Honing control device, honing system, and honing method

Abstract

To provide a honing processing controller capable of increasing processing accuracy when performing a grinding step in succession for a plurality of work-pieces, a honing processing system, and a honing processing method.SOLUTION: A honing processing controller 1 includes: a wear amount estimation part 112 which estimates a wear amount of a grindstone in a grinding step on the basis of an inner diameter dimension of a processing hole of a work-piece after the grinding step is performed; a wear amount prediction part 113 which calculates a predicted wear amount of the grindstone in the next grinding step on the basis of the wear amount and the execution frequency of the grinding step with which the grinding step is performed by using the grindstone; a correction amount calculation part 114 which calculates a correction amount with respect to an extension amount of the grindstone in the next grinding step on the basis of the predicted wear amount; and an extension amount determination part 115 which determines an extension amount when extending and moving the grindstone in an extension direction in the next grinding step on the basis of the correction amount.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a honing control device, a honing system, and a honing method. [Background technology]

[0002] A grinding device has been proposed that alternately performs a grinding process in which a mounting fixture with a circular grinding wheel is rotated and moved relative to the workpiece to grind the workpiece with the grinding wheel, and a measurement process in which the amount of wear of the grinding wheel mounted on the mounting fixture is measured, and corrects processing conditions such as the amount of penetration of the grinding wheel into the workpiece based on the amount of wear measured in the measurement process immediately before the grinding process (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-120226 Summary of the Invention [Problem to be solved by the invention]

[0004] When grinding multiple workpieces sequentially using the grinding device described in Patent Document 1, the penetration depth of the grinding wheel into the workpiece is corrected to increase by an amount corresponding to the amount of wear measured in a measurement process after grinding one workpiece, and then the next workpiece is ground. In this case, the grinding wheel continues to wear over time even during grinding of the next workpiece, resulting in the grinding depth of the next workpiece being smaller than the target grinding depth. Therefore, there is a need for a method for correcting the penetration depth of the grinding wheel into the workpiece so that the amount of wear is increased by an amount corresponding to the amount of wear of the grinding wheel during grinding of the next workpiece, compared to the amount of wear measured in the measurement process, thereby ensuring that the grinding depth of all multiple workpieces being ground reaches the target grinding depth.

[0005] The present invention has been made in view of the above-mentioned circumstances, and aims to provide a honing control device, a honing system, and a honing method that can improve the machining accuracy when performing grinding processes on multiple workpieces in succession. [Means for solving the problem]

[0006] In order to achieve the above object, the honing control device according to the present invention comprises: A honing device performs a grinding process for grinding the machining hole of a workpiece, by inserting a honing tool equipped with a grinding stone into the machining hole of the workpiece, rotating the honing tool around the central axis of the machining hole, and expanding the grinding stone from a preset initial position in an expanding direction perpendicular to the central axis and away from the central axis, for each of a plurality of workpieces one by one. A honing control device controls the honing device by outputting control information indicating an expansion amount when the grinding stone is expanded in the expanding direction, a wear amount estimating unit that estimates a wear amount of the grinding wheel in the grinding process based on an inner diameter dimension of the machined hole in the workpiece after the grinding process has been performed; a wear amount prediction unit that calculates a predicted wear amount of the grinding wheel in the next grinding step based on the number of times the grinding step has been performed using the grinding wheel and the wear amount; a correction amount calculation unit that calculates a correction amount for the expansion amount based on the predicted wear amount; and an expansion amount determination unit that determines the expansion amount in the next grinding step based on the correction amount. [Effects of the Invention]

