JP2007077916A - Internal gear pump evaluation device and internal gear pump evaluation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal gear pump evaluation device and an internal gear pump evaluation program which can easily evaluate performance of an internal gear pump. <P>SOLUTION: Inner pressure distributions of fluid in a plurality of pump chambers are calculated based on design data of a trochoid gear pump (S11), and a balanced eccentricity ratio ε of a trochoid gear with respect to a casing at a balanced point where a load F with respect to an outer rotor is equal to a bearing force P with respect to the outer rotor (S12 to S17). Where, the load F is generated by pressure of an outer pressure distribution Q(θ) of the fluid in a gap in a radial direction between the outer rotor and a case calculated based on the calculated inner pressure distribution, and the bearing force P is generated by the fluid in the gap in the radial direction between the outer rotor and the case when the outer rotor is rotated with respect to the case. Drive torque M of an inner rotor of the trochoid gear is calculated based on the calculated balanced eccentricity ratio ε (S18). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal gear pump evaluation device and an internal gear pump evaluation program. More specifically, the present invention relates to an internal gear pump evaluation device and an internal gear pump evaluation program suitable for evaluating the performance of the internal gear pump.

  Conventionally, in the design of an internal gear pump, the following experimental evaluation has been performed in order to evaluate the driving torque of the internal gear pump, the hydraulic pressure distribution during driving, and the amount of eccentricity.

  First, experimental jigs such as internal gear pumps and auxiliary equipment are actually manufactured. Next, a measuring instrument such as a pressure sensor or a gap sensor is attached to the experimental jig. In the experiment, various conditions were given to the properties such as the pressure applied to the suction port and the discharge port of the internal gear pump, the rotational speed of the internal gear pump, and the viscosity of the fluid fed by the internal gear pump. Measure data such as gear pump drive torque, pressure distribution during driving, and eccentricity.

Based on the data thus obtained, whether or not the internal gear pump exhibits a predetermined performance has been evaluated (see, for example, Non-Patent Document 1).
Masashi Hattori and three others, “Development of a metal belt type continuously variable transmission for 150 Nm”, Proceedings of the Society of Automotive Engineers, April 2004, Vol. 35, no. 2, p. 141-145

  However, in the above-described experimental evaluation, there is a problem that it takes time and cost to manufacture an experimental jig or perform an experiment. For this reason, it was difficult to evaluate the performance of the internal gear pump.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an internal gear pump evaluation device and an internal gear capable of easily evaluating the performance of the internal gear pump. To provide a pump evaluation program.

  In order to achieve the above object, according to one aspect of the present invention, an internal gear pump evaluation device includes an internal gear composed of an internal gear driven from the outside and an external gear meshing with the internal gear, and A suction port for flowing a fluid into at least one of a plurality of pump chambers that are spaces between the internal gear and the external gear separated by a theoretical meshing portion between the internal gear and the external gear, and a plurality of pump chambers An internal gear pump for evaluating an internal gear pump comprising a housing having a discharge chamber through which fluid is discharged from at least one of a pump chamber into which a fluid flows and a pump chamber different from the pump chamber. Based on the design data, the inner pressure distribution calculation unit that calculates the inner pressure distribution of the fluid in the plurality of pump chambers, and the radial direction of the external gear and the housing based on the inner pressure distribution calculated by the inner pressure distribution calculation unit In the gap A balance point where the load on the external gear due to the pressure of the outer pressure distribution of the body is equal to the bearing force on the external gear generated by the fluid in the radial gap between the external gear and the housing due to the rotation of the external gear relative to the housing The balance eccentricity calculation unit for calculating the balance eccentricity of the internal gear with respect to the housing in the case, and the drive torque of the internal gear of the internal gear based on the balance eccentricity calculated by the balance eccentricity calculation unit And a torque calculation unit for calculating.

  According to this invention, the internal gear pump evaluation device calculates the internal pressure distribution of the fluid in the plurality of pump chambers based on the design data of the internal gear pump, and the external gear and the housing based on the calculated internal pressure distribution. Against the external gear generated by the fluid in the radial gap between the external gear and the housing due to the rotation of the external gear relative to the housing and the load on the external gear due to the pressure of the outer pressure distribution of the fluid in the radial clearance with the body The balance eccentricity of the internal gear with respect to the housing at the balance point at which the bearing force is equal is calculated, and the drive torque of the internal gear of the internal gear is calculated based on the calculated balance eccentricity.

  As a result, an internal gear pump evaluation device capable of easily evaluating the performance of the internal gear pump can be provided.

