JPS5827152Y2 - variable speed pulley device - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of a speed change pulley device and a speed change pulley device that utilizes a centrifugal clutch.It prevents rattling of the shoe that occurs during speed changes, and at the same time reduces the noise generated during speed changes. The purpose is to suppress it.

Recently, a speed change Fourie device using a centrifugal clutch shown in FIGS. 1 and 2 has been disclosed.

As shown in the figure, this speed change pulley device includes a rotating base 1 that is fixed with a key or the like to a drive shaft that constantly rotates to receive power, such as the rotating shaft of an internal combustion engine, and a bearing portion 5a on the outer periphery of the rotating base 1. The drum 3 is rotatably mounted via a bearing portion 5b and constitutes a large pulley having a belt groove 2a, and the drum 4 is rotatably mounted via a bearing portion 5b and constitutes a small pulley having a belt groove 2b. .

The rotating base 1 is provided with a centrifugal clutch section 6 and a one-way clutch section 7, and the centrifugal clutch section 6 is connected to the rotating base 1.
The connection between the drum 3 and the drum 3 is controlled by the rotational speed, and the one-way clutch section 7 is arranged so as to transmit power only in the direction from the rotating base 1 to the drum 4.

The centrifugal clutch section 6 includes a swinging arm 10 that is rotatable about a shaft 9 provided on a bearing section 8 of the rotating base 1, and a swinging arm 10 that is attached to one end of this arm 10 with a screw 20 or the like, and has a specific gravity lower than the arm 10. A power transmission shoe that is rotatable around a dog weight 11 and a shaft 12 as a fulcrum provided at the other end of an arm 10 and is covered with a lining having an arcuate friction surface along the inner wall of a drum 3. 13 and arm 10
The spring 14 is provided between the arm 10 and the rotary base 1 on the shaft 12 side of the drum 1 and gives the arm 10 the ability to rotate in the direction of pressing the shoe 13 against the inner wall of the drum 3.

A pin 15 is provided at the end of the arm 10 on the side where the shaft 12 is provided, a pin 17 is also provided at one end 1a of the rotating base 1, and the spring 14 is disposed between the pin 15. The cap 16 also serves as a spring seat.
The pin 15 is in contact with the pin 17 through the cap 18 .

The rotation base 1 is provided with a stopper 21 that regulates the displacement of the weight 11 and the arm 10, and a locking piece 22 that engages with the stopper 21 is provided at one end of the weight 11, and the arm 10 and the drum 3 of the weight 11 are provided with a locking piece 22 that engages with the stopper 21. Contact with the inner wall is prevented.

Note that the arm 10 and the weight 11 may be integrally molded.

Furthermore, a hollow portion 23 is formed in the arm 10 for the purpose of reducing weight and separating the center of gravity acid layer from the fulcrum 9 as much as possible.

The one-way clutch section 7 is connected to wedges 25 arranged at equal intervals on the outer periphery of the cylindrical body 24 that protrudes from the rotating base 1, and the wedges 25 (/'i It is placed on the guide piece 27 that is positioned.

A blocking piece 29 is provided at the = end of the guide piece 27.
9 can freely come into contact with the stopper 28, and excessive displacement of the guide piece 2T is prevented.

The wedge 25 is made of a material with a high coefficient of friction, and the inclined surface side of the guide piece 27 is treated with a material that is easy to slip.

When the guide piece 27 moves outward along the inclined surface, the wedge 25 is strongly pressed against the inner wall of the drum 4, and power is transmitted.

FIG. 3 is a schematic diagram for using the pulley device having the above configuration, and the same parts as in FIGS. 1 and 2 are denoted by the same reference numerals.

In the figure, there is a gap between one groove 2a of a drum 3 disposed on a rotating base fixed to a drive shaft and one groove 31a of a pulley 31 of the same diameter and integrated with an intermediate rotating shaft 30. A belt 36a is hung thereon, and a bell 36b is also hung between one of the grooves 2b of the drum 4 and the other groove 31b of the pulley 31.

