V12 engine cylinder block high-precision cylinder hole position degree control method

Abstract

The invention relates to a high-precision cylinder hole position degree control method for a V12 engine cylinder block. The method comprises the steps that non-uniform reduced scale design and integrated pipe barrel core design are adopted, reinforcing ribs are arranged in a riser cavity on the riser forming side of the integrated pipe barrel core, the reverse deformation amount is increased for the position of a pipe barrel, the precision of the integrated pipe barrel core is controlled, and a core assembly mode is designed. According to the method, the position degree of the cylinder hole of the cylinder body is controlled by controlling solidification and shrinkage of the aluminum alloy through the design of a non-uniform reduced scale, the influence of core assembly errors on the position degree of the cylinder body is reduced through the design of a core assembly mode, and the position precision of the cylinder hole is further improved through the control of the sand core precision and the design of the reverse deformation amount of the sand core.

Description

Technical Field

[0001] The invention belongs to the technical field of engine cylinder blocks and relates to a high-precision cylinder bore position control method for a V12 engine cylinder block. Background Art

[0002] The V12 aluminum alloy engine cylinder block has high requirements on the position of the cylinder bore, and the diameter affects the performance of the product.

[0003] If the cylinder bore position accuracy (i.e. the position accuracy of the cylinder bore) is too low, it will have many effects on the cylinder performance:

[0004] ① It will reduce the uniformity of the processed cylinder liner wall thickness, which will lead to a decrease in the durability of the cylinder block and an increase in the tendency to crack during long-term high-load operation; ② Increase the sealing of the water jacket holes between the cylinder holes; Therefore, the cylinder hole position often needs to be controlled within the range of ±0.5mm, and some products even require control within the range of ±0.35mm. For the inline four-cylinder cylinder block, the cylinder hole position is only affected by the dimensional errors in the x and y directions, while for the V-type cylinder block, the cylinder hole position is affected by the dimensional errors in the x, y, and z directions. The control difficulty is increased. Compared with the V6 and V8 cylinder blocks, the V12 cylinder block has more cylinder holes and a larger distance between the far-end cylinder holes, which further increases the difficulty of controlling the cylinder hole position.

[0005] Patent document CN109899172A discloses a V-type 12-cylinder cylinder block, comprising: a V-shaped top, the V-shaped top comprises a plurality of cylinders arranged in two left and right rows, the cylinders are provided with cylinder sleeves, wherein the angle between the left and right rows of cylinders is 90°; two bottoms, each bottom is provided with a plurality of U-shaped reinforcing ribs; and a plurality of V-shaped reinforcing plates, each V-shaped reinforcing plate is arranged between two adjacent cylinders, the V-shaped reinforcing plate extends along the width direction of the V-type 12-cylinder cylinder block to the inner wall of the V-type 12-cylinder cylinder block, and the height of the V-shaped reinforcing plate reaches the middle position of the cylinder sleeve; wherein, two crankcase ventilation channels are provided on the V-shaped reinforcing plate, the two crankcase ventilation channels are symmetrically arranged, the two crankcase ventilation channels are connected front and back along the crankshaft direction, the two crankcase ventilation channels are connected to each other, and each crankcase ventilation channel is respectively connected to the crankcase of each cylinder; an oil-gas separation structure cover plate is provided above the end of one of the crankcase ventilation channels. The above patent documents only involve the cylinder structure design, not the high-precision cylinder bore position control solution.

[0006] Patent document CN103121082A discloses a method for pouring a V8 cylinder casting, which adopts a core group pouring method and includes the following technical measures: 1) setting the casting pouring position; 2) setting the pouring system; 3) core group assembly; 4) pouring operation; Compared with the prior art, the present invention has the characteristics of relatively simple core group structure, high yield rate and low production cost. The above patent document is not about aluminum alloy cylinder, and does not involve aluminum alloy casting reduction, cylinder hole position control, etc.

