A drilling device for oil cylinder production

Abstract

The application provides a drilling device for oil cylinder production and belongs to the technical field of machining equipment. The device comprises a bed body, a main shaft drilling system and a workpiece clamping and positioning system. The main shaft drilling system has multiple drill bits for synchronously drilling multiple oil holes on the cylinder barrel of the oil cylinder under one-time clamping. The workpiece clamping and positioning system comprises a self-centering positioning seat, a swing pressing mechanism and an axially adjustable stopper. The self-centering positioning seat and the swing pressing mechanism are arranged along the longitudinal direction of the workbench surface of the bed body at intervals. The axially adjustable stopper is arranged at the longitudinal end of the workbench surface. The application combines the synchronous multi-hole drilling function with the composite positioning and clamping system comprising the self-centering, swing pressing and axially adjustable stopper. The machining of all oil holes is completed under one-time clamping. The cumulative error of multiple clamping is completely eliminated. The relative position accuracy of the oil holes and the batch production efficiency are simultaneously improved. The device has high precision, high efficiency and high flexibility.

Description

Technical Field

[0001] This invention relates to the field of fish slaughtering equipment technology, specifically to a drilling device for hydraulic cylinder production. Background Technology

[0002] As a core actuator in coal mining machinery and engineering hydraulic equipment, the hydraulic cylinder requires several oil holes machined on its cylinder barrel to install oil nozzles and connectors. The relative positional accuracy of these oil holes directly affects the assembly performance and sealing reliability of the hydraulic cylinder.

[0003] Currently, the drilling of oil holes in hydraulic cylinder barrels commonly employs radial drilling machines in conjunction with manual marking and positioning, requiring multiple workpiece clamping and drilling of each hole sequentially. This machining method suffers from repeated clamping, leading to repeated changes in the positioning datum and the continuous accumulation of clamping errors. This makes it difficult to guarantee the relative positional accuracy between multiple oil holes on the same cylinder barrel, and out-of-tolerance hole positions can easily cause difficulties in hydraulic cylinder assembly. Simultaneously, the sequential drilling method results in excessively long cycle times for single-piece machining. In mass production, the drilling process becomes a bottleneck for the entire production line, severely restricting capacity. Both of these problems are essentially caused by the multiple clamping and serial single-hole machining mode, and they exacerbate each other. Simply increasing the parameters of a single drilling operation cannot simultaneously achieve both accuracy and efficiency.

[0004] Therefore, there is an urgent need to provide a device that can simultaneously complete the high-precision drilling of all oil holes on the cylinder barrel in a single clamping operation, so as to improve the mass production efficiency and finished product quality of hydraulic cylinders. Summary of the Invention

[0005] In view of this, the present invention provides a drilling device for hydraulic cylinder production, which solves the problems of poor oil hole position accuracy and low processing efficiency caused by multiple clamping and drilling hole by hole in traditional drilling devices.

[0006] To address the aforementioned technical problems, this invention provides a drilling device for hydraulic cylinder production, comprising a machine bed, and a spindle drilling system and a workpiece clamping and positioning system disposed on the machine bed. The spindle drilling system has multiple drill bits for simultaneously drilling multiple oil holes on the cylinder barrel in a single clamping operation. The workpiece clamping and positioning system includes a self-centering positioning seat, a swing-type clamping mechanism, and an axially adjustable stop. The self-centering positioning seat and the swing-type clamping mechanism are arranged longitudinally at intervals along the worktable surface of the machine bed, and the axially adjustable stop is disposed at the longitudinal end of the worktable surface.

[0007] In this technical solution, multiple drill bits are drilled simultaneously, and a composite clamping and positioning system that can provide radial self-centering, axial adjustable positioning and stable clamping is used to complete the machining of all oil holes in the cylinder barrel after one clamping. This fundamentally eliminates the reference change and error accumulation caused by multiple clamping, and at the same time greatly shortens the machining cycle.

[0008] The machine bed is integrally cast from HT250 gray cast iron, which has excellent vibration absorption and casting processability. The worktable surface is formed with a wear-resistant hardened layer through high-frequency induction hardening, with a hardness of HRC 45-55, to enhance the wear resistance of the table surface and maintain its accuracy for a long time.

[0009] The spindle drilling system includes a mechanism for synchronously rotating multiple drill bits. As a preferred implementation, this mechanism can be a multi-axis drilling mechanism, comprising a gearbox and multiple output spindles. The input end of the gearbox is detachably connected to the output shaft of the spindle box. The spatial arrangement of the multiple output spindles on the output side of the gearbox corresponds to the distribution of oil holes on the cylinder barrel to be processed. The gearbox ensures that each drill bit rotates synchronously and in phase. Each drill bit is clamped onto the output spindle via a spring collet, and the drill bits are carbide internally cooled twist drills. It is understood that the method by which the spindle drilling system synchronously drills multiple oil holes is not limited to the above-described mechanical linkage structure. Any mechanism capable of driving multiple drill bits to rotate synchronously along a predetermined layout, such as a multi-spindle motor synchronous control unit, falls within the scope of protection of this invention.

