A crankshaft machining tool based on a follow-up grinding machine

Abstract

The application discloses a kind of based on servo grinding machine tool's crankshaft processing frock, the upper elastic support of this processing frock has centering rod;Self-positioning chicken heart chuck is radially connected to centering rod, and the other end of the self-positioning chicken heart chuck is circumferentially limited and is installed on the outside of crankshaft, to transmit the circumferential rotation force of spindle drive head to crankshaft on.The frock is fixed by self-positioning chicken heart chuck on the circumferential rotation of spindle drive head crankshaft, avoid relative rotation between crankshaft and spindle drive head in the process of processing, i.e. avoid crankshaft idling, always guarantee the basic plane of spindle drive head, the alignment plane of counterweight top is coplanar, guarantee the phase angle accuracy of crankshaft and spindle drive head in the process of rotation, to improve the processing efficiency, while guarantee the batch processing precision of crankshaft.

Description

Technical Field

[0001] This invention relates to the field of tooling and fixture technology, specifically to a crankshaft machining tool based on a follower grinding machine. Background Technology

[0002] Currently, with the increasing demand for robots driving the continuous development of robot technology, the precision requirements for robot reducers are also constantly increasing. Traditional equipment for machining crankshafts consists of a "common cylindrical grinder + eccentric fixture," where the machining method involves positioning and clamping the crankshaft using its involute spline, and machining by aligning the high points of the two crankshafts. This machining method suffers from poor rigidity, poor workpiece consistency, poor versatility, significant grinding wheel waste, complex tooling, inaccurate phase difference between the two eccentric wheels, and low production efficiency. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, one objective of this invention is to propose a crankshaft machining fixture based on a follow-up grinding machine tool. This fixture can machine different models of crankshafts by changing the self-positioning chuck, exhibiting good versatility. Furthermore, for mass-produced crankshafts, batch processing can be achieved by aligning the high points and phase angles of two crankshafts in a single step, improving workpiece consistency and production efficiency, significantly increasing the product qualification rate, thereby reducing assembly errors in RV reducers, ensuring manufacturing precision, and meeting the high-precision requirements of robot RV reducers. By setting the positioning point of the self-positioning chuck inside the fixture, interference between the grinding wheel and the fixture is reduced, increasing the effective machining diameter of the grinding wheel, saving grinding wheels, and reducing costs.

[0004] Therefore, the present invention provides a crankshaft machining fixture based on a follower grinding machine tool. One end of the crankshaft positioned by the machining fixture is axially pressed by a front center coaxially fixed on the spindle drive head, and the other end of the crankshaft is axially pressed by a rear center on the machine tool. The lower part of the machining fixture is fixed on the axial end face of the spindle drive head, the middle part of the machining fixture is coaxially sleeved on the outside of the front center, and the upper part of the machining fixture is elastically supported by a centering rod. A self-positioning chuck is radially engaged on the centering rod, and the other end of the self-positioning chuck is circumferentially limited and sleeved on the outside of the crankshaft to transmit the circumferential rotational force of the spindle drive head to the crankshaft.

[0005] Preferably, the machining fixture includes crescent-shaped pads, elastic rings, and centering blocks. Multiple crescent-shaped pads are provided and axially stacked and fixed on the axial end face of the spindle drive head, and elastic rings are clamped and fixed between the multiple crescent-shaped pads. Multiple elastic rings are provided at intervals, and centering blocks are fixedly connected between the elastic rings. Centering rods are fixedly inserted into the centering blocks in the radial direction relative to the front tip.

[0006] Preferably, the self-positioning chuck has an L-shaped structure. One end of the self-positioning chuck has a V-shaped groove for radially engaging the centering rod, and the other end of the self-positioning chuck has a spline sleeve integrally formed for circumferentially limiting and sleeved on the outside of the crankshaft. The spline sleeve has a threaded hole radially opened, and a bolt connected by the threaded hole radially tightens the crankshaft to fix the self-positioning chuck on the crankshaft.

[0007] Preferably, a plurality of screws are axially fixed to the upper part of the elastic ring, the middle part of the screws penetrates and fixes the centering block, and the other end of the screws is threaded to the fastening back plate. The screws and the fastening back plate provide axial clamping force to axially clamp the centering block between the plurality of elastic rings.

[0008] Preferably, a semi-circular steel plate is bolted to one axial end face of the lower part of the elastic ring plate. The bolt on the semi-circular steel plate passes through multiple crescent-shaped pads and the elastic ring plate in sequence and is threaded to the axial end face of the main shaft drive head.

