JP2017005962A - Variable throttle system and variable throttle type fluid bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable throttle system capable of further improving responsiveness, and a variable throttle type fluid bearing with the variable throttle system.SOLUTION: A variable throttle system 2 supplies a fluid of which the flow rate is adjusted to a fluid bearing and floats a born member from a bearing member just by a bearing clearance distance H. The variable throttle system comprises: variable throttle means 30 including an electric actuator 33 to which the pumped fluid is supplied, and which supplies a fluid Q at an adjusted flow rate to the fluid bearing and adjusts the flow rate of the fluid; a drive circuit 42 which drives the electric actuator; and control means 41 which controls the electric actuator via the drive circuit. The control means calculates a predictive bearing clearance distance that is a predicted bearing clearance distance, based on a control state of the electric actuator without detecting an actual distance of the bearing clearance distance, and performs feedback control on the electric actuator in such a manner that the calculated predictive bearing clearance distance becomes a target distance.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a variable throttle system and a variable throttle fluid bearing provided with the variable throttle system.

  For example, Patent Literature 1 discloses a variable throttle type hydrostatic bearing provided with a diaphragm type variable throttle. The diaphragm type variable aperture described in Patent Document 1 deforms the diaphragm using the pressure of the fluid that fluctuates in accordance with the bearing clearance distance that is the flying height of the table that is a movable body, and between the diaphragm and the fluid flow path. A variable aperture is configured by making the aperture gap distance, which is the gap between the apertures, variable. And the convex part is attached to the center part of the diaphragm, and the recessed part which accommodates a convex part is provided in the housing of a variable diaphragm so that a convex part can slide according to a deformation | transformation of a diaphragm. The convex portion of the diaphragm and the concave portion of the housing constitute a damper having a large damping property, and vibration of the diaphragm is suppressed.

JP 2014-231857 A

  The variable-throttle hydrostatic bearing described in Patent Document 1 has a diaphragm and a fluid flow path after the pressure of the fluid in the pocket fluctuates after the bearing gap distance fluctuates and the pressure of the fluid in the pocket fluctuates. After the pressure of the fluid in the throttle gap between the two changes, and the pressure of the fluid in the throttle gap fluctuates, the diaphragm deforms. Then, after the diaphragm is deformed and the aperture gap distance is changed, the flow rate of the fluid is adjusted. In addition, even if a fluid whose flow rate is adjusted is supplied to the pocket, the flying height of the movable body having a very large mass will change, so the actual bearing gap distance does not change instantaneously, and a certain amount of delay occurs. After the time has elapsed, the bearing clearance distance changes. That is, the variable throttle hydrostatic bearing described in Patent Document 1 has low responsiveness. Moreover, since the variable-throttle hydrostatic bearing described in Patent Document 1 also includes a vibration suppression damper in the diaphragm, the load during deformation of the diaphragm may increase, and the responsiveness may be further reduced.

  The present invention has been made in view of such a point, and it is an object of the present invention to provide a variable throttle system that can further improve responsiveness, and a variable throttle fluid bearing having the variable throttle system. To do.

  In order to solve the above problems, a variable throttle system and a variable throttle fluid bearing according to the present invention take the following means. First, a first aspect of the present invention is a variable throttle that adjusts the flow rate of a fluid that has been pumped and supplies the fluid whose flow rate has been adjusted to a fluid bearing, so that the bearing member is lifted from the bearing member by a bearing clearance distance. A variable throttling means having an electric actuator for supplying a fluid whose pressure has been fed and adjusting a flow rate to the fluid bearing and adjusting the flow rate of the fluid, and a drive for driving the electric actuator A circuit and control means for controlling the electric actuator via the drive circuit. Then, the control means calculates a predicted bearing gap distance that is a predicted bearing gap distance based on a control state of the electric actuator without detecting an actual distance of the bearing gap distance, and calculates the calculated prediction. The electric actuator is feedback-controlled so that the bearing gap distance becomes the target distance.

