A method for processing a double deep hole piston rod channel

Abstract

The application provides a double-deep-hole piston rod hole processing method, adopts a special combined cutter to process a joint hole, the special combined cutter comprises a cutter body, two reamer blades, an expanding cutter blade, a waist chamfer blade and two tail chamfer blades, two chip removal grooves are symmetrically arranged on the two sides of the cutter body, the two chip removal grooves extend from the front end of the cutter body to the rear part of the cutter body, the two reamer blades are respectively arranged at the front end of the two chip removal grooves; the expanding cutter blade is arranged in the middle part of one chip removal groove, the waist chamfer blade is arranged in the middle part of the other chip removal groove; the two tail chamfer blades are respectively arranged at the tail part of the two chip removal grooves, two internal cooling holes are arranged in the cutter body, and the liquid outlet ends of the internal cooling holes are located near the reamer blades; and the method comprises the following steps: S1, calculating the deep hole position; S2, drilling the deep hole; S3, drilling the counterbore of the joint hole; S4, drilling the hole by the special combined cutter; S5, finishing the sealing fit hole; and S6, processing the internal thread.

Description

Technical Field

[0001] This invention relates to the field of piston rod machining, and more specifically, to a method for machining double deep-hole piston rod channels. Background Technology

[0002] Hydraulic supports in coal mines are crucial support equipment for underground coal mining. Hydraulic actuators such as columns and jacks are essential components of these supports. The reliability and stability of the jacks affect the normal operation of the entire hydraulic support system and its overhaul intervals. With the development of the coal mining machinery manufacturing industry, the support height of hydraulic supports is increasing, and the types of hydraulic cylinders are becoming more diverse. As various hydraulic pipeline interfaces are standardized, the dimensions of the boreholes on the piston rod also need to be adjusted accordingly. The boreholes on the piston rod mainly include two deep holes extending axially and two connecting holes arranged radially. The connecting holes connect to the front end of the deep holes for fluid flow.

[0003] The traditional method for machining the bore in a piston rod mainly consists of two parts: the first part involves machining two deep holes using deep-hole drilling; the second part involves machining two connector holes, such as... Figure 1 This is a schematic diagram of the piston rod connector hole structure, including countersunk hole 1, chamfer 2, sealing mating hole 3, threaded connection hole 4, and threaded bottom hole 5. The sealing mating hole 3 mainly serves a sealing function, and the surface roughness requirement is Ra1.6. The threaded connection hole 4 is used for threaded connection with the external hydraulic pipe connector. The coaxiality of the sealing mating hole 3 and the threaded connection hole 4 must not exceed 0.03 mm. Otherwise, it will not fit well with the hydraulic pipe connector, the rubber sealing ring will be unevenly compressed, resulting in a reduced sealing ring life. Excessive deviation will also cause leakage and affect the service life of the jack.

[0004] In traditional methods, when machining two deep holes, the machining is generally carried out on the same plane as the central shaft. Since the diameters of piston rods of different specifications are different, in order to ensure that the joint hole can be drilled through the deep hole, the traditional method for machining the joint hole is to machine the countersunk hole 1, rough machine the sealing mating hole 3, machine the threaded bottom hole 5 (including the threaded connection hole 4 sections), machine the chamfer 2, use a tap to machine the thread on the threaded connection hole 4, and finish machine the sealing mating hole 3. Each process uses an independent tool, which makes it easy to control the depth of the joint hole.

[0005] Traditional processing methods have the following disadvantages: (1) The processing steps of the joint hole are complicated and the overall processing efficiency of the hole is low; (2) Frequent tool changes are required in the actual processing process, resulting in high management costs; (3) Tool changes are required for each process, and the coaxiality of each hole is difficult to control, making it difficult to achieve a high level of processing accuracy.

[0006] To address the aforementioned problems, technical personnel have been continuously exploring and searching for ideal technical solutions. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for machining double deep-hole piston rod channels that is applicable to piston rods of different specifications, requires no frequent tool changes during machining, and has high machining efficiency and precision.

