JPS6250699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device for transporting workpieces in machine tools or industrial machines, in which a transfer bar or a sliding body is started without impact using constant speed rotation by an electric motor, and is continuously accelerated or The present invention relates to an inconstant speed crank motion device that is characterized by slowing down and stopping quietly.

Conventionally, various mechanisms have been considered and used to convert constant speed rotational motion obtained by electric motors etc. into reciprocating motion, but when using a constant speed motion mechanism when transporting a workpiece in a machine tool etc. However, there is a problem in that a rapid change in acceleration occurs when starting or stopping, causing vibration or shock to the workpiece, and as the speed of the device itself increases, an inconstant motion mechanism is required. One example is a system in which the rotational motion of the pinion is directly converted into an acceleration/deceleration feed motion by cranking the pinion, but the cranking motion of the pinion causes changes in the oscillation of the engaged feed rod. There are disadvantages that the device is too large and stable operation cannot be obtained.

Further, even those that utilize a direct piston crank movement mechanism require a larger structure to obtain the required stroke, and have drawbacks in high-speed performance.

In order to deal with the above, patent applications filed by the same applicant as the present invention (Japanese Patent Application No. 55-35961,
No. 134662) has already been proposed, and has provided a device that can smoothly start and stop a moving member by a combination of a crank mechanism that performs inconstant motion and a planetary gear mechanism. By making further improvements to the proposal, we have attempted to realize an inconstant speed crank motion device with even higher high-speed performance. Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional front view, and FIG. 2 is a view taken in the direction of the arrows in FIG. In FIGS. 1 and 2, reference numeral 1 denotes a drive gear, which is fixed to a drive shaft 2. In FIGS. The drive shaft 2 is connected to a reduction gear with a brake motor (not shown), etc., and rotates the drive gear 1. Reference numeral 3 denotes a driven gear, which meshes with the drive gear 1 and rotates as a result. A moving member 4 (transfer bar) having a rack 4a is engaged with the upper part of the driven gear 3, and the moving member 4 is supported so as to be movable in the horizontal direction.

A member 5 such as a crank pin is fitted at a position with a radius r parallel to the axis of the drive shaft 2, and an engaging member 6 is attached to this member. Further, a sliding body 8 is attached to the shaft 7 of the driven gear 3. Reference numeral 9 is a base on which the drive shaft 2 is fitted, and reference numeral 10 is a holding member that swings while keeping the positions of the drive gear 1 and the driven gear 3 constant.

11 is a swing arm with long grooves 11a and 11b.
has been deleted. An engaging member 6 is slidably engaged with the long groove 11a, and a shaft body 8' located at the rotation center of the driven gear 3 is slidably engaged with the long groove 11b. Further, a pin 13 is fitted into one upper end of the swinging arm 11 and one upper end of the support member 12 extending from the base 9.
It is pivoted as a swinging fulcrum. A bracket 14 is attached to the other end of the shaft 7, and a pair of back up rollers 15, 15 are provided above the bracket 14 to support the moving member 4. A connecting rod 17 is extended from one end of the moving member 4 via a pin 16, and a moving base is attached to the other end of the connecting rod 17.

With the above configuration, the drive gear 1 is rotated once at a constant speed by the action of the engagement member 6 provided at a position eccentric to the rotation center of the drive gear 1 and the swing arm 11 that engages with the engagement member 6. As a result, the moving member 4 performs one stroke of inconstant linear motion. The mode of operation will be explained below. FIG. 3 is an operational mode diagram showing the movement of the swing arm 11, and FIG. 4 is an explanatory diagram illustrating the operation of the present device. It is assumed that the shaft 7 of the driven gear starts from O ₂ on the central axis gg. Here, the swing arm 11 is in an upright state with respect to the pin 13. drive gear 1 as ω ₁
When the moving member 4 is rotated in the direction of the _arrow at a constant angular velocity of
When the rotation angle θ=π of the engaging member 6 is reached, the speed v of the moving member becomes v=v _nax . However, after passing θ=π, the moving member 4 is gradually decelerated to θ=2π.
(1 rotation) to stop smoothly. When the movable member 4 is moved backward, the drive gear 1 is reversely rotated (one rotation), and the moving member 4 returns to its original position by following the reverse course of moving forward.

The swing arm 11 starts swinging around point 0 as the rotation angle θ progresses. Here, the swing angle between the center axis gg and the center line of the swing arm 11 is assumed to be. The rotation of the driving gear 1 at a constant angular velocity ω ₁ tends to constantly move the moving member 4 forward in the direction of the arrow through the driven gear 3 at a constant velocity v'. Swinging arm 11 simultaneously moved by engagement member 6
starts swinging in the direction opposite to the forward direction of the moving member 4. Further, since the shaft 7 of the driven gear 3 is slidably fitted into the long groove 11b above the swing arm 11 via the sliding body 8, 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 O ₂ of the shaft 7 of the driven gear 3 due to the swinging motion of the swinging arm 11 and the relative speed due to the planetary rotation of the driven gear 3 reduces the forward speed of the moving member 4. Work in the direction. Therefore, the moving speed v of the moving member ₄ is the composite speed of the moving speed v' of the moving member 4 generated by the constant angular velocity ω1 and the relative moving speed _v3 generated by the swinging of the swinging arm 11. . Since the swing direction of the swing arm 11 changes, it also has the effect of increasing the speed of the moving member 4. That is, in the rotation angle θ=0 to π/2, the vehicle starts smoothly from v=0 and gradually accelerates.

