JPH0749110Y2 - Belt transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a belt rotation transmission device.

[Prior Art] A belt transmission device used for transmitting rotation in a mechanical device winds a belt around a drive-side pulley and a driven-side pulley to rotate the drive-side pulley through the belt. It is transmitted to the pulley.

Therefore, in the belt transmission device, generally, the driving pulley and the driven pulley are fixedly provided in a fixed positional relationship. However, depending on the type of the mechanical device, the belt transmission device is used even when the rotation is transmitted between two members that are close to and away from each other. That is, a pulley is provided on each of two members that can move in the direction of relatively approaching and separating, and the belt is wound between both pulleys.

In this case, the axial distance between the pulleys provided on each member changes according to the change in the distance between the two members.

Therefore, in the belt transmission device provided between the two members that are relatively close to and separated from each other in this way, the maximum distance between the two members, that is, the maximum inter-axis distance can be set on the belt that is wound between the pulleys in advance. Using a belt of a corresponding length, a lever with a tension pulley supported at the tip of one member is swingable, and a spring is connected to the lever, and the lever swings toward the belt by spring force. Then, the tension pulley is brought into contact with the belt to apply tension to hold the belt in a tensioned state.

That is, when the two members are separated from each other and the pulleys are separated from each other, the belt wound around the pulleys is tensioned, and when the two members are close to each other and the pulleys are close to each other, the belt is relaxed. When the distance between the two members changes in this way and the distance between the pulley axes changes, the tension state of the belt changes accordingly. For this reason, the tension lever is pulled by a spring while the tension pulley is in contact with the belt and swings in response to changes in the belt state, and tension is applied to the belt, regardless of the size of the pulley shaft distance. Is intended to be held in a tensioned state with a predetermined tension.

(Problems to be solved by the invention) However, the belt transmission device provided between the two members relatively approaching and separating as described above has the following problems.

If the two members move rapidly when they move apart, the belt will become tense rapidly, and the tension lever will not be able to stably follow this rapid change in the belt and will bounce up onto the belt. May be Then, the tensioned state of the belt is released, and when the belt is rotating, the rotation transmission by the belt becomes unstable, which may support the rotation of the driven pulley, and the belt may come off the pulley. Sometimes.

Also, the tension lever is in an unstable state in which it can swing freely by only receiving a spring force, and it may easily tilt due to external vibration to change its position with respect to the belt. Therefore, the tension applied to the belt by the tension lever is unstable, and the required belt tension may not be maintained. In this case, a sufficient frictional state may not be obtained between the belt and the pulley, which is one of the causes for increasing the loss in transmitting the rotation of the belt from the driving pulley to the driven pulley. Has become.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a belt transmission device capable of stably transmitting rotation between pulleys provided on two members that are relatively displaced.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a belt transmission device of the present invention comprises:
A first pulley provided on one member of the two members displaceable in the direction of relatively approaching and separating, and a second pulley provided on the other member of the two members, Tension supporting a belt wound around the first pulley and the second pulley, and a pulley whose one end is pivotally supported by one member of the two members and whose other end is in rotational contact with the inner surface of the belt. A lever, a first rod having a screw portion pivotally supported by the other member of the two members, and a screw portion pivotally supported by the tension lever and having a reverse thread to the screw of the first rod A second rod and a threaded portion of these first rods and a nut screwed into the threaded portion of the second rod are provided, and the rotation of this nut causes the first rod and the second rod to axially move. And a connecting member having a main body for relatively moving toward and away from each other. [Operation] When the two members are displaced away from each other, the tension lever is pulled by the connecting member and swings the two members according to the separation distance, so that the tension lever may be flipped up by the belt. Stable and keep the belt tensioned.

In addition, the tension lever is restrained by the connecting member.
Since the position is defined according to the distance between the individual members, the belt can be stably tensioned with a predetermined tension and the rotation transmission can be stably performed.

[Embodiment] An embodiment of the present invention shown in the drawings will be described below.

This embodiment is an example in which the belt transmission device of the present invention is incorporated in a part of a rotation transmission system for transmitting the rotation of an electric motor to a spindle for driving a milling cutter in a horizontal milling machine.

FIG. 4 shows a horizontal milling machine provided with the belt transmission device of the present invention.

