JP2021124198A - Wire constant tension device - Google Patents

Abstract

To provide a wire constant tension device having a simple structure which does not need manual periodical inspection and maintenance.SOLUTION: A wire constant tension device has a female screw support member, a drive screw screwed to the female screw support member, a driven wheel unit for rotatably supporting a wire-winding driven wheel, an eccentric member which rotates together with the driven wheel, a pivot member fit to the drive screw via a one-way clutch, an oscillation member partially fixed to the pivot member, and slidably contacting with the eccentric member at one end part, and a spring bridged between a part of the oscillation member and a part of the driven wheel unit. The spring has a spring constant for rotating the drive screw in a direction in which the tension of the wire is increased while withstanding the tension of the wire when the tension of the wire is dropped to a prescribed value or lower.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wire constant tension device.

A force that hangs a wire between at least two pulleys, rotates at least one pulley (drive pulley) while maintaining tension, and transmits that force to one fixed to the wire or another pulley (driven pulley). Transmission technology is widely applied in the field of industrial technology.

In this force transfer technique, it is important to maintain the tension of the wire. This is because if the tension of the wire is not maintained, the force is not sufficiently transmitted or it causes problems such as noise and vibration.

In order to explain this, the wire feeding device will be generally described below, but the present invention is not limited to the category of the wire feeding device, and the present invention relates to a constant tension device of a force transmission technique using a pulley widely.

In recent years, the technical demand for quickly and accurately transporting an object to a predetermined position has been increasing year by year.

Therefore, various transfer devices have been devised. Types of conveyors include, for example, belt conveyor drives, ball screw drives, timing belts, and wire feeders.

Belt conveyor drive is a mechanism or device that rotates a ring-shaped belt to convey an object, but it is highly versatile. However, the positioning accuracy of the transported object is not good, and the transport speed is also slow.

A timing belt is a drive mechanism in which a belt with tooth-shaped irregularities and a tooth mold provided on a pulley are meshed with each other. Although it has a certain degree of high speed, it may cause a problem of tooth skipping at high speeds. There is.

The ball screw drive rotates the ball screw to convert the screwed female screw into a linear movement, but the transfer accuracy is good. However, the transport distance is limited to several meters or less, and the transport speed is also slow.

The wire feeding device is a device that conveys an object by driving a wire laid between at least two pulleys, and has both high speed and accuracy of conveying. For this reason, demands are increasing in recent years.

However, the wires used in wire feeders have the problem of stretching.

The wire used in the wire feeding device is formed by further bundling 6 to 7 strands of thin metal wires. Since the wire is twisted and manufactured in this way, the wire has a gap between the metal wires immediately after the manufacture. Therefore, when tension is applied during use, the metal wires come close to each other and the length increases accordingly. The elongation of this wire does not converge in a short time, but gradually occurs for a relatively long period of time with use. Also, the elongation is not linear.

In a wire feeding device, when a wire is stretched, the tension is lowered and the wire is loosened, which may cause vibration or abnormal noise. Not only is vibration and abnormal noise unfavorable in use, but there is also the problem that the positioning accuracy of the transported object is lowered by the vibration, and the portion where the wire is repeatedly bent due to the vibration becomes metal fatigue, and the life of the wire is shortened.

As a countermeasure, it is necessary to maintain the tension of the wire by increasing the distance around which the wire is hung as the wire is stretched.

In the conventional wire feeding device, in order to increase the distance around which the wire is hung according to the elongation of the wire, for example, one of the driven pulleys is moved by a screw, thereby increasing the distance around which the wire is hung. It was broken. However, since this work must be performed manually on a regular basis, the burden of maintenance work is heavy.

On the other hand, a wire constant tension device has been proposed in which the tension of the wire is automatically increased as the wire is stretched to maintain the initial wire tension.

Japanese Unexamined Patent Publication No. 2012-002297 International Publication No. 2013/137139

Both of the wire constant tension devices according to Patent Documents 1 and 2 can automatically adjust the wire tension without requiring manual periodic tension adjustment. The mechanism for automatically adjusting the wire tension according to Patent Documents 1 and 2 will be described below by taking Patent Document 2 as an example.

