JP4683620B2 - Belt drive - Google Patents

Description

  The present invention relates to a belt transmission device that transmits power by means of a friction transmission belt, and particularly relates to the technical field of the structure of a transmission that can change the number of revolutions transmitted from a driving side to a driven side.

  Conventionally, as a belt transmission device of this type, for example, as disclosed in Patent Document 1, a driving pulley is provided on the crankshaft side of an automobile engine, while a normal rotation is provided on a driven shaft side of an auxiliary machine. A flat pulley and a flat pulley for low-speed rotation are provided on the same axis, and the flat belt spanned between the driving and driven flat pulleys is displaced in the belt width direction, and the driven side rotated by the flat belt is moved. 2. Description of the Related Art There is known an automobile accessory drive device in which a flat pulley is switched between the normal rotation and the low-speed rotation.

  In the above, a reduction gear is provided between the driven low-speed rotating flat pulley and the auxiliary drive shaft, and the driven flat pulley is switched between normal rotation and low-speed rotation. Therefore, since the rotation speed of the auxiliary machine can be switched between a predetermined speed ratio and a lower speed ratio with respect to the engine rotation speed, a component such as an electromagnetic clutch that increases the weight, cost, and power consumption can be obtained. Without using it, it is possible to reduce the drive loss of the auxiliary machine in the high rotation range and reduce the fuel consumption of the engine.

  However, in general, in a transmission device using a flat belt, there is a difficulty in that the belt meanders during traveling or travels to a side closer to one side of the pulley. This is because the flat belt is more sensitive to changes in equipment components than other belts, such as deviation of the pulley shaft from its normal position, pulley shaft deflection due to changes in shaft load, and pulley vibration. When such meandering / offset running occurs, the flat belt comes into contact with the flange of the pulley, causing fuzz on the side surfaces and fraying of the core wire.

  Conventionally, it has been known that a crown is attached to the outer peripheral surface of a flat pulley (forms a medium-high curved surface) to solve such a reliability problem, and the crown is formed in a spherical shape centered on the rotation center of the pulley. The proposal of forming is also made (refer patent document 2).

There is also a proposal to prevent meandering and shifting by forming a large number of grooves on the outer peripheral surface of the flat pulley at intervals in the circumferential direction (see Patent Document 3). The groove extends symmetrically from the center of the width of the pulley so as to form a "<" shape on both sides, and generates a frictional force that brings the flat belt to the center between the flat belt and the pulley. .
JP 2005-23909 A Japanese Utility Model Publication No.59-45351 JP-A-6-307521

  However, none of the above proposals can solve the problems involved in the flat belt transmission. That is, when the crown is formed on the pulley as in the first proposed example, the width of the belt can be reduced by reducing the curvature radius of the crown with an emphasis on running stability of the flat belt (preventing meandering and deviation). Stress concentrates in the center, and the entire belt width cannot be used effectively for transmission, leading to early fatigue of the core and a reduction in transmission capability.

  Further, if the flat pulley is grooved as in the above-mentioned second proposal, it is inevitable that the production cost of the flat pulley will be high. Misalignment cannot be reliably prevented.

  In addition to the problems associated with such flat belt transmission, in the above-described conventional accessory driving device (the one disclosed in Patent Document 1), a reduction gear is provided between the driven low-speed rotating pulley and the accessory driving shaft. Since oil for lubricating the gear is also required, there is a problem that the weight and cost increase, and there is still a problem of driving loss due to the meshing of the gear.

  The present invention has been made in view of such various points, and an object of the present invention is to reliably prevent meandering and deviation of the flat belt in a variable speed transmission device using the flat belt. In addition, the speed reduction gear and the like are eliminated to eliminate the need for oil for lubrication, thereby further reducing weight, cost, and driving loss.

  In order to achieve the above object, in the present invention, as a tension pulley for applying tension to the flat belt, details will be described below, but when the flat belt is displaced on the pulley body, A self-aligning pulley is employed that can displace the pulley body by utilizing the shift of the axial load position applied to the pulley body due to the tension of the belt, thereby correcting the running position of the belt closer to the center.

  In addition, according to the present invention, at least one pulley on the driving side and the driven side has a plurality of friction surfaces having different diameters, and the automatic adjustment for preventing the flat belt from meandering and shifting as described above. By using the function of the center pulley, the self-aligning pulley is moved in the pulley axial direction, the flat belt is moved in the width direction following this, and wound around one of the friction surfaces having different diameters. I tried to hang it.

Specifically, the invention of claim 1 is a belt transmission device in which a friction transmission belt is wound around a plurality of pulleys,
The friction transmission belt is a flat belt, and at least one pulley on the driving side and the driven side around which the flat belt is wound is formed with a plurality of friction surfaces having different diameters,
Further, a tension pulley comprising a pulley body around which the flat belt is wound and a support mechanism for supporting the pulley body so as to be rotatable about a pulley axis and swingable about a predetermined pivot axis is provided. And
The pivot shaft of the tension pulley is tilted at a predetermined tilt angle on the front side in the rotational direction of the pulley body with respect to the axial load direction when viewed along the pulley shaft direction.
The tension pulley support mechanism is configured to be capable of reciprocating in a range corresponding to a plurality of friction surfaces of the driving side to the driven side pulley in the pulley axis direction along with the pivot shaft of the pulley body. To do.

  With the above configuration, first, when the flat belt is wound around the driving side and driven side pulleys and the pulley body of the tension pulley is stopped in the pulley axial direction, the flat belt is offset on the pulley body, When the axial load is shifted from the pivot position in the width direction of the pulley body, the rotational load acts on the pulley body around the pivot axis due to the axial load, and the pulley body rotates and swings around the pivot axis. )

  Here, as will be described in detail later, the pivot is tilted at a predetermined tilt angle to the front side in the rotational direction of the pulley body with respect to the axial load direction when viewed along the pulley axis direction, and the tilt angle is 90. The pulley body tilts so that the side opposite to the side from which the flat belt is offset becomes higher, while when the tilt angle is more than 0 degree and less than 90 degrees, the pulley body is In addition to inclining, the side where the flat belt is offset becomes the front side in the belt running direction.

