JPH02221735A - Toothed belt and driver thereof - Google Patents

Abstract

PURPOSE:To reduce a noise as well as to enable sufficient power transmission by installing at least more than two projections in a belt tooth part while installing a corner part in a boundary part between a power transmission area and this belt tooth part. CONSTITUTION:When first a belt tooth part 3 is fitted in a pulley groove part 26, two projections 15 of a belt tooth tip part 9 are made contact with each other continuously or simultaneously without interfering with a pulley groove wall 29 and deformed in contact under pressure. Successively a corner part being situated in a boundary part between a power transmission area 8 and the belt tooth tip part 9 closely comes into contact with the pulley groove wall 29. Accordingly, when the belt tooth part 3 is fitted in the pulley groove part 26, a contact point between the belt tooth part 3 and the pulley groove part 26, namely, the projection 15 and the corner part 14 are made contact with each other continuously and compressively deformed, thus the power transmission area 8 closely comes into contact with the pulley groove wall 29. Consequently, impact energy between the belt tooth part 3 and the pulley groove part 26 is absorbed, thus a impact noise is reduced.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a toothed belt and a drive device using the same, and more particularly, to a toothed belt that achieves smooth engagement with a pulley and that can be used for high-load transmission. The present invention relates to a toothed belt and a toothed belt drive device that reduce abnormal noise or noise during meshing between the toothed belt and the pulley.

(Prior art) Toothed belts are capable of reliable transmission without slipping, and compared to other reliable transmission systems such as gears and chains,
Demand for this technology has been increasing in recent years because it eliminates the need for refueling and has advantages such as low noise. As stipulated in RMAIp-24 (1978) as a generally widely used drive device consisting of a combination of a toothed belt and a pulley, a belt tooth section with an inverted trapezoid cross section and a groove group of similar shapes to the tooth section are provided. There is a transmission system that meshes with a pulley provided on the circumference.

In addition, the teeth of the toothed belt constituting this type of transmission system disclosed in U.S. Pat. No. 3,756,091 and U.S. Pat. It is composed of round teeth consisting of a pair of intersecting circular arcs each having the same radius of curvature. Correspondingly, the pulley also has a pulley groove formed from one circular arc on its circumferential surface, and this toothed belt When engaged with the pulley, the belt teeth contact or compressively engage the bottom of the groove of the pulley, which is intended to reduce wear on the belt groove surface.

Also, U.S. Patent No. 4,108,011 (Japanese Patent Publication No. 57
-51589), a toothed belt with round teeth consisting of a pair of circular arcs having a center point on the pitch line of the belt, and grooves similar to the belt teeth are provided on the circumferential surface of the pulley. A toothed belt drive device is disclosed that includes a combination of pulleys, in which the toothed belt is compressively engaged with the pulleys to improve noise prevention.

Furthermore, as a drive device that compressively engages a toothed belt with a pulley to reduce noise when the belt is driven, the Japanese Patent Publication No. 59-
It is disclosed in Japanese Patent Application Laid-open No. 1896, Japanese Patent Application Laid-Open No. 58-160649, Japanese Patent Application Laid-open No. 160659-1982, and Japanese Utility Model Publication No. 32186-1986.

As described above, the majority of today's toothed belts are those having teeth with an inverted trapezoidal cross section, or toothed belts having round teeth consisting of a pair of fixed circular arc surfaces.

(Problems to be Solved by the Invention) As described above, in order to prevent noise in today's round toothed belts and their drive devices, the height of the belt tooth portion is made larger than the depth of the pulley groove portion, and the belt tooth portion is first placed on the bottom surface of the pulley groove portion. This was to prevent the knocking noise between the belt groove surface and the pulley tooth surface. However, when the belt tooth part fits into the pulley groove part, the tip of the belt tooth part contacts the pulley groove part at once, so there is a problem that compressive deformation is difficult to occur here and sufficient collision energy cannot be absorbed. There was a noise caused by the sound.

Furthermore, when the belt separates from the pulley, the pulley tooth tips may rotate while rubbing against the belt teeth, causing noise.

