Burnishing device and burnishing method

Abstract

To provide a burnishing device that can burnish an inner peripheral surface of a machined hole of a metal work-piece into a smooth surface with high precision, without rotating a burnishing tool, which can eliminate necessity for managing a rotation speed of the burnishing tool and also can elongate a service life of the burnishing tool.SOLUTION: The burnishing device is provided with a burnishing tool 12 that burnishes an inner peripheral surface of a cylindrical machined hole Wa formed in a metal work-piece W, and a tool driving machine that can apply a burnishing process A and a returning process B to the burnishing tool 12 along an axial direction thereof, while supporting a spindle 12a of the burnishing tool 12 unrotatably. In the burnishing tool 12 are provided sequentially an annular first burnishing tip 14 and an annular second burnishing tip 15 whose entire peripheral surfaces from tip sides thereof are smooth surfaces which are harder than the metal work-piece W, and an outer diameter D2 of the second burnishing tip 15 is set to be larger than an outer diameter D1 of the first burnishing tip 14.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a burnishing device and a burnishing method for burnishing the inner surface of a cylindrical machining hole provided in a metal workpiece. [Background technology]

[0002] Conventionally, a known burnishing device, as described in Patent Document 1, includes a burnishing tool having a grinding tip on the outer periphery of its tip, for burnishing the inner surface of a cylindrical machining hole provided in a metal workpiece, a support base that fixes and supports the metal workpiece so as to position the machining hole coaxially with the burnishing tool, a drive unit that, while rotating the burnishing tool, can give the burnishing tool a forward stroke for burnishing the machining hole along its axial direction and a return stroke after the burnishing, and a stripper that is disposed between the drive unit and the metal workpiece fixedly supported on the support base, and that receives the metal workpiece on the return stroke of the burnishing tool, causing the burnishing tool to separate from the machining hole, [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6647664 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional burnishing device described above, when burnishing the inner surface of a machining hole in a metal workpiece, a burnishing tool having a grinding tip at its tip is rotated and moved axially. Therefore, in order to maintain high dimensional accuracy and surface roughness of the machining hole, strict adjustment and control of the rotation speed of the burnishing tool is required, and the burnishing tool has a short lifespan, which results in high machining costs.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a burnishing device and a burnishing method that can burnish the inner surface of a machined hole in a metal workpiece to a highly accurate smooth surface without rotating the burnishing tool, thereby eliminating the need to manage the rotational speed of the burnishing tool and extending the life of the burnishing tool. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides: A burnishing device comprising: a burnishing tool for burnishing the inner peripheral surface of a cylindrical machining hole provided in a metal workpiece; a tool driving machine for applying a burnishing stroke and a return stroke to the burnishing tool along its axial direction while supporting a main shaft of the burnishing tool so as not to rotate; a support table for fixedly supporting the metal workpiece coaxially with the burnishing tool so that the inner peripheral surface of the machining hole can be burnished by the burnishing stroke of the burnishing tool; and a stopper for restricting movement of the metal workpiece during the return stroke of the burnishing tool after the burnishing of the inner peripheral surface of the machining hole has been completed, thereby causing the burnishing tool to separate from the metal workpiece, A holder (21) capable of holding the metal workpiece (W) whose movement is restricted by the stopper (18) during the return stroke (B) of the burnishing tool (12) is provided adjacent to the stopper (18), and The first feature of the burnishing tool is that a first annular burnishing tip and a second annular burnishing tip are sequentially provided on the main shaft of the burnishing tool from the tip side, each having an entire circumferential surface that is smooth and harder than the metal workpiece, and the outer diameter of the second burnishing tip is set larger than the outer diameter of the first burnishing tip.

[0007] In addition to the first feature, the present invention has a second feature in that both axial end portions of the first and second burnishing tips are formed into tapered surfaces.

