JP2015182171A - Method and device for fastening workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a decline in a fastening force between a first workpiece and a second workpiece and to obtain a prescribed fastening force, when a press load fluctuates due to a secular change of working tools, deviation of each workpiece rod, etc., by correcting a target value to deal with the fluctuation.SOLUTION: A method for fastening a workpiece includes: a first processing step (at ST03) for processing a first workpiece on the basis of a target value; a pressing step (at ST04) for pressing a second workpiece to a processing position on the first workpiece; a load acquisition step (at ST09) for acquiring a press load at the pressing step; and a target value correction step (at ST15, 16) for correcting the target vale on the basis of the acquired load. If the target value is corrected in the target value correction step, in the first processing step to be performed after the correction, processing is performed to a next first workpiece on the basis of the corrected target value.

Description

  The present invention relates to improvement of a work fastening technique.

  Camshafts in which a cam is integrally formed on a shaft are widely used in practice. When the camshaft is cut out from a large-diameter round bar (or thick-walled cylinder), the cutting allowance increases and the material yield is not good. When a camshaft is manufactured from a forged product by machining, the material yield is improved, but a forging machine and a forging die are indispensable, and the manufacturing cost increases in small-scale production.

  An assembly camshaft does not require forging or large-diameter round bars and is suitable for small-scale production. An assembly camshaft is known, for example, in which a cam lobe (cam block) is positioned on a round cylindrical shaft body and fixed by caulking (for example, Patent Document 1 (FIG. 2)). (See Patent Document 2 (FIG. 5)).

  As shown in FIG. 2 of Patent Document 1, the cam lobe (2) is fitted on the shaft (4) (the numbers in parentheses indicate the symbols described in Patent Document 1. The same applies hereinafter), and a pair of raised portions It is fixed at (9, 9). The raised portions (9, 9) correspond to the caulking mountain.

  As shown in FIG. 5 of Patent Document 2, the raised portion is cut by a roller (65c) having a protrusion (99) on the outer periphery (the numbers in parentheses indicate the symbols described in Patent Document 2. The same applies hereinafter). Is formed.

Since the hard material is cut, the protrusion (99) of the roller (65c) gradually wears. As the wear progresses, the height of the raised portion becomes gradually lower, and it becomes difficult to obtain a predetermined fastening force.
It is desired that the fastening force does not decrease even when the roller (65c) is worn.

  Thousands of shafts are manufactured together. The production unit at this time is called a rod. Because the shafts in one rod have the same variation tendency, the variation in outer diameter is small. However, if one rod is processed followed by another rod, the variation in outer diameter increases. Alternatively, the machining amount may vary under the influence of a so-called temperature drift in which the accuracy of the hydraulic control mechanism varies due to a temperature change. As described above, there is a possibility that the fastening force varies due to various factors, and some of them do not reach the predetermined fastening force. For this reason, specifications have been confirmed by performing slip torque inspection for all of them. Since all inspections are performed, inspection costs increase.

  While it is required to prevent the fastening force from being reduced, the predetermined fastening force is maintained even when the roller (caulking roller) is worn, affected by temperature drift, or when the outer diameter of the shaft body fluctuates. Therefore, a work fastening technique that can achieve the above is desired.

JP 2008-144718 A JP2012-250295A

  The present invention provides a predetermined fastening force even when a machining tool represented by a caulking roller is worn, affected by temperature drift, or when the outer diameter of a first workpiece represented by a shaft body varies. It is an object to provide a work fastening technique that can achieve the above.

The invention according to claim 1 is a first machining step of machining a first workpiece based on a target value, a pressing step of pressing a second workpiece toward a machining location of the first workpiece, and a pressing in the pressing step It has a load acquisition step of acquiring a load and a target value correction step of correcting the target value based on the acquired load, and is a workpiece fastening method for fastening the second workpiece to the first workpiece,
When the target value is corrected in the target value correcting step, the first machining step performed after the correction performs processing on the next first workpiece based on the corrected target value.

  In the invention which concerns on Claim 2, a target value correction process corrects a target value based on the pressing load when pressing a 2nd workpiece | work to a predetermined position.

  In the invention which concerns on Claim 3, a 1st process process is a process which caulks the outer periphery of a shaft-shaped 1st workpiece | work, and a pressing process inserts a 1st workpiece | work through the through-hole provided in the 2nd workpiece | work. The edge of the through hole of the second workpiece is pressed against the ridge formed in the first processing step.