[0007] Patent document CN103121083A discloses a V-type cylinder casting core splitting process. The V-type cylinder casting core splitting process adopts an overall surrounding core splitting, and the specific steps include: first, the V-type cylinder body is placed with the cylinder top facing downward and the machine foot facing upward, and the bottom surface and the outer side of the sand core are designed; then, the entire sand core is divided into a front insert core and a rear insert core and a plurality of main body sand cores located between the front insert core and the rear insert core through the core splitting line from the front end to the rear end of the V-type cylinder body; finally, a common push rod chamber sand core on each main body sand core is separately designed. The overall surrounding core splitting method is adopted, supplemented by sand core positioning measures, which reduces the number of sand cores, simplifies the mold manufacturing process, simplifies the external structure, facilitates the core lowering, and accurately positions the core lowering, and ensures the strength of the sand core, avoids deformation during circulation and casting, so as to improve production efficiency and save production costs. The above patent document is different from the analysis scheme of the present invention, and does not design non-uniform scaling, and does not design cylinder hole position accuracy measures. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the above-mentioned problems existing in the prior art and provide a high-precision cylinder bore position control method for a V12 engine cylinder block.

[0009] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0010] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions:

[0011] A high-precision cylinder bore position control method for a V12 engine cylinder block, characterized by comprising:

[0012] Adopt non-uniform scaling design: Based on the 8‰ - 10‰ scaling used for automotive castings, for the scaling in the cylinder bore arrangement direction, additionally increase the shrinkage coefficient a; the shrinkage of the casting in the area near the cylinder liner is restricted by the cylinder liner and no macroscopic shrinkage occurs, and the scaling of the inner wall of the cylinder block attached to the cylinder liner is 0; the scaling of the cylinder block is no longer the average value x, but is divided into the scaling in the X direction of the cylinder bore arrangement, the scaling in the Y and Z directions, and the scaling of the inner wall around the cylinder liner along the cylinder liner axis direction, and the proportional relationship among the three is: x, x(1 + a), 0.

[0013] Further, a = 0.8‰ - 1.2‰

[0014] A high-precision cylinder bore position control method for a V12 engine cylinder block further includes an integrated integrated tube core design: The core for fixing the cylinder liner and the core for forming a riser above the top surface of the casting are made into an integrated integrated tube core.

[0015] Further, add reinforcing ribs inside the riser cavity on the riser forming side of the integrated integrated tube core to increase the stiffness of the integrated integrated tube core and reduce the deformation of the integrated integrated tube core under the action of the gravity of the core and the attached cylinder liner and the hydraulic pressure of the aluminum alloy liquid during the filling and solidification process of the casting.

[0016] Further, add an anti-deformation amount to the tube position, and design the 6 cylinder bores of the integrated integrated tube cores on the left and right sides to be offset in sequence towards the cylinder block central axis direction, and the offset amounts of the 6 cylinder bores are: 0, b, 2b, 2b, b, 0.

[0017] Further, b = 0.05 - 0.2.

[0018] A high-precision cylinder bore position control method for a V12 engine cylinder block further includes integrated integrated tube core precision control: The error 丨ΔL丨 between the average actual measurement value L’ of the distance between the axes of the two outermost tubes of the integrated integrated tube core in each batch and the design theoretical value L0 is controlled to be ≤0.3mm. If 丨ΔL丨 > 0.3mm, add an anti-deformation amount on the core to offset the deviation of the cylinder bore distance.

[0019] A high-precision cylinder bore position control method for a V12 engine cylinder block further includes core assembly method design: First, fix the cylinder liner to each tube of the integrated integrated tube core through a cylinder liner assembly tooling, then assemble the integrated integrated tube core into the sand package. The integrated integrated tube core is fixed to the crankcase core through the core heads below the 6 tubes at the bottom. The crankcase core adopts a split design, that is, each tube corresponds to an independent crankcase core, to avoid the error between the core heads of each crankcase core acting on the tube core and affecting the cylinder bore precision; the integrated integrated tube core is fixed to the front core and the rear core through the core heads on both sides above, and then is pressed tightly by the upper cover core.

[0020] Further, the core assembly gap is 0.1 - 0.3mm.

[0021] A V12 engine cylinder block is manufactured using the high-precision cylinder bore position control method as described above.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention controls and realizes the precision requirement of the cylinder hole position of an aluminum alloy cylinder block by adopting a non-uniform scale design for the casting; reduces the influence of the core group error on the cylinder block position by designing the core group method; and further improves the position precision of the cylinder hole by controlling the sand core precision and designing the sand core reverse deformation amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings:

[0025] Figure 1 It is a schematic diagram of the various scale directions involved in the V12 cylinder block;

[0026] Figure 1 middle:

[0027] 1. V12 cylinder block;

[0028] 2. Cylinder bore;

[0029] 3. X direction (cylinder hole arrangement direction);

[0030] 4. Y direction;

[0031] 5. Z direction;

[0032] 6. Cylinder bore axis direction;

