A vertical multi-axis multi-station needle valve body hole seat surface large end face grinder

Abstract

The present application belongs to the technical field of grinding machine, in particular to a vertical multi-axis multi-station needle valve body middle hole seat surface large end surface grinding machine, the electric spindle is vertically arranged, eliminating the deflection of the rotor shaft and the grinding wheel rod caused by gravity in the usual horizontal arrangement state; the grinding radial feeding direction of the grinding wheel is the radial direction of the radius of the rotary table, rather than the tangent direction of the circumference, thus greatly reducing the influence of the workpiece hole diameter grinding size caused by the indexing error of the rotary table, and the workpiece hole diameter size consistency is good; before rough grinding the middle hole, there is a station for grinding the chamfer at both ends of the middle hole, to achieve the consistency of the starting and ending positions of the middle hole grinding, providing a guarantee for the grinding taper of the middle hole; after end surface grinding, there is a station for brushing the middle hole with a brush, further brushing off the grinding micro burrs at both ends of the middle hole, providing a guarantee for the sliding type of the needle valve pair.

Description

Technical Field

[0001] This invention belongs to the field of grinding machine technology, specifically a vertical multi-axis multi-station needle valve body central hole seat surface large end face grinding machine. Background Technology

[0002] This invention relates to a specialized grinding machine for the fuel pump and nozzle industry. Fuel pumps and nozzles are the heart of diesel engines, with the needle valve assembly being one of the most critical components. It affects the performance, emissions, and service life of the diesel engine. The needle valve body operates under high pressure and high temperature conditions, requiring exceptionally high precision in its central bore, seat surface, and large end face. The central bore diameter of the needle valve body is typically φ4-φ6, a blind bore, with a seat surface depth to bore diameter ratio greater than 4:1. For common rail injectors, this ratio reaches as high as 10:1, making machining quite difficult. The GB / T5772-2010 standard requires that the lift tolerance of the needle valve assembly be ±0.03mm for lift <0.4mm, and the perpendicularity requirement of the large end face of the needle valve body to the central bore be 0.03mm. The lift dimension is determined by the accuracy of the distance from the seat surface to the large end face of the needle valve body (commonly known as the seat surface depth). Therefore, to ensure the accuracy of the seat surface depth and the perpendicularity of the large end face to the central bore, it is best to clamp the large end face, central bore, and seat surface in one operation.

[0003] Currently, some companies use expensive imported machine tools for processing, resulting in high costs.

[0004] Existing domestically produced machine tools mainly include horizontal three-axis single-station, horizontal two-axis single-station, and horizontal five-axis six-station rotary machine tools. Single-station machine tools have relatively low processing efficiency. Although horizontal five-axis six-station rotary machine tools have higher efficiency, the direction of the workpiece grinding side generatrix is ​​consistent with the direction of the rotary indexing and positioning error. Therefore, the rotary indexing and positioning error is superimposed on the workpiece hole diameter grinding error, resulting in a large workpiece hole diameter variation, actually exceeding 0.02mm. This is not conducive to the selection and matching of parts, and its application is greatly limited, preventing its widespread use in production.

[0005] Both imported machine tools and existing domestic machine tools share a common drawback: all the machine tools are horizontal type. Since the workpiece has a blind hole with a small aperture, to meet the cooling requirements for grinding, a through-coolant type motorized spindle, grinding wheel rod and grinding wheel are required. The manufacturing of the hollow motorized spindle, hollow grinding wheel rod and grinding wheel with spray holes is complex; the coaxiality error between the inner hole and outer circle of the rotor shaft of the hollow motorized spindle makes it difficult to achieve balance under ultra-high-speed rotation of 100,000 rpm; the manufacturing precision requirement is high; the sealing of the water outlet structure is complex; the coaxiality error between the inner hole and outer circle of the high-speed rotating hollow alloy grinding wheel rod has high precision requirements, dynamic balance is not easy to achieve, and the rigidity of the grinding wheel rod is reduced; the discontinuous surface of the hollow CBN superhard grinding wheel caused by radial spray holes leads to straightness error defects on the workpiece surface during the grinding process, and the force exerted by the intermittently distributed spray holes on the circumferential surface of the grinding wheel on the workpiece surface, which is opposite to the radial feed force of grinding, also produces adverse effects. All the above disadvantages will lead to errors in grinding roundness and straightness, increasing the risk factors of unqualified workpieces in the production process, thus increasing the difficulty of machine tool manufacturing and raising the configuration requirements of the machine tool. Some machine tools of this type use a motorized spindle with an air bearing structure, which is even more unfavorable.

