JPH0724697Y2 - Belt drive clutch / brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a belt driving device provided in a mower equipped with a cutter or the like, including a driving pulley, a driven pulley, and
A drive belt hung around both pulleys, a swing arm having a swing fulcrum at a position different from the rotation center of the drive pulley, and a rod slidably supported by the swing arm and supporting a bearing of a driven pulley. , Consisting of a spring that urges the rod in the direction that expands the distance between the axes of both pulleys, and a belt pulley cover. The swing arm swing operation changes the distance between the axes of the pulleys to turn the clutch on and off. The present invention relates to a clutch / brake device for a belt drive device.

(Prior Art) In a conventional belt drive device of this type, as shown in FIG.
It is only formed in a shape that covers the portion and prevents the drive belt 16 from falling off when the clutch is off. Reference numeral 7 is a cutter, and 17 is a driven pulley bearing. Therefore, when the clutch is off, the drive belt is released on the drive pulley side, and at the same time, on the driven pulley side, the drive belt 16 is also released radially outward from the driven pulley 12 as shown by the solid line in FIG. .

When the driven pulley 12 fixed to the same driven shaft 15 as the cutter 7 etc. is also in the free state in this way, after the clutch off operation, it waits until the rotation due to the inertial force of the cutter 7 etc. naturally stops. It must be done and it takes time for the cutter 7 to stop.

On the other hand, if the vehicle is to be stopped quickly when the clutch is off, a special member for braking must be arranged and linked with the clutch operation, which is costly. As a prior art, there is Shoukaisho 63-28322.

(Object of the Invention) The object of the present invention is to improve the shape of the conventional pulley belt cover and use it as a brake device that automatically operates when the clutch is off, thereby eliminating the need to add a new brake component. , To be able to provide an inexpensive brake mechanism.

(Technical Means for Achieving the Purpose) In order to achieve the above object, the present invention provides a drive pulley, a driven pulley, a drive belt hung on both pulleys, and a position different from the rotation center of the drive pulley. A swing arm having a swinging fulcrum, a rod slidably supported by the swing arm and supporting a bearing of a driven pulley, and a spring for urging the rod in a direction to increase the axial distance between the pulleys. , A belt pulley cover, in which a swing arm swinging operation changes the distance between the axes of the pulleys to turn the clutch on and off, a belt outlet, an inlet or an outlet of the driven pulley cover. An inclined portion that slides and presses the drive belt against the side surface of the pulley groove when the belt is loosened is formed on both portions.

(Operation) When the clutch is turned off by reducing the distance between the shaft centers of both pulleys, the drive belt loosens, the drive pulley and drive belt are released, and the power transmission from the drive source such as the engine to the drive belt does not occur. Be refused.

On the other hand, in the driven pulley, the drive belt contacts the inclined portion and is pressed against the pulley groove side surface of the driven pulley. As a result, the drive belt is braked, and the driven pulley, the cutter and the like are braked via the drive belt, and the cutter and the like stop quickly.

(Embodiment) FIG. 4 shows an example of an edge mowing machine provided with a belt drive device according to the present invention. First, the structure of the edge mowing machine will be briefly described. An engine 1 is mounted on the vehicle body, two rear wheels 2 and one front wheel 3 are provided, and a vertically oriented cutter 7 is provided on the left front side of the vehicle body.
Drive shaft (engine output shaft) via belt drive 9
It is interlockingly linked to 13. A clutch lever 6 is provided on the rear handle 5, and the clutch lever 6 is connected to a control lever 23 of a belt driving device 9 via a control rod 26.

FIG. 1 is a vertical cross-sectional side view of a belt driving device 9 according to the present invention, in which a driven pulley 12 is arranged at a front lower position of a driving pulley 11 fixed to a driving shaft 13, and the driven pulley 12 is a horizontal driven member. The driven shaft 15 is fixed to one end of the drive shaft 15, and the driven shaft 15
It is rotatably supported by. The cutter 7 is fixed to the other end of the non-driving shaft 15.

A rod 18 extending rearward is fixed to the bearing 17, and the rod 18 is inserted and supported in a cylindrical swing arm 20 so as to be slidable in the length direction, and is contracted between the bearing 17 and the swing arm 20. The urging spring 21 urges the rod 18 forward, that is, in the direction of increasing the distance between the two pulleys. A stopper pin 22 is fixed to the rear end of the rod 18.

The swing arm 20 includes a support shaft 25 located below the drive shaft 13.
Is swingably supported in the up-down direction about a swing center and is coupled to an L-shaped control lever (bell crank) 23 so as to swing integrally via a boss portion 25a and the like.

A return spring 27 that biases the control lever 23 upward is engaged with the front end portion of the control lever 23, and an upper end portion of the return spring 27 is engaged with, for example, a bracket of the engine 1. The control rod 26 is pivotally connected to the lower end of the control lever 23.

The belt pulley cover is divided into a rear driving pulley cover 30 and a front driven pulley cover 31, which are each formed of sheet metal, and the driving pulley cover 30 is fixed to the engine 1 and the driven pulley. The cover 31 is fixed to the driven pulley bearing 17.

