Half-bridge multi-layer composite tool and multi-piece multi-procedure machining method

Abstract

According to the half-bridge multi-layer composite tool and the multi-piece multi-process machining method, the tool is of an integral structure formed by welding a base, a vertical plate, a vertical rib plate and a top plate, the base is provided with positioning pins and blind rivet holes, and four-position quick replacement can be achieved; the upper-layer machining station and the lower-layer machining station are each provided with four clamping assemblies of a rotary pressing plate and a quick-release nut, and two blanks are clamped at a time; a locating pin supporting block and a threaded hole supporting block are arranged at the front and back two-sequence machining position, two semi-finished products can be hung, and the differential mechanism installation face faces upwards. During machining, stepped progressive cutting is adopted, upper and lower cutting force peak values are staggered, and resonance is avoided; the roundness and the location degree of the bearing hole are measured on line, and automatic cutter compensation is conducted when the bearing hole is out of tolerance And after the clamp is loosened, part replacement is not waited. Four pieces can be clamped at a time, the shift yield is obviously improved, model changing is convenient, the yield is obviously improved, one set of tool is suitable for various flange reference circles, clamp storage is reduced, the universality is high, and the adaptation cost caused by model difference is reduced.

Description

Technical Field

[0001] This invention relates to the field of machining technology for drive half-axles of agricultural machinery, commercial vehicles and engineering machinery. Specifically, it relates to a multi-layer composite tooling and its machining method that can realize multi-part simultaneous and multi-process completion in one clamping. It is applicable to the clamping, milling, drilling, boring and other multi-process machining of drive half-axles (including key structures such as flanges, journals, differential mounting surfaces, and steering knuckle mounting ears) of heavy machinery such as agricultural machinery, large forklifts and engineering cranes. Background Technology

[0002] The drive half-axle requires milling, drilling, and boring of multiple features, including flanges, journals, differential mounting surfaces, and steering knuckle lugs. Existing tooling has the following prominent problems: 1. Efficiency bottleneck: Existing tooling is mostly a single-layer double-station or single-station + double-table structure. Horizontal machining centers can process one product at a time, while the other worktable waits for processing after the product is clamped. This is not suitable for the mass production needs of the drive half-bridge, resulting in low efficiency and inability to meet the needs of large-volume rapid delivery. This leads to delivery delays, increased risk of customer complaints, and is detrimental to business operations.

[0003] 2. Poor adaptability: Different models of drive half-bridges have large differences in shape, flange pitch circle and positioning surface. Changing models requires replacing the entire set of fixtures, and the debugging time is as long as 2 to 4 hours. The overall efficiency (OEE) of the equipment decreases by 15 to 20%. Enterprises need to keep more than 20 sets of fixtures, which results in high capital occupation and complicated warehouse management.

[0004] 3. Defects in multi-layer coordination: Some multi-layer tooling has insufficient rigidity in the upper layer, uneven clamping force between the upper and lower layers, chatter during cutting, out-of-tolerance roundness and position, low yield, and high rework costs; moreover, the upper station has obvious vibration and chatter errors, making it difficult to meet the requirements of high-precision mass production.

[0005] Therefore, there is an urgent need in the market for a semi-bridge multi-layer composite tooling that can clamp multiple parts at once, has balanced rigidity between upper and lower layers, allows for rapid changeover within 30 minutes, and has a high yield rate, in order to solve the problems of efficiency, quality, versatility, and cost. Summary of the Invention

[0006] The technical problem this invention aims to solve is to provide a multi-layer composite tooling for half-bridges and a multi-part, multi-process machining method. This method enables the simultaneous clamping of two single-stage or two double-stage half-bridges, reducing clamping waiting time and clamping difficulty. The vertical plate is equipped with reinforcing ribs to increase the structural rigidity of the upper workstation, reducing machining vibration and improving yield. This invention is adaptable to similar products, reduces tooling changeover and debugging time, increases overall equipment efficiency, and reduces the investment cost of tooling fixtures.

