Online dressing method for grinding wheel and lead screw machining device

Abstract

The invention relates to the technical field of high-precision planetary roller lead screw machining, in particular to an online dressing method of a grinding wheel and a lead screw machining device. The dressing method comprises the step of reversely deducing the abrasion loss of a grinding wheel according to the pitch diameter change of a lead screw sample piece, and comprises the steps that the pitch diameter D1 of the lead screw sample piece is detected in real time, and when the pitch diameter error value delta D of the D1 and the reference pitch diameter D2 of the lead screw sample piece exceeds a preset pitch diameter error threshold value, delta Rmax = (delta D * tan theta) / 2 is met; wherein delta Rmax is the maximum radius of the grinding wheel; d (X) = d0 + eta * (delta Rmax-delta R (X)); wherein d (X) is the dressing depth of the dressing grinding wheel to each position in the axial direction of the grinding wheel. According to the online dressing method for the grinding wheel and the lead screw machining device, the problem that a traditional online dressing method for the grinding wheel cannot dynamically adapt to the abrasion gradient of the grinding wheel, and consequently over-dressing / under-dressing is caused is solved.

Description

Technical Field

[0001] The present application relates to the technical field of high-precision planetary roller screw processing, and in particular to an online dressing method for a grinding wheel and a screw processing device. Background Art

[0002] The processing accuracy of thin-walled deep-hole planetary roller screws used in military or humanoid robots is extremely high, and must be controlled within ±1μm at least.

[0003] The existing thin-walled deep-hole planetary roller screw is processed by a grinding wheel. During the processing, the grinding wheel is dressed in real time by a dressing wheel. However, the traditional online dressing method of the grinding wheel has the following problems:

[0004] The traditional online dressing method for grinding wheels has a rough control quantity and relies on fixed parameter dressing. It cannot dynamically adapt to the wear gradient of the grinding wheel, resulting in over-dressing / under-dressing. Summary of the Invention

[0005] The purpose of this application is to provide an online dressing method for a grinding wheel and a screw processing device, thereby solving the problem of the traditional online dressing method of a grinding wheel having a rough control amount, relying on fixed parameter dressing, and being unable to dynamically adapt to the wear gradient of the grinding wheel, resulting in over-dressing / under-dressing.

[0006] According to a first aspect of the present application, there is provided an online dressing method for a grinding wheel, wherein the grinding wheel is used to process a lead screw sample, and the grinding wheel can be dressed by a dressing wheel while processing the lead screw sample;

[0007] The online dressing method of the grinding wheel comprises:

[0008] Inversely inferring the wear amount of the grinding wheel according to the change in the pitch diameter of the lead screw sample;

[0009] The step of inferring the wear amount of the grinding wheel according to the change of the pitch diameter of the screw sample comprises:

[0010] The middle diameter D1 of the screw sample is detected in real time. When the middle diameter error value ΔD between D1 and the reference middle diameter D2 of the screw sample exceeds a predetermined middle diameter error threshold, the following conditions are satisfied:

[0011] ΔR max =(ΔD×tanθ) / 2; where ΔR max is the maximum radius of the grinding wheel, ΔD is the pitch diameter error of the screw sample, and θ is the reference thread profile angle of the screw sample;

[0012] d (X) =d0+η×(ΔR max -ΔR(X) ), where d (X) is the dressing depth of the dressing wheel at each axial position of the grinding wheel, d0 is the reference dressing depth of the dressing wheel, η is the gradient compensation coefficient, ΔR (X) is the radius of the grinding wheel at various axial positions.

[0013] In any of the above technical solutions, further, the step of inferring the wear amount of the grinding wheel according to the change in the middle diameter of the screw sample also includes: based on the physical mechanism of the wear of the grinding wheel during the grinding process, calculating the evolution of the radius of each axial position of the grinding wheel with space and time by using a component differential equation;

[0014] Among them, F n(x，t) is the normal grinding force, V (x，t) is the linear speed of the grinding wheel, k p is the wear rate coefficient of the grinding wheel.

[0015] In any of the above technical solutions, further, the online dressing method for the grinding wheel further includes: compensating the wear of the grinding wheel once according to the material of the grinding wheel; the step of compensating the wear of the grinding wheel once according to the material of the grinding wheel includes:

[0016] Δd error =β×(G / G0)×(B / B0)^γ;

[0017] Where Δd error To compensate for the wear of the grinding wheel at one time, G is the actual particle size of the grinding wheel, G0 is the reference particle size of the grinding wheel, B is the bond hardness of the grinding wheel, B0 is the reference hardness of the grinding wheel, β and γ are the material property correction coefficients of the grinding wheel;

[0018] Then, the total dressing depth d of the dressing wheel is 总 =d (X) +Δd error .

