JPH0525604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for correcting a crankshaft mirror in which a rank shaft is machined.

Prior Art Conventionally, a crankshaft mirror for cutting the crankshaft of an internal combustion engine cuts a cutter centered at the center O of the workpiece by combining a swinging motion (θ) and a linear motion (S), as shown in Fig. 1. The circular motion of the center Q is obtained, and in order to correct the roundness of the workpiece,
When it is desired to change the radius r of the locus of the cutter center Q by a minute amount Δr, the amounts of change Δθ and ΔS of θ and S need to be determined by the following equations.

θ=sin ^-1 {Ecosα+r・cos(α−φ)/l} S=l(cosθ−1)−Esinα−r・sin(α−φ) Note that α is the angle of the machining start point, and φ is the machining start point. The amount of movement from the point, r is the radius of the trajectory of the cutter center Q,
E is the distance when making a 1/2 stroke, l is the swing radius, and Δθ and ΔS are the changes in angle and amount of movement when the cutter center Q moves minutely on the trajectory.

However, the calculation using the above formula is very complicated and must be calculated for each point Q ₁ , Q ₂ . Because it was stopped, there were problems such as poor productivity.

Purpose of the Invention The present invention was made with the aim of improving the above-mentioned problems, and is a crankshaft mirror in which the calculation formula is simplified by approximately determining the amount of change Δθ and ΔS in θ and S when changing the deformation Δr. The purpose of this paper is to provide a correction method to reduce calculation time and improve work efficiency.

Structure of the Invention In order to achieve the above object, the present invention provides a crank mechanism in which a slide that is linearly moved by a slide drive source is provided with a swingable disk, and this disk is provided with a cutter that cuts a workpiece while rotating in one direction. When changing the radius r of the locus of the rotation center Q of the cutter by a minute amount in order to correct the roundness of the machined workpiece in a shaft mirror, θ' and S' are approximately determined using the following equations. , obtained θ′,
The swing angle of the disk and the amount of movement of the slide are corrected based on S'.

θ′=θ+Δrcosφ/l・π/180・cosθ S′=S+Δr・(−tanθ・cosφ+sinφ) where θ: Swing angle at angle φ when radius r s: Linear movement at angle φ when radius r Quantity l: Swing radius In addition, by employing the above correction method, the minute changes Δθ and ΔS of the swing angle θ and the movement amount S can be calculated in a short time, so the amount of time the machine is stopped is This will shorten the time and improve productivity.

Embodiment An embodiment of the method of the present invention will be described in detail with reference to the drawings shown in FIG. A slide 4 is housed within the saddle 2 and is capable of reciprocating in a direction perpendicular to the bed 1 by a slide drive source 3. Slide 4 above
A disk 5 is accommodated therein so as to be able to swing freely in the direction of the arrow around the disk center Cd, and a circular hole 5a is opened at an eccentric position of the disk 5. A rotating annular cutter drum 6 is housed therein. The cutter drum 6 has a large number of cutters 6a protruding from its inner peripheral surface, and the center Cc of the cutter 6a is adjusted by the linear movement (S) of the slide 4, the swinging movement (θ) of the disk 5, and the rotation of the cutter drum 6. The cutter 6a rotates around the center Cp of the workpiece 7 as shown in FIGS. 3a to 3e to cut the outer circumferential surface of the workpiece 7.

Next, the operation will be explained. At the same time as the slide 4 is reciprocated in the linear direction, the disk 5 provided on the slide 4 is swung around the swing center P shown in FIG. Katsuta 6
While a is being rotated counterclockwise, the workpiece 7
This involves cutting the outer peripheral surface of the
Shown in figures a to e.

Furthermore, when the roundness of the machined part of the workpiece 7 machined as described above was measured using a circularity measuring device, it was found that errors δ ₀ , δ ₁ , etc. as shown in FIG. 5 had occurred. To correct the error, cutter center Q
It is necessary to change the radius r of the trajectory by a minute amount Δr.

Conventionally, as mentioned above, the correction amount was calculated by calculating Δθ and ΔS using a complicated calculation formula, but in this invention, Δθ and ΔS are calculated by the following formula when r is changed by a minute amount Δr. did.

That is, considering Δθ and ΔS when the radius r of the locus of the cutter center Q changes by Δr as shown in FIG. 4, the following relationship exists between Δr, Δθ, and ΔS.

l sin(θ+Δθ)=Δrcosφ+lsinθ l cos(θ+Δθ)=ΔS−Δrsinφ+lcosθ In the above formula, when Δr≒0, if Δθ≒0 sin(θ+Δθ)≒sinθ+Δθ×π／180×cosθ cos(θ+Δθ)≒cosθ+Δθ×π／180×sinθ Since the relationship holds true, Δθ=Δrcosφ/l・π/180cosθ ΔS=Δr(−tanθ・cosφ+sinφ) becomes.

Therefore, from the approximate values θ′=θ+Δθ, S′=S+ΔS, θ,
Since the value of S can be easily determined, the calculation formula can be simplified and the calculation time can be shortened.

Effects of the Invention As described in detail above, the present invention provides a crankshaft mirror in which a work piece is excavated by making a cutter oscillate by a disk and move linearly by a slide, by changing the radius r of the locus of the rotation center Q of the cutter by a minute amount. When changing Δr, the calculation formula is simplified by approximately determining the amount of change Δθ and ΔS in θ and S when Δr changes, so the calculation time can be significantly reduced compared to the conventional calculation formula.

As a result, even if an error occurs in the roundness of the machined workpiece, it is possible to calculate the correction amount and correct the roundness in a short time, and the machine stop time is reduced compared to conventional methods. This also improves productivity.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a device that makes a certain point circularly move by controlling rocking motion and linear motion, Fig. 2 is a schematic configuration diagram of a crankshaft mirror embodying the present invention, and Figs. 3 a to e and FIG. 4 is an explanatory diagram of the same effect, and FIG. 5 is an explanatory diagram showing the roundness measurement results of a workpiece that has been processed.

Claims (1)

[Scope of Claims] 1. A crankshaft in which a slide 4 that is linearly moved by a slide drive source 3 is provided with a swingable disk 5, and a cutter 6a that cuts a workpiece 7 while rotating in one direction is provided on the disk 5. In the mirror, when the radius r of the locus of the rotation center Q of the cutter 6a is changed by a minute amount Δr in order to correct the roundness of the machined workpiece 7, θ', S' can be approximated by the following equations. A method for correcting a crankshaft mirror, characterized in that the swing angle of the disk 5 and the amount of movement of the slide 4 are corrected based on the obtained θ' and S'. θ′=θ+Δrcosφ/l・π/180・cosθ S′=S+Δr・(−tanθ・cosφ+sinφ) where θ: Swing angle at angle φ when radius is r s: Linear movement amount at angle φ when radius is r l: Swing radius