JP6937165B2 - Servo valve and fluid system - Google Patents

Description

The present invention relates to a servo valve and a fluid device having high response performance.

Servo valves are used in aircraft and other industrial fields. Patent Document 1 discloses a technique of displacing a nozzle left and right with respect to a rotation axis based on an electromagnetic principle to adjust the amount of hydraulic oil flowing into two inlets formed in a receiver.

U.S. Pat. No. 2884907

The high response speed of the servo valve results in the high accuracy of control using the servo valve. Therefore, conventionally, various improvements have been made to the mechanical and / or electrical mechanism for driving the nozzle. However, many of these improvements face various challenges such as material selection, mechanical strength, control complexity and servo valve manufacturing costs.

An object of the present invention is to provide a simple technique for giving a high response speed to a servo valve.

The servo valve according to one aspect of the present invention uses a fluid to drive an actuator. The servo valve includes a nozzle including a discharge edge forming the contour of the discharge port from which the fluid is discharged, a tapered inner wall narrowing toward the discharge edge, and a flow into which the fluid discharged from the discharge port flows. It comprises a receiver on which a road is formed. The nozzle is displaced in a direction different from the discharge direction in which the fluid is discharged. The extending direction of the flow path is inclined at an angle α with respect to the direction orthogonal to the inflow surface facing the nozzle. The taper angle defined by the tapered inner wall is larger than twice the angle α.

According to the above configuration, the taper angle determined by the tapered inner wall is larger than twice the angle α, so that the component force of the force (also referred to as “flow force”) that the tapered inner wall receives from the fluid in the displacement direction of the nozzle is. It becomes smaller. Since the nozzle can be quickly displaced with little influence from the fluid, the working fluid can be switched quickly, so that the servo valve can operate at a high response speed and drive the actuator quickly. ..

The servo valve according to another aspect of the present invention is a servo valve that drives an actuator using a fluid, and narrows toward the discharge edge forming the contour of the discharge port from which the fluid is discharged and the discharge edge. A nozzle including a tapered inner wall, a first inflow port into which a part of the fluid discharged from the discharge port flows in, and a second inflow port into which another part of the fluid discharged from the discharge port flows in. A receiver including an inflow surface in which the nozzle is formed, and a drive unit for driving the nozzle along an alignment line in which the first inflow port and the second inflow port are aligned are provided. The drive unit is displaced on the alignment line from a neutral position where an extension line extending from the center of the discharge port in the discharge direction of the fluid intersects the alignment line between the first inlet and the second inlet. The nozzle is driven so as to do so. The virtual plane that includes the extension line and the alignment line and the tapered inner wall form a straight first line of intersection and a straight second line of intersection. When the nozzle is in the neutral position, the extension line of the first line of intersection extends into the first inlet, and the extension line of the second line of intersection extends into the second inlet.

According to the above configuration, when the nozzle is in the neutral position, the extension line of the first line of intersection extends into the first inlet, and the extension line of the second line of intersection extends into the second inlet, so that it is tapered. The taper angle of the inner wall becomes large. Therefore, the component force of the flow force received from the fluid by the tapered inner wall in the direction along the alignment line becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

The fluid system according to still another aspect of the present invention includes the above-mentioned servo valve and a movable piece displaced by the fluid in an air chamber communicating with the first outlet and the second outlet.

According to the above configuration, since the fluid device has the above-mentioned servo valve, it can operate at a high response speed.

The techniques described above can provide high response speeds to servo valves and fluid systems.

It is a conceptual diagram of the servo valve of 1st Embodiment. It is streamline data in the conventional servo valve (second embodiment). FIG. 1 is a diagram showing a centrifugal force (flow force) acting on the line of intersection defined on FIG. 1 (second embodiment). It is a figure which shows the centrifugal force (flow force) acting on the line segment which has a gradient larger than the intersection line shown in FIG. 3A (second embodiment). It is a conceptual diagram of the servo valve of the 3rd Embodiment. It is a conceptual diagram of the servo valve of 4th Embodiment. It is a conceptual diagram of the servo valve of the 5th Embodiment. It is a conceptual diagram of the servo valve of the sixth embodiment. It is the schematic of the fluid apparatus of 7th Embodiment. It is a contour line diagram which shows the pressure distribution of the working fluid around the discharge port (8th Embodiment). It is a contour line diagram which shows the pressure distribution of the working fluid around the discharge port (8th Embodiment). It is a contour line diagram which shows the pressure distribution of the working fluid around the discharge port (8th Embodiment). It is a graph which shows the relationship between the relative position of a nozzle with respect to a receiver, the flow rate of a working fluid discharged from a nozzle, and the force which a nozzle receives from a working fluid (taper angle = 0 °) (8th Embodiment). It is a graph which shows the relationship between the relative position of a nozzle with respect to a receiver, the flow rate of a working fluid discharged from a nozzle, and the force which a nozzle receives from a working fluid (taper angle: small) (8th Embodiment). It is a graph which shows the relationship between the relative position of a nozzle with respect to a receiver, the flow rate of a working fluid discharged from a nozzle, and the force which a nozzle receives from a working fluid (taper angle: large) (8th Embodiment). It is a figure for demonstrating the relationship between the pressure gradient of the working fluid and the flow force in the vicinity of the discharge port of a nozzle. It is a figure which illustrates the relationship between the pressure gradient of a working fluid, the inclination angle α of a flow path, and the taper angle β of a nozzle.

<First Embodiment>
With respect to the conventional servo valve, the tip of the nozzle swirls (swings) in both directions within a predetermined angle range about the rotation axis (hereinafter, also referred to as "swaying motion" or "swinging motion"). It is designed to be. The present inventors have found a problem that the pressure applied to the inner wall surface of the nozzle by the working fluid discharged from the nozzle acts as a drag against the left and right shaking motion. The large drag against the shaking motion hinders the motion of switching the flow of the working fluid, and as a result, the response performance of the servo valve and the actuator connected to the servo valve is deteriorated. In the first embodiment, an exemplary servo valve capable of reducing drag against the shaking motion of the nozzle will be described.

FIG. 1 is a conceptual diagram of the servo valve 100 of the first embodiment. The servo valve 100 will be described with reference to FIG. In the present embodiment, terms such as "top", "bottom", "left", "right", "clockwise", "counterclockwise", "vertical", and "horizontal" are clarified. Used only for the purpose. The principles of this embodiment are not limited by the terms used to describe these directions.

The servo valve 100 includes a nozzle 200 and a receiver 300. The nozzle 200 can be shaken clockwise and counterclockwise around the rotation axis RAX defined on the upper part of the nozzle 200. The nozzle 200 shown in FIG. 1 is in the "neutral position". In the neutral position, the centerline of the nozzle 200 coincides with the vertical line VL.

The nozzle 200 includes an upper surface 210 and a lower surface 220. The lower surface 220 faces the receiver 300. The upper surface 210 is located above the lower surface 220. An inflow port 211 is formed on the upper surface 210. The inflow port 211 is connected to a pump or other fluid source that supplies the working fluid. A hydraulic fluid (eg, but not limited to, hydraulic fluid; hereinafter, also simply referred to as “fluid”) flows into the nozzle 200 through the inflow port 211.

A discharge port 221 is formed on the lower surface 220 (tip surface) to discharge the working fluid flowing in from the inflow port 211. The center line of the nozzle 200 may be defined as a straight line passing through the center of the inflow port 211 and the center of the discharge port 221.

The lower surface 220 includes a discharge edge 222 that forms the contour of the discharge port 221. The discharge edge 222 may have a circular contour or a non-circular contour. The principle of this embodiment is not limited to the specific contour shape drawn by the discharge edge 222.

The nozzle 200 is formed with a nozzle flow path 230 extending downward from the inflow port 211 and connecting to the discharge port 221. The nozzle flow path 230 includes a straight pipe portion 231 and a tapered pipe portion 232 extending downward from the straight pipe portion 231. The straight pipe portion 231 extends along the center line of the nozzle 200 with a substantially constant cross-sectional area. The tapered pipe portion 232 narrows toward the discharge edge 222. The discharge pressure of the working fluid is increased by the tapered pipe portion 232. The high-pressure working fluid is discharged from the discharge port 221. When the nozzle 200 is in the neutral position, the discharge direction of the working fluid from the discharge port 221 substantially coincides with the extension direction of the vertical line VL. When the nozzle 200 is shaken clockwise, the discharge direction of the working fluid from the discharge port 221 becomes the lower left. When the nozzle 200 is shaken counterclockwise, the discharge direction of the working fluid from the discharge port 221 becomes the lower right. In the present embodiment, the first direction is exemplified by the discharge direction of the working fluid from the discharge port 221 of the nozzle 200 in the neutral position.

