Numerical control gear hobbing machine tooth thickness compensation method and device and numerical control gear hobbing machine

Abstract

The invention discloses a numerical control gear hobbing machine tooth thickness compensation method and device and a numerical control gear hobbing machine. The numerical control gear hobbing machine tooth thickness compensation method comprises the following steps that the first angle variable quantity of an encoder and the common normal variable quantity of a test workpiece which are determined and obtained through a test are obtained; calculating the radius according to the first angle variable quantity and the common normal variable quantity of the test workpiece; in response to a received heat engine cutting instruction, acquiring an angle value of the encoder when the machine tool is at a zero position, an X coordinate value of the machine tool in a heat engine state and an angle value of the encoder at the position, and calculating to obtain a second variable quantity of the encoder on an X axis in the heat engine state; according to the second variable quantity, the Z-axis coordinate of the tooth width center of the workpiece to be machined and the Z-axis coordinate of the gear rack meshing point, a cutting compensation value is obtained through calculation; and compensating the X axis of the cutter according to the cutting compensation. The cutting compensation amount can be calculated, the compensation precision is high, and time and labor are saved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of numerical control gear hobbing machine, and particularly relates to a numerical control gear hobbing machine tooth thickness compensation method and device and numerical control gear hobbing machine. BACKGROUND

[0002] The structure of the numerical control gear hobbing machine is shown in the figure, which comprises a guide rail 4, a machine tool arranged on the guide rail, a fixing structure for fixing a workpiece 3, a cutter 1 for cutting the workpiece and fixed on the machine tool, a rack 51 arranged on the machine tool and parallel to the guide rail 4, and a gear 52 engaged with the rack. Among them, the guide rail and the rack are parallel to the X axis of the numerical control gear hobbing machine coordinate axis, and the coordinate center of the numerical control gear hobbing machine is point A. Figure 1 The numerical control gear hobbing machine with the above structure, when continuously processing, the cooling liquid takes away the cutting heat and sprays in the middle part of the machine tool, i.e. the cutting area, and then flows into the chip remover and the water tank. The bed body is heated and presents a convex state, so that the two side columns are respectively inclined outward, causing the actual positions of the cutter and the workpiece to be far apart, which affects the yield of the workpiece. In order to improve the yield of the workpiece, the existing method is to use programming, combined with the change of the tooth thickness of the workpiece during actual cutting, to artificially explore the law of tooth thickness change and time or workpiece processing quantity, and to input the data into the machine tool for cutting.

[0003] The existing method has the following problems:

[0004] 1. When the workpiece type is changed or the air temperature changes greatly, the parameters need to be adjusted again, which is time-consuming and laborious. 2. Some manufacturers heat the machine before processing to make the machine reach a thermal equilibrium state, and then continuously cut, which wastes a lot of processing time, and the machine cannot be stopped in the middle, otherwise it needs to be preheated again. Some manufacturers configure a cooling temperature control device on the cooling box to control the oil temperature and reduce the influence of the temperature rise of the cooling liquid on the bed body, but it cannot eliminate the thermal deformation of the bed body and cannot accurately control the tooth thickness of the workpiece. Some manufacturers pre-bury multiple temperature sensors in the machine and try to obtain the relationship between the temperature changes of the temperature sensors and the thermal changes of the machine, but the mathematical model is complex and the temperature of the measurement point is single and random, which cannot accurately reflect the thermal change amount of the machine.

[0005] SUMMARY In order to solve the problems of low precision and time-consuming and laborious of the existing method, the present application provides a numerical control gear hobbing machine tooth thickness compensation method and device and numerical control gear hobbing machine.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] The first aspect of the present application discloses a numerical control gear hobbing machine tooth thickness compensation method, comprising the following steps: ​The first angle change amount of the encoder and the common normal line change amount of the test workpiece gear are obtained through test, the encoder is coaxially installed with the gear, the angle change amount is the difference between the angle of the numerical control gear rolling machine when cutting the test workpiece machine tool by one position in the cold state and the angle of the numerical control gear rolling machine when cutting the test workpiece machine tool by one position in the hot state, and the common normal line change amount is the difference between the common normal lines of the test workpieces cut in the cold state and the hot state respectively; The first change amount of the encoder on the X axis is calculated according to the first angle change amount and the gear pitch circle diameter; The difference of the tool center on the X axis is calculated according to the common normal line change amount of the test workpiece gear; The radius R is calculated according to the first change amount of the encoder on the X axis and the difference of the tool center on the X axis; In response to receiving the hot machine cutting instruction, the angle value of the encoder when the machine tool is at zero position, the X coordinate value of the machine tool in the hot state and the angle value of the encoder at the position are obtained; The second change amount of the encoder on the X axis in the hot state is calculated according to the angle value of the encoder when the machine tool is at zero position, the X coordinate value of the machine tool in the hot state and the angle value of the encoder at the position; The cutting compensation value is calculated according to the second change amount, the radius R, the Z axis coordinate of the workpiece gear width center and the Z axis coordinate of the gear rack meshing point; The tool X axis is compensated according to the cutting compensation value.

