Machine tool for machining bimetal linings through rigid reamer

Abstract

The machine tool comprises a base, a main shaft, a cutter bar locking screw rod, the rigid reamer, a clamp, a tailstock and an air cylinder, a movable center is arranged at the end, close to the clamp, of the tailstock, and the end, away from the rigid reamer, of the cutter bar locking screw rod is connected with a driving mechanism through a transmission piece; the lower end of the clamp is connected with the base in a sliding mode, and a positioning hole is formed in the position, corresponding to a workpiece, of the clamp. According to the machine tool for machining the bimetal lining through the rigid reamer, in the machining process, the rigid reamer is connected with the main shaft through the cutter bar locking screw rod, so that the rigid reamer only rotates on the power source, a workpiece has radial micro-compensation floating in the axial movement process, good follow-up movement is kept, the movement inertia of the workpiece is relieved, and the machining precision of the bimetal lining is improved. And microscopic size change caused by radial movement of the relative rigid reamer is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bimetallic bushing processing, in particular to a machine tool for processing bimetallic bushings with a rigid reamer. Background Art

[0002] Bushings are a key component widely used in the industrial and mechanical fields. Their main features include high load-bearing capacity, low friction coefficient, wear resistance and self-lubricating properties. Bimetallic bushings are widely used in industrial equipment, automotive parts, etc., especially in scenarios that require high load-bearing capacity and wear resistance. Bushings are divided into full copper alloy bushings and bimetallic bushings. Bimetallic bushings are changed from steel backing to copper alloy bushings based on the size of full copper alloy bushings. Compared with the original full copper alloy bushings, the cost reduction is relatively large, so they are widely used in mechanical equipment, industrial equipment, automobiles and other industries. However, because bimetallic bushings are composed of two metals, take the bimetallic bushing of a certain automobile steering knuckle as an example: the outer steel back material is 08AL cold-rolled plate, hardness HV110-140; thickness is 1.5mm; copper layer grade s WFQSn6-6-3, composition Cu82-88%, Sn5-7%, Pb2-4%, hardness HV80-110; thickness is 0.5mm. The coaxiality requirement of the two bimetallic bushings after processing is Ф0.03mm, while the effective thickness of the copper layer is only 0.5mm, which also has higher requirements for processing, because the structure of the parts for installing the bushings is relatively long and is very sensitive to coaxiality errors. Whether it is the axis error between the tool and the bimetallic bushing, or the position offset of the workpiece after the part is installed on the fixture, as long as there is an error of 0.077°, the steel back of the bimetallic bushing will be processed, causing the bimetallic bushing to fail and be scrapped. Moreover, this position is in a local position inside the part hole and is very difficult to find. If this overcutting phenomenon is not found, the parts will be assembled and put into use, which will cause sintering failure of related connecting parts. If this happens on important equipment, it may even cause a major accident in which important parts are scrapped.

[0003] The bimetallic bushing processing methods in the industry are roughly divided into 7 types, namely boring tool processing, rolling processing, extrusion processing, broaching tool processing, push tool processing, floating reamer floating workpiece processing, floating reamer fixed workpiece processing, etc., each has its own advantages and disadvantages; the specific analysis is as follows:

[0004] 1) Boring tool processing has high requirements for fixtures and low processing costs. However, when the accuracy of the fixture positioning parts is poor and the coaxiality of the two power shafts of the equipment is poor, cutting deviations will occur, causing the tool to cut the steel back, the copper sleeve parts to be scrapped, and rework and other wastes. In addition, the adjustment of equipment and fixtures requires a considerable level of skills to safely achieve batch processing, and the scrap rate is very high.

[0005] 2) Roll forming: The workpiece is installed on the equipment for rotary motion, or the roll forming tool rotates. The roll forming tool is a roll forming head with steel balls or rollers, which is used to roll form the copper sleeve of the part. The advantage is that the copper sleeve can be rolled more densely and has better wear resistance, but it has very high requirements for the allowance and cannot guarantee good dimensional accuracy.

