JP2002098202A - Toothed belt transmission device and business equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothed belt transmission device for use in business equipment or the like such as a printer and copier, in which unevenness in the toothed belt 8 speed is reduced to possible minimum and the printing accuracy and image quality of the business equipment are enhanced. SOLUTION: The tooth part 13 of the belt 10 is composed of a pair of dedendum parts 14, a pair of tooth flanks 15 consisting of convex circular arc surfaces, and a tooth tip 16 continuing the two tooth flanks 15 and consisting of circular arc surface parts 17 continuing to the circular arc surfaces of the tooth flanks 15 and one plane 18 whereby the two circular arc surface parts 17 are connected together, while each pulley tooth groove part 3 of a toothed pulley 1/2 is composed of a pair of tooth crest circular arc parts 4, a pair of tooth groove side faces 5 consisting of concave circular arc surfaces, and a tooth groove bottom part 6 formed so that the two tooth groove side faces 5 are connected together, and in the transmitting condition in which the belt 10 is wound on pulleys 1 and 2, the belt land part 12 and pulley periphery 9 are held out of contact. When the belt tooth 13 bites into the pulley tooth groove part 3, rotation is generated round the point O' on the belt pitch line PL mating with the area around the back dedendum of the pulley tooth groove part 3 adjoining to the front in belt running direction of the applicable pulley tooth groove part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt transmission and office equipment using the same, and more particularly to a technical field for reducing uneven speed (speed fluctuation) of a belt.

[0002]

2. Description of the Related Art Conventionally, as this type of toothed belt, a belt having a trapezoidal shape in a belt tooth portion has been generally used. However, it is possible to transmit a higher load or reduce noise. For the purpose of further reduction, a belt having a toothed shape having a convex side surface has been proposed, and is now mainstream. One of the tooth profiles is disclosed in Japanese Patent Laid-Open No. 50-42252.
The other is a so-called HTD-II tooth profile shown in Japanese Patent Application Laid-Open No. 59-89852.
For example, the former STPD tooth profile is commercialized as a product name “Super Torque Synchro Belt” of Bando Chemical Co., Ltd., and the latter HTD-II tooth profile is commercialized as a product name “Power Grip GT Belt” of Unita Corporation. ing.

In addition, Japanese Patent Laid-Open Publication No. Sho 64-74 discloses a technique for precisely positioning and driving a movable part in office equipment.
No. 341 also proposes a toothed belt.
In this embodiment, as shown in FIG. 15, a plurality of belt teeth 13 ', 13',... (Only one is shown) are provided at a constant pitch on a land line LL of a main body 11 'of a belt 10'. The belt tooth portion 13 'has a center line C2 in the tooth width direction.
Root portion 14 'consisting of an arc surface symmetrically arranged with respect to
14 ', and tooth side portions 15', 15 'formed of convex arcuate surfaces continuous with the root portions 14', 14 'and provided symmetrically with respect to the tooth width direction center line C2. The center line C which is continuous with the tooth side portions 15 ', 15'
Arc surface part 1 consisting of an arc surface provided symmetrically to 2
7 ', 17', and these arc surface portions 17 ', 17'
The parts are connected by a plane part 18 'composed of one plane. Then, in a state where the toothed belt 10 'is statically engaged with the toothed pulley 1', each belt tooth portion 13 '
Of the pulley tooth groove 3 'of the belt tooth 13', the backlash in the pulley tooth groove 3 'of the belt tooth 13' starts from the tooth root of the belt tooth 13 '. The depth of the pulley tooth groove 3 ′ gradually increases toward the
It is configured so as to have a height of 3 'or more.

In this apparatus, the backlash with the pulley tooth groove 3 'is eliminated at the root 14' of the belt tooth 13 ', while the backlash with the pulley tooth groove 3' is adjusted to the tooth of the belt tooth 13 '. The belt teeth 13 'are gradually narrowed toward the teeth by gradually increasing from the root to the teeth, thereby suppressing the interference of the meshing between the belt teeth 13' and the arcuate portions 4 'of the pulley tooth grooves 3'. Thus, the fluctuation of the belt pitch line PL caused by the meshing interference is reduced.
In FIG. 15, reference numeral 5 'denotes a concave tooth groove side surface in the pulley tooth groove 3', and reference numeral 6 'denotes a tooth groove bottom. Also, belt 1
The pitch line PL of 0 'coincides with the pitch circle PC of the pulley 1'. In addition, in order to facilitate understanding, FIG.
In the figure, the outer peripheral portion of the pulley 1 'is shown in a developed state together with the belt 10'.

[0005]

In office equipment such as printers and copiers, a printing apparatus (including image printing) using a toothed belt transmission is generally used. In this printing apparatus, a carriage equipped with a printing mechanism such as ink or a hammer is attached to a toothed belt, and the toothed belt is passed between toothed pulleys.
The carriage is reciprocated by rotating the pulley forward and backward.

[0006] In order to improve printing accuracy and image quality by the carriage, it is required to reduce as much as possible non-uniformity in speed (speed fluctuation) during running of the toothed belt. In particular, in recent years, in printers, color printing and its high speed and high image quality have been rapidly progressing, and the meshing vibration (speed unevenness due to meshing) of the toothed belt may cause printing unevenness and image unevenness. Therefore, there is a strong demand for reduction in unevenness in the meshing speed of the toothed belt.

For office equipment such as printers, toothed belts having a tooth pitch of 3 mm or less (for example, 3 mm, 2 mm, 1.5 mm, etc.) having the above-mentioned STPD tooth shape or HTD-II tooth shape are generally used. And the shape of the teeth is 8mm
A shape in which a tooth profile having a relatively large tooth portion pitch, such as a pitch or a 5 mm pitch, is reduced substantially similar as it is is adopted.

However, these tooth profiles were originally developed for the purpose of high load transmission, and therefore no consideration has been given to the requirement for reducing the above-mentioned uneven speed.

The toothed belt disclosed in Japanese Patent Application Laid-Open No. 64-74341 has been proposed in consideration of the reduction of the speed unevenness to some extent. However, the toothed belt has an optimum tooth profile for reducing the speed unevenness. And it was insufficient to reduce the unevenness of the speed as much as possible.

In other words, studies on the tooth shape for reducing the speed unevenness of the toothed belt have hardly been performed in the past.

In view of the above, the present invention has been made by the inventor of the present invention by intensively analyzing and experimenting on various factors constituting the tooth shape of the toothed belt used in office equipment as described above. The purpose is to reduce the uneven speed of the toothed belt as much as possible.

[0012]

In order to achieve the above object, as a result of research conducted by the present inventors, in a toothed belt having a convex arcuate surface on the side surface of a belt tooth portion, the belt is wound around a pulley. Paying attention to the fact that when the tooth portion rotates and meshes with the tooth groove portion of the pulley, the belt tooth portion rotates around a point on the belt pitch line, and in a state where the belt tooth portion meshes with the pulley tooth groove portion. By lifting the land between the belt teeth from the pulley outer diameter (tooth crest) between the pulley tooth grooves, the center of rotation on the pitch line when the belt teeth mesh with the pulley tooth grooves is moved in the belt running direction. By shifting to the front side, the interference at the time of meshing the belt tooth portion with the pulley tooth groove portion is more effectively suppressed.

More specifically, according to the first aspect of the present invention, a belt body having a tensile member embedded on a pitch line and a plurality of belt teeth provided at a constant pitch on a land line of the belt body are provided. The present invention is directed to a toothed belt transmission which is a combination of a toothed pulley provided with a pulley having a plurality of pulley tooth grooves provided at a constant pitch on a pulley outer diameter line.