  Next, the second invention of the present invention is a variable that adjusts the flow rate of the fluid that has been pumped and supplies the fluid whose flow rate has been adjusted to the fluid bearing so that the bearing member floats from the bearing member by the bearing clearance distance. A throttling system, which is supplied with a pressure-fed fluid, supplies a fluid whose flow rate is adjusted to the fluid bearing, and variable throttle means including an electric actuator for adjusting the flow rate of the fluid, and drives the electric actuator A drive circuit; control means for controlling the electric actuator via the drive circuit; and storage means. The variable restricting means is disposed at a position facing a discharge flow path for discharging a fluid supplied to the fluid bearing and an opening serving as an inlet of the fluid to the discharge flow path, and is flexibly deformed to thereby form the opening. A diaphragm formed between the diaphragm and the electric actuator for flexibly deforming the diaphragm based on a control signal from the control means, and the storage means includes the diaphragm The deflection amount / bearing gap distance characteristic indicating the bearing gap distance with respect to the deflection amount and the electrical characteristics of the electric actuator are stored. The control means includes the electrical characteristics stored in the storage means, and an applied voltage that is a voltage applied to the electric actuator measured using a voltage detection means provided in the drive circuit. An estimated deflection amount that is an estimated deflection amount of the diaphragm is calculated based on a supply current that is a current supplied to the electric actuator measured using a current detection unit provided in the drive circuit. Alternatively, the actual deflection amount, which is the actual deflection amount of the diaphragm, is detected using a deflection amount detection unit provided in the diaphragm, and the estimated deflection amount or the actual deflection amount is stored in the storage unit. Based on the deflection amount / bearing gap distance characteristics, a predicted bearing gap distance that is a predicted bearing gap distance is calculated, and the calculated prediction受隙 distance between, so that the target distance, a feedback control of the said electric actuator.

  Next, a third invention of the present invention is the variable aperture system according to the second invention, wherein the electrical characteristics stored in the storage means are a resistance value of the electric actuator and the electric motor. The inductance of the actuator.

  Next, a fourth invention of the present invention is the variable aperture system according to the third invention, wherein the control means calculates the estimated deflection amount when the applied voltage, the resistance value, and the resistance value are calculated. Based on the voltage based on the supply current, the voltage based on the inductance and the supply current, and the induced electromotive force of the electric actuator based on the movement amount of the diaphragm according to the deflection amount of the diaphragm, Calculate the estimated deflection.

  Next, according to a fifth aspect of the present invention, there is provided a variable throttle system according to any one of the first to fourth inventions, wherein a fluid whose flow rate is adjusted is supplied to the fluid bearing, and the variable throttle system. And a fluid pumping means for pumping fluid to the variable throttle type fluid bearing.

  According to the first aspect of the invention, feedback control is performed using the predicted bearing gap distance instead of the actual bearing gap distance in which a certain delay time is generated before the change occurs due to low responsiveness. Even if the flow rate of the fluid is adjusted by controlling the electric actuator, if the mass of the bearing member (movable body) is very large, the actual bearing gap distance changes after a certain delay time has elapsed. However, the predicted bearing clearance distance is not an actual bearing clearance distance but a distance calculated by the control means based on the control state of the electric actuator (a distance calculated by so-called simulation). That is, the predicted bearing gap distance can be changed without causing a delay time after the electric actuator is controlled to adjust the flow rate of the fluid. Therefore, it is possible to realize a variable aperture system that can further improve the responsiveness.

  According to the second invention, similar to the first invention, feedback is performed using the predicted bearing gap distance instead of the actual bearing gap distance in which a certain delay time is generated until the change occurs due to low responsiveness. Control. Also, calculate the predicted bearing clearance distance based on the estimated deflection amount that is the estimated deflection amount of the diaphragm, or the actual deflection amount that is the actual deflection amount of the diaphragm, and the deflection amount / bearing gap distance characteristics. Thus, the predicted bearing clearance distance can be calculated appropriately without causing a delay time. Therefore, it is possible to realize a variable aperture system that can further improve the responsiveness.

  According to the third aspect of the invention, since the estimated deflection amount of the diaphragm is calculated based on the resistance value and inductance of the electric actuator, the voltage applied to the electric actuator, and the supply current to the electric actuator, the diaphragm more appropriately. The estimated deflection amount can be calculated.

  According to the fourth aspect, the estimated deflection amount of the diaphragm can be calculated more accurately.

  According to the fifth aspect of the present invention, it is possible to appropriately realize a variable throttle type fluid bearing provided with a variable throttle system that can further improve the responsiveness.

