Pre-tensioning-pre-twisting full-bridge 2D electro-hydraulic proportional directional valve

Abstract

A pre-tensioning-pre-twisting full-bridge 2D electro-hydraulic proportional directional valve can include a 2D valve, linear electro-mechanical converters at two ends of the 2D valve, and a compression-torsion coupling between the linear electro-mechanical converters. The 2D valve can include a valve core and a valve body, wherein the valve core is rotatably and axially slidably disposed inside an inner hole that is set along the axis line of the valve body. Each end shoulder of the valve core is provided with a pair of high pressure holes and low pressure holes, which are respectively communicated with a P opening and a T opening through an inner hole of the valve core.

Claims

1. A pre-tensioning-pre-twisting full-bridge electro-hydraulic proportional directional valve, comprising a valve consisting of a valve core and a valve body, wherein the valve core is rotatably and axially slidably disposed inside an inner hole that is set along an axis line of the valve body, each of a left end and a right end of the valve core is provided with an end shoulder; the inner hole of the valve body between the end shoulders is successively provided with a first opening, a second opening, a third opening, a fourth opening, and a fifth opening; the third opening is a liquid inlet, a pressure of which is a system pressure; the valve core between the end shoulders is provided with two middle shoulders that are respectively positioned at the second opening and the fourth opening; and each of the shoulders is slidably in a seal fit with the inner hole of the valve body; wherein: two ends of the valve are respectively connected with linear electro-mechanical converters by means of a compression-torsion coupling and cylindrical compression springs; a left sensing cavity at the left end and a right sensing cavity at the right end are formed respectively among the end shoulders of the valve core, a plurality of end covers, and the valve body; each of the end shoulders of the valve core is provided with a pair of high pressure holes and low pressure holes, namely, a first high pressure hole (b), a first low pressure hole (d), a second high pressure hole (c), and a second low pressure hole (e); wherein the first high pressure hole (b) and the second high pressure hole (c) are respectively communicated with the third opening through an inner hole of the valve core; and the first low pressure hole (d) and the second low pressure hole (e) are respectively communicated with the first and fifth openings through a trench at an inner side of the end shoulders of the valve core; a wall of the inner hole of each of the two ends of the valve body is provided with a pair of axisymmetric sensing channels (f.sub.1 and f.sub.2, and g.sub.1 and g.sub.2), respectively communicated with the left sensing cavity and the right sensing cavity; both of the pairs of high pressure holes and low pressure holes are arranged at two sides of one of the sensing channels, are intersected with the respective sensing channel to form two channel openings, and are in series connection with the sensing channel to form hydraulic resistance half bridges; the pressure of the left and right sensing cavities is respectively controlled by the hydraulic resistance half bridges at two ends; the compression-torsion coupling consists of a sliding wedge, two rolling bearings fixed respectively on two ends of a hinge pin running through an end of the valve core, a linear bearing mounted on the sliding wedge, and a pin bolt for restricting the sliding wedge to rotate; the cylindrical spring is mounted between the valve body and the sliding wedge, and a pre-compression amount of the cylindrical spring is slightly greater than the stroke of the valve core; the sliding wedge is slidably sleeved, by means of the linear bearing, on the pin bolt of an axial line parallel to the valve core; the sliding wedge is provided with a first inclined plane and a second inclined plane respectively positioned at two sides of the axis line of the valve body; the first inclined plane and the second inclined plane are phase-inversion symmetric according to the axis line; the two rolling bearings respectively roll on the first inclined plane and the second inclined plane, so that the valve core twists while axially moving; the inclined planes of the sliding wedge at two ends mutually interwork so that a twist angle of the valve core has a definite corresponding relation with a position of the valve core along the axis line; and the valve includes two movements comprising a linear movement and a rotation movement based on the valve core being disposed rotatably and axially slidably inside the inner hole of the valve body.

2. The proportional directional valve according to claim 1, wherein, the inclined planes of the sliding wedges located at the same side of the axis line press, respectively from an entry surface and a retreat surface along a direction of rotation of the valve core, the bearings located at the same side of the axis line.

