A device and method for aligning the crankshaft's crank axis relative to its major axis.

Abstract

This invention provides a device and method for aligning the crankshaft's crank axis relative to the major axis. The bottom of the alignment block has alignment screws and alignment springs connected to both sides of a clearance groove. The alignment block is fixed to the side of the alignment rod near the bottom and facing the V-block, such that when the crankshaft is placed on the V-block and the side of the alignment rod near the alignment block is tangent to the crankshaft crank, the clearance groove of the alignment block perfectly covers the crankshaft balance block. The alignment screws and alignment springs are located on the parting surfaces on both sides of the balance block. The diameter of the reference shaft is the same as the diameter of the crankshaft crank, and the axis of the reference shaft is aligned relative to the major axis. The alignment module pre-fixes the position where the alignment rod is tangent to the crankshaft crank, and then determines the downward stroke of the alignment rod. The alignment of the crank axis relative to the major axis is achieved through the alignment rod and the alignment block, resulting in accurate and efficient alignment.

Description

Technical Field

[0001] This invention relates to the field of crankshaft machining technology, and more specifically to a device and method for aligning the crankshaft crank axis relative to the long axis. Background Technology

[0002] The crankshaft is a key component in compressors that transmit torque. Its eccentricity and precision directly affect the compressor's performance and operational smoothness. A single-support crankshaft consists of a major shaft, cranks, and a counterweight. The crankshaft eccentricity refers to the distance between the centerline (axis) of the cranks and the centerline of rotation of the crankshaft (i.e., the axis of the major shaft). In actual production, the optimal crankshaft eccentricity is usually calculated and tested based on the compressor's design requirements and operating conditions. Then, based on the crankshaft dimensions and eccentricity, mass production and machining of the crankshafts are carried out. Grinding the outer cylindrical surface of the cranks is a crucial step in the crankshaft production process; currently, this grinding can be performed using a cranks grinding machine.

[0003] During crankshaft outer cylindrical surface grinding, the crankshaft is transported to the fixture on the crankshaft grinding machine by a robotic arm for positioning and clamping. However, when the crankshaft is placed on the fixture, it is impossible to ensure that the crankshaft axis and the long shaft axis coincide on the vertical plane of the balance block parting surface. That is, the crankshaft axis is not "aligned" relative to the long shaft axis, resulting in insufficient roughing allowance for grinding the outer cylindrical surface of the crankshaft, i.e., incomplete grinding, causing waste and defective products to be rejected. Therefore, it is highly anticipated by those skilled in the art to provide a device that can align the crankshaft axis with the long shaft axis, assisting the grinding machine in grinding the outer cylindrical surface of the crankshaft to a white state and reducing the rejection of defective products. Summary of the Invention

[0004] This invention provides a device and method for aligning the crankshaft's crank axis relative to the long axis. The alignment device uses a calibration module to pre-fix the position where the alignment rod is tangent to the crankshaft crank. Then, based on the crankshaft crank position, eccentricity requirements, and trial grinding, the downward stroke of the alignment rod is determined. By using the alignment rod and alignment block, the crank axis is aligned with the long axis when the crankshaft is clamped, resulting in accurate and efficient alignment.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A device for aligning the crankshaft's crank axis relative to its major axis is mounted on a crankshaft grinding machine. The grinding machine has a fixture comprising a detachably connected V-block and a pressure plate. The major axis of the crankshaft is placed on the V-block and clamped by the pressure plate. The alignment device includes:

[0007] The centering module includes a centering rod and a centering block. The centering rod is vertically mounted on a crank grinding machine so that when the crankshaft is placed on the V-block, the centering rod is exactly above the crankshaft crank, and the vertical and horizontal positions of the centering rod are adjustable. The centering block has a relief groove in the middle facing downwards. A centering screw and a centering spring are respectively connected to the two sides of the relief groove at the bottom of the centering block. The length of the centering screw protruding from the bottom of the centering block is the same as the length of the centering spring protruding from the bottom of the centering block in its free state, and the lengths of both the centering screw and the centering spring protruding from the bottom of the centering block are adjustable. The centering block is fixed to the side of the centering rod near the bottom and facing the V-block on one side of the relief groove, so that when the crankshaft is placed on the V-block and the side of the centering rod near the centering block is tangent to the crankshaft crank, the relief groove of the centering block just covers the crankshaft balance block, and the centering screw and the centering spring are respectively located on the parting surface on both sides of the balance block.