[0010] The self-centering locator is used for radial positioning of the cylinder and automatic centering of its axis. In a preferred embodiment, the self-centering locator includes a base and two opposing V-blocks, the V-shaped surfaces of the two V-blocks forming a positioning space to accommodate the cylinder. A wear-resistant liner made of polyurethane elastomer is bonded to each V-shaped surface via a hot vulcanization process, and the liner surface is machined with a textured anti-slip groove. This elastic liner increases the coefficient of friction with the outer surface of the cylinder, preventing workpiece deflection during drilling, and simultaneously uses the elastic deformation of polyurethane to compensate for the cylinder's outer diameter tolerance, avoiding scratches on the workpiece surface. It should be noted that the specific structure of the self-centering locator is not limited to the V-block form; any structure capable of automatically centering and positioning a cylindrical workpiece, such as a double-arc locating block or a toothed self-centering mechanism, can be used.

[0011] The swing-type clamping mechanism is used to apply radial clamping force to the cylinder, forming a stable clamping structure in conjunction with the self-centering positioning seat. Preferably, the swing-type clamping mechanism is a hydraulic swing-type clamping mechanism, which includes a hydraulic cylinder, a swing arm, and a clamping block. The hydraulic cylinder body is hinged to the worktable and its extension and retraction are controlled by a three-position four-way solenoid valve. One end of the swing arm is hinged to the piston rod of the hydraulic cylinder, and the middle part is rotatably mounted on the worktable via a hinge support. The clamping block is connected to the other end of the swing arm via a ball joint. The clamping surface of the clamping block is an arc-shaped surface adapted to the outer circular surface of the cylinder, and the surface of the arc-shaped surface is provided with a nitrile rubber elastic buffer pad. The ball joint enables the clamping block to have universal self-adaptive fitting capability, ensuring uniform contact between the arc-shaped surface and the cylinder and avoiding stress concentration. In addition, the power source of the swing-type clamping mechanism can also be other linear drive devices such as cylinders or electric push rods.

[0012] An axially adjustable stop block provides an axial positioning reference for cylinders of different lengths. It includes a stop block body, an adjusting screw, and a locking nut. The stop block body is slidably mounted on the longitudinal end of the worktable via a slide rail pair. The adjusting screw is axially limited on the worktable via a bearing seat and threadedly connected to the stop block body. The locking nut is screwed onto the adjusting screw to lock the axial position of the stop block body. The stop block body is made of 45# steel and has undergone quenching and tempering treatment.

[0013] As a further improvement, the device also includes a cooling chip removal system. This system includes a high-pressure internal cooling fluid supply device, which is connected to the internal coolant channel of the drill pipe, for directly delivering coolant to the drill bit's cutting area. Preferably, the cooling chip removal system also includes a negative pressure chip removal pipeline, which is connected to an annular chip collection hood surrounding the drilling area, for timely chip extraction. The high-pressure internal cooling fluid supply device includes a high-pressure pump station and a coolant filter. The high-pressure pump station is connected to a rotary joint via the coolant filter, and the rotary joint is connected to the internal coolant channel of the drill pipe, directly delivering high-pressure semi-synthetic cutting fluid to the nozzles at the drill bit's cutting edge, achieving precise cooling of the cutting area. The negative pressure chip removal pipeline is connected to the lower part of the annular chip collection hood, where a vortex negative pressure fan provides suction to promptly remove chips and waste fluid from the machining area.

[0014] The PLC electrical control system adopts a Siemens S7-1200 series CPU 1214C DC / DC / DC programmable logic controller, in conjunction with a KTP700 Basic touch screen human-machine interface. It is electrically connected to the spindle drive motor frequency converter, feed servo driver, hydraulic solenoid directional valve and high-pressure pump station to realize centralized automatic control of the drilling process.

[0015] In summary, compared with the prior art, this application includes at least one of the following beneficial technical effects: 1. This invention utilizes multiple drill bits to simultaneously complete the drilling of all oil holes in a single clamping, completely eliminating the reference transformation and cumulative errors caused by multiple clamping. Combined with the stable positioning reference provided by the self-centering positioning and axially adjustable stop, the axial position accuracy and circumferential phase accuracy of each oil hole can be reliably controlled within the design tolerance, ensuring the assemblability and sealing of the oil cylinder.

[0016] 2. This invention replaces sequential hole-by-hole machining with synchronous drilling, which greatly shortens the processing time of a single piece and directly solves the bottleneck problem of drilling in mass production, fully meeting the needs of mass production of hydraulic cylinders for coal mining machinery and other products.

[0017] 3. The present invention can provide stable constraints in both the radial and axial directions by combining a self-centering positioning seat with a swing-type clamping mechanism. The lever force amplification and adaptive fitting function of the clamping mechanism, combined with the elastic anti-slip pad on the positioning seat, ensure that the cylinder does not deflect radially or move axially under the action of drilling force, thus eliminating drilling deviation and chipping.

[0018] 4. This invention can accurately deliver coolant to the cutting edge through a high-pressure internal cooling liquid supply device, which can efficiently remove cutting heat and significantly reduce cutting temperature. The average life of carbide drill bits is greatly improved compared with external casting cooling, while improving hole diameter consistency and surface quality.