When actually driving driven members using this two-stage pulley device, the intermediate rotating shaft 30 is connected to the rotating shafts of all driven members, and all driven members are directly driven by two belts. You can also use drum 3 as shown in Figure 3.
or the other groove 2b of the drum 4 and the pulley 35 provided on the rotating shaft 32, 33° 34 of the driven member.
A belt may be directly or indirectly hung between the grooves a, 35b, t, and 35c to transmit power.

In the above configuration, when the rotational speed of the drive shaft is low, the elastic force of the spring 14 overcomes the rotational force of the arm 10 based on the centrifugal force against the weight 11, and the friction surface 13a of the power transmission shoe 13 moves toward the drum 3. The base 1 and the drum 3 rotate integrally through the shoe 13 of the base 1 and the drum 3.

Therefore, the intermediate rotating shaft 30 rotates depending on the rotation of the large diameter drum 3.

Furthermore, the rotational force of the large diameter drum 3 is applied to the small diameter drum 4 by the belt 36a.

36b, transmitted via the intermediate rotating shaft 30.

In this case, the drum 4 rotates at a higher speed than the cylindrical body 24 due to the rotational force transmission path, so the one-way clutch section 7 does not transmit power and the cylindrical body 24 and the drum 4 rotate independently.

Next, when the rotational speed of the drive shaft reaches a set value (preset based on the weight of the weight 11, the length of the arm 10, the strength of the spring 14, etc.), the centrifugal force due to the weight 11 acts on the elastic force of the spring 14. As a result, the arm 10 rotates and the shoe 13 separates from the inner wall of the drum 3, so that the rotation base 1 and the drum 3 are uncoupled.

Due to the above operation, the transmission of power from the drum 3 to the drum 4 via the bells 36 a and 36 b is interrupted, so that the rotation speed of the drum 4 is lower than the rotation speed of the cylinder 24 on the rotating base 1. Since the speed is about to become low, the wedge 25 is strongly pressed against the inner wall of the drum 4 together with the guide piece 27, so the drum 4 is connected to the rotating base 1 via the wedge 25, and the intermediate rotating shaft 30 is connected to the small diameter drum 4. Rotates depending on the rotation of .

At this time, the drum 3 also has belts 36a and 36b.

Rotates (idls) in response to the rotational force of the pulley 31a
.

That is, when the rotational speed of the drive shaft increases and reaches the set rotational speed, the rotational speed transmitted to the intermediate rotating shaft 30 is automatically switched by the action of the centrifugal clutch and becomes lower than before switching.

Therefore, if the switching point of this speed change pulley device is adjusted to the requirements of the driven member that is actually being driven, unnecessary movement of the driven member can be suppressed, and moreover, excessive driving can be prevented, and the driven member In addition to protecting the drive shaft, the load on the drive shaft can be reduced.

Note that when the rotational speed of the drive shaft decreases, the operation opposite to the above is performed.

The above configuration can be shown as a simplified configuration diagram as shown in FIG. 4, showing the positional relationship among the shoe 13, the arm 10, and the large diameter drum 3.

In the figure, O is the center of the rotating base, A is the fulcrum of the arm 10 (axis 9), and B is the fulcrum of the mounting position of the shoe 13 (axis 12).
, and the angle formed by the line segment l connecting the fulcrum B (axis 12) of the shoe 13 and the fulcrum A (axis 9) of the arm 10 and the line segment m connecting the fulcrum B and the central axis 0 of the rotating base 1 is β. Toshi, Shoe 1
3 is in contact with the inner wall of drum 3, the drag force that acts is N,
The friction force of the shoe 13 is expressed as Ff, and the resultant force of Ff and N is expressed as R1. The angle of the resultant force with respect to the drag force N, that is, the friction angle of the shoe 13 is expressed as φ.

Next, an explanation will be given based on the relationship shown in FIG. 4 above and calculation unity.

(The details of the calculations are not described in this specification.

