JP2019210954A - Static pressure fluid support device - Google Patents

Abstract

To provide a static pressure fluid support device capable of quickly changing a pressure in a static pressure pocket according to magnitude of disturbance load in a case when the disturbance load generates in the static pressure fluid support portion, and adjusting a thickness of a fluid film formed between guide surfaces to a proper thickness in a short time.SOLUTION: A static pressure fluid support device 1 includes a static pressure pocket 20, a fluid supply device 30, a fluid supply flow channel 40, a supply-side fixed throttle 50, a fluid discharge flow channel 60, a discharge-side active type variable throttle valve 70 for adjusting a flow rate of the fluid discharged to a drain portion 21 by displacement of a valve element 86 through a connection member 79 by operations of a valve portion 78, the connection member 79 and an actuator 71, a clearance detection portion 90 detecting a clearance α between a guide surface 12a and a guide surface 11a, and a control device 100.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydrostatic fluid support device.

  Conventionally, in a hydrostatic fluid support (bearing) device, an opposed moving body and a fixed body are each provided with an opposing guide surface (including a bearing surface), and one of the opposing guide surfaces is provided with a static pressure pocket. is there. In such a static pressure fluid support (bearing) device, the fluid pressurized by the pump is supplied to the static pressure pocket. Thus, a fluid film having a predetermined thickness is formed between the guide surfaces, the guide surfaces are supported in a non-contact manner, friction is reduced, and the movable body and the fixed body can be relatively moved with high accuracy.

  At this time, in the hydrostatic fluid support device, when a disturbance force acts on the fluid film due to a disturbance load applied between the guide surfaces, a fluid film having a thickness necessary for maintaining the support rigidity is not formed, and the support rigidity is lowered. Therefore, in order to stably maintain the support rigidity, it is necessary to control the supply pressure to the static pressure pocket according to the disturbance load.

  In order to cope with this, for example, in the hydrostatic fluid support (bearing) device of Patent Document 1, an oil drain hole (discharge channel) penetrating from the land to the side surface of the inner sleeve is formed. A variable throttle is connected to the discharge channel, and the thickness of the fluid film is adjusted and the support rigidity is controlled by adjusting the variable throttle according to the disturbance load.

  Further, the hydrostatic fluid support (bearing) device of Patent Document 2 does not have a hydrostatic pocket, but is provided with a discharge flow path having a variable throttle on one of the opposing guide surfaces (bearing surfaces). . When fluid (air) is discharged from the discharge channel through the variable throttle, the thickness of the fluid film is adjusted and the support (bearing) rigidity is controlled by adjusting the variable throttle according to the disturbance load. Is done.

  Further, the static pressure fluid support (bearing) device of Patent Document 3 includes a suction flow path for supplying fluid to the static pressure pocket and a discharge flow path for discharging fluid from the static pressure pocket. The suction flow path is provided with a diaphragm type variable throttle device, and the discharge flow path is provided with a diaphragm type or a variable throttle adjusted by the operation of an actuator. Thus, the pressure in the static pressure pocket is adjusted according to the disturbance load by the diaphragm type variable throttle device provided mainly in the suction flow path. At this time, the variable throttle provided in the discharge channel finely adjusts the pressure fluctuation in the static pressure pocket. Thus, the thickness of the fluid film between the guide surfaces is adjusted, and the support (bearing) rigidity is controlled.

Japanese Patent No. 4134541 Japanese Patent Laid-Open No. 4-131518 Japanese Patent No. 5870500

  However, in the hydrostatic fluid support (bearing) devices of Patent Documents 1 and 2, the discharge flow path is provided through one of the opposing guide surfaces. For this reason, it is difficult to efficiently discharge the fluid supplied from the suction flow path and accurately adjust the pressure of the fluid between the opposing guide surfaces, that is, the thickness of the fluid film in a short time.

  In addition, the hydrostatic fluid support (bearing) device disclosed in Patent Document 3 includes a diaphragm type variable throttle device in the suction passage. For this reason, when the pressure in the static pressure pocket fluctuates due to a disturbance load and the gap fluctuates, the diaphragm of the variable throttle mainly in the suction flow path operates to adjust the pressure in the static pressure pocket. At this time, in the diaphragm type variable aperture, due to its characteristics, a time difference occurs between the time when the diaphragm is operated and the time when the pressure in the static pressure pocket is saturated. Therefore, even if the pressure is finely adjusted by the variable throttle of the discharge channel, the pressure in the static pressure pocket, that is, the thickness of the fluid film (support rigidity) between the opposing guide surfaces is adjusted with high accuracy in a short time. It is difficult.

  The present invention has been made to solve the above problems, and when a disturbance load is generated in the static pressure fluid support portion, the pressure in the static pressure pocket is quickly changed according to the magnitude of the disturbance load. It is another object of the present invention to provide a hydrostatic fluid support device capable of adjusting the thickness of a fluid film formed between guide surfaces to an appropriate thickness in a short time.

  A static pressure fluid support device according to the present invention includes a static pressure pocket provided on a guide surface of a moving body or a fixed body, a fluid supply device that supplies fluid pressurized to the static pressure pocket, and the fluid supply device. A fluid supply passage that forms a fluid passage leading to the static pressure pocket, a supply-side fixed throttle provided in the fluid supply passage, and a fluid that forms a fluid passage leading from the static pressure pocket to the drain portion A discharge passage, a valve portion including an actuator, a valve body, and a valve seat; and a connecting member that transmits the operation of the actuator to the valve body. The valve portion is provided in the fluid discharge passage. When the valve body is displaced through the connecting member by the operation, the throttle amount between the valve body and the valve seat is changed, and the flow rate of the fluid discharged from the valve portion to the drain portion is changed. Adjustment Active variable throttle valve on the discharge side, a gap detection unit for detecting a gap between the guide surface of the movable body and the guide surface of the fixed body, and the size of the gap detected by the gap detection unit The actuator is controlled accordingly, the displacement amount of the valve body of the active variable throttle valve is changed to adjust the throttle amount, the flow rate of the fluid discharged from the valve portion is changed, A control device that sets the gap between the guide surfaces to a predetermined size.

  Thus, the static pressure fluid support device includes a fixed throttle in the fluid supply channel. For this reason, fluid is always supplied into the static pressure pocket at a constant pressure (flow rate) corresponding to the discharge pressure of the pump. In addition, an active (active) variable throttle valve is provided in the fluid discharge channel connected to the static pressure pocket. The active variable throttle valve is operated according to the size of the gap between the guide surface of the moving body and the guide surface of the fixed body detected by the gap detector, and the pressure in the static pressure pocket, and thus the guide. The gap between the surfaces is controlled to be a predetermined size.

  As described above, in the configuration described above, the pressure in the static pressure pocket is mainly adjusted by the operation (opening / closing) of the active variable throttle valve provided in the fluid discharge channel. That is, it is possible to adjust the pressure in the static pressure pocket, that is, to adjust the size of the gap between the guide surface of the moving body and the guide surface of the fixed body, in a state that is hardly affected by the fluid supply side. .