[0009] Preferably, a foundation finding plane is radially formed on the circumferential outer wall of the spindle drive head; a centering rod is radially inserted into the center of the top plane of the centering block, and the top plane of the centering block is flush with the foundation finding plane.

[0010] The advantages of this invention compared to the prior art are:

[0011] (1) The workpiece in this invention is positioned by the front and rear double centers of the grinding machine, which has good versatility, low cost, good rigidity, high repeatability, and facilitates loading and unloading of workpieces.

[0012] (2) The perpendicularity between the centering block and the centering rod in the centering block of the present invention is less than or equal to 0.002. When the workpiece is installed, the phase angle of the spline and the eccentric circle is consistent, which is good and versatile, which is conducive to improving the assembly accuracy and thus improving the product accuracy. The good consistency of the phase angle of the spline and the eccentric circle can reserve a small finishing allowance and improve work efficiency.

[0013] (3) The elastic ring structure in this invention is simple, easy to manufacture, and the elastic bearing force is adjustable. It is suitable for different workpieces of different sizes, with low cost and good versatility.

[0014] (4) The V-groove of the self-positioning chuck in this invention is in contact with the centering rod on the centering block, which can realize quick workpiece replacement, self-centering, and self-alignment; the elastic ring applies axial force to it in the axial direction, so that the two are firmly connected and the positional relationship between the part and the tooling is guaranteed, ensuring the repeatability of the workpiece clamping accuracy, making workpiece alignment convenient and simple, and batch processing can be achieved in one alignment; the self-positioning chuck is designed to reduce the radial dimension, thereby increasing the usable size of the grinding wheel by half, reducing the frequency of grinding wheel replacement, and saving costs.

[0015] This invention is applicable to small-batch or large-batch machining of various precision external diameters and eccentric circles. It has a wide range of applications and high efficiency. By changing the self-positioning chuck, it can machine different models of crankshafts, demonstrating good versatility. Furthermore, for batch production workpieces, multiple machining operations can be performed with a single alignment, improving production efficiency and increasing product yield and quality. This invention also features a simple machining fixture structure, low cost, strong versatility, and high product consistency and yield, making it a promising technology with broad application prospects. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is an exploded three-dimensional view of the structure of the present invention;

[0018] Figure 2 This is a partial cross-sectional view of the three-dimensional structure of the present invention;

[0019] Figure 3 This is a three-dimensional structural diagram of the self-positioning heart-shaped clip in this invention;

[0020] Figure 4 This is a three-dimensional structural diagram of the elastic ring plate in this invention;

[0021] Figure 5 This is a three-dimensional structural diagram of the centering rod in this invention;

[0022] Figure 6 This is a three-dimensional structural diagram of the counterweight in this invention;

[0023] In the diagram: 1-Spindle drive head; 2-Fastening back plate; 3-Elastic ring; 4-Centering rod; 5-Centering block; 7-Screw; 8-Self-positioning chuck; 9-Crankshaft; 10-Rear center; 11-Semi-circular steel sheet; 12-Crescent pad; 13-Front center; 14-V-groove; 15-Spline sleeve; 16-Threaded hole. Detailed Implementation

[0024] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0025] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] The present invention discloses a crankshaft machining fixture based on a follower grinding machine tool. One end of the crankshaft 9 positioned by the machining fixture is axially pressed by a front center 13 coaxially fixed on the spindle drive head 1, and the other end of the crankshaft is axially pressed by a rear center 10 on the machine tool. The lower part of the machining fixture is fixed on the axial end face of the spindle drive head, the middle part of the machining fixture is coaxially sleeved outside the front center, and the upper part of the machining fixture is elastically supported by a centering rod 4. A self-positioning chuck 8 is radially engaged on the centering rod, and the other end of the self-positioning chuck 8 is circumferentially limited and sleeved outside the crankshaft to transmit the circumferential rotational force of the spindle drive head to the crankshaft.

[0028] Preferably, the machining fixture includes a crescent-shaped pad 12, an elastic ring 3, and a centering block 5. Multiple crescent-shaped pads are provided and are axially stacked and fixed on the axial end face of the spindle drive head, and elastic rings are clamped and fixed between the multiple crescent-shaped pads. Multiple elastic rings are provided at intervals, and the centering block is fixedly connected between the elastic rings. A centering rod is fixedly inserted into the centering block in the radial direction relative to the front tip.

[0029] Preferably, the self-positioning chuck has an L-shaped structure. One end of the self-positioning chuck has a V-groove 14 for radially engaging the centering rod, and the other end of the self-positioning chuck has a spline sleeve 15 integrally formed for circumferentially limiting and sleeved on the outside of the crankshaft. The spline sleeve has a threaded hole 16 radially formed, and a bolt connected by the threaded hole radially tightens the crankshaft to fix the self-positioning chuck on the crankshaft.

[0030] Preferably, a plurality of screws 7 are axially fixed to the upper part of the elastic ring plate, the middle part of the screw is fixed to the centering block, and the other end of the screw is threaded to the fastening back plate 2. The screw and the fastening back plate provide axial clamping force to axially clamp the centering block between the plurality of elastic ring plates.

[0031] Preferably, a semi-circular steel plate 11 is bolted to one axial end face of the lower part of the elastic ring plate. The bolt on the semi-circular steel plate passes through multiple crescent-shaped pads and the elastic ring plate in sequence and is threaded to the axial end face of the main shaft drive head.

[0032] Preferably, a foundation finding plane is radially formed on the circumferential outer wall of the spindle drive head; a centering rod is radially inserted into the center of the top plane of the centering block, and the top plane of the centering block is flush with the foundation finding plane.

[0033] To more clearly illustrate the specific embodiments of the present invention, an example is provided below:

[0034] This invention discloses a crankshaft machining fixture based on a follower grinding machine, mainly comprising a centering block, a centering rod, an elastic ring plate, a self-positioning chuck, a crescent-shaped pad, a semi-circular steel sheet, and a fastening back plate. The assembly structure of this fixture consists of... Figure 1 and Figure 2 As shown.

[0035] (1) Middle block

[0036] Figure 6 This is a schematic diagram of a centering block. The centering block is used to align the relative positional relationship between the fixture and the workpiece, i.e., the phase angle between the workpiece spline and the eccentric circle. The alignment plane is perpendicular to the pin hole, with a perpendicularity of less than or equal to 0.002. The centering block is installed between two elastic rings through two holes on it.

[0037] (2) For the middle rod

[0038] Figure 5 This is a schematic diagram of the centering rod. The centering rod is used to drive the self-positioning chuck head to rotate, and it functions as a lever for positioning and transmission. The centering rod is a tapered mandrel, which is installed in the pin hole on the centering block.

[0039] (3) Elastic ring

[0040] Figure 4 This is a schematic diagram of an elastic ring, which provides rotational motion and axial pressure Fz to the self-positioning chuck. During operation, the elastic ring generates axial pressure through its own deformation. There are two elastic rings used together; they connect to the spindle headstock via three holes at the bottom, along with two crescent-shaped pads and a semi-circular steel plate. The two holes at the top connect to the fastening back plate and the centering block, transmitting the rotational motion of the spindle headstock to the centering rod, and then to the self-positioning chuck, thus moving the workpiece.

[0041] (4) Self-positioning heart-shaped clip

[0042] Figure 3 The self-positioning chuck is designed to determine the circumferential positional relationship between the tooling and the workpiece, and to transmit the rotational motion of the headstock to the workpiece, causing the workpiece to rotate together. The internal spline of the self-positioning chuck is connected to the external spline of the workpiece, and the V-groove on the chuck is in contact with the centering bar on the centering block. It is pressed by the axial pressure provided by the two elastic ring plates, which ensures circumferential and axial positioning.

[0043] The working principle of this invention is as follows:

[0044] (1) Install the spindle drive head and the front center on the headstock of the grinding machine, and the rear center on the tailstock of the machine tool. Adjust the positions of the front and rear centers so that the center hole of the workpiece is firmly engaged with the two centers, and lock the front and rear centers.

[0045] (2) Press the crescent-shaped pad, the semi-circular steel sheet, and the two elastic rings together. Figure 1 The tooling structure is intended to be mounted on the spindle drive headstock by screws.

[0046] (3) Similarly, fasten the back plate, centering rod, and centering block according to... Figure 1 Alternatively, the tooling structure is intended to be mounted on two elastic rings by screws.

[0047] (4) Install the self-positioning chuck and the workpiece through the spline on the workpiece, and fix the chuck with fastening screws to prevent it from moving axially with the workpiece; it is emphasized that the positioning point of the chuck should be aligned with the positioning point of the spline to ensure the phase angle form and position error of the chuck and the eccentric circle.

[0048] (5) Make the V-groove on the self-positioning heart-shaped card head contact and engage with the centering rod on the centering block to ensure that the deformation of the elastic ring can provide sufficient axial clamping force.