[0006] In addition, horizontal three-axis and two-axis machine tools can only complete the grinding of the central hole and the seat surface, and the grinding of the large end face requires secondary clamping on another machine tool for processing, which not only affects efficiency, but also increases the difficulty of controlling the accuracy of the lift dimension and the perpendicularity accuracy of the large end face relative to the central hole. Therefore, a vertical multi-axis multi-station grinding machine for the central hole, seat surface and large end face of the needle valve body is proposed to solve the above problems. Contents of the Invention

[0007] To make up for the deficiencies of the prior art and solve at least one technical problem raised in the background art, the present invention proposes a vertical multi-axis multi-station grinding machine for the central hole, seat surface and large end face of the needle valve body.

[0008] The technical solution adopted by the present invention to solve its technical problems is as follows: The vertical multi-axis multi-station grinding machine for the central hole, seat surface and large end face of the needle valve body according to the present invention includes a machine bed. The overall shape of the machine bed is a "earth"-shaped circle with a hollow circular axis. The upper half column part of the machine bed is an octagonal prism, and the edge planes are perpendicular to the bottom surface of the machine bed. A bent plate is fixed on the edge plane of the machine bed, and a processing unit I, a processing unit II, a processing unit III, a processing unit IV, a processing unit V, a processing unit VI and a processing unit VII are installed on the bent plate; a numerical control annular indexing table system is installed on the round table at the waist of the machine bed, and a numerical control annular indexing table system is installed at the end of the machine bed; eight workpiece clamping and rotating units are evenly distributed on the circumference of the numerical control annular indexing table system; the lower half of the machine bed corresponds to the upper half and is in the shape of an octagonal prism, and seven workpiece rotation driving units are installed on the edge planes; the machine bed is equipped with a high-pressure grinding fluid system.

[0009] Preferably, machining units I, II, III, IV, V, VI, and VII are equipped with vertical slides on their sidewalls. The vertical slides on machining units I, II, III, and VII are also equipped with transverse slides on their sidewalls. An electric spindle is mounted at the end of each transverse slide. The forward and backward movement of the transverse slide is perpendicular to the plane of the upper half of its corresponding machine bed and is radial to the annular rotary indexing system. Machining units IV and V are equipped with oblique slides on their sidewalls. The electric spindle is vertically mounted on the oblique slide, and the plane of the oblique slide's forward and backward movement is perpendicular to the plane of the upper half of its corresponding machine bed. The grinding end face electric spindle on the vertical slide of machining unit VI is vertically mounted and only performs vertical forward and backward movement.

[0010] Preferably, a brush is mounted on the spindle of the electric spindle on the VII machining unit.

[0011] Preferably, the upper part of the support of the workpiece rotation drive unit is a bearing seat, a hollow piston rod type cylinder, a spline shaft, and a dial. The top end of the spline shaft is fixed with the dial. The spline shaft is installed inside the hollow piston rod. The spline shaft rises and falls with the hollow piston rod. When the hollow piston rod rises, the dial and the workpiece clamping rotation unit close the transmission, and the electric spindle of the corresponding processing unit moves to perform workpiece processing. When the hollow piston rod falls, the transmission is disengaged. The CNC ring rotary indexing table system can rotate around the axis of the bed to realize the conversion of different processing positions of the workpiece.

[0012] Preferably, the pressure of the high-pressure grinding fluid is not less than 0.6 MPa, and the high-pressure grinding fluid is sprayed into one side of the inner wall of the workpiece hole and returned from the opposite side.

[0013] The beneficial effects of this invention are:

[0014] The present invention achieves its objective through the following technical solutions.

