A CBN grinding wheel segment inner arc dressing device and method

Abstract

The present invention discloses a device and method for dressing the inner arc of a CBN grinding wheel segment. The device adopts a swing-arm motion mode and can dress the inner arcs of CBN and diamond grinding wheel segments of different specifications. The dressing device replaces traditional circular arc interpolation with a fixed-axis swing mode and uses circular arc guide rails as auxiliary supports to complete the swinging action, which greatly simplifies the inner arc dressing action, reduces the risk of lead screw wear in the traditional circular arc interpolation dressing process, and improves the dressing efficiency and precision of the inner arc of the grinding wheel segment.

Description

Technical Field

[0001] The invention belongs to the technical field of superhard material grinding wheel dressing, and in particular relates to a CBN grinding wheel segment inner arc dressing device and method. Background Art

[0002] With the emergence of some difficult-to-machine materials, the requirements for modern grinding technology are becoming increasingly higher. Silicon carbide and ordinary corundum abrasive grinding wheels can no longer fully meet the grinding requirements. CBN grinding wheels are widely used in high-precision fields such as aerospace, automobiles, semiconductors, and high-hardness industrial basic parts processing of bearings and gears due to their excellent grinding performance such as good sharpness, high linear speed, strong wear resistance, high grinding efficiency, and low burn resistance. They have become an indispensable processing tool in modern grinding.

[0003] For CBN grinding wheels, more than 90% of CBN grinding wheel products with a diameter greater than 200mm are segmented bonded grinding wheels during the manufacturing process. During the manufacturing process, the mixed abrasive is pressed into a certain number of grinding wheel segments under a certain pressure through a forming mold. After sintering, the grinding wheel segments are bonded to the substrate one by one, and finally the abrasive layer of the finished grinding wheel is finely trimmed.

[0004] like Figure 1 As shown in the figure, the CBN grinding wheel consists of grinding wheel segments and a grinding wheel base. The grinding wheel segments are arranged along the outer circle of the grinding wheel base, and the inner arc of the grinding wheel segments is bonded to the outer circle of the base with strong adhesive. Therefore, the matching accuracy of the inner arc surface of the grinding wheel segments and the outer circle of the base has a great influence on the bonding strength.

[0005] After high temperature sintering, the inner arc surface of the grinding wheel segment will undergo irregular and irregular deformation. The four corners of the deformed segment are obviously warped and the thickness is uneven. Figure 2 and Figure 3 As shown in the figure, if the segments are bonded directly to the outer diameter of the substrate, they will be squeezed and deformed, and unevenly stressed. This not only affects the bonding strength, but also increases the risk of the segments falling off during grinding. Therefore, to ensure the bonding strength between the grinding wheel segments and the substrate, the inner arc of each grinding wheel segment needs to be trimmed before bonding to ensure that the outer diameter of the substrate and the inner diameter of the grinding wheel segment are well matched.

[0006] Currently, the most commonly used method for inner arc dressing is to use a diamond grinding wheel to perform layered circular interpolation dressing on the grinding wheel segments. This circular interpolation dressing process usually requires three-axis linkage and has high requirements for CNC equipment. In addition, due to the spindle structure and power limitations of the machine tool, only small tools, high speeds, and fast feeds can be used for processing. The number of cycle passes is large, and to prevent heat and excessive wear of the tool grinding wheel, water cooling is used for processing. After the inner arc dressing of the segment is completed, the segment needs to be cleaned and dried for a long time. The overall process time is long and the processing efficiency is low. Secondly, the essence of circular interpolation is to divide the arc into several straight line segments for linear interpolation, which affects the dressing accuracy of the inner arc of the segment. Summary of the Invention

[0007] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and provide a CBN grinding wheel segment inner arc dressing device and method, so as to achieve the dressing of the inner arcs of grinding wheel segments of different specifications and improve the dressing accuracy of the inner arcs of grinding wheel segments.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A CBN grinding wheel segment inner arc dressing device comprises a base, a linear guide rail, a slide slidably arranged on the linear guide rail, and a swing control system and a movement control system arranged accordingly;

[0010] A rotatable support plate is further provided between the base and the linear guide rail, the linear guide rail is fixed on the support plate, and an arc guide rail is further provided on the lower end surface of the support plate, and the bottom limit of the arc guide rail is fixed on the base;

[0011] The right end of the support plate rotates with the rotary shaft fixed on the base and moves along the arc guide rail under the action of the swing control system; the slide slides left and right along the linear guide rail under the control of the movement control system;

[0012] During assembly, the grinding wheel segment is fixed on the slide, and the center line of the grinding wheel segment is collinear with the center line of the tool grinding wheel and the center line of the rotary axis.

