Crankshaft heat treatment out-of-tolerance control device and method

Abstract

The invention provides a crankshaft heat treatment out-of-tolerance control device and a crankshaft heat treatment out-of-tolerance control method, relates to the field of constraint tools, and aims to solve the technical problem of insufficient subsequent machining allowance or direct scrapping caused by difficult-to-control deformation of a crankshaft in the length direction in the vertical hanging heat treatment process at present. The first restraining tool is provided with a restraining hole for the crank arm to stretch in, and is matched with a wedge block for use, so that the trend that the crank arm expands outwards under the action of gravity is limited, the distance between the crank arms is locked in the heat treatment process, and the crank arms are prevented from being lengthened due to self weight; the second constraint tool is provided with a constraint block extending between the crank arms, the constraint block is arranged on the inner sides of the crank arms, and the stress of inward collapse or closing of the crank arms is resisted in the cooling shrinkage process, so that the length of the crankshaft is prevented from being shortened; the first restraining tool and the second restraining tool are inserted into the restraining grooves through the wedge blocks at the wedge-shaped ends to abut against the end face of the crank arm, and the wedge-shaped matching structure solves the problem of tolerance matching between the tools and the roughly machined crankshaft.

Description

Technical Field

[0001] This invention relates to the field of constraint tooling, and more specifically to a crankshaft heat treatment deviation control device and method. Background Technology

[0002] During manufacturing, crankshafts undergo quenching and high-temperature tempering to achieve high strength, toughness, and fatigue strength. The crankshaft is vertically suspended for heating and cooling using a pit-type resistance furnace and a pit-type water tank. After tempering, the presence of internal thermal and structural stresses increases crankshaft runout and causes elongation or shortening deformation along its length. For crankshafts with significant length variations, this directly affects subsequent machining accuracy. Excessive elongation prevents grinding, while excessive shortening below the minimum required machining dimension leaves insufficient machining allowance, hindering finishing and potentially leading to scrap. While crankshafts with minor length variations can be reworked by adding straightening and stress-relief processes, this still increases production costs and extends the production cycle.

[0003] Especially when crankshafts are vertically suspended for quenching, the damper end is typically suspended. Due to the crankshaft's own weight and the thermal expansion and contraction during heat treatment, the first crankshaft near the top of the damper often bears the greatest tensile force, resulting in the largest elongation deformation. Conversely, during quenching and cooling, the first crankshaft near the bottom of the flywheel experiences the fastest shrinkage deformation due to its cooling characteristics. However, existing conventional production processes mostly rely on passive correction after deformation, leading to a prolonged process flow and impacting production efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a crankshaft heat treatment deviation control device and method, which is installed at the critical crankshaft crank before the tempering operation, and performs anti-stretching control and anti-shortening support by means of mechanical limiting, thereby solving the problem of dimensional deviation caused by the characteristics of heat treatment process.

[0005] The first objective of this invention is to provide a crankshaft heat treatment tolerance control device, which employs the following solution: include: The first constraint fixture has a constraint hole for the crank arm to be inserted into. The wall of the constraint hole has a first constraint groove that opens to communicate with the constraint hole. The opening of the first constraint groove faces the end face of the crank arm inserted into the constraint hole. The second constraint fixture is provided with a constraint block that extends between the crank arms. A second constraint groove is provided on the end of the constraint block along the crankshaft axis, and the opening of the second constraint groove faces the end face of the crank arm. The wedge has a wedge-shaped end for inserting into the first constraint groove and / or the second constraint groove to abut against the end face of the crank arm and constrain the crank arm spacing.

[0006] The first constraint fixture has two spaced constraint holes for different crank arms to insert into, and each constraint hole has a first constraint groove.

[0007] Furthermore, at least two first constraint grooves are provided on the same side of the crank arm end face inside the constraint hole, and at least two wedges located in the first constraint grooves abut against the same crank arm end face inside the constraint hole.

[0008] Furthermore, the constraint hole is provided with first constraint grooves on both sides of the crank arm that are inserted into it, and there is a gap between the first constraint groove and the crank arm end face to which it faces.

[0009] Furthermore, the first constraint fixture and the second constraint fixture are provided with an arc surface adapted to the journal on the journal side, and the first constraint fixture, the second constraint fixture and the wedge are made of heat-resistant steel.