In the figure, 1 is a base, 2 is a column provided on the base 1, 3
Is a cutter head provided on the upper part of the column 2 so as to be vertically movable and provided with a main shaft 4. The cutter head 3 is vertically moved by an elevating device 5 provided inside the column 2. 6 is an overarm provided on the upper part of the cutter head 3, and 7 is a cutter arbor to which a milling cutter 8 is attached.
Is connected to the main shaft 4 of the cutter head 3 and rotates. 9 is a knee, 10 is a saddle, and 11 is a table. A workpiece is placed on the table 11 and processed by a milling cutter 8.

In the horizontal milling machine having this configuration, after moving the table 11 on which the workpiece is placed during machining from the machining start end to the machining end end, the cutter head 3 is raised and the milling cutter 8 is raised to allow the table 11 to escape. Is returned to the machining start end with the workpiece placed, and the workpiece is removed from the table 11 at that position. Therefore, there is an advantage that the table 11 does not have to be stopped twice in the process of reciprocating once during the processing, and the processing can be performed efficiently.

12 is an electric motor provided on the base 1, 13 is a stepped pulley provided at the bottom of the column 2, 14 is a belt wound around the pulley 15 and the stepped pulley 13 attached to the rotating shaft of the electric motor 12, and this belt 14 transmits the rotation of the electric motor 12 to the stepped pulley 13. Further, the rotation of the stepped pulley 13 is transmitted to the belt transmission device of the present invention provided above it.

The belt transmission device of the present invention will be described with reference to FIGS.

In this embodiment, the two members that are relatively close to and separated from each other are the column 2 and the cutter head 3, and the column 2 is fixed, but the cutter head 3 can move up and down with respect to the column 2. It is provided.

In the figure, 16 is a stepped pulley provided on the column 2 side.
Is rotatably supported by a shaft (not shown) provided horizontally on the vertical wall of the. The shaft supporting the stepped pulley 17 is connected to the main shaft 4. Reference numeral 17 denotes a stepped pulley provided on the cutter head 3 side, and is rotatably supported by a shaft (not shown) horizontally provided on the vertical wall portion of the cutter head 3 just above the pulley 16. A belt 32 is wound around the pulley 17 and the pulley 13 located below the pulley 17. Cutter head 3
By moving up and down with respect to the column 2, the distance between the axis of the stepped pulley 16 provided on the column 2 side and the axis of the stepped pulley 17 provided on the cutter head 3 side changes. Reference numeral 18 is an endless belt wound around the stepped pulley 16 and the stepped pulley 17, and is a stepped pulley when the cutter head 3 is lifted by the maximum distance with respect to the column 2.
It has a length corresponding to the distance between the axis of 16 and the axis of the stepped pulley 17.

Reference numeral 19 denotes a tension lever, which is arranged between the stepped pulley 16 and the stepped pulley 17, that is, in a portion surrounded by the belt 18, in parallel with the vertical wall portions of the column 2 and the cutter head 3. One end (lower end) of the tension lever 19 is rotatably supported by a shaft 20 horizontally provided on the wall of the column 2 via a bearing 21, and the other end (upper end) is attached with a shaft 22.
A tension pulley 24 is rotatably supported on the shaft 22 via a bearing 23. The tension lever 19 has a length that can apply a required tension to the belt 18 when the axial distance between the stepped pulley 16 and the stepped pulley 17 is maximum and minimum. The tension pulley 24 has a width corresponding to the width of the belt 18. The tension lever 19 can swing vertically about the shaft 22 and is always inclined toward one side portion of the belt 18, so that the tension pulley 24 comes into rotational contact with the inner peripheral surface. There is.

Reference numeral 25 denotes a connecting member, which is composed of a cylindrical body 26 that is a main body, a rod 27 that is a first rod, and a rod 28 that is a second rod.
The cylinder 26 has nuts 29, 29 attached to both ends,
These nuts 29, 29 are reverse threads to each other. Stick 2
Reference numerals 7 and 28 have threaded portions, and are respectively screwed into nuts 29 and 29 at both ends of the tubular body 26. And sticks 27, 28
When the cylinder 28 is rotated by pressing the rotation of the nuts 29, 29, the nuts 29, 29 are also rotated so that the rods 27, 28 move in and out of the cylinder 26. Connecting member
25 is arranged vertically on the outside of the tension lever 19, one rod 27 is rotatably connected to a bolt 30 horizontally provided on the tension lever 19, and the upper end is the cutter head 3
Is rotatably connected to a bolt 31 that is horizontally provided at the center of the lower end of the wall portion. In this way, the connecting member 25 connects the tension lever 19 and the cutter head 3. Therefore, the connecting member 25 defines the position of the tension lever 19 in accordance with the position of the cutter head 3, and the vertical movement of the cutter head 3 forces the tension lever 19 to pivot about the shaft 20 in the vertical direction. Let

