Hydraulic automatic pressing and expanding clamp for thin-wall casing machining

Abstract

The invention provides a hydraulic automatic pressing and expanding clamp for machining a thin-wall casing, which comprises five parts: the first part is a basic part which consists of a lower base and an upper base, forms a framework of the clamp, is internally provided with a built-in hydraulic oil path and becomes a connection foundation of other parts; the second part is a positioning assembly, the third part is a pressing assembly, the fourth part is a pre-alignment mechanism, the fifth part is a zero-point positioning interface positioning system, the zero-point positioning interface positioning system is composed of nine zero-point positioning joints, and the zero-point positioning interface positioning system is matched with a foundation seat with a zero-point positioner on a machine tool to achieve quick replacement of the clamp. The clamp has the advantages that the clamping alignment time of parts is shortened, high flexibility of the clamp is achieved, machining can be paused at any time for detection or part replacement machining in the midway, the production efficiency is improved, and the clamp has reference significance for numerical control machining of similar thin-wall annular parts.

Description

Technical Field

[0001] The invention relates to the field of thin-walled casing parts of aircraft engines, and in particular to a hydraulic automatic pressing and expanding clamp for machining thin-walled casings. Background Art

[0002] The casing, known as the skeleton of an aircraft engine, is the main load-bearing component of the engine. The structure of the parts is complex and they are typical thin-walled and weakly rigid parts. The design requirements for the dimensional accuracy and geometric tolerance accuracy of the parts are high and they must be processed using special fixtures. The original process used traditional mechanical clamping fixtures, and the main problems were:

[0003] 1) The installation, alignment and disassembly of fixtures and parts take a long time;

[0004] 2) Poor clamping stability and consistency;

[0005] 3) The clamping method is unreasonable, and the clamping force is inconsistent during clamping, causing deformation of the thin-walled casing;

[0006] 4) The fixture has poor versatility and requires frequent loading and unloading. Summary of the invention

[0007] The purpose of the present invention is that with the construction of automated production lines and lean units for aero-engine parts, it is urgent to realize automatic clamping and rapid replacement of casing parts and fixtures to improve the processing efficiency of thin-walled casing parts. By mastering and applying the zero-point positioning quick-change technology of fixtures for numerical control processing of casing parts, hydraulic control automatic pressing and expansion technology to solve the problem of unstable clamping quality of casing parts, realize rapid clamping of parts and fixtures, and improve production preparation efficiency, a hydraulic automatic pressing and expansion fixture for thin-walled casing processing is specially provided.

[0008] The present invention provides a hydraulic automatic pressing and expanding clamp for machining thin-walled casings, which is characterized by:

[0009] It consists of positioning components, 9 groups of hydraulic clamping mechanisms, hydraulic expansion mechanisms, pre-alignment mechanisms and zero-point positioning interfaces, etc. Its structural features are:

[0010] 1) The fixture adopts fixed stopper + three-jaw clamping mechanism for joint positioning. The fixed stopper is roughly positioned, and the hydraulically controlled three-jaw expansion mechanism is a high-precision self-centering mechanism with fine-tuned jaws. It completes centering, expansion and positioning, meeting the expansion accuracy requirements of on-site parts while being compatible with the roundness errors of parts, making it convenient to position and fine-tune some parts in poor condition;

[0011] 2) 9 hydraulic lever cylinders are used to clamp the workpiece to ensure the rigidity and stability of the parts clamping;

[0012] 3) It has a zero-point positioning interface, which can realize rapid positioning and clamping with the zero-point positioning workbench of the machine tool, and the repeated positioning accuracy is no more than 0.01mm;

[0013] 4) The fixture adopts a sealed structure, which facilitates chip and water removal while preventing cutting fluid and iron chips from entering the fixture;

[0014] 5) The fixture is highly flexible and can be used to suspend processing at any time for inspection or to change parts during processing;

[0015] 6) Pressure-maintaining hydraulic clamp design, no hydraulic pressure is required after clamping the parts;

[0016] 7) Design a detection ring to detect the automatic centering accuracy.

