery of the cylindrical member within a range sandwiched between the first large diameter portion and the second large diameter portion such that the first port, the second port, and the third port are allowed to be at least partially open simultaneously.
(19) In one aspect, a working oil supply system for an internal combustion engine includes:
a variable capacity pump which introduces working oil discharged from a pump structure into a control chamber disposed around a movable member, which accommodates the pump structure therein, so as to move the movable member to vary an amount of eccentricity of a center of the movable member from a center of rotation of the pump structure, thus varying a pressure of working oil discharged from the pump structure to the internal combustion engine;
a pressure measuring portion configured to measure a pressure of working oil discharged from the pump structure;
a rotational speed measuring portion configured to measure a rotational speed of the internal combustion engine; and
a control portion which calculates a pressure difference between a pressure measured by the pressure measuring portion and a pressure of working oil which the internal combustion engine is required to have at the rotational speed measured by the rotational speed measuring portion, the control portion varying, when the rotational speed is equal to or more than a predetermined rotational speed and the pressure difference is larger than a predetermined pressure difference, a drainage amount of working oil from the control chamber to a low pressure portion while allowing working oil to be introduced into the control chamber until the pressure difference becomes equal to or less than the predetermined pressure difference.
(20) In a more preferred aspect, in the above-mentioned aspect,
the control portion does not drain working oil from the control chamber to the low pressure portion when the rotational speed is less than the predetermined rotational speed.
(21) In another preferred aspect, in any one of the above-mentioned aspects,
the control portion controls, when the rotational speed is equal to or more than the predetermined rotational speed and the pressure difference is equal to or less than the set pressure difference, a drainage amount of working oil from the control chamber to the low pressure portion at a predetermined fixed amount until the pressure difference becomes larger than the set pressure difference.
This application claims priority to Japanese patent application No. 2016-181736 filed on Sep. 16, 2016. The entire disclosure, including the specification, the claims, the drawings, and the abstract of Japanese patent application No. 2016-181736 filed on Sep. 16, 2016 is incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-181736 | Sep 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/028361 | 8/4/2017 | WO | 00 |