  When the pulley body is inclined or skewed in this way, a force acts so as to return the offset from the pulley body to the flat belt, and the piece acting on the belt by the return force and the characteristics of the transmission device. The flat belt starts to run at a position where the shifting force is balanced. As described above, the tension pulley has an automatic alignment function that automatically adjusts the traveling position of the flat belt toward the center (hereinafter, also referred to as an automatic alignment pulley). As in the conventional proposal examples (Patent Documents 2 and 3), meandering and shifting of the flat belt can be surely prevented without causing early fatigue of the core wire, lowering of transmission capability and increase of manufacturing cost.

  Such a self-aligning pulley allows the flat belt to run at a substantially constant position in the width direction when the pulley body is stopped in the pulley axial direction (belt width direction) as described above. If the main body and the pivot are moved in the pulley axis direction, the flat belt will be relatively displaced in the width direction on the pulley body, so that the axial load is shifted from the pivot position to one side in the pulley body width direction. To come. Due to this axial load, as described above, the pulley body is rotationally displaced about the pivot, and a force is applied to return the offset from the pulley body to the flat belt.

  For this reason, when the pulley body of the self-aligning pulley is moved in the pulley axial direction together with the pivot by the support mechanism, a return force continues to be applied to the flat belt on the pulley body, thereby The belt follows the movement of the pulley body and moves in the pulley axis direction. In this way, the rotational speed ratio of the driven pulley to the driving pulley is changed by changing the running position of the flat belt in the belt width direction and winding it on the friction surface of either the driving pulley or the driven pulley. can do.

  Therefore, according to the belt transmission device described above, the self-aligning pulley is provided as a tension pulley between the driving side pulley and the driven side pulley. Belt meandering and offset running can be reliably prevented, and this is advantageous in fully exerting its transmission capability. Further, by moving the pulley main body of the self-aligning pulley in the pulley axial direction and moving the flat belt in the width direction following this, the friction surface of the driving side to the driven side pulley around which the flat belt is wound. Can be changed to change the gear ratio.

  By providing a plurality of friction surfaces with different diameters on the driving side or driven side pulley and changing the friction surface around which the flat belt is wound, the number of revolutions transmitted from the driving side to the driven side can be made variable. Therefore, a reduction gear and oil for lubrication are not necessary, and the weight and cost can be reduced, and the driving loss due to the meshing of the gear can be eliminated.

  Here, the operation of the self-aligning pulley will be described in detail. When the tilt angle of the pivot that is the swing center of the pulley body is 90 degrees, that is, when the pivot is orthogonal to the direction of the axial load, the pulley body Is rotationally displaced (oscillated) so that the side of the flat belt that has been offset moves in the direction of the axial load. That is, when the height of the axial load is viewed, the flat belt is inclined so that the side where the flat belt is offset is low and the opposite side is high, that is, the outer peripheral surface of the pulley body is inclined in the same manner as the crown. As a result, a return force in the direction opposite to the above-described offset direction is applied to the flat belt.

  On the other hand, when the tilt angle is less than 90 degrees, the rotational displacement of the pulley main body when the flat belt is offset includes not only the component in the axial load direction but also the longitudinal direction orthogonal to the axial load direction. (The direction in which the flat belt is running in contact with the pulley body) is added. In other words, the pulley body not only inclines in the axial load direction, but the side on which the belt is offset moves to the front side in the belt traveling direction and is in contact with the belt in an oblique manner. Also, the belt is given a force in the direction of returning the offset from the pulley body.

  After all, when the pulley body is supported by the shaft member so as to be swingable around the pivot shaft, the tilt angle of the pivot shaft exceeds 0 degree and less than 90 degrees. When the belt is offset in the direction, the return force due to the pulley body tilting so as to produce a height difference in the axial load direction and the return force due to the pulley body being oblique to the belt. Both belts work, and the belt travels at a position where the resultant force of both return forces and the offset force acting on the belt are balanced by the characteristics of the belt transmission.

  In the return force due to the inclination and the return force due to the oblique, the latter is more effective in preventing the deviation. Therefore, in order to effectively use the return force due to the oblique, the inclination angle is preferably set. It is over 0 degree and 45 degrees or less. On the other hand, when the tilt angle is close to 0 degrees, it is difficult to generate a rotational moment centering on the above-mentioned pivot axis. More preferably, the tilt angle is 5 degrees or more and 45 degrees or less, or 10 degrees or more and 30 degrees. It is as follows.

  By making the tilt angle more than 0 degrees and less than 90 degrees, it is possible to effectively prevent the flat belt from meandering and running away from it, which means that the flat belt can also be moved effectively. It is.

  More specifically, for example, a cylindrical shaft member that is provided integrally with the pulley main body and rotatably supports the pulley main body around the pulley shaft; and the cylindrical shaft member. A support rod that is inserted and extends coaxially with the pulley shaft, a pin that is disposed near the center of the width of the pulley body and that constitutes the pivot, and is interposed between the shaft member and the support rod. An intermediate member that swingably supports the shaft member around the pin, and reciprocates along the support rod together with the pin; and a power source that generates power for reciprocating the intermediate member. It can be configured.

  According to this configuration, when the intermediate member is moved along the support rod by the power generated by the power source, the pin and the shaft member move in the pulley shaft direction together with the intermediate member. Along with this, the flat belt is relatively displaced in the width direction on the pulley body, the pulley body is rotationally displaced around the pin, and a force is applied to return the displacement from the pulley body to the flat belt. Then, the flat belt moves in the pulley axial direction following the movement of the pulley body.

  As the power source, various power sources such as a vacuum actuator, a motor, a linear motor, a solenoid, and a hydraulic cylinder can be adopted.

  In the belt transmission device having the above-described configuration, among the driving side and driven side pulleys, the one having a plurality of friction surfaces having different diameters may be, for example, only the driven side pulley. When the friction surface to be applied is changed, the winding length of the flat belt around the friction surface (length in the circumferential direction) changes, and the amount of slackness of the belt changes accordingly. Therefore, it is preferable that the tension pulley (self-aligning pulley) hold the pulley body together with the support mechanism so as to be movable toward and away from the flat belt, and the tension pulley presses the flat belt against the arm. And a biasing means for biasing the movement in such a manner as to automatically absorb the change in the amount of slackness of the belt by the movement of the arm (invention of claim 2).