[0017] A hydraulic automatic pressing and expanding clamp for machining thin-walled casings, the hydraulic automatic pressing and expanding clamp for machining thin-walled casings,

[0018] The thin-walled casing of the present invention has a structure as follows Figure 1 The fixture involves a turning process, the axial positioning reference A of the part, the radial positioning reference B, and the clamping C.

[0019] like Figure 2 — Figure 4 , hydraulic automatic pressing and expanding clamp structure diagram, the hydraulic automatic pressing and expanding clamp for thin-walled casing processing includes five parts:

[0020] The first part is the base, which consists of a lower base 1 and an upper base 7, forming the skeleton of the fixture, with a built-in hydraulic oil circuit inside, and serves as the connection basis for other parts.

[0021] The second part is the positioning component, which is positioned by 9 end face positioning blocks 2 and a hydraulic three-jaw expansion mechanism 5. The 9 end face positioning blocks 2 position the end face A of the receiver and roughly position the inner hole B of the receiver. The hydraulically controlled three-jaw expansion mechanism 5 is a high-precision self-centering mechanism with fine-tuned jaws. It completes the centering expansion and automatically positions the inner hole, meeting the clamping accuracy requirements of the on-site parts while being compatible with the errors in the roundness of the parts, making it convenient to position and fine-tune some parts in poor condition.

[0022] The third part is the clamping assembly, which consists of 9 groups of clamping lever cylinder assemblies 3, which clamp the upper end surface C of the mounting edge of the casing. In the present invention, a connecting rod type clamping oil cylinder is selected because the two parameters of the hydraulic cylinder stroke and the jaw swing angle are basically in linear proportional relationship. By utilizing this feature, the jaw swing angle can be adjusted to make the fixture suitable for clamping workpieces of various types and sizes; when the jaw is in the terminal position, the jaw swing angular velocity is zero, so that the impact force on the workpiece when the jaw clamps the workpiece is zero, and no damage is caused to its surface; the jaw swing angle is 180°, and this position is the dead point position of the connecting rod mechanism, and the fixture has the most reliable self-locking function.

[0023] The fourth part is the pre-alignment mechanism, which consists of a pre-adjustment pressure plate assembly 4 and a process ring 8. The positioning size of the process ring 8 is the same as that of the receiver. Before the fixture is installed on the receiver for formal processing, the pre-alignment mechanism is used to align the fixture on the pre-adjustment table outside the machine, and then the receiver is installed for hydraulic compression and expansion. The pre-alignment mechanism can complete the installation and adjustment of the receiver outside the machine, reduce the machine time occupied by parts clamping, and greatly reduce the part process preparation time.

[0024] The fifth part is the zero-point positioning interface positioning system, which consists of 9 zero-point positioning joints, of which 1 is a zero-point cylindrical joint, 1 is a zero-point one-way joint, and the other 7 are zero-point fastening joints. The zero-point positioning interface positioning system matches the base seat with a zero-point locator on the machine tool to achieve rapid replacement of the fixture. If it is a casing milling or drilling process, the fixture needs to use an angle pin 10 to increase the angular positioning of the part.

[0025] The hydraulic automatic clamping part includes a pressure reducing valve 01, an accumulator 02, a sequence valve 03, a pressure gauge 04, a hydraulically controlled one-way valve 05, 9 clamping lever cylinder supports 06, and a hydraulic three-claw expansion cylinder support 07; wherein: the hydraulically controlled one-way valve 05, the accumulator 02, the pressure gauge 04, the pressure reducing valve 01, the sequence valve 03 and the 9 clamping lever cylinder supports 06 are connected in sequence, and the pressure reducing valve 01 is connected to the hydraulic three-claw expansion cylinder support 07.