[0008] To achieve the above objectives, the technical solution adopted by this invention is: a method for machining a double deep-hole piston rod channel, wherein the channel includes two deep holes and two connector holes, and the connector holes include a countersunk hole, a chamfer at the bottom of the countersunk hole, a sealing mating hole, a threaded connection hole, and a threaded bottom hole connected in sequence. A special combination tool is used to machine the connector holes. The special combination tool includes a tool body, two reamer inserts, one reamer insert, one waist chamfering insert, and two tail chamfering inserts. Two chip removal grooves are symmetrically formed on both sides of the tool body, extending from the front end to the rear end of the tool body. The two reamer inserts are respectively installed at the front ends of the two chip removal grooves; the reamer insert is installed in the middle of one chip removal groove, and the waist chamfering insert is installed in the middle of the other chip removal groove; the two tail chamfering inserts are respectively installed at the tail ends of the two chip removal grooves. The tool body has two internal cooling holes, with the liquid outlet of the internal cooling holes located near the reamer inserts. The method for machining a double deep-hole piston rod channel includes the following steps:

[0009] S1. Calculate the position of the deep hole: Let the diameter of the piston rod head be D1, the countersunk hole depth in the joint hole be h1, and the drilling depth of the special combination tool be h2. When D1 / 2-h1-h2≤0, the line connecting the centers of the two deep holes passes through the central axis of the piston rod. When D1 / 2-h1-h2>0, the distance e between the line connecting the centers of the two deep holes and the central axis of the piston rod is D1 / 2-h1-h2.

[0010] S2. Drilling deep holes: Drill two deep holes using a deep hole drilling machine.

[0011] S3, Countersunk hole of drill joint: Countersunk hole is milled on piston rod head, and the machining is completed in one feed;

[0012] S4. Drilling with the special combination tool: Replace the tool with the special combination tool, input high-pressure coolant into the two reamer blades through the internal cooling hole, and spray low-speed coolant on the outside of the special combination tool. The two reamer blades rough machine the threaded connection hole and the threaded bottom hole. The waist chamfering blade machine the chamfer at the bottom of the sealing mating hole. The reamer blade rough machine the sealing mating hole. The tail chamfering blade machine the chamfer at the bottom of the countersunk hole.

[0013] S5. Finish machining of the sealing mating hole: Replace the special combination tool with a boring tool and finish bore the sealing mating hole;

[0014] S6. Machining internal threads: Use a tap to machine internal threads in the threaded connection hole.

[0015] Based on the above, the reamer insert adopts a square insert with a positive rake angle, and the main cutting edge of the reamer insert forms an angle of 88° with the axis of the cutter body.

[0016] Based on the above, the chamfer at the bottom of the countersunk hole and the chamfer at the bottom of the sealing mating hole are both 45°.

[0017] Based on the above, in step S4, the sealing mating hole retains a machining allowance of 0.5mm.

[0018] This invention has significant substantive features and remarkable progress compared to existing technologies. Specifically, based on the machining depth of the dedicated combination tool and the diameter of the piston rod head, the invention first calculates the machining positions of the two deep holes. When D1 / 2-h1-h2>0, the two deep holes need to be eccentrically offset by a corresponding distance to ensure that the threaded bottom hole can be connected to the deep hole. The invention also designs the dedicated combination tool based on the structure of the connector hole, first machining the countersunk hole separately, and then using the dedicated combination tool to rough machine the bottom chamfer of the countersunk hole, the sealing mating hole, the threaded connection hole, and the threaded bottom hole in one operation. However, the actual machined threaded bottom hole will have a sharp edge at the opening, which not only increases the difficulty of subsequent tapping but also easily leads to thread retraction problems during assembly. This patent utilizes the waist chamfering insert in the sealing... A chamfer is machined at the bottom of the mating hole to prevent the sharp edge at the opening of the threaded bottom hole from extending into the sealing mating hole, thus solving the aforementioned problem. Two internal cooling holes allow high-pressure coolant to be introduced to the bottom of the hole, cooling the reamer inserts and providing excellent chip breaking as the high-pressure coolant flows from the bottom to the opening, preventing chips from affecting machining accuracy or entangled in the tool. The low-speed coolant provides auxiliary cooling to the reamer inserts, the waist chamfer inserts, and the tail chamfer inserts from the outside, effectively solving both chip breaking and cooling issues. Finally, a boring tool is used to finish the sealing mating hole, and a tap is used to machine the internal thread in the threaded connection hole. Compared with traditional machining methods, this method has the advantages of being applicable to piston rods of different specifications, eliminating the need for frequent tool changes during machining, and offering high machining efficiency and accuracy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the traditional piston rod connector hole structure in the background technology.