[0007] The technical solution adopted by this invention to solve the technical problem is as follows: A semi-bridge multi-layer composite tooling includes a base, a main support unit, an upper machining station unit, a lower machining station unit, and a secondary machining station unit. The bottom surface of the base is provided with a worktable positioning pin and clamping tie holes for engaging with the machine tool worktable pin holes to achieve overall positioning and fastening of the tooling. The main support unit consists of a vertical plate, vertical stiffeners, and a top plate. The vertical plate is vertically welded to the base, the vertical stiffeners are welded to the right side of the vertical plate, and the top plate is welded to the top of the vertical plate, forming a closed anti-torsion box structure. The upper machining station unit is located in the upper half of the vertical plate and is provided with a vertical support point and a horizontal apex for pre-positioning the blank. It is also equipped with horizontal set screws and a rotating pressure plate with corresponding quick-release mechanism. The four sets of clamping assemblies, consisting of nuts, are used for horizontal and vertical clamping of the blank. The lower processing unit is located in the lower half of the vertical plate and is equipped with vertical support points, horizontal apex, horizontal set screws, and four sets of clamping assemblies consisting of rotating pressure plates and corresponding quick-release nuts, which are symmetrical to the upper processing unit. These are used for pre-positioning and clamping of the second blank. The second-order processing unit is located at the front and rear ends of the base. Each end is equipped with a support block with a positioning pin for angular positioning of the processed flange, and a support block with a threaded hole. The support block cooperates with the hanging bolt to form a hanging vertical fixation, so that the mounting surface of the first-order semi-finished differential faces upward. The vertical plate, vertical stiffener plate, top plate, and base are integrally welded structures.

[0008] Furthermore, the rotating pressure plate and the quick-release nut work together to enable the pressure plate to be tightened or loosened quickly.

[0009] Furthermore, the worktable positioning pin is coupled with the machine tool worktable pin hole to achieve repeated positioning of the tooling.

[0010] Furthermore, the support block with threaded holes is used to cooperate with bolts to vertically fix the first-order semi-finished flange in a hanging manner.

[0011] Furthermore, the vertical plates and the vertical stiffeners, as well as the vertical plates and the top plate, are all welded together to form an integral torsional frame.

[0012] A multi-part, multi-process machining method using the aforementioned half-bridge multi-layer composite tooling includes the following steps: S1. Select the corresponding processing program according to the type of blank or semi-finished product; S2. Hoist the base onto the machine tool worktable, so that the worktable positioning pin falls into the pin hole, and complete the tooling positioning; S3, four pieces can be clamped at once: (1) Place the first blank in the upper processing position, pre-position it using the vertical support point and the horizontal vertex, and clamp it by rotating the pressure plate, quick release nut and set screw; (2) Place the second blank in the lower processing position and clamp it in the same way; (3) Hang two first-order semi-finished products at the second-order processing position, align the flange holes with the positioning pins, and screw the bolts into the threaded holes of the support block to form a hanging vertical fixation; S4, stepped progressive cutting: first, mill the lower blank and drill holes, then mill the upper blank and drill holes, and finally bore and groove the two semi-finished products in sequence. The cutting force peaks of the upper and lower layers are staggered in the time domain to avoid resonance. S5. Use the side head of the machine tool to inspect the roundness and position of the bearing holes in the semi-finished product, and automatically compensate for deviations. S6. After processing, quickly loosen the pressure plate and bolts, lift out the finished product and immediately install the new part to achieve a zero-wait cycle.

[0013] Furthermore, in step S4, the stepped progressive cutting adopts a timing control strategy of cutting the lower layer first and then the upper layer, and coarsening first and then finishing, to avoid resonance caused by cutting the upper and lower layers simultaneously.

[0014] Furthermore, in step S5, the roundness and positional accuracy results obtained from the machine tool side inspection are fed back to the CNC system in real time. If the deviation exceeds the tolerance, the tool length compensation macro program is automatically called for correction.

[0015] Furthermore, in step S3, tightening the hanging bolts prevents micro-vibration of the flange surface during the second-stage machining process.

