An automatic clamping fixture with a locking seat guide sleeve and its processing method

Abstract

This invention discloses an automatic clamping fixture with a locking seat guide sleeve and a machining method. It includes a fixture base plate, on which a follower indexing plate and a servo indexing plate are mounted. A fixture connecting base is installed between the follower indexing plate and the servo indexing plate. The fixture connecting base has a circular through hole, and a three-jaw hydraulic chuck is fixed in the circular through hole. A workpiece positioning flange is connected to the upper side of the three-jaw hydraulic chuck. A fixed axial positioning block and a lateral positioning cylinder are connected to the upper side of the workpiece positioning flange, with the lateral positioning cylinder and the fixed axial positioning block arranged opposite each other. This invention utilizes the automatic centering principle of the three-jaw chuck for clamping, and in conjunction with the axial positioning cylinder, achieves automatic alignment and clamping, performing all non-turning operations in a single clamping operation. It offers high changeover efficiency, simple maintenance, and is applicable to the machining of various workpieces, effectively reducing labor intensity.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder machining technology, specifically an automatic clamping fixture with a locking seat guide sleeve and a machining method. Background Technology

[0002] Guide sleeve: The guide sleeve of the hydraulic cylinder serves to support and maintain the coaxiality of the piston rod and cylinder barrel. During the extension of the piston rod, it ensures contact between the surfaces of the hydraulic cylinder and cylinder barrel. The longer the stroke of the hydraulic cylinder, the longer the guide sleeve. It also provides support for the oil seal at the cylinder port.

[0003] The guide sleeve is a core component inside the hydraulic cylinder. It ensures that the piston rod moves linearly inside the cylinder barrel. It has sealing and support grooves inside to support the seal and ensure the sealing performance of the hydraulic cylinder. The coaxiality, surface roughness and other key dimensions of the guide sleeve directly affect the performance of the hydraulic cylinder.

[0004] For guide sleeves with flanges and lock seats, the machining features include internal and external turning, internal and external groove turning, flange drilling, valve seat milling, drilling, tapping, and chamfering. Conventional machining uses a turning center for turning, or flange drilling and milling, followed by valve seat milling, drilling, and tapping using milling equipment, and finally manual deburring. Manual alignment is required during milling. This clamping method suffers from low efficiency in flange drilling due to the power limitations of the turning center, significant difficulty in machining some fine holes, and high tool costs. Furthermore, manual deburring is necessary, leading to high labor intensity. Multiple clamping operations affect machining accuracy, and automated production is either not feasible or only minimally automated, requiring manual handling of some processes.

[0005] Chinese patent CN215698284U discloses an indexing machining device for one-time forming of hydraulic cylinder guide sleeves. The device includes a guide sleeve fixture mounted on a CNC indexing plate, one side of which is hinged to a horizontal machining center. The CNC indexing plate has a flipping mechanism and a rotating mechanism. The flipping and rotating mechanisms each include a servo motor and a transmission mechanism, respectively. The CNC indexing plate includes a gear clutch disc; the transmission mechanism includes a worm gear assembly; and the guide sleeve fixture includes a hydraulic locking device. This device is used for five-axis flipping and linkage machining of hydraulic support cylinder guide sleeves on three-axis and four-axis horizontal machining centers. Existing equipment requires additional tooling to complete the one-time machining of the cylinder bottom and guide sleeve parts.

[0006] The disadvantages of the above-mentioned prior art are:

[0007] (1) Its clamping device is a hydraulic locking device. This device cannot achieve self-centering clamping of shaft parts, and the clamping accuracy is low, the operation is cumbersome, the reliability is low, and the problem of iron filings entanglement is easy to occur in automation.

[0008] (2) The tooling is installed on the CNC indexing plate, one side of which is hinged to the horizontal machining center. The CNC indexing plate is equipped with a flipping mechanism and a rotating mechanism. It can be determined that the tooling has a limited reversal angle and cannot achieve machining at the same angle with the bottom surface facing up.

[0009] (3) The tooling is complex to implement and cannot be automatically clamped by a robot. The tooling is only suitable for guide sleeves of columns and hydraulic cylinders of jacks. For guide sleeves with flanges and lock seats, the tooling cannot achieve automatic positioning and clamping functions, and the applicable processing procedures are limited. Summary of the Invention

[0010] To overcome the shortcomings of the prior art, this invention provides an automatic clamping fixture with a locking seat guide sleeve and a machining method thereof. This clamping fixture is applicable to machining processes such as drilling, milling, tapping, and chamfering with a locking seat guide sleeve, and can realize centralized machining of processes other than turning internal and external circles and grooves.

