Gear processing machine tool outer support top pressure adjusting structure

Abstract

This invention belongs to the field of gear processing technology. It relates to a center pressure adjustment structure for an external support of a gear processing machine tool, comprising an external support on which a center is mounted. The external support is mounted on a ball screw driven by a servo motor. The external support has a stepped hole, and a ball screw nut is disposed within the stepped hole. One end of the ball screw nut has a spring sleeve and a first elastic body, the spring sleeve being fixedly connected to the ball screw nut. The first elastic body is disposed within the spring sleeve, one end of which abuts against the end face of the stepped hole, and the other end abuts against the spring sleeve. The other end of the ball screw nut has a second elastic body and a receiving plate. The receiving plate is fixedly connected to the external support, one end of the second elastic body abuts against the ball screw nut, and the other end abuts against the receiving plate. The external support is elastically floating on the ball screw nut via the first and second elastic bodies. This invention achieves three-stage adjustment of the center pressure, making it applicable to a wider range of workpieces.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of gear machining, and relates to a top pressure adjusting structure of an outer support of a gear machining machine tool. BACKGROUND

[0002] In the process of machining gears by a gear machining machine tool, the gears need to be clamped by an outer support top. In the machining process, sometimes the gears are small and have poor rigidity, and the clamping force cannot be adjusted, so the clamping force is fixed. When the workpiece changes, the required pressure also changes. When the clamping force of the top is too small, the required force for fixing the workpiece cannot be met, and the workpiece will deviate in the machining process, resulting in unqualified machining precision. When the clamping force of the top is too large, it exceeds the required clamping force for clamping the workpiece, resulting in deformation of the workpiece or the clamp, which also leads to unqualified machining precision of the workpiece. Therefore, the conventional outer support structure cannot meet the requirement of different clamping forces. SUMMARY

[0003] Therefore, the present application aims to solve the problem of adjusting the clamping force of the top as required, and provides a top pressure adjusting structure of an outer support of a gear machining machine tool.

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

[0005] A top pressure adjusting structure of an outer support of a gear machining machine tool, comprising an outer support provided with a top, wherein the outer support is arranged on a ball screw driven by a servo motor, the outer support is provided with a stepped hole, a ball screw nut is arranged in the stepped hole, one end of the ball screw nut is provided with a spring sleeve and a first elastic body, and the spring sleeve is fixedly connected with the ball screw nut; the first elastic body is arranged in the spring sleeve, one end of the first elastic body abuts against an end face of the stepped hole, and the other end abuts against the spring sleeve; the other end of the ball screw nut is provided with a second elastic body and a connecting disc; the connecting disc is fixedly connected with the outer support, one end of the second elastic body abuts against the ball screw nut, and the other end abuts against the connecting disc; and the outer support is elastically and floatingly arranged on the ball screw nut through the first elastic body and the second elastic body.

[0006] Further, a gasket is arranged between the first elastic body and the outer support, and the initial compression amount of the first elastic body is adjusted through the gasket.

[0007] Further, a stop opening matched with the stepped hole is arranged on the connecting disc, an end face of the stop opening abuts against the second elastic body, and the initial compression amount of the second elastic body is adjusted by changing the depth of the stop opening.

[0008] Further, the first elastic body and the second elastic body are spring or polyurethane rings.

[0009] Further, the output mode of the servo motor adopts position loop control and torque control.

[0010] Further, the elastic modulus of the first elastic body is less than the elastic modulus of the second elastic body.

[0011] Further, the top pressure adjusting structure of the gear processing machine tool outer support in the application adjusts the size of the top pressure by controlling the relative distance between the ball screw nut and the workpiece through the servo motor driving the ball screw nut, thereby changing the compression amount of the first elastic body and the second elastic body.

[0012] Further, the process of the ball screw nut driving the top to press the workpiece is divided into three change stages.

[0013] The first stage is that, in the process of the compression amount of the second elastic body changing from the initial state to zero, the change of the top pressure is controlled by the elastic force difference between the first elastic body and the second elastic body.

[0014] The second stage is that, after the compression amount of the second elastic body changes to zero, the change of the top pressure is controlled by the elastic force of the first elastic body.

[0015] The third stage is that, when the compression amount of the first elastic body reaches the maximum, that is, the outer support directly abuts against the spring sleeve, the change of the top pressure is controlled by the output of the servo motor.

[0016] Further, in the change process from the first stage to the third stage, the top pressure changes from small to large.

