Machining tool and machining method for receding chamfer reaming face of connecting rod of engine cylinder block

Abstract

The invention discloses a machining tool and a machining method for a connecting rod receding chamfer countersink face of an engine cylinder block. The machining tool comprises a tool handle, and a countersink face machining tool used for machining the connecting rod receding countersink face of the engine cylinder block and a chamfer machining tool used for machining a connecting rod receding chamfer of the engine cylinder block are coaxially fixed to the tool handle. An axial distance and a radial distance exist between the cutting edge of the spot facing machining tool and the cutting edge of the chamfer machining tool; the cutter handle can be installed on a machine tool main shaft, the cutter handle is driven by the machine tool main shaft to enable the reaming face machining cutter and the chamfering machining cutter to sequentially reach the machining position of the connecting rod receding reaming face and the machining position of the connecting rod receding chamfering respectively, and the connecting rod receding reaming face and the connecting rod receding chamfering are machined. The spot facing machining tool and the chamfering machining tool are integrated on the same tool handle and driven by the machine tool main shaft, so that the two tools can reach the corresponding machining positions in sequence, and one-time machining of the receding spot facing and the receding chamfering is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile manufacturing and processing, and particularly to a processing tool and a processing method for counterboring and chamfering the clearance of a connecting rod of an engine cylinder block. Background Art

[0002] In the power transmission system of an engine, as a key component, the smoothness of the movement path of the connecting rod is directly related to the operating reliability of the engine. To avoid interference wear between the connecting rod and the side wall of the cylinder hole of the engine cylinder block during the movement of the connecting rod, resulting in engine operation failure, the existing engine structures usually design clearance counterbores (as shown in Figure 2 ) and semi-circular clearance chamfers (as shown in Figure 3 ) on the side of the cylinder hole of the cylinder block to ensure the safe and stable movement of the connecting rod.

[0003] Currently, when machining the clearance surface and chamfer of the connecting rod of the engine cylinder block on a CNC machining center, the commonly used method is to use a vertical milling cutter or a counterboring cutter for surface machining, and a non-standard milling cutter with inserted blades for semi-circular chamfer machining. With good versatility, this machining method can adapt to various types of fixtures, workpieces, and machining processes. However, there are still many problems to be solved in this machining method. In terms of machining efficiency, its machining process is tool change - the tool moves to the surface machining position for machining - returns to the origin - tool change - the tool moves to the chamfering position for machining - returns to the origin - tool change. The cumbersome tool change and axis movement steps result in low machining efficiency during the machining process, seriously affecting the process rhythm. In the context of the popularization of automated production lines, insufficient process rhythm will significantly reduce the output efficiency of the entire line. From the cost perspective, the existing tool styles and machining methods require two strong self-locking tool holders, and the strength of the blades used for chamfering is insufficient (service life < 2000 units). Frequent tool changes increase the cost of the machining parts significantly. In addition, due to the low tool life under the existing machining method, frequent tool change operations not only increase the non-fault loss of equipment downtime but also bring safety risks to personnel and equipment.

[0004] Therefore, it is urgent to develop a machining technology for the clearance surface and chamfer of the connecting rod of the engine cylinder block that can overcome the above defects. Summary of the Invention

[0005] The object of the present invention is to solve the deficiencies of the above background art, and provide a processing tool and a processing method for counterboring and chamfering the clearance of a connecting rod of an engine cylinder block, which do not require frequent tool change operations, can complete the counterboring of the clearance surface and the clearance chamfering in one go, and have high strength of the chamfering processing blades.

[0006] To achieve this purpose, the machining tool for the clearance chamfering and counterboring of the connecting rod of the engine block designed by the present invention includes a tool shank. A counterboring tool for machining the clearance counterbored surface of the connecting rod of the engine block and a chamfering tool for machining the clearance chamfer of the connecting rod of the engine block are coaxially fixed on the tool shank. There is an axial distance and a radial distance between the cutting edge of the counterboring tool and the cutting edge of the chamfering tool. The tool shank can be installed on the machine tool spindle, and the tool shank is driven by the machine tool spindle to make the counterboring tool and the chamfering tool reach the machining positions of the clearance counterbored surface of the connecting rod and the clearance chamfer of the connecting rod respectively, and machine the clearance counterbored surface of the connecting rod and the clearance chamfer of the connecting rod.

[0007] Further, a tool mounting hole is axially opened in the middle of the end of the tool shank away from its installation on the machine tool spindle, and the counterboring tool is coaxially inserted and detachably fixed in the tool mounting hole.