[0008] The second aspect of the present application discloses a numerical control gear rolling machine tooth thickness compensation device, which comprises a memory and a controller connected in sequence, the memory stores a computer program, and the controller is used for reading the computer program and executing the numerical control gear rolling machine tooth thickness compensation method.

[0009] The third aspect of the present application discloses a numerical control gear rolling machine, which comprises a guide rail, a machine tool arranged on the guide rail, a fixing structure for fixing a workpiece, a tool for cutting the workpiece and fixed on the machine tool, a rack arranged on the machine tool and parallel to the guide rail, a gear meshing with the rack, a control unit and an information input unit, wherein the machine tool is signal connected to the control unit, The control unit is the numerical control gear rolling machine tooth thickness compensation device, The gear is coaxially installed with an encoder signal connected with the numerical control gear rolling machine tooth thickness compensation device; The information input unit is used for obtaining the first angle change amount of the encoder and the common normal line change amount of the test workpiece determined through test.

[0010] Compared with the prior art, the present application has at least the following advantages and beneficial effects: The present application adds an encoder on the gear to measure the moving distance of the gear relative to the rack, and further calculates the cutting compensation amount, which has high compensation accuracy and saves time and effort. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0012] Figure 1 Structure diagram of the cold state of the numerical control gear rolling machine; Figure 2 Structure diagram of the hot state of the numerical control gear rolling machine. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0014] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0015] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0016] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0017] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, or the orientation or positional relationship commonly understood by those skilled in the art, and 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, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0018] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0019] When the CNC hobbing machine does not deform, that is, in the normal temperature cold state, the movement distance of the gear relative to the rack is consistent with the machine tool X-axis coordinate. When the CNC hobbing machine deforms, that is, in the hot state, the columns are respectively inclined outward, resulting in a certain degree of deviation between the movement distance of the gear relative to the rack and the machine tool X-axis coordinate, and the deviation is mainly in the X-axis direction, and the Z-axis changes very little and can be ignored. During the tilting of the two side columns, the tilting angle is small, and the tilting center of rotation is approximately at the same position, and the actual position size of the tilting center of rotation is obtained through the thermal change data occurring during actual cutting of the machine tool, to provide the parameter R for program compensation. For this, the present scheme coaxially installs an encoder on the gear to real-time collect the movement distance of the gear relative to the rack, and based on this, the present application discloses a CNC hobbing machine tooth thickness compensation method, which can be executed by a CNC hobbing machine tooth thickness compensation device, and the compensation is a control unit of the CNC hobbing machine. Specifically, the compensation method comprises the following steps S01-S08. It should be noted that the step identifier in the present scheme is only for the convenience of describing the method, and does not constitute a sequence limitation, and the sequence of each step is subject to the language description, and subject to the sequence of each signal.

[0020] Step S01: obtaining a first angle change amount of an encoder and a common normal line change amount of a test workpiece gear, the encoder being coaxially installed with the gear, the first angle change amount being a difference between an angle of a numerical control gear rolling machine when cutting a test workpiece machine to move a position in a cold state and an angle of the numerical control gear rolling machine when cutting the test workpiece machine to move the position in a hot state, and the common normal line change amount being a difference between common normal lines of the test workpieces respectively cut in the cold state and the hot state.

[0021] Before the numerical control gear rolling machine is shipped, two workpieces are used to perform test and test, to obtain an angle change amount of the encoder and a gear common normal line change amount of the test workpiece. The parameters of the test workpiece are set by the manufacturer, and are not necessarily consistent with the parameters of the workpiece to be machined by the subsequent user.

[0022] During the test, the test workpiece is cut in the cold state and the hot state respectively to obtain two finished gear products. At this time, the common normal line micrometer is used to measure the two gear products respectively, and the common normal line change amount of the test workpiece can be obtained.

