JPH04321857A - Rectilinear moving mechanism - Google Patents

Abstract

PURPOSE:To accomplish a rectilnear moving mechanism having high accuracy and high durability utilizing the oscillating crank motion of an oscillating rack and to enable high-accuracy interlocking of plural rectilinear moving mechanisms at the time of parallel use by projecting both end portions of an input shaft from a support to transmit the rotation to the outside. CONSTITUTION:When an input shaft 19 is rotated by a driving motor 30, an input gear is rotated, and gears 17A, 17b meshed with the gear are rotated so that the respective crankshafts 16A, 16B are driven and the respective oscillating racks 15A-15C make an oscillating crank motion with a designated phase difference. At this time, the teeth T2 are pressed to the teeth T1, and the respective crank shafts 16A, 16B and the respective cases 14L, 14R are moved in the longitudinal directions of fixed racks 12L, 12R by its reaction force. Each input shaft 19 is rotated in synchronization with the driving motor 30 through a connecting rod 32. The speed reduction output for one teeth (for pitch) of each teeth T1, T2 is obtained by one rotation of each crankshaft 16A, 16B.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motion mechanism that converts rotational input into linear motion, and more particularly to a linear motion mechanism suitable for parallel use.

0002

[Prior Art] Conventionally, the feed mechanisms of various machine tools are equipped with a linear motion mechanism that converts rotational input into linear movement (reciprocating movement). In order to meet the growing demand for technology, those with a simple configuration are used. This type of linear motion mechanism is
For example, a device using a rack and pinion and a linear guide as shown in FIG. 6 is known. In this mechanism, a pinion 1 is driven by a motor 3 while being engaged with a rack 2, and a movable table 4 to which the motor 3 is fixed is moved. This moving table 4 has linear guide rails 5A and 5B at both ends.
The robot is guided by the robot in order to minimize resistance to its movement.

0003

[Problems to be Solved by the Invention] However, in such a conventional linear motion mechanism, the drive unit (rack/
Since the pinion (pinion) is biased toward the linear guide rail 5A, there is a problem in that the movement of the movable table 4 is not smooth due to twisting, and its feeding accuracy is reduced.

On the other hand, it is conceivable to drive the moving platform 4 in a straight line at both ends using, for example, a plurality of parallel rack and pinion mechanisms, but in that case, a complicated interlocking mechanism may be provided or each pinion may be driven by an individual drive motor. It needs to be driven by For this reason, the linear movement mechanism has become larger, or the cost has increased due to synchronous control of the drive motor.

Furthermore, since the number of meshing teeth between the pinion 1 and the rack 2 or between the pin gear 4 and the rack 3 is small, the tooth surface pressure is high and the durability is low. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a linear movement mechanism that is small in size, has excellent durability, and can be easily interlocked when used in parallel.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention provides a passive rack having a plurality of teeth, a plurality of teeth having the same pitch as the teeth of the passive rack, each of which connects the teeth to the passive rack. a plurality of active racks facing each other, a plurality of crankshafts spaced parallel to each other and supporting the plurality of active racks while maintaining a predetermined phase difference and meshing with the passive racks; an input shaft that has both ends protruding from the support, inputs rotation from one end of the input shaft to make a rocking crank motion of the crankshaft; It is characterized by transmitting rotation to.

[0007]

[Operation] According to the present invention, when the crankshaft rotates, the plurality of active racks engage with the passive racks while maintaining a predetermined phase difference and undergo rocking crank motion, whereby at least one of the active racks engages with the passive racks. Push or move by receiving the reaction force. At this time, since the passive rack and the active rack have a large number of teeth meshing at the same time, the tooth surface pressure does not become too high, resulting in a highly durable linear movement mechanism. In addition, since both ends of the input shaft protrude from the support and transmit rotation to the outside, multiple units can be linked together with a simple connection when used in parallel, reducing machine size and cost. can be achieved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings. 1 to 5 are diagrams showing an embodiment of a linear motion mechanism according to the present invention. First, the configuration will be explained. In FIGS. 1(a) and 1(b), reference numeral 11 denotes a movable table, and 12L and 12R denote two fixed racks (passive racks) fixed to the installation surface F at a distance from both left and right ends of the movable table 11. Each fixed rack 12L, 1
2R has grooves 12a on both side surfaces, and this groove 1
A pair of left and right cases 14L and 14R (support bodies) supporting the movable table 11 are coupled to the fixed racks 12L and 12R via a plurality of balls 13 that engage with the balls 13 so as to be movable only in the axial direction. In addition, as shown in FIGS. 2 to 4, the cases 14L and 14R include a fixed rack 12L or 12
A plurality of (for example, three) swinging racks 15A, 15B, and 15C (active racks) that mesh with R are housed, and the swinging racks 15A to 15C include fixed racks 12L,
A plurality of teeth T2 having the same pitch as the teeth T1 of 12R are formed. In addition, the teeth T1 of the fixed racks 12L and 12R
are formed into a tooth profile with a waveform (specifically, a trochoidal curve or a cycloidal curve) as shown in FIG. They are formed into arcuate tooth shapes with the same radius.

The swinging racks 15A to 15C are supported by eccentric cam portions 16a, 16b, and 16c of a pair of crankshafts 16A and 16B so that the teeth T2 sides thereof face and mesh with the fixed racks 12L and 12R, respectively. , these crankshafts 16A, 16B each have a pair of bearings 21, 2.
It is rotatably supported by cases 14L and 14R via 2. In addition, the eccentric cam portions 16a to 16c of the crankshafts 16A and 16B are formed, for example, at equal angular intervals (120° intervals since the number of swing racks is 3), and are connected to one end side of the crankshafts 16A and 16B. gear 17A,
When 17B rotates, the plurality of swing racks 15A to 15
C makes an oscillating crank motion while maintaining the predetermined phase difference (120°). Furthermore, the input gear 18 is meshed with the gears 17A and 17B, and the input gear 18 is connected to the bearings 23 and 24.
The input shaft 19 is connected to an input shaft 19 which is pivotally supported by the cases 14L and 14R.