[0019] In any of the above technical solutions, the online dressing method for the grinding wheel further includes: adjusting the dressing speed of the dressing wheel; the step of adjusting the dressing speed of the dressing wheel includes:

[0020] Real-time detection of the actual radial dressing force F of the dressing wheel real , when F real Exceeding target radial dressing force F target When the target radial dressing force threshold is met,

[0021] Vnew =V old ×(F target / F real )^k; where V new is the adjusted dressing speed of the dressing wheel, V old The dressing speed of the dressing grinding wheel before adjustment, F target is the target radial dressing force of the dressing wheel, F real The actual radial dressing force of the dressing wheel, k is the material damping coefficient of the grinding wheel.

[0022] In any of the above technical solutions, the online dressing method for the grinding wheel further includes: secondarily compensating the wear of the grinding wheel according to the fluctuation of the dressing force; the step of secondarily compensating the wear of the grinding wheel according to the fluctuation of the dressing force includes:

[0023] Δd=[α×(F real -F target )]-Δd error ;

[0024] Wherein, Δd is the wear of the grinding wheel compensated by the secondary method, and α is the dressing force displacement conversion coefficient; then, the total dressing depth d of the dressing wheel is 总 =d (X) +Δd.

[0025] According to the second aspect of the present application, a screw processing device is provided, which includes a grinding wheel, a dressing wheel and a screw sample; the grinding wheel is used to process the screw sample, and the grinding wheel can be dressed by the dressing wheel while processing the screw sample; the dressing wheel uses the online dressing method of the grinding wheel as described above.

[0026] In any of the above technical solutions, further, the screw processing device also includes a screw middle diameter measuring instrument; the screw middle diameter measuring instrument detects the middle diameter D1 of the screw sample in real time.

[0027] In any of the above technical solutions, further, the screw processing device further includes a plurality of force sensors; the plurality of force sensors are spaced apart along the outer edge of one side of the dressing wheel, the radial dressing force of the dressing wheel detected in real time by the plurality of force sensors, and the average value of the plurality of radial dressing forces detected in real time by the plurality of force sensors is the actual radial dressing force F (real) .

[0028] In any of the above technical solutions, further, the screw processing device also includes a first slide and a second slide; the first slide can drive the dressing wheel to move along the radial direction of the grinding wheel, and the second slide can drive the dressing wheel to move along the axial direction of the grinding wheel to dress the grinding wheel.

[0029] In any of the above technical solutions, further, the screw processing device further includes a numerical control system; the numerical control system receives the data sent by the force sensor and the screw diameter measuring instrument, and calculates the screw diameter according to ΔR max =(ΔD×tanθ) / 2, d (X) =d0+η×(ΔR max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error ; Calculate the total dressing depth d at each axial position of the dressing wheel 总 =d (X) +Δd, the numerical control system is based on the total dressing depth d at each axial position of the dressing wheel 总 controlling the first slide and the second slide to dress the grinding wheel;

[0030] During the trimming process, if the CNC system determines that F real Exceeding target radial dressing force F target The target radial trimming force threshold is based on V new =V old ×(F target / F real )^k calculates the adjusted dressing speed V of the dressing grinding wheel new , the numerical control system adjusts the dressing speed V new Control the speed of the dressing wheel to V new .

[0031] The online dressing method of the grinding wheel of the present application includes:

[0032] The wear of the grinding wheel is inferred based on the change in the pitch diameter of the screw sample. That is, the pitch diameter D1 of the screw sample is detected in real time. When the pitch diameter error value ΔD between D1 and the reference pitch diameter D2 of the screw sample exceeds the predetermined pitch diameter error threshold, the following conditions are met:

[0033] ΔR max =(ΔD×tanθ) / 2; where ΔR maxis the maximum radius of the grinding wheel, ΔD is the mean diameter error of the screw sample, and θ is the reference thread profile angle of the screw sample;

[0034] d (X) =d0+η×(ΔR max -ΔR (X) ), where d (X) is the dressing depth of the grinding wheel at each position on the axial direction of the grinding wheel, d0 is the reference dressing depth of the grinding wheel, η is the gradient compensation coefficient, ΔR (X) is the radius of the grinding wheel at various axial positions.