[0006] 3) Extrusion processing: The workpiece does not move, and the tool makes rotary and feeding motions. It has high efficiency and the effect of roll forming, but there is also a phenomenon that when the allowance is large, the oil guiding groove of the bimetallic copper bushing will be closed, resulting in scrapping of the part.

[0007] 4) Broaching: The advantage is that the dimensions are stable, but the equipment structure is complex and requires a manual or mechanical tool changing device; and the cutting force is in the axial direction. When the tool wears and the cutting force increases, or when the interference fit of the bimetallic bushing is small, the copper sleeve may be pulled out of the workpiece, resulting in failure; the equipment needs a tool changing device; for the convenience of manufacturing and reducing the tool cost, the tool is generally made of high-speed steel, which is not wear-resistant and has large dimensional changes.

[0008] 5) Push broaching: The advantage is that the dimensions are stable, but the equipment structure is complex and requires a manual or mechanical tool changing device; and the cutting force is in the axial direction. When the tool wears and the cutting force increases, or when the interference fit of the bimetallic bushing is small, the copper sleeve may be pushed out of the workpiece, resulting in failure; the equipment needs a tool changing device; for the convenience of manufacturing and reducing the tool cost, the tool is generally made of high-speed steel, which is not wear-resistant and has large dimensional changes.

[0009] 6) Floating reamer floating workpiece processing: Both the workpiece and the tool are floating, belonging to dynamic processing. The tool shakes inside the workpiece, and the workpiece also shakes, which affects the dimensional stability; manually guiding the tool weighing 2500 grams to align with the workpiece hole has safety risks.

[0010] 7) Floating reamer fixed workpiece processing: The tool is in a floating state and is in dynamic processing. The tool shakes inside the workpiece. When the floating device inside the floating tool holder is blocked by copper chips, resulting in floating failure, it affects the dimensional stability; and the floating tool holder is expensive.

[0011] In summary, the existing processing methods of bimetallic bushings in the industry have many problems such as complex equipment, difficult dimension guarantee, difficult dimension guarantee, and potential safety hazards. Summary of the Invention

[0012] The purpose of the present invention is to provide a machine tool for processing bimetallic bushings with a rigid reamer to solve the problems of complex equipment and difficult dimension guarantee existing in the existing processing methods of bimetallic bushings.

[0013] The present invention provides a machine tool for processing a bimetallic bushing with a rigid reamer, which includes a base, a main shaft provided on one side of the upper end of the base, a tool shank locking screw provided in the main shaft, a rigid reamer connected to the tool shank locking screw, a fixture provided on the right side of the rigid reamer, a tailstock provided on the right side of the fixture, and a cylinder connected to the tailstock. An active center is provided at one end of the tailstock close to the fixture. One end of the tool shank locking screw away from the rigid reamer is connected to a driving mechanism through a transmission member. The lower end of the fixture is slidably connected to the base, and a positioning hole is provided at a position corresponding to the workpiece.

[0014] Further, the lower end of the fixture is connected to the base through a slide table.

[0015] Further, an air inlet pipe for the tailstock and an air exhaust pipe for the tailstock communicating with the pipe body are provided on the pipe body of the cylinder.

[0016] Further, the driving mechanism is a motor, and the transmission member includes a transmission rod and steering transmission gears at both ends of the transmission rod.

[0017] Further, the rigid reamer includes a front guiding portion, a cutting and extruding portion, a rear guiding portion, and a Morse taper shank without a tail tongue arranged in sequence. A plurality of first right-handed circular arc grooves are provided on the front guiding portion, and a plurality of second right-handed circular arc grooves are provided on the rear guiding portion.

[0018] Further, the lead of both the front guiding portion and the rear guiding portion is 300 mm.

[0019] Further, a double taper pre-guiding portion is provided at the end of the front guiding portion.

