Grinding wheel and device for machining closed gap of piston ring

Abstract

The grinding wheel comprises a grinding wheel body, a mounting section, a chamfering section and a cutting section are sequentially formed on the grinding wheel body from the circle center to the outside in the diameter direction, and the chamfering section is composed of a chamfering face with the included angle beta between the two faces. The cutting section is composed of two cutting surfaces with an included angle of alpha, and alpha < lt >; beta; an annular groove is formed in the intersection of the cutting surface and the chamfering surface; meanwhile, the utility model discloses a device for machining the closed gap of the piston ring, the device comprises a die sleeve, a ring gauge and a grinding wheel body, and a die sleeve cavity is formed in the die sleeve. The annular groove is formed between the chamfering section and the cutting section of the grinding wheel, the density of electromagnetic wires at the annular groove is increased, nickel base deposition at the position is increased, the carborundum bonding strength of the position is improved, meanwhile, the annular groove can discharge metal chips generated by cutting, heat dissipation is improved, and the service life of the grinding wheel is prolonged. The service life of the grinding wheel is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of piston ring processing, in particular to a grinding wheel and a device for processing the closed gap of a piston ring. Background Art

[0002] The diesel engine compresses air in the cylinder to generate high-temperature and high-pressure gas, and then sprays atomized diesel for combustion and expansion. The expanded compressed gas pushes the crank-connecting rod mechanism to output power. Therefore, if you want to increase the power of the diesel engine, you need to increase the temperature and pressure of the compressed gas, and then increase the expansion rate and multiple of the compressed gas after the sprayed atomized diesel is burned, increase the instantaneous explosion pressure, and the crank-connecting rod mechanism obtains greater driving force. The crank-connecting rod mechanism includes a reciprocating piston, a piston ring for sealing the gap between the piston and the cylinder wall, and other components. Considering that the piston ring will expand thermally, a closed gap is usually cut in the axial direction of the piston ring, so that the piston ring with a radius slightly larger than the inner radius of the cylinder will not get stuck on the inner wall of the cylinder when it moves up and down relative to the cylinder. The closed gap positions of multiple piston rings are usually staggered at a certain angle along the circumference, so as to obtain a longer maze-like leakage route in the cylinder, increase the leakage resistance, and reduce the leakage amount. However, for high-power and high-explosion-pressure diesel engines, the excessive impact force after the compressed gas burns and expands will cause multiple piston rings to be subjected to excessive external force in the axial direction of the piston, which will cause the piston rings to move up and down relative to the piston, resulting in a reduction in the sealing effect of the piston rings and affecting the overall functional performance of the engine. The existing solution is to increase the closed gap width from less than 1.0 mm to more than 3.0 mm, thereby increasing the amount of leakage and removing some of the impact force.

[0003] The existing technology for processing the closed gap of the piston ring usually adopts grinding wheel cutting. The grinding wheel is divided into a mounting section, a chamfering section and a cutting section from the center of the circle in the radial direction outward. The closed gap of the piston ring after cutting usually includes two opposite opening surfaces and two chamfered surfaces where the upper surface and the opening surface intersect. The process of grinding wheel cutting the closed gap of the piston ring is: first cut the piston ring opening surface through the cutting section, then grind the chamfered surface through the chamfering section, and finally smooth the opening surface of the cutting section. Figure 6 As shown in the figure, the grinding wheel is processed by nickel-based electroplating CBN process. The electromagnetic wire density at the intersection of the cutting section and the chamfering section is low, and the current passing through during electroplating is small, resulting in less nickel-based deposition, so that the bonding strength of the diamond grains in the transition section is low; at the same time, in order to improve the efficiency of the grinding wheel in processing large-sized closed gaps, the processing volume of the grinding wheel is greater than that of small-sized closed gaps, so that the cutting section and the chamfering section need to process the piston ring at the same time. The contact area between the piston ring and the chamfering section is large, and the friction heat is large, which leads to poor chip removal and easy formation of built-up edge, aggravating the wear of diamond grains, thereby causing serious wear at the intersection of the chamfering section and the cutting section of the grinding wheel, reducing the service life of the grinding wheel. Summary of the invention

[0004] The utility model solves the problem of reduced service life of a grinding wheel for machining a large-size closed gap of a piston ring, and provides a grinding wheel and a device for machining the closed gap of a piston ring. The specific technical scheme is as follows:

