Parallel asymmetric actuator cylinder sealing durability reinforcement test device and method

Abstract

This invention pertains to hydraulic actuator testing and verification technology, specifically a test apparatus and method for enhancing the sealing durability of a parallel asymmetric actuator cylinder. The test apparatus includes: a parallel asymmetric actuator cylinder under test, a variable load device, a controller, and a high-temperature oil source. The parallel asymmetric actuator cylinder comprises: an actuator cylinder, a piston rod assembly, and a bushing. The bottom end of the actuator cylinder is fixed to the test bench via an end ring. The piston rod assembly engages with the actuator cylinder, reciprocating within the actuator cylinder. The bushing is installed at the actuator cylinder port, achieving a movable seal between the piston rod assembly and the actuator cylinder. A tailstock is provided at the end of the piston rod assembly outside the actuator cylinder. The variable load device contacts the tailstock, applying pressure to it. The inner cavity of the actuator cylinder is connected to the high-temperature oil source. The controller sends control commands to the variable load device.

Description

Technical Field

[0001] This invention pertains to hydraulic actuator testing and verification technology, and relates to a test device and method for enhancing the durability of a parallel asymmetric actuator cylinder seal. Background Technology

[0002] Generally, dynamic sealing performance testing of actuators is conducted during the product qualification testing phase, using durability testing methods. This involves applying different temperatures, motion commands, and load spectra to the actuator to confirm whether the dynamic seal meets the requirements. The disadvantages of this method are: the testing and verification cycle is extremely long, consuming significant manpower and resources; and if the actuator's sealing performance fails to meet requirements during testing, repeated testing is necessary, delaying the development schedule. During the design and development of actuators, there is a need to find a method that can verify and confirm different sealing designs early in the design process, quickly revealing design weaknesses, avoiding problems later, and improving the overall quality of actuator development.

[0003] Currently, the upper limit of the actuator's maximum operating temperature is used for reciprocating break-in tests to quickly obtain the sealing durability performance of the servo motor. Compared with conventional sealing durability testing methods, this method can improve testing efficiency. Conventional symmetrical and tandem actuators have relatively small lateral forces, making the above method suitable for them. Parallel asymmetrical actuators are a special type of actuator, exhibiting larger lateral forces during reciprocating motion, which vary at different movement positions. Besides temperature and wear stroke, the lateral forces on the actuator are also relevant to the actuator's sealing durability. Therefore, it is necessary to find an accelerated durability testing method that can quickly verify the sealing durability of parallel asymmetrical actuators. Summary of the Invention

[0004] Objective of the Invention: This invention, through an improved accelerated durability testing device and method, enables rapid verification of the reliability of sealing solutions and comparison of the reliability of different sealing solutions. This provides a quick basis for decision-making in the design process, effectively accelerating research and development.

[0005] Technical solution:

[0006] In the first aspect, a test device for enhancing the sealing durability of a parallel asymmetric actuator is provided, comprising: the parallel asymmetric actuator to be tested, a variable load device, a controller, and a high-temperature oil source;

[0007] The parallel asymmetric actuator includes: actuator, piston rod assembly, and bushing;

[0008] The bottom end of the actuator cylinder is fixed to the test bench by an end ring. The piston rod assembly cooperates with the actuator cylinder, and the piston rod assembly reciprocates inside the actuator cylinder. The bushing is installed at the port of the actuator cylinder to achieve a movable seal between the piston rod assembly and the actuator cylinder. A tailstock is provided at the end of the piston rod assembly outside the actuator cylinder. The variable load device contacts the tailstock and applies pressure to the tailstock. The inner cavity of the actuator cylinder is connected to a high-temperature oil source. The controller is used to send control commands to the variable load device.

[0009] Furthermore, the test apparatus also includes: a reversing valve;

[0010] The inner cavity of the actuator cylinder is connected to a high-temperature oil source through a reversing valve.

[0011] Furthermore, the experimental apparatus also includes: a measuring cup;

[0012] A measuring cup is placed below the actuator port to collect oil leakage between the piston rod assembly and the bushing.

[0013] Furthermore, during the test, the parallel asymmetric actuators were installed laterally, and the pressure applied by the variable load device was the lateral load.

[0014] Furthermore, the side load range is 30%-80% of the piston output force.