[0020] Further, the main cutting edge angle of the cutting and extruding portion is 1°.

[0021] Further, a wave spring washer is provided at the bottom of the positioning hole.

[0022] Further, the fixture is connected to the workpiece through a positioning pin.

[0023] In the above-mentioned rigid reamer machining bimetallic bushing machine tool, during machining, the workpiece is fixed on the positioning hole of the fixture and secured. The main shaft rotates and drives the rigid reamer to move rightward, entering the front guide. The movable center point moves leftward and abuts against the center hole of the workpiece. The slide is controlled to make the workpiece feed until the machining is completed. During the above machining process, since the rigid reamer is connected to the main shaft through the tool shank locking screw, the rigid reamer only makes a rotational movement on the power source. During the axial movement of the workpiece, there is a slight radial compensation float to maintain good following movement, relieve the moving inertia of the workpiece, and reduce the microscopic dimensional changes caused by the radial movement relative to the rigid reamer. At the same time, the rigid reamer has front and rear guiding parts to ensure self-aligning before machining and self-guiding during the cutting process, so as to ensure that the machining coaxiality accuracy is in a stable state. And the rigid reamer does not have the conventional tool's reverse taper structure, so that the rigid reamer's cutting edge band extrudes on the machined surface of the workpiece, increasing the density of the surface material of the part, ensuring that the machined surface is bright, increasing the contact area with the shaft, reducing the pressure on the contact surface, and extending the actual service life of the bimetallic bushing, achieving the machining effect of a reamer-type tool to reach the efficacy of an extrusion tool. In addition, the rigid reamer is installed at the spindle end of the power source. Because of the front and rear guiding parts, the rigid reamer is relatively long. To improve the overall rigidity, a rear support device (movable center point) is designed. It starts to act after the front guiding part of the rigid reamer enters the workpiece until it abuts against the center hole at the very front end of the rigid reamer, achieving the goal of improving the stiffness of the tool system and stabilizing the machining. Furthermore, the cutting edge of the rigid reamer is different from the main cutting edge angle of 3 - 15° designed for conventional hole machining tools. It has two small-angle main cutting edges (cutting and extrusion parts) in the forward and backward directions, and the main cutting edge angle is only 1°, effectively taking into account the functions of guiding and cutting. At the same time, three spiral arc grooves are designed on the front and rear guiding parts of the rigid reamer to store the tiny chips generated during the scraping with copper alloy during the guiding process, preventing the chips from getting stuck on the guiding cylinder and causing sintering between the guiding cylinder and the bushing, and preventing the machined hole wall from being scratched due to the presence of the chips. Finally, the entire equipment only requires a common platform with a guide rail to install the three major components of the power spindle, the slide, and the telescopic movable center point, meeting the process basic requirements of simplifying the equipment structure and efficient and stable machining. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a schematic structural diagram of the rigid reamer machining bimetallic bushing machine tool in the first embodiment of the present invention;

[0025] Figure 2 is Figure 1 an enlarged structural diagram of the rigid reamer in the rigid reamer machining bimetallic bushing machine tool in;

[0026] Figure 3 is Figure 2 a left view of the rigid reamer in.

[0027] Description of Main Component Symbols:

[0028] Base 10 Morse Taper Shank Without Tailstock 44 Transmission Part 80 Spindle 20 Double Taper Pre-Guide Part 45 Transmission Rod 81 Tool Holder Locking Screw 30 Fixture 50 Steering Transmission Gear 82 Rigid Reamer 40 Sliding Table 51 Drive Mechanism 90 Front Guide Part 41 Tailstock 60 Workpiece 100 First Right-Handed Circular Arc Groove 411 Cylinder 61 Left Bushing of Workpiece 101 Cutting and Extrusion Part 42 Tailstock Inlet Pipe 62 Right Bushing of Workpiece 102 Rear Guide Part 43 Tailstock Exhaust Pipe 63 Second Right-Handed Circular Arc Groove 431 Live Center 70