  At this time, the active variable throttle valve discharges the fluid in the static pressure pocket to the atmosphere side. Therefore, a large differential pressure can be easily set between the upstream side and the downstream side of the active variable throttle valve. For this reason, since a large flow rate fluid can be discharged from the active variable throttle valve in a short time, the pressure in the static pressure pocket can also be adjusted in a short time. As a result, even if a disturbance load occurs and the pressure in the static pressure pocket needs to be adjusted, the pressure in the static pressure pocket is controlled according to the magnitude of the disturbance load by controlling the discharge-side active variable throttle valve. It can be changed quickly, and the thickness of the fluid film formed between the guide surfaces can be adjusted to an appropriate size in a short time.

It is the schematic of the static pressure fluid support apparatus which concerns on 1st embodiment of this invention. It is an enlarged view of the valve part of the active variable throttle valve in FIG. It is a flowchart of the action | operation of the static pressure fluid support apparatus which concerns on 1st embodiment. It is the schematic of the modification 2 of 1st embodiment. It is the schematic of the static pressure fluid support apparatus which concerns on 2nd embodiment of this invention. It is a figure explaining the state at the time of the power supply interruption | blocking of the switching valve of FIG. It is the schematic of the modification 1 of 2nd embodiment.

<1. First embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a hydrostatic fluid support device 1 according to a first embodiment of the present invention, and FIG. 2 is a diagram of a valve portion 78 constituting the active (active) variable throttle valve 70 shown in FIG. It is sectional drawing. The arrows in the fluid path indicate the direction in which the fluid flows.

(1-1. Configuration of Static Pressure Fluid Support Device)
As shown in FIG. 1, the hydrostatic fluid support device 1 according to the present embodiment uses a linear motion table 11 (corresponding to a moving body), for example, to lubricate a fixed table 12 (corresponding to a fixed body) It is a support device that supports the fluid F that is oil so as to be relatively movable with low friction. As an example, the linear motion table 11 and the fixed table 12 correspond to a traverse base (corresponding to a fixed table) and a grindstone base (corresponding to a linear motion table) in a grinding machine (actually, the fixed table 12 is below and the linear motion is The table is placed on top).

  The static pressure fluid support device 1 includes the linear motion table 11 and the fixed table 12, the static pressure pocket 20, the fluid supply device 30, the fluid supply channel 40, the supply-side fixed throttle 50, and the fluid discharge flow. A path 60, the above-described discharge-side active variable throttle valve 70, a displacement sensor 90 (corresponding to a gap detection unit), and a control device 100 are provided.

  As shown in FIG. 1, the static pressure pocket 20 is formed on the guide surface 11 a of the linear motion table 11 in the present embodiment. The bottom surface 20c of the static pressure pocket 20 is provided with a fluid supply hole 20a and a fluid discharge hole 20b penetrating the lower surface. The fluid supply hole 20a is fitted with a fixed throttle 50 on the supply side which will be described in detail later. Further, the guide surface 12 a of the fixed table 12 is disposed so as to face the guide surface 11 a of the linear motion table 11 and the static pressure pocket 20.

  The fluid supply device 30 is a hydraulic pump P. As shown in FIG. 1, the fluid supply device 30 is connected to a supply-side fixed throttle 50 fitted in the fluid supply hole 20 a of the static pressure pocket 20 via a fluid supply channel 40. That is, the fluid supply channel 40 forms a fluid passage from the fluid supply device 30 to the static pressure pocket 20. The fixed throttle 50 includes a throttle channel 51 which is provided in the fluid supply channel 40 and is formed to penetrate with a channel diameter φD1 slightly smaller than the channel diameter (not shown) of the fluid supply channel 40.

  As a result, when the fluid supply device 30 operates and the fluid having the supply pressure Ps is supplied to the upstream side of the fixed throttle 50, the fluid is reduced to the predetermined pressure Pr in the fixed throttle 50. The fluid reduced to the predetermined pressure Pr is supplied into the static pressure pocket 20. At this time, the predetermined pressure Pr of the fluid supplied to the static pressure pocket 20 is larger than the atmospheric pressure Patm (Pr> Patm). That is, the fluid supplied to the static pressure pocket 20 is a fluid pressurized against the atmospheric pressure Patm.

  A fluid film having a predetermined thickness α is formed between the guide surface 11a and the guide surface 12a by the fluid supplied to the static pressure pocket 20, and the guide surface 12a is supported. After the fluid film is dynamically formed, the drain part 21 passes through the path L1 through which the fluid is directly discharged to the drain part 21 and the fluid discharge hole 60b of the static pressure pocket 20 through the fluid discharge channel 60 described above. It is maintained by continuously performing the discharge to the drain portion 21 through the paths L2 respectively discharged to. One end of the fluid discharge channel 60 forming the path L2 is connected to the fluid discharge hole 20b of the static pressure pocket 20, and the other end is connected to the drain portion 21 (fluid storage portion). Details will be described later.

(1-1-1. Active variable throttle valve)
The discharge-side active variable throttle valve 70 is connected to an end of a pipe 60 a included in the fluid discharge channel 60. Specifically, the valve portion 78 included in the active variable throttle valve 70 is connected to the end of the pipe 60 a of the fluid discharge channel 60. In addition, the active variable throttle valve 70 is arranged to be spaced downward from the linear motion table 11 (moving body) and the fixed table 12 (fixed body) in the gravity direction.

  At this time, in this embodiment, the fluid discharge channel 60 is not provided with a pipe between the valve portion 78 and the drain portion 21, and the drain portion in which the fluid is disposed below the valve portion 78 in the gravity direction. Drop onto 21 and discharge. In this case, the fluid drop trajectory is regarded as a part of the fluid discharge channel 60.

  As shown in FIG. 1, the active variable throttle valve 70 includes an actuator 71, a valve portion 78, and a connecting member 79. The valve portion 78 and the actuator 71 are formed separately. Further, the valve portion 78 is disposed adjacent to the actuator 71 in the horizontal direction.

(1-1-2. Actuator 71)
The actuator 71 includes a cylindrical housing 72. The actuator 71 includes a voice coil motor 73 (hereinafter referred to as VCM 73 only) in a cylindrical housing 72. The VCM 73 includes a stator 74 that is fixed to the inner peripheral surface 72 a of the housing 72, and a mover 75 that can move in the vertical direction of FIG. 2 with respect to the stator 74. In addition, the VCM 73 includes an annular permanent magnet (not shown) fixed to the inner peripheral side of the stator 74, a coil bobbin (not shown) provided in the mover 75, and a voice coil (not shown) wound around the coil bobbin. Etc.

