JP2013145033A - Linear motion bearing and linear motion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motion bearing which does not cause problems during the use as a linear motion bearing despite of a constitution having a small ratio of the size (outer diameter) of an outer cylinder to the size (diameter) of a shaft to be inserted.SOLUTION: The linear motion bearing includes: an outer cylinder 11; a cylindrical ball retainer 12 fitted in the inside of the outer cylinder; a plurality of balls 13 retained in a cylindrical ball retainer. Here, the cylindrical ball retainer includes a plural lines of loop shaped grooves 15 for circulation of balls, which extends in an axial direction and stores at least two balls in a state partly protruded interposing a slit 14 formed in the axial direction on the inner peripheral side of the retainer. The linear motion bearing works for a linear motion of a shaft 21 having a diameter of 3-9 mm. The diameter dof the shaft, the diameter dof the ball, the outer diameter dof the outer cylinder and the thickness t of the outer cylinder hold following relationships: (1) 1.4<d/d<1.8; (2) 0.1<d/d<0.2; and (3) 0.1<t/d<0.2.

Description

  The present invention relates to a linear motion bearing and a linear motion device that can be used particularly advantageously to support a shaft that performs linear motion in the vertical direction.

  2. Description of the Related Art Conventionally, linear motion bearings (linear bearings) are generally used to support shaft bodies that are linearly driven in various mechanical devices.

  The linear motion bearing is usually composed of an outer cylinder, a cylindrical sphere holder (spherical bearing holder) fitted inside the outer cylinder, and a plurality of spheres held by the cylindrical sphere holder. The linearly moving shaft is inserted inside the cylindrical sphere holder and is supported by a plurality of rotating spheres partially protruding inside the cylindrical sphere holder, thereby enabling smooth sliding.

  Depending on the arrangement of the shaft body to be inserted, the linear motion bearing may be used to linearly move the shaft body arranged in the vertical direction in the length direction (vertical direction) or arranged in the horizontal direction. It may be used to move the shaft body linearly in the length direction (lateral direction).

  Among linear motion bearings, spherical infinite circulation type linear motion bearings, in which a spherical circulation groove is formed in a cylindrical spherical cage to enable infinite circulation of a plurality of spherical bodies, have no limitation on the travel distance of the shaft body. Therefore, it is used for a wide range of applications.

  For example, as disclosed in Patent Document 1, the above-mentioned spherical infinite circulation type linear motion bearing is generally provided with an outer cylinder, a cylindrical sphere holder fitted inside the outer cylinder, and a cylindrical sphere holder. The cylindrical sphere holder has a configuration in which two or more spheres are partially protruded through a slit formed along the axial direction on the inner peripheral side of the cylindrical sphere holder. A plurality of loop-shaped spherical circulation grooves extending in the axial direction and housed in a state are provided.

  As described above, spherical infinite circulation type linear motion bearings are used in a wide range of applications. In recent years, it has been required to reduce the diameter of the outer cylinder of the linear motion bearing. That is, for example, an apparatus such as an arrangement unit for minute parts such as electronic parts described in Patent Document 2 temporarily holds minute parts arranged in a tray with a shaft inserted in a linear motion bearing. Then, it is arranged at a desired position. Such an arrangement unit for electronic components is used by being incorporated in an electronic component mounting apparatus, and various types are known depending on the configuration of the mounting apparatus. With respect to such an arrangement unit, it is required to further reduce the size of the electronic component in accordance with the recent miniaturization of the electronic component, and also to reduce the weight. However, in consideration of the intended application, it is difficult to change the diameter of the shaft body. Therefore, the reduction in size and weight reduction are based on the condition that a conventionally used shaft body can be used as it is.

  In consideration of the above requirements, a possible means for reducing the size and weight of the micropart placement unit is to reduce the size of the outer cylinder of the linear motion bearing. Since the diameter of the tube cannot be changed, it is inevitably necessary to reduce the thickness of the outer cylinder. However, if the thickness of the outer cylinder is reduced, the mechanical strength of the linear motion bearing is lowered, and there arises a problem that sufficient mechanical strength required for supporting the shaft body cannot be obtained. In addition, as a means for reducing the size of the linear motion bearing and reducing the weight, the size of the sphere that is interposed between the outer cylinder and the shaft body and can be rotated for smooth sliding of the shaft body is used. It is conceivable to reduce the size. However, even when the size of the sphere is reduced, there is a problem that the mechanical strength (load resistance) of the linear motion bearing is lowered and sufficient mechanical strength required for supporting the shaft body cannot be obtained. Occur. Such a decrease in mechanical strength is particularly noticeable in the case of a linear motion bearing using a thin shaft body having a diameter of 3 to 9 mm, which cannot originally use a sufficiently thick outer cylinder.