It is a perspective view explaining the example of the external appearance of the table feeder to which the variable throttle type fluid bearing is applied. It is II-II sectional drawing of the table feeder shown in FIG. It is a figure explaining the structure of a variable throttle system, and the structure of a variable throttle type fluid bearing. It is a flowchart explaining the example of the process sequence of the control means which comprises the variable aperture system. It is a figure explaining the equivalent circuit of the coil of the electric actuator which comprises a variable aperture system, and the voltage of each position of an equivalent circuit. It is a figure explaining the example of the deflection amount and the bearing clearance distance characteristic memorize | stored in the memory | storage means which comprises the variable aperture system.

Hereinafter, embodiments of a variable throttle system and a variable throttle type fluid bearing according to the present invention will be described in order with reference to the drawings.
● [Overall configuration of table feeder 1 using variable throttle fluid bearing (Figs. 1 and 2)]
1 and 2 show an example of a table feeding device 1 to which a variable throttle system and a variable throttle type fluid bearing of the present invention are applied. The table feeding device 1 includes a base 10 (corresponding to a bearing member) serving as a base, a table 20 (corresponding to a bearing member) serving as a movable body, and a back plate 21 provided on the table 20. A plurality of pockets 31P are provided on the bearing surface that is the opposing surface of the base 10 and the table 20, and the flow rate is adjusted from the variable throttle means 30 to each pocket 31P (that is, to the fluid bearing). Supplied fluid is supplied. A fluid having a predetermined pressure (constant pressure) is pumped to each variable throttle unit 30 from a pump 50 (corresponding to a fluid pumping unit). The fluid is, for example, hydraulic oil, but may be liquid or gas.

● [Configuration of Variable Throttle System 2 and Variable Throttle Fluid Bearing 3 (FIG. 3)]
Next, the configuration of the variable throttle system 2 and the configuration of the variable throttle fluid bearing 3 will be described with reference to FIG. The variable aperture system 2 includes a variable aperture means 30 and a control unit 40. The variable throttle type fluid bearing 3 includes a pocket 31P, a variable throttle system 2, and a pump 50. One control unit 40 is associated with one variable aperture means 30.

  The variable aperture means 30 (variable aperture device) has a housing 31, a diaphragm portion 32, an electric actuator 33, a displacement detection means 34, etc., and is accommodated in a recess provided on the bearing surface of the base 10. Yes. The displacement detection means 34 may be omitted. The variable throttle means 30 is supplied with the fluid pumped from the pump 50, and supplies the fluid whose flow rate is adjusted to the fluid bearing, as will be described later.

  The housing 31 is a case that houses the diaphragm portion 32, the electric actuator 33, and the displacement detection means 34. On the surface of the housing 31 that faces the table 20, a convex portion 31T that continuously protrudes into an annular or polygonal annular shape, and a pocket 31P that is a concave portion formed inside the convex portion 31T, , Is provided. A discharge channel 31 </ b> A that is a through hole that communicates the pocket 31 </ b> P and the inside of the housing 31 is provided at a substantially central portion of the pocket 31 </ b> P. On the opposite side of the pocket 31P in the discharge flow path 31A, a flow path member 31B having a throttle surface 31C facing the diaphragm 32A is provided so as to protrude toward the diaphragm 32A. A diaphragm gap having a diaphragm gap distance S is formed between the diaphragm surface 31C and the diaphragm 32A. In addition, a substantially central portion of the diaphragm 32A is disposed at a position facing the opening 31K serving as an inlet for the fluid Q to the discharge flow path 31A.

  The diaphragm portion 32 is configured by a diaphragm 32A and a support member 32B that supports an edge portion of the diaphragm 32A. The support member 32 </ b> B is fixed to the housing 31 or is a part of the housing 31. The diaphragm 32A is a member that is formed into a substantially disk shape, for example, with a spring steel plate, and the edge portion is supported by the support member 32B. The diaphragm 32A partitions the space in the housing 31 into a supply chamber 35A and a storage chamber 35B, and bends and deforms according to a pressure difference between the supply chamber 35A and the storage chamber 35B. The fluid Q pumped from the pump 50 at a predetermined pressure (constant pressure) flows into the storage chamber 35B and the supply chamber 35A, as shown by a one-dot chain line in FIG. 3, and the fluid Q flowing into the supply chamber 35A Then, it flows into the discharge flow path 31A via the aperture gap of the aperture gap distance S. Then, the fluid Q flowing into the discharge flow path 31A is discharged from the discharge flow path 31A to the pocket 31P, and the table 20 is lifted by the bearing gap distance H. Further, one end of the connecting member 33B is fixed to a substantially central portion of the diaphragm 32A.