[0010] Furthermore, at least two spaced second constraint grooves are respectively opened at both ends of the second constraint fixture, and wedges are respectively fitted therewith, with at least two wedges located at the same end abutting against the same crank arm end face.

[0011] Furthermore, the wedge-shaped end of the wedge abuts against the crank arm end face on one side, which is a contact plane parallel to its insertion direction. The wedge-shaped end abuts against the first constraint groove or the second constraint groove on one side, which is a propulsion plane inclined relative to the contact plane. The first constraint groove and the second constraint groove are provided with reaction planes that conform to the propulsion plane, so as to control the wedge to apply force to the crank arm end face in the direction perpendicular to the crank arm end face.

[0012] Furthermore, the end of the wedge block away from the wedge-shaped end is a cap end. Along the direction perpendicular to the insertion of the wedge block, the cross-sectional area of ​​the cap end is larger than the cross-sectional area of ​​the wedge-shaped end, and a step is formed at its connection position to accept the dismantling force.

[0013] A second objective of the present invention is to provide a crankshaft heat treatment tolerance control method, utilizing the crankshaft heat treatment tolerance control device as described in the first objective, comprising: Before performing heat treatment, the first constraint fixture is placed in the anti-stretch position of the crankshaft, so that the crank arm is inserted into the constraint hole. The wedge-shaped end of the wedge is inserted into the first constraint groove on the wall of the constraint hole. The wedge is pushed so that it gradually abuts against and presses against the end face of the crank arm through the wedge structure, thereby clamping the crank arm and restricting its outward displacement. Place the constraint block of the second constraint fixture between the two crank arms at the crankshaft anti-shortening position, insert the wedge-shaped end of the wedge into the second constraint groove at the end of the constraint block, push the wedge to abut against and press against the end face of the crank arm, so that the constraint block supports between the two crank arms and restricts their inward contraction; The crankshaft is subjected to vertical hanging quenching and high-temperature tempering with tooling. During this process, the first constraint tooling and the second constraint tooling use physical limits to counteract thermal stress and structural stress, preventing the crankshaft from going out of tolerance. After the heat treatment and cooling are completed, the wedge is removed to release the contact with the crank arm, and then the first and second constraint fixtures are removed.

[0014] Furthermore, before installing the first and second constraint fixtures, clean the crankshaft crank section and the surfaces of the first constraint fixture, the second constraint fixture, and the wedge block.

[0015] Compared with the prior art, the advantages and positive effects of this invention are: To address the technical problem of uncontrollable deformation along the length of crankshafts during vertical hanging heat treatment, leading to insufficient machining allowances or even complete scrapping, the first constraint fixture, through constraint holes for the crank arms to insert, can externally cover or span the crank arms. Combined with wedges, this forms a rigid frame that restricts the outward expansion of the crank arms under gravity, thus locking the spacing between the crank arms during heat treatment and preventing them from elongating due to their own weight. The second constraint fixture features constraint blocks that insert between the crank arms, acting as a solid support within the crank arms. During cooling and contraction, these blocks function as struts. The function of the first and second constraint fixtures is to resist the stress of the crank arm collapsing or converging inward, thereby preventing the crankshaft from shortening. Both the first and second constraint fixtures abut against the crank arm end face by inserting the wedge block into the constraint groove at the wedge end. The wedge-shaped fit structure solves the tolerance fit problem between the fixture and the rough-machined crankshaft. By adjusting the insertion depth of the wedge block, the installation gap can be eliminated, ensuring that the fixture and the crankshaft end face fit tightly, achieving a stable mechanical limit, and the operation is simple. It changes the passive mode of the traditional process of deformation first and then straightening. By applying physical constraints during the heat treatment process, the elongation and shortening deformation of the crankshaft, especially at the sensitive positions at both ends, is effectively controlled.

[0016] The wedge makes stable contact with the crank arm end face through the contact plane, ensuring stability during insertion. The cooperation between the propulsion plane and the reaction plane utilizes the principle of inclined planes to convert the insertion action of the wedge into a vertical clamping force on the crank arm end face. This allows the wedge to apply force precisely in the vertical direction during insertion, avoiding the generation of oblique component forces. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the structure of the first constraint tooling mating with the crankshaft in one or more embodiments of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the second constraint tooling mating with the crankshaft in one or more embodiments of the present invention.

