JPS6237272B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical feed device such as a transfer device for transporting a workpiece in a machine tool or an industrial machine. The present invention is a non-uniform motion mechanism, and the reason why the non-uniform motion mechanism is adopted in a transfer device, etc. is because as the speed of the transfer device increases, a uniform motion mechanism has a rapid acceleration when starting and stopping. This is because vibrations and shocks are large due to changes. Another advantage is that the time required for the process can be shortened.

The object of the present invention relates to a mechanism that converts constant speed rotational drive into inhomogeneous reciprocating motion. That is, the present invention provides a new type of mechanism in which the moving table starts and stops smoothly and reciprocates by combining a crank mechanism that performs non-uniform motion and a planetary gear mechanism.

Although there have been inventions related to this type of inconstant velocity movement mechanism in the past, there have been various difficulties.

For example, there is a device that converts a pinion into an acceleration/deceleration feed motion by cranking a pinion, but the cranking motion of the pinion causes too large a swing change in the meshing feed rod, making the device too large. However, stable operation could not be obtained.

Furthermore, even those that utilize a direct piston-crank movement mechanism have to be large due to their structure in order to obtain the required stroke.

According to the present invention, the above problems are solved, and a stable device with a simple structure and reliable operation can be obtained. Moreover, it is easy to adjust the feed speed.

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 denotes a drive body (hereinafter referred to as a drive gear), which is fixed to a drive shaft 5. As shown in FIG. For example, a reduction gear with a brake electric motor or the like is connected to the drive shaft 5. The driving gear 1 meshes with a driven body (hereinafter referred to as driven gear 2). A moving member (hereinafter referred to as transfer bar 4) having a rack 4a is meshed with the upper part of the driven gear 2, and the transfer bar 4 is supported so as to be movable in the horizontal direction. A crank pin 6 is fitted in a position parallel to the axis of the drive shaft 5 at a radius γ, and an engaging member (hereinafter referred to as a sliding body 7) is attached. In addition, the shaft 8 of the driven gear 2
A sliding body 9 is similarly attached to the same. A pin 11 is fitted into the base (hereinafter referred to as a fixed stand 10) into which the drive shaft 5 is fitted. The pin 11 pivotably supports a swing arm (hereinafter referred to as crank arm 3). Long grooves 3a and 3b are cut into the crank arm 3. The two sliding bodies 7 and 9 are arranged in the long groove 3.
It is slidably engaged with a and 3b. A holding member (hereinafter referred to as a holding arm 12) is attached to the drive shaft 5 and the shaft 8 to hold the drive gear 1 and the driven gear 2.
It is held and provided to maintain the meshing state of the two. The driven gear 2 rotates planetarily relative to the drive gear 1. A bracket 13 is rotatably fitted into the other end of the shaft 8, and a pair of back-up rollers 14 are provided above the bracket 13 to support the transfer fiber 4. A connecting rod 16 is extended from one end of the transfer bar 4 via a pin 15, and a moving platform is attached to the other end of the connecting rod 16.

With the above configuration, when the drive gear 1 rotates once at a constant speed, the transfer bar 4 rotates once.
Performs inconstant linear motion of the stroke.

Hereinafter, the operation of the inconstant velocity crank motion device of the present invention will be explained. FIG. 3 is a schematic diagram of the present invention. It is assumed that the crank pin 6 starts from _0'1 on the central axis gg. Here, the crank arm 3 is in an upright state with respect to the pin 11 (the position indicated by the two-dot chain line). The drive gear 1
When the transfer bar 4 is rotated in the direction of the arrow at a constant angular velocity of _ω1 , the transfer bar 4 smoothly starts moving in the direction of the arrow from a moving speed υ=0 in the horizontal direction for reasons that will be described later. According to the rotation angle θ of the crank pin 6, the transfer bar 4 is gradually accelerated and increases in speed, and when θ=π is reached, υ=υmax. However, after passing θ=π, the transfer bar 4 is gradually decelerated and smoothly stops at θ=2π (one rotation). When the transfer bar 4 is retracted, the drive gear 1 is reversely rotated (one rotation), and the transfer bar 4 returns to its original position following the reverse course of the forward movement.