  The electric actuator 33 includes a permanent magnet 33F that is a fixed portion and a movable portion 33V that reciprocates in the vertical direction in FIG. The movable portion 33V includes a coil 33C, a drive base 33A, and a connecting member 33B. One end of the connecting member 33B is fixed to a substantially central portion of the diaphragm 32A, and the other end is fixed to the drive base 33A. The drive base 33A is a member that mediates the connection between the coupling member 33B and the coil 33C. For example, the drive base 33A is formed in a disk shape, and the other end of the coupling member 33B is fixed to one surface and the coil is disposed to the other surface. 33C is fixed. The coil 33C is formed in a substantially cylindrical shape with a conductive wire wound around the permanent magnet 33F. The coil 33 </ b> C can reciprocate in the vertical direction in FIG. 3 according to the current supplied from the control unit 40. When the coil 33C moves upward, the diaphragm 32A is pushed upward via the drive base 33A and the connecting member 33B, and the diaphragm 32A is deformed so as to be convex upward. When the coil 33C moves downward, the diaphragm 32A is pulled downward via the drive base 33A and the connecting member 33B, and the diaphragm 32A is deformed to be convex downward. As described above, the electric actuator 33 adjusts the flow rate of the fluid by adjusting the diaphragm gap distance S by flexibly deforming the diaphragm 32A.

  The displacement detection means 34 is, for example, a displacement sensor, and is provided on the drive base 33A, and outputs a detection signal related to the distance D to the support member 32B to the control means. The control means can detect the amount of displacement from the drive base 33A to the support member 32B based on the detection signal from the displacement detection means 34. That is, the control means can detect the actual deflection amount that is the actual deflection amount of the diaphragm 32A based on the detection signal from the displacement detection means 34. As will be described later, the displacement detection unit 34 may be omitted, and an estimated deflection amount that is a deflection amount of the diaphragm 32A estimated by calculation by the control unit may be calculated.

  The control unit 40 (control device) includes a drive circuit 42, terminals 44A and 44B, current detection means 45, storage means 43, control means 41, and the like.

  The drive circuit 42 is a circuit that supplies a current to the coil 33C, and outputs a current that flows from the terminal 44A to the terminal 44B via the coil 33C based on a control signal from the control means 41. The terminal 44A and one end of the coil 33C and the terminal 44B and the other end of the coil 33C are connected by a conductive wire, respectively. The voltage Va, which is the voltage at the terminal 44A, is detected by the control means 41 via voltage detection means (voltage detection circuit) (not shown), and the voltage Vb, which is the voltage at the terminal 44B, is detected by voltage detection means (voltage detection circuit). ) To be detected by the control means 41. Therefore, the control means 41 can calculate the applied voltage E which is the voltage applied to both ends of the coil 33C by calculating the voltage Va-voltage Vb (applied voltage E = voltage Va-voltage Vb). .

  The supply current i supplied from the terminal 44A to the coil 33C returns to the terminal 44B, and then flows to the ground via the current detection means 45 (current detection circuit). The current detection unit 45 is a shunt resistor whose resistance value (r) is known in advance, for example, and the control unit 41 detects the voltage Vi of the current detection unit 45, and the detected voltage Vi and the resistance of the current detection unit 45. Based on the value (r), the supply current i supplied to the coil 33C can be calculated (supply current i = voltage Vi / resistance value r).

  The storage means 43 (storage device) is a storage device such as a Flash ROM. The storage means 43 stores the electric constant of the coil 33C, the value of a proportional constant K (details will be described later) for obtaining an induced electromotive voltage according to the amount of deflection (moving speed) of the diaphragm 32A, the amount of deflection and the bearing. A clearance distance characteristic (details will be described later), a control program, and the like are stored. The electrical characteristics of the coil 33C stored in the storage unit 43 are, for example, the resistance value and inductance of the coil 33C.