[0005] A grinding wheel for machining a closed gap of a piston ring comprises a grinding wheel body, wherein the grinding wheel body is formed with a mounting section, a chamfering section and a cutting section in sequence from the center of a circle to the outside in a diameter direction, wherein the mounting section is composed of two parallel mounting surfaces, wherein the mounting surfaces are symmetrical about the middle surface of the mounting section, and the mounting section, the chamfering section and the cutting section are concentric, wherein the chamfering section is composed of two chamfering surfaces with an included angle of β, wherein an opening of the chamfering surface is close to the mounting section; wherein the cutting section is composed of two cutting surfaces with an included angle of α, wherein an opening of the cutting surface is close to the chamfering section, and α<β; and wherein an annular groove is provided at the intersection of the cutting surface and the chamfering surface, wherein an axial cross section of the annular groove is an arc concave toward the middle surface.

[0006] Furthermore, the radius of the annular groove is R1, 0.125≤R1≤0.57, the distance between the points where the cutting section and the chamfering section intersect with the annular groove is A, 0.2≤A≤0.9, and the distance from the bottom of the annular groove to the intersection of the annular groove and the cutting section is B, 0.05≤B≤0.2.

[0007] Furthermore, the chamfering section consists of two chamfering surfaces with an angle of β, which are symmetrical about the middle plane, 40°≤β≤50°; the cutting section consists of two cutting surfaces with an angle of α, which are symmetrical about the middle plane, 0°≤α≤0.5°.

[0008] Preferably, the annular groove is symmetrical about the middle plane, and the chamfered section and the cutting section are both symmetrical about the middle plane.

[0009] Secondly, a device for processing the closed gap of a piston ring includes: a die sleeve, the die sleeve is provided with a die sleeve side wall, and the die sleeve side wall has a cutting groove formed in the axial direction; a ring gauge, the ring gauge is provided with a ring gauge side wall, and the ring gauge side wall has a measuring groove formed in the axial direction; and a grinding wheel body capable of passing through the cutting groove, a die sleeve cavity is formed inside the die sleeve, and the radius of the die sleeve cavity is R2, and a ring gauge cavity is formed inside the ring gauge, and the radius of the ring gauge cavity is R3, R2>R3.

[0010] It can be seen from the above technical solution that the utility model has the following beneficial effects:

[0011] The utility model provides an annular groove between the chamfering section and the cutting section of the grinding wheel. The density of the electromagnetic wire at the annular groove is increased compared with the previous one, so that the nickel-based deposition here is increased, and the diamond grain bonding strength at this part is improved. At the same time, the annular groove can discharge the metal chips generated by cutting, increase heat dissipation, and improve the service life of the grinding wheel; secondly, when the closed gap is greater than 3.0mm, the grinding wheel angle α is set between 0-0.5°, so that the large-size closed gap shape obtained by the grinding wheel cutting meets the industry requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the structure of an embodiment of the utility model device;

[0013] Figure 2 The first piston ring processed by the device of the utility model and its partial enlarged view, the second piston ring and its partial enlarged view;

[0014] Figure 3 It is a cross-sectional view and a partial enlarged view of the grinding wheel of the utility model;

[0015] Figure 4 This is the distribution diagram of the electromagnetic wires of the grinding wheel of the utility model;

[0016] Figure 5 This is an illustration of the utility model ring gauge measuring the second closed gap;

[0017] Figure 6 This is the distribution diagram of the electromagnetic wire of a conventional grinding wheel.

[0018] In the figure: 1, grinding wheel body; 2, die sleeve; 3, ring gauge; 4, piston ring; 11, cutting section; 12, chamfering section; 13, annular groove; 14, mounting section; 21, die sleeve cavity; 22, die sleeve side wall; 23, cutting groove; 31, ring gauge cavity; 32, ring gauge side wall; 33, measuring groove; 41, first piston ring; 42, first closed gap; 43, second piston ring; 44, second closed gap. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] In the description of the embodiments of the present invention, it should be noted that the terms "inside", "outside", "upper", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] like Figure 1 As shown in a, the embodiment of the utility model is to set the grinding wheel body 1 inside the die sleeve 2 to process the closed gap of the piston ring 4. Figure 1 As shown in b, the shape of the large-sized closed gap processed is then measured inside the ring gauge 3 to see whether it meets the standard requirements of the piston ring 4 industry.