FIG. 6 shows a wire constant tension device according to Patent Document 2 (“feed error correction device for feed device” in Patent Document 2).

The wire constant tension device according to Patent Document 2 has a wire 161B and a driven wheel 172. The wire 161B is tensioned around between a driving wheel and a driven wheel 172 (not shown). The driven wheel 172 is rotatably supported by a driven wheel axle 173. Above the driven wheel axle 173, the first transmission shaft 182A is rotatably supported horizontally. The driven wheel axle 173 and the first transmission shaft 182A are provided so as to be able to transmit power to each other via the first transmission gear 183a and the second transmission gear 183b made of bevel gears.

An eccentric member 218 is fitted to the other end of the first transmission shaft 182A. The rotation of the eccentric member 218 is converted into the axial movement of the telescopic arm 211 that engages with it, and the axial movement of the telescopic arm 211 is converted into the swing of the swing arm 231.

The swing arm 231 is configured to rotate integrally with the holding member 233. The holding member 233 has a one-way clutch 234 inside the holding member 233, and has a female screw 193 further inside the holding member 234 via the one-way clutch 234. The female screw 193 is screwed with one end of a horizontal and rotatably supported male screw 192, and is configured to move the male screw 192 in the axial direction by the rotation of the female screw 193. The other end of the male screw 192 is connected to a support member 174 that supports the driven wheel set 173. It is assumed that the direction of the screw is configured so that the male screw 192 is moved to the left in FIG. 6 when the swing arm 231 is swung counterclockwise.

According to the above configuration, in the wire constant tension device according to Patent Document 2, when the driven wheel 172 is rotated by the drive wheel, the first transmission shaft 182A rotates and the eccentric member 218 at the end of the first transmission shaft 182A rotates. .. When the eccentric member 218 rotates, the telescopic arm 211 moves back and forth in the axial direction. When the telescopic arm 211 moves downward, the swing arm 231 swings counterclockwise, causing the female screw 193 to rotate counterclockwise (the movable direction of the one-way clutch 234). When the female screw 193 rotates, the male screw 192 moves in the axial direction (leftward in FIG. 6), and accordingly, the driven wheel axle 173 and the driven wheel 172 move to the left in FIG. 6, and the tension of the wire 161B increases.

When the tension of the wire 161B is increased, the angle of the swing arm 231 is maintained by the reverse rotation limitation of the one-way clutch 234, and the state is maintained as long as the tension of the wire 161B is maintained. However, when the tension of the wire 161B decreases again, the swing arm 231 swings and returns to its original position, and as described above, the swing arm 231 swings counterclockwise again due to the rotation of the eccentric member 218. The female screw 193 is retightened.

As described above, the wire constant tension device according to Patent Document 2 can completely eliminate periodic manual inspections and maintenance, and provides an excellent device as a function.

However, since the conventional wire constant tension device has a large number of parts, there is a limit in reducing the manufacturing cost. In addition, the structure is complicated, and there is a limit to compactness.

Therefore, an object of the present invention is to provide a wire constant tension device having a simple structure that does not require periodic manual inspection or maintenance in the field of a force transmission mechanism using a wire and a pulley in view of the above-mentioned conventional problems. To do.

The wire constant tension device of the present invention is, for example,
Female screw support member and
The drive screw screwed to the female screw support member and
A driven wheel unit that rotatably supports a driven wheel around which a wire is hung, engages with the drive screw, and can move in parallel with the central axis of the drive screw.
An eccentric member that rotates with the driving wheel,
A fulcrum member that fits into the drive screw via a one-way clutch,
A swing member whose part is fixed to the fulcrum member and one end of which is slidably in contact with the eccentric member.
It has a spring that is hung between a part of the swing member and a part of the driven wheel unit.
The spring has a spring constant that overcomes the tension of the wire and rotates the drive screw in a direction in which the tension of the wire increases when the tension of the wire drops below a predetermined value.