[0016] Furthermore, in step S2, after the replacement is completed, the clearance between the worktable positioning pin and the pin hole is verified by rotating the fourth axis of the machine tool to ensure repeatability positioning accuracy.

[0017] The positive and beneficial effects of this invention are as follows: 1. Increased production capacity: It can clamp four pieces at a time (two blanks + two semi-finished products), significantly increasing the output per shift, meeting the demand for large-volume delivery, and significantly alleviating the shortage of production capacity.

[0018] 2. Quality Improvement: The closed anti-torsion box structure and stepped progressive cutting are adopted, and the peak cutting forces of the upper and lower layers are staggered, which effectively reduces chatter, significantly improves machining accuracy and surface quality, increases the yield rate to ≥98%, and greatly reduces rework.

[0019] 3. Quick model changeover: The combination of positioning pins and movable support blocks allows for the changeover of different flange pitch circles in 30 minutes. Model switching is convenient, and the commissioning time is shortened from 2-4 hours to ≤30 minutes. Equipment downtime is significantly reduced, and the overall operating efficiency of the equipment is improved by more than 15%.

[0020] 4. Cost savings: One set of tooling can be adapted to multiple flange pitch circles, reducing the number of fixtures in stock by 50%, reducing capital occupation, and correspondingly reducing warehousing and management costs.

[0021] 5. Wide range of applications: The tooling structure can be extended to similar parts such as front axles and steering knuckles without additional design costs. It has strong versatility and further reduces the adaptation costs caused by model differences. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention when four pieces are clamped at once; Figure 3 for Figure 2 Side view (direction and) Figure 1 correspond); Figure 4 for Figure 3 Top view.

[0023] In the diagram, 1--vertical plate, 2--top plate, 3--lifting eye nut, 4--vertical stiffener plate, 5--base, 6--first support block, 7--second support block, 8--first workbench bolt, 9--workbench positioning pin, 10--second workbench bolt, 11--first pressure plate, 12--first pressure plate nut, 13--pressure plate base, 14--first set screw, 15--second pressure plate, 16--second pressure plate nut, 17--second set screw, 18--third pressure plate, 19--third pressure plate nut, 20--first support point, 21--fourth pressure plate, 22--fourth set screw, 23--fourth pressure plate nut, 24--fifth pressure plate, 25--fifth pressure plate nut, 26--second support point, 27--second-sequence front half-bridge, 28--second-sequence bolt one, 29--second-sequence bolt two, 30--sixth pressure plate, 31-- - Sixth pressure plate nut, 32--First sequence lower blank, 33--Seventh pressure plate, 34--Seventh pressure plate nut, 35--Seventh set screw, 36--Eighth pressure plate, 37--Eighth pressure plate nut, 38--Third support point, 39--First sequence upper blank, 40--First vertex, 41--Second vertex, 42--Third vertex, 43--Fourth vertex, 44--Fifth vertex, 45--Fourth support point, 46--Sixth vertex, 47--Second sequence bolt three, 48--First locating pin support block, 49--Second sequence bolt four, 50--Second locating pin support block, 51--Third support block, 52--Third locating pin support block, 53--Fourth support block. Detailed Implementation