[0008] The calibration module includes a calibration block and a reference shaft. The calibration block is detachably mounted on the suspended end of the V-block. The diameter of the reference shaft is the same as the diameter of the crankshaft crank. The reference shaft is horizontally connected to the calibration block and extends from the end face of the calibration block away from the V-block. The end face of the reference shaft away from the V-block extends beyond the end face of the centering rod facing the V-block. When the crankshaft is placed on the V-block, the axis of the reference shaft is aligned with the axis of the long shaft.

[0009] The crank grinding machine is equipped with a connecting seat, on which a telescopic cylinder is vertically fixed. The telescopic rod of the telescopic cylinder is vertically downward and moves up and down relative to the cylinder body. The centering rod is installed on the telescopic rod of the cylinder and moves up and down with the telescopic rod of the cylinder.

[0010] The crank grinding machine is equipped with a positioning plate, on which a flat key is installed horizontally. The upper end of the centering rod passes through the flat key and slides along it. A left adjusting plate and a right adjusting plate are fixed on both sides of the centering rod on the positioning plate. Both the left and right adjusting plates are provided with threaded holes, and adjusting screws are connected to the threaded holes. The two adjusting screws are respectively placed on the two sides of the centering rod. The centering rod is adjusted left and right by turning the adjusting screws. After the position adjustment is completed, the adjusting screws on both sides are tightened to lock the centering rod.

[0011] The correction block includes a connecting plate and a mounting plate. The connecting plate is C-shaped and is sandwiched from both sides onto the end face of the V-shaped block at one of its suspended ends. The mounting plate is integrally connected to the connecting plate and is located at the top center of the connecting plate. The mounting plate is provided with mounting holes, and the reference shaft is connected to the mounting holes.

[0012] One end of the reference shaft is connected to a connecting shaft, which is detachably connected to the mounting hole, allowing the reference shaft to protrude from the end face of the calibration block away from the V-block.

[0013] The centering block is provided with threaded holes at the mounting positions of the centering screw and the centering spring. The threaded holes on both sides are respectively matched with the threads of the centering screw and the centering spring. The centering screw and the centering spring are connected to the threaded holes by threads and the length of the centering screw and the centering spring exposed at the bottom of the centering block is adjusted.

[0014] The centering screw is located on the side of the centering block closest to the centering rod.

[0015] The present invention also provides a method for aligning the crankshaft's crank axis relative to the major axis of the crankshaft using an alignment device, comprising the following steps:

[0016] (1) Install the alignment block with the reference axis installed on the V block, adjust the position of the centering rod up and down and left and right so that the side of the centering rod close to the centering block is tangent to the reference axis, lock the left and right position of the centering rod, and remove the alignment block from the V block.

[0017] (2) Move the centering rod upwards to the initial height position;

[0018] (3) Determine the downward stroke of the centering rod so that when the centering rod moves from the initial height position to the final height position according to the downward stroke, the centering screws and centering springs on both sides of the centering block press on the parting surfaces on both sides of the balance block respectively, and the side of the centering rod is tangent to the outer circle of the crankshaft crank.

[0019] (4) Place the long shaft of the crankshaft to be processed on the V-block, and move the centering rod from the initial height position to the final height position according to the downward stroke of the centering rod;

[0020] (5) Use the pressure plate to lock the long shaft of the crankshaft and move the centering rod up to the initial height position.

[0021] If the size of the next crankshaft to be processed is the same as that of the previous crankshaft to be processed, then start centering the next crankshaft to be processed directly from step (3); if the size of the next crankshaft to be processed is different from that of the previous crankshaft to be processed, after the previous crankshaft to be processed is completed, select a reference shaft that is consistent with the crankshaft size of the next crankshaft to be processed, and then start centering the next crankshaft to be processed from step (1).

[0022] The specific steps for determining the downward stroke of the centering rod in step (3) are as follows: (3.1) Calculate the theoretical downward stroke of the centering rod based on the crankshaft crank position and eccentricity requirements;

[0023] (3.2) Place the long shaft of the crankshaft to be processed on the V-block. According to the theoretical downward stroke of the centering rod, move the centering rod from the initial height position to the final height position. Lock the long shaft of the crankshaft with the pressure plate and move the centering rod back to the initial height position.