) If the relationship between β and φ is β<φ, then the characteristic shown in FIG.

This characteristic is such that the switching speed increases as the load increases, and since it is a characteristic that slippage does not easily occur between the drum 3 and the shoe 13 at the time of switching, the shoe 13 is not suddenly coupled to the drum 3. means,
This situation becomes more pronounced as the difference between β and φ increases.

This results in an intermittent sound occurring at the time of switching.

Therefore, the relationship β<φ cannot be adopted in terms of design.

If β = φ, the same characteristic will become the characteristic that the rotation speed will not change even if there is a rise load fluctuation in the vertical direction as shown in Fig. 5, which is ideal, but at the time of design, β =
Even if it is set to φ, it is difficult to obtain the characteristics described above in actual commercialization due to the accuracy of each part, wear of the shoe 13, variation in the friction coefficient of the shoe 13, etc.71
1) The characteristic is that the mouth is tilted to either the left or right.

Therefore, when tilting to the right, the same result as when β<φ is obtained.

Therefore, even though β-φ is ideal, it cannot be adopted in commercialization due to variations in parts.

If β>φ, the same characteristic is shown by C in FIG.

This characteristic is a characteristic in which the switching speed becomes lower as the load increases, and slippage is likely to occur between the drum 3 and the shoe 13 at the time of switching, so the shoe 13 is suddenly coupled to the drum 3. This means that it is advantageous in terms of noise countermeasures, and this situation becomes more pronounced as the difference between β and φ increases.

Therefore, although this characteristic cannot be said to be an ideal characteristic either, by bringing β closer to φ, the characteristic can be approximated to β=φ.

From the above points, the characteristic β>φ is adopted in this case.

However, if this β is changed to a large value, the shoe 13 will slide more than the drum 3 at the time of switching, and the switching rotation speed will change depending on the magnitude of the load.

In addition, the shoe 13 may slip and burn out.

Therefore, it is not allowed to increase this β too much.

When the maximum allowable range of β was experimentally determined from this viewpoint, the conclusion that β<1.5φ was obtained.

In this range, almost no slippage occurs, and there is no change in the switching rotation speed during gear shifting, no burnout of the shoes, etc., which are problems in practice.

Therefore, when satisfying the relationship φ×β<1.5φ,
This is advantageous in terms of noise countermeasures, as well as in terms of speed change operation and reliability.

[Brief explanation of the drawing]

1 and 2 are a plan view and a sectional view showing an example of a speed change pulley device, FIG. 3 is a simplified configuration diagram showing how the speed change pulley device is used, and FIG. 4 is a simplified view of the speed change pulley device. The figure shown in FIG. 5 is a characteristic diagram showing an embodiment of the variable speed pulley device according to the present invention. 1... Rotating base, 3, 4... Large and small drums, 6... Centrifugal clutch section, 7... One-way clutch section, 9.12... ...Axis, 10.
... Arm, 11 ... Weight, 13.
... Shoe 14 ... Spring.

Claims (1)

[Scope of utility model registration request] A rotating base fixed to the drive shaft, a large diameter drum constituting a large pulley rotatably attached to the rotating base, and a small diameter drum constituting a small pulley, pivoted to the rotating base side and exerting centrifugal force. an arm whose one end is separated from the inner wall of the large-diameter drum by rotating; a shoe for power transmission that is pivotally connected to one end of the arm and faces the inner wall of the large-diameter drum;
an elastic member that applies a force to the arm in the direction of pressing the shoe toward the large-diameter drum; and a one-way clutch that is disposed between the rotating base and the small-diameter drum and only transmits power from the rotating base to the small-diameter drum. and an intermediate rotating shaft connected to the large pulley and the small pulley via a belt, and a line segment connecting the fulcrum B of the shoe and the fulcrum A of the arm, the central axis O of the rotating base, and the fulcrum B of the shoe. and the friction angle φ of the shoe when the shoe contacts the inner wall of the large-diameter drum, the relationship φ×β<1.5φ is established. pulley device.