[0008] Further, the chamfering tool includes a plurality of chamfering blades fixed at intervals along the circumference of the end of the tool shank away from its installation on the machine tool spindle.

[0009] Further, the chamfering blades are detachably fixed on the tool shank.

[0010] Further, a pressing plate for pressing the side of the chamfering blade away from the counterboring tool against the tool shank is also detachably fixed on the end of the tool shank away from its installation on the machine tool spindle.

[0011] Further, the chamfering blade is a multi-edge, cemented carbide blade, and its surface is coated with a nitride coating with a thickness of not less than 3.18 mm.

[0012] Further, the counterboring tool is made of hard alloy steel, and the tool shank is made of high-speed steel.

[0013] Even further, a machining method based on the above-mentioned machining tool for the clearance chamfering and counterboring of the connecting rod of the engine block includes installing the tool shank on the machine tool spindle; according to the machining parameters of the clearance counterbored surface of the connecting rod, driving the tool shank by the machine tool spindle to move the counterboring tool to the machining position of the clearance counterbored surface of the connecting rod and machine the clearance counterbored surface of the connecting rod; according to the machining parameters of the clearance chamfer of the connecting rod, driving the tool shank by the machine tool spindle to move the chamfering tool to the machining position of the clearance chamfer of the connecting rod and machine the clearance chamfer of the connecting rod; and driving the tool shank by the machine tool spindle to reset.

[0014] Even further, the machining parameters of the clearance chamfer of the connecting rod include the spindle speed and the feed rate. The spindle speed is 3000 r / min, and the feed rate is 450 mm / min.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. In terms of processing efficiency, the present invention integrates a countersinking tool and a chamfering tool on the same tool holder. Driven by the machine tool spindle, the two tools can reach the corresponding processing positions successively, realizing one-time processing of clearance countersinking and clearance chamfering, avoiding the cumbersome steps of frequent tool changing and axis movement in the prior art, greatly shortening the processing time, significantly improving the process rhythm, especially suitable for automated production lines, and effectively improving the overall output efficiency of the line.

[0017] 2. In terms of tool performance, the chamfering tool adopts a structure with multiple multi-edge carbide inserts fixed at circumferential intervals. The surface of the insert is coated with a nitride coating with a thickness of not less than 3.18 mm. At the same time, it adopts a design with a small back angle, clamp plate locking, and multi-sided machining. Compared with traditional single-edge cutting inserts, the strength is greatly improved; the countersinking tool is made of hard alloy steel, and the tool holder is made of high-speed steel. The overall tool material is excellent, combined with a reasonable structural design, significantly extending the tool life, reducing non-fault losses during equipment downtime, and reducing the safety risks of personnel and equipment.

[0018] 3. At the cost control level, the present invention reduces the number of tools, eliminates the need to configure multiple powerful self-locking tool holders, and the improvement of tool life reduces the tool replacement frequency. At the same time, combined with the appropriate processing parameters simulated by simulation software, it effectively reduces the cutting force and reduces insert wear, further reducing the processing cost; in addition, the multi-sided machining characteristics of the insert enable the insert to be reused multiple times, achieving cost optimization from multiple dimensions and improving the production economic benefits. Description of the Drawings

[0019] Figure 1 It is the front view of the processing area of the clearance countersinking and chamfering of the connecting rod of the engine block in the present invention;

[0020] Figure 2 It is the structural diagram of the clearance countersinking of the connecting rod in the present invention;

[0021] Figure 3 It is the structural diagram of the clearance chamfering of the connecting rod in the present invention;

[0022] Figure 4 It is the structural schematic diagram of the processing tool for the clearance chamfering and countersinking of the connecting rod of the engine block in the present invention;

[0023] Among them, 1 - tool holder, 2 - countersinking tool, 3 - chamfering tool (3.1 - chamfering insert), 4 - engine block, 5 - clearance countersinking of the connecting rod, 6 - clearance chamfering of the connecting rod, 7 - clamp plate, 8 - compression screw, 9 - countersinking cutting edge, 10 - chamfering cutting edge. Detailed Embodiment

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. are based on the orientation 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 thus should not be construed as a limitation to the present invention.

[0025] As Figure 1 shown in FIG. - 3, in the power transmission system of the engine, the connecting rod is a key component, and the smoothness of its movement path is directly related to the operating reliability of the engine. To avoid interference wear between the connecting rod and the side wall of the cylinder bore of the engine block (as Figure 1 shown), which may cause the engine to malfunction, the existing engine structure usually needs to machine a counterbore surface 5 for the connecting rod clearance (as Figure 2 shown) and a semi-circular chamfer 6 for the connecting rod clearance (as Figure 3 shown) on the side of the cylinder bore of the engine block to ensure the safe and stable movement of the connecting rod.

