A method for adjusting the pressure of a top center of an outer support of a gear processing machine tool

Abstract

The present application belongs to the technical field of gear machining. It relates to a kind of gear machining machine tool outer support centre pressure adjustment method, adopts gear machining machine tool outer support centre pressure adjustment structure, including the outer support of being equipped with centre, the outer support is equipped on ball screw driven by servo motor, the outer support is equipped with stepped hole, ball screw nut is equipped in stepped hole, one end of ball screw nut is equipped with spring cover and first elastomer, the other end is equipped with second elastomer and connecting disc;The connecting disc is fixedly connected with the outer support, and the second elastomer one end is abutted with ball screw nut, and the other end is abutted with connecting disc;Outer support is elastically floating installation in ball screw nut by first elastomer and second elastomer. The present application drives ball screw nut by servo motor, controls the relative distance of ball screw nut and workpiece, realizes the change adjustment of three stages of centre pressure, reduces the influence of workpiece rigidity on machining accuracy, and the range of workpiece is wider.

Description

Technical Field

[0001] This invention belongs to the field of gear processing technology and relates to a method for adjusting the pressure of the top of the outer support of a gear processing machine tool. Background Technology

[0002] During gear machining on a gear processing machine, an external support center is needed to clamp the gear. Sometimes, due to the small size and poor rigidity of the gear, the clamping force cannot be adjusted, resulting in a fixed clamping force. As the workpiece changes, the required pressure also changes. If the clamping force of the center is too small, it cannot meet the force required to fix the workpiece, causing the workpiece to shift during machining and resulting in substandard machining accuracy. If the clamping force of the center is too large, it exceeds the clamping force required to hold the workpiece, causing deformation of the workpiece or fixture, which also leads to substandard machining accuracy. Therefore, conventional external support structures cannot meet the different clamping force requirements. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to solve the problem that the clamping force of the center needs to be adjusted as needed, and to provide a method for adjusting the pressure of the center of the outer support of a gear processing machine tool.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for adjusting the pressure of the center point on the outer support of a gear processing machine tool is disclosed. The method employs a center point adjustment structure, comprising an outer support on which a center point is mounted. The outer support is mounted on a ball screw driven by a servo motor. The outer 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 outer support, and one end of the second elastic body abuts against the ball screw nut, the other end abutting against the receiving plate. The outer support is elastically floating on the ball screw nut via the first and second elastic bodies.

[0006] By driving the ball screw nut with a servo motor and controlling the relative distance between the ball screw nut and the workpiece, the compression of the first elastic body and the second elastic body can be changed, thereby adjusting the pressure of different centers.

[0007] Furthermore, the process of the ball screw nut driving the center to press down on the workpiece involves three stages of adjustment in the center pressure:

[0008] The first stage is that, during the process of the compression of the second elastomer changing from the initial state to zero, the change of the top pressure is controlled by the elastic force difference between the first elastomer and the second elastomer.

[0009] The second stage is that when the compression of the second elastic body becomes zero, the change in the top pressure is controlled by the change in the elastic force of the first elastic body.

[0010] The third stage is when the compression of the first elastic body reaches its maximum, that is, when the outer support and the spring sleeve directly abut against each other, the change in the pressure at the top is controlled by the output of the servo motor.

[0011] Furthermore, during the transition from the first stage to the third stage, the pressure at the top increased.

[0012] Furthermore, in the first and second stages, the servo motor adopts a position loop control mode; in the third stage, the servo motor adopts a torque control mode.

[0013] Furthermore, by calculating the top pressure curves of the three stages, the stage corresponding to the required clamping force can be selected according to the clamping force required by the workpiece, thereby controlling the movement displacement of the ball screw nut.

[0014] Furthermore, a shim is provided between the first elastomer and the outer support, and the initial compression of the first elastomer is adjusted by the shim.

[0015] Furthermore, the receiving plate is provided with a stop that mates with the stepped hole, and the end face of the stop abuts against the second elastic body. By changing the depth of the stop, the initial compression of the second elastic body can be adjusted.

[0016] Furthermore, the first elastomer and the second elastomer are springs or polyurethane rings.

[0017] Furthermore, the elastic modulus of the first elastomer is less than that of the second elastomer.

[0018] The beneficial effects of this invention are as follows:

[0019] In this invention, the top pressure varies in three stages based on the different compression amounts of the two elastic bodies. During the process of the second elastic body's compression decreasing from its initial state to zero, the change in top pressure is the difference in elastic force between the first and second elastic bodies. When the second elastic body's compression becomes zero, the change in top pressure is the change in the elastic force of the first elastic body. When the first elastic body's compression reaches its maximum, i.e., when the outer support contacts the spring sleeve, the change in top pressure is the change in the output of the servo motor. The top pressure can be adjusted to meet different needs by controlling the first and second elastic bodies and the servo motor, thus overcoming the shortcomings of traditional structures that cannot guarantee machining accuracy due to the inability to adjust the clamping force.