[0020] Figure 3 This is a schematic diagram of the structure of the first constraint tooling in one or more embodiments of the present invention.

[0021] Figure 4 This is a schematic diagram of the structure of the second constraint tooling in one or more embodiments of the present invention.

[0022] Figure 5 This is a schematic diagram of the structure of the chisel in one or more embodiments of the present invention.

[0023] Among them, 10 is the crankshaft; 11 is the crankshaft damper end; 12 is the crankshaft flywheel end; 13 is the crank arm; 20 is the first constraint fixture; 21 is the first base; 22 is the constraint hole; 23 is the first wedge; 24 is the first constraint groove; 30 is the second constraint fixture; 31 is the constraint block; 32 is the second constraint groove; 33 is the second wedge; and 40 is the chisel. Detailed Implementation

[0024] Example 1 In a typical embodiment of the present invention, such as Figures 1-5 As shown, a crankshaft heat treatment deviation control device is presented.

[0025] In the prior art, during the vertical hanging heat treatment process, the crankshaft 10 suffers from uncontrollable elongation or shortening deformation in the length direction due to the lack of effective online constraint methods, resulting in insufficient subsequent machining allowance or direct scrapping. Based on this, this embodiment provides a crankshaft heat treatment deviation control device, comprising a first constraint fixture 20, a second constraint fixture 30, and a wedge block. This changes the passive mode of the traditional "deformation first, straightening later" process. By applying physical constraints during heat treatment, the elongation and shortening deformation of the crankshaft 10 are effectively controlled, ensuring that the length of the crankshaft 10 after heat treatment remains within the allowable range of the process. This avoids both excessive elongation preventing grinding and excessive shortening leading to insufficient finishing allowance, significantly reducing the scrap rate. The wedge block structure not only enables quick assembly and disassembly but also ensures the connection reliability of the fixture under high temperature and repeated heating and cooling environments, preventing fixture loosening and ensuring the stability of the constraint effect.

[0026] Specifically, such as Figures 1-5 As shown, the crankshaft heat treatment tolerance control device mainly includes a first constraint fixture 20, a second constraint fixture 30, and a wedge block.

[0027] The first constraint fixture 20 is mainly a first base 21. A constraint hole 22 for the crank arm 13 to be inserted is provided on the first base 21. A first constraint groove 24 with an opening communicating with the constraint hole 22 is provided on the hole wall of the constraint hole 22. The opening of the first constraint groove 24 faces the end face of the crank arm 13 inserted into the constraint hole 22. The second constraint fixture 30 is mainly a constraint block 31, which can be inserted between the crank arms 13. The constraint block 31 has a second constraint groove 32 on its end along the axial direction of the crankshaft 10. The opening of the second constraint groove 32 faces the end face of the crank arm 13. The wedge has a wedge-shaped end for inserting into the first constraint groove 24 and / or the second constraint groove 32 to abut against the end face of the crank arm 13 and constrain the distance between the crank arms 13. The first wedge 23 is used to cooperate with the first constraint groove 24, and the second wedge 33 is used to cooperate with the second constraint groove 32.

[0028] Depending on the shape and size of the first constraint groove 24 and the second constraint groove 32, the first wedge 23 and the second wedge 33 may adopt the same or different structures. In the following description, the wedge that mates with the first constraint fixture 20 is the first wedge 23, and the wedge that mates with the second fixture is the second wedge 33.

[0029] In this design, the constraint hole 22 of the first constraint fixture 20 allows the crank arm 13 to be inserted. The first constraint groove 24 formed in the wall of the constraint hole 22 faces the end face of the crank arm 13, allowing the wedge to be inserted into the groove according to the end face position and abut against the end face of the crank arm 13, thereby applying pressure along the axial direction of the crankshaft 10 to the crank arm 13. In practical applications, the constraint hole 22 can be square or other cross-sectional shapes adapted to the shape of the crank arm 13, providing a stable receiving space for the crank arm 13 while facilitating the insertion of the wedge.

[0030] The first constraint groove 24 can be formed by machining, such as milling or wire cutting. Its depth and width can be adjusted according to the size of the first wedge 23 to ensure that the first wedge 23 can effectively transmit the force after insertion.