[0019] 5. This invention can use a negative pressure chip removal pipeline in conjunction with an annular chip collection hood to quickly remove chips and waste liquid from the processing area, avoiding long chips from wrapping around the drill bit or scratching the cylinder surface, and also eliminating the risk of abnormal drilling force and drill breakage caused by chip blockage.

[0020] 6. The spindle drilling system in this invention can be quickly adjusted or replaced to adapt to cylinders with different oil hole layouts; the self-centering positioning seat is compatible with cylinders of a certain diameter range; the axially adjustable stop can steplessly adapt to cylinders of different lengths, greatly reducing changeover time and tooling costs during multi-variety, variable-batch production, and has extremely high commercial value. Attached Figure Description

[0021] Figure 1 This is a front view of the drilling apparatus for producing hydraulic cylinders according to the present invention; Figure 2 For the present invention Figure 1 A partial sectional view of the structure; Figure 3 This is an isometric test diagram of the drilling device for producing hydraulic cylinders according to the present invention; Figure 4 This is a schematic diagram of the clamping device and cooling device in the drilling apparatus for producing hydraulic cylinders according to the present invention. Figure 5 This is a schematic diagram of the Zhuzhou drilling system and the cooling chip removal system in the drilling device for cylinder production of the present invention.

[0022] Explanation of reference numerals in the attached drawings: 100, Bed; 200, Spindle drilling system; 210, Drill bit; 220, Multi-axis drilling mechanism; 221, Gear transfer case; 222, Output spindle; 300, Workpiece clamping and positioning system; 310, Self-centering positioning seat; 311, Base; 312, V-block; 320, Swing clamping mechanism; 321, Hydraulic cylinder; 322, Swing arm; 323, Clamping block; 330, Axially adjustable stop block; 331, Stop block body; 332, Adjusting screw; 333, Locking nut; 400, Cooling and chip removal system; 410, High-pressure internal cooling liquid supply device; 411, High-pressure pump station; 412, Coolant filter; 420, Negative pressure chip removal pipeline. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings of the embodiments of the present invention. Figure 1-5 The technical solutions of the embodiments of the present invention will be clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0024] This invention provides a drilling device for hydraulic cylinder production, which solves the problems of poor oil hole positioning accuracy and low processing efficiency caused by multiple clamping and hole-by-hole drilling in the prior art. A front view schematic diagram of the overall structure of the device is shown below. Figure 3 As shown.

[0025] See Figure 1 , Figure 2 and Figure 3 As shown, the drilling device for hydraulic cylinder production includes a bed 100, a spindle drilling system 200, and a workpiece clamping and positioning system 300. The spindle drilling system 200 is mounted on the bed 100 and has multiple drill bits 210 for simultaneously drilling multiple oil holes on the cylinder barrel in a single clamping operation. The workpiece clamping and positioning system 300 is mounted on the worktable of the bed 100 and includes a self-centering positioning seat 310, a swing-type clamping mechanism 320, and an axially adjustable stop 330. The self-centering positioning seat 310 and the swing-type clamping mechanism 320 are arranged longitudinally at intervals along the worktable, and the axially adjustable stop 330 is located at the longitudinal end of the worktable.

[0026] The bed 100 is integrally cast from HT250 gray cast iron. HT250 gray cast iron has excellent vibration absorption and casting processability, effectively absorbing vibrations generated during drilling and ensuring the stability of machining accuracy. A wear-resistant hardened layer is formed on the worktable surface of the bed 100 through high-frequency induction hardening, with a hardness of HRC 45-55. High-frequency induction hardening involves placing the worktable surface in an alternating magnetic field generated by an induction coil. The skin effect of the induced current rapidly heats the surface layer above the austenitizing temperature, followed by rapid water cooling, transforming the surface structure into fine acicular martensite. This results in a high-hardness, high-wear-resistant hardened layer, while the core retains the original toughness and vibration absorption properties of gray cast iron. This wear-resistant hardened layer effectively resists wear caused by workpiece loading and unloading and chip splashing on the worktable surface, maintaining the flatness accuracy of the worktable surface even after long-term use.

[0027] like Figure 1 and Figure 4 As shown, the spindle drilling system 200 includes a mechanism for synchronously rotating multiple drill bits 210. In one specific implementation, the spindle drilling system 200 includes a spindle head, a spindle drive motor, a drill rod feed mechanism, and a multi-axis drilling mechanism 220. The spindle head is slidably mounted on the bed 100 via a column. A guide rail, machined by quenching and grinding, is mounted on the column, and a slider that slides along the guide rail is located on the back of the spindle head. The spindle drive motor is a YVF2-132M-4 type variable frequency speed-regulating three-phase asynchronous motor manufactured by Zhejiang Jinlong Motor Co., Ltd., with a rated power of 7.5kW. It can achieve stepless speed regulation within a frequency range of 5-100Hz. It is connected to the input shaft of the spindle head via a flexible coupling, transmitting rotational power to the gear transmission mechanism inside the spindle head. The drill rod feed mechanism drives the spindle head to move up and down along the column guide rail, and includes a servo motor, a precision planetary reducer, and a ball screw pair. The servo motor is an ECMA-C20807SS AC servo motor manufactured by Delta Electronics Co., Ltd., with a rated power of 750W. After torque amplification by a precision planetary reducer with a reduction ratio of 5:1, it drives the ball screw pair to rotate. The nut seat of the ball screw pair is fixedly connected to the spindle box. When the screw rotates, the nut seat drives the spindle box to rise and fall along the guide rail, realizing precise control of drilling feed and rapid retraction.

