JPH09112644A - Linear motion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motion device of small construction at a low cost in which a cogged rail is installed, whose overall width is approx. the same as the cog width. SOLUTION: A linear motion device concerned is equipped with a cogged rail 40, a linear driving mechanism 50 having output members 53A-53C and a case 51 for accommodating them, and case guide means 31, 32, wherein the rail 40 has a plurality of cogs furnished at a certain pitch along the rail axis and includes a rail body 42 which is provided with a plurality of mesh regions apart from one another at a certain spacing as several times as great as the cog pitch and with a notch 46 to mount the rail 40 on another member between the regions. The output members 53A-53C mesh with the mesh region on the cogged rail 40 at a mesh division distance capable of simultaneous meshing with at least one cog T1 in adjoining two of a plurality of mesh regions 53A-53C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motion device for converting a rotary motion input to perform a linear motion, and more particularly to a linear motion device utilizing a toothed rail forming a substantially linear trajectory.

[0002]

2. Description of the Related Art A linear motion device for converting a rotary motion into a linear motion is frequently used in a feed mechanism of a machine tool and various transport devices. This linear motion device includes a device that linearly moves in the direction of the rotary input shaft and a device that linearly moves in a direction perpendicular to the rotary input shaft.Either type is small in size to meet the demand for miniaturization of the entire machine. A light-weight and simple-structured one is preferable.

[0003] Among the conventional linear motion devices, those that linearly move in the direction of the rotation input shaft by means of a ball screw are described below.
It is known that it can withstand high loads due to its high linear feed accuracy.However, it is necessary to machine the rotatable screw shaft for a long time with high precision, and to support the both ends and rotate it from one end. It is difficult to apply to a reciprocating motion having a stroke longer than a certain extent, and even if it can be applied, it must be very expensive.

On the other hand, a linear motion device using a rack and a pinion or a rack and a toothed belt has a high response,
Although it is easy to apply to a long stroke reciprocating motion and can be manufactured at low cost, it is inferior to a ball screw in terms of feed accuracy, load resistance and durability. Therefore, recently, using an oscillating type active rack and a toothed rail that forms a substantially straight track (including a gently curved track), it has been used for a considerably long load (or even on a gently curved endless track). There has been proposed a device that can endure and perform a substantially straight movement while maintaining a high feed accuracy.

[0005] Figures 4-6 show a was made of improvements to the assembly property and motion characteristics of this type of linear motion device, FIG 4 is a plan view, FIG. 5 A ₂ -A in FIG. 4 ₂ sectional view, a B ₂ -B ₂ sectional view of FIG. 6 FIG. As shown in these figures, this linear motion device includes a toothed rail 10 that also serves as a passive rack and a guide rail, and a linear drive mechanism 20 that performs linear motion relative to the toothed rail 10. Toothed rail 10
Has a plurality of teeth 11 and a plurality of bolt holes 12 for fixing the rail 10 to a support (not shown). Bolt hole 12
Are provided on both sides in the tooth width direction outside the tooth width region of the tooth 11 of the toothed rail 10, and the tooth width direction both sides of the toothed rail 10 in which the bolt holes 12 are formed have the tooth 11 on the upper surface in the drawing. It has a shape lower than the tooth base to allow mounting of a bolt (not shown). The linear drive mechanism unit 20 includes a case 21 and
It has a plurality of swing plates 22A, 22B, 22C which are housed in the case 21 and mesh with the teeth 11 of the toothed rail 10.
The teeth 23 of 22A to 22C have a tooth profile with the same pitch as the pitch of the teeth 11 of the toothed rail 10. These swing plates 22A to 22C are supported by the case 21 via crankshafts 24 and 25,
One crankshaft 24 is an input shaft driven by a drive motor (not shown). And this crankshaft 24
Of the crankshafts 24 and 25, the oscillating plates 22A to 22C circularly move in parallel with each other while maintaining a predetermined phase difference in the case 21 (hereinafter, this motion state is simply oscillated). However, the case 21 and the toothed rail 10 are relatively moved in the longitudinal direction of the toothed rail 10 by engaging with the teeth 11 of the toothed rail 10.

