Special device for finish turning of exhaust valve seat

Abstract

The invention discloses a special device for finish turning of an exhaust valve seat, which enables the exhaust valve seat processed by a working step A to be reliably positioned and a numerical control vertical lathe to carry out accurate and reliable turning, so that the quality of a product is ensured. The invention relates to an exhaust valve seat, which comprises a base, the base comprises a bottom plate and an upward convex positioning ring, the center of the bottom plate is provided with the upward convex positioning ring, the upward convex positioning ring is provided with a positioning spigot ring, and the spigot ring is arranged on the outer spigot ring surface of the valve face end of the exhaust valve seat in a profiling mode. A plurality of annularly distributed radial positioning screw holes are respectively formed in the upper surface of the bottom plate relative to the periphery of the upper convex positioning ring; each peripheral pressing accessory comprises a supporting rod, a movable pressing plate, a first screw rod and a locking nut; the concave pressing plate comprises a central circular plate, a plurality of transition conical surfaces and a plurality of upper pressing blocks, and the plurality of transition conical surfaces expanding outwards from bottom to top are arranged on the radial periphery of the central circular plate; and a second screw.

Description

Technical Field

[0001] The invention relates to the field of exhaust valve seat processing, in particular to a special device for fine turning of exhaust valve seats. Background Art

[0002] Exhaust valve seat (see Figure 1 ) As an important part of the exhaust valve, it works with the valve stem and other components to realize the opening and closing of the exhaust valve in the diesel engine combustion chamber, thereby controlling the exhaust gas discharge in the combustion chamber, ensuring the normal ventilation process of the diesel engine, and enabling the combustion process to proceed continuously and effectively. The existing processing method is to use CNC vertical lathe processing, clamp the appearance with four claws, and complete the fine processing of both ends in the height direction by dial calibration. However, the clamping accuracy of CNC vertical lathe equipment is not high, which leads to Figure 1 After the valve face end of the middle and lower end faces is processed through step A, the upper end face processing corresponding to the countersunk end corresponding to step B cannot guarantee the product processing quality; for this reason, it is urgent to develop a special positioning device that can reliably position the exhaust valve seat and perform step B processing. Summary of the invention

[0003] In view of the above problems, the present invention provides a special device for fine turning of exhaust valve seats, which enables the exhaust valve seats processed by step A to be reliably positioned, and the CNC vertical lathe performs precise and reliable turning processing, thereby ensuring the quality of the product.

[0004] A special device for finishing the exhaust valve seat, characterized in that it comprises:

[0005] The base comprises a bottom plate and an upper convex positioning ring, wherein a raised upper convex positioning ring is provided at the center of the bottom plate, and the upper convex positioning ring is provided with a positioning stop ring, and the stop ring is provided in the shape of an outer stop ring surface of the valve face end of the exhaust valve seat, and a plurality of radial positioning screw holes are respectively provided on the upper surface of the bottom plate relative to the outer periphery of the upper convex positioning ring;

[0006] A plurality of sets of peripheral pressing accessories, each set of peripheral pressing accessories includes a support rod, a movable pressing plate, a first screw rod, and a locking nut;

[0007] A concave pressure plate, comprising a central circular plate, a plurality of transition conical surfaces, and a plurality of upper pressure blocks, wherein the radial outer periphery of the central circular plate is provided with a plurality of transition conical surfaces expanding outward from bottom to top, and a corresponding upper pressure block is provided on the top of each transition conical surface, and the upper pressure block is arranged to protrude radially outward, and a stop notch is provided on the lower surface of the radial outer end of the upper pressure block, and the stop notch is provided on the radial inner upper surface of the inner countersunk hole located on the countersunk hole end surface of the exhaust valve seat;

[0008] and a second screw;

[0009] The bottom of the exhaust valve seat is positioned in a positioning stop ring arrangement;

[0010] It includes two positioning states. In the first positioning state, a plurality of groups of movable pressure plates of the peripheral pressure attachments press the convex outer ring surface of the exhaust valve seat; in the second positioning state, the concave pressure plate is pressed by the second screw rod so that the upper pressure block is positioned and pressed on the radial inner upper surface of the inner countersunk hole of the exhaust valve seat through the stop notch.

