JPS5840374Y2 - Speed change pulley for power transmission - Google Patents

Description

[Detailed description of the invention] This invention relates to a speed change pulley used in drive devices for automobiles, motorcycles, agricultural machinery, and other general industrial machinery, in which one of a pair of opposing ■-shaped pulley pieces is fixed to a shaft. At the same time, a stopper is attached to the side of the movable pulley piece, and a coil is formed so as to be constantly wound and loosened by the torque generated during running between the movable pulley piece and the stopper. A spring is inserted and locked, the movable pulley piece is pressed by the spring, and the speed change pulley is installed and formed so that the shaft and the pulley piece are coupled in the rotational direction via the spring, and the movable pulley piece is further pressed. Attach metal fittings,
By pressing the metal fitting with the arm through the bearing, power is transmitted while the belt is being driven, and the side of the movable pulley piece is appropriately suppressed or returned from the outside to move in the axial direction, and the movable pulley piece is moved in the axial direction. The purpose is to automatically adjust and change the effective diameter of the attached speed change pulley and the belt tension by the tension pulley or idler pulley.

A normal speed change pulley has a general configuration in which the belt is sandwiched between a pair of V-shaped speed change pulley pieces, and one or both pulley pieces prevent idling in the direction of rotation of the shaft by the pressing force of a spring on the side of the belt. A spline or keyway is formed in the thrust direction of the shaft so that one or both pulley pieces can move, but forming a spline or keyway in this way requires high material and processing costs. In addition to these problems, it also has the disadvantage that stress is generated in parts of the splines and gears, causing early breakage due to heat generation and wear due to friction in those parts.

On the other hand, Japanese Utility Model Publication No. 52-35412 proposes a ■-shaped variable speed pulley in which one movable pulley piece is attached via a coil spring. ,and,
Both ends of the spring have recessed holes in the movable leaf piece and the shaft cylinder attached to the side thereof, and the spring tip is bent and engaged with each recessed hole. The problem of frequent breakage of the engaging portion at the tip of the spring cannot be avoided due to the repeated forward and reverse rotation of the movable pulley piece.

Therefore, the inventor of the present invention has been planning to improve the speed change pulley for some time, and has repeatedly studied an improvement method that does not form the spline or keyway, and first proposed the use of a bushing. One or both of the movable pulley pieces can be freely moved in the thrust direction and rotational direction between the pulley piece and the shaft without having a fitting fixing part such as a spline or a keyway. , the contact part between each movable pulley piece and the shaft is made of cast iron or bird chrome plating with little seizure, and each movable pulley piece and a stopper placed and fixed on one side of the pulley are made of grooves or protrusions. A locking portion is provided, and a coil spring is inserted between the movable pulley piece and the stopper, and both ends of the spring are easily fitted and locked in the groove so that the spring always rotates in the direction of winding and loosening due to the rotation of the movable pulley piece. The authors proposed a speed change pulley that is fixed to the protrusion by contact pressure.

This invention is a further development of these series of attempts.
While the variable speed pulley transmits power between the movable pulley piece and the shaft via a spring, a pressing tool is additionally provided to press the movable pulley piece from the side of the pulley, thereby causing the movable pulley piece to By pressing the movable pulley pieces and distributing the pressing force, the required mechanical strength is relatively reduced and high loads can be handled.
It is characterized by a structure adapted to high-speed transmission applications.

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

Figure 1 shows an example of a speed change pulley according to the present invention.
In the figure, 1 is a ■-shaped pulley piece fixed to the shaft S by a bolt 12 through a key 13 on the outer periphery of the shaft, and further by another bolt 15 in the extended cylindrical part, and 2 is attached at a position opposite to the pulley piece 1. In the figure, the movable pulley piece 2 is an extension of the fixed pulley piece 1, so that the movable pulley piece 2 can rotate in the axial rotation direction and move in the thrust direction (axial direction). A stepped boss part forming the extended cylindrical part is formed on the outer surface of the movable pulley piece 3. A coil spring 4 having repulsive elasticity is interposed and pressed between the step part of the stopper 6 fixed by the stop ring 1T via the locking key 16, so that the movable pulley 2 can be moved in the axial direction. There is.