[0035] According to the above technical features, the beneficial effects of this application are:

[0036] This application uses the mid-diameter of the screw sample to reversely infer the amount of grinding wheel wear and dynamically correct the dressing depth without stopping the machine. That is, first, according to ΔR max =(ΔD×tanθ) / 2Calculate the maximum radius ΔR of the grinding wheel when the diameter error of the screw sample is too large max .

[0037] Then, according to ΔR max -ΔR (X) Calculate the wear amount at each axial position of the grinding wheel.

[0038] Finally, according to d (X) =d0+η×(ΔR max -ΔR (X) ) Calculate the dressing depth d of the dressing wheel at each axial position of the grinding wheel (X) .

[0039] As mentioned above, the present application reversely estimates the amount of grinding wheel wear through the mean diameter of the screw sample, and dynamically allocates the non-stop dressing depth according to the wear gradient to avoid over-dressing / under-dressing, adapt to complex grinding wheel wear, and ensure the consistency of the profile throughout the entire stroke.

[0040] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0042] Figure 1A schematic diagram showing the overall structure of a lead screw processing device according to an embodiment of the present application is shown;

[0043] Figure 2 Show Figure 1 Schematic diagram of part of the structure;

[0044] Figure 3 Show Figure 2 Schematic diagram of part of the structure;

[0045] Figure 4 A schematic diagram showing the assembly structure of a dressing electric spindle and a dressing grinding wheel according to an embodiment of the present application is shown;

[0046] Figure 5 A schematic diagram of the assembly structure of the grinding electric spindle and the grinding wheel according to an embodiment of the present application is shown.

[0047] Icons: 110-dressing electric spindle; 120-dressing grinding wheel; 210-grinding electric spindle; 220-grinding wheel; 310-first slide; 320-second slide; 400-force sensor; 500-screw diameter measuring instrument; 600-turntable; 700-turntable connecting plate; 800-guide rail; 900-screw sample. DETAILED DESCRIPTION

[0048] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent upon understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein. Rather, except for operations that must occur in a particular order, changes may be made that will be apparent upon understanding the disclosure of this application. Furthermore, descriptions of features known in the art may be omitted for clarity and brevity.

[0049] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways to implement the methods, devices, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0050] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, it may be directly “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on,” “directly connected to,” “directly coupled to,” “directly over,” or “directly covering” another element, there may be no other elements intervening therebetween.

[0051] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0052] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are used only to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, a first member, component, region, layer, or portion in the examples described herein may also be referred to as a second member, component, region, layer, or portion without departing from the teachings of the examples.

[0053] For ease of description, spatial relational terms such as "above," "upper," "below," and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element would subsequently be "below" or "lower" relative to the other element. Thus, the term "above" includes both the orientations "above" and "below," depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0054] The terms used herein are intended only to describe various examples and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular is intended to include the plural. The terms "comprise," "include," and "have" list the presence of stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0055] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include changes in shapes that occur during manufacturing.

[0056] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0057] Before the present application was proposed, the traditional online dressing method for grinding wheels had a rough control quantity and relied on fixed parameter dressing, which could not dynamically adapt to the wear gradient of the grinding wheel, resulting in over-dressing / under-dressing.

[0058] In view of this, the first aspect of the present application provides an online dressing method for a grinding wheel, thereby solving the problem that the traditional online dressing method for a grinding wheel has rough control, relies on fixed parameter dressing, cannot dynamically adapt to the wear gradient of the grinding wheel, and leads to over-dressing / under-dressing.

[0059] The following is a detailed description of the screw processing device of the present application, as well as the online dressing method of the grinding wheel followed by the screw processing device during the processing of the screw sample. The screw processing device of the present application includes a grinding wheel, a dressing wheel and a screw sample. Among them, the grinding wheel is used to process the screw sample, and the grinding wheel can be dressed by the dressing wheel while processing the screw sample. The online dressing method of the grinding wheel of the present application can avoid over-dressing / under-dressing during the dressing process of the grinding wheel, adapt to complex grinding wheel wear, and ensure the consistency of the profile of the entire stroke.