In particular, during high-load transmission, the belt teeth are strongly pressed against the side walls of the pulley groove, and when the belt separates from the pulley, the pulley tooth tip rotates while interfering with the tooth tip region rather than the belt tooth root. This not only caused noise but also caused large stress concentrations at the root of the belt teeth, making it more likely to crack. Therefore, simply compressing the belt teeth into pulley grooves is not a sufficient noise prevention measure, and further improvements are needed for high-load transmission applications.

The present invention aims to solve these problems by smoothly engaging the belt teeth with the pulley grooves, especially under high-load transmission conditions, and by correspondingly changing the contact points between the belt teeth and the pulley. It reduces collision noise between the belt teeth and the pulley groove, and when the belt comes off the pulley, the belt teeth run without being interfered with by the pulley tooth tips, reducing noise and efficiently transmitting power. An object of the present invention is to provide a toothed belt and a toothed belt drive device that can perform the following steps.

(Means for Solving the Problems) That is, the toothed belt according to the present invention has a tensile member embedded in the pitch line of the belt body, has teeth portions at a constant pitch in the belt body, and the toothed belt portions have teeth portions arranged at a constant pitch. The belt teeth are bilaterally symmetrical with respect to the center line and consist of a belt tooth root, a power transmission region, and a belt tooth tip, and the belt tooth tip is provided with at least two protrusions, and the power transmission region and the belt A corner portion is provided at the boundary portion of the tooth tip.

Here, the belt tooth portion can have various forms, one of which is that the power transmission area is formed by an arc with a radius of curvature RA, and the belt tooth tip also has a radius of curvature RB. It is formed by a circular arc, and RA is larger than RB.

Moreover, as another aspect, as described in claim 3, the center points of the circular arcs forming the power transmission region and the belt tooth tips are both located within the belt body.

Further, as described in claim 4, the power transmission area of the belt tooth portion is 10 to 10 times higher than the belt tooth portion height from the belt land line.
It is an area whose starting point is a point 25% away from the line and whose end point is a point 50 to 80% away from the belt tooth height from the line, and the straight line connecting the starting point S and the ending point F is the center line of the belt tooth portion. The angle is 9 to 20 degrees.

Further, as described in claim 5, the corner portion located at the boundary between the power transmission region and the belt tooth tip portion coincides with the end point F that is 50 to 80% apart from the belt land line by the height of the belt tooth portion.

Furthermore, in claim 6 relating to a drive device for a toothed belt, a tensile member is embedded on the pitch line of the belt body, teeth are provided at a constant pitch in the belt body, and the side wall of the belt tooth is located at the tip of the belt tooth. A toothed belt consisting of a power transmission region, a belt tooth tip, and a toothed belt having at least two protrusions on the belt tooth tip and a corner portion at the boundary between the power transmission region and the belt tooth tip. The toothed pulley is curved, and when the toothed belt and the pulley engage, the protrusion provided at the tip of the belt tooth and the corner portion are successively brought into contact with the wall surface of the pulley groove.

Further, in claim 7, in a state where at least one side surface of the belt tooth portion is in contact with the pulley groove wall surface, backlash occurs between the bell tooth root portion and the pulley groove wall, and between the belt tooth tip portion and the pulley groove wall. may be provided, and the power transmission area of the belt teeth may be brought into contact with the pulley groove wall within that area.

(Function) The toothed belt of the present invention having the above configuration has at least two or more protrusions on the bell tooth tip and a corner portion on the boundary between the belt tooth tip and the power transmission area. When the belt meshes with the pulley, the protrusions and corner portions successively contact the side wall of the pulley groove, and the contact point between the belt teeth and the pulley changes sequentially, thereby reducing the collision energy between the belt teeth and the pulley. is absorbed and the collision sound is alleviated.

In addition, by increasing the rising angle (pressure angle) of the power transmission area of the belt teeth and specifying that area, it is possible to efficiently transmit large power to the belt teeth. Increases grip strength and prevents belt jumping.

