An eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve

Abstract

This invention relates to a two-dimensional electro-hydraulic servo valve driven directly by an eccentric shaft motor, comprising a spool valve assembly, a motor fixed to the top right side of the spool valve assembly, and a fork fixed to the right end of the valve core inside the spool valve assembly. The output shaft of the motor is an eccentric shaft, which is inserted into the valve body of the spool valve assembly, and the end of the eccentric shaft is embedded in a spherical bearing. The outer spherical surface of the spherical bearing is fitted into a groove on the upper part of the fork. This invention allows axial displacement caused by valve core rotation, preventing valve core jamming; it can generate a large valve core torque with a small torque input, exhibiting high response and long lifespan; the motor and linear displacement sensor are plug-in, facilitating installation.

Description

Technical Field

[0001] This invention relates to a two-dimensional electro-hydraulic servo valve, and more particularly to a two-dimensional electro-hydraulic servo valve driven by an eccentric shaft motor. Background Technology

[0002] In existing two-dimensional servo valves, the motor-driven valve spool has high torque, long response time, and low frequency. However, when the valve spool torque is amplified by eccentrically driving the shift fork with a motor, it often causes significant wear on the bearings, which can lead to valve spool jamming, preventing rotation, and resulting in a short lifespan. Therefore, a novel structure for an eccentrically driven two-dimensional servo valve is needed. Summary of the Invention

[0003] The purpose of this invention is to solve the problems in the prior art and propose an eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve that allows axial displacement caused by valve core rotation, thus avoiding valve core jamming; it can generate large valve core torque with small torque input, and has high response and long life; the motor and linear displacement sensor are plug-in, making installation convenient.

[0004] To achieve the above objectives, the technical solution of the present invention is: an eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve, comprising a spool valve assembly, a motor fixed to the top right side of the spool valve assembly, and a fork fixed to the right end of the valve core inside the spool valve assembly. The output shaft of the motor is an eccentric shaft, which is inserted into the valve body of the spool valve assembly, and the end of the eccentric shaft is embedded in a spherical bearing. The outer spherical surface of the spherical bearing is fitted into a groove on the upper part of the fork.

[0005] Furthermore, the upper part of the fork has an upward-opening C-shaped groove, and a spherical bearing is laterally connected within the C-shaped groove. Symmetrical spring grooves are provided on both sides of the upper part of the fork, and a spring positioning shaft is provided within each spring groove. A return spring is fitted within the gap between the outer circumference of the spring positioning shaft and the inner cavity of the spring groove. The lower part of the fork has a downward-opening arch-shaped groove, and the right end of the valve core is connected within the arch-shaped groove. A circular through hole is laterally provided on the lower part of the fork, and a bolt is fitted within the circular through hole.

[0006] Furthermore, the right end of the slide valve assembly is fixedly connected to the LVDT body, the LVDT body contains an LVDT core, and the LVDT core is inserted into the right end cover of the slide valve assembly, with the end of the LVDT core inserted into the right end of the valve core.

[0007] Furthermore, the spool valve assembly includes a valve body, a valve sleeve, a valve core, a left end cap, a left valve core plug, a concentric ring, a concentric ring baffle, a first reset magnet, a second reset magnet, and a right end cap. The left end cap is bolted to the left end of the valve body, and the right end cap is bolted to the right end. A valve sleeve is installed inside the valve body, and the valve sleeve is fitted onto the valve core. A left valve core plug is embedded inside the left end of the valve core. A concentric ring is installed between the outer circumference of the right part of the valve core and the inner cavity of the right part of the valve sleeve. A concentric ring baffle is bolted to the right end of the valve sleeve, and the right end face of the concentric ring contacts the left end face of the concentric ring baffle. A second reset magnet is installed inside the right end of the concentric ring baffle, and a first reset magnet is installed on the outer circumference of the right part of the valve core. The first reset magnet and the second reset magnet are magnetically coupled, and both the first reset magnet and the second reset magnet are circular ring-shaped magnets.

[0008] Furthermore, the top surface of the inner cavity on the left side of the valve body and the top surface of the valve sleeve on the left side are both provided with semi-circular grooves, and the valve sleeve is positioned in the valve body by a positioning key.