[0007] According to the present invention, the wear amount prediction unit calculates the predicted wear amount of the grinding wheel in the next grinding process based on the number of grinding process executions performed using the grinding wheel and the wear amount of the grinding wheel, and the correction amount calculation unit calculates a correction amount for the expansion amount of the grinding wheel based on the predicted wear amount.Then, the expansion amount determination unit determines the expansion amount of the grinding wheel in the next grinding process based on the calculated correction amount.As a result, when grinding processes are performed on multiple workpieces one by one in sequence, the expansion amounts corresponding to each of the multiple workpieces are appropriately determined, thereby improving the processing accuracy when grinding processes are performed on multiple workpieces in sequence. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a honing system according to an embodiment of the present invention. [Figure 2] 1A and 1B show a part of a honing tool according to an embodiment, in which FIG. 1A is a cross-sectional view showing a state in which the grinding stone is in a reference position, and FIG. 1B is a cross-sectional view showing a state in which the grinding stone is in contact with the inner wall of a machining hole in a workpiece. [Figure 3] FIG. 1 is a side view showing a part of an air micrometer according to an embodiment. [Figure 4] 1 is a block diagram showing a hardware configuration of a honing control device according to an embodiment. FIG. [Figure 5] 2 is a block diagram showing a functional configuration of the honing control device according to the embodiment; FIG. [Figure 6] FIG. 2 is a control block diagram for explaining the operation of the honing system according to the embodiment. [Figure 7] 5 is a flowchart showing an example of the flow of a honing control process executed by the honing control device according to the embodiment. [Figure 8] 1A is a control block diagram for explaining the operation of the honing system according to Comparative Example 1, and FIG. 1B is a control block diagram for explaining the operation of the honing system according to Comparative Example 2. FIG. [Figure 9]FIG. 1A is a diagram showing the results when a grinding process is performed using the honing system according to Comparative Example 1, and FIG. 1B is a diagram showing the results when a grinding process is performed using the honing system according to the embodiment. [Figure 10] FIG. 10(A) is a diagram showing the results when a grinding process is performed using the honing system according to Comparative Example 2, and FIG. 10(B) is a diagram showing the results when a grinding process is performed using the honing system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A honing control device according to an embodiment of the present invention will be described below with reference to the drawings. The honing control device according to this embodiment controls a honing device that performs a grinding process for grinding a hole in a workpiece by inserting a honing tool equipped with a grinding stone into the hole, rotating the honing tool about the central axis of the hole, and expanding the grinding stone from a preset initial position in an expanding direction perpendicular to the central axis of the hole and away from the central axis, thereby controlling the honing device by outputting control information indicating the amount of expansion of the grinding stone in the expanding direction to the honing device. This honing processing control device includes a wear amount estimation unit that estimates the amount of wear of the grinding wheel in the grinding process based on the inner diameter dimensions of the machined hole in the workpiece after the grinding process has been performed, a wear amount prediction unit that calculates the predicted wear amount of the grinding wheel in the next grinding process based on the wear amount and the number of grinding process executions in which the grinding process has been performed using the grinding wheel, a correction amount calculation unit that calculates a correction amount for the expansion amount based on the predicted wear amount, and an expansion amount determination unit that determines the expansion amount in the next grinding process based on the correction amount.

[0010] As shown in FIG. 1 , the honing system according to this embodiment is used to hone the inner wall Wa of a bore hole Wh in a workpiece W. The honing system includes a honing device 2, a measuring device 3 that measures the diameter of the bore hole Wh, and a honing control device 1. The honing device 2 performs a grinding process to grind the bore hole Wh in the workpiece W, sequentially for each of a plurality of workpieces W. The honing device 2 includes a rotating spindle 22, a honing tool 21 connected to the tip of the rotating spindle 22, a drive unit 28 that drives the rotating spindle 22, and a control unit 29 that controls the drive unit 28 based on control information input from the honing control device 1. In FIG. 1 , the workpiece W is positioned such that the central axis J2 of the bore hole Wh coincides with the central axis J1 of the rotating spindle 22. The drive unit 28 rotates the rotating spindle 22 about its central axis J1 as indicated by the arrow AR0 in FIG. 1 while reciprocating the drive unit 28 in the direction of the central axis J1 as indicated by the arrow AR1 in FIG. 1 . As a result, the drive unit 28 rotates the honing tool 21 connected to the rotary spindle 22 while reciprocating the honing tool 21 in the direction of the central axis J2 of the bore Wh, thereby honing the inner wall Wa of the bore Wh.

[0011] 2(A), the honing tool 21 contains, inside, a plurality of grinding wheels 23 that are radially expandable and contractible, a wheel head 24 to which each of the grinding wheels 23 is fixed, a wedge rod 211 for extending and moving the grinding wheels 23 and the wheel head 24, and a return spring (not shown) for retracting the grinding wheels 23 and returning them to a reference position. A wedge 211a for pressing the wheel head 24 is provided at the tip of the wedge rod 211. The wedge rod 211 is also connected to an extension rod (not shown) that is disposed above the wedge rod 211 inside the rotating spindle 22 and is driven by a drive unit 28. The grinding wheels 23 are constantly biased in the retracting direction by the return spring. As a result, as shown in Fig. 2(B), when the driver 28 moves the wedge rod 211 downward via the extension rod (see arrow AR21 in Fig. 2(B)), the wheel head 24 is pressed against the wedge 211a, and the grinding wheel 23 moves in the expansion direction (see arrow AR22 in Fig. 2(B)).On the other hand, when the driver 28 moves the wedge rod 211 upward via the extension rod, the wheel head 24 and the grinding wheel 23 move in the contraction direction.

[0012] With the honing tool 21 inserted into the machining hole Wh, the control unit 29 controls the drive unit 28 to rotate the honing tool 21 about the central axis J2 of the machining hole Wh, while moving the grinding stone 23 from a preset initial position in an expanding direction perpendicular to the central axis J2 and away from the central axis J2. Furthermore, the control unit 29 outputs completion notification information to the honing control device 1 to notify that the grinding process has been completed each time the grinding process for one workpiece W is completed. The workpiece W for which the grinding process in the honing device 2 has been completed is transported to the measuring device 3 (see arrow AR10 in FIG. 1).