Reference numerals 31 and 32 denote case guide means for guiding the case 21 so as to be movable relative to the toothed rail 10 on both sides in the tooth width direction of the toothed rail 10. These case guide means 31, 32
Guides the case 21 only in the longitudinal direction (axial direction) of the toothed rail 10, and the guide means 31 is a toothed rail.
A guide groove portion 33 formed on one side surface portion of 10, a ball circulating portion 34 provided on one side plate portion of the case 21, and a guide groove portion 33.
And a plurality of circulating balls 35 that engage with the ball circulating portion 34.
And Similarly, the guide means 32 includes a guide groove portion 37 formed on the other side surface portion of the toothed rail 10, a ball circulation portion 38 provided on the other side plate portion of the case 21, a guide groove portion 37, and a ball circulation portion. It has a plurality of circulating balls 39 interposed between the portion 38 and the portion 38.

In the above structure, when the crank shaft 24 is driven by a drive motor (not shown), the crank shaft 24,
The swing plates 22A to 22C supported by 25 swing while maintaining the predetermined phase difference. At this time, one of the rocking plates 22A to 22C, for example, the rocking plate 22A, moves in a rocking range (for example, 0
In the range from 180 degrees to 180 degrees), the other swing plates 22B, 22
While keeping the phase difference with C constant, the tooth 23 is moved to the farthest position from the central axis of the toothed rail 10 to bring the tooth 23 into contact with the top of the tooth 11, and then one of the inclined surfaces of the tooth 11 is pushed. While approaching the center axis of the toothed rail 10 and further approaching the center axis of the toothed rail 10, the root reaches the valley between the roots of the teeth 11. This operation is the same for the other swing plates 22B and 22C.
Since 22A to 22C oscillate while maintaining the predetermined phase difference,
One of the swing plates 22A to 22C always presses the tooth 11 with the tooth 23.

On the other hand, in such a state, the toothed rail 10 and the case 21 are guided by the guiding means 31 and 32.
Is guided so as to relatively move only in the longitudinal direction, so that either the case 21 or the toothed rail 10 (movable side) moves only in the predetermined straight traveling direction. That is, the swinging plates 22A to 22C alternately approach the central axis of the toothed rail 10 while pressing one slope of the tooth 11, thereby providing a toothed rail.
Thrust acts in the longitudinal direction of 10. Then, the case 21 relatively moves in the longitudinal direction of the toothed rail 10 by one pitch of the teeth 11 per rotation of the crankshafts 24, 25,
The moving part to which is attached moves slowly at a predetermined speed.

[0009]

However, even in the above-described improved linear motion device, a bolt hole for attaching the toothed rail 10 to another fixed-side or movable-side member.
Since 12 is provided on both sides in the tooth width direction outside the tooth width region of the tooth 11 of the toothed rail 10, the toothed rail 10 is wide and the case 21 is wide and large, and the recent small size, We were unable to meet the demand for weight reduction.

Further, since it is necessary to perform step processing so that both side portions in the tooth width direction of the long toothed rail 10 are lower than the teeth 11, the cost of the apparatus is increased. Therefore, the present invention realizes a toothed rail mounting structure which can be mounted almost in the same manner as the conventional one, and further, the toothed rail can be made to have the full width of the tooth width, and a small-sized, low-cost linear motion device. The purpose is to provide.

[0011]

In order to achieve the above object, the invention according to claim 1 has a toothed rail having a plurality of teeth having a predetermined pitch, and a plurality of output teeth meshing with the teeth of the toothed rail. A linear motion device including a linear drive mechanism having an output member formed with a groove and a case accommodating the output member, and guide means for guiding the case so as to be movable relative to the toothed rail. A plurality of meshing tooth regions, each of which has a plurality of teeth arranged in the axial direction of the toothed rail at the predetermined pitch and is spaced apart from each other at a plurality of the predetermined pitch, and a plurality of meshing tooth regions. A rail body having a mounting notch portion for mounting the toothed rail to another member between the meshing tooth regions,
The output member meshes with the meshing tooth area of the toothed rail with a meshing section distance that allows simultaneous meshing with at least one meshing tooth of each of two adjacent meshing tooth areas of the plurality of meshing tooth areas. Therefore, it is not necessary to provide bolt holes or the like on both sides of the toothed rail in the tooth width direction for mounting, and it is possible to reduce both the width dimensions of the toothed rail and the case. Further, by providing the mounting notch outside the meshing tooth area, the machining for mounting the toothed rail can be greatly facilitated and the number of machining steps for the tooth profile of the meshing tooth can be reduced. become.