[0049] (6) Use a lever dial indicator to find the center block to find the front side. The error is less than or equal to 0.002. At this time, the highest point of the workpiece eccentric circle is the grinding wheel tool setting point. Operate the machine tool to set this point as the C-axis zero point, which completes the tool setting and installation steps before workpiece processing.

[0050] (7) If you need to replace the workpiece with the same drawing, you only need to remove the heart-shaped chuck and the workpiece and replace it with a new workpiece. There is no need to repeat the previous alignment process, so you can quickly replace the workpiece.

[0051] (8) If it is necessary to change the workpiece to a different drawing size, it is only necessary to remake a new heart-shaped chuck and adjust the position of the front and rear tips to achieve quick workpiece replacement, saving a lot of time and improving processing efficiency.

[0052] This invention discloses a crankshaft machining fixture based on a follower grinding machine tool. The crankshaft is axially clamped and positioned by the machine tool's built-in front and rear centers. The crankshaft is circumferentially fixed by a self-positioning chuck on the spindle drive head, preventing relative rotation between the crankshaft and the spindle drive head during machining, thus avoiding free rotation of the crankshaft. This ensures that the base plane of the spindle drive head and the alignment plane of the top of the counterweight are always coplanar, guaranteeing the phase angle accuracy of the crankshaft and the spindle drive head during rotation. This improves machining efficiency while ensuring the batch machining accuracy of the crankshaft.

[0053] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A crankshaft machining fixture based on a follower grinding machine tool, wherein one end of the crankshaft positioned by the machining fixture is axially pressed by a front center coaxially fixed on the spindle drive head, and the other end of the crankshaft is axially pressed by a rear center on the machine tool, characterized in that: The lower part of the machining tool is fixed on the axial end surface of the spindle driving head, the middle part of the machining tool is coaxially sleeved outside the front center, and the upper part of the machining tool elastically supports the centering rod; the self-positioning centering chuck is radially clamped on the centering rod, the other end of the self-positioning centering chuck is circumferentially limited and sleeved outside the crankshaft, so that the circumferential rotation force of the spindle driving head is transmitted to the crankshaft; the machining tool comprises a centering block, the centering block is fixedly inserted with the centering rod in the radial direction relative to the front center; the self-positioning centering chuck is of L-shaped structure, a V-shaped groove for clamping the centering rod is formed at one end of the self-positioning centering chuck, and a spline sleeve for circumferentially limiting and sleeving outside the crankshaft is integrally formed at the other end of the self-positioning centering chuck; the centering block is aligned by using a lever dial gauge, and at this time, the highest point of the eccentric circle of the workpiece is the grinding wheel alignment point.

2. The crankshaft machining tooling apparatus based on a follow-up grinding machine according to claim 1, characterized in that: The machining tool further comprises crescent pads and elastic ring pieces; the crescent pads are provided with a plurality of axial stacking and fixed on the axial end surface of the spindle driving head, and the elastic ring pieces are clamped and fixed between the plurality of crescent pads; the elastic ring pieces are spaced apart and provided with a plurality of elastic ring pieces, and the elastic ring pieces are fixedly connected with the centering block.

3. The crankshaft machining tooling apparatus based on a follow-up grinding machine according to claim 1, characterized in that: A threaded hole is radially formed in the spline sleeve, a bolt threadedly connected in the threaded hole radially abuts against the crankshaft to fix the self-positioning centering chuck on the crankshaft.

4. The crankshaft machining tooling apparatus based on a follow-up grinding machine according to claim 2, characterized in that: A plurality of screws are axially and fixedly provided in the upper part of the elastic ring piece, the middle part of the screw penetrates and fixes the centering block, and the other end of the screw is threadedly connected with the fastening back plate, so that the axial clamping force provided by the screw and the fastening back plate axially clamps the centering block between the plurality of elastic ring pieces.

5. The crankshaft machining tooling apparatus based on a follow-up grinding machine according to claim 2, characterized in that: A semicircular steel sheet is bolted and connected on one axial end surface of the lower part of the elastic ring piece, the bolt on the semicircular steel sheet penetrates the plurality of crescent pads and the elastic ring piece in sequence and is threadedly connected with the axial end surface of the spindle driving head.

6. The crankshaft machining tooling apparatus based on a follow-up grinding machine according to claim 2, characterized in that: A foundation alignment surface is radially formed in the circumferential outer wall of the spindle driving head; the top surface of the centering block is radially inserted with the centering rod, and the top surface of the centering block is flush with the foundation alignment surface.

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