JP2014105648A - Internal gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal gear pump capable of sufficiently suppressing increase of driving force for rotating and driving an external gear according to increase of a rotational frequency of the external gear by increasing a reflowing amount to a low pressure-side, of a liquid discharged from a discharge port according to the increase of the rotational frequency of the external gear.SOLUTION: At least three discharge ports 13A, 13B, 13C communicated with a discharge area space P and discharging a liquid, are opened while separating from each other in the rotating direction of gears 3, 4. An initial form in which all of discharge ports 13A-13C are connected to the same load side, an intermediate form in which discharge ports disconnected from the load side and connected with a tank T are successively increased by the third discharge port 13C and the second discharge port 13B, and a final form in which one discharge port 13A is connected to the load side and the remaining discharge ports 13B, 13C are disconnected from the load side and connected to the tank T, are switchable according to the increase of the rotational frequency for rotating and driving the external gear 4.

Description

  The present invention relates to an internal gear pump in which an external gear is eccentrically housed inside an internal gear so that the internal teeth of the internal gear and the external teeth of the external gear mesh with each other.

  In this type of internal gear pump, a ring-shaped internal gear having internal teeth is rotatably accommodated in an accommodation hole of the pump housing, and an external tooth having external teeth that mesh with the internal teeth of the internal gear. The toothed gear is eccentrically housed inside the internal gear, opens the suction port in communication with the suction area space where the meshing gap between both teeth increases as both gears rotate, and the meshing gap between both teeth The maximum volume area in which the first discharge port and the second discharge port are opened to communicate with the decreasing discharge area space, and the meshing gap between both teeth is maximized between the suction area space and the discharge area space. A space is formed. Moreover, the control valve which can be switched to a 1st form and a 2nd form is comprised. Then, the oil as the liquid sucked into the suction area space by the rotation driving of the external gear is transported from the maximum volume area space to the discharge area space and discharged from the first discharge port and the second discharge port, and the external gear rotates. When the number is low-speed rotation and the hydraulic pressure of the first discharge port is lower than the predetermined pressure, the control valve is in the first form, and the oil discharged from the first discharge port and the oil discharged from the second discharge port are merged. To the load. Further, when the rotation speed of the external gear becomes high speed rotation and the hydraulic pressure of the first discharge port becomes higher than a predetermined pressure, the control valve becomes the second form, and the oil discharged from the second discharge port is set to the low pressure side. Only the oil that is returned to the tank and discharged and discharged from the first discharge port is fed to the load. In this way, when the rotational speed increases, the oil from the second discharge port is returned to the tank to suppress an increase in the discharge amount, and an increase in driving force for rotationally driving the external gear is suppressed.

JP-A-9-126153

  However, in such a conventional internal gear pump, since there are two discharge ports, the first discharge port and the second discharge port, an increase in the discharge amount is sufficiently suppressed as the rotational speed of the external gear increases. The increase in the driving force for rotationally driving the external gear cannot be suppressed to a satisfactory level.

  The object of the present invention is to increase the amount of liquid discharged from the discharge port to the low pressure side as the rotational speed of the external gear increases, and to rotate the external gear as the rotational speed of the external gear increases. An internal gear pump that can sufficiently suppress an increase in driving force to be driven is provided.

In order to achieve this problem, the present invention has taken the following measures. That is,
A ring-shaped internal gear having internal teeth is rotatably accommodated in the housing hole of the pump housing, and the external gear having external teeth that are in mesh with the internal teeth of the internal gear is eccentric to the internal gear. The external gear is driven to rotate by the drive shaft, and a suction area space is formed between the two gears in the region where the meshing gap between the two teeth increases due to the rotation of the two gears. A discharge area space is formed in an area where the meshing clearance of the internal gear decreases, and a pump chamber is defined by the internal teeth of the internal gear and the external teeth of the external gear, and the pump chamber has a volume in the suction area space by the rotation of both gears. And a suction port for sucking liquid in communication with the suction area space on the sliding contact surface of the pump housing where the side surfaces of both gears received in the accommodation hole are in sliding contact with each other. At the same time as communicating with the discharge area space. Disposed at least three discharge ports that are spaced apart in the rotational direction of both gears, and an initial configuration in which all discharge ports are connected to the same load side, and one discharge port is connected to the load side and remains A final configuration in which the discharge port is disconnected from the load side and connected to the low pressure side, and an intermediate configuration in which the discharge port that is disconnected from the load side and connected to the low pressure side is sequentially increased between the initial configuration and the final configuration. The internal gear pump is characterized in that it can be switched from the initial form to the final form through the intermediate form in accordance with the increase in the rotational speed for rotationally driving the external gear.