The crank arm 3 starts to swing around point 0 as the rotation angle θ progresses. Here, the angle formed by the center axis gg and the center line of the crank arm 3 is defined as the swing angle. The rotation of the driving gear 1 at a constant angular velocity ω ₁ tends to constantly move the transfer bar 4 forward in the direction of the arrow via the driven gear 2 at a constant velocity υ′. At the same time, crank pin 6
The crank arm 3, which is interlocked by this, starts to swing in the direction opposite to the direction in which the transfer bar 4 moves forward. Further, since the shaft 8 of the driven gear 2 is slidably fitted into the long groove 3b above the crank arm 3, it rotates planetarily in the same direction as the rotational direction of the drive gear 1.

The reduction in the moving speed of the center ₀₂ of the driven gear 2 due to the rocking motion of the crank arm 3 and the relative speed due to the planetary rotation of the driven gear 2 acts to reduce the forward speed of the transfer bar 4. Therefore, the moving speed υ' of the transfer bar 4 generated by the constant angular velocity ω ₁ and the crank arm 3
The composite speed of the relative movement speed _υ3 generated by the swinging of the transfer fiber 4 becomes the movement speed υ of the transfer fiber 4. Furthermore, since the direction of swing of the crank arm 4 changes, it also has the effect of increasing speed. In the rotation angle θ=0 to π/2, the vehicle starts smoothly from υ=0 and gradually accelerates. Between θ=π/2 and π, the swinging direction of the crank arm 4 is the same as the forward direction, so the speed gradually increases from near υ′. θ=υ
max, and gradually decelerates to near υ' between θ=π and 3π/2. Between θ=3π/2 and 2π, the speed is further decelerated until it stops smoothly and υ=0.

The above-described nature of the swinging of the crank arm 3 causes the horizontal movement speed υ of the transfer bar 4 to be an inhomogeneous movement, thereby obtaining an ideal transfer speed change.

Further, when the operation of the present invention is theoretically analyzed, it is as follows.

In FIG. 3, the relationship between the swing angle of the crank arm 3 and the rotation angle θ of the crank pin 6 is tan = γ sin θ, where γ is the crank pin radius and l is the distance from the swing center 0 to 0 ₁ . /l+γcosθ = tan ^-1 (λsinθ/1+λcosθ), λ=γ
/l.

The angular velocity ω ₃ of the crank arm 3 is given as follows.

π ₃ = d/dt=d/dθ・dθ/dt=d/dθ・ω ₁ ω ₃ =d{tan ⁻¹ (λsinθ/(1+λcosθ))}/dθ・ω ₁ =λ(λ+cosθ)/1+λ ² +2
λ cos θ·ω ₁ The relative moving speed υ ₃ of the crank arm 3 at the center 0 ₂ is as follows, where L is the distance from the swing center 0 to the center 0 ₂ .

υ ₃ =L・ω ₃ =λ(λ+cosθ)/1+λ ² 2λ
cos θL·ω ₁ When the driven gear 2 does not revolve around the driving gear 1, the moving speed υ′ of the transfer bar 4 at a constant angular velocity ω ₁ is calculated as follows.
Here, the pitch diameter of the drive gear 1 is D ₁ , the rotation speed is N ₁ (rpm), and C is a coefficient.

υ′=π・cD ₁・N ₁ /c = π・D ₁・π ₁ /2π=1/2・D ₁・ω ₁ The moving speed υ of the transfer fiber 4 is υ′ and υ
Since it is a composite speed of ₃ , it can be obtained by the following formula.