[0024] The invention will now be further explained and described with reference to the accompanying drawings: See Figures 1-4A semi-bridge multi-layer composite tooling includes a base 5, a main support unit, an upper machining unit, a lower machining unit, and a secondary machining unit. The bottom surface of the base 5 is provided with a worktable positioning pin 9 and clamping tie holes for engaging with the machine tool worktable pin holes to achieve overall positioning and fastening of the tooling. The main support unit consists of a vertical plate 1, vertical stiffeners 4, and a top plate 2. The vertical plate 1 is vertically welded to the base 5, the vertical stiffeners 4 are welded to the right side of the vertical plate 1, and the top plate 2 is welded to the top of the vertical plate 1, forming a closed anti-torsion box structure. The upper machining unit is located in the upper half of the vertical plate 1 and is provided with vertical support points 38 and 20 and horizontal vertices 40, 41, and 42 for pre-positioning of the blank. It is also equipped with horizontal set screws 14 and 17 and four sets of clamping assemblies consisting of rotating pressure plates 11, 15, 18, and 36 and corresponding quick-release nuts 12, 16, 19, and 37 for... The blank is clamped horizontally and vertically; the lower processing unit is located in the lower half of the vertical plate 1, and is equipped with vertical support points 26, 45, horizontal vertices 43, 44, 46, horizontal set screws 22, 35, and four sets of clamping components consisting of rotating pressure plates 21, 24, 30, 33 and corresponding quick-release nuts 23, 25, 31, 34, which are symmetrical to the upper processing unit, for the pre-positioning and clamping of the second blank; the second processing unit is located at the front and rear ends of the base 5, and each end is equipped with support blocks 48, 50, 52 with positioning pins for the angle positioning of the processed flange, and is equipped with support blocks 6, 7, 51, 53 with threaded holes. The support blocks cooperate with the hanging bolts 28, 29, 47, 49 to form a hanging vertical fixation, so that the mounting surface of the first semi-finished differential faces upward; the vertical plate 1, vertical stiffener plate 4, top plate 2 and base 5 are integrally welded into a single structure.

[0025] The rotating pressure plate and the quick-release nut work together to achieve rapid tightening and loosening of the pressure plate.

[0026] The worktable positioning pin 9 is coupled with the pin hole of the machine tool worktable to achieve repeated positioning of the tooling.

[0027] Support blocks 6, 7, 51, and 53 with threaded holes are used to mate with bolts for vertical hanging fixation of the first-order semi-finished flange.

[0028] The vertical plate 1 and the vertical stiffening plate 4, as well as the vertical plate 1 and the top plate 2, are all welded together to form an overall anti-torsional frame.

[0029] A multi-part, multi-process machining method using the above-mentioned semi-bridge multi-layer composite tooling includes the following steps: S1. Select the corresponding processing program according to the type of blank or semi-finished product; S2. Hoist the base 5 onto the machine tool worktable, so that the worktable positioning pin 9 falls into the pin hole, and complete the tooling positioning. S3, four pieces can be clamped at once: (1) Place the first blank in the upper processing position, pre-position it using the vertical support point and the horizontal vertex, and clamp it by rotating the pressure plate, quick release nut and set screw; (2) Place the second blank in the lower processing position and clamp it in the same way; (3) Hang two first-order semi-finished products at the second-order processing position, align the flange holes with the positioning pins, and screw bolts 28, 29, 47, and 49 into the threaded holes of the support block to form a hanging vertical fixation; S4, stepped progressive cutting: first, mill the lower blank and drill holes, then mill the upper blank and drill holes, and finally bore and groove the two semi-finished products in sequence. The cutting force peaks of the upper and lower layers are staggered in the time domain to avoid resonance. S5. Use the side head of the machine tool to inspect the roundness and position of the bearing holes in the semi-finished product, and automatically compensate for deviations. S6. After processing, quickly loosen the pressure plate and bolts, lift out the finished product and immediately install the new part to achieve a zero-wait cycle.

[0030] In step S4, the stepped progressive cutting adopts a timing control strategy of cutting the lower layer first and then the upper layer, and coarse first and then fine, to avoid resonance caused by cutting the upper and lower layers simultaneously.

[0031] In step S5, the roundness and positional accuracy results obtained from the machine tool side inspection are fed back to the CNC system in real time. If the deviation is out of tolerance, the tool length compensation macro program is automatically called to correct it.

[0032] In step S3, tightening the hanging bolts 28, 29, 47, and 49 can prevent micro-vibration of the flange surface during the second-stage machining.

[0033] In step S2, after the replacement is completed, the clearance between the worktable positioning pin 9 and the pin hole is verified by rotating the fourth axis of the machine tool to ensure repeatability positioning accuracy.

