Large-length-diameter-ratio valve sleeve deep hole machining process

Abstract

The application relates to a large-length-diameter-ratio valve sleeve deep hole machining process, which is characterized by comprising the following steps: step one, rough turning; step two, gun drilling; step three, turning and milling; and step four, turning and fine boring of the inner hole; step four is operated by using a center support tool for inner hole machining; after the rough boring of the lathe, the inner hole is once fine bored to complete the hole diameter machining; the center support tool is installed on the lathe guide rail; during machining, the suspended part of the part is supported, and the clamped part and the tool holder support part are used to fix the part. The large-length-diameter-ratio valve sleeve deep hole machining process changes the previous one step into the present four steps, improves the efficiency, saves the cost and can meet the high-precision requirement.

Description

Technical Field

[0001] This invention relates to a deep hole machining process for valve sleeves with a large length-to-diameter ratio, belonging to the field of internal hole machining technology. Background Technology

[0002] Valve sleeves are important components of hydraulic breaker systems in construction machinery. Their inner bores require high precision and contain oil grooves. They work in conjunction with the valve stem or valve core to slide and control flow. One end connects to the hydraulic cylinder for operation. During production, valve sleeves require boring of their inner bore on a lathe. Deep hole machining of valve sleeves with large length-to-diameter ratios, specifically those made of 1E1122 cast iron, is characterized by: a length-to-diameter ratio greater than 4; high inner bore precision; easy deformation during bore machining; and significant machining difficulty meeting drawing requirements.

[0003] Previous machining process: Step 1: Rough turning; Step 2: Gun drilling; Step 3: Turning and milling; Step 4: Turning and boring; Step 5: Honing (rough honing and finish honing). Because the part is 336mm long and has an inner diameter of φ75.07, with a length-to-diameter ratio greater than 4, the suspended portion during conventional turning and boring causes significant tool deflection, making it impossible to guarantee the technical requirements of the inner hole. Therefore, a honing machine is needed to perform finish machining of the inner hole (honing allowance approximately 0.1-0.15mm). Furthermore, the part has a large outer diameter (Φ115mm), requiring a honing machine and honing fixtures for honing. This necessitates removing a significant amount of material and repeatedly honing the inner hole, taking approximately 40-50 minutes; the processing efficiency is slow. Additionally, the honing fixture costs approximately 10,000 RMB, and the rough and finish honing tools cost approximately 15,000 RMB, making the honing tooling and fixture costs high. The main technical specifications are as follows: total length 336±0.1mm, inner hole φ75.07±0.015mm, inner hole cylindricity 0.015, roundness 0.006, and surface roughness Ra0.4. Previous processes could not achieve these precision ranges. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art by providing a deep hole machining process for valve sleeves with a large length-to-diameter ratio, which improves efficiency, saves costs, and can achieve high precision requirements.

[0005] The technical solution adopted by this invention to solve the above problems is: a deep hole machining process for valve sleeves with a large length-to-diameter ratio, characterized by including the following steps:

[0006] Step 1: Rough turning;

[0007] Step 2: Drill holes with a gun;

[0008] Step 3: Turning and milling;

[0009] Step 4: Machining the inner hole by rough and finish boring;

[0010] Step four employs a center rest fixture for internal hole machining. The lathe performs rough boring followed by fine boring to complete the hole diameter in one pass. The center rest fixture is mounted on the lathe guide rail and supports the suspended part of the workpiece during machining, allowing the clamping point and the tool holder support to fix the workpiece together. The center rest fixture includes a base, with a connecting seat on the top of the base. Three support mechanisms are arranged evenly from front to back on the left side of the connecting seat. The middle support mechanism is fixedly connected to the connecting seat, and adjacent support mechanisms are connected by a telescopic mechanism.

[0011] The support mechanism includes a support base, on which an adsorption component and two vertically arranged support components are provided.

[0012] Preferably, the adsorption assembly includes an adsorption channel located on the left side of the support base. The adsorption channel is parallel to the left-right direction and is a blind hole. An adsorption tube is coaxially inserted into the adsorption channel. The adsorption tube is slidably and sealingly connected to the adsorption channel. The adsorption tube is locked to the support base by a first locking screw. A suction cup is located on the left side of the support base and is installed at the left end of the adsorption tube. A pressure regulating tube is vertically inserted into the top of the support base. The pressure regulating tube is connected to the adsorption tube through the adsorption channel and is equipped with a pressure regulating unit.

