JP2003214509A - Belt type power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt type power transmission device for mass production which shortens assembling time and eliminates need for skill in assembly by simplifying a structure thereof and minimizing variations in snaking performance. <P>SOLUTION: This belt type power transmission device consists of an annular belt (27) and a driving pulley (28) rotating inscribing in the belt, a driven pulley (29) having an elastic body (40) between a rolling wheel (39) and an axial center, and a housing supporting them. By conducting assembly so that the center distance of the two pulleys (28) and (29) inscribing in the annular belt (27) is equal to or greater than a maximum center distance at free dimensions, the tension necessary for the belt is generated automatically. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to electrophotographic printers, copiers, printers for personal computers and the like, and power transmission using a belt for decelerating and accelerating the driving force of a motor in a state where the change in rotational speed is as small as possible. It is related to the mechanism.

[0002]

2. Description of the Related Art A steel belt used in a power transmission section of an electrophotographic printer or a copying machine is always applied with tension in order to prevent slippage.
The methods of applying tension to this belt are roughly classified into three methods.

The first method is to fix the axial distance between the driving pulley and the non-driving pulley, which is incorporated inside the belt, by slightly expanding it so that tension can be applied in the longitudinal direction of the belt. Specifically, both ends of the driven shaft that rotatably supports the driven pulley by bearings are fitted into the long holes formed in the housing. By the screw that is bored in
It has a mechanism that can fix the belt after applying tension to the housing.

As a second method, both ends of the driven pulley shaft are supported by an arm extending from another shaft center other than the shaft center of the driven pulley shaft, and the arms are placed in a direction in which tension is applied to the belt. Fix it with force, or
The belt is always stretched by spring force.

As a third method, a third tension pulley is provided separately from the driving pulley and the driven pulley and is pressed against the inner surface or the outer surface of the belt to generate tension on the belt.

[0006]

In the first method described above, the screw of the supporting portion of the pulley shaft is adjusted to
Tension is applied to the belt, but this screw adjustment requires that the belt be in the center of the Pulley width while watching the belt meandering by rotating the unit while it is in use. There were many faces. Since the steel belt has high rigidity, the adjustment is delicate and requires skill.

The tension of the belt can be measured by a sound wave, but since this measurement causes variations, it is necessary to repeat the variations to correct the variations, which takes time.

In the second method, it is necessary to uniformly push the arm supporting the tension pulley shaft to the left and right. In this method as well, the position is adjusted and fixed while the belt is rolling so that the belt does not meander. In addition, even in the system in which tension is constantly applied to the belt by the spring, it cannot be said that the spring is always equalized to the left and right.
It is a mechanism that is not suitable for mass production because it requires adjustment of the meandering of the belt and requires a lot of man-hours for assembly.

The third method requires a tension pulley and parts such as an arm and a spring for supporting the tension pulley, which makes the weight heavy and the manufacturing cost high, which is not suitable for mass production. . Further, regarding the assembling property, the same problems as those of the above-mentioned first method and second method are encountered.

The present invention has been made in view of the reduction of the number of parts and the assembling property in comparison with the above-mentioned conventional method, and an object of the present invention is to provide a belt drive mechanism which is simple and has a small number of parts, and which is suitable for mass production. I am trying.

[0011]

The first means of the belt type power transmission mechanism provided by the present invention is an annular belt (1) shown in FIGS. 1 and 2 and rotates while being inscribed in the belt (1). From the drive pulley (2), the driven pulley (6) having an elastic body (5) between the rolling wheel (3) and the shaft center (4), and a housing (not shown) supporting these. And the two pulleys (2) and (6) inscribed in the annular belt (1)
The ring-shaped belt (1) is assembled by incorporating the above-mentioned distance between the shafts which is stretched without applying a force and is equal to or larger than the maximum distance between the shafts in the free dimension.
It has a structure that allows tension to be retained.

The second means of the belt type power transmission mechanism provided by the present invention is, as shown in FIG. 3, an annular belt (7) and a driving pulley (8) and a driven pulley which are inscribed in the belt (7) and rotate. (9) and an idler pulley (1) having an elastic body (12) between the rolling wheel (10) and the shaft center (11).
3) and a casing (not shown) that supports them,
Between the rolling wheel (10) and the shaft center (11) in the drive pulley (8), the driven pulley (9), and the casing that supports them while being inscribed in the annular belt (7). A predetermined initial tension is given to the annular belt (7) by incorporating an idler pulley (13) having an elastic body (12) in such a dimension that the elastic body (12) is compressed by receiving a force. It is structured.

