A camshaft hole positioning type engine case alignment tool

Abstract

The application provides a camshaft hole positioning type engine box alignment tool and relates to the technical field of machining.The engine box alignment tool comprises a positioning plate, a supporting piece and an expandable mandrel assembly, the supporting piece is fixedly installed on the positioning plate, the expandable mandrel assembly is arranged above the supporting piece, the expandable mandrel assembly comprises a front end expansion sleeve seat, a rear end taper shaft seat and a mandrel body, one end of the mandrel body is connected with the front end expansion sleeve seat, the other end of the mandrel body is connected with the rear end taper shaft seat, the front end expansion sleeve seat is internally provided with a sliding column, a front end adjusting screw and a steel ball, the front end adjusting screw is in threaded connection with the front end expansion sleeve seat, and the steel ball is in abutment between the front end adjusting screw and the sliding column.The positioning mode of taking the camshaft hole as a key hole reference and taking the non-machining surface of the box as a plane reference is adopted, so that the tool machining reference and the box design reference are kept consistent, the reference non-coincidence error is avoided from the root, and the size of the box after machining meets the design requirements of the drawings.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, and more specifically, it relates to a camshaft hole positioning engine housing alignment fixture. Background Technology

[0002] The engine housing is the core basic component of the engine. Its structure is complex and the cavity wall thickness is uneven. In the machining process, scribing is an indispensable process for the housing.

[0003] The scribing process determines the machining allowance for the enclosure during processing, providing clear dimensional boundaries. For subsequent machining, the scribing lines allow for workpiece alignment and accurate positioning. It also verifies whether the quality of the raw material meets processing requirements. Currently, in the industry, scribing is commonly used to verify the quality of the raw material and as a reference for subsequent enclosure machining.

[0004] While this traditional process has the advantage of clearly identifying the machining allowance of the blank, it is only suitable for small-batch production. In the mass production of engine housings, this process has extremely low cost-effectiveness and suffers from the prominent problem of low efficiency in rough datum alignment, which cannot meet the efficiency requirements of mass production. At the same time, the manual scribing method is also prone to introducing human error, affecting the stability of the housing machining quality. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a camshaft hole positioning engine housing alignment fixture. This addresses the issue that traditional processes are only suitable for small-batch production. In mass production of engine housings, these processes are extremely inefficient, exhibiting low efficiency in coarse datum alignment, and cannot meet the efficiency requirements of large-scale production. Furthermore, manual scribing can easily introduce human error, affecting the stability of the housing's machining quality.

[0006] A camshaft bore positioning engine housing alignment fixture includes a positioning plate, a support component, and an expandable mandrel assembly;

[0007] The support is fixedly installed on the positioning plate, and the expandable mandrel assembly is mounted on top of the support, completely replacing the traditional manual scribing and alignment process. The rough datum positioning is completed in one clamping, which greatly improves the efficiency of batch box processing.

[0008] Preferably, the expandable mandrel assembly includes a front expansion sleeve seat, a rear tapered shaft seat, and a mandrel body. One end of the mandrel body is connected to the front expansion sleeve seat, and the other end of the mandrel body is connected to the rear tapered shaft seat. The split mandrel structure facilitates installation and disassembly, adapts to camshaft holes of different engine housing specifications, and has greater versatility.

[0009] Preferably, the front expansion sleeve seat is provided with a sliding column, a front adjusting screw and a steel ball. The front adjusting screw is threaded to the front expansion sleeve seat, the steel ball abuts between the front adjusting screw and the sliding column, and the sliding column is slidably connected to the front expansion sleeve seat. The radial feed of the sliding column is achieved through the transmission of the screw and the steel ball, and the tightening force is uniform and controllable, effectively improving the positioning accuracy.

[0010] Preferably, the expandable mandrel assembly also includes a rear locking nut, which is threaded to the end of the rear tapered shaft seat to lock the axial relative position of the mandrel and the housing, preventing movement during processing and ensuring processing stability.

[0011] Preferably, the expandable mandrel assembly also includes a locking ring, which is sleeved on the outer periphery of the front expansion sleeve seat to limit the maximum radial stroke of the slide column, prevent the slide column from dislodging from the expansion sleeve seat, and improve the safety and reliability of the tooling.

