JPH0587202A - Variable speed pulley device - Google Patents

Abstract

PURPOSE:To restrain direct contact of an engaging member engaged with a torque cam with the rear side of a cam face so as to reduce operating force when a pulley is opened due to reduced thrust from outside in a variable speed pulley device having a torque cam mechanism by providing a notch in the rear face of the cam face of a torque cam groove. CONSTITUTION:A torque cam mechanism is provided for generating thrust in the closing direction of a variable speed pulley 6 by pressing a movable sheave 9 onto a fixed sheave 7 by relative rotation of a movable sheave 9 of the pulley 6 constituted of variable pulleys and a rotation shaft 1. On the rear side of a cam face 10a of a torque cam groove 10, a notch 26 is provided so that it does not touch a torque pin 11. By this constitution, when the pulley 6 is opened and thrust to a belt B by a transmission mechanism 16 is reduced and at the time of reversion of the torque transmission direction such as engine braking, the torque pin is made not to touch the back of the cam face 10a of the torque cam groove 10 so as to reduce operating force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change pulley device for changing speed by changing the pulley diameter of a variable pulley around which a transmission belt is wound, and more particularly, to a movable sheave by utilizing a torque difference from a rotary shaft. The present invention relates to an improvement of a device provided with a torque cam mechanism that moves in the axial direction.

[0002]

2. Description of the Related Art Conventionally, this type of speed change pulley device has been
For example, it is widely used in power transmission systems with relatively low loads such as transmissions in agricultural machines and light vehicles. This transmission is, for example, a fixed sheave fixed to the rotary shaft so as to rotate integrally and immovably in the axial direction, and a rotatably and axially movably supported by the rotary shaft, and between the fixed sheave, A variable speed pulley including a movable sheave that forms a belt groove having a V-shaped cross-section around which the belt is wound is provided, and the pulley diameter (effective radius of the belt groove) is changed by bringing the movable sheave into and out of contact with the fixed sheave by a speed change mechanism. By doing so, the gear ratio is switched to a low speed state or a high speed state.

In such a speed change pulley device, the torque difference between the rotary shaft and the movable sheave that can rotate relative to the rotary shaft is utilized to urge the movable sheave in the direction of approaching the fixed sheave. A torque cam mechanism is known in which a thrust force applied from the outside can be reduced by a speed change mechanism.

In this torque cam mechanism, for example, as shown in FIG. 5, the boss portion 10 of the movable sheave 109 in the pulley is used.
Torque cam groove 11 that has a cam surface 110a that is spirally inclined with respect to the rotation axis on the inner surface (or outer surface of the rotation shaft) 9a.
While forming 0, the boss portion 109 of the movable sheave 109
On the outer surface of the rotary shaft (or the inner surface of the boss portion 109a of the movable sheave 109) corresponding to the inner surface of a, a torque pin 111 that slidably engages with the torque cam groove 110 is provided so as to project the torque between the rotary shaft and the movable sheave 109. Due to the relative rotation in the predetermined direction due to the difference, the torque pin 111 moves in the torque cam groove 1
The cam surface 110a of 10 is pressed to move the movable sheave 109 in a direction approaching the fixed sheave (leftward in FIG. 5).

[0005]

However, in the above-mentioned conventional one, when the thrust due to the speed change mechanism is lost and the movable sheave 109 separates from the fixed sheave to open the pulley, the cam surface 110a of the torque cam groove 110 is pressed until then. After the torque pin 111 that had been detached from the cam surface 110a,
It comes to slide in the groove 111 while hitting the back side, and there is a problem that the sliding resistance at that time is large and the operation force becomes heavy accordingly. That is, suppose now that FIG.
As indicated by the solid line in FIG.
When the belt B is transmitted between the fixed and movable sheaves 107, 109 in a state in which the belt B is distorted by the side pressure P by a constant amount A, if the belt thrust from the movable sheave 109 due to the speed change mechanism is lost, the belt B is the same. The movable sheave 109 is pushed back by the thrust P by the restoring force of the strain as shown by the phantom line in the figure. FIG. 7 shows the relationship of forces acting between the torque cam groove 110 and the torque pin 111 when the movable sheave 109 receives the thrust P from the belt B. The thrust P is P1 depending on the twist angle θ1 of the torque cam groove 110. , P2. However, since the movable sheave 109 is in a state in which the speed change mechanism for fixing the position thereof is removed, the movable sheave 109 moves by the resultant force of the reaction force P1r of the component force P1 and the component force P2, and the torque pin 111 relatively moves the torque cam groove. It moves in the θ2 direction within 110. As a result, the torque pin 111 causes the cam surface 1 of the torque cam groove 110 to move.
It slides while pressing the back side of 10a.