[0060] The online dressing method of the grinding wheel of the present application includes:

[0061] The wear of the grinding wheel is inferred based on the change in the pitch diameter of the screw sample. That is, the pitch diameter D1 of the screw sample is detected in real time. When the pitch diameter error value ΔD between D1 and the reference pitch diameter D2 of the screw sample exceeds the predetermined pitch diameter error threshold, the following conditions are met:

[0062] ΔR max =(ΔD×tanθ) / 2; where ΔR maxis the maximum radius of the grinding wheel, ΔD is the mean diameter error of the screw sample, and θ is the reference thread profile angle of the screw sample;

[0063] d (X) =d0+η×(ΔR max -ΔR (X) ), where d (X) is the dressing depth of the grinding wheel at each position on the axial direction of the grinding wheel, d0 is the reference dressing depth of the grinding wheel, η is the gradient compensation coefficient, ΔR (X) is the radius of the grinding wheel at various axial positions.

[0064] It should be noted here that the reference mean diameter D2 can be understood as the target mean diameter to be processed by the screw sample. Similarly, θ can be understood as the target thread profile angle to be processed by the screw sample; d0 can be understood as the initial fixed standard finishing depth designed based on the target to be processed by the screw sample.

[0065] That is:

[0066] This application uses the mid-diameter of the screw sample to reversely infer the amount of grinding wheel wear and dynamically correct the dressing depth without stopping the machine. That is, first, according to ΔR max =(ΔD×tanθ) / 2Calculate the maximum radius ΔR of the grinding wheel when the diameter error of the screw sample is too large max .

[0067] Then, according to ΔR max -ΔR (X) Calculate the wear amount at each axial position of the grinding wheel.

[0068] Finally, according to d (X) =d0+η×(ΔR max -ΔR (X) ) Calculate the dressing depth d of the dressing wheel at each axial position of the grinding wheel (X) .

[0069] As mentioned above, the present application reversely estimates the amount of grinding wheel wear through the mean diameter of the screw sample, and dynamically allocates the non-stop dressing depth according to the wear gradient to avoid over-dressing / under-dressing, adapt to complex grinding wheel wear, and ensure the consistency of the profile throughout the entire stroke.

[0070] It should be noted here that the gradient compensation coefficient η is taken as follows:

[0071] When the grinding wheel is a conventional grinding wheel (WA60K), η = 0.4-0.6. When the grinding wheel is a CBN grinding wheel (B151), η = 0.25-0.35. When the grinding wheel is a diamond grinding wheel (SD3000), η = 0.15-0.25.

[0072] When ΔR (X) →ΔR max When d (X) →d0 (reference trimming depth); when ΔR (X) →0, d (X) ≤1.2d0 (safety threshold).

[0073] Process validation indicators:

[0074] The radial runout of the grinding wheel after dressing is ≤1μm; the surface roughness of the grinding workpiece is R a ≤0.4μm; grinding wheel life increased by ≥20% (compared to the fixed compensation in the existing technology).

[0075] Optionally, in an embodiment of the present application, the step of inferring the wear amount of the grinding wheel according to the change in the pitch diameter of the lead screw sample further includes:

[0076] Based on the physical mechanism of grinding wheel wear during the grinding process (abrasive shedding, binder wear, clogging, etc.), the component differential equation calculates the evolution of the radius of each axial position of the grinding wheel with space and time. The details are as follows:

[0077] Among them, F n(x，t) is the normal grinding force (N), which is positively correlated with the material removal rate. (x，t) is the linear speed of the grinding wheel (m / s), k p is the wear rate coefficient of the grinding wheel (related to the hardness and abrasive properties of the grinding wheel). It can be concluded that the radius ΔR at each position of the grinding wheel axial direction (X) , and then according to d (X) =d0+η×(ΔR max -ΔR (X) ) Calculate the dressing depth d of the dressing wheel at each axial position of the grinding wheel (X) .

[0078] It should be noted here that the wear rate coefficient k of the grinding wheel p The values ​​are as follows:

[0079] Grinding wheel type Screw sample material <![CDATA[k p Range (×10 -8 mm / (N·m / s))]]> Alumina grinding wheel (WA60) 45# steel 3.2-5.6 CBN grinding wheel (B151) Titanium alloy TC4 0.8-1.5 Diamond grinding wheel (SD3000) <![CDATA[Ceramic Al2O3]]> 0.2-0.4

[0080] It is also worth mentioning that in the traditional online dressing method of grinding wheels, the dressing amount adjustment is only based on the grinding wheel profile model, ignoring the influence of the grinding wheel material properties (such as binder hardness and particle size distribution).