[0011] It is further characterized by:

[0012] The top of the support rod is provided with an upper convex positioning, the position of the movable pressing plate corresponding to the upper convex positioning is provided with a first positioning hole, and the movable pressing plate is provided with a long slot hole corresponding to the first screw rod, and the long slot hole enables the movable pressing plate to adjust the operation according to the actual position;

[0013] When the peripheral pressure attachment is in an assembled state, the top convex position of the support rod is inserted into the first positioning hole, the top of the first screw rod passes through the long slot hole and is threadedly connected with a locking nut, the bottom of the support rod is arranged closely against the upper surface of the bottom plate, the lower end of the first screw rod is threadedly connected to the radial positioning screw hole, and the movable pressure plate presses the convex outer ring surface of the exhaust valve seat;

[0014] In the first positioning state, the support rod is located at the radially outer side of the bottom plate relative to the first screw rod, which ensures that when the locking nut is tightened, the inner end of the movable pressing plate can reliably press against the convex outer annular surface of the exhaust valve seat;

[0015] The peripheral pressure attachment also includes a flat washer, and a flat washer is arranged between the locking nut and the movable pressure plate;

[0016] The second screw rod is equipped with an upper nut, the center circular plate is provided with a center through hole, and the center of the upper surface of the bottom plate is provided with a center positioning screw hole. The second screw rod passes through the center through hole and is threadedly connected to the center positioning screw hole. The upper nut is sleeved on the upper end of the second screw rod and is pressed and connected to the upper surface of the center circular plate.

[0017] After adopting the structure of the present invention, the wall thickness of the countersunk end of the exhaust valve seat is relatively thin, and there is deformation after the pressure plate is released. It is necessary to adopt a processing method of first semi-finishing turning with an outer pressure plate, then changing to an inner pressure plate to fine-turn the end plane and appearance, and finally using an inner hole sharp knife to fine-turn the countersunk hole and the root cleaning groove. Therefore, the processing method is divided into two steps, and the bottom of the exhaust valve seat is positioned at the positioning stop ring arrangement; the positioning of the exhaust valve seat is also divided into two steps. The first step, that is, the first positioning state, a plurality of groups of movable pressure plates of the peripheral pressure accessories press the convex outer ring surface of the exhaust valve seat, and then the inner countersunk hole at the countersunk end is turned by a turning tool. In the second step, the inner countersunk hole is reliably positioned by the concave pressure plate, the peripheral pressure accessories are removed, and the end plane and the appearance of the countersunk hole end are turned by a turning tool, and finally the countersunk hole and the root cleaning groove are finely turned with an inner hole sharp knife; it enables the exhaust valve seat processed by step A to be reliably positioned, and the CNC vertical lathe performs accurate and reliable turning processing, thereby ensuring the quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A three-dimensional diagram of an exhaust valve seat applicable to the present invention;

[0019] Figure 2 A three-dimensional diagram showing the positioning of the exhaust valve seat in a first positioning state corresponding to the present invention;

[0020] Figure 3 This is a three-dimensional diagram of positioning the exhaust valve seat in the second positioning state corresponding to the present invention;

[0021] Figure 4 for Figure 2 A cross-sectional view of

[0022] Figure 5 for Figure 3 A cross-sectional view of

[0023] Figure 6 A three-dimensional diagram of the present invention assembled to the exhaust valve seat in both positioning states;

[0024] The names corresponding to the serial numbers in the figure are as follows:

[0025] Base 10, bottom plate 11, upper convex positioning ring 12, positioning stop ring 121, radial positioning screw hole 13, center positioning screw hole 14, waste discharge groove 15, peripheral pressure attachment 20, support rod 21, upper convex positioning 211, movable pressure plate 22, first positioning hole 221, long slot hole 222, first screw rod 23, locking nut 24, concave pressure plate 30, center circular plate 31, center through hole 311, transition cone surface 32, upper pressure block 33, stop notch 331, second screw rod 40, upper nut 41, exhaust valve seat 50, outer stop ring surface 51, radial inner upper surface 52 of inner countersunk hole, upper convex outer ring surface 53, flat washer 60. DETAILED DESCRIPTION

[0026] A special device for finishing the exhaust valve seat, see Figure 1-Figure 6 , which includes a base 10, four sets of peripheral pressure attachments 20, a concave pressure plate 30, and a second screw 40;

[0027] The base 10 includes a bottom plate 11 and an upper convex positioning ring 12. A raised upper convex positioning ring 12 is provided at the center of the bottom plate 11. The upper convex positioning ring 12 is provided with a positioning stop ring 121. The stop ring 121 is provided in the shape of a stop ring surface 51 outside the valve face end of the exhaust valve seat 50. Four radial positioning screw holes 13 evenly distributed are respectively provided on the upper surface of the bottom plate 11 relative to the outer periphery of the upper convex positioning ring 12. A central positioning screw hole 14 is provided at the center of the upper surface of the bottom plate 11.