[0026] To machine the counterbore surface 5 for the connecting rod clearance and the chamfer 6 for the connecting rod clearance, the present invention designs a machining tool for the chamfered counterbore surface of the engine block connecting rod, and designs a machining method for machining the counterbore surface 5 for the connecting rod clearance and the chamfer 6 for the connecting rod clearance based on this machining tool.

[0027] As Figure 4 shown, in some embodiments, the machining tool for the chamfered counterbore surface of the engine block connecting rod includes a tool shank 1 made of high-speed steel. A counterbore machining tool 2 for machining the counterbore surface 5 for the connecting rod clearance of the engine block 4 and a chamfer machining tool 3 for machining the chamfer 6 for the connecting rod clearance of the engine block 4 are coaxially fixed on the tool shank 1. The tool shank 1 can be installed on the machine tool spindle, and by driving the tool shank 1 through the machine tool spindle, the counterbore machining tool 2 and the chamfer machining tool 3 can respectively reach the machining positions of the counterbore surface 5 for the connecting rod clearance and the chamfer 6 for the connecting rod clearance to machine the counterbore surface 5 for the connecting rod clearance and the chamfer 6 for the connecting rod clearance.

[0028] Embodiment 1

[0029] Provide a specific embodiment of installing the counterbore machining tool 2 on the tool shank 1:

[0030] One end of the tool shank 1 away from its installation with the machine tool spindle ( Figure 4In the middle of the left side of the middle tool shank 1, a tool mounting hole is axially provided. The countersinking tool 2 is an end mill with a pressing inclined surface ground on its shank part, made of hard alloy steel. Its shank part is coaxially inserted into the tool mounting hole, and the shank inclined surface of the end mill is pressed and mounted in the tool shank 1 by two pressing screws 8.

[0031] Embodiment Two

[0032] Provide a specific embodiment of installing a chamfering tool 3 on the tool shank 1:

[0033] The chamfering tool 3 includes a plurality of chamfering inserts 3.1 that are circumferentially spaced and fixed along the end of the tool shank 1 away from the end where it is installed on the machine tool spindle ( Figure 4 the left side of the middle tool shank 1). The chamfering inserts 3.1 are detachably fixed to the tool shank 1 by screws; and, a pressing plate 7 is also detachably fixed to the end of the tool shank 1 away from the end where it is installed on the machine tool spindle by screws. The pressing plate 7 presses the side of the chamfering insert 3.1 away from the countersinking tool 2 against the tool shank 1. The plurality of chamfering inserts 3.1 are arranged around the countersinking tool 2 (end mill). The chamfering inserts 3.1 are multi-edge, hard alloy inserts, and their surfaces are coated with a nitride coating with a thickness of not less than 3.18 mm. There is an axial distance and a radial distance between the cutting edges of the countersinking tool 2 and the cutting edges of the chamfering tool 3.

[0034] Embodiment Three

[0035] Based on the above machining tool for the clearance chamfering and countersinking of the engine cylinder block connecting rod, provide a machining method:

[0036] Step 1: Install the tool shank 1 on the machine tool spindle.

[0037] Step 2: According to the machining parameters of the connecting rod clearance countersinking, drive the tool shank 1 by the machine tool spindle to move the countersinking tool 2 to the machining position of the connecting rod clearance countersinking surface 5, and machine the connecting rod clearance countersinking surface 5.

[0038] Step 3: According to the machining parameters of the connecting rod clearance chamfering, drive the tool shank 1 by the machine tool spindle to move the chamfering tool 3 to the machining position of the connecting rod clearance chamfer 6, and machine the connecting rod clearance chamfer 6; the machine tool spindle drives the tool shank 1 to return to the original position.

[0039] Embodiment Four

[0040] Taking the machining of the connecting rod clearance countersinking surface 5 and the connecting rod clearance chamfer 6 of a certain 1.5L naturally aspirated engine cylinder block (engine cylinder block 4) as an example for illustration:

[0041] The diameter of the connecting rod clearance countersinking surface 5 is φ19mm (0 + 0.3), the connecting rod clearance chamfer 6 is a semi-circular arc type, and the arc diameter is φ40mm (0 + 0.3). The positional tolerance requirements for the clearance chamfer and surface are ±0.15.