[0013] Preferably, the pressure regulating unit includes a lifting block, a lead screw, and a lifting tube. The lifting block is located inside the pressure regulating tube and is slidably and sealed to the pressure regulating tube. The lead screw and the lifting tube are both coaxially arranged with the pressure regulating tube. The lifting tube is fixedly installed on the top of the lifting block. The lead screw is inserted into the top of the lifting tube and is screwed to the lifting tube. A knob is installed on the top of the lead screw, which is located above the pressure regulating tube. The lead screw is connected to the pressure regulating tube through a bearing.

[0014] Preferably, the pressure regulating tube is a rectangular tube.

[0015] Preferably, the two support components are symmetrical about the adsorption tube. Each support component includes an inclined support rod that passes through a support base. The support rod is locked to the support base by a second locking screw. A roller is provided on the left side of the support base and is installed at one end of the support rod.

[0016] Preferably, the plane defined by the axes of the two support rods on the same support base is perpendicular to the front-back direction.

[0017] Preferably, the telescopic mechanism includes two telescopic components arranged symmetrically from left to right. Each telescopic component includes a fixed rod and a sleeve. The fixed rod is parallel to the front-back direction, and the sleeve is coaxially arranged with the fixed rod. In two adjacent support seats, the fixed rod is fixedly mounted on one support seat, and the sleeve is fixedly mounted on the other support seat. The fixed rod is inserted into the sleeve, and the sleeve is locked to the fixed rod by a third locking screw.

[0018] Preferably, the connecting seat includes a seat body, a sliding groove is provided on the left side of the seat body, a slider is provided in the sliding groove, the slider matches the sliding groove, the slider is fixedly provided on the right side of the support seat located in the middle, a through groove is provided on the inner wall of the right side of the sliding groove, the through groove and the sliding groove both extend to the top and bottom of the seat body, and two bolts arranged vertically are provided on the seat body, both bolts pass through the through groove, the bolts are parallel to the front and back direction, and the sliding groove clamps or releases the slider through the bolts.

[0019] Preferably, the groove is a dovetail groove.

[0020] Preferably, the slider and the support base located in the middle are integrally formed.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] This invention employs a center-support fixture for internal hole machining. Three support mechanisms support and hold the part in place, increasing the number of support points along the part's length, improving support effectiveness, preventing deformation during internal hole machining, and enhancing machining accuracy. Furthermore, by adjusting the distance between adjacent support seats, it can be applied to parts of different lengths, expanding its applicability. This invention also provides a deep hole machining process for valve sleeves with large length-to-diameter ratios, reducing the previous extra step to four steps, improving efficiency, saving costs, and achieving high precision requirements. Attached Figure Description

[0023] Figure 1 This is a perspective view of a center support fixture for internal hole machining according to the present invention;

[0024] Figure 2 This is a front view of a center support fixture for internal hole machining according to the present invention;

[0025] Figure 3 This is a top view of a center support fixture for internal hole machining according to the present invention;

[0026] Figure 4 This is a left view of a center support fixture for internal hole machining according to the present invention;

[0027] Figure 5 This is a structural diagram of the supporting mechanism;

[0028] Figure 6 A schematic diagram of the supporting components;

[0029] Figure 7 This is a sectional view of the support base;

[0030] Figure 8 This is a schematic diagram of the voltage regulating unit;

[0031] Figure 9 This is a schematic diagram of the connector.

[0032] Figure 10 These are data diagrams for five embodiments of the present invention.

[0033] The components include: base 1, connecting seat 2, seat body 21, slide groove 22, slider 23, through groove 24, bolt 25, support mechanism 3, support seat 31, adsorption assembly 32, adsorption channel 32.1, adsorption tube 32.2, first locking screw 32.3, suction cup 32.4, pressure regulating tube 32.5, pressure regulating unit 32.6, lifting block 32.61, lead screw 32.62, lifting tube 32.63, knob 32.64, bearing 32.65, support assembly 33, support rod 33.1, second locking screw 33.2, roller 33.3, telescopic mechanism 4, telescopic assembly 41, fixing rod 41.1, sleeve 41.2, third locking screw 41.3, and part 5. Detailed Implementation

[0034] like Figure 1-9 As shown, a deep hole machining process for a valve sleeve with a large length-to-diameter ratio includes the following steps:

[0035] Step 1: Rough turning

[0036] Step 2: Drill holes

[0037] Step 3: Turning and milling

[0038] Step 4: Machining the inner hole by roughing and finishing.