Further, according to a second aspect of the present invention, the mounting notch is formed as a through hole penetrating the rail main body in a direction substantially orthogonal to the meshing tooth region, and the toothed rail is provided. The plurality of teeth may have a tooth width larger than the hole forming width of the through hole. In that case,
Since the mounting notch is a through hole, processing is simple.

Further, as in the invention described in claim 3,
The straight-movement drive mechanism section oscillates a plurality of oscillating plates having a plurality of teeth having substantially the same pitch as the teeth of the toothed rail, and the teeth of the oscillating plates are parallel to each other and maintain a predetermined phase difference. A plurality of rotatable crank shafts that engage with the rocking plate, and the rocking plate is supported in parallel with the toothed rails via the crank shafts, and the rocking plate is housed inside. A case is provided, and the rotation of the crankshaft is converted into relative movement between the case and the toothed rail, and each tooth in the meshing tooth area of the toothed rail has a tooth width that meshes with a plurality of oscillating plates. Good. In that case, the device can withstand a large load and can perform a substantially straight movement while maintaining a high feed accuracy.

The mounting notch may be a bolt hole having an arbitrary hole shape, but is not limited to such a hole, and for example, at least the upper and lower surfaces on one side in the tooth width direction of the toothed rail. Alternatively, a concave cutout opening on the side surface may be used. Further, the mounting notch is a groove or concave notch having a pressing surface for pressing against the installation surface by a pressing member, or a flat plate portion (a plate-shaped rail main body portion without only meshing teeth). You can also That is, the attachment notch is a portion where at least one tooth of the meshing tooth is cut out as compared with the meshing tooth region.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3
3 is a diagram showing an example of a preferred embodiment of the present invention, FIG. 1 is a plan view thereof, FIG. 2 is a sectional view taken along line A ₁ -A _{1 of} FIG. ₁ , FIG.
FIG. 3 is a B ₁ -B ₁ sectional view of FIG. 2. The same or corresponding members as those in the conventional example are designated by the same reference numerals, and different configurations will be mainly described.

First, as shown in FIGS. 1 to 3, this linear motion device has a toothed rail 40 having a plurality of teeth T ₁ having a predetermined pitch and forming a linear track, and a toothed rail 40 along the toothed rail 40. The linear drive mechanism 50 provided so as to move relative to this and the case of the linear drive mechanism 50 on both sides in the tooth width direction of the toothed rail 40.
Guide means 31 and 32 for guiding 51 relative to the toothed rail 40 are provided.

The toothed rail 40 has, for example, a plurality of parallel columnar pins 41 arranged in the longitudinal direction of the toothed rail 40 so as to form the tooth T ₁ , and these pins 41 are rotated about their respective axes. A plurality of parallel arcuate groove portions 42a for holding as much as possible
And a restraining plate 43 having an L-shaped cross section that engages with both ends of the pin 41 so as to restrict movement of each pin 41 other than rotation within the arc groove portion 42a. It should be noted that it is advisable to attach a lubricant around the pin 41 under heavy load, but for small size and light load applications, a lubricating coating is formed on the outer periphery of the pin 41 or the arc groove 42a of the rail body 42. Alternatively, the pin 41 can be formed of a material having a high self-lubricating property.

Further, the toothed rail 40 has a plurality of meshing tooth regions 45.
have. The meshing tooth regions 45 are formed by a plurality of teeth T arranged in the axial direction of the toothed rail 40 at a predetermined pitch.
_One pair of adjacent meshing tooth regions 45 are arranged so as to be spaced apart in the axial direction of the toothed rail 40 at intervals of a plurality of pitches of the teeth T ₁ . Specifically, the rail main body 42 of the toothed rail 40 has a rectangular cross section, and a plurality of parallel circular arc groove portions 42a are provided on one surface portion (upper surface portion in FIG. 2) of each tooth with an interdental pitch of one tooth. The rail main body 42 has a plurality of arc grooves 42a, and a plurality of pins 41 are attached to the rail body 42 so that the inter-tooth pitch is doubled for every three teeth T _1. A plurality of meshing tooth regions 45 are arranged on the main body 42 at predetermined intervals.