[0013] Returning to FIG. 1, the measuring device 3 performs a measuring process to measure the inner diameter of the machined hole Wh in the workpiece W after the grinding process. The measuring device 3 includes an air micrometer 31, a drive unit 38 that drives the air micrometer 31, and a control unit 39 that controls the drive unit 38. As shown in FIG. 3, the air micrometer 31 includes a main body 311, a gauge 312, and a connection unit 313. The main body 311 has a long, cylindrical outer shape, and one end side in the longitudinal direction (the lower end side in FIG. 3) is inserted into the machined hole Wh when measuring the inner diameter dimension of the machined hole Wh. A discharge hole 311a for discharging gas is provided in the side wall of the main body 311. The gauge 312 is cylindrical, and an outer diameter dimension D2 is longer than an outer diameter dimension D1 of the main body 311. The gauge 312 is fixed to the lower end of the main body 311 via the connection unit 313. The drive unit 38 measures the inner diameter dimension of the machined hole Wh in the workpiece W by moving the main body unit 311 and discharging gas from the discharge hole 311a while the main body unit 311 is inserted into the inside of the machined hole Wh in the workpiece W. The control unit 39 generates measurement value information indicating the measurement value of the inner diameter dimension of the machined hole Wh in the workpiece W based on a measurement signal input from the drive unit 38 that corresponds to the size of the gap between the side wall of the main body unit 311 and the inner wall Wa of the machined hole Wh. Furthermore, the control unit 39 outputs completion notification information to the honing control device 1 when measurement of the inner diameter dimension of the machined hole Wh in the workpiece is completed. Furthermore, when the control unit 39 receives measurement value request information (described later) from the honing control device 1, it outputs the generated measurement value information to the honing control device 1 in response to this.

[0014] As shown in FIG. 4, the honing control device 1 includes a CPU (Central Processing Unit) 101, a main memory 102, an auxiliary memory 103, an input unit 105, an interface 106, and a bus 109 connecting the various components. The main memory 102 is a volatile memory such as a random access memory (RAM) and is used as a work area for the CPU 101. The auxiliary memory 103 is a nonvolatile memory such as a magnetic disk or semiconductor memory and stores programs for implementing various functions of the control unit 39. The input unit 105 includes a keyboard, a touch panel, and an interface for connecting to the bus 109. When the input unit 105 receives various operation information input by a user through the keyboard or touch panel, it outputs the received operation information to the CPU 101. The interface 106 is connected to the control unit 29 of the honing device 2 and the control unit 39 of the measuring device 3. The interface 106 converts control information input from the CPU 101 into control signals and outputs them to the control unit 29 of the honing device 2. Furthermore, the interface 106 converts measurement value request information, which will be described later and is input from the CPU 101, into a measurement value request signal and outputs it to the control unit 39 of the measuring device 3. Furthermore, the interface 106 outputs measurement value information, which is input from the control unit 39 of the measuring device 3, to the CPU 101.

[0015] 5, the CPU 101 functions as a measurement value acquisition unit 111, a wear amount estimation unit 112, a wear amount prediction unit 113, a correction amount calculation unit 114, an expansion amount determination unit 115, a control information output unit 116, and a grinding process execution count monitoring unit 117. The auxiliary storage unit 103 has a target value storage unit 131 that stores target value information indicating a target value for the inner diameter of the machined hole Wh in the workpiece W, a measurement value storage unit 132 that stores measurement value information acquired from the measuring device 3, and a wear amount history storage unit 133 that stores wear amount history information indicating the history of the wear amount of the grinding wheel 23 of the honing device 2. The measurement value storage unit 132 stores the measurement value information indicating the actual inner diameter dimension of the machined hole Wh in the workpiece W in association with grinding process execution count information indicating the number of times the grinding process was executed before the grinding process of the workpiece W was executed. The wear amount history storage unit 133 stores wear amount history information composed of the wear amount calculated based on the measurement value information, the expansion amount of the grinding wheel 23, and the correction amount, and the corresponding number of grinding processes.

[0016] The auxiliary storage unit 103 also has a function storage unit 134 that stores information indicating a wear amount transition function used when calculating the predicted wear amount, a grinding process execution count storage unit 135 that stores grinding process execution count information indicating the number of times the grinding process is executed by the honing device 2, and an expansion amount storage unit 136 that stores expansion amount information indicating the determined expansion amount. The function storage unit 134 stores information indicating the wear amount transition function expressed, for example, by the following equation (1):

[0017]

number

[0018] Here, n indicates the number of times the grinding process is performed, which is the number of times the grinding process is performed using the grinding wheel 23 after it has been replaced with a new one, e3[n] indicates the predicted amount of wear of the grinding wheel 23 in the nth grinding process, and a and b indicate coefficients.