[0014] Each tooth portion of the toothed belt has a root portion formed of a substantially arcuate surface symmetrically arranged with respect to a center line in the tooth width direction, and a tooth side surface continuous with the tooth root portion. A tooth side surface portion that is located and is symmetrical with respect to the center line in the tooth width direction and that is formed of a substantially arcuate surface of a convex shape, and is located closer to the root of the tooth than the extension line on the tooth tip side of the arc surface of both tooth side surfaces. An arc-shaped surface portion formed of a substantially arc-shaped surface provided so as to be continuous with the arc-shaped surface of both tooth side surface portions, and a tooth tip portion formed of a substantially flat surface provided to connect the two arc-shaped surface portions. And On the other hand, each pulley tooth groove part of the toothed pulley has a tooth root arc part consisting of a substantially circular arc surface symmetrically arranged with respect to the tooth groove width direction center line, and a tooth root width direction center continuous with the tooth root arc part. It is composed of a tooth groove side surface portion having a substantially arcuate concave shape provided symmetrically with respect to the line, and a tooth groove bottom portion provided so as to connect the two tooth groove side surface portions to each other. Further, in a transmission state in which a pulley is wound around the belt and tension is applied to the belt, the land portion between the belt teeth of the belt main body and the pulley outer diameter portion (tooth crest) are brought into a non-contact state.

According to a second aspect of the present invention, as a toothed belt transmission similar to the object of the first aspect of the present invention, each tooth portion of the toothed belt is symmetrically disposed with respect to a center line in a tooth width direction. A tooth root portion formed of a substantially circular arc surface, and a tooth side surface portion formed of a substantially circular arc surface having a convex shape provided on the tooth side surface continuously to the tooth root portion and provided symmetrically with respect to the center line in the tooth width direction. From one arc surface which is located closer to the root of the tooth tip side extension line of the arc surface of both tooth side surfaces, is continuous with the arc surface of both tooth side surfaces, and has a center point on the center line in the tooth width direction. And a tooth tip. On the other hand, each pulley tooth groove part of the toothed pulley has a tooth root arc part consisting of a substantially circular arc surface symmetrically arranged with respect to the tooth groove width direction center line, and a tooth root width direction center continuous with the tooth root arc part. It is composed of a tooth groove side surface portion having a substantially arcuate concave shape provided symmetrically with respect to the line, and a tooth groove bottom portion provided so as to connect the two tooth groove side surface portions to each other. Then, in a transmission state in which the pulley is wound around the belt and tension is applied to the belt, the land portion between the belt teeth of the belt body and the outer diameter portion of the pulley are brought into a non-contact state.

According to the constructions of the present invention, when the belt is wound around the pulley, the land portion of the belt is wound around the outer diameter portion of the pulley in an arc shape, and after the land portion is wound, the belt tooth portion bites into the pulley tooth groove portion. At this time, in a normal case where the belt land portion and the pulley outer diameter portion come into contact with each other when the belt tooth portion and the pulley tooth groove portion mesh with each other, the belt tooth portion is located on the pitch line of the belt main body in the belt running direction. It is engaged with the pulley tooth groove portion while rotating around a point corresponding to the root arc portion (the front end in the running direction of the pulley tooth groove portion) near the root as a rotation center (fulcrum). On the other hand, in the structure in which the belt land portion and the outer diameter portion of the pulley are in a non-contact state as in each of the inventions, when the belt tooth portion bites into the pulley tooth groove portion, the rotation center of the belt tooth portion is The reason is that the belt land portion is separated from the outer diameter portion of the pulley, not at the point corresponding to the root arc portion near the root at the front side of the belt running direction of the pulley tooth groove portion to be engaged as described above. Then, the target pulley tooth groove is shifted to a point corresponding to the root arc in the vicinity of the rear root of the pulley tooth groove adjacent to the front side of the pulley tooth groove in the belt running direction. As it moves, it will bite into the target groove of the pulley. As a result, the turning radius of the belt tooth portion becomes larger than that in the case where the belt land portion and the outer diameter portion of the pulley are in contact with each other, and the amount of protrusion of the turning locus on the tooth tip side of the tooth side surface portion. And the belt teeth hardly interfere with the tooth groove side surface of the pulley tooth groove, and the belt tooth smoothly slides into the pulley tooth groove, causing uneven belt speed due to interference of the belt tooth with the pulley tooth groove. Can be further reduced.

Generally, the transmission of the load between the pulley and the toothed belt in the toothed belt transmission device includes not only the meshing transmission between the pulley tooth groove portion and the belt tooth portion, but also the pulley outer diameter portion and the belt land portion. The fluctuation of the rotation speed of the pulley is transmitted to the toothed belt by these two transmission modes, and the speed unevenness of the toothed belt occurs. Is in a non-contact state, the latter friction transmission between the outer diameter portion of the pulley and the belt land portion of the load transmission mode between the pulley and the belt is removed. Transmission of the rotation speed fluctuation to the belt is prevented. A portion of the belt tooth portion between the belt land line and the outer diameter line of the pulley absorbs the fluctuation of the rotation speed of the pulley due to its elasticity. Thus, the transmission to the belt can be suppressed, and the speed unevenness of the belt can be further reduced.

Further, in particular, according to the first aspect of the present invention, the tip of the belt tooth portion is formed by an arcuate surface portion formed of a substantially arcuate surface provided so as to be continuous with the arcuate surfaces on both side surfaces, and both of these arcuate surface portions. Since it is constituted by one substantially flat surface portion provided so as to be connected, the following operation and effect can be obtained. That is, in a printer application, a driven pulley (FIG. 3)
Pulley 2) may be used as a flat pulley. In this case, the tip of the belt tooth portion runs in direct contact with the outer diameter portion of the flat pulley. If the load is applied to a large area, the position of the pitch line can be stabilized, whereby the unevenness of the belt speed can be suppressed.

On the other hand, in the second aspect of the present invention, the tooth tip of the belt tooth portion is constituted by one arc surface which is continuous with the arc surfaces of both tooth side surfaces and has a center point on the center line in the tooth width direction. Therefore, the contact of the belt tooth portion with the pulley tooth groove portion can be further delayed as compared with the one having a flat portion at the tooth tip portion as in the invention of claim 1 (see the phantom line in FIG. 10) (FIG. 10). As shown in the solid line), there is an advantage that the speed unevenness of the belt can be further reduced as described later in the description of the third aspect.

According to the third aspect of the present invention, when the tooth root width of the toothed belt on the land line is W, the tooth side surface of the belt tooth portion has a tooth height of 0.3 from the land line in the tooth height direction.
The pressure angle at a reference position W away (hereinafter also referred to as 0.3 W pressure angle) is set to 26 to 39 °. This is preferable because unevenness in the speed of the belt can be further reduced.

That is, in a toothed belt in which the side surfaces of the belt teeth are convex, the pressure angle at the reference position on the side surface has a very large effect on the speed unevenness. The reason for this is that the convex tooth side surface of the belt tooth side is usually 0.6 W
This is because, since it has front and rear tooth heights, the “0.3 W pressure angle” at the reference position at the center of the tooth height is a substantially effective index as the pressure angle of the convex tooth shape.