  The control unit 41 is, for example, a CPU, and executes a processing procedure described later based on a control program read from the storage unit 43. The control means 41 receives the detection signals of the voltage Va and the voltage Vb from the voltage detection means (not shown), and calculates the voltage Va and the voltage Vb based on the received detection signal. Further, the control means 41 calculates an actual deflection amount, which is an actual deflection amount of the diaphragm 32A, based on the detection signal from the displacement detection means 34. Further, as described above, the control means 41 detects the applied voltage E and the supply current i based on the voltages Va and Vb, and estimates them based on these and the electrical characteristics stored in the storage means 43. The estimated deflection amount that is the deflection amount of the diaphragm 32A is calculated. The target distance, which is the target of the bearing clearance distance H, may be configured to be input to the control means 41 from a control device outside the control unit 40, or may be stored in advance in the storage means 43. May be.

[Processing of control means 41 (FIGS. 4 to 6)]
Next, an example of the processing procedure of the control means 41 will be described using the flowchart shown in FIG. For example, the control means 41 activates the process shown in FIG. 4 at a predetermined time interval (every 1 [ms] or the like).

  In step S10, the control means 41 acquires a target distance which is a target bearing gap distance H, and proceeds to step S20. Note that the target distance may be acquired by communication or the like from a control device different from the control unit 40, or a predetermined target distance may be stored in the storage unit 43 in advance.

  In step S20, the control means 41 detects the applied voltage E and the supply current i, and proceeds to step S30. As described above, the control means 41 detects the voltage Va and the voltage Vb shown in FIG. 3, and obtains the applied voltage E from [Voltage Va−Voltage Vb]. Further, the control means 41 detects the voltage Vi shown in FIG. 3, and obtains the supply current i from [voltage Vi / resistance value r of the current detection means 45].

  In step S30, the control means 41 calculates an estimated deflection amount that is the estimated deflection amount of the diaphragm, or detects an actual deflection amount that is an actual diaphragm deflection amount based on a detection signal from the displacement detection means. Then, the process proceeds to step S40. The calculation procedure of the estimated deflection amount will be described in detail below with reference to FIG.

[Procedure for Estimating Deflection]
FIG. 5 shows an equivalent circuit of the coil 33C in the electric actuator 33 shown in FIG. As shown in FIG. 3, the coil 33C is connected between the terminal 44A and the terminal 44B, and a supply current i is supplied from the terminal 44A. The voltage between the terminal 44A and the terminal 44B is the applied voltage E (see FIG. 3). As shown in FIG. 5, the equivalent circuit of the coil 33C can be regarded as a circuit in which a resistor 33CR having an armature resistance value R and a coil 33CL having an (armature) inductance L are connected in series. Here, the voltage applied to the resistor 33CR can be represented by the product (= R * i) of the armature resistance value R and the supply current i. The voltage applied to the coil 33CL can be represented by the product (= L * di / dt) of the (armature) inductance L and the amount of change in the supply current i per unit time. When the coil 33C is operated, an induced electromotive voltage e is generated based on the movement amount (movement speed) of the coil 33C corresponding to the deflection amount of the diaphragm. Therefore, as shown in FIG. 5, the following (Formula 1) is established.
E = [R * i] + [L * di / dt] + e (Formula 1)

Here, the induced electromotive voltage e can be expressed by a product (= K * dx / dt) of a proportionality constant K and a change amount of the coil position x per unit time. By substituting this into (Equation 1), the following (Equation 2) can be obtained. Note that x is the amount of movement in the vertical direction in FIG. 3, and the proportionality constant K is assumed to be known in advance.
E = [R * i] + [L * di / dt] + [K * dx / dt] (Formula 2)

Further, from the transient phenomenon theory, it is replaced with di / dt = (d / dt) * i = si which is a time derivative of current, and dx / dt = (d / dt) * x = sx which is a time derivative of position. The above (Formula 2) can be expressed by the following (Formula 3).
E = [R * i] + [L * si] + [K * sx] (Formula 3)

