JP4527964B2 - Tension pulley and rotation transmission mechanism - Google Patents

Description

  The present invention relates to a rotation transmission mechanism in which a steel belt is stretched between an input side pulley and an output side pulley and the output side pulley is rotated following the rotation of the input side pulley, and in particular, the tension of the belt is adjusted. It relates to the improvement of the tension pulley.

  A conventional rotation transmission mechanism including a tension pulley will be described with reference to FIGS. FIG. 5A is a conceptual diagram of the rotation transmission mechanism as viewed from above, and FIG. 5B is a conceptual diagram as viewed from the front. 4 (a) and 4 (b) illustrate a state in which the steel belt is in contact with the tension pulley in a cross-section in a plane including the axis of the tension pulley.

  In the conventional rotation transmission mechanism 50, the input side pulley 3 is attached to the output shaft 2 a of the power source 2 fixed to the base 1, and the output side pulley 4 is further attached to the base 1. A load 5 to be finally driven by gripping the workpiece is attached.

  A steel belt 6 is stretched between the input pulley 3 and the output pulley 4 so as to obtain a rotational output corresponding to the pulley ratio.

  A tension pulley 7 for adjusting the tension of the steel belt 6 is also provided.

  The operation of the rotation transmission mechanism 50 configured as described above will be described. When the output shaft 2a of the power source 2 rotates, the input pulley 3 rotates at the same rotational speed as the output shaft 2a. The output pulley 4 rotates at a rotation ratio of (input pulley 3) / (output pulley 4) via the belt 6. As a result, the load 5 that is the final load attached to the output pulley 4 also rotates at the same rotational speed as the output pulley 4.

  Here, the tension pulley 7 has the role of adjusting the tension of the steel belt 6 to prevent loosening and improving the rotation efficiency. However, the conventional tension pulley 7 is normally used as shown in FIG. Is equipped with a cylindrical roller bearing.

  The structure of this conventional tension pulley 7 will be described in detail with reference to FIG.

  The tension pulley 7 of the conventional system includes an outer ring 8 that rotates on an outer peripheral surface of the steel belt 6 that is driven between the input-side pulley 3 and the output-side pulley 4, and a smooth rotational movement of the outer ring 8. And a cylindrical roller 10 that places importance on the radial load, a roller receiver 12 that serves as a guide for the cylindrical roller 10, an inner shaft 11 that serves as a fixed shaft for the pulley, and an outer peripheral surface that is mounted on the inner shaft 11 and has a cylindrical roller 10 And an inner ring 9 serving as a contact surface.

The tension pulley 7 is adjusted to a position where the outer ring 8 is appropriately in contact with the steel belt 6 to suppress the loosening of the steel belt 6 when the steel belt 6 is driven, to improve the driving efficiency and to give the friction to the steel belt 6. The structure is minimized.
Japanese Utility Model Publication No. 5-71551

In the tension pulley 7, the contact surface of the outer ring 8 and the contact surface of the steel belt 6 may come into contact with each other at different angles as shown in FIG. In this way, when the steel belt 6 is unevenly contacted, the steel belt 6 is subjected to excessive stress locally. However, in the conventional rotation transmission mechanism 50, a cylindrical roller bearing used for the tension pulley 7 is provided. Since it is made of a hard material such as stainless steel, the steel belt having a lower strength than the outer ring 8 is more susceptible to damage.

  Further, even when a sudden tension fluctuation input from the load side occurs, the tension fluctuation has a structure in which the steel belt having the weakest strength absorbs the impact.

  As a result, the steel belt is excessively stressed, easily damaged and broken, and the life of the steel belt is greatly shortened. The short life of the steel belt 6 has led to a decrease in the reliability of the entire rotation transmission mechanism and a shortened maintenance cycle. According to the data of the experiment conducted by the applicant, in the case of the conventional rotation transmission mechanism in which the cylindrical roller bearing as shown in FIG. 4 is formed of a hard material such as stainless steel, the level is less than 30,000 operations. In some cases, the steel belt 6 may be modulated or damaged.