υ=υ′−υ ₃ = (1/2D ₁ −λ(λ+cosθ)/1+λ ² +2
λ cos θ・L)・ω ₁ Furthermore, in order for the drive gear 1 to start (or stop) from zero from 0' ₁ on the central axis gg, the following conditions are necessary.

υ'-2υ ₃ = 0 Therefore, 1/2・D ₁・ω ₁ −2・λ(λ+cosθ)/1+λ ² +2λco
sθ・L・ω ₁ =0 (4L−D ₁ )・λ ² +2・(2L−D ₁ )・λ−D ₁ =0 (θ=0) As a specific example, D ₁ =300mm, l=300mm, L=
If it is 600mm, That is, the crank pin radial position γ can be set to 4286 mm.

FIG. 4A is a υ-θ diagram of the inconstant velocity crank motion device according to the present invention. It is clear that the speed υ of the transfer bar 4 is such that it starts smoothly and stops smoothly. FIG. 4B is a diagram showing the relationship between the horizontal displacement x of the transfer bar 4 and the acceleration a with the crankpin rotation angle θ.

FIG. 5 and FIG. 6 are diagrams showing other embodiments. It is also possible to attach a sprocket 17 to the shaft 8 of the driven gear 2 and use the sprocket 17 to move the roller chain 18 in the horizontal direction. The roller chain 18 is connected to a moving table.

Therefore, it can also be applied to a conveying device such as a DNC line, so that objects to be conveyed can be conveyed continuously and intermittently.

According to the present invention, since the structure is compact and simple, the space required is small and there is an advantage that it can be manufactured at low cost. Moreover, since the swinging change of the transbar 4 is small (the δ dimension in FIG. 3), it can be ignored. By the way, the maximum swing change amount δmax of the transfer bar 4 is determined by the numerical values of the above-mentioned specific example.
(θ=π/2, 3π/2), δmax=L−2l/1+tan ² , so δmax=12mm.

In addition, as shown in Figure 4A, compared to conventionally used inconstant speed driving mechanisms in which speed changes have a sinusoidal waveform, speed changes during starting and stopping are small and can be configured smoothly. This has the advantage that the positioning accuracy of the moving table can be improved.

Further, if the positions of the pin 11 and the crank pin 6 are configured to be adjustable using conventional techniques, the speed of the transfer bar 4 can be easily adjusted.

As stated above, the present invention is not limited to the configurations shown in the examples, and modifications are expected within the scope of the technical idea of the present invention as described in the claims. be.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional front view showing an embodiment of the inconstant velocity crank movement mechanism according to the present invention, FIG. 2 is a view taken in the direction of the arrow in FIG. 1, and FIG. 3 is a mechanism diagram schematically showing the present invention. Figure 4 A is a velocity diagram of the transfer lever 4, Figure 4 B is a displacement diagram of the transfer lever 4,
and an acceleration diagram, FIG. 5 is a vertical cross-sectional front view showing another embodiment, and FIG. 6 is a view taken in the direction of the arrow in FIG. In the figure, 1...driving gear, 2...driven gear, 3...
Crank arm, 4...transfer bar,...swing angle, 6...crank pin, θ...crank pin rotation angle, 8...shaft, 10...fixing base, 11...pin,
12...holding arm, 13...bracket.

Claims (1)

[Claims] 1 a base 10, a drive body 1 rotatably provided on the base 10, an engaging member 7 eccentrically provided on the drive body 1 parallel to the rotation axis, and the drive body 1
a driven body 2 that rotates by being transmitted from the driven body 2; a rotatable holding member 12 that maintains the transmission state between the driven body 2 and the driving body 1; and a rotation center axis of the engaging member 7 and the driven body 2. comprises a swinging arm 3 that is slidably engaged with the base 10 and swings using one end of the base 10 as a fulcrum, and a moving member 4 that is transmitted and driven from the driven body 2 and moves in a linear direction. 1
An inconstant speed crank motion device characterized in that the moving member 4 can be moved in a straight line direction continuously at an inconstant speed by rotation of the moving member 4.