JP2592021Y2 - Linear motion mechanism - Google Patents

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 for converting a rotary motion into a linear motion, and more particularly to a small linear motion mechanism capable of generating a large thrust.

[0002]

2. Description of the Related Art In general, a linear motion mechanism for converting a rotary motion into a linear motion is frequently used as one of basic mechanical elements. For example, a linear rack is engaged with a disk-shaped pinion. A so-called rack and pinion mechanism is representative. This mechanism transmits the rotational motion of the pinion to the rack by meshing the gears and converts it into linear motion of the rack.However, the meshing area between the pinion and the rack is small, and in order to obtain a large thrust, the teeth of the rack and the pinion are required. There is a drawback that the width needs to be increased and the size cannot be avoided.

Therefore, the present applicant has previously described the "linear motion mechanism".
(Japanese Patent Application No. 4-333198, December 14, 1992)
Has been proposed. FIG. 4 is a conceptual configuration diagram thereof. 1 the input shaft is driven by an electric motor or the like, 2-4 rotating plate (at least three), K _2a ~K _2d are at least two in number that depends on the cylindrical sliding body (request thrust; FIG. Four examples) and 6 are rails on which irregularities having a curved surface (for example, cycloid teeth) are arranged at a predetermined pitch.

[0004] Incidentally, the roller may be attached to the rail side and the cycloid tooth profile may be formed on the rotating plate side. First eccentric crankshafts 7a to 7c having a phase difference of 120 degrees are integrally attached to input shaft 1, and these first eccentric crankshafts 7a to 7c are in phase with each other. Together with the eccentric crankshafts 8a to 8c, the three rotating plates 2 to 4 are rotatably held on an axis in a direction orthogonal to the rail 6.

The sliding bodies K _{2a to} K _2d are attached to the front rotating plate 2 at a predetermined pitch (however, the same pitch as the pitch of the unevenness of the rail 6). Sliding on the top (however, sliding bodies K _{2a to} K
_{If 2d} is a rotating body such as a wheel, it rolls). It should be noted that four sliding bodies are also attached to the intermediate and rear rotating plates 3 and 4 similarly to the front rotating plate 2. Hereinafter, the sliding body of the intermediate rotating plate 3 is denoted by the symbol K _3a.
The ~K _3d, also, the sliding body of the rotating plate 4 at the back shall reference numeral K _4a ~K _4d. That is, the codes K _{ia to} K _id
(Where i is a set number 2 to 4).

In such a configuration, as shown in FIG. 5, when the rotation angles of the input shaft are 0, 90, 180 and 270 degrees, the rotating plates 2 to 4 and the sliding body _Kia
~ _Kid (however, two consecutive characters are representative; for convenience, _Kia and K
_ib ) and the positional relationship between the irregularities of the rail 6 are as follows. Between the three rotating plates 2 to 4, the first and second rotating plates
The rotational phase difference of 120 degrees is given by the eccentric crankshafts 7a to 7c and 8a to 8c. For convenience, the rotation angles of the rotating plates 2 are used as a reference (that is, the phase difference from the input shaft 1 is zero), and the other rotating plates 3, 4
Are +120 degrees and +240 degrees, respectively, when the rotating plate 2 is at a predetermined position on the rail 6, the other rotating plates 3 and 4 are moved +12 degrees from the predetermined position.
It is at a position advanced by 0 degrees and +240 degrees. In other words, assuming that one pitch of the unevenness formed on the rail 6 is 360 degrees, the sliding body K _{ia is} shifted by １ ／ pitch (120 degrees).
The _Kib will come into contact with the irregularities.

Therefore, when a pair of sliding bodies K _ia and _Kib are in contact with the uneven ascending slope (reference numerals “a” to “e”)
), At least one other pair of sliding bodies K _ia , _Kib abuts on the downward slope of the unevenness (reference numerals “f” to
The thrust required to get over the climbing slope can be obtained from at least one other sliding body K _ia , K _ib .

That is, during one rotation of the input shaft 1, at least one set of sliding bodies K _{ia to} K _id always comes into contact with the downward slope of the unevenness, so that the propulsive force required to push the rail 6 is increased. , And a size corresponding to the axial length and number of the sliding bodies K _{ia to} K _id , thereby realizing a small and powerful linear motion mechanism.