[0031] The constraint block 31 of the second constraint fixture 30 extends between the crank arms 13, and the second constraint groove 32 at its end faces the end face of the crank arm 13, so that the wedge can abut against the end face and transmit the supporting force after insertion. In practical applications, the constraint block 31 can be implemented with an integral structure or a split structure. For example, multiple parts can be combined into the constraint block 31 by welding, bolting or other methods, or an integral structure constraint block 31 can be formed by cutting sheet metal.

[0032] The cross-sectional shape of the second constraint groove 32 can be designed as rectangular, trapezoidal or other geometric shapes that fit the wedge end of the wedge to ensure that the force can be transmitted smoothly when the wedge is inserted.

[0033] Regarding the design of the wedge block, its wedge-shaped end is used to insert into the first constraint groove 24 or the second constraint groove 32. When the wedge block is pushed, it can gradually abut and press against the end face of the crank arm 13 according to the wedge structure. In practical applications, the wedge-shaped end of the wedge block can be manufactured by casting, forging, or machining, and its surface can be provided with anti-slip textures or coatings to enhance friction performance. The pushing direction of the wedge block can be achieved by hand tools, hydraulic devices, or pneumatic devices to meet the operational needs of different scenarios.

[0034] like Figure 1 and Figure 2 As shown, when the crankshaft 10 is hoisted, the crankshaft damper end 11 is usually hoisted. After heat treatment, quenching and cooling, the uppermost crank, which is the first crank near the crankshaft damper end 11, has the largest elongation deformation. During cooling, the lowermost crank, which is the first crank near the crankshaft flywheel end 12, has the fastest shrinkage deformation.

[0035] Through the coordination of the first constraint fixture 20 and the second constraint fixture 30, combined with the physical limiting mechanism of the wedge, the displacement of the crank arm 13 is actively constrained during the heat treatment process to prevent deformation caused by thermal stress and structural stress. Compared with the passive correction method after deformation in the prior art, the crankshaft heat treatment deviation control device provided in this embodiment can pre-constrain the crank arm 13 before heat treatment, thereby avoiding the problem of the upper crank arm elongating due to its own weight and the lower crank arm shortening due to cooling characteristics, which significantly improves the controllability of the heat treatment process.

[0036] Among them, such as Figure 3 As shown, the first constraint fixture 20 is provided with a constraint hole 22 for the crank arm 13 to be inserted. A first constraint groove 24 is provided on the wall of the constraint hole 22, and its opening faces the end face of the crank arm 13 inserted into the constraint hole 22. When the crank arm 13 is inserted into the constraint hole 22, the wedge-shaped end of the wedge can be inserted into the first constraint groove 24, and by pushing the wedge, it gradually abuts against and presses against the end face of the crank arm 13, thereby limiting the outward displacement of the crank arm 13, especially for the elongation deformation of the upper crank due to its own weight during vertical hanging quenching.

[0037] like Figure 4 As shown, the second constraint fixture 30 is provided with a constraint block 31 that inserts between the crank arms 13. The constraint block 31 has a second constraint groove 32 at its end along the axial direction of the crankshaft 10, and its opening also faces the end face of the crank arm 13. When the wedge is inserted into the second constraint groove 32, it is pushed to abut against and press against the end face of the crank arm 13, thereby forming a supporting force between the two crank arms 13, effectively preventing the lower crank from shortening and deforming due to shrinkage stress during the cooling process. The wedge-shaped end of the wedge can smoothly adjust the force according to the insertion depth, ensuring that the pressure applied to the end face of the crank arm 13 is moderate and uniform, thereby achieving dynamic and stable control of the distance between the crank arms 13.

[0038] Furthermore, the first constraint groove 24 and the second constraint groove 32 respectively engage with the wedge-shaped end of the wedge block. Through the contact between the propulsion plane of the wedge structure and the reaction plane within the groove, the insertion motion of the wedge block is converted into a force perpendicular to the end face of the crank arm 13, enhancing the constraint effect. Therefore, the solution provided in this embodiment can actively counteract thermal stress and structural stress during heat treatment, preventing the crankshaft 10 from being deformed due to length deviations, which could affect subsequent machining accuracy or lead to scrapping. It fully considers the actual stress conditions of the crankshaft 10 during heat treatment, ensuring the reliability and effectiveness of the physical limiting mechanism.