[0028] The multi-axis drilling mechanism 220 includes a gear transfer case 221 and multiple output spindles 222. The input end of the gear transfer case 221 is detachably connected to the output shaft of the spindle box via a tapered locking sleeve. The tapered locking sleeve utilizes the self-locking principle of the tapered surface to achieve a keyless connection, ensuring reliable torque transmission and facilitating quick replacement of multi-axis drilling mechanisms 220 of different specifications. The spatial layout of the multiple output spindles 222 on the output side of the gear transfer case 221 corresponds to the distribution of oil holes on the cylinder barrel to be machined. The gear transfer case 221 internally employs multiple sets of cylindrical helical gear transmission pairs. Each gear is made of 20CrMnTi carburized and quenched steel with a tooth surface hardness of HRC 58-62 and a gear precision grade of national standard 6. After carburizing, quenching, and low-temperature tempering, 20CrMnTi steel achieves a high-carbon martensitic structure on the tooth surface, exhibiting extremely high contact fatigue strength and wear resistance. The core retains a mixed structure of low-carbon martensite and ferrite, providing good toughness and enabling it to withstand impact loads generated during drilling. The gear transfer case 221, through the precise transmission ratio design of each gear pair, ensures that all output spindles 222 rotate completely synchronously under the drive of the input shaft, with a constant phase difference of zero. This ensures that each drill bit 210 simultaneously contacts the workpiece surface and completes drilling synchronously. Each drill bit 210 is clamped onto its corresponding output spindle 222 via an ER32 spring collet. The drill bit 210 is a carbide internally cooled twist drill, and its interior has a through-flow coolant channel along the axial direction.

[0029] It should be noted that the method by which the spindle drilling system 200 simultaneously drills multiple oil holes is not limited to the multi-axis drilling mechanism 220 described above. In other embodiments, multiple independent electric spindles can be fixed on the spindle box according to a preset spatial layout, and the electronic synchronous rotation of each electric spindle can be achieved through a servo control system, which also falls within the protection scope of this invention.

[0030] like Figure 1 and Figure 5As shown, the self-centering positioning seat 310 in the workpiece clamping and positioning system 300 is used for radial positioning of the cylinder and automatic centering of its axis. In a preferred embodiment, the self-centering positioning seat 310 includes a base 311 and two opposing V-blocks 312. The base 311 is fixed to the worktable surface by bolts, and the two V-blocks 312 are arranged laterally opposite each other along the worktable surface, with their V-shaped surfaces facing each other to form a V-shaped positioning space for accommodating the cylinder. The V-angle is 90°, which allows cylindrical workpieces of different diameters to automatically slide into the bottom of the V-groove under gravity or external force to achieve axial centering and achieve a self-centering effect. Each V-block 312 has a wear-resistant liner layer on its V-shaped surface, which is made of polyurethane elastomer material and is bonded to the V-block 312 substrate through a hot vulcanization process. The hot vulcanization process involves injecting the mixed polyurethane prepolymer and curing agent into a mold, and then curing it under heat and pressure on the surface of the V-block 312 matrix. This creates a strong bond between the liner layer and the matrix, forming a chemically bonded and mechanically interlocked interface, preventing the liner layer from peeling off after long-term use. The surface of the wear-resistant liner layer has a textured anti-slip groove, approximately 0.5 mm deep and 2 mm apart. This textured anti-slip groove increases the coefficient of friction between the liner layer and the outer surface of the cylinder. When the cylinder is subjected to drilling torque, the groove edges embed into the microscopic irregularities on the cylinder surface, creating a mechanical locking effect that effectively prevents workpiece deflection. Simultaneously, the polyurethane elastomer itself has an appropriate elastic modulus and good resilience, allowing for slight elastic deformation under clamping force. This compensates for dimensional deviations in the cylinder's outer diameter within tolerance limits, ensuring stable contact between different batches of cylinders and preventing scratches or damage to the outer surface of the cylinder due to hard contact.