[0028] Each set of peripheral pressure attachments 20 includes a support rod 21, a movable pressure plate 22, a first screw rod 23, and a locking nut 24;

[0029] The concave pressure plate 30 includes a central circular plate 31, three transition cone surfaces 32, and three upper pressure blocks 33. The radial outer periphery of the central circular plate 31 is evenly distributed with three transition cone surfaces 32 expanding outward from bottom to top. A corresponding upper pressure block 33 is arranged on the top of each transition cone surface 32. The upper pressure block 33 is arranged to protrude radially outward. A stopper notch 331 is arranged on the lower surface of the radial outer end of the upper pressure block 33. The stopper notch 331 is arranged on the radial inner upper surface 52 of the inner countersunk hole located on the countersunk hole end surface of the exhaust valve seat 50.

[0030] The bottom of the exhaust valve seat 50 is positioned on the positioning stop ring 121;

[0031] It includes two positioning states. In the first positioning state, the movable pressure plates 22 of several groups of peripheral pressure accessories 20 press the convex outer ring surface 53 of the exhaust valve seat 50; in the second positioning state, the concave pressure plate 30 is pressed by the second screw 40, so that the upper pressure block 33 is positioned and pressed on the radial inner upper surface 52 of the inner countersunk hole of the exhaust valve seat 50 through the stop notch 331.

[0032] In specific implementation, the top of the support rod 21 is provided with an upper convex positioning 211, and the position of the movable pressure plate 22 corresponding to the upper convex positioning 211 is provided with a first positioning hole 221, and the movable pressure plate 22 is provided with a long slot hole 222 corresponding to the first screw rod 23, and the long slot hole 222 enables the movable pressure plate 22 to adjust the operation according to the actual position; when the peripheral pressure attachment 20 is in the assembled state, the upper convex positioning 211 of the top of the support rod 21 is inserted into the first positioning hole 221, the top of the first screw rod 23 passes through the long slot hole 222, and is threadedly connected with a locking nut 24, the bottom of the support rod 21 is arranged closely against the upper surface of the bottom plate 11, and the lower end of the first screw rod 23 is threadedly connected to the radial positioning screw hole 13, and the movable pressure plate 22 presses the upper convex outer ring surface 53 of the exhaust valve seat 50;

[0033] In the first positioning state, the support rod 21 is located radially outside the base plate 11 relative to the first screw rod 23 , which ensures that when the locking nut 24 is tightened, the inner end of the movable pressing plate 22 can reliably press against the convex outer annular surface 53 of the exhaust valve seat 50 .

[0034] The second screw rod 40 is provided with an upper nut 41, and the center circular plate 31 is provided with a center through hole 311. In the second positioning state, the second screw rod 40 passes through the center through hole 311 and is threadedly connected to the center positioning screw hole 14. The upper nut 41 is sleeved on the upper end of the second screw rod 40 and is pressed and connected to the upper surface of the center circular plate 31.

[0035] In a specific implementation, all first screw rods 23 and second screw rods 40 are equipped with flat washers 60, and the flat washers 60 are arranged under the corresponding nuts;

[0036] Four waste discharge grooves 15 are designed at the bottom of the upper convex positioning ring 12 of the base 10 for draining water and cuttings.