[0081] In view of this, in order to solve the above technical problems, in an embodiment of the present application, the online dressing method for the grinding wheel further includes a step of compensating the wear of the grinding wheel according to the material of the grinding wheel, that is, adjusting according to the empirical formula of the material of the grinding wheel, which is as follows:

[0082] Trim amount deviation prediction model: Δd error =β×(G / G0)×(B / B0)^γ; where, Δd error To compensate for the wear of the grinding wheel at one time, G is the actual particle size of the grinding wheel, G0 is the reference particle size of the grinding wheel, B is the bond hardness of the grinding wheel, B0 is the reference hardness of the grinding wheel, and β and γ are the material property correction coefficients of the grinding wheel.

[0083] Then, the total dressing depth d of the dressing wheel 总 =d (X) +Δd error .

[0084] It should be noted here that the material property correction coefficients β and γ of the grinding wheel are as follows:

[0085] Grinding wheel type Binder type Particle size range β range gamma range Alumina grinding wheel (WA) Vitrified bond 60-120# 0.8-1.2 1.3-1.6 CBN grinding wheel Metal binder 120-400# 1.5-2.0 0.9-1.2 diamond grinding wheel Resin bond 200-2000# 0.6-0.9 1.8-2.4

[0086] It should be noted here that G (actual granularity):

[0087] Definition: The actual abrasive size of the grinding wheel (usually expressed in "mesh" or "#", such as 60#, 120#), which represents the coarseness of the abrasive.

[0088] Function: Directly affects the cutting ability, surface roughness and material removal rate of the grinding wheel. The larger the grit size (the higher the value), the finer the abrasive grains, the more cutting edges, and the higher the surface processing quality, but the cutting efficiency may decrease.

[0089] G0 (base particle size):

[0090] Definition: The theoretical reference grit size for grinding wheel design, usually based on the factory nominal value of the grinding wheel or the optimal grit size under ideal working conditions.

[0091] Function: Serves as a benchmark value for the compensation model, used to quantify the deviation between the actual particle size and the design target.

[0092] The meaning of the ratio G / G0:

[0093] Standardized compensation factor: The ratio of actual particle size to reference particle size is used to standardize the effect of particle size changes on the compensation amount, eliminating differences between different grinding wheel models or batches.

[0094] Physical mechanism:

[0095] G>G0 (actual abrasive grains are finer): This may cause the cutting ability of the grinding wheel to decrease, and the dressing effect needs to be maintained by increasing the compensation amount (Δd).

[0096] G < G0 (actual abrasive grains are coarser): Cutting ability is enhanced, and the compensation amount may be reduced to avoid over-trimming. Further, in the embodiments of the present application, the on-line dressing method of the grinding wheel further includes adjusting the dressing speed of the dressing wheel, specifically as follows:

[0097] Real-time detection of the actual radial dressing force F of the dressing wheel real , when F real exceeds the target radial dressing force F target of the target radial dressing force threshold F min or F max , then it satisfies:

[0098] V new = V old ×(F target / F real )^k;

[0099] Where, V new is the adjusted dressing speed of the dressing wheel, V old is the dressing speed of the dressing wheel before adjustment, F target is the target radial dressing force of the dressing wheel, F real is the actual radial dressing force of the dressing wheel, and k is the material damping coefficient of the grinding wheel. It should be noted here that the target radial dressing force F target can be understood as the initial fixed standard radial dressing force designed based on the target to be processed by the lead screw sample.

[0100] By setting like this, the V real can be adjusted in real time according to the actual radial dressing force F new of the dressing wheel to prevent the dressing wheel from rotating too fast and causing equipment danger.

[0101] It should be noted here that the value of the material damping coefficient k of the grinding wheel is as follows:

[0102]

[0103] Further, in the embodiments of the present application, the on-line dressing method of the grinding wheel further includes adjusting the dressing parameters in real time based on the dressing force fluctuation, performing secondary compensation on the wear amount of the grinding wheel, and then performing secondary compensation on the dressing amount. Specifically as follows:

[0104] Δd = [α×(F real -F target )]-Δd error ; where, Δd is the wear amount of the secondary compensation grinding wheel, and α is the dressing force displacement conversion coefficient. Then, the total dressing depth d 总 = d (X) +Δd.

