JPH05187507A - High speed linear-motion mechanism - Google Patents

Abstract

PURPOSE:To provide a linear-motion mechanism with small backlash which can bear a heavy load. CONSTITUTION:Plural number of discs 22 are mounted on passive racks 20, 21 as they can be rotated by an input gear 25, two roller supporting pins 27 are implanted in each disc 22, and rollers 23 are rotatably mounted on the roller supporting pins 27 through bearings 24. Two discs 22 are arranged at an interval of three fourth of a lead of the passive rack, 20, 21 and meshed with each other through the input gear 25 as the roller supporting pins 27 of both discs 22 make phase difference of 90 deg.. The paired passive racks 20, 21 have wave-shaped teeth 20a, 21a, respectively, and rollers 23 of the discs 22 are sandwiched between a pair of the passive racks 20, 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, drive of a transport machine, drive of a traveling axis of a traveling robot, drive of a direct robot,
The present invention relates to a linear motion mechanism that is widely used for driving a positioning table, a clamp, a lift shaft of a forklift, and the like, and converts a rotary motion into a linear motion, and particularly to a linear motion mechanism that can operate at high speed.

[0002]

2. Description of the Related Art Conventionally, as a device for converting a rotational motion into a linear motion, for example, as shown in FIG. 1, a rack 2 having a large number of teeth 2a formed on the side surface of a linear member, and the rack 2 Pinion 1 (gear) having a large number of meshing teeth 1a
A rack and pinion mechanism consisting of is known. Further, as shown in FIG. 2, there is known a pin gear device including a rack 3 having corrugated teeth 3a and a pin gear 4 in which a large number of pins 4a meshing with the rack 3 are planted in a disc.

In the conventional linear motion mechanism as described above, the rack and pinion tooth surfaces are slid by the rack and pinion tooth surfaces or the rack tooth surface and the pin on the disk. There is a problem of wear.

Further, one tooth of the pinion or one of the discs
Since the pins of the book mesh with the teeth of the rack, there is a problem that the backlash between the rack and the pinion and the backlash between the rack and the pin of the disk are large, and the transmission efficiency is reduced.

Further, in the above-described pin rack structure, it is necessary to implant four or more pins on the disk due to the structure, and on the other hand, if the pin thickness is thin in order to mesh the rack teeth with the pins. There is no choice but to avoid the problem that a large load cannot be transmitted.

In view of the problems of the conventional device as described above, the present applicant has previously proposed a passive rack 11 having a corrugated tooth profile as a linear motion mechanism having a small backlash and capable of withstanding a large load. A straight advance characterized by comprising a plurality of discs 12 rotatably arranged at predetermined intervals while maintaining a phase difference, and a plurality of pin members equidistantly arranged around the rotation center of the discs on each disc 12. A motion mechanism was proposed (see Fig. 3).

Further, in the proposed apparatus, the disc 1
It is preferable that the pin member provided in 2 is rotatably supported. As a method of rotatably supporting the pin member, a support 17 may be implanted in the disk 12 and the roller 13 may be rotatably supported on the support 17 via a bearing 14, or a support pin may be supported on the disk via a bearing. It is also possible to rotatably support. By thus rotatably supporting the pin member that meshes with the rack, the rack and the pin member become rolling transmissions, and wear resistance is greatly improved, and transmission efficiency is also greatly improved.

Further, in the proposed apparatus, two disks are used.
It is preferable that two disc members are provided symmetrically with respect to the center of rotation on the disc, and both discs have a phase difference of 90 °. By doing so, it becomes possible to transmit a large force.

[0009]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In the previously proposed mechanism for converting rotational movement into linear movement, the disk 12 is
Even if the passive rack 11 rotates, the passive rack 11 moves only for the lead, and in order to increase the moving speed of the passive rack 11, the disk 1
There is no choice but to increase the rotation speed of 2 or increase the lead of the passive rack 11. However, even if an attempt is made to increase the rotation speed of the disk 12, there is a limit due to the reduction ratio of the speed reducer or the like. Further, if the lead of the passive rack 11 is increased, the size of the entire linear movement mechanism is increased.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rectilinear motion mechanism having a large rectilinear speed and a large rectilinear stroke.

[0011]

SUMMARY OF THE INVENTION In the present invention, a passive rack having a corrugated tooth profile, a plurality of disks rotatably arranged at a predetermined interval while maintaining a predetermined phase difference, are provided.
A plurality of pin members arranged equidistantly around the rotation center of the disc on each of the discs, and arranged so as to face the passive rack with the pin members of the disc sandwiched therebetween and having the same wavy shape as the tooth profile of the passive rack. It is achieved by a linear motion mechanism characterized by comprising a second passive rack having

[0012]

In the present invention, the passive racks are arranged on both sides of the disk, and the relative speed of one passive rack can be doubled with respect to the other passive rack.