[0039] The first constraint fixture 20 controls the tensile deformation of the first crankshaft near the crankshaft damper end 11; the second constraint fixture 30 is installed at the first crankshaft near the crankshaft flywheel end 12 to reduce crankshaft deformation during cooling. The fixture is fixed by adjusting the embedment of the wedge, and the wedge is removed using a chisel 40 after tempering. To avoid the clamping fixture affecting the quenching and cooling effect of the crankshaft 10 itself, a space is designed inside the fixture near the crank arm 13.

[0040] Adjust the position and angle of the first constraint fixture 20 and the second constraint fixture 30, then embed the wedge into the first constraint groove 24 and the second constraint groove 32. Use a hammer to adjust the embedding degree and level of the wedge, and gradually press the wedge in a diagonal sequence to ensure that the wedge is subjected to uniform force and achieve stable fixation and limiting.

[0041] Because the heat treatment fixtures require multiple heating and cooling cycles, strict requirements are placed on the materials. In this embodiment, the first constraint fixture 20, the second constraint fixture 30, and the wedge are made of high-chromium, high-nickel heat-resistant steel Cr25Ni20. The main chemical composition is shown in Table 1. It has good high-temperature resistance and oxidation resistance, can withstand repeated heating below 1000℃, and also has a certain degree of hardness and strength, ensuring wear resistance during use. Cr25Ni20 heat-resistant steel is stable in the furnace, minimizing the adverse effects on the crankshaft 10 itself and the furnace atmosphere.

[0042] Table 1. Main Chemical Components of Cr25Ni20

[0043] like Figure 1 and Figure 3As shown, the first constraint fixture 20 has two spaced-apart constraint holes 22 for different crank arms 13 to insert into. Each constraint hole 22 has a first constraint groove 24. The first constraint fixture 20 has a U-shaped structure. The first constraint fixture 20 is a device for physically limiting the spacing between the crank arms 13 during the heat treatment of the crankshaft 10. It is made of heat-resistant steel to meet the requirements of use in high-temperature environments. The two spaced-apart constraint holes 22 allow the first constraint fixture 20 to constrain multiple crank arms 13 simultaneously. The design for different crank arms 13 to insert into ensures that the device can constrain crank arms 13 at different positions on the crankshaft 10, and the position of the first constraint fixture 20 is locked by utilizing the relative positions between multiple crank arms 13, adapting to the characteristics of multiple crank deformation during heat treatment. The first constraint groove 24 provides insertion space for the wedge and guides its direction of action.

[0044] Each constraint hole 22 is provided with a first constraint groove 24, allowing the wedge to be inserted independently and act on each crank arm 13. This not only improves the targeting of the constraint force application but also enhances the overall efficiency and precision of the device. Furthermore, by providing two constraint holes 22 on the first constraint fixture 20, the structural characteristics of the crankshaft 10 can be better adapted, thereby resisting thermal stress and structural stress during heat treatment and preventing the crankshaft 10 from affecting subsequent processing due to excessive deformation.

[0045] like Figure 3 As shown, at least two first constraint grooves 24 are provided on the same side of the crank arm 13 end face within the constraint hole 22, and at least two wedges located within the first constraint grooves 24 abut against the same crank arm 13 end face within the constraint hole 22. The first constraint grooves 24 can be implemented using straight, arc-shaped, or other geometric structures adapted to the shape of the crank arm 13 end face. By setting multiple first constraint grooves 24, the local pressure under thermal stress is dispersed, avoiding deformation caused by insufficient constraint at a single point. The wedges can be inserted into the first constraint grooves 24 and abut against the crank arm 13 end face; they are also made of metal or other high-temperature resistant and high-strength materials to ensure a stable physical limiting effect during heat treatment.

[0046] By providing at least two first constraint grooves 24 on the same side of the crank arm 13 end face within the constraint hole 22, and cooperating with at least two wedges, multi-point contact and uniform force application are achieved. The distribution of multiple first constraint grooves 24 creates multiple constraint points in the same area of ​​the crank arm 13 end face, effectively dispersing local pressure under thermal stress. Simultaneously, multiple wedges are inserted into the corresponding first constraint grooves 24 and abut against the crank arm 13 end face, forming multi-point support for the crank arm 13 end face and enhancing the overall constraint strength. This not only solves the problem of insufficient or uneven constraint force that may be caused by a single constraint groove, but also improves the stability of the crankshaft 10 during heat treatment, preventing displacement or shrinkage of the crank arm 13.

