JP2725423B2 - Roller burnishing machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller burnishing machine that performs surface finishing by pressing a roller against the surface of a rotating work.

2. Description of the Related Art For example, grinding and lapping are often performed as a surface finishing method for a cylindrical work that has been subjected to a cutting process.In such polishing and lapping, a work surface is ground by a grindstone or a lapping material and the surface is smoothed. For example, when the main journal portion of the crankshaft is surface-finished by this polishing or lapping method, according to the current technology, the surface roughness is approximately 0.6%.
It can be finished to about 0.4μmRZ. As a method of improving the surface roughness, for example, various methods such as a super lapping technology and a buff polishing technology are known, and many new technologies are being developed.

On the other hand, there is a roller burnishing method as a method of finishing without shaving the work surface. This roller burnishing method is already used as a method of finishing a center frust surface of a crankshaft, a fork groove of a hub sleeve, and the like, and is mainly used to omit a polishing process after turning. If this roller burnishing method is applied to the method of finishing the surface of the crankpin and crank journal of the crankshaft, the surface roughness is improved to improve the seizure resistance of the pin and journal, and the pin and journal are improved. It is possible to withstand a higher load, and it is possible to reduce the weight of the engine and reduce frictional horsepower (a value of work consumed inside the engine in horsepower).

In the conventional roller burnishing method, a small-diameter roller is pressed into contact with a turning surface of a rotating work, and the surface is smoothed. That is, it is general that the processing load is constant.

Problems to be Solved by the Invention However, as in the conventional roller burnishing method described above, when processing is performed with a constant pressing force of the roller against the work surface, for example, when the work is a crankshaft, In the case of a perforated shaft having an oil hole on the surface to be finished, the contact area of the roller at the oil hole decreases, and the surface pressure on the contact line including the oil hole increases. As a result, there is a problem that the work surface is further depressed at the contact line portion including the oil hole, thereby deteriorating the roundness of the work. FIG. FIG. That is, the vertical axis and the horizontal axis have a length (μm) for representing the depression depth of the surface of the work, and only the portion corresponding to the oil hole position is deeply depressed.

The present invention has been made in view of the above circumstances, and has as its object to provide a roller burnishing machine capable of greatly improving the surface roughness without deteriorating the roundness of a work.

Means for Solving the Problems As means for solving the above-mentioned problems, the present invention provides a roller burnishing machine that presses a roller against a surface to be processed of a rotating work to smooth the surface to be processed. A burnishing roller that rolls by pressing against the work surface, a backup roller that receives the reaction force of the pressing force of the burnish roller via the work, and a unit that presses the burnish roller against the work surface of the work,
And a pressing force control means for reducing a pressing force of the burnishing roller when the burnishing roller approaches a specific portion on the surface to be processed.

Operation With the configuration described above, the vanishing roller is pressed against the processing surface of the rotating work by the pressing means, and the processing surface is processed smoothly. At this time,
For example, when the workpiece is a perforated shaft such as a crankshaft having an oil hole, the vanish roller has approached a specific location based on the rotational position of the specific location such as the oil hole and the amount of rotation of the workpiece. Is detected, and the pressing force of the vanish roller is reduced based on this. That is, the surface pressure on a specific portion such as an oil hole is reduced, and deformation such as excessive depression at that portion is prevented.

Embodiment Hereinafter, as an embodiment of a roller burnishing machine of the present invention, a case where a journal portion of a crankshaft which has been lap-finished after polishing is further subjected to burnishing will be described with reference to FIGS. 1 to 6. explain.