[0015] In a second aspect, a method for enhancing the durability of a parallel asymmetric actuator seal is provided, employing the test apparatus described in any one of the first aspects, characterized in that the method comprises:

[0016] Step 1: Use a high-temperature oil source to supply pressure to the actuator. The temperature of the high-temperature oil source should not exceed the maximum operating temperature that the actuator can withstand.

[0017] Step 2: Use a variable load device to adjust the magnitude of the spring force, change the load acting on the tailstock of the actuator, and achieve the purpose of subjecting the bushing to lateral load during the movement of the actuator.

[0018] Step 3: Adjust the synchronization of the control valve to make the lateral force of the actuator cylinder the ultimate lateral force;

[0019] Step 4: Apply a positive bias command to the actuator to make the actuator reciprocate cyclically near the extension limit position;

[0020] Step 5: Use a measuring cup to test the external leakage at the dynamic seal of the actuator until the external leakage reaches the target value. The test is then complete.

[0021] Furthermore, the reciprocating cyclical motion is carried out at maximum stroke and maximum speed.

[0022] Furthermore, the formula for calculating the lateral force F is:

[0023] F = M + L;

[0024] M = (f1 - f2) × d;

[0025] f1-f2=(P1-P2)×S;

[0026] f1-f2=ΔP×S;

[0027] ΔP = P1 - F2;

[0028] Where M represents the lateral bending moment, L represents the piston rod support length, S represents the piston area under pressure; P1 and P2 represent the actual pressure in the two chambers of the parallel asymmetric actuator, d represents the distance between the two piston rod components, f1 and f2 represent the forces after the two piston rods are compressed, and ΔP is the pressure difference.

[0029] Beneficial effects:

[0030] This invention can quickly obtain the durability of parallel asymmetric actuators. The test method is simple and easy to implement, which can significantly shorten the test time and improve the R&D efficiency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a test device for enhancing the durability of a parallel asymmetric actuator seal.

[0032] Figure 2 This is a schematic diagram of a test device for enhancing the durability of a parallel asymmetric actuator seal. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0035] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] This invention provides a test device for enhancing the durability of parallel asymmetric actuator seals, such as... Figure 1 As shown, it includes: the parallel asymmetric actuator under test, the variable load device 4, the controller, and the high-temperature oil source 7;

[0037] The parallel asymmetric actuator includes: actuator 1, piston rod assembly 2, and bushing 3;

[0038] The bottom end of the actuator cylinder is fixed to the test bench by an end ring 9. The piston rod assembly cooperates with the actuator cylinder, and the piston rod assembly reciprocates within the actuator cylinder. A bushing is installed at the port of the actuator cylinder to achieve a movable seal between the piston rod assembly and the actuator cylinder. A tailstock 5 is provided at the end of the piston rod assembly outside the actuator cylinder. A variable load device contacts the tailstock and applies pressure to the tailstock. The inner cavity of the actuator cylinder is connected to a high-temperature oil source. The components are connected to each other via an oil passage 6.

[0039] By applying high temperature and setting a high resistance force to the actuator, a rapid break-in test is conducted at the extension limit position to obtain the verification results of the actuator's sealing durability.

[0040] The actuator experiences its maximum lateral force at its extended limit position. Applying a positive limit bias command causes the actuator cylinder to reciprocate at this limit position. By introducing a large conflicting force between the two actuator cylinders, a larger lateral force is achieved between the actuator cylinder piston rod and the bushing. Within the actuator's motion capability range, the actuator cylinder's motion frequency is increased as much as possible. Tests are conducted at the highest possible oil temperature within the maximum operating temperature range of the sealing ring.

[0041] The specific implementation steps are as follows:

[0042] Step 1: Use a high-temperature oil source to supply pressure to the actuator. The temperature of the high-temperature oil source should not exceed the maximum operating temperature that the actuator can withstand, such as 120℃.

[0043] Step 2: Use a variable load device to adjust the spring force and change the load acting on the tailstock of the actuator cylinder, so that the bushing is subjected to lateral load during the movement of the actuator cylinder.

[0044] Step 3: Adjust the synchronization of the control valve to make the lateral force of the actuator cylinder the ultimate lateral force.

[0045] Step 4: Apply a positive bias command to the actuator to make the actuator reciprocate in a cyclical motion near the extension limit position.