[0022] The embodiment of the utility model includes a grinding wheel body 1, which is formed with a mounting section 14, a chamfering section 12 and a cutting section 11 in sequence from the center of a circle along the diameter direction outward, the mounting section 14 is composed of two parallel mounting surfaces, the mounting surfaces are symmetrical about the middle surface of the mounting section 14, the mounting section 14, the chamfering section 12 and the cutting section 11 are concentric, the chamfering section 12 is composed of chamfering surfaces with an angle β between the two surfaces, and the opening of the chamfering surface is close to the mounting section 14; the cutting section 11 is composed of cutting surfaces with an angle α between the two surfaces, and the opening of the cutting surface is close to the chamfering section 12, α<β; and an annular groove 13 is provided at the intersection of the cutting surface and the chamfering surface, and the axial cross-section of the annular groove 13 is an arc concave toward the middle surface.

[0023] Specifically, the grinding wheel body 1 is a disc with multiple different thicknesses, and the disc is symmetrical about the middle surface of its own axis. This design ensures that during the process of the cutting segment 11 processing the piston ring 4, the opening surface of the piston ring 4 processed by the cutting surface is also symmetrical about the middle surface. The symmetrical middle surface ensures that after the piston ring 4 is placed in the ring gauge 3, the opening surface is also symmetrical about the middle surface, which can improve the accuracy of detecting the closed gap. α<β enables the chamfering segment 12 to process the chamfered surface of the piston ring 4 while the cutting segment 11 processes the opening surface of the piston ring 4. The annular groove 13 reduces the contact area between the chamfering segment 12 and the cutting segment 11 and the piston ring 4 when the cutting segment 11 processes the piston ring 4, thereby reducing the heat generated by friction. Secondly, the annular groove 13 can discharge metal iron filings generated by the processing.

[0024] like Figure 2As shown in the figure, the die sleeve 2 is formed with a die sleeve cavity 21 having an inner wall radius of R2 and a side wall 22 of the die sleeve. The side wall 22 of the die sleeve is formed with a cutting groove 23 in its axial direction. A grinding wheel body 1 is placed in the cutting groove 23. The cutting section 11 and the chamfering section 12 of the grinding wheel body 1 process the piston ring 4 in the die sleeve cavity 21 to form a first piston ring 41. A first closed gap 42 is formed at the position of the first piston ring 41 corresponding to the cutting groove 23. The outer wall radius of the first piston ring 41 is R4, where R4 = R2. The inner wall of the die sleeve cavity 21 is in close contact with the outer wall of the first piston ring 41, so that when the grinding wheel body 1 processes the first closed gap 42 of the first piston ring 41 through the cutting groove 23, the position of the first piston ring 41 relative to the cutting groove 23 will not change.

[0025] Secondly, the ring gauge 3 is formed with a ring gauge cavity 31 having an inner wall radius of R3 and a side wall 32 of the ring gauge. The side wall 32 of the ring gauge is formed with a measuring groove 33 in its axial direction. A second piston ring 43 is arranged inside the ring gauge cavity 31. The outer peripheral radius of the second piston ring 43 is R5, where R5 = R3 < R2. The inner wall of the ring gauge cavity 31 is in close contact with the outer wall of the second piston ring 43, which can simulate the actual mating situation when the second piston ring 43 is placed in the cylinder. The close contact between the second piston ring 43 and the inner wall of the cylinder can reduce the air leakage during the up and down movement of the piston on the inner wall of the cylinder. A second closed gap 44 is formed in the axial direction of the second piston ring 43. The second piston ring 43 is formed by compressing the first piston ring 41 placed in the ring gauge cavity 31, and the second closed gap 44 is formed by compressing the first closed gap 42.

[0026] Figure 2 a and Figure 2 b are partial enlarged views of the first piston ring 41 and the first closed gap 42. As shown in the above figures, the radius of the die sleeve cavity 21 is R2, the outer circle radius of the first piston ring 41 is R4, and R2 = R4. Secondly, the widest distance H between the widest part of the first closed gap 42 and the cutting section 11 is the same, and half of the angle formed by the widest part of the first closed gap 42 and the center of the first piston ring 41 is θ1.

[0027] Figure 2 c and Figure 2 d are partial enlarged views of the second piston ring 43 and the second closed gap 44. As shown in the above figures, the radius of the ring gauge cavity 31 is R3, the outer circle radius of the second piston ring 43 is R5, and R3 = R5. The wall thickness of the side wall 32 of the ring gauge is T. Secondly, the widest part of the second closed gap 44 is S1, the narrowest part is S2, and half of the angle formed by the widest part of the second closed gap 44 and the center of the ring gauge 3 is θ2.