The nozzle 200 includes a tapered inner wall 240 that forms the contour of the tapered tube portion 232. The discharge edge 222 is located at the boundary between the tapered inner wall 240 and the lower surface 220.

The receiver 300 includes an upper surface 310 facing the lower surface 220 of the nozzle 200. A left inflow port 311 and a right inflow port 312 are formed on the upper surface 310. The left inflow port 311 is located to the left of the right inflow port 312. The alignment direction of the left inflow port 311 and the right inflow port 312 is substantially perpendicular to the discharge direction of the working fluid discharged from the discharge port 221 of the nozzle 200 in the neutral position. The alignment direction of the left inflow port 311 and the right inflow port 312 coincides with the moving direction of the discharge port 221 accompanying the rotation of the nozzle 200 around the rotation axis RAX. In the present embodiment, the second direction is exemplified by the alignment direction of the left inflow port 311 and the right inflow port 312 and / or the moving direction of the discharge port 221 accompanying the rotation of the nozzle 200 around the rotation axis RAX.

The receiver 300 is formed with a left flow path 313 and a right flow path 314. The left flow path 313 extends downward to the left from the left inflow port 311 and terminates at the left outflow port 315. The right flow path 314 extends downward to the right from the right inflow port 312 and terminates at the right outflow port 316. The left flow path 313 has a point-symmetrical relationship with respect to the right flow path 314 around the vertical line VL. The left outlet 315 and the right outlet 316 are formed on the outer surface of the receiver 300 and are connected to a spool valve (not shown) or an actuator (not shown).

When the nozzle 200 is in the neutral position, the working fluid discharged from the discharge port 221 flows into the left inflow port 311 and the right inflow port 312 substantially evenly. In this embodiment, the first flow path is exemplified by one of the left flow path 313 and the right flow path 314. The second flow path is exemplified by the other of the left flow path 313 and the right flow path 314. The first inlet is exemplified by one of the left inlet 311 and the right inlet 312. The second inlet is exemplified by the other of the left inlet 311 and the right inlet 312. The inflow surface is exemplified by the upper surface of the receiver 300.

FIG. 1 shows the center line CL of the left flow path 313. The extension direction of the center line CL coincides with the extension direction of the left flow path 313. FIG. 1 further shows the inclination angle α (<90 °) of the center line CL from the vertical line VL. As described above, since the right flow path 314 has a point-symmetrical relationship with the left flow path 313, the inclination angle of the center line (not shown) of the right flow path 314 from the vertical line VL is that of the left flow path 313. It corresponds to the tilt angle α. In this embodiment, the extension line is exemplified by the vertical line VL.

FIG. 1 shows the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312. The relative positional relationship between the nozzle 200 and the receiver 300 is set so that the vertical line VL and the center points LCP and RCP are located on a common virtual plane. FIG. 1 conceptually represents a cross section of a nozzle 200 and a receiver 300 on a common virtual plane. In this embodiment, the alignment line is exemplified by a straight line passing through the center points LCP and RCP.

FIG. 1 shows two lines of intersection LIS and RIS formed by the above-mentioned virtual plane and the tapered inner wall 240. The line of intersection LIS is formed to the left of the vertical line VL. The line of intersection RIS is formed to the right of the vertical line VL. The two lines of intersection LIS and RIS are straight line segments having a point-symmetrical relationship around the vertical line VL. FIG. 1 further shows the taper angle β of the tapered pipe portion 232. The taper angle β may be defined as an angle between the extension lines of the two lines of intersection LIS and RIS (intersection angle defined by the lines of intersection LIS and RIS). The taper angle β is determined so that the relationship shown in the following equation (1) is established. “2α” in the following equation (1) corresponds to the sandwiching angle between the left flow path 313 and the right flow path 314. In this embodiment, the first line of intersection is exemplified by one of the lines of intersection LIS and RIS. The second line of intersection is exemplified by the other of the lines of intersection LIS and RIS.

<Second Embodiment>
The angular relationship described in connection with the first embodiment contributes to the reduction of drag in the direction of movement of the nozzle. In the second embodiment, the principle of reducing drag is explained.

FIG. 2 shows streamline data in a conventional servo valve. A streamline generated in a conventional servo valve will be described with reference to FIG.

FIG. 2 shows a nozzle NZL and a receiver RCV arranged below the nozzle NZL. In FIG. 2, the left flow path LFP and the right flow path RFP formed in the receiver RCV are drawn. In FIG. 2, the tapered inner wall TIW of the nozzle NZL and the tapered flow path TFT surrounded by the tapered inner wall TIW are further drawn. The left flow path LFP, the right flow path RFP, the tapered flow path TFP, and the numerous curves drawn in the gap extending horizontally between the nozzle NZL and the receiver RCV represent the streamlines of the working fluid.

FIG. 2 shows a vertical line VL passing through a branch point between the left flow path LFP and the right flow path RFP. The nozzle NZL shown in FIG. 2 is moving to the left from the neutral position, and the working fluid discharged from the nozzle NZL through the tapered flow path TFP mainly flows into the left flow path LFP. At this time, the streamline of the working fluid from the tapered flow path TFP to the left flow path LFP curves to the left. The curvature of the streamline to the left means the generation of centrifugal force acting to the right with respect to the tapered inner wall TIW. The following equation (2) expresses the relationship between the pressure (left side) generated by centrifugal force and the radius of the curved streamline.

FIG. 3A shows the centrifugal force CF1 acting on the line of intersection RIS. FIG. 3B shows the centrifugal force CF2 acting on the line segment SGL having a gradient larger than the line of intersection RIS. The relationship between the taper angle and the centrifugal force will be described with reference to FIGS. 1, 3A and 3B.

As described above, when the nozzle 200 moves to the left, the centrifugal force CF1 acts on the line of intersection RIS on the tapered inner wall 240 due to the curvature of the streamline. The centrifugal force CF1 scalar shown in FIG. 3A is equal to the centrifugal force CF2 scalar shown in FIG. 3B. The centrifugal force CF1 is perpendicular to the line of intersection RIS. The centrifugal force CF2 is perpendicular to the line segment SGL.

FIG. 3A shows the horizontal component force HF1 of the centrifugal force CF1 and the vertical component force VF1 of the centrifugal force CF1. The horizontal component force HF1 is in the direction opposite to the moving direction (left) of the nozzle 200. Therefore, the horizontal component force HF1 acts as a drag against the left movement of the nozzle 200.

FIG. 3B shows the horizontal component force HF2 of the centrifugal force CF2 and the vertical component force VF2 of the centrifugal force CF2. The horizontal component force HF2 is larger than the horizontal component force HF1. This means that if the taper angle β is a large value, the drag force in the moving direction of the nozzle 200 becomes small. According to the present inventors, if the taper angle β is set so that the relationship represented by the inequality described in relation to the first embodiment is established, the servo valve 100 is a conventional servo valve. Can have higher response performance. For example, the taper angle β may be set to 90 ° or more.

<Third Embodiment>
The taper angle of the nozzle may be determined based on a pair of inlets formed in the receiver. In the third embodiment, a method of determining the taper angle based on the pair of inlets formed in the receiver will be described.

FIG. 4 is a conceptual diagram of the servo valve 100A of the third embodiment. The servo valve 100A will be described with reference to FIG. The description of the first embodiment is incorporated by reference to the elements with the same reference numerals as those of the first embodiment. In the present embodiment, terms such as "top", "bottom", "left", "right", "clockwise", "counterclockwise", "vertical", and "horizontal" are clarified. Used only for the purpose. The principles of this embodiment are not limited by the terms used to describe these directions.

Similar to the first embodiment, the servo valve 100A includes a nozzle 200 and a receiver 300. The description of the first embodiment is incorporated into these elements.

The servo valve 100A further includes a drive unit 400. The drive unit 400 shakes the nozzle 200 around the rotation shaft RAX. The drive unit 400 may be a general torque motor that applies a rotational force to the nozzle 200 by using an electromagnetic force, or may be another drive device. The principle of this embodiment is not limited to the specific device used as the drive unit 400.