Here, the drive side pulley (8) and the driven side pulley (9) are respectively provided with respective shafts (14) (15).
Although not shown in the drawings, they are supported by the housings, though they are press-fitted so that the driving force can be transmitted.

Similarly, the shaft center (11) of the idler pulley (13) is fitted to the shaft (16) supporting it, and the center of the idler pulley (13) is closer to the belt than the center Q1 of the rolling wheels (10). It is supported by the housing by a bearing (not shown) provided at a position close to Q2. Therefore, the elastic body (12) between the rolling wheel (10) and the shaft center (11) is pressed, and the annular belt (7) is given an initial tension.

FIG. 4 shows an alternative of the second means of the belt type power transmission mechanism provided by the present invention, which is an annular belt (17), a drive pulley (18) which is inscribed in the belt (17) and is rotated and driven. Pulley (19), rolling wheel (20) and shaft center (2
1) is composed of an idler pulley (23) having an elastic body (22) and a casing (not shown) that supports these, and the drive pulley (23) is circumscribed to the annular belt (17). 18), a driven pulley (19) and an elastic body (22) of an idler pulley (23) having elasticity between the rolling wheel (20) and the shaft center (21) in the casing supporting them. Is so constructed as to receive a force and be compressed so that a predetermined initial tension is applied to the belt (17) having the ring shape.

Here, the drive side pulley (18) and the driven side pulley (19) are respectively provided with respective shafts (24) (2).
5) is press-fitted so that the driving force can be transmitted.

Similarly, the shaft center (21) of the idler pulley (23) is fitted to the shaft (26) that supports the idler pulley (23), and its center is closer to the belt than the center Q3 of the rolling wheels (20). It is supported by a bearing of a casing (not shown) provided at a position close to Q4. Therefore, the rolling wheel (20) and the shaft center (2
The elastic body (22) located between (1) and (1) is pressed, and the annular belt (17) is thereby given an initial tension.

The third means provided by the present invention is the belt type power transmission mechanism according to claim 1 or 2, wherein the material of the annular belt is metal.

According to the fourth means provided by the present invention, the material between the rolling wheels and the shaft center is rubber, and the fourth means is rubber.
Is a belt type power transmission mechanism.

According to the fifth means provided by the present invention, the material between the rolling wheel and the shaft center is a metal, and the fifth means is a metal.
Is a belt type power transmission mechanism.

[0021]

The first aspect of the belt type power transmission mechanism provided by the present invention
The operation of the means will be described with reference to FIGS. In order to transmit power by a power transmission mechanism using a belt, an initial tension is required between a belt having an annular shape and a drive pulley and a driven pulley inscribed in the belt.

The belt has a characteristic of a tension spring which is stretched by tension, and the relationship between the rolling wheel of the driven pulley and the shaft center is a combined characteristic of the compression spring and the tension spring, and the characteristic of the combined spring is one. It has a characteristic equivalent to that of a spring.

Therefore, the initial tension of the belt is the maximum axial distance in the free state of FIG. 1 in which no tensile force is applied between the driving pulley (2) and the driven pulley (6) inscribed in the belt (1). By further expanding from, the composite spring constant can be applied and calculated.

FIG. 2 shows the dimensional relationship at the time of assembly. The belt elongation (1) when the initial tension capable of transmitting the required torque to the belt (1) is applied and the rolling wheel of the driven pulley (6) ( 3) Sum of compression amounts δ2 of shaft center (4) δ3
Only unfolded and incorporated into the case.

If an inter-axis dimension capable of giving an initial tension capable of transmitting a required torque is calculated and manufactured in advance, a unit in which a desired tension is set can be completed only by assembling.

The claim 2 is a little different from the above-mentioned one and is complicated, but in FIG.
0) and the center of axis of the idler pulley (13) having elasticity between the center of axis (1) rather than the center Q1 of the rolling wheel (10).
By arranging the center Q2 of 1) close to the annular belt (7), the elastic body (12) can apply an initial tension to the belt (7) having an annular shape by pushing the belt. Finally, power can be transmitted.

The invention of claim 2 is disadvantageous in that it has a large number of parts as compared with claim 1, but is added to the elastic body (12) between the rolling wheel and the shaft center in claim 1. The rotational torque force is not transmitted. Therefore, the rigidity of connection between the drive shaft and the driven shaft is high, and the rotational characteristics of the drive shaft can be transmitted in a relevant manner.

