Drilling equipment

Abstract

To achieve reduction of curving of a drill during processing.SOLUTION: A drill processing device (10) includes: a spindle (12) for rotating a drill (T) to process an object (O); a parallel link mechanism (18) which adjusts a direction of the spindle; a force sensor (23) which detects moments (Mx, My) around axes perpendicular to an axial direction of the spindle from the object when the object is processed; and a control unit (30) which controls the parallel link mechanism to adjust a direction of the spindle based on the moments detected by the force sensor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drilling device. [Background technology]

[0002] Drilling devices that use a drill to form a hole in a workpiece are known (see, for example, Patent Document 1). When the drill is pressed against the workpiece, the drill may wobble and bend. Such bending of the drill may cause bending of the drilled hole and even breakage of the drill. One possible solution to this problem is to use a high-strength drill that is less likely to bend or break. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-136789 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a certain limit to how much the strength of the drill itself can be improved, and it is also preferable to reduce breakage and bending even in ordinary drills that do not have improved strength.

[0005] An object of one aspect of the present invention is to provide a drilling device that reduces bending of the drill during drilling. [Means for solving the problem]

[0006] In order to solve the above problems, a drilling device according to one aspect of the present invention includes a spindle, a parallel link mechanism, a force sensor, and a control unit. The spindle rotates the drill to machine an object. The parallel link mechanism adjusts the orientation of the spindle. The force sensor detects a moment from the object around an axis perpendicular to the axial direction of the spindle while the object is being machined. The control unit controls the parallel link mechanism based on the moment detected by the force sensor to adjust the orientation of the spindle. [Effects of the Invention]

[0007] According to one aspect of the present invention, it is possible to provide a drilling device that reduces bending of the drill during drilling. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a drilling device according to an embodiment of the present invention. [Figure 2] 1 is a partial cross-sectional view illustrating a state in which a part of a drilling device according to an embodiment of the present invention is cut away. [Figure 3] FIG. 4 is a flowchart illustrating an example of an operation procedure of the drilling device. [Figure 4] FIG. 2 is a partially enlarged view showing the drilling device during cutting of an object. [Figure 5] FIG. 10 is a diagram illustrating a drilling device according to a modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment] An embodiment of the present invention will be described in detail below. Fig. 1 is a diagram showing a drilling device 10 according to an embodiment of the present invention. An XYZ coordinate system is set in which the vertical direction is the Z axis and the orthogonal directions on a plane perpendicular to the vertical direction are the X axis and the Y axis. The drilling device 10 will be described below with reference to Fig. 1.

[0010] The drilling device 10 includes a chuck 11 , a spindle 12 , a shaft 13 , a pulley 14 , a spindle holder 15 , a parallel link mechanism 18 , a mounting stay 21 , a servo cylinder 22 , a force sensor 23 , and a control unit 30 .

[0011] The chuck 11 chucks and holds the drill T. The spindle 12 is connected to the chuck 11 and is rotated by a motor and a belt via a shaft 13 and a pulley 14. As a result, the drill T is rotated and cuts an object (object to be machined) O, forming a hole H in the object O. In other words, the spindle 12 rotates the drill T to machine the object O.

[0012] The spindle holder (holding portion) 15 rotatably holds the spindle 12. Details of this will be described later.

[0013] The parallel link mechanism 18 is connected to the mounting stay 21 via a force sensor 23. The parallel link mechanism 18 holds the spindle holder 15 so that the inclination thereof is adjustable relative to the mounting stay 21. That is, the parallel link mechanism 18 adjusts the orientation of the spindle 12, ultimately the angle of the spindle 12 with respect to the object O (ultimately the angle of the drill T), via the spindle holder 15. Note that FIG. 1 shows a state in which the direction of the axis A of the spindle 12 (hereinafter also referred to as the axial direction) is aligned with the Z axis.

[0014] The mounting stay 21 is connected to the force sensor 23 and the parallel link mechanism 18, and is raised and lowered by the servo cylinder 22. The servo cylinder 22 has a cylinder mechanism and raises and lowers the mounting stay 21. As a result, the servo cylinder 22 adjusts the distance of the spindle 12 (ultimately, the drill T) relative to the object O via the mounting stay 21, the force sensor 23, the parallel link mechanism 18, and the spindle holder 15. In other words, the servo cylinder 22 functions as a distance adjustment mechanism that adjusts the distance between the spindle 12 and the object O.

[0015] Fig. 2 is a partial cross-sectional view showing a state in which a part of the drilling device 10 is cut away. Details of the drilling device 10 will be described below with reference to Fig. 2. For ease of understanding, details of the parallel link mechanism 18 are omitted in Fig. 2.