[0029] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0030] For ease of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0031] It should be noted that when an element is referred to as "fixedly provided on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] Please refer to Figures 1 to 3 , a machine tool for processing a bimetallic bushing with a rigid reamer provided by an embodiment of the present invention includes a base 10, a main shaft 20 provided on one side of the upper end of the base 10, a tool shank locking screw 30 provided in the main shaft 20, a rigid reamer 40 connected to the tool shank locking screw 30, a fixture 50 provided on the right side of the rigid reamer 40, a tailstock 60 provided on the right side of the fixture 50, and a cylinder 61 connected to the tailstock 60. A movable center 70 is provided at one end of the tailstock 60 close to the fixture 50. One end of the tool shank locking screw 30 away from the rigid reamer 40 is connected to a driving mechanism 90 through a transmission member 80. The lower end of the fixture 50 is slidably connected to the base 10. A positioning hole (not shown in the figure) is provided at a position of the fixture 50 corresponding to the workpiece.

[0034] In the above-mentioned rigid reamer machining bimetallic bushing machine tool, during machining, the workpiece 100 is fixed on the positioning hole of the fixture 50 and secured. The main shaft 20 rotates, which in turn drives the locking screw 30 of the locking tool bar to move leftward, causing the rigid reamer 40 to move rightward and enter the front guide. The movable center point 70 moves leftward and abuts against the center hole of the workpiece 100, controlling the movement of the fixture 50 to make the workpiece 100 feed until the machining is completed. During the above machining process, since the rigid reamer 40 is connected to the main shaft 20 through the tool bar locking screw 30, the rigid reamer 40 only makes a rotational movement in terms of the power source. During the axial movement of the workpiece 100, there is a slight radial compensation float to maintain good following movement, relieve the moving inertia of the workpiece, and reduce the microscopic dimensional changes caused by the radial movement relative to the rigid reamer 40, thereby improving the machining accuracy and dimensional stability.

[0035] In an embodiment of the present invention, the lower end of the fixture 50 is connected to the base 10 through a slide table 51. Specifically, in this embodiment, the slide table 51 slides on the base 10 through a slide rail to drive the movement of the workpiece 100.

[0036] In an embodiment of the present invention, an endstock inlet pipe 62 and an endstock exhaust pipe 62 communicating with the pipe body are provided on the pipe body of the air cylinder 61 to achieve the intake and exhaust of the air cylinder 61.

[0037] In an embodiment of the present invention, the driving mechanism 90 is a motor, and the transmission member 80 includes a transmission rod 81 and steering transmission gears 82 at both ends of the transmission rod 81.

[0038] In an embodiment of the present invention, the rigid reamer 40 includes a front guide portion 41, a cutting and extrusion portion 42, a rear guide portion 43, and a Morse taper shank without a tail tongue 44 arranged in sequence. Three first right-handed circular arc grooves 411 are provided on the front guide portion 41, and three second right-handed circular arc grooves 431 are provided on the rear guide portion 43. The first right-handed circular arc grooves 411 and the second right-handed circular arc grooves 431 are used to store the fine chips generated during the scraping with the copper alloy during the guiding process, prevent the chips from getting stuck on the guiding cylinder and causing sintering between the guiding cylinder and the bushing, and prevent the machined hole wall from being scratched due to the presence of the chips. Specifically, in the embodiment of the present invention, the lead of both the front guide portion 41 and the rear guide portion 43 is 300 mm. A double-taper pre-guide portion 45 is provided at the end of the front guide portion 41. The main cutting edge angle of the cutting and extrusion portion 42 is 1°. A wave spring washer (not shown in the figure) is provided at the bottom of the positioning hole. The fixture 50 is connected to the workpiece 100 through a positioning pin.