In the present invention, a shock-absorbing member such as an O-ring is provided between an inner shaft of a tension pulley and an outer ring rotatably mounted on the tension pulley, and is generated from the uneven contact of the steel belt or the load side. When a sudden tension change occurs, the buffer member is deformed, so that in the case of a conventional tension pulley, if the steel belt is unevenly contacted, the outer ring outer peripheral surface that comes into contact with the contact surface of the steel belt The problem is solved by automatically adjusting the inclination angle with respect to the inner shaft and allowing the position of the outer ring to be displaced with respect to the inner shaft when sudden tension fluctuations occur.

That is, the tension pulley proposed in this invention, the endless belt is stretched between the input pulley and the output pulley of the rotation transmission mechanism for rotating the output-side pulley in accordance with the rotation of the input side pulley A tension pulley that adjusts the tension ,
An inner shaft, a cylindrical body, a collar portion mounted on the inner shaft, a cylindrical body, an outer ring whose outer peripheral surface is in contact with an endless belt, and a bearing interposed between the collar portion and the outer ring. And an O-ring interposed between the inner shaft and the collar portion, and the collar portion is located on the outer side than both edges in the axial direction of the interposed portion where the bearing is disposed, and the interposed portion. Each having an accommodating portion in which an O-ring is disposed, and the inner wall surface of the accommodating portion is outside the inner wall surface of the interposition portion in the radial positional relationship of the collar portion. Is.

  The inner shaft is a fixed shaft that becomes the center of rotation of the tension pulley, and is attached to a rotation transmission mechanism, for example, an arm of a substrate transport robot.

  The endless belt is an annular belt that does not have an end in the moving (rotating) direction of the belt, and there are steel and rubber ones. This steel belt will be explained.

The buffer member can be interposed between the inner shaft and the outer ring on the sides corresponding to the opposite side edges of the steel belt, that is, on the distal end side and the proximal end side of the inner shaft. The uneven contact of the steel belt is often caused by a shift in the angle between the outer peripheral surface of the outer ring and the contact surface of the steel belt. Therefore, if the buffer members are respectively provided at the distal end side and the proximal end side of the inner shaft, the buffer members on the distal end side and the proximal end side are deformed according to the input to the outer peripheral surface of the outer ring , and the outer ring It is possible to cope with an angle shift between the outer peripheral surface of the steel plate and the contact surface of the steel belt. If the buffer member is interposed in this way, the buffer member is deformed between the inner shaft and the outer ring. Therefore, the inclination angle of the outer peripheral surface of the outer ring that contacts the contact surface of the steel belt with respect to the inner shaft is set to the contact surface of the steel belt. It becomes possible to automatically adjust according to the angle. Further, the outer ring can be moved away from the inner shaft in response to an input from the outside. Thereby, it is possible to prevent the endless steel belt from being unevenly contacted, and to cope with sudden tension fluctuations.

  That is, when the steel belt is unevenly contacted or sudden tension fluctuation occurs from the load side, the buffer member can be deformed following the fluctuation to reduce the load on the steel belt. .

When the steel belt comes into contact with the shock absorber due to assembly tolerances , the shock absorber can tilt the outer ring with respect to the inner shaft according to the angle of the steel belt contact surface, and sudden tension fluctuations generated from the load side can occur. Any material and shape can be adopted as long as they can be deformed following the displacement of the outer ring corresponding to the inner shaft when it occurs. For example, a rubber material or a metal hollow O-ring can be employed.

  The tension pulley described above is a rotation transmission mechanism that has been widely used in the past, and is a type in which an endless belt is stretched between an input pulley and an output pulley to transmit rotational force. Anything can be worn and used.

