Electro-hydraulic actuator with mechanical automatic locking function

Abstract

The invention provides an electro-hydraulic actuator with a mechanical automatic locking function for driving a valve, and aims to solve the technical problem that the valve cannot be kept at a closed position once the sealing of a piston fails. The key point of the invention is that a mechanical lock is additionally arranged on the electro-hydraulic actuator. When the electro-hydraulic actuator drives the valve to be closed, the lock hole in the piston of the hydraulic main cylinder moves rightwards to the position below the lock rod along with the piston, the lock rod enters the lock hole under the action of the spring of the spring oil cylinder to lock the piston of the hydraulic main cylinder, the piston cannot move leftwards and rightwards, namely, the valve is locked in the closed state, and at the moment, even if the sealing of the piston fails, the valve can be reliably closed; the unlocking operation of the lock rod of the mechanical lock is controlled by hydraulic oil in an electro-hydraulic actuator system. The electro-hydraulic actuator has the expected effect that the reliability of the electro-hydraulic actuator is remarkably improved.

Description

Technical Field

[0001] The present invention relates to an electro-hydraulic actuator, in particular to an electro-hydraulic actuator for driving a valve. Background Art

[0002] The electro-hydraulic actuator includes a hydraulic master cylinder, which includes two oil ports on the left and right sides and a master cylinder piston. Each oil port is set on the same side of the cylinder body and leads to the same side of the cylinder cavity. The operation of the electro-hydraulic actuator driving the valve includes driving the valve to close and maintain. This requires that the piston seal of the hydraulic master cylinder as an actuator always remains effective. However, the piston seal is a consumable part and it is difficult to ensure that it is always effective. Once it fails, the electro-hydraulic actuator will not be able to keep the valve in the closed position. Summary of the invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide an electro-hydraulic actuator with mechanical automatic locking. When the master cylinder piston of the electro-hydraulic actuator is in the valve closing position, the master cylinder piston rod is locked.

[0004] The object of the present invention is achieved as follows: it comprises a hydraulic master cylinder and its master cylinder piston, cylinder bodies on left and right sides, oil ports and cylinder chambers, the oil port on one side of the cylinder body leads to the cylinder chamber on the same side, and is characterized in that: the front half of the master cylinder piston (front and back means the piston is in front and the piston rod is in the back) is in a truncated cone shape, and the rear half is in a cylindrical shape (conventional shape), the direction of the truncated cone is that the cross section (small circular surface) is in front and the bottom surface (large circular surface) is in the back, and a radial lock hole (blind hole) is arranged on the side of the cylinder; It also includes a master cylinder lock, the lower half of the lock body of the master cylinder lock is embedded on the other side of the cylinder body; a spring oil cylinder with a piston rod facing downward is arranged in the lock body, and the cylinder cavity of the cylinder is formed in the lock body, wherein the upper cavity is the spring cavity; the spring oil cylinder piston is in the shape of an inverted rounded boss (the rounded boss refers to a geometric body formed by two small and large cylinders in an up-and-down manner), and the lower half of the piston (piston rod side) is a small cylinder in the shape of an inverted rounded boss, and when the spring of the spring oil cylinder is reset, an annular oil cavity (of the spring oil cylinder) is formed between the small cylinder and the lower end cover of the spring oil cylinder; a spring oil cylinder piston rod through hole is opened in the cylinder body on the other side of the master cylinder, and the through hole leads to the cylinder cavity on the other side (the same side) and is aligned with the piston rod hole of the lower end cover of the spring oil cylinder, and the downward piston rod serves as the locking rod (lock bolt) of the master cylinder lock, and passes through the two aligned piston rod holes in sequence, and a locking rod oil channel (blind channel) is arranged in the locking rod, and two oil ports of the locking rod oil channel are respectively arranged on the lower end face and side of the locking rod; The oil port on the other side of the hydraulic master cylinder is arranged on the lock body; a three-way oil passage (in the form of a hidden passage) is also arranged in the lock body, wherein the horizontal oil passage is the unlocking oil passage, the upper vertical oil passage is the oil port oil passage, which leads to the oil port on the other side, and the lower vertical oil passage is the pressure relief oil passage, which leads to the cylinder cavity on the other side of the master cylinder; a spring-loaded one-way valve (hereinafter referred to as the one-way valve) is arranged in the oil port oil passage at the intersection of the three oil passages, and the oil passage opening of the pressure relief oil passage serves as the valve seat of the one-way valve disc, and the one-way valve disc is in the shape of an inverted rounded boss, and the inverted rounded boss-shaped disc includes a large cylinder on the top and a small cylinder on the bottom. When the spring of the one-way valve is reset, the lower end face of the small cylinder of the disc covers the valve seat, i.e., the one-way valve is closed, and the side surface of the small cylinder and the oil port oil passage form a disc annular cavity, and an axial hole is opened in the large cylinder, and the axial hole leads to the disc annular cavity; the two ends of the unlocking oil passage are respectively an annular oil cavity and a disc annular cavity, which connect the two annular cavities. At this time, the one-way valve disc is not only subjected to the downward force of the spring, but also to the oil supply from the oil port on the other side. The oil flows through the axial hole of the valve disc to the annular cavity and acts on the small cylinder, so that the small cylinder of the valve disc covers the valve seat and keeps the valve closed.