  Alternatively, two friction surfaces having different diameters are formed on both the driving side and the driven side pulley so that the change in the amount of looseness of the belt is small, and the relatively large diameter of the driving side pulley is formed. And the relatively small diameter friction surface of the driven pulley are positioned at corresponding pulley axial positions, and the relatively small diameter friction surface of the driving pulley and the relatively large size of the driven pulley are relatively large. You may make it locate the friction surface of a diameter in the pulley axial direction position mutually corresponding (invention of Claim 3).

  In this case, it is particularly preferable that the large-diameter friction surfaces of the driving and driven pulleys have substantially the same diameter, and the small-diameter friction surfaces of both pulleys have substantially the same diameter. Item 4).

  Next, in the present invention, the flat belt is wound around a plurality of friction surfaces having different diameters from the driving side to the driven side pulley, and the above self-aligning is used as a tension pulley that applies tension to each of the flat belts. Adopt a pulley. Then, the pulley body of each of the self-aligning pulleys is moved toward and away from each flat belt, and by selectively applying tension to only one of the flat belts, the drive side to the driven side Changed pulley speed ratio.

That is, the invention of claim 5 is a belt transmission device in which a friction transmission belt is wound around a plurality of pulleys,
The friction transmission belt is composed of a plurality of flat belts, and at least one pulley on the driving side and the driven side around which the plurality of flat belts are wound, a plurality of frictions having different diameters around which the respective flat belts are wound. A surface is formed,
Furthermore, a plurality of tension pulleys comprising a pulley body around which each of the flat belts is wound, and a support mechanism that supports the pulley bodies so as to be rotatable about a pulley axis and swingable about a predetermined pivot axis. Is arranged,
The pivot shaft of each tension pulley is tilted at a predetermined tilt angle on the front side in the rotational direction of the pulley body with respect to the axial load direction when viewed along the pulley shaft direction.
The tension pulley support mechanism is configured such that the pulley body can be moved toward and away from the flat belt so that the pulley body switches between a state in which the pulley body presses the flat belt and a state in which the pulley body does not press. And

  With the above configuration, first, the self-aligning pulley described above is disposed as a tension pulley so as to apply tension to each of the plurality of flat belts wound around the driving side and driven side pulleys. As in the first aspect of the invention, meandering and shifting can be reliably prevented without causing early fatigue of the core wire of the flat belt, lowering of transmission capability, and increase of manufacturing cost.

  Further, the pulley body of each of the self-aligning pulleys is moved toward and away from the flat belt, and can be switched between a state in which the flat belt is pressed and a state in which the flat belt is not pressed. If the flat belt is pressed by only one to apply tension, the pulley rotation speed ratio from the driving side to the driven side is determined according to the diameter of the friction surface on which the flat belt is wound. It will be.

  Therefore, the belt transmission device according to claim 5 as well as the belt transmission device according to claim 1 ensures that the flat belt is meandering and deviated while applying a stable tension to the flat belt by the self-aligning pulley. In addition, the gear ratio can be changed by changing the flat belt to which tension is applied, which eliminates the need for a reduction gear, lubricating oil, etc. Driving loss due to meshing can be eliminated.

  As described above, according to the belt transmission device of the present invention, the pulley body of the tension pulley is supported so as to be rotatable around the pulley shaft and swings around the pivot shaft tilted in a predetermined direction with respect to the axial load direction. Since the flat belt is shifted in the width direction on the pulley body, the pulley body is inclined at least in the direction of the axial load so that the flat belt can be meandered and shifted and moved quickly. It can be surely solved.

  Particularly in the first to fourth aspects of the invention, since the pulley body of the tension pulley can be reciprocated in the pulley axis direction together with the pivot shaft, the flat belt follows the movement of the pulley body by a return force acting on the flat belt. The belt can be moved in the belt width direction, and the gear ratio can be changed by switching the flat belt between the plurality of friction surfaces of the driving side or driven side pulleys.

  In the fifth aspect of the invention, a flat belt is wound around each of the plurality of friction surfaces of the driving side to driven side pulleys, and the pulley body of the tension pulley for each flat belt is brought into contact with the flat belt. Since it is possible to move in the separating direction, it is possible to selectively apply tension to only one of the flat belts, thereby changing the gear ratio.

In each of the above inventions, the plurality of friction surfaces of the pulley around which the flat belt is wound have different diameters, thereby eliminating the need for a reduction gear, lubricating oil, etc., and reducing the weight and cost. It is possible to reduce the driving loss due to the meshing of the gears.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a basic configuration of a belt transmission apparatus according to Embodiment 1 of the present invention. In FIG. 1, 1 is a driving pulley and 2 is a driven pulley. A tension pulley 4 is disposed so that a tension transmission belt is applied to the flat belt 3 from the back side. Then, when the driving pulley 1 rotates counterclockwise in the figure, the flat belt 3 also runs counterclockwise in the figure and rotates the driven pulley 2.

  Note that the configuration of the belt transmission shown in the drawing is the most basic one simplified for convenience of explanation, and is merely an example, and does not limit the configuration of the present invention in any way. The belt transmission device according to the present invention can be used for automobiles, agricultural machines, various industrial machines, home appliances, and other devices, and in that case, various layouts can be adopted as necessary. Can do.

  As shown in FIGS. 2 and 3, the driving pulley 1 is a flat pulley in which a friction surface having a width approximately three times the width of the flat belt 3 is formed on the outer periphery. Is fitted into the driving shaft 1a, and is rotated integrally with the driving shaft 1a. A pivot end of an arm 16 for rotatably holding the tension pulley 4 is attached to a driving shaft 1a on the tip side of the driving pulley 1 via a bearing, and the arm 16 is attached to the tension pulley. 4 is held so as to be movable toward and away from the flat belt 3.

  Further, although not shown in the drawing, a biasing means for biasing the distal end side of the arm 16 downward in the figure is provided so that the tension pulley 4 presses the flat belt 3. As this urging means, for example, a spring member or a hydraulic or pneumatic cylinder can be used, but in the case of the layout as in this embodiment, they are urged downward by the weight of the tension pulley 4 and the arm 16. You can also make it. Furthermore, it is preferable to provide damping for the rotation of the arm 16. Hereinafter, the arm 16 is referred to as a biasing arm 16.

  On the other hand, the driven pulley 2 is fitted at the tip of the driven shaft 2a arranged in parallel to the driving shaft 1a and rotates integrally with the driven shaft 2a. The driven pulley 2 as a whole has substantially the same width as the driving pulley 1, but the outer peripheral surface thereof is divided into both ends in the axial direction of the driven shaft 2 a and has a circular cross-section with different diameters. These two friction surfaces 2b and 2c are formed.