[0011] This invention is achieved through the following technical solution: an automatic clamping fixture with a locking seat guide sleeve, comprising a fixture base plate, on which a follower indexing plate and a servo indexing plate are mounted, and a fixture connecting base is installed between the follower indexing plate and the servo indexing plate; the fixture connecting base has a circular through hole, and a three-jaw hydraulic chuck is fixed in the circular through hole of the fixture connecting base, and a workpiece positioning flange is connected to the upper side of the three-jaw hydraulic chuck; a fixed axial positioning block and a lateral positioning cylinder are connected to the upper side of the workpiece positioning flange, and the lateral positioning cylinder and the fixed axial positioning block are arranged opposite each other.

[0012] Furthermore, the circular through holes of the three-jaw hydraulic chuck, the workpiece positioning flange, and the tooling connecting base are arranged coaxially; the three-jaw hydraulic chuck has a flange around its periphery, and the flange is fixedly connected to the inner shoulder of the circular through hole of the tooling connecting base by screws; a threaded hole is opened on the upper side of the three-jaw hydraulic chuck, and the workpiece positioning flange is connected to the threaded hole on the upper side of the three-jaw hydraulic chuck by screws.

[0013] The workpiece positioning flange is used to place the guide sleeve to be processed; the fixed axial positioning block and the lateral positioning cylinder are respectively placed on both sides of the locking seat of the guide sleeve to be processed. During operation, the fixed axial positioning block and the lateral positioning cylinder abut against both sides of the locking seat of the guide sleeve to be processed.

[0014] The surface of the three-jaw hydraulic chuck is provided with a relief groove that mates with the locking seat of the guide sleeve to be processed; the side of the workpiece positioning flange is provided with a relief through groove that mates with the locking seat of the guide sleeve to be processed; the relief through groove, the relief groove and the locking seat of the guide sleeve to be processed are axially opposite each other.

[0015] The three-jaw hydraulic chuck includes a chuck base and a chuck moving block that is radially slidably mounted on the chuck base; a replaceable jaw is fixed to the chuck moving block by screws; the inner end face of the replaceable jaw is an arc-shaped surface, and an avoidance hole is provided at the inner end of the replaceable jaw.

[0016] The lateral positioning cylinder includes a cylinder body; the cylinder body has parallel sliding holes and sliding tracks; a piston is slidably installed in the sliding holes of the cylinder body, and a sealing ring is installed on the circumferential surface of the piston; a side top block is slidably installed in the sliding tracks of the cylinder body; a screw plug is fixed at the bottom of the sliding holes of the cylinder body, and the space between the screw plug and the piston is an oil cavity; the end of the piston away from the oil cavity is a spring cavity, and a spring is installed in the spring cavity;

[0017] A connecting elongated hole is provided between the cylinder slide hole and the slide channel, and a connecting pin passes through the connecting elongated hole. The two ends of the connecting pin are respectively connected to the piston and the side top block.

[0018] The tooling connecting base is fixedly connected to the corresponding side of the follow-up indexing plate and servo indexing plate at both ends by an L-shaped connecting plate.

[0019] A method for processing a guide sleeve with a locking seat.

[0020] The guide sleeve to be processed is placed on the workpiece positioning flange by a robot or manually. Then, the lateral positioning cylinder moves to the left to tighten the locking seat side of the guide sleeve to be processed for angle positioning. Then, the three-jaw hydraulic chuck extends to clamp the guide sleeve to be processed.

[0021] The servo indexing plate rotates to control the top of the guide sleeve to face upwards; the flange surface of the guide sleeve to be processed is drilled and milled.

[0022] The servo indexing plate rotates to control the end face of the guide sleeve lock seat to face upward, and performs milling, drilling, tapping and chamfering processes on the lock seat surface;

[0023] The servo indexing plate rotates, controlling the bottom end of the guide sleeve to face upwards, and performs the bottom chamfering process.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] (1) The three-jaw chuck is used for automatic clamping, and the axial positioning cylinder is used to realize automatic alignment and clamping. The operation is simple and the clamping accuracy is high. All non-turning processes are processed in one clamping, which truly realizes one-clamping processing and effectively ensures the relative positional relationship after processing.

[0026] (2) The tooling can be rotated at any angle and can be used to process the product by using the three-axis machining center. This effectively reduces the product’s dependence on equipment. Moreover, the tooling can be used to process all processes except turning. Only one CNC lathe and one three-axis vertical machining center are needed to process the product.