Further, a plurality of meshing tooth regions of the toothed rail 40
Between the portions 45, mounting notches 46 for mounting the toothed rails 42 to other members are formed. In the present embodiment, the mounting notch 46 is the rail body.
It has a plurality of pairs of bolt holes 42b (through holes) penetrating in a direction substantially orthogonal to the tooth surface of each meshing tooth region 45 of 42, and is adjacent to each other in the longitudinal direction (axial direction) of the toothed rail 40. A pair of circular bolt holes 42b spaced apart in the tooth width direction of the toothed rail 40 are formed in parallel in the middle of any two meshing tooth regions 45. Further, the plurality of teeth T ₁ of the toothed rail 40 have a tooth width Wt larger than the maximum diameter d of the bolt hole 42b, and this tooth width Wt is the formation width w of the pair of holes 42b (in the case of a single hole, Has a larger tooth width. In addition, bolt holes
42b can be provided in any number, not in each pair, and need not be the same size or shape.

The linear drive mechanism section 50 includes a case 51 having a plurality of shaft holes 52a and 52b arranged on parallel axes, and a plurality of teeth T ₂ (outputs) having substantially the same pitch as the teeth T ₁ of the toothed rail 40. A plurality of oscillating plates 53A, 53B, 53C (output members) each having a tooth) and meshing with the meshing tooth area 45 of the toothed rail 40, and each oscillating plate 53A engaged with these oscillating plates 53A to 53C. a tooth T ₂ of the ~53C is a plurality of crankshaft 54 and 55 rotatable for holding the oscillating plate 53A~53C to swing kept parallel to and a predetermined phase difference from each other by a predetermined eccentricity, the ing. Swing plate 53
A to 53C are housed in, for example, the case 51, and are supported in parallel by the case 51 via the crankshafts 54 and 55 so that the teeth T ₁ face the toothed rail 40. The teeth T ₂ of the oscillating plates 53A to 53C have, for example, a trochoidal curve shape or a cycloidal curve shape. The swing plates 53A to 53C are supported on the crankshafts 54 and 55 via needle bearings 56a, 56b and 56c, respectively,
Both crankshafts 54, 55 are supported by the case 51 via a pair of bearings 57a, 57b. Further, since the swing plates 53A to 53C are assembled to the crankshafts 54 and 55, the swing plates 53A to 53C are
A large-diameter hole is formed in the oscillating plate 53 arranged in the center of the two, and the smaller-diameter holes are formed in the remaining oscillating plates 52 and 54, respectively. Of the eccentric cam portions 54a, 54b, 54c of the shaft 54, the central eccentric cam portion 54b is formed to have a larger diameter than the remaining eccentric cam portions 54a, 54c on both sides, and the central eccentric cam portion 55b of the other crankshaft 55. Similarly, the diameter is larger than the eccentric cam portions (not shown) on both sides.

The linear drive mechanism 50 includes swing plates 53A to 53A which form a parallel link with the crankshafts 54 and 55 when one crankshaft 54 is rotated by an external power.
The 53C is circularly moved (swinged) in parallel with each other while maintaining a predetermined phase difference, and the case 51 and the toothed rail 40 are relatively moved in the central axis direction of the toothed rail 40. That is, the linear drive mechanism unit 50 converts the input rotation to the crankshaft 54 into the relative movement of the case 51 and the toothed rail 40 in the predetermined linear direction by the crankshafts 54 and 55 and the swing plates 53A to 53C. It is designed to function as a motion conversion mechanism.

On the other hand, the teeth T ₂ of the oscillating plates 53A to 53C can be simultaneously meshed with at least one meshing tooth T ₂ of each of two meshing tooth areas 45 adjacent to each other among the meshing tooth areas 45. It meshes with the meshing tooth region 45 of the toothed rail 40 at a distance L. Then, during relative movement between the case 51 and the toothed rail 40, as shown in FIG. 2, any tooth T ₂ of the oscillating plates 53A to 53C is disengaged from the tooth T _{1 of} one meshing tooth region 45. Prior to any one of the rocker plates 53
A, the teeth T ₁ of the 52B or 53C meshing teeth region 45 teeth T ₂ is next to the
It engages with and makes a continuous rectilinear movement.

The case 51 has a pair of side plate portions 61 and 62 extending parallel to both sides of the toothed rail 40 in the tooth width direction and both sides of the swing plates 53A to 53C in the longitudinal direction of the toothed rail 40. It has a pair of end plate portions 63 and 64 which are located and which connect both end portions of the pair of side plate portions 61 and 62 to each other. Also,
With the plurality of swing plates 53A to 53C assembled to the crankshafts 54 and 55 via the needle bearings 56a, 56b and 56c, the crankshafts 54 and 55 can be rotatably supported via the bearings 57a and 57b. Further, the case 51 is divided into a pair of upper and lower substantially rectangular frame bodies, first and second segments 511 and 512, and the segments are connected by a plurality of bolts 513.

In the linear motion device of the present embodiment having the above structure, when the crank shaft 54 is driven by a drive motor (not shown), the swing plates 53 supported by the crank shafts 54, 55
While thrusting the inclined surfaces of the teeth T ₂ against the teeth T ₁ of the toothed rail 40 while the A to 53C swing while maintaining a predetermined phase difference, the thrust in the longitudinal direction of the toothed rail 40 described above is obtained. Occurs.

In this way, when a thrust force is generated as the swing plates 53A to 53C swing, the teeth T _{2 of the} swing plates 53A to 53C and the teeth T ₁ of the toothed rail 40 are contacted at a plurality of contact portions. The contact pressure acts on each of them, but the teeth T ₂ of each rocking plate 53A to 53C are always a predetermined number of toothed rails 40 (for example, three as shown in FIG. 2).
Since it meshes with the meshing teeth T ₁ described above, the toothed rail 40 has a plurality of meshing tooth regions 45 and mounting notches 46.
Even if a portion without the meshing tooth T ₁ is formed at every predetermined interval by providing, the excessive contact pressure does not act on each tooth surface, and there is no hindrance to the continuous linear movement.

Moreover, the toothed rail 40 has a notch for mounting.
By providing 46 between the adjacent meshing tooth regions 45, it is not necessary to provide bolt holes or the like for attachment on both outer sides of the tooth width region. That is, the plurality of teeth T of the toothed rail 40
_Since the tooth width Wt of _{1 has} a tooth width larger than the formation width w of the pair of holes 42b (hole diameter in the case of a single hole), the toothed rail 40
And the width of the case 50 can both be reduced,
In addition, the step of machining the toothed rail 40 as in the conventional case is not required, and thus the machining of the toothed rail 40 is greatly facilitated. Furthermore, the arc groove formed in the rail body 42 of the toothed rail 40
The number of 42a and the number of pins 41 arranged are also small. Needless to say, when the toothed rail is formed as an integral part, the number of man-hours for processing the tooth profile of the meshing tooth T ₁ is reduced.

Further, the mounting notch 46 is provided on the rail main body 42.
Since the pair of holes 42b that are substantially orthogonal to the meshing tooth region 45 are provided, the mounting notch 46 can be easily machined. Furthermore, the linear drive mechanism 50, a plurality of swinging plates having teeth T ₁ and a plurality of teeth T ₂ of the substantially the same pitch of the toothed rail 40 53A
And 53C, a plurality of crankshaft 54 rotatable to engage these so that the teeth T ₂ of the swing plate 53A~53C swings kept parallel and a predetermined phase difference from each other, both the crankshaft 54 ，
A case in which the rocking plates 53A to 53C are supported in parallel to the toothed rail 40 via 55 and are housed inside.
51, which converts the rotation of the crankshafts 54, 55 into relative movement between the case 51 and the toothed rail 40, and
Each tooth T ₂ of the meshing tooth region 45 of 40 has a plurality of swing plates 53A to 53C.
Since it has a tooth width Wt that meshes with each other, the device has a sufficiently large number of meshing teeth, and is capable of withstanding a large load and performing substantially straight movement while maintaining high feed accuracy. As a result, it is possible to maintain a highly accurate straight feed accuracy, and it is possible to sufficiently meet the recent demands for downsizing and cost reduction.