[0024] (3.3) Perform trial grinding on a crank grinder. Based on the symmetry of the crank after grinding and the grinding quality, confirm whether the centering position meets the processing requirements. If it meets the requirements, no adjustment is needed, and the downward stroke of the centering rod is the theoretical downward stroke of the centering rod. If it does not meet the requirements, continue to adjust the downward stroke of the centering rod until the trial grinding meets the requirements.

[0025] Compared with the prior art, the beneficial effects of the present invention are: (1) The device for aligning the crankshaft crank axis relative to the long axis provided by the present invention includes an alignment module and a correction module. The alignment module fixes the position where the alignment rod is tangent to the crankshaft crank in advance. Then, the downward stroke of the alignment rod is determined according to the crankshaft crank position and eccentricity requirements and trial grinding. When the crankshaft is clamped, the crank axis is aligned with the long axis through the alignment rod and the alignment block. The alignment is accurate and efficient.

[0026] (2) The calibration module in this invention includes a calibration block and a reference shaft. The diameter of the reference shaft is the same as the diameter of the crank, and the position of the reference shaft is aligned with the long shaft. After the calibration module fixes the position where the centering rod is tangent to the crankshaft crank in advance, it is only necessary to adjust the crank to be tangent to the centering rod in the later stage to achieve the alignment of the crank axis with the long shaft axis. The alignment method is simple and fast. The calibration block and the reference shaft are detachably connected, and the reference shaft of different sizes can be replaced according to the crankshaft of different sizes to meet various processing parameters.

[0027] (3) The centering module in this invention includes a centering rod and a centering block. The centering block is provided with a centering bolt and a centering spring. During the lowering process of the centering rod, when the centering screw or the centering spring contacts the parting surface on both sides of the balance block, the centering screw and the centering spring respectively push the crankshaft to rotate in the clockwise or counterclockwise direction, so that the outer circle of the crank is always positioned against the upper corner of the side of the centering rod. When the side of the centering rod is tangent to the outer circle of the crankshaft crank, under the resistance of the centering rod and the rebound force of the spring, the crankshaft crank axis is ensured to be aligned with the long axis axis, thereby completing the centering of the crankshaft. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the existing crankshaft structure;

[0029] Figure 2 This is a schematic diagram of the crankshaft being fixed on the fixture in this invention;

[0030] Figure 3 This is a partial structural diagram of the centering module in this invention;

[0031] Figure 4 This is a schematic diagram showing the connection between the centering rod and the centering block in this invention;

[0032] Figure 5This is a schematic diagram showing the connection between the correction module and the V-block in this invention;

[0033] Figure 6 This is a schematic diagram of the structure of the correction block in this invention;

[0034] Figure 7 This is a schematic diagram of the reference shaft in this invention;

[0035] Figure 8 This is a three-dimensional structural diagram of the centering rod when it is tangent to the reference axis in this invention;

[0036] Figure 9 This is a front view of the centering rod when it is tangent to the reference axis in this invention;

[0037] Figure 10 This is a schematic diagram of the centering module and crankshaft mounted on a lathe in this invention;

[0038] Figure 11 This is a schematic diagram of the centering rod moving down to the end position in this invention;

[0039] In the diagram: 1-crankshaft, 11-long shaft, 12-crank crank, 13-balance block, 21-V-block, 22-pressure plate, 3-crank crank grinder, 41-centering rod, 42-centering block, 421-leaving groove, 422-centering screw, 423-centering spring, 43-connecting seat, 44-telescopic cylinder, 45-connecting plate, 46-positioning plate, 47-flat key, 48-left adjusting plate, 49-right adjusting plate, 51-correction block, 511-connecting plate, 512-mounting plate, 52-reference shaft, 521-connecting shaft. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] The structure of the crankshaft in this invention is as follows: Figure 1 As shown, it includes a major axis 11, a crank 12, and a balance weight 13, as follows: Figure 1 As shown. The crankshaft structure is a conventional existing structure, and its parameters will not be described in detail here.