  Of the two friction surfaces 2b and 2c, the relatively small friction surface 2b (hereinafter referred to as a small diameter friction surface) has a smaller diameter than the friction surface of the driving pulley 1 in this embodiment. The diameter of the relatively large friction surface 2c (hereinafter referred to as a large diameter friction surface) is the same as the friction surface of the driving pulley 1 in this embodiment. In addition, a tapered surface 2d whose diameter gradually increases from the small-diameter friction surface 2b toward the large-diameter friction surface 2c is formed in the middle between the two friction surfaces 2b and 2c. .

  As shown in FIG. 2, when the flat belt 3 is wound around the small-diameter friction surface 2b of the driven pulley 2, the rotation of the driving shaft 1a is increased by the flat belt 3 and transmitted to the driven shaft 2a. On the other hand, when the flat belt 3 is wound around the large-diameter friction surface 2c of the driven pulley 2 as shown in FIG. 3, the driving shaft 1a rotates as it is. A relatively low speed ratio is transmitted to the driven shaft 2a.

  Then, the friction surfaces 2b and 2c of the driven pulley 2 around which the flat belt 3 is wound have different diameters, and the flat belt 3 is simply switched between the two friction surfaces 2b and 2c. Since the transmission rotational speed from the motor to the driven side can be changed, a reduction gear and oil for lubrication thereof are unnecessary, the weight and cost can be reduced, and the drive loss due to the meshing of the gear is eliminated.

−Tension pulley structure−
In this embodiment, as a characteristic part of the present invention, as the self-aligning pulley, the tension pulley 4 is swung as the flat belt 3 is shifted toward the center, and the traveling position of the flat belt 3 is automatically adjusted toward the center. Yes. That is, as shown in detail in FIGS. 4 and 5, the tension pulley 4 includes a pulley body 5 around which the flat belt 3 is wound, and the pulley body 5 is rotatable about the pulley axis C1 and swings around the pivot axis C2. And a support mechanism 10 that supports it freely (C1 and C2 are shown only in FIG. 4).

  The support mechanism 10 includes a cylindrical shaft member 11 that supports the pulley body 5 by a bearing 12, a support rod 13, a pin 17 that forms a pivot C2, and the pulley body 5 together with the pin 17 in the pulley axis C1 direction. And a moving mechanism 6 that reciprocally moves. The moving mechanism 6 includes an intermediate member 14 and a bellows type vacuum actuator 7. The pulley body 5 is moved in the direction of the pulley axis C1 corresponding to the two friction surfaces 2b and 2c of the driven pulley 2. It is designed to reciprocate over a range.

  The support rod 13 includes an attachment part 13a attached to the urging arm 16 and a support part 13b provided following one end of the attachment part 13a. The attachment portion 13a is inserted through a through hole formed at the tip of the urging arm 16 and fastened with a nut. The support portion 13b is inserted into the intermediate member 14.

  The support portion 13b has an end opposite to the attachment portion 13a (hereinafter, an end opposite to the attachment portion 13a is called a tip of the support portion 13b, and an end on the attachment portion 13a side is a base of the support portion 13b. An insertion hole 91 that is open on the surface of the two ends 92 and two elongated holes 92 that are opposed to each other in the radial direction and extend in the axial direction are formed. A screw groove is formed in the vicinity of the opening of the insertion hole 91, and the opening is closed by screwing a stud bolt 93 described later.

  The intermediate member 14 is a tubular member having a circular cross section as a whole, which includes two halved members and has a center hole at the center of the cross section. The intermediate member 14 is inserted into the cylindrical shaft member 11 and is supported by the support rod 13 via sliding rings 21 and 21 fitted on the proximal end side and the distal end side, respectively. 13b is extrapolated. And this intermediate member 14 is supported by the said support part 13b so that a reciprocation is possible in the axial direction.

  Further, an enlarged diameter portion is formed at the tip of the intermediate member 14, and this enlarged diameter portion is fixed to the movable plate 72 of the vacuum actuator 7. Therefore, as will be described in detail later, the intermediate member 14 reciprocates in the axial direction of the support portion 13b using the vacuum actuator 7 as a drive source.

  Further, the portion of the intermediate member 14 corresponding to the diameter direction is cut into a D-shape, and by this D-cut, as shown in FIGS. Is formed. Thus, through holes extending in the radial direction from the sliding surfaces 14c toward the center hole of the intermediate member 14 are formed, and the sliding cylinder 18 is fitted in the through holes.

  Two sliding members 19 each having a D-shaped cross section are attached to the inner peripheral surface of the shaft member 11 so as to face each other in the diametrical direction. The sliding member 19 is formed on the inner surface of the shaft member 11 such that flat sliding surfaces 11a and 11a that are slidably in contact with the sliding surfaces 14c and 14c of the intermediate member 14 face each other. ing. Further, arcuate surfaces on both sides connecting both side edges of the sliding surfaces 11 a and 11 a are formed by the inner peripheral surface of the shaft member 11. Further, the shaft member 11 and the sliding member 19 are formed with support holes into which the pins 17 are fitted near the center of the width of the pulley body 5.

  The pins 17 of the support mechanism 10 are arranged to pass through the support portion 13b in the radial direction through the long holes 92 of the support rod 13, and both end portions thereof penetrate the intermediate member 14. It passes through the sliding cylinder 18 fitted into the hole and is fitted into a support hole provided in the shaft member 11 and the sliding member 19. The pin 17 is disposed at a predetermined tilt angle α on the front side in the rotational direction of the pulley body 5 with respect to the axial load direction L with respect to the rotational direction of the pulley body 5 (see FIG. 4). About the width direction of 5, it has arrange | positioned in the center vicinity (refer FIG. 5).

  Thus, the shaft member 11 and the pulley body 5 are swung around the pivot C2 formed by the pin 17 between the arc surfaces on both sides of the intermediate member 14 and the arc surfaces on both sides of the cylindrical hole of the shaft member 11. Clearances 15, 15 that allow movement are formed.

  The pin 17 moves in the axial direction in the elongated hole 92 as the intermediate member 14 reciprocates along the support portion 13b, whereby the shaft member 11 and the pulley engaged with the pin 17 are moved. The main body 5 reciprocates along the support portion 13b.