  Preferably, the balance eccentricity calculation unit includes a flow resistance calculation unit that calculates a flow resistance of the gap between the external gear and the housing, and an inner pressure distribution and flow rate calculated by the inner pressure distribution calculation unit. An outer pressure distribution calculation unit that calculates an outer pressure distribution of the fluid in the gap between the external gear and the housing based on the flow path resistance calculated by the path resistance calculation unit, and an outer side calculated by the outer pressure distribution calculation unit Bearing force equal to the load calculated by the gear force calculation unit when the load is applied to the external gear due to the pressure of the pressure distribution and the housing is a slide bearing and the internal gear is the shaft. An eccentricity calculation unit for calculating the eccentricity and the eccentric direction of the internal gear with respect to the housing corresponding to the state of the oil film of the slide bearing that generates the error, and an error based on the eccentricity calculated by the eccentricity calculation unit in the Nth and subsequent times Is greater than or equal to the specified value In this case, the channel resistance calculation unit, the outer pressure distribution calculation unit, the gear force calculation unit, and the eccentricity calculation unit respectively perform the (N + 1) th channel resistance based on the eccentricity and the eccentric direction of the Nth and subsequent times. An outer pressure distribution, a magnitude and direction of a load on the outer gear due to the pressure of the outer pressure distribution, an eccentricity rate, and a gap width calculation unit for calculating the width of the gap between the outer gear and the housing for calculating the eccentric direction; When the error based on the eccentricity calculated at the Nth or less times by the eccentricity calculating unit is less than a predetermined value, the balanced eccentricity calculating unit uses the Nth eccentricity as the balanced eccentricity.

  According to this invention, the internal gear pump evaluation device calculates the flow resistance of the gap between the external gear and the housing, and based on the inner pressure distribution and flow resistance of the pump chamber, the external gear and the housing The outer pressure distribution of the fluid in the gap is calculated, the load on the external gear due to the pressure of the outer pressure distribution is calculated, and when the housing is a slide bearing and the internal gear is the shaft, the bearing force equal to the load is The eccentricity and the eccentric direction of the internal gear with respect to the housing corresponding to the state of the oil film of the generated sliding bearing are calculated.

  Further, when the error based on the eccentricity calculated at the Nth or less times by the internal gear pump evaluation device is a predetermined value or more, N + 1 based on the eccentricity and the eccentric direction at the Nth or less times, respectively. The flow path resistance, the outer pressure distribution, the magnitude and direction of the load on the outer gear due to the pressure of the outer pressure distribution, the eccentricity, and the width of the gap between the outer gear and the housing for calculating the eccentric direction are calculated. When the error based on the eccentricity calculated in the Nth and subsequent times becomes less than a predetermined value, the Nth eccentricity is set as the balanced eccentricity.

  As a result, the calculation of the inner pressure distribution of the pump chamber is not repeated, so that the performance of the internal gear pump can be evaluated efficiently.

  Preferably, the outer pressure distribution calculating unit provides the two-dimensional thermal analysis finite element method software with parameters in which temperature, heat flux, and specific resistance are replaced with pressure, flow velocity, and flow path resistance, respectively. The pressure distribution of the fluid in the gap between the external gear and the housing is calculated.

  As a result, since it is not necessary to develop new software, the manufacturing cost of the internal gear pump evaluation device can be reduced.

  Preferably, the design data includes the gear shape of the internal gear, the housing shape, the radial gap width between the external gear and the housing, the rotational speed of the internal gear, the pressure between the suction port and the discharge port, and the fluid Includes viscosity.

  Preferably, the inner pressure distribution calculation unit uses the fluid analysis software to determine the pressure distribution of the fluid in the pump chamber based on the suction and discharge pressures, the rotation speed of the internal gear, the viscosity of the fluid, and the gear shape of the internal gear. Is calculated.

  According to another aspect of the present invention, an internal gear pump evaluation program includes an internal gear composed of an externally driven internal gear and an external gear meshing with the internal gear, and the theory of the internal gear and the external gear. A suction port through which fluid flows into at least one of a plurality of pump chambers which are spaces between an internal gear and an external gear separated by a meshing portion, and a pump chamber into which fluid is poured out of the plurality of pump chambers A program for causing a computer to execute a process for evaluating an internal gear pump including a casing having a discharge port through which fluid is discharged from at least one of different pump chambers, the design of the internal gear pump Calculating the inner pressure distribution of the fluid in the plurality of pump chambers based on the data, and the pressure of the outer pressure distribution of the fluid in the radial gap between the external gear and the housing based on the calculated inner pressure distribution The internal gear with respect to the housing at the balance point where the load on the external gear by the motor and the bearing force against the external gear generated by the fluid in the radial gap between the external gear and the housing due to the rotation of the external gear with respect to the housing are equal And calculating a drive eccentricity of the internal gear of the internal gear based on the calculated balance eccentricity.

  According to this invention, the internal gear pump evaluation program calculates the internal pressure distribution of the fluid in the plurality of pump chambers based on the design data of the internal gear pump, and the external gear and the housing based on the calculated internal pressure distribution. Against the external gear generated by the fluid in the radial gap between the external gear and the housing due to the rotation of the external gear relative to the housing and the load on the external gear due to the pressure of the outer pressure distribution of the fluid in the radial clearance with the body The balance eccentricity of the internal gear with respect to the housing at the balance point at which the bearing force is equal is calculated, and the drive torque of the internal gear of the internal gear is calculated based on the calculated balance eccentricity.

  As a result, an internal gear pump evaluation program capable of easily evaluating the performance of the internal gear pump can be provided.