The roller burnishing machine 1 includes a processing unit 1a and a control unit 1b. The processing unit 1a includes a frame 2 formed by punching a flat plate into a substantially U-shape, and two sides of the U-shaped frame 2. It is provided detachably so as to close an open end (left end in FIG. 1) when it is arranged up and down, and has a V-shaped notch 3a at the center and is formed to have substantially the same thickness as the frame 2. The roller holder 3 and the upper and lower parallel sides of the U-shaped frame 2 are respectively provided with the guide rollers 4 in contact with the upper and lower parallel sides so as to be movable in the horizontal direction between both sides.
And a trolley 5 formed with substantially the same thickness as the frame 2
And a hydraulic cylinder 6 fixed horizontally to a side that connects two parallel sides vertically and provided horizontally. The roller holder 3 has a pair of backup rollers 7,7.
Are arranged opposite to each other at a predetermined interval with a V-shaped notch 3a therebetween, and the roller holder 3 is fixed to the frame 2 by pins 3b, 3b. The trolley 5 has a vanish roller 8 rotatably provided at the center of its tip (the left end in FIG. 1). And backup roller 7,
The length of the three rollers 7 and the burnishing roller 8 is formed to a length corresponding to the width of the journal portion J or the pin portion P of the crankshaft W to be burnished, and the diameter of the burnishing roller 8 is The diameter of the two backup rollers 7, 7 is formed larger than that of the varnish roller 8 in order to reduce the surface pressure, in order to increase the surface pressure when pressed against the processing surface. .

The trolley 5 is connected to a tip of a piston rod 6 a of a hydraulic cylinder 6 via a load cell 9. Further, a displacement detector 10 is provided in the hydraulic cylinder 6, and the piston rod 6a is driven forward and backward by hydraulic pressure.
Can be detected. The hydraulic cylinder 6 is provided with a servo valve 11, and a hydraulic hose 12 is connected to the servo valve 11.

The control unit 1b includes a control device 13, a program unit 14, and a hydraulic power source 15. The control device 13 includes a pressing force of the vanish roller 8 detected by the load cell 9 and a displacement detector.
Data such as the movement amount of the trolley 5 detected by 10 and the rotation angle of the crankshaft W detected by the rotary encoder 13a (see FIG. 3) are input, and based on these input data. The control signal is output to the servo valve 11 of the hydraulic cylinder 6. The program unit 14 is connected to the control device 13, and the hydraulic source 15 is connected to the other end of the hydraulic hose 12 connected to the servo valve 11.

Further, on the processing portion 1a of the roller burnishing machine 1 configured as described above, slide rails 16, which are provided one by one on the base end side (the right side in FIG. 16 and floating bracket 17
The floating bracket 17 is rotatably supported by a pin 18, and the lower part of the floating bracket 17 is rotatably supported by a pin 18.Furthermore, the spring 19 is stretched between the base 20 and the floating bracket 17 so as to be horizontal in a normal state. The processing portion 1a is configured so that swinging in the vertical direction with the pin 18 as a fulcrum and sliding in the horizontal direction in FIG. 2 are simultaneously allowed.

On the other hand, the crankshaft W processed by the roller burnishing machine 1 is set on the machine stand 21 such that the center line L of the journal J serving as the center of rotation is horizontal as shown in FIG. A pair of spindles 22 and 23 are arranged on both sides of the processing machine base 21 so as to face each other. Chuck devices 24 and 25 are attached to the spindles 22 and 23, respectively. Are centered and supported by respective centers 24a, 25a of both chuck devices 24, 25. A servo motor 26 whose start / stop is precisely controlled by a rotary encoder 26a is provided outside one of the spindles 22 to decelerate the spindle 22. Also, this spindle 22
The chuck device 24 attached to the is provided with a Keray part 27 so as to rotate integrally with the chuck device 24,
By fixing the kelly portion embedding 27 to the crankshaft W, the torque of the spindle 22 can be reliably transmitted to the crankshaft W supported between the centers 24a and 25a of the chuck devices 24 and 25. ing.

The Fig. 4, the crankshaft W ₁ both centers 24a for 6-cylinder engine, but showing a support state between 25a, the journal portion J ₁ through J ₇ of the crankshaft W ₁ As seen from this figure, and the pin portion P ₁ to P ₆ are in a determined position, respectively, the oil hole H for lubricating oil supply is formed. In particular, when the crankshaft W ₁ for the six-cylinder engine, the pin portion P ₁ to P ₆
Are formed with a phase shift of 120 degrees each, so that the formation positions of the oil holes H are various.

