Floating type metal clearance sealing servo actuator

Abstract

The invention relates to the technical field of mechanical testing, and provides a floating type metal clearance sealing servo actuator which is characterized in that a piston rod, a cylinder body, an end cover, an overlapped end cover and a metal clearance sealing ring are arranged, the piston rod is installed in the cylinder body, and the end cover is located at the end of the cylinder body and surrounds a part of a rod body of the piston rod installed in the cylinder body; the stacked end cover is located on the side edge of the end cover and locked with the cylinder body and the end cover through a locking device, the stacked end cover surrounds a part of a rod body of the piston rod installed in the cylinder body, the stacked end cover, the end cover and the cylinder body form a sealing ring assembling groove on the periphery of the piston rod after being locked, and the metal gap sealing ring is a rigid body. And the metal gap sealing ring is assembled in the sealing ring assembling groove in a floating manner and is used for sealing hydraulic oil overflowing along the superposed end cover in the cylinder body, so that the piston motion damping of the servo actuator is reduced, the test frequency and precision of the fatigue testing machine are improved, and the service life of the fatigue testing machine is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of mechanical testing machines, such as fatigue testing machines, hydraulic presses, loading devices, etc. Specifically, it relates to a floating metal gap sealing servo actuator. Background Art

[0002] The performance of the servo actuator directly determines the performance of the fatigue testing machine. The core technical indicators for measuring the servo actuator usually include the response frequency of the piston movement, loading accuracy, sealing, and service life. Among them, sealing technology is the key difficulty of the servo actuator. The sealing of traditional servo actuators is mainly achieved by using sealing rings made of rubber, polyurethane, polytetrafluoroethylene and other materials. In order to ensure its good sealing, the sealing ring must be in a state of extrusion between the piston rod and the piston. At the same time, the piston rod is also subject to the elastic force of the sealing ring, resulting in a very large damping of the piston rod movement. The fatigue load response frequency is greatly limited, and the speed and displacement of its movement are difficult to control, resulting in the test curve being far from the theoretical curve of the software, and the test accuracy cannot be guaranteed; the response frequency is low, and the test frequency is generally below 30Hz; fatigue movement under high damping, the piston rod and the sealing ring are prone to wear and failure, and the service life cannot be guaranteed.

[0003] In summary, the sealing technology of the existing servo actuator has the problem of large piston motion damping, which leads to technical problems such as low test frequency, low test accuracy and short service life of the fatigue testing machine. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art to at least a certain extent, and to provide a floating metal gap sealed servo actuator to reduce the piston motion damping of the servo actuator and improve the test frequency, accuracy and service life of the fatigue testing machine.

[0005] The floating metal gap sealing servo actuator provided by the present invention comprises:

[0006] A piston rod, the piston rod being used for assembly with a cylinder body of a servo actuator;

[0007] A cylinder body, wherein a portion of the piston rod is loaded into the cylinder body, and another portion of the piston rod extends from the inside of the cylinder body to the outside of the cylinder body;

[0008] An end cover, located at the end of the cylinder body and surrounding a portion of the piston rod inserted into the cylinder body;

[0009] The stacked end cover is located at the side of the end cover and is locked with the cylinder body and the end cover through a locking device. The stacked end cover surrounds a portion of the piston rod inserted into the cylinder body. After the stacked end cover, the end cover and the cylinder body are locked, a sealing ring assembly groove is formed around the piston rod.

[0010] The metal gap sealing ring is a rigid body, and the metal gap sealing ring is floatingly assembled in the sealing ring assembly groove, and is used to seal the hydraulic oil overflowing from the cylinder along the stacked end cover.

[0011] Furthermore, the locking device is a screw, and the screw locks the cylinder body, the stacked end cover, and the end cover together.

