Automatic grinding and polishing device for hip joint ball

Abstract

The invention relates to an automatic hip joint ball grinding and polishing device which comprises a machine shell, a control unit and a workbench are arranged in the machine shell, a control display screen is arranged outside the machine shell, and a grinding rotary feeding unit and a ceramic ball rotating and swinging unit are installed on the workbench. Through rotary feeding of the grinding tool and rotary swinging of the ceramic ball, grinding and polishing of the grinding tool on the ceramic ball are completed, when the grinding tool rotates around the axis of the grinding tool, grinding machining is conducted, meanwhile, the ceramic hip joint ball rotates around the axis of the ceramic hip joint ball, so that the conical surface of the grinding tool and the theoretical contact line, tangent to a plane circle, of the ceramic ball rotate relative to the spherical surface; when the grinding tool is fed along the axis, the grinding tool is always tangent to the vertex of the ball, and the spherical surfaces with different diameters can be machined; the grinding efficiency and grinding and polishing precision of the hip joint ball can be remarkably improved, it is ensured that the hip joint ball can meet the surface smoothness and sphericity requirements, and the requirements of different industries for ball surface treatment can be met.

Description

Technical Field

[0001] This invention belongs to the field of hip joint ball processing technology, specifically relating to an automatic grinding and polishing device for hip joint balls. Background Technology

[0002] Bioceramic materials, with their excellent wettability, high wear resistance, extremely high hardness, and good biocompatibility, have become the preferred material for artificial hip joints. Ceramic hip balls are an important component of the hip joint. Due to the high hardness and brittleness of bioceramics, they are very difficult to process. Furthermore, the sphericity and surface roughness requirements for ceramic hip balls are extremely stringent. Traditional metal joint ball processing techniques (turning, electrochemical polishing, etc.) are no longer applicable. Ordinary grinding is inefficient and often results in surface / subsurface damage such as deformation layers, surface microcracks, phase transformation zones, and residual stress, which compromises surface integrity and severely affects the yield and service life of ceramic hip balls. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings and deficiencies of existing technologies by providing an automatic grinding and polishing device for hip joint balls. This device can significantly improve the grinding efficiency and grinding and polishing precision of hip joint balls, ensuring that the hip joint balls can meet the requirements for surface finish and sphericity. It is suitable for mass production and high-quality applications, and can meet the needs of different industries for ball surface treatment, thus having broad market application prospects.

[0004] The technical problem solved by this invention is achieved through the following technical solution: An automatic grinding and polishing device for hip joint balls includes a housing, a control unit and a worktable are provided inside the housing, a control display screen is provided outside the housing, and a grinding rotary feed unit and a ceramic ball rotary swing unit are installed on the worktable. The grinding feed unit includes an electric spindle, a grinding wheel, linear guides, and a servo motor. The grinding wheel is mounted on the front end of the electric spindle. The middle part of the electric spindle is fastened to a U-shaped block by a clamp. Sliders are fixedly connected to both sides of the U-shaped block by bolts. Two linear guides are provided at the lower end of the sliders. The linear guides are fixedly mounted on the worktable. The servo motor is connected to the sliders through a ball screw and drives the sliders to slide along the linear guides, thereby driving the electric spindle to feed along the X-axis. The ceramic ball rotation and swing unit includes a stepper motor, a ceramic ball clamp, and a swing plate. The stepper motor is mounted on the swing plate via a bracket. The end of the stepper motor is locked to the ceramic ball clamp via a motor shaft cutter bar. A ceramic ball is locked onto the ceramic ball clamp. The swing plate is mounted on the inner ring of the external toothed rotary support bearing turntable. The toothed outer ring is fixed on the worktable. The outer ring meshes with the inner ring, causing the swing plate to swing. The axis of the grinding wheel forms a certain angle with the axis of the ceramic ball blank and intersects at the center of the ceramic ball; the control unit controls the operation of the electric spindle, servo motor and stepper motor.

[0005] Furthermore, the ball screw is equipped with a powerful spring and an S-shaped force sensor. The slider on the ball screw is connected to the S-shaped force sensor through a fisheye bearing. The end of the S-shaped force sensor is fixedly connected to the linear guide rail. The S-shaped force sensor measures the pressure value between the mold and the ceramic ball surface generated by the powerful spring in real time and feeds it back to the control unit. The control unit controls the servo motor to adjust the pressure value.

[0006] Furthermore, the grinding wheel and the electric spindle are connected by an ultrasonic tool holder through an elastic sleeve. An ultrasonic transmitter is provided on the side of the ultrasonic tool holder, and the ultrasonic generator is connected to the control unit. The ultrasonic tool holder contains piezoelectric ceramics. The ultrasonic waves emitted by the ultrasonic generator drive the grinding wheel to perform ultrasonic vibration along the axial direction through the ultrasonic tool holder to complete the rotational ultrasonic grinding of the ceramic ball.