[0009] The present invention also provides When burnishing the inner surface of a cylindrical machining hole provided in a metal workpiece, a burnishing tool comprising a spindle having a first annular burnishing tip and a second annular burnishing tip sequentially provided on the spindle from the tip end side thereof, each of which has an entire circumferential surface that is smooth and harder than the metal workpiece, and the second burnishing tip has an outer diameter that is set larger than the outer diameter of the first burnishing tip; a tool driver that can apply a burnishing stroke and a return stroke to the burnishing tool along its axial direction while supporting the main shaft of the burnishing tool so that it cannot rotate; 、 a stopper that restricts movement of the metal workpiece during the return stroke to cause the burnishing tool to separate from the metal workpiece; a holder provided adjacent to the stopper and capable of holding the metal workpiece whose movement is restricted by the stopper during the return stroke of the burnishing tool; Prepare a step of fixing and supporting the metal workpiece on a support table so as to position the processing hole coaxially with the burnishing tool; a step of applying the burnishing process to the burnishing tool by the tool driving machine, and burnishing the inner circumferential surface of the machined hole from one end to the other end thereof by the first and second burnishing tips; After the burnishing process, when the tool driving machine gives the burnishing tool (12) a return stroke (B), the movement of the metal workpiece is The stopper restrain , holding the restrained metal workpiece with the holding device; and and a step of detaching the burnishing tool from the metal workpiece. Third The characteristics of this product are as follows: [Effects of the Invention]

[0010] According to the first feature of the present invention, by performing a burnishing process and a return process on a burnishing tool having first and second burnishing tips that are harder than the metal workpiece without rotating it, the inner surface of a machined hole in the metal workpiece can be finished into a highly smooth surface.This eliminates the need to manage the rotational speed of the burnishing tool and extends the life of the burnishing tool, which can contribute to reducing processing costs.

[0011] According to the second feature of the present invention, it is possible to prevent the burnishing tools from galling the inner peripheral surface of the machining hole during the burnishing stroke and return stroke of the burnishing tools.

[0012] According to a third feature of the present invention, when the movement of the metal workpiece is restricted by a stopper in order to remove the burnishing tool from the machining hole of the metal workpiece during the return stroke of the burnishing tool, the metal workpiece is held by a holding device, thereby preventing damage to the metal workpiece from falling when the burnishing tool is removed.

[0013] The fourth feature of the present invention also makes it possible to finish the inner surface of a machined hole in a metal workpiece into a highly smooth surface, thereby eliminating the need to control the rotational speed of the burnishing tool and extending the life of the burnishing tool, which can contribute to reducing processing costs. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a front view of a burnishing device according to the present invention, showing the state before burnishing a metal workpiece. [Figure 2] This is a diagram corresponding to Figure 1, showing the state during burnishing. [Figure 3] This is a diagram corresponding to Figure 1, showing the state immediately after burnishing. [Figure 4] This is a corresponding diagram to Figure 1, showing the state in which the burnishing tool has been removed from the metal workpiece after burnishing. [Figure 5] Cross-sectional view taken along line 5-5 in Figure 4. [Figure 6] Enlarged view of part 6 of Figure 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0016] First, in FIG. 1, a burnishing device 10 is used to finish the inner circumferential surface of a cylindrical machining hole Wa provided in a metal workpiece W into a highly smooth surface.

[0017] This burnishing device 10 comprises a burnishing tool 12 that burnishes the inner surface of the machining hole Wa of a metal workpiece W, a tool driver 16 that holds the main shaft 12a of the burnishing tool 12 non-rotatably with a head 16a and can drive it up and down along the axial direction, a support base 17 that fixedly supports the metal workpiece W with a positioning hole 17a below the burnishing tool 12 held by the head 16a and positions the machining hole Wa coaxially with the burnishing tool 12, and a stopper 18 that is installed directly above the metal workpiece W on the support base 17 and allows the burnishing tool 12 to pass but prevents the metal workpiece W from rising above a certain level. Reference numeral 20 denotes an opening provided in an upper wall 18a of the stopper 18, which allows the burnishing tool 12 to pass but prevents the metal workpiece W from rising above a certain level with the underside of the upper wall 18a around the opening 20.

[0018] 4 and 5, the burnishing device 10 further includes a holder 21 disposed directly below the upper wall 18a of the stopper 18. The holder 21 is made up of a plurality of holder arms 21a (three in the illustrated example) arranged radially around the axis of the burnishing tool 12, and these holder arms 21a are interlocked with one another by the operation of an interlocking drive means (not shown), so that they can advance and retreat toward the axis and hold or release the metal workpiece W. The side wall 18b of the stopper 18 is provided with a through hole 22 through which the holder arms 21a pass, and a workpiece entrance / exit 23 for the metal workpiece W.