[0028]

According to the first aspect of the present invention, it is not necessary to provide a bolt hole or the like outside the tooth width of the toothed rail for mounting, and the width dimensions of the toothed rail and the case are both reduced. It is possible to facilitate the processing for attaching the toothed rail and the processing for forming the tooth profile. As a result, it is possible to provide a linear motion device which can be mounted in substantially the same manner as the conventional one, and which is small in size, lightweight, and low in cost, in which the toothed rail has a full width of about its tooth width.

Further, according to the second aspect of the present invention, since the through hole penetrating in the meshing tooth area in a direction substantially orthogonal to the meshing tooth area is formed, the machining of the mounting notch can be simplified. You can Further, according to the invention as set forth in claim 3, there is provided a linear drive mechanism section having a plurality of swing plates for converting the rotation of the crankshaft into the relative movement of the case and the toothed rail, and the meshing tooth area of the toothed rail. Since each tooth has a tooth width that meshes with the plurality of oscillating plates, it is possible to provide a device that can withstand a large load and can perform a substantially straight movement while maintaining high feed accuracy. .

[Brief description of the drawings]

FIG. 1 is a plan view of a rectilinear motion device showing an example of a preferred embodiment of the present invention.

FIG. 2 is a sectional view taken along line A ₁ -A _{1 of} FIG.

FIG. 3 is a sectional view taken along line B ₁ -B ₁ of FIG. 1;

FIG. 4 is a plan view of a conventional example.

5 is a sectional view taken along line A ₂ -A _{2 of} FIG.

6 is a B ₂ -B ₂ sectional view of FIG.

[Explanation of symbols]

31, 32 Guide means 40 Toothed rail 41 Pin 42 Rail body 42a Arc groove 45 Meshing tooth area 46 Notch for mounting 50 Linear motion mechanism 51 Case 53A, 53B, 53C Oscillating plate (output member) 54, 55 Crank Shaft T ₁ meshing tooth T ₂ meshing tooth (output tooth)

Claims (3)

[Claims] 1. A linear drive mechanism having a toothed rail having a plurality of teeth of a predetermined pitch, an output member having a plurality of output teeth formed to mesh with the teeth of the toothed rail, and a case accommodating the output member. And a guide means for guiding the case so as to be movable relative to the toothed rail, wherein the toothed rails are arranged at the predetermined pitch in the axial direction of the toothed rail. A plurality of meshing tooth regions each of which is formed of a plurality of teeth and is spaced apart from each other by a plurality of the predetermined pitches, and an attachment for mounting the toothed rail to another member between the plurality of meshing tooth regions. A rail main body in which a notch portion is formed, and the output member can simultaneously mesh with at least one meshing tooth of each of two adjacent meshing tooth areas of the plurality of meshing tooth areas. A straight-moving device that meshes with a meshing tooth area of the toothed rail with a certain meshing section distance. 2. The notch for mounting is formed as a through hole penetrating the rail main body in a direction substantially orthogonal to the meshing tooth region, and a plurality of teeth of the toothed rail are formed as holes of the through hole. The linear motion device according to claim 1, having a tooth width larger than the width. 3. The linear drive mechanism section comprises a plurality of oscillating plates having a plurality of teeth having substantially the same pitch as the teeth of the toothed rail, and the teeth of the oscillating plates are parallel to each other and have a predetermined phase difference. A plurality of rotatable crankshafts that engage with the rocking plate so that the rocking plate is rocked, and the rocking plate is supported in parallel with the toothed rail through the crankshafts while facing the rocking plate. A case for accommodating a plate therein, and converting rotation of the crankshaft into relative movement between the case and the toothed rail, and each tooth in the meshing tooth area of the toothed rail has a linear drive mechanism. The linear motion device according to claim 1, wherein the linear motion device has a tooth width that meshes with a plurality of swing plates of the section.