[0019] The value indicated by the grinding process execution count information stored in the grinding process execution count memory unit 135 is initialized to "0" each time the grinding wheel 23 of the honing device 2 is replaced with a new grinding wheel 23 and the honing process control process described below is executed.

[0020] The measurement value acquisition unit 111 acquires measurement value information output from the measurement device 3 by outputting measurement value request information that requests the measurement device 3 to output measurement value information. The measurement value acquisition unit 111 stores the acquired measurement value information in the measurement value storage unit 132.

[0021] The wear amount estimation unit 112 executes a wear amount estimation process to estimate the wear amount of the grinding wheel 23 during the grinding process based on the inner diameter dimension of the machined hole Wh in the workpiece W after the grinding process, which is indicated by the measurement value information acquired by the measurement value acquisition unit 111. Specifically, the wear amount estimation unit 112 acquires expansion amount information indicating the expansion amount of the grinding wheel 23 during the grinding process of the workpiece W, which corresponds to the measurement value information stored in the expansion amount storage unit 136. The wear amount estimation unit 112 then calculates a theoretical inner diameter dimension assuming no wear of the grinding wheel 23, based on the expansion amount indicated by the acquired expansion amount information and the measurement value of the inner diameter dimension of the machined hole Wh indicated by the measurement value information. Next, the wear amount estimation unit 112 calculates an amount corresponding to the difference between the calculated theoretical inner diameter dimension and the actual inner diameter dimension of the machined hole Wh in the workpiece W after the grinding process, which is indicated by the measurement value information. The wear amount estimation unit 112 then converts the amount corresponding to the difference using the following relational expression (2) to calculate the amount obtained as the estimated wear amount of the grinding wheel 23.

[0022]

number

[0023] Here, n indicates the number of times the grinding process has been performed using the grinding wheel 23 after it has been replaced with a new one, e1[n] indicates the amount equivalent to the aforementioned differential dimension of the workpiece W that was the subject of the nth grinding process, and e2[n] indicates the amount of wear of the grinding wheel 23 in the nth grinding process.

[0024] In addition, the wear amount estimation unit 112 stores wear amount information indicating the estimated wear amount of the grinding wheel 23 in the wear amount history memory unit 133 in association with grinding process execution count information indicating the number of times the corresponding grinding process has been performed.

[0025] The wear amount prediction unit 113 executes a wear amount estimation step of calculating a predicted wear amount of the grinding wheel 23 in the next grinding step, based on the number of times the grinding step was performed in the past when the grinding step was performed using the grinding wheel 23 and the wear amount of the grinding wheel 23. Specifically, the wear amount prediction unit 113 first generates a wear amount transition function that represents the transition of the wear amount of the grinding wheel 23 with respect to the number of times the grinding step was performed, based on the history of the wear amount of the grinding wheel 23 from immediately after the grinding wheel 23 was replaced with a new grinding wheel 23, which is stored in the wear amount history storage unit 133. Here, the wear amount prediction unit 113 calculates, as the coefficients a and b in the above-mentioned equation (1), the coefficients a and b that minimize the evaluation value calculated using the evaluation function expressed by, for example, the following equation (3):

[0026]

number

[0027] Here, e2[n] indicates the amount of wear of the grinding wheel 23 in the n-th grinding step, a and b indicate coefficients, and J indicates an evaluation value.

[0028] That is, the wear amount prediction unit 113 generates a wear amount transition function by determining the coefficients a and b by fitting the relational expression of Equation (1) by the least squares method to the history of past wear amounts of the grinding wheel 23. Then, the wear amount prediction unit 113 calculates the predicted wear amount in the next grinding process using the generated wear amount transition function, and notifies the correction amount calculation unit 114 of predicted wear amount information indicating the calculated predicted wear amount.

[0029] The correction amount calculation unit 114 executes a correction amount calculation step of calculating a correction amount for the expansion amount of the grinding wheel 23 in the next grinding step, based on the difference between the target value of the inner diameter dimension of the workpiece W and the actual inner diameter dimension of the workpiece W after the grinding step indicated by the measurement value information, and the predicted wear amount indicated by the predicted wear amount information notified from the wear amount prediction unit 113. Here, the correction amount calculation unit 114 first calculates a provisional correction amount using the relational expression expressed by the following equation (4).

[0030]

number

[0031] Here, u0[n] indicates the provisional correction amount, E0[n] (E0[i]) indicates the difference between the target value of the inner diameter dimension of the workpiece W and the actual inner diameter dimension of the workpiece W after grinding in the nth (ith) grinding process indicated by the measurement value information, and k p , k i denotes the gain coefficient. Also, the gain coefficient k p , k i are set to, for example, "1.0" and "0.075".