[0039] The machining method of the rigid reamer machining bimetallic bushing machine tool provided by the present invention is as follows:

[0040] 1) The rigid reamer 40 is locked with the arbor locking screw 30 to form a rigid connection with the spindle 20;

[0041] 2) The fixture 50 is fixed on the slide 51, and the rod of the workpiece 100 is placed in the positioning hole of the fixture 50. A wave spring washer (not marked in the figure) is placed on the fixture 50 to support the workpiece, so that the workpiece can have 1mm of space to move downward on the fixture 50; a positioning pin (not shown in the figure) with a 0.5mm gap with the positioning hole (not marked in the figure) of the workpiece 100 is inserted for guiding positioning;

[0042] 3) Start the equipment, the driving mechanism (motor) 90 drives the spindle 20 to start rotating at a low speed, and the slide 12 moves a distance toward the tool 15, so that the right end 6 of the part enters the front guide portion 4 of the rigid reamer, and stops moving until the center hole of the front guide portion 41 of the rigid reamer 40 is exposed;

[0043] 4) The cylinder 61 on the tailstock 60 takes in air through the tailstock air inlet pipe 62, and exhausts air through the tailstock exhaust pipe 62. The cylinder 61 pushes the movable top 70 to start moving toward the rigid reamer 40 until the movable top 70 stops moving after it pushes against the center hole of the front guide portion 41 of the rigid reamer 40, and keeps pushing in reliably;

[0044] 5) The slide 51 on which the fixture 50 and the workpiece 100 are installed moves in a fast forward manner, and stops moving in a fast forward manner after the bushing 101 on the left side of the workpiece 100 approaches the cutting and pressing portion 42 of the rigid reamer 40;

[0045] 6) The slide 51 starts to move, the driving mechanism 90 drives the spindle 20 to rotate at the processing speed, and the cutting and extruding portion 42 of the rigid reamer 40 on the spindle 20 starts to cut the copper layer of the bimetallic bushing until the two bimetallic bushings of the workpiece 100 are processed; at this time, the right bushing 102 of the workpiece 100 is located on the left side of the cutting and extruding portion 42 of the rigid reamer 40, and the processed left bushing 101 and right bushing 102 of the workpiece completely enter the rear guide portion 43 of the rigid reamer 40;

[0046] 7) The slide 51 starts to move rapidly toward the tailstock 60 , and when the end surface of the bushing 102 on the right side of the workpiece 100 approaches the position of the movable top 70 , the slide 51 stops moving;

[0047] 8) The tailstock air inlet pipe 62 of the cylinder 61 takes in air, and the tailstock air exhaust pipe 63 exhausts air, and the cylinder 61 pushes the movable top 70 to move to the right, so that the movable top 70 exits the positioning work, returns to the rightmost side, and stops;

[0048] 9) The slide 51 where the workpiece 100 is located continues to move rightward until it returns to the starting point, the drive mechanism 90 is powered off, and the spindle 20 stops rotating; the processing of the bimetallic bushing is completed.