Therefore, the journal portion J ₁ through J ₇ and the pin portion P ₁ to P ₆
In order to accurately indexable positions of each oil hole H as the specific locations are formed on, it is necessary to fix the crankshaft W ₁ and accurately positioned on the chuck device 24, 25 as shown in Figure 4 in the case of this example, are based on the key groove K of the crank pulley mounting on the front side of the crank shaft W _1, i.e. timing gears mounted side (left end in FIG. 4). In addition,
The position of the key groove K is determined based on the same part as the position where each oil hole H is formed. Therefore, the chuck device
As shown in FIG. 5, the positioning performed by using the torque transmitting kelle portion 27 provided integrally with the
With positioning by fitting the positioning pins 28 into the key groove K of the crank pulley mounting portion of the inserted crankshaft W ₁ to 27, brought into engagement respectively with three cam claws 29 on the outer periphery of the crank pulley mounting portion friend The rotation of the spindle 22 is restricted so that the rotation is reliably transmitted to the crankshaft W.

The program 14 of the control unit 1b of the roller burnishing machine 1 includes each journal J and each pin P of the crankshaft W on which the burnishing is performed by the machine 1.
A load pattern control program for reducing the pressing force of the vanish roller 8 to a predetermined thickness at each position of the oil hole H based on the data of the rotational direction position of the oil hole H formed at each position is installed. Have been.

Next, the operation of this embodiment configured as described above will be described.

As shown in FIG. 3, the crankshaft W has both ends supported by the centers 24a and 25a of the chuck devices 24 and 25, and the crank pulley mounting portion on the front side has a kelly portion 27 on one chuck device 24 side. In order to determine the position of the oil hole H, the positioning pin 28 is fitted into the key groove K for positioning. It is set horizontally on the processing machine base 21.

Next, the processing portion 1a of the roller burnishing machine 1 is fixed to a predetermined position on the working machine base 21. At this time, the flat frame 2 is perpendicular to the center line L of the crankshaft W, that is, the moving direction of the trolley 5 to which the vanish roller 8 is attached is
And the roller holder 3 fixed with the pins 3b, 3b is removed, and the rod 6a of the hydraulic cylinder 6 is retracted to retract the trolley 5.

The journal portion J or the pin portion P of the crankshaft W to be subjected to the burnishing is positioned inside the U-shaped frame 2, and the center line of the processed portion 1a is arranged to be perpendicular to the processed surface. Thereafter, the processing portion 1a is fixed to the processing machine base 21 by bolting the base 20 and finally the roller holder 3 is mounted, so that the journal portion J or the pin portion P of the crank shaft W is 8 and a pair of backup rollers 7, 7 (see FIG. 2). Then, the processing unit 1a of the roller burnishing machine 1
As shown in FIG. 3, the base 20 is bolted onto the processing machine base 21 (see FIG. 3).

After the processing portion 1a is fixed at a predetermined position, when the servo motor 26 is started next, the rotation of the spindle 22 that is driven at a reduced speed is transmitted to the crankshaft W by transmitting the torque by the kelley portion 27, and the rotation amount is determined by the spindle. When data of the detected rotation amount of the crankshaft W is input to the control device 13 and detected by the rotary encoder 13a provided in the motor 22, machining is performed according to a preset load pattern program. That is, data indicating the position of the programmed oil hole H in the rotational direction and the rotary encoder 13
According to the rotation amount of the crankshaft W detected by a,
The approach to the oil hole H in the journal portion J or the pin portion P of the vanish roller 8 is detected, and based on the detection result, the control device 13 is provided to the servo valve 11 of the hydraulic cylinder 6.
And the servo valve 11 is opened to discharge the pressurized oil in the cylinder, reduce the pressing force of the hydraulic cylinder 6 on the burnishing roller 8 to continue the burnishing, and reduce the pressing force by a predetermined amount. Is detected from the load cell 9, a signal is sent to the servo valve 11 to close the valve. When the crankshaft W further rotates and the contact position of the burnishing roller 8 passes through the oil hole H, the hydraulic pressure in the cylinder is reduced. Rises again to burnish the surface of the journal J or the pin P.

Although the crankshaft W rotates around the center line L, there is no fluctuation. However, when performing the burnishing of the pin portion P that rotates with a locus of a fixed radius around the center line L, the machining is performed. Since the portion 1a is slidably mounted on the floating bracket 17 provided so as to be able to swing vertically with the pin 18 as a fulcrum, the portion between the vanish roller 8 and the backup rollers 7, 7 of the processing portion 1a is The pin portion P pinched between the two is automatically swung and slid in accordance with the rotation of the pin portion P around a rotation center line L along a locus of a constant radius, so that the journal portion J can be burnished. It can be processed in the same way as when.