By arranging the above (Equation 3), the following (Equation 4) can be obtained. In (Expression 4), x corresponds to the estimated deflection amount. As described above, R is the (armature) resistance value of the coil 33C stored in the storage means, and L is the (armature) inductance of the coil 33C stored in the storage means. The applied voltage E can be obtained from the voltage Va and the voltage Vb as shown in FIG. 3, and the supply current i is the voltage Vi shown in FIG. 3 and the resistance value r of the current detecting means 45 (stored in the storage means). It can be obtained from. Therefore, the control means 41 can calculate the estimated deflection amount (= x) of the diaphragm by using (Equation 4).
x = [E- (R + sL) i] / [sK] (Formula 4)

  Returning to the flowchart of FIG. 4, in step S40, the control means 41 determines the estimated deflection amount of the diaphragm calculated in step S30 or the detected actual deflection amount of the diaphragm, and the deflection amount / bearing gap stored in the storage means. Based on the distance characteristics, a predicted bearing gap distance, which is a predicted bearing gap distance, is calculated, and the process proceeds to step S50.

  Here, the deflection amount / bearing gap distance characteristics will be described with reference to FIG. For example, the deflection amount / bearing gap distance characteristic is a graph (also referred to as a map) in which the horizontal axis is the deflection amount (estimated deflection amount or actual deflection amount) and the vertical axis is the bearing gap distance. This deflection amount / bearing gap distance characteristic is obtained by setting the deflection amount to various values using, for example, the actual table feeder 1 shown in FIGS. 1 and 2, and actually determining the bearing gap distance at each deflection amount. Measure to create. Alternatively, a virtual model of the table feeder 1 is created by simulation. Alternatively, it may be created from various characteristics known in advance (a graph showing the amount of deflection with respect to the pressure applied to the pocket, a graph showing the bearing gap distance with respect to the pressure applied to the pocket, etc.). There are no particular limitations on the method of creating the deflection amount / bearing gap distance characteristics. The control means 41 uses the deflection amount / bearing gap distance characteristics shown in FIG. 6 and the estimated deflection amount calculated in step S30 or the detected actual deflection amount to obtain an estimated deflection amount (or actual deflection amount). The corresponding bearing gap distance is obtained, and the obtained bearing gap distance is set as the predicted bearing gap distance. Thus, the control means 41 calculates the predicted bearing gap distance based on the control state of the electric actuator.

  In step S50, the control means 41 calculates a deviation between the target distance acquired in step S10 and the predicted bearing gap distance obtained in step S40, and the process proceeds to step S60. Deviation = target distance-predicted bearing clearance distance.

  In step S60, the control means 41 calculates a control amount (current) based on the deviation, and proceeds to step S70. Note that the control amount calculation method is not particularly limited.

  In step S70, the control means 41 starts output of a control signal (for example, a PWM [Pulse Width Modulation] signal corresponding to the control amount and the power supply voltage) corresponding to the control amount (current) and performs processing. finish.

  As described above, the control unit 41 does not detect the actual bearing gap distance H shown in FIG. 3 and the predicted bearing gap distance calculated by the control unit 41 is equal to the target distance as described in the present embodiment. Thus, feedback control of the current supplied to the coil of the electric actuator is performed. Therefore, even when the mass is very large and the delay time until the actual bearing gap distance changes is large, the predicted bearing gap distance that changes instantaneously regardless of the mass is used, so the responsiveness is further improved. be able to. For this reason, compared with the case where feedback control is performed so that the actual bearing gap distance becomes the target distance, the dynamic rigidity can be greatly improved.

  Various changes, additions, and deletions can be made to the configuration, structure, shape, and the like of the variable throttle system and variable throttle fluid bearing of the present invention without departing from the spirit of the present invention. For example, the processing procedure of the control means is not limited to the flowchart shown in FIG. In the description of the present embodiment, the example in which the variable throttle means 30 is provided on the bearing surface of the base 10 has been described. However, the variable throttle means 30 may be provided on the bearing surface of the table 20.

  The variable throttle system and variable throttle type fluid bearing described in the present embodiment are not limited to the table feeding device, and can be applied to various devices. For example, the variable throttle system and variable throttle type fluid bearing described in this embodiment can be applied to a spindle of a machine tool whose bearing surface is not a flat surface but a cylindrical surface.

  The fluid dynamic bearing described in this embodiment includes a hydrostatic bearing.