[0042] In this embodiment, a vertical milling cutter with a diameter of (φ19.15) mm ± 0.05 is used as the countersinking tool 2 to machine the clearance countersink surface 5 of the connecting rod. A hole with a diameter of φ20H7 is drilled in the center of a non-standard tool holder (tool holder 1) with a diameter of (φ40.15) mm ± 0.05. The vertical milling cutter with a diameter of (φ19.15) mm ± 0.05 and a shank diameter of φ20 is inserted into the φ20H7 hole in the center of the non-standard tool holder with a diameter of (φ40.15) mm ± 0.05. The shank inclined surface of the vertical milling cutter is clamped by two M12 clamping screws 8 to form a combined structure between the vertical milling cutter and the tool holder 1.

[0043] Three chamfering blades 3.1 are evenly installed circumferentially on the tool holder 1. The chamfering blade 3.1 is a non-standard blade with an inscribed circle diameter of φ7 mm ± 0.025 and a thickness of 3.18 mm ± 0.013. The rake angle of the blade is 2° and the clearance angle is 7°.

[0044] The chamfering tool 3 and the countersinking tool 2 are combined to form a combined tool.

[0045] In this embodiment, the end face of the vertical milling cutter is 246 mm (±1 mm) away from the reference surface of the tool holder. The vertical milling cutter machines the clearance countersink surface 5 of the connecting rod according to the machining parameters of the clearance countersink surface of the connecting rod (the same as the prior art and will not be elaborated here). After the machining of the clearance countersink surface 5 of the connecting rod is completed, the chamfering tool 3 machines the clearance chamfer 6 of the connecting rod according to the machining parameters of the clearance chamfer of the connecting rod (the same as the prior art and will not be elaborated here) by moving each axis of the machine tool. The center of the chamfering blade 3.1 is 200.5 mm (±1 mm) away from the reference surface of the tool holder.

[0046] The chamfering blade 3.1 adopts a replaceable multi-edge machinable blade. The blade is made of cemented carbide + ALNTI coating and is installed by a pressing plate locking method. The machining parameters are S3000F450, which reduces the instantaneous impact force during intermittent cutting during machining, reduces the chipping and wear of the blade, and improves the service life of the blade. The vertical milling cutter is made of solid cemented carbide. The tool holder 1 is made of high-speed steel.

[0047] In summary, the present invention provides a machining tool and method that do not require frequent tool changes, can complete machining in one go, and have high tool blade strength. The machining tool consists of a tool shank 1 made of high-speed steel, a countersinking tool 2, and a chamfering tool 3. The countersinking tool 2 is a carbide end mill and is installed in the tool mounting hole in the middle of the tool shank 1 through a clamping screw 8. The chamfering tool 3 is composed of multiple multi-edge carbide inserts arranged at circumferential intervals. The surface of the inserts is coated with a nitride coating and is detachably fixed to the end of the tool shank 1 through screws and a pressing plate 7, and there are axial and radial distances from the cutting edge of the countersinking tool 2, so that the two can reach different machining positions successively. First, install the tool shank 1 on the machine tool spindle, and then drive the countersinking tool 2 by the machine tool spindle to complete the machining of the connecting rod clearance countersinking 5 according to the connecting rod clearance countersinking machining parameters; then move each axis of the machine tool and make the chamfering tool 3 complete the machining of the connecting rod clearance chamfer 6 according to the connecting rod clearance chamfering machining parameters, and finally drive the tool shank 1 by the machine tool spindle to reset. Taking the machining of a 1.5L naturally aspirated engine cylinder block as an example, the tool specifications, installation methods, and specific machining parameters are elaborated in detail. By using a combination of end mills with specific dimensions and non-standard tool shanks, reasonably arranging the chamfering inserts 3.1, and optimizing the machining parameters (spindle speed 3000 r / min, feed rate 450 mm / min), the cutting force is reduced, the tool blade wear is reduced, and the tool blade service life is improved, verifying the effectiveness and superiority of the present invention in practical applications. Through innovative tool structure design and machining methods, the problems of the existing technology are effectively solved, and it has significant advantages such as high machining efficiency, long tool life, and low cost, and has good application prospects and promotion value. It should be noted that the present invention is not limited to the combination of the countersinking tool 2 and the chamfering tool 3, and machining countersinking or drilling with lower precision requirements on the same surface as the connecting rod clearance countersinking 5 or the connecting rod clearance chamfer 6 can be considered for this combination structure and machining method to improve the machining efficiency of the cylinder block oil pan joint surface and reduce the production cost.