[0013] The swing control system includes a swing drive motor and a gear transmission pair, and the swing drive motor is connected to the gear transmission pair through a reducer, and the driven gear of the gear transmission pair is fixed on the support plate and its center line is also collinear with the center line of the rotating shaft.

[0014] The gear transmission pair also includes a driving gear meshing with the driven gear for transmission, and the driving gear is transmission-connected to the reducer.

[0015] The mobile control system includes a mobile servo motor and a screw transmission pair, and the mobile servo motor is connected to the screw transmission pair through a coupling and drives the slide to move, and the screw transmission pair is arranged along a linear track, and the mobile servo motor is fixed on the support plate through a motor base.

[0016] The slide is provided with a plurality of mounting holes for mounting grinding wheel segments.

[0017] A method for trimming the inner arc of a CBN grinding wheel segment comprises the following steps:

[0018] (1) Select a diamond grinding wheel as the tool grinding wheel and install it on the tool grinding wheel spindle through a standard tool holder;

[0019] (2) Adjust the yaw angle of the support plate. The swing drive motor drives the gear transmission pair to rotate and drive the support plate to swing around the rotation axis so that the absolute yaw angle of the support plate is 0°;

[0020] (3) Installing the grinding wheel segment on the slide, and controlling the slide to move by the motion control system, setting the position where the grinding wheel segment contacts the tool grinding wheel as the initial dressing position;

[0021] (4) Input the yaw angle;

[0022] (5) Set the constant swing speed N of the grinding wheel segment and calculate the speed F of the tool grinding wheel feeding in the vertical Z direction;

[0023] (6) Set the number of cycles and the amount of single feed, and then start the machine tool;

[0024] (7) Inspect the inner arc surface of the grinding wheel segment after trimming.

[0025] The yaw angle in step (4) is calculated as follows:

[0026] Let the inner arc center of the grinding wheel segment be O, the straight line CC' be the chord length L, the arc length corresponding to the chord length be P, the angle corresponding to the chord length be θ, and the inner arc radius of the grinding wheel segment be R1, then:

[0027] P=R1θ

[0028] L=2R1sin(θ / 2)

[0029] Therefore,

[0030]

[0031] In order to ensure that the inner arc of the grinding wheel segment is completely ground, the swing angle reserve Δθ needs to be increased when using the swing arm to grind the arc. Therefore, the swing angle is:

[0032]

[0033] The value of Δθ is 2-4°.

[0034] The speed F of the tool grinding wheel feeding in the vertical Z direction in step (5) satisfies the following conditions:

[0035] Let the constant swing speed of the grinding wheel segment be N, the chord length of the grinding wheel segment be L, the inner arc radius be R1, the tool thickness of the tool grinding wheel be D, the distance the tool grinding wheel moves corresponding to one swing of the grinding wheel segment is H, and the angle corresponding to the chord length L is:

[0036]

[0037] The time required to rotate the angle θ' is:

[0038] To ensure that the inner arc surface is completely trimmed, F·t=H≤D must be satisfied;

[0039] That is, the speed at which the upper wheel of the tool moves up and down should meet the following requirements:

[0040]

[0041] The beneficial effects of the present invention are:

[0042] (1) The CBN grinding wheel segment inner arc dressing device and method adopt a swing arm motion mode, which can be used to dress the inner arcs of CBN and diamond grinding wheel segments of different specifications. The dressing device replaces the traditional circular arc interpolation with a fixed axis swing, and uses an arc guide rail as an auxiliary support to complete the swinging action, which greatly simplifies the inner arc dressing action, reduces the risk of screw wear in the traditional circular arc interpolation dressing process, and improves the dressing accuracy of the inner arc of the grinding wheel segment.

