CN103398150A - Space crank-rocker mechanism capable of moving intermittently - Google Patents

Abstract

The invention provides a space crank-rocker mechanism capable of moving intermittently. The space crank-rocker mechanism capable of moving intermittently comprises a rocker, a connecting rod, a crank and a rack. The rocker and the rack form a first revolute pair. The crank and the rack form a second revolute pair. The rocker and the connecting rod form a first spherical pair. The connecting rod and the crank form a second spherical pair. The axis of the rocker intersects with the axis of the crank in a perpendicular mode. The axis of the crank passes through a movement plane of the rocker. The crank rotates one circle, and the rocker can swing in a reciprocating mode and then stops. The turn angles of the crank corresponding to the reciprocating swing time and the stop time are approximately the same. The space crank-rocker mechanism capable of moving intermittently is simple in structure, low in manufacturing cost, high in stop accuracy, good in force transmission performance, and capable of being widely applied to the occasions of intermittent feeding, control and the like.

Description

Space crank rocker mechanism capable of intermittently moving

Technical Field

The invention relates to a space crank rocker mechanism capable of intermittently moving, and belongs to the technical field of mechanical transmission.

Background

In some machines (e.g., looms, etc.), the driven member is required to have a relatively long dwell time during movement. At present, a combined mechanism or a multi-rod mechanism, such as a cam-worm gear intermittent mechanism, a cycloid intermittent mechanism, a three-gear drive intermittent mechanism, a six-rod intermittent mechanism and the like, is often required for realizing the function. These mechanisms are complicated in structure, have a large number of components, and often use high-cost auxiliary mechanisms such as cams and gears.

Therefore, there is a need to improve the prior art to overcome the deficiencies of the prior art.

Disclosure of Invention

The invention provides a space crank rocker mechanism which is simple in structure, convenient to manufacture and maintain, good in force transmission performance and high in efficiency and can realize intermittent motion.

The invention adopts the following technical scheme: a space crank rocker mechanism capable of intermittently moving comprises a rocker, a connecting rod, a crank and a rack, wherein the rocker and the rack form a first rotating pair, the crank and the rack form a second rotating pair, the rocker and the connecting rod form a first spherical pair, the connecting rod and the crank form a second spherical pair, the axis of the rocker is vertically intersected with the axis of the crank, the axis of the crank passes through the moving plane of the rocker, and the length relation of each component in the space crank rocker mechanism capable of intermittently moving is as follows:

and is

Wherein,ψ ₀is the maximum swing angle of the rocker arm₁Is the length of the rocker, s is the length of the frame, l₃Is the crank length, /)₂Is the length of the connecting rod, delta>0 and delta<< l₂；

Maximum swing angle of rockerψ ₀Length l of crank₃And the length of the rack s are in the following relation, tg: (ψ ₀/2) = l₃/ s。

The axes of the first rotating pair and the second rotating pair are vertically intersected.

The invention has the following beneficial effects:

(1) the structure is simple, the manufacturing cost is low, the stop precision is high, and the force transmission performance is good;

(2) can be widely applied to occasions of intermittent feeding, control and the like.

Drawings

Fig. 1 is a schematic structural diagram of the spatial crank rocker mechanism capable of intermittently moving according to the invention.

FIG. 2 is a schematic view of the mechanism at the start position

Fig. 3 is a schematic view of the mechanism when the crank is rotated 90 °.

Fig. 4 is a schematic view of the mechanism when the crank is rotated 180 °.

Fig. 5 is a schematic diagram of the mechanism when the crank is rotated through 270 °.

FIG. 6 is a graph of the relationship between the swing angle and the crank angle of the rocker lever according to the present invention.

FIG. 7 is a graph of rocker load torque versus crank drive torque as a function of crank angle for the present invention.

Detailed Description

Referring to fig. 1 to 7, the spatial crank-rocker mechanism capable of intermittent motion of the present invention includes a rocker 1, a connecting rod 2, a crank 3 and a frame 4, wherein the rocker 1 and the frame 4 form a first revolute pair 5, the crank 3 and the frame 4 form a second revolute pair 6, the rocker 1 and the connecting rod 2 form a first spherical pair 7, and the connecting rod 2 and the crank 3 form a second spherical pair 8. Wherein the axes of the first rotating pair 5 and the second rotating pair 6 are vertically intersected. The axis of the rocker 1 is vertically intersected with the axis of the crank 3, the axis of the crank 3 passes through the motion plane of the rocker 1, and the mechanism is a space crank rocker RSSR four-bar mechanism.

To realize the intermittent swing of the rocker, the lengths of the components satisfy the following relationship:

and is

Wherein,ψ ₀is the maximum swing angle of the rocker arm₁Is the length of the rocker, s is the length of the frame, l₃Is the crank length, /)₂Is the length of the connecting rod, delta>0 and delta<< l₂；

Maximum swing angle of rockerψ ₀Length l of crank₃And the length of the rack s are in the following relation, tg: (ψ ₀/2) = l₃/ s。

In a particular embodiment of the invention: wherein the length l of the rocker₁=100mm, link length l₂=149.5mm, crank length l₃=113.738mm, rack lengths=197mm, maximum swing angle of rockerψ ₀=60°，δ=0.0164。

The movement process of the space crank rocker mechanism capable of intermittently moving is as follows:

starting position, i.e. crank angle

Angle of rocking bar 0 DEGψWhen the angle is approximately equal to 0 degrees, the mechanism is shown in the attached figure 2.

The crank rotates from 0 degree to 90 degrees, and the swing angle of the rocker is fromψApproximately equal to 0 degree to reach the maximum swing angle of the rockerψ ₀When is coming into contact with

When the angle is not less than 90 degrees,ψ=ψ ₀the mechanism is shown in figure 3.

The crank rotates from 90 degrees to 180 degrees, and the swing angle of the rocker is from the maximum swing angle of the rockerψ ₀Go back toψ0 DEG when

When the angle is not less than 180 degrees,ψ0 deg. and the mechanism is shown in figure 4.

The crank rotates from 180 degrees to 360 degrees, the rotation angle of the rocker is almost fixed, and the rocker is in an approximate rest state. At this time, the first spherical pair 7 is approximately at the conical top of a cone with the crank axis as the axis, the connecting rod 2 as the generatrix and the motion trail (circle) bottom of the second spherical pair 8, and the mechanism is as shown in fig. 4. When in use

When the angle is not less than 270 degrees,ψ0 deg., the mechanism is as shown in fig. 5.

The crank of the mechanism rotates for a circle, the reciprocating time of the rocker is slightly longer than the rest time, the smaller the delta is, the closer the reciprocating time of the rocker is to the rest time, and the higher the rest precision is. When the limit condition delta =0, the reciprocating time of the rocker is equal to the rest time, the rocker is accurately stopped in the rest time, but the rocker does not have definite movement at one limit position.

Angle of rotation of crank

When the angle is 0-180 degrees, the rocker swings at an angleψOscillating back and forth once in the range of 0 to 60 degrees and rotating by crank angleWhen the angle is 180 degrees to 360 degrees, the rocker swings at an angleψ0 deg., almost motionless. The maximum ratio of the maximum drive torque on crank M3 to the load torque M1 was 1.127.

The foregoing is only a preferred embodiment of this invention and it should be noted that modifications can be made by those skilled in the art without departing from the principle of the invention and these modifications should also be considered as the protection scope of the invention.

Claims (2)

1. The utility model provides a but space crank rocker mechanism of intermittent motion, its includes rocker, connecting rod, crank and frame, its characterized in that: the rocker and the frame form a first rotating pair, the crank and the frame form a second rotating pair, the rocker and the connecting rod form a first spherical pair, the connecting rod and the crank form a second spherical pair, the axis of the rocker is vertically crossed with the axis of the crank, the axis of the crank passes through the motion plane of the rocker, and the length relationship of each component in the space crank-rocker mechanism capable of intermittently moving is as follows:

and is

Wherein,ψ ₀is the maximum swing angle of the rocker arm₁Is the length of the rocker, s is the length of the frame, l₃Is the crank length, /)₂Is the length of the connecting rod, delta>0 and delta<< l₂；

Maximum swing angle of rockerψ ₀Length l of crank₃And the length of the rack s are in the following relation, tg: (ψ ₀/2) = l₃/ s。

2. The intermittently movable space crank-rocker mechanism of claim 1 wherein the axes of the first and second revolute pairs intersect perpendicularly.

Images