The conventional toothed belt having the STPD tooth profile or the HTD-II tooth profile aims at high load transmission, and therefore, in order to avoid belt jumping (jumping) under a high load, the above-mentioned toothed belt on the side of the tooth portion is used. .3W pressure angle is set small. For example, ST with a tooth pitch of 1.5 to 3.0 mm
For a PD tooth profile, the above 0.3 W pressure angle is 25.1 to 25.3.
°, and 1.5-3.0 mm pitch HTD-
In the II tooth profile, the 0.3 W pressure angle is set in the range of 20.8 to 21.1 °. On the other hand, since the toothed belt used for office equipment is driven under light load transmission conditions, there is almost no need to consider the tooth jump of the belt as described above. According to the results of the study by the inventor, by setting the 0.3 W pressure angle on the side surface of the tooth portion to 26 to 39 degrees, the unevenness of the belt speed can be greatly reduced. And
When the belt pitch line moves up and down in the direction perpendicular to the belt span in the belt span (the part not wound around the pulley), the meshing speed unevenness occurs. The amount of vertical movement of the pitch line is determined by the reaction force generated when the belt tooth slides into the pulley tooth groove, and the component force of the belt tension generated when the belt is pushed upward by the reaction force. For this reason, as the contact position becomes farther from the complete meshing position between the belt tooth portion and the pulley tooth groove portion, the component force of the belt tension becomes smaller, and the push-up amount of the pitch line becomes larger. In other words, the earlier the belt teeth contact the pulley tooth grooves, the greater the speed unevenness.

Therefore, as in the conventional tooth shape, 0.3 W
When the pressure angle is small, the side surface of the belt tooth portion comes into quick contact with the side surface of the pulley tooth groove portion (see FIG. 5B), whereas the 0.3 W pressure angle is larger than the conventional one as in the present invention. And the contact between the belt teeth and the side surfaces of the pulley teeth grooves is slowed down (see FIG. 5A), whereby the unevenness of the belt speed can be reduced.

On the other hand, the 0.3 W pressure angle cannot be increased indiscriminately, and if it is too large, the speed unevenness increases. That is, as described above, the amount of movement of the belt span is determined by the reaction force that slides after the side surface of the belt tooth portion comes into contact with the side surface of the pulley tooth groove portion and the component force of the belt tension. If it ’s too big,
This is because the component in the vertical direction (the direction orthogonal to the belt span) of the reaction force generated when the belt tooth portion slides into the pulley tooth groove portion becomes too large, so that the belt pitch line cannot be easily slipped and the belt pitch line is pushed up.

Therefore, if the 0.3 W pressure angle is in the range of 26 ° to 39 ° as described above, the optimum allowable range can be obtained, and the conventional pressure angle (for example, 25.1 to 25.3) is obtained.
°) is extremely effective in reducing belt speed unevenness as compared with those having (°).

According to the fourth aspect of the present invention, the land portion of the toothed belt is substantially flat. Thus, the effect of the first or second aspect of the invention can be effectively obtained.

According to the fifth aspect of the present invention, the tooth side surface of the belt tooth portion of the toothed belt and the tooth groove side surface of the pulley tooth groove portion of the toothed pulley are substantially similar in shape, and the pulley is wound around the belt so that tension is applied to the belt. , The pressure angles at the respective tooth height direction positions of the tooth side surface portion of the belt tooth portion and the tooth groove side surface portion of the pulley tooth groove portion are made substantially equal.

As described above, if the pressure angle of the toothed belt having the convex arcuate tooth side surface portion is set to be within an appropriate range, the contact with the pulley tooth groove portion can be delayed. Although it has the effect of reducing the speed unevenness, a greater effect can be exhibited by combination with the pulley tooth groove shape. That is, Japanese Patent Application Laid-Open No. Sho 64-74341 discloses a conventional technique which aims at reducing speed unevenness by combining a belt tooth shape and a pulley tooth groove shape. As described above, as described above, the backlash between the belt tooth portion and the pulley tooth groove portion gradually increases from the tooth tip portion toward the tooth tip side (that is, the pressure angle of the pulley tooth groove side surface is larger than the belt tooth side surface pressure angle). By reducing the pressure angle), it is intended to suppress interference of the belt teeth with the pulley tooth grooves during biting (see FIG. 15).

In this configuration, however, interference does not occur substantially in the no-load transmission state, but in reality, as described above, in the normal transmission state, the belt teeth are pulled by the influence of the applied load torque. Since the tooth is engaged at a position slightly delayed from the position of the tooth groove, the tooth side surface on the rear side in the belt running direction contacts the side surface of the pulley tooth groove, and then slides in. At this time, as in the conventional example, the pressure angle on the side surface of the belt tooth is
When the pressure angle on the side face of the pulley tooth groove is reduced, the side face of the belt tooth part comes into contact with the root arc part of the pulley tooth groove part, and the belt tooth part bites while being pushed up by the root arc part of the pulley tooth groove part (FIG. 6 ( b)). As a result, the belt pitch line cannot be smoothly slid into the tooth groove portion of the pulley, and the belt pitch line is pushed up to increase the speed unevenness. In fact, in the analysis of the speed unevenness using the finite element method, the speed unevenness becomes worse for the same pressure angle between the belt and the pulley.

On the other hand, according to the structure of the fifth aspect of the invention, since the pressure angle at each position in the tooth height direction between the side surface of the belt tooth portion and the side surface of the tooth groove of the pulley tooth groove is substantially equal, the meshing of the tooth is possible. When the belt teeth are inserted, the side surfaces of the belt teeth uniformly contact the side surfaces of the pulley tooth grooves, so that the belt teeth smoothly slide into the pulley tooth grooves, and the belt pitch line is not pushed up (see FIG. 6A). Therefore, in combination with the fact that the pressure angle on the side surface of the belt tooth portion is larger than before, the belt tooth side surface is in slow contact with the pulley tooth groove side surface, and the belt speed unevenness can be extremely suppressed.

According to the invention of claim 6, as the office equipment,
It is assumed that the toothed belt transmission is provided and a carriage is attached to the toothed belt. Thus, when the printing is performed by moving the carriage during operation of the toothed belt transmission, fluctuations in the speed of the carriage due to uneven speed of the belt are reduced, so that printing accuracy and image quality by the carriage can be improved. .

[0032]

(Embodiment 1) FIG. 3 shows the overall structure of a toothed belt transmission A according to Embodiment 1 of the present invention. This transmission A is an office work represented by a printer or a copying machine. It is to be equipped with the equipment. In FIG. 3, 1
Is a drive pulley composed of a toothed pulley, and 2 is a similar driven pulley. These pulleys 1 and 2 are arranged, for example, in the horizontal direction. Synchronous belt 10 between both pulleys 1 and 2
Are wound in a meshing state, and a printing mechanism (not shown) such as ink or a hammer is provided on a lower side span of the toothed belt 10.
Is mounted and fixed integrally with the mounting portion 24a, and the drive pulleys 1 and 2 are rotated forward or backward to move the toothed belt 10 to travel.
The carriage 24 is reciprocated between the pulleys 1 and 2.

As shown in enlarged form in FIG. 2, the driving or driven pulleys 1 and 2 composed of the toothed pulleys are provided at a constant pitch on a pulley outer diameter portion 9 on a pulley outer diameter line on the outer circumference. Pulley tooth grooves 3, 3, ... (only one is shown)
It has. Each of the pulley tooth groove portions 3 includes a pair of tooth root arc portions 4, 4 each formed of an arc surface having an arc radius r 1 P arranged symmetrically with respect to the tooth groove width direction center line C 1, and these two tooth root arc portions 4. , 4 and symmetrically with respect to the center line C1 in the tooth groove width direction and in the vicinity of the pitch circle PC (the arc surface of the tooth side surface portion 15 of the tooth portion 13 of the belt 10 meshing with the pulleys 1 and 2 as described later). An arc radius RP (>) that has a center point O1P at the same position as the center point O1B and is slightly larger than an arc radius RB of a tooth side surface portion 15 of the belt tooth portion 13 described later.
RB), a pair of tooth groove side surfaces 5, each having a concave circular arc surface,
5 and a tooth groove bottom portion 6 provided so as to connect the two tooth groove side surface portions 5 and 5. The tooth groove bottom portion 6 connects the two tooth groove side surface portions 5 and 5 to each other. It is composed of arcuate surface portions 7, 7 each having a substantially arcuate surface provided, and one flat surface portion 8 having an approximately flat surface provided to connect the two arcuate surface portions 7, 7 (see FIG. In FIG. 2, the outer peripheries of the pulleys 1 and 2 are shown in an unfolded state together with the belt 10 for easy understanding).