Japanese Patent Laying-Open No. 2005-83565 JP 2011-228592 A

  The present invention is a linear motion bearing of the same type as a conventionally used spherical infinite circulation type linear motion bearing, and the ratio of the size (outer diameter) of the outer cylinder to the size (diameter) of the inserted shaft body is An object of the present invention is to provide a linear motion bearing and a linear motion device that are configured to be small, but do not cause problems in use as a linear motion bearing.

  In order to solve the above-mentioned problems, the present inventor studied the configuration and usage of a spherical infinite circulation type linear motion bearing. As a result, the thickness of the outer cylinder of the linear motion bearing is reduced so as to be within a certain range as a ratio to the diameter of the shaft, and the size (diameter) of the sphere accommodated and held in the cylindrical sphere holder is also the same. When the shaft body is made small so that the ratio to the diameter of the shaft body is within a certain range, and this is used as a linear motion bearing that requires linear motion in the vertical direction (vertical direction) of the shaft body, On the other hand, since a large load is not applied in the diameter direction, it has been found that there is no practical problem, and the present invention has been achieved.

  Therefore, the linear motion bearing of the present invention shows high practicality particularly when used as a linear motion bearing that requires linear motion in the vertical direction (longitudinal direction) of the shaft body. When the load applied in the direction (width direction) is not large, the shaft body can be used as a linear motion bearing for linear motion in the horizontal direction (lateral direction).

The present invention includes an outer cylinder, a cylindrical sphere holder fitted inside the outer cylinder, and a plurality of spheres held by the cylindrical sphere holder, provided that the cylindrical sphere holder includes Provided with a plurality of axially extending loop-shaped sphere circulation grooves that accommodate two or more spheres partially protruding through slits formed along the axial direction on the circumferential side A linear motion bearing for linear motion of a shaft body having a diameter of 3 to 9 mm, the shaft body diameter d ₀ , the spherical body diameter d ₁ , the outer cylinder outer diameter d ₂ , and the outer cylinder thickness t Satisfies the relationship of the following formulas (1) to (3).
(1) 1.4 <d ₂ / d ₀ <1.8
(2) 0.1 <d ₁ / d ₀ <0.2
(3) 0.1 <t / d ₀ <0.2

Preferred embodiments of the linear motion bearing of the present invention are as follows.
(I) Used for linear motion in the vertical direction of the shaft
(II) Used for linear movement of a shaft having a diameter of 3 to 5 mm.

The present invention also includes an outer cylinder, a cylindrical sphere holder fitted inside the outer cylinder, and a plurality of spheres held by the cylindrical sphere holder, provided that the cylindrical sphere holder is Provided with a plurality of axially extending loop-shaped sphere circulation grooves that accommodate two or more spheres partially protruding through slits formed along the axial direction on the inner peripheral side A linear motion device in which the shaft body is arranged in a vertical direction, the linear motion device including a shaft body having a diameter of 3 to 9 mm inserted in the linear motion bearing, wherein the shaft body has a diameter d ₀ , There is also a linear motion device characterized in that the diameter d _{1 of} the sphere, the outer diameter d _{2 of} the outer cylinder, and the thickness t of the outer cylinder satisfy the following expressions (1) to (3).
(1) 1.4 <d ₂ / d ₀ <1.8
(2) 0.1 <d ₁ / d ₀ <0.2
(3) 0.1 <t / d ₀ <0.2

In the present specification, the “diameter of the shaft body” means the diameter of the shaft body when the linear motion bearing accommodates the shaft body. In addition, when the linear motion bearing does not accommodate the shaft body, but the diameter of the shaft body to be accommodated is predetermined, it means the diameter of the predetermined shaft body. When neither of the above cases applies, it means the diameter d ₀ of the shaft obtained by calculation from the following equation (4).
(4) d ₀ = d ₂ −2 × (d ₁ + t)

  In the present specification, the “outer diameter of the outer cylinder” refers to the center of the outer cylinder and the cylindrical sphere holder when the outer diameter of the outer cylinder varies in the circumferential direction of the outer cylinder. This means the diameter of the outer cylinder on a straight line passing through the center of the sphere that is received in the spherical circulation groove and reaches the slit. Also, the “outer cylinder thickness” means that when the thickness of the outer cylinder fluctuates in the circumferential direction of the outer cylinder, the outer cylinder is accommodated in the center and the spherical circulation groove of the cylindrical sphere cage. It means the thickness of the outer cylinder on a straight line passing through the center of the reached sphere.