In the figure, 14 is an oil seal.

Although the spring 4 may be a round spring with a circular cross section, it is preferable to use a rectangular spring with a rectangular cross section in terms of durability and load transmission efficiency. Protrusions 5, 5' are provided on the inner surface of the stepped portion of the spring 4, and the spring 4 is locked by simply pressing the tip of the spring 4 against the protrusions 5, 5'.

However, this locking portion is not limited to the protrusions 5, 5', and may be formed by forming a groove and being fitted and pressed into the groove to be locked.

On the other hand, the spring 4 between the movable pulley 3 and the stopper 6 is surrounded, and
A metal fitting 7 for pressing a movable pulley piece is provided on the top so as to be movable in the rotation direction and the thrust direction, and a bearing 9 is installed on the outer step of this metal fitting 7, and an arm provided outside of the metal fitting 7 is installed. 8 from the outside in A and A' of the figure.
It is designed to be pressed by the parts.

Note that this arm 8 is attached to an arm support 11 for preventing rotation by a shaft 10.
' is a grease reservoir in the sliding part.

Next, to explain the operation of the speed change pulley in the above embodiment, first, when the belt 3 is suspended in the V groove formed by the two square boob pieces 1 and 2, and power is transmitted by the belt. , a rotating track is generated between the belt and the ■-shaped pulley pieces 1 and 2.

The torque is applied via the spring 4 by a spring locking part provided on the V-shaped pulley pieces 1 and 2, for example, a protrusion 5.
Further, the mechanism is such that the force is transmitted to the stopper 6 through a locking portion provided on the stopper 6 of the spring presser, such as a protrusion 5', and is transmitted to the shaft S through the key 16.

On the other hand, from the shaft side, the stopper 6 is closer to the shaft S.
Power can be transmitted as follows: → projection 5' → spring 4 → ■-shaped pulley side projection 5 → ■-shaped pulley pieces 1 and 2 → belt 3.

In the above power transmission, in addition to the adjustment by the spring pressing, a pressing fitting I for forcibly moving the movable pulley piece 2 is moved from the outside in the axial direction and rotational direction, and the movable pulley piece 2 is The unique feature of the present invention is that the effective diameter of the belt 3 in the V-groove can be changed as appropriate by pressing or returning the side by an appropriate amount and moving it in the axial direction.

In this case, when pressing from the outside, a bearing is interposed to eliminate direct friction during rotation between the suppression metal fitting 7 and an external pressing jig (not shown). It is pressed through the bearing.

Note that in the speed change pulley, the spring is twisted due to the torque generated in the movable pulley piece, and this twisting reduces the transmission efficiency when the rotational speed of the pulley changes.

Since this reduction in transmission efficiency tends to be worse as the torsion angle of the spring becomes larger, it is desirable to take this into consideration.

One example is that when Po is the lateral pressure required for the load generated when the belt runs, and P is the lateral pressure generated by the spring, P is 0.2 Po < P < 0.9 P.

It is preferable that the relationship is as follows.

If it is less than 0.2 Po, the torsion angle of the spring becomes large, reducing both the spring durability and the load transmission rate. On the other hand, if it is more than 0.9 Po, the force acting against the spring due to the effective tension while the belt is running increases. On the other hand, since the spring pressure increases, the pulley diameter does not change, making it virtually impossible to change gears.

Therefore, it can be said that it is preferable to use the side pressure generated by the spring as described above.

Figures 2 to 5 show various transmission mechanisms using the speed change pulley according to the present invention, and can be roughly divided into cases where the speed change pulley of the present invention is used as a drive pulley (see Figures 2 and 3). ), and when used as a driven pulley (Figures 4 and 5).

Each aspect will be explained below.

In the figure, the solid line indicates high speed, and the two-dot chain line indicates low speed.

(1) When the pulley of the present invention is used as the driving pulley Dr, (a) When the driven pulley 'JDn is a fixed pulley, it is supported by a spring 23 between the driving pulley Dr and the driven pulley Dn as shown in FIG. By providing the tension pulley 22 which is rotatable about the support pin 21, the movable pulley piece can be moved and the speed can be changed using the above-mentioned pressing metal fitting.