In addition, when the torque transmission direction between the rotary shaft and the movable sheave 109 is reversed due to engine braking or the like while the torque cam mechanism is operating, the torque cam mechanism applies a thrust force in the direction to open the pulley. Since it is generated, the operating force suddenly becomes heavy, and if the operating force is insufficient, the pulley will open naturally.

The present invention has been made in view of the above points, and an object thereof is to improve the structure of the torque cam groove in the torque cam mechanism so that the engagement can be achieved when the pulley is opened or when the torque transmission direction is reversed. The purpose is to prevent the member from coming into contact with the back side of the cam surface to reduce the operating force.

[0008]

In order to achieve this object, in the invention of claim 1, the rear surface side of the cam surface is cut out in the torque cam groove.

That is, according to the present invention, a fixed sheave fixed to the rotary shaft integrally with the rotary shaft and immovably in the axial direction,
It is rotatably supported on the rotating shaft and movable in the axial direction.
In a speed change pulley device including a movable sheave that forms a belt groove having a V-shaped cross section around which a belt is wound, the speed change pulley device including the inner surface of the boss portion of the movable sheave or the outer surface of the rotary shaft. On one side, a torque cam groove having a cam surface is arranged spirally with respect to the rotation axis, and on the other side, an engaging member slidably engaged with the torque cam groove is provided so as to protrude from the rotation axis. The engaging member presses the cam surface of the torque cam groove as the movable sheave rotates relative to the movable sheave in a predetermined direction, and the movable sheave moves in a direction approaching the fixed sheave.

Further, a notch portion which is notched in the circumferential direction is formed on the back side of the cam surface in the torque cam groove.

According to the second aspect of the invention, specifically, the cutout portion is cut out so as to have a side surface extending in parallel with the rotation axis.

According to the third aspect of the invention, the notch is formed so as to be symmetrical with the cam surface with respect to the plane passing through the rotation axis.

[0013]

With the above-described structure, in the invention of claim 1 or 2, the torque cam groove is notched on the rear side of the cam surface. Therefore, when the pulley is opened due to a decrease in thrust, the engaging member has a notched portion on the rear side of the cam surface. Through which the engaging member slides in the torque cam groove, the engaging member does not move while coming into contact with the cam surface rear surface, and the engaging member moves smoothly.
Therefore, the operating force can be reduced.

Further, even when the torque transmission direction between the rotary shaft and the movable sheave is reversed due to engine braking or the like, the engagement member does not come into contact with the cam surface rear surface side.
Light operating force can be maintained and the pulley does not open.

According to the third aspect of the present invention, since the notch is formed so as to be symmetrical with the cam surface with respect to the plane passing through the axis of rotation, two cam surfaces are formed in the torque cam groove. By using one of the two cam surfaces as the original cam surface, the function of the torque cam mechanism can be obtained regardless of the direction of rotation of the movable sheave, and versatility is enhanced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 2 and 3 show the overall construction of Embodiment 1 of the present invention, in which 1 is a rotary shaft on the drive side in a speed change pulley device, and the rotary shaft 1 is a rotary shaft main body 2; A cylindrical roller mount support part 3 arranged at the tip thereof, a cylindrical sleeve 4 concentrically fitted between the rotary shaft body 2 and the roller mount support part 3, and a roller mount support. Part 3
Is attached to the rotary shaft main body 2 in a rotationally integrated manner.