DESCRIPTION OF SYMBOLS 1 Table feeder 2 Variable throttle system 3 Variable throttle fluid bearing 10 Base (bearing member)
20 Table (bearing member)
21 Back plate 30 Variable throttle means 31 Housing 31A Discharge flow path 31B Flow path member 31C Restriction surface 31K Opening 31P Pocket 32 Diaphragm part 32A Diaphragm 32B Support member 33 Electric actuator 33A Drive base 33B Connecting member 33C Coil 33F Permanent magnet 34 Displacement detection Means 35A Supply chamber 35B Reservoir 40 Control unit 41 Control means 42 Drive circuit 43 Storage means 44A, 44B Terminal 45 Current detection means 50 Pump (fluid pressure sending means)
D Distance H Bearing clearance distance S Diaphragm clearance distance

Claims (5)

A variable throttle system that adjusts the flow rate of the fluid that has been pumped, supplies the fluid whose flow rate has been adjusted to the fluid bearing, and floats the bearing member from the bearing member by a bearing clearance distance,
A variable throttle means provided with an electric actuator that is supplied with a pumped fluid and supplies a fluid whose flow rate is adjusted to the fluid bearing and adjusts the flow rate of the fluid;
A drive circuit for driving the electric actuator;
Control means for controlling the electric actuator via the drive circuit,
The control means includes
Without detecting the actual distance of the bearing gap distance, based on the control state of the electric actuator, calculate a predicted bearing gap distance that is a predicted bearing gap distance;
Feedback control of the electric actuator so that the calculated predicted bearing gap distance becomes a target distance;
Variable aperture system. A variable throttle system that adjusts the flow rate of the fluid that has been pumped, supplies the fluid whose flow rate has been adjusted to the fluid bearing, and floats the bearing member from the bearing member by a bearing clearance distance,
A variable throttle means provided with an electric actuator that is supplied with a pumped fluid and supplies a fluid whose flow rate is adjusted to the fluid bearing and adjusts the flow rate of the fluid;
A drive circuit for driving the electric actuator;
Control means for controlling the electric actuator via the drive circuit;
Storage means,
The variable aperture means includes
A discharge flow path for discharging a fluid supplied to the fluid bearing;
A diaphragm that is disposed at a position facing an opening that serves as an inlet for fluid to the discharge flow path, and that can be flexibly deformed so that a diaphragm gap distance formed between the opening and the opening is variable.
The electric actuator for flexibly deforming the diaphragm based on a control signal from the control means;
In the storage means,
The deflection amount / bearing gap distance characteristic indicating the bearing gap distance with respect to the deflection amount of the diaphragm, and the electrical characteristics of the electric actuator are stored,
The control means includes
The electrical characteristics stored in the storage means, an applied voltage which is a voltage applied to the electric actuator measured using voltage detection means provided in the drive circuit, and provided in the drive circuit An estimated deflection amount, which is an estimated deflection amount of the diaphragm, based on a supply current which is a current supplied to the electric actuator measured using the current detection means, or provided in the diaphragm The actual deflection amount, which is the actual deflection amount of the diaphragm, is detected using the deflection amount detection means provided,
Based on the estimated deflection amount or the actual deflection amount and the deflection amount / bearing gap distance characteristic stored in the storage means, a predicted bearing gap distance that is a predicted bearing gap distance is calculated,
Feedback control of the electric actuator so that the calculated predicted bearing gap distance becomes a target distance;
Variable aperture system. The variable aperture system according to claim 2,
The electrical characteristics stored in the storage means are a resistance value of the electric actuator and an inductance of the electric actuator.
Variable aperture system. The variable aperture system according to claim 3,
When calculating the estimated deflection amount, the control means sets the applied voltage, the voltage based on the resistance value and the supply current, the voltage based on the inductance and the supply current, and the deflection amount of the diaphragm. The estimated deflection amount is calculated based on the induced electromotive force of the electric actuator based on the movement amount of the diaphragm in response.
Variable aperture system. The variable throttle system according to any one of claims 1 to 4, wherein a fluid whose flow rate is adjusted is supplied to the fluid bearing.
Fluid pumping means for pumping fluid to the variable throttle system;
Variable throttle type fluid bearing.

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