The nozzle 200 shown in FIG. 4 is in the neutral position. FIG. 4 shows the intersection ISP between the center line of the nozzle 200 in the neutral position and the upper surface 310 of the receiver 300. The intersection ISP is located on a straight line passing through the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312.

When the nozzle 200 is shaken clockwise from the neutral position by the drive unit 400, the discharge port 221 moves to the left. During this time, the intersection ISP moves along a straight line passing through the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312, and approaches the center point LCP of the left inflow port 311. As a result, the working fluid mainly flows into the left inflow port 311. As described in connection with the second embodiment, while the working fluid mainly flows into the left inflow port 311 the horizontal component of the centrifugal force of the working fluid acting on the crossing line RIS is the crossing line. It becomes larger than the horizontal component of the centrifugal force of the working fluid acting on LIS.

When the nozzle 200 is shaken counterclockwise from the neutral position by the drive unit 400, the discharge port 221 moves to the right. During this time, the intersection ISP moves along a straight line passing through the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312, and approaches the center point RCP of the right inflow port 312. As a result, the working fluid mainly flows into the right inflow port 312. As described in connection with the second embodiment, while the working fluid mainly flows into the right inflow port 312, the horizontal component of the centrifugal force of the working fluid acting on the intersection line LIS is the intersection line. It becomes larger than the horizontal component of the centrifugal force of the working fluid acting on the RIS. In this embodiment, the flow force is exemplified by the horizontal component of the centrifugal force of the working fluid.

FIG. 4 shows the extension lines LEX and REX extending from the lower ends of the intersection lines LIS and RIS toward the receiver 300. The taper angle β may be determined so that the extension line LEX extends into the right inflow port 312 and the extension line REX extends into the left inflow port 311. Since the taper angle β is larger than the taper angle of the conventional nozzle, the horizontal component force applied to the lines of intersection LIS and RIS is smaller than that of the conventional nozzle.

<Fourth Embodiment>
With respect to the above-described embodiment, the shape of the tapered tube portion is a truncated cone having a straight generatrix. Alternatively, the shape of the tapered tube may be spherical or ellipsoidal. In this case, the tapered inner wall draws a curved contour on a virtual plane that includes the center of the left inflow port, the center of the right inflow port, and the center of the discharge port. The design principles described in connection with the third embodiment are also applicable to nozzles having tapered inner walls that delineate curved contours on a virtual plane. In a fourth embodiment, an exemplary servo valve comprising a nozzle with a tapered inner wall that outlines a curve on a virtual plane will be described.

FIG. 5 is a conceptual diagram of the servo valve 100B of the fourth embodiment. The servo valve 100B will be described with reference to FIG. The description of the third embodiment is incorporated by reference to the elements with the same reference numerals as those of the third embodiment. In the present embodiment, terms such as "top", "bottom", "left", "right", "clockwise", "counterclockwise", "vertical", and "horizontal" are clarified. Used only for the purpose. The principles of this embodiment are not limited by the terms used to describe these directions.

Similar to the third embodiment, the servo valve 100B includes a receiver 300 and a drive unit 400. The description of the third embodiment is incorporated into these elements.

The servo valve 100B further includes a nozzle 200B. Similar to the third embodiment, the nozzle 200B includes an upper surface 210 and a lower surface 220. The description of the third embodiment is incorporated into these elements.

A nozzle flow path 230B is formed in the nozzle 200B. The nozzle flow path 230B extends downward from the inflow port 211 formed on the upper surface 210 and connects to the discharge port 221 formed on the lower surface 220. Similar to the third embodiment, the nozzle flow path 230B includes a straight pipe portion 231. The description of the third embodiment is referred to the straight pipe portion 231.

The nozzle flow path 230B further includes a tapered tube portion 232B. The tapered pipe portion 232B extends downward from the straight pipe portion 231 and opens at the discharge port 221. The tapered pipe portion 232B is a semi-elliptical spherical shape that narrows toward the discharge port 221. The discharge pressure of the working fluid is increased by the tapered pipe portion 232B. The high-pressure working fluid is discharged from the discharge port 221. When the nozzle 200B is in the neutral position, the discharge direction of the working fluid from the discharge port 221 substantially coincides with the vertical line VL. When the nozzle 200B is shaken clockwise, the discharge direction of the working fluid from the discharge port 221 becomes the lower left. When the nozzle 200B is shaken counterclockwise, the discharge direction of the working fluid from the discharge port 221 becomes the lower right.

The nozzle 200B includes a tapered inner wall 240B that forms the contour of the tapered tube portion 232B. The discharge edge 222 is located at the boundary between the tapered inner wall 240B and the lower surface 220.

FIG. 5 shows the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312. The relative positional relationship between the nozzle 200B and the receiver 300 is set so that the vertical line VL and the center points LCP and RCP are located on a common virtual plane. FIG. 5 conceptually represents a cross section of the nozzle 200B and the receiver 300 on a common virtual plane.

FIG. 5 shows two lines of intersection LIC and RIC formed by the above-mentioned virtual plane and the tapered inner wall 240B. The line of intersection LIC is formed to the left of the vertical line VL. The line of intersection RIC is formed to the right of the vertical line VL. The two lines of intersection LIC and RIC are curves having a point-symmetrical relationship around the vertical line VL. In the present embodiment, the first line of intersection is exemplified by one of the line of intersection LIC and RIC. The second line of intersection is exemplified by the other of the lines of intersection LIC and RIC.

FIG. 5 shows the tangents LTG and RTG with respect to the intersection lines LIC and RIC. The tangent LTG is between the upper end of the line of intersection LIC (that is, the end located at the boundary between the tapered pipe portion 232 and the straight pipe portion 231) and the discharge edge 222 corresponding to the lower end of the line of intersection LIC. At the midpoint, it touches the line of intersection LIC. The tangent RTG is between the upper end of the line of intersection RIC (that is, the end located at the boundary between the tapered pipe portion 232 and the straight pipe portion 231) and the discharge edge 222 corresponding to the lower end of the line of intersection RIC. At the midpoint, it touches the line of intersection RIC. The taper angle β may be defined as the intersection angle of the tangent LTG and RTG.

The taper angle β may be determined such that the tangent LTG extends into the right inflow port 312 and the tangent RTG extends into the left inflow port 311 when the nozzle 200B is in the neutral position. Since the taper angle β is larger than the taper angle of the conventional nozzle, the horizontal component force applied to the line of intersection LIC and RIC is smaller than that of the conventional nozzle.

<Fifth Embodiment>
With respect to the above-described embodiment, the tapered tube portion is formed at the lower end of the nozzle. However, the tapered tube portion may be formed at other positions. In the fifth embodiment, an exemplary servo valve including a nozzle in which a straight pipe portion is formed under the tapered pipe portion will be described.

FIG. 6 is a conceptual diagram of the servo valve 100C of the fifth embodiment. The servo valve 100C will be described with reference to FIG. The description of the above-described embodiment is incorporated by reference to the elements with the same reference numerals as those of the above-described embodiment. In the present embodiment, terms such as "top", "bottom", "left", "right", "clockwise", "counterclockwise", "vertical", and "horizontal" are clarified. Used only for the purpose. The principles of this embodiment are not limited by the terms used to describe these directions.

Similar to the fourth embodiment, the servo valve 100C includes a receiver 300 and a drive unit 400. The description of the fourth embodiment is incorporated into these elements.

The servo valve 100C further includes a nozzle 200C. Similar to the fourth embodiment, the nozzle 200C includes an upper surface 210 and a lower surface 220. The description of the fourth embodiment is incorporated into these elements.

A nozzle flow path 230C is formed in the nozzle 200C. The nozzle flow path 230C extends downward from the inflow port 211 formed on the upper surface 210 and connects to the discharge port 221 formed on the lower surface 220. Similar to the fourth embodiment, the nozzle flow path 230C includes a straight pipe portion 231. The description of the fourth embodiment is referred to the straight pipe portion 231.

