Gear positioning method of numerical control forming gear grinding machine

Abstract

The invention discloses a gear positioning method of a numerical control forming gear grinding machine, which is used for positioning the center and the tooth shape of a gear in the gear grinding process of the numerical control forming gear grinding machine, and belongs to the field of gear clamping and positioning. According to the positioning method, in the tooth groove positioning process of the gear, the machine tool measuring head is controlled to measure the positioning pin shaft to obtain the center position of the positioning pin shaft, the positioning hole, located in the tooth groove center line, in the gear is assembled with the numerical control rotary table positioning pin, the tooth groove center can be accurately obtained, and gear center positioning is achieved. By means of the gear positioning method, the gear machining precision can be improved, the gear center and tooth profile positioning time can be effectively shortened for batch gear manufacturing, and the machining efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of gear clamping and positioning of numerically controlled profile grinding machines, and particularly relates to a gear positioning method for numerically controlled profile grinding machines. Background Art

[0002] Gear grinding is the last process in gear processing. There are other processes before this, such as hobbing and rough milling of gears. How to precisely position the gear center and tooth profile in the gear grinding process from the previous processing steps is the key issue for improving the gear grinding accuracy. If the positioning errors of the gear center and tooth profile cannot be effectively controlled, it is difficult to improve the final machining accuracy of the gear, which will affect the service performance and lifespan of the gear. Currently, gear tooth profile positioning mainly relies on the measurement by a probe and then calculating the tooth profile center position, and gear center positioning mainly depends on manual measurement of the radial runout of the gear rotation using a dial indicator. In batch gear grinding, this positioning method not only makes it difficult to ensure the positioning accuracy, but also increases the duration of the gear grinding process to a certain extent and reduces the processing efficiency.

[0003] In order to improve the accuracy and efficiency of gear grinding, a positioning method that can take into account both gear center positioning and tooth profile positioning is needed. Summary of the Invention

[0004] In view of the deficiencies of the prior art, a gear positioning method for numerically controlled profile grinding machines is provided. To achieve the above object, the technical solution adopted by the present invention is:

[0005] A gear positioning method for numerically controlled profile grinding machines, which is applicable to a five-axis numerically controlled profile grinding machine. The grinding machine includes a machine tool spindle and a rotary table. A probe is installed on the machine tool spindle, and a bracket is installed on the rotary table. The probe points to the center of the rotary table. A cylindrical positioning pin and a diamond-shaped positioning pin are installed on the bracket. The method includes the following specific steps:

[0006] Step 1: Move the probe so that the center line of the probe shaft passes through the center axis of the rotary table. The probe moves along its axis towards the cylindrical positioning pin to the measurement position. The measurement position is that the center of the probe is on the measurement circle. The measurement circle is any circle in the circumferential direction of the rotary table with a point on the center axis of the rotary table as the center and a diameter equal to the diameter of the circle where the center of the cylindrical positioning pin is located. The diameter of the probe is smaller than the radius of the cylindrical positioning pin. If the probe does not come into contact with the cylindrical positioning pin during the movement, the probe stops moving when it reaches the measurement position and proceeds to the next step. If the probe comes into contact with the cylindrical positioning pin, the probe stops moving and is adjusted. The adjustment includes the probe retracting D1 along its axis and the rotary table rotating θ1, where D1 is the diameter of the cylindrical positioning pin, and θ1>θ, and θ is the central angle corresponding to the diameter of the cylindrical positioning pin on the measurement circle. Then, repeat Step 1, and the probe moves along its axis towards the cylindrical positioning pin again;

[0007] Step 2: The turntable rotates counterclockwise. When the probe contacts the left side of the cylindrical locating pin, the turntable stops rotating, and the rotational axis coordinate θ of the turntable when the probe contacts the cylindrical locating pin is obtained. T1 ; The probe is lifted upward by L, the turntable rotates counterclockwise by θ2, and then the probe moves downward by L, where L is the length of the workpiece side of the cylindrical locating pin, and θ2 > θ;

[0008] Step 3: The turntable rotates clockwise. When the probe contacts the right side of the cylindrical locating pin, the turntable stops rotating, and the rotational axis coordinate θ of the turntable when the probe contacts the cylindrical locating pin is obtained. T2 ; The rotational axis coordinate θ of the center of the cylindrical locating pin is obtained according to the rotational axis coordinates of the turntable when the probe contacts the cylindrical locating pin respectively. T3 , where θ T3 = (θ T3 + θ T3 ) / 2; The turntable rotates to the coordinate θ T3 ;

[0009] Step 4: The gear is placed horizontally, and the gear is moved close to the cylindrical locating pin so that the cylindrical locating pin forms a fit with the locating hole on the gear. The center of the gear locating hole is located on the center line of the tooth groove, and this position relationship is ensured by the previous hobbing or milling process;

[0010] Step 5: Taking the cylindrical locating pin as the rotation center, the gear is rotated so that another locating hole on it forms a fit with the telescopic diamond locating pin to achieve the center positioning of the gear; The gear is moved axially along the locating pin so that the lower end face of the gear fits with the upper end face of the bracket.