Furthermore, in the drive device, it is possible to similarly reduce the collision sound and noise between the belt teeth and the pulley groove, and when the belt and the pulley mesh, the noise between the belt tooth root and the pulley groove wall and the belt tooth tip can be reduced. If backlash exists between the pulley groove wall and the pulley groove wall, the belt will mesh without interfering with the pulley groove wall, and even when the belt comes off the pulley, the pulley tooth tip will scrape the surface of the belt tooth. Rotates smoothly without any problems.

(Example) Hereinafter, further examples of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view of the toothed part of the toothed belt according to the present invention, and FIG.
The figure is a front view of the teeth of another toothed belt, and Figure 3 is a front view of the teeth of another toothed belt.
It is a front view of the groove part of the pulley which meshes with the toothed belt shown in a figure.

As shown in FIG. 1, the toothed belt (1) used in the present invention has a belt main body (2) made of a rubber-like elastic material such as rubber or synthetic resin, and the back surface of the belt main body (2) is Belt teeth (3) and belt grooves (4) are formed alternately at a constant pitch in the direction, and on the pitch line (5) of the belt body (2), a low elongation material such as glass fiber or aramid fiber is formed. A strong lobe-shaped tensile material is embedded. The back side of the belt (1), which is constituted by the belt teeth (3) and the belt grooves (4), is entirely continuously covered with a cover canvas.

This belt tooth part (3) is symmetrical with respect to the center line (1) of the belt tooth part, and the side wall of the belt tooth part is the belt root part (7) extending from the belt land line (6), and the intermediate part of the side wall. It is composed of a series of areas including a power transmission area (8) from a starting point S located at , which will be described later, to an ending point F, and a belt tooth tip (9).

The belt dedendum (7) is formed by a constant circular arc of radius Rc with the center point (10) located within the belt groove (4), and the power transmission area (8) is located on the pitch line (5). The center point (1) located above the belt groove (4)
1), and the rising angle of the area is large as will be described later.

In addition, the belt tooth tip (9) has a radius RBtr smaller than the radius of curvature R0, and the center point (12) is set at the pitch line (5
) is formed by a circular arc located above the belt teeth (3), and the boundary (13) with the power transmission area (8) is a corner (14). Therefore, the belt tooth tip (9) is located considerably inside the extension line of the circular arc of the power transmission region (8), and a corner portion (14) appears at the boundary portion (13).

Further, the belt tooth tip (9) is provided with at least two arc-shaped protrusions (15) protruding from the surface thereof,
It comes into contact with the pulley groove and is easily compressed and deformed.

The power transmission region (8) is located at the boundary (13) between the starting point S, which is the boundary with the belt tooth root (7), and the belt tooth tip (9).
, that is, the area leading to the end point F, but this boundary part (13)
is located at a distance of about 50 to 80% of the belt tooth height HB from the belt land line (6).

On the other hand, the starting point S is located at a distance of about 10 to 25% of the height HB of the belt teeth from the belt land line. This area (8) comes into contact with the pulley groove wall and efficiently transmits power, and also becomes a place that receives large compressive strain.

In addition, when the boundary part (13) exceeds 80% of the belt tooth height and moves away from the belt land line, the belt tooth root part receives a large stress due to the moment relationship.
Teeth root cracks are more likely to occur.

Further, the angle a between the straight line (16) connecting the starting point S and the ending point F of the power transmission region (8) and the belt tooth center line (1), that is, the pressure angle, is 9 to 20 degrees, preferably 13 to 18 degrees. can be,
When this pressure angle exceeds 20°, the force pushing up the belt teeth increases, and the gripping force of the belt teeth decreases.
Belt jumping is more likely to occur. On the other hand, when the pressure direction is less than 9°, the component force in the power transmission direction applied to the belt teeth increases, and the transmission efficiency increases, but on the other hand,
Due to the action of a large moment on the belt dedendum (7), cracks are likely to occur in the belt dedendum (7).