  A compression spring 94 is disposed in the insertion hole 91 of the support portion 13b, and a stud bolt 93 is screwed into the insertion hole 91 in this state. The compression spring 94 disposed between the implantation bolt 93 and the pin 17 biases the pin 17 toward the proximal end side of the support portion 13b.

  The vacuum actuator 7 is extrapolated to the support rod 13 and is stretched over the entire circumference between two side plates 71 and 72 facing each other in the axial direction and the outer peripheral edges of the side plates 71 and 72. And a bellows 73 that defines a working chamber between them.

  One of the two side plates 71, 72 is a fixed plate 71 fixed to the distal end portion of the support portion 13b, and the other is movable to the support portion 13b on the base end side of the fixed plate 71. It is the movable plate 72 supported by. An O-ring is interposed between the inner peripheral surfaces of these two side plates 71 and 72 and the outer peripheral surface of the support rod 13, thereby ensuring airtightness in the vacuum actuator 7. .

  The fixing plate 71 is provided with a connection port 75 connected to a vacuum pump (not shown) via a tube 74, and the working chamber in the vacuum actuator 7 is vacuumed by the connection port 75 and a passage in the tube 74. It communicates with the pump chamber of the pump. On the other hand, the diameter-enlarged portion of the intermediate member 14 is fixed to the movable plate 72.

  As shown in FIG. 2, when the working chamber in the vacuum actuator 7 is in a normal pressure state and the working chamber is brought to a negative pressure by the operation of the vacuum pump, the movable plate 72 is attached to the compression spring 94. The intermediate member 14 moves to the front end side of the support rod 13 against the force, and accordingly, the pin 17, the shaft member 11, and the pulley body 5 are integrated into the support rod 13. (See FIG. 3).

  On the other hand, when the working chamber in the vacuum actuator 7 is in a negative pressure state as shown in FIG. 3 and the working chamber is opened to the atmospheric pressure, for example, to the atmospheric pressure, the pin 17 is urged by the urging force of the compression spring 94. The shaft member 11 and the pulley main body 5 are integrally moved to the proximal end side of the support rod 13, and accordingly, the intermediate member 14 and the movable plate 72 are moved to the proximal end side (right side in the drawing) of the support rod 13. Move (see FIG. 2).

  Thus, the pulley body 5 and the pin 17 are reciprocated in the direction of the pulley axis C1, and the high-speed specific position (FIG. 2) corresponding to the position of the small-diameter friction surface 2b of the driven pulley 2 and the driven side The position is changed to one of two positions, a low speed ratio position (FIG. 3) corresponding to the position of the large-diameter friction surface 2c of the pulley 2.

−Preventing meandering and sideways travel−
1, 2 or 3, that is, in the state where the pulley body 5 of the tension pulley 4 is positioned at either the high speed ratio position or the low speed ratio position, as shown in FIG. When the flat belt 3 hung near the center of the width of the belt approaches the one side of the pulley body 5 from the center of the pulley body 5 as indicated by the chain line, the shaft load is shifted from the position of the pin 17 to one side of the pulley body 5 and acts on the shaft member 11. To come. As a result, a rotational moment about the pin 17 acts on the shaft member 11, and the shaft member 11 rotates and swings around the pin 17 together with the pulley body 5.

  That is, as schematically shown only in the intermediate member 14, the pin 17 and the shaft member 11 in FIG. 6, even when the flat belt 3 is offset as described above and the position of the axial load L is shifted, the direction of the axial load is temporarily assumed. Is parallel to the pin 17 (when L0), no rotational moment is generated around the pin 17, but the direction of the axial load L is inclined with respect to the direction of the pin 17 by an angle α as in this embodiment. Then, the rotational force around the pin 17 is generated by the component force L1, and the shaft member 11 is rotationally displaced. The angle α corresponds to the tilt angle α of the pin 17 with respect to the direction of the axial load L.

  In this embodiment, the swinging pivot C2 (pin 17) of the pulley body 5 is rotated in the rotational direction of the pulley body 5 with respect to the axial load L (see FIG. 4). Since the belt traveling direction A) is tilted forward, the pulley body 5 is rotationally displaced around the tilted pin 17 as shown in FIG. 8 (indicated by arrow VIII in FIG. 4). As shown in FIG. 7 (plan view), the side on which the flat belt 3 is offset is in front of the belt running direction A as shown in FIG. 7 (plan view). Thus, the flat belt 3 is obliquely crossed. 4, 7, and 8, the state where the pulley body 5 is rotationally displaced is indicated by a chain line.

  Thus, the flat belt 3 is subjected to a return force (a force for returning the offset) caused by the pulley body 5 being in an oblique state and a return force caused by the inclination of the pulley body 5. The deviation of the belt 3 is prevented. That is, in a state where the pulley body 5 is stopped in the pulley axis C1 direction, the flat belt 3 depends on the return force due to the pulley body 5 being inclined and inclined and the characteristics of the belt transmission device. Therefore, even if the flat belt 3 is largely displaced, the flat belt 3 is returned to a position where the return force and the offset force are balanced.

  In this embodiment, the sliding surfaces 14c and 11a of the intermediate member 14 and the shaft member 11 are brought into contact with each other by the axial load, and an appropriate sliding resistance acts between the both sliding surfaces 14c and 11a. When the pulley body 5 is traveling near the center of the pulley body 5, the pulley body 5 can be prevented from slightly swinging due to the traveling vibration of the flat belt 3, etc. It is prevented that the main body 5 reacts sensitively and is rotationally displaced, thereby causing the hunting that the pulley main body 5 swings from side to side.

  As described above, by using the tension pulley 4 as a self-aligning pulley, a stable tension can be applied to the flat belt 3, and the meandering and shifting can be reliably prevented. It will be advantageous to fully demonstrate the transmission capability.

-Speed change operation-
Next, for example, as shown in FIG. 2, the vacuum actuator is moved from a state in which the pulley body 5 is in the high speed ratio position and the flat belt 3 is wound around the small diameter friction surface 2b of the driven pulley 2 (high gear ratio state). When the pulley body 5 is moved to the distal end side (the left side in FIG. 2) of the support rod 13 by the operation of 7, the flat belt 3 is relatively displaced toward the proximal end side of the support rod 13 on the pulley body 5. The axial load L is shifted from the position of the pivot C2 to one side in the pulley body 5 width direction and acts on the shaft member 11. As described above, the pulley body 5 is rotationally displaced about the pivot C2 by the axial load L, and the force that returns the offset from the pulley body 5 to the flat belt 3, that is, the front end side of the support rod 13 (FIG. 2). To the left).