[0011] The cylindrical locating pin adopts one-plane two-pin positioning, including the upper working surface of the bracket, one cylindrical locating pin, and one diamond locating pin; The cylindrical locating pin and the diamond locating pin are located on any circle on the circumference of the turntable with a point on the central axis of the turntable as the center and a diameter of d2. The cylindrical pin and the diamond pin are circumferentially spaced 180° on this circle, where D2 ∈ (D3, d f ), D3 is the inner diameter of the gear tooth ring, and D f is the root circle diameter.

[0012] The connecting line of the centers of the two pins is perpendicular to the major axis of the diamond pin; The workpiece guiding part of the locating pin is spherical to reduce damage to the gear surface.

[0013] The beneficial effects of the present invention are:

[0014] The present invention adopts a pin shaft positioning method, and simultaneously realizes the center and tooth profile positioning of the gear through the locating pins. In the batch grinding of gears, it is only necessary to calibrate the positioning device when positioning the first gear, which simplifies the process of repeated positioning for each gear in the batch processing of gears, improves production efficiency, and in addition, ensures the positioning accuracy of the gear center and tooth profile, which is beneficial to improving the gear processing accuracy. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0016] Figure 1 is a structural schematic diagram of a numerically controlled form grinding machine;

[0017] Figure 2 is a schematic diagram of the probe measurement and positioning;

[0018] Figure 3 is a schematic diagram of the positioning pin

[0019] Figure 4 is a schematic diagram of the positioning effect

[0020] Specific implementation methods

[0021] The following further describes the present invention in conjunction with the accompanying drawings and embodiments. To clarify the technical problems, technical solutions, implementation processes, and performance demonstrations, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The following will describe various exemplary embodiments, features, and aspects of the present disclosure in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0022] The special term "exemplary" here means "serving as an example, embodiment, or illustrative". Any embodiment described as "exemplary" here does not have to be construed as superior to or better than other embodiments.

[0023] In addition, to better illustrate the present invention, numerous specific details are given in the following specific implementation manners. Those skilled in the art should understand that the present disclosure can be implemented without some specific details. In some instances, methods, means, elements, and circuits well-known to those skilled in the art are not described in detail to highlight the gist of the present disclosure.

[0024] Embodiment 1

[0025] According to Figures 1 - 4 , a gear positioning method for a numerically controlled form grinding machine, the grinding machine is a five-axis machine tool, having three linear axes X, Y, Z and two rotary axes A, C. The origin of the machine tool coordinate system is located at the center of the working surface of the turntable, and the direction away from the turntable is defined as the positive direction.

[0026] A probe is installed on the main shaft of the gear grinding machine, and a bracket is installed on the rotary table of the gear grinding machine. A cylindrical positioning pin shaft and a diamond positioning pin are installed on the bracket. The characteristics are that the specific example is implemented according to the following steps:

[0027] Step 1: Move the probe so that the center line of the probe shaft is parallel to the X-axis and passes through the center axis of the rotary table. The probe moves along the negative X-axis towards the cylindrical positioning pin to the measurement position; the measurement position is that the center of the probe is on the measurement circle. The measurement circle is any circle in the circumferential direction of the rotary table with a point on the center axis of the rotary table as the center and the same diameter as the circle where the center of the cylindrical positioning pin is located. Its radius is denoted as D2. Usually, the diameter of the measurement circle is taken as an integer; the diameter of the probe is smaller than the radius of the cylindrical positioning pin;

[0028] If the probe does not contact the cylindrical positioning pin during the movement, the probe reaches the measurement position, stops moving, and proceeds to the next step;

[0029] If the probe contacts the cylindrical positioning pin, the probe stops moving and is adjusted. The specific adjustment includes the probe retracting D1 along its axis and the rotary table rotating θ1, where D1 is the diameter of the cylindrical positioning pin, θ1>θ, and θ is the central angle corresponding to the diameter of the cylindrical positioning pin on the measurement circle. Then, repeat Step 1, and the probe moves along its axis towards the cylindrical positioning pin again;

[0030] Step 2: The rotary table rotates counterclockwise around the C-axis. When the probe contacts the left side of the cylindrical positioning pin, the rotary table stops rotating, and the rotation axis coordinate θ of the rotary table when the probe contacts the cylindrical positioning pin is obtained T1 ; the probe is lifted upward by L, the rotary table rotates counterclockwise around the C-axis by θ2, and then the probe moves downward by L, where L is the length of the cylindrical positioning pin on the workpiece side, and θ2>θ;

[0031] Step 3: The rotary table rotates clockwise around the C-axis. When the probe contacts the right side of the cylindrical positioning pin, the rotary table stops rotating, and the rotation axis coordinate θ of the rotary table when the probe contacts the cylindrical positioning pin is obtained T2 ; according to the rotation axis coordinates of the rotary table when the probe contacts the cylindrical positioning pin respectively, the rotation axis coordinate θ of the center of the cylindrical positioning pin is obtained T3 where, θ T3 =(θ T3 +θ T3 ) / 2; the rotary table rotates around the C-axis to θ T3 , and the rotation axis coordinate of this position is assigned to the machine tool processing coordinate system, then the center coordinate of the cylindrical positioning pin becomes 0, and the next process can be processed;

[0032] Step 4: The gear is placed horizontally, and the gear is moved close to the cylindrical positioning pin so that the cylindrical positioning pin forms a fit with the positioning hole on the gear. The center of the positioning hole of the gear is located on the center line of the tooth groove, and this position relationship is ensured by the previous hobbing or milling process;

[0033] Specifically, for the gear clamping and positioning in the previous hobbing or milling process, the center of the positioning hole should also be determined by this method so that the center of the first tooth slot machined coincides with the center of the positioning hole.