[0013]

The present invention will be described in detail below with reference to the accompanying drawings. FIG. 3 shows a perspective view of an embodiment according to the present invention, in which a part of the cover part is removed. In FIG. 4, a linear passive rack 20 is fixedly supported, and a linear passive rack 21 is linearly interlocked with the passive rack 20 and supported via slide bearings (not shown). The passive racks 20 and 21 have the same wavy tooth profiles 20a and 21a on their surfaces, and these tooth profiles 20a and 21a are trochoidal curves or cycloidal curves as shown in FIG. Although the passive racks 20 and 21 and the corrugated member are shown as an integrated structure in FIG. 3, they are fixed to the surfaces of the passive racks 20 and 21 by corrugated members (not shown), bolts, or the like. Good. The passive rack 21 can move linearly with respect to the fixed passive rack 20 through a large number of bearings.

In FIG. 3, two discs 22 are rotatably supported at a lower middle position between the two passive racks 20 and 21, and a tooth profile 22a is formed on the peripheral surface of the disc 22. Mesh via the input gear 25.

The disk 22 has the same amount of eccentricity from the center of rotation, that is, symmetrically with respect to the center of rotation on a circle having a constant radius from the center of rotation, that is, with a phase difference of 180 °, a roller support pin 27. Is provided.

A bearing 24 is attached to the roller supporting pin 27.
The roller 23 is rotatably supported via. As described above, the roller support pins 27 are equidistantly symmetric with respect to the rotation center of the disc 22, that is, the rotation center of the disc support shaft 25. Further, the two adjacent discs 22 are arranged such that their centers are separated by a distance of 3/4 of the lead L of the passive racks 20 and 21, and the two discs 22 have a phase difference of 90 °. In this way, that is, when the roller support pins 27 on the same disk 22 are connected by an imaginary line, the two sets of disks 22 mesh with each other via the input gear 25 so that the imaginary lines of the two disks 22 are orthogonal to each other.

When the input gear 25 is rotated, the two sets of disks 22 meshing with the input gear 25 are moved to the input gear 25.
, And both disks 22 rotate in the same direction,
The roller 23 provided on the disk 22 is the passive rack 2
Since the passive rack 20 is fixed by meshing with the tooth profiles of 0 and 21, the disk 22 moves linearly with respect to the fixed passive rack, and the passive rack 21 is further moved at a double speed and a double distance. At this time, the roller 23 and the passive racks 20 and 21
It is in rolling contact with the tooth profile of.

Further, in the above embodiment, the disk 22
Although the roller 23 is rotatably supported by the roller supporting pin 27 installed on the disk through the bearing 24, the pin may be rotatably supported by the disk 22 through the bearing (not shown). Furthermore, in special cases, the pins may be fixedly installed on the disk 22. Alternatively, the disk 22 may be rotated at a fixed position to linearly move the passive racks 20 and 21 in opposite directions.

[0019]

As described above, according to the present invention, since there are two sets of discs, a linear movement mechanism capable of enlarging a pin member provided on the discs and capable of withstanding a large load is provided. By incorporating a roller into the pin as shown in the embodiment, the transmission between the roller and the tooth profile of the rack can be a rolling transmission, and wear resistance and transmission efficiency can be greatly improved.

Further, since the pair of passive racks are engaged with the pin members from both sides of the disk, the distance traveled per input rotation is doubled as compared with the previously proposed device shown in FIG. Therefore, the speed (the relative speed between the passive racks 20 and 21) is doubled. In addition, compared to the proposed device of FIG.
Double the stroke.

[Brief description of drawings]

FIG. 1 is a plan view showing a conventional rack and pinion mechanism.

FIG. 2 is a plan view showing a conventional pin rack device.

FIG. 3 is a perspective view of the applicant's previous proposed device with the cover removed.

FIG. 4 is a perspective view of the embodiment of the present invention with a cover removed.

FIG. 5 is a diagram illustrating a tooth profile of the rack of the present invention.

[Explanation of symbols]

 20 Passive rack 21 Passive rack 22 Disc 23 Roller 24 Bearing

Claims (3)

[Claims] 1. A passive rack having a wavy tooth profile, a plurality of discs arranged to be rotatable at a predetermined interval while maintaining a predetermined phase difference, and each of the discs is equidistantly arranged around a rotation center of the disc. A plurality of pin members arranged, and arranged to face the passive rack with the pin member of the disk interposed therebetween,
A linear motion mechanism comprising a second passive rack having the same corrugation as the tooth profile of the passive rack. 2. The linear movement mechanism according to claim 1, wherein the pin member is rotatably supported by the disc. 3. The disk according to claim 1, wherein the number of the disks is two, each disk is provided with two pin members, and both disks have a phase difference of 90 °. Linear motion mechanism.