A speed change pulley 6 is supported at the tip of the rotary shaft 1. This speed change pulley 6 has fixed and movable sheaves 7 and 9 in the form of flanges arranged on the rotary shaft 1 so as to face each other. The fixed sheave 7 is provided at the base end side of the rotary shaft main body 2 with a boss portion 7a. It is fixed by a key 8 so as to rotate together and not to slide. On the other hand, the sleeve 4 located on the tip end side of the rotary shaft 1 is non-rotatably fitted outside by the key 8, and the movable sheave 9 is formed on the outer circumference of the sleeve 4, the torque cam groove 10 formed on the inner peripheral surface of the boss portion 9a, By engaging torque pins 11 and 11 projecting on the outer circumference of the sleeve 4 with 10 respectively, they are coupled and supported so as to be slidable in the axial direction and rotatable relative to the rotary shaft 1. As shown in FIG. 1, each of the torque cam grooves 10 is arranged on the inner surface of the boss portion 9a of the movable sheave 9 basically in a spiral shape with respect to the rotation axis, and has a cam surface 10a on one side thereof. As the shaft 1 rotates relative to the movable sheave 9 in the driving direction, the torque pin 11 presses the cam surface 10a of the torque cam groove 10 to move the movable sheave 9 in a direction approaching the fixed sheave 7. ing.

A belt groove 12 having a V-shaped cross section is formed between the sheaves 7 and 9, and a V-belt B is wound around the belt groove 12. The movable sheave 9 of the pulley 6 is fixed to the fixed sheave 7. The gear ratio is changed by changing the pulley diameter by contacting and separating with respect to.

A bearing 14 is mounted on the sleeve 4 between the sheaves 7 and 9, and an outer race of the bearing 14 is arranged at the bottom of the belt groove 12 so as to rotate freely with respect to the sleeve 4 (rotary shaft 1). The body 15 is configured, and when the pulley 6 is opened to the maximum,
By transferring the belt B to the idle body 15, a neutral state in which the transmission between the belt B and the pulley 6 is cut off is achieved. Reference numeral 13 is a recess formed on the inner peripheral side of the belt groove 12 of the movable sheave 9 so as not to interfere with the bearing 14 when the pulley 6 is closed.

A cam mechanism 16 for bringing the movable sheave 9 into and out of contact with the fixed sheave 7 is provided on the back side of the movable sheave 9 in the pulley 6. The cam mechanism 16 has a cylindrical cam 18 which is externally fitted and supported on the outer periphery of the boss 9a of the movable sheave 9 via a bearing 17 so as to be relatively rotatable and axially movable integrally. A pair of cam surfaces 19 and 19 are formed on the end surface of the cam 18 on the side opposite to the pulley 6 at equal angular intervals (180 ° intervals) in the circumferential direction. Inclining away from the pulley 6 in the direction of rotation. Further, a rotation lever 20 is provided on the outer periphery of the cam 18 so as to integrally rotate, and the cam 18 is rotated around the rotation shaft 1 by operating the rotation lever 20.

An annular roller mount 21 is supported at the tip of the roller mount support 3 of the rotary shaft 1 so as to be rotatable relative to the rotary shaft 1 via a bearing 22. A fixed arm 23 extending in the radial direction is integrally fixed to the outer periphery of the roller mount 21, and the tip of the fixed arm 23 is fastened by a fixed body (for example, a case of a transmission) not shown. As a result, the roller mount 21 is fixed so as not to rotate around the rotating shaft 1 and to move axially. A pair of pins 24, 24 extending in the radial direction are integrally mounted on the outer periphery of the roller mount 21 in correspondence with the cam surfaces 19, 19 of the cylindrical cam 18, respectively. The head side of each pin 24 projects from the roller mount 21, and the cam 18
A roller 25 for a cam that abuts on each of the cam surfaces 19 and rolls is rotatably supported. Then, the rotating lever 2
The cylindrical sheave 18 is rotated around the rotating shaft 1 in the direction opposite to the rotating direction by 0, and the cam roller 25 is rolled on each of the cam surfaces 19, thereby moving the movable sheave 9 in the axial direction. The fixed sheave 7 is made to approach the fixed sheave 7, and the effective radius of the belt groove 12, that is, the pulley diameter of the pulley 6 is increased.