[0026] Figure 5 Hydraulic components structure diagram, Figure 6 It is a hydraulic principle diagram;

[0027] Since some machine tools do not have hydraulic oil circuits, the hydraulic automatic clamping and expansion clamp must have a pressure-maintaining function. The present invention uses a pressure-maintaining circuit of a hydraulically controlled one-way valve with good sealing performance. However, due to internal leakage of hydraulically controlled one-way valve components, the circuit pressure-maintaining time is short and the pressure is not very stable. Therefore, in the present invention, a pressure-maintaining circuit using a hydraulic one-way valve and an accumulator in combination is selected, that is, an accumulator is set between the hydraulic one-way valve and the rodless chamber of the hydraulic cylinder to compensate for the leakage of the hydraulic one-way valve, thereby solving the problem of failure of the hydraulic one-way valve to maintain pressure.

[0028] Before machining the thin-walled casing, install the hydraulic automatic clamping and expansion fixture on the pre-adjustment table, align the fixture first, then install the process ring 8 on the fixture, use 3 sets of pre-adjustment pressure plate assemblies 4 to clamp the installation edge of the process ring, align the process ring, and then install the casing part 11 to be processed, connect the hydraulic station, use hydraulic oil to expand the parts first, and then use the lever cylinder to clamp the installation edge of the casing to complete the external clamping of the casing, disconnect the fixture from the hydraulic station and enter the pressure holding mode. When the formal machining is to be carried out, install the assembled casing fixture on the zero-point quick-change base of the machine tool, ventilate and quickly clamp the fixture, and then you can start machining the parts.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The hydraulic automatic clamping and expansion clamp for processing thin-walled casings of the present invention realizes the rapid clamping of the clamp and parts, shortens the time for clamping and aligning parts, realizes the high flexibility of the clamp, and can pause processing for inspection or change parts at any time. The process preparation time is shortened by more than 40%, and the rigidity of the workpiece is improved by the hydraulic clamping and expansion mechanism, which can increase the cutting amount and improve production efficiency. The present invention has good application prospects and has reference significance for the CNC processing of similar thin-walled annular parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0032] Figure 1 Structural diagram of thin-walled casing parts;

[0033] Figure 2 Three-dimensional diagram of the fixture;

[0034] Figure 3 Top view of hydraulic automatic clamping and expansion fixture;

[0035] Figure 4 Cross-sectional view of hydraulic automatic clamping and expansion fixture;

[0036] Figure 5 Hydraulic component structure diagram;

[0037] Figure 6 Hydraulic schematic diagram;

[0038] Figure 7 Cross-sectional view of the fixture for assembling thin-walled receivers;

[0039] In the figure, 1. lower base 2. end face positioning block 3. clamping lever cylinder assembly 4. pre-adjusting pressure plate assembly 5. hydraulic three-jaw expansion assembly 6. zero point quick change assembly 7. upper base 8. process ring 9. hydraulic assembly 10. angle pin 11. thin-walled casing; 01 pressure reducing valve, 02 accumulator, 03 sequence valve, 04 pressure gauge, 05 hydraulically controlled one-way valve, 06 clamping lever cylinder support, 07 hydraulic three-jaw expansion cylinder support. DETAILED DESCRIPTION

[0040] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0041] A hydraulic automatic pressing and expanding clamp for machining thin-walled casings, the hydraulic automatic pressing and expanding clamp for machining thin-walled casings,

[0042] The thin-walled casing of the present invention has a structure as follows Figure 1 The fixture involves a turning process, the axial positioning reference A of the part, the radial positioning reference B, and the clamping C.

[0043] like Figure 2 — Figure 4 , hydraulic automatic pressing and expanding clamp structure diagram, the hydraulic automatic pressing and expanding clamp for thin-walled casing processing includes five parts:

[0044] The first part is the base, which consists of a lower base 1 and an upper base 7, forming the skeleton of the fixture, with a built-in hydraulic oil circuit inside, and serves as the connection basis for other parts.