[0016] 2, the spindle 12 has members 12a to 12c. The members 12a to 12c have a generally coaxial cylindrical shape and are integrally formed. The member 12b has a larger diameter than the members 12a and 12c and is held inside the spindle holding portion 15.

[0017] The spindle holding unit 15 has a bottom member 15a, a cylindrical member 15b, lubrication mechanisms 15c and 15d, and retainers 15e and 15f. The bottom member 15a is connected to a parallel link mechanism 18, and its tilt is adjusted by the parallel link mechanism 18. The cylindrical member 15b has an inner periphery corresponding to the outer periphery of the member 12b of the spindle 12, and houses the member 12b. The lubrication mechanisms 15c and 15d are, for example, bearing mechanisms, and rotatably hold the spindle 12 (member 12b) inside the cylindrical member 15b from above and below. The retainers 15e and 15f are fixing members for holding the lubrication mechanisms 15c and 15d inside the cylindrical member 15b.

[0018] Continuing the description, returning to Figure 1, the parallel link mechanism 18 has stages 18a and 18b, multiple links 18c, multiple driving units 18d, and multiple connecting members 18e and 18f, and adjusts the orientation of the stage 18a relative to the stage 18b.

[0019] Stage 18a functions as a first stage fixed to spindle holder 15, and stage 18b functions as a second stage facing stage 18a. Stages 18a and 18b are generally ring-shaped and have openings S1 and S2 in which spindle 12 and spindle holder 15 are disposed. Openings S1 and S2 function as first and second insertion portions through which spindle 12 is inserted.

[0020] A plurality of (e.g., six) links 18c are arranged in a line and connect the stage 18a and the stage 18b via connecting members 18e and 18f. The plurality of links 18c are arranged around the outer periphery of the spindle 12 and the spindle holder 15. This prevents the operation of the parallel link mechanism 18 from interfering with the rotation of the spindle 12.

[0021] The multiple links 18c have cylindrical members 181 and rod-shaped members 182 that are slidable relative to each other, and their lengths are adjustable. By adjusting the lengths of the multiple links 18c, the orientation of stage 18a relative to stage 18b can be adjusted. The multiple links 18c connect stage 18a (first stage) and stage 18b (second stage) with a degree of freedom (here, variable length). The driver 18d drives the links 18c to change their lengths. This allows the angle between stages 18a and 18b to be adjusted using the multiple links 18c.

[0022] 2, the force sensor 23 includes a core portion 23a, a frame portion 23b, multiple beam portions 23c, multiple strain detection elements 23d, and covers 23e and 23f. The core portion 23a, frame portion 23b, and beam portions 23c together function as a strain-generating body that is distorted by stress.

[0023] The core portion 23a and the frame portion 23b are generally ring-shaped and have an opening S3 (inner circumference) in which the spindle 12 and the spindle holder 15 are disposed. The opening S3 functions as an insertion portion through which the spindle 12 is inserted. This prevents the force sensor 23 from interfering with the rotation of the spindle 12. The core portion 23a is connected to the stage 18b of the parallel link mechanism 18 via a cover 23e. The frame portion 23b is connected to the mounting stay 21 via a cover 23f. Although not shown, a gap is provided between the core portion 23a and the cover 23f to prevent force from the mounting stay 21 from being applied to the core portion 23a. Similarly, a gap is provided between the frame portion 23b and the cover 23e to prevent force from the parallel link mechanism 18 (stage 18b) from being applied to the frame portion 23b. The multiple (e.g., four) beam portions 23c are rod-shaped members that connect the core portion 23a and the frame portion 23b in a direction (radial direction) perpendicular to the axis A of the spindle 12, and deform in response to relative displacement between the core portion 23a and the frame portion 23b. The multiple strain detection elements 23d are arranged on the multiple beam portions 23c and detect strain in the multiple beam portions 23c.

[0024] The force sensor 23 detects the moment M (Mx, My, Mz) and force F (Fx, Fy, Fz) applied to the spindle 12 (applied from the object O to the drill T during machining of the object O) via the parallel link mechanism 18 and the spindle holder 15. The moments Mx, My, and Mz are moments around the X-axis, Y-axis, and Z-axis, respectively, and the forces Fx, Fy, and Fz are forces in the X-axis, Y-axis, and Z-axis directions, respectively. Here, the moments Mx and My refer to moments around axes perpendicular to the direction of the axis A of the spindle 12. The moment Mz refers to a moment around the axis A of the spindle 12. The force Fz refers to a force in the axial direction of the spindle 12.