Note that between θ=π/2 and π, the swing direction of the swing arm 11 changes to the same direction as the forward direction and the speed increases, and when θ=π, the speed of the moving member 4 becomes maximum. Next, between θ=π and 3/2π, the speed is gradually decelerated in a state opposite to the speed increase, and between θ=3/2π and 2π, the swinging direction of the swinging arm 11 changes to the opposite direction to the forward direction. The speed of the moving member 4 is further reduced, and the driving gear 1 rotates once and stops smoothly when θ=2π.

As described above, by the swinging action of the swinging arm 11, the horizontal movement speed v of the moving member 4 is made into an inhomogeneous motion, and an ideal transfer speed change can be obtained.

A theoretical analysis of the above operation is as follows.

(1) When calculating the eccentricity of the engaging member for zero start, that is, if the eccentricity of the eccentric engaging member 6 provided on the driven gear 3 is r, the swinging angle of the swinging arm 11 is = tan ^-1 (λsinθ/1−λcosθ)…(
1) However, λ=r/a The angular velocity ω ₁₁ of the swinging arm 11 is ω ₁₁ = λ (cos θ-λ)/1-2λ cos θ+
λ ² ω ₁ ...(2) The moving speed v ₃ of the driven gear 3 is v ₃ = ω ₁₁・R=λ(cosθ−λ)/1−2λcosθ
+λ ²・ω ₁ R…(3) The condition for zero start of the moving member 4 is v′−2v ₃ =0 D ₁ ω ₁ /2−2λ(cosθ−λ)ω ₁ /1−2λc
osθ+λ ²・R=0…(4) As θ=0 However, D ₁ is the pitch diameter of drive gear 1. Therefore, (2) When calculating the speed of the moving member The composite speed V of the moving member 4 is V = v _H + v ₂ ... (6) where v _H is the horizontal component speed of the center movement speed of the driven gear 3 Relative circumference of the driven gear 3 The speed v ₂ and the angular velocity ω ₁₀ of the holding member 10 are α=sin ^-1 (a/b sin) - = sin ^-1 (a/b sin ω ₁₁ t) - ω ₁₁ t...(7) The rotation speed N ₁₀ of the holding member 10 is N ₁₀ = 30ω ₁₀ /π (rev/min) (9) The relative rotation speed N ₃ of the driven gear 3 is N ₃ = (1+Z ₁ /Z ₂ )N ₁₀ −Z ₁ /Z ₂ N ₁ …(10
) However, Z ₁ and Z ₂ are the number of teeth of gears 1 and 3 Relative circumferential speed v ₂ = π・D ₂・N ₃ However, D ₂ is the pitch diameter of driven gear 3 Therefore, (3) When calculating the displacement of a moving member The displacement S of a moving member is S=π/180・D ₁ /2(θ−α)−b(sinα−π
/180・D ₂ /2・α) = π/180(D ₁ /2・θ−b・α)−b sinα
...(12) By applying the actual values to each of the above equations, the radii r, v, and s can be determined. FIG. 5A is an embodiment of the operating characteristic diagram of inconstant speed crank motion according to the present invention. As shown in the v-θ diagram in FIG. It is clear that it stops smoothly without any friction.
Figure B shows the relationship between the horizontal displacement S of the moving member 4 and θ.

Further, FIG. 5B shows a curve of the acceleration a' of the moving member 4 and the time t. A and B are diagrams showing cycloidal curve motion, and in the case of B, the maximum value of velocity acceleration is larger than that of uniformly accelerated single chord motion, so it is suitable for high speeds and light loads. On the other hand, diagram A according to the present invention has a shape in which a constant velocity part is inserted into the maximum speed part of the cycloidal curve motion, and both velocity and acceleration are lower overall than the cycloidal curve motion, and the maximum acceleration is lower than that of the cycloidal curve motion. Since the position is also outside the cycloid curve movement, a speed curve suitable for conveying heavy objects can be obtained.

According to the present invention, the structure of the entire transfer device is compact and simple, which has the advantage of requiring less space and being able to be manufactured at low cost. Furthermore, since the swinging change of the moving member 4 is small, it can be ignored. Since the speed change when the moving member 4 starts and stops is small and operations can be performed smoothly, there is also the advantage that the positioning accuracy of the moving table can be improved, and it can be applied to various mechanical transfer devices.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention.
The figure is a vertical cross-sectional front view, FIG. 2 is a view taken in the direction of the arrow in FIG. 1, FIG. 3 is an operation mode diagram showing the movement of the swing arm, and FIG.
Figures 5A and 5B show operating characteristic curves. DESCRIPTION OF SYMBOLS 1... Drive gear, 2... Drive shaft, 3... Driven gear, 4... Moving member, 6... Engaging member, 8... Slide body, 7... Shaft, 8'... Shaft body, 9 ... Base, 10 ... Holding member, 11 ... Swing arm, 1
1a, 11b...Long groove, 12...Supporting member, 13
... Pin, 14 ... Bracket, 15 ... Backup roller, 16 ... Pin, 17 ... Connecting rod.

Claims (1)

[Claims] 1 a base 9, a drive shaft 2 rotatably provided on the base 9, a drive gear 1 connected to the drive shaft 2,
an engaging member 6 provided eccentrically with respect to the rotation center of the driving gear 1; a driven gear 3 that meshes with and follows the driving gear 1; and a holding member 10 for holding the positions of the driving gear 1 and the driven gear 3; A swinging arm 11 in which the engaging member 6 and a shaft 8' located at the center of rotation of the driven gear 3 are slidably engaged and held, and a moving member that is transmitted and driven by the driven gear 3 and moves in a linear direction. 4, a support member 12 extending from the base 9 to above the movable member 4, and a swing arm 11 pivoted to the upper end of the support member 12 with the upper end of the swing arm 11 as a swing fulcrum. An inconstant velocity crank motion device characterized by: