JP4846920B2 - Oscillation type grinding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oscillation type grinding apparatus.
[0002]
[Prior art]
For example, according to Japanese Patent Laid-Open No. 61-25765 “Crankshaft finishing device”, according to FIG. The workpiece receiver 3, the slide table 4, the gantry 5, and the machining head 6 are arranged, and the shaft portion Wa of the crankshaft W supported by the oscillation device 2 and the workpiece receiver 3 is ground with a grindstone provided on the machining head 6. It is a device.
[0003]
FIG. 4 is a detailed view of the machining head 6. The machining head 6 has a swinging fulcrum 5a fitted in a long hole (reference numeral 6e of reference numeral 6 is correct) opened in the rear part (right end in the figure) of the arm 6b. By combining, it can be moved to the left and right of the drawing, and can be swung up and down. The arm 6 is provided with a substantially C-shaped workpiece insertion portion 6a at the tip (left end in the figure), and the shaft Wa inserted into the workpiece insertion portion 6a is finished with the finishing grindstones 7, 7, 7. The shaft portion Wa is rotated as shown by the arrow, and the shaft portion Wa is evenly finished while reciprocating in the front and back direction of FIG. 4 by the action of the oscillation device 2 of FIG.
[0004]
If the shaft portion Wa is the pin portion of the crankshaft, the shaft portion Wa revolves while rotating, so that the arm 6b moves up, down, left and right in the drawing. At that time, the tip of the arm 6b is pulled up by the balancer spring 6d so that no load is applied to the shaft portion 6a.
[0005]
FIGS. 4A to 4C are principle diagrams of a conventional crankshaft finishing apparatus.
(A), a grindstone 103 is provided at the tip of an arm 102 supported by a swing support shaft 101 so as to be swingable in the direction of the front and back of the drawing. At this time, the pin portion 105 is finished with the grindstone 103 by rotating the crankshaft 104 according to the arrow while oscillating the crankshaft 104 to the left and right as indicated by the white arrow.
[0006]
Specifically, as shown in (b), the pin portion 105 is moved to the right, and then, as shown in (c), the pin portion 105 is moved to the left to finish the pin portion 105. This is the operating principle of the device.
[0007]
[Problems to be solved by the invention]
By the way, when an attempt was made to increase the oscillation speed by about 2 times due to the demand for improvement in productivity, it was found that the finishing accuracy of the pin portion 105 was lowered. In order to analyze this factor, the following measurements were performed.
FIG. 5 is a principle diagram of vibration measurement. One of the three grindstones 103 attached to the tip of the arm (... indicates a plurality, the same applies hereinafter) is used for cause analysis. An eddy current pickup 111 was attached, a signal detected by the eddy current pickup 111 was amplified by an amplifier 112, and the vibration phenomenon of the grindstone 103 was measured by a display 113 having a waveform diagram generation function.
[0008]
FIG. 6A is a movement waveform diagram of a workpiece and a grindstone in a conventional crankshaft finishing apparatus, and FIG. 6B is a graph showing a relative movement amount.
In (a), the horizontal axis indicates time, the vertical axis indicates the amount of movement of the workpiece (crankshaft) or the grindstone, and the right and left indicate the movement direction. Since the work is reciprocated at a predetermined cycle time by a fixed oscillation amount by the oscillation device, a sine curve waveform as shown in the figure is drawn. On the other hand, it was found that the whetstone draws a sine curve waveform delayed by Δt1. If you look at the waveform of this grinding wheel in detail, the cycle time is the same as that of the workpiece, but the height of the mountain is small. From this, it was found that the whetstone that should have been stationary is moving in a "moving" manner with the workpiece.
[0009]
A line parallel to the vertical axis is drawn at t1 on the time axis of (a), and a difference δ in the amount of movement between the workpiece curve and the grindstone curve along this line is obtained. A curve obtained by obtaining a number of δ by this procedure and collecting them is (b), and the vertical axis of (b) corresponds to the relative movement amount. If the grindstone is in a stationary state, this relative movement amount is equal to the workpiece curve shown in (a), and the maximum value is sufficiently large. However, the maximum value of the relative movement amount shown in (b) is small, and this is a cause of finishing defects.