[0027] (3) The tooling can be changed by simply replacing the workpiece positioning flange and the replaceable jaws, without any other operations. The tooling has high efficiency, simple maintenance, and can be used for processing a variety of workpieces. The tooling has a high degree of automation, and can use a robotic arm to load and unload workpieces, achieving fully automated operation. It can also be used to perform deburring, effectively reducing labor intensity. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the present invention;

[0029] Figure 2 This is a schematic diagram of a hydraulic three-jaw chuck structure;

[0030] Figure 3 This is a schematic diagram of the lateral positioning cylinder structure;

[0031] Figure 4 This is a schematic diagram of the flange face machining of the guide sleeve to be machined;

[0032] Figure 5 This is a schematic diagram of the locking seat machining process for the guide sleeve to be machined;

[0033] Figure 6 This is a schematic diagram of the bottom side machining of the guide sleeve to be machined.

[0034] In the diagram: 1. Follow-up indexing plate; 2. L-shaped connecting side plate; 3. Workpiece positioning flange; 3-1. Clearance groove; 4. Guide sleeve to be processed; 5. Handle; 6. Lateral positioning cylinder; 6-1. Side top block; 6-2. Spring; 6-3. Cylinder body; 6-4. Piston; 6-5. Sealing ring; 6-6. Screw plug; 6-7. Connecting elongated hole; 6-8. Connecting pin; 7. Machine tool worktable; 8. Servo indexing plate; 9. Tooling base plate; 10. Tooling connecting base; 11. Hydraulic three-jaw chuck; 11-1. Clearance groove; 11-2. Chuck base; 11-3. Chuck moving block; 11-4. Replaceable jaws; 11-5. Clearance hole; 12. Fixed axial positioning block. Detailed Implementation

[0035] 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, and 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.

[0036] Example 1

[0037] like Figure 1 As shown, an automatic clamping fixture with a locking seat guide sleeve is provided. The fixture base plate 9 is connected to the machine tool worktable 7 via a T-nut. The follower indexing plate 1 and the servo indexing plate 8 are connected to the fixture base plate 9 via screws. The two ends of the fixture connecting base 10 are respectively fixedly connected to the follower indexing plate 1 and the servo indexing plate 8 on the corresponding sides via an L-shaped connecting plate 2.

[0038] The tooling connecting base 10 has a circular through hole at its center. A three-jaw hydraulic chuck 11 is fixed in the circular through hole of the tooling connecting base 10. A workpiece positioning flange 3 is connected to the upper side of the three-jaw hydraulic chuck 11. The three-jaw hydraulic chuck 11, the workpiece positioning flange 3, and the circular through hole of the tooling connecting base 10 are arranged coaxially. The workpiece positioning flange 3 is used to place the guide sleeve 4 to be processed. A fixed axial positioning block 12 and a lateral positioning cylinder 6 are connected to the upper side of the workpiece positioning flange 3 by connecting screws. The lateral positioning cylinder 6 and the fixed axial positioning block 12 are arranged opposite to each other.

[0039] Combination Figure 1 and Figure 2 As shown, the three-jaw hydraulic chuck 11 has a flange around its periphery, which is fixedly connected to the inner shoulder of the circular through hole of the tooling connection base 10 by screws. The three-jaw hydraulic chuck 11 includes a chuck base 11-2 and a chuck moving block 11-3 that is radially slidably mounted on the chuck base 11-2. In this embodiment, replaceable jaws 11-4 are fixed to the chuck moving block 11-3 by screws. Different replaceable jaws 11-4 can be used depending on the different guide sleeves 4 to be processed. The inner end face of the replaceable jaw 11-4 is an arc-shaped surface, used to cooperate in pressing the guide sleeve 4 to be processed. The inner end of the replaceable jaw 11-4 is provided with a clearance hole 11-5 to solve the interference problem during drilling.

[0040] The upper side of the three-jaw hydraulic chuck 11 has threaded holes, and the workpiece positioning flange 3 is connected to the threaded holes on the upper side of the three-jaw hydraulic chuck 11 by screws. Different diameter guide sleeves 4 can be accommodated by replacing different workpiece positioning flanges 3. There are two sets of handles 5 on the workpiece positioning flange 3, and the workpiece positioning flange 3 can be quickly replaced by using the handles 5. The surface of the three-jaw hydraulic chuck 11 has a milling cutter clearance groove 11-1 that is milled to fit the lock seat of the guide sleeve 4; the side of the workpiece positioning flange 3 has a milling cutter clearance through groove 3-1 that is milled to fit the lock seat of the guide sleeve 4; the clearance through groove 3-1, the clearance groove 11-1 and the lock seat of the guide sleeve 4 are axially opposite.