[0028] It is stipulated that ΔS = S2 - S1, and the range of ΔS of the qualified piston ring 4 is 0 - 0.1 mm, that is, S2 ≥ S1, commonly known as the inner eight - character opening. Combining the graphic geometric formula, the following formula is obtained:

[0029] △S=2*(tan(atan(0.5H / R4)-atan(0.5S1 / R5)-α)*T)

[0030] Note that this formula is applicable to S1 ≥ 3.0 mm. When S1 is less than 3 mm, the second piston ring 43 is unqualified.

[0031] From the formula, we know that when R4=68.3mm, R5=67.5mm, H=4.8mm, S1=3.5mm, T=5mm, the size of △S is related to α. The specific correlation is shown in the following table:

[0032]

[0033] The table shows that α gradually decreases from 1.5° to 0°, causing △S to increase from -0.17mm to 0.09mm, and the second closed gap 44 changes from not meeting the industry requirements to meeting the industry requirements. Therefore, 0°≤α≤0.5°, △S>0, meets the requirements, but the smaller the angle α of the cutting section 11, the closer the two sides of the cutting section 11 are to parallelism, and the more parallel the angle between the two machined surfaces of the closed gap is. The processed piston ring 4 is placed in the ring gauge 3, the outer and inner surfaces of the piston ring 4 are compressed respectively, the more parallel the angle between the two machined surfaces of the closed gap is, and the shape of the large-sized closed gap is more in line with the industry requirements of the piston ring 4. When α=0°, △S=0.09mm, so that R2 and R3 can take larger values, and then the piston ring 4 with a larger closed gap is processed.

[0034] like Figure 3 As shown, further, the radius of the annular groove 13 is R1, 0.125≤R1≤0.57, the distance between the points where the cutting section 11 and the chamfered section 12 intersect with the annular groove 13 is A, 0.2≤A≤0.9, and the distance from the bottom of the annular groove 13 to the intersection with the cutting section 11 is B, 0.05≤B≤0.2.

[0035] Specific, combined Figure 3 , Figure 4 and Figure 6As shown, the size of R1 is related to the electromagnetic wire distribution of the grinding wheel body 1 and the chip removal ability of the grinding wheel body 1. The annular groove 13 increases the nickel-based deposition here and the diamond bonding strength. At the same time, the annular groove 13 can provide a discharge channel for the metal chips cut by the grinding wheel to cut the first piston ring 41, avoiding the occurrence of built-up edge, and the annular groove 13 can reduce the contact area between the grinding wheel body 1 and the piston ring 4 when the cutting section 11 and the chamfering section 12 are processing the closed gap, thereby reducing the friction heat of the grinding wheel body 1, thereby increasing the service life of the grinding wheel. When R1<0.125, the electromagnetic wire distribution of the grinding wheel body 1 is similar to that of the conventional grinding wheel, and its nickel-based deposition is less, the diamond bonding strength is lower, and the chip removal ability of the annular groove 13 under this value is weak, and the service life of the grinding wheel under this value is about 10,000 pieces; when R1>0.57, the bonding strength between the cutting section 11 and the chamfering section 12 of the grinding wheel body 1 decreases, which reduces the service life of the grinding wheel. The inventor of the present application obtains the corresponding service life of the grinding wheel by setting different R1, A and B.

[0036]

[0037] The table shows the relationship between the annular grooves 13 of different sizes and the service life of the grinding wheel. It can be seen from the table that the service life of the closed gap machined by a conventional grinding wheel is 10,000 pieces, which represents the number of piston rings 4 that can be machined by the grinding wheel. Among them, A increases from 0.2 to 2, B increases from 0.05 to 0.3, and R1 increases from 0.125 to 1.1817, and it is concluded that the service life of the grinding wheel increases from 12,000 pieces to 31,000 pieces, and then decreases to 2.1. Therefore, when 0.16≤R1≤0.57, 0.3≤A≤0.9, and 0.1≤B≤0.2, the service life of the grinding wheel is maintained at more than 20,000 pieces. The value within this range balances the processing range and service life of the grinding wheel. Secondly, the smaller the processing range, the higher the processing cost of a single grinding wheel; when A=0.3, B=0.1, and R1=0.163, the service life of the grinding wheel body 1 is the highest, and its processing cost is the highest, which is 31,000 pieces.