[0020] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram of the method for adjusting the pressure of the top of the outer support of the gear processing machine tool in this invention.

[0023] Figure 2 This is the curve showing the change in the tightening force of the external support.

[0024] Reference numerals in the attached diagram: 1-center; 2-outer support; 3-ball screw; 4-ball screw nut; 5-receiving plate; 6-second elastic body; 7-spring sleeve; 8-first elastic body; 9-washer. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0028] Please see Figures 1-2 This invention relates to a gear processing machine tool external support tip pressure adjustment structure, comprising an external support 2 on which a tip 1 is mounted, the external support 2 being mounted on a ball screw 3 driven by a servo motor, the external support 2 having a stepped hole, a ball screw nut 4 being disposed within the stepped hole, one end of the ball screw nut 4 having a spring sleeve 7 and a first elastic body 8, the spring sleeve 7 being fixedly connected to the ball screw nut 4; the first elastic body 8 being disposed within the spring sleeve 7, one end of the first elastic body 8 abutting against the end face of the stepped hole, and the other end abutting against the spring sleeve 7; the other end of the ball screw nut 4 having a second elastic body 6 and a receiving plate 5; the receiving plate 5 being fixedly connected to the external support 2, one end of the second elastic body 6 abutting against the ball screw nut 4, and the other end abutting against the receiving plate 5; the external support 2 being elastically floated on the ball screw nut 4 via the first elastic body 8 and the second elastic body 6.

[0029] A gasket 9 is provided between the first elastic body 8 and the outer support 2, and the initial compression of the first elastic body 8 can be adjusted by the gasket 9. The receiving plate 5 is provided with a stop that mates with the stepped hole, and the end face of the stop abuts against the second elastic body 6. The initial compression of the second elastic body 6 can be adjusted by changing the depth of the stop.

[0030] In this 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 of a servo motor can be controlled by either position loop control or torque control.

[0032] A method for adjusting the center pressure of an external support of a gear processing machine tool is disclosed. This method employs the aforementioned center pressure adjustment structure of the external support 2 of the gear processing machine tool. By calculating the center pressure curves for three stages, the method selects the stage corresponding to the required clamping force based on the workpiece, thereby controlling the movement displacement of the ball screw nut 4. A servo motor drives the ball screw nut 4, controlling the relative distance between the ball screw nut 4 and the workpiece, thus changing the compression of the first elastic body 8 and the second elastic body, achieving adjustment of the center pressure at different levels.

[0033] The process of ball screw nut 4 driving center 1 to press down on the workpiece involves three stages of pressure adjustment at center 1:

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

[0035] The second stage is that when the compression of the second elastic body 6 becomes zero, the pressure change of the tip 1 is controlled by the elastic force change of the first elastic body 8.

[0036] The third stage is when the compression of the first elastic body 8 reaches its maximum, that is, when the outer support 2 and the spring sleeve 7 directly abut against each other, the change in pressure of the tip 1 is controlled by the output of the servo motor.

[0037] During the transition from the first to the third stage, the pressure at the tip increases. In the first and second stages, the servo motor uses a position loop control mode; in the third stage, the servo motor uses a torque control mode.

[0038] The following are specific implementation examples:

[0039] Servo motor torque: T = 8 Nm, reducer transmission ratio i = 5, ball screw 3 diameter and pitch 50*10; outer bracket 2 weight G = 300 kg; selected cylindrical helical compression spring specifications: 8*65*110, K2 = 33 N / mm, selected polyurethane ring of grade 8270, elastic modulus E' = 60 kgf / cm² (from table). 2 Polyurethane spring pad dimensions: Inner diameter d = 65 * Outer diameter D = 90 * Free height H01 = 35.

[0040] FA=(TA*2*π*η*i) / L

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

[0042] Calculation of polyurethane ring elasticity:

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

[0044] Elastic modulus E = c * E' = 78 kgf / cm 2 ;

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

[0046] Calculation of elastic force of external support 2 under static equilibrium state:

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

[0048] H 01 =35mm;

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

[0050] H 02 =110mm;

[0051] K2 = 33 N / mm (from 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)=29.76mm;

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

[0057] The outer support 2 and ball screw nut 4 descend, and the pressure of the tip 1 is controlled.

