JP3187723B2 - Power transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for transmitting power to an industrial machine requiring a large output such as a press machine or an injection molding machine.

[0002]

2. Description of the Related Art In general, a hydraulic servo system capable of obtaining a large output, such as a hydraulic cylinder, is used as a drive system for a large-capacity facility machine such as a press machine or an injection molding machine. There were difficulties. Therefore, as apparatuses capable of improving the speed performance of the drive system of these industrial machines, Japanese Patent Application Laid-Open Nos. 7-42808 and 7-213013 disclose such apparatuses.
There has been proposed a power transmission device as described in, for example, US Pat.

[0003] These power transmission devices include a drum which is rotated by transmitting the power of a flywheel, a transmission gear rotatably provided on the outer periphery of the drum, and which is rotated by a control motor, and which is opposed to the transmission gear. A drive gear provided coaxially with the drum and meshing with an output gear fixed to an output shaft; and a drive gear mounted on the outer periphery of the drum and having one end locked to the transmission gear and the other end being A helical traction coil engaged with the drive gear, so that a large power of the flywheel applied to the drum can be efficiently transmitted to the drive gear by utilizing a winding effect of the traction coil on the drum. It is.

In particular, according to this type of power transmission device, the rotation of the transmission gear is controlled by the control motor so that the winding force of the traction coil around the drum can be adjusted. The torque can be easily controlled.

[0005]

However, according to the above-mentioned conventional power transmission device, when power is transmitted to the output side through the traction coil, the wrapping force of the traction coil is small on the input side, and the power is transmitted between the traction coil and the drum. , A good lubricating state is maintained, but on the output side, the winding force of the traction coil becomes extremely large and seizure may occur.

[0006] In particular, the energy loss due to excessive adhesion of the traction coil to the drum is large, and at the beginning, slip occurs between the traction coil and the drum due to the tension applied to the traction coil, causing torque fluctuation on the output side. And there are many problems in terms of transmission efficiency and accuracy.

Therefore, in the present invention, when the power of the flywheel applied to the drum is transmitted to the output side using the winding force of the traction coil, excessive adhesion of the traction coil to the drum is prevented, and rotation of the drum is prevented. It is an object of the present invention to make it possible to transmit the motion efficiently in a pulse shape with a small slip.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a drum which is rotated by the power of a flywheel and which is rotatably provided on the outer periphery of the drum and which is rotated by a control motor. A transmission gear, a drive gear provided coaxially with the drum opposite to the transmission gear and meshing with an output gear fixed to an output shaft, and one end provided on the outer periphery of the drum and locked to the transmission gear at one end And a helical traction coil having the other end locked to the drive gear at the same time, wherein a mounting portion for fixing a pin to the outer periphery of the drum at a required interval in a circumferential direction thereof is provided. And the drive gear is fixed to the drive gear with a holder adjacent to the pin for rotatably holding another pin, and the pin is provided between the drum and the traction coil. Some of the peripheral surface be in is intended to provide a power transmission device is characterized in that so as to close contact with the inner peripheral surface of the traction coil in its axial direction.

[0009]

According to the present invention, when a pulling force directed in the same direction as the rotation direction of the inner drum acts on one end of the traction coil by rotating the transmission gear by the control motor, the traction coil exerts a high-pressure adhesion force. As a result, the power of the flywheel is rapidly wound around the inner drum to which the power is applied, and the power of the drum is transmitted to the drive gear.

In particular, at this time, the pin held by the holder generates a thrust for pushing the holder while rotating in the same direction as the drum due to the adhesive force of the traction coil. The thrust causes the drive gear to rotate in the same direction as the drum through the holder.

A similar phenomenon occurs in the pin fixed to the drum, and the thrust at this time becomes a force pulling the traction coil in the rotation direction of the drum.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic front view showing an example of the power transmission device according to the present invention.

In FIG. 1, reference numeral 1 denotes a flywheel which rotates in connection with a motor m shown in FIG. 2 via a timing belt or the like, and 2A and 2B receive power of the flywheel 1 and rotate in opposite directions to each other. The drums, 3A and 3B, are transmission gears rotated by the control motor M, 4A, 4B are drive gears provided coaxially with the drums 2A, 2B, facing the transmission gears 3A, 3B, and 5 are drive gears 4A, An output gear meshing with 4B is an output shaft to which the output gear 5 is fixed.