[0005] When the driven valve needs to be closed, the hydraulic master cylinder of the electro-hydraulic actuator is supplied with oil from the left oil port, and the hydraulic oil enters the cylinder chamber on the same side, pushing the master cylinder piston from left to right. The inclined surface of the master cylinder piston (the side of the frustum) gradually lifts the lock rod from low to high. Under the action of the inclined surface, the lock rod overcomes the spring force of the spring cylinder and moves upward. When the lock hole moves to the right below the lock rod (corresponding to the closed position of the driven valve) with the master cylinder piston, the lock bolt enters the lock hole under the action of the spring, so that the master cylinder piston cannot move left and right, and the master cylinder realizes mechanical self-locking, and the driven valve is closed and locked by the master cylinder.

[0006] To drive the valve to open, it needs to be unlocked first: supply oil to the right oil port on the other side of the hydraulic master cylinder. The hydraulic oil passes through the oil port oil channel, the axial hole of the one-way valve disc, the valve disc annular cavity, and the unlocking oil channel in sequence and enters the annular oil cavity, which is the oil cavity of the spring cylinder. As the hydraulic pressure in the annular oil cavity increases, the elastic force of the spring is overcome to push the spring cylinder piston upward, and the locking rod (piston rod) moves upward from the locking hole until the lower end face of the locking rod leaves the locking hole. At the same time, the side oil port of the locking rod enters the oil cavity of the spring cylinder, and the hydraulic oil in the oil cavity enters the right cylinder cavity of the master cylinder through the side oil port of the locking rod, the locking rod oil channel and the oil port on the lower end face of the locking rod, pushing the master cylinder piston to the left.

[0007] When the master cylinder changes direction and supplies oil to the left oil port and its left cylinder chamber, the hydraulic oil in the right cylinder chamber passes through the pressure relief oil passage, pushes open the valve disc of the spring-loaded one-way valve (i.e. the one-way valve opens), and flows through the oil port oil passage to the other side, i.e. the right oil port for pressure relief. The master cylinder piston moves to the right, the locking rod moves downward, and the above actions are repeated.

[0008] Compared with the prior art, the present invention has the following positive effects: it adds a master cylinder lock to the electro-hydraulic actuator, which can lock the master cylinder piston rod, thus providing a double insurance for the electro-hydraulic actuator to keep the valve closed, thereby improving the reliability of the electro-hydraulic actuator. Secondly, the unlocking operation of the master cylinder lock is controlled by the hydraulic oil in the electro-hydraulic actuator system, that is, no additional hydraulic system is added, which not only reduces costs and does not increase the volume of the original system, but also improves reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention is further described below in conjunction with the accompanying drawings.

[0010] Figure 1 It is a schematic diagram of the present invention.

[0011] Figure 2 yes Figure 1 Enlarged view of the master cylinder lock 5.

[0012] Figure 3 yes Figure 1 Top view of the .