[0042] During the grinding of the outer cylindrical surface of the crankshaft, the crankshaft is transported by a robotic arm to a fixture on the crankshaft grinding machine 3 for positioning and clamping. Specifically, the fixture includes a detachably connected V-block 21 and a pressure plate 22. During crankshaft installation, the robotic arm places the long shaft of the crankshaft on the V-block. After the crankshaft position is adjusted, the pressure plate presses it onto the long shaft of the crankshaft, thereby clamping the crankshaft. Figure 2As shown, the outer cylindrical surface of the crankshaft is then ground. Specifically, one end of the V-block of the fixture is fixedly mounted to the bearing seat of the rotating component on the crankshaft grinding machine by screws, while the other end of the V-block is suspended. During grinding, the rotating component drives the crankshaft to rotate, thus grinding the outer cylindrical surface of the crankshaft. The crankshaft grinding machine and fixture are existing technologies and will not be described in detail here.

[0043] However, when the crankshaft is placed on the V-block, it cannot be ensured that the crankshaft axis and the long shaft axis coincide on the vertical plane of the parting surface of the balance block. That is, the crankshaft axis is not "aligned" relative to the long shaft axis, resulting in the crankshaft not being ground properly and a high defect rate. Therefore, this embodiment provides a device for aligning the crankshaft axis with the long shaft axis, ensuring that the crankshaft axis is "aligned" with the long shaft axis and reducing the number of defective products.

[0044] The device provided in this embodiment for aligning the crankshaft's crank axis relative to the long axis includes an alignment module and a correction module.

[0045] The centering module includes a centering rod 41 and a centering block 42. The centering rod is vertically mounted on a crank grinding machine so that when the crankshaft is placed on the V-block, the centering rod is positioned exactly above the crankshaft crank. The vertical and horizontal positions of the centering rod are adjustable. Figure 3 As shown. Specifically, a connecting seat 43 is fixed on the crank grinder, and a telescopic cylinder 44 is vertically fixed on the connecting seat. The telescopic rod of the telescopic cylinder is vertically downward and moves up and down relative to the cylinder body. A connecting plate 45 is fixed to the bottom end of the telescopic rod of the cylinder. A positioning plate 46 is fixed on the connecting plate, and a flat key 47 is installed on the positioning plate in the horizontal direction. The upper end of the centering rod passes through the flat key and slides along the flat key. A left adjusting plate 48 and a right adjusting plate 49 are fixed on both sides of the centering rod on the positioning plate. Both the left and right adjusting plates are provided with threaded holes, and adjusting screws are connected in the threaded holes. The two adjusting screws are respectively placed on the two sides of the centering rod. By turning the adjusting screws, the centering rod can be moved left and right. After the position adjustment is completed, the adjusting screws on both sides are locked to lock the centering rod, thereby locking the left and right position of the centering rod.

[0046] A clearance groove 421 is provided in the center of the middle block facing downwards, such as... Figure 4As shown, in this embodiment, a centering screw 422 and a centering spring 423 are respectively connected to both sides of the bottom of the centering block located in the clearance groove. The length of the centering screw protruding from the bottom of the centering block is the same as the length of the centering spring protruding from the bottom of the centering block in its free state (i.e., the centering spring is neither compressed nor stretched). In this embodiment, the lengths of both the centering screw and the centering spring protruding from the bottom of the centering block are adjustable to meet the centering requirements during the machining of crankshafts of different sizes. Specifically, the centering block is provided with threaded holes at the mounting locations of the centering screw and the centering spring. The threaded holes on both sides are respectively matched with the threads of the centering screw and the centering spring. The centering screw and the centering spring are connected to the threaded holes through threads, and the lengths of the centering screw and the centering spring protruding from the bottom of the centering block are adjusted.

[0047] The centering block is fixed to the side of the centering rod near the bottom and facing the V-block (i.e., the centering block and the centering rod are offset) on one side of the clearance groove. This ensures that when the crankshaft is placed on the V-block and the side of the centering rod near the centering block is tangent to the crankshaft crank, the clearance groove of the centering block just covers the crankshaft balance block. The centering screw and centering spring are located on the parting surfaces on both sides of the balance block. Specifically, the centering rod and the centering block are fixed by locking screws. In this embodiment, the centering screw is located on the side of the centering block near the centering rod. During the downward movement of the centering rod, the centering screw presses against the parting surface on one side of the balance block, causing the outer surface of the crank to face the side of the centering rod. The centering spring presses against the parting surface on the other side of the balance block, causing the outer surface of the crank to face away from the side of the centering rod. This ensures that the outer circle of the crank is always positioned against the upper corner of the side of the centering rod until the outer circle of the crank is tangent to the side of the centering rod, thus completing the centering. Specifically, the structure of the clearance groove matches the upper structure of the crankshaft balance block, allowing the centering block to sit on top of the balance block during the downward movement of the centering rod, so that the centering screws and centering springs on both sides of the centering block can press against the parting surface on both sides of the balance block.