  In the invention which concerns on Claim 4, after a pressing process, the position information acquisition process which acquires the positional information on the 2nd workpiece | work pressed by the pressing process, and the 1st workpiece | work is processed based on the acquired positional information. The second workpiece is fastened to the first workpiece between the machining location by the first machining step and the machining location by the second machining step.

  In the invention which concerns on Claim 5, a 1st workpiece | work is a shaft main body, and a 2nd workpiece | work is a cam lobe.

  According to the invention which concerns on Claim 6, the 1st processing mechanism which processes a 1st workpiece | work based on target value, the pressing mechanism which presses a 2nd workpiece toward the process location of the said 1st workpiece | work, and this pressing mechanism A load acquisition mechanism that acquires the pressing load by the control unit, and a control unit that corrects the target value based on the acquired load and provides the corrected target value to the first machining mechanism for the next first workpiece. And a work fastening device for fastening the second work to the first work.

  In the invention which concerns on Claim 1, it has the target value correction process which corrects a target value based on a load, and when a target value is corrected in this target value correction process, the 1st process process implemented after the correction Applies processing to the next first workpiece based on the corrected target value. That is, when the pressing load fluctuates due to a change in the processing tool with time, variation of each workpiece rod, etc., the target value is corrected to cope with it, so that the fastening force between the first workpiece and the second workpiece is reduced. And a predetermined fastening force can be obtained.

  In the invention according to claim 2, the target value is corrected based on the pressing load when the second workpiece is pressed to a predetermined position. The pressing load is measured when the second workpiece is pressed to a predetermined position. Even if there are variations in the dimensions of the machining location formed on the first workpiece and the dimensions of the second workpiece, the pressing load is measured under a predetermined condition (predetermined position), so that the measurement reliability is increased. That is, by using the pressing load at a predetermined position, the pressing load of each second workpiece can be reflected in the machining amount of the next workpiece based on the same condition.

  In the invention which concerns on Claim 3, the outer periphery of a shaft-shaped 1st workpiece | work is caulked, the 1st workpiece | work is inserted in the through-hole provided in the 2nd workpiece | work, and the 2nd workpiece | work was formed in the 1st process formed. Press the edge of the through hole. Even if there is a variation in the outer dimensions of the shaft-shaped first workpiece or a variation in the inner diameter (hole diameter) of the through hole of the second workpiece, a decrease in the fastening force between the first workpiece and the second workpiece is suppressed. be able to.

  In the invention which concerns on Claim 4, after a pressing process, the position information acquisition process which acquires the positional information on the 2nd workpiece | work pressed by the pressing process, and the 1st workpiece | work is processed based on the acquired positional information. Since 2 processing steps are included, when fastening a 1st workpiece | work between the process location by a 1st process process and the process location by a 2nd processing process, appropriate fastening force can be obtained. That is, in the first machining step, the first workpiece and the second workpiece are securely fastened by performing machining based on the target value reflecting the pressing load. In the second machining step, the position of the second workpiece is determined. Since processing can be performed at an appropriate position based on information, it is possible to favorably support the fastening of the first workpiece and the second workpiece.

  In the invention which concerns on Claim 5, a 1st workpiece | work is a shaft main body and a 2nd workpiece | work is a cam lobe, According to this invention, a cam lobe can be fastened with an appropriate fastening force to a shaft.

  According to the sixth aspect of the invention, the first processing mechanism that processes the first workpiece based on the target value, the pressing mechanism that presses the second workpiece toward the processing location of the first workpiece, and the pressing mechanism. A load acquisition mechanism for acquiring the pressing load, and a control unit that corrects the target value based on the acquired load and gives the corrected target value to the first machining mechanism for the next first workpiece, A workpiece fastening device for fastening a second workpiece to one workpiece is provided. When the pressing load fluctuates due to a change over time of the processing tool or a variation of each workpiece rod, etc., the target value is corrected to cope with the problem. A decrease in the fastening force between them can be suppressed.