[0041] Combination Figure 1 and Figure 3As shown, the fixed axial positioning block 12 and the lateral positioning cylinder 6 are respectively placed on both sides of the lock seat of the guide sleeve 4 to be processed. During operation, the fixed axial positioning block 12 and the lateral positioning cylinder 6 abut against both sides of the lock seat of the guide sleeve 4 to be processed.

[0042] The lateral positioning cylinder 6 includes a cylinder body 6-3, in which parallel sliding holes and slideways are formed. A piston 6-4 is slidably mounted in the sliding hole of the cylinder body 6-3, and a sealing ring 6-5 is mounted on the circumferential surface of the piston 6-4. A side top block 6-1 is slidably mounted in the slideway of the cylinder body 6-3. A screw plug 6-6 is fixed to the bottom of the sliding hole of the cylinder body 6-3, and an oil cavity is formed between the screw plug 6-6 and the piston 6-4. An oil port communicating with the oil cavity is provided on the cylinder body 6-3. The end of the piston 6-4 away from the oil cavity is a spring cavity, in which a spring 6-2 is installed. The spring 6-2 is used to control the piston 6-4 to return to its original position. A connecting elongated hole 6-7 is formed between the sliding hole and the slideway of the cylinder body 6-3. A connecting pin 6-8 passes through the connecting elongated hole 6-7, and both ends of the connecting pin 6-8 are connected to the piston 6-4 and the side top block 6-1, respectively. When there is no hydraulic oil, piston 6-4 is located on the right side of cylinder 6-3 under the action of spring 6-2 and is in the reset state. When hydraulic oil is added to the oil chamber on the right side of piston 6-4, piston 6-4 moves to the left, driving side top block 1 to move to the left, realizing the clamping action.

[0043] Example 2

[0044] A method for processing a guide sleeve with a locking seat, using the automatic clamping fixture with a locking seat guide sleeve in the above embodiment 1;

[0045] The guide sleeve 4 to be processed is placed on the workpiece positioning flange 3 by a robot or manually. Then the lateral positioning cylinder 6 moves to the left to press the locking side of the guide sleeve 4 to be processed for angle positioning. Then the three-jaw hydraulic chuck 11 extends to clamp the guide sleeve 4 to be processed.

[0046] The servo indexing plate 8 rotates to control the top of the guide sleeve 4 to be processed to face upwards; and performs processing operations such as drilling and milling on the flange surface of the guide sleeve 4 to be processed.

[0047] The servo indexing plate 8 rotates to control the end face of the lock seat of the guide sleeve 4 to face upward, and performs processing operations such as milling, drilling, tapping, and chamfering of the lock seat surface;

[0048] The servo indexing plate 8 rotates, controlling the bottom end of the guide sleeve 4 to face upwards, and performs the bottom chamfering process.

[0049] This embodiment employs a three-jaw chuck principle to achieve automatic clamping of the machining center, unlike conventional methods that use mandrel positioning or indexing plates for clamping. This embodiment offers simpler operation and easier model changeover. The lateral positioning cylinder utilizes a piston to laterally drive the end-face positioning block, with the sealing function integrated into the piston. An internal spring enables reset, reducing the number of oil outlets and allowing for single-sided oil inlet and outlet, effectively simplifying the lateral positioning cylinder structure. A servo indexing plate is used for rotary drive, with another indexing plate as the driven axis, enabling a standard three-axis vertical machining center to perform oscillating machining. This provides high repeatability and positioning accuracy, with a simple structure and automatic control. The workpiece positioning device is fabricated as a workpiece positioning flange with positioning pin holes at the bottom, allowing for rapid model changeover positioning and reducing changeover time. The entire device can be replaced for modular replacement. This embodiment is designed for guide sleeves with locking seats, enabling automatic positioning and clamping with a simple and highly accurate clamping method.