[0012] Preferably, the positioning plate is provided with a support component, which consists of three fixed supports and one floating support. This component adapts to the unevenness of the positioning surface of the box blank, achieves multi-point stable support, and avoids deformation during the clamping process.

[0013] Preferably, the floating support includes a support column, a locking screw, a spring, and an internal hexagon screw. The spring is sleeved on the outside of the support column, the locking screw is threaded to the housing of the floating support, and the internal hexagon screw is installed at the bottom of the support column. The spring automatically fits against the rough surface of the housing, and after locking, it maintains sufficient support rigidity, taking into account both adaptability and stability.

[0014] Preferably, the axis of the mandrel body coincides with the axis of the front expansion sleeve seat and the rear tapered shaft seat, ensuring the overall coaxiality of the mandrel and making the positioning reference completely coincide with the axis of the camshaft hole, thus eliminating reference deviation.

[0015] Preferably, there are three sliding pillars, which are evenly distributed around the front end expansion sleeve seat. The three pillars evenly expand and tighten the inner wall of the camshaft hole at three points, resulting in balanced force without off-center load, good self-centering effect, and stable positioning accuracy.

[0016] Preferably, the end of the slide column facing the steel ball is provided with a conical surface, which abuts against the outer surface of the steel ball, converting the axial force of the steel ball into the radial force of the slide column, resulting in smooth transmission and sensitive and reliable tightening action.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In this invention, the solution adopts a positioning method that uses the camshaft hole as the key hole reference and the non-machined surface of the housing as the plane reference, so that the tooling machining reference is consistent with the housing design reference, thereby avoiding the error of reference non-coincidence from the root and ensuring that the dimensions of the housing after machining meet the design requirements of the drawings.

[0019] In this invention, the traditional manual scribing and alignment process is completely replaced, saving all the operation and preparation time of the scribing process, solving the core problem of low efficiency of rough datum alignment in batch engine housing processing, and significantly shortening the processing cycle of a single housing.

[0020] In this invention, the radial expansion structure of the slide column of the expandable mandrel assembly enables automatic centering and positioning of the camshaft hole, avoiding human error caused by manual scribing. The positioning accuracy is stable and repeatable, ensuring that the positioning reference of each housing is consistent.

[0021] In this invention, a combination of three fixed supports and one floating support is used to adapt to the uneven wall thickness of the positioning surface of the box blank, so that the box blank surface and the support are fully in contact, there are no suspended points during the clamping process, and the box is effectively prevented from shaking or displacing during the processing.

[0022] In this invention, the entire alignment and clamping process can be completed in one operation, without the need to adjust the workpiece position or realign it midway, reducing clamping auxiliary time, reducing the labor intensity of operators, and further improving the processing efficiency of mass production.

[0023] In this invention, the tooling positioning accuracy is not affected by the operator's skill level. All boxes use the same positioning reference and clamping method, ensuring stable and uniform processing quality of boxes produced in batches and significantly reducing the scrap rate caused by alignment deviation. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0025] Figure 2 This is a schematic cross-sectional view of the expandable mandrel assembly of the present invention;

[0026] Figure 3 This is a schematic diagram of the planar structure of the expandable mandrel assembly of the present invention;

[0027] Figure 4 This is a partial structural diagram of the expandable mandrel of the present invention;

[0028] Figure 5 This is a schematic diagram of the floating support structure of the present invention.