It is a side view of the work fastening device concerning the present invention. It is a side view of a shaft main body. It is a front view of a cam lobe. It is sectional drawing of a cam lobe. FIG. 5 is a view taken in the direction of arrow 5 in FIG. 1. It is an effect | action figure of a 1st process mechanism. FIG. 7 is a view taken in the direction of arrow 7 in FIG. 1. It is a figure explaining a 1st crimping process and a pressing process. It is a figure explaining the correlation of pressing load and slip torque. It is a figure explaining a 2nd crimping process. It is a flowchart explaining the workpiece | work fastening method which concerns on this invention. It is a figure explaining an example of the procedure which determines a pressing target load. It is a figure explaining an example of the procedure which defines the cutting amount. It is a rework flowchart.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

  As shown in FIG. 1, a work fastening device 10 includes a base 11, a box frame 12 standing on the base 11, a headstock 13 provided on the top of the box frame 12, and a box frame. 12, a tailstock 14 provided at a lower portion of the frame 12, a rack 15, a linear guide 16 and a ball screw 17, which are provided vertically and parallel to the box frame 12, and a linear guide 16 so as to be vertically movable. 15 and a first processing mechanism 20 having a first drive motor 19 that drives the pinion 18, and a guide 15 that is disposed below the first processing mechanism 20 and is vertically movable by a linear guide 16 and is guided to the rack 15. A second processing mechanism 23 having an intermeshing pinion 21 and a second drive motor 22 for driving the pinion 21, and arranged below the second processing mechanism 23. Is vertically movably guided by a line guide 16 and a pressing mechanism 25 is moved by the ball screw 17.

The headstock 13 is a main member that grips and rotates a shaft main body 26 as a first workpiece and rotates around the shaft, and includes a collet 27 that chucks the shaft main body 26 and a spindle motor 28 that rotates the collet 27.
The tailstock 14 is a member that supports the shaft body 26 together with the headstock 13, and includes a center 29 and a cylinder unit 31 that moves up and down the center 29.

  The pressing mechanism 25 includes a ball screw 17, a third drive motor 32 that rotates the ball screw 17, a slider 33 that is moved by the ball screw 17, a bracket 34 that is fixed to the slider 33 and extends to the front, and the bracket 34. The pallet 35 is supported by The bracket 34 is provided with a pallet turning motor 36 that rotates the pallet 35 about the vertical axis.

  Further, the workpiece fastening device 10 includes a first position sensor 39 that is attached to the first machining mechanism 20 and detects the height position of the first caulking roller 38, and a height of the second caulking roller 41 that is attached to the second machining mechanism 23. Position information from a second position sensor 42 that detects the position, a third position sensor 43 that is attached to the slider 33 and detects the height position of the upper surface of the pallet 35, and first to third position sensors 39, 42, 43 And a control unit 45 that controls the first to third drive motors 19, 22, and 32.

  The control unit 45 includes a load acquisition mechanism 44 that obtains a pressing load by converting the current value of the third drive motor 32 into a pressing load.

As shown in FIG. 2, the shaft main body 26 which is a specific example of the first workpiece is a steel cylinder. The tip of the center 29 enters the hollow portion.
As shown in FIG. 3, the cam lobe 46, which is a specific example of the second workpiece, has a through hole 47 having an inner diameter slightly larger than the outer diameter of the shaft body 26.
As shown in FIG. 4, a first caulking recess 48 and a second caulking recess 49 are formed on the upper and lower surfaces of the cam lobe 46 and at the edge of the through hole 47.

  As shown in FIG. 5, the first processing mechanism 20 includes an elevating frame 51 that moves up and down in the drawing front and back directions, two subframes 52 and 52 extending from both ends of the elevating frame 51, and these subframes 52. 52, rails 53, 53 provided in the shape of a V, sub-sliders 54, 54 movably attached to the rails 53, 53, and supported by these sub-sliders 54, 54 on the base side. Racks 55, 55 are formed and plates having left and right first caulking rollers 38L, 38R (L is a left and R is a subscript indicating right. Since the drawing is viewed from below, the left and right are reversed). 56, 56, a drive source 57 attached to the center of the elevating frame 51, and supported by the drive source 57 to move toward the shaft body 26 and racks 58 on both sides. 8, a movable member 59 having a central first caulking roller 38C (C is a subscript indicating the center) at the tip, and a liftable frame 51 or sub-frames 52 and 52, which are rotatably mounted on racks 58 and 58. First pinions 61 and 61, and second pinions 62 and 62 which are rotated by the first pinions 61 and 61 and mesh with the racks 55 and 55, respectively.