  When a current is passed through the voice coil (not shown), a thrust is generated in the voice coil in one of the vertical directions in FIG. Further, by passing a current in the opposite direction to the above, a thrust is generated in either one of the vertical directions in FIG. Since the VCM 73 is a known electromagnetic linear motor, further detailed description is omitted. The actuator 71 is connected to the control device 100. Under the control of the control device 100, the VCM 73 operates and the mover 75 is driven in the vertical direction.

(1-1-3. Valve part)
As shown in FIGS. 1 and 2, the valve portion 78 includes a housing 81. As shown in FIG. 2, the valve portion 78 includes an inflow hole 82, an outflow hole 85, a diaphragm 86 (valve element), a fluid storage chamber 87, a fluid discharge chamber 88, a valve seat 89, and a fluid in the housing 81. A first communication passage 83 and a second communication passage 84 are provided to allow communication between the storage chamber 87 and the fluid discharge chamber 88.

  The housing 81 includes a first housing 81a on the upper side and a second housing 81b on the lower side with the diaphragm 86 as a boundary. The first housing 81a and the second housing 81b are assembled so that the fluid storage chamber 87 and the fluid discharge chamber 88 face each other with the diaphragm 86 interposed therebetween. At this time, the outer periphery of the diaphragm 86 is sandwiched between the outer periphery 81a1 of the first housing 81a and the outer periphery 81b1 of the second housing 81b, whereby the diaphragm 86 is fixed to the housing 81 and the valve portion 78 is formed. The

  In this way, the diaphragm 86 is gripped between the fluid storage chamber 87 and the fluid discharge chamber 88 to partition the fluid storage chamber 87 and the fluid discharge chamber 88, and the lower surface in FIG. Is opposed to the valve seat 89 with a predetermined gap D therebetween. The diaphragm 86 is an elastic member made of steel or the like, and a gap D formed by the diaphragm 86 and the valve seat 89 is a throttle opening D (corresponding to a throttle amount). The diaphragm 86 can be deformed from the minimum opening DL to the maximum opening DH, and an intermediate position between the minimum opening DL and the maximum opening DH is an initial position in a no-load state.

  The inflow hole 82 is provided above the first housing 81a in FIG. The inflow hole 82 penetrates from the outside into the fluid storage chamber 87 and is connected to the fluid discharge hole 20 b of the static pressure pocket 20 through the pipe 60 a of the fluid discharge channel 60. The valve seat 89 is formed at the lower center of the second housing 81b. The fluid discharge chamber 88 is formed in a ring shape around the valve seat 89.

  At the center of the valve seat 89, an outflow hole 85 is formed as a through hole. The outflow hole 85 has an opening 85a on the outlet side that opens into the atmospheric pressure space. And as above-mentioned, the opening 85a and the drain part 21 are connected by a part of fluid discharge flow path 60 formed with the fall locus | trajectory of a fluid. As described above, in this embodiment, the fluid discharge channel 60 is not provided with a pipe between the valve portion 78 and the drain portion 21, and the fluid flows from the valve portion 78 to the drain portion 21 disposed below in the gravity direction. It falls and is discharged.

  The first communication passage 83 and the second communication passage 84 are provided on the side walls of the fluid storage chamber 87 and the fluid discharge chamber 88, respectively, and as shown in FIG. The storage chamber 87 and the fluid discharge chamber 88 are communicated with each other. Thereby, the fluid that has passed through the inflow hole 82 and has flowed into the fluid storage chamber 87 from the static pressure pocket 20 passes through the first communication passage 83 and the second communication passage 84 and is also supplied to the fluid discharge chamber 88.

  The pressure P 1 (first pressure) other than the valve seat 89 in the fluid storage chamber 87 and the fluid discharge chamber 88 is close to the pressure of the static pressure pocket 20. The fluid supplied into the fluid discharge chamber 88 is a pressure difference between the pressure P1 and the atmospheric pressure which is the pressure P2 (second pressure) in the vicinity of the valve seat 89 in the fluid discharge chamber 88, and the opening of the throttle (gap). A flow rate corresponding to the degree D flows out (discharges) from the throttle (gap) to the drain portion 21 via the outflow hole 85 and the fluid discharge flow path 60 having no piping.

  The connecting member 79 is a member that directly transmits the operation (movement) of the actuator 71 to the diaphragm 86. Therefore, the connecting member 79 is formed of a highly rigid material such as an iron-based metal material. The connecting member 79 is formed in a shape in which the U-shape is turned sideways in FIG. 1, one end is fixed to the lower surface of the mover 75 of the VCM 73, and the other end is inserted into the outflow hole 85 of the valve portion 78 and then the diaphragm. It is fixed to a substantially central portion of the lower surface of 86.

  At this time, even if the other end of the connection member 79 is inserted into the outflow hole 85, the connection member 79 and the connection member 79 are configured so that a sufficient amount of fluid can flow out (discharge) from the outflow hole 85 toward the drain portion 21. The area of each axis orthogonal cross section of the outflow hole 85 is set. As is apparent from the above, the actuator 71 of the active variable throttle valve 70 is disposed at a predetermined position in the atmosphere and does not directly contact the fluid discharged from the valve portion 78. Thereby, although it is VCM73 which can operate | move also in fluids, such as oil, the durability improves more.

  The displacement sensor 90 (corresponding to the gap detection unit) is embedded in the guide surface 11 a of the linear motion table 11. The displacement sensor 90 detects the displacement between the guide surface 11a and the guide surface 12a, that is, the gap α between the guide surface 11a and the guide surface 12a.

  The control device 100 controls the actuator 71 according to the size of the gap α detected by the displacement sensor 90 (gap detection unit), and sets the gap D between the diaphragm 86 (valve element) of the valve unit 78 and the valve seat 89, for example. The aperture amount is adjusted by changing to a desired gap D1 (not shown). As a result, the flow rate of the fluid discharged from the gap D of the valve portion 78 is changed (adjusted), the pressure in the static pressure pocket 20 is changed, and the gap α between the guide surfaces 11a and 12a is set to a predetermined value. The size of

  As shown in FIG. 1, the control device 100 includes a sensor amplifier 101, a controller 102, and an actuator driving unit 103. The sensor amplifier 101 acquires and amplifies the detection value k1 of the gap α detected by the displacement sensor 90. The controller 102 acquires the detection value k1 amplified by the sensor amplifier 101.

  Then, the controller 102 calculates a difference k2 (= k0−k1) between the value k0 corresponding to the target gap α0 between the guide surfaces 11a and 12a to be targeted and the detected value k1, and transmits the difference to the actuator driving unit 103. . The target gap α0 that should be the target is stored in the controller 102 in advance.

  The actuator drive unit 103 generates a drive signal S1 of the VCM 73 based on the difference k2 calculated by the controller 102, outputs the drive signal S1 to the voice coil of the actuator 71, and controls the mover 75 of the VCM 73 to be displaced to a desired state. . At this time, the desired state of the mover 75 is a displacement that enables the gap α between the guide surface 11a and the guide surface 12a to be the target gap α0.