This connecting member 25 is a nut that rotates the cylindrical body 28 that is the main body.
By simply rotating 29, the rods 27 and 28 are moved in the axial direction to move in and out to adjust the overall length of the connecting member, and the tension lever 19 is tilted to tilt the belt 18.
Can be adjusted to the required value regardless of the size of the gap between the column 3 and the cutter head 3.
Moreover, by combining the threaded portion of each rod and the nut, the movement amount of the rods 27 and 28 is made fine according to the rotation amount of the nut, so that the length of the connecting member 25 is finely changed and the tension of the belt 18 is increased. Can also be finely adjusted.

Further, one rod 27 of the connecting member 25 is directly connected to the tension lever 19 via a bolt 30, and the other rod 28 is directly connected to the cutter head 3 by a bolt 31. Therefore, since the connecting member 25 directly connects the tension lever 19 and the cutter head 3, the tension lever 19 is forcibly rotated to surely stretch the belt 18 with the required tension. When the external force is applied to the tension lever 19 for some reason, the external force causes the tension lever 19 to vibrate,
The tension lever 19 does not jump away from the connecting member 25. If the tension lever 19 vibrates or the tension lever 19 jumps away from the connecting member 25 due to an external force, the belt 18 vibrates and adversely affects the rotation transmission between the pulleys.

Further, one rod 27 of the connecting member 25 is pivotally supported by the tension lever 19 via a bolt 30, and the other rod 28 is pivotally supported by the cutter head 3 by a bolt 31. Therefore, the tension lever 19 is adjusted by adjusting the length of the connecting member 25.
By making it possible to rotate, the connecting member 25 and the tension lever 19 can be directly connected.

As a result, the connecting member 25 stably connects the tension levers 19 and applies a predetermined tension to the belt 18, which contributes to obtaining a belt transmission device having excellent reliability.

The operation of the belt transmission thus configured will be described.

The entire length of the connecting member 25 is adjusted by adjusting the tension so that the belt 18 can be maintained in a tensioned state with a required tension in advance. That is, the tension of the belt is set according to the conditions such as the length of the belt, the material, and the rotation transmission force of the belt. In order to maintain the tension of the belt 18 with a predetermined tension required regardless of the distance between the column 2 and the cutter head 3, the tension lever is adjusted according to the distance between the column 2 and the cutter head 3. Tilt 19 and apply an appropriate force to the belt 18 with the tension pulley 24 provided on the tension lever 19. Therefore, the length of the connecting member 25 is adjusted so that the tension lever 19 is inclined at an appropriate angle according to the size of the distance between the column 2 and the cutter head 3. Connecting member 25
Adjusts the length by rotating the tubular body 26 to move the rods 27 and 28 forward and backward.

As a result, the tension lever 19 is held by the connecting member 25 and is defined at an appropriate position according to the size of the gap between the column 2 and the cutter head 3. Tension pulley 19 is a belt
Apply appropriate force to 18. The belt 18 is wound around the stepped pulley 16, the stepped pulley 17 and the tension pulley 24, and is stretched with a predetermined tension according to the size of the gap between the column 2 and the cutter head 3.

When the electric motor 12 provided on the base 1 of the horizontal milling machine is driven, its rotation is transmitted through the pulley 15, belt 14, stepped pulley 13 and belt 32, and the stepped pulley 16 of the belt transmission device of the present invention provided on the column 2 Be transmitted to. The belt 18 is rotated by the rotation of the stepped pulley 16, the stepped pulley 17 provided on the cutter head 3 is rotated, the spindle 4 provided on the cutter head 3 is further rotated, and the cutter arbor 7 provided with the milling cutter 8 is rotated. It In this case, since the belt 18 is stably stretched with a predetermined tension, the rotation is stably transmitted. Further, the tension lever 19 does not move due to external vibration, and the position with respect to the belt 18 does not change. Therefore, a sufficient friction state is obtained between the belt 18 and the pulleys 15 and 18, and the belt can transmit the rotation from the stepped pulley 16 to the stepped pulley 17 without a large loss.

Therefore, even when the work part mounted on the table 11 gives a large resistance to the milling cutter 8, the belt 18 can reliably transmit the rotation to rotate the milling cutter 8.