When the moving member 59 is advanced by the drive source 57, the first first caulking roller 38C starts to advance. At the same time, the first pinion 61 and the second pinion 62 begin to rotate, and the left and right first caulking rollers 38L and 38R begin to move toward each other.
The three first caulking rollers 38L, 38R, and 38C are always located at the apex of an equilateral triangle having the shaft body 26 as the center of gravity (centroid).

  As a result, as shown in FIG. 6, the shaft body 26 is sandwiched between the three first caulking rollers 38L, 38R, and 38C. The first caulking rollers 38L, 38R, and 38C have a projecting outer periphery. When the shaft body 26 is turned, the first caulking rollers 38L, 38R, and 38C bite into the shaft body 26 to form a first caulking mountain.

  The second processing mechanism (23) has the same structure as the first processing mechanism 20 except that the second caulking rollers (41L, 41R, 41C) are provided. .

  As shown in FIG. 7, the pallet 35 has a plurality of through holes 64 provided at equal pitches, positioning pieces 66 and positioning pins 67 that determine the mounting position and mounting posture of the cam lobe 46 and the identification ring 65 as the first workpiece. I have. The center (FIG. 1, reference numeral 29) passes through the through hole 64.

Next, a method for manufacturing an assembly camshaft that is performed using the workpiece fastening device 10 having the above-described configuration will be described.
As shown in FIG. 8A, the shaft body 26 is inserted into the collet 27 by a robot or by hand. The shaft body 26 is suspended from the collet 27 by closing the collet 27 (reducing the diameter).
As shown in FIG. 8B, the lower portion of the shaft body 26 is positioned by the rising center 29.
As shown in FIG. 8C, the first caulking rollers 38 and 38 are bitten into the shaft body 26 while rotating the shaft body 26 at a predetermined rotational speed.

As shown in FIG. 8D, the outer periphery of the shaft body 26 is caulked and raised. As a result, a first caulking mountain 68 is formed.
As shown in FIG. 8 (e), the first caulking rollers 38, 38 are returned to the standby position, and the vicinity of the first caulking mountain 68 is opened.
As shown in FIG. 8 (f), the pallet 35 is raised and the cam lobe 46 is pressed against the first caulking mountain 68. Then, the first caulking mountain 68 is plastically deformed, and a part thereof flows into the first caulking concave portion 48 shown in FIG.

  As shown in FIG. 9, the slip torque increases in proportion to the pressing load. That is, as the pressing load increases, plastic deformation progresses, and more meat flows into the first caulking recess 48, so that slip torque increases. Assuming that the pressing load when the required torque is Ts is Fp, when the pressing load reaches Fp in FIG.

  The measurement of the pressing load is preferably performed by a load cell (for example, interposed between the cam lobe 46 and the upper surface of the pallet 35), but in this example, the current value of the third drive motor 32 is used as a load acquisition mechanism ( In FIG. 1, reference numeral 44), the pressing load is obtained by converting to the pressing load.

As shown in FIG. 10A, the pallet 35 is lowered. Since the cam lobe 46 is engaged with the first caulking mountain 68, it does not fall.
As shown in FIG. 10B, when the lower portion of the cam lobe 46 is vacant, the vicinity of the lower surface of the cam lobe 46 of the shaft body 26 is caulked by the second caulking rollers 41 and 41.
As shown in FIG. 10C, the cam lobe 46 is attached and fixed to the shaft body 26 so as to be sandwiched between the first caulking peak 68 and the second caulking peak 69.
By repeating the above, a plurality of camshaft components can be fixed to the shaft body 26.

The manufacturing method of the assembly camshaft described above can be described as follows using a flow chart. This flow is executed by the control unit (FIG. 1, reference numeral 45).
In ST01 of FIG. 11, the target position Ps related to the cam lobe is input. Where the cam lobe is provided on the shaft body is determined by a design drawing or the like, the target position Ps is uniquely determined.

  Further, in preparation for the subsequent ST17, the necessity of reworking is input and the positional deviation a allowed in actual use is input.

  In addition, the pressing target load Ls is input. The pressing target load Ls is determined from the required slip torque Ts using, for example, FIG. Furthermore, the allowable upper limit load Ls2 and the allowable lower limit load Ls1 determined from the allowable upper limit value Ts2 and the allowable lower limit value Ts1 of the slip torque permitted in actual use are input.