[0012] Furthermore, the floating metal gap sealing servo actuator also includes a first O-ring; the cylinder body includes an oil inlet hole, and the oil inlet hole is connected to the piston rod; the first O-ring is arranged at the gap position formed by the contact between the stacked end cover and the cylinder body, and is located on the side of the oil inlet hole; the sealing ring assembly groove supports disassembly into two parts to install the metal gap sealing ring, and the two parts after disassembly include the stacked end cover and the end cover, and the first O-ring is used to prevent the hydraulic oil from leaking during the connection process between the stacked end cover and the end cover.

[0013] Furthermore, both ends of the metal gap sealing ring include a second O-ring, and the second O-ring is used to prevent the hydraulic oil from leaking from the end of the metal gap sealing ring.

[0014] Furthermore, the second O-ring is also used to form an elastic support between the metal gap sealing ring and the stacked end cover, and to form an elastic support between the metal gap sealing ring and the end cover.

[0015] Furthermore, the inner diameter of the metal gap sealing ring is based on the axis of the piston rod, and a fitting gap is formed between the metal gap sealing ring and the piston rod; the outer diameter of the metal gap sealing ring is not constrained, and is in a floating state through the elastic support of the second O-ring, and automatically adjusts its radial position following the piston rod.

[0016] Furthermore, the hydraulic oil passes through the fitting gap between the inner diameter of the metal gap sealing ring and the piston rod, and the hydraulic oil passing through the fitting gap forms a uniform flowing oil film in the fitting gap.

[0017] Furthermore, a low-pressure sealing ring assembly groove for assembling a low-pressure sealing ring is formed between the end cover and the piston rod, and the low-pressure sealing ring assembly groove is located in the axial direction of the sealing ring assembly groove; the flowing oil film leaks from the fitting gap and flows toward the low-pressure sealing ring, and the flowing oil film after leakage is pressure-free and is blocked by the low-pressure sealing ring to stop further leakage.

[0018] Furthermore, the floating metal gap seal servo actuator also includes an overflow hole; the overflow hole is connected to the oil tank and communicated to the flow position of the flowing oil film blocked by the low-pressure sealing ring, and the flowing oil film blocked by the low-pressure sealing ring is connected back to the oil tank.

[0019] Furthermore, the overflow hole is connected between the cylinder body, the stacked end cover, and the end cover to form an interconnecting channel to collect the hydraulic oil. The connection process is blocked by a third O-ring arranged at the connection gap to avoid overflow from the connection gap.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The floating metal gap sealing servo actuator provided by the present invention is provided with a piston rod, a cylinder body, an end cover, a superimposed end cover and a metal gap sealing ring. A part of the rod body of the piston rod is loaded into the cylinder body, and another part of the rod body of the piston rod extends from the inside of the cylinder body to the outside of the cylinder body. The end cover is located at the end of the cylinder body and surrounds the part of the rod body of the piston rod loaded into the cylinder body. The superimposed end cover is located at the side of the end cover and is locked with the cylinder body and the end cover through a locking device. The superimposed end cover surrounds the part of the rod body of the piston rod loaded into the cylinder body. After the superimposed end cover, the end cover and the cylinder body are locked, a sealing ring assembly groove is formed around the piston rod. The metal gap sealing ring is a rigid body. The metal gap sealing ring is floatingly assembled in the sealing ring assembly groove and is used to seal the hydraulic oil overflowing from the cylinder body along the superimposed end cover, thereby reducing the piston motion damping of the servo actuator and improving the test frequency, accuracy and service life of the fatigue testing machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.

[0023] Figure 1 It is a cross-sectional structural schematic diagram of a floating metal gap sealing servo actuator according to an embodiment of the present invention;

[0024] Figure 2 It is a partial structural schematic diagram of the cross-sectional structure of the floating metal gap sealing servo actuator according to an embodiment of the present invention;

[0025] Figure 3 yes Figure 2 A schematic diagram of an enlarged structure of part a embodied in the local cross-sectional structure;

[0026] Figure 4 The invention discloses a schematic diagram of an assembly structure of a floating metal gap sealing servo actuator according to an embodiment of the invention.