(0) When the driven pulley Dn is a general spring-type speed change pulley, this can be achieved by changing the effective diameter of the belt 3 in the groove of the speed change pulley Dr of the present invention as shown in FIG. Accordingly, the effective diameter of the belt in the spring-type speed change pulley Dr is changed to change the rotation ratio.

(2) When the bobbin of the present invention is used as a driven pulley Dn, (a) When the driven pulley Dr is a fixed pulley, as shown in FIG. 4, corresponding to FIG. By providing a tension pulley 22' that is rotatable about ', the movable pulley piece can be moved and the speed can be changed.

(b) When the drive pulley Dr is a known spring-type variable speed pulley, as shown in FIG. 5, (2) the effective diameter of the belt 3 is changed to change the rotation ratio;

Among the above systems, the so-called double speed pulley mechanism shown in Fuyume 1 and 2 is particularly suitable as a transmission mechanism using the speed change pulley of the present invention.

As explained above, the present invention transmits power between the movable pulley piece and the shaft via the spring, and furthermore, the movable pulley piece is held down from one side of the boob by a pressing tool via a bearing. , which has a variable configuration, and, compared to known systems that have been used in general practice, does not require integration with the shaft using splines or keys, and the sliding part between the shaft and the inner surface of the boob. At the same time, the presence of the pressing fitting disperses the force required to press the movable pulley piece, and a portion of the force required to press the movable pulley piece with the pressing tool is absorbed by the spring in advance. Since the sides of the movable pulley piece are pressed, the pressing force applied to the movable pulley piece pressing metal fittings can be reduced, and the presence of the bearing eliminates direct friction during rotation, making it structurally In addition to reducing the required mechanical strength, it is possible to provide a variable speed pulley that is inexpensive, suitable for high-load, high-speed transmission applications, is extremely practical, and has a remarkable effect on power transmission.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a speed change pulley according to the present invention, and FIGS. 2 to 5 are implicit explanatory diagrams showing examples of various transmission mechanisms using the speed change pulley of the present invention. 1... Fixed pulley piece, 2... Movable pulley piece, 3... V-belt, 4... Spring, 5, 5... Spring locking part (protrusion),
6...Stopper 7...Pulley piece press fitting, 8...Arm, 9...Bearing, 12, 15...Fixing bolt ,13,1
6...Key S...Axis.

Claims (1)

[Scope of utility model registration request] 1. A fixed pulley piece of a ■-shaped variable speed pulley consisting of a fixed pulley piece and a movable pulley piece is fixed to the shaft, and a movable pulley is mounted on the shaft with the shaft or the axially extending cylindrical part of the fixed pulley piece as a sliding axis. The piece is movably attached in the thrust direction and rotational direction, and a spring is inserted between the movable pulley piece and a stopper fixed to one side of the pulley via a key by a rotation locking part provided respectively. At the same time, on the axially extending cylindrical portion of the shaft or the fixed pulley piece, there is further provided a movable pulley piece pressing metal fitting that is movable in the rotational direction and the thrust direction for pushing out the movable pulley piece in the axial direction, and on the outside of the metal fitting. While forming a step and arranging the bearing, an arm is provided on the side of the step to press the bearing, and a groove between the two pulley pieces is adjusted according to the amount of movement of the metal fitting for pressing the movable pulley piece due to the bearing pressure of the arm. A variable speed pulley for power transmission, characterized in that the width is changed so as to change the effective winding diameter of the belt wound around the groove width. 2. The speed change pulley for power transmission according to claim 1, wherein the spring inserted between the movable pulley piece and the stopper is always wound in a direction that unwinds during power transmission. 3. The required lateral pressure P for the load that occurs when the belt runs
o, when the side pressure generated by the spring is P, the relationship between the two is 0.2Po<P<0.9P
A variable speed pulley for power transmission according to claim 1 or 2 of the utility model registration claim. 4. The variable speed pulley for power transmission according to claim 1, 2 or 3, wherein the spring is a square spring with a rectangular cross section.