  In this case, the number of the discharge ports may be four or more and the same number as the number of the pump chambers located in the discharge area space.

  As described in detail above, the invention described in claim 1 is provided with discharge ports that communicate with the discharge area space and discharge liquid, spaced apart in the rotational direction of both gears, and provided with at least three openings. An initial configuration in which discharge ports are connected to the same load side, a final configuration in which one discharge port is connected to the load side and the remaining discharge ports are disconnected from the load side and connected to the low pressure side, and an initial configuration and final configuration The intermediate port has an intermediate configuration that sequentially increases the discharge port connected to the low pressure side by cutting off from the load side, and from the initial configuration to the final configuration according to the increase in the number of rotations for rotationally driving the external gear. Changeable to form. For this reason, the amount of liquid recirculated from the discharge port to the low pressure side can be increased sequentially as the rotational speed of the external gear increases, so that the discharge of liquid fed from the discharge port to the load side is contrary to this. An increase in the amount can be sufficiently suppressed, and an increase in driving force for rotationally driving the external gear according to an increase in the rotational speed of the external gear can be sufficiently suppressed.

  In the invention according to claim 2, the number of discharge ports is four or more and is the same as the number of pump chambers located in the discharge area space. For this reason, since the amount of liquid discharged from the discharge port to the low pressure side can be increased sequentially as the rotational speed of the external gear increases to a higher rotation range, it is contrary to this and sent from the discharge port to the load side. The increase in the discharge amount of the liquid to be supplied can be sufficiently suppressed to a higher rotation range, and the increase in the driving force for rotating the external gear according to the increase in the rotation speed of the external gear can be sufficiently suppressed to the higher rotation range. be able to.

It is sectional drawing which showed a part of internal gear pump which showed one Embodiment of this invention with the hydraulic circuit diagram. The pump characteristics of FIG. 1 are shown, in which (A) is a discharge amount-rotation speed characteristic chart, and (B) is a rotational drive force-rotation speed characteristic chart. It is sectional drawing which showed a part which showed other embodiment with the hydraulic circuit diagram. FIG. 3 shows the pump characteristics of FIG. 3, (A) is a characteristic chart of discharge amount-rotation speed, and (B) is a characteristic chart of rotational driving force-rotation speed. It is sectional drawing which showed a part which showed further embodiment with the hydraulic circuit diagram. FIG. 5 shows the pump characteristics of FIG. 5, (A) is a characteristic chart of discharge amount-rotation speed, and (B) is a characteristic chart of rotational driving force-rotation speed.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a pump housing having a receiving hole 2. Reference numeral 3 denotes a ring-shaped internal gear, which has ten internal teeth 3 </ b> A and is rotatably accommodated in the accommodation hole 2. Reference numeral 4 denotes an external gear, which has nine external teeth 4A which are in mesh with the internal teeth 3A and have one fewer teeth than the internal teeth 3A, and are eccentrically housed inside the internal gear 3 and accommodated rotatably. ing. The bottom surface of the housing hole 2 is used as a sliding contact surface of the pump housing 1 where the side surfaces of both gears 3 and 4 are in sliding contact. The external gear 4 has a through-hole 5 penetrating in the axial direction at the center, and convex portions 6 and 7 projecting radially inward at two locations facing the radial direction of the through-hole 5.

  A drive shaft 8 is inserted into the through-hole 5 of the external gear 4. The concave portions 9, 10 are formed in two radially opposite positions, and the convex portions 6, 7 of the external gear 4 are formed in the concave portions 9, 10. The external gear 4 is rotationally driven by engaging. S is a suction area space, P is a discharge area space, M is a maximum volume space, and N is a minimum volume space. The suction zone space S is formed in a region where the meshing gap between the teeth 3A and 4A increases as the gears 3 and 4 rotate. The discharge area space P is formed in an area where the meshing gap between the teeth 3A, 4A is reduced by the rotation of the gears 3, 4. The maximum volume space M is formed between the suction area space S and the discharge area space P in an area where the meshing gap between the teeth 3A and 4A is maximized by the rotation of the gears 3 and 4. The minimum volume space N is formed in a region where both teeth 3A and 4A are engaged with each other in the deepest direction, facing the maximum volume space M in the radial direction. Reference numeral 11 denotes a suction port communicating with the suction area space S. The suction port 11 is formed in a recess in the bottom surface of the accommodation hole 2 of the pump housing 1 and is connected to the tank T on the low pressure side to suck oil as liquid in the tank T. .