[0007] Furthermore, both sides of the U-shaped block are provided with bosses, which cooperate with the side of the slider for positioning in the Y direction.

[0008] Furthermore, the inner surface of the abrasive is a conical surface, and the tangent when the abrasive contacts the ceramic ball passes through the vertex of the sphere.

[0009] The advantages and beneficial effects of this invention are as follows: 1. The automatic grinding and polishing device for hip joint balls of the present invention, with the setting of a grinding rotary feed unit and a ceramic ball rotary oscillation unit, enables the grinding and polishing of the ceramic ball by the grinding wheel through the rotary feed of the grinding wheel and the rotary oscillation of the ceramic ball when the grinding wheel contacts the ceramic ball. When the grinding wheel rotates around its own axis, the grinding process is performed. At the same time, the ceramic hip joint ball rotates around its own axis, causing the theoretical contact line between the conical surface of the grinding wheel and the ceramic ball, which is tangent to the plane circle, to rotate relative to the spherical surface, thereby covering the entire spherical surface to be processed. The processing of the spherical surface is actually formed by the envelope of the theoretical contact line. When the grinding wheel feeds along the axis, it always remains tangent to the vertex of the ball, so that spherical surfaces of different diameters can be processed.

[0010] 2. The automatic grinding and polishing device for hip joint balls of the present invention has an ultrasonic shank connected between the grinding wheel and the electric spindle via an elastic sleeve. An ultrasonic transmitter is provided on the side of the ultrasonic shank, and the ultrasonic generator is connected to the control unit. The ultrasonic shank contains piezoelectric ceramics. The ultrasonic waves emitted by the ultrasonic generator drive the grinding wheel to perform ultrasonic vibration along the axial direction through the ultrasonic shank to complete the rotational ultrasonic grinding of the ceramic ball, which can effectively reduce the grinding force and improve the grinding and polishing accuracy.

[0011] 3. In the automatic grinding and polishing device for hip joint balls of the present invention, the clamp holding the ceramic ball swings together with the swing plate. The swing can effectively remove local residues caused by systematic errors, improve polishing efficiency and accuracy, and reduce labor intensity.

[0012] 4. The automatic grinding and polishing device for hip joint balls of the present invention includes a ball screw equipped with a powerful spring and an S-shaped force sensor. The slider on the ball screw is connected to the S-shaped force sensor through a fisheye bearing. The end of the S-shaped force sensor is fixedly connected to the linear guide rail. The S-shaped force sensor measures the pressure value between the grinding wheel and the surface of the ceramic ball generated by the powerful spring in real time and feeds it back to the control unit. The control unit controls the servo motor to adjust the pressure value, ensuring the stability and consistency of the polishing process. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the present invention (with the casing removed); Figure 3 This is another structural schematic diagram of the present invention (with the casing removed). Figure 4 This is another structural schematic diagram of the present invention (with the casing removed); Figure 5 This is a schematic diagram of the grinding tool structure of the present invention; Figure 6 This is a schematic diagram illustrating the principle of ultrasonic-assisted spherical generating grinding according to the present invention. Figure 7 This is a schematic diagram illustrating the principle of ultrasonic-assisted spherical forming polishing in this invention. Figure 8 This is a diagram showing the motion trajectory of the abrasive particles in this invention; Figure 9 This is a diagram of the abrasive particle motion trajectory of the present invention; Figure 10 This is a physical image of the present invention (with the casing removed).

[0014] Explanation of reference numerals in the attached figures 1-House, 2-Control display screen, 3-Control unit, 4-Worktable, 5-Servo motor, 6-Electric spindle, 7-U-block, 8-Clamp, 9-Ultrasonic transmitter, 10-Ultrasonic shovel, 11-Mold, 12-Stepper motor, 13-Outer ring, 14-Ceramic clamp, 15-Ceramic ball, 16-Inner ring, 17-Swing plate, 18-Linear guide rail, 19-Slider, 20-S-type force sensor, 21-Strong spring, 222-Boss, 23-Conical surface. Detailed Implementation

[0015] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0016] like Figures 1-4 As shown, the present invention proposes an automatic grinding and polishing device for hip joint balls based on the generating method. Its innovation lies in the following: it includes a housing 1, a control unit 3 and a worktable 4 are provided inside the housing, a control display screen 2 is provided outside the housing, and a grinding rotary feed unit and a ceramic ball rotary swing unit are installed on the worktable.