  Preferably, the step of calculating the balance eccentricity includes the step of calculating the flow resistance of the gap between the external gear and the housing, the calculated inner pressure distribution of the pump chamber, and the calculated flow resistance. On the basis of the step of calculating the outer pressure distribution of the fluid in the gap between the outer gear and the casing, the step of calculating the load on the outer gear due to the pressure of the calculated outer pressure distribution, the casing as a slide bearing, Calculating the eccentricity and the eccentric direction of the internal gear with respect to the housing corresponding to the state of the oil film of the sliding bearing that generates a bearing force equal to the calculated load when the connected gear is used as an axis, and the Nth and subsequent times When the error based on the eccentricity calculated at the time is equal to or greater than a predetermined value, the N + 1th channel resistance, the outer pressure distribution, and the outer pressure distribution, respectively, based on the eccentricity and the eccentric direction of the Nth and subsequent times To the pressure of The step of calculating the magnitude and direction of the load on the external gear, the eccentricity, and the width of the gap between the external gear and the housing for calculating the eccentric direction, and the eccentricity calculated in the Nth and subsequent times When the error based on becomes less than a predetermined value, the step of setting the Nth eccentricity as the balanced eccentricity is included.

  According to this invention, the flow resistance of the gap between the external gear and the casing is calculated by the internal gear pump evaluation program, and the external gear and the casing are calculated based on the inner pressure distribution of the pump chamber and the flow resistance. The outer pressure distribution of the fluid in the gap is calculated, the load on the external gear due to the pressure of the outer pressure distribution is calculated, and when the housing is a slide bearing and the internal gear is the shaft, the bearing force equal to the load is The eccentricity and the eccentric direction of the internal gear with respect to the housing corresponding to the state of the oil film of the generated sliding bearing are calculated.

  Further, when the error based on the eccentricity calculated in the Nth or less times by the internal gear pump evaluation program is equal to or greater than a predetermined value, N + 1 is determined based on the eccentricity and the eccentric direction of the Nth or less times, respectively. The flow path resistance, the outer pressure distribution, the magnitude and direction of the load on the outer gear due to the pressure of the outer pressure distribution, the eccentricity, and the width of the gap between the outer gear and the housing for calculating the eccentric direction are calculated. When the error based on the eccentricity calculated in the Nth and subsequent times becomes less than a predetermined value, the Nth eccentricity is set as the balanced eccentricity.

  As a result, the calculation of the inner pressure distribution of the pump chamber is not repeated, so that the performance of the internal gear pump can be evaluated efficiently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol in the figure shows the same or equivalent member, and the overlapping description is not repeated.

  FIG. 1 is a perspective view showing a configuration of a trochoid pump 1 to be evaluated in the present embodiment. Referring to FIG. 1, trochoid pump 1 includes a trochoid gear including inner rotor 2 and outer rotor 3, and cases 4 and 5.

  The case 5 is machined with eyebrows-type intake and discharge ports and a round hole through which a drive shaft for driving the inner rotor 2 passes. A boss hole into which the drive shaft is fitted is machined in the inner rotor 2.

  And the trochoid pump 1 is assembled by setting the inner rotor 2 and the outer rotor 3 in the case 5 and fastening the case 4 to the case 5. An oil seal is attached to the round hole of the case 5, and the shaft is fitted into the boss hole of the inner rotor 2 from the outside of the case 5.

  Further, a suction pipe and a discharge pipe are attached to the suction port and the discharge port, respectively. Note that the suction pipe and the discharge pipe may be formed integrally with the case 5.

  In the present embodiment, each space between the inner rotor 2 and the outer rotor 3 divided by a theoretical meshing portion between the inner rotor 2 and the outer rotor 3 is referred to as a pump chamber. The theoretical meshing portion is obtained by calculation from the shapes of the inner rotor 2 and the outer rotor 3. Even if the inner rotor 2 and the outer rotor 3 are not actually meshed with each other at the theoretical meshing portion, the pump chamber is divided by the theoretical meshing portion. When the inner rotor 2 rotates by being driven by the drive shaft, the outer rotor 3 rotates by meshing with the inner rotor 2.

  As the inner rotor 2 and the outer rotor 3 rotate, the volumes of the plurality of pump chambers change. In the process of increasing the volume of the pump chamber, fluid such as oil is sucked into the pump chamber from the suction port, and in the process of decreasing the volume of the pump chamber, the fluid is discharged from the pump chamber to the discharge port.

  Thus, when the trochoid pump 1 is driven, fluid is sucked from the suction port and fluid is discharged from the discharge port.

  For example, in the case of an automobile, the trochoid pump 1 is an oil pump for engine lubrication, an oil pump for AT (Automatic Transmission), a CVT (Continuously Variable Transmission) oil pump, or diesel fuel. Used as a supply pump.

  FIG. 2 is a perspective view showing the fluid flow path modeled by the trochoid pump 1 in the present embodiment. Referring to FIG. 2, the middle wavy solid indicates the outer shape of the fluid in the pump chamber of trochoid pump 1. When the trochoid pump 1 is driven, this undulating solid rotates around the drive axis.