[0043] (2) The support plate of the trimming device uses a gear transmission pair as the power source for swinging, and connects the driven gear to the support plate to complete the swinging action of the workbench. The structure is compact and the transmission is smooth. The swing angle of the support plate can be set by the numerical control device to complete the trimming of segments with different chord length specifications, and the trimming of segments with different inner diameter specifications can be completed by controlling the position of the slide.

[0044] (3) The machine tool equipped with the workbench can use a tool grinding wheel of a certain thickness and adopt a slow feed method with a large cutting depth to increase the contact area of ​​the tool grinding wheel on the segment, thereby simplifying and shortening the processing path of the inner arc surface of the segment, and significantly improving the dressing efficiency.

[0045] (4) Through this swing-arm inner arc trimming process, the inner arcs of segments of different specifications can be trimmed using a tool grinding wheel, and the X-axis can be compensated by the CNC system after the tool grinding wheel is worn. The operation is simple, convenient and fast; all components are assembled in a connected manner, without the need for special casting, simple to manufacture and low in cost.

[0046] (5) When the inner arc of the segment is trimmed by the dressing device, the workbench drives the segment to swing at a corresponding angle, and the tool grinding wheel rotates while moving up and down. Therefore, the movement trajectory of the tool grinding wheel is a cross Z-shaped spiral line. The influence of the tool mark on the inner arc surface can be reduced by controlling the swing speed of the grinding wheel segment and the speed of the tool grinding wheel moving up and down, thereby effectively improving the trimming accuracy of the inner arc.

[0047] (6) The dressing device has a simple and compact structure and can be used with vertical grinders and vertical milling machines, with strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the grinding wheel structure;

[0049] Figure 2 It is the shape of the grinding wheel segment before sintering;

[0050] Figure 3 It is the shape of the grinding wheel segment after sintering;

[0051] Figure 4 It is a structural schematic diagram of the present invention;

[0052] Figure 5 yes Figure 4 A partial enlarged schematic diagram;

[0053] Figure 6 is a top view of the present invention;

[0054] Figure 7 is a trimming path diagram of the present invention;

[0055] Figure 8 It is a schematic diagram of the structural model of the grinding wheel segment;

[0056] Figure 9 is a schematic diagram of the trimming trajectory; DETAILED DESCRIPTION

[0057] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0058] See also Figure 1. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0059] The present invention provides a CBN grinding wheel segment inner arc dressing device and method, such as Figures 4 to 9 shown.

[0060] A CBN grinding wheel segment inner arc dressing device includes a base 5, a linear guide 11, a slide 15 sliding on the linear guide 11, and a corresponding swing control system and a movement control system; a support plate 6 is rotatably provided between the base 5 and the linear guide 11, the linear guide 11 is fixed on the support plate 6, and an arc guide 8 is also provided on the lower end surface of the support plate 6, and the bottom limit of the arc guide 8 is fixed on the base 5; the right end of the support plate 6 is rotatably matched with the rotary shaft 18 fixed on the base 5 and moves along the arc guide under the action of the swing control system. In this embodiment, the rotary shaft is rotatably connected to the support plate 6 through a rotary bearing 17; the slide 15 slides left and right along the linear guide 11 under the control of the movement control system.

[0061] During assembly, the grinding wheel segments are fixed to the slide 15, and the centerline of the grinding wheel segments is collinear with the centerline of the tool grinding wheel and the centerline of the rotary shaft 18. The swing control system includes a swing drive motor 1 and a gear transmission pair. The swing drive motor 1 is connected to the gear transmission pair via a speed reducer 2. The driven gear 7 of the gear transmission pair is fixed to the support plate 6, and its centerline is also collinear with the centerline of the rotary shaft 18. The gear transmission pair also includes a driving gear 3 that meshes with the driven gear 7 and is in driving connection with the speed reducer 2.

[0062] The mobile control system includes a mobile servo motor 13 and a screw transmission pair 14, and the mobile servo motor 13 is connected to the screw transmission pair 14 through a coupling and drives the slide 15 to move, and the screw transmission pair 14 is arranged along the linear track 11, and the mobile servo motor 13 is fixed on the support plate 6 through the motor base 12.