[0029] In the diagram, the correspondence between the component names and the attached drawing numbers is as follows: 1. Positioning plate; 2. Support component; 3. Expandable mandrel assembly; 4. Front expansion sleeve seat; 5. Rear tapered shaft seat; 6. Mandrel body; 7. Sliding column; 8. Front adjusting screw; 9. Steel ball; 10. Rear locking nut; 11. Locking ring; 12. Floating support; 13. Support column; 14. Locking screw; 15. Spring; 16. Socket head cap screw. Detailed Implementation

[0030] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0031] Please see Figures 1-5 This invention provides a camshaft hole positioning engine housing alignment fixture. The fixture includes a positioning plate 10, a support member 11, and an expandable mandrel assembly. The support member 11 is vertically fixed to the upper surface of the positioning plate 10 by bolts, forming a rigid bearing base that can stably bear the weight of the housing and the machining cutting force. The expandable mandrel assembly is horizontally mounted on the top of the support member 11, with its axis parallel to the upper surface of the positioning plate 10. It is used to insert into the camshaft hole of the housing to achieve center positioning. This fixture is designed with the camshaft hole as the key hole reference and the unmachined blank surface of the housing as the plane reference, so that the machining reference and the design reference are completely unified. It completely eliminates the traditional manual scribing process, and the rough reference alignment can be completed in one clamping. The alignment time of a single housing is greatly shortened, solving the core problem of low alignment efficiency in mass production.

[0032] The expandable mandrel assembly adopts a three-section coaxial split structure, consisting of a front expansion sleeve seat 1, a rear tapered shaft seat 2, and a mandrel body 3. The front end of the mandrel body 3 is press-fitted into the rear center hole of the front expansion sleeve seat 1, and the rear end is press-fitted into the front center hole of the rear tapered shaft seat 2. After assembly, it forms an integral rigid mandrel. This split structure makes it easy to insert the mandrel into a long camshaft hole, avoiding the difficulty of insertion caused by an excessively long overall mandrel. At the same time, when a component is damaged, it can be replaced separately without scrapping the entire mandrel assembly, which improves the versatility and maintenance convenience of the tooling and reduces long-term use costs.

[0033] The front expansion sleeve 1 has a coaxial axial threaded hole, a steel ball receiving cavity, and a radial sliding hole inside. The front adjusting screw 6 forms a precision threaded connection with the axial threaded hole, which can achieve precise axial feed through rotation. The steel ball 7 is placed in the receiving cavity and abuts against the end face of the screw on one side, which can evenly transmit the axial force of the screw. The slide column 5 is slidably installed in the radial sliding hole and its inner end abuts against the steel ball 7, which can slide freely in the radial direction. This structure, through the combination of helical drive and spherical drive, smoothly converts the rotational motion of the screw into the radial tightening motion of the slide column. The magnitude of the tightening force can be precisely controlled by the number of screw rotations, avoiding insufficient tightening force leading to loose positioning or excessive tightening force damaging the blank hole.

[0034] The rear outer surface of the tapered shaft seat 2 is machined with an external thread section. The rear locking nut 4 forms a threaded engagement with the external thread section. The front face of the rear locking nut 4 is a flat annular pressing surface, which can tightly abut against the rear face of the housing when tightened. This structure can further lock the axial relative position of the mandrel and the housing after the mandrel is radially expanded and positioned, effectively resisting the axial cutting force generated during the machining process, preventing the mandrel from axially moving, ensuring the stability of the positioning reference during the machining process, avoiding machining dimensional deviations caused by mandrel movement, and improving the product qualification rate.

[0035] An annular groove is provided on the outer periphery of the front expansion sleeve seat 1, and the locking ring 8 is fixed in the annular groove. The inner ring of the locking ring 8 covers the outer end opening of the radial sliding hole, forming a physical limiting structure for the radial outward movement of the slide column 5. This structure can precisely limit the maximum radial stroke of the slide column, preventing the operator from excessively rotating the front adjusting screw 6 and causing the slide column to fall out of the expansion sleeve seat. At the same time, it can also prevent the slide column from excessively tightening and squeezing the inner wall of the camshaft hole, causing deformation or damage to the blank hole, thereby improving the safety and reliability of the tooling and extending the service life of the tooling.

[0036] The support 11 on the positioning plate 10 consists of three fixed supports and one floating support 12. The three fixed supports are distributed in an equilateral triangle on the upper surface of the positioning plate 10, forming a stable three-point reference support plane. The floating support 12 is installed inside the triangular area enclosed by the three fixed supports. This combined support layout perfectly adapts to the characteristics of uneven wall thickness and uneven surface of the engine box blank positioning surface. The three fixed supports ensure the accuracy of the reference plane, while the floating support can fill the concave parts of the blank surface, achieving multi-point full fit support, avoiding the internal stress generated by the box due to local suspension during the clamping process, and preventing the box from deforming after processing.