  In addition, two solid bodies shaped like a hollow cylinder cut out in front of a corrugated solid body are the outline of the fluid from the suction line to the suction port and the fluid shape from the discharge port to the discharge line, respectively. The outline is shown.

  In the internal gear pump such as the trochoid pump 1, the case 4 is arranged so that the pressure on the side opposite to the side where the suction port and the discharge port of the internal gear are located is the same as the side where the suction port and the discharge port are located. , 5 are often provided with pressure guiding lines so that the internal gear is centered in the direction of the drive shaft in the case.

  For this reason, in FIG. 2, it is set as the model in which the fluid similar to the near side exists also on the other side of a wave-like solid. As a result, the inner rotor 2 and the outer rotor 3 can be modeled on the assumption that the same pressure is applied to the side surfaces on both sides in the rotation axis direction.

  FIG. 3 is a diagram showing the relationship between the outer periphery of the trochoidal gear and the inner periphery of the case 5 in the present embodiment. Referring to FIG. 3, in the present embodiment, the relationship between the trochoid gear formed of inner rotor 2 and outer rotor 3 and case 5 is the relationship between the shaft of the journal bearing and the bearing.

  In a journal bearing, when a shaft rotates with a bearing lubricated with oil, an oil film is formed between the bearing and the shaft. The narrow portion of the wedge-shaped oil film between the bearing and the shaft becomes a high pressure region according to the rotation of the shaft. For this reason, a bearing force P for lifting the shaft is generated in the high pressure region.

  Similarly, since the oil sent out by the trochoid pump 1 is filled in the gap between the case and the trochoid gear from the gap between the side surface of the trochoid gear and the case, when the trochoid gear is driven to rotate, the case and the trochoid gear are rotated. An oil film is formed between the gears. Further, the trochoid gear rotates eccentrically with respect to the case.

  For this reason, when the trochoid gear rotates counterclockwise, the wedge-shaped oil film causes the bearing to move in the direction from the position closest to the case and the trochoid gear toward the rotation center of the trochoid gear clockwise from ψ °. A force P is generated.

  FIG. 4 is a graph showing the relationship between the pressure and angle of the oil film between the trochoid gear and the case in the present embodiment. Referring to FIG. 4, when the width of the gap between the outer periphery of the trochoid gear and the inner periphery of the case when the trochoid gear is at the center of the case is C, and the amount of eccentricity of the trochoid gear with respect to the case is e, the eccentricity ε = e / C.

  The graph shown in FIG. 4 shows the relationship between the pressure and angle of the oil film between the trochoid gear and the case with respect to the eccentricity ε = 0.5, 0.75, 0.9. The plots for the eccentricity ε = 0.5, 0.75, 0.9 are indicated by □, ◇, and Δ, respectively.

  Here, in FIG. 3, the pressure at the counterclockwise angle when the 12 o'clock direction from the rotation center of the trochoidal gear is 0 ° is shown. At this time, the closest position between the trochoid gear and the case is 180 °.

As shown in FIG. 4, at any eccentricity ε, the pressure is highest at a position of 120 ° to 180 °. Based on the result shown in this graph, an equation of the bearing force angle ψ = −35.893 × ε ² −35.788 × ε + 89.97 from the closest position is calculated.

  FIG. 5 is a block diagram showing an outline of the configuration of the trochoid gear pump evaluation device 10 in the present embodiment. Referring to FIG. 5, trochoid gear pump evaluation apparatus 10 is configured by a general-purpose computer such as a personal computer or a workstation.

  The trochoid gear pump evaluation device 10 includes a control unit 11 for controlling the entire trochoid gear pump evaluation device 10, a storage unit 12 for storing predetermined information, and predetermined information in the trochoid gear pump evaluation device 10. An input unit 13 for inputting, an output unit 14 for outputting predetermined information from the trochoid gear pump evaluation device 10, and information recorded in the recording medium 17 are input, or necessary information is stored in the recording medium 17. An external storage device 15 for recording and a communication unit 16 for communicating with an external computer via the network 20 are included.

  The control unit 11 includes an MPU (Micro Processing Unit) and an auxiliary circuit of the MPU, and controls the storage unit 12, the input unit 13, the output unit 14, the external storage device 15, and the communication unit 16, and stores them in the storage unit 12. A predetermined process is executed in accordance with the program or data thus processed, the data input from the input unit 13, the external storage device 15, or the communication unit 16 is processed, and the processed data is stored in the storage unit 12. To the output unit 14, the external storage device 15, or the communication unit 16.

  The storage unit 12 includes a RAM (Random Access Memory) used as a work area necessary for executing the program by the control unit 11 and a ROM (Read Only Memory) for storing a program to be executed by the control unit 11. Including. In addition, a program for executing a predetermined process is read from the external storage device 15 and the communication unit 16 and stored in the RAM. Further, a magnetic disk storage device such as a hard disk drive (hereinafter referred to as “HDD (Hard Disk Drive)”) of the external storage device 15 is used as an auxiliary storage device for assisting the storage area of the RAM.

