Integrated machining method and clamp for connecting rod positioning pin hole and bolt hole

Abstract

The invention provides an integrated machining method and clamp for a connecting rod positioning pin hole and a bolt hole, and belongs to the technical field of machining. According to the method, the functions of 360-degree rotation and automatic tool changing of a horizontal machining center workbench are utilized, a set of special integrated clamp is matched, and after the connecting rod is clamped at a time, machining of high-precision positioning pin holes and a plurality of bolt holes in a rod body of the connecting rod is sequentially completed. The clamp comprises a clamp base body, a positioning pin, a stop pin, a pressing plate, a positioning groove, a first alignment hole and a second alignment hole. During machining, a working table is rotated, a coordinate system is established with the two alignment holes as references, different machining parameters are called, and a machine tool automatically changes a tool to complete machining of the corresponding holes. Multiple procedures are integrated, the problems that traditional sequential machining is low in efficiency, precision is not prone to being guaranteed, and multiple clamps are needed are solved, and the machining method has the advantages of being high in machining precision, high in efficiency, low in cost and easy and convenient to operate.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, specifically relating to an integrated machining method and fixture for connecting rod positioning pin holes and bolt holes, and more particularly to a method and fixture for integrated machining of connecting rod body positioning pin holes and bolt holes on a horizontal machining center. Background Technology

[0002] The connecting rod is a key component of the crankshaft-connecting rod mechanism in a diesel engine, its function being to convert the reciprocating motion of the piston into the rotational motion of the crankshaft. In some new diesel engine designs, such as... Figure 4 As shown, a locating pin hole 11 is designed in the radial direction of the connecting rod big end hole to replace the traditional locking groove function. This locating pin hole needs to mate with the convex lip on the connecting rod bearing to achieve precise circumferential positioning of the big end bearing.

[0003] The challenges in machining this type of connecting rod lie in two aspects: First, the centerline of the locating pin hole 11 on the rod body forms a non-perpendicular angle (e.g., 8°) with the mating surface (Hafur surface) of the connecting rod, resulting in a complex spatial position. Second, the dimensional accuracy of the locating pin hole requires high precision, typically reaching IT7 grade. If traditional drilling machines are used, a dedicated inclined hole drilling jig must be designed and manufactured. During operation, frequent manual changes of drill bits and reamers of different diameters are necessary, along with corresponding changes to the drill bushing. This process is cumbersome, inefficient, and the machining accuracy is highly susceptible to human error, making it difficult to maintain consistent precision. Furthermore, the dedicated drilling jig has a single function, only used for machining pin holes. Machining bolt holes 10 requires a separate fixture, leading to high fixture design and manufacturing costs, complex fixture management on the production line, and low equipment utilization.

[0004] Therefore, there is an urgent need for a new processing method and device that can improve processing accuracy and efficiency while reducing costs and operational intensity. Summary of the Invention

[0005] The technical problem solved by this invention: The purpose of this invention is to overcome the shortcomings of the prior art and provide an integrated machining method and fixture for connecting rod positioning pin holes and bolt holes. This method aims to give full play to the advantages of fixtures and equipment, and complete the machining of multiple high-precision features in one clamping, thereby reducing the number of special fixtures, improving machining efficiency and quality, and reducing the labor intensity of operators and production costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An integrated machining method for connecting rod locating pin holes and bolt holes, using a horizontal machining center and a set of integrated fixtures, completes the machining of locating pin holes and bolt holes on the connecting rod body under the same clamping state, including the following steps: S1: Provides a horizontal machining center with a 360° rotating worktable and an automatic tool changer. S2: The integrated fixture is fixedly installed on the worktable through the positioning groove at its bottom; S3: Place the connecting rod blank on the integrated fixture, use the positioning pins and stop pins on the fixture to accurately position the connecting rod, and use the first pressure plate and the second pressure plate to press and fix the connecting rod. S4: Execute the positioning pin hole machining program: Control the table to rotate so that the center line of the first alignment hole on the fixture is parallel to the machine tool spindle. Using the coordinate position of the first alignment hole as the machining zero point, call the preset positioning pin hole coordinate parameters. The machine tool uses the automatic tool change function to change the special drill bit and special reamer in sequence. The spindle drives the tool to machine the positioning pin hole that meets the drawing requirements. S5: Execute the bolt hole machining program: While the connecting rod is in the clamping state of step S3, control the worktable to rotate again so that the center line of the second alignment hole on the fixture is parallel to the machine tool spindle. Using the coordinate position of the second alignment hole as the machining zero point, call the preset coordinate parameters of each bolt hole. The machine tool changes the corresponding drill bit, reamer or tapping tool through the automatic tool change function to complete the machining of all bolt holes.

[0007] Furthermore, the centerline of the positioning pin hole forms a set angle with the Huff surface of the connecting rod. In step S4, the centerline of the positioning pin hole is made parallel to the axis of the machine tool spindle by rotating the worktable.

[0008] Furthermore, the shanks of the special drill bit and special reamer used in step S4 are both lengthened and reinforced to adapt to the connecting rod body structure and ensure the rigidity and stability of the tool during the machining process.