The nozzle flow path 230C further includes a tapered pipe portion 232C and a lower pipe portion 233. The tapered pipe portion 232C narrows downward from the straight pipe portion 231 and connects to the lower pipe portion 233. The lower pipe portion 233 extends downward from the tapered pipe portion 232C and opens at the discharge port 221. Unlike the tapered pipe portion 232C, the lower pipe portion 233 is a straight pipe. The discharge pressure of the working fluid is increased by the tapered pipe portion 232C. The working fluid is then slightly rectified by the lower pipe portion 233 and discharged from the discharge port 221. When the nozzle 200C is in the neutral position, the discharge direction of the working fluid from the discharge port 221 substantially coincides with the vertical line VL. When the nozzle 200C is shaken clockwise, the discharge direction of the working fluid from the discharge port 221 becomes the lower left. When the nozzle 200C is shaken counterclockwise, the discharge direction of the working fluid from the discharge port 221 becomes the lower right.

The nozzle 200C includes a tapered inner wall 240C and a lower pipe wall 250. The tapered inner wall 240C forms the contour of the tapered pipe portion 232C. The lower pipe wall 250 extends downward from the tapered inner wall 240C and terminates at the discharge edge 222. The lower pipe wall 250 forms the contour of the lower pipe portion 233.

FIG. 6 shows the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312. The relative positional relationship between the nozzle 200C and the receiver 300 is set so that the vertical line VL and the center points LCP and RCP are located on a common virtual plane. FIG. 6 conceptually represents a cross section of the nozzle 200C and the receiver 300 on a common virtual plane.

FIG. 6 shows two lines of intersection LIS and RIS formed by the above-mentioned virtual plane and the tapered inner wall 240C. The line of intersection LIS is formed to the left of the vertical line VL. The line of intersection RIS is formed to the right of the vertical line VL. The two lines of intersection LIS and RIS are curves having a point-symmetrical relationship around the vertical line VL.

FIG. 4 shows the extension lines LEX and REX extending from the lower ends of the intersection lines LIS and RIS toward the receiver 300. The taper angle β may be determined so that the extension line LEX extends into the right inflow port 312 and the extension line REX extends into the left inflow port 311. Since the taper angle β is larger than the taper angle of the conventional nozzle, the horizontal component force applied to the lines of intersection LIS and RIS is smaller than that of the conventional nozzle.

A force in the direction opposite to the moving direction of the nozzle 200C acts on the lower pipe wall 250. Therefore, the axial length dimension of the lower pipe portion 233 is determined so that the force in the direction opposite to the moving direction of the nozzle 200C does not become excessively large. The axial length dimension of the lower pipe portion 233 may be shorter than that of the tapered pipe portion 232C.

<Sixth Embodiment>
Under the design principles of the embodiments described above, excessively high resistance to the working fluid may be applied around the outlet. In a sixth embodiment, an exemplary servo valve comprising a nozzle having a conduit structure that reduces resistance around the discharge port will be described.

FIG. 7 is a conceptual diagram of the servo valve 100D of the sixth embodiment. The servo valve 100D will be described with reference to FIG. The description of the above-described embodiment is incorporated by reference to the elements with the same reference numerals as those of the above-described embodiment. In the present embodiment, terms such as "top", "bottom", "left", "right", "clockwise", "counterclockwise", "vertical", and "horizontal" are clarified. Used only for the purpose. The principles of this embodiment are not limited by the terms used to describe these directions.

Similar to the fifth embodiment, the servo valve 100D includes a receiver 300 and a drive unit 400. The description of the fifth embodiment is incorporated into these elements.

The servo valve 100D further includes a nozzle 200D. Similar to the fifth embodiment, the nozzle 200D includes an upper surface 210 and a lower surface 220. The description of the fifth embodiment is incorporated into these elements.

A nozzle flow path 230D is formed in the nozzle 200D. The nozzle flow path 230D extends downward from the inflow port 211 formed on the upper surface 210 and connects to the discharge port 221 formed on the lower surface 220. Similar to the fifth embodiment, the nozzle flow path 230D includes a straight pipe portion 231 and a tapered pipe portion 232C. The description of the fifth embodiment is incorporated into these elements.

The nozzle flow path 230D further includes a lower tube portion 233D. The lower pipe portion 233D narrows upward from the discharge port 221 and is connected to the lower end of the tapered pipe portion 232C. Unlike the fifth embodiment, the cross section of the lower pipe portion 233D increases downward. Therefore, the resistance acting on the working fluid around the discharge port 221 does not become excessively large.

The nozzle 200D includes a lower tube wall 250D. The tapered inner wall 240C forms the contour of the tapered pipe portion 232C. The lower tube wall 250D extends downward from the tapered inner wall 240C and terminates at the discharge edge 222. The lower pipe wall 250D forms the contour of the lower pipe portion 233D.

A force in the direction opposite to the moving direction of the nozzle 200D acts on the lower pipe wall 250D. Therefore, the axial length dimension of the lower pipe portion 233D is determined so that the force in the direction opposite to the moving direction of the nozzle 200D does not become excessively large. The axial length dimension of the lower pipe portion 233D may be shorter than that of the tapered pipe portion 232C.

<7th Embodiment>
The servo valves described in connection with the embodiments described above can be incorporated into various fluid devices driven by a working fluid. In the seventh embodiment, an exemplary fluid system will be described.

FIG. 8 is a schematic view of the fluid system 500 of the seventh embodiment. The fluid system 500 will be described with reference to FIGS. 4 and 8. The description of the third embodiment is incorporated by reference to the elements with the same reference numerals as those of the third embodiment.

The fluid system 500 includes a servo valve 100E, an actuator 600, two pumps 510 and 520, and a tank 530. Similar to the third embodiment, the servo valve 100E includes the receiver 300. The description of the third embodiment is incorporated in the receiver 300. The tilt angles of the left flow path 313 and the right flow path 314 formed in the receiver 300 are determined based on the design principles described in connection with the above embodiments.

The servo valve 100E includes a torque motor 400E. The torque motor 400E corresponds to the drive unit 400 described with reference to FIG. The description of the drive unit 400 is incorporated in the torque motor 400E.

The torque motor 400E includes a lower coil 411, an upper coil 412, a lower magnetic pole piece 421, an upper magnetic pole piece 422, and a magnetic rod 430. The upper coil 412 is arranged above the lower coil 411. The lower magnetic pole piece 421 may be formed in a substantially cylindrical shape. The lower coil 411 is housed in the lower magnetic pole piece 421. Similar to the lower magnetic pole piece 421, the upper magnetic pole piece 422 may be formed in a substantially cylindrical shape. The upper coil 412 is arranged in the upper magnetic pole piece 422. The lower edge of the upper magnetic pole piece 422 faces the upper edge of the lower magnetic pole piece 421. The magnetic rod 430 extends substantially horizontally. The left and right ends of the magnetic rod 430 are located in the gap between the upper edge of the lower magnetic pole piece 421 and the lower edge of the upper magnetic pole piece 422.

A current is supplied to the lower coil 411 and the upper coil 412. As a result, the lower magnetic pole piece 421 and the upper magnetic pole piece 422 function as magnets. When current is supplied to the lower coil 411 and the upper coil 412 so that the right end of the magnetic rod 430 is attracted to the lower magnetic pole piece 421 while the left end of the magnetic rod 430 is attracted to the upper magnetic pole piece 422. The magnetic rod 430 rotates clockwise. When current is supplied to the lower coil 411 and the upper coil 412 so that the left end of the magnetic rod 430 is attracted to the lower magnetic pole piece 421 while the right end of the magnetic rod 430 is attracted to the upper magnetic pole piece 422. The magnetic rod 430 rotates counterclockwise.

The servo valve 100E includes a nozzle portion 200E. The nozzle portion 200E corresponds to the nozzle 200 described with reference to FIG. The description regarding the nozzle 200 may be referred to the nozzle unit 200E.

The nozzle portion 200E includes a nozzle piece 260, a flexible tube 270, and a connecting shaft 280. The flexible tube 270 extends vertically and penetrates the torque motor 400E. The nozzle piece 260 is attached to the lower end of the flexible tube 270. The high pressure working fluid is supplied to the flexible tube 270. The working fluid is guided by the flexible tube 270 and reaches the nozzle piece 260.

The nozzle piece 260 includes a lower surface 261 facing the upper surface 310 of the receiver 300. A discharge port 262 is formed on the lower surface 261. The taper angle of the tapered pipe portion extending toward the discharge port 262 is determined based on the design principle described in connection with the third embodiment. The high-pressure working fluid supplied to the nozzle piece 260 is discharged from the discharge port 262. After that, the working fluid flows into the receiver 300.

The connecting shaft 280 connects the flexible tube 270 to the intermediate portion of the magnetic rod 430. The flexible tube 270 and the nozzle piece 260 can reciprocate left and right according to the rotation of the magnetic rod 430 in the clockwise and counterclockwise directions.