  As described above, according to the present invention, a buffer member such as an O-ring is interposed between the outer shaft and the inner shaft of the tension pulley, for example, on the distal end side and the proximal end side of the inner shaft. It is possible to prevent the uneven contact of the steel belt with the belt. In addition, it is possible to cope with sudden input. As a result, it is possible to cope with uneven contact of the steel belt and sudden tension fluctuations generated from the load side, and it is possible to achieve a long life of the steel belt.

  Moreover, the reliability of the rotation transmission mechanism itself can be improved by using this tension pulley.

  Furthermore, the time required for tension adjustment can be shortened by increasing the tension adjustment margin of the steel belt.

  Embodiments of the present invention will be described below. 1 (a) and 1 (b) show a state in which the steel belt is in contact with the tension pulley in a cross-section along the plane including the axis of the tension pulley, as in FIGS. 4 (a) and 4 (b) illustrating the conventional example. Is described.

The tension pulley 16 of the present invention is one in which an outer ring 18 is rotatably attached to the inner shaft 11. In the illustrated example, the rotatable attachment of the outer ring 18 to the inner shaft 11 is the inner shaft 1.
1, a collar portion 14 made of a cylindrical body is attached, and an outer shaft 17 is attached to the outer periphery of the collar portion 14 via a bearing 15. The collar portion 14 plays a role of holding the O-rings 13a and 13b, and a bearing 19 is interposed between the collar portion 14 and the outer ring 18 to form a rotating structure.

  On the upper and lower edge portions of the collar portion 14, housing portions 14a for O-rings 13a and 13b are formed, respectively. The O-ring 13 a is attached to the accommodating portion 14 a located on the distal end side of the inner shaft 11, and the O-ring 13 b is attached to the accommodating portion 14 a located on the proximal end side of the inner shaft 11.

In addition, the outer peripheral surface of the outer ring 18 comes into contact with the steel belt 6 stretched between the output side pulley and the input side pulley.

  Similar to the conventional method, the tension pulley 16 prevents the steel belt 6 from loosening and operates so that the frictional force applied to the steel belt 6 is minimized when the steel belt 6 rotates in the rotational direction. Adjustment is made so that a load is always applied to the steel belt 6 in order to improve the rotation efficiency.

  The tension pulley 16 configured in this manner is used by being attached to a rotation transmission mechanism 19 as shown in FIG.

  The configuration of the rotation transmission mechanism 19 will be described with reference to FIG. In the following description, the same components as those of the rotation transmission mechanism 50 using the conventional tension pulley described above with reference to FIG.

  The rotation transmission mechanism 19 includes a first input-side pulley 20 attached to an output shaft 2a (see FIG. 5) of a power source 2 (see FIG. 5) fixed to the base 1 (see FIG. 5). The first output side pulley 21 is attached to the first output side pulley 21 and the steel belt 6 is stretched between the first input side pulley 20 and the first output side pulley 21 (see FIG. 5). In the example shown in FIG. 3, unlike the rotation transmission mechanism 50 shown in FIG. 5, a second input side pulley 22 integrated with the first output side pulley 21 is provided. A steel belt 6 is similarly stretched between the pulley 23 and the pulley 23. The second output side pulley 23 is attached with a load 5 to be finally driven by gripping a workpiece or the like. In this case, in the rotation transmission mechanism 19, when the output shaft 2a of the power source 2 rotates, the first input-side pulley 20 rotates at the same rotational speed as the output shaft 2a. The first output pulley 21 rotates at a rotation ratio of (input pulley 20) / (output pulley 21). The rotation speed of the first output pulley 21 is the rotation speed of the second output pulley 22 as it is, and the rotation ratio of (input pulley 22) / (output pulley 23) via the steel belt 6 is as follows. The second output side pulley 23 rotates. As a result, the load 5 serving as the final load attached to the second output-side pulley 23 also rotates at the same rotational speed as the second output-side pulley 23.

  As shown in FIG. 3, the tension pulley 16 is arranged at two locations so as to press the steel belt 6 from the outer side of the ring toward the inner side of the ring.