[0047] like Figure 3 As shown, the constraint hole 22 has first constraint grooves 24 on both sides of the crank arm 13 into which it is inserted. A gap is left between the first constraint groove 24 and the end face of the crank arm 13 it faces, providing an insertion path for the wedge and ensuring that pressure is evenly distributed when constraint force is applied from both sides of the crank arm 13. Furthermore, the gap refers to the reserved space between the first constraint groove 24 and the end face of the crank arm 13, which can be achieved by adjusting the groove depth or the wedge size. This allows for adaptation to thermal expansion or contraction during heat treatment and reduces stress concentration caused by excessive constraint.

[0048] The first constraint grooves 24 on both sides of the constraint hole 22 can respectively cooperate with the wedge to apply constraint force from both sides of the crank arm 13 simultaneously, thereby avoiding twisting or local stress concentration caused by unilateral force.

[0049] like Figure 3 As shown, the first constraint fixture 20 and the second constraint fixture 30 have arc-shaped surfaces that adapt to the journal on the journal side. The first constraint fixture 20, the second constraint fixture 30, and the wedge are made of heat-resistant steel. The arc-shaped surface is a curved surface structure that matches the shape of the outer surface of the journal. It can be achieved by using a circular arc-shaped groove formed by precision machining, which can ensure a tight fit between the fixture and the journal and reduce constraint failure caused by gaps.

[0050] like Figure 4 As shown, at least two spaced-apart second constraint grooves 32 are respectively opened at both ends of the second constraint fixture 30, and wedges are respectively fitted therewith. At least two wedges located at the same end abut against the same end face of the crank arm 13. The second constraint groove 32 is a groove structure opened at the end of the second constraint fixture 30 to accommodate the wedges. It can be implemented in the form of a straight groove, an arc, or other groove form adapted to the shape of the end face of the crank arm 13. The multi-point distributed groove design ensures uniform coverage of the constraint force.

[0051] The multiple, spaced-apart second constraint grooves 32 prevent localized stress concentration when engaging the wedges, thus improving the overall constraint effect. The simultaneous action of multiple wedges at the same end enhances the distribution density and reliability of the constraint force, preventing individual wedge failure or loosening, thereby ensuring stable support for the crank arm 13 end face. This not only enhances the distribution density of the constraint force but also improves the overall constraint reliability. Even if individual wedges loosen or fail, effective support for the crank arm 13 is maintained, effectively counteracting the inward contraction deformation of the crank arm 13 caused by thermal and structural stresses. This solves the problem of unstable constraint force caused by insufficient or uneven distribution of constraint grooves and wedges.

[0052] like Figures 1-4As shown, the wedge-shaped end of the wedge abuts against one side of the end face of the crank arm 13, which is a contact plane parallel to its insertion direction. The wedge-shaped end abuts against one side of the first constraint groove 24 or the second constraint groove 32, which is a propulsion plane inclined relative to the contact plane. The first constraint groove 24 and the second constraint groove 32 are provided with reaction planes that conform to the propulsion plane, so as to control the wedge to apply a force to the end face of the crank arm 13 in the direction perpendicular to the end face of the crank arm 13.

[0053] Specifically, the contact plane refers to the part where the wedge-shaped end of the wedge contacts the end face of the crank arm 13. This can be achieved using a precision-machined planar structure, ensuring stable surface contact between the wedge and the crank arm 13 end face during insertion, preventing slippage or deflection due to oblique contact. The propulsion plane is the inclined surface where the wedge-shaped end contacts the first constraint groove 24 or the second constraint groove 32. It is an inclined structure with a specific angle, utilizing the principle of the inclined plane to convert the insertion force into a clamping force on the crank arm 13. The reaction plane refers to the plane set on the first constraint groove 24 and the second constraint groove 32 that closely fits the propulsion plane. This can be achieved by machining a precisely matched plane within the groove, ensuring that the propulsion force is effectively transmitted and a reaction force is generated, thereby precisely controlling the force transmission path.