(1-2. Operation)
(1-2-1. Normal operation)
Next, the operation during normal operation will be described based on the flowchart of FIG. First, the premise of operation will be described. In the first embodiment, as shown in FIG. 1, in the hydrostatic fluid support device 1, for example, a fluid pressurized to a supply pressure Ps by a pump P that operates at a constant rotational speed is supplied to a predetermined pressure by a fixed throttle 50. Depressurize to Pr. Then, the fluid reduced to the predetermined pressure Pr is supplied to the static pressure pocket 20.

  As described above, the fluid supplied to the static pressure pocket 20 causes the fluid to flow between the guide surface 11a and the guide surface 12a, and a fluid film having a predetermined thickness α0 (= target gap) is formed. 12a is supported. This state is the initial state. In such a state, for example, a positive disturbance load is applied between the guide surface 11a supported by the hydrostatic fluid and the guide surface 12a. When a positive disturbance force acts on the fluid film due to a positive disturbance load, for example, the thickness α of the fluid film becomes smaller than a predetermined thickness α0 of the fluid film in the initial state. In the above description, the positive disturbance load refers to a load in a direction in which the thickness of the fluid film decreases. For convenience of explanation, as described above, the fluid film thickness α in the initial state is described as a target predetermined gap α0.

  In the first step S10, in the above state, the displacement sensor 90 (gap detection unit) detects the detection value k1 corresponding to the gap α between the guide surfaces 11a and 12a on which the fluid film is formed. In the second step S <b> 20, the sensor amplifier 101 amplifies the detection value k <b> 1 acquired from the displacement sensor 90 and transmits it to the controller 102. At this time, the size of the gap α (detected value k1) detected by the displacement sensor 90 (gap detection unit) is smaller than the predetermined gap α0 (= target gap) (α <α0).

  That is, by applying a disturbance force to the static pressure fluid support portion, the pressure in the static pressure pocket 20 becomes insufficient to maintain the predetermined gap α0, and the gap α becomes smaller than the predetermined gap α0. Yes. For this reason, the control device 100 needs to perform control so as to increase the deficient pressure with respect to the pressure in the static pressure pocket 20 and return the gap α to the predetermined gap α0.

  In the third step S30, the controller 102 calculates the difference k2 (= k0−k1) between the detected value k1 and the value k0 corresponding to the predetermined gap α0 between the guide surfaces 11a and 12a to be targeted, and the actuator Transmit to the drive unit 103. At this time, the predetermined gap α0 to be targeted is stored in the controller 102 in advance.

  In the fourth step S40, the actuator drive unit 103 generates a drive signal S1 for the VCM 73 based on the difference k2 calculated by the controller 102. Then, the actuator drive unit 103 outputs the generated drive signal S to the voice coil of the VCM 73, and displaces the mover 75 of the VCM 73, for example, downward by a predetermined displacement amount s (not shown) in FIG.

  Accordingly, the connecting member 79 connected to the mover 75 is displaced downward by a displacement amount s (not shown), and the valve portion is connected to the end of the connecting member 79 on the side opposite to the mover 75 side. The central portion of the diaphragm 86 (valve element) 78 is displaced downward by a displacement amount s (not shown) following the downward movement of the connecting member 79.

  As a result, the opening D of the throttle (gap) of the valve portion 78 is changed to the reduction side (closed side). For this reason, after the opening degree D is changed, the flow rate of the fluid discharged from the valve portion 78 to the drain 21 is reduced more than the flow rate discharged from the valve portion 78 to the drain portion 21 in the initial state, and the outflow ( Discharged).

  Therefore, the pressure of the fluid supplied from the pump P to the static pressure pocket 20 via the fixed throttle 50 increases as the flow rate of the fluid discharged from the valve portion 78 to the drain portion 21 decreases. The size of the gap α between the guide surfaces 11a and 12a is a target predetermined gap α0.

  More specifically, the diaphragm 86 (valve element) is formed on the first surface 86a side, which is the upper side of the diaphragm 86 in FIG. A valve that is formed on the second surface 86b side of the diaphragm 86 in the valve portion 78 and communicates with the drain portion 21 in the fluid storage chamber 87 communicated via the discharge flow path 60. Due to the pressure difference with the second pressure P2 around the valve seat 89 in the fluid discharge chamber 88 of the portion 78, an urging force is applied and displaced.

  A fluid having a flow rate corresponding to the pressure difference between the first pressure P1 other than the vicinity of the valve seat 89 in the fluid discharge chamber 88 after the displacement of the diaphragm 86 and the atmospheric pressure as the pressure of the drain portion 21 is supplied from the valve portion 78. It is discharged to the drain part 21. At this time, the first pressure P1 other than the vicinity of the valve seat 89 is equal to the first pressure P1 in the fluid storage chamber 87. Thus, in the active variable throttle valve 70, the fluid in the static pressure pocket 20 is discharged to the atmosphere side.

  When the gap α is not the target gap α0, the processes from the first step S10 to the fourth step S40 may be repeated until it is confirmed that the gap α has become the target gap α0.

(1-2-2. Operation when power is cut off)
Next, the operation when the energization to the actuator 71 of the hydrostatic fluid support device 1 is interrupted will be described. In the diaphragm 86 (valve element) of the valve portion 78 according to the first embodiment, the energization of the actuator 71 is interrupted, the operating force generated by the displacement of the mover 75 of the actuator 71 is canceled, and the operating force is reduced to the diaphragm 86 (valve element). ), The vertical biasing force is applied only by the pressure difference between the first pressure P1 in the fluid storage chamber 87 and the second pressure P2 around the valve seat 89 in the fluid discharge chamber 88. It can be displaced.

  For this reason, even if it does not change the flow path diameter of the fixed throttle 50 on the supply side, the amount of fluid discharged from the valve portion 78 to the drain portion 21 is adjusted only by the operation of the diaphragm 86 (valve element) due to the pressure difference between the upper and lower sides. Can be done accordingly. Therefore, since the fixed aperture 50 applied when the energization to the actuator 71 described above is not interrupted can be applied as it is, it can be easily handled and contributes to cost reduction.

  In the first embodiment, in the description of the operation, a positive disturbance load is applied between the guide surface 11a supported by the hydrostatic fluid and the guide surface 12a, and the thickness α of the fluid film is equal to the fluid in the initial state. It has been described that the thickness is smaller than the predetermined thickness α0 of the film. However, when a negative disturbance load is applied between the guide surface 11a supported by the hydrostatic fluid and the guide surface 12a, the thickness α of the fluid film is larger than the predetermined thickness α0 of the fluid film in the initial state. growing.

  In this case, the first step S10 is different from the first step S10 except that the movable element 75, the connecting member 79 connected to the movable element 75, and the center part of the diaphragm 86 (valve element) are displaced upward. What is necessary is just to perform the process similar to 4th process S40.