[0033] Figure 2 It is a schematic diagram of assembling the cylinder sleeve and the integrated tube core;

[0034] Figure 2 middle:

[0035] 1. Integrated tube core;

[0036] 2. Tube forming part;

[0037] 3. Riser forming part;

[0038] 4. Cylinder liner;

[0039] 5. The distance between the two farthest tube axes;

[0040] Figure 3 It is a schematic diagram of the integrated tube core assembly;

[0041] Figure 3 middle:

[0042] 1. Integrated tube core;

[0043] 2. Crankcase core;

[0044] 3. Crankcase core head;

[0045] 4. Front end core;

[0046] 5. Back-end chip;

[0047] 6. Integrated core heads at both ends of the tube core;

[0048] Figure 4 This is a flow chart of the high-precision cylinder bore position control method for a V12 engine cylinder block according to the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the implementation of the present invention clearer, the technical solution in the embodiment of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiment of the present invention.

[0050] In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The described embodiments are only some embodiments of the present invention, but not all embodiments.

[0051] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0052] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0053] The present invention is described in detail below in conjunction with the accompanying drawings:

[0054] The casting process of the V-type cylinder block can be simply divided into core making, core assembly, pouring, and solidification. These process steps all have an impact on the position of the cylinder bore of the V12 cylinder block.

[0055] The present invention is aimed at a V12 cylinder block with a core assembly process of an inlaid cylinder liner. In the process design stage, key links of the above-mentioned processes are specially designed to ensure the position accuracy of the cylinder bore of the cylinder block.

[0056] As Figure 4 shown, in the order considered in the process design, specific technical solutions for non-uniform scaling design, integrated tube core design, core assembly method design, reverse deformation design of tube position, and core accuracy control are proposed respectively.

[0057] Non-uniform scaling:

[0058] As Figure 1 , Figure 4 shown, the present invention provides a method for controlling the high-precision position degree of cylinder holes of a V12 engine block. Instead of using the conventional uniform scaling, the present invention adopts an original uniform scaling method according to the characteristics of the non-uniform shrinkage of the V12 engine block with inlaid cylinder liners. Based on the 8‰ - 10‰ scaling used for automotive castings, an additional shrinkage coefficient a is added in the scaling direction of the cylinder holes (a = 0.8‰ - 1.2‰. Taking the 10‰ scaling as an example, the scaling in the cylinder hole arrangement direction is 10.8‰ - 11.2‰); while the shrinkage of the casting in the area near the cylinder liner is restricted by the cylinder liner and no macroscopic shrinkage occurs. Therefore, the scaling of the inner wall of the cylinder block attached to the cylinder liner is 0. Therefore, the scaling of the engine block is no longer the average value x, but is divided into the scaling in the cylinder hole arrangement direction (X direction), the scaling in the other two directions (Y direction and Z direction), and the scaling of the inner wall of the area around the cylinder liner along the axis direction of the cylinder liner. The proportional relationship among the three is: x, x(1 + a), 0.

[0059] Integrated tube core design:

[0060] As Figure 2 shown, the sand core for fixing the cylinder liner and the sand core for forming a riser above the top surface of the casting are made into an integrated tube core to eliminate the core assembly error caused by the split tube core. And reinforcing ribs are added inside the riser cavity on the riser forming side of the integrated tube core to increase the stiffness of the integrated tube core and reduce the deformation of the integrated tube core under the action of the gravity of the sand core and the attached cylinder liner and the hydraulic pressure of the aluminum alloy liquid during the filling and solidification process of the casting. And, for the deformation of the integrated tube core that still exists, an additional reverse deformation amount is added to the tube position, and a design is made to offset the 6 cylinder holes of the integrated tube cores on the left and right sides towards the cylinder block central axis direction in sequence. The offset amounts of the 6 cylinder holes are: 0, b, 2b, 2b, b, 0, where b = (0.05 - 0.2).

[0061] Integrated tube core accuracy control:

[0062] The error |ΔL| between the actual measured average value L' of the distance between the axes of the two outermost tubes of the integrated tube core in each batch and the design theoretical value L0 should be controlled within ≤0.3mm. If |ΔL| > 0.3mm, the deviation of the cylinder tube distance should be offset by adding an additional reverse deformation amount to the sand core.