Further, as for the force applied to the elastic body (12) between the rolling wheel and the shaft center, since the contact angle with the belt is small, a large force can be generated in the belt with a small force, so that the elastic body is soft. This is advantageous in terms of durability of the elastic body.

Another alternative of the embodiment of claim 2 will be described with reference to FIG. The present invention is as shown in FIG.
0) and the axial center (21) are different in that the position of the idler pulley (23) having elasticity is located outside the annular belt, but the characteristic advantage with respect to claim 1 is the same. . In contrast to the means shown in FIG. 3, the means shown in FIG. 4 allows the belt contact angle θ with respect to the drive shaft to be large, whereby the initial tension of the annular belt can be set low. However, in the means of FIG. 4, the bending direction of the annular belt is changed from the straight state to the pulley side.
In contrast to the direction, the means of FIG. 4 is disadvantageous in durability because the idler pulley (23) is outside the annular belt (17) and therefore the annular belt material undergoes both-end bending durability. . In any case, the selection of these overall configurations is also determined by the relationship with other parts other than the drive system, and expands the degree of freedom in design.

Claims 1 and 2 of this patent can be applied to various belt materials, but in particular, claim 3 defines a metal belt having high belt rigidity. Above all, the stainless steel belt has a thin plate thickness of 20 to 60 μm and therefore has a high bending durability and a high rigidity in the longitudinal direction. Therefore, if the belt circumferential length is accurately created without variation, the belt tension will be the same as that of the rolling wheels and the shaft center. Since the characteristics between solids do not vary even if the elastic body between them is not so large, it can be manufactured as a speed reducer for mass production.

[0031]

Embodiment 1 An embodiment of a belt type power transmission mechanism provided by the present invention is shown in FIGS. In FIG. 5, (2
Reference numeral 7) is an annular belt, which is stretched under the condition that initial tension is applied by the driving pulley (28) and the driven pulley (29). The drive pulley (28) is a drive motor (3
0) The shaft (31) is press-fitted so that the driving torque can be transmitted.

Although not shown, the motor (30) is fastened to the case A (32) by bolts. Further, this casing A is fastened to the casing B of (33) by the bolts (34) shown in FIG. 6 so as to form one box shape, and is driven by the bushes (35a) and (35b), respectively. The shaft (36) is supported so as to be freely rotatable.

The driven shaft (36) is press-fitted to the inner wheel hub portion (37) of the driven pulley so that torque can be transmitted, and the outer diameter portion of the outer ring portion (38) and the inner diameter portion of the rolling wheel (39). An elastic body (40) such as rubber or urethane is assembled between them and so that torque can be transmitted by adhesion or press fitting.

In FIG. 6, the annular belt (27), the driving pulley (28), and the driven pulley (29) are arranged between the shafts rather than between the shafts in the free dimension where no force is applied between them. The distance is set wide.

Therefore, the annular belt (2
7) is in a slightly stretched state, and the driven pulley (29) is in a state in which the elastic body (40) is widened between the two shafts on the motor side and the side opposite to the driven shaft (36) is crushed. Incorporated.

Since these relations are the relations obtained in advance as described in the above operation, the initial tension is automatically set on the annular belt (27) by assembling.

The embodiment of claim 2 is shown in FIGS.
5 and FIG. 6 are combined, the configuration thereof can be easily imagined, so the display is omitted. In the same manner, the display of claim 3 is omitted.

[0038]

[Embodiment 2] An embodiment of claim 4 will be described. The driven pulley already shown in FIG. 5 and FIG. 6 is a key component of the present invention, and the elastic body (40) may be rubber or various foams. Further, in terms of characteristics, rubber having anti-vibration characteristics can also be used for improving the sound and vibration characteristics of the speed reducer.

In the case of the construction as claimed in claim 2 in FIGS. 3 and 4, the idler pulleys (13) and (23) have a small contact angle φ with the belt, so that even if a slight pressing load is applied, a large tension is applied to the belt. To occur. Therefore, it is desirable that the spring constant of the elastic body be small, and a foamed material such as rubber is used to provide a cohesive product.

[0040]

[Embodiment 3] On the other hand, in the case of the construction as claimed in claim 2 in FIGS. 1 and 2, the elastic body (5) of the driven pulley (5).
Since the initial tension of the belt is directly applied to, the spring constant of the elastic body requires a large value. Further, since a large load is constantly applied, the spring characteristic using a metal as claimed in claim 5 is preferable to the material that causes creep.