[0037] The floating support 12 includes a housing, a support column 13, a locking screw 14, a spring 15, and a hexagon socket screw 16. The spring 15 is sleeved on the outside of the support column 13, with its upper and lower ends abutting against the annular boss in the middle of the support column and the bottom surface of the housing, respectively, providing continuous upward elastic force. The locking screw 14 is threaded to the side wall of the housing, and its end abuts against the side wall of the support column to lock it in place. The hexagon socket screw 16 is installed at the bottom of the support column to limit the maximum upward stroke of the support column. This structure relies on the elastic force of the spring to make the support column automatically follow the undulations of the box blank surface, eliminating the need for manual adjustment of the support height. The operation is simple and quick. After the locking screw is locked, it provides sufficient support rigidity to withstand the cutting load during processing, taking into account both adaptability to the blank surface and support stability.

[0038] The main body 3 of the mandrel is a hollow cylindrical rod. Its axis is completely coincident with the axis of the front expansion sleeve seat 1 and the axis of the rear tapered shaft seat 2. After the three are assembled, they form an integral rigid mandrel with extremely high coaxiality. This structure ensures the overall rotational accuracy of the mandrel and makes the positioning reference of the mandrel completely coincide with the design reference of the camshaft hole. This eliminates the error of reference non-coincidence from the root and ensures the positional accuracy of each hole and plane relative to the camshaft hole in subsequent processing, providing a basic guarantee for the overall processing quality of the housing.

[0039] Three radial sliding holes are opened on the front expansion sleeve seat 1. The three sliding holes are evenly distributed around the circumference of the front expansion sleeve seat 1. Correspondingly, there are three sliding pins 5, which are slidably installed in the three radial sliding holes. This three-point circumferentially evenly distributed structure can make the force on the inner wall of the camshaft hole evenly distributed when the sliding pin is tightened. The force is balanced and there is no off-center load. It will not cause the mandrel to become eccentric. The self-centering effect is excellent. At the same time, the positioning accuracy of each box is not affected by the skill level of the operator, ensuring the consistency of the positioning reference of all boxes in mass production, and making the product processing quality stable and uniform.

[0040] Each sliding column 5 has a tapered bevel machined on its inner end face facing the steel ball 7. The angle of the tapered bevel matches the spherical curvature of the steel ball 7. The outer surface of the steel ball 7 is in close contact with the tapered bevel. This tapered surface mating structure can efficiently and evenly convert the axial force of the steel ball into the radial force of the sliding column. It has high transmission efficiency and no jamming. The tightening action is sensitive and reliable. A slight rotation of the front adjusting screw 6 can generate sufficient tightening force, which is labor-saving. At the same time, it avoids problems such as slippage and uneven force transmission when the steel ball contacts the plane of the sliding column, and improves the stability of the tightening and positioning.

[0041] Working principle:

[0042] First, insert the front end of the expandable mandrel assembly into the camshaft hole on the front face of the engine housing, and then insert the rear end tapered shaft seat 2 of the other end of the mandrel assembly into the corresponding hole on the rear face of the housing, so that the mandrel body 3 passes through the entire camshaft hole, thus completing the initial coaxial installation of the mandrel and the housing.

[0043] The second step is to rotate the front adjusting screw 6 to feed it inward along the axial direction, pushing the steel ball 7 against its end to move forward. The steel ball 7 presses the inner end conical surface of the slide column 5, causing the slide column 5 to slide outward along the radial through hole of the front expansion sleeve seat 1 until the outer end face of the slide column 5 is tightly attached to the inner wall of the camshaft hole. At this time, the axis of the spindle body 3 is completely coincident with the axis of the camshaft hole, realizing rigid positioning based on the camshaft hole. The locking ring 8 is assembled on the outer circumference of the front expansion sleeve seat 1 to limit the radial travel of the slide column 5.