[0063] Core assembly design:

[0064] like Figure 3 As shown, the cylinder sleeve is first fixed to each tube of the integrated tube core through the cylinder sleeve assembly tool, and then the integrated tube core is assembled into the sand bag. The lower part of the integrated tube core is fixed to the crankcase core through the core heads under the 6 tubes. The crankcase core adopts a split design, that is, each tube corresponds to an independent crankcase core to avoid the error between the core heads of each crankcase core acting on the tube core and affecting the cylinder bore accuracy; the upper part of the integrated tube core is fixed to the front core and the rear core through the core heads on both sides, and then pressed by the upper large cover core. In order to ensure the core assembly accuracy of the sand core, the core assembly gap (usually 0.1-0.3mm) is controlled as low as possible according to the production conditions.

[0065] The sand core forming each tube and the sand core forming the riser are designed to be an integrated sand core; when assembling the core, the cylinder sleeve is first assembled on the tube of the integrated tube core and fixed by interference fit.

[0066] The present invention provides a V12 engine cylinder block, which is manufactured by adopting the above-mentioned high-precision cylinder bore position control method.

[0067] The effect of aluminum alloy solidification shrinkage on cylinder block position accuracy is controlled by non-uniform scaling design, the influence of core group error on cylinder block position accuracy is reduced by core group design, and the position accuracy of cylinder hole is further improved by controlling sand core accuracy and designing sand core reverse deformation.

[0068] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the present invention and within the spirit and principle of the present invention shall be covered within the protection scope of the present invention. At the same time, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A high precision cylinder bore position control method for a V12 engine cylinder block, characterized in that: Including: Adopting non-uniform scaling design: Based on the 8‰ - 10‰ scaling used for automotive castings, an additional shrinkage coefficient a is added to the scaling in the cylinder bore arrangement direction; the shrinkage of the casting in the area near the cylinder liner is restricted by the cylinder liner and no macroscopic shrinkage occurs, and the scaling of the inner wall of the cylinder block attaching the cylinder liner is 0; the scaling of the cylinder block is no longer the average value x, but is divided into the scaling in the X direction of the cylinder bore arrangement, the scaling in the Y and Z directions, and the scaling of the inner wall of the area around the cylinder liner along the cylinder liner axis direction, and the proportional relationship among the three is: x, x(1 + a), 0.

2. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 1, characterized in that: a＝0.8‰～1.2‰。 3. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 1, characterized in that: It also includes an integrated integrated tube core design: The sand core for fixing the cylinder liner and the sand core forming a riser above the top surface of the casting are made into an integrated integrated tube core.

4. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 3, characterized in that: Reinforcing ribs are added inside the riser cavity on the riser forming side of the integrated tube core to increase the stiffness of the integrated tube core and reduce the deformation of the integrated tube core under the action of the gravity of the sand core and the attached cylinder liner and the hydraulic pressure of the aluminum alloy liquid during the filling and solidification process of the casting.

5. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 3, characterized in that: An anti-deformation amount is added to the tube position, and a design is made in which the 6 cylinder bores of the integrated tube cores on the left and right sides are sequentially offset towards the cylinder block central axis direction, and the offset amounts of the 6 cylinder bores are: 0, b, 2b, 2b, b, 0.

6. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 5, characterized in that: b＝0.05～0.2。 7. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 1, characterized in that: It also includes integrated integrated tube core accuracy control: The error 丨ΔL丨 between the actual measured average value L’ of the distance between the axes of the two outermost tubes of the integrated integrated tube core in each batch and the design theoretical value L0 is controlled to be ≤0.3mm. If 丨ΔL丨 > 0.3mm, an anti-deformation amount is added to the sand core to offset the deviation of the cylinder bore distance.

8. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 1, characterized in that: It also includes core assembly method design: First, the cylinder liner is fixed to each tube of the integrated tube core through a cylinder liner assembly tooling, and then the integrated tube core is assembled into the sand package. The lower part of the integrated tube core is fixed to the crankcase core through the core heads under 6 tubes. The crankcase core adopts a split design, that is, each tube corresponds to an independent crankcase core, avoiding the error between the core heads of each crankcase core from acting on the tube core and affecting the cylinder bore accuracy; the upper part of the integrated tube core is fixed to the front core and the rear core through the core heads on both sides, and then is pressed tightly by the upper cover core.

9. A method for controlling the high-precision position of cylinder bores of a V12 engine cylinder block according to claim 8, characterized in that: The core assembly gap is 0.1 - 0.3mm.

10. A V12 engine cylinder block, characterized in that: The high-precision cylinder hole position control method according to any one of claims 1 to 9 is used for manufacturing.

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