  Therefore, when the pulley body 5 is moved to the tip side of the support rod 13, the force toward the tip side of the support rod 13 continues to act on the flat belt 3, and the flat belt 3 moves the pulley body 5. It follows and moves to the front end side of the support rod 13. As a result, the flat belt 3 moves on the friction surface on the outer periphery of the driving pulley 1 toward the base end side of the driving shaft 1a, and in the driven pulley 2, the small-diameter friction surface 2b is changed to a tapered surface 2d continuous thereto. When the pulley body 5 moves and the pulley body 5 reaches the low speed ratio position as shown in FIG. 3, it is wound around the large-diameter friction surface 2c. And it will be in the low speed ratio state in which rotation of the driving | operation side pulley 1 is transmitted to the driven pulley 2 with the same rotation speed.

  On the contrary, as shown in FIG. 3, the pulley main body 5 is in the low speed ratio position and the pulley main body 5 is moved as described above from the low speed ratio where the flat belt 3 is wound around the large-diameter friction surface 2c. When the support rod 13 is moved to the base end side (right side in the figure), the flat belt 3 is also moved following the movement of the pulley body 5, and the pulley body 5 is moved to the high speed ratio position as shown in FIG. If it reaches, the flat belt 3 is wound around the small-diameter friction surface 2 b of the driven pulley 2. In this way, the rotation of the driving pulley 1 is increased and the high speed ratio state is transmitted to the driven pulley 2.

  When the friction surface of the driven pulley 2 around which the flat belt 3 is wound changes as described above, the winding length (circumferential length) of the flat belt 3 with respect to the two friction surfaces 2b and 2c changes. Therefore, the amount of looseness of the flat belt 3 changes accordingly. On the other hand, in this embodiment, the pulley body 5 of the tension pulley 4 that presses the slack side span (upper belt span in FIG. 1) of the flat belt 3 is moved together with the support mechanism 10 by the urging arm 16 to the flat belt 3. Since the biasing arm 16 is rotated, the change in the slack amount of the flat belt 3 is automatically absorbed.

  Therefore, according to the belt transmission device according to the first embodiment described above, the tension pulley 4 that applies tension to the flat belt 3 is the self-aligning pulley, so that the pulley body 5 is stopped in the pulley axis C1 direction. Then, while applying a stable tension to the flat belt 3, it is possible to surely prevent the flat belt 3 from meandering and shifting, which is advantageous in sufficiently exerting its transmission capability. In addition, unlike conventional proposals for preventing meandering of belts (for example, those of Patent Documents 2 and 3), early fatigue of the core wire, reduction in transmission capability, and increase in manufacturing cost are not caused.

  On the other hand, if the pulley body 5 of the tension pulley 4 is moved in the direction of the pulley axis C1, the flat belt 3 is moved in the width direction following this, and the size of the driven pulley 2 and the two friction surfaces 2b, 2c, thereby switching between a low speed ratio state in which the pulley rotation on the driving side is directly transmitted to the driven side and a high speed ratio state in which the pulley rotation is accelerated and transmitted, that is, The number of revolutions transmitted from the driving side to the driven side can be changed.

  Since the driven pulley 2 is provided with two friction surfaces 2b and 2c having different diameters and the flat belt 3 is switched, the gear ratio from the driving side to the driven side can be made variable. This eliminates the need for gears and oil for lubrication thereof, thereby reducing the weight and cost and eliminating the drive loss due to the meshing of the gears.

  In addition, the self-aligning function of the tension pulley 4 as described above can prevent the flat belt 3 from meandering and shifting, and the running position of the flat belt 3 can be changed in the belt width direction so that different friction surfaces 2b, Since it is possible to change to 2c, it is not necessary to provide flanges on the driving side and driven side pulleys 1 and 2 as well as the pulley body 5 of the tension pulley 4, so there is no risk of belt life reduction due to flange contact. .

  However, the pulleys 1 and 2 on the driving side and the driven side may be provided with flanges with an interval so that the traveling flat belt 3 does not normally contact. This is effective for preventing the flat belt 3 from falling off when the pulley body 5 is moved in the pulley axial direction in a state where the rotation of the tension pulley 4 is stopped.

  Moreover, in the above-mentioned embodiment, although the crown is not attached to the outer peripheral surface of the pulley main body 5 of the tension pulley 4, you may make it attach a loose crown here. This is because a large load on the flat belt 3 can be avoided if the crown is gentle.

  Further, in the above-described embodiment, the tension pulley 4 is disposed only on the slack side span of the flat belt 3, but not limited to this, for example, as shown in FIG. A tension pulley 8 is provided, and the tension pulley 8 can be connected by a spring member 9 or the like so as to move in conjunction with the tension pulley 4.

  By so doing, when the winding length of the flat belt 3 around the driven pulley 2 changes as described above at the time of shifting, the tension change of the tension side span can be mitigated by the movement of the tension pulley 8. As compared with the case where the slack of the flat belt 3 is absorbed only on the slack side as in the first embodiment, the tension fluctuation can be more effectively mitigated.

(Embodiment 2)
FIGS. 10-12 shows the basic composition of the belt transmission apparatus which concerns on Embodiment 2 of this invention. In the second embodiment, two friction surfaces 2b and 2c having different diameters are not provided only on the driven pulley 2 as in the first embodiment, but two different diameters are similarly provided on the driving pulley 1. Friction surfaces 1b and 1c and a tapered surface 1d are provided. Except for this point, the configuration of the belt transmission device of the second embodiment is the same as that of the first embodiment, so the same members are denoted by the same reference numerals and the description thereof is omitted.

  In the second embodiment, the diameter of the large-diameter friction surface 1b of the driving pulley 1 is substantially the same as the large-diameter friction surface 2b of the driven pulley 2, and the small-diameter friction surface 1c of the driving pulley 1 is The diameter is substantially the same as the small diameter friction surface 2 c of the driven pulley 2. As shown in FIGS. 11 and 12, the large-diameter friction surface 1b of the driving pulley 1 and the small-diameter friction surface 2b of the driven pulley 2 are at substantially the same position in the pulley axial direction, and the driving pulley The small-diameter friction surface 1c of 1 and the large-diameter friction surface 2c of the driven pulley 2 are at substantially the same position in the pulley axial direction.