[0031] The swing-type clamping mechanism 320 is used to apply radial clamping force to the cylinder from above, and cooperates with the self-centering positioning seat 310 to form an upper and lower clamping of the cylinder. Preferably, the swing-type clamping mechanism 320 is a hydraulic swing-type clamping mechanism 320, which includes a hydraulic cylinder 321, a swing arm 322, and a clamping block 323. The cylinder body of the hydraulic cylinder 321 is hinged to the worktable by an ear pin, allowing it to swing within a certain angle around the hinge point to compensate for changes in the installation angle of the hydraulic cylinder 321 during the movement of the swing arm 322. The hydraulic cylinder 321 is driven by an independent hydraulic pump station, which uses a VP-20-FA3 type variable vane pump manufactured by Beibu Precision Machinery Co., Ltd., with a rated pressure of 7MPa. It is used in conjunction with a 4WE6J61 type three-position four-way solenoid directional valve manufactured by Huade Hydraulics to control the extension and retraction direction and speed of the hydraulic cylinder 321. The three-position four-way solenoid directional valve has a neutral position function, which can keep the position of the hydraulic cylinder 321 unchanged when the power is off, achieving pressure holding and clamping. One end of the swing arm 322 is hinged to the piston rod end of the hydraulic cylinder 321 via a pin, and the middle part of the swing arm 322 is rotatably mounted on the worktable via a hinge support. The hinge support is fixed to the worktable, and the swing arm 322 can swing in a vertical plane around the pin of the hinge support, forming a lever mechanism. The lever arm ratio of the swing arm 322 is designed to be 2:1, meaning the lever arm of the hydraulic cylinder 321 is twice the clamping lever arm, so that the thrust output by the hydraulic cylinder 321 is amplified by the swing arm 322 and applied to the workpiece, achieving force-increasing clamping. The clamping block 323 is connected to the end of the swing arm 322 away from the hydraulic cylinder 321 via a ball joint. The ball joint consists of a ball head pin and a ball socket; the ball head pin can deflect at a certain angle in any direction within the ball socket, giving the clamping block 323 universal self-adaptive fitting capability. The clamping surface of the clamping block 323 is an arc-shaped surface adapted to the outer circular surface of the cylinder barrel, and the radius of curvature of the arc-shaped surface matches the outer radius of the cylinder barrel to be processed. An elastic buffer layer made of nitrile rubber with a thickness of approximately 3 mm is provided on the arc-shaped surface. Nitrile rubber has good oil resistance and wear resistance, providing elastic cushioning when in contact with the cylinder barrel surface, avoiding direct metal-to-metal contact that could cause indentations on the workpiece surface. Simultaneously, its high coefficient of friction further increases the friction between the clamping surface and the cylinder barrel, enhancing the anti-rotation effect.

[0032] It should be noted that the power source of the swing-type clamping mechanism 320 is not limited to hydraulic means. In other embodiments, a cylinder, an electric push rod, or a motor-driven cam mechanism can also be used as the power source, as long as it can drive the swing arm 322 to swing around the hinge support and apply clamping force to the workpiece. These modifications are all within the protection scope of this invention.

[0033] The axially adjustable stop 330 provides an axial positioning reference for cylinders of different lengths. It includes a stop body 331, an adjusting screw 332, and a locking nut 333. The stop body 331 is made of 45# steel and has undergone heat treatment, achieving a hardness of HB220-250, providing excellent comprehensive mechanical properties. The stop body 331 is slidably mounted on the longitudinal end of the worktable via a slide rail pair. The slide rail pair consists of a guide rail fixed to the worktable and a slider fixed to the bottom of the stop body 331. The guide rail has a rectangular cross-section, and the slider contains a wear-resistant copper alloy guide plate to ensure smooth sliding and adjustable clearance. The adjusting screw 332 is axially limited and mounted on the worktable via a bearing housing. The bearing housing contains a pair of angular contact ball bearings to bear the axial load of the screw and ensure flexible rotation. A handwheel is located at the front end of the adjusting screw 332 for easy manual rotation by the operator. The threaded section of the adjusting screw 332 engages with the threaded hole on the stop body 331. When the adjusting screw 332 is rotated, the rotational motion of the screw is converted into linear movement of the stop body 331 along the slide rail pair through threaded transmission, achieving stepless adjustment of the axial position of the stop body 331. The locking nut 333 is screwed onto the adjusting screw 332 and located on one side of the stop body 331. After the stop body 331 is adjusted to the correct position, the locking nut 333 is tightened so that its end face presses against the end face of the stop body 331 or the bearing seat. The threaded friction torque is used to lock the stop body 331 in the current axial position, preventing displacement due to axial force during drilling.

[0034] As a further improvement, the device also includes a cooling chip removal system 400. The cooling chip removal system 400 includes a high-pressure internal cooling fluid supply device 410. The high-pressure internal cooling fluid supply device 410 is connected to the internal coolant channel of the drill pipe and is used to directly deliver high-pressure coolant to the cutting area of ​​the drill bit 210. The high-pressure internal cooling fluid supply device 410 includes a high-pressure pump station 411 and a coolant filter 412. The high-pressure pump station 411 uses a CDL8-8 vertical multistage centrifugal pump manufactured by Guangdong Lingxiao Pump Industry Co., Ltd., with a rated flow rate of 8 m³ / h, a rated head of 72 m, and a motor power of 3 kW. The vertical multistage centrifugal pump, through the series connection of multiple impellers, progressively increases the pressure, outputting a stable and high-pressure coolant flow. The coolant uses a 5%-8% concentration of semi-synthetic cutting fluid, which combines good cooling, lubrication, and rust prevention properties. The coolant filter 412 is a pipeline-type precision filter with a filtration accuracy of 10μm. It is installed in the outlet pipeline of the high-pressure pump station 411 to filter out cutting particles and impurities in the coolant, preventing blockage of the small coolant channels inside the drill bit 210. The filtered high-pressure coolant is transported to the rotary joint via pipeline. The rotary joint is installed at the end of the output shaft of the spindle box. The rotating seal between the moving and stationary rings inside the joint uses a silicon carbide ceramic sealing surface to achieve a rotary seal for the high-pressure fluid, transferring the coolant from the stationary pipeline to the coolant channels inside the rotating drill rod without leakage. The coolant channels inside the drill rod run along the entire length of the drill rod along the axis, with a diameter of approximately 4mm. Two coolant ejection holes with a diameter of approximately 1.5mm are provided at the cutting edge of the drill bit 210. The high-pressure coolant is ejected at high speed from the ejection holes, directly impacting the cutting area, quickly removing cutting heat and lubricating the cutting interface.