[0019] When the burnishing tool 12 is subjected to a burnishing process A (a downward process in the illustrated example) by driving the head 16a of the tool driver 16 forward, the burnishing tool 12 burnishes the inner surface of the machining hole Wa of the metal workpiece W as it moves from its upper end to its other end, as shown in Figure 2, and reaches the completed machining state shown in Figure 3.

[0020] After the burnishing process, when the head 16a of the tool driver 16 is driven backward to give the burnishing tool 12 a return stroke B (an upward stroke in the illustrated example), as shown in Figure 4, the metal workpiece W rises slightly together with the burnishing tool 12 and comes out of the positioning hole 17a of the support base 17, but immediately thereafter it abuts against the upper wall 18a of the stopper 18 and is prevented from rising any further.

[0021] At this time, all the holding arms 21a are advanced by the operation of the holding machine 21, and they press and hold the outer peripheral surface of the metal workpiece W.

[0022] As a result, the burnishing tool 12 comes out of the machining hole Wa of the metal workpiece and returns to its initial position. Meanwhile, the metal workpiece W, which is restrained from rising by the upper wall 18a of the stopper 18, has its outer peripheral surface pressed and held by the multiple holding arms 21a, so damage caused by the metal workpiece W falling onto the support base 17, particularly damage to the burnished inner peripheral surface of the metal workpiece W, can be prevented.

[0023] The metal workpiece W held by the holding arm 21a is removed by a robot arm (not shown) through the workpiece entrance / exit 23 in the side wall 18b of the stopper 18. At this time, it goes without saying that the holding arm 21a retreats and releases the metal workpiece W.

[0024] Next, the burnishing tool 12 will be described in detail with reference to FIG.

[0025] The burnishing tool 12 has a first annular burnishing tip 14 and a second burnishing tip 15 sequentially provided on its main shaft 12a from the tip end, each of which has an entire circumferential surface that is smooth and harder than the metal workpiece W, and the outer diameter D2 of the second burnishing tip 15 is set larger than the outer diameter D1 of the first burnishing tip 14. Naturally, the first burnishing tip 14 is set larger than the inner diameter of the machining hole Wa. Furthermore, the front and rear ends of each burnishing tip 14, 15 are formed into a pair of tapered surfaces 14a, 14b; 15a, 15b.

[0026] 2, when the tool driver 16 applies the burnishing process A to the burnishing tool 12, the burnishing tool 12 is forced into the machining hole Wa of the metal workpiece W without rotating. Then, as shown in Fig. 6, first, the first burnishing tip 14, which has a larger diameter than the machining hole Wa and a higher hardness than the metal workpiece W, moves while squeezing the rough inner peripheral surface F0 of the machining hole Wa, thereby imparting plastic deformation to the rough inner peripheral surface F0 to form a primary finished surface F1, and then the second burnishing tip 15, which also has a high hardness and a larger diameter than the first burnishing tip 14, moves while squeezing the primary finished surface F1, thereby imparting further plastic deformation to the primary finished surface F1 to form a highly accurate and smooth secondary finished surface F2.

[0027] By performing this burnishing process from one end of the machined hole Wa in the metal workpiece W to the other (see Figure 3), the rough inner peripheral surface F0 of the machined hole Wa can be finished into a highly accurate smooth surface F2, as described above. Moreover, since the burnishing tool 12 is used in a non-rotating state, there is no need to manage the rotational speed of the burnishing tool 12. Furthermore, since the plastic deformation imparted to the rough inner peripheral surface F0 of the machined hole Wa is sequentially performed by the first and second burnishing tips 14, 15, the processing load on each burnishing tip 14, 15 of each burnishing tool 12 is reduced, not only maintaining the durability of each tip, but also reducing the load on the tool driver 16. As a result, it is possible to reduce the cost of burnishing the metal workpiece W.

[0028] In addition, the pairs of tapered surfaces 14a, 14b; 15a, 15b provided at the front and rear ends of the first and second burnishing tips 14, 15 are extremely effective in preventing the burnishing tips 14, 15 from biting into the inner surface of the machining hole Wa during the burnishing processing stroke A and return stroke B of the burnishing tool 12.

[0029] The present invention is not limited to the above-described embodiment, and various design modifications are possible within the scope of the gist of the present invention.