[0020] Figure 2 This is a schematic diagram of the piston rod structure processed in this invention.

[0021] Figure 3 This is a schematic diagram of the structure of the special combined cutting tool in this invention.

[0022] Figure 4 This is a schematic diagram of the connector hole joint processed in this invention.

[0023] In the diagram: 1. Countersunk hole; 2. Chamfer; 3. Sealing mating hole; 4. Threaded connection hole; 5. Threaded pilot hole; 6. Tool body; 7. Reamer insert; 8. Expander insert; 9. Waist chamfering insert; 10. Tail chamfering insert; 11. Chip removal groove; 12. Internal cooling hole; 13. Deep hole; 14. Piston rod; 15. Connector hole. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0025] like Figure 2-4 As shown, a method for machining a double deep-hole piston rod channel is described. The channel includes two deep holes 13 and two connector holes 15. The connector hole 15 includes a countersunk hole 1, a chamfer 2 at the bottom of the countersunk hole 1, a sealing mating hole 3, a threaded connection hole 4, and a threaded bottom hole 5 connected in sequence. This is a common double deep-hole piston rod structure.

[0026] To improve processing efficiency, this patent uses a special combination tool to process the joint hole 15. The special combination tool includes a tool body 6, two reamer blades 7, one expanding blade 8, one waist chamfering blade 9, and two tail chamfering blades 10. The tool body 6 has two symmetrical chip removal grooves 11 on both sides, extending from the front end to the rear end of the tool body 6. The two reamer blades 7 are respectively installed at the front ends of the two chip removal grooves 11. The expanding blade 8 is installed in the middle of one chip removal groove 11, and the waist chamfering blade 9 is installed in the middle of the other chip removal groove 11. The two tail chamfering blades 10 are respectively installed at the tail ends of the two chip removal grooves 11. The tool body 6 has two internal cooling holes 12, with the outlet end of the internal cooling hole 12 located near the reamer blades 7. The method for processing the double deep-hole piston rod channel includes the following steps:

[0027] S1. Calculate the position of deep hole 1: Let the diameter of the piston rod 14 head be D1, the depth of the countersunk hole 1 in the connector hole 15 be h1, and the drilling depth of the special combination tool be h2. When D1 / 2-h1-h2≤0, the line connecting the centers of the two deep holes 13 passes through the central axis of the piston rod 14. When D1 / 2-h1-h2>0, the distance e between the line connecting the centers of the two deep holes 13 and the central axis of the piston rod 14 is e= D1 / 2-h1-h2. This ensures that after the special combination tool drills, the threaded bottom hole 5 can communicate with the deep hole 13.

[0028] S2, Drilling deep holes 13: Drill two deep holes 13 on a deep hole drilling machine.

[0029] S3, Countersunk hole 1 of drill joint hole 15: Countersunk hole 1 is milled on the piston rod 14 head and the machining is completed in one feed.

[0030] S4. Drilling with the special combination tool: Replace the tool with the special combination tool. High-pressure coolant is introduced into the two reamer blades 7 through the internal cooling hole 12. On the one hand, it cools the reamer blades 7. On the other hand, the high-pressure coolant can achieve a good chip breaking effect as it flows from the bottom of the hole to the opening, avoiding the impact of iron chips on the machining accuracy or entanglement of the tool. At the same time, low-speed coolant is sprayed on the outside of the special combination tool to provide auxiliary cooling for the reamer blade 8, the waist chamfering blade 9 and the tail chamfering blade 10.

[0031] It should be noted that during the research and development process, the applicant also opened a total of four internal cooling holes for the two reamer blades 7, the reamer blade 8 and the waist chamfering blade 9. However, the high-pressure coolant in the waist of this structure would suppress the iron filings, causing them to be unable to be discharged smoothly. This embodiment solves the problem well.

[0032] During the machining process, the two reamer inserts 7 rough-machine the threaded connection hole 4 and the threaded bottom hole 5, the waist chamfering insert 9 machines the chamfer 2 at the bottom of the sealing mating hole 3, the expanding insert 8 rough-machines the sealing mating hole 3, where the sealing mating hole 3 retains a machining allowance of 0.5mm, and the tail chamfering insert 10 machines the chamfer 2 at the bottom of the countersunk hole 1; in this embodiment, the chamfer 2 at the bottom of the countersunk hole 1 and the chamfer 2 at the bottom of the sealing mating hole 3 are both 45°.