[0045] The second part is the positioning component, which is positioned by 9 end face positioning blocks 2 and a hydraulic three-jaw expansion mechanism 5. The 9 end face positioning blocks 2 position the end face A of the receiver and roughly position the inner hole B of the receiver. The hydraulically controlled three-jaw expansion mechanism 5 is a high-precision self-centering mechanism with fine-tuned jaws. It completes the centering expansion and automatically positions the inner hole, meeting the clamping accuracy requirements of the on-site parts while being compatible with the errors in the roundness of the parts, making it convenient to position and fine-tune some parts in poor condition.

[0046] The third part is the clamping assembly, which consists of 9 groups of clamping lever cylinder assemblies 3, which clamp the upper end surface C of the mounting edge of the casing. In the present invention, a connecting rod type clamping oil cylinder is selected because the two parameters of the hydraulic cylinder stroke and the jaw swing angle are basically in linear proportional relationship. By utilizing this feature, the jaw swing angle can be adjusted to make the fixture suitable for clamping workpieces of various types and sizes; when the jaw is in the terminal position, the jaw swing angular velocity is zero, so that the impact force on the workpiece when the jaw clamps the workpiece is zero, and no damage is caused to its surface; the jaw swing angle is 180°, and this position is the dead point position of the connecting rod mechanism, and the fixture has the most reliable self-locking function.

[0047] The fourth part is the pre-alignment mechanism, which consists of a pre-adjustment pressure plate assembly 4 and a process ring 8. The positioning size of the process ring 8 is the same as that of the receiver. Before the fixture is installed on the receiver for formal processing, the pre-alignment mechanism is used to align the fixture on the pre-adjustment table outside the machine, and then the receiver is installed for hydraulic compression and expansion. The pre-alignment mechanism can complete the installation and adjustment of the receiver outside the machine, reduce the machine time occupied by parts clamping, and greatly reduce the part process preparation time.

[0048] The fifth part is the zero-point positioning interface positioning system, which consists of 9 zero-point positioning joints, of which 1 is a zero-point cylindrical joint, 1 is a zero-point one-way joint, and the other 7 are zero-point fastening joints. The zero-point positioning interface positioning system matches the base seat with a zero-point locator on the machine tool to achieve rapid replacement of the fixture. If it is a casing milling or drilling process, the fixture needs to use an angle pin 10 to increase the angular positioning of the part.

[0049] The hydraulic automatic clamping part includes a pressure reducing valve 01, an accumulator 02, a sequence valve 03, a pressure gauge 04, a hydraulically controlled one-way valve 05, 9 clamping lever cylinder supports 06, and a hydraulic three-claw expansion cylinder support 07; wherein: the hydraulically controlled one-way valve 05, the accumulator 02, the pressure gauge 04, the pressure reducing valve 01, the sequence valve 03 and the 9 clamping lever cylinder supports 06 are connected in sequence, and the pressure reducing valve 01 is connected to the hydraulic three-claw expansion cylinder support 07.

[0050] Figure 5 Hydraulic components structure diagram, Figure 6 It is a hydraulic principle diagram;

[0051] Since some machine tools do not have hydraulic oil circuits, the hydraulic automatic clamping and expansion clamp must have a pressure-maintaining function. The present invention uses a pressure-maintaining circuit of a hydraulically controlled one-way valve with good sealing performance. However, due to internal leakage of hydraulically controlled one-way valve components, the circuit pressure-maintaining time is short and the pressure is not very stable. Therefore, in the present invention, a pressure-maintaining circuit using a hydraulic one-way valve and an accumulator in combination is selected, that is, an accumulator is set between the hydraulic one-way valve and the rodless chamber of the hydraulic cylinder to compensate for the leakage of the hydraulic one-way valve, thereby solving the problem of failure of the hydraulic one-way valve to maintain pressure.

