A machining method for brake jaw faces of a large inside fillet design brake caliper

Abstract

The application relates to a machining method for a large-internal-arc-designed brake jaw surface, which comprises the following steps: S1: according to the size of the brake jaw surface and the diameter of a large-arc milling cutter, a large-arc cutting path is drawn on a brake jaw model, a spindle rotating speed and a feeding speed are given, and a numerical control machining program is compiled; S2: a cutting simulation model of the large-arc milling cutter and the brake jaw surface is established; S3: a machining method that the brake jaw surface is machined first and then the root roundness of the large-arc jaw surface is machined is adopted; S4: the jaw surface cutting path is designed in a parallel mode to the large-arc surface; S5: a two-dimensional sketch representing the jaw surface cutting path is drawn on a brake jaw finished product model to simulate the cutting process; S6: the feeding speeds of three sections of a round arc, a round arc segment and a tool retracting are set; S7: according to a milling calculation formula and a spindle power parameter of a machine tool, the feeding speed of each subsection point is calculated; S8: an optimized numerical control machining program is compiled according to steps S5, S6 and S7; and S9: the machining beats before and after optimization are calculated to confirm the effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobile parts, and relates to a machining method for a brake caliper jaw surface with a large fillet. BACKGROUND

[0002] In the design process of brake calipers of automobile chassis parts, in order to meet the braking performance requirements of customers on the brake calipers, whether the braking force of the brake caliper and the rigidity of the jaw part of the caliper body can withstand the deformation generated by braking needs to be considered. The rigidity of the jaw part of the caliper body is determined by the wall thickness of the jaw part, the root fillet of the jaw surface, and the strength of the back part of the caliper. There are three specifications of R3, R4.5 and R6 for the size of the common fillet. In order to not increase the weight of the brake caliper while meeting the braking requirements, a large fillet design is usually adopted. With the increase of the fillet, the cutting torque increases in geometric multiples. However, the spindle power of the numerical control equipment is limited. When machining the jaw surface of the brake caliper with a large fillet, only a lower feed speed can be used for cutting to ensure that the required machining power is within the range that can be tolerated by the spindle. Otherwise, the inner fillet and the position of the arc will be seriously vibrated, which cannot meet the product requirements, and even the spindle will directly jump the hydraulic pressure due to the excessive cutting resistance, resulting in shutdown. The lower feed speed leads to a long processing cycle and low processing efficiency, which cannot meet the production requirements. SUMMARY

[0003] Therefore, the purpose of the application is to provide a machining method for the jaw surface of a brake caliper with a large fillet, which can improve the machining efficiency of large arc machining and ensure the consistency of the product.

[0004] To achieve the above purpose, the application provides the following technical scheme:

[0005] A machining method for the jaw surface of a brake caliper with a large fillet, comprising the following steps:

[0006] S1: According to the size of the jaw surface of the brake caliper and the diameter of the large arc milling cutter, a large arc cutting path is drawn on the brake caliper model. At the same time, the spindle speed and the feed speed are given according to the past experience, and the numerical control machining program of the jaw surface of the brake caliper is compiled;

[0007] S2: A cutting simulation model of the large arc milling cutter and the jaw surface of the brake caliper is established to simulate the relative position relationship between the large arc milling cutter and the jaw surface of the brake caliper at the lowest point of the feed speed;

[0008] S3: A machining method of first machining the jaw surface of the brake caliper and then machining the root fillet of the large arc jaw surface is adopted;

[0009] S4: The cutting path of the jaw surface is designed in parallel to the large arc surface;

[0010] S5: Draw a two-dimensional sketch on the brake caliper finished model to represent the claw surface cutting path, and then draw a circle with the same diameter as the tool on the cutting path to simulate a large arc milling cutter, and slowly drag the center of the circle to simulate the cutting process;

[0011] S6: According to the large arc cutting path, set the arc front, arc segment, and tool retracting 3 segment feed speed;

[0012] S7: According to the milling calculation formula and the spindle power parameters of the machine tool, the feed speed of each segment point on the claw surface cutting path and the large arc cutting path is calculated;

[0013] S8: According to steps S5, S6, S7, the optimized numerical control machining program of the brake caliper claw surface is compiled;

[0014] S9: Calculate the machining cycle before and after optimization respectively, and confirm the improvement effect.