[0105] It should be noted here that the value of the dressing force displacement conversion coefficient α is as follows:

[0106] Grinding wheel type Binder type Particle size range α range (μm / N) Alumina grinding wheel (WA) Vitrified bond 60-120# 0.08-0.15 CBN grinding wheel Metal binder 120-400# 0.05-0.12 diamond grinding wheel Resin bond 200-3000# 0.12-0.25 Electroplated CBN grinding wheel Electroplating binder D126-D251 0.03-0.08

[0107] In summary, the online dressing method for the grinding wheel of the present application includes:

[0108] According to ΔR max =(ΔD×tanθ) / 2, d (X) =d0+η×(ΔR max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error ; Calculate the total dressing depth d at each axial position of the dressing wheel 总 =d (X) +Δd.

[0109] During the trimming process, if the CNC system determines that F real Exceeding target radial dressing force F target The target radial trimming force threshold is based on V new =V old ×(F target / F real )^k calculates the dressing speed V after the dressing wheel is adjusted new , and then according to the adjusted trimming speed V new Control the speed of the dressing wheel to V new .

[0110] According to a second aspect of the present application, a screw processing device is provided, comprising a grinding wheel 220, a dressing wheel 120, and a screw sample 900. The grinding wheel 220 is used to process the screw sample 900. While the grinding wheel 220 processes the screw sample 900, it can be dressed by the dressing wheel 120. The dressing wheel 120 dresses the grinding wheel 220 using the above-described online dressing method for a grinding wheel.

[0111] Specifically, the assembly relationship of the screw processing device of the present application is as follows:

[0112] like Figures 1 to 5As shown, the screw processing device of the present application can be removably mounted on an external thread grinder. The screw processing device includes a turntable 600 that is removably fixedly connected to the guide rail of the grinder and can rotate about the A-axis. The central axis of the turntable 600 is ensured to be at the same height as the central axis of the thin-walled deep-hole planetary roller screw. A turntable connecting plate 700 is fixedly connected to the turntable 600, which can be rotated and adjusted about the A-axis. The turntable connecting plate 700 is provided with a removable dressing electric spindle drive mechanism and a grinding electric spindle 210. A dressing electric spindle 110 and a dressing grinding wheel 120 are provided on the dressing electric spindle drive mechanism, and the dressing electric spindle drive mechanism includes a first slide 310 and a second slide 320 connected to each other; wherein, the first slide 310 can drive the dressing electric spindle 110 and the dressing grinding wheel 120 to move along the radial direction of the grinding wheel 220, and the second slide 320 can drive the dressing electric spindle 110 and the dressing grinding wheel 120 to move along the axial direction of the grinding wheel 220 to dress the grinding wheel 220.

[0113] In addition, if Figure 2 and Figure 4 As shown, six uniformly distributed force sensors 400 are provided on the dressing wheel 120 (six uniformly distributed force sensors 400 are installed on Figure 4 The six force sensors 400 are spaced apart along the outer edge of one side of the dressing wheel 120. The six force sensors 400 detect the radial dressing force of the dressing wheel 120 in real time. The average value of the multiple radial dressing forces detected in real time by the six force sensors 400 is the actual radial dressing force F. real .

[0114] like Figure 2 As described above, the grinding electric spindle 210 is provided with a grinding wheel 220 and a screw pitch diameter measuring instrument 500 , and the screw pitch diameter measuring instrument 500 detects the pitch diameter D1 of the screw sample 900 in real time.

[0115] The axes of the grinding wheel 220, the turntable 600 and the lead screw sample 900 are at the same height. All components of the lead screw processing device are jointly fed and retracted in the radial direction of the lead screw sample 900. Figure 1 As shown, the guide rail 800 provided at the bottom of the platform is slidably connected to the guide rail of the external thread grinder, and the guide rail 800 is used to perform feed and retract motion in the radial direction of the lead screw sample 900.

[0116] The grinding wheel dressing process is as follows:

[0117] The screw processing device of the present application also includes a numerical control system. The screw processing device of the present application uses an integrated numerical control system to perform fully closed-loop automatic control of the grinding wheel dressing process. The numerical control system controls the dressing electric spindle drive mechanism to drive the dressing electric spindle and the dressing grinding wheel to perform curved dressing motion along the radial and axial directions of the grinding wheel.