On the other hand, the toothed belt 10 has a belt body 11 made of an elastic material as shown in an enlarged view in FIG. The belt body 11 is preferably made of rubber or polyurethane, and may be made of a material such as a synthetic resin. In the case of rubber, chloroprene rubber is used, and NBR, SBR, EPDM or the like may be used. The hardness of the rubber is preferably about 65 to 85 ° in JIS-A. When the belt body 11 is made of polyurethane, the polyurethane is a thermosetting and ether-based polyurethane, but may be a thermoplastic or ester-based polyurethane.

A cord (not shown) as a tensile member is embedded on the pitch line PL of the belt body 11. Regardless of whether the belt main body 11 is made of rubber or polyurethane, the core wire mainly uses glass fiber or aramid fiber, and may be a fiber such as carbon or PBO. Also, to reduce the power consumption of office equipment,
A small-diameter core wire is desirable so as to reduce the loss torque.

Further, in view of reducing the speed unevenness of the belt 10, in order to stably maintain the pitch line PL of the belt 10, the bending rigidity of the belt 10 is reduced.
Considering that the tensile elasticity of the belt 10 is increased in order to reduce the meshing interference by maintaining the tooth pitch PB when the load is applied and to quickly attenuate the speed fluctuation at the time of starting the office equipment. It is preferable to use a cord having a high elastic modulus.

On the land line LL of the belt main body 11, a tooth root width W (intersecting of a land extending line with an arc extension line in the tooth root direction of both tooth side portions 15, 15 of the belt tooth portion 13, which will be described later). A plurality of teeth 13 having a dimension between positions)
(Only one is shown) is formed at a constant tooth pitch PB in the belt length direction, and a land portion located on the land line LL is provided on the bottom surface of the belt body 11 between the tooth portions 13. 12 are provided. This land part 12
May be an arcuate surface, but may be constituted by a substantially flat surface continuously connected to the side surface of the belt tooth portion 13 by root portions 14 and 14 having arcuate surfaces arranged symmetrically with respect to the center line C2 in the tooth width direction. Is desirable.

The pitch PB of the belt teeth 13
Is PB = 1.25 W to 1.5 W with respect to the root width W.
In particular, it is preferable to set PB = 1.37W to 1.47W.

When the belt body 11 is made of rubber as described above, a woven fabric (not shown) made of synthetic fiber is adhered to the surface of the tooth portion 13. The woven fabric is preferably a polyamide fiber, but may be a polyester fiber. Woven fabric is usually R
An adhesive treatment such as an F treatment, an epoxy treatment, and an RFL treatment is performed, and the treatment is performed with a glue rubber. This glue rubber treatment may be performed on both the front and back surfaces of the woven fabric. However, especially in the use of office equipment, the rubber powder does not want to be scattered from the surface of the belt 10, and from the viewpoint of reducing the speed unevenness of the belt 10. Since it is necessary to keep the friction coefficient of the surface of the belt 10 low, it is preferable not to perform the rubber treatment on the side to be the surface of the tooth portion 13.

On the other hand, when the belt body 11 is made of polyurethane, no woven cloth is provided on the surface of the tooth portion 13.
Only the core wire is embedded in the belt body 11.

A feature of the present invention resides in the shape of each of the belt teeth 13 and the pulley teeth 3. That is, as shown in FIG. 1, each belt tooth portion 13 is located symmetrically with respect to the center line C2 (the center line in the belt length direction) of the belt tooth portion 13 on both sides in the belt length direction. A pair of roots 14, 14 each having an arc surface having a predetermined radius r1B continuous with the land 12, and the tooth widths located on the side surfaces of the tooth 13 continuous with the roots 14, 14; A pair of tooth side portions 15, 15 which are provided symmetrically with respect to the direction center line C <b> 2 and have a convex arc surface having an arc radius RB;
A tooth tip portion 16 is located on the root side (inside) of the arc-shaped tooth tip side extension line 15a of the arc surface of 5, 5 and is provided so that both tooth side portions 15, 15 are continuous with each other. The tooth tip portion 16 is formed of a substantially circular arc surface having a predetermined radius r2B and continuing from the tooth side portions 15 and 15 symmetrically with respect to the center line C2 in the tooth width direction. And a flat portion 18 formed of one substantially flat surface provided so as to connect the two arc-shaped surface portions 17 and 17 to each other.

The center point O1 of the arc surface of each tooth side surface portion 15
B is desirably located on or near the pitch line PL of the belt 10. In addition, each tooth side portion 15
RB = 0.7 W to 1.5 W
It is preferable to set RB = 0.8 W to 1.3 W in particular.
W, and more preferably RB = 0.9 W to 1.1 W.

The 0.3 W pressure angle θB at the reference position D which is 0.3 W away from the land line LL in the tooth height direction at the tooth side surface 15 on the side of the belt tooth portion 13 of the toothed belt 10 is θB = 26 to 39 °, desirably θB
= 28-35 °, of which θB = 29-33 ° is preferred, and the optimum value is θB = 31 ° (shown in the example).

Further, as shown in FIG.
The side surface (side surface in the tooth width direction) of the pulley 3 and the side surface (side surface in the tooth groove width direction) of the pulley tooth groove 3 are substantially similar to each other. In the actual transmission state given, the pressure angle on the side surface of the belt tooth portion 13 and the pressure angle on the side surface of the pulley tooth groove portion 3 at each position in the tooth height direction on each side surface of the belt tooth portion 13 and the pulley tooth groove portion 3 are different. The tooth tip 16 of the belt tooth 13 is in contact with the tooth groove bottom 6 of the pulley tooth groove 3 while the land 12 of the belt body 11 is separated from the pulley outer diameter 9 by a predetermined distance. And is in a non-contact state with the pulley outer diameter portion 9.

In this embodiment, the toothed belt 10
When the belt is wound around the pulleys 1 and 2, the land 12 of the belt 10 is wound around the pulley outer diameter 9 in an arc shape, and after the land 12 is wound, the belt teeth 13
Is engaged with the pulley tooth groove portion 3. At this time, the belt land portion 1 is engaged with the belt tooth portion 13 and the pulley tooth groove portion 3 in an engaged state.
In the normal case where the outer diameter portion 2 and the pulley outer diameter portion 9 are in contact with each other, as shown by the imaginary line in FIG. Root arc portion 4 near the tooth root on the front side in the direction
Point O corresponding to (the front end of pulley tooth groove 3 in the running direction)
While rotating about the rotation center (fulcrum).
Bite into. However, in this embodiment, the belt teeth 1
Since the belt land portion 12 and the pulley outer diameter portion 9 do not come into contact with each other when the gear teeth 3 and the pulley tooth groove portion 3 are engaged with each other, when the belt tooth portion 13 bites into the pulley tooth groove portion 3, the belt tooth portion 13 is on the pitch line PL. The center of rotation is the belt land 1
2 and the outer diameter portion 9 of the pulley are in contact with each other,
A point O corresponding to the root arc 4 near the tooth root on the front side in the belt running direction of the pulley tooth groove 3 to be engaged.
Instead, the root arc portion near the root of the rear side of the pulley tooth groove portion 3 adjacent to the target pulley tooth groove portion 3 on the front side in the belt running direction by the distance of the belt land portion 12 from the pulley outer diameter portion 9. 4, the belt tooth portion 13 bites into the pulley tooth groove portion 3 while rotating around the point O '. As a result, compared to the case where the belt land portion 12 and the pulley outer diameter portion 9 are in contact with each other (indicated by a virtual line in FIG. 4), the belt tooth portion 1
3 becomes large, the amount of protrusion of the rotation trajectory on the tooth tip side of the tooth side surface portion 15 becomes small, and it becomes difficult for the tooth side surface portion 5 to interfere with the tooth groove side surface portion 5 of the pulley tooth groove portion 3. It can slide smoothly into the pulley tooth groove 3. For this reason,
It is possible to reduce the fluctuation of the pitch line PL of the belt 10 being pushed up and fluctuated by the reaction force from the pulleys 1 and 2 generated due to the interference, and it is possible to reduce the speed unevenness of the belt 10 due to the meshing interference.