[0063] In this embodiment, a plurality of mounting holes for mounting grinding wheel segments are provided on the slide 15 to meet the requirements of mounting grinding wheel segments of different specifications.

[0064] A method for trimming the inner arc of a CBN grinding wheel segment comprises the following steps:

[0065] (1) Select a diamond grinding wheel as the tool grinding wheel and install it on the tool grinding wheel spindle through a standard tool holder;

[0066] (2) Adjust the yaw angle of the support plate. The swing drive motor drives the gear transmission pair to rotate and drive the support plate to swing around the rotation axis so that the absolute yaw angle of the support plate is 0°;

[0067] (3) Installing the grinding wheel segment on the slide, and controlling the slide to move by the motion control system, setting the position where the grinding wheel segment contacts the tool grinding wheel as the initial dressing position;

[0068] (4) Input the yaw angle;

[0069] (5) Set the constant swing speed N of the grinding wheel segment and calculate the speed F of the tool grinding wheel feeding in the vertical Z direction;

[0070] (6) Set the number of cycles and the amount of single feed, and then start the machine tool;

[0071] (7) Inspect the inner arc surface of the grinding wheel segment after trimming.

[0072] The following describes a specific embodiment of the present invention in detail, combining the contents described herein. Using the present invention's dressing device and a swing-arm inner arc dressing process, a CBN grinding wheel segment for a 1A1-450x23x306.07x6 mill C15 intake and exhaust cam was trimmed. The grinding wheel had a base radius of 218mm, a segment width of 24.5mm, and a chord length of 53.4mm. The inner arc radius R1 of the segment was trimmed to 218mm. The specific method is as follows:

[0073] 1) A flat diamond grinding wheel with a radius R2 of 75 mm and a thickness D of 15 mm was selected as the tool grinding wheel and installed on the tool grinding wheel spindle through a standard tool holder;

[0074] 2) The support plate deflection angle is adjusted through numerical control instructions so that the absolute deflection angle of the support plate is 0°. During this process, the swing drive motor 1 rotates and is decelerated by the reducer 2. The reducer 2 is connected to the driving gear 3, the driving gear 3 is engaged with the driven gear 7, the driven gear 7 is connected to the support plate 6, and the support plate 6 is connected to the circular arc guide rail 8, thereby driving the support plate to swing around the rotating axis 19.

[0075] 3) When trimming the first segment, the grinding wheel segment is mounted on slide 15 using a fixture. The tool grinding wheel position is adjusted using CNC instructions. The absolute coordinate value of this position is X143. The tool grinding wheel rotates, and the CNC instructions slowly move slide 15. The position where the segment and tool grinding wheel meet is set as the initial trimming position. During this process, the servo motor 13 rotates, driving the screw 14. The screw 14 is connected to the slide 15 via a nut. The slide 15 is connected to the guide rail 10, thereby driving the slide 15 to move left and right.

[0076] 4) Input the yaw angle. According to the calculation, the yaw angle θ' = 14.1° + 4° = 18.1° can be obtained.

[0077] 5) Set the segment swing speed N = 30r / min. According to the calculation, the Z-direction feed speed F of the tool grinding wheel is ≤ 8590mm / min. In order to ensure the finishing quality of the segment inner arc, take F = 500mm / min.

[0078] 6) Set the number of cycles to 1, the single feed amount to 0.05mm, and one up and one down as one stroke.

[0079] 7) After starting the machine tool, the inner arc surface of the grinding wheel segment can be automatically finished within 30 seconds. Compared with the traditional interpolation dressing process, the dressing efficiency is increased by more than 2.5 times, which is much higher than other current dressing process methods.

[0080] 8) The inner arc surface of the segment after trimming is inspected. The size deviation of the inner arc radius R1 of the segment is ±0.1. The color coating method test results show that the fitting area between the inner arc surface and the outer diameter of the substrate is greater than 90%, which fully meets the bonding requirements.

[0081] If the terms "first" and "second" are used in this patent to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of describing the present invention and simplifying the description, and the above terms have no special meaning.