When the magnetic rod 430 rotates clockwise around the connecting shaft 280, the discharge port 262 of the nozzle piece 260 is left along the straight line connecting the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312. Move to. Since the taper angle of the inner wall portion of the nozzle piece 260 is determined based on the design principle described in connection with the third embodiment, the rightward force exerted by the working fluid on the inner wall of the nozzle piece 260 is small. Therefore, the nozzle piece 260 can move quickly to the left. When the nozzle piece 260 moves to the left, the overlapping area between the discharge port 262 and the left inflow port 311 increases, while the overlapping area between the discharge port 262 and the right inflow port 312 decreases. In this case, the inflow rate of the working fluid into the left flow path 313 formed in the receiver 300 exceeds the flow rate of the working fluid flowing into the right flow path 314.

When the magnetic rod 430 rotates counterclockwise around the connecting shaft 280, the discharge port 262 of the nozzle piece 260 is on the right along the straight line connecting the center point LCP of the left inflow port 311 and the center point RCP of the right inflow port 312. Move towards. Since the taper angle of the inner wall portion of the nozzle piece 260 is determined based on the design principle described in connection with the third embodiment, the leftward force exerted by the working fluid on the inner wall of the nozzle piece 260 is small. Therefore, the nozzle piece 260 can move quickly to the right. When the nozzle piece 260 moves to the right, the overlapping area between the discharge port 262 and the right inflow port 312 increases, while the overlapping area between the discharge port 262 and the left inflow port 311 decreases. In this case, the inflow rate of the working fluid into the right flow path 314 formed in the receiver 300 exceeds the flow rate of the working fluid flowing into the left flow path 313.

The servo valve 100E includes a spool valve 700. The spool valve 700 includes a housing 710, a spool 720, and a cantilever spring 730. The spool 720 is arranged in the housing 710. As a result, a flow path through which the working fluid flows is formed in the housing 710. The cantilever spring 730 connects the housing 710 and the spool 720. The cantilever spring 730 applies a force to the spool 720 to keep the spool 720 in the closed position. When the spool 720 is in the closed position, the spool valve 700 cuts off the supply path of the working fluid from the pumps 510, 520 to the actuator 600. When the spool 720 moves from the closed position to the left or right, the spool valve 700 opens the supply path of the working fluid from the pumps 510 and 520 to the actuator 600.

Seven ports 711 to 717 are formed in the housing 710. The port 711 is connected to the left outlet 315 of the receiver 300 so that fluid can flow. The port 712 is connected to the right outlet 316 of the receiver 300 so that fluid can flow. Pumps 510 and 520 are attached to ports 713 and 714, respectively. The ports 715 and 716 are connected to the actuator 600 so that fluid can flow. The tank 530 is attached to the port 717.

The spool 720 includes four bulkheads 721,722,723,724 and a connecting shaft 725 connecting these bulkheads 721,722,723,724. The connecting shaft 725 extends substantially horizontally. The partition wall 721 is formed at the left end of the connecting shaft 725. The partition wall 722 is formed at the right end of the connecting shaft 725. The partition wall 723 is located between the partition walls 721 and 722. The partition wall 724 is located between the partition walls 722 and 723.

The partition walls 721,722,723,724 divide the internal space of the housing 710 into five chambers 741,742,743,744,745. Chamber 741 is formed on the far left. Chamber 742 is formed on the far right. The chamber 743 is formed between the partition walls 721 and 723. The chamber 744 is formed between the partition walls 722 and 724. The chamber 745 is formed between the partition walls 723 and 724.

When the nozzle piece 260 moves to the left, the working fluid mainly flows from the discharge port 262 of the nozzle piece 260 into the left inflow port 311 of the receiver 300. The working fluid that has flowed into the left inflow port 311 then flows into the chamber 741 through the left flow path 313 of the receiver 300, the left outflow port 315 of the receiver 300, and the port 711 of the spool valve 700. As a result, the internal pressure of the chamber 741 increases and the spool 720 moves to the right from the closed position. During this time, the working fluid existing in the chamber 742 is ejected from the right inflow port 312 through the port 712 of the spool valve 700, the right outflow port 316 of the receiver 300, and the right flow path 314 of the receiver 300. After that, when the nozzle piece 260 returns to the neutral position, the working fluid discharged from the discharge port 262 of the nozzle piece 260 flows into the left inflow port 311 and the right inflow port 312 of the receiver 300 substantially evenly. During this time, the force acting on the spool 720 to the left is larger than the force acting on the spool 720 to the right by the restoring force of the cantilever spring 730. Therefore, the spool 720 moves to the left and returns to the closed position.

When the nozzle piece 260 moves to the right, the working fluid mainly flows from the discharge port 262 of the nozzle piece 260 into the right inflow port 312 of the receiver 300. The working fluid that has flowed into the right inflow port 312 then flows into the chamber 742 through the right flow path 314 of the receiver 300, the right outflow port 316 of the receiver 300, and the port 712 of the spool valve 700. As a result, the internal pressure of the chamber 742 increases and the spool 720 moves to the left from the closed position. During this time, the working fluid existing in the chamber 741 is ejected from the left inflow port 311 through the port 711 of the spool valve 700, the left outflow port 315 of the receiver 300, and the left flow path 313 of the receiver 300. After that, when the nozzle piece 260 returns to the neutral position, the working fluid discharged from the discharge port 262 of the nozzle piece 260 flows into the left inflow port 311 and the right inflow port 312 of the receiver 300 substantially evenly. During this time, the force acting on the spool 720 to the right is larger than the force acting on the spool 720 to the left by the restoring force of the cantilever spring 730. Therefore, the spool 720 moves to the right and returns to the closed position.

The bulkhead 723 closes the port 715 when the spool 720 is in the closed position. At this time, the partition wall 724 closes the port 716. Pump 510 supplies high pressure hydraulic fluid to chamber 743 through port 713. Pump 520 supplies high pressure hydraulic fluid to chamber 744 through port 714. When the spool 720 moves to the right from the closed position, the supply path of the working fluid from the chamber 743 to the actuator 600 and the discharge path of the working fluid from the actuator 600 to the chamber 745 are opened. When the spool 720 moves to the left from the closed position, the supply path of the working fluid from the chamber 744 to the actuator 600 and the discharge path of the working fluid from the actuator 600 to the chamber 745 are opened. Therefore, the outflow amount of the working fluid from the ports 715 and 716 to the actuator 600 is adjusted by the left-right movement of the nozzle piece 260. In this embodiment, the first outlet is exemplified by one of ports 715 and 716. The second outlet is exemplified by the other of ports 715 and 716.

The actuator 600 includes a housing 610 and a movable piece 620. Two ports 611 and 612 are formed in the housing 610. The port 611 of the actuator 600 is connected to the port 715 of the spool valve 700 so that fluid can flow. The port 612 of the actuator 600 is connected to the port 716 of the spool valve 700 so that fluid can flow.

The movable piece 620 includes a partition wall 621 and a rod 622. The partition wall 621 divides the internal space of the housing 610 into a left chamber 631 and a right chamber 632. Port 611 connects to the left chamber 631. Port 612 connects to the right chamber 632. The rod 622 extends to the right from the partition wall 621 and projects out of the housing 610. The rod 622 is connected to another external device (not shown) located outside the housing 610. In this embodiment, the air chamber is exemplified by the internal space of the housing 610.

When the spool 720 moves to the right from the closed position, the working fluid supplied from the pump 510 to the chamber 743 through the port 713 flows into the left chamber 631 through the ports 715 and 611. As the internal pressure of the left chamber 631 increases, the movable piece 620 moves to the right. During this time, the right chamber 632 communicates with the chamber 745 via ports 612 and 716. The working fluid existing in the right chamber 632 is pushed out of the right chamber 632 by the movable piece 620 moving to the right and flows into the chamber 745. The working fluid flowing into the chamber 745 is then stored in the tank 530.

When the spool 720 moves to the left from the closed position, the working fluid supplied from the pump 520 to the chamber 744 through the port 714 flows into the right chamber 632 through the ports 716 and 612. As the internal pressure of the right chamber 632 increases, the movable piece 620 moves to the left. During this time, the left chamber 631 communicates with the chamber 745 via ports 611 and 715. The working fluid existing in the left chamber 631 is pushed out of the left chamber 631 by the movable piece 620 moving to the left and flows into the chamber 745. The working fluid flowing into the chamber 745 is then stored in the tank 530.

In FIG. 8, the receiver 300 is drawn separately from the housing 710 of the spool valve 700. However, the receiver 300 may be integrally formed with the housing 710 of the spool valve 700.

In this embodiment, the cantilever spring 730 is connected to the spool 720 and the housing 710. Instead of the cantilever spring 730, an elastic member connecting the spool 720 and the nozzle portion 200E may be used.

In this embodiment, the actuator 600 is connected to the spool valve 700. However, the actuator 600 may be directly connected to the receiver 300.

<8th Embodiment>
The present inventors analyzed the relationship between the taper angle and the pressure distribution in the nozzle using a plurality of models having different taper angles. In the eighth embodiment, the analysis result will be described.

9A to 9C are contour diagrams showing the pressure distribution of the working fluid around the discharge port. The relationship between the taper angle and the pressure distribution in the nozzle will be described with reference to FIGS. 9A-9C.

FIG. 9A shows the nozzle 201 and the receiver 301. A nozzle flow path 202 is formed in the nozzle 201. The receiver 301 is formed with a left flow path 302 and a right flow path 303. A gap 203 is formed between the lower surface of the nozzle 201 and the upper surface of the receiver 301. The taper angle β of the nozzle 201 is “0 °”. Nozzle 201 is moving to the right from the neutral position.

FIG. 9A shows a plurality of contour lines representing the pressure distribution in the nozzle flow path 202, the gap 203, the left flow path 302, and the right flow path 303. As shown in FIG. 9A, the region representing the highest pressure Pmax in the pressure distribution is represented at the top of the nozzle flow path 202. The region representing the highest pressure Pmin in the pressure distribution appears on the left side of the gap 203.

One contour line extends vertically in the region of the nozzle flow path 202 near the discharge port. The region on the left side of the contour line is the region of pressure P1. The region on the right side of the contour line is the region of pressure P2, which is smaller than pressure P1. The region above the region of pressure P1 is the region of pressure P3 that is greater than pressure P1. The region of pressure P3 is separated from the region of pressure P1 by a horizontally extending contour line. As shown in FIG. 9A, the left portion of the inner wall forming the nozzle flow path 202 is exposed to the high pressure P1, while the right portion of the inner wall forming the nozzle flow path 202 is exposed to the low pressure P2. Will be done. Therefore, the nozzle 201 receives a force acting to the left from the working fluid. Since the force received by the nozzle 201 from the working fluid is in the direction opposite to the moving direction of the nozzle 201 (that is, to the right), the responsiveness of the nozzle 201 is poor.

Similar to FIG. 9A, FIG. 9B shows the receiver 301. FIG. 9B further shows the nozzle 204. A nozzle flow path 205 is formed in the nozzle 204. A gap 206 is formed between the lower surface of the nozzle 204 and the upper surface of the receiver 301. The taper angle β of the nozzle 204 is “β1 (> 0 °)”. The relative position of the nozzle 204 with respect to the receiver 301 is the same as that of the nozzle 201.

The pressures Pmax and Pmin appear at substantially the same positions as in FIG. 9A. A substantially horizontal contour line representing the boundary between the pressures P1 and P3 approaches the discharge port. This means that the difference between the pressure at the left portion of the nozzle flow path 205 and the pressure at the right portion of the nozzle flow path 205 is smaller than the left-right balance of the pressure in the nozzle flow path 202. Therefore, the nozzle 204 has a higher responsiveness than the nozzle 201. However, since the left portion of the inner wall forming the nozzle flow path 205 is exposed to a higher pressure than the right portion of the inner wall forming the nozzle flow path 205, the displacement of the nozzle 204 to the right is due to the displacement of the working fluid. Slightly inhibited by pressure.

Similar to FIG. 9A, FIG. 9C shows the receiver 301. FIG. 9B further shows the nozzle 207. A nozzle flow path 208 is formed in the nozzle 207. A gap 209 is formed between the lower surface of the nozzle 207 and the upper surface of the receiver 301. The taper angle β of the nozzle 207 is “β2 (> β1)”. The relative position of the nozzle 207 with respect to the receiver 301 is the same as that of the nozzle 201.

The pressures Pmax and Pmin appear at substantially the same positions as in FIG. 9A. The contour lines representing the boundary between the pressures P1 and P3 are closer to horizontal than the contour lines of FIG. 9B. Therefore, the nozzle 207 has a higher responsiveness than the nozzle 204. Since the pressure exposed to the left portion of the inner wall forming the nozzle flow path 205 is approximately equal to the pressure exposed to the right portion of the inner wall forming the nozzle flow path 205, the pressure of the working fluid is to the right of the nozzle 204. Almost no inhibition of displacement to.

FIG. 10A is a graph showing the relationship between the relative position of the nozzle 201 with respect to the receiver 301, the flow rate of the working fluid discharged from the nozzle 201, and the force received by the nozzle 201 from the working fluid. FIG. 10B is a graph showing the relationship between the relative position of the nozzle 204 with respect to the receiver 301, the flow rate of the working fluid discharged from the nozzle 204, and the force received by the nozzle 204 from the working fluid. FIG. 10C is a graph showing the relationship between the relative position of the nozzle 207 with respect to the receiver 301, the flow rate of the working fluid discharged from the nozzle 207, and the force received by the nozzle 207 from the working fluid. The relationship between the taper angle β and the pressure in the nozzles 201, 204, 207 will be described with reference to FIGS. 3A, 3B, 9-10C.

The horizontal axes of the graphs of FIGS. 10A, 10B and 10C represent the relative positions of the nozzles 201, 204 and 207 with respect to the receiver 301, respectively. The origin of each of the graphs of FIGS. 10A, 10B and 10C represents a neutral position. The vertical axis of the graphs of FIGS. 10A, 10B and 10C is the discharge amount of the working fluid, the force received by the inner walls of the nozzles 201, 204, 207 from the working fluid, and the lower surface of the nozzles 201, 204, 207 (that is, the receiver). The surface facing 301) indicates the force received from the working fluid, the force received by the outer peripheral surfaces of the nozzles 201, 204, 207 from the working fluid, and the sum of these forces.

From the graphs of FIGS. 10A, 10B and 10C, it can be seen that when the taper angle β approaches 0 °, the force received by the inner wall of the nozzle from the working fluid occupies a large part of the total force received by the nozzle from the working fluid. .. As the taper angle β deviates from 0 °, the influence of the force on the inner wall of the nozzle from the working fluid becomes smaller. The analysis results shown in FIGS. 9 to 10C are in agreement with the dynamic model (see FIGS. 3A and 3B) described in connection with the second embodiment, and the effect of the taper angle β on the response performance of the nozzle is effective. Demonstrate sex. The designer who designs the nozzle may determine the taper angle β in consideration of the horizontal pressure exerted by the working fluid on the inner wall of the nozzle and the resistance at the discharge port of the nozzle. Therefore, the principle of the above-described embodiment is not limited to a specific value of the taper angle β.

The embodiments of the present invention have been described above. In the present embodiment, the taper angle β determined by the tapered inner wall connected to the discharge port of the nozzle is made larger than twice the angle α formed by the extending direction of the flow path and the direction orthogonal to the inflow surface. As a result, the component force of the flow force (force that hinders the displacement of the nozzle) received by the tapered inner wall from the fluid is reduced, and the nozzle can be quickly displaced, so that the response speed of the actuator is improved.

The flow force received by the nozzle increases in proportion to the pressure gradient represented by the above equation (2). As shown in FIG. 11, consider a case where the nozzle NZL moves in the direction of arrow D toward the left flow path LFP. At the bottom of FIG. 11, a graph of the pressure gradient of the working fluid in the vicinity of the discharge port is illustrated. As shown by the alternate long and short dash line in the graph of FIG. 11, when the pressure of the working fluid rises from the left flow path LFP side to the right flow path RFP side near the discharge port and the pressure gradient rises to the right, arrow D is indicated. Generates a flow force that acts in the opposite direction. As a result, the movement of the nozzle NZL is hindered. On the other hand, as shown by the solid line in the graph of FIG. 11, if the pressure of the working fluid can be kept constant or the pressure gradient can be lowered to the left, the flow force that hinders the movement of the nozzle NZL can be suppressed.