[0009] Furthermore, the valve body has a fork rod reset hole and a side hole on its right side. The fork rod reset hole contains a slotted flat-end set screw, a spring plug, and a reset spring. The two ends of the reset spring are respectively engaged with the fork rod and the spring plug. The slotted flat-end set screw is threaded into the fork rod reset hole, and the end of the slotted flat-end set screw contacts the front end face of the spring plug. The side hole contains a slotted flat-end set screw and a side hole plug. The slotted flat-end set screw is threaded into the side hole, and the end of the slotted flat-end set screw contacts the front end face of the side hole plug. The end of the side hole plug is flat, and the end of the spring plug has a circular groove that accommodates the reset spring.

[0010] Furthermore, the motor is equipped with an angular displacement sensor.

[0011] Furthermore, the center of the end of the eccentric shaft of the motor is offset by 1 mm from the center of the upper part of the eccentric shaft.

[0012] The beneficial effects of this invention are:

[0013] The eccentric shaft of the motor of the present invention is engaged with the fork rod through the outer spherical surface of the spherical bearing, which can cooperate with the axial displacement generated when the valve core rotates, thereby avoiding the valve core jamming; at the same time, the spherical engagement generates minimal rolling friction, resulting in a long structural life.

[0014] This invention forms a torque amplification structure through the cooperation of an eccentric shaft, spherical bearing, fork rod, and valve core. Combined with the rapid response of the motor, it possesses the advantages brought by the motor.

[0015] This invention is a plug-in type, which is easy to assemble; the angular displacement sensor is directly on the motor, which can be either wet or dry type. Attached Figure Description

[0016] Figure 1 This is a perspective view of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention;

[0017] Figure 2 This is a front cross-sectional view of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention;

[0018] Figure 3 This is a side cross-sectional view of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention;

[0019] Figure 4 This is a perspective view of some components of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention;

[0020] Figure 5 This is a perspective view of the valve sleeve of a portion of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention.

[0021] Figure 6 This is a front sectional view of the valve sleeve, a component of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention.

[0022] Figure 7 This is a front view of the motor of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention;

[0023] Figure 8 This is a perspective view of the spherical bearing of a portion of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention.

[0024] Figure 9 This is a perspective view of the fork of a portion of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention;

[0025] Figure 10 This is a front cross-sectional view of the fork of a component of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention.

[0026] In the diagram: 1-Slide valve assembly, 2-Motor, 3-Spherical bearing, 4-Fork rod, 5-LVDT core, 6-LVDT body, 11-Valve body, 1101-Fork rod reset hole, 1102-Side hole, 12-Valve sleeve, 13-Valve core, 14-Left end cover, 15-Left valve core plug, 16-Positioning key, 17-Concentric ring, 18-Concentric ring baffle, 19-First reset magnet, 110-Second reset magnet, 111-Right end cover, 112-Slotted flat end set screw, 113-Spring plug, 114-Reset spring, 115-Side hole plug, 21-Eccentric shaft, 41-Spring groove, 42-Spring positioning shaft, 43-Circular through hole. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] like Figures 1 to 10 As shown, the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention includes a slide valve assembly 1, a motor 2 fixed to the top right side of the slide valve assembly 1, a spherical bearing 3 fixed to the end of the output shaft of the motor 2, a fork 4 fixed to the right end of the valve core 13 inside the slide valve assembly 1, an LVDT body 6 fixed to the right end of the slide valve assembly 1, and an LVDT core 5 disposed inside the LVDT body 6.

[0029] The output shaft of motor 2 is an eccentric shaft 21. The eccentric shaft 21 is inserted into the valve body 11 of the slide valve assembly 1 and the end of the eccentric shaft 21 is embedded in the spherical bearing 3. The outer spherical surface of the spherical bearing 3 is fitted into the groove on the upper part of the fork 4. The lower end of the fork 4 is fixed to the right end of the valve core 13. The LVDT core 5 is inserted into the right end cover 111 of the slide valve assembly 1 and the end of the LVDT core 5 is inserted into the right end of the valve core 13.

[0030] Specifically, the spool valve assembly 1 includes a valve body 11, a valve sleeve 12, a valve core 13, a left end cap 14, a left valve core plug 15, a concentric ring 17, a concentric ring baffle 18, a first reset magnet 19, a second reset magnet 110, and a right end cap 111. The left end cap 14 is bolted to the left end of the valve body 11, and the right end cap 111 is bolted to the right end. The valve sleeve 12 is installed inside the valve body 11 and fits onto the valve core 13. The left end cap 15 is embedded inside the left end of the valve core 13. A concentric ring 17 is installed between the outer circumference of the right side and the inner cavity of the right side of the valve sleeve 12. A concentric ring baffle 18 is fixed to the right end of the valve sleeve 12 by bolts. The right end face of the concentric ring 17 is in contact with the left end face of the concentric ring baffle 18. A second reset magnet 110 is installed inside the right end of the concentric ring baffle 18. A first reset magnet 19 is installed on the outer circumference of the right side of the valve core 13. The first reset magnet 19 and the second reset magnet 110 are magnetically engaged. Both the first reset magnet 19 and the second reset magnet 110 are circular ring-shaped magnets.