[0048] The calibration module includes a calibration block 51 and a reference shaft 52. The calibration block is detachably mounted on the suspended end of the V-block (the end opposite to the mounting end face of the V-block). The diameter of the reference shaft is the same as the diameter of the crankshaft crank. The reference shaft is horizontally connected to the calibration block and extends from the end face of the calibration block opposite to the V-block. The end face of the reference shaft away from the V-block extends beyond the end face of the centering rod facing the V-block, ensuring that when adjusting the left and right position of the centering rod using the calibration block and the reference shaft, the centering rod can be tangent to the reference shaft from one side. When the crankshaft is placed on the V-block, the axis of the reference shaft is aligned relative to the axis of the major shaft. Figure 5 As shown. Specifically, the calibration block includes a connecting plate 511 and a mounting plate 512, as shown. Figure 6As shown, the connecting plate is C-shaped and clamps onto the end face of the V-block's suspended end from both sides. Furthermore, the connecting plate and the two sides of the V-block are detachably connected by screws. The mounting plate is integrally connected to the connecting plate and located at the top center of the connecting plate. The mounting plate has mounting holes 513, and the reference shaft is connected to these mounting holes. Specifically, one end of the reference shaft is integrally connected to a connecting shaft 521, as shown... Figure 7 As shown, the connecting shaft is detachably connected to the mounting hole, allowing the reference shaft to protrude from the end face of the correction block away from the V-block. Preferably, the connecting shaft and the mounting hole are connected by a threaded engagement, thereby allowing the reference shaft to be removed from the mounting plate, ensuring that reference shafts of different sizes can be replaced to meet the needs of crankshafts of different sizes.

[0049] The alignment method provided by this invention for aligning the crankshaft's crank axis relative to the major axis includes the following steps:

[0050] (1) Install the alignment block with the reference axis installed onto the V-block, and adjust the position of the centering rod up and down and left and right so that the side of the centering rod near the centering block is tangent to the reference axis. Figure 8 and Figure 9 As shown, the left and right positions of the centering rod are locked by locking the adjusting screws on the left and right adjusting plates;

[0051] Since the reference axis is aligned with the major axis, and the reference axis has the same diameter as the crank, after locking the position of the centering rod in the left and right directions, it is only necessary to adjust the crank to be tangent to the centering rod to achieve alignment of the crank axis with the major axis.

[0052] (2) Remove the correction block from the V-block and move the centering rod upward to the initial height position. The initial height position of the centering rod can be set as needed, as long as it does not affect the grinding of the outer surface of the crankshaft crank in the later stage.

[0053] It should be noted that when machining the outer cylindrical surface of the crankshaft of the same size in the same batch, that is, when the size of the next crankshaft to be machined is the same as that of the previous crankshaft, it is not necessary to determine the left and right positions of the centering rod again through the correction block and the reference shaft. That is, steps (1) and (2) are not required, and the centering of the next crankshaft to be machined can be started directly from step (3). However, when the size of the crankshaft to be machined is different, that is, when the size of the next crankshaft to be machined is different from that of the previous crankshaft, after the previous crankshaft to be machined is completed, a reference shaft with the same crankshaft size as the next crankshaft to be machined is selected, and the left and right positions of the centering rod are calibrated again starting from step (1) to complete the centering step of the next crankshaft to be machined.