[0118] First, the CNC system receives the data sent by the force sensor and the screw diameter measuring instrument, and calculates the value of the force sensor according to the ΔR max =(ΔD×tanθ) / 2, d (X) =d0+η×(ΔR max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error Calculate the total dressing depth d at each axial position of the dressing wheel 总 =d (X) +Δd.

[0119] Then, the CNC system adjusts the total dressing depth d at each axial position of the dressing wheel. 总 The first slide 310 and the second slide 320 are controlled to dress the grinding wheel.

[0120] During the trimming process, if the CNC system determines that F real Exceeding target radial dressing force F target The target radial trimming force threshold is based on V new =V old ×(F target / F real )^k calculates the dressing speed V after the dressing wheel is adjusted new , the CNC system adjusts the dressing speed V new Control the speed of the dressing wheel to V new .

[0121] To summarize, the present application provides an online dressing method for the grinding wheel of a screw processing device, which reversely infers the wear of the grinding wheel through the middle diameter of the screw sample, and dynamically allocates the dressing depth for non-stop correction according to the wear gradient, thereby avoiding over-dressing / under-dressing, adapting to complex grinding wheel wear, and ensuring the consistency of the full-stroke profile.

[0122] This application is directed to an online dressing method for the grinding wheel of a screw processing device. The above-mentioned means are combined to ensure ultra-high precision radial runout control of less than 1 micron during processing of the screw sample. The dressing method based on force-mid-diameter dual closed-loop control is suitable for ultra-precision processing tasks and ensures the accuracy of ultra-precision grinding of the screw sample.

[0123] In addition, traditional online dressing methods for grinding wheels mostly rely on vision and acoustics (such as patent CN118905946B), but have the following limitations: visual sensors are easily contaminated by grinding fluid, require frequent maintenance, and are limited by optical resolution (±5μm); acoustic sensors such as AE sensors commonly used in electric spindles are often limited in acoustic accuracy and are less suitable for scenarios such as tool collision prediction.

[0124] This application is about an online dressing method for the grinding wheel of a screw processing device. By using a force sensor (directly monitoring the dressing status) + a screw middle diameter measuring instrument (indirect feedback of grinding wheel wear), it breaks through the accuracy limitations of a single sensor, significantly improves the accuracy, and has strong resistance to environmental interference.

[0125] This application aims to quantify the material properties of an online dressing method for a grinding wheel of a screw processing device: for the first time, the grinding wheel grain size and binder composition are incorporated into a dressing amount prediction model to improve the accuracy of micro-displacement compensation.

[0126] This application is directed to a gradient dressing algorithm for an online dressing method of a grinding wheel of a screw processing device: in view of the uneven axial wear of the grinding wheel, dynamic distribution of dressing depth is achieved, the profile consistency of the entire stroke is ensured, and the accuracy problem is solved.

[0127] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that any technician familiar with this technical field can still modify the technical solutions recorded in the aforementioned embodiments within the technical scope disclosed in the present application, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be covered by the scope of protection of the present application.

Claims

1. An online dressing method for a grinding wheel, characterized in that: The grinding wheel is used to process the lead screw sample, and the grinding wheel can be dressed by the dressing wheel while processing the lead screw sample; The online dressing method of the grinding wheel comprises: Inversely inferring the wear amount of the grinding wheel according to the change in the pitch diameter of the lead screw sample; The step of inferring the wear amount of the grinding wheel according to the change of the pitch diameter of the screw sample comprises: The middle diameter D1 of the screw sample is detected in real time. When the middle diameter error value ΔD between D1 and the reference middle diameter D2 of the screw sample exceeds a predetermined middle diameter error threshold, the following conditions are satisfied: ΔR max =(ΔD×tanθ) / 2; Where, ΔR max is the maximum radius of the grinding wheel, ΔD is the pitch diameter error of the screw sample, and θ is the reference thread profile angle of the screw sample; d (X) =d0+η×(ΔR max -ΔR (X) ); Among them, d (X) is the dressing depth of the dressing wheel at each axial position of the grinding wheel, d0 is the reference dressing depth of the dressing wheel, η is the gradient compensation coefficient, ΔR (X) is the radius of the grinding wheel at various axial positions.

2. The online dressing method for a grinding wheel according to claim 1, characterized in that: The step of inferring the wear amount of the grinding wheel according to the change of the pitch diameter of the screw sample also includes: Based on the physical mechanism of the grinding wheel wear during the grinding process, the component differential equation calculates the evolution of the radius of each axial position of the grinding wheel with space and time; Among them, F n(x，t) is the normal grinding force, V (x，t) is the linear speed of the grinding wheel, k p is the wear rate coefficient of the grinding wheel.