[0052] Before machining the thin-walled casing, install the hydraulic automatic clamping and expansion fixture on the pre-adjustment table, align the fixture first, then install the process ring 8 on the fixture, use 3 sets of pre-adjustment pressure plate assemblies 4 to clamp the installation edge of the process ring, align the process ring, and then install the casing part 11 to be processed, connect the hydraulic station, use hydraulic oil to expand the parts first, and then use the lever cylinder to clamp the installation edge of the casing to complete the external clamping of the casing, disconnect the fixture from the hydraulic station and enter the pressure holding mode. When the formal machining is to be carried out, install the assembled casing fixture on the zero-point quick-change base of the machine tool, ventilate and quickly clamp the fixture, and then you can start machining the parts.

[0053] Matters not covered by the present invention are known technologies.

[0054] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic automatic pressing and expanding clamp for processing thin-walled casings, characterized in that: The hydraulic automatic pressing and expanding clamp for processing thin-walled casings comprises five parts: The first part is the base, which consists of a lower base 1 and an upper base 7, forming the framework of the fixture, with a built-in hydraulic oil circuit inside, and serves as the connection basis for other parts; The second part is the positioning component, which is positioned by 9 end face positioning blocks 2 and a hydraulic three-claw expansion mechanism 5. The 9 end face positioning blocks 2 position the end face A of the casing and roughly position the inner hole B of the casing. The hydraulically controlled three-claw expansion mechanism 5 is a high-precision self-centering mechanism with fine-tunable jaws. It completes centering expansion and automatically positions the inner hole, meeting the clamping accuracy requirements of the parts on site while being compatible with the roundness errors of the parts, making it convenient to position and fine-tune some parts in poor condition. The third part is a clamping assembly, which is composed of 9 groups of clamping lever cylinder assemblies 3, and the upper end surface C of the mounting side of the clamping casing is selected in the present invention, because the two parameters of the hydraulic cylinder stroke and the jaw swing angle are basically in a linear proportional relationship. By using this feature, the clamp can be used to clamp workpieces of various types and sizes by adjusting the jaw swing angle; when the jaw is at the end position, the jaw swing angular velocity is zero, so that the impact force on the workpiece when the jaw clamps the workpiece is zero, and no damage is caused to its surface; the jaw swing angle is 180°, and this position is the dead point position of the connecting rod mechanism, and the clamp has the most reliable self-locking function; The fourth part is the pre-alignment mechanism, which is composed of a pre-adjustment pressure plate assembly 4 and a process ring 8. The positioning size of the process ring 8 is the same as that of the casing. Before the fixture is installed on the casing to be formally processed, the fixture is first aligned on the pre-adjustment table outside the machine using the pre-alignment mechanism, and then the casing is installed for hydraulic compression and expansion. The pre-alignment mechanism can complete the installation and adjustment of the casing outside the machine, reduce the machine time occupied by the parts clamping, and greatly reduce the part process preparation time; The fifth part is the zero-point positioning interface positioning system, which consists of 9 zero-point positioning joints, of which 1 is a zero-point cylindrical joint, 1 is a zero-point one-way joint, and the other 7 are zero-point fastening joints. The zero-point positioning interface positioning system matches the base seat with a zero-point locator on the machine tool to achieve rapid replacement of the fixture; if it is a casing milling or drilling process, the fixture needs to use an angular pin 10 to increase the angular positioning of the part.

2. The hydraulic automatic pressing and expanding clamp for machining thin-walled casing according to claim 1 is characterized in that: The hydraulic automatic clamping part includes a pressure reducing valve, an accumulator, a sequence valve, a pressure gauge, a hydraulically controlled one-way valve, 9 clamping lever cylinder supports, and a hydraulic three-claw expansion cylinder support; wherein: the hydraulically controlled one-way valve, the accumulator, the pressure gauge, the pressure reducing valve, the sequence valve and the 9 clamping lever cylinder supports are connected in sequence, and the pressure reducing valve is connected to the hydraulic three-claw expansion cylinder support.

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