As shown in FIGS. 1 and 2, the belt pitch line PL which is the rotation center O 'is
When the belt pitch line PL is located on the tip side of the arc center point O1B of the tooth side surface portion 15 in the belt tooth portion 15, the tooth pitch is equal to or larger than the arc center point O1B of the tooth side surface portion 15 in the belt tooth portion 13. Compared to the structure located on the original side,
The radius of rotation of the tooth side surface portion 15 of the belt tooth portion 13 on the tooth tip side is reduced, and the rotation trajectory accompanying the rotation of the belt tooth portion 13 is separated from the tooth groove side surface portion 5 of the pulley tooth groove portion 3. As a result, the belt tooth portion 13 slides more smoothly into the pulley tooth groove portion 3, and the speed unevenness of the belt 10 due to the interference between the two can be further reduced.

Generally, the transmission of the load between the pulleys 1 and 2 and the toothed belt 10 is performed in addition to the meshing transmission between the pulley tooth groove 3 and the belt tooth 13, the pulley outer diameter portion 9 and the belt land. This is also achieved by friction transmission between the parts 12, and fluctuations in the rotational speeds of the pulleys 1 and 2 are transmitted to the toothed belt 10 by these two transmission modes, and the toothed belt 1
However, if the belt land portion 12 and the outer diameter portion 9 of the pulley are not in contact with each other, the pulleys 1 and 2 will not move.
Of the modes of load transmission between the belt and the belt 10, the latter friction transmission between the pulley outer diameter portion 9 and the belt land portion 12 is eliminated. Therefore, the rotation speed fluctuation of the pulleys 1 and 2 due to the frictional transmission of the belt land portion 12 is prevented from being transmitted to the belt 10, and the land line LL of the belt 10 and the outside of the pulleys 1 and 2 in the belt tooth portion 13 are prevented. Rotational speed fluctuations of the pulleys 1 and 2 are absorbed by the elasticity of the portion between the pulleys 1 and 2, and the rotation speed fluctuations of the pulleys 1 and 2 are suppressed from being transmitted to the belt 10 by the meshing transmission. Thus, the speed unevenness of the belt 10 can be further reduced.

In the toothed belt 10 in which the belt body 11 is made of polyurethane, when the tooth pitch PB of the belt teeth 13 is 1.5 mm or less, a concave portion provided to separate the core from the land 12 is formed. Since the dimensions are extremely small and the processing of the mold is difficult, the core wire is directly provided on the land portion 12 without providing the concave portion as described above, but this core wire contacts the outer diameter portion 9 of the pulley. To prevent the belt 10 from being damaged, the land 12 of the belt 10
Used without contact. By making the land portion 12 of the belt 10 substantially flat as in this embodiment, the position of the core wire can be stabilized.

Further, as shown in FIG.
When each tooth portion 13 of the drive pulley 1 is meshed with each tooth groove portion 3 of the drive pulley 1 formed of a toothed pulley, the belt tooth portion 13 meshes at a position slightly delayed from the position of the pulley tooth groove portion 3 due to the effect of the applied load torque. As a result, after the side surface of the tooth portion 13 on the rear side in the belt running direction contacts the side surface of the pulley tooth groove portion 3, the belt tooth portion 13 slides into the pulley tooth groove portion 3.

At this time, the span of the belt 10 (the pulley 1
The belt pitch line PL moves up and down in the direction orthogonal to the belt span at the portion not wound around
When the meshing speed unevenness occurs, the vertical movement amount of the pitch line PL is determined by the reaction force generated when the belt tooth portion 13 slides into the pulley tooth groove portion 3 and when the belt 10 is pushed upward by the reaction force. Since it is determined by the component force of the generated belt tension, as the contact position becomes farther from the complete meshing position between the belt tooth portion 13 and the pulley tooth groove portion 3, the component force of the belt tension becomes smaller, and the pushing amount of the pitch line PL becomes larger. In other words, if the contact between the belt teeth 13 and the pulley tooth grooves 3 is early, the speed unevenness increases.

Therefore, in the conventional toothed belt 10,
As shown in FIG. 5B, the 0.3 W pressure angle θB on the side surface of the belt tooth portion 13 is small (θB = 20.8 to 2
5.3 °), the side surface of the belt tooth portion 13 contacts the side surface of the pulley tooth groove portion 3 quickly, whereas in this embodiment,
As shown in FIG. 5A, the 0.3 W pressure angle θB is θB
Since it is ≧ 26 °, which is larger than that of the related art, the contact between the belt tooth portion 13 and the side surface of the pulley tooth groove portion 3 is slowed down, whereby the speed unevenness of the belt 10 can be reduced.

On the other hand, as described above, the amount of movement of the belt span is determined by the reaction force that slides after the side surface of the belt tooth portion 13 comes into contact with the side surface of the pulley tooth groove portion 3 and the component force of the belt tension. If the 3W pressure angle θB is too large, the reaction force generated when the belt tooth portion 13 slides into the pulley tooth groove portion 3 is a vertical direction (a direction orthogonal to the belt span).
Becomes too large to slide easily, and the belt pitch line PL is pushed up.
However, in this embodiment, since the 0.3 W pressure angle θB satisfies θB ≦ 39 ° in this embodiment, the belt teeth 13 smoothly slide into the pulley tooth grooves 3, and the belt 10 An increase in speed unevenness can be suppressed. That is, the optimum range of the 0.3 W pressure angle θB is θB = 2
By setting the angle to 6 to 39 degrees, the uneven speed of the belt 10 can be reduced as much as possible.

In this embodiment, the belt teeth 13
Since the pressure angle at each position in the tooth height direction between the side surface of the pulley and the side surface of the pulley tooth groove portion 3 is substantially equal, as shown in FIG.
The side surface of the belt tooth portion 13 uniformly contacts the side surface of the pulley tooth groove portion 3, and the belt tooth portion 13 smoothly slides into the pulley tooth groove portion 3. For this reason, as shown in FIG. 6B, the side surface of the belt tooth portion 13 is formed by the side surface of the pulley tooth groove portion 3 as in the case where the pressure angle of the pulley tooth groove portion 3 is smaller than the pressure angle of the belt tooth portion 13. As a result, the belt teeth 13 are not brought into contact with the cusp arc portions 4 and are pushed up by the cusp arc portions 4 of the pulley tooth groove portions 3, so that the speed unevenness of the belt 10 can be further suppressed.