  Thereby, the opening degree D of the throttle (gap) of the valve part 78 is changed to the opening degree of the expansion side (opening side) which is a desired opening degree (throttle amount). For this reason, after the opening degree D is changed, the flow rate of the fluid discharged from the valve unit 78 to the drain unit 21 is increased in comparison with the flow rate discharged from the valve unit 78 to the drain unit 21 in the initial state. It flows out (discharges) from the (gap) to the drain part 21 through the outflow hole 85 and the fluid discharge channel 60.

  Accordingly, the pressure of the fluid supplied from the pump P to the static pressure pocket 20 via the fixed throttle 50 decreases as the flow rate of the fluid discharged from the valve portion 78 to the drain portion 21 increases. As a result, the size of the gap between the guide surfaces 11a and 12a is set to a target predetermined gap α0.

  At this time, as described above, the active variable throttle valve 70 discharges the fluid in the static pressure pocket 20 to the atmosphere side. Therefore, it is possible to easily set a large differential pressure between the upstream side and the downstream side of the valve portion 78 in the active variable throttle valve 70 with respect to the atmospheric pressure. Accordingly, when it is desired to quickly reduce the pressure in the static pressure pocket 20, a large amount of fluid can be discharged from the valve portion 78 toward the drain portion 21 in a short time. Can be adjusted in a short time, and the thickness of the fluid film formed between the guide surfaces 11a and 12a can be adjusted to an appropriate size in a short time.

(1-3. Effects of First Embodiment)
According to the first embodiment, the static pressure fluid support device 1 includes the fixed throttle 50 in the middle of the fluid supply channel 40. For this reason, fluid is always supplied into the static pressure pocket 20 at a constant pressure Pr (flow rate) corresponding to the supply pressure Ps of the fluid supply device 30 (pump P). An active variable throttle valve 70 is provided in the fluid discharge channel 60 connected to the static pressure pocket 20. The active variable throttle valve 70 has a clearance α between the guide surface 12a of the fixed table 12 (fixed body) and the guide surface 11a of the linear motion table 11 (moving body) detected by the displacement sensor 90 (gap detection unit). The pressure in the static pressure pocket 20, and thus the gap α between the guide surfaces 11a and 12a is controlled to be a predetermined gap α0.

  As described above, in the static pressure fluid support device 1, the pressure in the static pressure pocket 20 is mainly adjusted by the operation (opening / closing) of the active variable throttle valve 70 provided in the fluid discharge channel 60. That is, in a state that is not easily affected by the pressure on the fluid supply side, the pressure in the static pressure pocket 20 is adjusted, that is, the clearance α between the guide surface 12a of the fixed table 12 and the guide surface 11a of the linear motion table 11 is reduced. The size can be adjusted.

  In the active variable throttle valve 70, the fluid in the static pressure pocket 20 is discharged to the atmosphere side. Therefore, it is possible to easily set a large differential pressure between the upstream side and the downstream side of the active variable throttle valve 70 with respect to the atmospheric pressure. For this reason, since the fluid of a large flow rate can be discharged from the active variable throttle valve 70 in a short time, the pressure in the static pressure pocket 20 can be adjusted in a short time. Thereby, for example, when a negative disturbance load is generated and the pressure in the static pressure pocket 20 needs to be adjusted, the pressure in the static pressure pocket 20 is controlled by the active variable throttle valve 70. The thickness of the fluid film formed between the guide surfaces 11a and 12a can be adjusted to an appropriate size in a short time.

  Further, according to the first embodiment, the gap detection unit is the displacement sensor 90, and the displacement sensor 90 detects the gap α between the guide surfaces 11a and 12a formed by the fluid film. As described above, since the gap α is directly detected by the displacement sensor 90, the gap α between the guide surfaces 11a and 12a is controlled to be a predetermined gap α0 regardless of the fluctuation of the disturbance load.

  Further, according to the first embodiment, the active variable throttle valve 70 is disposed apart from the fixed table 12 and the linear motion table 11. Thereby, since the active variable throttle valve 70 can be assembled separately from the fixed table 12 and the direct acting table 11, any type of the fixed table 12 and the direct acting table 11 can be applied and is highly versatile. .

  Further, according to the first embodiment, the valve body of the valve portion 78 included in the active variable throttle valve 70 is the diaphragm 86. Thereby, the force generated by the actuator 71 is the force that operates the diaphragm 86 by the differential pressure between the first pressure P1 in the fluid storage chamber 87 and the second pressure P2 around the valve seat 89 in the fluid discharge chamber 88. The power removed is sufficient. Accordingly, the actuator 71 can be reduced in size and contributes to cost reduction.

(1-4. Modification of First Embodiment)
(1-4-1. Modification 1)
In the first embodiment, the gap α between the guide surfaces 11a and 12a is directly detected by the displacement sensor 90 (gap detection unit). However, the present invention is not limited to this mode. As a first modification (not shown), the gap α is detected based on the magnitude of the disturbance load that is detected in advance and the detected pressure Pr by directly detecting the pressure Pr (= P1) in the static pressure pocket 20 by the pressure sensor. It may be calculated and derived. Since the calculation method for deriving the gap α from the pressure Pr is well known, detailed description thereof is omitted.

(1-4-2. Modification 2)
In the first embodiment, the active variable throttle valve 70 is disposed away from the fixed table 12 and the linear motion table 11. However, it is not limited to this aspect. As a second modification of the first embodiment, as shown in FIG. 4, a valve portion 78 of an active variable throttle valve 70 is integrally fixed to the linear motion table 11 (active variable throttle valve 170). It may be. Other than the above, the second embodiment is the same as the first embodiment.

  In this case, the upper portion of the housing 181 included in the valve portion 178 includes an opening. The housing 181 is fixed to the linear motion table 11 (moving body) so that the opening of the housing 181 communicates with the static pressure pocket 20. With such a configuration, the fluid discharge channel 60 and the like are unnecessary, and the number of parts can be reduced.

<2. Second embodiment>
Next, a second embodiment will be described mainly based on FIG. The hydrostatic fluid support device 201 according to the second embodiment differs from the hydrostatic fluid support device 1 according to the first embodiment only in the active variable throttle valve 70 and the fixed throttle 50, and other configurations and operations are as follows. It is the same. Therefore, a different part from the static pressure fluid support apparatus 1 of 1st embodiment is mainly demonstrated in detail, and the description about many parts of a similar part is abbreviate | omitted. Similar components may be described with the same reference numerals.

  As shown in FIG. 5, the active variable throttle valve 270 included in the static pressure fluid support device 201 is connected to the end of a pipe 260 a that is a part of the fluid discharge channel 260 connected to the static pressure pocket 20. Yes. Specifically, a valve portion 278 provided in the active variable throttle valve 270 is connected to an end portion of the pipe 260a. Further, the active variable throttle valve 270 is disposed away from the linear motion table 11 (moving body) and the fixed table 12 (fixed body) downward in the gravity direction.