[0013] Figure 4 yes Figure 3 CC cross-section diagram. DETAILED DESCRIPTION

[0014] See also Figure 1 It includes a hydraulic master cylinder 1, which includes a master cylinder piston 4, a left cylinder body 2 and a right cylinder body 9. The left oil port 3 on the left cylinder body leads to the cylinder cavity on the same side. The front half of the master cylinder piston 4 is in a truncated cone shape 10, and the rear half is in a conventional flat cylindrical shape. The direction of the truncated cone 10 is that the cross section is in the front and the bottom surface is in the rear. A radial lock hole 11 is arranged on the side of the flat cylinder. It also includes a master cylinder lock 5, the lower half of the master cylinder lock body 7 is embedded in the right cylinder body 9; a spring oil cylinder 6 with a piston rod facing downward is arranged in the lock body, and the cylinder cavity is formed in the lock body, see Figure 2 , the upper end cover 61 of the spring oil cylinder cooperates with the lock body 7 by a thread, the upper side cavity of the spring oil cylinder piston is a spring cavity 12, and an upper lifting rod 19 is arranged in the spring cavity 12, and the lower end of the upper lifting rod 19 is fixed on the spring oil cylinder piston 18. In this embodiment, the upper lifting rod 19 and the piston are made into one piece; the spring oil cylinder piston 18 is in the shape of an inverted rounded boss, and the piston rod side of the piston is a small cylinder 17 in the shape of an inverted rounded boss. When the spring of the spring oil cylinder is reset, an annular oil cavity 13, i.e., the oil cavity of the spring oil cylinder, is formed between the small cylinder 17 and the lower end cover 16 of the spring oil cylinder; a spring oil cylinder piston rod through hole is opened in the right cylinder body 9, and the through hole leads to the right cylinder cavity and is aligned with the piston rod hole of the lower end cover of the spring oil cylinder. The downward spring oil cylinder piston rod 15 serves as the lock rod (lock bolt) of the master cylinder lock, and passes through the two aligned piston rod holes in sequence. A Г-shaped lock rod oil passage 14 is arranged in the lock rod, and two oil ports of the lock rod oil passage are respectively arranged on the lower end surface and side of the lock rod; See also Figure 3 and 4 The right oil port 20 of the hydraulic master cylinder is arranged on the lock body 7; a ┝-shaped three-way oil passage is also arranged in the lock body 7, wherein the horizontal oil passage is the unlocking oil passage 8; the upper vertical oil passage is the oil port oil passage 28, which leads to the right oil port 20; the lower vertical oil passage is the pressure relief oil passage 23, which leads to the right cylinder cavity of the master cylinder; a spring-loaded one-way valve 27 is arranged in the oil port oil passage 28 at the intersection of the three oil passages, and the oil passage opening of the pressure relief oil passage 23 serves as the valve seat of the valve disc of the one-way valve 27. The valve disc of the one-way valve is in the shape of an inverted rounded boss, and the inverted rounded boss-shaped valve disc includes a large cylinder 25 on the top and a small cylinder 22 on the bottom. When the spring of the one-way valve is reset, the lower end surface of the small cylinder of the valve disc covers the valve seat, i.e., the one-way valve is closed. In order to achieve better sealing of the valve disc to the valve seat, the diameter of the oil port oil passage 28 is larger than the diameter of the pressure relief oil passage 23, and an inverted rounded cone-shaped pipeline plug is added to the lower end surface of the small cylinder 22. After the one-way valve is closed, the side of the small cylinder of the valve disc and the oil port oil passage 28 form a valve disc annular cavity 21, and an axial hole 26 is opened in the large cylinder. Below the axial hole 26 is a horizontal cross-shaped oil passage 24. The four oil passage openings on the edge of the cross-shaped oil passage 24 lead to the valve disc annular cavity 21, that is, the axial hole 26, the cross-shaped oil passage 24 and the valve disc annular cavity 21 are connected in sequence; the two ends of the unlocking oil passage 8 are the annular oil cavity 13 and the valve disc annular cavity 21, respectively, connecting the annular oil cavity and the valve disc annular cavity. The unlocking oil passage 8 is composed of two sections to form an L shape.

[0015] When the driven valve needs to be closed, the left oil port 3 of the hydraulic master cylinder of the electro-hydraulic actuator supplies oil, and the hydraulic oil enters the left cylinder chamber, pushing the master cylinder piston 4 from left to right. The inclined surface 10 of the master cylinder piston gradually lifts the lock rod (i.e., the spring cylinder piston rod 15) from low to high. Under the action of the inclined surface, the lock rod overcomes the spring elastic force of the spring cylinder and moves upward. When the lock hole moves to the right below the lock rod (corresponding to the closed position of the driven valve) with the master cylinder piston, the lock rod enters the lock hole 11 under the action of the spring, and the master cylinder piston cannot move left and right. The master cylinder realizes mechanical self-locking, and the driven valve is closed and locked.

[0016] To drive the valve to open, it is necessary to unlock it first: the right oil port 20 of the hydraulic master cylinder supplies oil, and the hydraulic oil passes through the oil port oil channel 28, the one-way valve disc axial hole 26, the cross-shaped oil channel 24, the disc annular cavity 21, and the unlocking oil channel 8 in sequence, and enters the annular oil chamber 13, i.e., the oil chamber of the spring oil cylinder. As the hydraulic pressure of the oil chamber increases, it overcomes the elastic force of the spring, pushes the spring oil cylinder piston upward, and the lock rod moves upward from the lock hole 11 until the lower end face of the lock rod leaves the lock hole. At the same time, the side oil port of the lock rod enters the oil chamber of the spring oil cylinder. The hydraulic oil in the oil chamber enters the right cylinder chamber of the master cylinder in sequence through the side oil port of the lock rod, the lock rod oil channel 14, and the lower end face oil port of the lock rod, pushing the master cylinder piston to the left. At this time, the one-way valve disc is not only subjected to the downward force of the spring, but also to the hydraulic pressure of the cross-shaped oil channel 24, i.e., the small cylinder, which is supplied by the right oil port 20 through the disc axial hole 26, so that the disc small cylinder covers the valve seat and keeps the valve closed.