[0035] Preferably, the cooling chip removal system 400 further includes a negative pressure chip removal pipe 420. The negative pressure chip removal pipe 420 is connected to an annular chip collection hood surrounding the drilling area. The annular chip collection hood is mounted on the worktable and is composed of upper and lower halves. The hood is made of transparent polycarbonate sheet, hot-bent to facilitate operator observation of the drilling process. The hood surrounds the workpiece and the machining area of ​​the drill bit 210, preventing chips and coolant from splashing. A funnel-shaped chip collection hopper is located at the bottom of the annular chip collection hood, with a chip discharge port at the bottom. The chip discharge port is connected to the negative pressure chip removal pipe 420 via a DN50 stainless steel corrugated pipe. The end of the negative pressure chip removal pipe 420 is connected to a centralized chip removal box. A vortex negative pressure fan is installed on the pipe, with an airflow of 1200 m³ / h and an air pressure of 2500 Pa. After the vortex negative pressure fan starts, it generates a continuous negative pressure suction force in the pipeline, drawing the mixture of chips and coolant produced during drilling through the chip collection hopper into the chip removal pipeline and then to the centralized chip removal box for filtration and separation. The inner wall of the annular chip collection hood is also equipped with fan-shaped atomizing coolant nozzles, facing the drilling area, to assist in flushing residual chips on the workpiece surface and in the drill bit 210 groove, further improving the chip removal effect.

[0036] As a further improvement, the device also includes a PLC electrical control system. The PLC electrical control system uses a Siemens S7-1200 series CPU 1214C DC / DC / DC programmable logic controller, paired with a Siemens KTP700 Basic 7-inch touchscreen human-machine interface. The CPU 1214C has 14 digital inputs and 10 digital outputs, and a built-in PROFINET communication interface for easy communication with frequency converters and servo drives. The KTP700 Basic touchscreen connects to the CPU via Ethernet, providing a graphical user interface that displays real-time operating parameters such as spindle speed, feed rate, hydraulic pressure, and coolant flow rate. It also offers manual and automatic cycle modes for operator selection. The PLC electrical control system is electrically connected to the frequency converter of the spindle drive motor, the servo driver of the feed mechanism, the solenoid directional valve of the hydraulic system, the contactor of the high-pressure pump station 411, and the contactor of the negative pressure fan. Through program control of each actuator, the entire drilling process is automatically and sequentially executed, including actions such as workpiece clamping, spindle start and stop, coolant supply, chip removal fan start and stop, rapid approach, feed drilling, and rapid retraction.

[0037] Example This embodiment provides a specific implementation case of applying the above-mentioned drilling device for hydraulic cylinder production to the drilling of oil holes in the cylinder barrel of a column hydraulic cylinder for coal mining machinery.

[0038] The cylinder barrel of the hydraulic cylinder to be machined is made of 27SiMn quenched and tempered steel, with an outer diameter of Φ180mm, a wall thickness of 10mm, and a length of 1200mm. Three oil holes need to be machined on the cylinder barrel, two of which are oil inlets and one is an oil return. The three holes are spaced 200mm and 300mm apart along the axial direction of the cylinder barrel, and are evenly distributed at 120° in the circumferential direction.

[0039] The specific configurations of each component of the device are as follows: The bed 100 is fixed to the foundation with anchor bolts. The worktable of the bed 100 has a size of 2000mm×600mm and a hardness value of HRC 50 after high frequency induction hardening.

[0040] The spindle box is slidably mounted on the column via hardened guide rails. The spindle drive motor is a YVF2-132M-4 type variable frequency speed control motor manufactured by Zhejiang Jinlong Electric Co., Ltd., with a rated power of 7.5kW and a rated speed of 1440r / min. In the feed mechanism, the servo motor is a Delta ECMA-C20807SS type, and the ball screw pair has a lead of 5mm.

[0041] The input end of the gear transfer case 221 of the multi-axis drilling mechanism 220 is connected to the output shaft of the spindle box via a tapered locking sleeve. The case contains three output spindles 222, arranged according to the axial spacing and circumferential distribution requirements of the cylinder oil holes. Each gear is a 20CrMnTi carburized and quenched gear with a tooth surface hardness of HRC 60 and a speed ratio of 1:1. Three drill bits 210 are Φ8mm carbide internally cooled twist drills, clamped onto each output spindle 222 via ER32 spring collets.