[0032] Then, the correction amount calculation unit 114 calculates the correction amount by adding the calculated provisional correction amount to the aforementioned predicted wear amount, and notifies the extension amount determination unit 115 of the correction amount information indicating the calculated correction amount.

[0033] The expansion amount determination unit 115 executes an expansion amount determination process to determine the expansion amount when the grinding wheel 23 is expanded in the expansion direction in the next grinding process. Specifically, the expansion amount determination unit 115 acquires expansion amount information indicating the expansion amount used in the grinding process performed immediately before and stored in the expansion amount memory unit 136. Next, the expansion amount determination unit 115 determines the amount obtained by adding the correction amount indicated by the correction amount information notified by the correction amount calculation unit 114 to the expansion amount indicated by the acquired expansion amount information as the expansion amount to be used in the next grinding process. Furthermore, when the grinding wheel 23 in the honing device 2 is replaced with a new grinding wheel 23, the expansion amount determination unit 115 determines the expansion amount based only on the target value of the inner diameter dimension of the workpiece W. Then, the expansion amount determination unit 115 notifies the control information output unit 116 of the expansion amount information indicating the determined expansion amount and stores it in the expansion amount memory unit 136.

[0034] The control information output unit 116 generates control information based on the expansion amount information notified from the expansion amount determination unit 115, and outputs the generated control information to the honing device 2. The grinding process execution count monitoring unit 117 monitors the number of times the grinding process is executed by the honing device 2. The grinding process execution count monitoring unit 117 increments the number of times the grinding process is executed by one each time completion notification information is input from the honing device 2, starting immediately after the grinding wheel 23 in the honing device 2 is replaced with a new grinding wheel 23. Furthermore, when the user performs an operation on the input unit 105 to reset the number of times the grinding process is executed after replacing the grinding wheel 23 with a new grinding wheel 23, the grinding process execution count monitoring unit 117 initializes the number of times the grinding process is executed to "0".

[0035] The control executed by the honing system according to this embodiment can be expressed by a control model as shown in Fig. 6. Here, n indicates the number of times the grinding process has been performed since immediately after the replacement of the grinding wheel 23 in the honing device 2, r[n] indicates the target value of the inner diameter of the machined hole Wh in the workpiece W in the nth grinding process, and y[n] indicates the actual inner diameter of the machined hole Wh in the workpiece W after the nth grinding process. Furthermore, e0[n] indicates an error component resulting from the actual wear of the grinding wheel 23 and elastic deformation of the workpiece W in the nth grinding process, and d0[n] indicates a measurement error component in the measuring device 3. The honing control device 1 first calculates a function C from the difference E0[n] between the target value r[n] of the inner diameter of the machined hole Wh and the actual inner diameter y[n] of the machined hole Wh. B The temporary correction amount u0[n] for the expansion amount of the grinding wheel 23 in the next grinding process is calculated using the function C B is expressed, for example, by the aforementioned equation (4). The honing control device 1 also calculates the theoretical inner diameter x0[n] after the n-th grinding process, which corresponds to the sum of the theoretical inner diameter x0[n-1] of the machined hole Wh, which would occur if no wear of the grinding wheel 23 were to occur after the (n-1)th grinding process, and the calculated provisional correction amount u0[n]. Next, the honing control device 1 calculates the difference e1[n] between the calculated theoretical inner diameter x0[n] and the measurement value y[n] of the actual inner diameter of the machined hole Wh after the n-th grinding process, measured by the measuring device 3. The honing control device 1 then estimates the aforementioned wear amount e2[n] using the function F, and stores the result in the wear amount history storage unit 133. Here, the function F is expressed, for example, by the aforementioned equation (2).

[0036] Next, the honing control device 1 predicts the wear amount e3[n] of the grinding wheel 23 in the next grinding process based on the wear amount history of the grinding wheel 23 stored in the wear amount history storage unit 133. The honing control device 1 then calculates the sum of the aforementioned temporary correction amount u0[n] and the predicted wear amount e3[n] as the correction amount for the next grinding process, and determines the expansion amount of the grinding wheel 23 based on the calculated correction amount. Here, the honing control device 1 generates control information indicative of the determined expansion amount of the grinding wheel 23 and outputs it to the honing device 2. Meanwhile, the honing device 2 performs the grinding process of the machined hole Wh of the workpiece W based on the control information input from the honing control device 1. As a result, a workpiece W having a machined hole Wh with an inner diameter dimension x1[n] is produced.

[0037] Next, the honing control process executed by the honing control device 1 according to this embodiment will be described with reference to Fig. 7. This honing control process is started when the user performs an operation to start the honing control process via the input unit 105 after replacing the grindstone 23 of the honing device 2.