[0054] The wedge makes stable contact with the end face of crank arm 13 through the contact plane, ensuring stability during insertion. The cooperation between the propulsion plane and the reaction plane utilizes the principle of inclined planes to convert the insertion action of the wedge into a vertical clamping force on the end face of crank arm 13, so that the wedge can apply force precisely in the vertical direction during insertion, avoiding the generation of oblique component force.

[0055] like Figure 3 and Figure 4 As shown, the end of the wedge block away from the wedge-shaped end is the cap end. Along the direction perpendicular to the insertion of the wedge block, the cross-sectional area of ​​the cap end is larger than that of the wedge-shaped end, and a step is formed at its connection point to accept the demolition force.

[0056] The cap end is the area at the end of the wedge block furthest from the wedge-shaped end, specifically designed for applying demolition force. It can be implemented using a planar structure, a boss structure, or other geometry that facilitates tool clamping. Its purpose is to provide a clear and stable force-bearing point, ensuring effective transmission of external force during demolition. The cap end has a larger cross-sectional area than the wedge-shaped end to increase the contact area, thereby dispersing stress and improving force application stability, preventing localized stress concentration that could damage the wedge block. Furthermore, the step formed at the connection point can be understood as a mechanical stop structure, specifically formed through machining processes such as cutting or casting. Its purpose is to prevent the application tool from slipping, ensuring that the demolition force is effectively transmitted in the predetermined direction.

[0057] The cap end, serving as a dedicated force-bearing area, is functionally separated from the wedge end, allowing the operator or tool to accurately locate the point of force application, thereby simplifying the removal process. Figure 5 As shown, the cap end can cooperate with the chisel 40 to receive the force of the chisel 40 with a wedge structure, so that the wedge end can be pulled out from the constraint groove, realizing the process of removing the wedge from the first constraint fixture 20 and the second constraint fixture 30. This solves the problem of uneven force or difficulty in applying force during the removal of the wedge, and also significantly improves the operability and service life of the device, providing a reliable guarantee for the out-of-tolerance control during the heat treatment process of the crankshaft 10.

[0058] Example 2 In another typical embodiment of the present invention, such as Figures 1-5 As shown, a method for controlling crankshaft heat treatment tolerances is presented, utilizing the crankshaft heat treatment tolerance control device as described in Example 1, including the following steps: Before performing heat treatment, the first constraint fixture 20 is set in the anti-stretch position of the crankshaft 10, so that the crank arm 13 is inserted into the constraint hole 22. The wedge-shaped end of the wedge is inserted into the first constraint groove 24 on the wall of the constraint hole 22. The wedge is pushed so that it gradually abuts against and presses against the end face of the crank arm 13 through the wedge structure, thereby clamping the crank arm 13 and restricting its outward displacement. Place the constraint block 31 of the second constraint fixture 30 between the two crank arms 13 at the anti-shortening position of the crankshaft 10, insert the wedge-shaped end of the wedge into the second constraint groove 32 at the end of the constraint block 31, push the wedge to abut against and press against the end face of the crank arm 13, so that the constraint block 31 is supported between the two crank arms 13, restricting their inward contraction. The crankshaft 10 is subjected to vertical hanging quenching and high-temperature tempering with tooling. During this process, the first constraint tooling 20 and the second constraint tooling 30 use physical limits to resist thermal stress and structural stress, preventing the crankshaft 10 from going out of tolerance. After the heat treatment and cooling are completed, the wedge is removed to release the contact with the crank arm 13, and then the first and second constraint fixtures 30 are removed.

[0059] Furthermore, before installing the first constraint fixture 20 and the second constraint fixture 30, clean the crankshaft 10 crank section and the surfaces of the first constraint fixture 20, the second constraint fixture 30 and the wedge block.