[0054] (3) Determine the downward stroke of the centering rod so that when the centering rod moves from the initial height position to the final height position according to the downward stroke, the centering screws and centering springs on both sides of the centering block press against the parting surfaces on both sides of the balance block, and the side of the centering rod is tangent to the outer circle of the crankshaft crank. Figure 11 As shown;

[0055] During the downward movement of the centering rod, when the centering screw or centering spring contacts the parting surfaces on both sides of the balance block, the centering screw and centering spring respectively push the crankshaft to rotate clockwise or counterclockwise, ensuring that the outer surface of the crank is always positioned against the upper corner of the centering rod side. When it moves to the final height position, the side of the centering rod is tangent to the outer circle of the crankshaft crank. Under the resistance of the centering rod and the rebound force of the spring, the crankshaft crank axis is ensured to be aligned with the long axis axis, thus completing the crankshaft alignment. In other words, after determining the downward stroke of the centering rod, for crankshafts of the same size, the crank alignment is completed when the centering rod moves to the final height position. The alignment method is simple and fast. It should be noted that after determining the downward stroke of the centering rod, the height that the centering rod needs to move downward each time is fixed when aligning crankshafts of the same size, and no further adjustments are needed, ensuring the accuracy and consistency of the machining.

[0056] Specifically, the steps for determining the downward stroke of the centering rod are as follows:

[0057] (3.1) Calculate the theoretical downward stroke of the centering rod based on the crankshaft crank position and eccentricity requirements;

[0058] (3.2) Place the long shaft of the crankshaft to be processed on the V-block. According to the theoretical downward stroke of the centering rod, move the centering rod from the initial height position to the final height position. Lock the long shaft of the crankshaft with the pressure plate and move the centering rod back to the initial height position.

[0059] (3.3) Perform trial grinding on a crank grinder. Based on the symmetry of the crank after grinding and the grinding quality, confirm whether the centering position meets the processing requirements. If it meets the requirements, no adjustment is needed, and the downward stroke of the centering rod is the theoretical downward stroke of the centering rod. If it does not meet the requirements, continue to adjust the downward stroke of the centering rod until the trial grinding meets the requirements.

[0060] (4) Place the long shaft of the crankshaft to be machined on the V-block, such as... Figure 10 As shown, based on the downward stroke of the centering rod, the centering rod is moved from the initial height position to the final height position;

[0061] Specifically, after the grinding program of the crankshaft grinding machine is started, the robot places the long shaft of the crankshaft onto the V-block of the crankshaft grinding machine for positioning, and the telescopic rod of the telescopic cylinder moves down according to the pre-set program.

[0062] (5) Use the pressure plate to lock the long shaft of the crankshaft, and move the centering rod up to the initial height position to avoid the centering module affecting the machining of the outer surface of the crank.

Claims

1. A device for aligning the crankshaft's crank axis relative to its major axis, mounted on a crankshaft grinding machine, the crankshaft grinding machine having a fixture, the fixture comprising a detachably connected V-block and a pressure plate, the major axis of the crankshaft being placed on the V-block and clamped by the pressure plate, characterized in that: The centering device includes: The centering module includes a centering rod and a centering block. The centering rod is vertically mounted on a crankshaft grinding machine so that when the crankshaft is placed on the V-block, the centering rod is positioned directly above the crankshaft crank, and its vertical and horizontal positions are adjustable. The centering block has a downward-facing relief groove in the center. A centering screw and a centering spring are connected to opposite sides of the relief groove at the bottom of the centering block. The length of the centering screw protruding from the bottom of the centering block is the same as the length of the centering spring protruding from the bottom of the centering block in its free state. The centering block is equipped with [missing information - likely related to the mounting points of the centering screw and centering spring]. The threaded holes on both sides are respectively matched with the threads of the centering screw and the centering spring. The centering screw and the centering spring are connected to the threaded holes by threads and the length of the centering screw and the centering spring exposed at the bottom of the centering block is adjusted. The centering block is fixed to the side of the centering rod near the bottom and facing the V-block on one side of the relief groove, so that when the crankshaft is placed on the V-block and the side of the centering rod near the centering block is tangent to the crankshaft crank, the relief groove of the centering block just covers the crankshaft balance block, and the centering screw and the centering spring are respectively located on the parting surface on both sides of the balance block. The calibration module includes a calibration block and a reference shaft. The calibration block is detachably mounted on the suspended end of the V-block. The diameter of the reference shaft is the same as the diameter of the crankshaft crank. The reference shaft is horizontally connected to the calibration block and extends from the end face of the calibration block away from the V-block. The end face of the reference shaft away from the V-block extends beyond the end face of the centering rod facing the V-block. When the crankshaft is placed on the V-block, the axis of the reference shaft is aligned with the axis of the long shaft.