Further, as a feature of the present invention, as shown in FIG. 1, on the rear side of the cam surface 10a of the torque cam groove 10 in the boss portion 9a of the movable sheave 9, the rear side is notched in the circumferential direction. Is formed so that the notch 26 has a side surface 26a extending parallel to the rotation axis.

Therefore, in this embodiment, the cam mechanism 1
6 rotates the cylindrical cam 18 around the rotating shaft 1 by operating the rotating lever 20 in FIG.
The rollers 25 and 25 roll on the rollers 9 and 19, respectively, and the cam contact between the cam surface 19 and the roller 25 causes the movable sheave 9 to move in the axial direction to come into contact with and separate from the fixed sheave 7.
The pulley diameter is changed and the gear ratio is switched.

That is, in order to close the pulley 6 and bring it to a high speed state where the pulley diameter is increased, the rotary lever 20 is rotated toward the Hi position shown in FIG. As the cam 18 rotates, each cam surface 19 is pushed by the roller 25, so that the cam 18 and the movable sheave 9 connected thereto via the bearing 17 move in the axial direction to move the fixed sheave 7.
, The movable sheave 9 approaches the fixed sheave 7 to the maximum, the pulley 6 closes, and the high speed state is achieved.

In order to open the pulley 6 to reduce the diameter of the pulley to a low speed state, the rotation lever 20 is rotated toward the Lo position shown in FIG. The pressing force of the roller 25 against 19 disappears, the thrust force from the belt B causes the movable sheave 9 to move in the axial direction and separate from the fixed sheave 7, and the movable sheave 9 is separated from the fixed sheave 7 to the maximum extent to open the pulley 6. , It becomes a low speed state.

In such a transmission load state, a torque difference acts between the rotating shaft 1 and the movable sheave 9, and the rotating shaft 1 rotates relative to the movable sheave 9 in the driving direction due to this torque difference. Accordingly, the torque pin 11 presses the cam surface 10a of the torque cam groove 10 to move the movable sheave 9 in a direction of approaching the fixed sheave 7, and the biasing force reduces the thrust from the outside by the cam mechanism 16.

At this time, the cam surface 10 of the torque cam groove 10
Since the notch 26 is formed on the back side of the a, when the pulley 6 is opened due to the reduction of the thrust from the cam mechanism 16, as shown in FIG.
Also, even if the torque pin 11 moves toward the rear side of the cam surface 10a according to the principle described with reference to FIG.
Comes to move in the torque cam groove 10 through the notch 26 without directly contacting the back side of the cam surface 10a, and the torque pin 11 is smoothly moved, so that the operating force can be reduced. ..

Further, the rotary shaft 1 is provided by the engine brake or the like.
Even if the torque transmission direction between the movable sheave 9 and the movable sheave 9 is reversed, the torque pin 11 causes the cam surface 1 of the torque cam groove 10 to move.
Since the torque cam mechanism does not make contact with the back surface of the pulley 0a, thrust does not occur in the direction of opening the pulley 6, and sudden increase in the operating force is prevented, and a predetermined gear ratio can be maintained.

When the clutch is turned off to disconnect the connection between the pulley 6 and the belt B, the rotating lever 20 is positioned at the N position (neutral position) shown in FIG. Along with this rotating operation, the movable sheave 9 is further separated from the fixed sheave 7 by the thrust from the belt B, the belt B rides on the idle body 15 between the sheaves 7 and 9, and the connection between the belt B and the pulley 6 is cut off. The neutral state is reached.

(Embodiment 2) FIG. 4 shows Embodiment 2 of the present invention (note that the same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted). Part 2
6 is cut out so as to have a side surface 26a extending parallel to the rotation axis, while the cutout 26 'is cut out so as to be symmetrical with the cam surface 10a with respect to the plane passing through the rotation axis. A cam surface 26 symmetrical to the cam surface 10a with respect to the plane
b'is formed.