3. The online dressing method for a grinding wheel according to claim 2, characterized in that: The online dressing method of the grinding wheel also includes: Compensating for the wear of the grinding wheel once according to the material of the grinding wheel; The step of compensating the wear amount of the grinding wheel once according to the material of the grinding wheel comprises: Δd error =β×(G / G0)×(B / B0)^γ; Where Δd error To compensate for the wear of the grinding wheel at one time, G is the actual particle size of the grinding wheel, G0 is the reference particle size of the grinding wheel, B is the bond hardness of the grinding wheel, B0 is the reference hardness of the grinding wheel, β and γ are the material property correction coefficients of the grinding wheel; Then, the total dressing depth d of the dressing wheel is 总 =d (X) +Δd error .

4. The online dressing method for a grinding wheel according to claim 3, characterized in that: The online dressing method of the grinding wheel also includes: Adjusting the dressing speed of the dressing grinding wheel; The step of adjusting the dressing speed of the dressing grinding wheel comprises: Real-time detection of the actual radial dressing force F of the dressing wheel real , when F real Exceeding target radial dressing force F target When the target radial dressing force threshold is met, V new =V old ×(F target / F real )^k; Among them, V new is the adjusted dressing speed of the dressing wheel, V old The dressing speed of the dressing grinding wheel before adjustment, F target is the target radial dressing force of the dressing wheel, F real The actual radial dressing force of the dressing wheel, k is the material damping coefficient of the grinding wheel.

5. The online dressing method for a grinding wheel according to claim 4, characterized in that: The online dressing method of the grinding wheel also includes: Secondarily compensating for the wear of the grinding wheel according to the fluctuation of the dressing force; The step of secondary compensating the wear of the grinding wheel according to the dressing force fluctuation comprises: Δd=[α×(F real -F target )]-Δd error ; Wherein, Δd is the wear of the grinding wheel compensated by the secondary method, and α is the dressing force-displacement conversion coefficient; Then, the total dressing depth d of the dressing wheel is 总 =d (X) +Δd.

6. A screw processing device, characterized in that: The screw processing device includes a grinding wheel, a dressing wheel and a screw sample; The grinding wheel is used to process the lead screw sample, and the grinding wheel can be dressed by the dressing wheel while processing the lead screw sample; The dressing method of the grinding wheel by the dressing wheel adopts the online dressing method of the grinding wheel as claimed in claim 5.

7. The screw processing device according to claim 6, characterized in that: The screw processing device also includes a screw pitch diameter measuring instrument; The screw middle diameter measuring instrument detects the middle diameter D1 of the screw sample in real time.

8. The screw processing device according to claim 7, characterized in that: The screw processing device further includes a plurality of force sensors; The plurality of force sensors are spaced apart along the outer edge of one side of the dressing wheel. The radial dressing force of the dressing wheel is detected in real time by the plurality of force sensors. The average value of the plurality of radial dressing forces detected in real time by the plurality of force sensors is the actual radial dressing force F. real .

9. The screw processing device according to claim 8, characterized in that: The screw processing device further includes a first slide and a second slide; The first slide can drive the dressing wheel to move along the radial direction of the grinding wheel, and the second slide can drive the dressing wheel to move along the axial direction of the grinding wheel to dress the grinding wheel.

10. The screw processing device according to claim 9, characterized in that: The screw processing device also includes a numerical control system; The numerical control system receives the data sent by the force sensor and the screw diameter measuring instrument, and calculates the value of the force sensor according to ΔR max =(ΔD×tanθ) / 2, d (X) =d0+η×(ΔR max -ΔR (X) ), Δd error =β×(G / G0)×(B / B0)^γ, Δd=[α×(F real -F target )]-Δd error ; Calculate the total dressing depth d at each axial position of the dressing wheel 总 =d (X) +Δd, the numerical control system is based on the total dressing depth d at each axial position of the dressing wheel 总 controlling the first slide and the second slide to dress the grinding wheel; During the trimming process, if the CNC system determines that F real Exceeding target radial dressing force F target The target radial trimming force threshold is based on V new =V old ×(F target / F real )^k calculates the adjusted dressing speed V of the dressing wheel new , the numerical control system adjusts the dressing speed V new Control the speed of the dressing wheel to V new .

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