  As shown in FIG. 5, the active variable throttle valve 270 includes an actuator 271, a valve portion 278, and a connecting member 279. The valve portion 278 and the actuator 271 are formed separately. Further, the valve portion 278 is disposed adjacent to the actuator 271 in the vertical direction.

(2-1. Actuator)
The actuator 271 is a piezo-type actuator formed by stacking a plurality of known piezo elements 271a. The piezoelectric actuator 271 is extended in the total length in the stacking direction by increasing the voltage applied to the piezo element 271a.

(2-2. Valve part)
The valve unit 278 includes a housing 281. The valve portion 278 includes an inflow hole 282, an outflow hole 285, a poppet valve 286 (valve element), a fluid storage chamber 287, and a valve seat 289 in the housing 281. In the center of the valve seat 289, the outflow hole 285 described above as a through hole is formed. The outflow hole 285 is connected to one end of a pipe 260 b, which is the other part of the fluid discharge channel 260, at the outlet side opening 285 a.

  The other end of the pipe 260 b is connected to the drain part 21. In the second embodiment, the fluid discharged from the valve unit 278 is guided to the drain unit 21 by the fluid discharge channel 260 (pipe 260b). However, the present invention is not limited to this. If the fluid discharged from the valve portion 278 does not contact the actuator 271 disposed below the valve portion 278 in the gravity direction, it is not necessary to guide the fluid to the vicinity of the drain portion 21.

  The poppet valve 286 (valve element) is a known poppet valve, and is provided in the fluid storage chamber 287 so as to be movable in the vertical direction. Then, the poppet valve 286 is moved downward via the connecting member 279 by the operation of the actuator 271, so that the tapered seal portion comes into contact with the seal portion of the valve seat 289, thereby blocking the discharge of the fluid from the valve portion 278. To do. Further, when the poppet valve 286 moves upward via the connecting member 279 by the operation of the actuator 271, the opening of the throttle formed by the gap between the poppet valve 286 (valve element) and the valve seat 289 becomes large. Thereby, the fluid supplied to the fluid storage chamber 287 corresponds to the pressure difference between the pressure P3 (corresponding to the third pressure) in the fluid storage chamber 287 and the atmospheric pressure, and the size of the opening of the throttle (gap). The flow rate is discharged (discharged) from the throttle (gap) to the drain portion 21 via the outflow hole 285 and the fluid discharge channel 260 (pipe 260b).

  The connecting member 279 is formed in a straight line, inserted into the outflow hole 285 of the housing 281, one end connected to the upper end surface of the actuator 271, and the other end connected to the lower end of the poppet valve 286 (valve element). The When a voltage is applied to the piezoelectric element 271a of the actuator 271, the actuator 271 extends in the stacking direction. As a result, the poppet valve 286 (valve element) moves upward via the connecting member 279, and is changed in a direction in which the aperture of the throttle is increased.

  Further, when the voltage applied to the actuator 271 is lowered, the actuator 271 contracts in the stacking direction and returns to the initial state. As a result, the poppet valve 286 moves downward, the seal portion comes into contact with the seal portion of the valve seat 289, and the discharge of the fluid from the valve portion 278 is blocked. In this sealed state, the pressure of the fluid in the fluid storage chamber 287 also urges the poppet valve 286 downward to increase the sealing force, and contributes to blocking the discharge of fluid from the valve portion 278.

  At this time, the connecting member 279 is preferably connected to the lower end of the poppet valve 286 after being inserted into the pipe 260b connected to the outflow hole 285 from the middle of the pipe 260b and passing through the pipe. That is, as shown in FIG. 5, the connecting member 279 is inserted from below the bent portion of the pipe 260a bent into an L shape, and is inserted into one side of the pipe 260b extending in the vertical direction, and then passes through the outflow hole 285. Thus, it is preferably connected to the lower end of the poppet valve 286.

  At this time, at the L-shaped bent portion of the pipe 260a into which the connecting member 279 is inserted, the connecting member 279 can move relative to the pipe 260a in the vertical direction, and the fluid moving in the pipe 260b is connected. A predetermined sealing means is provided so as not to flow out of the pipe 260b from the insertion position of the member 279. At this time, any sealing means may be used. Accordingly, since the fluid does not contact the piezo-type actuator 271 that is feared to be used in a fluid such as oil from the viewpoint of durability, it can be used without worrying about durability.

(2-3. Fixed aperture)
Next, the fixed diaphragm 250 will be described. The fixed throttle 250 includes a large-diameter fixed throttle 251, a small-diameter fixed throttle 252, and a switching valve 253 that are two types of fixed throttles. The operation of the switching valve 253 is controlled by the control device 100. The fixed diaphragm 250 is arranged as shown in FIG. Before describing the fixed throttle 250, only a part of the active variable throttle valve 270 that has not been described above will be described.

  Although not shown, in the active variable throttle valve 270 in the second embodiment, when the power to the actuator 271 is interrupted, the poppet valve 286 (valve element) of the valve portion 278 is closed by a spring (not shown). It is a normally closed type variable throttle valve that is configured to be urged by the valve and to contact the valve seat 289 and close.

  Therefore, when the actuator 271 is energized, the poppet valve 286 (valve element) is pushed by the actuator 271 via the linear connecting member 279, and a spring (not shown) is compressed to separate from the valve seat 289 and open. During operation, the fluid in the fluid storage chamber 287 can be discharged from the throttle of the valve portion 278 to the drain portion 21. For this reason, even if the pressure of the fluid supplied to the static pressure pocket 20 and the fluid storage chamber 287 via the fixed throttle is relatively high, the fluid can be discharged to the drain portion 21 by the operation of the poppet valve 286 by the actuator 271. Therefore, the pressure of the fluid in the static pressure pocket 20 can be adjusted satisfactorily.

  As a result, the pressure in the static pressure pocket 20 and thus the gap α between the guide surfaces 11a and 12a can be well adjusted to a predetermined size. That is, at the time of normal operation, the large-diameter fixed throttle 251 formed with the same flow path diameter φD1 as the fixed throttle 50 applied in the first embodiment is applied.

  However, if a situation occurs where the energization to the actuator 271 is interrupted unintentionally (hereinafter referred to as an energization interruption), the poppet valve 286 (valve element) is maintained in the closed state and cannot move, and the fluid storage chamber The fluid in 287 cannot be discharged to the drain portion 21. For this reason, when the pressure of the fluid supplied to the static pressure pocket 20 via the fixed throttle is relatively high, the fluid pressure is maintained in a high state in the static pressure pocket 20 and the fluid storage chamber 287.

  Thereby, there exists a possibility that the clearance gap (alpha) between each guide surface 11a, 12a may be maintained by the excessive magnitude | size exceeding predetermined magnitude | size. For this reason, when the energization is cut off, the small-diameter fixed restrictor 252 formed with the channel diameter φD2 (φD1> φD2) smaller than the channel diameter φD1 of the fixed restrictor 50 applied in the first embodiment is applied. . Therefore, the switching valve 253 is used to switch between the large diameter fixed throttle 251 and the small diameter fixed throttle 252 according to the situation.