A gear portion 11 is formed on the flywheel 1, and gear portions 21 and 21 are formed on the drums 2A and 2B, respectively. The drums 2A and 2B are installed in parallel around the gear 11 of the flywheel 1. In particular, one of the drums 2A has its gear 21 directly meshed with the gear 11 of the flywheel 1 so that the flywheel 1
And the other drum 2B meshes its gear 21 with the gear 11 of the flywheel 1 via an idle gear (not shown) so that it rotates in the same direction as the flywheel 1. I have.

The transmission gears 3A and 3B are rotatably provided on the outer circumferences of the drums 2A and 2B, respectively, and mesh with the gear 7 to which the power of the control motor M is transmitted. In addition,
The control motor M is a reversible variable speed motor belonging to a servo motor such as a stepping motor. The drive gears 4A and 4B are rotatably provided coaxially with the drums 2A and 2B, respectively, and mesh with the output gear 5.

FIG. 2 shows a cross section taken along the line AA in FIG. In FIG. 2, reference numeral 8 denotes a housing of the apparatus,
Two support shafts 9 are fixed inside thereof in parallel with the output shaft 6. A bearing 1 is provided at one end of the support shafts 9 and 9.
Drums 2A and 2B are rotatably provided via a shaft 2 respectively, and drive gears 4A and 4B are rotatably provided via bearings 13 on the other end sides of the support shafts 9 and 9, respectively. Transmission gears 3A, 3B are rotatably provided on the outer periphery of the drums 2A, 2B via bearings 14, and the transmission gears 3A, 3B are meshed with the gear 7 as described above. The gear 7 is fitted on a rotating shaft 16 supported on the upper part of the housing 8 via a bearing 15. The rotating shaft 16 has one end protruding outside the housing 8 and a pulley 17 fitted on one end thereof. I have. The pulley 17 and the control motor M
Pulley 18 fitted to the drive shaft of
9 is linked.

On the other hand, the output shaft 6 passes through the center of the housing 8 and is supported by a bearing 22. The output shaft 6 has both ends protruding outside the housing 8, and the flywheel 1 is rotatably provided at one end via a bearing 23, and the drive gear 4 is provided at the other end connected to an external drive system such as a press device.
The output gear 5 meshing with A and 4B is fixed by a key or the like. The flywheel 1 is supported by a bearing 24 fitted to the housing 8, and the gear 11 is housed inside the housing 8 and meshed with the gear 21 of the drum 2A.

Here, spiral traction coils C and C 'having different winding directions are provided on the outer periphery of the drums 2A and 2B. One ends of the traction coils C and C 'are respectively engaged with end faces of the transmission gears 3A and 3B, and the other ends are respectively engaged with end faces of the drive gears 4A and 4B. The traction coils C and C 'are windings having a rectangular cross section formed by performing a heat treatment such as quenching and tempering.
The rotation direction and the winding direction of B are reversed.

In particular, one of the traction coils C and C 'has a larger number of turns than the other, so that a larger torque can be transmitted. That is, the transmission torque to the output side can be increased in proportion to the number of turns. Therefore, for example, the number of turns of one traction coil C is made larger than the number of turns of the other traction coil C ′,
When the ram of the press device is lowered, the traction coil C is wound around the drum 2A so that a large torque is output to the drive gear 4A.

The traction coils C and C 'are respectively connected to the drive gears 4A and 4B from the transmission gears 3A and 3B.
The cross-sectional shape gradually increases toward the side. This is because, for example, when one traction coil C is wound around the drum 2A to operate the output shaft 6, a larger force acts on the traction coil C on the drive gear 4A side than on the transmission gear 3A side. ,
For this reason, the shape of the traction coils C and C 'is changed so that the stress acting on an arbitrary section becomes constant.

The traction coils C, C '
For example, chucking and rotating a cylindrical carbon steel as a material on an NC lathe and rotating, and feeding a predetermined tool sequentially with increasing or decreasing the feed pitch, thereby cutting a spiral groove in the material. Thereafter, the material can be bored by using a tool such as a boring tool to penetrate the groove, and thereafter, it can be manufactured by performing a heat treatment such as quenching and tempering.