  The input unit 13 is an interface for inputting signals from a keyboard, a mouse, a touch panel, and the like, and can input necessary information to the trochoid gear pump evaluation device 10.

  The output unit 14 is an interface for outputting a signal to a display such as a liquid crystal display (LCD) or a speaker and a speaker, and can output necessary information from the trochoid gear pump evaluation device 10.

  The external storage device 15 reads a program or data recorded on the recording medium 17 and transmits it to the control unit 11. Further, the external storage device 15 writes necessary data to the recording medium 17 in accordance with an instruction from the control unit 11.

  The computer-readable recording medium 17 includes a magnetic tape, a cassette tape, a floppy (registered trademark) disk, a magnetic disk such as a hard disk, an optical disk such as a CD-ROM (Compact Disk Read Only Memory) and a DVD (Digital Versatile Disk), an MO (Magneto Optical disk), MD (MiniDisc) and other magneto-optical disks, IC cards, memory cards such as optical cards, mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrionally Erasable and Programmable Read Only Memory) A recording medium that carries a fixed program including a semiconductor memory such as a flash ROM.

  The communication unit 16 is connected to a wired or wireless network 20 and communicates with other computers connected to the network 20. The communication unit 16 is controlled by the control unit 11 and transmits predetermined information to another computer or receives information from another computer.

  FIG. 6 is a flowchart showing the flow of the trochoid gear pump evaluation process in the present embodiment. This trochoid gear pump evaluation process is a process executed by the trochoid gear pump evaluation apparatus 10.

  With reference to FIG. 6, first, in step S11, the control unit 11 of the trochoid gear pump evaluation apparatus 10 calculates the pressure distribution in the pump chamber inside the trochoid gear. Here, the pressure distribution inside the trochoidal gear is calculated by fluid analysis software using a method of handling a theoretical boundary called a VOF (Volume of Fluid) method based on the finite volume method.

  The data input to the fluid analysis software is data input in advance from the input unit 13 or the communication unit 16 and stored in the storage unit 12 or the external storage device 15, and includes the suction port pressure, the discharge port pressure, and the trochoidal gear. The rotational speed, the viscosity of the fluid, and the shape of the trochoidal gear.

  For example, CWHirt et al., “Volume of fluid (VOF) Method for the Dynamics of Free Boundaries”, Journal of Computational Physics, 39 (1981). ), P.M. 201.

  A method for automatically modeling a liquid phase boundary by automatic element subdivision is described in, for example, CDAJ news, vol. 38 (2004), p. 24 and http://www.cd-adapco.com/news/19/gerotor.htm.

  FIG. 7 is a diagram showing the pressure distribution in the pump chamber of the trochoid pump 1 in the present embodiment. In FIG. 7, a portion where the hatching density is high is a portion where the pressure is high, and a portion where the hatching density is low is a portion where the pressure is low.

  Referring to FIG. 7, the pressure distribution shown in this figure is obtained by the calculation in step S11. The pressure in the pump chamber communicating with the suction port on the right side of FIG. 7 is equal to that of the suction port. The pressure in the pump chamber communicating with the discharge port on the left side of FIG. 7 is equal to that of the discharge port. The pressure at the discharge port is higher than the pressure at the suction port.

  The pressure in the pump chamber that is moving away from the upper suction port in FIG. 7 is higher than the pressure in the pump chamber that communicates with the suction port, and is lower than the pressure in the pump chamber that communicates with the discharge port. .

  The pressure of the pump chamber just communicated with the lower suction port in FIG. 7 is lower than the pressure of other pump chambers communicating with the suction port.

Returning to FIG. 6, in step S <b> 12, the control unit 11 calculates the flow path resistance of the gap between the trochoidal gear and the case. Here, the width of the gap between the outer periphery of the trochoid gear and the inner periphery of the case when the trochoid gear is at the center of the case is C as described above. The provisional eccentricity is ε _N ′ (initial value ε ₁ ′ = 0), and the eccentric direction is φ _N (initial value φ ₁ = 0). N is the number of times the convergence step is repeated in the relaxation method.

At this time, the gap width d _{N at the} counterclockwise angle θ when the 12 o'clock direction from the rotation center of the trochoidal gear is 0 ° is expressed by Expression (1).

Further, the flow path resistance ρ _{N at the} angle θ is expressed by Expression (2) using d _N calculated by Expression (1).

  Next, in step S13, the control unit 11 uses the pressure distribution in the pump chamber calculated in step S11 as a boundary condition, and the flow path resistance, the rotation speed of the trochoid gear, the viscosity of the fluid, and the shape of the trochoid gear calculated in step S12. Based on the shape data of the cases 4 and 5, the pressure distribution Q (θ) of the gap between the trochoid gear outside the trochoid gear and the case is calculated.