Then, when the cutter head 3 of the horizontal milling machine is raised, for example, as necessary, the distance between the cutter head 3 and the column 2 is increased, and the axial center of the stepped pulley 16 and the stepped pulley 17 are increased.
The distance from the axis of the is increased. As the cutter head 3 rises, the connecting member 25 moves upward, and at the same time, the tension lever 19 pivots upward about the shaft 20. As a result, the tension lever 19 is held by the connecting member 25 and is regulated to have an appropriate tilt according to the size of the gap between the column 2 and the cutter head 3. Tension pulley 24 is a belt
Apply appropriate force to 18. Even when the cutter head 3 is rapidly raised, the tension lever 19 is rotated by the connecting member 25, so that the tension lever 19 is stably rotated and is not pushed by the belt 18 to jump up, and stable rotation transmission can be performed. Further, it is possible to prevent the belt from coming off the pulley.

When the cutter head 3 of the horizontal milling machine is lowered as necessary, the connecting member 25 is also lowered and the tension lever 19 is moved.
Rotate downward. This allows the tension lever 19
Is held by the connecting member 25 and is regulated to an appropriate tilting according to the size of the gap between the column 2 and the cutter head 3. The tension pulley 24 applies an appropriate force to the relaxed belt 18.

The present invention is not limited to the rotation transmission system of the horizontal milling machine and can be applied to various rotation transmission systems.

[Advantage of Invention] As described above, according to the belt transmission device of the present invention,
When the two members are displaced away from each other, the tension lever is pulled by the connecting member and the two members are tilted according to the separation distance. Therefore, the tension lever is not flipped up by the belt and the belt is stably moved. The tension lever can be held in a tensioned state, and the tension lever is constrained by the connecting member and regulated to an inclined position according to the distance between the two members. Therefore, the tensioned state of the belt can be stably secured. Rotational transmission can be stably performed.

Therefore, according to the present invention, it is possible to obtain a belt transmission device that can stably transmit rotation between pulleys provided on two members that are relatively displaced.

In addition, the connecting member moves the first and second rods movably in the axial direction by a simple operation of simply rotating the main body and rotating the nut to move the first rod and the second rod in and out to move the connecting member to the entire length. And the tension lever can be tilted to adjust the belt tension to the required value regardless of the size of the gap between the first member and the second member. Moreover, by combining the threaded portion of each rod and the nut, the movement amount of the rod is made fine according to the rotation amount of the nut, so that the length of the connecting member is finely changed and the tension of the belt is finely adjusted. be able to.

Further, the first rod of the connecting member is directly connected to the tension lever by one of the rods, and the second rod is directly connected to the cutter head by the bolt. For this reason, since the connecting member directly connects the tension lever and the cutter head, the tension lever can be forcibly rotated and the belt can be surely tensioned with the required tension. At the same time, when an external force is applied to the tension lever for some reason, the tension lever does not vibrate and the tension lever does not jump away from the connecting member. If the tension lever vibrates or the tension lever jumps apart from the connecting member due to an external force, the belt vibrates and adversely affects the rotation transmission between the pulleys.

Furthermore, since one rod of the connecting member is pivotally supported by the tension lever via the bolt and the other rod is pivotally supported by the cutter head by the bolt, the connecting member and the tension lever are directly connected to each other. By adjusting the length of the connecting member, the tension lever can be rotated in a wide angle range, and as a result, the tension of the belt can be adjusted in a wide range.

As a result, the connecting member stably connects the tension levers and applies a predetermined tension to the belt, thereby contributing to obtaining a belt transmission device having excellent reliability.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a front view showing a belt transmission, FIG. 2 is a side view showing the same, FIG. 3 is a side view showing a connecting member, and FIG. It is a figure which shows the provided horizontal milling machine. 1 ... Base, 2 ... Column, 3 ... Cutter head, 1
6,18 …… Step pulley, 20 belt, 19 …… Tension lever, 22 …… Tension pulley, 25 …… Coupling member.

Claims (1)

[Scope of utility model registration request] 1. A movable member 2 which can be displaced in a direction of relatively approaching and separating.
A first pulley provided on one of the two members, a second pulley provided on the other of the two members, and a first pulley and a second pulley. A wound belt, a tension lever that has one end pivotally supported by one of the two members, and a tension lever that supports a pulley that makes rotational contact with the inner surface of the belt at the other end, and the other of the two members. A first rod having a threaded portion pivotally supported by a member, a second rod pivotally supported by the tension lever and having a threaded portion reverse to the thread of the first rod, and the screws of these first rods And a connecting member having a main body for moving the first rod and the second rod toward and away from each other in the axial direction by rotation of the nut, the nut being screwed to the threaded portion of the second rod. And a belt transmission device.