作動流体の流線の半径ｒは、ノズルＮＺＬの対向面とレシーバＲＣＶの流入面との間隔Ｌｎｇを用いて、以下の式（４）で表される。

下式（５）に示すように、フローフォースＦＦは、作動流体の流線の半径ｒに反比例するので、下式（６）が成り立つ。また、式（６）から式（７）が導かれる。

Here, as shown by the following equation (3), it is assumed that the flow force FF acting in the direction opposite to the moving direction of the nozzle NZL is proportional to the pressure gradient shown in the above equation (2).

The radius r of the streamline of the working fluid is expressed by the following equation (4) using the distance Lng between the facing surface of the nozzle NZL and the inflow surface of the receiver RCV.

As shown in the following equation (5), since the flow force FF is inversely proportional to the radius r of the streamline of the working fluid, the following equation (6) holds. Further, the equation (7) is derived from the equation (6).

FIG. 12 is a diagram illustrating the relationship between the pressure gradient obtained from the above relational expression and the angle ratio β / α. FIG. 12 shows the pressure gradient of the working fluid from the left flow path LFP side to the right flow path RFP side when the nozzle NZL moves to the left flow path LFP side, and the inclination angle α of the flow path is 30 degrees. The cases of 40 degrees, 50 degrees, and 60 degrees are shown. When the pressure gradient is larger than 0, the flow force FF increases. Further, when the pressure gradient is zero or less, the flow force FF is reduced. From the relationship shown in FIG. 12, if the angle ratio β / α is made larger than 2, that is, if the taper angle β of the nozzle is made larger than twice the inclination angle α of the flow path, the pressure gradient becomes zero or less. Can be suppressed. With such a configuration, the flow force can be suppressed, so that the nozzle can be easily moved and the response speed of the actuator is improved.

The principles of the above embodiments are described on the basis of a symmetrical structure with respect to the vertical line drawn on the nozzle in the neutral position. However, the servo valve may have a structure that is asymmetric with respect to the vertical line. For example, the inclination angle of the left flow path with respect to the vertical line may be different from the inclination angle of the right flow path with respect to the vertical line.

The design principles described in connection with the various embodiments described above are applicable to various servo valves and fluid systems. Even if some of the various features described in connection with one of the various embodiments described above apply to servo valves and fluid systems described in connection with another embodiment described above. good.

The outline of one aspect of the present invention is as follows. The one-phase servo valve of the present invention uses a fluid to drive an actuator. The servo valve has a nozzle including a discharge edge forming the contour of the discharge port from which the fluid is discharged, a tapered inner wall narrowing toward the discharge edge, and the fluid discharged from the discharge port. A receiver having a flow path formed therein is provided. The nozzle is displaced in a second direction different from the discharge direction in which the fluid is discharged. The extending direction of the flow path is inclined at an angle α with respect to the direction orthogonal to the inflow surface facing the nozzle. The taper angle defined by the tapered inner wall is larger than twice the angle α.

According to the above configuration, the taper angle determined by the tapered inner wall is larger than twice the angle α, so that the component force of the flow force that the tapered inner wall receives from the fluid in the displacement direction of the nozzle becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the flow path may include a first flow path and a second flow path arranged in the displacement direction of the nozzle. The extension direction may be different between the first flow path and the second flow path. The taper angle may be larger than the angle between the first flow path and the second flow path.

According to the above configuration, since the taper angle is larger than the angle between the first flow path and the second flow path, the component force of the flow force received from the fluid by the tapered inner wall in the displacement direction of the nozzle is small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the servo valve is in the direction along the alignment line in which the first inflow port formed as the end of the first flow path and the second inflow port formed as the end of the second flow path are aligned. , A drive unit for driving the nozzle may be further provided. The drive unit is displaced on the alignment line from a neutral position where an extension line extending from the center of the discharge port in the discharge direction of the fluid intersects the alignment line between the first inlet and the second inlet. The nozzle may be driven so as to do so.

According to the above configuration, since the taper angle is larger than the angle between the first flow path and the second flow path, the component force of the flow force received from the fluid by the tapered inner wall in the direction along the alignment line becomes small. .. Since the nozzle can be quickly displaced on the alignment line with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the virtual plane including the extension line and the alignment line and the tapered inner wall may form a straight first line of intersection and a straight second line of intersection. When the nozzle is in the neutral position, the extension line of the first line of intersection may extend into the first inlet, and the extension line of the second line of intersection may extend into the second inlet. ..

According to the above configuration, the extension line of the first line of intersection extends into the first inflow port, and the extension line of the second line of intersection extends into the second inflow port, so that the taper angle of the tapered inner wall becomes large. .. Therefore, the component force of the flow force received from the fluid by the tapered inner wall in the direction along the alignment line becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the taper angle may be an intersection angle defined by the first line of intersection and the second line of intersection.

According to the above configuration, the extension line of the first line of intersection extends into the first inflow port, and the extension line of the second line of intersection extends into the second inflow port, so that the first line of intersection and the second line of intersection extend. The taper angle defined as the line of intersection defined by and increases. Therefore, the component force of the flow force received from the fluid by the tapered inner wall in the direction along the alignment line becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, when the drive unit brings the extension line closer to the center of the first inflow port from the neutral position, the flow force brought from the fluid is on the first intersection line rather than on the second intersection line. You may be stronger. When the drive unit brings the extension line closer to the center of the second inflow port from the neutral position, the flow force may be stronger on the second intersection than on the first intersection.

According to the above configuration, when the drive unit brings the extension line closer to the center of the first inflow port from the neutral position, the flow force provided by the fluid becomes stronger on the first intersection line than on the second intersection line. .. However, since the taper angle of the tapered inner wall is large, the component force of the flow force in the direction along the alignment line becomes small. When the drive unit brings the discharge direction closer to the center of the second inflow port, the flow force becomes stronger on the second intersection than on the first intersection. However, since the taper angle of the tapered inner wall is large, the component force of the flow force in the direction along the alignment line becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the virtual plane including the extension line and the alignment line and the tapered inner wall may form a first line of intersection and a second line of intersection. The tapered inner wall may be a curved surface formed so that the first line of intersection and the second line of intersection are curved. When the nozzle is in the neutral position, the tangent at the midpoint of the first line of intersection extends into the first inflow port, and the tangent at the midpoint of the second line of intersection is in the second inflow port. It may be extended.

According to the above configuration, the tangent line at the midpoint of the first line of intersection extends into the first inflow port, and the tangent line at the midpoint of the second line of intersection extends into the second inflow port. Properly guided to the 1st and / or 2nd inlets. In addition, since the taper angle of the tapered inner wall becomes large, the component force of the flow force received from the fluid by the tapered inner wall in the direction along the alignment line becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the taper angle may be the intersection angle of the two tangents.

According to the above configuration, the extension of the first line of intersection extends into the first inflow port, and the extension of the second line of intersection extends into the second inflow port, so it is defined as the intersection angle of the two tangents. The taper angle increases. Therefore, the component force of the flow force received from the fluid by the tapered inner wall in the direction along the alignment line becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

The servo valve according to another aspect of the present invention is a servo valve that drives an actuator using a fluid, and narrows toward the discharge edge forming the contour of the discharge port from which the fluid is discharged and the discharge edge. A nozzle including a tapered inner wall, a first inflow port into which a part of the fluid discharged from the discharge port flows in, and a second inflow port into which another part of the fluid discharged from the discharge port flows in. A receiver including an inflow surface in which the nozzle is formed, and a drive unit for driving the nozzle along an alignment line in which the first inflow port and the second inflow port are aligned are provided. The drive unit is displaced on the alignment line from a neutral position where an extension line extending from the center of the discharge port in the discharge direction of the fluid intersects the alignment line between the first inlet and the second inlet. The nozzle is driven so as to do so. The virtual plane that includes the extension line and the alignment line and the tapered inner wall form a straight first line of intersection and a straight second line of intersection. When the nozzle is in the neutral position, the extension line of the first line of intersection extends into the first inlet, and the extension line of the second line of intersection extends into the second inlet.

According to the above configuration, when the nozzle is in the neutral position, the extension line of the first line of intersection extends into the first inlet, and the extension line of the second line of intersection extends into the second inlet, so that it is tapered. The taper angle of the inner wall becomes large. Therefore, the component force of the flow force received from the fluid by the tapered inner wall in the direction along the alignment line becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the taper angle may be 90 ° or more.