[0039] Step four employs a center rest fixture for internal hole machining. The lathe performs rough boring followed by finish boring in a single operation to complete the hole diameter. The center rest fixture is mounted on the lathe guide rail, supporting the suspended portion of the workpiece during machining. This ensures the workpiece is firmly fixed by the clamping point and the tool holder support, providing high rigidity and better contact between the tool and the hole wall during boring. Rough and finish boring are completed in one pass. This eliminates the need for step five in the traditional machining process.

[0040] The precision boring allowance is 0.5-0.8mm. When precision boring, it is processed together with the pneumatic probe of the inspection fixture. The larger allowance is removed in two stages. The inner hole is appropriately corrected by measuring the hole diameter with the pneumatic probe without removing the part. The boring processing time is about 30-35 minutes. The processing efficiency is improved. The center rest costs about 8,000 yuan, and the tooling cost is also reduced.

[0041] The inspection results of the machined parts after five embodiments of a deep hole machining process for a valve sleeve with a large length-to-diameter ratio are as follows: Figure 10 As shown.

[0042] The inspection results show that the improved inner hole has qualified in terms of diameter, cylindricity, roundness and roughness, which meets the requirements of the drawing, and the efficiency has also been significantly improved.

[0043] The aforementioned center support fixture for internal hole machining includes a base 1, a connecting seat 2 on the top of the base 1, and three support mechanisms 3 on the left side of the connecting seat 2. The three support mechanisms 3 are evenly arranged from front to back, with the middle support mechanism 3 fixedly connected to the connecting seat 2. Adjacent support mechanisms 3 are connected by a telescopic mechanism 4. During use, the base 1 is mounted on a machine tool, and the part 5 is mounted on the machine tool parallel to the front-back direction. The support mechanism 3 supports the part 5, and at this time, the support mechanism 3 is located to the right of the axis of the part 5. The telescopic mechanism 4 allows for adjustment of the front-back distance between adjacent support mechanisms 3, making it suitable for parts 5 of different lengths. Here, the support of the part 5 by the three support mechanisms 3 increases the number of support points in the length direction of the part 5, improves the support effect, prevents deformation during internal hole machining of the part 5, and improves machining accuracy.

[0044] The support mechanism 3 includes a support base 31, on which an adsorption component 32 and two vertically arranged support components 33 are provided. The support components 33 are used to support the part 5, and the adsorption components 32 are used to adsorb the part 5, thereby improving the support effect of the part 5.

[0045] The adsorption assembly 32 includes an adsorption channel 32.1 located on the left side of the support base 31. The adsorption channel 32.1 is parallel to the left-right direction and is a blind hole. An adsorption tube 32.2 is coaxially inserted into the adsorption channel 32.1. The adsorption tube 32.2 is slidably and sealingly connected to the adsorption channel 32.1. The adsorption tube 32.2 is locked to the support base 31 by a first locking screw 32.3. A suction cup 32.4 is located on the left side of the support base 31 and is installed at the left end of the adsorption tube 32.2. A pressure regulating tube 32.5 is vertically inserted into the top of the support base 31. The pressure regulating tube 32.5 is a rectangular tube and is connected to the adsorption tube 32.2 via the adsorption channel 32.1. The pressure regulating tube 32.5 is equipped with a pressure regulating unit 32.6. During the support of part 5, the first locking screw 32.3 is loosened, allowing the adsorption tube 32.2 to move within the adsorption channel 32.1 and the suction cup 32.4 to adhere to part 5. Then, the first locking screw 32.3 is tightened to fix the adsorption tube 32.2 to the support base 31. Next, the pressure regulating unit 32.6 reduces the air pressure in the pressure regulating tube 32.5, i.e., the air pressure in the suction cup 32.4, causing the suction cup 32.4 to adsorb part 5, improving the support effect of part 5 and preventing shaking of part 5 during processing. After part 5 is processed, the pressure regulating unit 32.6 restores the air pressure in the pressure regulating tube 32.5, allowing the suction cup 32.4 to stop adsorbing part 5.

[0046] The pressure regulating unit 32.6 includes a lifting block 32.61, a lead screw 32.62, and a lifting tube 32.63. The lifting block 32.61 is located inside the pressure regulating tube and is slidably and sealingly connected to the pressure regulating tube. Both the lead screw 32.62 and the lifting tube 32.63 are coaxially arranged with the pressure regulating tube 32.5. The lifting tube 32.63 is fixedly mounted on the top of the lifting block 32.61. The lead screw 32.62 is inserted into the top end of the lifting tube 32.63 and is screwed to the lifting tube 32.63. A screw is installed on the top end of the lead screw 32.62. Knob 32.64 is located above the pressure regulating tube. The lead screw 32.62 is connected to the pressure regulating tube through bearing 32.65. Rotating the knob 32.64 causes the lead screw 32.62 to rotate on the bearing 32.65, which in turn causes the lifting tube 32.63 to rise and fall. The rising and falling of the lifting tube 32.63 drives the lifting block 32.61 to rise and fall synchronously. When the suction cup 32.4 is attached to the part 5, the rise of the lifting block 32.61 can reduce the air pressure in the suction cup 32.4. When the lifting block 32.61 moves in the opposite direction, the air pressure in the suction cup 32.4 can be restored.