[0049] In the above processing process, since the rigid reamer 40 is connected to the main shaft 20 through the tool rod locking screw 30, the rigid reamer 40 only rotates on the power source. During the axial movement of the workpiece 100, there is a slight radial compensation float to maintain good following movement, relieve the moving inertia of the workpiece, reduce the microscopic dimensional changes caused by the radial movement relative to the rigid reamer 40, and improve the machining accuracy and machining stability. At the same time, the rigid reamer 40 has front and rear guiding parts to ensure self-aligning before machining and self-guiding during the cutting process, so as to ensure that the accuracy of machining coaxiality is in a stable state. Moreover, the rigid reamer 40 does not have the reverse taper structure of conventional tools, so that the cutting edge band of the rigid reamer 40 extrudes on the machined surface of the workpiece, increases the density of the surface material of the part, ensures that the machined surface is bright, increases the contact area with the shaft, reduces the pressure on the contact surface, extends the actual service life of the bimetallic bushing, and obtains the processing effect of a reamer-type tool to achieve the effect of an extrusion tool. In addition, the rigid reamer 40 is installed at the spindle end of the power source. Because of the front and rear guiding parts, the rigid reamer 40 is relatively long. For the need to improve the overall rigidity, a rear support device (movable center 70) is designed. It starts to act after the front guiding part 41 of the rigid reamer 70 enters the workpiece 100 until it reaches the center hole at the front end of the rigid reamer 40, achieving the goal of improving the stiffness of the tool system and stabilizing the machining. Furthermore, the cutting edge of the rigid reamer 40 is different from the main cutting edge angle of 3-15° designed for conventional hole machining tools. It has two small-angle main cutting edges (cutting and extrusion parts) in the forward and backward directions, and the main cutting edge angle is only 1°, effectively taking into account the functions of guiding and cutting. At the same time, three spiral arc grooves (the first right-handed arc groove 411 and the second right-handed arc groove 431) are designed on the front and rear guiding parts of the rigid reamer 40 to store the tiny chips generated during the scraping with copper alloy during the guiding process, prevent the chips from getting stuck on the guiding cylinder and causing sintering between the guiding cylinder and the bushing, and prevent the machined hole wall from being scratched due to the presence of the chips. Finally, the whole equipment only needs a common platform with a guide rail to install the three major components of the power spindle 20, the slide table 51 and the telescopic movable center 70, meeting the process basic requirements of simplifying the equipment structure and efficient and stable machining.

[0050] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A machine tool for processing bimetallic bushings with a rigid reamer, characterized in that, It includes a base, a main shaft provided on one side of the upper end of the base, a tool rod locking screw provided in the main shaft, a rigid reamer connected to the tool rod locking screw, a fixture provided on the right side of the rigid reamer, a tailstock provided on the right side of the fixture, and a cylinder connected to the tailstock. An active center is provided at one end of the tailstock close to the fixture. One end of the tool rod locking screw away from the rigid reamer is connected to a driving mechanism through a transmission member. The lower end of the fixture is slidably connected to the base, and a positioning hole is provided at a position corresponding to the workpiece on the fixture.

2. A machine tool for processing bimetallic bushings with a rigid reamer according to claim 1, characterized in that, The lower end of the fixture is connected to the base through a slide table.

3. A machine tool for machining a bimetallic bushing with a rigid reamer according to claim 1, characterized in that, An air inlet pipe for the tailstock and an exhaust pipe for the tailstock communicating with the pipe body are provided on the pipe body of the cylinder.

4. A machine tool for machining a bimetallic bushing with a rigid reamer according to claim 1, characterized in that, The driving mechanism is a motor, and the transmission member includes a transmission rod and steering transmission gears at both ends of the transmission rod.

5. A machine tool for machining a bimetallic bushing with a rigid reamer according to claim 1, characterized in that, The rigid reamer includes a front guiding portion, a cutting and extruding portion, a rear guiding portion, and a Morse taper shank without a tail tongue arranged in sequence. A plurality of first right-handed circular arc grooves are provided on the front guiding portion, and a plurality of second right-handed circular arc grooves are provided on the rear guiding portion.

6. A machine tool for processing bimetallic bushings with a rigid reamer according to claim 5, characterized in that, The lead of both the front guiding portion and the rear guiding portion is 300 mm.

7. A machine tool for machining a bimetallic bushing with a rigid reamer according to claim 5, characterized in that, A double-taper pre-guiding portion is provided at the end of the front guiding portion.

8. A machine tool for processing a bimetallic bushing with a rigid reamer according to claim 5, characterized in that, The main cutting edge angle of the cutting and extruding portion is 1°.

9. A machine tool for machining a bimetallic bushing with a rigid reamer according to claim 1, characterized in that, A wave spring washer is provided at the bottom of the positioning hole.

10. A machine tool for machining a bimetallic bushing with a rigid reamer according to claim 1, characterized in that, The fixture is connected to the workpiece through a positioning pin.

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