[0015] The machine tool consists of a bed, 7 machining units (including CNC slides, electric spindles, grinding wheels, etc.), a power unit with an open loading and unloading chuck, a high-pressure grinding fluid system, an electrical control CNC system, an air supply pipeline and an automatic lubrication system, 8 workpiece clamping and rotating units, 7 workpiece rotation drive units, a high-precision CNC ring indexing table system, a protective cover, and an oil mist separation unit.

[0016] The overall shape of the cast iron bed of the machine tool is a "tu"-shaped circle, the axis of the bed is hollow, the upper column part of the bed is an octagonal prism, the edge planes are perpendicular to the bottom surface of the bed, and 7 machining units and 1 power unit for opening the loading / unloading chuck are mounted via angle plates. The CNC annular indexing table system is installed on the circular platform at the waist of the "tu"-shaped bed, and 8 workpiece clamping and rotating units are evenly distributed on the CNC annular indexing table along the circumference. The lower half of the machine tool bed is correspondingly an octagonal prism matching the upper half, and 7 workpiece rotation driving units are installed on the edge planes.

[0017] The 7 machining units (corresponding to 7 stations) are respectively ① chamfering both ends of the central hole ② rough grinding the central hole ③ finish grinding the central hole ④ rough grinding the seating surface ⑤ finish grinding the seating surface ⑥ grinding the large end face ⑦ brushing the central hole with a brush. The grinding motorized spindles of the 7 machining units, 1 power unit for opening the loading / unloading chuck, and 8 workpiece clamping and rotating units are all vertically arranged on the machine tool. 8 angle plates are fixed on the 8 planes of the upper half of the bed, the lifting, advancing and retracting of the grinding or central hole brushing motorized spindles of the 7 machining units are realized by the vertical sliding tables and servo motors installed on the angle plates; the perpendicularity between the vertical sliding tables and the annular rotary indexing table is realized by adjusting the jackscrews under the angle plates; the lateral advancing and retracting of the motorized spindles at stations ①, ②, ③ and ⑦ are realized by the lateral sliding tables and servo motors installed on the vertical sliding tables, the advancing and retracting direction of the lateral sliding tables is perpendicular to the corresponding prism plane of the upper half of the bed, which is the radial direction of the annular rotary indexing table; the oblique advancing and retracting of the motorized spindles at stations ④ and ⑤ are realized by the oblique sliding tables and servo motors fixed on the vertical sliding tables, the movement plane of the oblique sliding tables for advancing and retracting is perpendicular to the corresponding prism plane of the upper half of the bed; the motorized spindle at station ⑥ only performs vertical advancing and retracting.

[0018] The workpiece clamping and rotating unit adopts high-precision rolling bearings to realize high-precision rotation of the workpiece, providing the necessary conditions for ensuring the roundness of the workpiece. A diaphragm chuck is used for clamping, the opening of the diaphragm chuck is realized by the push of the cylinder of the power unit for opening the loading / unloading chuck, and the clamping of the chuck is realized by its own elasticity. The annular wheel dresser is integrally mounted on the upper end of the workpiece clamping and rotating unit, and rotates at the same speed as the unit.

[0019] For the 7 workpiece rotation driving units in the lower half of the bed, ordinary motors are used for driving, and the rotational speed required for each station is obtained through belt transmission. The rotation driving units are provided with cylinder-driven opening and closing mechanisms, which realize the opening and closing of transmission through the extension and retraction of the cylinder rod. After closing, the motorized spindle of the machining unit moves to perform workpiece machining; after disengagement, the CNC annular rotary indexing table can rotate to realize the conversion of different machining stations for the workpiece.

[0020] The flat-arc hole nozzles of the high-pressure grinding fluid system are arranged corresponding to the 7 machining units, injecting into the workpiece hole. The high-pressure grinding fluid is sprayed into one side of the inner wall of the workpiece hole and returns from the opposite side, realizing the circulation of the high-pressure grinding fluid in the workpiece hole.

[0021] The air supply pipeline and automatic lubrication system complete the oil mist lubrication of the electric spindle and the movement of the cylinder.

[0022] The oil mist separator on top of the machine tool draws in the oil mist generated during processing and forms oil droplets that flow back to the oil sump at the bottom of the machine tool.