[0047] Two support components 33 are symmetrical about the adsorption tube 32.2. Each support component 33 includes an inclined support rod 33.1 that passes through a support base 31. The support rod 33.1 is locked to the support base 31 by a second locking screw 33.2. A roller 33.3 is provided on the left side of the support base 31 and is installed at one end of the support rod 33.1.

[0048] The plane defined by the axes of the two support rods 33.1 on the same support base 31 is perpendicular to the front-back direction.

[0049] When supporting part 5, loosen the second locking screw 33.2 to move the support rod 33.1, so that the support point position can be adjusted according to the diameter of part 5. After the support point position is adjusted, tighten the second screw to fix the support rod 33.1 to the support base 31. Then the roller 33.3 abuts against part 5, and the two rollers 33.3 on the same support base 31 are located above and below the axis of part 5, respectively.

[0050] The telescopic mechanism 4 includes two telescopic components 41 arranged symmetrically from left to right. Each telescopic component 41 includes a fixed rod 41.1 and a sleeve 41.2. The fixed rod 41.1 is parallel to the front-back direction, and the sleeve 41.2 is coaxially arranged with the fixed rod 41.1. In two adjacent support seats 31, the fixed rod 41.1 is fixedly mounted on one support seat 31, and the sleeve 41.2 is fixedly mounted on the other support seat 31. The fixed rod 41.1 is inserted into the sleeve 41.2, and the sleeve 41.2 is locked to the fixed rod 41.1 by a third locking screw 41.3. When it is necessary to adjust the distance between two adjacent support seats 31, the third locking screw 41.3 is loosened, allowing the sleeve 41.2 to move coaxially on the fixed rod 41.1, thus achieving distance adjustment. After adjustment, the third locking screw 41.3 is tightened to fix the fixed rod 41.1 and the sleeve 41.2 relatively.

[0051] The connecting seat 2 includes a seat body 21. A groove 22 is provided on the left side of the seat body 21, and a slider 23 is disposed within the groove 22. The slider 23 matches the groove 22 and is fixedly disposed on the right side of the central support seat 31. The slider 23 and the central support seat 31 are integrally formed. A through groove 24 is provided on the inner wall of the right side of the groove 22. Both the through groove 24 and the groove 22 extend to the top and bottom of the seat body 21. Two bolts 25 are arranged vertically on the seat body 21. All 5 parts pass through the through groove 24. The bolt 25 is parallel to the front and back direction. The bolt 25 is used to clamp or loosen the slider 23 in the slide groove 22. The slide groove 22 is a dovetail groove. When the bolt 25 is loosened, the slider 23 moves up and down in the slide groove 22. This allows the support base 31 to adjust its position according to the height of the part 5. After the position is adjusted, the bolt 25 is tightened to reduce the distance between the front and back of the through groove 24 and to clamp the slider 23 in the slide groove 22. This keeps the slider 23 and the base 21 in a relatively static position, thus fixing the support base 31.

[0052] In addition to the above embodiments, the present invention also includes other embodiments. All technical solutions formed by equivalent transformation or equivalent substitution should fall within the protection scope of the claims of the present invention.