  The linear motion bearing and linear motion device according to the present invention are configured so that the ratio of the size (outer diameter) of the outer cylinder to the size (diameter) of the shaft body inserted into the linear motion bearing is reduced. And lighter weight. And when the force (load) applied to the diameter direction (width direction) of the shaft body of the linear motion bearing is not large, for example, when used for the linear motion of the shaft body arranged in the vertical direction, or arranged in the horizontal direction When the shaft body is used for linear motion and the load applied in the diameter direction of the shaft body is not large, there is no practical problem in use as a linear motion bearing.

It is sectional drawing which shows the structural example of the linear motion apparatus containing the linear motion bearing of this invention. However, the sphere 13 is not shown as a cross section. Also, a sphere that is further above the sphere 13 written at the upper end and a sphere that is further lower than the sphere 13 written at the lower end are not shown. It is sectional drawing of the linear motion apparatus 20 cut | disconnected along the cutting line II-II line entered in FIG. However, each sphere 13 is not shown as a cross section.

  A typical embodiment of a linear motion device including the linear motion bearing of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a configuration example of a linear motion device including the linear motion bearing of the present invention. 2 is a cross-sectional view of the linear motion device 20 cut along the cutting line II-II entered in FIG. However, the sphere 13 is not shown as a cross section in each figure. Further, in FIG. 1, a sphere further above the sphere 13 written at the upper end and a sphere further below the sphere 13 written at the lower end are not shown.

  A linear motion bearing 10 shown in FIGS. 1 and 2 includes an outer cylinder 11, a cylindrical sphere holder 12 fitted inside the outer cylinder 11, and a plurality of spheres 13 held by the cylindrical sphere holder 12. It has.

  The cylindrical sphere holder 12 includes a plurality of (four in total) sphere circulation grooves 15. Each spherical circulation groove 15 has a loop shape extending in the axial direction (the length direction of the cylindrical spherical cage).

  The sphere circulation groove 15 is formed on the outer peripheral surface of the cylindrical sphere holder 12 and includes linear grooves 15a and 15b and connection grooves 15c and 15d. The connecting groove 15c connects the linear grooves 15a and 15b to each other at the upper end in FIG. The straight groove 15d connects the straight grooves 15a and 15b to each other at the lower end in FIG. A slit 14 described later is provided at the bottom of the linear groove 15a.

  A slit 14 is formed along the axial direction on the inner peripheral side of the cylindrical sphere holder 12. Each sphere circulation groove 15 has two or more spheres (for example, nine spheres protruding from the slits 14 of each sphere circulation groove 15 shown in FIG. 1) 13 in a cylindrical shape through the slits 14. The spherical holder 12 is housed in a state of protruding to the inner peripheral side.

  Retaining rings (snap rings) 16 and 16 are disposed on both outer sides in the axial direction of the cylindrical sphere holder 12 so that the cylindrical sphere holder 12 does not jump out of the outer cylinder 11. A portion on the outer peripheral side of each retaining ring 16 is fitted in an annular groove formed on the inner peripheral surface of the outer cylinder 11.

  The linear motion bearing 10 is used for linear motion (particularly preferably linear motion in the vertical direction) of a shaft body 21 having a diameter of 4 mm. The linear motion device 10 of the present invention is configured by the linear motion bearing 10 and the shaft body 21 that is inserted into the linear motion bearing 10 and arranged in the vertical direction.

  The outer diameter of the outer cylinder 11 of the linear motion bearing 10 is set to 6.5 mm, the thickness of the outer cylinder 11 is set to 0.55 mm, and the diameter of the spherical body 13 is set to 0.7 mm.

That is, in the linear bearing 10, the ratio (d ₂ / d ₀ ) of the diameter (outer diameter) of the outer cylinder of the linear bearing to the diameter of the shaft body is 1.625, and the diameter of the sphere with respect to the diameter of the shaft body is 1. The ratio (d ₁ / d ₀ ) is set to 0.175, and the ratio of the thickness of the outer cylinder to the shaft body diameter (t / d ₀ ) is set to 0.138.