[0038] First, the expansion amount determination unit 115 determines the expansion amount based only on the target value of the inner diameter dimension of the workpiece W (step S1). Next, the control information output unit 116 generates control information based on the expansion amount information notified from the expansion amount determination unit 115, and outputs the generated control information to the honing device 2 (step S2). At this time, the honing device 2 performs honing of the machined hole Wh of the workpiece W based on the control information input from the honing control device 1. When the honing of the workpiece W is completed by the honing device 2, the workpiece W is transported to the measuring device 3. Then, the measuring device 3 measures the inner diameter dimension of the machined hole Wh of the workpiece W, and outputs measurement value information indicating the measured value of the inner diameter dimension to the honing control device 1.

[0039] Next, the measurement value acquisition unit 111 determines whether or not the grinding process of the workpiece W by the honing device 2 and the measurement of the inner diameter dimension of the machined hole Wh of the workpiece W by the measuring device 3 have been completed (step S3). Here, if the measurement value acquisition unit 111 has acquired completion notification information from both the honing device 2 and the measuring device 3, it determines that the grinding process of the machined hole Wh of the workpiece W and the measurement of the inner diameter dimension have been completed. If the measurement value acquisition unit 111 determines that the grinding process of the machined hole Wh of the workpiece W and the measurement of the inner diameter dimension have not yet been completed (step S3: No), the processing of step S11 described below is executed.

[0040] On the other hand, when the measurement value acquisition unit 111 determines that the grinding process and measurement of the inner diameter dimension of the machined hole Wh in the workpiece W have been completed (step S3: Yes), it outputs the above-mentioned measurement value request information to the measurement device 3, thereby acquiring measurement value information output from the measurement device 3 (step S4). Thereafter, the wear amount estimation unit 112 estimates the wear amount of the grinding wheel 23 in the grinding process based on the inner diameter dimension of the machined hole Wh in the workpiece W after the grinding process, which is indicated by the measurement value information acquired by the measurement value acquisition unit 111. Then, the wear amount estimation unit 112 stores the wear amount information indicating the estimated wear amount of the grinding wheel 23 in the wear amount history storage unit 133 in association with grinding process execution count information indicating the number of times the corresponding grinding process has been performed (step S5).

[0041] Next, the correction amount calculation unit 114 calculates a provisional correction amount for the expansion amount of the grinding wheel 23 in the next grinding process based on the difference between the target value of the inner diameter dimension of the workpiece W and the actual inner diameter dimension of the workpiece W after the grinding process indicated by the measurement value information (step S6). Subsequently, the wear amount prediction unit 113 generates a wear amount transition function from the history of past wear amounts of the grinding wheel 23, and calculates the predicted wear amount in the next grinding process using the generated wear amount transition function (step S7).

[0042] Thereafter, the correction amount calculation unit 114 calculates the correction amount by adding the calculated provisional correction amount to the predicted wear amount (step 8). Next, the expansion amount determination unit 115 determines the amount obtained by adding the correction amount calculated by the correction amount calculation unit 114 to the expansion amount used in the immediately preceding grinding process as the expansion amount to be used in the next grinding process (step S9). Next, the control information output unit 116 generates control information based on the expansion amount information indicating the expansion amount determined by the expansion amount determination unit 115, and outputs the generated control information to the honing device 2 (step S10).

[0043] Thereafter, the measurement value acquiring unit 111 determines whether or not a preset grindstone replacement time has arrived (step S11). If the measurement value acquiring unit 111 determines that the grindstone replacement time has not yet arrived (step S11: No), it executes the process of step S3 again. On the other hand, if the measurement value acquiring unit 111 determines that the grindstone replacement time has arrived (step S11: Yes), the honing process control process ends.

[0044] Next, the performance of the honing system according to this embodiment will be described in comparison with a honing system according to a comparative example. The control executed by the honing system according to comparative example 1 can be expressed by a control model as shown in Fig. 8(A). In Fig. 8(A), the same symbols as in Fig. 6 have the same meanings as in Fig. 5. In the honing system according to comparative example 1, a honing control device 8001 calculates a function k from a difference dimension E0[n] between a target value r[n] of the inner diameter dimension of the machined hole Wh and an actual inner diameter dimension y[n] of the machined hole Wh. p This system differs from the honing system according to the embodiment in that it calculates the correction amount u8[n] for the expansion amount of the grinding wheel 23 in the next grinding process using the function k prepresents a function that outputs the differential dimension E0[n] as is with a gain of 1. The control executed in the honing system according to Comparative Example 2 can be expressed by a control model as shown in FIG. 8(B). In FIG. 8(B), the same symbols as those in FIG. 6 have the same meanings as those in FIG. 5. In the honing system according to Comparative Example 2, the honing control device 9001 calculates the function C from the differential dimension E0[n] between the target value r[n] of the inner diameter dimension of the machined hole Wh and the actual inner diameter dimension y[n] of the machined hole Wh. B This system differs from the honing system according to Comparative Example 1 in that it calculates the correction amount u9[n] for the expansion amount of the grinding wheel 23 in the subsequent grinding process using the function C B is the function C explained in the embodiment. B That is, the honing system according to Comparative Example 2 differs from the honing system according to Comparative Example 1 in that PI feedback is performed on the correction amount u9[n] based on the differential dimension E0[n].