  13A, 13B, and 13C are three first to third discharge ports communicating with the discharge area space P. The first and third discharge ports are spaced apart from each other in the rotational direction A of the gears 3 and 4 on the bottom surface of the housing hole 2 of the pump housing 1. A recess is formed and opened, and oil is discharged to a load side (not shown). The first discharge port 13A is connected to the load side via the first connection flow path 14A. The second discharge port 13B is connected to the load side via a second connection channel 14B that is branched and connected to the first connection channel 14A. The third discharge port 13C is connected to the load side via a third connection channel 14C that branches and connects to the first connection channel 14A. Reference numeral 15A denotes a first check valve disposed in the second connection flow path 14B, which allows a flow from the second discharge port 13B to the first connection flow path 14A and from the first connection flow path 14A to the second. Is provided in a direction to prevent the flow to the discharge port 13B. Reference numeral 15B denotes a second check valve disposed in the third connection flow path 14C, which allows the flow from the third discharge port 13C to the first connection flow path 14A and from the first connection flow path 14A to the third connection flow path. Is provided in a direction to prevent the flow to the discharge port 13C.

  16A is a first discharge channel that connects the second connection channel 14B to the tank T, and is connected to the second discharge port 13B side from the location of the first check valve 15A of the second connection channel 14B. Yes. 16B is a second discharge channel that connects the third connection channel 14C to the tank T, and is connected to the third discharge port 13C side from the location of the second check valve 15B of the third connection channel 14C. Yes. Reference numeral 17A denotes a first electromagnetic valve disposed in the first discharge flow path 16A. The first electromagnetic valve opens when energized to communicate between the second connection flow path 14B and the tank T, and closes when de-energized to operate second. The connection flow path 14B and the tank T are blocked. Reference numeral 17B denotes a second electromagnetic valve disposed in the second discharge flow path 16B. The second solenoid valve opens when energized to communicate between the third connection flow path 14C and the tank T, and closes when deenergized. The connection channel 14C and the tank T are blocked.

  An initial configuration in which all of the first to third discharge ports 13A, 13B, and 13C are connected to the same load side, and one first discharge port 13A is connected to the load side and the remaining second and third The third discharge port 13C is a final configuration in which the discharge ports 13B and 13C are disconnected from the load side and connected to the tank T, and the discharge port that is disconnected from the load side and connected to the tank T between the initial configuration and the final configuration. In addition, the second discharge port 13B is added to the intermediate form that increases sequentially. In the initial configuration, the first electromagnetic valve 17A and the second electromagnetic valve 17B are both closed to shut off the second connection flow path 14B, the third connection flow path 14C and the tank T. In the intermediate configuration, the second electromagnetic valve 17B is opened to communicate between the third connection flow path 14C and the tank T, and the first electromagnetic valve 17A is closed to activate the second connection flow path 14B and the tank T. Between the two. In the final configuration, the first solenoid valve 17A and the second solenoid valve 17B are both opened to communicate between the second connection flow path 14B, the third connection flow path 14C and the tank T. And according to the raise of the rotation speed which rotationally drives the external gear 4, it makes it possible to switch from the initial form to the final form through the intermediate form.

  V is a pump chamber, which is defined by the internal teeth 3A of the internal gear 3 and the external teeth 4A of the external gear 4, and increases the volume in the suction area S by the rotation of both gears 3 and 4, and the maximum volume space The volume is maximized at M, the volume is decreased at the discharge area P, and the volume is minimized at the minimum volume N. In the discharge area space P, four first to fourth pump chambers V1 to V4 whose volumes are sequentially reduced from the maximum volume space M side to the minimum volume space N side are located. The first pump chamber V1 is connected to the first discharge port 13A, the second pump chamber V2 and the third pump chamber V3 are connected to the second discharge port 13B, and the fourth pump chamber V4 is the third pump port. The discharge port 13C is connected.

Next, the operation of this configuration will be described.
When the external gear 4 is rotationally driven in the rotational direction A by the drive shaft 8, the internal gear 3 that is in mesh with the external gear 4 is rotationally driven, and the oil in the tank T is volumetric in the suction area S from the suction port 11. The pump chamber V is increased and is transferred to the discharge region space P through the maximum volume space M. In the discharge region space P, the pump chambers V1 to V4 reduce the volume, so that the three discharge ports 13A, 13B, Discharge from 13C.

  Now, until the rotational speed of the external gear 4 reaches the first set value A (1500 rpm) shown in FIG. 2A, both the first electromagnetic valve 17A and the second electromagnetic valve 17B are in the closed operation state. Then, the second connection flow path 14B, the third connection flow path 14C and the tank T are blocked, and the oil discharged from the first discharge port 13A flows through the first connection flow path 14A, and the second discharge port The oil discharged from 13B flows through the second connection flow path 14B and the first check valve 15A to join the first connection flow path 14A, and the oil discharged from the third discharge port 13C is the third connection flow path. 14C flows through the second check valve 15B, joins the first connection flow path 14A, and the oil discharged from all the first to third discharge ports 13A, 13B, 13C is supplied to the load side. As the rotational speed increases, the discharge amount increases as shown in FIG. 2A, and the rotational driving force for rotationally driving the external gear 4 increases as shown in FIG. 2B.