  Here, parameters for the two-dimensional thermal analysis finite element method software, temperature, heat flux, and specific resistance are replaced with pressure, flow velocity, and flow resistance, respectively, and the rotational speed of the trochoidal gear. , Fluid viscosity, trochoid gear shape, and case 4 and 5 shape data are given to the finite element method software for two-dimensional thermal analysis to calculate the pressure distribution Q (θ) outside the trochoid gear Is done.

  The rotational speed of the trochoid gear, the viscosity of the fluid, the shape of the trochoid gear, and the data of the shapes of the cases 4 and 5 are input in advance from the input unit 13 or the communication unit 16, and are stored in the storage unit 12 or the external storage device 15. Is remembered.

  FIG. 8 is a diagram showing the pressure distribution in the gap between the trochoid gear of the trochoid pump 1 and the case in the present embodiment. In FIG. 8, the portion where the hatching density is high is the portion where the pressure is high, and the portion where the hatching density is low is the portion where the pressure is low.

  Referring to FIG. 8, the pressure distribution shown in this figure is obtained by the calculation in step S13. The pressure on the left side of FIG. 8 is higher than the pressure on the right side of FIG. Further, the pressure gradually decreases in the transition portion from the high pressure portion to the low pressure portion.

  Returning to FIG. 6, in step S <b> 14, the control unit 11 calculates the load F exerted on the trochoid gear by the pressure of the pressure distribution Q (θ) outside the trochoid gear calculated in step S <b> 13. Here, since the component of Q (θ) can be decomposed into the x-axis direction and the y-axis direction, it can be expressed as in equation (3).

Then, as shown in equations (4) and (5), when a component obtained by multiplying the x-axis direction component and the y-axis direction component of Q (θ) by a minute area is integrated with respect to θ as shown in FIG. In each case, an x-axis direction component F _x and a y-direction component F _{y of} the load F _N are obtained. Further, load direction tau _N load F _N is represented by the formula (6).

Then, in step S15, the control unit 11 calculates the bearing force P _N to balance the load F _N. That is, the bearing force P _N is calculated as bearing force P _N = | F _N |.

Next, in step S <b> 16, the control unit 11 first calculates an eccentricity ε _{N at} which the bearing force P _N is generated and stores it in the storage unit 12. The eccentricity ε _N is calculated by equation (7). Here, μ is the viscosity of the fluid, U is the peripheral speed of the outer surface of the trochoid gear, D is the diameter of the outer surface of the trochoid gear, and H is the tooth width of the trochoid gear.

Then, the control unit 11 calculates the eccentric direction φ _N by substituting the calculated eccentricity ε _N into the equation (8).

Next, in step S17, the control unit 11 determines whether or not the eccentricity has converged. Here, the error e _N is calculated by the equation (9), and when the error e _N <allowable value (for example, an appropriate value of 0 to 0.01), the control unit 11 converges the eccentricity rate. Judge.

When it is determined that the eccentricity has not converged (NO in step S17), the control unit 11 calculates the temporary eccentricity ε ′ _{N + 1} using equation (10). Here, α is a relaxation coefficient in the relaxation method. And the control part 11 adds 1 to N, and returns the process to perform to step S12.

  On the other hand, if it is determined that the eccentricity has converged (YES in step S17), the control unit 11 advances the process to be executed to step S18.

In step S18, the control unit 11 calculates the drive torque M by substituting the eccentricity ε _N calculated in step S17 into the equation (11). Then, the calculated drive torque M and the eccentricity ε _N calculated in step S17 are output to the display of the output unit 14, the hard disk of the external storage device 15, or the like. Thereafter, the control unit 11 ends the trochoid gear pump evaluation process.

  FIG. 9 is a diagram for explaining how to obtain an angle in the comparison between the calculation of the pressure distribution and the actual measurement value in the present embodiment. Referring to FIG. 9, the counterclockwise angle with respect to the 12 o'clock direction from the center of rotation of the trochoidal gear is θ.

  FIG. 10 is a graph showing a comparison result between the calculation of the pressure distribution and the actual measurement value in the present embodiment. Referring to FIG. 10, the points plotted with ◇ are when the pressure of the gap between the trochoidal gear and the case is measured with a pressure sensor when the rotational speed of the drive shaft is 500 rpm in the trochoid pump of the experimental jig. The measured value of the pressure is shown.

  In addition, the graph drawn with a solid line shows the eccentricity when the rotational speed of the drive shaft is 500 rpm in the trochoid gear pump evaluation process described in FIG. The calculation result of the pressure distribution of the clearance gap between the trochoid gear and a case when (epsilon) converges is shown.

  As shown in FIG. 10, at θ = 60 °, the actually measured value is 0.83 MPa, and the calculation result is 0.82 MPa. Further, at θ = 330 °, the actually measured value is 0.33 MPa, and the calculation result is 0.29 MPa. Thus, it can be said that the actual measurement value and the calculation result are substantially matched.

As described above, in the present embodiment, the load F _N to the trochoid gear due to the pressure of the fluid pressure distribution Q (θ) in the radial gap between the trochoid gear and the case based on the pressure in the pump chamber, and the case The eccentricity ε _N of the trochoid gear with respect to the case when the bearing force P _N against the trochoid gear generated by the fluid in the radial gap between the trochoid gear and the case due to the rotation of the trochoid gear is equally balanced The drive torque M of the internal gear of the trochoid gear is calculated on the basis of the eccentricity ε _N that has been set.