  The switching valve 253 is a known 4-port 2-position valve as shown in FIG. Therefore, detailed description is omitted. A fluid supply flow path 40 connected to the fluid supply device 30 is branched and connected to the two ports on the input side. A large-diameter fixed diaphragm 251 and a small-diameter fixed diaphragm 252 are connected to the two ports on the output side. FIG. 5 shows the state of the switching valve 253 during normal operation when the power is on. FIG. 6 shows the state of the switching valve 253 when the power is shut off.

  With the above configuration, when the switching valve 253 and the actuator 271 are energized during normal operation, the large-diameter fixed throttle 251 is applied as the fixed throttle of the fluid supply flow path 40 in the switching valve 253. When a disturbance load is generated in the static pressure fluid support portion, the control device 100 performs the same control as in the first embodiment, and the gap α between the guide surfaces 11a and 12a has a predetermined size. Actuator 271 is actuated.

  However, when the power supply to the switching valve 253 and the actuator 271 is shut off, the switching valve 253 is in the state shown in FIG. 6 by the urging of the spring 253a. Thereby, the small diameter fixed throttle 252 is applied as a fixed throttle of the fluid supply flow path 40. At this time, the power supply to the actuator 271 is also shut off. For this reason, as described above, the poppet valve 286 (valve element) is urged in the valve closing direction by a spring (not shown) and comes into contact with the valve seat 289 to be in a valve closing state. Therefore, the fluid in the fluid storage chamber 287 is not discharged to the drain portion 21.

  However, as described above, in the fluid supply channel 40, the switching valve 253 operates, and the small-diameter fixed throttle 252 is disposed as a fixed throttle of the fluid supply channel 40. For this reason, the fluid of excessive pressure is not supplied to the static pressure pocket 20. Therefore, the clearance α between the guide surfaces 11a and 12a is not excessive, and the reliability is ensured.

  In addition, in 2nd embodiment, about the operation | movement when the disturbance load at the time of normal operation arises in a static pressure fluid support part, the process similar to the flowchart of 1st process S10 to 4th process S40 in 1st embodiment is carried out. Just do it. However, unlike the first embodiment, the second embodiment will be described assuming that a negative disturbance load is applied between the guide surface 11a supported by the hydrostatic fluid and the guide surface 12a.

  When a negative disturbance force acts on the fluid film due to the negative disturbance load, for example, the thickness α of the fluid film becomes larger than the predetermined thickness α0 of the fluid film in the initial state. In the above, the negative disturbance load refers to a load in the direction in which the thickness of the fluid film increases. For convenience of explanation, the fluid film thickness α in the initial state will be described as a target predetermined gap α0 as in the first embodiment.

  In the first step S10, in the above state, the displacement sensor 90 (gap detection unit) detects the detection value k1 corresponding to the gap α between the guide surfaces 11a and 12a on which the fluid film is formed. In the second step S <b> 20, the sensor amplifier 101 amplifies the detection value k <b> 1 acquired from the displacement sensor 90 and transmits it to the controller 102. At this time, the size of the gap α detected by the displacement sensor 90 (gap detection unit) is larger than the predetermined gap α0 (= target gap) (α> α0).

  In other words, since a negative disturbance force is applied to the static pressure fluid support portion, the pressure in the static pressure pocket 20 becomes excessive to maintain the predetermined gap α0, and the gap α is larger than the predetermined gap α0. It is getting bigger. For this reason, the control device 100 needs to control to reduce the excess pressure in the static pressure pocket 20 and return the gap α to the predetermined gap α0.

  In the third step S30, the controller 102 calculates the difference k2 (= k0−k1) between the detected value k1 and the value k0 corresponding to the predetermined gap α0 between the guide surfaces 11a and 12a to be targeted, and the actuator Transmit to the drive unit 103. At this time, the predetermined gap α0 to be targeted is stored in the controller 102 in advance.

  In the fourth step S40, the actuator drive unit 103 generates a drive signal S1 for the actuator 271 based on the difference k2 calculated by the controller 102. Then, the actuator driving unit 103 outputs the generated drive signal S1 to the piezo element 271a of the actuator 271 and displaces the piezo element 271a upward, for example, by a displacement amount s (not shown) in FIG.

  Accordingly, the connecting member 279 connected to the piezo element 271a is displaced upward by a displacement amount s (not shown), and the valve part connected to the end of the connecting member 279 on the side opposite to the piezo element 271a side. The poppet valve 286 (valve element) 278 is displaced upward by a displacement amount s (not shown) following the upward movement of the connecting member 279.

  As a result, the restriction (gap) of the valve portion 278 is changed to the enlargement side (open side) restriction amount that is the desired restriction amount. For this reason, the flow rate of the fluid discharged from the valve part 278 to the drain part 21 after the change of the throttle amount is larger than the flow rate discharged from the valve part 278 to the drain part 21 in the initial state and flows out (discharged). The

  Therefore, the pressure Pr of the fluid supplied from the pump P to the static pressure pocket 20 through the large-diameter fixed restrictor 251 decreases as the flow rate of the fluid discharged from the valve portion 278 to the drain portion 21 increases. The size of the gap between the guide surfaces 11a and 12a is a target predetermined gap α0.

  As a result, even when a negative disturbance load is generated and the pressure in the static pressure pocket 20 needs to be adjusted, the pressure in the static pressure pocket 20 is adjusted to the magnitude of the disturbance load by the control of the active variable throttle valve 270. Accordingly, the thickness of the fluid film formed between the guide surfaces 11a and 12a can be adjusted to an appropriate size in a short time.

(2-4. Effects of Second Embodiment)
According to the second embodiment, the valve body of the valve portion 278 included in the active variable throttle valve 270 is the poppet valve 286, and the poppet valve 286 is displaced by the operation of the actuator 271, and the static pressure pocket 20 and the fluid are discharged. A fluid having a flow rate corresponding to the pressure difference between the third pressure P3 in the fluid storage chamber 287 of the valve portion 278 communicated via the flow path 260 and the atmospheric pressure as the pressure of the drain portion 21 is drained from the valve portion 278. It is discharged to the part 21. Thereby, the same effect as the active variable throttle valve 70 of the first embodiment can be expected.