[0025] The control unit 30 performs the following control in accordance with the moment M and force F detected by the force sensor 23.

[0026] The control unit 30 controls the parallel link mechanism 18 based on the moments Mx and My to adjust the orientation of the spindle 12. This reduces bending of the drill T during machining. More specifically, when the moments Mx and My become equal to or greater than the threshold value Th1, the control unit 30 controls the parallel link mechanism 18 so that the moments Mx and My are reduced (become smaller than the threshold value Th1). This allows the moments to be reduced based on the threshold value.

[0027] The control unit 30 controls the servo cylinder 22 based on the force Fz to adjust the distance between the spindle 12 and the object O. This prevents damage to the drill T due to clogging of chips, etc. More specifically, when the force Fz becomes equal to or greater than the threshold value Th2, the control unit 30 controls the servo cylinder 22 to reduce the force Fz (to make it smaller than the threshold value Th2). This allows the force to be reduced based on the threshold value Th2.

[0028] The control unit 30 controls the servo cylinder 22 based on the moment Mz to adjust the distance between the spindle 12 and the object O. This prevents damage to the drill due to chip clogging or the like. More specifically, when the moment Mz becomes equal to or greater than the threshold value Th3, the control unit 30 controls the servo cylinder 22 to reduce the moment Mz (to make it smaller than the threshold value Th3). This allows the moment around the axis of the spindle 12 to be reduced based on the threshold value Th3.

[0029] The following describes the operation of the drilling device 10. Figure 3 is a flow chart showing an example of the operation procedure of the drilling device 10.

[0030] The drilling device 10 is activated and starts drilling (step S1). That is, the drilling device 10 holds and rotates a drill T to form a hole H in an object O. At this time, a moment M and a force F are applied from the object O to the drill T.

[0031] The moments Mx and My can be generated, for example, when the drill T is not perfectly perpendicular to the object O, or when there is some non-uniformity (for example, non-uniformity in the material or surface shape of the object O).

[0032] The force sensor 23 detects the moment M and the force F applied to the spindle 12 (step S2). Ultimately, the moment M (Mx, My, Mz) and the force F (Fx, Fy, Fz) applied from the object O to the drill T are detected.

[0033] Of these, moments Mx and My can cause bending of the drill T, and even bending of the hole H, and breakage of the drill T. Moments Mx and My are particularly likely to become a problem when (1) deepening the hole H or (2) forming a small-diameter hole H. When deepening the hole H, a long drill T is used, and bending of the drill T due to moments Mx and My increases. When forming a small-diameter hole H, a thin drill T (e.g., φ0.2 mm, φ0.01 mm) is used, and bending of the drill T due to moments Mx and My increases.

[0034] FIG. 4 is a partially enlarged view showing the drilling device during cutting of the object O. While cutting the object O, the drill T is bent due to a moment My. The tip of the bent drill T has an angle θ with respect to the axis A of the spindle 12 (the original axis of the drill T). As the hole H is drilled, the angle θ increases, and the drill T reaches its bending limit, causing it to break.

[0035] In this way, slight defects at the beginning of machining (slight non-orthogonality of the drill T to the object O, slight non-uniformity of the object O) can cause the moments Mx and My. As a result, the drill T can bend, and if the bending is not corrected, it can lead to a major defect (for example, breakage of the drill T). In such cases, the drilling device 10 of this embodiment reduces the bending of the drill T to prevent the occurrence of a major defect.

[0036] Therefore, the control unit 30 determines whether the moments Mx and My are equal to or greater than a predetermined threshold value Th1 (Mx, My≧Th1) (step S3), and if the determination is YES, controls the parallel link mechanism 18 to adjust the orientation of the spindle 12 (step S3). As a result, the moments Mx and My are reduced, and bending of the drill T is reduced. As a result, damage to the drill T can be prevented.

[0037] Furthermore, if such control is performed from the beginning of machining, it becomes easier to maintain the drill T in a straight state at all times. In this case, bending of the hole H is reduced. In other words, it becomes easier to maintain the angle θ in FIG. 4 close to 0, which can contribute to improving machining accuracy.

[0038] Furthermore, the control unit 30 determines whether the force Fz and moment Mz are equal to or greater than predetermined thresholds Th2 and Th3 (Fz≧Th2, Mz≧Th3) (step S5), and if the determination is YES, controls the servo cylinder 22 to adjust the distance between the spindle 12 and the object O (ultimately, the amount of depression of the spindle 12) (step S6). As a result, the force Fz and moment Mz are reduced, and damage to the drill T can be prevented.