FIG. 3 is an enlarged sectional view showing a drum portion. Although the drawing illustrates the drum 2A, the other drum 2B has the same configuration. The structure of the drum 2A will be described below. The drum 2A includes a cylindrical main body 25 on which the gear 21 is formed, and a body 26 fitted on the outer periphery of the main body 25. An oil reservoir 27 is formed on the outer peripheral surface of the main body 25, and a plurality of oil passages 28 communicating with the oil reservoir 27 are formed in the body 26. The lubricating oil flowing out of the oil reservoir 27 through the oil passage 28 allows the lubrication state between the drum 2A and the traction coil C to be maintained. In particular, a step portion 29 having a reduced diameter is provided at one end of the body portion 26 on the drive gear 4A side.
Is formed so that a part of the holder 30 is fitted to the stepped portion 29. Here, a pin 31 is driven from the step surface 29 a of the step portion 29 toward the inside of the body portion 26, and another pin 32 disposed adjacent to the pin 31 is rotatably held by the holder 30. Like that. The pins 31 and 32 are steel bars formed to a required diameter and a required length, and the strength is increased by heat treatment.

FIG. 4 is a sectional view taken along line BB in FIG.
From this figure, it can be seen that the pins 31 are provided on the outer peripheral portion of the drum 2A and are arranged at regular intervals in the circumferential direction of the drum 2A. The pin 31 is fixed to a mounting portion 33 formed on the outer circumference of the drum 2A. Therefore, it can be said that the mounting portion 33 is also formed on the outer circumference of the drum 2A at regular intervals in the circumferential direction. .

FIG. 5 shows a part of FIG. 4 in an enlarged manner. As shown in this figure, the mounting portion 33 is a substantially circular hole formed in the step surface 29a of the step portion 29, and the pin 31
Are fixed in a press-fit state. In particular, a part of the mounting portion 33 is open in the outer circumferential direction of the drum 2A,
A part of the peripheral surface of the pin 31 is exposed at the open portion. The projecting amount is about 20 μm, and the portion is located between the drum 2A and the traction coil C and is in close contact with the inner peripheral surface of the traction coil C in the axial direction of the pin 31.

Next, FIG. 6 shows a state in which the holder 30 is partially broken. As shown in this figure, the holder 30 comprises a cylindrical portion 35 and a flange portion 36 integrally formed at one end thereof. Among them, the cylindrical portion 35 is formed with slits 37 whose one ends are open at regular intervals in the circumferential direction. Here, the holder 30 has the cylindrical portion 35 fitted to the step portion 29 of the drum 2A, and the flange portion 36 is firmly fixed to the end face of the drive gear 4A with bolts or the like. Deploy pin 32 at 37,
The traction coil C is provided on top of it.

FIG. 7 is a partial sectional view showing a state in which the pin 32 is rotatably held by the holder 30. As shown in the figure, the pin 32 is rotatably held by partition walls 38 on both sides of the slit 37, and in this state, both sides in the direction perpendicular to the axis are the outer peripheral surface of the drum 2A and the inner periphery of the traction coil C. It comes into close contact with the surface. Here, the pin 32 is also 20 μm from the outer surface of the cylindrical portion 35.
The portion protrudes to an extent and comes into close contact with the inner peripheral surface of the traction coil C in a line contact state. The cylindrical portion 35 has a thickness equal to the height of the step portion 29 formed on the drum 2A. Will be prevented from coming off.

Next, the operation of the power transmission device configured as described above will be described. First, as shown in FIG. 2, when the flywheel 1 is rotated in the direction of the arrow, the drums 2A and 2B meshing with the flywheel 1 rotate forward and backward, respectively. In particular, the drum 2A without the idle gear rotates in the opposite direction to the flywheel 1, and the drum 2B with the idle gear rotates in the same direction as the flywheel 1.

Then, the control motor M is driven and the gear 7
When the transmission gears 3A and 3B are rotated in the same direction as one of the drums 2A, the one traction coil C is wound around the drum 2A, and the drive gear 4A is connected to the drum 2A.
A rotates in the same direction as A. Therefore, the output shaft 6 is also rotated through the output gear 5 meshing with the drive gear 4A. On the drive gear 4A side, excessive sticking of the traction coil C to the drum 2A is prevented by the pins 31 and 32, so that seizure does not occur between the pins and the energy loss is reduced. C is pulled in the rotation direction of the drum 2A, and the other pin 32 rotates by receiving the adhesion force of the traction coil C and converts the rotation into the propulsion force of the holder 30, so that the flywheel provided to the drum 2A The first power is efficiently transmitted to the output shaft 6 in the form of a pulse having a small torque fluctuation.