The driven pulley cover 31 has a generally semicircular front half portion that covers the outer periphery of the front half of the driven pulley 12, and generally linear extensions formed at both ends on the belt entrance / exit side. At the belt outlet A of the driven pulley cover 31, the third
As shown in the figure, an inclined portion 33 that slides and presses the drive belt 16 against the side surface of the pulley groove 35 when the belt is loosened is formed. The inclined portion 33 is inclined so as to come to the bearing 17 side as it goes outward in the radial direction.

The drive-side pulley cover 30 shown in FIG. 1 is formed in a substantially partial circle having a circumferential angle larger than 180 ° and covers the outside of the drive pulley 30, but when the clutch is off, the drive pulley 11 and the drive belt 16 are not covered. The edge portions 30a and 30b on the belt entrance / exit side are narrowed down so that they can be released. More specifically, the belt entrance / exit side edge portions 30a and 30b of the drive-side pulley cover 30 will be described.
Are located in the vicinity of the back surface of the belt on the belt tangent line, and the distance C between the end edge 30b on the belt inlet side and the drive belt 16
5 is set narrowly. The distance C3 between the drive pulley 11 and the drive side pulley cover 30 is wider than the distance C5 between the drive belt 16 on the inlet side and the end edge portion 30b, and gradually increases from the belt inlet side toward the rotational direction R side. The maximum is before the belt release point P2 on the belt exit side, and the belt wrapping space S is formed there. However, since the outlet side edge portion 30a is narrowed down as described above, the distance C4 between the edge portion 30a and the drive belt 16 is at least smaller than the distance C3 in the belt holding space S.

The operation will be described. As shown in FIG. 4, the clutch lever 6 is raised toward the front and engaged with the groove of the engaging plate 9, thereby
As shown in the figure, the control rod 26 is pulled backward, the swing arm 20 is lowered, the axial distance between both pulleys is expanded, and the clutch is turned on.

From the clutch-on state of FIG. 1, when the clutch lever 6 of FIG. 4 is tilted forward to loosen the control rod 26,
As shown in FIG. 2, the swing arm 20 is lifted by the elastic force of the return spring 27, whereby the axial distance between both pulleys is reduced and the drive belt 16 is loosened. At this time, since the drive belt 16 also rises, the back surface of the belt 16 comes into contact with the end portion 30a of the drive side pulley cover 30 on the belt outlet side and is braked, and the drive belt 16 is brought into contact with the end portion 30a. In the drive-side pulley cover 30, particularly in the holding space S, it spreads radially outward and is released from the drive pulley 11. It also contacts the inlet end 30b.

That is, the drive belt 16 is released from the drive pulley 11, and thereby the drive belt 16 is prevented from rotating around the drive pulley 11.

On the other hand, for the driven pulley cover 31, the drive belt 16
Loosens and tries to return to the shape at the time of manufacture, that is, to have an annular shape, so that it contacts the inclined portion 33 at the belt outlet portion A as shown in FIG. 3 and is slid against the side surface of the pulley groove 35. That is, when the driving belt 16 contacts the inclined surface 33 of the driven pulley cover 31 and the side surface of the pulley groove 35, the driving belt 16 and the driven pulley 12 are braked, and the cutter 7
Quickly stops the rotation of.

(Other Embodiment) The inclined portion may be formed at the belt entrance portion of the driven side pulley cover. It can also be formed at both entrances and exits.

(Effect of the Invention) According to the present invention as described above, the inclined portion for slidingly pressing the belt to the pulley groove side surface when the belt is loosened is formed in the belt outlet portion or the inlet portion or the inlet / outlet portion of the driven side pulley cover. Therefore, the driven pulley and the drive belt can be quickly stopped when the clutch is off, without providing a new additional brake component.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a belt driving device to which the present invention is applied in a clutch-on state, FIG. 2 is a vertical sectional side view of the same belt driving device in a clutch-off state, and FIG. 3 is a longitudinal sectional view of FIG. III-III sectional enlarged view, FIG. 4 is a side view of a mower equipped with the belt drive device of FIG. 1, FIG. 5 is a conventional belt drive device, and is a sectional view of the same portion as FIG. is there. 1 ...
… Engine, 11 …… Drive pulley, 12 …… Driven pulley,
16 …… Drive belt, 17 …… Driven pulley bearing, 18 …… Rod, 20 …… Swing arm, 21 …… Biasing spring, 30 ……
Drive side pulley cover, 30a, 30b ... edge, 31 ... driven side pulley cover, 33 ... inclined part

Claims (1)

[Scope of utility model registration request] 1. A drive pulley, a driven pulley, a drive belt hung on both pulleys, and a swing arm having a swing fulcrum at a position different from a rotation center of the drive pulley.
A rod that is slidably supported by the swing arm and that supports the bearing of the driven pulley, a spring that urges the rod in a direction to increase the axial distance between the pulleys, and a belt pulley cover In a belt drive device that changes the shaft center distance of the pulley by swinging operation to turn the clutch on and off, place the drive belt on the belt outlet or inlet or outlet of the driven pulley cover at the time of belt loosening. A clutch / brake device for a belt drive device, wherein an inclined portion that slides and presses is formed on a side surface of the pulley groove.