[0009]

The sliding members K _{ia to} K _{ic of} the rotating plates 2 to 4 and the unevenness of the rail 6 always make relative movement while making contact with each other. Because it increases rolling friction and reduces efficiency,
Also, an excessively small contact pressure causes an increase in backlash, so that an appropriate pressure adjustment is required.

[0010] However, in the linear motion mechanism according to the above-mentioned prior application, only the pressure adjustment at the time of rest can be performed, and the abutment pressure at the time of motion may be inappropriate, resulting in reduced efficiency and backlash. In some cases. [Purpose] Accordingly, the present invention includes a plurality of rollers that can be elastically deformed so as to always maintain a proper contact pressure at the time of exercise, thereby lowering efficiency and increasing backlash. The aim is to provide a practical linear motion mechanism.

[0011]

In order to achieve the above object, the present invention provides a rail in which a number of rollers are arranged at a predetermined pitch and at least two rails arranged in the sliding direction at the same pitch as the rollers. At least three sets of sliding bodies that slide or roll on the rail, and a plurality of rotating plates that rotate in synchronization with the rotation of the input shaft, wherein the number of the rotating plates is the same as the number of sets of the sliding bodies At the same time, the rotation axis of each rotating plate is an axis in a direction orthogonal to the rail, and a predetermined phase difference is given to the rotating motion between the rotating plates, and further, one set of the sliding body is attached to each rotating plate. In the linear motion mechanism configured as described above, the plurality of rollers include a first roller having a predetermined diameter and high rigidity,
A second roller having a diameter larger than the diameter of the first roller and having low rigidity, wherein the second rollers are arranged at regular intervals.

[0012]

According to the present invention, an elastic force having a magnitude corresponding to the rigidity of the second roller (lower than the first roller) is interposed between the sliding member on the rotating plate side and the roller on the rail side. ,
A pressurization (preload) according to this elastic force is applied between the sliding body and the roller. Therefore, the fluctuation of the contact pressure during exercise is absorbed by the above-mentioned pressurization (elastic force), and is always maintained properly.
In addition, it is possible to provide a practical linear motion mechanism that does not cause an increase in backlash.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of the linear motion mechanism according to the present invention. The basic operation principle of the linear motion mechanism of each embodiment is the same as the linear motion mechanism (FIGS. 4 and 5) according to the prior application. The difference will be mainly described.

In FIG. 1A, reference numeral 10 denotes a rail. On the rail 10, a large number of rollers 11 are provided at a predetermined pitch.
These rollers 11 are a first roller 11a (shown by a white circle) having a predetermined diameter and a high rigidity, and a second roller 11a having a slightly larger diameter and a lower rigidity than the first roller 11a. (Shown by a black circle) 11b
Rollers 11b are arranged at regular intervals. Here, the second roller 11b may be formed of an elastic material such as a resin, for example. Alternatively, as shown in FIGS. 1B and 1C, a hollow pipe-shaped roller 11b 'and a body portion may be formed. Spring-like roller 11 vertically split and inflated to the outside
b ″ may be used.

12 is a rotating plate (however, at least 3
The rotating plate 12 is one of the rotating plates 2 to 2 of the linear motion mechanism according to the prior application.
4 (see FIG. 4), whereas the prior application has roller-shaped sliding bodies K _{ia to} K _id , whereas the rotating plate 12 of this embodiment has a curved surface. It is different in that it has a tooth profile (for example, a cycloid tooth profile). That is, the rotary plate 12 is formed with a tooth profile 12a having the same pitch as the roller 11.
a engages with the rail 10 while contacting the surface of the roller 11 (the first roller 11a or the first roller 11b).

Reference numerals 12c and 12d denote circular holes, and these circular holes 12c and 12d have eccentric crankshafts (not shown) (the first eccentric crankshafts 7a to 7c and the second eccentric crankshaft 7a to 7c of the linear motion mechanism according to the prior application). Eccentric crankshaft 8
a to 8c) are rotatably engaged. In such a configuration, when an eccentric crankshaft (not shown) rotates, three rotating plates including the rotating plate 12 shown in the drawing make a circular motion while maintaining a phase difference of 120 degrees, and the tooth profile of each rotating plate (typically 12a) Moves sequentially while being engaged with the rollers 11 of the rails 10 for each rotating plate.