  The operation of the tension pulley 16 attached to the rotation transmission mechanism 19 as described above will be described with reference to FIGS.

FIG. 1 is an explanatory diagram showing a state of contact between the outer ring 18 and the steel belt 6 in the tension pulley 16 of the present invention in the case where uneven contact occurs due to assembly dimension tolerance as shown in FIG. 4B. FIG.

  In the tension pulley, due to assembly dimensional tolerance, during the operation of the rotation transmission mechanism, the angle between the contact surface of the tension pulley and the contact surface of the steel belt is displaced as shown in FIGS. 4B and 4C, for example. There is a case where uneven contact occurs in the vicinity of the reference numeral 6 a of the belt 6.

  However, in the tension pulley 16 of the present invention, the O-rings 13a and 13b are deformed in accordance with the stress received from the steel belt 6, and the angle between the outer peripheral surface of the outer ring 8 and the axis of the inner shaft 11 can be automatically adjusted. it can. For example, in the conventional tension pulley 7, even when the steel belt 6 is in contact with only the upper part of the outer ring 8 and is in a driving state where it strikes unevenly as shown in FIGS. 4 (b) and 4 (c). In the tension pulley 16 of the present invention, since the O-rings 13a and 13b are deformed, the angle of the outer peripheral surface of the outer ring 18 with respect to the axis of the inner shaft 11 and the angle of the inner surface of the steel belt 6 with respect to the axis of the inner shaft 11 are different. It is corrected and adjusted to the same angle, so that uneven contact can be prevented.

That is, as shown in FIG. 4 (b), the tension pulley 16 of the present invention can be used in the conventional tension pulley, even when the contact is such that a large force is generated on the upper end side of the outer ring 8. As shown in FIG. 1B, the portions of the O-rings 13a and 13b located on the diagonal lines indicated by reference numerals 13a1 and 13b2 are deformed according to the input of the arrow 20, so that the inner shaft 11 on the outer peripheral surface of the outer ring 18 is deformed. The steel belt 6 and the outer peripheral surface of the outer ring 18 are always in surface contact with each other. FIG.1 (c) is the figure seen from the direction of the arrow 20 in FIG.1 (b) (the outer surface side of the steel belt 6), However, since the steel belt 6 does not strike unevenly, the wrinkle has not arisen. . As a result, the steel belt 6 is not subjected to local stress, and the life is extended.

  Next, FIG. 2 is an explanatory diagram showing a state of contact between the steel belt 6 and the outer ring 18 when sudden tension fluctuations generated from the load side occur.

  In the conventional tension pulley 7, sudden input is absorbed by the steel belt 6 itself.

However, in the tension pulley 16 of the present invention, the O-rings 13a and 13b are deformed according to the stress that the outer ring 18 receives from the steel belt 6. Therefore, when the tension change suddenly occurs, the O-rings 13a and 13b Can be absorbed.

That is, in FIG. 2, the tension pulley 16 receiving the force from the steel belt 6 side moves the outer shaft 18 in the direction of the arrow 24, so that the O-rings 13 a and 13 b of the reference numerals 13 a ₁ and 13 b in FIG. The portion indicated by 13b ₁ is deformed in response to the input, and the impact when sudden tension fluctuation occurs is absorbed by the O-rings 13a and 13b.

  The hardness and crushing allowance (cross-sectional shape and dimensions) of the O-ring 13 used in the tension pulley 16 of the present invention are appropriately selected according to the tension value of the steel belt.

  According to the experimental data conducted by the applicant, in the case of the conventional rotation transmission mechanism in which the cylindrical roller bearing is made of a hard material such as stainless steel, some modulation is applied to the steel belt 6 at a level that is less than 30,000 operations. In some cases, damage occurred. In the rotation transmission mechanism incorporating the tension pulley 16 of the present invention, no modulation was observed in the steel belt 6 even when the operation was performed 400,000 times or more. This operation check is under continuous evaluation, and it is certain that a longer life can be achieved.