In this embodiment, the notch portion 26 'is notched so as to be symmetrical to the cam surface 10a with respect to the plane passing through the axis of rotation, so that the torque cam groove 10 has the cam surface 10a.
And the cam surface 26b 'in the cutout portion 26' are formed. As a result, regardless of the direction of rotation of the rotary shaft 1, the cam surfaces 10a and 26 can be rotated.
By using one of b'as the original cam surface, the function of the torque cam mechanism can be obtained, and the versatility is enhanced.

In each of the above embodiments, the torque cam groove 10 is formed on the inner surface of the boss portion 9a of the movable sheave 9, and the torque pin 11 is provided on the outer surface of the rotary shaft 1. However, conversely, the rotary shaft 1 is formed.
The torque cam groove is formed on the outer surface, and the boss portion 9 of the movable sheave 9 is formed.
A torque pin may be provided so as to project on the inner surface of a, and the same effect as that of each of the above embodiments can be obtained.

[0034]

As described above, according to the first or second aspect of the present invention, the relative rotation between the movable sheave and the rotary shaft of the speed change pulley pushes the movable sheave against the fixed sheave, and the thrust is applied in the direction in which the pulley is closed. In a speed change pulley device that has a torque cam mechanism to generate, when the pulley opens due to a decrease in thrust from the outside due to the notch on the cam surface rear side of the torque cam groove, the engaging member engaging the torque cam is It is possible to reduce the operating force by suppressing direct contact with the side, and also to reduce the operating force when the torque transmission direction between the rotary shaft and the movable sheave is reversed due to engine braking etc. Can be maintained.

According to the third aspect of the present invention, since the notch on the rear side of the cam surface is cut out so as to be symmetrical with the cam surface with respect to the plane passing through the rotation axis, two cam surfaces are formed in the torque cam groove. As a modified form, the function of the torque cam mechanism can be obtained regardless of the direction of rotation of the movable sheave,
The versatility can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a movable sheave showing a torque cam groove according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a speed change pulley device.

FIG. 3 is a side view of a transmission pulley device.

FIG. 4 is a view corresponding to FIG. 1 showing a second embodiment.

FIG. 5 is a view corresponding to FIG. 1 showing a conventional example.

FIG. 6 is a cross-sectional view showing a strained state of the belt when a lateral pressure is applied from the pulley.

FIG. 7 is a diagram showing a relationship between forces acting between a torque cam groove and a torque pin when a movable sheave receives a thrust force from a belt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotating shaft 6 ... Speed change pulley 7 ... Fixed sheave 9 ... Movable sheave 9a ... Boss part 10 ... Torque cam groove 10a ... Cam surface 11 ... Torque pin (engaging member) 16 ... Cam mechanism (speed change mechanism) 26, 26 '... Notch Part 26a ... Side surface 26b '... Cam surface

Claims (3)

[Claims] 1. A belt between a fixed sheave fixed to a rotary shaft so as to rotate integrally and immovably in the axial direction, and a fixed sheave rotatably and axially moveable on the rotary shaft, between the fixed sheave. In a speed change pulley device including a speed change pulley formed with a movable sheave that forms a belt groove having a V-shaped cross section around which is wound, one of the inner surface of the boss portion of the movable sheave and the outer surface of the rotary shaft is
A torque cam groove having a cam surface is arranged spirally with respect to the rotation axis, while an engaging member slidably engaged with the torque cam groove is projected on the other side.
With the relative rotation of the rotary shaft and the movable sheave in a predetermined direction, the engagement member presses the cam surface of the torque cam groove so that the movable sheave moves toward the fixed sheave. The transmission pulley device has a notch formed in the circumferential direction on the back side of the. 2. The transmission pulley device according to claim 1, wherein the cutout portion has a side surface extending parallel to the rotation axis. 3. The transmission pulley device according to claim 1, wherein the notch is notched so as to be symmetric to the cam surface with respect to a plane passing through the rotation axis.