[0060] The corresponding wedges are respectively embedded into the first constraint groove 24 or the second constraint groove 32 of the first constraint fixture 20 or the second constraint fixture 30, and the wedges are gradually pressed in a diagonal order. The embedding degree of the wedges is adjusted by hammering to ensure that the wedges are not loose or have gaps in the constraint grooves. The position and angle of the first constraint fixture 20 or the second constraint fixture 30 are detected by a level, so that the side of the first constraint fixture 20 away from the crankshaft 10 axis is flush with the outer peripheral plane section of the crank arm 13, and the side of the second constraint fixture 30 away from the crankshaft 10 axis is flush with the outer peripheral plane section of the crank arm 13, so as to play a role in fixing and stabilizing.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A crankshaft heat treatment tolerance control device, characterized in that, include: The first constraint fixture has a constraint hole for the crank arm to be inserted into. The wall of the constraint hole has a first constraint groove that opens to communicate with the constraint hole. The opening of the first constraint groove faces the end face of the crank arm inserted into the constraint hole. The second constraint fixture is provided with a constraint block that extends between the crank arms. A second constraint groove is provided on the end of the constraint block along the crankshaft axis, and the opening of the second constraint groove faces the end face of the crank arm. The wedge has a wedge-shaped end for inserting into the first constraint groove and / or the second constraint groove to abut against the end face of the crank arm and constrain the crank arm spacing.

2. The crankshaft heat treatment tolerance control device as described in claim 1, characterized in that, The first constraint fixture has two spaced constraint holes for different crank arms to insert into, and each constraint hole has a first constraint groove.

3. The crankshaft heat treatment tolerance control device as described in claim 2, characterized in that, At least two first constraint grooves are provided on the same side of the crank arm end face inside the constraint hole, and at least two wedges located in the first constraint grooves abut against the same crank arm end face inside the constraint hole.

4. The crankshaft heat treatment tolerance control device as described in claim 2 or 3, characterized in that, The constraint hole corresponds to the first constraint groove on both sides of the crank arm that are inserted into it, and a gap is left between the first constraint groove and the crank arm end face that it faces.

5. The crankshaft heat treatment tolerance control device as described in claim 1, characterized in that, The first constraint fixture and the second constraint fixture have an arc surface on the side facing the journal to adapt to the journal. The first constraint fixture, the second constraint fixture and the wedge are made of heat-resistant steel.

6. The crankshaft heat treatment tolerance control device as described in claim 1, characterized in that, The second constraint fixture has at least two spaced second constraint grooves at both ends, and each groove is fitted with a wedge. At least two wedges at the same end abut against the same crank arm end face.

7. The crankshaft heat treatment tolerance control device as described in claim 1, characterized in that, The wedge-shaped end of the wedge abuts against the end face of the crank arm on one side, which is a contact plane parallel to its insertion direction. The wedge-shaped end abuts against the first constraint groove or the second constraint groove on one side, which is a propulsion plane inclined relative to the contact plane. The first constraint groove and the second constraint groove are provided with reaction planes that conform to the propulsion plane, so as to control the wedge to apply a force to the end face of the crank arm in the direction perpendicular to the end face of the crank arm.

8. The crankshaft heat treatment tolerance control device as described in claim 7, characterized in that, The end of the wedge block away from the wedge-shaped end is the cap end. Along the direction perpendicular to the insertion of the wedge block, the cross-sectional area of ​​the cap end is larger than that of the wedge-shaped end, and a step is formed at its connection position to accept the dismantling force.

9. A method for controlling crankshaft heat treatment deviations, characterized in that, The crankshaft heat treatment tolerance control device according to any one of claims 1-8 comprises: Before performing heat treatment, the first constraint fixture is placed in the anti-stretch position of the crankshaft, so that the crank arm is inserted into the constraint hole. The wedge-shaped end of the wedge is inserted into the first constraint groove on the wall of the constraint hole. The wedge is pushed so that it gradually abuts against and presses against the end face of the crank arm through the wedge structure, thereby clamping the crank arm and restricting its outward displacement. Place the constraint block of the second constraint fixture between the two crank arms at the crankshaft anti-shortening position, insert the wedge-shaped end of the wedge into the second constraint groove at the end of the constraint block, push the wedge to abut against and press against the end face of the crank arm, so that the constraint block supports between the two crank arms and restricts their inward contraction; The crankshaft is subjected to vertical hanging quenching and high-temperature tempering with tooling. During this process, the first constraint tooling and the second constraint tooling use physical limits to counteract thermal stress and structural stress, preventing the crankshaft from going out of tolerance. After the heat treatment and cooling are completed, the wedge is removed to release the contact with the crank arm, and then the first and second constraint fixtures are removed.

10. The crankshaft heat treatment deviation control method as described in claim 9, characterized in that, Before installing the first and second constraint fixtures, clean the crankshaft crank section and the surfaces of the first constraint fixture, the second constraint fixture, and the wedge.

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