[0033] It should be noted that during the research and development process, the applicant did not originally design the chamfer 2 at the bottom of the sealing mating hole 3. However, the actual machined threaded bottom hole 5 had a sharp edge at the opening, which not only increased the difficulty of subsequent tapping but also made it easy for the threads to be difficult to reconnect during assembly. This patent uses the waist chamfering blade 9 to machine the chamfer 2 at the bottom of the sealing mating hole 3, so that the sharp edge at the opening of the threaded bottom hole 5 will not extend into the sealing mating hole 3, thus solving the above problems.

[0034] In this embodiment, the reamer insert 7 specifically needs to be a square insert with a positive rake angle. To avoid the secondary cutting edge participating in cutting and increasing the cutting force, the main cutting edge of the reamer insert 7 forms an 88° angle with the axis of the tool body 6. In other embodiments, the applicant selects a rhomboid insert with a positive rake angle for the reamer insert 7, with an acute angle of 80°. However, since the threaded bottom hole 5 intersects with the deep hole 13, intermittent cutting will occur when machining to the position of the deep hole 13. In addition, due to the unremoved iron filings, the 80° tool tip is prone to chipping. In this embodiment, the 90° tip is less prone to chipping.

[0035] S5. Finish machining of the sealing mating hole 3: Replace the special combination tool with a boring tool and finish boring the sealing mating hole 3.

[0036] S6. Machining internal threads: Use a tap to machine internal threads in the threaded connection hole 4.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for machining a double-deep-hole piston rod channel, the channel comprising two deep holes and two connector holes, each connector hole comprising a countersunk hole, a chamfer at the bottom of the countersunk hole, a sealing mating hole, a threaded connection hole, and a threaded bottom hole connected in sequence, characterized in that, A special combination tool is used to machine the joint hole. The special combination tool includes a tool body, two reamer blades, one expanding blade, one waist chamfering blade, and two tail chamfering blades. The tool body has two symmetrical chip removal grooves on both sides, which extend from the front end of the tool body to the rear end. The two reamer blades are respectively installed at the front end of the two chip removal grooves. The expanding blade is installed in the middle of one chip removal groove, and the waist chamfering blade is installed in the middle of the other chip removal groove. The two tail chamfering blades are respectively installed at the tail end of the two chip removal grooves. The tool body has two internal cooling holes, and the liquid outlet of the internal cooling holes is located near the reamer blades. The method for machining the double deep-hole piston rod channel includes the following steps: S1. Calculate the position of the deep hole: Let the diameter of the piston rod head be D1, the countersunk hole depth in the joint hole be h1, and the drilling depth of the special combination tool be h2. When D1 / 2-h1-h2≤0, the line connecting the centers of the two deep holes passes through the central axis of the piston rod. When D1 / 2-h1-h2>0, the distance e between the line connecting the centers of the two deep holes and the central axis of the piston rod is D1 / 2-h1-h2. S2. Drilling deep holes: Drill two deep holes using a deep hole drilling machine. S3, Countersunk hole of drill joint: Countersunk hole is milled on piston rod head, and the machining is completed in one feed; S4. Drilling with the special combination tool: Replace the tool with the special combination tool. High-pressure coolant is introduced into the two reamer blades through the internal cooling hole. At the same time, low-speed coolant is sprayed on the outside of the special combination tool. The two reamer blades rough machine the threaded connection hole and the threaded bottom hole. The waist chamfering blade machines the chamfer at the bottom of the sealing mating hole. The reamer blade rough machines the sealing mating hole. The tail chamfering blade machines the chamfer at the bottom of the countersunk hole. This ensures that the sharp edge at the opening of the threaded bottom hole will not extend into the sealing mating hole. S5. Finish machining of the sealing mating hole: Replace the special combination tool with a boring tool and finish bore the sealing mating hole; S6. Machining internal threads: Use a tap to machine internal threads in the threaded connection hole; The reamer insert is a square insert with a positive rake angle, and the main cutting edge of the reamer insert forms an 88° angle with the axis of the cutter body.

2. The method for machining the double deep-hole piston rod channel according to claim 1, characterized in that: The chamfer at the bottom of the countersunk hole and the chamfer at the bottom of the sealing hole are both 45°.

3. The method for machining the double deep-hole piston rod channel according to claim 2, characterized in that: In step S4, the sealing mating hole retains a machining allowance of 0.5 mm.

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