[0030] For example, in the burnishing tool 12, third, fourth, etc. burnishing tips with successively increasing outer diameters can be added to the spindle 12a behind the second burnishing tip 15. Also, the tapered surfaces 14a, 14b; 15a, 15b of each burnishing tip 14, 15 may have different taper angles at the front and rear. Also, the burnishing processing device 10 can be configured to be horizontally placed so that the burnishing tool 12 can be moved horizontally. [Explanation of symbols]

[0031] A. Burnishing process B... Return stroke W...Metal workpiece Wa... Machining hole 10. Burnishing equipment 12 Burnishing tool 14. First burnishing tip 14a: Tapered surface on the front end side of the first burnishing tip 14b Tapered surface on the rear end side of the first burnishing tip 15. Second burnishing tip 15a: Tapered surface on the front end side of the second burnishing tip 15b Tapered surface on the rear end side of the second burnishing tip 18 Stopper 21...Holding machine

Claims

1. A burnishing tool (12) for burnishing the inner peripheral surface of a cylindrical machining hole (Wa) provided in a metal workpiece (W), a tool driver (16) for non-rotatably supporting a main shaft (12a) of the burnishing tool (12) and for applying a burnishing stroke (A) and a return stroke (B) to the burnishing tool (12) along its axial direction, and a burnishing tool (12) for burnishing the inner peripheral surface of the machining hole (Wa) by the burnishing stroke (A) of the burnishing tool (12). a support table (17) for fixedly supporting the metal workpiece (W) coaxially with the burnishing tool (12) so that the metal workpiece (W) can be burnished; and a stopper (18) for restricting the movement of the metal workpiece (W) during the return stroke (B) of the burnishing tool (12) after the burnishing of the inner peripheral surface of the processing hole (Wa) has been completed, thereby causing the burnishing tool (12) to separate from the metal workpiece (W), A holder (21) capable of holding the metal workpiece (W) whose movement is restricted by the stopper (18) during the return stroke (B) of the burnishing tool (12) is provided adjacent to the stopper (18), A burnishing device characterized in that a first annular burnishing tip (14) and a second burnishing tip (15) are sequentially provided on the main shaft (12a) of the burnishing tool (12) from the tip side, each having an entire circumferential surface that is smooth and harder than the metal workpiece (W), and the outer diameter (D2) of the second burnishing tip (15) is set larger than the outer diameter (D1) of the first burnishing tip (14).

2. 2. The burnishing device according to claim 1, wherein both axial ends of the first and second burnishing tips (14, 15) are formed with tapered surfaces (14a, 14b; 15a, 15b).

3. When burnishing the inner peripheral surface of a cylindrical machining hole (Wa) provided in a metal workpiece (W), a burnishing tool (12) comprising a main shaft (12a) and an annular first burnishing tip (14) and a second burnishing tip (15) sequentially provided on the main shaft (12a) from the tip side thereof, each having an entire circumferential surface that is smooth and harder than the metal workpiece (W), and an outer diameter (D2) of the second burnishing tip (15) set larger than an outer diameter (D1) of the first burnishing tip (14); a tool driver (16) that can apply a burnishing stroke (A) and a return stroke (B) to the burnishing tool (12) along its axial direction while supporting the main shaft (12a) of the burnishing tool (12) so as not to rotate; a stopper (18) that restricts the movement of the metal workpiece (W) during the return stroke (B) to cause the burnishing tool (12) to separate from the metal workpiece (W); a holder (21) provided adjacent to the stopper (18) and capable of holding the metal workpiece (W) whose movement is restricted by the stopper (18) during the return stroke (B) of the burnishing tool (12); a step of fixing and supporting the metal workpiece (W) on a support table (17) so as to position the processed hole (Wa) coaxially with the burnishing tool (12); a step of applying the burnishing process (A) to the burnishing tool (12) by the tool driving machine (16) to burnish the inner peripheral surface of the machining hole (Wa) from one end to the other end thereof by the first and second burnishing tips (14, 15); This burnishing method is characterized by sequentially carrying out the steps of: after the burnishing step, when the burnishing tool (12) is given a return stroke (B) by the tool driving machine (16), restraining the movement of the metal workpiece (W) with the stopper (18), holding the restrained metal workpiece (W) with the holding machine (21), and detaching the burnishing tool (12) from the metal workpiece (W).

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