[0009] An integrated fixture for implementing the integrated machining method includes a fixture base; Positioning pins and stop pins are disposed on the fixture base for cooperating with the connecting rod to achieve positioning. A first pressure plate and a second pressure plate are disposed on the fixture base for pressing the connecting rod; A machining window is provided on one side of the fixture base for the cutting tool to extend into during machining to process features on the connecting rod. A positioning slot is provided at the bottom of the fixture base for installation in conjunction with the worktable of the horizontal machining center; The first and second alignment holes set on the fixture base serve as coordinate zero-point references when machining the positioning pin holes and bolt holes, respectively.

[0010] Furthermore, the fixture base has an avoidance structure B surface in the area corresponding to the positioning pin hole of the machining connecting rod body, which is used to avoid interference between the fixture and the machine tool spindle or cutting tool during the machining process.

[0011] Furthermore, the positions of the positioning pin and the stop pin are set according to the external contour of the connecting rod body and the positional relationship of the hole to be machined, so as to achieve a unique and definite position of the connecting rod in the fixture.

[0012] Furthermore, the distribution of the clamping points of the first and second pressure plates ensures that the connecting rod does not shift or vibrate throughout the entire processing.

[0013] Advantages of this invention compared to existing technologies: 1. This solution offers high machining accuracy and stable quality: Utilizing the high positioning accuracy and automated machining capabilities of CNC machine tools, human error is avoided. Specialized fixtures ensure consistent workpiece positioning, resulting in stable pin hole angles and diameters that meet drawing requirements. 2. This solution significantly improves production efficiency: it enables the completion of machining operations at two stations in a single setup, reducing workpiece loading / unloading, turnaround time, and tool setting time. The automatic tool changer replaces manual tool change, shortening auxiliary time. 3. This solution significantly reduces costs: replacing multiple sets of dedicated drilling jigs with a single integrated fixture reduces fixture design, manufacturing, and management costs; at the same time, it improves machine tool utilization. 4. This solution reduces the difficulty and intensity of operation: operators only need to complete loading and unloading and start the program. Complex angle adjustments, tool changes and processing are all completed automatically by the machine tool, resulting in low labor intensity and reduced skill requirements; 5. This solution has strong versatility and scalability: This method (rotating indexing of the worktable and machining multiple surfaces in one clamping) can be widely applied to the machining of parts with complex spatial angle hole systems, providing an effective solution for similar technical problems. Attached Figure Description

[0014] Figure 1 This is a top view of the integrated fixture in this invention; Figure 2 For the present invention Figure 1 AA section view in the middle; Figure 3 This is a schematic diagram of the tool structure in this invention; Figure 4 This is a schematic diagram of the connecting rod manufactured according to the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0017] Please see Figure 1-4 The embodiments of the present invention are described in detail below.

[0018] Firstly, an integrated machining method for connecting rod positioning pin holes and bolt holes is provided. Its core lies in utilizing the 360° rotation and automatic tool changing function of the horizontal machining center's worktable, along with a set of multi-functional integrated fixtures, to realize the sequential machining of positioning pin holes and bolt holes after the connecting rod is clamped once.

[0019] The method specifically includes the following steps: 1. Equipment and Clamping: The integrated fixture is fixed to the worktable of the horizontal machining center via the positioning groove 7 on its bottom. The connecting rod blank is placed in the fixture, and precise positioning is achieved using the positioning pin 1 and the stop pin 2 on the fixture. The connecting rod is then pressed and fixed using the first pressure plate 3 and the second pressure plate 4.

[0020] 2. Machining of locating pin hole 11: The CNC system controls the rotation of the worktable to align the centerline of the preset first alignment hole 9 on the fixture with the machine tool spindle. Using this alignment hole as the coordinate zero point, the preset coordinate parameters of the locating pin hole are called. During machining, the machine tool automatically changes tools, sequentially using a specially made extended drill bit and an extended reamer to complete drilling and reaming, machining the locating pin hole that meets the drawing requirements, ensuring the dimensional accuracy and angle requirements of the pin hole.

[0021] 3. Machining of bolt holes 10: Without disassembling the connecting rod, the CNC system controls the worktable to rotate again, so that the center line of the preset second alignment hole 8 on the fixture is parallel to the machine tool spindle. Using this as the new zero point, the preset coordinate parameters of each bolt hole are called for machining. The machine tool completes the drilling, reaming, tapping and other processes of all bolt holes through automatic tool changing.

[0022] In the above steps, the center line of the locating pin hole forms a set angle with the connecting rod's Hover surface. By rotating the worktable, the center line of the locating pin hole is made parallel to the machine tool spindle axis.

[0023] The shanks of the specialized drill bits and reamers used have been lengthened and reinforced to adapt to the connecting rod structure and ensure the rigidity and stability of the tools during machining.

[0024] Secondly, an integrated fixture for implementing the above method is provided, such as... Figure 1 , Figure 2 , Figure 3 As shown, it includes the fixture base 6; Positioning pins 1 and 2 are mounted on the fixture base 6 to engage with the connecting rod for positioning. The positions of positioning pins 1 and 2 are determined based on the external contour of the connecting rod and the positional relationship of the hole to be machined, thus ensuring a unique and definite position of the connecting rod within the fixture. Together, they constitute the main positioning system for the connecting rod, restricting multiple degrees of freedom of the connecting rod.