[0042] The two V-blocks 312 of the self-centering positioning seat 310 are 400mm apart, and the included angle of the V-shaped surfaces is 90°. The wear-resistant liner is formed by hot vulcanization of polyurethane elastomer on the V-shaped surface, and the surface of the liner is processed with a mesh-like anti-slip groove with a depth of 0.5mm and a spacing of 2mm.

[0043] Two sets of swing-type clamping mechanisms 320 are arranged symmetrically along the longitudinal direction of the worktable on the front and rear sides of the self-centering positioning seat 310. In each set of mechanisms, the hydraulic cylinder 321 has a cylinder diameter of 40mm, a piston rod diameter of 20mm, and a stroke of 80mm. The swing arm 322 has a length of 300mm and a lever arm ratio of 2:1, that is, the hydraulic cylinder 321 has an action lever arm of 200mm and a clamping lever arm of 100mm. The radius of curvature of the arc surface of the clamping block 323 is R90mm, which is consistent with the outer radius of the cylinder barrel R90mm. The elastic buffer pad is made of nitrile rubber with a thickness of 3mm. The hydraulic pump station adopts the Beibu Jingji VP-20-FA3 type variable vane pump with a rated pressure of 7MPa, and the electromagnetic reversing valve is the Huade Hydraulic 4WE6J61 type.

[0044] In the axially adjustable stop 330, the stop body 331 is made of 45# steel, heat-treated, with a hardness of HB 230. The adjusting screw 332 is a Tr20×4 trapezoidal screw with a single-threaded lead of 4mm. The handwheel diameter is 120mm. The locking nut 333 is an M20×1.5 fine-pitch nut with a spring washer to prevent loosening.

[0045] The high-pressure pump station 411 of the cooling chip removal system 400 uses a Lingxiao CDL8-8 vertical multistage centrifugal pump. The coolant is a 6% concentration semi-synthetic cutting fluid, which enters the coolant channel inside the drill pipe through a rotary joint after passing through a 10μm pipe filter. The annular chip collection hood is made of transparent polycarbonate plate, with four fan-shaped atomizing nozzles installed on the inside. The negative pressure chip removal pipeline 420 has a diameter of DN50 and is connected to the centralized chip removal box. The vortex negative pressure fan has an air volume of 1200 m³ / h and an air pressure of 2500 Pa.

[0046] The PLC control system uses a Siemens CPU 1214C DC / DC / DC programmable logic controller and a KTP700 Basic touch screen. The control cabinet is equipped with electrical components such as frequency converters, servo drives, contactors and relays, and realizes two operation modes, manual and automatic cycle, through the program.

[0047] The operation method for drilling holes in the cylinder barrel of the column hydraulic cylinder using the above-mentioned device is as follows: Step 1: Preparation. Check the hydraulic pump station oil level, the high-pressure pump station 411 coolant level, and the unobstructed condition of the negative pressure chip removal pipe 420. Set the process parameters via the touchscreen: spindle speed 800 r / min, feed rate 0.15 mm / r, drilling depth 12 mm (cylinder wall thickness 10 mm plus 2 mm safety margin), rapid approach speed 3000 mm / min, rapid return speed 5000 mm / min.

[0048] Step 2, workpiece clamping. The overhead crane lifts the cylinder barrel to be processed onto the worktable, slowly lowers it, and places it smoothly onto the two V-blocks 312 of the self-centering positioning seat 310, with the outer surface of the cylinder barrel in contact with the wear-resistant liner. The operator rotates the adjusting screw 332 handwheel to move the stop block body 331 axially along the slide rail until it is flush with the rear end face of the cylinder barrel. The locking nut 333 is then tightened to complete axial positioning. The automatic clamping program is triggered via the touchscreen. The PLC controls the solenoid directional valve to switch to the feed position, and the pressure oil output from the hydraulic pump station enters the rodless chamber of the hydraulic cylinder 321. The piston rod extends, pushing the swing arm 322 to swing around the hinged support. The clamping block 323 adaptively conforms to the upper surface of the cylinder barrel under the action of the ball joint. After the hydraulic pressure rises to the set value, the pressure relay sends a signal, and the solenoid directional valve switches to the neutral position for pressure holding, completing the workpiece clamping.

[0049] Step 3, Start Machining. Close the safety door and start the automatic drilling program via the touchscreen. The PLC executes the following actions sequentially according to the preset program: the spindle drive motor starts, and after a 0.5-second delay, the high-pressure pump station 411 and the negative pressure fan start; the servo motor drives the ball screw pair to make the spindle box descend at a rapid approach speed, switching to the feed speed when the tip of the drill bit 210 is 3mm away from the cylinder surface; the three drill bits 210 simultaneously cut into the cylinder wall for drilling, and when the drilling depth reaches the set value of 12mm, the PLC receives the position signal from the servo motor encoder and controls the servo motor to reverse, and the spindle box rises back to its original position at a rapid return speed; the spindle motor stops, and the high-pressure pump station 411 and the negative pressure fan stop after a 2-second delay.