[0082] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications are possible without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the claimed invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0083] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

Claims

1. A method for trimming the inner arc of a CBN grinding wheel segment, characterized in that: The dressing device includes a base, a linear guide rail, a slide slidably arranged on the linear guide rail, and a swing control system and a movement control system arranged accordingly; A rotatable support plate is further provided between the base and the linear guide rail, the linear guide rail is fixed on the support plate, and an arc guide rail is further provided on the lower end surface of the support plate, and the bottom limit of the arc guide rail is fixed on the base; The right end of the support plate rotates with the rotary shaft fixed on the base and moves along the arc guide rail under the action of the swing control system; The slide slides left and right along the linear guide rail under the control of the motion control system; During assembly, the grinding wheel segments are fixed on the slide, and the center lines of the grinding wheel segments, the center lines of the tool grinding wheel and the center lines of the rotary axis are all arranged in a collinear manner; The method comprises the following steps: (1) Select a diamond grinding wheel as the tool grinding wheel and install it on the tool grinding wheel spindle through a standard tool holder; (2) Adjust the yaw angle of the support plate. The swing drive motor drives the gear transmission pair to rotate and drive the support plate to swing around the rotation axis so that the absolute yaw angle of the support plate is 0°; (3) Installing the grinding wheel segment on the slide, and controlling the slide to move by the motion control system, setting the position where the grinding wheel segment contacts the tool grinding wheel as the initial dressing position; (4) Input the yaw angle; (5) Set the constant swing speed N of the grinding wheel segment and calculate the speed F of the tool grinding wheel feeding in the up and down Z direction. The speed F of the tool grinding wheel feeding in the up and down Z direction satisfies the following conditions: Let the constant swing speed of the grinding wheel segment be N, the chord length of the grinding wheel segment be L, the inner arc radius be R1, the tool thickness of the tool grinding wheel be D, the distance the tool grinding wheel moves corresponding to one swing of the grinding wheel segment is H, and the angle corresponding to the chord length L is: Among them, Δθ is the yaw angle reserve; The time required to rotate the angle θ' is: To ensure that the inner arc surface is completely trimmed, F·t=H≤D must be satisfied; That is, the speed at which the upper wheel of the tool moves up and down should meet the following requirements: (6) Set the number of cycles and the amount of single feed, and then start the machine tool; (7) Inspect the inner arc surface of the grinding wheel segment after trimming.

2. The method of a CBN grinding wheel segment inner arc dressing device according to claim 1, characterized in that: The swing control system includes a swing drive motor and a gear transmission pair, and the swing drive motor is connected to the gear transmission pair through a reducer, and the driven gear of the gear transmission pair is fixed on the support plate and its center line is also collinear with the center line of the rotating shaft.

3. The method of the CBN grinding wheel segment inner arc dressing device according to claim 2, characterized in that: The gear transmission pair also includes a driving gear meshing with the driven gear for transmission, and the driving gear is transmission-connected to the reducer.

4. The method of a CBN grinding wheel segment inner arc dressing device according to claim 1, characterized in that: The mobile control system includes a mobile servo motor and a screw transmission pair, and the mobile servo motor is connected to the screw transmission pair through a coupling and drives the slide to move, and the screw transmission pair is arranged along a linear track, and the mobile servo motor is fixed on the support plate through a motor base.

5. The method of the CBN grinding wheel segment inner arc dressing device according to claim 1, characterized in that: The slide is provided with a plurality of mounting holes for mounting grinding wheel segments.

6. The method for trimming the inner arc of a CBN grinding wheel segment according to claim 1, characterized in that: The yaw angle in step (4) is calculated as follows: Let the inner arc center of the grinding wheel segment be O, the straight line CC' be the chord length L, the arc length corresponding to the chord length be P, the angle corresponding to the chord length be θ, and the inner arc radius of the grinding wheel segment be R1, then: P=R1θ L=2R1sin(θ / 2) Therefore, In order to ensure that the inner arc of the grinding wheel segment is completely ground, the swing angle reserve Δθ needs to be increased when using the swing arm to grind the arc. Therefore, the swing angle is:

7. The method for trimming the inner arc of a CBN grinding wheel segment according to claim 1, characterized in that: The value of Δθ is 2-4°.

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