[0031] Specifically, a semi-circular groove is provided on the top surface of the inner cavity on the left side of the valve body 11 and the top surface of the left side of the valve sleeve 12. The valve sleeve 12 is positioned inside the valve body 11 by a positioning key 16.

[0032] Specifically, the valve body 11 has a fork rod reset hole 1101 and a side hole 1102 longitudinally arranged on the right side. The fork rod reset hole 1101 is equipped with a slotted flat-end set screw 112, a spring plug 113 and a reset spring 114. The two ends of the reset spring 114 are respectively engaged with the fork rod 4 and the spring plug 113. The slotted flat-end set screw 112 is threaded into the fork rod reset hole 1101 and its end is in contact with the front end face of the spring plug 113. The side hole 1102 is equipped with a slotted flat-end set screw 112 and a side hole plug 115. The slotted flat-end set screw 112 is threaded into the side hole 1102 and its end is in contact with the front end face of the side hole plug 115. The end of the side hole plug 115 is flat, and the end of the spring plug 113 is provided with a circular groove that accommodates the reset spring 114.

[0033] Specifically, motor 2 is equipped with an angular displacement sensor.

[0034] Specifically, the output shaft of motor 2 is an eccentric shaft 21, the center of the end of eccentric shaft 21 is offset by 1mm from the center of the upper part of eccentric shaft 21, and a spherical bearing 3 is embedded on the outer circumferential surface of the end of eccentric shaft 21.

[0035] Specifically, the upper part of the fork 4 has an upward-opening U-shaped groove, and a spherical bearing 3 is laterally fitted inside the U-shaped groove of the upper part of the fork 4; spring grooves 41 are symmetrically arranged on the left and right sides of the upper part of the fork 4, and a spring positioning shaft 42 is provided inside the spring groove 41. A return spring 114 is fitted in the gap between the outer periphery of the spring positioning shaft 42 and the inner cavity of the spring groove 41; the lower part of the fork 4 has an downward-opening arch-shaped groove, and a valve core 13 is fitted inside the arch-shaped groove of the lower part of the fork 4; a circular through hole 43 is laterally provided on the lower part of the fork 4, and a bolt is fitted inside the circular through hole 43.

[0036] The working process of this invention:

[0037] The operation of the eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve of the present invention will be described in conjunction with the accompanying drawings.

[0038] When motor 2 moves, the eccentric shaft 21 of motor 2 drives the spherical bearing 3 to move, thereby driving the valve core 13 to rotate. During the rotation of valve core 13, axial movement is also generated. The working principle of slide valve assembly 1 is the same as that of the previously applied 2D servo valve. The main inventive point of this invention lies in the direct drive method of eccentric shaft motor and the cooperation between spherical bearing and fork.

[0039] The motor 2 engages with the fork 4 via the outer spherical surface of the spherical bearing 3. When the valve core 13 rotates, if it were not a deep groove spherical bearing as described in this invention, the valve core 13 would jam and become immobile due to both rotation and axial movement.

[0040] When the valve core 13 moves axially by ±1mm, the spherical bearing 3 will rotate, resulting in very little friction. Compared to existing sliding friction, the friction between the outer spherical surface of the spherical bearing 3 and the fork 4 in this application is rolling friction, leading to a longer lifespan, reaching the billion-cycle level. Only by reducing the coefficient of friction can a long lifespan be achieved. With existing sliding friction, the bearing will quickly wear down, and continued rotation will result in idle travel and a "clicking" sound.