  Therefore, according to the belt transmission device of the second embodiment, in the state where the pulley body 5 is stopped in the direction of the pulley axis C1 by the tension pulley 4 which is a self-aligning pulley, as in the first embodiment, the flat belt The belt 3 can be stably prevented from meandering and offset running without causing early fatigue of the core wire, lowering of transmission capability, and increase of manufacturing cost. In addition, there is no need to provide flanges on the tension pulley 4 and the driving and driven pulleys 1 and 2, and there is no possibility of belt life reduction due to flange contact.

  Further, by moving the pulley body 5 of the tension pulley 4 in the pulley axis C1 direction, the flat belt 3 is moved in the width direction, and between the two friction surfaces 1b and 1c of the driving pulley 1 and the driven pulley. 2 can be switched between the two friction surfaces 2b and 2c. That is, as shown in FIG. 11, the flat belt 3 is wound around the large-diameter friction surface 1b of the driving-side pulley 1 and the small-diameter friction surface 2b of the driven-side pulley 2 with the pulley body 5 of the tension pulley 4 at the high speed ratio position. If it is made to run, the pulley rotation is increased and a high speed ratio state is transmitted to the driven side.

  On the other hand, as shown in FIG. 12, when the pulley body 5 of the tension pulley 4 is set to the low speed ratio position, the flat belt 3 is wound around the small-diameter friction surface 1c of the driving pulley 1 and the large-diameter friction surface 2c of the driven pulley 2. At this time, the rotation of the driving pulley 1 is decelerated and transmitted to the driven pulley 2 at a low speed ratio.

  Since the gear ratio can be changed in this manner, a reduction gear, lubricating oil, etc. are no longer required as in the first embodiment, and the weight and cost can be reduced, and driving loss due to gear meshing can be eliminated. it can.

  In addition, in the belt transmission device of the second embodiment, the large-diameter friction surfaces 1b and 2a of the driving and driven pulleys 1 and 2 are substantially the same diameter, and the small-diameter friction surfaces of both pulleys 1 and 2 are the same. Since both 1c and 2c have substantially the same diameter, the amount of slackness of the flat belt 3 hardly changes between the high speed ratio state and the low speed ratio state. There is an advantage that it is much smaller than

  Therefore, the belt transmission device according to the second embodiment is suitable for the case where the diameters of the driving and driven pulleys 1 and 2 are relatively large, and the change in the belt slack amount is relatively large with respect to the change in the gear ratio. Yes. If the large and small diameter friction surfaces 1b and 1c of the driving pulley 1 and the small and large diameter friction surfaces 2b and 2c of the driven pulley 2 are made to correspond to each other as described above, the first embodiment will be described. In comparison, since the change in the amount of looseness of the flat belt 3 becomes smaller, the diameters of the friction surfaces do not necessarily have to be the same as described above.

  In the belt transmission devices of the first and second embodiments described above, the vacuum actuator 7 is used as a drive source for moving the pulley body 5 of the tension pulley 4. However, the drive source is not limited to this. It is possible to use various devices such as a motor, a linear motor, a solenoid, and a hydraulic cylinder. If the drive source is constituted by a stepping motor or the like, the flat belt 3 can be driven at two or more traveling positions, and in this way, three or more stages of speed change are possible.

(Embodiment 3)
13 and 14 show a basic configuration of a belt transmission device according to Embodiment 3 of the present invention. In the third embodiment, as in the first and second embodiments, the single flat belt 3 is moved in the width direction so as to be switched between the plurality of friction surfaces of the driving side or driven side pulleys 1 and 2. .., And flat belts 3, 3,... Are wound around a plurality of friction surfaces (three in the illustrated example) in advance, and one of the flat belts 3 is selectively tensioned. To determine the pulley rotational speed ratio transmitted from the driving side to the driven side.

  Except for this point, the basic configuration of the belt transmission device of the third embodiment is substantially the same as that of the first and second embodiments. Therefore, the corresponding members are denoted by the same reference numerals for the sake of convenience, and the description thereof is omitted.

  In the illustrated belt transmission device, as an example, three friction surfaces having different diameters are formed on each of the pulleys 1 and 2 on the driving side and the driven side. That is, in addition to the large-diameter friction surface 1b and the small-diameter friction surface 1c, the driving-side pulley 1 is formed with an intermediate-diameter friction surface 1e having an intermediate diameter therebetween, and the driven pulley 2 also has a small-diameter and large-diameter surface. In addition to the diameter friction surfaces 2b and 2c, an intermediate friction surface 2e between them is formed. The large, medium, and small friction surfaces of the driving and driven pulleys 1 and 2 have substantially the same diameter.

  As shown in FIG. 14, the large-diameter friction surface 1b, small-diameter friction surface 1c and relay friction surface 1e of the driving pulley 1 are the small-diameter friction surface 2b, large-diameter friction surface 2c and medium-diameter of the driven pulley 2, respectively. It is in the substantially same position about the friction surface 2e and a pulley axial direction, and the flat belts 3, 3, ... are wound around each. A plurality of (three in the illustrated example) tension pulleys 4, 4,..., Which are self-aligning pulleys as in the first and second embodiments, so as to apply tension to the slack side span of each flat belt 3. Is arranged.

  The structure of the tension pulley 4 is basically the same as that of the first and second embodiments, and when the offset of the flat belt 3 occurs on the pulley body 5, the shift of the axial load position is utilized. The pulley main body 5 is displaced so as to be inclined or oblique. However, in the third embodiment, it is not necessary to reciprocate the pulley main body 5 in the direction of the pulley axis C1. The moving mechanism 6 is omitted from FIG.

  That is, as shown in FIG. 15, an example of the tension pulley 4 is a support mechanism that supports the pulley body 5 so as to be rotatable about the pulley axis and swingable about the pivot axis. A cylindrical shaft member 11 supported by the shaft member 11, a support rod 13 having a distal end side 13 a inserted in the shaft member 11, and a pin 17 constituting a pivot.

  Although not shown, the other end 13b of the support rod 13 is attached to a fixed portion of the belt transmission device via a movable member, and the pulley body 5 and the shaft are operated by the operation of the movable member. The member 11, the support rod 13, the pin 17 and the like are movable in the contact / separation direction (vertical direction in FIG. 13) with respect to the flat belt 3.