[0038] Combination Figure 5 As shown, the steps of machining the closed gap of the piston ring 4 by the device of the utility model are as follows:

[0039] S1: The grinding wheel processes the first piston ring 41 and the first closed gap 42 through the cutting groove 23, the grinding wheel cutting section 11 processes the opening surface of the first closed gap 42, and the chamfering section 12 of the grinding wheel body 1 processes the chamfered surface of the first closed gap 42, and the chamfered surface intersects with the outer cylindrical surface of the first piston ring 41;

[0040] S2: The first piston ring 41 is placed into the ring gauge cavity 31 to obtain the second piston ring 43, the first closed gap 42 is compressed to obtain the second closed gap 44, and the outer cylindrical surface is still placed upward;

[0041] S3: Use a light source to project the second piston ring 43 and the second closed gap 44 onto the bottom surface of the ring gauge 3, and measure the minimum distance value in the projection of the second closed gap 44 as the gap detection result.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0043] The technology, shape and structure parts not described in detail in the present invention are all known technologies.

Claims

1. A grinding wheel for machining a closed gap of a piston ring, comprising a grinding wheel body (1), wherein the grinding wheel body (1) is formed with a mounting section (14), a chamfering section (12) and a cutting section (11) in sequence from the center of a circle along a diameter direction outward, wherein the mounting section (14) is composed of two parallel mounting surfaces, wherein the mounting surfaces are symmetrical about a middle surface of the mounting section (14), and the mounting section (14), the chamfering section (12) and the cutting section (11) are concentric, and wherein: The chamfered section (12) is composed of two chamfered surfaces with an included angle of β, and the opening of the chamfered surface is close to the mounting section (14); The cutting section (11) is composed of two cutting surfaces with an included angle of α, the opening of the cutting surface is close to the chamfered section (12), α<β; and An annular groove (13) is provided at the intersection of the cutting surface and the chamfered surface, and the axial cross section of the annular groove (13) is an arc that is concave toward the middle surface.

2. The grinding wheel according to claim 1, characterized in that: The radius of the annular groove (13) is R1, 0.125≤R1≤0.57, the distance between the points where the cutting section (11) and the chamfered section (12) intersect with the annular groove (13) is A, 0.2≤A≤0.9, and the distance between the bottom of the annular groove (13) and the intersection point of the annular groove (13) and the cutting section (11) is B, 0.05≤B≤0.

2.

3. The grinding wheel according to claim 1, characterized in that: The radius of the annular groove (13) is R1, 0.163≤R1≤0.57, the distance between the points where the cutting section (11) and the chamfered section (12) intersect with the annular groove (13) is A, 0.3≤A≤0.9, and the distance between the bottom of the annular groove (13) and the intersection point of the annular groove (13) and the cutting section (11) is B, 0.1≤B≤0.

2.

4. The grinding wheel according to claim 1, characterized in that: The radius of the annular groove (13) is R1, R1=0.163, the distance between the points where the cutting section (11) and the chamfered section (12) intersect with the annular groove (13) is A, A=0.3, and the distance between the bottom of the annular groove (13) and the intersection point of the annular groove (13) and the cutting section (11) is B, B=0.

1.

5. The grinding wheel according to claim 1, characterized in that: The chamfered section (12) is composed of two chamfered surfaces with an included angle of β, the chamfered surfaces are symmetrical with respect to the middle surface, and 40°≤β≤50°; The cutting section (11) is composed of two cutting surfaces with an included angle of α, the cutting surfaces are symmetrical with respect to the middle surface, and 0°≤α≤0.5°.

6. The grinding wheel according to claim 1, characterized in that: The chamfered section (12) is composed of two chamfered surfaces with an included angle of β, the chamfered surfaces are symmetrical with respect to the middle surface, and β=45°; and The cutting section (11) consists of two cutting surfaces with an included angle of α, the cutting surfaces are symmetrical with respect to the middle surface, and α=0°.

7. The grinding wheel according to claim 1, characterized in that: The annular groove (13) is symmetrical with respect to the middle surface, and the chamfering section (12) and the cutting section (11) are both symmetrical with respect to the middle surface.

8. A device for machining the closed gap of a piston ring, characterized in that: include: A mold sleeve (2), the mold sleeve (2) being provided with a mold sleeve side wall (22), and a cutting groove (23) being formed in an axial direction of the mold sleeve side wall (22); A ring gauge (3), the ring gauge (3) being provided with a ring gauge side wall (32), the ring gauge side wall (32) being formed with a measuring groove (33) in the axial direction; and A grinding wheel body (1) as claimed in any one of claims 1 to 7, capable of passing through the cutting groove (23).

9. The device according to claim 8, characterized in that: A mold sleeve cavity (21) is formed inside the mold sleeve (2), and the radius of the mold sleeve cavity (21) is R2. A ring gauge cavity (31) is formed inside the ring gauge (3), and the radius of the ring gauge cavity (31) is R3, where R2>R3.

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