In addition, the toothed belt (1) shown in Fig. 2 has belt teeth (3
) The shapes of the power transmission area (8) and the belt tooth tip (9) are different from the belt tooth part shown in Figure 1, and the power transmission area (8) is located between the pitch line (5) and the belt body surface. (1
7) and is formed from an arc with a radius of curvature RA having a center point (11) above the belt groove (4), and the belt tooth tip (9) is also located between the belt body surface (17).
) and the belt pitch line (5), and is formed from a circular arc with a radius of curvature RB having a center point above the belt teeth (3). Therefore, in this case as well, the belt tooth tip (
9) is also located away from the extension of the power transmission area (8), and there is a clear corner (14) at this boundary.
) appears.

Furthermore, the belt tooth tip (9) has two arc-shaped protrusions (15) protruding from the surface at its tip. The height h to the tip is about 5 to 10% of the belt tooth height HB.

Therefore, in the belt according to the present invention, the position of the center point of the circular arc of the power transmission region (8) and the belt tooth tip (9) is not particularly limited, and there is a corner portion (14) at the boundary between these regions.
) should appear. The corner portion (14), together with the protrusion (15) provided on the belt tooth tip (9), is a portion that successively and continuously contacts the pulley groove, so it is necessary to make it appear to some extent. Therefore, the power transmission region (8) may be a linear plane, a constant ellipse, etc. instead of a circular arc.

On the other hand, as an example of a pulley that meshes with the toothed belt (1), as shown in FIG. (23) and the tooth tip surface portion (2) formed by a curved line.
4) and a concave shape that is a combination of a circular arc with a radius of curvature r, 1, which is located on the pulley groove center line (25) and has a center point (27) within the pulley groove (26), and a straight line portion (28) connected to the circular arc. It is constituted by a pulley groove wall (29).

The manner in which the toothed belt (1) shown in FIG. 1 meshes with the pulley (20) shown in FIG. 8 is shown in FIGS. 4 to 6.
As shown in the model in the figure, when the belt tooth (3) first fits into the pulley groove (26), the two protrusions (15) on the belt tooth tip are continuous without interfering with the pulley groove wall (29). They contact each other or at the same time and are pressed and deformed. Subsequently, after the corner portion (14) located at the boundary between the power transmission region (8) and the belt tooth tip (7) comes into contact with the pulley groove wall (29), the power transmission region (8) contacts the pulley groove wall (29). close to the wall (29),
Backlash exists between the belt tooth root (7) and the pulley tooth tip (23) and between the belt tooth tip (9) and the pulley groove wall (29), causing the belt tooth ( 3), the engagement with the pulley groove portion (26) is completed.

Therefore, when the belt teeth (3) fit into the pulley groove (26), the contact points between the belt teeth and the pulley, that is, the projections (15) and the corner portions (14) successively abut and compress. The power transmission area (8) is deformed and the pulley groove wall (29)
As a result, the collision energy between the belt teeth (3) and the pulley groove (26) is absorbed, and the collision noise is alleviated. Furthermore, after the meshing is completed, the belt tooth base (
7) and the pulley tooth tip (23) and the belt tooth tip (9)
Since there is backlash between the pulley groove wall (29) and the pulley groove wall (29), the belt tooth (3) is easily removed from the pulley in order for the pulley tooth tip (23) to rotate smoothly without rubbing the side wall of the belt tooth. Exit to.

(Effect) As described above, the toothed belt according to claim 1 has at least two protrusions on the belt tooth tip and a corner portion at the boundary between the belt tooth tip and the power transmission area. When the belt meshes with the pulley, the projections and corner portions successively contact the pulley groove wall surface and are compressed and deformed, changing the contact point between the belt teeth and the pulley. It has the effect of absorbing collision energy and reducing collision noise.

Furthermore, in the belt tooth portions according to claims 2 and 8, the corner portion appears more clearly at the boundary between the power transmission region and the belt tooth tip, so that the contact point between the belt tooth portion and the pulley is clear. This has the effect of further alleviating the collision noise between the belt teeth and the pulley groove.