[0050] Step 4, Unloading Inspection. Open the safety door and trigger the workpiece release command via the touchscreen. The electromagnetic reversing valve switches to the return position, oil enters the rod chamber of hydraulic cylinder 321, the piston rod retracts, and the swing arm 322 swings in the opposite direction, causing the clamping block 323 to rise and release the workpiece. The operator removes the machined cylinder and uses an inside micrometer to check the diameter of the three oil holes. A coordinate measuring machine is used to check the axial spacing and circumferential position of the holes. The inspection shows that the diameters of the three oil holes are all within the range of Φ8±0.05mm, the axial spacing deviation does not exceed ±0.08mm, the circumferential position error does not exceed 0.1mm, and the surface roughness of the hole wall reaches Ra3.2μm. The single-piece machining cycle is approximately 3 minutes (including clamping and unloading time). After passing the inspection, the next cylinder is clamped and machined.

[0051] After processing 500 cylinders, a random inspection showed that the hole diameter remained stable within the tolerance range, the hole position accuracy did not decrease significantly, and the wear of the 210 drill bit edge was about 0.1 mm. This indicates that the high-pressure internal cooling method effectively reduced the cutting temperature and extended the tool life.

[0052] As can be seen from the above embodiments, the drilling device for hydraulic cylinder production provided by the present invention can simultaneously drill multiple oil holes with multiple drill bits 210 in one clamping, and achieve high-precision and high-efficiency machining of oil holes in hydraulic cylinder barrels by combining a composite clamping and positioning system consisting of a self-centering positioning seat 310, a swing-type clamping mechanism 320 and an axially adjustable stop block 330.

[0053] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A drilling device for hydraulic cylinder production, comprising a bed (100), and a spindle drilling system (200) and a workpiece clamping and positioning system (300) disposed on the bed (100), characterized in that, The spindle drilling system (200) has multiple drill bits (210) for simultaneously drilling multiple oil holes on the cylinder barrel of the hydraulic cylinder in one clamping operation; the workpiece clamping and positioning system (300) includes a self-centering positioning seat (310), a swing clamping mechanism (320) and an axially adjustable stop (330). The self-centering positioning seat (310) and the swing clamping mechanism (320) are arranged longitudinally at intervals along the worktable surface of the bed (100), and the axially adjustable stop (330) is located at the longitudinal end of the worktable surface.

2. The drilling device for hydraulic cylinder production as described in claim 1, characterized in that: The spindle drilling system (200) includes a multi-axis drilling mechanism (220), which includes a gear transfer box (221) and multiple output spindles (222). The input end of the gear transfer box (221) is connected to the output shaft of the spindle box. The multiple output spindles (222) are arranged in a spatial layout corresponding to the distribution position of the oil holes. The drill bit (210) is respectively installed on each of the output spindles (222).

3. The drilling device for hydraulic cylinder production as described in claim 1, characterized in that: The self-centering positioning seat (310) includes a base (311) and two opposing V-shaped blocks (312). Wear-resistant pads are provided on the V-shaped surfaces of the two V-shaped blocks (312), and anti-slip grooves are provided on the surface of the wear-resistant pads.

4. The drilling device for hydraulic cylinder production as described in claim 1, characterized in that: The swing-type clamping mechanism (320) is a hydraulic swing-type clamping mechanism (320), which includes a hydraulic cylinder (321), a swing arm (322) and a clamping block (323). The cylinder body of the hydraulic cylinder (321) is hinged to the worktable. One end of the swing arm (322) is hinged to the piston rod of the hydraulic cylinder (321), and the middle part is hinged to the worktable. The clamping block (323) is connected to the other end of the swing arm (322) through a ball joint. The clamping surface of the clamping block (323) is an arc-shaped surface that matches the outer circular surface of the cylinder.

5. The drilling device for hydraulic cylinder production as described in claim 1, characterized in that: The axially adjustable stop (330) includes a stop body (331), an adjusting screw (332), and a locking nut (333). The stop body (331) is slidably mounted on the longitudinal end of the worktable. The adjusting screw (332) is threadedly connected to the stop body (331) to adjust its axial position. The locking nut (333) is used to lock the stop body (331).

6. The drilling device for hydraulic cylinder production as described in claim 1, characterized in that: It also includes a cooling chip removal system (400), which includes a high-pressure internal cooling liquid supply device (410) that is connected to the internal coolant channel of the drill pipe.

7. The drilling device for hydraulic cylinder production as described in claim 6, characterized in that: The cooling chip removal system (400) also includes a negative pressure chip removal pipe (420), which is connected to an annular chip collection hood surrounding the drilling area.

8. The drilling device for hydraulic cylinder production as described in claim 7, characterized in that: The high-pressure internal cooling fluid supply device (410) includes a high-pressure pump station (411) and a coolant filter (412). The high-pressure pump station (411) is connected to a rotary joint through the coolant filter (412). The rotary joint is connected to the coolant channel inside the drill pipe.

9. The drilling apparatus for producing hydraulic cylinders as described in any one of claims 1 to 8, characterized in that, The worktable surface of the bed (100) has a wear-resistant quenching layer.

10. The drilling apparatus for cylinder manufacturing as described in any one of claims 1 to 8, characterized in that, It also includes a PLC electrical control system, which is electrically connected to the spindle drilling system (200) and the workpiece clamping and positioning system (300).

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