The arc radius RB of the tooth side surface portion 15 located on the tooth side surface of the belt tooth portion 13 is equal to the land line LL.
Since RB = 0.7 W to 1.5 W with respect to the above-described tooth width W, the following operation and effect can be obtained. That is, as described above, by increasing the 0.3 W pressure angle θB, the contact of the belt tooth portion 13 with the pulley tooth groove portion 3 when the belt tooth portion 13 bites into the pulley tooth groove portion 3 becomes slow,
This makes it possible to reduce the speed unevenness. However, even if the tooth profile has the same 0.3 W pressure angle θB, the belt tooth portion 13 is determined by the arc radius RB of the tooth side surface portion 15 of the tooth profile.
Is different in ease of slipping into the pulley tooth groove portion 3, which affects speed unevenness. That is, when the belt 10 is engaged with the pulleys 1 and 2, as described above, after the land 12 of the belt 10 is wound around the outer diameter 9 of the pulleys 1 and 2 in an arc shape, the belt teeth 13 are pulled out of the pulley teeth. When the belt tooth portion 13 is engaged with the groove portion 3, the belt tooth portion 13 pivots about a point O ′ on the pitch line PL near the rear root of the pulley tooth groove portion 3 on the front side in the belt running direction with respect to the target pulley tooth groove portion 3. However, if the arc radius RB of the tooth side surface portion 15 is too large (for example, RB = 1.6 W), as shown in FIG. 7B, the tooth tip portion 16 of the belt tooth portion 13 is engaged. When the vicinity slides while interfering with the side surface of the pulley tooth groove portion 3, on the other hand, when the arc radius RB of the tooth side surface portion 15 is too small (for example, RB
= 0.65 W), as shown in FIG. 7C, there is a possibility that the side surface of the belt tooth portion 13 may slip while interfering with the vicinity of the root arc portion 4 of the pulley tooth groove portion 3, and thus the belt tooth portion 13 may be slid.
Of the tooth tip 16 near or on the side surface of the pulley while sliding, the reaction force from the pulleys 1 and 2 generated at the time of biting increases, and the pitch line PL is pushed up to increase the speed unevenness.

However, as in this embodiment, the arc radius RB of the tooth side surface portion 15 of the belt tooth portion 13 is equal to the belt root width W.
7 (RB = 0.7 W to 1.5 W), FIG.
As illustrated in (a), the interference as described above hardly occurs, the vehicle can slide smoothly, and the speed unevenness is reduced. Therefore, if the arc radius RB of the tooth side surface portion 15 is in the range of RB = 0.7 W to 1.5 W with respect to the root width W, it is effective for reducing the speed unevenness of the belt 10.

The tooth pitch PB of the toothed belt 10 is
Since PB is set to 1.25 W to 1.5 W with respect to the tooth width W, the following operation and effect can be obtained. That is, in order to reduce the speed unevenness of the belt 10, it is advantageous that the tooth pitch PB of the belt 10 is as small as possible and the number of pulley teeth is large, since the polygonal effect becomes smaller (closer to a circle). , PB = 1.5 W or less, the speed unevenness is smaller than that of the conventional one. On the other hand, PB =
If less than 1.25W, the outer diameter portion 9 of the pulley becomes too narrow,
There is a problem in the strength and workability of the pulleys 1 and 2. For this reason,
By setting PB = 1.25 W to 1.5 W as in this embodiment, the speed unevenness of the belt 10 can be reduced without incurring the problems of the strength and workability of the pulleys 1 and 2.

Further, the tip 16 of the belt teeth 13
The belt 10 is completely meshed with the pulleys 1 and 2 because the substantially flat plane portion 18 is provided on the other side and the substantially flat plane portion 8 is provided on the tooth groove bottom 6 of the pulley tooth groove 3. In this case, the entire flat portion 18 of the tooth tip portion 16 of the belt tooth portion 13 is received in a large area by the flat portion 8 of the tooth groove bottom portion 6 of the pulley tooth groove portion 3, and the center line position of the belt 10 at the time of complete meshing. (Pitch line PL) can be further stabilized, and the speed unevenness of the belt 10 can be further reduced.

As described above, the speed unevenness of the belt 10 is reduced as much as possible, so that the printing accuracy and the image quality of office equipment can be improved.

Since the tooth groove bottom 6 of each pulley tooth groove 3 of the pulleys 1 and 2 is substantially flat, the tooth groove bottom 6 of the pulley tooth groove 3 is substantially the same as the tooth tip 16 of the belt tooth 13. It can have a planar shape. In the first embodiment, only the tooth groove bottom 6 of the pulley tooth groove 3 may be formed by an arc surface having a center in the pulley center direction.

(Embodiment 2) FIGS. 8 and 9 show Embodiment 2 of the present invention. In the following embodiments, the same parts as those in FIGS. In this embodiment, the shape of the belt teeth 13 is changed.

That is, in this embodiment, as shown in FIG. 9, the pulley tooth groove portions 3 of the pulleys 1 and 2 are arranged symmetrically with respect to the center line C1 in the tooth groove width direction as shown in FIG. Tooth groove arc portions 4 and 4 formed of circular arc surfaces, and tooth groove side surface portions formed of concave circular arc surfaces provided symmetrically with respect to the center line C1 in the tooth groove width direction continuously to the crest arc portions 4 and 4. 5, 5 and a tooth groove bottom portion 6 composed of arcuate surface portions 7, 7 and a flat surface portion 8 provided so as to connect the two tooth groove side surface portions 5, 5 to each other.

On the other hand, as shown in FIGS. 8 and 9, each belt tooth portion 13 of the toothed belt 10 is different from that of the first embodiment in that the belt tooth portion 13 is provided on both sides in the belt length direction. A pair of roots 14, 14 each having an arc surface having a predetermined radius r1B and located symmetrically with respect to the center line C2 and continuing to the land 12, and the tooth 1 continuing to the roots 14, 14.
1. A convex arc surface having an arc radius RB provided on three side surfaces and symmetrically provided with respect to the center line C2 in the tooth width direction.
A pair of tooth side portions 15, 15 and both tooth side portions 15, 15
Are provided so as to be continuous with each other, and have an arc radius r having a center point O2B on the center line C2 in the face width direction of the belt tooth portion 13.
And a tooth tip 16 formed of one arc surface of the TB.

As in the first embodiment, the 0.3 W pressure angle θB at the reference position D of the tooth side surface portion 15 on the side surface of each belt tooth portion 13 is θB = 26 to 39 °, preferably θB = 26 to 39 °. = 28-35 °, of which θB = 29-3
3 ° is preferable, and the optimal value is θB = 31 ° (shown in the illustrated example).

Further, the side surface of the belt tooth portion 13 and the side surface of the pulley tooth groove portion 3 are substantially similar to each other, and in a transmission state in which the belt 10 is wound around the pulleys 1 and 2 and tension is applied to the belt 10, the belt tooth portion is formed. The pressure angle of the side surface of the belt tooth portion 13 and the pressure angle of the side surface of the pulley tooth groove portion 3 at each position in the tooth height direction of each side surface of the tooth groove portion 3 and the pulley tooth space 3 are substantially equal to each other.
In addition, the tooth tip 16 of the belt tooth 13 and the tooth groove bottom 6 of the pulley tooth groove 3 come into contact with each other, and the land 12 of the belt main body 11 is separated from the pulley outer diameter 9 and both are in a non-contact state. Other configurations are the same as those of the first embodiment.

Therefore, also in this embodiment, the same operation and effect as in the first embodiment can be obtained. In addition, since the tooth tip 16 of each belt tooth 13 is formed of one circular surface, the contact of the belt tooth 13 with the pulley tooth groove 3 as shown by the solid line in FIG. The advantage is that the speed unevenness of the belt 10 can be more effectively reduced as compared with the structure of the first embodiment (shown by the phantom line in FIG. 10) in which the speed can be further reduced and the 0.3 W pressure angle θB is simply increased. is there.

(Embodiment 3) FIG. 11 shows Embodiment 3. In this embodiment, each of the belt teeth 13 of the toothed belt 10 has one arc at its tip end, as in Embodiment 2 described above. A tooth tip 16 formed of a surface is provided so as to connect both tooth side portions 15 on both sides in the belt length direction.