[0048] Here, it should be noted that the description of the above technical solution is exemplary. This specification can be embodied in different forms and should not be construed as limited to the technical solutions set forth herein. On the contrary, providing these descriptions will make the disclosure of the present invention thorough and complete, and will fully convey the scope disclosed in this specification to those skilled in the art. In addition, the technical solution of the present invention is only defined by the scope of the claims. The shapes, sizes, ratios, angles, and numbers disclosed for various aspects of this specification and the claims are merely examples. Therefore, this specification and the claims are not limited to the details shown. In the following description, when the detailed description of related known functions or configurations is determined to unnecessarily obscure the key points of this specification and the claims, the detailed description will be omitted. When using "including", "having", and "comprising" described in this specification, there may also be another part or other parts, and the terms used can generally be singular but can also represent plural forms.

[0049] Finally, it should be pointed out that the above embodiments are only relatively representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments and there can be many variations. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention should be considered to fall within the protection scope of the present invention.

Claims

1. A machining tool for countersinking chamfers for clearance of a connecting rod of an engine cylinder block, comprising a tool shank (1), characterized in that: A countersinking tool (2) for machining a clearance countersunk surface (5) of a connecting rod of an engine block (4) and a chamfering tool (3) for machining a clearance chamfer (6) of the connecting rod of the engine block (4) are coaxially fixed on the tool shank (1). There is an axial distance and a radial distance between the cutting edge of the countersinking tool (2) and the cutting edge of the chamfering tool (3). The tool shank (1) can be installed on a machine tool spindle, and the machine tool spindle drives the tool shank (1) to enable the countersinking tool (2) and the chamfering tool (3) to reach the machining positions of the clearance countersunk surface (5) of the connecting rod and the clearance chamfer (6) of the connecting rod respectively, and machine the clearance countersunk surface (5) of the connecting rod and the clearance chamfer (6) of the connecting rod.

2. The machining tool for the clearance chamfering and countersinking of the connecting rod of the engine cylinder block according to claim 1, wherein: A tool mounting hole is axially formed in the middle of the end of the tool shank (1) far from its installation end with the machine tool spindle, and the countersinking tool (2) is coaxially inserted and detachably fixed in the tool mounting hole.

3. The machining tool for the clearance chamfering and countersinking of the connecting rod of the engine cylinder block according to claim 1 or 2, characterized in that: The chamfering tool (3) includes a plurality of chamfering blades (3.1) fixedly spaced along the circumference of the end of the tool shank (1) far from its installation end with the machine tool spindle.

4. The machining tool for the chamfering and countersinking of the clearance between the engine cylinder block and the connecting rod, as claimed in claim 3, wherein: The chamfering blade (3.1) is detachably fixed on the tool shank (1).

5. The machining tool for the clearance chamfering and counterboring of the connecting rod clearance in the engine block according to claim 4, characterized in that: A pressing plate (7) for pressing the side of the chamfering blade (3.1) far from the countersinking tool (2) against the tool shank (1) is also detachably fixed on the end of the tool shank (1) far from its installation end with the machine tool spindle.

6. The machining tool for the clearance chamfering and countersinking of the connecting rod of the engine cylinder block according to claim 3, characterized in that: The chamfering blade (3.1) is a multi-edge cemented carbide blade, and its surface is coated with a nitride coating with a thickness of not less than 3.18 mm.

7. The machining tool for the clearance chamfer counterboring surface of the engine cylinder block connecting rod according to claim 4 or 5, characterized in that: The chamfering blade (3.1) is a multi-edge cemented carbide blade, and its surface is coated with a nitride coating with a thickness of not less than 3.18 mm.

8. The machining tool for the counterbore chamfer clearance of the engine block connecting rod according to claim 1 or 2, characterized in that: The countersinking tool (2) is made of hard alloy steel, and the tool shank (1) is made of high-speed steel.

9. A machining method for a machining tool of a clearance chamfer counterboring surface of an engine block connecting rod according to any one of the above-mentioned claims 1-7, characterized in that: It includes installing the tool shank (1) on the machine tool spindle; According to the machining parameters of the clearance countersunk surface of the connecting rod, the machine tool spindle drives the tool shank (1) to move the countersinking tool (2) to the machining position of the clearance countersunk surface (5) of the connecting rod and machine the clearance countersunk surface (5) of the connecting rod. According to the machining parameters of the clearance chamfer of the connecting rod, the machine tool spindle drives the tool shank (1) to move the chamfering tool (3) to the machining position of the clearance chamfer (6) of the connecting rod and machine the clearance chamfer (6) of the connecting rod; the machine tool spindle drives the tool shank (1) to reset.

10. The machining method of the machining tool for the clearance chamfering and countersinking of the engine block connecting rod as described in claim 9, characterized in that: The machining parameters of the clearance chamfer of the connecting rod include the spindle speed and the feed rate. The spindle speed is 3000 r / min, and the feed rate is 450 mm / min.

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