[0015] Further, in step S4, the large arc radial allowance is designed as the blank allowance, and a claw wall thickness allowance of 0.05-0.1mm is also reserved.

[0016] Further, in step S5, the change of the radial cutting width is observed, and the points with significant change of the radial cutting width are taken as the segment points of the numerical control program, and the segment point coordinate values and the radial cutting width are recorded.

[0017] Further, according to the different radial cutting widths during the machining of the claw surface and the large arc, different feed speeds are calculated and given.

[0018] The beneficial effects of the present application are:

[0019] The present application fundamentally reduces the cutting force by separating the machining method of the brake caliper claw surface and the large arc root R, ensures that the cutting allowance is basically consistent during final machining, has small stress fluctuation, and has good consistency of the machined large arc surface. At the same time, combined with the change of the radial cutting width during the machining of the caliper body claw surface, the cutting path is divided into multiple segments, and different feed speeds are given separately, so that the performance of the machine tool is fully utilized. By using this method, the entire cutting cycle can be reduced by more than 10%.

[0020] Other advantages, objects, and features of the present application will be set forth in part in the following specification, and in part will become apparent to those skilled in the art from the examination of the following specification, or can be learned from practice of the present application. The objects and other advantages of the present application can be realized and attained by the methods and instrumentalities set forth in the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to make the objects, technical solutions and advantages of the present application clearer, the preferred embodiments of the present application will be described in detail below with reference to the drawings, in which:

[0022] Figure 1 Structure diagram of the brake caliper

[0023] Figure 2 Initial cutting path diagram

[0024] Figure 3 NC program of the initial cutting path

[0025] Figure 4 Relative position of the machining part cutting site and the tool under the lowest feeding speed point of the initial cutting path

[0026] Figure 5 Claw surface cutting path in the present application

[0027] Figure 6 Claw surface and large circular arc radial cutting width diagram in the present application

[0028] Figure 7 Claw surface segmented point X, Y coordinates and corresponding cutting width in the present application

[0029] Figure 8 Optimized example program before optimization in the present application

[0030] Figure 9 Optimized example program after optimization in the present application

[0031] Reference signs:

[0032] 1, brake caliper; 101, brake caliper claw surface; 102, inner fillet; 1021, claw surface root fillet; 103, large circular arc surface; 2, large circular arc milling cutter; 401, claw surface cutting path starting point; 402, claw surface cutting path ending point; 5, large circular arc cutting path; 6, large circular arc radial allowance; 7, radial cutting width DETAILED DESCRIPTION

[0033] The present application will be described in greater detail by way of specific embodiments, from which its advantages and objects will become apparent.

[0034] The drawings are only used for exemplary illustration, and the representation is only a schematic diagram, and cannot be understood as a limitation on the present application; in order to better illustrate the embodiments of the present application, some components of the drawings are omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings can be omitted.

[0035] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it should be understood that if the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back" and the like are based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0036] Please refer to Figures 1-9 , a large inner fillet design brake jaw face machining method, comprising the following steps:

[0037] First, according to the size of the brake jaw face 101 and the diameter of the large arc milling cutter 2, draw the large arc cutting path 5 on the brake jaw 1 model, at the same time, according to experience, give the spindle speed and the feed speed, compile the numerical control machining program of the brake jaw face 101, such as Figure 1 , 2 , 3, the brake jaw 1 with inner fillet 102;

[0038] Second, establish the cutting simulation model of the large arc milling cutter 2 and the brake jaw face 101, simulate the relative position relationship of the large arc milling cutter 2 and the brake jaw face 101 at the lowest point of the feed speed, such as Figure 4 ;

[0039] Third, according to the characteristics that the large arc surface 103 of the brake jaw face 101 and the root round corner 1021 of the jaw face of the large arc participate in cutting at the same time at the lowest point of the feed speed, adopt the machining method of machining the large arc surface 103 of the brake jaw face 101 first, and then machining the root round corner 1021 of the jaw face of the large arc;