[0017] In the first stage and the second stage, the servo motor adopts position loop control mode; in the third stage, the servo motor adopts torque control mode.

[0018] The beneficial effects of the application are as follows:

[0019] The top pressure in the application changes in three stages according to the different compression amounts of the two elastic bodies, in the process of the compression amount of the second elastic body changing from the initial state to zero, the change of the top pressure is the elastic force difference between the first elastic body and the second elastic body, after the compression amount of the second elastic body changes to zero, the change of the top pressure is the elastic force of the first elastic body, when the compression amount of the first elastic body reaches the maximum, that is, the outer support contacts the spring sleeve, the change of the top pressure is the output change of the servo motor. The top pressure can be adjusted according to different requirements by controlling the first elastic body, the second elastic body and the servo motor, thereby overcoming the defect that the traditional structure cannot guarantee the machining precision because it cannot adjust the clamping force.

[0020] Additional advantages, objects, and features of the application will be apparent to those skilled in the art upon examination of the following specification. It is intended that the application not be limited by the disclosed BRIEF DESCRIPTION OF DRAWINGS

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

[0022] Fig. 1 The figure is a schematic diagram of the top pressure adjustment structure of the outer support of the gear processing machine tool.

[0023] Fig. 2 The figure is a curve of the change of the top pressure of the outer support.

[0024] Reference signs: 1 - top; 2 - outer support; 3 - ball screw; 4 - ball screw nut; 5 - connecting disc; 6 - second elastic body; 7 - spring sleeve; 8 - first elastic body; 9 - gasket. DETAILED DESCRIPTION

[0025] The present application can also be embodied in a different specific form, and the specific details disclosed herein are not to be interpreted as limiting but merely for the purpose of illustration. The following examples are provided by way of illustration and thus should not be construed as limiting the scope of the present application. The features of the examples described below can be combined with each other, if not incompatible, in order to produce further embodiments of the application.

[0026] The drawings are merely schematic and are not drawn to scale, and should not be considered as limiting the present application. Some components of the drawings can be omitted, enlarged or reduced in order to better illustrate the embodiments of the present application. It is understood by those skilled in the art that some well-known structures and their descriptions can be omitted from the drawings.

[0027] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components; in the description of the present application, it is understood that if the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back" and the like are based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0028] Please refer to Figs. 1-2 The present application is a kind of gear processing machine tool outer support top pressure adjustment structure, including the outer support 2 of installation top 1, outer support 2 is installed on the ball screw 3 driven by servo motor, outer support 2 is provided with stepped hole, ball screw nut 4 is arranged in the stepped hole, one end of ball screw nut 4 is provided with spring sleeve 7 and first elastic body 8, spring sleeve 7 is fixedly connected with ball screw nut 4;First elastic body 8 is arranged in spring sleeve 7, one end of first elastic body 8 abuts against the end face of stepped hole, and the other end abuts against spring sleeve 7;The other end of ball screw nut 4 is provided with second elastic body 6 and connecting disc 5;Connecting disc 5 is fixedly connected with outer support 2, one end of second elastic body 6 abuts against ball screw nut 4, and the other end abuts against connecting disc 5;Outer support 2 is elastically floatingly installed on ball screw nut 4 through first elastic body 8 and second elastic body 6.

[0029] The gasket 9 is arranged between the first elastic body 8 and the outer support 2, and the initial compression amount of the first elastic body 8 can be adjusted through the gasket 9. The connecting disc 5 is provided with a stop opening matched with the stepped hole, and the end face of the stop opening abuts against the second elastic body 6. The initial compression amount of the second elastic body 6 can be adjusted by changing the depth of the stop opening.

[0030] In the embodiment, the first elastic body 8 is a cylindrical spring, and the second elastic body 6 is a polyurethane ring. The elastic modulus of the first elastic body 8 is greater than that of the second elastic body 6.

[0031] The output mode of the servo motor can adopt two control modes of position loop control and torque control.

[0032] By using the above-mentioned gear processing machine tool outer support 2 top pressure adjustment structure, the top pressure curve of three stages is calculated, so that the stage corresponding to the required top pressing force of the workpiece is selected according to the required top pressing force of the workpiece, and the control of the moving displacement of the ball screw nut 4 is carried out. The relative distance between the ball screw nut 4 and the workpiece is controlled by driving the ball screw nut 4 by the servo motor, so as to change the compression amount of the first elastic body 8 and the second elastic body, and the adjustment of different top 1 pressure sizes is realized.

