JP7737962B2 - Burnishing device and burnishing method - Google Patents

Description

The present invention relates to a burnishing device and burnishing method for burnishing the inner surface of a cylindrical machining hole in a metal workpiece.

A known burnishing device, as described in Patent Document 1, includes a burnishing tool with a grinding tip on the outer periphery of its tip, for burnishing the inner surface of a cylindrical hole in a metal workpiece; a support base that fixes and supports the metal workpiece so that the hole is positioned coaxially with the burnishing tool; a drive unit that rotates the burnishing tool and causes the burnishing tool to perform a forward stroke along its axial direction to burnish the hole and a return stroke after burnishing; and a stripper that is disposed between the drive unit and the metal workpiece fixedly supported on the support base and receives the metal workpiece during the return stroke of the burnishing tool, causing the burnishing tool to separate from the hole.

Patent No. 6647664

With conventional burnishing equipment, when burnishing the inner surface of a machined hole in a metal workpiece, a burnishing tool with an abrasive tip at its tip is rotated and moved axially. Therefore, to maintain high dimensional accuracy and surface roughness of the machined hole, the burnishing tool's rotational speed must be precisely adjusted and controlled. Additionally, the burnishing tool has a short lifespan, resulting in high processing costs.

The present invention was made in light of these circumstances, and aims to provide a burnishing device and burnishing method that can burnish the inner surface of a machined hole in a metal workpiece to a highly 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.

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),
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.

In addition to the first feature, the present invention has a second feature in that both axial ends of the first and second burnishing tips are formed with tapered surfaces.

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, a first annular burnishing tip and a second annular burnishing tip provided in this order from the tip end side thereof, each having an entire circumferential surface formed into a smooth surface having a higher hardness than the metal workpiece, and the second burnishing tip having an outer diameter larger than that of the first burnishing tip;
a tool driving machine capable of applying 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 as not to 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 that is provided adjacent to the stopper and that can hold the metal workpiece whose movement is restricted by the stopper during the return stroke of the burnishing tool ;
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;
A third feature of the present invention is that, after the burnishing process, when the burnishing tool (12) is given a return stroke (B) by the tool driving machine, the process of restraining the movement of the metal workpiece with the stopper , holding the restrained metal workpiece with the holding machine, and detaching the burnishing tool from the metal workpiece is carried out in this order.

According to a first aspect of the present invention, by performing a burnishing stroke and a return stroke without rotating a burnishing tool having first and second burnishing tips that are harder than the metal workpiece, 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, potentially contributing to reduced processing costs.

The second feature of the present invention makes it possible to prevent the burnishing tool from galling the inner surface of the hole during the burnishing stroke and return stroke of the burnishing tool.

According to a third feature of the present invention, when the movement of the metal workpiece is restricted by a stopper to remove the burnishing tool from the work hole in the metal workpiece during the return stroke of the burnishing tool, the metal workpiece is held by a holder, thereby preventing damage to the metal workpiece from falling when the burnishing tool is removed.

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

1 is a front view of a burnishing device according to the present invention, showing a state before burnishing a metal workpiece. This is a diagram corresponding to Figure 1, showing the state during burnishing. This is a diagram corresponding to Figure 1, showing the state immediately after burnishing. 1 , showing the state in which the burnishing tool has been removed from the metal workpiece after burnishing. Cross-sectional view taken along line 5-5 in Figure 4. FIG. 6 is an enlarged view of part 6 of FIG. 2 .

Embodiments of the present invention are described below with reference to the accompanying drawings.

First, in Figure 1, the burnishing device 10 is used to finish the inner surface of a cylindrical machining hole Wa in a metal workpiece W into a highly smooth surface.