On the other hand, the tooth groove bottom portion 6 of each pulley tooth groove portion 3 of the pulleys 1 and 2 has a center point O2P on the tooth groove width direction center line C1 and has an arc radius of the tooth tip portion 16 of the belt tooth portion 13. It is composed of one arc surface having an arc radius rTP slightly larger than rTB. Other configurations are the same as those of the second embodiment.

In the case of this embodiment, the tooth groove bottom 6 of each pulley tooth groove 3 has a radius rTP (> rTB) slightly larger than the radius rTB of the circular arc surface of the tooth tip 16 of each belt tooth 13. When the belt 10 bites into the pulleys 1 and 2, the side surface of the belt tooth portion 13 slides more smoothly into the side surface of the pulley tooth groove portion 3. In addition, the tooth tip 16 of the belt tooth 13 is an arc surface continuously provided with the tooth side surface 15, and the tooth groove bottom 6 of the pulley tooth groove 3 is provided continuously with the tooth groove side 5. Until the moment when the belt 10 and the pulleys 1 and 2 are completely meshed, not only the side surfaces of the belt teeth 13 but also the tooth tips 1
6 smoothly slides into the pulley groove bottom 6. By these actions, the vertical amount of the pitch line PL hardly occurs, and the speed unevenness of the belt 10 can be extremely reduced.

The tooth groove bottom 6 of the pulley tooth groove 3 is formed of an arc surface having a radius rTP slightly larger than the arc radius rTB of the tooth tip 16 of the belt tooth portion 13. Almost the entire arc surface of the tooth tip 16 of the tooth portion 13 can be received over a large area of the arc surface of the tooth groove bottom portion 6 in the pulley tooth groove portion 3, and the center line position of the belt 10 at the time of complete meshing can be stabilized. In addition, the speed unevenness of the belt 10 can be reduced.

(Other Embodiments) In each of the above embodiments,
Although the toothed belt 10 and the transmission A mounted on office equipment such as a printer and a copier have been described, the present invention can be applied to toothed belts and transmissions other than office equipment. Needless to say.

[0071]

Next, a specific embodiment will be described. Manufacture a transmission consisting of a belt and a pulley,
A bench test for measuring the belt speed unevenness with a measuring device was performed. That is, as an example of the present invention, a toothed belt and a toothed pulley were manufactured with the configuration of Embodiment 1 shown in FIGS. 1 and 2. Specifically, the 0.3 W pressure angle of the belt is 29.
At 2 °, the 0.3W pressure angle of the pulley is also the same, 29.2 °, and the toothed belt in which the land between the belt teeth of the belt body and the outer diameter of the pulley are in non-contact with the pulley when meshed with the pulley. , And a toothed belt were manufactured (Example of the present invention).

On the other hand, as a conventional example, the.
The 3W pressure angle is 25.3 °, the 0.3W pressure angle of the pulley is the same 25.3 °, and the land between the belt teeth of the belt body and the outer diameter of the pulley are in contact with the pulley while meshing with the pulley. , And a toothed belt.

The respective dimensions are as shown in Table 1 below. In addition, the dimension value is the pitch of the belt tooth portion (2.117 m
m) is represented by an index with “1.0”.

[0074]

[Table 1]

Specifically, the toothed belt has a tooth pitch of 2.1.
It is made of rubber having 17 mm arc-shaped teeth, and the rubber is chloroprene rubber having a hardness of 70 °, and the core wire is made of glass fiber having a diameter of 0.3 mm. The woven fabric was made of polyamide wooly yarn, and was subjected to an RF treatment and a rubber paste treatment for only the back surface.

The speed unevenness of these toothed belts during actual running was measured by a belt speed unevenness measuring device shown in FIG. This measuring apparatus includes a drive and driven pulleys 1 and 2 composed of a toothed pulley around which a test toothed belt 10 is wound, and applies a belt tension by a static load DW to the driven pulley 2 and applies a driven pulley. The drive pulley 1 is rotated in the direction of the arrow in the figure in a state where no load is applied to the portion 2, and a portion d 1 = 10 mm away from the axis of the drive pulley 1 in the loose side span of the belt 10 at that time is moved from that portion. The laser beam 43a is applied to the side of the belt from the probe 43 at a position d2 = 100 ± 2 mm away from the belt.
4, the speed unevenness of the belt 40 is measured, the frequency of the speed unevenness is analyzed by the FFT 45, taken into the personal computer 46, and the data is printed by the printer 47. FIG. 13 shows measurement data of the speed unevenness measuring device, and FIG. 14 shows data obtained by analyzing the frequency of the speed unevenness of the belt 10 (FIG. 14A).
FIG. 14B shows a second example of the present invention, and FIG. 14B shows a conventional example. Looking at the speed fluctuations at the respective meshing frequencies of the present invention example and the conventional example, the present invention example is 0.03%, whereas the conventional example is 0.13%. It was confirmed that the configuration significantly reduced the speed fluctuation of the belt.

[0077]

As described above, according to the first aspect of the present invention, as a toothed belt transmission which is a combination of a toothed belt and a toothed pulley, each tooth portion of the toothed belt has a substantially arcuate surface. A pair of tooth roots, a pair of tooth side surfaces composed of a substantially arcuate surface having a convex shape, and a tooth tip located on the tooth root side with respect to the tooth tip side extension of the arc surface of the tooth side surface. In this configuration, the tooth tip portion is formed of an arc surface portion formed of a substantially arc surface provided so as to be continuous with the arc surface of both tooth side portions, and one of a substantially flat surface provided to connect the two arc surface portions. On the other hand, each pulley tooth groove portion of the toothed pulley is formed by a pair of tooth crest arc portions formed by an arc surface and a pair of tooth groove side surfaces formed by a concave arc surface. The belt is wound around the pulleys and tension is applied to the belt. In transmission state, the land portion and the pulley outside diameter portion between the belt teeth of the belt body is set to be a non-contact state. According to a second aspect of the present invention, in the same configuration as the first aspect, the tooth tip of the belt tooth portion is continuous with the arc surfaces of both tooth side portions and has a center point on the center line in the tooth width direction. It consisted of one arc surface. Therefore, according to these inventions, when the belt tooth portion bites into the pulley tooth groove portion, the belt tooth portion corresponds to the root apex arc portion near the rear root of the pulley tooth groove portion adjacent to the target pulley tooth groove portion on the front side in the belt running direction. The rotation locus of the tooth tip side of the tooth side surface of the belt tooth portion is separated from the tooth groove side surface portion of the pulley tooth groove portion so as to bite into the pulley tooth groove portion while rotating about a point on the belt pitch line to be rotated as a rotation center. And make it less likely to interfere with it. In addition, in the mode of load transmission between the pulley and the belt, the frictional transmission between the outer diameter portion of the pulley and the belt land portion is removed to prevent transmission of the rotational speed fluctuation of the pulley to the belt due to the frictional transmission of the belt land portion. In addition, the elasticity of the portion between the belt land line and the pulley outer diameter line of the belt tooth portion absorbs the fluctuation of the rotation speed of the pulley, and the transmission of the fluctuation of the rotation speed of the pulley to the belt can be suppressed. Therefore, the speed unevenness of the belt can be further reduced by a synergistic effect of these.

According to the third aspect of the present invention, the root width on the land line of the toothed belt is W, and the reference is 0.3 W away from the land line in the tooth height direction on the tooth side surface of the belt tooth portion. 0.3W pressure angle at position 26-3
By setting the angle to 9 °, the side surface of the belt tooth portion comes into slow contact with the side surface of the pulley tooth groove portion when the belt tooth portion meshes with the pulley tooth groove portion, and the reaction force generated when the belt tooth portion slides into the pulley tooth groove portion. By reducing the vertical component of
The toothed belt can be easily slipped on, and the speed unevenness of the toothed belt can be further reduced.