3. The proportional directional valve according to claim 2, wherein the number of the first high pressure hole (b) and the second high pressure hole (c) on the end shoulder of the valve core is two, which are mutually and axisymmetrically distributed; the number of the first low pressure hole (d) and the second low pressure hole (e) on the end shoulder of the valve core is two, which are mutually and axisymmetrically distributed; and the first high pressure hole (b) and the second high pressure hole (c) are through holes, and are respectively communicated with the third opening through the inner hole of the valve core.

4. The proportional directional valve according to claim 3, wherein the high pressure holes and the low pressure holes adopt a rectangular window.

5. The proportional directional valve according to claim 1, wherein the number of the first high pressure hole (b) and the second high pressure hole (c) on the end shoulder of the valve core is two, which are mutually and axisymmetrically distributed; the number of the first low pressure hole (d) and the second low pressure hole (e) on the end shoulder of the valve core is two, which are mutually and axisymmetrically distributed; and the first high pressure hole (b) and the second high pressure hole (c) are through holes, and are respectively communicated with the third opening through the inner hole of the valve core.

6. The proportional directional valve according to claim 5, wherein the high pressure holes and the low pressure holes adopt a rectangular window.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic structural diagram of the invention.

(2) FIG. 2 is a schematic assembly diagram of the valve core and the valve body of the invention.

(3) FIG. 3 is a schematic structural diagram of the valve core.

(4) FIG. 4 is a section view of an internal structure of the valve core.

(5) FIG. 5 is a section view of the valve body.

(6) FIG. 6 is a schematic lateral view of the valve body.

(7) FIG. 7 is a schematic assembly diagram of the valve core and the rolling bearings.

(8) FIG. 8 is a schematic structural diagram of a top cover.

(9) FIG. 9 is a schematic structural diagram of an outside surface of the sliding wedge.

(10) FIG. 10 is a schematic structural diagram of an inside surface of the sliding wedge.

(11) FIG. 11 is a schematic diagram of a hydraulic guidance and control full bridge.

(12) FIGS. 1214 are force analysis and motion process diagrams of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(13) The following will further describe the present invention by reference to the accompanying drawings.

(14) Referring to FIGS. 110, a pre-tensioning-pre-twisting full-bridge 2D electro-hydraulic proportional directional valve includes bolts 1, 3, 12, 30 and 33, linear electro-mechanical converters 2 and 16, end covers 4 and 19, linear bearings 5, 13, 31 and 32, cylindrical compression springs 21 and 23, O-shaped sealing rings 6, 11, 15 and 29, pin bolts 7, 10, 22 and 24, a valve body 8, a valve core 9, rolling bearings 14, 27, 36 and 38, top covers 17 and 28, hinge pins 18 and 26, sliding wedges 20 and 25, a set screw 34, a steel ball 35, and sleeves 37 and 39.

(15) The pre-tensioning-pre-twisting full-bridge 2D electro-hydraulic proportional directional valve consists of a 2D valve, linear electro-mechanical converters 2 and 16 at two ends of the 2D valve, and a compression-torsion coupling positioned between the linear electro-mechanical converters 2 and 16, etc.

(16) The pre-tensioning-pre-twisting full-bridge 2D electro-hydraulic proportional directional valve includes the 2D valve consisting of the valve core 9 and the valve body 8, where the valve core 9 is rotatably and axially slidably disposed inside an inner hole which is set along the axis line of the valve body 8, each of the left end and the right end of the valve core 9 is provided with an end shoulder; the inner hole of the valve body between the end shoulders is successively provided with a T opening, an A opening, a P opening, a B opening and a T opening; the p opening is a liquid inlet, a pressure of which is a system pressure; the valve core between the end shoulders is provided with two middle shoulders which are respectively positioned at the A opening and the B opening; and each of the shoulders is slidably in a seal fit with the inner hole of the valve body 8; wherein:

(17) two ends of the 2D valve are respectively connected with linear electro-mechanical converters 2 and 16 by means of a compression-torsion coupling and cylindrical compression springs 23 and 21;

(18) a left sensing cavity h at the left end and a right sensing cavity j at the right end are formed respectively among the end shoulders of the valve core, the end covers 4 and 19 and the valve body 8;