Thus, the linear motion bearing 10 (or linear motion device 20) has a shaft body diameter d ₀ , a sphere diameter d ₁ , an outer cylinder outer diameter d ₂ , and an outer cylinder thickness t having the following formula ( It is characterized by satisfying the relationships 1) to (3).
(1) 1.4 <d ₂ / d ₀ <1.8
(2) 0.1 <d ₁ / d ₀ <0.2
(3) 0.1 <t / d ₀ <0.2

As described above, in the linear motion bearing 10, the ratio (d ₂ / d ₀ ) of the outer diameter d ₂ of the outer cylinder 11 to the diameter d ₀ of the shaft body 21 is constant for the purpose of reducing the size and weight. The value is set to a small value (1.625) so as to be in the range (the range satisfying the relationship of the above formula (1)). That is, an extremely small outer cylinder having an outer diameter of 6.5 mm is used for the shaft body 21 having a diameter of 4 mm inserted into the linear motion bearing 10.

In the linear motion bearing 10, the thickness t of the outer cylinder 11 is further in a certain range (range satisfying the relationship of the above expression (3)) as a ratio (t / d ₀ ) to the diameter d ₀ of the shaft body 21. The diameter d _{1 of the} sphere 13 accommodated and held in the cylindrical sphere holder 12 is similarly set within a certain range as the ratio (d ₁ / d ₀ ) to the diameter d ₀ of the shaft body (the above formula (2 ) To be within the range that satisfies the relationship (1).

  Thus, in order to reduce the size and reduce the weight of the linear motion bearing 10, both the thickness of the outer cylinder 11 and the diameter of the sphere 13 are in a certain range as a ratio to the diameter of the shaft body. By reducing the size, the load applied in the diameter direction of the shaft body 21 is not large. In particular, when the shaft body is arranged in the vertical direction, a practical problem is not generated.

  Even if the thickness of the outer cylinder of the linear motion bearing is only made smaller than the diameter of the shaft body, it is possible to reduce the size and weight of the linear motion bearing to some extent. However, when the thickness of the outer cylinder is gradually reduced with respect to the diameter of the shaft body in order to realize a sufficient reduction in size and weight, the mechanical strength of the linear motion bearing is reduced, and the shaft body is There arises a problem that sufficient mechanical strength required for supporting cannot be obtained. Further, there arises a problem that the outer cylinder is likely to be deformed or damaged during manufacture or subsequent handling.

  Further, even if the diameter of the sphere of the linear motion bearing is simply made smaller than the diameter of the shaft body, it is possible to reduce the size and weight of the linear motion bearing to some extent. However, when the diameter of the sphere is gradually reduced with respect to the diameter of the shaft body in order to realize a sufficient size reduction and weight reduction, the mechanical strength of the linear motion bearing, more specifically, There arises a problem that the load resistance in the diameter direction of the shaft body is lowered.

  In order to solve these problems, the inventors of the present invention have studied the configuration and usage of a spherical infinite circulation type linear motion bearing as described above. As a result, in order to reduce the size and weight of the linear bearing, not only one of the thickness of the outer cylinder and the diameter of the sphere, but both of them are in a certain range as a ratio to the diameter of the shaft. When this is used as a linear motion bearing that requires linear motion in the vertical direction (vertical direction) of the shaft body, a large load is applied to the shaft body in the diameter direction. Therefore, it has been found that there is no problem in practical use (a decrease in mechanical strength as described above is not a problem).

  That is, when the linear motion bearing is used as a linear motion bearing that requires linear motion in the vertical direction (vertical direction) of the shaft body as described above, a large load is applied to the shaft body in the diameter direction. There is no. For this reason, the diameter of the sphere can be reduced as a ratio to the diameter of the shaft body within a range that does not cause a problem in the mechanical strength (load resistance) of the linear motion bearing.

  Therefore, in order to reduce the size and weight of the linear motion bearing, when reducing the diameter of the outer cylinder as a ratio to the diameter of the shaft body, the diameter of the sphere is not reduced as a ratio to the diameter of the shaft body. The thickness of the outer cylinder can be increased. For this reason, it becomes possible to obtain a mechanical strength of the outer cylinder that is practically sufficient.