[0023] The machine tool adopts a fully enclosed protective cover to prevent high-pressure grinding fluid from splashing and oil mist from escaping. The overall shape is circular, and the protective cover is divided into upper and lower halves, each of which is further divided into 4 panels. It can slide along the arc track groove, allowing for a large range of opening and closing, which is convenient for operation.

[0024] All machine tool movements are automated by the CNC system.

[0025] The advantages and positive effects of this invention are as follows:

[0026] 1. Vertical grinding eliminates the need for a centrally located water-cooled electric spindle, grinding wheel rod, and grinding wheel, achieving excellent cooling. This solves the complex manufacturing issues of hollow electric spindles, hollow grinding wheel rods, and grinding wheels with nozzles required for centrally located water-cooled grinding. It also addresses the challenges of balancing at ultra-high speeds of 100,000 rpm due to coaxiality errors between the hole and outer diameter of the hollow electric spindle rotor shaft, the sealing issues of the water-cooled structure, the imbalance caused by coaxiality errors between the hole and outer diameter of the high-speed rotating hollow alloy grinding wheel rod, the reduced rigidity of the grinding wheel rod, the discontinuity of the grinding wheel surface caused by the radial nozzles of the hollow CBN superhard grinding wheel leading to workpiece surface straightness errors during grinding, the adverse effects caused by the force of the intermittently distributed nozzles on the workpiece surface acting opposite to the radial feed force, and the grinding roundness and straightness errors caused by the aforementioned disadvantages of the centrally located water-cooled grinding structure.

[0027] 2. The grinding radial feed direction of the grinding wheel is the radial direction of the rotary table, rather than the tangential direction of the circumference. This greatly reduces the impact of the rotary table's indexing and positioning error on the workpiece hole diameter grinding size (using an indexing plate with an indexing accuracy of ±18sec, the impact on the hole diameter error is reduced to 0.002), resulting in good consistency of the workpiece hole diameter size.

[0028] 3. This machine tool is a multi-station machine tool. It can complete the grinding of the workpiece's central hole, seat surface, and large end face in one clamping. It is easy to control the depth of the seat surface and the perpendicularity accuracy of the large end face relative to the central hole.

[0029] 4. This machine tool can process multiple workpiece axes simultaneously, resulting in high production efficiency;

[0030] 5. The workpiece hole is kept full of grinding fluid, the grinding wheel is immersed in the grinding fluid, there is no air in the grinding zone, there are no sparks in the grinding process, and there is no oxide film on the grinding surface. This overcomes the problem of reduced wear resistance and corrosion resistance of the workpiece surface caused by oxide film. The grinding fluid in the workpiece hole is circulated.

[0031] 6. The electric spindle is arranged vertically, which eliminates the wobble of the rotor shaft and grinding wheel rod caused by gravity in the usual horizontal arrangement.

[0032] 7. Before rough grinding the center hole, grind the chamfers at both ends of the center hole first. This will result in a higher consistency between the starting and ending positions during the grinding of the center hole, and a better grinding taper of the center hole.

[0033] 8. The last station has a brush to clean the central hole, further removing the microburrs at both ends of the central hole, thus ensuring the sliding of the needle valve assembly. Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0035] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0036] Figure 2 for Figure 1 Top view;

[0037] Figure 3 for Figure 2 View A of component 1, view B of component 2, and view C of component 3;

[0038] Figure 4 for Figure 2 View of component 4 in direction D, and view of component 5 in direction E;

[0039] Figure 5 for Figure 2 F-direction view of component 6;

[0040] Figure 6 for Figure 2 G-direction view of component 7;

[0041] Figure 7 for Figure 2 Main view of component 8;

[0042] Figure 8 for Figure 1 Enlarged view of component 13.