[0010]
As is clear from FIG. 4A described above, the arm 102 is a cantilever beam supported by the swing support shaft 101, so that the tip easily swings, and the oscillation speed is doubled with this structure. This is the cause of the failure. In view of this, it has been considered to increase the bending rigidity of the arm 102. In the finishing device for the crankshaft, in order to correspond to the multi-cylinder crankshaft, a plurality of arms 102 are arranged closely like comb teeth. Increasing the width W is structurally difficult.
[0011]
[Means for Solving the Problems]
The present inventors are examining measures to replace the measures for increasing the rigidity of the arm. In FIG. 6A, as a matter of course, if the height of the grindstone curve is reduced (that is, the amount of movement of the grindstone is reduced). The shadowed portion increases, and the relative movement amount of (b) increases.
And in order to reduce the movement amount of the grindstone without increasing the rigidity of the arm, increase the inertia in the vicinity of the grindstone to weaken the followability to the workpiece, that is, increase the inertia of the grindstone to slow down the movement of the grindstone. came up with. Therefore, when a mass member was attached to the tip of the arm and an experiment was conducted, the height of the grindstone curve was reduced, and the structure of the present invention was established.
[0012]
That is, according to the first aspect, a substantially C-shaped recess is provided at the tip of a horizontally extending cantilever-shaped arm, and a plurality of slide bars are attached to the arm so as to be slidable toward the center of the recess. A grindstone is attached to the tip of the bar, the grindstone can be brought into contact with the shaft-shaped workpiece taken in the recess, and the shaft-shaped workpiece is rotated while reciprocating a certain distance in the axial direction. In the oscillation type grinding machine for grinding, the inertia of the arm increases and the grindstone is delayed with respect to the movement of the workpiece at a position that does not hinder the insertion and removal of the shaft-like workpiece at the tip of the arm and into the C-shaped recess. A mass member whose follow-up is confirmed by vibration measurement is provided.
[0013]
By attaching a mass member, specifically a weight, to the tip of the arm, the inertia of the arm is increased. When the inertia is increased, the grindstone follows the movement of the work with a delay, and the work is reversed before the grindstone that has started to move with a delay is moved too much. Due to the work being reversed, the grindstone is reversed with a delay. That is, if the inertia of the grindstone is increased, the amount of movement of the grindstone can be made much smaller than the amount of movement of the workpiece. If the movement amount of the grindstone is reduced, the workpiece can be effectively ground.
Therefore, according to the first aspect, the oscillation speed can be increased without increasing the rigidity of the arm, and the productivity of the grinding apparatus can be greatly improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a principle diagram of an oscillation type grinding apparatus before taking countermeasures as a base of the present invention. The oscillation type grinding apparatus (1) before taking countermeasures is capable of moving horizontally on an oscillation support shaft 11 and swinging up and down. An arm 12 that can be mounted, a substantially C-shaped recess 13 provided at the tip of the arm 12, a plurality of slide bars 14 that are slidably mounted toward the center of the recess 13, and these slides It comprises a grindstone 15 attached to the tip of the bar 14... And a cylinder 16 along the arm 12. A shaft-shaped workpiece (not shown) is taken into the substantially C-shaped recess 13 and the slide bar 14 is moved forward so that the grindstones 15 are applied to the shaft-shaped workpiece. And it is a grinding device which finishes an axial work by oscillating, ie, reciprocating, in the drawing front and back direction while rotating an axial work.
[0015]
In order to increase the oscillation speed of the shaft-like workpiece, the mass members 18 and 19 are attached to the tip of the arm 12 as a countermeasure. However, the mass members 18 and 19 are positioned while taking care not to block the opening at the tip of the arm 12.
[0016]
FIG. 2 is a principle view of the main part of the oscillation type grinding apparatus according to the present invention. This oscillation type grinding apparatus 10 has a substantially C-shaped recess 13 at the tip of a horizontally extending cantilever arm 12. And a plurality of slide bars 14... Are attached to the arm 12 so as to be slidable toward the center of the recess 13, and a grindstone 15 is attached to the tips of the slide bars 14. In addition, the mass members 18 and 19 are provided at the tip of the arm 12 and at a portion that does not hinder the insertion and removal of the shaft-like workpiece into the C-shaped recess 13.