[0037] The processing method is divided into two steps:

[0038] The first step is to build the outer pressure plate: first, align the processed exhaust valve seat 50 so that the inner cone surface runout is ≤0.01 and the positioning surface is 0.02. The feeler gauge does not enter, and the first screw 23 is inserted into the radial positioning screw hole 13 of the bottom plate 11. The upper convex positioning 211 of the support rod 21 is screwed into the movable pressure plate 22. At the same time, the upper end of the first screw 23 passes through the long slot hole 222 of the movable pressure plate 22, and the inner end bottom of the movable pressure plate 22 is pressed against the upper convex outer ring surface 5 of the exhaust valve seat 50. 3. Use the locking nut 24 and the flat washer 60 to position and fix the exhaust valve seat 50 on the upper convex positioning ring 12 of the base 10. The wrench should apply force evenly to the four locking nuts 24. Then, semi-finish the countersink according to the requirements of the part drawing and leave a 0.25mm machining allowance on one side (due to the thin wall thickness of the countersink, there will be deformation after the pressure plate is loosened). Finish the bottom plane of the countersink, and measure and convert it with a depth micrometer to ensure that the distance between the bottom plane of the countersink and the positioning surface is controlled to the requirements of the part drawing;

[0039] The second step is to build the inner pressure plate: insert the second screw 40 into the central threaded hole 14 of the base 10, place the concave pressure plate 30, use the upper nut 41 and the flat washer 60 to fix the concave pressure plate 30 on the exhaust valve seat 50, and then remove the peripheral pressure attachment 20. The recovery exhaust valve seat 50 has been finely machined with an outer circle runout ≤0.01 and a positioning surface 0.02, and the feeler gauge cannot enter; the end plane and appearance of the exhaust valve seat 50 (including the outer circle, outer ring groove, annular arc surface, chamfers and fillets of each gear) are finely machined according to the drawing, and finally the inner hole sharp knife is used to finely machine the countersink and the root groove, and the inner diameter micrometer is used to detect the inner hole size. After the machining size is qualified, the second screw 40 and the concave pressure plate 30 are removed, and finally the three-coordinate measurement of size and shape and position tolerances is carried out.

[0040] The details of the device are as follows:

[0041] 1. Due to the large number of exhaust valve seat models, the base is designed to be simple in order to save the cost of opening the base mold;

[0042] 2. The outer circle of the boss on the valve face of the exhaust valve seat and its step surface have very high precision requirements. The upper convex positioning ring and the positioning stop ring of the base are used as positioning references to determine the size of the positioning hole and positioning surface of the base, and are used as key parts for designing the overall structure;

[0043] 3. Since the wall thickness of the exhaust valve seat countersink end is relatively thin, there is deformation after the pressure plate is released. It is necessary to use the processing method of first semi-finishing turning with the outer pressure plate, then changing to the inner pressure plate to fine-turn the end plane and appearance, and finally use the inner hole sharp tool to fine-turn the countersink and root cleaning groove. Considering the tool handle width, tool feed and retract distance, inner diameter micrometer measurement, pressing and avoiding height, etc. during countersink finishing, a concave pressure plate is designed after comprehensive analysis. The external dimensions are determined according to the above requirements to ensure the inner hole measurement distance, control height, and retract distance; at the same time, in order to improve the processing accuracy, enhance stability and adaptability, three evenly distributed notches are cut by wire cutting to design a concave triangular pressure plate;

[0044] 4. Due to the particularity of the exhaust valve seat material, iron cuttings are not easy to be discharged, which can easily cause scratches and scratches on the inner cavity. Four waste discharge grooves are designed at the bottom of the upper convex positioning ring of the base for drainage and cuttings;

[0045] 5. The clamping method of the outer pressure plate of the exhaust valve seat is designed to be symmetrically clamped by four movable pressure plates. The four symmetrical movable pressure plates can evenly distribute the clamping force, effectively prevent the workpiece from moving or deforming during processing, and always provide stability; the four symmetrical movable pressure plates make clamping and loosening the workpiece relatively simple, and improve work efficiency; the symmetrical clamping of the four movable pressure plates helps to reduce the error caused by uneven clamping of the workpiece, ensuring the processing accuracy and workpiece quality; this clamping method of four symmetrical pressure plates has strong applicability;

[0046] 6. The base is a casting support, and the material is HT200, which has good casting performance, good cutting performance, good vibration absorption performance, and good anti-friction and wear performance;

[0047] 7. The concave pressing plate is made of 45# steel, which is relatively cheap and practical, and has good mechanical properties after heat treatment and tempering;

[0048] 8. The peripheral pressure accessories use movable pressure plates, first screws and flat washers, mainly because of their strong practicality and the advantages of convenient and timely tightening and disassembly.