  Now, when the rotational speed of the external gear 4 reaches the first set value A, an intermediate configuration is established, the second electromagnetic valve 17B is opened to communicate between the third connection flow path 14C and the tank T, The first electromagnetic valve 17A maintains a closed operation state and blocks between the second connection flow path 14B and the tank T. Oil discharged from the first discharge port 13A flows through the first connection flow path 14A, and oil discharged from the second discharge port 13B flows through the second connection flow path 14B and the first check valve 15A to the first. The oil that joins the connection flow path 14A and is discharged from the first discharge port 13A and the second discharge port 13B is supplied to the load side, and the discharge amount increases as the rotational speed increases. At this time, since the third connection flow path 14C is connected to the tank T and has a lower pressure than the first connection flow path 14A, the oil discharged from the third discharge port 13C is first in the second check valve 15B. The flow to the connection flow path 14A side is blocked, and the second electromagnetic valve 17B that has been opened flows through the second discharge flow path 16B and is discharged to the tank T. Then, as shown in FIG. 2A, the discharge amount is reduced by the oil discharged from the third discharge port 15C at the first set value A being discharged to the tank T, and then the rotation speed is increased. Increase with. Further, as shown in FIG. 2 (B), the rotational driving force is reduced by discharging the oil discharged from the third discharge port 15C to the tank T at the first set value A, and thereafter the rotational speed is reduced. Increase with the rise.

  Now, when the rotational speed of the external gear 4 reaches the second set value B (3500 rpm) which is higher than the first set value A, the final form is reached, and the first solenoid valve 17A is opened in addition to the second solenoid valve 17B. The second connection channel 14B is connected to the tank T in addition to the third connection channel 14C. Oil discharged from the first discharge port 13A flows through the first connection flow path 14A and is supplied to the load side. At this time, in addition to the third connection flow path 14C, the second connection flow path 14B is connected to the tank T and has a lower pressure than the first connection flow path 14A, so that it is discharged from the third discharge port 13C to the tank T. In addition to the discharged oil, the oil discharged from the second discharge port 13B is prevented from flowing toward the first connection flow path 14A by the first check valve 15A, and is opened from the first electromagnetic valve 17A that is opened. It flows through the first discharge channel 16A and is discharged to the tank T. 2A, the oil discharged from the second discharge port 15B is discharged into the tank T in addition to the oil discharged from the third discharge port 15C at the second set value B as shown in FIG. After that, it increases as the rotational speed increases. Further, as shown in FIG. 2B, the rotational driving force is the second set value B, and the oil discharged from the second discharge port 15B is discharged to the tank T in addition to the oil discharged from the third discharge port 15C. And then increases as the rotational speed increases.

  With this operation, at least three discharge ports 13A, 13B, 13C communicating with the discharge area space P and discharging oil are provided apart from each other in the rotational direction of the gears 3, 4, and all the discharge ports 13A are provided. , 13B, and 13C are connected to the same load side, and the final form is that one discharge port 13A is connected to the load side and the remaining discharge ports 13B and 13C are disconnected from the load side and connected to the tank T. The external gear has an intermediate configuration in which the discharge port connected to the tank T by being disconnected from the load side between the initial configuration and the final configuration is sequentially increased to the third discharge port 13C and the second discharge port 13B. In accordance with the increase in the rotational speed for rotationally driving 4, the initial form can be switched to the final form through the intermediate form. For this reason, the amount of oil recirculated from the discharge ports 13A, 13B, 13C to the tank T can be sequentially increased in accordance with the increase in the rotational speed of the external gear 4, so that the discharge ports 13A, 13B, It is possible to sufficiently suppress an increase in the amount of oil discharged from 13C to the load side, and to sufficiently suppress an increase in driving force that rotationally drives the external gear 4 in accordance with an increase in the rotational speed of the external gear 4. it can.