[0033] The process of ball screw nut 4 driving the top 1 to press the workpiece, the top 1 pressure adjustment is divided into three stages of change:

[0034] The first stage is that in the process of the compression amount of the second elastic body 6 changing from the initial state to zero, the change of the pressure of the top 1 is controlled by the difference between the elastic force of the first elastic body 8 and the second elastic body 6;

[0035] The second stage is that when the compression amount of the second elastic body 6 changes to zero, the change of the pressure of the top 1 is controlled by the elastic force of the first elastic body 8;

[0036] The third stage is that when the compression amount of the first elastic body 8 reaches the maximum, that is, the outer support 2 directly abuts against the spring sleeve 7, the change of the pressure of the top 1 is controlled by the output of the servo motor.

[0037] From the first stage to the third stage, the pressure of the top 1 changes from small to large. In the first stage and the second stage, the servo motor adopts a position loop control mode; in the third stage, the servo motor adopts a torque control mode.

[0038] The following is a specific implementation example:

[0039] Servo motor torque: T = 8 NM, reducer transmission ratio i = 5, ball screw 3 diameter and pitch 50*10; outer support 2 weight G = 300 kg; select cylindrical helical compression spring specification: 8*65*110, K2 = 33 N / mm, select the polyurethane ring of grade 8270, and the elastic modulus E' = 60 kgf / cm 2 from the table; polyurethane spring pad size: inner diameter d = 65*outer diameter D = 90*free height H01 = 35.

[0040] FA = (TA*2*π*η*i) / L

[0041] In the formula: FA- screw thrust (kgf), TA- motor torque (kgf*mm), η- transmission efficiency (0.90-0.95), L- screw pitch (mm).

[0042] Polyurethane ring elastic force calculation:

[0043] Inner diameter d = 65 mm; outer diameter D = 90 mm; free height H 01 = 35 mm; elastic modulus E' = 60 kgf / cm 2 ; shape factor K = (D 2 -d 2 ) / [4H 01 (D+d)] = 0.178; take the correction coefficient c = 1.3;

[0044] Elastic modulus E = c*E' = 78 kgf / cm2 ;

[0045] Static stiffness P = E * A / H01 = 78 * (4.5 2 -3.25 2 ) * π / H 01 * 10 = 678 N / mm.

[0046] The elastic force of the outer support 2 in the static balance state is calculated:

[0047] Preliminary selection: H1 = 23 mm, L = 30 mm, H2 = 100 mm, B = 153 mm;

[0048] H 01 = 35 mm;

[0049] K1 = P = 678 N / mm;

[0050] H 02 = 110 mm;

[0051] K2 = 33 N / mm (check table);

[0052] G = 3000 N;

[0053] L = 30 mm;

[0054] B = 153 mm;

[0055] H1 = (K1 * H 01 -K2 * (H 02 -B + L) - G) / (K1 + K2) = 29.76 mm;

[0056] H2 = B - H1 - L = 93.23 mm;

[0057] The outer support 2 and the ball screw nut 4 are lowered, and the pressure control of the center 1 is controlled:

[0058] 1) The first stage, when the center 1 of the outer support 2 presses against the workpiece, the pressure of the center 1 of the outer support 2 against the workpiece is Fn1, and the movement of the outer support 2 relative to the ball screw nut 4 is ΔZ, at this time the servo motor adopts position loop control, at this time the clamping force of the outer support 2 is:

[0059] Fn1 = (K1 + K2) * ΔZ = 3726 N

[0060] When ΔZ = 0 moves to the maximum ΔH1: ΔH1 = H 01 -H1 = 5.238 mm; Fn1 = 3726 N.

[0061] 2) second stage, when the outer support 2 relative to the ball screw nut 4 moving amount ΔZ still need to increase, its ball screw nut 4 moving amount increases, from ΔH1=5.238mm increases to ΔZ=10mm, the spring sleeve end face against the outer support 2, at this time the motor uses torque control;Servo motor drives screw rotation, screw nut moves down, at this time the pressure of the top 1 to the workpiece is Fn2, ΔZ=10mm;

[0062] Fn2=Fn1+K2*(ΔZ-ΔH1)=3883N

[0063] 3) third stage, when the workpiece needs to continue to increase the clamping force, the moving amount of the outer support 2 screw nut continues to increase, its moving amount ΔZ is greater than 10mm, the servo motor drives the ball screw nut 4 to continue to move down, at this time the clamping force is Fn3;