[0046] Step 5: Use a measuring cup to test the external leakage at the dynamic seal of the actuator until the external leakage reaches the target value. The test is then complete.

[0047] The pressure difference between the two chambers of the actuator is generally 30% to 80% of the working pressure Ps. Figure 2 As can be seen in the example, the pressure difference at this time is:

[0048] ΔP=P1-F2 (1)

[0049] At this point, the magnitude of the conflicting forces is:

[0050] f1-f2ΔP×8(P1-P2)×8 (2)

[0051] The lateral bending moment M caused by the conflicting forces is:

[0052] M=(f1-f2)×d=(P1-P2·S·d (3)

[0053] The magnitude of the lateral load F caused by the lateral bending moment and the support length is:

[0054] F=M+L=(P1-P2)·S·d / L (4)

[0055] In the formula, the size of L is determined by the piston position of the servo product: when the servo is in the maximum retracted position, L is the largest and the lateral load F is the largest; when the servo is in the maximum extended position, L is the smallest and the lateral load F is the smallest.

[0056] Where Ps represents the oil source pressure (servo motor working pressure), P1 and P2 represent the actual pressure of the two chambers, S represents the piston area under pressure, L represents the piston rod support length, d represents the distance between the two piston rods, f1 and f2 represent the force of the piston rod after being compressed, and M represents the lateral bending moment caused by the inequality of f1 and f2.

[0057] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be included within the scope of protection of the present invention.

Claims

1. A parallel asymmetric ram seal durability enhancement test device, characterized by, include: The tested components are a parallel asymmetric actuator, variable load device, controller, and high-temperature oil source. The parallel asymmetric actuator includes: actuator, piston rod assembly, and bushing; The bottom end of the actuator cylinder is fixed to the test bench by an end ring. The piston rod assembly cooperates with the actuator cylinder, and the piston rod assembly reciprocates inside the actuator cylinder. A bushing is installed at the port of the actuator cylinder to achieve a movable seal between the piston rod assembly and the actuator cylinder. A tailstock is provided at the end of the piston rod assembly outside the actuator cylinder. The variable load device contacts the tailstock and applies pressure to the tailstock. The inner cavity of the actuator cylinder is connected to a high-temperature oil source. The controller is used to send control commands to the variable load device. The test apparatus also includes: a reversing valve; The inner cavity of the actuator cylinder is connected to a high-temperature oil source through a reversing valve; The experimental setup also includes: a measuring cup; A measuring cup is placed below the actuator port to collect oil leakage between the piston rod assembly and the bushing.

2. The test device of claim 1, wherein During the test, the parallel asymmetric actuators were installed laterally, and the pressure applied by the variable load device was the lateral load.

3. The test device of claim 2, wherein, The side load range is 30%-80% of the piston output force.

4. A test method for enhancing the durability of a parallel asymmetric actuator seal, characterized in that, The method using the test apparatus according to any one of claims 1-3 is characterized in that it comprises: Step 1: Use a high-temperature oil source to supply pressure to the actuator, ensuring that the temperature of the high-temperature oil source does not exceed the maximum operating temperature that the actuator can withstand; Step 2: Use a variable load device to adjust the magnitude of the spring force, change the load acting on the tailstock of the actuator, and achieve the purpose of subjecting the bushing to lateral load during the movement of the actuator. Step 3: Adjust the synchronization of the control valve to make the lateral force of the actuator cylinder the ultimate lateral force; Step 4: Apply a positive bias command to the actuator to make the actuator reciprocate cyclically near the extension limit position; Step 5: Use a measuring cup to test the external leakage at the dynamic seal of the actuator until the external leakage reaches the target value. The test is then complete.

5. The method according to claim 4, characterized in that, The reciprocating cyclical motion is carried out at the maximum stroke and maximum speed.

6. The method according to claim 5, characterized in that, The formula for calculating the lateral force F is: F = M + L; M = (f1 - f2) × d; f1-f2=(P1-P2)×S; f1-f2=ΔP×S; ΔP = P1 - P2; Where M represents the lateral bending moment, L represents the piston rod support length, S represents the piston area under pressure; P1 and P2 represent the actual pressure in the two chambers of the parallel asymmetric actuator, d represents the distance between the two piston rod components, f1 and f2 represent the forces after the two piston rods are compressed, and ΔP is the pressure difference.

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