FIG. 3 shows another embodiment of the present invention. The same reference numerals are given to the same portions as those of the first embodiment, the description thereof is omitted, and only different portions will be described.
Four first to fourth discharge ports 18A, 18B, 18C, 18D communicating with the discharge area space P are spaced apart from each other in the rotational direction A of the gears 3, 4 on the bottom surface of the housing hole 2 of the pump housing 1. A recess is formed and opened. The first discharge port 18A is connected to the first pump chamber V1, and is connected to the load side via the first connection flow path 19A. The second discharge port 18B is connected to the second pump chamber V2, and is connected to the load side via a second connection flow path 19B branchingly connected to the first connection flow path 19A. The third discharge port 18C is connected to the third pump chamber V3, and is connected to the load side via a third connection channel 19C branchingly connected to the first connection channel 19A. The fourth discharge port 18D is connected to the fourth pump chamber V4, and is connected to the load side via a fourth connection flow path 19D that branches and connects to the first connection flow path 19A. That is, in the pump of the first embodiment, the second discharge port 13B is connected to the second pump chamber V2 and the third pump chamber V3, whereas in the present embodiment, the first to fourth pumps are connected. The discharge ports 18A to 18D are respectively connected to the first to fourth pump chambers V1 to V4.

  The first to third check valves 20A to 20C are disposed in the second to fourth connection flow paths 19B to 19D, and the second to fourth discharge ports 18B to 18D are connected to the first connection flow path 14A. While permitting the flow, it is provided in such a direction as to prevent the flow from the first connection flow path 14A to the second to fourth discharge ports 18B to 18D. In addition, the first to third discharge channels 21A to 21C are connected to the discharge ports 18B to 18D from the locations where the check valves 20A to 20C are disposed in the second to fourth connection channels 19B to 19D, Each discharge channel 21A to 21C is connected to the tank T. The first to third discharge passages 21A to 21C are provided with first to third solenoid valves 22A to 22C, and are opened by energization to communicate between the connection passages 19B to 19D and the tank T. At the same time, it is closed by non-energization to shut off the connection flow paths 19B to 19D and the tank T.

  An initial configuration in which all the first to fourth discharge ports 18A, 18B, 18C, and 18D are connected to the same load side, and one first discharge port 18A is connected to the load side and the remaining second and second 3. The final form in which the fourth discharge ports 18B, 18C, 18D are disconnected from the load side and connected to the tank T, and the discharge port that is disconnected from the load side and connected to the tank T between the initial form and the final form The third discharge port 18C and the second discharge port 18B are sequentially added to the fourth discharge port 18D to increase the intermediate form. In the initial configuration, all the electromagnetic valves 22A, 22B, and 22C are closed to shut off the second to fourth connection flow paths 19B to 19D and the tank T. In the intermediate configuration, the third electromagnetic valve 22C is opened to communicate between the fourth connection flow path 19D and the tank T, and the second electromagnetic valve 22B and the first electromagnetic valve 22A are closed to operate the third connection flow. From the first state in which the path 19C and the second connection flow path 19B are disconnected from the tank T, the third electromagnetic valve 22C and the second electromagnetic valve 22B are opened to operate the fourth connection flow path 19D and the third connection flow. While communicating between the path 19C and the tank T, the first electromagnetic valve 22A is closed to shift to the second state in which the connection between the second connection flow path 19B and the tank T is blocked. In the final form, the first to third electromagnetic valves 22A to 22C are opened to communicate between the second to fourth connection flow paths 19B to 19D and the tank T. And according to the raise of the rotation speed which rotationally drives the external gear 4, it makes it possible to switch from the initial form to the final form through the intermediate form.

  In operation, the oil in the tank T is sucked into the pump chamber V whose volume is increased in the suction area space S from the suction port 11 and is conveyed to the discharge area space P through the maximum volume space M, and the pump chamber V1 in the discharge area space P. -V4 discharges from four discharge ports 18A, 18B, 18C, 18D by reducing the volume.

  Now, until the rotational speed of the external gear 4 reaches the first set value A1 (1500 rpm) shown in FIG. 4 (A), the first to third solenoid valves 22A to 22C are all in the closed operation state. The oil discharged from all the first to fourth discharge ports 18A to 18D merges and is supplied to the load side. As the rotational speed increases, the discharge amount and the rotational driving force for rotationally driving the external gear 4 increase as shown in FIGS.

  Now, when the rotational speed of the external gear 4 reaches the first set value A1, the first state of the intermediate form is entered, the third electromagnetic valve 22C is opened, and the second electromagnetic valve 22B and the first electromagnetic valve 22A are The closed operation state is maintained, the oil discharged from the first to third discharge ports 18A to 18C merges and is supplied to the load side, and the discharge amount increases as the rotational speed increases. At this time, the oil discharged from the fourth discharge port 18D flows through the third discharge passage 21C and is discharged to the tank T. The discharge amount and the rotational driving force are reduced by discharging the oil discharged from the fourth discharge port 18D to the tank T at the first set value A1, as shown in FIGS. Thereafter, it increases as the rotational speed increases.