[0040] Fourth, the jaw face cutting path is designed in parallel to the large arc surface 103, leaving a large arc radial allowance 6 as a blank design allowance, and at the same time leaving a jaw wall thickness allowance of 0.05-0.1mm, such as Figure 5 , one side is the starting point 401 of the jaw face cutting path, and the other side is the end point 402 of the jaw face cutting path;

[0041] Fifth, draw a two-dimensional sketch on the finished model of brake caliper 1 to represent the jaw face cutting path. Then, draw a circle with the same diameter as the tool on the jaw face cutting path to simulate a large circular arc end mill 2. Slowly drag the center of the circle to simulate the cutting process and observe the change in the radial cutting width 7. Figure 6 Simultaneously, points where the radial cutting width 7 changes significantly are used as segmentation points in the CNC program, and the coordinates of these segmentation points and the radial cutting width 7 are recorded. Figure 7 This is so that the feed rate can be calculated;

[0042] Step 6: Based on the large arc cutting path 5, and considering the cutting conditions where the jaw face allowance is only 0.05-0.1 and the large arc root allowance is consistent, it is only necessary to set the feed speed for the arc front, the arc segment, and the retraction three segments.

[0043] Step 7: Based on the milling calculation formula and the machine tool spindle power parameters, calculate the feed rate at each segment point on each jaw face cutting path and the large circle arc cutting path 5.

[0044]

[0045] Where P mot Main spindle power, Q is metal removal rate, k c Unit cutting force (N / mm) 2 ), where η is the machine tool efficiency coefficient (0.7-0.9), a p Depth of cut, unit (mm), a e Radial cutting width 7, unit (mm), v f Feed rate, in m / min, where n is the rotational speed in rpm;

[0046] Step 8: Based on steps 5, 6, and 7, compile the optimized CNC machining program for the brake caliper jaw 1, as follows: Figure 8 , 9 ;

[0047] The ninth step is to calculate the processing cycle time before and after optimization to confirm the improvement effect.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for machining the claw surface of a brake caliper with a large inner radius, characterized in that, Includes the following steps: S1: Based on the dimensions of the brake caliper jaws (101) and the diameter of the large circular arc milling cutter (2), draw the large circular arc cutting path (5) on the brake caliper (1) model, give the spindle speed and feed rate, and compile the CNC machining program for the brake caliper jaws (101); S2: Establish a cutting simulation model of the large circular arc end mill (2) and the brake caliper jaws (101) to simulate the relative positional relationship between the large circular arc end mill (201) and the brake caliper jaws (101) at the lowest feed rate. S3: The machining method is to first machine the large arc surface (103) of the brake caliper claw surface (101), and then machine the radius (1021) at the root of the large arc claw surface. S4: The claw surface cutting path is designed to be parallel to the large arc surface (103), leaving a radial allowance (6) for the blank design, and leaving a claw wall thickness allowance of 0.05 to 0.1 mm. S5: Draw a two-dimensional sketch on the finished model of the brake caliper (1) to represent the cutting path of the claw face. Then draw a circle with the same diameter as the tool to simulate the large arc milling cutter (2) on the cutting path. Slowly drag the center of the circle to simulate the cutting process and observe the change of the radial cutting width (7). At the same time, take the point where the radial cutting width (7) changes significantly as the segment point of the CNC program, record the coordinate value of the segment point and the radial cutting width (7). Calculate and give different feed rates according to the different radial cutting widths (7) when machining the claw face and the large arc. S6: Based on the large circular arc cutting path (5), set the feed speeds for the arc before, the arc segment, and the retraction three segments; S7: Based on the milling calculation formula and the machine tool spindle power parameters, calculate the feed rate of each segment point on each claw face cutting path and large circle arc cutting path (5); S8: Compile the optimized CNC machining program for the brake caliper claw surface (101) based on steps S5, S6, and S7; S9: Calculate the processing cycle time before and after optimization to confirm the improvement effect.

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