[0023] During the test, the machine tool is controlled to move in the cold state and the hot state respectively, and the first angle change amount is calculated according to the angle value of the encoder at the same position.

[0024] Step S02: calculating a first change amount ΔL of the encoder on the X axis according to the first angle change amount and the gear pitch circle diameter.

[0025] The gear pitch circle is a parameter of the gear 52, which can be directly calculated and written into the control unit.

[0026] The first change amount ΔL of the encoder on the X axis is: ΔL = σ / 360*D*π, In the formula, σ is the angle change amount of the encoder, D is the gear pitch circle diameter, and π is the circular constant.

[0027] Step S03: calculating a difference value of the tool center on the X axis according to the test workpiece gear pressure angle and the common normal line change amount.

[0028] The workpiece is cut in the cold state and the hot state, and the common normal line of the machined gear is different under the same program due to the influence of thermal deformation. The actual change amount of the tool and the workpiece left and right position, that is, the difference value ΔX of the tool center on the X axis, can be obtained through the change amount of the common normal line.

[0029] At this time, ΔX = ΔW / (2 *sina), In the formula, ΔW is the common normal line change amount of the test workpiece, and a is the gear pressure angle of the test workpiece.

[0030] Step S04: according to the first change amount of the encoder on the X axis, the difference value of the cutter center on the X axis, the diameter R is calculated.

[0031] Wherein, R=△L / ((△L-△X) / Z3), In the formula, Z3 is the height difference of the test workpiece and the gear rack meshing point, that is, the difference value of the Z axis coordinate of the gear rack meshing point and the Z axis coordinate of the test workpiece center.

[0032] Step S05: in response to receiving the hot engine cutting instruction, the angle value of the encoder of the machine tool at zero position, the X coordinate value of the machine tool in the hot engine state and the angle value of the encoder at this position are obtained.

[0033] Step S06: according to the angle value of the encoder of the machine tool at zero position, the X coordinate value of the machine tool in the hot engine state and the angle value of the encoder at this position, the second change amount △L' of the encoder on the X axis in the hot engine state is calculated.

[0034] Specifically, △L´=(θ1-θ2) / 360*D*π-X1, In the formula, θ1 is the angle value of the encoder of the machine tool at zero position, X1 is the X coordinate value of the machine tool in the hot engine state, and θ2 is the angle value of the position encoder of the machine tool in the hot engine state at the X coordinate value.

[0035] Step S07: according to the second change amount △L', the radius R, the Z axis coordinate of the tooth width center of the workpiece to be machined and the Z axis coordinate of the gear meshing point, the cutting compensation value is calculated.

[0036] Specifically, △X´=△L´ / R*(R-(Z2-Z1)), In the formula, △X' is the cutting compensation value, Z2 is the Z axis coordinate of the gear rack meshing point, and Z1 is the Z axis coordinate of the tooth width center of the workpiece to be machined.

[0037] Step S08: according to the cutting compensation value, the cutter X axis is compensated.

[0038] The first aspect of the application provides a point cloud heat map drawing device, which comprises a memory and a controller connected in sequence, the memory stores a computer program, and the controller is used for reading the computer program and executing the numerical control gear hobbing machine tooth thickness compensation method in the first aspect. The device is a control unit of the numerical control gear hobbing machine.

[0039] The third aspect of the present application discloses a numerical control gear hobbing machine, comprising a guide rail 4, a machine tool arranged on the guide rail, a fixing structure for fixing a workpiece 3, a cutter 1 for cutting the workpiece and fixed on the machine tool, a rack 51 arranged on the machine tool and arranged in parallel with the guide rail 4, a gear 52 engaged with the rack, a control unit and an information input unit, wherein the machine tool is signal connected to the control unit, The control unit is the numerical control gear hobbing machine tooth thickness compensation device of claim 7, The gear coaxially installs an encoder 2 signal connected with the numerical control gear hobbing machine tooth thickness compensation device; The information input unit is used for obtaining the first angle change amount of the encoder and the public normal line change amount of the test workpiece gear determined by the test.

[0040] The working principle of the numerical control gear hobbing machine for controlling the cutter cutting is the same as the prior art, and will not be repeated here.