[0045] Next, the results of performing 70 grinding processes on the machined holes Wh of 70 workpieces W using the honing system according to Comparative Example 1 and the honing system according to the present embodiment will be described with reference to FIGS. 9A and 9B. Note that FIG. 9A shows the results for the honing system according to Comparative Example 1, and FIG. 9B shows the results for the honing system according to the present embodiment. The left-hand diagrams in each of FIGS. 9A and 9B show the deviations of the inner diameters of the machined holes Wh from the target values ​​when the grinding process was performed 1 to 35 times after the grinding wheel 23 was replaced. The right-hand diagrams show the deviations of the inner diameters of the machined holes Wh from the target values ​​when the grinding process was performed 36 to 70 times after the grinding wheel 23 was replaced. The vertical axis of the right-hand diagram corresponds to a four-fold enlargement of the vertical axis of the left-hand diagram. 9(A) and 9(B) show that when the workpiece W is machined with the honing system according to the present embodiment, the amount of deviation and the variation in the amount of deviation are reduced, particularly from 36 to 70 times, compared to when the workpiece W is machined with the honing system according to Comparative Example 1. Specifically, with the honing system according to Comparative Example 1, the average amount of deviation was −0.47 μm and the standard deviation was 0.51 μm, whereas with the honing system according to the present embodiment, the average amount of deviation was −0.08 μm and the standard deviation was 0.36 μm, which are reduced values. This demonstrates that the honing system according to the present embodiment improves the machining accuracy of the machined hole Wh in the workpiece W compared to the honing system according to Comparative Example 1.

[0046] 10(A) and 10(B) show the results of 15 grinding processes performed on the holes Wh of 15 workpieces W using the honing system according to Comparative Example 2 and the honing system according to the present embodiment. FIG. 10(A) shows the results for the honing system according to Comparative Example 2, and FIG. 10(B) shows the results for the honing system according to the present embodiment. The results shown in FIGS. 10(A) and 10(B) indicate that when the workpieces W were machined using the honing system according to the present embodiment, the amount of misalignment and the variation in the amount of misalignment were reduced compared to when the workpieces W were machined using the honing system according to Comparative Example 2. This indicates that the wear amount estimation function of the wear amount prediction unit 113 in the honing system according to the present embodiment significantly contributes to improving the machining accuracy of the holes Wh of the workpieces W.

[0047] As described above, in the honing process control device 1 of this embodiment, the wear amount prediction unit 113 calculates the predicted wear amount of the grinding wheel in the next grinding process based on the number of grinding process executions in which the grinding process was performed using the grinding wheel 23 and the wear amount of the grinding wheel 23. Furthermore, the correction amount calculation unit 114 calculates a correction amount for the expansion amount of the grinding wheel 23 based on the predicted wear amount, and the expansion amount determination unit 115 determines the expansion amount of the grinding wheel 23 in the next grinding process for the workpiece W based on the calculated correction amount. As a result, the expansion amount corresponding to each of the multiple workpieces W when the grinding processes are performed sequentially on the multiple workpieces W one by one is appropriately determined, and the processing accuracy when the grinding processes are performed sequentially on the multiple workpieces W can be improved.

[0048] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations of the above-described embodiments. For example, the wear amount transition function may have a shape other than that of Equation (1).

[0049] In the embodiment, an example has been described in which the wear amount prediction unit 113 calculates the predicted wear amount using a wear function, but this is not limited to this, and the predicted wear amount may also be calculated using a trained model that has been machine-learned based on, for example, the difference between the theoretical inner diameter dimension and the actual inner diameter dimension measured by the measuring device 3, the number of times the grinding process is performed, and the actual wear amount of the grinding wheel 23.