(19) as shown in FIG. 3 and FIG. 4, each of the end shoulders of the valve core is provided with a pair of high pressure hole and low pressure hole, namely, a first high pressure hole b, a first low pressure hole d, a second high pressure hole c, and a second low pressure hole e; where the first high pressure hole b and the second high pressure hole c are through holes and are respectively communicated with the P opening through a hole a and an inner hole k of the valve core; and the first low pressure hole d and the second low pressure hole e are respectively communicated with the T opening through a trench at an inner side of the end shoulders of the valve core; and

(20) the number of the first high pressure hole b and the second high pressure hole c on the end shoulder of the valve core is two, which are mutually and axisymmetrically distributed; the number of the first low pressure hole d and the second low pressure hole e on the end shoulder of the valve core is two, which are mutually and axisymmetrically distributed. As shown in FIG. 5 FIG. 6, a wall of the inner hole of each of two ends of the valve body is provided with a pair of axisymmetrical sensing channels (f.sub.1 and f.sub.2, and g.sub.1 and g.sub.2), respectively communicated with the left sensing cavity h and the right sensing cavity j; as shown in FIG. 11, the a pair of high pressure hole and low pressure hole is arranged at two sides of one of the sensing channels and is intersected with the respective sensing channel to form two channel openings, and is in series connection with the sensing channel to form hydraulic resistance half bridges; the pressure of the sensing cavities is respectively controlled by the hydraulic resistance half bridges at two ends;

(21) the compression-torsion coupling consists of the sliding wedge 20, two rolling bearings 14 and 38 fixed respectively on two ends of the hinge pin 18 running through an end of the valve core, the linear bearings 13 and 32 mounted in holes p and q of the sliding wedge, and the pin bolts 10 and 22 for restricting the sliding wedge to rotate; the cylindrical compression spring 21 is mounted between the valve body and the sliding wedge, and a pre-compression amount of the spring is slightly greater than a stroke of the valve core; the sliding wedge may be slidably sleeved, by means of the linear bearings, on the pin bolts of an axial line parallel to the valve core; and

(22) the sliding wedge is provided with a first inclined plane and a second inclined plane respectively positioned at two sides of the axis line of the valve body; the first inclined plane and the second inclined plane are phase-inversion symmetric according to the axis line; the two rolling bearings respectively roll on the first inclined plane and the second inclined plane, so that the valve core twists while axially moving; the inclined planes of the sliding wedge at two ends mutually interwork so that a twist angle of the valve core has a definite corresponding relation with a position, of the valve core, along the axis line.

(23) The inclined planes of the sliding wedge positioned at two ends of the same side of the axis line press, respectively from an entry surface and a retreat surface along a direction of rotation of the valve core, the bearing of the same side at two ends of the valve core.

(24) The compression-torsion coupling is a structure for implementation of converting a rectilinear motion of the linear electro-mechanical converters to a twisting motion of the valve core. In this process, a feature of a large pressure gain of a hydraulic guidance and control bridge circuit of the 2D valve (a micro rotation angle is enough to cause a larger change of pressure of the sensing cavities) may be taken full advantage of. By means of a reasonable design of the compression-torsion coupling, a twisting moment for driving the valve core to rotate is enlarged, so that an adverse impact of nonlinear factors, for example, a friction force between the valve core and a hole of the valve core, on proportional characteristic may be minimized.

(25) The O-shaped sealing rings 6 and 11 are used for sealing between the end covers and the valve body; the O-shaped sealing rings 15 and 29 are used for sealing between the end covers and linear electro-mechanical converters; a large cylindrical end n of the top covers 17 and 28 is in an interference fit connection with the inner holes in the center of the sliding wedges 20 and 25; force outputted by a push rod of the linear electro-mechanical converters is applied to a small cylindrical end m of the top covers, and is axially transferred to the sliding wedges. The linear bearings 5 and 31 and the linear bearings 13 and 32 are respectively symmetrically mounted in the upper hole p and the lower hole q of the sliding wedge, so as to reduce the friction force of the sliding wedge sliding on the pin bolts; the set screw 34 bears the steel ball 35 against one end surface of the inner hole k of the valve core to seal one end of the inner hole k of the valve core; one end of the sleeves 37 and 39 bears against the valve core, and the other end bears against an inner ring of the rolling bearings 36 and 38, to act as a support bearing.