  As mentioned above, although preferred embodiment of this invention was described with reference to the accompanying drawing, this invention is not limited to this embodiment, In the technical range grasped | ascertained from description of a claim, various It is possible to change to the form.

  In this embodiment, the O-ring 13a is attached to the accommodating portion 14a located on the distal end side of the inner shaft 11, and the O-ring 13b is attached to the accommodating portion 14a located on the proximal end side of the inner shaft 11. However, as the buffer member, for example, a plurality of O-rings may be mounted from the distal end side to the proximal end side of the inner shaft 11, or from the distal end side to the proximal end side of the inner shaft 11. It is also possible to adopt a configuration in which an elastic cylindrical body to be covered is attached.

(A) is a figure explaining the state which a steel belt contacts the tension pulley of this invention, Comprising: The explanatory drawing which made the tension pulley and the steel belt the cross section in the surface containing the axial center of an inner shaft. (B) is explanatory drawing which shows the state which the outer ring | wheel of the tension pulley shown in FIG. 1 (a) inclines with respect to the inner shaft, and the O-ring was crushed. (C) is explanatory drawing which looked at the state of FIG.1 (b) illustration from the direction of the arrow 20 in FIG.1 (b). (A) is explanatory drawing which showed the state similar to Fig.1 (a). FIG. 2B is an explanatory view showing a state in which the outer ring of the tension pulley shown in FIG. 2A receives the input from the steel belt, moves to the inner shaft side while maintaining equilibrium with the inner shaft, and crushes the O-ring. . The top view of the rotation transmission mechanism which attached the tension pulley of this invention. (A) is a figure explaining the state which a steel belt contacts the conventional tension pulley, Comprising: The explanatory drawing which made the tension pulley and the steel belt the cross section in the surface containing the axial center of an inner shaft. (B) is explanatory drawing which shows the state in which the steel belt contacted the outer ring | wheel of the tension pulley shown to Fig.4 (a). (C) is explanatory drawing which looked at the state of FIG.4 (b) illustration from the direction of the arrow 20 in FIG.4 (b). (A) is a top view of the rotation transmission mechanism which attached the conventional tension pulley. (B) is also a front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base 2 Power source 3, 20, 22 Input side pulley 4, 21, 23 Output side pulley 5 Load 6 Steel belt 7, 16 Tension pulley 8, 18 Outer ring 9 Inner ring 10 Cylindrical roller 11 Inner shaft 12 Roller receiver 13a, 13b O Ring 14 Collar 15 Bearing 17 Outer shaft 19, 50 Rotation transmission mechanism

Claims (2)

A tension pulley that adjusts the tension of an endless belt that is stretched between the input-side pulley and the output-side pulley of a rotation transmission mechanism that rotates the output-side pulley following the rotation of the input-side pulley ,
An inner shaft,
A collar portion made of a cylindrical body and attached to the inner shaft;
An outer ring made of a cylindrical body and having an outer peripheral surface in contact with the endless belt;
A bearing interposed between the collar portion and the outer ring;
An O-ring disposed between the inner shaft and the collar portion;
The collar portion includes an interposed portion in which the bearing is disposed, and an accommodating portion that extends outward from both edges in the axial direction of the interposed portion and in which the O-ring is disposed,
The tension pulley according to the present invention , wherein the inner wall surface of the housing part is located outside the inner wall surface of the interposition part in the radial positional relationship of the collar part . A rotation transmission mechanism used in a substrate transfer robot,
An input pulley ,
An output pulley that is rotated following the rotation of the input pulley ;
An endless belt stretched between the input pulley and the output pulley ;
A tension pulley for adjusting the tension of the endless belt,
The endless belt is a steel belt;
The rotation transmission mechanism according to claim 1 , wherein the tension pulley is the tension pulley according to claim 1 .

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