  As described above, the linear motion bearing of the present invention reduces both the thickness of the outer cylinder and the diameter of the sphere in a well-balanced manner in consideration of the usage of the linear motion bearing (the ratio of each to the diameter of the shaft body). As a result, the size can be significantly reduced and the weight can be reduced.

  Below, the structure and preferable embodiment of the linear motion bearing and linear motion apparatus of this invention are demonstrated in detail.

As described above, the linear motion bearing of the present invention includes an outer cylinder, a cylindrical sphere holder fitted inside the outer cylinder, and a plurality of spheres held by the cylindrical sphere holder, The cylindrical sphere retainer is an axially extending loop-shaped housing that accommodates two or more spheres partially protruding through slits formed along the axial direction on the inner peripheral side thereof. A linear motion bearing for linear motion of a shaft body having a diameter of 3 to 9 mm, provided with a plurality of spherical circulation grooves, the shaft body diameter d ₀ , the sphere diameter d ₁ , and the outer diameter of the outer cylinder It is characterized in that d ₂ and the thickness t of the outer cylinder satisfy the following expressions (1) to (3).
(1) 1.4 <d ₂ / d ₀ <1.8
(2) 0.1 <d ₁ / d ₀ <0.2
(3) 0.1 <t / d ₀ <0.2

  The linear motion bearing of the present invention is reduced in size and weight by using a thin shaft body with a diameter of 3 to 9 mm (especially 3 to 5 mm), which cannot originally use a sufficiently thick outer cylinder. Useful for.

In order to further reduce the size and weight of the linear bearing, the shaft diameter d ₀ , sphere diameter d ₁ , outer cylinder outer diameter d ₂ , and outer cylinder thickness (thickness) t are further increased. It is preferable to satisfy the relationship of the following formulas (5) to (7).
(5) 1.4 <d ₂ / d ₀ <1.72
(6) 0.1 <d ₁ / d ₀ <0.18
(7) 0.1 <t / d ₀ <0.18

As described above, in the linear motion bearing 10 shown in FIGS. 1 and 2, the ratio (d ₂ / d ₀ ) of the outer diameter of the linear motion bearing outer cylinder to the diameter of the shaft body is 1.625, The ratio of the diameter of the sphere to the diameter of the body (d ₁ / d ₀ ) is set to 0.175, and the ratio of the thickness of the outer cylinder to the diameter of the shaft (t / d ₀ ) is set to 0.138. Therefore, it is configured so as to satisfy the relations (5) to (7).

  The linear motion bearing 10 is used for linear motion (particularly preferably linear motion in the vertical direction) of a thin shaft body having a diameter of 4 mm. As described above, the outer diameter is extremely small such as 6.5 mm. The outer cylinder 11 is used to achieve a significant reduction in size and weight. Specifically, the circular movement of a sphere having a diameter of 0.7 mm is realized inside a cylindrical region having a thickness of 1.25 mm between the outer peripheral surface of the shaft body 21 and the outer peripheral surface of the outer cylinder 11. Yes.

  The material of the outer cylinder is usually formed from a metal material typified by steel (eg, stainless steel).

  The length of the outer cylinder is usually set to a length within the range of 1 to 5 times (preferably 1 to 4 times) the diameter of the shaft body in order to reduce the axial size of the linear motion bearing.

  The cylindrical sphere holder is made of, for example, a metal material or a resin material. Examples of the resin material include polyacetal resin, polyphenylene sulfide (PPS) resin, polyamide resin, and polyether ether ketone (PEEK) resin.

  A plurality of sphere circulation grooves are provided on the outer peripheral surface of the cylindrical sphere cage. The number of spherical circulation grooves is preferably in the range of 3-5.

  As described above, in the linear motion bearing of the present invention, since the diameter of the sphere is reduced as a ratio to the diameter of the shaft, the thickness of the sphere holder that accommodates and holds the sphere is reduced accordingly. For this reason, when a large number of spherical circulation grooves are formed in the cylindrical sphere holder, the mechanical strength of the cylindrical sphere holder is reduced, and the cylindrical sphere holder is deformed or damaged during manufacture or subsequent handling. It becomes easy. Therefore, in the linear motion bearing of the present invention used for the linear motion of a thin shaft body having a diameter of 3 to 9 mm (particularly 3 to 5 mm) in which a cylindrical sphere cage having such a sufficient thickness cannot be used, As described above, it is particularly preferable to set the number of sphere circulation grooves provided in the cylindrical sphere holder in the range of 3 to 5.