[0027] Description of reference numerals:

[0028] 1. Cylinder body;

[0029] 2. Piston rod

[0030] 3. Stacking end caps;

[0031] 4. End cap;

[0032] 5. Locking device;

[0033] 6. Second oil inlet hole;

[0034] 7. First oil inlet hole;

[0035] 8. Overflow hole;

[0036] 9. First O-ring;

[0037] 10. The third O-ring;

[0038] 11. Second O-ring;

[0039] 12. Metal gap sealing ring;

[0040] 13. Guide belt;

[0041] 14. Low pressure sealing ring;

[0042] 15. Dust ring. DETAILED DESCRIPTION

[0043] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar methods or methods having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention. All other embodiments obtained by ordinary technicians in the field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0044] See also Figure 1-Figure 4 An embodiment of the present invention provides a floating metal gap sealing servo actuator, which includes a piston rod 2, a cylinder body 1, an end cover 4, an overlapping end cover 3 and a metal gap sealing ring 12. The piston rod 2 is used to be assembled with the cylinder body 1 of the servo actuator; a portion of the piston rod 2 is installed in the cylinder body 1, and the other portion of the piston rod 2 extends from the inside of the cylinder body 1 to the outside of the cylinder body 1; the end cover 4 is located at the end of the cylinder body 1 and surrounds the portion of the piston rod 2 installed in the cylinder body 1; the superimposed end cover 3 is located on the side of the end cover 4, and is locked with the cylinder body 1 and the end cover 4 through a locking device 5, and the superimposed end cover 3 surrounds the portion of the piston rod 2 installed in the cylinder body 1; after the superimposed end cover 3 and the end cover 4 are locked with the cylinder body 1, a sealing ring assembly groove is formed around the piston rod 2; the metal gap sealing ring 12 is a rigid body, and the metal gap sealing ring 12 is floatingly assembled in the sealing ring assembly groove, and is used to seal the hydraulic oil overflowing from the cylinder body 1 along the superimposed end cover 3.

[0045] It should be noted that, in the prior art, the sealing of the servo actuator is mainly achieved by using sealing rings made of rubber, polyurethane, polytetrafluoroethylene and other materials. To ensure its good sealing performance, the sealing ring must be in a contact state between the piston rod 2 and the piston. At the same time, the piston rod 2 is also subjected to the elastic force of the sealing ring, resulting in a very large damping of the movement of the piston rod 2, and its fatigue load response frequency is greatly limited. Its movement speed and displacement are also difficult to control, resulting in a large difference between the test curve and the software theoretical curve, and the test accuracy cannot be guaranteed; the response frequency is low, and the test frequency is generally below 30Hz; under fatigue movement with high damping, the piston rod 2 and the sealing ring are prone to wear and failure, and their service life cannot be guaranteed. In this embodiment, by providing a piston rod 2, a cylinder body 1, an end cover 4, a superimposed end cover 3 and a metal gap sealing ring 12, a portion of the rod body of the piston rod 2 is loaded into the cylinder body 1, and another portion of the rod body of the piston rod 2 extends from the inside of the cylinder body 1 to the outside of the cylinder body 1, the end cover 4 is located at the end of the cylinder body 1 and surrounds the portion of the rod body of the piston rod 2 loaded into the cylinder body 1, the superimposed end cover 3 is located on the side of the end cover 4, and is locked with the cylinder body 1 and the end cover 4 through a locking device 5, the The stacked end cover 3 surrounds the portion of the piston rod 2 inserted into the cylinder body 1. After the stacked end cover 3, the end cover 4 and the cylinder body 1 are locked, a sealing ring assembly groove is formed around the piston rod 2. The metal gap sealing ring 12 is a rigid body. The metal gap sealing ring 12 is floatingly assembled in the sealing ring assembly groove to seal the hydraulic oil overflowing from the cylinder body 1 along the stacked end cover 3, thereby reducing the piston motion damping of the servo actuator and improving the test frequency, accuracy and service life of the fatigue testing machine.