2. A device for centering the crank throw axis of a crankshaft relative to the major axis axis according to claim 1, characterized in that: The crank grinding machine is equipped with a connecting seat, on which a telescopic cylinder is vertically fixed. The telescopic rod of the telescopic cylinder is vertically downward and moves up and down relative to the cylinder body. The centering rod is installed on the telescopic rod of the cylinder and moves up and down with the telescopic rod of the cylinder.

3. The device for centering the crankpin axis of a crankshaft relative to the major shaft axis of claim 1, wherein: The crank grinding machine is equipped with a positioning plate, on which a flat key is installed horizontally. The upper end of the centering rod passes through the flat key and slides along it. A left adjusting plate and a right adjusting plate are fixed on both sides of the centering rod on the positioning plate. Both the left and right adjusting plates are provided with threaded holes, and adjusting screws are connected to the threaded holes. The two adjusting screws are respectively placed on the two sides of the centering rod. The centering rod is adjusted left and right by turning the adjusting screws. After the position adjustment is completed, the adjusting screws on both sides are tightened to lock the centering rod.

4. The device for centering the crankpin axis of a crankshaft relative to the major shaft axis of claim 1, wherein: The correction block includes a connecting plate and a mounting plate. The connecting plate is C-shaped and is sandwiched from both sides onto the end face of the V-shaped block at one of its suspended ends. The mounting plate is integrally connected to the connecting plate and is located at the top center of the connecting plate. The mounting plate is provided with mounting holes, and the reference shaft is connected to the mounting holes.

5. A device for centering the crankpin axis of a crankshaft relative to the major axis axis according to claim 4, characterized in that: One end of the reference shaft is connected to a connecting shaft, which is detachably connected to the mounting hole, so that the reference shaft is exposed from the end face of the correction block away from the V-block.

6. The device for centering the crankpin axis of a crankshaft relative to the major shaft axis of claim 1, wherein: The centering screw is located on the side of the centering block closest to the centering rod.

7. A method of centering the crankpin axis of a crankshaft relative to the major axis axis of a centering device according to claim 1, characterized in that Includes the following steps: (1) Install the alignment block with the reference axis installed on the V block, adjust the position of the centering rod up and down and left and right so that the side of the centering rod close to the centering block is tangent to the reference axis, lock the left and right position of the centering rod, and remove the alignment block from the V block. (2) Move the centering rod upwards to the initial height position; (3) Determine the downward stroke of the centering rod so that when the centering rod moves from the initial height position to the final height position according to the downward stroke, the centering screws and centering springs on both sides of the centering block press on the parting surfaces on both sides of the balance block respectively, and the side of the centering rod is tangent to the outer circle of the crankshaft crank. (4) Place the long shaft of the crankshaft to be processed on the V-block, and move the centering rod from the initial height position to the final height position according to the downward stroke of the centering rod; (5) Use the pressure plate to lock the long shaft of the crankshaft and move the centering rod up to the initial height position.

8. The method of centering the crank throw axis with respect to the major axis axis of the crankshaft according to claim 7, characterized in that: If the size of the next crankshaft to be processed is the same as that of the previous crankshaft to be processed, the crankshaft to be processed is centered directly from step (3); if the size of the next crankshaft to be processed is different from that of the previous crankshaft to be processed, after the previous crankshaft to be processed is completed, a reference shaft with the same crankshaft size as the next crankshaft to be processed is selected, and the crankshaft to be processed is centered from step (1).

9. The alignment method for the device for aligning the crankshaft's crank axis relative to the major axis as described in claim 7, characterized in that: The specific steps for determining the downward stroke of the centering rod in step (3) are as follows: (3.1) Calculate the theoretical downward stroke of the centering rod based on the crankshaft crank position and eccentricity requirements; (3.2) Place the long shaft of the crankshaft to be processed on the V-block. According to the theoretical downward stroke of the centering rod, move the centering rod from the initial height position to the final height position. Lock the long shaft of the crankshaft with the pressure plate and move the centering rod back to the initial height position. (3.3) Perform trial grinding on a crank grinder. Based on the symmetry of the crank after grinding and the grinding quality, confirm whether the centering position meets the processing requirements. If it meets the requirements, no adjustment is needed. The downward stroke of the centering rod is the theoretical downward stroke of the centering rod. If it does not meet the requirements, continue to adjust the downward stroke of the centering rod until the trial grinding meets the requirements.

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