Claims

1. A deep hole machining process for valve sleeves with large length-to-diameter ratio, characterized in that... Includes the following steps: Step 1: Rough turning; Step 2: Drill holes with a gun; Step 3: Turning and milling; Step 4: Machining the inner hole by rough and finish boring; Step four uses a center frame fixture for internal hole machining. The lathe rough boring and then fine boring are completed in one go to complete the hole diameter. The center frame fixture is installed on the lathe guide rail. During machining, it supports the suspended part of the part and fixes the part together with the clamping point and the tool holder support point. The center frame fixture includes a base (1). A connecting seat (2) is provided on the top of the base (1). Three support mechanisms (3) are provided on the left side of the connecting seat (2). The three support mechanisms (3) are evenly arranged from front to back. The middle support mechanism (3) is fixedly connected to the connecting seat (2). The two adjacent support mechanisms (3) are connected by a telescopic mechanism (4). The support mechanism (3) includes a support base (31), on which an adsorption component (32) and two vertically arranged support components (33) are provided. The adsorption assembly (32) includes an adsorption channel (32.1) disposed on the left side of the support base (31). The adsorption channel (32.1) is parallel to the left and right direction and is a blind hole. An adsorption tube (32.2) is coaxially inserted into the adsorption channel (32.1). The adsorption tube (32.2) is slidably and sealed to the adsorption channel (32.1). The adsorption tube (32.2) is locked to the support base (31) by a first locking screw (32.3). A suction cup (32.4) is disposed on the left side of the support base (31). The suction cup (32.4) is installed at the left end of the adsorption tube (32.2). A pressure regulating tube (32.5) is vertically inserted into the top of the support base (31). The pressure regulating tube (32.5) is connected to the adsorption tube (32.2) through the adsorption channel (32.1). A pressure regulating unit (32.6) is disposed on the pressure regulating tube (32.5). The pressure regulating unit (32.6) includes a lifting block (32.61), a lead screw (32.62), and a lifting tube (32.63). The lifting block (32.61) is located inside the pressure regulating tube and is slidably and sealed to the pressure regulating tube. The lead screw (32.62) and the lifting tube (32.63) are both coaxially arranged with the pressure regulating tube (32.5). The lifting tube (32.63) is fixedly installed on the top of the lifting block (32.61). The lead screw (32.62) is inserted into the top of the lifting tube (32.63) and is screwed to the lifting tube (32.63). A knob (32.64) is installed on the top of the lead screw (32.62) and is located above the pressure regulating tube. The lead screw (32.62) is connected to the pressure regulating tube through a bearing (32.65).

2. The deep hole machining process for a valve sleeve with a large length-to-diameter ratio according to claim 1, characterized in that, Its features are: The pressure regulating tube (32.5) is a rectangular tube.

3. The deep hole machining process for a valve sleeve with a large length-to-diameter ratio according to claim 1, characterized in that: Two support components (33) are symmetrical about the adsorption tube (32.2). Each support component (33) includes an inclined support rod (33.1) that passes through a support base (31). The support rod (33.1) is locked to the support base (31) by a second locking screw (33.2). A roller (33.3) is provided on the left side of the support base (31) and is installed at one end of the support rod (33.1).

4. The deep hole machining process for a valve sleeve with a large length-to-diameter ratio according to claim 3, characterized in that, Its features are: The plane defined by the axes of the two support rods (33.1) on the same support base (31) is perpendicular to the front-back direction.

5. The deep hole machining process for a valve sleeve with a large length-to-diameter ratio according to claim 1, characterized in that: The telescopic mechanism (4) includes two telescopic components (41) arranged symmetrically on the left and right. Each telescopic component (41) includes a fixed rod (41.1) and a sleeve (41.2). The fixed rod (41.1) is parallel to the front-back direction. The sleeve (41.2) is coaxially arranged with the fixed rod (41.1). In two adjacent support seats (31), the fixed rod (41.1) is fixedly installed on one of the support seats (31), and the sleeve (41.2) is fixedly installed on the other support seat (31). The fixed rod (41.1) is inserted into the sleeve (41.2), and the sleeve (41.2) is locked to the fixed rod (41.1) by a third locking screw (41.3).

6. The deep hole machining process for a valve sleeve with a large length-to-diameter ratio according to claim 1, characterized in that: The connecting seat (2) includes a seat body (21). A sliding groove (22) is provided on the left side of the seat body (21). A slider (23) is provided in the sliding groove (22). The slider (23) matches the sliding groove (22). The slider (23) is fixedly provided on the right side of the support seat (31) located in the middle. A through groove (24) is provided on the inner wall of the right side of the sliding groove (22). The through groove (24) and the sliding groove (22) both extend to the top and bottom of the seat body (21). Two bolts (25) are arranged vertically on the seat body (21). Both bolts (25) pass through the through groove (24). The bolts (25) are parallel to the front and back direction. The sliding groove (22) clamps or releases the slider (23) through the bolts (25).

7. The deep hole machining process for a valve sleeve with a large length-to-diameter ratio according to claim 6, characterized in that, Its features are: The groove (22) is a dovetail groove.

8. The deep hole machining process for a valve sleeve with a large length-to-diameter ratio according to claim 6, characterized in that, Its features are: The slider (23) and the support base (31) located in the middle are integrally formed.

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