7 and 8 show another embodiment of the driven pulley of claim 1 and the idler pulley of claim 2. In the present invention, the shaft center portion (41) of the driven pulley and the rolling portion (42) of the outer ring are integrally press-molded from a thin plate, and the portion corresponding to the spoke portion (43) in the middle is disc-shaped. In addition, the cross section is wavy to give elasticity, and the shape is simple, and the method is suitable for mass production.

[0042]

Fourth Embodiment FIGS. 9 and 10 show another embodiment of the driven pulley according to claim 1 and the idler pulley according to claim 2. The present invention relates to a deformation spring (46) having a star-shaped spoke-shaped cross-section between the shaft center portion (44) of the driven pulley and the rolling portion (45) of the outer ring.
Is attached by welding or press fitting so that the spring constant in the radial direction can be made softer than in the second embodiment.

Although the purry of claim 1 has been described as the driving side and the driven side, this can be used in reverse as a function depending on the reduction ratio of the corresponding unit.
Further, although the above drawings have shown only an example of one-step deceleration, it is easily conceivable that the number of steps can be increased to two steps or three steps when the reduction ratio is large. Further, the present invention can also be used as a belt conveyor for carrying an object by placing an object on the belt.

[0044]

As described above, the axial distance between the drive pulley inscribed in the annular belt and the driven pulley having elasticity between the rolling wheel and the shaft center is the maximum shaft distance when the dimension is free. By incorporating the above, a stable initial tension with little variation among individuals can be added to the annular belt during assembly. Further, since the number of parts can be reduced and the adjustment time at the time of assembly can be shortened, it is possible to cope with mass production.

A driving pulley and a driven pulley which are inscribed and rotated in an annular belt, and an idler pulley which is inscribed in or circumscribed in the annular belt and has an elastic body between a belt rolling wheel and a shaft center. And a driven pulley which is inscribed in the annular belt, and a driven wheel which is inscribed in or circumscribed in the annular belt in the casing which supports them and which is inscribed in the annular belt. By incorporating the elastic body of the idler pulley which has elasticity into the elastic body of the idler pulley, the rotational torque is not transmitted to the elastic body of the idler pulley, and the belt is passed through the drive shaft. Since the driven shaft can be directly driven, the rotation of the motor can be transmitted to the driven shaft in a relevant manner. Also,
Since the idler pulley has a small contact angle with the belt, a large amount of tension can be generated in the belt even with a small force, and a strong force is not applied to the elastic body, so that the durability can be improved.

[Brief description of drawings]

FIG. 1 is an auxiliary diagram for explaining the concept of the present invention.

FIG. 2 is a conceptual explanatory diagram of the present invention.

FIG. 3 is a conceptual diagram of claim 2 of the present invention.

FIG. 4 is another conceptual diagram of claim 2 of the present invention.

FIG. 5 is a first embodiment of the present invention.

FIG. 6 is a sectional view taken along line AA of FIG.

FIG. 6 is a first embodiment of the present invention.

FIG. 5 is a view on arrow B of FIG.

FIG. 7 is a front view of a third embodiment of the present invention.

[Figure 8]

FIG. 7 is a sectional view taken along line AA of FIG.

FIG. 9 is a front view of a fourth embodiment of the present invention.

[Figure 10]

FIG. 9 is a sectional view taken along line AA of FIG.

[Main part names]

1 ... Annular belt 2 ... Drive pulley 5 ... Elastic body 6 ... Driven pulley having elasticity between belt rolling surface and shaft center

Claims (5)

[Claims] 1. An annular belt, a drive pulley which is inscribed in the belt and rotates, a driven pulley which has elasticity between a rolling wheel and an axis which are inscribed in the belt, and a casing which supports these. And a belt type power transmission mechanism in which the axial distance between the two pulleys inscribed in the annular belt is equal to or greater than the maximum axial distance in the free dimension. 2. An annular belt, a drive pulley and a driven pulley which are inscribed and rotated in the belt, an idler pulley having elasticity between a rolling wheel and a shaft center, and a casing which supports these. An elastic body of an idler pulley that has elasticity between the rolling wheel and the shaft center in the drive pulley, the driven pulley and the casing that supports them in a state of being inscribed or circumscribed in the annular belt. A belt-type power transmission mechanism having a size so as to be compressed by receiving a force between the belt and the belt. 3. The material of the annular belt is metal.
Alternatively, the belt type power transmission mechanism according to claim 2. 4. The belt type power transmission mechanism according to claim 1, wherein the material of the elastic body between the rolling wheels and the shaft center is rubber. 5. The belt type power transmission mechanism according to claim 1, wherein the elastic body between the rolling wheels and the shaft center is made of metal.