[0039] The force Fz and moment Mz are generated, for example, when the drill T comes into contact with chips. If the drill T comes into contact with chips stuck in the hole H and a large force Fz and moment Mz are applied, there is a risk that the drill T may break. In particular, the force Fz and moment Mz are likely to become a problem when it is desired to deepen the hole H. As the hole H deepens, the chips formed during cutting tend to become stuck in the hole H.

[0040] For ease of understanding, an example is shown in which control based on moments Mx and My and control based on force Fz and moment Mz are performed in that order. This order may be reversed, or the controls may be performed simultaneously.

[0041] As described above, in this embodiment, the moments Mx and My applied to the spindle 12 are set smaller than the threshold value Th1, thereby reducing bending of the drill T and ultimately preventing damage to the drill T. Furthermore, by reducing bending of the drill T from the beginning of machining, the straightness (machining accuracy) of the hole H to be formed is improved.

[0042] Furthermore, in this embodiment, the force Fz and moment Mz applied to the spindle 12 are set smaller than the threshold values ​​Th2 and Th3, respectively, so that damage to the drill T due to clogging of chips can be prevented.

[0043] (Variation) A drilling device 10 according to a modified example will be described below. Fig. 5 is a diagram showing a drilling device 10 according to a modified example of the present invention. In the drilling device 10 according to the modified example, the mounting stay 21 is bent and divided into members 21a, 21b, and 21c, and member 21b is disposed vertically between the spindle holding portion 15 and the servo cylinder 22. As a result, the distance between the spindle holding portion 15 and the servo cylinder 22 is reduced, making the drilling device 10 more compact.

[0044] In the embodiment, when the moment Mz and the force Fz are equal to or greater than the threshold values ​​Th2 and Th3, the control unit 30 controls the servo cylinder 22. Alternatively, the operation of the servo cylinder 22 may be stopped to prevent the spindle 12 (drill T) from being pushed further in. Also, a warning may be issued to the operator of the drilling device 10 by emitting sound or light using a sound output device or a display device.

[0045] In the embodiment, the length of the link 18c is adjustable, but it may be bendable. In this case, the orientation of the stage 18a relative to the stage 18b can be adjusted by adjusting the angle at which the link 18c is bent.

[0046] In the embodiment, the force sensor 23 is disposed between the mounting stay 21 and the parallel link mechanism 18, but it may be disposed in another location. The force sensor 23 can be disposed on the path from the drill T to the mounting stay 21 via the spindle 12, the spindle holder 15, and the parallel link mechanism 18, for example, between the spindle holder 15 and the parallel link mechanism 18.

[0047] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0048] 10... Drilling device, 12 Spindle, 15... Spindle holder, 18... Parallel link mechanism, 22... Servo cylinder, 23... Force sensor, 30... Control unit

Claims

1. a spindle for rotating the drill to process the object; a parallel link mechanism for adjusting the orientation of the spindle; a force sensor that detects a moment applied to the spindle about an axis perpendicular to the axial direction of the spindle; a control unit that controls the parallel link mechanism based on the moment detected by the force sensor to adjust the orientation of the spindle; Equipped with The force sensor has an insertion portion through which the spindle is inserted.

2. the control unit controls the parallel link mechanism so as to reduce the moment when the moment is equal to or greater than a predetermined threshold value. The drilling device according to claim 1 .

3. a holding portion that rotatably holds the spindle, The parallel link mechanism includes: a first stage fixed to the holding portion; a second stage facing the first stage; a plurality of links connecting the first stage and the second stage with degrees of freedom; a drive unit that drives the plurality of links, 3. The drilling device according to claim 1 or 2.

4. the first stage has a first insertion portion through which the spindle is inserted, the second stage has a second insertion portion through which the spindle is inserted, the plurality of links are disposed around the spindle; The drilling device according to claim 3.

5. a distance adjustment mechanism for adjusting the distance between the spindle and the object; the force sensor detects a force in an axial direction of the spindle; The control unit controls the distance adjustment mechanism based on the force to adjust the distance between the spindle and the object. A drilling device according to any one of claims 1 to 4.

6. When the force is equal to or greater than a predetermined threshold, the control unit controls the distance adjustment mechanism so as to reduce the force. The drilling device according to claim 5.

7. a distance adjustment mechanism for adjusting the distance between the spindle and the object; the force sensor detects a moment around an axis of the spindle; The control unit controls the distance adjustment mechanism based on a moment about the axis of the spindle to adjust the distance between the spindle and the object. A drilling device according to any one of claims 1 to 6.

8. the control unit controls the distance adjustment mechanism so that the moment about the axis of the spindle is reduced when the moment about the axis of the spindle is equal to or greater than a predetermined threshold. The drilling device according to claim 7.

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