[0050] This embodiment primarily targets machining processes such as drilling, milling, tapping, and chamfering of guide sleeves with locking seats, enabling centralized machining of processes other than turning internal and external diameters and grooves. Using this fixture, only a CNC lathe is needed for turning, eliminating the need for a high-performance turning center, thus reducing equipment costs. Utilizing the automatic positioning and clamping principle of a three-jaw chuck, automatic clamping and positioning on the machining center is achieved, eliminating the need for manual workpiece calibration and enabling multiple processes to be processed on a single machine.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automatic clamping fixture with a locking seat guide sleeve, comprising a fixture base plate (9), on which a follower indexing plate (1) and a servo indexing plate (8) are mounted, and a fixture connecting base (10) is mounted between the follower indexing plate (1) and the servo indexing plate (8). Its characteristics are: The tooling connection base (10) has a circular through hole, and a three-jaw hydraulic chuck (11) is fixed in the circular through hole of the tooling connection base (10). A workpiece positioning flange (3) is connected to the upper side of the three-jaw hydraulic chuck (11). A fixed axial positioning block (12) and a lateral positioning cylinder (6) are connected to the upper side of the workpiece positioning flange (3). The lateral positioning cylinder (6) is arranged opposite to the fixed axial positioning block (12). The workpiece positioning flange (3) is used to place the guide sleeve (4) to be processed; the fixed axial positioning block (12) and the lateral positioning cylinder (6) are respectively placed on both sides of the lock seat of the guide sleeve (4) to be processed. When working, the fixed axial positioning block (12) and the lateral positioning cylinder (6) abut against both sides of the lock seat of the guide sleeve (4) to be processed. The surface of the three-jaw hydraulic chuck (11) is provided with a clearance groove (11-1) that cooperates with the locking seat of the guide sleeve (4) to be processed; the side of the workpiece positioning flange (3) is provided with a clearance through groove (3-1) that cooperates with the locking seat of the guide sleeve (4) to be processed; the clearance through groove (3-1), the clearance groove (11-1) and the locking seat of the guide sleeve (4) to be processed are axially opposite to each other; The lateral positioning cylinder (6) includes a cylinder body (6-3); parallel sliding holes and slideways are provided in the cylinder body (6-3); a piston (6-4) is slidably installed in the sliding hole of the cylinder body (6-3), and a sealing ring (6-5) is installed on the circumferential surface of the piston (6-4); a side top block (6-1) is slidably installed in the slideway of the cylinder body (6-3); a screw plug (6-6) is fixed at the bottom of the sliding hole of the cylinder body (6-3), and an oil cavity is formed between the screw plug (6-6) and the piston (6-4); the end of the piston (6-4) away from the oil cavity is a spring cavity, and a spring (6-2) is installed in the spring cavity. A connecting elongated hole (6-7) is provided between the sliding hole and the slide rail of the cylinder body (6-3). A connecting pin (6-8) is provided through the connecting elongated hole (6-7). The two ends of the connecting pin (6-8) are connected to the piston (6-4) and the side top block (6-1) respectively.

2. The automatic clamping fixture with a locking seat guide sleeve according to claim 1, characterized in that: The circular through holes of the three-jaw hydraulic chuck (11), the workpiece positioning flange (3) and the tooling connection base (10) are arranged coaxially; the three-jaw hydraulic chuck (11) has a flange around its periphery, and the flange is fixedly connected to the inner shoulder of the circular through hole of the tooling connection base (10) by screws; the upper side of the three-jaw hydraulic chuck (11) is provided with a threaded hole, and the workpiece positioning flange (3) is connected to the threaded hole on the upper side of the three-jaw hydraulic chuck (11) by screws.

3. The automatic clamping fixture with a locking seat guide sleeve according to claim 1, characterized in that: The three-jaw hydraulic chuck (11) includes a chuck base (11-2) and a chuck moving block (11-3) that is radially slidably mounted on the chuck base (11-2); a replaceable jaw (11-4) is fixed on the chuck moving block (11-3) by screws; the inner end face of the replaceable jaw (11-4) is an arc-shaped surface, and an avoidance hole (11-5) is opened at the inner end of the replaceable jaw (11-4).

4. The automatic clamping fixture with a locking seat guide sleeve according to claim 1, characterized in that: The tooling connection base (10) is fixedly connected at both ends to the corresponding side follow-up indexing plate (1) and servo indexing plate (8) through an L-shaped connecting plate (2).

5. A method for processing a guide sleeve with a locking seat, using an automatic clamping fixture with a locking seat as described in any one of claims 1 to 4, characterized in that: The guide sleeve (4) to be processed is placed on the workpiece positioning flange (3) by a robot or manually. Then the lateral positioning cylinder (6) moves to the left to press the locking side of the guide sleeve (4) to be processed for angle positioning. Then the three-jaw hydraulic chuck (11) extends to clamp the guide sleeve (4) to be processed. The servo indexing plate (8) rotates to control the top of the guide sleeve (4) to be processed to face upward; and performs the flange surface drilling and milling process of the guide sleeve (4) to be processed. The servo indexing plate (8) rotates to control the end face of the lock seat of the guide sleeve (4) to face upward, and perform the lock seat surface milling, drilling, tapping and chamfering processes. The servo indexing plate (8) rotates, controlling the bottom end of the guide sleeve (4) to face upwards, and performs the bottom chamfering process.

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