In ST02 of FIG. 11, the first cutting amount by the first caulking roller is input.
As shown in FIG. 13, the correlation between the depth of cut and the pressing load is examined from a large number of prototypes. Using this correlation, the cutting amount when the pressing load is Ls is determined, and this is input as the first cutting amount.
Since the first cut amount is corrected later, it is treated as an initial value in this step. Since it is an initial value, the first depth of cut is the advance distance from the time when the first caulking roller comes into contact with the outer peripheral surface of the outer diameter of the shaft body (design value. This design value does not include tolerance). That is, it is defined as the depth of cut.

In ST03 of FIG. 11, a first caulking mountain is formed on the shaft body based on the first cut amount.
Next, in ST04, the cam lobe is pressed against the first caulking mountain by the pressing mechanism.
During this pressing step, the cam lobe position information is acquired (ST05), and the pressing is continued until the cam lob reaches the target position Ps (ST06).

  When the cam lobe reaches the target position Ps, the current value of the third drive motor is measured (ST07), the third drive motor is stopped (ST08), and the current value obtained by the measurement is converted into a load (ST09). It is examined whether or not the converted load is within the allowable load range (ST10).

  If it is within the range, the cam lobe position information obtained in ST05 is acquired, and the position of the second caulking mountain is determined based on this position information (ST11). Specifically, the upper surface position of the pallet 35 can be detected by the third position sensor 43 shown in FIG. In this embodiment, since the upper surface of the pallet 35 matches the lower surface of the cam lobe 46 shown in FIG. 10C, the height position of the lower surface of the cam lobe 46 can be detected. In FIG. 10C, the position lowered by L from the lower surface of the cam lobe 46 is defined as the height of the second caulking roller. L is predetermined for each cam lobe by making an assembly camshaft and accumulating this data.

In ST12 of FIG. 11, a second caulking mountain is formed on the shaft body by the second caulking roller based on the caulking position determined.
It is checked whether or not the predetermined work is completed or the work is finished for reasons such as entering a break time or reaching the closing time (ST13). If the work is continued, the process proceeds to the next.

  In ST14, the converted load is compared with Ls (pressing target load). If the converted load is equal to or greater than Ls, correction is performed by setting (first cut amount−β) as a new first cut amount as excessive pressing (ST15). If the converted load is less than Ls, the pressing is insufficient, and (first cutting amount + β) is set as a new first cutting amount (ST16). Note that β is a value empirically selected from the range of (0.1% to 5%) of the first cut amount, for example.

The first cut amount in ST03 is replaced with the first cut amount corrected in ST15 or ST16. As a result, a first caulking mountain is formed on the next shaft body based on the first cut amount.
Since the correction by ST15 or ST16 is performed, when the pressing load fluctuates due to the change of the first caulking roller with time or the variation of the shaft body or the rod of the cam lobe, the target value is corrected and dealt with. As a result, a decrease in fastening force between the shaft body and the cam lobe can be suppressed.

If the converted load is out of the allowable load range in ST10, the necessity of reworking is examined in ST17. When it is determined that reworking is required in ST01, the process proceeds to (A), and when the result is NO, the process proceeds to ST18.
When removing the shaft body from the work fastening device using a robot and moving it to the primary storage location, acceleration force and vibration are applied, so there is a concern that the cam lobe may drop off. As a countermeasure, a second caulking mountain is formed in ST18, and then discharged as a defective product (ST19).

  When it is determined in ST10 that the converted load is out of the allowable load range, the converted load may be larger than the allowable upper limit load Ls2 or may be smaller than the allowable lower limit load Ls1. When the converted load is larger than the allowable upper limit load Ls2, there is no room for reworking, so that it is treated as a defective product. On the other hand, when it is smaller than the allowable lower limit load Ls1, there is room for rework.

  Therefore, in FIG. 14, it is checked in ST20 whether the converted load is less than the allowable lower load Ls1. That is, it is checked whether the converted load determined to be out of the allowable load range is larger than the allowable upper limit load Ls2 or smaller than the allowable lower limit load Ls1. If ST20 is negative, it is determined that the converted load is larger than the allowable upper limit load Ls2, and a second caulking peak is formed (ST21), and the defective product is discharged (ST22).

  When the converted load is less than the allowable lower load Ls1 in ST20, the third drive motor is restarted and additional pressing is performed (ST23). The current value of the third drive motor is continuously measured (ST24), the current value obtained by the measurement is converted into a load (ST25), and the obtained converted load is pressed until the target load Ls is reached. Continue driving (ST26).