[0017] The grinding feed unit includes an electric spindle 6, a grinding wheel 11, a linear guide rail 18, and a servo motor 5. The grinding wheel is mounted on the front end of the electric spindle. The middle part of the electric spindle is fastened to a U-shaped block 7 by a clamp 8. Slider 19 is fixedly connected to both sides of the U-shaped block by bolts. Two linear guide rails are provided at the lower end of the slider. The linear guide rails are fixedly mounted on the worktable. The servo motor is connected to the slider through a ball screw and drives the slider to slide along the linear guide rails, thereby driving the electric spindle to feed in the X-axis direction. Bosses 22 are provided on both sides of the U-shaped block. The bosses cooperate with the sides of the slider for positioning in the Y-axis direction.

[0018] The ceramic ball rotation and swing unit includes a stepper motor 12, a ceramic ball clamp 14, and a swing plate 17. The stepper motor is mounted on the swing plate via a bracket. The end of the stepper motor is locked to the ceramic ball clamp via a motor shaft cutter bar. A ceramic ball 15 is locked onto the ceramic ball clamp. The swing plate is mounted on the inner ring 16 of the external tooth rotary support bearing turntable. The toothed outer ring 13 is fixed on the worktable. The outer ring meshes with the inner ring, causing the swing plate to swing. The axis of the grinding wheel forms a certain angle with the axis of the ceramic ball blank and intersects at the center of the ceramic ball; the control unit controls the operation of the electric spindle, servo motor and stepper motor.

[0019] like Figure 5 As shown, (1) Grinding: The axis of the grinding wheel forms a certain angle with the axis of the ceramic hip joint ball blank and intersects at the center of the ceramic ball. The inner side of the grinding wheel is a conical surface 23. In an ideal case, the conical surface is tangent to the ceramic ball in a plane circle, which is called the theoretical contact line. Select a suitable grinding wheel conical surface and tilt angle so that the theoretical contact line passes through the vertex of the ball surface. When the grinding wheel rotates around its own axis, grinding is performed. At the same time, the ceramic hip joint ball rotates around its own axis, causing the theoretical contact line to rotate relative to the ball surface, and then covering the entire ball surface to be processed. The processing of the ball surface can be regarded as the formation of the theoretical contact line envelope, such as Figure 7 , 8 As shown, when the grinding wheel feeds along the axis, it always remains tangent to the apex of the ball, which can produce spherical surfaces of different diameters.

[0020] (2) Polishing: Polishing ceramic hip joint balls requires the use of a flexible polishing pad. The contact line between the pad and the ceramic ball is unstable, which makes it impossible to polish the entire spherical surface evenly when using a fixed angle. Ideally, during grinding, when there are no shape or position errors between the ceramic ball and the grinding wheel, the contact line is a complete circle. However, in practical applications, errors are unavoidable. Therefore, when grinding at a fixed angle, local residues are easily generated on the top of the ceramic hip joint ball. This phenomenon is even more obvious during polishing. The ceramic ball rotating and oscillating unit of this invention, centered on the center of the ceramic ball, can effectively remove local residues caused by systematic errors through oscillation. This equipment can be used for the automated production of ceramic hip joint ball grinding and polishing, aiming to solve the problems of low efficiency, poor precision, and high labor intensity of traditional manual polishing.

[0021] To effectively reduce grinding force and improve processing efficiency, ultrasonic vibration is applied to the grinding wheel shaft. Specifically, the grinding wheel 11 is connected to the electric spindle via an elastic sleeve, and an ultrasonic shank 10 is provided on the side of the ultrasonic shank. The ultrasonic generator is connected to the control unit, and the ultrasonic shank contains piezoelectric ceramics. The ultrasonic waves emitted by the ultrasonic generator drive the grinding wheel to perform ultrasonic vibration along the axial direction through the ultrasonic shank to complete the rotational ultrasonic grinding of the ceramic ball.

[0022] The ball screw is equipped with a powerful spring 21 and an S-shaped force sensor 20. The slider on the ball screw is connected to the S-shaped force sensor through a fisheye bearing. The end of the S-shaped force sensor is fixedly connected to the linear guide rail. The S-shaped force sensor measures the pressure value between the mold and the ceramic ball surface generated by the powerful spring in real time and feeds it back to the control unit. The control unit controls the servo motor to adjust the pressure value.

[0023] The present invention's grinding rotary feed unit and ceramic ball rotary oscillation unit enable the grinding and polishing of the ceramic ball by means of the rotary feed of the grinding wheel and the rotary oscillation of the ceramic ball when the grinding wheel contacts the ceramic ball. The grinding process is performed when the grinding wheel rotates around its own axis, while the ceramic hip joint ball rotates around its own axis, causing the theoretical contact line between the conical surface of the grinding wheel and the ceramic ball, which is tangent to the plane circle, to rotate relative to the spherical surface, thereby covering the entire spherical surface to be processed. The processing of the spherical surface is actually formed by the envelope of the theoretical contact line. When the grinding wheel feeds along the axis, it always remains tangent to the apex of the ball, thus enabling the processing of spherical surfaces of different diameters.