Therefore, it is possible to easily evaluate the performance of the trochoidal gear pump such as the driving torque M, the fluid pressure distribution Q (θ), the eccentricity ε _N and the force applied to each part.

  In addition, using the calculation result of the pressure distribution of the main flow path in the trochoid gear by the fluid analysis in step S11, in step S12 and step S13, the pressure distribution Q (θ of the gap between the very narrow case and the trochoid gear is calculated. ) Was calculated.

  The pressure distribution Q (θ) in the gap between the case and the trochoid gear is particularly affected by the eccentricity of the trochoid gear. On the other hand, the pressure distribution in the trochoid gear is not significantly affected by the eccentricity of the trochoid gear. Further, the calculation of the pressure distribution in the trochoid gear takes a relatively long time, and the calculation of the pressure distribution Q (θ) in the gap between the case and the trochoid gear does not take much time.

  Therefore, even if the eccentricity ε is updated in step S17, it is not necessary to repeat the calculation of the pressure distribution in the trochoidal gear, and it is only necessary to repeat the calculation of the pressure distribution Q (θ) in the gap between the case and the trochoidal gear. Therefore, the convergence calculation of the eccentricity ε can be efficiently performed.

  In addition, since the volume of the inside of the trochoid gear and the gap between the case and the trochoid gear are significantly different, the number of meshes at the time of element division is extremely different. In the present embodiment, the inside of the trochoid gear and the gap between the case and the trochoid gear are calculated by dividing them into two systems, so that the influence of the portion having a remarkably small volume can be sufficiently reflected.

  In addition, the pressure distribution Q (θ) of the gap between the case and the trochoid gear is calculated in consideration of the change in the gap width between the case and the trochoid gear due to the eccentricity of the trochoid gear. can do.

  In this embodiment, the relaxation method is used as the convergence calculation method. However, the present invention is not limited to this, and other convergence calculation methods such as Newton's method can be used as long as the eccentricity ε can be converged. You may do it.

  In the present embodiment, the evaluation of the trochoid type internal gear pump has been described. However, the present invention is not limited to this, and any other internal gear pump may be used as long as it is a pump that sends fluid by the external gear and the internal gear of the internal gear. For example, an involute type or cycloid type internal gear pump in which gears are formed by an involute curve or a cycloid curve may be used, or a crescent gear having two or more external gear teeth than the internal gear teeth is used. It may be an internal gear pump.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a perspective view which shows the structure of the trochoid pump evaluated in this Embodiment. It is a perspective view which shows the flow path of the fluid which the trochoid pump in this Embodiment modeled. It is a figure which shows the relationship between the outer periphery of the trochoid gear in this Embodiment, and the inner periphery of a case. It is a graph which shows the relationship between the pressure of an oil film between a trochoid gearwheel and a case in this Embodiment, and an angle. It is a block diagram which shows the outline of a structure of the trochoid gear pump evaluation apparatus in this Embodiment. It is a flowchart which shows the flow of the trochoid gear pump evaluation process in this Embodiment. It is a figure which shows the pressure distribution of the pump chamber of the trochoid pump in this Embodiment. It is a figure which shows the pressure distribution of the clearance gap between the trochoid gearwheel and case of the trochoid pump in this Embodiment. It is a figure for demonstrating how to take the angle in the comparison of the calculation of the pressure distribution in this Embodiment, and a measured value. It is a graph which shows the comparison result of the calculation of pressure distribution in this Embodiment, and an actual measurement value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Trochoid pump, 2 inner rotor, 3 outer rotor, 4, 5 case, 10 trochoid gear pump evaluation apparatus, 11 control part, 12 memory | storage part, 13 input part, 14 output part, 15 external storage device, 16 communication part, 17 recording medium 20 network.

Claims (7)