[0041] The eccentricity of the eccentric shaft 21 in this invention can be made very small. The eccentricity of the motor 2 can be 1mm, and the distance from the contact point between the spherical bearing 3 and the fork 4 to the valve core 13 can be 20mm (adjustable). In this case, the torque is amplified by 20 times. Assuming the torque of the valve core 13 is 0.2N / M, the tangential displacement of the valve core 13 only needs to be 10N, at which point the torque of the motor 2 is only 0.01N / M. That is to say, the 0.01N / M of the motor 2 can output the 0.2N / M of the valve core 12, and the torque is amplified by 20 times, so the current of the motor 2 can be very small. In this case, by appropriately sacrificing a little angle, assuming the motor 2 rotates 37 degrees, the valve core 13 can rotate 2.4 degrees. The motor 2 can achieve rapid positive and negative switching, mainly during the motor's start-up and braking. Currently, foreign countries have already achieved a motor rotation frequency of 300HZ at ±45 degrees, which is more than sufficient for the application in this application. The amplified motor angle is also an advantage of the motor.

[0042] The entire invention can be made into a plug-in type, with the valve body 11 inserted above the motor 2 and the linear displacement sensor inserted to the right. The angular displacement sensor is directly on the motor 2, and can be either a wet or dry type. The motor 2 can be a regular motor or a wet motor.

[0043] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A two-dimensional electro-hydraulic servo valve directly driven by an eccentric shaft motor, characterized in that: The device includes a spool valve assembly, a motor fixed to the top right side of the spool valve assembly, and a fork fixed to the right end of the valve core inside the spool valve assembly. The output shaft of the motor is an eccentric shaft, which is inserted into the valve body of the spool valve assembly, and the end of the eccentric shaft is embedded in a spherical bearing. The outer spherical surface of the spherical bearing is fitted into a groove on the upper part of the fork. The upper part of the fork has an upward-opening U-shaped groove, in which the spherical bearing is laterally fitted. The upper part of the fork has symmetrical spring grooves on both sides, and a spring positioning shaft is installed in the spring groove. A return spring is fitted in the gap between the outer circumference of the spring positioning shaft and the inner cavity of the spring groove. The lower part of the fork has a downward-opening arch-shaped groove, in which the right end of the valve core is fitted. The lower part of the fork has a horizontal circular through hole, in which a bolt is fitted. When the motor moves, the eccentric shaft of the motor drives the spherical bearing to move, thereby driving the valve core to rotate. During the rotation of the valve core, axial movement is also generated.

2. The eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: The right end of the slide valve assembly is fixedly connected to the LVDT body, the LVDT body contains an LVDT core, and the LVDT core is inserted into the right end cover of the slide valve assembly, with the end of the LVDT core inserted into the right end of the valve core.

3. The eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: The spool valve assembly includes a valve body, a valve sleeve, a valve core, a left end cap, a left valve core plug, a concentric ring, a concentric ring baffle, a first reset magnet, a second reset magnet, and a right end cap. The left end cap is bolted to the left end of the valve body, and the right end cap is bolted to the right end. A valve sleeve is installed inside the valve body, and the valve sleeve is fitted onto the valve core. A left valve core plug is embedded inside the left end of the valve core. A concentric ring is installed between the outer circumference of the right part of the valve core and the inner cavity of the right part of the valve sleeve. A concentric ring baffle is bolted to the right end of the valve sleeve, and the right end face of the concentric ring contacts the left end face of the concentric ring baffle. A second reset magnet is installed inside the right end of the concentric ring baffle. A first reset magnet is installed on the outer circumference of the right part of the valve core. The first reset magnet and the second reset magnet are magnetically coupled, and both the first reset magnet and the second reset magnet are circular ring-shaped magnets.

4. The eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve according to claim 3, characterized in that: The valve body has a semi-circular groove on the top surface of the inner cavity on the left side and the valve sleeve has a semi-circular groove on the top left side. The valve sleeve is positioned in the valve body by a positioning key.

5. The eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve according to claim 3, characterized in that: The valve body has a fork return hole and a side hole on its right side. The fork return hole contains a slotted flat-end set screw, a spring plug, and a return spring. The two ends of the return spring mate with the fork and the spring plug, respectively. The slotted flat-end set screw is threaded into the fork return hole, and its end contacts the front end face of the spring plug. The side hole contains a slotted flat-end set screw and a side hole plug. The slotted flat-end set screw is threaded into the side hole, and its end contacts the front end face of the side hole plug. The end of the side hole plug is flat, and the end of the spring plug has a circular groove that houses the return spring.

6. The eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: The motor is equipped with an angular displacement sensor.

7. The eccentric shaft motor direct-drive two-dimensional electro-hydraulic servo valve according to claim 1, characterized in that: The center of the end of the eccentric shaft of the motor is offset from the center of the upper part of the eccentric shaft by 1mm.

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