Thus, the roller burnishing machine 1 of this embodiment
According to this, the outer peripheral surfaces of the journal portion J and the pin portion P of the crankshaft W can be burnished with high precision,
When the contact position of the vanish roller 8 approaches the oil hole H,
Since the pressing force of the vanish roller 8 is controlled to drop by a predetermined amount, the surface pressure of the vanish roller increases in the oil hole portion as in the case of processing with a conventional roller burnishing machine in which the processing load is constant. Therefore, the roundness of the journal J or the pin P is not deteriorated.

Therefore, the roller burnishing machine 1 of this embodiment
The journal portion J and the pin portion P of the crankshaft W finished by the process described above do not cause depression around the oil hole H,
High roundness can be ensured (see FIG. 6).

In this embodiment, the load pattern is programmed in advance in accordance with the position of each oil hole H of each journal J and each pin P, and the rotation amount of the crankshaft W is detected by the rotary encoder 13a. And oil hole H
Has been described in which the processing load is lowered when approaching.
May be changed in proportion to the contact length between the workpiece and the work surface.

Also, by changing the load pattern to be set, for example, when processing a component that undergoes thermal deformation in use such as a cylinder bore, the present invention can be applied to a case where a non-circular shape is formed in consideration of the amount of thermal deformation in advance. Further, by changing the structure of the processing portion 1a, it is possible to provide an apparatus for performing burnishing on the inner peripheral surface of a cylindrical work.

Effect of the Invention As described above, the roller burnishing machine of the present invention includes a burnishing roller that rolls by pressing against a work surface of a work, and a backup that receives a reaction force of the pressing force of the burnishing roller via the work. Rollers, means for pressing the burnishing roller against the work surface of the work, and pressing force control means for reducing the pressing force of the burnishing roller when the burnish roller approaches a specific location on the work surface. Even when the surface of a perforated shaft is burnished, the surface roughness can be significantly improved without deteriorating the roundness of the work by adjusting the pressing force of the burnishing roller according to the amount of rotation of the work can do.

[Brief description of the drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is a view showing the overall configuration of a roller burnishing machine, FIG. 2 is a side view showing a floating mechanism of a working section, and FIG. FIG. 3 is a front view showing a state in which a processing unit is attached to a processing machine base on which a crankshaft is set, FIG. 4 is a partially cutaway sectional view showing a setting state of a crankshaft for a six-cylinder engine, and FIG. FIG. 4 is a sectional view taken along the line VV of FIG. 4, and FIG. 6 is a view showing the roundness of a workpiece when processed by the apparatus of this embodiment.
FIG. 7 is a diagram showing the roundness of a workpiece when processed by a conventional apparatus. DESCRIPTION OF SYMBOLS 1 ... Roller burnishing machine, 1a ... Processing part, 1b ... Control part, 2 ... Frame, 3 ... Roller holder, 5 ... Trolley,
6 hydraulic cylinder, 7 backup roller, 8 vanish roller, 10 displacement detector, 11 servo valve, 12 hydraulic hose, 13 control device, 13a rotary encoder, 1
4 ... Program section, 15 ... Hydraulic source, 16 ... Slide rail, 1
7… Floating bracket, 18… Pin, 20… Base, 2
1 ... Processing machine base, 22,23 ... Spindle, 24,25 ... Chuck device, 26 ... Servo motor, 27 ... Kelley part, 28 ... Positioning pin, 29 ... Cam claw, W, W ₁ ... Crank shaft, J, J _{1 to} J ₇ : journal part, P, P _{1 to} P ₆ : pin part, H: oil hole.

Claims (1)

(57) [Claims] 1. A roller burnishing machine for pressing a roller against a surface to be processed of a rotating workpiece to smoothly process the surface to be processed. A backup roller that receives the reaction force of the pressing force of the roller through the work, a unit that presses the burnishing roller against the work surface of the work, and a burnishing roller when the burnish roller approaches a specific location on the work surface. A roller burnishing machine, comprising: pressing force control means for reducing pressing force.