[0024] The working principle of this invention is as follows: The control unit starts the electric spindle, stepper motor and servo motor. The servo motor drives the slider to feed along the linear guide. When it moves forward to contact the grinding wheel and the ceramic ball, the grinding wheel rotates under the drive of the electric spindle and the ceramic ball rotates under the drive of the stepper motor. The rotation of the contact surface between the two completes the grinding and polishing of the ceramic ball. Meanwhile, the ultrasonic waves emitted by the ultrasonic generator drive the grinding wheel to perform ultrasonic vibration along the axial direction through the ultrasonic tool holder, thereby completing the rotational ultrasonic grinding of the ceramic ball, reducing grinding force and improving processing efficiency.

[0025] The S-type force sensor can measure the pressure value between the grinding wheel and the ceramic ball surface generated by the strong spring in real time and feed it back to the control unit. The control unit controls the servo motor to adjust the pressure value and ensure the stability of the pressure during grinding and polishing.

[0026] The operation of this invention is controlled by a control unit, which includes a spindle control system, an ultrasonic control system, and a force feedback device. It has a high degree of automation and can accurately coordinate to complete the operation, significantly improving the grinding efficiency and grinding and polishing accuracy of hip joint balls. It ensures that the hip joint balls can meet the surface finish and sphericity requirements, making it suitable for mass production and high-quality applications. It can meet the needs of different industries for ball surface treatment and has broad market application prospects.

[0027] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A hip joint ball auto-grinding and polishing device, characterized by: The utility model provides a kind of ceramic ball rotary ultrasonic grinding device, including shell, control unit and workbench are arranged in the shell, control display screen is arranged outside the shell, grinding rotary feed unit and ceramic ball rotary swing unit are installed on the workbench; The grinding feed unit includes an electric spindle, a grinding tool, linear guides, and a servo motor. The grinding tool is mounted on the front end of the electric spindle. The middle part of the electric spindle is fixedly installed on a U-shaped block by clamping. The U-shaped block is fixedly connected to a sliding block on both sides by bolts. Two linear guides are arranged on the lower end of the sliding block. The linear guides are fixedly installed on the workbench. The servo motor is connected to the sliding block by a ball screw and drives the sliding block to slide along the linear guide, thereby driving the electric spindle to feed in the X-axis direction. The ceramic ball rotary swing unit includes a stepper motor, a ceramic ball clamp, and a swing plate. The stepper motor is installed on the swing plate through a bracket. The end of the stepper motor is connected to the ceramic ball clamp through a motor shaft. The ceramic ball clamp is fixedly installed on a ceramic ball. The swing plate is installed on the inner ring of a rotary support bearing disc with external teeth. The outer ring with teeth is fixed on the workbench. The outer ring engages with the inner ring to drive the swing plate to swing. The axis of the grinding tool intersects the axis of the ceramic ball blank at the center of the ceramic ball. The control unit controls the operation of the electric spindle, the servo motor, and the stepper motor.

2. The hip ball auto grinding and polishing apparatus according to claim 1, wherein: A strong spring and an S-shaped force sensor are arranged on the ball screw. The sliding block on the ball screw is connected to the S-shaped force sensor through a fisheye bearing. The end of the S-shaped force sensor is fixedly connected to the linear guide. The S-shaped force sensor measures the pressure value between the grinding tool and the ceramic ball surface generated by the strong spring in real time and feeds back to the control unit. The control unit controls the servo motor to adjust the pressure value.

3. The hip ball auto grinding and polishing apparatus of claim 1, wherein: An ultrasonic knife handle is connected between the grinding tool and the electric spindle through an elastic sleeve. An ultrasonic transmitter is arranged on the side of the ultrasonic knife handle. The ultrasonic generator is connected to the control unit. The ultrasonic knife handle is internally provided with piezoelectric ceramics. The ultrasonic waves emitted by the ultrasonic generator drive the grinding tool to perform ultrasonic vibration in the axial direction, thereby completing the rotary ultrasonic grinding of the ceramic ball.

4. The hip ball auto grinding and polishing apparatus of claim 1, wherein: Both sides of the U-shaped block are provided with bosses, which cooperate with the side surface of the sliding block for positioning in the Y direction.

5. The hip ball auto grinding and polishing apparatus of claim 1, wherein: The inner surface of the grinding tool is a conical surface. The tangent line when the grinding tool contacts the ceramic ball passes through the apex of the spherical surface.

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