[0043] Legend:

[0044] 1. Machining Unit I; 2. Machining Unit II; 3. Machining Unit III; 4. Machining Unit IV; 5. Machining Unit V; 6. Machining Unit VI; 7. Machining Unit VII; 8. Loading and unloading power unit; 9. High-pressure grinding fluid system; 10. Electrical control system; 11. Air supply pipeline and automatic lubrication system; 12. Workpiece clamping and rotation unit; 13. Workpiece rotation drive unit; 14. CNC circular indexing table system; 15. Bed; 16. Protective cover section; 17. Oil mist separation section; 18. Vertical slide verticality adjustment plate; 19. Bending plate; 20. Vertical slide; 21. Vertical slide servo motor ; 22. Transverse slide table; 23. Transverse slide table servo motor; 24. Electric spindle mounting base; 25. Electric spindle; 26. Grinding wheel; 27. Grinding wheel rod; 28. Angled slide table servo motor; 29. ​​Angled slide table; 30. Adjustable mounting base; 31. 60° pointed grinding wheel; 32. End face grinding electric spindle mounting base; 33. End face grinding electric spindle; 34. End face grinding wheel; 35. Brush; 36. Cylinder; 37. Bracket; 38. Motor; 39. Belt; 40. Splined sleeve drive shaft; 41. Bearing housing; 42. Hollow piston rod cylinder; 43. Hollow piston rod; 44. Splined shaft; 45. Dial. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] The present invention will be further described below with reference to the accompanying drawings.

[0047] like Figure 1 , Figure 2 As shown, this machine tool includes a bed 14, 7 machining units 1-7 (including CNC slides, electric spindles, grinding wheels, etc.), a power unit 8 for opening and closing the loading and unloading chucks, a high-pressure grinding fluid system 9, an electrical control CNC system 10, an air supply pipeline and automatic lubrication system 11, 8 workpiece clamping and rotating units 12, 7 workpiece rotation drive units 13, a CNC circular indexing table system 14, a protective cover section 16, and an oil mist separation section 17.

[0048] Combination Figure 7 , Figure 8 , Figure 3As shown, the piston rod of cylinder 36 on power unit 8, which opens the loading and unloading chuck, extends downward. The diaphragm chuck on workpiece clamping rotary unit 12 is opened by force, allowing the workpiece to be loaded. The piston rod of cylinder 36 retracts, and the diaphragm chuck contracts and clamps the workpiece due to its own elasticity. After the CNC ring indexing table system 14 rotates 45°, it automatically contracts and tightens. The workpiece rotates to the bottom of processing unit 1, and the hollow piston rod 43 of the corresponding rotary drive unit 13 rises, closing the transmission. The motor 38 of rotary drive unit 13 starts, driving the workpiece clamping rotary unit 12 to rotate. The high-pressure grinding fluid system 9 starts supplying high-pressure grinding fluid, the electric spindle on processing unit 1 starts, the vertical slide 20 moves down, the grinding wheel 26 enters the workpiece hole, and the horizontal slide 22 performs horizontal feed, starting the ① station grinding.

[0049] After grinding is completed, the horizontal slide 22 retracts, the vertical slide 20 retracts, the hollow piston rod 43 descends, the transmission disengages, the CNC ring indexing table system 14 rotates 45° again and locks, the workpiece is moved to the bottom of the processing unit 2, and the corresponding components perform the same actions as described above to perform ② station grinding. Similarly, ③ station grinding is then performed.

[0050] Combination Figure 4 As shown, after the workpiece enters station ④, the hollow piston rod 43 of the rotary drive unit 13 rises, closing the transmission. The motor 38 of the rotary drive unit 13 starts, driving the workpiece clamping rotary unit 12 to rotate. The high-pressure grinding fluid system 9 starts supplying high-pressure grinding fluid, and the electric spindle on the machining unit 4 starts. Correspondingly, the vertical slide 20 moves down, and the inclined slide 29 moves diagonally downward. The vertical slide 20 performs axial feed for grinding the workpiece seat surface, and the inclined slide performs oscillating motion in the parallel direction of the seat surface generatrix. After completion, the vertical slide 20 retracts, the inclined slide 29 retracts, the hollow piston rod 43 descends, the transmission disengages, and the CNC ring indexing table system rotates 45° again. The workpiece enters station ⑤, and the corresponding components perform the same actions as in station ④.