According to the above configuration, since the taper angle is 90 ° or more, the component force of the flow force that the tapered inner wall receives from the fluid in the displacement direction of the nozzle becomes small. Since the nozzle can be quickly displaced with little influence from the fluid, the servo valve can operate at a high response speed and drive the actuator quickly.

In the above configuration, the servo valve may further include a housing in which a flow path through which the fluid flows is formed. A first outlet and a second outlet may be formed in the housing. The drive unit may displace the nozzle along the alignment line to adjust the amount of the fluid flowing out from the first outlet and the amount of the fluid flowing out from the second outlet.

According to the above configuration, the drive unit displaces the nozzle along the alignment line to adjust the amount of fluid flowing out from the first outlet and the amount of fluid flowing out from the second outlet, so that the designer Can operate the actuator connected to the servo valve by utilizing the fluctuation of the ratio of the outflow amount from the first outlet and the second outlet.

The fluid system according to still another aspect of the present invention includes the above-mentioned servo valve and a movable piece displaced by the fluid in an air chamber communicating with the first outlet and the second outlet.

According to the above configuration, since the fluid device has the above-mentioned servo valve, it can operate at a high response speed.

The principle of the above-described embodiment is suitably used for various devices that obtain a driving force from a fluid.

100, 100A-100E ... Servo valve 200, 200B, 200C, 200D ... Nozzle 200E ... Nozzle part (nozzle)
221 ... Discharge port 222 ... Discharge edges 240, 240B, 240C ...・ ・ Tapered inner wall 262 ・ ・ ・ ・ ・ ・ Discharge port 300 ・ ・ ・ ・ ・ ・ Receiver 310 ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Top surface (inflow surface)
311 ... Left inflow port (1st inflow port or 2nd inflow port)
312 ... Right inlet (2nd inlet or 1st inlet)
313 ... Left flow path (first flow path or second flow path)
314 ... Right flow path (second flow path or first flow path)
400 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・·····································································································································・ ・ ・ ・ ・ Housing 715 ・ ・ ・ ・ ・ Port (1st outlet or 2nd outlet)
716 ... Port (2nd outlet or 1st outlet)
LCP ・ ・ ・ ・ ・ ・ Center point (center of 1st inflow port or 2nd inflow port)
LEX ・ ・ ・ ・ ・ ・ Extension line (extension line of the first line or the second line of intersection)
LIC, LIS ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・
LTG ... Tangent (tangent to the first or second line of intersection)
RCP ・ ・ ・ ・ ・ ・ Center point (center of 2nd inflow port or 1st inflow port)
REX ・ ・ ・ ・ ・ ・ Extension line (extension line of the second line or the first line of intersection)
RIC, RIS ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・
RTG ... Tangent line (tangent line of 2nd line or 1st line of intersection)
VL ... Vertical line (extension line extending in the first direction)

Claims (14)

A servo valve that uses fluid to drive an actuator.
A nozzle that includes a discharge edge that forms the contour of the discharge port from which the fluid is discharged, and a tapered inner wall that narrows toward the discharge edge.
A receiver having a flow path through which the fluid discharged from the discharge port flows is provided.
The nozzle is displaced in a direction different from the discharge direction in which the fluid is discharged.
The extension direction of the flow path is inclined at an angle α with respect to the direction orthogonal to the inflow surface facing the nozzle.
A servo valve whose taper angle determined by the tapered inner wall is larger than twice the angle α. The flow path includes a first flow path and a second flow path arranged in the displacement direction of the nozzle.
The extension direction is different between the first flow path and the second flow path.
The servo valve according to claim 1, wherein the taper angle is larger than the clearance angle between the first flow path and the second flow path. A drive unit that drives the nozzle in a direction along an alignment line in which a first inflow port formed as an end portion of the first flow path and a second inflow port formed as an end portion of the second flow path are aligned. With more
The drive unit is arranged so that an extension line extending from the center of the discharge port in the discharge direction of the fluid is displaced on the alignment line from a neutral position intermediate between the first inflow port and the second inflow port. The servo valve according to claim 2, which drives a nozzle. The virtual plane that includes the extension line and the alignment line and the tapered inner wall form a straight first line of intersection and a straight second line of intersection.
3. When the nozzle is in the neutral position, the extension line of the first line of intersection extends into the first inlet, and the extension line of the second line of intersection extends into the second inlet. Servo valve described in. The servo valve according to claim 4, wherein the taper angle is an intersection angle defined by the first line of intersection and the second line of intersection. When the drive unit brings the extension line closer to the center of the first inflow port from the neutral position, the flow force provided by the fluid becomes stronger on the first intersection line than on the second intersection line.
According to claim 4 or 5, when the drive unit brings the extension line closer to the center of the second inflow port from the neutral position, the flow force becomes stronger on the second intersection line than on the first intersection line. Described servo valve. The virtual plane that includes the extension line and the alignment line and the tapered inner wall form the first line of intersection and the second line of intersection.
The tapered inner wall is a curved surface formed so that the first line of intersection and the second line of intersection are curved.
When the nozzle is in the neutral position, the tangent at the midpoint of the first line of intersection extends into the first inflow port, and the tangent at the midpoint of the second line of intersection is in the second inflow port. The servo valve according to claim 3 which extends. The servo valve according to claim 7, wherein the taper angle is an intersection angle of the two tangents. A servo valve that uses fluid to drive an actuator.
A nozzle that includes a discharge edge that forms the contour of the discharge port from which the fluid is discharged, and a tapered inner wall that narrows toward the discharge edge.
A receiver including an inflow surface formed with a first inflow port into which a part of the fluid discharged from the discharge port flows in and a second inflow port into which another part of the fluid discharged from the discharge port flows. When,
A drive unit for driving the nozzle is provided along an alignment line in which the first inlet and the second inlet are aligned.
The drive unit is displaced on the alignment line from a neutral position where an extension line extending from the center of the discharge port in the discharge direction of the fluid intersects the alignment line between the first inlet and the second inlet. Drive the nozzle so that
Virtual plane and the tapered inner wall subsumes and the alignment line and the extension forms a first intersection line及beauty second intersection line,
The tapered inner wall is a curved surface formed so that the first line of intersection and the second line of intersection are curved.
When the nozzle is in the neutral position, the extension line of the first line of intersection extends into the first inlet, and the extension line of the second line of intersection extends into the second inlet. The servo valve according to any one of claims 1 to 8, wherein the taper angle is 90 ° or more. Further provided with a housing in which a flow path through which the fluid flows is formed.
A first outlet and a second outlet are formed in the housing.
The driving unit displaces the nozzle along the alignment line to adjust the outflow amount of the fluid from the first outlet and the outflow amount of the fluid from the second outlet. The servo valve according to any one of 9. The servo valve according to claim 11 and
A fluid device including a movable piece displaced by the fluid in an air chamber communicating with the first outlet and the second outlet. A servo valve that changes the flow of the fluid by displacing the relative position between the discharge port of the nozzle and the inflow port of the receiver into which the fluid discharged from the discharge port flows.
The nozzle includes a tapered inner wall that narrows towards the outlet.
The extending direction of the flow path continuing from the inflow port in the receiver is inclined at an angle α with respect to the direction orthogonal to the inflow surface of the receiver facing the nozzle.
The relative positions of the nozzle and the receiver are displaced in a direction different from the direction in which the discharge port discharges the fluid.
A servo valve whose taper angle determined by the tapered inner wall is larger than twice the angle α. A servo valve that changes the flow of the fluid by displacing the relative position between the discharge port of the nozzle and the inflow port of the receiver into which the fluid discharged from the discharge port flows.
The nozzle includes a tapered inner wall that narrows towards the outlet.
The inflow port has first and second inflow ports into which a part of the fluid flows, respectively.
As for the discharge direction of the fluid from the discharge port, an extension line extending from the center of the discharge port in the discharge direction is between the first inflow port and the second inflow port, and the first inflow port and the first inflow port. 2 Displace on the alignment line from the neutral position where the inflow port intersects the alignment line,
The first line of intersection and the second line of intersection are formed at the intersection of the virtual plane surrounding the extension line and the alignment line with the tapered inner wall.
The tapered inner wall is a curved surface formed so that the first line of intersection and the second line of intersection are curved.
A servo valve in which the extension line of the first line of intersection extends into the first inlet, and the extension line of the second line of intersection extends into the second inlet.

Images