[0010] The input shaft 19 is connected to the swing racks 15A to 15C.
The input shaft 19, which protrudes from the case 14R to the left in FIG. The rotation from the drive motor 30 is inputted to drive the plurality of crankshafts 16A, 16B. Further, a connecting rod 32 is connected to the other end of the input shaft 19 via a coupling 31, and the input shaft 19 protruding outward from the case 14L is connected to the connecting rod 32 via a coupling 33. are connected at one end. That is, the input shaft 19 inputs rotation from one end thereof, and the input gear 1
8 and a plurality of swing racks 1 via gears 17A and 17B.
5A to 15C are made to perform rocking crank motion, and their own rotation is transmitted to the outside from the other end.

Note that in FIGS. 2 and 3, 25, 26,
27 is the swing rack 15A to 15C and the crankshaft 16A,
It is a needle bearing interposed between eccentric cam parts 16a, 16b, and 16c of 16B, and 14a and 14b are circulation passages for the balls 13. Next, the effect will be explained. When the input shaft 19 rotates in one direction or the opposite direction due to the power from the drive motor 30, the input gear 18 rotates, and the gears 17A and 17B that mesh with the input gear 18 rotate in the same rotation direction, thereby causing the crankshaft 16A to rotate. , 16B
is driven, and the plurality of swing racks 15A to 15C perform swing crank motion while maintaining a predetermined phase difference.

At this time, as the crankshafts 16A and 16B rotate, the swing racks 15A to 15C respectively swing eccentrically as shown in FIGS. 5(a) to 5(c), and the teeth T2
One side of the tooth T1 is pressed against the crankshafts 16A, 16B and the case 14L due to the reaction force.
14R is moved in the longitudinal direction of fixed racks 12L and 12R. Further, since the swing racks 15A to 15C perform swing crank motion while maintaining a predetermined phase difference (120°) corresponding to the number of swing racks, the swing racks 15A to 15C are always rotated while the crankshafts 16A and 16B are rotating. At least one of them
comes into contact with the inclined surface on one side of the tooth T1 in the straight direction, and due to the rocking of the active rack, the cases 14L and 1
4R is pushed and moved in the longitudinal direction of the fixed racks 12L and 12R. Therefore, when the crankshafts 16A, 16B make one revolution, the cases 14L, 14R move one of the teeth T1, T2.
The moving base 11 moves slowly by the tooth (pitch).

In this moving state, the left and right cases 14
Since the two input shafts 19 projecting outward from L and 14R are connected via the connecting rod 32, both input shafts 19 are interlocked to rotate synchronously with the drive motor 30. Also, due to the crank motion of the swing racks 15A to 15C, one rotation of the crankshafts 16A and 16B causes one of the teeth T1 and T2 to rotate.
A deceleration output corresponding to the tooth (pitch) can be obtained. therefore,
There is no need to separately install a reducer, etc., and there is no need to install drive motors on the left and right sides.Moreover, the left and right cases 14L,
Rotation that synchronizes the 14R with high precision can be obtained, and a compact and highly accurate linear movement mechanism can be realized.

Further, the swing racks 15A to 15C mesh with the fixed racks 12L and 12 through a plurality of teeth T2 arranged in an appropriate number in the longitudinal direction of the fixed racks 12L and 12R. The tooth surface pressure can be small. Therefore, a linear movement mechanism with large thrust and excellent durability can be realized. As described above, in this embodiment, when a plurality of fixed racks 12L and 12R are arranged in parallel and a plurality of linear movement mechanisms are used in parallel, the plurality of fixed racks 12L and 12R can be connected with high precision using only a simple connecting member such as the connecting rod 32. This allows the machine to be made smaller and reduce costs.

[0015]

Effects of the Invention According to the present invention, a highly accurate and highly durable linear motion mechanism that utilizes the swinging crank motion of a swinging rack is realized, and both ends of the input shaft are made to protrude from the support body to allow external movement. By transmitting rotation to the machine, when used in parallel, multiple linear motion mechanisms can be linked with high precision with just a single drive source and simple connection, making it possible to downsize and reduce the cost of the machine.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of an embodiment of a linear motion mechanism according to the present invention, in which (a) is a plan view thereof, and (b) is a front view thereof.

FIG. 2 is a side sectional view of a main part of one embodiment.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a sectional view taken along line BB in FIG. 2;

FIG. 5 is an explanatory diagram of straight-ahead motion in one embodiment.

FIG. 6 is a plan view of a conventional example.

[Explanation of symbols]

11 Moving table 13 Balls 12L, 12R Fixed rack (passive rack) 14
L, 14R Case (support) 15A to 15C
Swing rack (active rack) 16A, 16B
Crankshaft 19 Input shaft 30 Drive motor 32 Connecting rods T1, T2 Teeth

Claims (1)

[Claims] Claims: 1. A passive rack having a plurality of teeth; a plurality of active racks each having a plurality of teeth having the same pitch as the teeth of the passive rack; each tooth facing the passive rack; a plurality of crankshafts that support a plurality of active racks while maintaining a predetermined phase difference and mesh with the passive racks, a support body that rotatably supports the crankshafts at both ends, and both ends protruding from the support body. an input shaft that inputs rotation from one end of the input shaft to cause the crankshaft to make a rocking crank motion, and transmits the rotation to the outside from the other end of the input shaft. Movement mechanism.