[0051] Combination Figure 5 As shown, after the workpiece enters station ⑥, the hollow piston rod 43 of the rotary drive unit 13 rises, the transmission closes, the motor 38 of the rotary drive unit 13 starts, driving the workpiece clamping rotary unit 12 to rotate, the high-pressure grinding fluid system 9 starts supplying high-pressure grinding fluid, the electric spindle on the machining unit 6 starts, and the vertical slide 20 moves down to perform large end face grinding on the workpiece. After the large end face grinding is completed, the vertical slide 20 retracts, the inclined slide 29 retracts, the hollow piston rod 43 descends, the transmission disengages, the CNC ring indexing table system rotates 45° again, and the workpiece enters station ⑦.

[0052] Combination Figure 6As shown, the corresponding actions of each component are the same as in station ①, completing the brushing of the center hole. After the workpiece returns to the loading and unloading station, the piston rod of the cylinder 36 on the power unit 8 that opens the loading and unloading chuck extends downward, and the diaphragm chuck on the workpiece clamping rotary unit 12 is forced open to remove the workpiece.

[0053] The eight workpiece clamping rotary units 12 can each independently perform loading and unloading actions when in the loading / unloading station. The above describes and illustrates the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A vertical multi-axis multi-station needle valve body bore seat surface large end face grinding machine, comprising a bed (15), characterized in that, The bed (15) is circular in shape, with a hollow center. The upper column of the bed (15) is an octagonal prism with its edge plane perpendicular to the bottom surface of the bed (15). A curved plate (19) is fixed on the edge plane of the bed (15). The curved plate (19) is equipped with machining units I (1), II (2), III (3), IV (4), V (5), VI (6), and VII (7). A CNC circular indexing table system (14) is installed on the circular platform at the waist of the bed (15). The CNC circular indexing table system (14) has eight workpiece clamping points evenly distributed around its circumference. Rotating unit (12); the lower half of the bed (15) is an octagonal prism corresponding to the upper half, and seven workpiece rotation drive units (13) are installed on the edge plane; the bed (15) is equipped with a high-pressure grinding fluid system (9); vertical slides (20) are installed on the side walls of machining units I (1), II (2), III (3), IV (4), V (5), VI (6) and VII (7), and transverse slides (22) are installed on the side walls of the vertical slides (20) on machining units I (1), II (2), III (3) and VII (7), and the ends of the transverse slides (22) are... An electric spindle (25) is installed. The forward and backward movement of the transverse slide (22) is perpendicular to the plane of the upper half of its corresponding bed (15) and is radial to the CNC ring indexing table system (14). An inclined slide (29) is installed on the side wall of machining unit IV (4) and machining unit V (5). The electric spindle (25) is vertically installed on the inclined slide (29). The plane of the forward and backward movement of the inclined slide (29) is perpendicular to the plane of the upper half of its corresponding bed (15). The grinding end face electric spindle (33) on the vertical slide (20) of machining unit VI (6) is vertically installed and only performs vertical forward and backward movement. The upper part of the bracket (37) of the workpiece rotation drive unit (13) The system consists of a bearing housing (41), a hollow piston rod cylinder (42), a spline shaft (44), and a dial (45). The top of the spline shaft (44) is fixed with the dial (45). The spline shaft (44) is installed inside the hollow piston rod (43). The spline shaft (44) moves up and down with the hollow piston rod (43). When the hollow piston rod (43) rises, the dial (45) and the workpiece clamping rotary unit (12) close the transmission, and the electric spindle (25) of the corresponding processing unit moves, so that the workpiece can be processed. When the hollow piston rod (43) falls, the transmission is disengaged, and the CNC ring indexing table system (14) can rotate around the axis of the bed (15) to realize the conversion of different processing positions of the workpiece.

2. The vertical multi-axis multi-station needle valve body bore seat surface grinding machine according to claim 1, characterized in that: A brush (35) is mounted on the shaft of the electric spindle (25) on the VII machining unit (7).

3. A vertical multi-axis, multi-station needle valve body bore seat surface grinding machine according to claim 1, characterized in that: The pressure of the high-pressure grinding fluid is not less than 0.6 MPa. The high-pressure grinding fluid is sprayed into one side of the inner wall of the workpiece hole and returns from the opposite side.

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