  Then, by moving the pulley body 5 and the like in the contact / separation direction with respect to the flat belt 3, the tension pulleys 4, 4,... Apply tension by pressing the flat belt 3 with the pulley body 5. And a state where it is not pressed, and tension can be selectively applied only to any one of the flat belts 3. For the movement of the movable member, a vacuum actuator as in Embodiments 1 and 2 can be used as a drive source. In addition, various devices such as a motor, a linear motor, a solenoid, and a hydraulic cylinder can be used. Can be used.

  Therefore, according to the belt transmission device of the third embodiment, tension is selectively applied to any one of the plurality of flat belts 3, 3,... Wound around the driving side and driven side pulleys 1, 2. As a result, pulley rotation can be transmitted at a ratio of the friction surface diameters of the driving and driven pulleys 1 and 2 around which the selected flat belt 3 is wound. The ratio can be changed.

  Therefore, as in the first and second embodiments, a reduction gear, lubricating oil, and the like are not necessary, and the weight and cost of the belt transmission can be reduced, and driving loss due to gear meshing can be eliminated. .

  Since the tension pulley 4 that applies tension to the flat belt 3 selected as described above is a self-aligning pulley, a stable tension is applied to the flat belt 3 as in the first and second embodiments. While being applied, meandering and deviation can be reliably prevented without causing early fatigue of the core wire, lowering of transmission capability, and increase of manufacturing cost.

  As described above, the belt transmission device according to the present invention has the self-aligning function provided to the tension pulley, so that the meandering and the offset running can be reliably performed without reducing the reliability of the flat belt. Since a plurality of friction surfaces with different diameters are provided on the driving side or driven side pulley, there is no need for a speed reduction gear, lubricating oil, etc. Since a highly efficient transmission can be provided, it can be used for, for example, automobiles, agricultural machines, various industrial machines, home appliances, and other devices.

FIG. 2 is a front view of the belt transmission device according to the first embodiment. It is a side view of the apparatus when a flat belt is made to drive in a high speed ratio state. It is a side view of the apparatus when a flat belt is made to drive in a low speed ratio state. It is a longitudinal cross-sectional view (IV-IV sectional view of FIG. 5) of a tension pulley. It is VV sectional drawing of FIG. It is a figure explaining that a rotational moment generate | occur | produces in the shaft member 11 by the shaft load in the use condition of a tension pulley. It is a top view which shows the use condition of a tension pulley. FIG. 5 is a view taken along arrow VIII in FIG. 4. FIG. 3 is a view corresponding to FIG. 1 according to a modification in which a tension pulley is also disposed on a tension side belt span. FIG. 3 is a view corresponding to FIG. 1 relating to a belt transmission device of a second embodiment. FIG. 3 is a view corresponding to FIG. It is the figure equivalent to FIG. FIG. 6 is a view corresponding to FIG. 1 according to a belt transmission device of a third embodiment. It is a side view of the same apparatus. It is a perspective view which shows schematic structure of the tension pulley in the apparatus.

Explanation of symbols

1 Driving pulley 1b Large-diameter friction surface 1c Small-diameter friction surface 1e Medium-diameter friction surface 2 Driven pulley 2b Small-diameter friction surface 2c Large-diameter friction surface 2e Medium-diameter friction surface 3 Flat belt 4 Tension pulley (self-aligning pulley)
5 Pulley body 6 Movement mechanism 7 Vacuum actuator 10 Support mechanism 11 Shaft member 13 Support rod 14 Intermediate member 16 Arm 17 Pin C1 Pulley shaft C2 Axis α Inclination angle

Claims (5)

A belt transmission device in which a friction transmission belt is wound around a plurality of pulleys,
The friction transmission belt is a flat belt, and at least one pulley on the driving side and the driven side around which the flat belt is wound is formed with a plurality of friction surfaces having different diameters,
Further, a tension pulley comprising a pulley body around which the flat belt is wound and a support mechanism for supporting the pulley body so as to be rotatable about a pulley axis and swingable about a predetermined pivot axis is provided. And
The pivot shaft of the tension pulley is tilted at a predetermined tilt angle on the front side in the rotational direction of the pulley body with respect to the axial load direction when viewed along the pulley shaft direction.
The tension pulley support mechanism is configured to be capable of reciprocating in a range corresponding to a plurality of friction surfaces of the driving side to the driven side pulley in the pulley axis direction along with the pivot shaft of the pulley body. Belt transmission device. The belt transmission device according to claim 1,
The driven pulley has a plurality of friction surfaces;
An arm for holding the pulley body of the tension pulley together with its support mechanism so as to be movable toward and away from the flat belt;
A biasing means for biasing the arm so that the pulley body presses the flat belt;
A belt transmission device is provided. The belt transmission device according to claim 1,
The driving side and driven side pulleys each have two friction surfaces with different diameters,
The relatively large-diameter friction surface of the driving pulley and the relatively small-diameter friction surface of the driven pulley are in the corresponding axial position of the pulley, and the relatively small-diameter friction of the driving pulley is A belt transmission device characterized in that the surface and the relatively large-diameter friction surface of the driven pulley are at mutually corresponding pulley axial positions. The belt transmission device according to claim 3,
A belt transmission device characterized in that the large friction surfaces of the driving and driven pulleys have substantially the same diameter, and the small friction surfaces of both pulleys also have substantially the same diameter. A belt transmission device in which a friction transmission belt is wound around a plurality of pulleys,
The friction transmission belt is composed of a plurality of flat belts, and at least one pulley on the driving side and the driven side around which the plurality of flat belts are wound, a plurality of frictions having different diameters around which the respective flat belts are wound. A surface is formed,
Furthermore, a plurality of tension pulleys comprising a pulley body around which each of the flat belts is wound, and a support mechanism that supports the pulley bodies so as to be rotatable about a pulley axis and swingable about a predetermined pivot axis. Is arranged,
The pivot shaft of each tension pulley is tilted at a predetermined tilt angle on the front side in the rotational direction of the pulley body with respect to the axial load direction when viewed along the pulley shaft direction.
The tension pulley support mechanism is configured such that the pulley body can be moved toward and away from the flat belt so that the pulley body switches between a state in which the pulley body presses the flat belt and a state in which the pulley body does not press. Belt transmission device.

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