[0044] The third step is to align and tighten the rear tapered shaft seat 2 with the front expansion sleeve seat 1 at the front end of the spindle, and then tighten the rear locking nut 4 to lock the axial relative position between the spindle assembly and the housing, preventing the spindle from moving axially during the processing.

[0045] Fourth step: Place the assembled expandable mandrel assembly onto the positioning plate 10, so that the unmachined blank surface of the box contacts the support 11. The support 11 consists of three fixed supports and one floating support 12. The three fixed supports provide reference support. When the box is pressed down by its own weight, the spring 15 in the floating support 12 is compressed, and the support column 13 moves down until the blank surface of the box is completely in contact with the support column 13 of the three fixed supports and the floating support 12. At this time, tighten the locking screw 14 on the floating support 12 with a wrench to lock the position of the support column 13, thus completing the stable support with the unmachined surface as the plane reference.

[0046] Fifth step: After the housing is processed, first loosen the locking screw 14 of the floating support 12 to release the lock on the support column 13; remove the housing together with the expandable mandrel assembly from the positioning plate 10, rotate the front adjusting screw 6 in the opposite direction to release the compression on the steel ball 7 and the slide column 5, the slide column 5 retracts inward under the action of the radial spring, the tension between the expandable mandrel assembly and the camshaft hole disappears, and then pull out the rear tapered shaft seat 2 and the front expansion sleeve seat 1 in sequence to complete the separation of the tooling from the housing. The tooling can be reused for the processing of the next housing.

[0047] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A camshaft hole positioning engine housing alignment fixture, characterized in that: Includes a positioning plate (10), a support (11), and an expandable mandrel assembly; The support (11) is fixedly installed on the positioning plate (10), and the expandable mandrel assembly is mounted above the support (11).

2. The camshaft hole positioning engine housing alignment fixture as described in claim 1, characterized in that, The expandable mandrel assembly includes a front expansion sleeve seat (1), a rear tapered shaft seat (2) and a mandrel body (3). One end of the mandrel body (3) is connected to the front expansion sleeve seat (1), and the other end of the mandrel body (3) is connected to the rear tapered shaft seat (2).

3. The camshaft hole positioning engine housing alignment fixture as described in claim 2, characterized in that, The front expansion sleeve seat (1) is provided with a sliding column (5), a front adjusting screw (6) and a steel ball (7). The front adjusting screw (6) is threadedly connected to the front expansion sleeve seat (1), and the steel ball (7) abuts between the front adjusting screw (6) and the sliding column (5). The sliding column (5) is slidably connected to the front expansion sleeve seat (1).

4. The camshaft hole positioning engine housing alignment fixture as described in claim 3, characterized in that, The expandable mandrel assembly also includes a rear locking nut (4), which is threaded to the end of the rear tapered shaft seat (2).

5. The camshaft hole positioning engine housing alignment fixture as described in claim 4, characterized in that, The expandable mandrel assembly also includes a locking ring (8), which is fitted around the outer periphery of the front expansion sleeve seat (1).

6. The camshaft hole positioning engine housing alignment fixture as described in claim 5, characterized in that, The positioning plate (10) is provided with a support, which consists of three fixed supports and one floating support (12).

7. The camshaft hole positioning engine housing alignment fixture as described in claim 6, characterized in that, The floating support includes a support column (13), a locking screw (14), a spring (15), and an internal hex screw (16). The spring (15) is sleeved on the outside of the support column (13), the locking screw (14) is threaded to the housing of the floating support, and the internal hex screw (16) is installed at the bottom of the support column (13).

8. The camshaft hole positioning engine housing alignment fixture as described in claim 7, characterized in that, The axis of the spindle body (3) coincides with the axis of the front expansion sleeve seat (1) and the rear tapered shaft seat (2).

9. The camshaft hole positioning engine housing alignment fixture as described in claim 8, characterized in that, There are three sliding pins (5), and the three sliding pins (5) are evenly distributed along the circumference of the front end expansion sleeve seat (1).

10. The camshaft hole positioning engine housing alignment fixture as described in claim 9, characterized in that, The sliding column (5) has a conical surface at one end facing the steel ball (7), and the conical surface abuts against the outer surface of the steel ball (7).

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