[0034] Example 1: Agricultural machinery 4WD rear axle half-bridge (φ200 flange): A. Fixture positioning: Insert the worktable positioning pin 9 on the bottom surface of the base 5 into the corresponding pin hole of the machine tool worktable, use a magnetic base to check the level of the edge of the base plate, and then tighten the worktable bolts 8 and 10 to complete the overall positioning of the fixture. B. Four pieces can be clamped at once: (1) Upper processing station: The 40Cr forging billet is hoisted in, with the first support point 20 and the third support point 38 bearing the weight; the first vertex 40, the second vertex 41, and the third vertex 42 complete the front and rear pre-positioning; the first set screw 14 and the second set screw 17 are pushed and tightened laterally; the first pressure plate 11, the second pressure plate 15, the third pressure plate 18, and the eighth pressure plate 36 are pressed in sequence, and the quick-release nuts 12, 16, 19, and 37 are manually pre-tightened, and then the torque wrench is used to tighten them all at once to form a horizontal and vertical clamping; (2) Lower processing position: The second blank clamping is completed in the same way; (3) Second-order front half bridge 27: The first-order semi-finished product with one end already processed is hoisted into the front: the flange face is close to the positioning pin support block 50, 52, and the bolts 28, 29 pass through the flange hole and are screwed into the threaded holes of the support block 6, 7 to form a hanging vertical fixation, with the differential mounting surface facing upward. (4) Rear half bridge of the second sequence: hoisted into the rear in the same way, and bolts 47 and 49 are screwed into the fourth support block 53 to form a hanging fixation; The entire clamping process takes ≤6 minutes, resulting in a mixed-line layout of "two blanks + two semi-finished products".

[0035] C. Stepped progressive cutting: First, the lower layer is milled and drilled; then the upper layer is milled and drilled; finally, the two semi-finished products are bored and grooved in sequence. The CNC program makes the peak cutting forces of the upper and lower layers staggered in the time domain to avoid resonance.

[0036] D. Online measurement and compensation: The machine tool side head is immediately inspected after precision boring: if the roundness and positional accuracy are out of tolerance, the tool length compensation value is automatically adjusted to achieve closed-loop correction.

[0037] E. Disassembly and Cycle: Loosen all quick-release nuts and bolts, lift the pressure plate in 3 seconds, and hoist out the finished product; immediately load in new blanks and semi-finished products, and enter the next cycle, achieving zero waiting time.

[0038] Example 2: Forklift drive half-axle (φ240 flange): Only the locating pin support blocks at positions 48, 50, and 52 were replaced and slid along the T-slot to the φ240mm pitch circle, and the changeover was completed in 28 minutes; the remaining clamping, cutting, and measurement steps were the same as in Example 1. 500 pieces were produced continuously to verify the universality of the tooling for the six types of flange pitch circles.

[0039] Through Examples 1 and 2, it can be concluded that: after adopting the semi-bridge multi-layer composite tooling and multi-part multi-process processing method of the present invention, the overtime output of a single horizontal machine is significantly improved, chatter is significantly reduced, the yield rate is steadily improved, the changeover time is greatly shortened, the capital occupation is reduced, and the versatility is relatively high.

Claims

1. A semi-bridge multi-layer composite tooling, characterized in that: It includes a base (5), a main support unit, an upper processing unit, a lower processing unit, and a secondary processing unit; the base (5) The bottom surface is provided with a worktable positioning pin (9) and a clamping pull pin hole, which are used to cooperate with the worktable pin hole of the machine tool to realize the overall positioning and fastening of the tooling; the main support unit is composed of a vertical plate (1), a vertical stiffener plate (4) and a top plate (2). The vertical plate (1) is vertically welded to the base (5), the vertical stiffener plate (4) is welded to the right side of the vertical plate (1), and the top plate (2) is welded to the top of the vertical plate (1). The three form a closed anti-torsion box structure; the upper processing unit is located in the upper half of the vertical plate (1), and is provided with vertical support points (38, 20) and horizontal apexes (40, 41, 42) for pre-positioning of the blank, and is equipped with horizontal set screws (14, 17) and four sets of clamping components composed of rotating pressure plates (11, 15, 18, 36) and corresponding quick-release nuts (12, 16, 19, 37) for clamping the blank horizontally and vertically; the lower processing unit is located in the vertical plate (1) The lower half is provided with vertical support points (26, 45), horizontal apex (43, 44, 46), horizontal set screws (22, 35) symmetrical to the upper processing unit, and four sets of clamping components consisting of rotating pressure plates (21, 24, 30, 33) and corresponding quick-release nuts (23, 25, 31, 34) for pre-positioning and clamping of the second blank; the second processing unit is located at the front and rear ends of the base (5), and each end is provided with a support block (48, 50, 52) with positioning pin for angular positioning of the processed flange, and a support block (6, 7, 51, 53) with threaded holes. The support block and the hanging bolt (28, 29, 47, 49) cooperate to form a hanging vertical fixation so that the mounting surface of the first semi-finished differential faces upward; the vertical plate (1), vertical rib plate (4), top plate (2) and base (5) are integrally welded structures.