[0025] A first pressure plate 3 and a second pressure plate 4 are mounted on the fixture base 6 to clamp the connecting rod. The first and second pressure plates provide clamping force from different directions to ensure that the connecting rod does not shift or vibrate during the entire processing, thus ensuring stability during processing.

[0026] A machining window is provided on one side of the fixture base 6 for the cutting tool 5 to extend into during machining to process features on the connecting rod, providing an entry path for the cutting tool.

[0027] The positioning groove 7, located at the bottom of the fixture base 6, is used to cooperate with the horizontal machining center worktable for installation. It is used to cooperate with the T-slot or positioning key on the machine tool worktable to achieve fast and accurate positioning of the fixture on the machine tool.

[0028] The first alignment hole 9 and the second alignment hole 8 set on the fixture base 6 serve as the coordinate zero point reference when machining the positioning pin hole and the bolt hole, respectively, ensuring the uniformity and accuracy of the machining coordinate system after two rotations.

[0029] The fixture base 6 has a clearance structure B surface in the area corresponding to the positioning pin hole of the machining connecting rod body. This is to provide sufficient movement space for the extended tool or spindle head when machining pin holes with an inclined angle, and to prevent collision interference.

[0030] The method of this invention has been applied and verified in actual production. The processed connecting rod products fully meet the requirements of the design drawings, proving the feasibility and superiority of the method.

[0031] It will be apparent to those skilled in the art that the present 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 its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0032] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for integrating the machining of connecting rod positioning pin holes and bolt holes, characterized in that: Using a horizontal machining center and an integrated fixture, the locating pin holes and bolt holes on the connecting rod body are machined under the same clamping condition, including the following steps: S1: Provides a horizontal machining center with a 360° rotating worktable and an automatic tool changer; S2: The integrated fixture is fixedly installed on the worktable through the positioning groove (7) at its bottom; S3: Place the connecting rod blank on the integrated fixture, use the positioning pin (1) and the stop pin (2) on the fixture to accurately position the connecting rod, and use the first pressure plate (3) and the second pressure plate (4) to press and fix the connecting rod. S4: Machining of positioning pin holes: Control the rotation of the worktable so that the center line of the first alignment hole (9) on the fixture is parallel to the machine tool spindle. Using the coordinate position of the first alignment hole (9) as the machining zero point, call the preset positioning pin hole coordinate parameters. The machine tool changes the special drill bit and reamer in sequence through the automatic tool change function. The spindle drives the tool (5) to machine the positioning pin hole that meets the requirements of the drawing. S5: Bolt hole machining: While the connecting rod is in the clamping state of step S3, control the worktable to rotate again so that the center line of the second alignment hole (8) on the fixture is parallel to the machine tool spindle. Using the coordinate position of the second alignment hole (8) as the machining zero point, call the preset coordinate parameters of each bolt hole. The machine tool changes the corresponding drill bit, reamer or tapping tool through the automatic tool change function to complete the machining of all bolt holes.

2. The integrated processing method according to claim 1, characterized in that: The centerline of the positioning pin hole forms a set angle with the Huff surface of the connecting rod. In step S4, the centerline of the positioning pin hole is made parallel to the axis of the machine tool spindle by rotating the worktable.

3. The integrated processing method according to claim 1, characterized in that: The shanks of the special drill bit and reamer used in step S4 are lengthened and reinforced to accommodate the connecting rod structure and ensure tool rigidity and stability during machining.

4. An integrated fixture for implementing the integrated machining method according to any one of claims 1-3, characterized in that: Including the fixture base (6); Positioning pin (1) and stop pin (2) are provided on the fixture base (6) for cooperating with the connecting rod to achieve positioning. A first pressure plate (3) and a second pressure plate (4) are disposed on the clamp base (6) for pressing the connecting rod. A machining window is provided on one side of the fixture base (6) for the cutting tool (5) to extend into during machining to machine the features on the connecting rod; A positioning groove (7) is provided at the bottom of the fixture base (6) for installation in conjunction with the horizontal machining center worktable. The first alignment hole (9) and the second alignment hole (8) set on the fixture base (6) serve as the coordinate zero point reference when machining the positioning pin hole and the bolt hole, respectively.

5. The integrated fixture according to claim 4, characterized in that: The fixture base (6) has an avoidance structure B surface in the area corresponding to the positioning pin hole of the machining connecting rod body, which is used to avoid interference between the fixture and the machine tool spindle or tool during the machining process.

6. The integrated fixture according to claim 4, characterized in that: The positions of the positioning pin (1) and the stop pin (2) are set according to the external contour of the connecting rod body and the positional relationship of the hole to be processed, so as to achieve a unique and definite position of the connecting rod in the fixture.

7. The integrated fixture according to claim 4, characterized in that: The distribution of the clamping points of the first pressure plate (3) and the second pressure plate (4) can ensure that the connecting rod does not shift or vibrate during the entire processing.

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