[0049] After adopting the structure of the present invention, the wall thickness of the countersunk end of the exhaust valve seat is relatively thin, and there is deformation after the pressure plate is released. It is necessary to adopt a processing method of first semi-finishing turning with an outer pressure plate, then changing to an inner pressure plate to fine-turn the end plane and appearance, and finally using an inner hole sharp knife to fine-turn the countersunk hole and the root cleaning groove. Therefore, the processing method is divided into two steps, and the bottom of the exhaust valve seat is positioned at the positioning stop ring arrangement; the positioning of the exhaust valve seat is also divided into two steps. The first step, that is, the first positioning state, a plurality of groups of movable pressure plates of the peripheral pressure accessories press the convex outer ring surface of the exhaust valve seat, and then the inner countersunk hole at the countersunk end is turned by a turning tool. In the second step, the inner countersunk hole is reliably positioned by the concave pressure plate, the peripheral pressure accessories are removed, and the end plane and the appearance of the countersunk hole end are turned by a turning tool, and finally the countersunk hole and the root cleaning groove are finely turned with an inner hole sharp knife; it enables the exhaust valve seat processed by step A to be reliably positioned, and the CNC vertical lathe performs accurate and reliable turning processing, thereby ensuring the quality of the product.

[0050] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and range of equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0051] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A special device for finishing the exhaust valve seat, characterized in that: It includes: The base comprises a bottom plate and an upper convex positioning ring, wherein a raised upper convex positioning ring is provided at the center of the bottom plate, and the upper convex positioning ring is provided with a positioning stop ring, and the stop ring is provided in the shape of an outer stop ring surface of the valve face end of the exhaust valve seat, and a plurality of radial positioning screw holes are respectively provided on the upper surface of the bottom plate relative to the outer periphery of the upper convex positioning ring; A plurality of sets of peripheral pressing accessories, each set of peripheral pressing accessories includes a support rod, a movable pressing plate, a first screw rod, and a locking nut; A concave pressure plate, comprising a central circular plate, a plurality of transition conical surfaces, and a plurality of upper pressure blocks, wherein the radial outer periphery of the central circular plate is provided with a plurality of transition conical surfaces expanding outward from bottom to top, and a corresponding upper pressure block is provided on the top of each transition conical surface, and the upper pressure block is arranged to protrude radially outward, and a stop notch is provided on the lower surface of the radial outer end of the upper pressure block, and the stop notch is provided on the radial inner upper surface of the inner countersunk hole located on the countersunk hole end surface of the exhaust valve seat; and a second screw; The bottom of the exhaust valve seat is positioned in a positioning stop ring arrangement; It includes two positioning states. In the first positioning state, a plurality of groups of movable pressure plates of the peripheral pressure attachments press the convex outer ring surface of the exhaust valve seat; in the second positioning state, the concave pressure plate is pressed by the second screw rod so that the upper pressure block is positioned and pressed on the radial inner upper surface of the inner countersunk hole of the exhaust valve seat through the stop notch.

2. A special device for finishing the exhaust valve seat according to claim 1, characterized in that: The top of the support rod is provided with an upper convex positioning, the position of the movable pressing plate corresponding to the upper convex positioning is provided with a first positioning hole, and the movable pressing plate is provided with a long slot hole corresponding to the first screw rod.

3. A special device for finishing the exhaust valve seat according to claim 2, characterized in that: When the peripheral pressure accessory is in the assembled state, the top convex positioning part of the support rod is inserted into the first positioning hole, the top of the first screw rod passes through the long slot hole and is threadedly connected with a locking nut, the bottom of the support rod is arranged tightly against the upper surface of the base plate, the lower end of the first screw rod is threadedly connected to the radial positioning screw hole, and the movable pressure plate presses the convex outer ring surface of the exhaust valve seat.

4. A special device for finishing the exhaust valve seat according to claim 3, characterized in that: In the first positioning state, the support rod is located radially outside the base plate relative to the first screw rod.

5. A special device for finishing the exhaust valve seat according to claim 1, characterized in that: The peripheral pressure attachment also includes a flat washer, and a flat washer is arranged between the locking nut and the movable pressure plate.

6. A special device for finishing the exhaust valve seat according to claim 1, characterized in that: The second screw rod is equipped with an upper nut, the center circular plate is provided with a center through hole, and the center of the upper surface of the bottom plate is provided with a center positioning screw hole. The second screw rod passes through the center through hole and is threadedly connected to the center positioning screw hole. The upper nut is sleeved on the upper end of the second screw rod and is pressed and connected to the upper surface of the center circular plate.

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