[0046] It should also be noted that, in the present embodiment, after the hydraulic oil is filled inside the sealing ring assembly groove, the metal gap sealing ring 12 floats in the sealing ring assembly groove, and does not make hard contact with the piston rod 2, and does not squeeze the piston rod 2 and the piston. At the same time, the piston rod 2 is not subjected to the elastic force of the sealing ring. Therefore, the motion damping of the piston rod 2 is greatly reduced, and the degree of limitation of its fatigue load response frequency is greatly reduced. The speed and displacement of its movement can be more easily controlled, thereby greatly reducing the gap between the test curve and the software theoretical curve, ensuring the test accuracy, improving the response frequency, avoiding the wear and failure of the piston rod 2 and the sealing ring, and ensuring the service life.

[0047] In some preferred embodiments, the locking device 5 is a screw, and the screw locks the cylinder body 1, the stacked end cover 3, and the end cover 4 into one. It should be noted that in this embodiment, the inner holes of the cylinder body 1, the stacked end cover 3, and the end cover 4 can be cylindrical, and the external shapes can be various shapes, such as cylindrical, square, and other special shapes. When the cylinder body 1, the stacked end cover 3, and the end cover 4 are locked into one by screws, multiple screws can be used to penetrate the cylinder body 1, the stacked end cover 3, and the end cover 4 to lock them for a week, and the cylinder body 1, the stacked end cover 3, and the end cover 4 are locked. It can be understood that the screw as the locking device 5 is not only low in cost, but also the locked cylinder body 1, the stacked end cover 3, and the end cover 4 can be firmly connected, and it is also convenient to disassemble.

[0048] In some preferred embodiments, the floating metal gap seal servo actuator further includes a first O-ring 9; the cylinder body 1 includes an oil inlet hole, the oil inlet hole is connected to the piston rod 2; the first O-ring 9 is arranged at the gap formed by the contact between the stacked end cover 3 and the cylinder body 1, and is located on the side of the oil inlet hole; the seal ring assembly groove supports disassembly into two parts to install the metal gap seal ring 12, and the two parts after disassembly include the stacked end cover 3 and the end cover 4, and the first O-ring 9 prevents the hydraulic oil from leaking out during the connection process of the stacked end cover 3 and the end cover 4. It should be noted that the metal gap seal ring 12 is different from the rubber seal ring that can be installed into the seal ring assembly groove by pressing and deforming. The metal gap seal ring 12 is a rigid body, and the seal ring assembly groove needs to be disassembled into two parts before it can be installed. After disassembly, the end cover 3 and the end cover 4 are stacked, and the first O-ring 9 prevents the hydraulic oil from leaking out during the connection process of the two parts. Exemplarily, the oil inlet hole may include a first oil inlet hole 7 and a second oil inlet hole 6 , and the first O-ring 9 may be disposed at a gap formed by the stacked end cover 3 and the cylinder body 1 , located on the side of the first oil inlet hole 7 .

[0049] In some preferred embodiments, the two ends of the metal gap seal ring 12 include a second O-ring 11, and the second O-ring 11 is used to prevent the hydraulic oil from leaking from the end of the metal gap seal ring 12. The second O-ring 11 is also used to form an elastic support between the metal gap seal ring 12 and the stacked end cover 3, and to form an elastic support between the metal gap seal ring 12 and the end cover 4. The inner diameter of the metal gap seal ring 12 is based on the axis of the piston rod 2, and a matching gap is formed between the piston rod 2; the outer diameter of the metal gap seal ring 12 is not constrained, and forms a floating state through the elastic support of the second O-ring 11, and automatically adjusts its radial position following the piston rod 2. It should be noted that the two ends of the metal gap seal ring 12 are the second O-rings 11, and the second O-rings 11 can prevent the hydraulic oil from leaking from the end of the metal gap seal ring 12, and also support the two ends of the metal gap seal ring 12 from hard contact with the stacked end cover 3 and the end cover 4, forming an elastic support, and will not be stuck by the end face when automatically adjusting the radial position. The inner diameter of the metal gap seal ring 12 and the piston rod 2 are matched with a high-precision gap, which is based on the axis of the piston rod 2. The outer diameter of the metal gap seal ring 12 is not constrained. With the elastic support of the second O-ring 11, the metal gap seal ring 12 forms a floating state, automatically adjusts its radial position following the piston rod 2, and can form a circle of uniform gap. The damping between the metal gap seal ring 12 and the piston rod 2 is very small and there is no wear. Low damping can increase the response frequency of the reciprocating motion of the piston, reduce wear, and increase the service life.