[0050] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to these. The present invention includes any combination of the embodiments and modifications, and any combination to which appropriate modifications have been made. [Industrial Applicability]

[0051] The present invention is suitable as a honing device that performs honing on a plurality of workpieces in sequence. [Explanation of symbols]

[0052] 1: Honing processing control device, 2: Honing processing device, 3: Measuring device, 21: Honing tool, 22: Rotating spindle, 23: Grinding wheel, 24: Grinding wheel head, 28, 38: Drive unit, 29, 39: Control unit, 31: Air micrometer, 101: CPU, 102: Main memory unit, 103: Auxiliary memory unit, 105: Input unit, 106: Interface, 109: Bus, 111: Measurement value acquisition unit, 112: Wear amount estimation unit, 113: Wear amount prediction unit, 114: Correction amount calculation unit unit, 115: expansion amount determination unit, 116: control information output unit, 117: grinding process execution count monitoring unit, 131: target value storage unit, 132: measurement value storage unit, 133: wear amount history storage unit, 134: function storage unit, 135: grinding process execution count storage unit, 136: expansion amount storage unit, 211: wedge rod, 211a: wedge, 311: main body unit, 311a: discharge hole, 312: gauge, 313: connection unit, J1, J2: central axis, W: workpiece, Wa: inner wall, Wh: machining hole

Claims

1. A honing device performs a grinding process for grinding the machining hole of a workpiece by inserting a honing tool equipped with a grinding stone into the machining hole of the workpiece, rotating the honing tool around the central axis of the machining hole, and expanding the grinding stone from a preset initial position in an expanding direction perpendicular to the central axis and away from the central axis, the honing device controls the honing device by outputting control information indicating the amount of expansion when the grinding stone is expanded in the expanding direction to the honing device, a wear amount estimating unit that estimates a wear amount of the grinding wheel in the grinding process based on an inner diameter dimension of the machined hole in the workpiece after the grinding process has been performed; a wear amount prediction unit that calculates a predicted wear amount of the grinding wheel in the next grinding step based on the number of times the grinding step has been performed using the grinding wheel and the wear amount; a correction amount calculation unit that calculates a correction amount for the expansion amount based on the predicted wear amount; and an expansion amount determination unit that determines the expansion amount in the next grinding process based on the correction amount. Honing processing control device.

2. the wear amount prediction unit generates a wear amount transition function that indicates a transition of the wear amount with respect to the number of times the grinding process is performed, based on a history of the past wear amounts, and calculates the predicted wear amount in the next grinding process using the generated wear amount transition function. The honing control device according to claim 1 .

3. The wear amount transition function is expressed by the following formula (1), where n is the number of times the grinding process is performed, e3[n] is the predicted wear amount in the n-th grinding process, and a and b are coefficients: The honing control device according to claim 2 . [Equation 1] ...Formula (1)

4. the wear amount prediction unit determines the coefficients by fitting the relational expression of the formula (1) to the history of the past wear amounts by a least squares method, thereby generating the wear amount transition function. The honing control device according to claim 3 .

5. a honing device that performs a grinding process for grinding the processing hole of a workpiece one by one, the grinding tool having a grinding stone attached thereto being inserted into the processing hole of the workpiece, and the grinding stone being expanded and moved from a preset initial position in an expanding direction perpendicular to the central axis and away from the central axis while rotating the honing tool around the central axis of the processing hole; a measuring device for measuring the inner diameter dimension of the processed hole; a honing control device that controls the honing device by outputting control information to the honing device that indicates an expansion amount when the grinding wheel is expanded in the expansion direction, the expansion amount being determined based on the inner diameter dimension of the processed hole after the grinding process measured by the measuring device, The honing control device includes: a wear amount estimating unit that estimates a wear amount of the grinding wheel in the grinding process based on an inner diameter dimension of the machined hole in the workpiece after the grinding process has been performed; a wear amount prediction unit that calculates a predicted wear amount of the grinding wheel in the next grinding step based on the number of times the grinding step has been performed using the grinding wheel and the wear amount; a correction amount calculation unit that calculates a correction amount for the expansion amount based on the predicted wear amount; an expansion amount determination unit that determines the expansion amount in the next grinding process based on the correction amount; a control information output unit that outputs the control information indicating the expansion amount determined by the expansion amount determination unit to the honing device, Honing processing system.

6. A honing method in which a grinding process is sequentially performed one by one on each of a plurality of workpieces having machining holes, a grinding process in which a honing tool provided with a grinding stone is inserted into a machining hole of one workpiece selected from the plurality of workpieces, and the honing tool is rotated around a central axis of the machining hole, while the grinding stone is expanded from a preset initial position in an expanding direction perpendicular to the central axis and away from the central axis, thereby grinding the machining hole of the one workpiece; a measuring step of measuring an inner diameter dimension of the processed hole after the grinding step; a wear amount calculation step of calculating a wear amount of the grinding wheel in the grinding step based on the inner diameter dimension measured in the measurement step; a wear amount estimation step of calculating a predicted wear amount of the grinding wheel in the next grinding step based on the number of times the grinding step has been performed using the grinding wheel and the wear amount; a correction amount calculation step of calculating a correction amount for an expansion amount when the grinding wheel is expanded in the expansion direction based on the predicted wear amount; and an expansion amount determination step of determining the expansion amount in the subsequent grinding step based on the correction amount. Honing method.

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