  The number of spheres protruding from the slits provided in the cylindrical cage is preferably in the range of 2 to 15 so that the linear motion bearing exhibits sufficient load resistance, and 3 to 12 More preferably, it is in the range, and particularly preferably in the range of 3-10.

  The sphere is usually formed from a metal material typified by steel (eg, stainless steel). The retaining ring 16 is made of, for example, a metal material or a resin material.

  As a shaft inserted into the linear motion bearing of the present invention, for example, a shaft made of a metal material typified by steel can be used.

  As the shaft body, a shaft body provided with a plurality of linear grooves extending in the axial direction (grooves that engage with the sphere of the linear motion bearing) on the peripheral surface, or does not have the above-described linear grooves, and thus has a circular cross section. A shaft can be used. When a shaft body having a straight groove is used, it is necessary to project the sphere greatly toward the inner peripheral side of the cylindrical sphere cage so that the sphere of the linear motion bearing engages with the linear groove of the shaft body. On the other hand, when a shaft body having a circular cross section is used, it is easy to increase the thickness of the cylindrical sphere cage as a ratio to the diameter of the shaft body, compared to the case of using a shaft body having a linear groove as described above. . For this reason, it is easy to obtain sufficient mechanical strength of the cylindrical sphere cage. Therefore, the linear motion bearing of the present invention is particularly preferably used for linear motion of a shaft having a circular cross section.

  A hollow shaft body can also be used as the shaft body. The linear motion bearing of the present invention in which a hollow shaft body is inserted, that is, the linear motion device of the present invention can be particularly preferably used for an arrangement unit for minute parts such as electronic parts.

  By attaching a suction nozzle for minute parts to the lower end of the hollow shaft body, connecting the opening at the upper end to a decompression device, and decompressing the interior of the shaft body by the decompression device, the minute parts are attracted to the suction nozzle. Is possible.

DESCRIPTION OF SYMBOLS 10 Linear motion bearing 11 Outer cylinder 12 Cylindrical spherical holder 13 Sphere 14 Slit 15 Sphere circulation groove 16 Retaining ring 20 Linear motion device 21 Shaft body d ₀ Shaft diameter d ₁ Diameter of spherical body d ₂ Outer diameter of outer cylinder t Thickness of outer cylinder

Claims (4)

An outer cylinder, a cylindrical sphere holder fitted inside the outer cylinder, and a plurality of spheres held by the cylindrical sphere holder, provided that the cylindrical sphere holder has an inner peripheral side A plurality of axially extending loop-shaped sphere circulation grooves are housed in a state in which two or more spheres are partially protruded through a slit formed along the axial direction. A linear motion bearing for linear motion of a shaft body having a diameter of 3 to 9 mm, wherein the shaft body diameter d ₀ , the sphere diameter d ₁ , the outer cylinder outer diameter d ₂ , and the outer cylinder thickness t are as follows: connection of:
(1) 1.4 <d ₂ / d ₀ <1.8
(2) 0.1 <d ₁ / d ₀ <0.2
(3) 0.1 <t / d ₀ <0.2
Linear motion bearings characterized in that.   The linear motion bearing according to claim 1, which is used for linear motion in a vertical direction of the shaft body.   The linear motion bearing according to claim 1 for linear motion of a shaft body having a diameter of 3 to 5 mm. An outer cylinder, a cylindrical sphere holder fitted inside the outer cylinder, and a plurality of spheres held by the cylindrical sphere holder, provided that the cylindrical sphere holder has an inner peripheral side A plurality of axially extending loop-shaped sphere circulation grooves that accommodate two or more spheres partially protruding through slits formed along the axial direction. A linear motion device in which a shaft body is arranged in a vertical direction, including a dynamic bearing and a shaft body having a diameter of 3 to 9 mm inserted in the linear motion bearing, wherein the shaft body has a diameter d ₀ , The diameter d ₁ , the outer diameter d _{2 of} the outer cylinder, and the thickness t of the outer cylinder have the following relationship:
(1) 1.4 <d ₂ / d ₀ <1.8
(2) 0.1 <d ₁ / d ₀ <0.2
(3) 0.1 <t / d ₀ <0.2
A linear motion device characterized by that.

Images