[0050] In some preferred embodiments, the fitting gap between the inner diameter of the metal gap seal ring 12 and the piston rod 2 passes through the hydraulic oil, and the hydraulic oil passing through the fitting gap forms a uniform flowing oil film in the fitting gap. A low-pressure seal ring 14 assembly groove for assembling the low-pressure seal ring 14 is also formed between the end cover 4 and the piston rod 2, and the low-pressure seal ring 14 assembly groove is located in the axial direction of the seal ring assembly groove; the flowing oil film leaks from the fitting gap and flows toward the low-pressure seal ring 14. The flowing oil film after leakage has no pressure and is blocked by the low-pressure seal ring 14 to stop further leakage. The floating metal gap seal servo actuator also includes an overflow hole 8; the overflow hole 8 is connected to the oil tank and is connected to the flow position of the flowing oil film blocked by the low-pressure seal ring 14, and the flowing oil film blocked by the low-pressure seal ring 14 is connected back to the oil tank. The overflow hole 8 is connected between the cylinder body 1, the stacked end cover 3, and the end cover 4 to form an intercommunication channel to collect the hydraulic oil. The connection process is blocked by the third O-ring 10 set at the connection gap to prevent overflow from the connection gap. It should be noted that the inner diameter of the metal gap seal ring 12 and the piston rod 2 are high-precision clearance fits, and the space through which the hydraulic oil can pass is very limited, that is, it plays a sealing role on the hydraulic oil, but a certain amount of hydraulic oil will still seep out of the fit gap. When the hydraulic oil seeps out, a uniform oil film will be formed in the fit gap. The gap and the oil film are ideal conditions for the movement of the piston rod 2. The gap can avoid the extrusion force between the piston rod 2 and the metal gap seal ring 12, and the flowing oil film can provide good lubrication. The flowing oil film seeps out of the gap, that is, leaks. The leaked hydraulic oil has no pressure and is blocked by the low-pressure seal ring 14 and will not continue to leak out. The pressure-free hydraulic oil will not squeeze the low-pressure seal ring 14, and the friction between the un-squeezed low-pressure seal ring 14 and the piston rod 2 is extremely small. The leaked hydraulic oil is connected back to the oil tank through the overflow hole 8. The overflow hole 8 forms an interconnected channel in the cylinder body 1, the stacked end cover 3, and the end cover 4 to collect the hydraulic oil. During the connection process, there is a third O-ring 10 to prevent the hydraulic oil from overflowing from the connection gap.

[0051] In some further embodiments, the floating metal gap seal servo actuator further includes a guide belt 13, which is arranged between the piston rod 2 and the superimposed end cover 3, and between the piston rod 2 and the end cover 4, and is used to support the piston rod 2 to avoid hard contact between the piston rod 2 and the superimposed end cover 3 and the end cover 4. It should be noted that the guide belt 13 is arranged between the piston rod 2 and the superimposed end cover 3, and between the piston rod 2 and the end cover 4, and is used to support the piston rod 2 to avoid hard contact between the piston rod 2 and the superimposed end cover 3 and the end cover 4, thereby providing good lubricity, reducing the damping between the superimposed end cover 3, the end cover 4 and the piston rod 2, improving the response frequency of the reciprocating motion of the piston, reducing wear, and improving the service life.

[0052] In some further embodiments, the floating metal gap sealing servo actuator further includes a dust ring 15 ; the dust ring 15 is disposed between the piston rod 2 and the end cover 4 to prevent external dust from entering the cylinder body 1 , thereby providing dust protection for the interior of the cylinder body 1 .