Here, the diameter of the second roller 11b is the first roller 11b.
Is slightly larger than the diameter of the roller 11a, and the rigidity of the second roller 11b is lower than that of the first roller 11a. Pressurization determined by force is applied. Therefore, the fluctuation of the contact pressure during the movement is absorbed by the above-mentioned pressurization (elastic force) and is always maintained at an appropriate level, so that there is no practical decrease in efficiency and no increase in backlash. Linear motion mechanism can be provided.

The present embodiment is an example of application to a device in which a roller is mounted on a rail. However, the present invention is not limited to this, and a device in which a roller is mounted on a rotating plate side (for example, a linear motion mechanism according to the prior application) Of course, it can be applied to 2 and 3 are diagrams showing examples of a contact pressure adjusting mechanism at rest. In FIG. 2, a case 13 containing a mechanical part such as a rotating plate 12 is mounted on a gantry 1 via a shim 14.
5, and the gantry 15 is slidably engaged with a guide groove 10 a formed on the side surface of the rail 10. In this example, the contact pressure at rest is adjusted by changing the thickness of the shim 14, but there is a problem that various types of shims are required for each thickness.

The example of FIG. 3 can solve such a problem. In the example of FIG. 3A, the lower surface of the case 13a is inclined, and a wedge-shaped cross section is provided between the case 13a and the gantry 15a. The shim 16 is sandwiched, and the horizontal position of the shim 16 is changed by the adjusting screw 17 to adjust the contact pressure at rest. In the example of FIG. 3B, two shims 18 a and 18 b having a wedge-shaped cross section are sandwiched between the case 13 b and the gantry 15 b, and the horizontal position of one of the shims 18 b is changed by the adjusting screw 19 to stand still. The contact pressure is adjusted. In both cases,
The contact pressure can be adjusted in accordance with the inclination angles of the shims 16, 18a, 18b having a wedge-shaped cross section, and it is not necessary to prepare an extra shim. .

[0020]

According to the present invention, since a plurality of rollers include an elastically deformable roller, the contact pressure during exercise can always be appropriately maintained by the elastic force, and the efficiency is reduced. A practical linear motion mechanism that does not cause an increase in backlash can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment and an external view of a second roller.

FIG. 2 is a diagram illustrating an adjustment mechanism of a contact pressure at the time of rest.

FIG. 3 is a view showing an improved adjustment mechanism of a contact pressure at the time of rest.

FIG. 4 is a conceptual configuration diagram of a linear motion mechanism according to the prior application.

FIG. 5 is an explanatory diagram of an operation of the linear motion mechanism according to the prior application.

[Explanation of symbols]

K _ia ~K _id: sliding body 1: Input shaft 2～4,12: rotating plate 10: rail 11: roller 11a: first roller 11b: second roller

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomohiro Kiriyama 1110-1 Ozaki, Miyashiro, Tarui-cho, Fuwa-gun, Gifu Prefecture Teijin Seiki Co., Ltd. 1110-1 Ozaki, Machimiyashiro Teijin Machinery Co., Ltd. Gifu Daiichi Plant (56) References JP-A-4-210514 (JP, A) JP-A-1-65973 (JP, U) JP-A-3-102507 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 19/04 F16H 25/08 B65G 39/00-39/20

Claims (2)

(57) [Scope of request for utility model registration] 1. A rail in which a number of rollers are arranged at a predetermined pitch, and at least three sets of sliding bodies that slide or roll on the rails as a set of at least two rollers arranged in the sliding direction at the same pitch as the rollers. A plurality of rotating plates that rotate in synchronization with the rotation of the input shaft, the number of the rotating plates is the same as the number of sets of the sliding body, and the rotating shaft of each rotating plate in the direction orthogonal to the rail. A linear motion mechanism having an axis and a predetermined phase difference in the rotational motion between the rotary plates, and further including a set of the sliding bodies attached to each rotary plate; A first roller having a diameter and a high rigidity; and a second roller having a diameter larger than the diameter of the first roller and having a low rigidity, wherein the second rollers are arranged at regular intervals. You Linear motion mechanism. 2. The linear motion mechanism according to claim 1, wherein a sliding body is provided on the rail, and a first roller and a second roller are provided on the rotating plate.