According to the fourth aspect of the present invention, the land portion of the toothed belt is formed to be substantially flat, so that the first or second aspect of the present invention is provided.
The effect of the invention of (1) is effectively obtained.

According to the fifth aspect of the present invention, the tooth side surface of the belt tooth portion is substantially similar to the tooth groove side surface portion of the pulley tooth groove portion, and the belt is wound around the pulley and is in a transmission state in which tension is applied to the belt. By making the pressure angle on the side surface of the belt tooth portion and the pressure angle on the side surface of the pulley tooth groove portion at each position in the tooth height direction on each side surface of the belt tooth portion and the pulley tooth groove portion substantially equal, the belt tooth portion in the transmission state The belt tooth side evenly contacts the pulley tooth groove side when biting into the pulley tooth groove part, and the belt tooth part smoothly slides into the pulley tooth groove part. Speed unevenness can be further reduced.

According to the sixth aspect of the present invention, there is provided an office machine equipped with the toothed belt transmission and having a carriage attached to the toothed belt.
The printing speed and image quality can be improved by reducing the speed fluctuation of the carriage of the office equipment.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a tooth portion of a toothed belt according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a state in which the teeth of the toothed belt of the toothed belt transmission according to the first embodiment are engaged with the toothed pulley.

FIG. 3 is a front view schematically showing the entire configuration of the toothed belt transmission.

FIG. 4 is a diagram illustrating a difference due to a difference in a rotation center when a belt tooth portion meshes with a pulley tooth groove portion while rotating.

FIG. 5 is an explanatory view schematically showing a state in which a tooth portion of a toothed belt meshes with a tooth groove portion of a toothed pulley.

FIG. 6 is a diagram corresponding to FIG. 5 showing a meshing state according to a difference in pressure angle between a tooth side surface of the toothed belt and a tooth groove side surface of the toothed pulley.

FIG. 7 is a diagram corresponding to FIG. 5, showing a meshing state according to a magnitude of an arc radius of a tooth side surface portion of a belt tooth portion.

FIG. 8 is a view corresponding to FIG. 1 showing a tooth portion of a toothed belt according to a second embodiment of the present invention.

FIG. 9 is a diagram corresponding to FIG. 2, showing the second embodiment.

FIG. 10 is a diagram corresponding to FIG. 5, schematically showing a state in which the teeth of the toothed belt mesh with the tooth grooves of the toothed pulley in the second embodiment.

FIG. 11 is a diagram corresponding to FIG. 2, showing the third embodiment.

FIG. 12 is a view showing a belt speed unevenness measuring device.

FIG. 13 is a diagram showing measurement data of a belt speed unevenness measuring device.

FIG. 14 is a diagram showing data obtained by analyzing the frequency of the uneven speed of the belt.

FIG. 15 is a diagram corresponding to FIG. 2, showing a state where the teeth of a conventional toothed belt mesh with a toothed pulley.

[Explanation of symbols]

 A Toothed belt transmission 1, 2 Pulley 3 Pulley tooth groove 4 Teeth arc part 5 Tooth groove side part 6 Tooth groove bottom part 7 Arc surface part 8 Flat part 9 Pulley outer diameter part C1 Tooth groove width direction center line O2P Center point rTP Arc radius 10 Toothed belt 11 Belt body 12 Land portion 13 Belt tooth portion 14 Root portion 15 Tooth side portion 16 Tooth tip portion 17 Arc surface portion 18 Flat surface portion D Reference position PL Pitch line LL Land line C2 Centerline in width direction O2B Center point rTB Arc radius θB 0.3W Pressure angle W Root width O 'Rotation center

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ryuichi Kido 3-2-15 Meiwadori, Hyogo-ku, Kobe-shi, Hyogo F-term (reference) in Bando Chemical Co., Ltd. 2C480 CA01 CA09 DA04 DA16 3J031 AA01 BB05 CA04 3J049 AA03 BF02 BH04 CA10

Claims (6)

[Claims] A toothed belt including a belt body having a tensile member embedded on a pitch line, a plurality of belt teeth provided at a constant pitch on a land line of the belt body, A toothed belt transmission comprising a combination of a toothed pulley having a plurality of pulley tooth grooves provided at a constant pitch on a diameter line, wherein each tooth of the toothed belt has a center in a tooth width direction. A root portion composed of a substantially arcuate surface symmetrically arranged with respect to a line, and a substantially convex shape provided on the side surface of the tooth portion continuously to the root portion and provided symmetrically with respect to the center line in the tooth width direction. A tooth side surface portion having an arcuate surface, and a substantially arcuate surface which is located closer to the root of a tooth tip side extension line of the arcuate surface of the both tooth side portions and is continuous with the arcuate surface of both tooth side portions. And an approximately plane provided so as to connect the two arc surfaces. The toothed pulley of the toothed pulley has a substantially circular arc surface symmetrically arranged with respect to a center line in the tooth groove width direction. A top arc portion, a tooth groove side surface portion consisting of a substantially concave arcuate surface provided symmetrically with respect to the tooth groove width direction center line continuously with the tooth root arc portion, and the two tooth groove side portions are connected to each other. In the transmission state in which the pulley is wound around the belt and tension is applied to the belt, the land portion between the belt teeth of the belt body and the outer diameter portion of the pulley are formed. A toothed belt transmission in a non-contact state. 2. A toothed belt including a belt body having a tensile member embedded on a pitch line, a plurality of belt teeth provided at a constant pitch on a land line of the belt body, A toothed belt transmission comprising a combination of a toothed pulley having a plurality of pulley tooth grooves provided at a constant pitch on a diameter line, wherein each tooth of the toothed belt has a center in a tooth width direction. A root portion composed of a substantially arcuate surface symmetrically arranged with respect to a line, and a substantially convex shape provided on the side surface of the tooth portion continuously to the root portion and provided symmetrically with respect to the center line in the tooth width direction. A tooth side surface portion formed of an arc surface, and located on the root side of the tip side extension line of the arc surface of the both tooth side portions, continuous with the arc surface of both tooth side portions, and centered on the center line in the tooth width direction. While the tooth tip is composed of a single arcuate surface having points. Each pulley tooth groove portion of the pulley has a root arc portion having a substantially circular arc surface symmetrically arranged with respect to the tooth groove width direction center line, and a symmetrical with respect to the tooth groove width direction center line continuously with the tooth root arc portion. And a tooth groove bottom portion provided to connect the two tooth groove side portions to each other, and a pulley is wound around the belt to form a belt. Wherein the land between the belt teeth of the belt body and the outer diameter of the pulley are not in contact with each other in a transmission state in which tension is applied to the belt. 3. The toothed belt transmission according to claim 1, wherein, when a root width of the toothed belt on the land line is W, a tooth height from the land line on a tooth side surface portion of the belt tooth portion. Pressure angle at the reference position 0.3W away from the
A toothed belt transmission having an angle of 39 °. 4. The toothed belt transmission according to claim 1, wherein a land portion of the toothed belt is substantially flat. 5. The toothed belt transmission according to claim 1, wherein the tooth side surface of the toothed belt and the tooth groove side surface of the toothed pulley of the toothed pulley are substantially similar. In the transmission state in which the pulley is wound around the belt and tension is applied to the belt, the pressure angle at each position in the tooth height direction of the tooth side surface portion of the belt tooth portion and the tooth groove side surface portion of the pulley tooth groove portion is reduced. A toothed belt transmission having substantially the same configuration. 6. An office equipment, comprising the toothed belt transmission according to claim 1, wherein a carriage is mounted on the toothed belt.