When the converted load reaches the pressing target load Ls, the third drive motor is stopped (ST27), and the position of the cam lobe at that time is measured (ST28).
In ST29, it is checked whether or not the measurement position is within an allowable position range, that is, within a range of (Ps−a) to (Ps + a). a is the allowable deviation input in ST01.

If not, it is determined that the dimensions are unacceptable, so a second crimped crest is formed (ST30) and discharged as a defective product (ST31).
If the measurement position is within the allowable position range, it is determined that the rework is effective and the product has been successfully raised to the acceptable level. Therefore, the process proceeds to (B) of FIG. 11 and the flow of FIG. 11 is performed.

  The first workpiece may be a shaft and the second workpiece may be a bearing press-fitted into the shaft. Cutting (lace processing) is performed on the outer periphery of the shaft as the first workpiece with a lathe, and a bearing as the second workpiece is pressed into the processed portion to be press-fitted. If the cutting amount (cutting depth) at the time of lace processing is corrected based on the pressing load, the fastening force between the shaft and the bearing can be improved even if the wear of the cutting tool and the outer diameter of the shaft vary. Maintained properly.

Therefore, the fastening method according to the first workpiece typified by the shaft main body and the shaft and the second workpiece typified by the cam lobe and the bearing can be summarized as follows.
A first machining step (equivalent to ST03 in FIG. 11) for machining the first workpiece based on the target value, and a pressing step (equivalent to ST04 in FIG. 11) for pressing the second workpiece toward the machining location of the first workpiece; The load acquisition step (equivalent to ST09 in FIG. 11) for acquiring the pressing load in the pressing step and the target value correction step (equivalent to ST15, ST16 in FIG. 11) for correcting the target value based on the acquired load are provided. And, in the work fastening method for fastening the second work to the first work, when the target value is corrected in the target value correction step, the first machining step performed after the correction is performed, The next first workpiece is machined based on the corrected target value.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, in the above-described embodiment, the first cut amount is corrected every time. However, if the difference between the converted load and Ls (pressing target load) is less than a predetermined value, the first cut amount is not corrected. The next first workpiece may be processed with the value of.

  DESCRIPTION OF SYMBOLS 10 ... Work fastening apparatus, 20 ... 1st processing mechanism, 23 ... 2nd processing mechanism, 25 ... Pressing mechanism, 26 ... 1st workpiece | work (shaft main body), 44 ... Load acquisition mechanism, 45 ... Control part, 46 ... 2nd Work (cam lobe).

Claims (6)

A first machining step of machining a first workpiece based on a target value;
A pressing step of pressing the second workpiece toward the machining location of the first workpiece;
A load acquisition step of acquiring a pressing load in this pressing step;
A target value correcting step of correcting the target value based on an acquired load, and a work fastening method for fastening the second work to the first work,
When the target value is corrected in the target value correcting step, the first machining step performed after the correction is a workpiece fastening method in which processing is performed on the next first workpiece based on the corrected target value.   The workpiece fastening method according to claim 1, wherein the target value correcting step corrects the target value based on a pressing load when the second workpiece is pressed to a predetermined position. The first machining step is a step of caulking the outer periphery of the shaft-shaped first workpiece,
The pressing step includes inserting the first workpiece into a through hole provided in the second workpiece, and pressing an edge of the through hole of the second workpiece against the ridge formed in the first processing step. The work fastening method according to claim 2. After the pressing step, a position information acquisition step of acquiring position information of the second workpiece pressed by the pressing step, and a second processing step of processing the first workpiece based on the acquired position information. Including
The workpiece fastening method according to claim 3, wherein the second workpiece is fastened to the first workpiece between a machining location by the first machining step and a machining location by the second machining step.   The work fastening method according to any one of claims 1 to 4, wherein the first work is a shaft main body, and the second work is a cam lobe. A first machining mechanism for machining a first workpiece based on a target value;
A pressing mechanism that presses the second workpiece toward the machining location of the first workpiece;
A load acquisition mechanism for acquiring a pressing load by the pressing mechanism;
A control unit that corrects the target value based on the acquired load and applies the corrected target value to the first machining mechanism for the next first workpiece;
A work fastening device for fastening the second work to the first work.

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