[0034] Step 5: Rotate the gear with the cylindrical positioning pin as the rotation center so that another positioning hole of the gear forms a fit with the telescopic diamond-shaped positioning pin to achieve gear center positioning; move the gear axially along the positioning pin so that the lower end face of the gear fits with the upper end face of the bracket. The positioning effect is shown in Figure 4 .

[0035] The above-described examples are only for describing the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the concept of the present invention, various variations and improvements made by ordinary engineering and technical personnel in the field to the technical solution of the present invention should fall within the protection scope of the present invention. The technical content claimed by the present invention has been fully recorded in the claims.

Claims

1. A gear positioning method for a numerically controlled form grinding machine, which is applicable to a five-axis numerically controlled form grinding machine. The grinding machine includes a machine tool spindle and a turntable. A probe is installed on the machine tool spindle, and a bracket is installed on the turntable. The probe points to the center of the turntable. A cylindrical positioning pin shaft and a diamond-shaped positioning pin are installed on the bracket. It is characterized in that, It includes the following specific steps: Step 1: Move the probe so that the center line of the probe axis passes through the center axis of the turntable. The probe moves along its axis towards the cylindrical locating pin to the measuring position. The measuring position is that the center of the probe is on the measuring circle, and the measuring circle is any circle in the circumferential direction of the turntable with a point on the center axis of the turntable as the center and a diameter equal to that of the circle where the center of the cylindrical locating pin is located; the diameter of the probe is smaller than the radius of the cylindrical locating pin; if the probe does not come into contact with the cylindrical locating pin during the movement, the probe stops moving when it reaches the measuring position and proceeds to the next step; if the probe comes into contact with the cylindrical locating pin, the probe stops moving and is adjusted. The adjustment includes the probe retracting D1 along its axis and the turntable rotating θ1, where D1 is the diameter of the cylindrical locating pin, θ1>θ, and θ is the central angle corresponding to the diameter of the cylindrical locating pin on the measuring circle. Then, repeat Step 1, and the probe moves along its axis towards the cylindrical locating pin again; Step 2: The turntable rotates counterclockwise. When the probe contacts the left side of the cylindrical locating pin, the turntable stops rotating, and the rotational axis coordinate θ of the turntable when the probe contacts the cylindrical locating pin is obtained. T1 ; The probe is lifted upward by L, the turntable rotates counterclockwise by θ2, and then the probe moves downward by L, where L is the length of the workpiece side of the cylindrical locating pin and θ2 > θ. Step 3: The turntable rotates clockwise. When the probe contacts the right side of the cylindrical locating pin, the turntable stops rotating, and the rotation axis coordinate θ of the turntable when the probe contacts the cylindrical locating pin is obtained. T2 ; The rotation axis coordinate of the center of the cylindrical locating pin is obtained based on the rotation axis coordinates of the turntable when the probe contacts the cylindrical locating pin respectively. T3 , where θ T3 =(θ T3 +θ T3 ) / 2; The turntable rotates to the coordinate θ T3 ; Step 4: Place the gear horizontally, move the gear close to the cylindrical locating pin so that the cylindrical locating pin forms a fit with the locating hole on the gear. The center of the gear locating hole is located on the center line of the tooth groove, and this position relationship is ensured by the previous hobbing or milling process; Step 5: With the cylindrical locating pin as the rotation center, rotate the gear so that another locating hole on it forms a fit with the telescopic diamond locating pin to achieve the center positioning of the gear; move the gear along the axial direction of the locating pin so that the lower end face of the gear fits with the upper end face of the bracket; 2. The gear positioning method of a numerically controlled form grinding machine according to claim 1, characterized in that: The cylindrical locating pin adopts one-plane two-pin positioning, including the upper working surface of the bracket, a cylindrical locating pin and a diamond locating pin; the cylindrical locating pin and the diamond locating pin are located on any circle on the circumferential direction of the turntable with a point on the central axis of the turntable as the center of the circle and a diameter of d2. The cylindrical pin and the diamond pin are circumferentially spaced 180° on this circle, where D2 ∈ (D3, d f ), D3 is the inner diameter of the gear ring, and D f is the root circle diameter.

3. A gear positioning method for a numerically controlled form grinding machine according to claim 2, characterized in that: The connecting line between the centers of the two pins is perpendicular to the long axis of the diamond pin; the workpiece guiding part of the locating pin is spherical to reduce damage to the gear surface.

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