  Now, when the rotation speed of the external gear 4 reaches the second set value B1 (2500 rpm), the second state of the intermediate configuration is entered, and the third and second electromagnetic valves 22C and 22B are opened and the first electromagnetic valve is operated. 22A maintains the closed operation state, the oil discharged from the first and second discharge ports 18A, 18B merges and is supplied to the load side, and the discharge amount increases as the rotational speed increases. At this time, the oil discharged from the fourth and third discharge ports 18D and 18C flows through the third and second discharge passages 21C and 21B and is discharged to the tank T. The discharge amount and the rotational driving force are oil discharged from the third discharge port 18C in addition to the oil discharged from the fourth discharge port 18D at the second set value B1, as shown in FIGS. Is reduced by being discharged into the tank T, and thereafter increases with an increase in the rotational speed.

  Now, when the rotation speed of the external gear 4 reaches the third set value C1 (4000 rpm), the final form is reached, and all the solenoid valves 22C to 22A are opened, and the fourth to second discharge ports 18D to 18B are operated. The discharged oil is discharged to the tank T, and only the oil discharged from the first discharge port 18A is supplied to the load side. As shown in FIGS. 4A and 4B, the discharge amount and the rotational driving force are discharged from the second discharge port 18B in addition to the oil discharged from the fourth and third discharge ports 18D and 18B at the third set value C1. The oil to be discharged is reduced by being discharged to the tank T, and thereafter increases with an increase in the rotational speed.

  With this operation, the discharge ports 18A to 18D communicating with the discharge area space P and discharging oil are provided in the rotation direction of the two gears 3 and 4 so that at least four of them are opened and all the discharge ports are provided. An initial configuration in which the ports 18A to 18D are connected to the same load side, and a final discharge state in which one discharge port 18A is connected to the load side and the remaining discharge ports 18B, 18C, 18D are disconnected from the load side and connected to the tank T. And an intermediate configuration in which the discharge port connected to the tank T is disconnected from the load side between the initial configuration and the final configuration and the fourth discharge port 18D and the third discharge port 18C are sequentially increased, In accordance with an increase in the rotational speed for rotating the toothed gear 4, the initial form can be switched to the final form through the intermediate form. For this reason, the amount of oil recirculated from the discharge ports 18A, 18B, 18C, 18D to the tank T can be sequentially increased as the rotational speed of the external gear 4 increases, so that the discharge ports 18A, 18B, 18C, 18D can sufficiently suppress an increase in the amount of oil delivered to the load side, and sufficiently increase the driving force for driving the external gear 4 to rotate in response to an increase in the rotational speed of the external gear 4. Can be suppressed.

  The number of discharge ports 18A to 18D is four or more, and is the same as the number of pump chambers V1 to V4 located in the discharge area space P. For this reason, the amount of the liquid discharged from the discharge ports 18A to 18D to be returned to the tank T can be sequentially increased as the rotational speed of the external gear 4 increases to a higher rotation range. The increase in the discharge amount of the liquid fed from 18D to the load side can be sufficiently suppressed to a higher rotation range, and an increase in the driving force for rotationally driving the external gear 4 according to the increase in the rotational speed of the external gear 4 can be increased. It is possible to sufficiently suppress even a higher rotation range.

FIG. 5 shows still another embodiment of the present invention. The same portions as those of the above-described embodiments are denoted by the same reference numerals, description thereof is omitted, and only different portions will be described.
The internal gear 31 has 12 internal teeth 31A. The external gear 41 has 11 external teeth 41A that are in mesh with the internal teeth 31A, and is one fewer than the internal teeth 31A. In the discharge area space P, five first to fifth pump chambers V1 to V5 whose volumes are sequentially reduced from the maximum volume space M side to the minimum volume space N side are located. Further, the five first to fifth discharge ports 23A, 23B, 23C, 23D, and 23E communicating with the discharge area space P are provided on the bottom surface of the housing hole 2 of the pump housing 1, and the rotational direction A of both the gears 31 and 41 is set. The first to fifth discharge ports 23A to 23E are connected to the first to fifth pump chambers V1 to V5, respectively. The first discharge port 23A is connected to the load side via the first connection flow path 24A, and the second to fifth discharge ports 23B to 23E are branched to the first connection flow path 24A, respectively. It is connected to the load side via the fifth connection flow paths 24B to 24E.