[0017]
In the oscillation type grinding apparatus 10 shown in FIG. 2, the following ability of the grindstones 15 to the workpiece was measured in the same manner as in FIG.
FIG. 3A is a movement waveform diagram of the workpiece and the grindstone in the oscillation type grinding apparatus of the present invention, FIG. 3B is a graph showing the relative movement amount, and the drawing method of FIG. I will omit it.
[0018]
In (a), the horizontal axis represents time, the vertical axis represents the amount of movement of a workpiece (an axial workpiece such as a crankshaft) or a grindstone, and the right and left represent the movement direction. Since the work is reciprocated at a predetermined cycle time by a fixed oscillation amount by an oscillation device, a sine curve waveform as shown in the figure is drawn. On the other hand, the grindstone draws a sine curve curve delayed by Δt2, but this curve has a small amplitude (amount of movement).
[0019]
The reason is as follows.
The inertia of the arm was increased by attaching a mass member to the tip of the arm. When the inertia is increased, the grindstone follows the movement of the work with a delay, and the work is reversed before the grindstone that has started to move with a delay is moved too much. Due to the work being reversed, the grindstone is reversed with a delay. That is, if the inertia of the grindstone is increased, the amount of movement of the grindstone can be made much smaller than the amount of movement of the workpiece.
[0020]
The relative movement amount shown in (b) is sufficiently large, and the grindstone can be applied to the workpiece with a movement amount close to the predetermined movement amount. As a result, good finishing accuracy can be obtained. That is, compared with FIG. 6B, FIG. 3B was able to significantly increase the relative movement amount.
[0021]
In addition to the crankshaft, the type of the axial workpiece is not particularly limited as long as it is a camshaft, a balancer shaft, or the like.
[0022]
【The invention's effect】
The present invention exhibits the following effects by the above configuration.
According to the first aspect of the present invention, the inertia of the arm is enhanced by attaching a mass member, specifically, a weight to the tip of the arm. When the inertia is increased, the grindstone follows the movement of the work with a delay, and the work is reversed before the grindstone that has started to move with a delay is moved too much. Due to the work being reversed, the grindstone is reversed with a delay. That is, if the inertia of the grindstone is increased, the amount of movement of the grindstone can be made much smaller than the amount of movement of the workpiece. Therefore, grindability can be ensured even if the oscillation speed is increased.
Therefore, according to the first aspect, the oscillation speed can be increased without increasing the rigidity of the arm, and the productivity of the grinding apparatus can be greatly improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing the principle of an oscillation type grinding apparatus before taking measures as a base of the present invention. FIG. 2 is a diagram showing the principle of an essential part of an oscillation type grinding apparatus according to the present invention. Fig. 4 is a graph showing the relative movement of the workpiece and the grindstone in the oscillation type grinding machine. Fig. 4 is a diagram showing the principle of a conventional crankshaft finishing device. Fig. 5 is a diagram showing the principle of vibration measurement. 6 (a) is a movement waveform diagram of a workpiece and a grindstone in a conventional crankshaft finishing device, and (b) is a graph showing a relative movement amount.
DESCRIPTION OF SYMBOLS 1 ... Oscillation type grinding device before countermeasure, 10 ... Oscillation type grinding device of this invention, 11 ... Swing support shaft, 12 ... Arm, 13 ... Substantially C-shaped recessed part, 14 ... Slide bar, 15 ... Grinding wheel, 18, 19 ... Mass members.

Claims (1)

A substantially C-shaped recess is provided at the tip of a horizontally extending cantilever-shaped arm, and a plurality of slide bars are attached to the arm so as to be slidable toward the center of the recess. The grindstone can be brought into contact with the shaft-shaped workpiece taken in the recess, and a predetermined portion of the shaft-shaped workpiece is ground with the grindstone by rotating the shaft-shaped workpiece while reciprocating in the axial direction by a predetermined distance. In the oscillation type grinding machine
Vibration measurement indicates that the inertia of the arm increases and the grindstone follows the movement of the workpiece with a delay at a position that does not prevent the shaft-shaped workpiece from being put into and out of the tip of the arm and into the C-shaped recess. An oscillation type grinding apparatus, wherein a confirmed mass member is attached.

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