Further, the power transmission area of the belt teeth described in claim 4 is within a limited range, and in claim 5, the rising angle of the power transmission area is limited, so that the belt teeth can be efficiently transmitted. Can transmit large amounts of power,
Furthermore, the gripping force of the belt teeth is increased, which has the effect of preventing the belt from jumping.

Furthermore, the drive device according to the sixth aspect has the effect of alleviating the collision sound and noise between the belt teeth and the pulley groove, and efficiently transmitting a large amount of power.

Further, in claim 7, when the belt and the pulley are statically engaged, there is a relationship in which backlash exists between the belt tooth root and the pulley tooth tip and between the belt tooth tip and the pulley groove wall. First, when the belt teeth mesh with the pulley grooves, the belt teeth mesh without interference, and when the belt teeth come off the pulley, the pulley tooth tips do not rub against the side walls of the belt teeth, and the teeth mesh smoothly. Since it rotates, the noise factor of 4 degrees when driven by a belt is excluded.

[Brief explanation of the drawing]

FIG. 1 is a front view of the teeth of a toothed belt according to the present invention, FIG. 2 is a front view of the teeth of another toothed belt according to the present invention, and FIG. 3 is a pulley that can be used in the toothed belt of the present invention. front view of the groove,
4, 5, and 6 are diagrams showing the meshing state of the toothed belt shown in FIG. 1 and the pulley shown in FIG. 3, respectively. (1)...Toothed belt (2)...Belt body (3)...Belt teeth (4)...Belt groove (5)...Pitch line (6)...Belt land line (7)・Belt root (8) ・Power transmission area (9) ・Belt tooth tip (13) ・Boundary portion (14) ・Corner portion (15) ・Protrusion (20) ・(21), (23), (26), (29), Pulley, Pulley teeth, Pulley tooth tip, Pulley groove, Pulley groove wall

Claims (1)

[Claims] 1. A tensile member is embedded on the pitch line of the belt body, and the belt body has teeth at a constant pitch, and the belt teeth are located at the root of the belt, the power transmission area, and the belt teeth. What is claimed is: 1. A toothed belt comprising a tip portion, the belt tooth tip portion having at least two or more protrusions, and a corner portion provided at a boundary between the power transmission region and the belt tooth tip portion. 2. The toothed belt according to claim 1, wherein the power transmission area of the belt tooth portion is formed by an arc with a radius of curvature R_A, and the belt tooth tip portion is also formed by an arc with a radius of curvature R_B, and the radius of curvature R_A is larger than R_B. belt. 3. The toothed belt according to claim 2, wherein the center points of the circular arcs forming the power transmission region of the belt tooth portion and the belt tooth tip portion are both within the belt body. 4. The starting point is a point where the power transmission area of the belt teeth is 10 to 25% of the height of the belt teeth from the belt land line,
Further, it is a region whose end point is a point 50 to 80% of the belt tooth height from the line, and the angle between the straight line connecting the starting point S and the ending point F and the belt tooth center line is 9 to 20 degrees. The toothed belt according to claim 1. 5. The corner located at the boundary between the power transmission area and the belt tooth tip is located at a height of 5 points from the belt land line to the belt tooth tip.
The toothed belt according to claim 1, 2, 3 or 4, which coincides with the end points F that are 0 to 80% apart. 6. A tensile member is embedded on the pitch line of the belt body, the belt body has teeth at a constant pitch, and the belt teeth consist of a belt tooth tip, a power transmission region, and a belt tooth tip,
The toothed belt comprises a toothed belt having at least two or more protrusions on the belt tooth tip and a corner portion at the boundary between the power transmission region and the belt tooth tip, and a pulley that meshes with the toothed belt. A toothed belt drive device in which a protrusion and a corner provided on the tip of a belt tooth are brought into contact with a pulley groove wall surface when the belt and pulley mesh. 7. With at least one side surface of the belt tooth portion in contact with the pulley groove wall surface, backlash is provided between the belt tooth root portion and the pulley groove wall, and between the belt tooth tip portion and the pulley groove wall, and the belt 7. The toothed belt drive device according to claim 6, wherein the power transmission region of the tooth portion is brought into contact with the pulley groove wall within that region.