An internal gear composed of an internal gear driven from the outside and an external gear meshing with the internal gear, and the internal gear and the external gear separated by a theoretical meshing portion between the internal gear and the external gear From at least one of the suction port through which fluid flows into at least one of the plurality of pump chambers that are spaces between the pump chamber and the pump chamber different from the pump chamber into which the fluid flows into among the plurality of pump chambers An internal gear pump evaluation device for evaluating an internal gear pump composed of a housing having a discharge port through which fluid is discharged,
An inner pressure distribution calculating means for calculating an inner pressure distribution of the fluid in the plurality of pump chambers based on design data of the internal gear pump;
The load on the external gear due to the pressure of the outer pressure distribution of the fluid in the radial gap between the outer gear and the housing based on the inner pressure distribution calculated by the inner pressure distribution calculating means, and the The balance eccentricity ratio of the internal gear with respect to the housing at a balance point at which the bearing force against the external gear generated by the fluid in the radial gap between the external gear and the housing due to the rotation of the external gear becomes equal. A balanced eccentricity calculating means for calculating
An internal gear pump evaluation device comprising: torque calculation means for calculating a drive torque of the internal gear of the internal gear based on the balance eccentricity calculated by the balance eccentricity calculation means. The balance eccentricity calculating means is:
Channel resistance calculation means for calculating channel resistance of the gap between the external gear and the housing;
Based on the inner pressure distribution of the pump chamber calculated by the inner pressure distribution calculating means and the flow path resistance calculated by the flow path resistance calculating means, the fluid in the gap between the external gear and the housing An outer pressure distribution calculating means for calculating an outer pressure distribution;
Counter gear force calculating means for calculating a load on the external gear by the pressure of the outer pressure distribution calculated by the outer pressure distribution calculating means;
The case corresponding to the state of the oil film of the slide bearing that generates a bearing force equal to the load calculated by the gear force calculation means when the case is a slide bearing and the internal gear is an axis. An eccentricity calculating means for calculating an eccentricity rate and an eccentric direction of the internal gear with respect to
When the error based on the eccentricity calculated at the Nth or less times by the eccentricity calculating means is a predetermined value or more, the flow path resistance calculating means based on the eccentricity and the eccentric direction of the Nth or less times, By the outer pressure distribution calculating means, the gear force calculating means, and the eccentricity calculating means, the flow resistance of the N + 1th passage, the outer pressure distribution, and the load on the outer gear due to the pressure of the outer pressure distribution, respectively. A gap width calculating means for calculating a width of the gap between the external gear and the housing for calculating the size and direction, the eccentricity, and the eccentric direction;
When the error based on the eccentricity calculated by the eccentricity calculation means in the Nth or less times becomes less than a predetermined value, a balanced eccentricity calculation means that uses the Nth eccentricity as the balance eccentricity; The internal gear pump evaluation device according to claim 1, comprising:   The outer pressure distribution calculating means provides the two-dimensional thermal analysis finite element method software with parameters obtained by replacing temperature, heat flux, and resistivity with pressure, flow velocity, and channel resistance, respectively. The internal gear pump evaluation device according to claim 2, wherein a pressure distribution of the fluid in a gap between the external gear and the housing is calculated.   The design data includes the gear shape of the internal gear, the housing shape, the gap width in the radial direction between the external gear and the housing, the rotational speed of the internal gear, the pressure at the suction port and the discharge port, And the internal gear pump evaluation apparatus of Claim 1 containing the viscosity of the said fluid.   The inner pressure distribution calculating means is configured to calculate the pressure in the pump chamber based on the pressure of the suction port and the discharge port, the rotational speed of the internal gear, the viscosity of the fluid, and the shape of the gear of the internal gear. The internal gear pump evaluation device according to claim 1, wherein a pressure distribution of the fluid is calculated. An internal gear composed of an internal gear driven from the outside and an external gear meshing with the internal gear, and the internal gear and the external gear separated by a theoretical meshing portion between the internal gear and the external gear From at least one of the suction port through which fluid flows into at least one of the plurality of pump chambers that are spaces between the pump chamber and the pump chamber different from the pump chamber into which the fluid flows into among the plurality of pump chambers An internal gear pump evaluation program for causing a computer to execute a process of evaluating an internal gear pump composed of a housing having a discharge port through which fluid is discharged,
Calculating an internal pressure distribution of the fluid in the plurality of pump chambers based on design data of the internal gear pump;
The load on the external gear due to the pressure of the external pressure distribution of the fluid in the radial gap between the external gear and the housing based on the calculated internal pressure distribution, and the rotation of the external gear with respect to the housing Calculating a balance eccentricity ratio of the internal gear with respect to the housing at a balance point at which a bearing force against the external gear generated by a fluid in a radial gap between the external gear and the housing is equal;
An internal gear pump evaluation program for causing a computer to execute a step of calculating a driving torque of the internal gear of the internal gear based on the calculated balance eccentricity. The step of calculating the balance eccentricity includes:
Calculating a flow path resistance of a gap between the external gear and the housing;
Calculating an outer pressure distribution of the fluid in a gap between the outer gear and the housing based on the calculated inner pressure distribution of the pump chamber and the calculated flow path resistance;
Calculating a load on the external gear by the pressure of the calculated outer pressure distribution;
When the housing is a sliding bearing and the internal gear is an axis, the internal gear with respect to the housing corresponding to the state of the oil film of the sliding bearing that generates a bearing force equal to the calculated load is used. Calculating an eccentricity rate and an eccentric direction;
When the error based on the eccentricity calculated in the Nth time or less is a predetermined value or more, based on the eccentricity and the eccentric direction in the Nth time or less, the N + 1th flow path resistance and the outer side, respectively. Calculating the pressure distribution, the magnitude and direction of the load on the external gear due to the pressure of the outer pressure distribution, the eccentricity, and the width of the gap between the external gear and the housing for calculating the eccentric direction. When,
The method according to claim 6, further comprising the step of setting the Nth eccentricity as the balance eccentricity when an error based on the eccentricity calculated in the Nth or less times is less than a predetermined value. Contacted gear pump evaluation program.

Images