[0017] When the master cylinder changes direction and supplies oil to the left oil port and its left cylinder chamber, the hydraulic oil in the right cylinder chamber passes through the pressure relief oil passage 23, pushes open the valve disc of the spring-loaded one-way valve (i.e., the one-way valve opens), and flows out of the right oil port 20 through the oil port oil passage 28. The master cylinder piston moves to the right, and the locking rod moves downward, repeating the above actions.

[0018] If there is no oil pressure due to power outage or other reasons, manual means is used to unlock the device, specifically, the upper end cover 61 of the spring oil cylinder is unscrewed, the spring fails, the upper lifting rod 19 is lifted upward, and the locking rod is pulled out of the lock hole to unlock the electro-hydraulic actuator.

Claims

1. An electro-hydraulic actuator with mechanical automatic locking, which includes a hydraulic master cylinder and its master cylinder piston, cylinder bodies, oil ports and cylinder chambers on the left and right sides, the oil port on one side of the cylinder body leads to the cylinder chamber on the same side, and is characterized by: The front half of the master cylinder piston is in a truncated cone shape, and the rear half is in a conventional cylindrical shape. The direction of the truncated cone is that the cross section is in the front and the bottom surface is in the rear. A radial locking hole is arranged on the side of the cylinder. It also includes a master cylinder lock, the lower half of the master cylinder lock body is embedded on the other side of the cylinder body; a spring oil cylinder with a piston rod facing downward is arranged in the lock body, and the cylinder cavity of the cylinder is formed in the lock body, wherein the upper cavity is the spring cavity; the spring oil cylinder piston is in the shape of an inverted rounded boss, and the lower half of the piston is a small cylinder in the shape of an inverted rounded boss. When the spring of the spring oil cylinder is reset, a piston annular cavity, i.e., the oil cavity of the spring oil cylinder, is formed between the small cylinder and the lower end cover of the spring oil cylinder; a piston rod through hole is opened in the cylinder body on the other side, the through hole leads to the cavity on the same side, and is aligned with the piston rod hole on the lower end cover of the spring oil cylinder. The downward piston rod serves as the locking rod of the master cylinder lock, and passes through the two aligned piston rod holes in sequence. A locking rod oil channel is arranged in the locking rod, and two oil ports of the locking rod oil channel are respectively arranged on the lower end face and the side face of the locking rod; The oil port on the other side is arranged on the lock body; a three-way oil passage is also arranged in the lock body, wherein the horizontal oil passage is the unlocking oil passage, the upper vertical oil passage is the oil port oil passage, which leads to the oil port on the other side, and the lower vertical oil passage is the pressure relief oil passage, which leads to the cylinder chamber on the other side; a spring-loaded one-way valve is arranged in the oil port oil passage at the intersection of the three oil passages, and the oil passage opening of the pressure relief oil passage serves as a valve seat for the one-way valve disc, and the one-way valve disc is in the shape of an inverted rounded boss, and the inverted rounded boss-shaped disc includes a large cylinder on the top and a small cylinder on the bottom. When the spring of the one-way valve is reset, the lower end face of the small cylinder of the disc covers the valve seat, i.e., the one-way valve is closed, and the side surface of the small cylinder and the oil port oil passage form a disc annular cavity, and an axial hole is opened in the large cylinder, and the axial hole leads to the disc annular cavity; the two ends of the unlocking oil passage are respectively the piston annular cavity and the disc annular cavity, which connect the two annular cavities.

2. The electro-hydraulic actuator with mechanical automatic locking according to claim 1, characterized in that: The upper end cover of the spring oil cylinder is matched with the lock body by a thread, a lifting rod is arranged in the spring cavity of the spring oil cylinder, and the lower end of the lifting rod is fixed on the piston of the spring oil cylinder.

3. The electro-hydraulic actuator with mechanical automatic locking according to claim 1 or 2, characterized in that: The large cylindrical opening of the inverted boss-shaped one-way valve disc has an axial hole, and below the axial hole is a horizontal cross-shaped oil passage, and four oil passage openings on the edge of the cross-shaped oil passage lead to the disc annular cavity, that is, the axial hole, the cross-shaped oil passage and the disc annular cavity are connected in sequence.

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