2. The semi-bridge multi-layer composite tooling according to claim 1, characterized in that: The rotating pressure plate and the quick-release nut work together to enable the pressure plate to be tightened or loosened quickly.

3. The semi-bridge multi-layer composite tooling according to claim 1 or 2, characterized in that: The worktable positioning pin (9) is coupled with the machine tool worktable pin hole to achieve repeated positioning of the tooling.

4. The semi-bridge multi-layer composite tooling according to any one of claims 1 to 3, characterized in that: The threaded support blocks (6, 7, 51, 53) are used in conjunction with bolts to vertically fix the first-order semi-finished flange in a hanging manner.

5. The semi-bridge multi-layer composite tooling according to any one of claims 1 to 4, characterized in that: The vertical plate (1) and the vertical stiffener plate (4), as well as the vertical plate (1) and the top plate (2), are all welded together to form an integral anti-torsional frame.

6. A method for multi-part, multi-process machining using the semi-bridge multi-layer composite tooling according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Select the corresponding processing program according to the type of blank or semi-finished product; S2. Hoist the base (5) to the machine tool worktable, so that the worktable positioning pin (9) falls into the pin hole and the tooling positioning is completed. S3, four pieces can be clamped at once: (1) Place the first blank in the upper processing position, pre-position it using the vertical support point and the horizontal vertex, and clamp it by rotating the pressure plate, quick release nut and set screw; (2) Place the second blank in the lower processing position and clamp it in the same way; (3) Hang two first-order semi-finished products at the second-order processing position, align the flange holes with the positioning pins, and screw the bolts (28, 29, 47, 49) into the threaded holes of the support block to form a hanging vertical fixation; S4, stepped progressive cutting: first, mill the lower blank and drill holes, then mill the upper blank and drill holes, and finally bore and groove the two semi-finished products in sequence. The cutting force peaks of the upper and lower layers are staggered in the time domain to avoid resonance. S5. Use the side head of the machine tool to inspect the roundness and position of the bearing holes in the semi-finished product, and automatically compensate for deviations. S6. After processing, quickly loosen the pressure plate and bolts, lift out the finished product and immediately install the new part to achieve a zero-wait cycle.

7. The processing method according to claim 6, characterized in that: In step S4, the stepped progressive cutting adopts a timing control strategy of cutting the lower layer first and then the upper layer, and coarse first and then fine, to avoid resonance caused by cutting the upper and lower layers simultaneously.

8. The processing method according to claim 6 or 7, characterized in that: In step S5, the roundness and positional accuracy results obtained from the machine tool side inspection are fed back to the CNC system in real time. If the deviation is out of tolerance, the tool length compensation macro program is automatically called to correct it.

9. The processing method according to any one of claims 6 to 8, characterized in that: Tightening the hanging bolts (28, 29, 47, 49) in step S3 can prevent micro-vibration of the flange surface during the second-stage machining.

10. The processing method according to any one of claims 6-9, characterized in that: After the replacement is completed in step S2, the gap between the worktable positioning pin (9) and the pin hole is verified by rotating the fourth axis of the machine tool to ensure repeatability positioning accuracy.

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