[0058] 1) In the first stage, after the center 1 of the outer support 2 presses against the workpiece, let the pressure of the center 1 of the outer support 2 on the workpiece be Fn1, and the movement of the outer support 2 relative to the ball screw nut 4 be ΔZ. At this time, the servo motor uses position loop control, and the clamping force of the outer support 2 is:

[0059] Fn1=(K1+K2)*ΔZ=3726N

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

[0061] 2) In the second stage, when the movement ΔZ of the outer support 2 relative to the ball screw nut 4 needs to be increased, the downward movement of the ball screw nut 4 increases from ΔH1=5.238mm to ΔZ=10mm. During this process, the end face of the spring sleeve presses against the outer support 2. At this time, the motor adopts torque control; the servo motor drives the screw to rotate, and the screw nut moves downward. At this time, the pressure of the center 1 on the workpiece is Fn2, ΔZ=10mm.

[0062] Fn2=Fn1+K2*(ΔZ-ΔH1)=3883N

[0063] 3) In the third stage, when the clamping force of the workpiece needs to be increased, the movement of the screw nut of the outer support 2 continues to increase. When the movement ΔZ is greater than 10mm, the servo motor drives the ball screw nut 4 to continue to move downward. At this time, the clamping force is Fn3.

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

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

[0066] When the diameter and module of the workpiece being machined are small, the rigidity of the part itself is weak. If the center force is too large, the workpiece will deform, thus affecting the machining accuracy of the workpiece. If the required center force is 1500N, then when 0 < 1500N < 3726N, the first stage of control is satisfied. The distance the ball screw nut 4 descends is ΔZ = Fn1 / (K1+K2) = 1500 / (678+33) = 2.110mm. By controlling the servo motor to drive the ball screw 3, the ball screw nut 4 can be moved down a distance of 2.110mm to meet the requirements.

[0067] When the workpiece diameter and module are large, the rigidity of the part itself is good. If the required center force is 3800N, then 3726N < 3800N < 3883N, which meets the second stage control. The descent distance of the ball screw nut 4 is ΔZ = (Fn2 - Fn1) / K2 + ΔH1 = (3883 - 3800) / 33 + 5.238 = 7.753mm. By controlling the servo motor to drive the ball screw 3, the ball screw nut 4 can be moved down a distance of 7.753mm to meet the requirements.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for adjusting the center pressure of an external support of a gear processing machine tool, characterized in that: A gear processing machine tool external support tip pressure adjustment structure is adopted. This structure includes an external support on which a tip 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, with the spring sleeve fixedly connected to the ball screw nut. The first elastic body is disposed within the spring sleeve, with one end abutting against the end face of the stepped hole and the other end abutting 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. By driving the ball screw nut with a servo motor, the relative distance between the ball screw nut and the workpiece is controlled, thereby changing the compression of the first elastic body and the second elastic body, and adjusting the pressure of different centers. The process of the ball screw nut driving the center to press down on the workpiece involves three stages of adjustment of the center pressure: The first stage is that, during the process of the compression of the second elastomer changing from the initial state to zero, the change of the top pressure is controlled by the elastic force difference between the first elastomer and the second elastomer. The second stage is that when the compression of the second elastic body becomes zero, the change in the top pressure is controlled by the change in the elastic force of the first elastic body. The third stage is when the compression of the first elastic body reaches its maximum, that is, when the outer support and the spring sleeve directly abut against each other, the change in the pressure of the top is controlled by the output of the servo motor. During the transition from the first stage to the third stage, the top pressure increases. In the first and second stages, the servo motor uses a position loop control mode. In the third stage, the servo motor uses a torque control mode. By calculating the top pressure curves for the three stages, the stage corresponding to the required clamping force can be selected based on the workpiece's required clamping force, thereby controlling the movement displacement of the ball screw nut.

2. The method for adjusting the center pressure of the outer support of a gear processing machine tool according to claim 1, characterized in that: A gasket is provided between the first elastomer and the outer support, and the initial compression of the first elastomer is adjusted by the gasket.

3. The method for adjusting the center pressure of the outer support of a gear processing machine tool according to claim 1, characterized in that: The receiving plate is provided with a stop that mates with the stepped hole. The end face of the stop abuts against the second elastic body. By changing the depth of the stop, the initial compression of the second elastic body can be adjusted.

4. The method for adjusting the center pressure of the outer support of a gear processing machine tool according to claim 1, characterized in that: The first and second elastomers are springs or polyurethane rings.

5. The method for adjusting the center pressure of the outer support of a gear processing machine tool according to claim 1, characterized in that: The elastic modulus of the first elastomer is less than that of the second elastomer.

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