  Further, according to the second embodiment, the active variable throttle valve 270 is configured such that the poppet valve 286 (valve element) of the valve portion 278 abuts on the valve seat 289 when energization to the actuator 271 is interrupted. It is a normally closed type variable throttle valve configured to close. The supply-side fixed diaphragm 250 is provided with two types, a large-diameter fixed diaphragm 251 and a small-diameter fixed diaphragm 252. In the normal operation in which the poppet valve 286 (valve element) of the active variable throttle valve 70 is separated from the valve seat 289 and is opened, the large-diameter fixed throttle 251 is applied, the power supply to the actuator 271 is cut off, and the valve portion 278 is cut off. In the non-normal operation in which the poppet valve 286 (valve element) contacts the valve seat 289 and closes, the small-diameter fixed throttle 252 is switched. As a result, during non-normal operation, a fluid having an excessive pressure is not supplied to the static pressure pocket 20, and the clearance α between the guide surfaces 11a and 12a is not excessive, so that reliability is ensured. The

  Further, according to the second embodiment, the actuator 271 of the active variable throttle valve 270 is formed by the piezo element 271a. Since the operation on the extension side of the piezo element 271a has a high speed and a high resolution, the gap α between the guide surfaces 11a and 12a can be changed quickly and accurately.

(2-5. Modification 1 of Second Embodiment)
Further, in the static pressure fluid support device 201 of the second embodiment, the active variable throttle valve 270 is disposed apart from the fixed table 12 (fixed body) and the linear motion table 11 (movable body). However, it is not limited to this aspect. As a first modification of the second embodiment, as shown in FIG. 7, a valve portion 278 of an active variable throttle valve 270 is integrally fixed to a linear motion table 11 (an active variable throttle valve 370). ). Other than the above, the second embodiment is the same as the second embodiment.

  In this case, the upper portion of the housing 381 provided in the valve portion 378 includes an opening. The housing 381 is fixed to the linear motion table 11 so that the opening of the housing 381 communicates with the static pressure pocket 20. With such a configuration, some of the pipes 260a and the like of the fluid discharge channel 260 are unnecessary, and the number of parts can be reduced.

  In the first and second embodiments, the static pressure fluid support devices 1,201 support the planar static pressure support surface of the fixed table 12. However, the present invention is not limited thereto, and a rotary shaft such as a spindle is used. You may support. When the rotating shaft is supported, high bearing rigidity can be given to disturbance loads by arranging the rotating shafts on the opposing bearing surfaces. In addition, when applying a static pressure fluid support apparatus to a rotating shaft, you may provide a static pressure pocket in any of a fixed body and a moving body. In addition to the rotating shaft, the present invention can also be applied to journal bearings, thrust bearings, and hydrostatic screws.

1, 201; Static pressure fluid support device, 11; Linear motion table (moving body), 11a, 12a; Guide surface, 12; Fixed table (fixed body), 20; Static pressure pocket, 21; Drain part, 30; 40, fluid supply flow path, 50, 250; fixed throttle, 60, 260; fluid discharge flow path, 70, 170, 270, 370; active variable throttle valve, 71, 271; actuator, 78, 178, 278, 378; valve part, 79, 279; connecting member, 85, 285; outflow hole, 86; diaphragm (valve element), 87, 287; fluid storage chamber, 88; fluid discharge chamber, 89, 289; valve seat, 90; displacement sensor (gap detection unit), 100; control device, 253; switching valve, 286; poppet valve (valve element), α, α0;

Claims (9)

A static pressure pocket provided on the guide surface of the movable body or fixed body;
A fluid supply device for supplying a pressurized fluid to the static pressure pocket;
A fluid supply flow path that forms a fluid passage from the fluid supply device to the static pressure pocket;
A fixed throttle on the supply side provided in the fluid supply channel;
A fluid discharge flow path that forms a fluid passage from the static pressure pocket to the drain portion;
An actuator, a valve portion including a valve body and a valve seat, and a connecting member that transmits the operation of the actuator to the valve body, wherein the valve portion is provided in the fluid discharge channel, and the valve is operated by the operation of the actuator. When the body is displaced via the connecting member, the throttle amount of the throttle formed between the valve body and the valve seat is changed, and the flow rate of the fluid discharged from the valve portion to the drain portion is changed. An active variable throttle valve on the discharge side to be adjusted;
A gap detection unit that detects a gap between the guide surface of the movable body and the guide surface of the fixed body;
The actuator is controlled according to the size of the gap detected by the gap detection unit, the displacement amount of the valve body of the active variable throttle valve is changed to adjust the throttle amount, and the exhaust is discharged from the valve unit. And a control device that changes the flow rate of the fluid and sets the gap between the guide surfaces to a predetermined size.   The static pressure fluid support device according to claim 1, wherein the gap detection unit detects the gap by a displacement sensor.   The static pressure fluid support device according to claim 1, wherein the active variable throttle valve is disposed apart from the movable body and the fixed body. The valve body of the valve portion provided in the active variable throttle valve is a diaphragm,
The diaphragm is
The actuation of the actuator;
In the valve portion, a first pressure in a fluid storage chamber formed on the first surface side of the diaphragm and communicated with the static pressure pocket via the fluid discharge channel, and a second surface of the diaphragm in the valve portion A pressure difference with the second pressure in the fluid discharge chamber of the valve portion formed on the side and communicated with the drain portion, and is displaced by applying a biasing force;
The fluid having a flow rate corresponding to a pressure difference between the second pressure in the fluid discharge chamber after the displacement of the diaphragm and an atmospheric pressure that is a pressure of the drain portion is discharged from the valve portion to the drain portion. The hydrostatic fluid support device according to any one of claims 1 to 3. When the energization to the actuator of the active variable throttle valve is cut off,
The diaphragm is
The operating force of the actuator is canceled, and the biasing force is applied only by the pressure difference between the first pressure in the fluid storage chamber and the second pressure in the fluid discharge chamber, and the actuator can be displaced.
The static pressure fluid support device according to claim 4, wherein the fixed throttle on the supply side is the fixed throttle that is applied when power to the actuator is not cut off. The valve body of the valve portion provided in the active variable throttle valve is a poppet valve,
The poppet valve is
Displaced by the actuation of the actuator;
The fluid having a flow rate corresponding to a pressure difference between a third pressure in the fluid storage chamber of the valve portion communicated with the static pressure pocket and the fluid discharge channel and an atmospheric pressure which is a pressure of the drain portion. The hydrostatic fluid support device according to claim 1, wherein the static pressure fluid support device is discharged from the valve portion to the drain portion. The active variable throttle valve is
When the energization to the actuator is interrupted, the valve body of the valve portion is a normally closed type variable throttle valve configured to close in contact with the valve seat,
The fixed throttle on the supply side is
There are two types, a large diameter fixed throttle and a small diameter fixed throttle.
The large diameter fixed throttle is applied during normal operation in which the valve body of the active variable throttle valve is separated from the valve seat and opened,
The hydrostatic fluid support device according to claim 6, wherein in the non-normal operation in which energization to the actuator is interrupted and the valve body of the valve portion contacts and closes the valve seat, the static pressure fluid support device is switched to the small-diameter fixed throttle. .   The static pressure fluid support device according to claim 6 or 7, wherein the actuator of the active variable throttle valve is formed by a piezo element.   The hydrostatic fluid support device according to any one of claims 1 to 8, wherein the actuator of the active variable throttle valve is disposed at a predetermined position in the atmosphere that does not contact the fluid.

Images