[0064] From the input motor torque TA=8N*m;i=5, screw pitch L=10mm,

[0065] Fn3=Fn2+(TA*100*2*π*0.90*i)*10 / L=6145N

[0066] When the diameter and modulus of the workpiece to be machined are small, the part itself is weak in rigidity, and the force of the top 1 is too large to deform the workpiece, thereby affecting the machining accuracy of the workpiece, if the required force of the top 1 is 1500N, then 0<1500N<3726N, the first stage control is satisfied, the ball screw nut 4 moves down by a distance of ΔZ=Fn1 / (K1+K2)=1500 / (678+33)=2.110mm, and the ball screw 3 is driven by the servo motor to move the ball screw nut 4 down by a distance of 2.110mm to meet the requirements.

[0067] When the diameter and modulus of the workpiece to be machined are large, the part itself is better in rigidity, and if the required force of the top 1 is 3800N, then 3726N<3800N<3883N, the second stage control is satisfied, the ball screw nut 4 moves down by a distance of ΔZ=(Fn2-Fn1) / K2+ΔH1=(3883-3800) / 33+5.238=7.753mm, and the ball screw 3 is driven by the servo motor to move the ball screw nut 4 down by a distance of 7.753mm to meet the requirements.

[0068] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should be covered in the scope of the claims of the present application.

Claims

1. A gear processing machine tool outer support top pressure adjusting structure, characterized in that: The outer support provided with a top center is arranged on a ball screw driven by a servo motor, a stepped hole is arranged in the outer support, a ball screw nut is arranged in the stepped hole, one end of the ball screw nut is provided with a spring sleeve and a first elastic body, the spring sleeve is fixedly connected with the ball screw nut, the first elastic body is arranged in the spring sleeve, one end of the first elastic body abuts against the end face of the stepped hole, and the other end abuts against the spring sleeve, the other end of the ball screw nut is provided with a second elastic body and a connecting disc, the connecting disc is fixedly connected with the outer support, one end of the second elastic body abuts against the ball screw nut, and the other end abuts against the connecting disc, and the outer support is elastically and floatingly arranged on the ball screw nut through the first elastic body and the second elastic body. The ball screw nut is driven by the servo motor to control the relative distance between the ball screw nut and the workpiece, so that the compression amount of the first elastic body and the second elastic body is changed, and the adjustment of the pressure of the top center is realized, the process of the ball screw nut driving the top center to press the workpiece is divided into three change stages. In the first stage, the change of the pressure of the top center is controlled by the difference between the elastic forces of the first elastic body and the second elastic body in the process that the compression amount of the second elastic body changes from the initial state to zero. In the second stage, the change of the pressure of the top center is controlled by the change of the elastic force of the first elastic body when the compression amount of the second elastic body is zero. In the third stage, the change of the pressure of the top center is controlled by the output of the servo motor when the compression amount of the first elastic body reaches the maximum, that is, the outer support directly abuts against the spring sleeve.

2. The outer support top center pressure adjusting structure of the gear processing machine according to claim 1, characterized in that: A gasket is arranged between the first elastic body and the outer support, and the initial compression amount of the first elastic body is adjusted through the gasket.

3. The outer support top center pressure adjusting structure of the gear processing machine according to claim 1, characterized in that: A stop opening matched with the stepped hole is arranged on the connecting disc, the end face of the stop opening abuts against the second elastic body, and the initial compression amount of the second elastic body is adjusted by changing the depth of the stop opening.

4. The outer support top center pressure adjusting structure of the gear processing machine according to claim 1, characterized in that: The first elastic body and the second elastic body are springs or polyurethane rings.

5. The outer support top center pressure adjusting structure of the gear processing machine according to claim 2, characterized in that: The output mode of the servo motor adopts position loop control and torque control.

6. The outer support top center pressure adjusting structure of the gear processing machine according to claim 2, characterized in that: The elastic modulus of the first elastic body is smaller than that of the second elastic body.

7. The gear processing machine outer support top pressure adjusting structure according to claim 1, characterized in that: In the change process from the first stage to the third stage, the pressure of the top center changes from small to large.

8. The gear processing machine outer support top pressure adjusting structure according to claim 1, characterized in that: In the first stage and the second stage, the servo motor adopts the position loop control mode, and in the third stage, the servo motor adopts the torque control mode.

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