[0053] The above is a description of the technical solution provided by the present invention. For those skilled in the art, according to the ideas of the embodiments of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A floating metal gap seal servo actuator, characterized in that: include: A piston rod, the piston rod being used for assembly with a cylinder body of a servo actuator; A cylinder body, wherein a portion of the piston rod is loaded into the cylinder body, and another portion of the piston rod extends from the inside of the cylinder body to the outside of the cylinder body; An end cover, located at the end of the cylinder body and surrounding a portion of the piston rod inserted into the cylinder body; The stacked end cover is located at the side of the end cover and is locked with the cylinder body and the end cover through a locking device. The stacked end cover surrounds a portion of the piston rod inserted into the cylinder body. After the stacked end cover, the end cover and the cylinder body are locked, a sealing ring assembly groove is formed around the piston rod. The metal gap sealing ring is a rigid body, and the metal gap sealing ring is floatingly assembled in the sealing ring assembly groove, and is used to seal the hydraulic oil overflowing from the cylinder along the stacked end cover.

2. The floating metal gap seal servo actuator according to claim 1, characterized in that: The locking device is a screw, and the screw locks the cylinder body, the stacked end cover, and the end cover together.

3. The floating metal gap seal servo actuator according to claim 1, characterized in that: Also includes: The first O-ring; the cylinder body includes an oil inlet hole, and the oil inlet hole is connected to the piston rod; the first O-ring is arranged at the gap position formed by the contact between the stacked end cover and the cylinder body, and is located on the side of the oil inlet hole; the sealing ring assembly groove supports disassembly into two parts to install the metal gap sealing ring, and the two parts after disassembly include the stacked end cover and the end cover. The first O-ring is used to prevent the hydraulic oil from leaking during the connection process between the stacked end cover and the end cover.

4. The floating metal gap seal servo actuator according to claim 1, characterized in that: Both ends of the metal gap sealing ring include second O-rings, and the second O-rings are used to prevent the hydraulic oil from leaking from the ends of the metal gap sealing ring.

5. The floating metal gap seal servo actuator according to claim 4, characterized in that: The second O-ring is also used to form an elastic support between the metal gap sealing ring and the stacked end cover, and to form an elastic support between the metal gap sealing ring and the end cover.

6. The floating metal gap seal servo actuator according to claim 5, characterized in that: The inner diameter of the metal gap sealing ring is based on the axis of the piston rod, and a fitting gap is formed between the metal gap sealing ring and the piston rod; the outer diameter of the metal gap sealing ring is not constrained, and is in a floating state through the elastic support of the second O-ring, and automatically adjusts its radial position following the piston rod.

7. The floating metal gap seal servo actuator according to claim 6, characterized in that: The hydraulic oil passes through the fitting gap between the inner diameter of the metal gap sealing ring and the piston rod, and the hydraulic oil passing through the fitting gap forms a uniform flowing oil film in the fitting gap.

8. The floating metal gap seal servo actuator according to claim 7, characterized in that: A low-pressure sealing ring assembly groove for assembling a low-pressure sealing ring is also formed between the end cover and the piston rod, and the low-pressure sealing ring assembly groove is located in the axial direction of the sealing ring assembly groove; the flowing oil film leaks from the fitting gap and flows toward the low-pressure sealing ring. The flowing oil film after leakage is pressure-free and is blocked by the low-pressure sealing ring to stop further leakage.

9. The floating metal gap seal servo actuator according to claim 8, characterized in that: It also includes an overflow hole; the overflow hole is connected to the oil tank and communicated to the flow position of the flowing oil film blocked by the low-pressure sealing ring, and the flowing oil film blocked by the low-pressure sealing ring is connected back to the oil tank.

10. The floating metal gap seal servo actuator according to claim 9, characterized in that: The overflow hole is connected between the cylinder body, the stacked end cover, and the end cover to form an interconnected channel to collect the hydraulic oil. The connection process is blocked by a third O-ring arranged at the connection gap to avoid overflow from the connection gap.

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