  The first to fourth check valves 25A to 25D are disposed in the second to fifth connection flow paths 24B to 24E, and the second to fifth discharge ports 23B to 23E are connected to the first connection flow path 24A. While permitting the flow, it is provided in a direction to prevent the flow from the first connection flow path 24A to the second to fifth discharge ports 23B to 23E. In addition, the first to fourth discharge flow paths 26A to 26D are connected to the discharge ports 23B to 23E from the locations where the check valves 25A to 25D are disposed in the second to fifth connection flow paths 24B to 24E, Each discharge channel 21A to 21C is connected to the tank T. The first to fourth discharge channels 26A to 26D are provided with first to fourth solenoid valves 27A to 27D, which are opened by energization to communicate between the connection channels 24B to 24E and the tank T. At the same time, it is closed by non-energization to shut off the connection flow paths 24B to 24E and the tank T.

  An initial configuration in which all five discharge ports 23A to 23E are connected to the same load side, and one second discharge port 24A to the load side and the remaining second to fifth discharge ports 23B to 23E. And the discharge port connected to the tank T between the initial form and the final form and connected to the tank T between the initial form and the final form is connected to the fifth discharge port 23E as the fourth discharge. It has an intermediate configuration in which the port 23B, the third discharge port 23C, and the second discharge port 23B are sequentially added and increased. In the initial configuration, all the solenoid valves 27A to 27D are closed to shut off the second to fifth connection flow paths 24B to 24E and the tank T. In the intermediate configuration, the fourth solenoid valve 27D is opened to communicate between the fifth connection flow path 24E and the tank T, and the third solenoid valve 27C to the first solenoid valve 27A are closed to actuate the fourth connection flow. From the first state in which the path 24D to the second connection flow path 24B and the tank T are blocked, the fourth solenoid valve 27D and the third solenoid valve 27C are opened to operate the fifth connection flow path 24E and the fourth connection flow. The channel 24D communicates with the tank T, and the second solenoid valve 27B and the first solenoid valve 27A are closed to shut off the third connection channel 24C, the second connection channel 24B, and the tank T. The second electromagnetic valve 27D to the second electromagnetic valve 27B are opened to communicate between the fifth connection flow path 24E to the third connection flow path 24C and the tank T, and A third shape in which the first electromagnetic valve 27A is closed to shut off the connection between the second connection flow path 24B and the tank T. To migrate to. In the final configuration, the first to fourth electromagnetic valves 27A to 27D are opened to communicate between the second to fifth connection flow paths 24B to 24E and the tank T. And according to the raise of the rotation speed which rotationally drives the external gear 41, it can be switched to a final form from an initial form through an intermediate form.

  In operation, the oil in the tank T is sucked into the pump chamber V whose volume is increased in the suction area space S from the suction port 11 and is conveyed to the discharge area space P through the maximum volume space M, and the pump chamber V1 in the discharge area space P. -V5 discharges from five discharge ports 23A-23E by reducing the volume.

  Now, until the rotational speed of the external gear 41 reaches the first set value A2 (1200 rpm) shown in FIG. 6A, the first to fourth solenoid valves 27A to 27D are all in the closed operation state. The oil discharged from all the first to fifth discharge ports 23A to 23E merges and is supplied to the load side. As the rotational speed increases, as shown in FIGS. 6A and 6B, the discharge amount and the rotational driving force for rotationally driving the external gear 41 increase.

  Now, when the rotation speed of the external gear 41 reaches the first set value A2, the first state of the intermediate form is entered, the fourth electromagnetic valve 27D is opened, and the third electromagnetic valve 27C to the first electromagnetic valve 27A are The closed operation state is maintained, and the oil discharged from the first to fourth discharge ports 23A to 23D merges and is supplied to the load side, and the discharge amount increases as the rotational speed increases. At this time, the oil discharged from the fifth discharge port 23E flows through the fourth discharge flow path 26D and is discharged to the tank T. The discharge amount and the rotational driving force are reduced by discharging the oil discharged from the fifth discharge port 23E to the tank T at the first set value A2, as shown in FIGS. Thereafter, it increases as the rotational speed increases.

  Now, when the rotational speed of the external gear 41 reaches the second set value B2 (2000 rpm), the second state of the intermediate form is entered, the fourth and third electromagnetic valves 27D and 27C are opened, and the second and second 1 Solenoid valves 27B and 27A maintain a closed operation state, the oil discharged from the first to third discharge ports 23A to 23C merges and is supplied to the load side, and the discharge amount increases as the rotational speed increases. . At this time, the oil discharged from the fifth and fourth discharge ports 23E and 23D flows through the fourth and third discharge passages 26D and 26C and is discharged to the tank T. The discharge amount and the rotational driving force are oil discharged from the fourth discharge port 23D in addition to oil discharged from the fifth discharge port 23E at the second set value B2, as shown in FIGS. Is reduced by being discharged into the tank T, and thereafter increases with an increase in the rotational speed.