This burnishing device 10 includes a burnishing tool 12 that burnishes the inner surface of the machining hole Wa in the metal workpiece W; a tool driver 16 that non-rotatably holds the main shaft 12a of the burnishing tool 12 with a head 16a and can drive it up and down along the axial direction; a support table 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 installed directly above the metal workpiece W on the support table 17, which allows the burnishing tool 12 to pass through but prevents the metal workpiece W from rising above a certain level. Reference numeral 20 denotes an opening provided in the upper wall 18a of the stopper 18, which allows the burnishing tool 12 to pass through but prevents the metal workpiece W from rising above a certain level with the underside of the upper wall 18a around the opening 20.

As shown in Figures 4 and 5, the burnishing device 10 further includes a holder 21 disposed directly below the upper wall 18a of the stopper 18. This holder 21 consists of multiple holder arms 21a (three in the illustrated example) arranged radially around the axis of the burnishing tool 12. These holder arms 21a are interlocked with one another and move forward and backward toward the axis by the operation of an interlocking drive means (not shown), thereby holding and releasing 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.

When the head 16a of the tool driver 16 is driven forward to perform the burnishing process A (the downward process in the illustrated example) on the burnishing tool 12, as shown in Figure 2, the burnishing tool 12 burnishes the inner surface of the hole Wa in the metal workpiece W as it moves from its upper end to its other end, resulting in the completed processing state shown in Figure 3.

After burnishing, 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), the metal workpiece W rises slightly together with the burnishing tool 12, as shown in Figure 4, and comes out of the positioning hole 17a in the support table 17. However, immediately afterwards, it abuts against the upper wall 18a of the stopper 18, preventing further rise.

At that time, the holder 21 is activated to move all of the holding arms 21a forward, which press against and hold the outer surface of the metal workpiece W.

As a result, the burnishing tool 12 comes out of the machining hole Wa in 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 surface pressed and held by the multiple holding arms 21a, preventing damage caused by the metal workpiece W falling onto the support table 17, particularly damage to the burnished inner surface of the metal workpiece W.

The metal workpiece W held by the holding arm 21a is removed by a robot arm (not shown) through the workpiece inlet/outlet 23 in the side wall 18b of the stopper 18. At this time, the holding arm 21a naturally retracts to release the metal workpiece W.

Next, the burnishing tool 12 will be explained in more detail with reference to Figure 6.

The burnishing tool 12 has a first annular burnishing tip 14 and a second annular burnishing tip 15 mounted on its main shaft 12a, each of which has a smooth surface with a higher hardness than the metal workpiece W along its entire periphery. 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.

2, when the tool driver 16 applies burnishing stroke A to the burnishing tool 12, the burnishing tool 12 is forced into the hole Wa in the metal workpiece W without rotating. Then, as shown in FIG. 6, first, the first burnishing tip 14, which is larger in diameter than the hole Wa and harder than the metal workpiece W, rubs and moves against the rough inner surface F0 of the hole Wa, plastically deforming the rough inner surface F0 to form a primary finished surface F1. Next, the second burnishing tip 15, which is also hard and has a larger diameter than the first burnishing tip 14, rubs and moves against the primary finished surface F1, further plastically deforming the primary finished surface F1 to form a highly accurate, smooth secondary finished surface F2.

By performing this burnishing process from one end of the hole Wa in the metal workpiece W to the other (see Figure 3), the rough inner surface F0 of the hole Wa can be finished into a highly smooth surface F2, as described above. Furthermore, because 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, because the plastic deformation imparted to the rough inner surface F0 of the hole Wa is carried out sequentially 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 metal workpieces W.

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 galling the inner surface of the machining hole Wa during the burnishing stroke A and return stroke B of the burnishing tool 12.

The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit of the invention.

For example, in the burnishing tool 12, third, fourth, etc. burnishing tips with successively increasing outer diameters can be attached to the spindle 12a behind the second burnishing tip 15. Furthermore, the tapered surfaces 14a, 14b; 15a, 15b of each burnishing tip 14, 15 may have different taper angles at the front and rear. The burnishing device 10 can also be configured horizontally to allow the burnishing tool 12 to move horizontally.

A: Burnishing process B: Return process W: Metal workpiece Wa: Machining hole 10: Burnishing device 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 device

Claims (3)

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