(26) The high pressure hole and the low pressure hole are shaped like a circle. A rectangular window having a large-area gradient may be used if it is required that an axial motion of the valve core has quick response to a rotational motion.

(27) The linear electro-mechanical converters are wet-type high voltage resistant proportional electromagnets, or other wet-type high voltage resistant linear electro-mechanical converters may be selected and used.

(28) The working principle of this embodiment: As shown in FIG. 12, when the proportional electromagnets at two ends of the 2D electro-hydraulic proportional valve is not energized, outward thrust F.sub.S applied by the springs to the sliding wedges (a left end and a right end are respectively represented with l and r) is transferred, by means of two axisymmetrical inclined planes of the sliding wedges and a contact position of the two rolling bearings, to the valve core. Due to effect of the inclined planes, in addition to bearing an axial tension F.sub.S, the valve core also bears a tangential force F.sub.t, two tangential forces of two contact positions at the same end are equal in size, and opposite in direction, and constitute a force couple. The axial force and the force couple applied by the sliding wedges at two ends to the valve core are opposite in direction. Therefore, the valve core is in a pre-tensioning and pre-twisting state when it is in a balance position. When the proportional electromagnets at a certain end of the 2D electro-hydraulic proportional valve is energized, thrust F.sub.m applied to the sliding wedges not only makes the axial force of the valve core out of balance, but also makes the twisting moment applied to the valve core out of balance, so that the valve core rotates. For example, when the proportional electromagnet at the left end is energized, a rightward electromagnetic thrust F.sub.ml is generated, so that force applied by the sliding wedge at the left end to the valve core is reduced, both axial force and twisting moment applied to two ends of the valve core are out of balance, and the valve core is subjected to a rightward axial driving force and a counterclockwise twisting moment (seen from left to right). The axial driving force is equivalent to a driving force of a direct-acting proportional valve. In a working condition characterized by high pressure and large flow, an axial motion of the valve core may be unable to be directly driven due to existence of hydrodynamic force and friction force. However, by reasonably selecting a smaller angle of the inclined plane of the sliding wedge and a larger distribution diameter of the rolling bearing, a larger tangential force may be obtained, so that the friction force of the valve core may be overcome enough to drive the valve core to counterclockwise rotate. Meanwhile, due to axial constraint of pin bolts, the sliding wedges at two ends may slide rightwards by taking the pin bolts as a guidance axis and taking the linear bearings as a supporting. A compression amount of the right-end spring is reduced; while a compression amount of the left-end spring is increased, so as to generate an extra spring force to balance the thrust of the proportional electromagnet (see FIG. 13). In this process, because the valve core counterclockwise rotates, a pressure of the left sensing cavity of the valve rises, while a pressure of the right sensing cavity decreases, and the valve core moves rightwards. In the motion process, because the rolling bearings at two ends of the valve core are restrained by the inclined planes of the sliding wedges at two ends, the valve core also rotates back (clockwise rotates) when it is moving rightwards, the pressure of the sensing cavities at two ends of the valve core restores to a steady-state balance value, and the valve core reaches a new balance position corresponding to the size the thrust of the proportional electromagnet (see FIG. 14). It is particularly to be pointed out that, when the pressure of the P opening of the valve is zero (equal to the pressure of the T opening), it is unable to drive a shaft of the valve core to move by means of change of the pressure of the sensing cavities at two ends. However, because no oil and fluid flows in a valve chamber, the valve core is not subjected to a hydrodynamic force or a clamping force. Therefore, an axial thrust generated by the proportional electromagnet after it is energized may directly drive the valve core to move. Under this condition, the working principle of the 2D electro-hydraulic proportional valve is the same as that of the direct-acting proportional valve.

(29) The embodiments described above are intended for explaining the present invention, and are not intended to limit the present invention. Any modification or alteration made within the spirit of the present invention and the protection scope of claims shall fall within the protection scope of the present invention.