  Now, when the rotation speed of the external gear 41 reaches the third set value C2 (2900 rpm), the third state of the intermediate form is entered, and the fourth to second solenoid valves 27D to 27B are opened and the first solenoid valve is operated. 27A maintains a closed operation state, the oil discharged from the first and second discharge ports 23A and 23B merges and is supplied to the load side, and the discharge amount increases as the rotational speed increases. At this time, the oil discharged from the fifth to third discharge ports 23E to 23C flows through the fourth to second discharge passages 26D to 26B and is discharged to the tank T. As shown in FIGS. 6A and 6B, the discharge amount and the rotational driving force are set to the third discharge port in addition to the oil discharged from the fifth and fourth discharge ports 23E and 23D at the third set value C2. The oil discharged from 23C is reduced by being discharged into the tank T, and thereafter increases with an increase in the rotational speed.

  Now, when the rotation speed of the external gear 4 reaches the fourth set value D2 (4000 rpm), the final form is reached, all the solenoid valves 27D to 27A are opened, and the fifth to second discharge ports 23E to 23B are operated. The discharged oil is discharged to the tank T, and only the oil discharged from the first discharge port 23A is supplied to the load side. The discharge amount and the rotational driving force are discharged from the second discharge port 23B in addition to the oil discharged from the fifth to third discharge ports 23E to 23C at the fourth set value D2, as shown in FIGS. The oil to be discharged is reduced by being discharged to the tank T, and thereafter increases with an increase in the rotational speed.

  With this operation, the amount of liquid recirculated from the discharge ports 23A, 23B, 23C, 23D, and 23E to the tank T of the liquid is sequentially increased as the rotational speed of the external gear 41 increases as in the above-described embodiments. Therefore, contrary to this, an increase in the amount of oil discharged from the discharge ports 23A, 23B, 23C, 23D, and 23E to the load side can be sufficiently suppressed, and the external speed increases as the rotational speed of the external gear 41 increases. An increase in driving force for rotationally driving the toothed gear 41 can be sufficiently suppressed.

  The number of discharge ports 23A to 23E is four, five or more, and is the same as the number of pump chambers V1 to V5 located in the discharge area space P. For this reason, the amount of oil returned from the discharge ports 23A to 23E to the tank T can be increased in sequence as the rotational speed of the external gear 41 is increased to a higher rotation range. The increase in the discharge amount of oil fed from 23A to 23E to the load side can be sufficiently suppressed to a higher rotational speed range, and the driving force for rotationally driving the external gear 41 as the rotational speed of the external gear 41 increases. The increase can be sufficiently suppressed to a higher rotation range.

  In one embodiment, three discharge ports 13A to 13C are provided, in another embodiment, four discharge ports 18A to 18D are provided, and in another embodiment, five discharge ports 23A to 23E are provided. However, the present invention is not limited to these, and it is a matter of course that the number of discharge ports may be six or seven as long as it is at least three or more.

1: pump housing 2: accommodation hole 3, 31: internal gear 3A, 31A: internal gear 4, 41: external gear 4A, 41A: external gear 11: suction port 13A, 13B, 13C, 18A, 18B, 18C, 18D, 23A, 23B, 23C, 23D, 23E: Discharge port S: Suction area space P: Discharge area space V, V1, V2, V3, V4, V5: Pump chamber

Claims (2)

  A ring-shaped internal gear having internal teeth is rotatably accommodated in the housing hole of the pump housing, and the external gear having external teeth that are in mesh with the internal teeth of the internal gear is eccentric to the internal gear. The external gear is driven to rotate by the drive shaft, and a suction area space is formed between the two gears in the region where the meshing gap between the two teeth increases due to the rotation of the two gears. A discharge area space is formed in an area where the meshing clearance of the internal gear decreases, and a pump chamber is defined by the internal teeth of the internal gear and the external teeth of the external gear, and the pump chamber has a volume in the suction area space by the rotation of both gears. And a suction port for sucking liquid in communication with the suction area space on the sliding contact surface of the pump housing where the side surfaces of both gears received in the accommodation hole are in sliding contact with each other. At the same time as communicating with the discharge area space. Disposed at least three discharge ports that are spaced apart in the rotational direction of both gears, and an initial configuration in which all discharge ports are connected to the same load side, and one discharge port is connected to the load side and remains A final configuration in which the discharge port is disconnected from the load side and connected to the low pressure side, and an intermediate configuration in which the discharge port that is disconnected from the load side and connected to the low pressure side is sequentially increased between the initial configuration and the final configuration. An internal gear pump characterized in that the internal gear pump can be switched from the initial configuration to the final configuration in response to an increase in the rotational speed for rotationally driving the external gear. The internal gear pump according to claim 1, wherein the number of the discharge ports is four or more and is equal to the number of the pump chambers located in the discharge area space.

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