[0041] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to part of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A tooth thickness compensation method for a CNC gear hobbing machine, characterized in that: The following steps are involved: Obtaining a first angle variation of the encoder and a common normal variation of the test workpiece, obtained through testing, wherein the encoder is coaxially mounted with the gear. The angle variation is the difference between the angle of the CNC gear hobbing machine when the machine tool moves a certain position while cutting the test workpiece in a cold state and the angle of the CNC gear hobbing machine when the machine tool moves the same position while cutting the test workpiece in a hot state. The common normal variation is the difference between the common normals of the test workpiece cut in the cold state and the hot state, respectively. Calculating a first variation ΔL of the encoder on the X-axis according to the first angle variation and the gear pitch circle diameter; The difference △X of the tool center on the X axis is calculated based on the gear pressure angle and the normal line change of the test workpiece; The radius R is calculated based on the first variation ΔL of the encoder on the X-axis and the difference ΔX of the tool center on the X-axis; In response to receiving a hot machine cutting instruction, obtaining an angle value of an encoder when the machine tool is at zero position, an X coordinate value of the machine tool in a hot machine state, and an angle value of the encoder at that position; The second variation ΔL´ of the encoder on the X-axis in the hot state is calculated based on the angle value of the encoder when the machine tool is at zero position, the X coordinate value of the machine tool in the hot state, and the angle value of the encoder at this position; The cutting compensation value is calculated based on the second variation ΔL', the radius R, the Z-axis coordinate of the center of the tooth width of the workpiece to be machined, and the Z-axis coordinate of the meshing point of the gear rack; The tool X axis is compensated according to the cutting compensation value.

2. The tooth thickness compensation method for a CNC gear hobbing machine according to claim 1, characterized in that: The first variation ΔL of the encoder on the X-axis is calculated based on the first angle variation and the gear pitch circle diameter: △L=σ / 360*D*π, Where σ is the angular variation of the encoder and D is the pitch circle diameter of the gear.

3. The tooth thickness compensation method for a CNC gear hobbing machine according to claim 1, characterized in that: The difference ΔX of the tool center on the X-axis is calculated based on the gear pressure angle and the normal line variation of the test workpiece: △X=△W / (2*sina); Where △W is the change in the normal line of the test workpiece, and a is the gear pressure angle of the test workpiece.

4. The tooth thickness compensation method for a CNC gear hobbing machine according to claim 1, characterized in that: The radius R is calculated based on the first variation ΔL of the encoder on the X-axis and the difference ΔX of the tool center on the X-axis: R=△L / ((△L-△X) / Z3), Where R is the radius, and Z3 is the height difference between the center of the test workpiece and the meshing point of the gear rack.

5. The tooth thickness compensation method for a CNC gear hobbing machine according to claim 1, characterized in that: The second variation ΔL´ of the encoder on the X-axis in the hot state is calculated based on the angle value of the encoder when the machine tool is at zero position and the angle value of the encoder at any position in the hot state: △L´=(θ1-θ2) / 360*D*π-X1, Where θ1 is the angle value of the encoder when the machine tool is at zero position, X1 is the X coordinate value of the machine tool in the hot state, and θ2 is the angle value of the position encoder when the machine tool is at the X coordinate value in the hot state.

6. The tooth thickness compensation method for a CNC gear hobbing machine according to claim 1, characterized in that: The cutting compensation value is calculated based on the second variation ΔL', the radius R, the Z-axis coordinate of the center of the tooth width of the workpiece to be machined, and the Z-axis coordinate of the gear rack meshing point: △X´=△L´ / R*(R-(Z2-Z1)), Where △X' is the cutting compensation value, Z2 is the Z-axis coordinate of the gear rack meshing point, and Z1 is the Z-axis coordinate of the center of the tooth width of the workpiece to be machined.

7. A tooth thickness compensation device for a CNC gear hobbing machine, comprising a memory and a controller in communication with each other, wherein a computer program is stored in the memory, and wherein: The controller is used to read the computer program and execute the tooth thickness compensation method for a CNC gear hobbing machine according to any one of claims 1 to 6.

8. A CNC gear hobbing machine, comprising a guide rail, a machine tool mounted on the guide rail, a fixing structure for fixing a workpiece, a tool for cutting the workpiece and fixed to the machine tool, a rack mounted on the machine tool and arranged parallel to the guide rail, a gear meshing with the rack, a control unit, and an information input unit, wherein: The machine tool signal is connected to the control unit, characterized in that, The control unit is a tooth thickness compensation device for a CNC gear hobbing machine as described in claim 7, The gear is coaxially mounted with an encoder connected to the signal of the tooth thickness compensation device of the CNC gear hobbing machine; The information input unit is used to obtain the first angle variation of the encoder and the common normal variation of the test workpiece determined by the test.

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