At this time, the other traction coil C 'is pushed at one end by the transmission gear 3B and pulled at the other end by the drive gear 4B rotated by the output gear 5, so that the other traction coil C' Will spin without winding.

When the drive gear 4A attempts to exceed the rotational speed of the transmission gear 3A due to its inertia, the other drive gear 4B rotated via the output gear 5 rotates at a higher speed than the transmission gear 3B. At this time, the traction coil C 'is wound around the drum 2B and acts to brake the drive gear 4A.

Accordingly, the drive gears 4A, 4B instantaneously respond to the speed change gears 3A, 3B rotated by the control motor M, and rotate at the same speed. A definite exercise proportional to the amount of movement is performed. Therefore, the displacement amount and speed of the drive system driven by this power transmission device are used as digital signals to control the motor M.
If the rotation speed of the control motor M is appropriately changed based on the signal, the output shaft 6 responds at a high speed. When the output shaft 6 is reversed, the control motor M may be reversed, and at this time, the traction coils C and C 'perform the reverse operation.

When the output shaft 6 rotates forward, the control motor M
Is stopped, the power transmission by the drive gear 4A to the output gear 5 is cut off, while the other drive gear 4B is rotated by the inertia force of the output gear 5, and one end of the traction coil C 'is pulled by the drive gear 4B. As a result, the traction coil C 'rapidly winds around the rotating drum 2B on the opposite side of the drive gear 4B, so that the output gear 5 and the output shaft 6 stop instantaneously. Incidentally, the output shaft 6 during reverse rotation also stops instantaneously in response to the stop operation of the control motor M.

In short, if the control motor M is driven in the direction of rotation of the flywheel 1, the output shaft 6 will also rotate in the same direction, and if it is driven in the opposite direction, the output shaft 6 will also reverse. When the control motor M is stopped, the output shaft 6 that is rotating forward or reverse is instantaneously stopped.

As described above, a preferred example of the present invention has been described.
In addition to the basic structure of the power transmission device shown in FIGS. 1 and 2, there are four drums, a transmission gear, and a drive gear arranged in parallel, and two drums arranged in series. .

[0035]

As is apparent from the above description, according to the present invention, since the pins are arranged annularly at a required interval between the drum and the traction coil, an excessive amount of the traction coil relative to the drum is provided. Adhesion is prevented, and energy loss during power transmission can be greatly reduced.

In particular, since the pin is fixed to the mounting portion formed on the outer periphery of the drum, the traction coil wound around the drum is pulled by the pin in the same direction. It can be efficiently transmitted to the output side.

Further, since another pin is held by the holder adjacent to the pin, the adhesion of the traction coil to the pin can be smoothly transmitted to the output side through the holder, and the pin can be rotated. Because it is free, wear due to friction with the traction coil is small and durability is good.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing an example of a power transmission device according to the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is an enlarged cross-sectional view of a drum.

FIG. 4 is a sectional view taken along line BB in FIG. 3;

FIG. 5 is a partially enlarged view showing a part of FIG. 4 in an enlarged manner;

FIG. 6 is a perspective view showing a holding tool partially cut away;

FIG. 7 is a partial cross-sectional view showing a state where a pin is held by a holder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flywheel 2A, 2B Drum 3A, 3B Transmission gear 4A, 4B Drive gear 5 Output gear 6 Output shaft 30 Holder 31, 32 Pin 33 Mounting part C, C 'Traction coil M Control motor

Claims (1)

(57) [Claims] 1. A drum which is rotated by transmitting the power of a flywheel, a transmission gear rotatably provided on an outer periphery of the drum and rotated by a control motor, and a drum facing the transmission gear. A drive gear provided coaxially and meshing with an output gear fixed to an output shaft; and a drive gear mounted on the outer periphery of the drum and having one end locked to the transmission gear and the other end locked to the drive gear. And a helical traction coil formed on the outer peripheral surface of the drum, a mounting portion for fixing a pin at a required interval in a circumferential direction of the drum, and the drive gear is adjacent to the pin. Then, a retainer for rotatably holding other pins is fixed, and the pins are located between the drum and the traction coil, and a part of the peripheral surface is in the axial direction. A power transmission device characterized in that it comes into close contact with the inner peripheral surface of a coil.