The driven wheel unit supports the driven wheel so that the driven wheel axis of the driven wheel is substantially orthogonal to the driving screw and has approximately the same height.
The eccentric member is provided at one end of the driven wheel axle and is provided.
The swing member is configured to swing like a seesaw with the fulcrum member as a fulcrum.
The spring may be hung between an end opposite the end that is slidably in contact with the eccentric member and a portion of the driven wheel unit.

The driven wheel unit supports the driven wheel so that the driven wheel axis of the driven wheel is substantially orthogonal to the driving screw and has approximately the same height.
The eccentric member is provided at one end of the driven wheel axle and is provided.
In the swing member, the end opposite to the end that is slidably in contact with the eccentric member is fixedly connected to the fulcrum member.
The spring may be hung between an end that is in sliding contact with the eccentric member and an end that is fixedly connected to the fulcrum member.

The driven wheel unit supports the driven wheel so that the driven wheel axis of the driven wheel is substantially orthogonal to the driving screw and has approximately the same height.
The eccentric member is provided at one end of the driven wheel axle and is provided.
The swing member is connected to a first swing member that swings like a seesaw with the fulcrum member as a fulcrum, and a fulcrum provided in a part of the driven wheel unit, which is connected to the first swing member by a pivot joint. Including a second swinging member that swings like a seesaw with the member as a fulcrum,
The spring is hung between the end of the first swing member or the second swing member and a part of the driven wheel unit on the opposite side of the end that is in sliding contact with the eccentric member. You may do so.

The female screw support member may be arranged on the same side as the side on which the wire is hung with respect to the driven wheel.

The female screw support member may be arranged on the side opposite to the side on which the wire is hung with respect to the driven wheel.

The swinging member may have a roller at an end that is slidably in contact with the eccentric member.

The wire feeding device according to the present invention is, for example,
The wire constant tension device may be included, and a wire may be hung and routed between a driven wheel of the wire constant tension device and at least one pulley including a drive wheel.

According to the present invention, in a force transmission mechanism using a wire and a pulley, the constant wire tension can be automatically maintained by a simple structure without requiring periodic manual inspection and maintenance. You can get the device.

Plan view (FIG. 1 (a)), side view (FIG. 1 (b)), and side view (FIG. 1 (c)) of the wire constant tension device according to the first embodiment in the direction of arrow P in FIG. 1 (b). , FIG. 1 (b) is a side view in the direction of the Q arrow (FIG. 1 (d)), and FIG. 1 (b) is a side view of FIG. 1 (b) in the direction of the R arrow (FIG. 1 (e)). A plan view (FIG. 2 (a)), a side view (FIG. 2 (b)), and a side view (FIG. 2 (c)) of the wire constant tension device according to the second embodiment in the direction of the arrow U. , FIG. 2b) is a side view (FIG. 2 (d)) in the direction of arrow V. Plan view (FIG. 3 (a)), side view (FIG. 3 (b)), and side view (FIG. 3 (c)) of the wire constant tension device according to the third embodiment in the direction of arrow S in FIG. 3 (b). , FIG. 3 (b) is a side view (FIG. 3 (d)) in the direction of the arrow T. It is a side view of the wire constant tension device according to 4th Embodiment. It is a perspective view of the wire feeding device to which the wire constant tension device according to 1st Embodiment is applied. Plan view (FIG. 6 (a)), side view (FIG. 6 (b)), side view (FIG. 6 (c)) of the conventional wire constant tension device, side view (FIG. 6 (c)) seen from the direction opposite to the wire winding direction, wire. It is a side view (FIG. 6 (d)) seen from the hanging direction of.

An embodiment will be described below.

FIG. 1 shows a wire constant tension device 100 according to the first embodiment. 1 (a) is a plan view of the wire constant tension device 100, FIG. 1 (b) is a side view of the wire constant tension device 100, and FIG. 1 (c) is a wire constant tension in the P arrow view direction of FIG. 1 (b). A side view of the device 100, FIG. 1 (d) is a side view of the constant tension device 100 in the Q arrow direction of FIG. 1 (b), and FIG. 1 (e) is a wire in the R arrow direction of FIG. 1 (b). A side view of the constant tension device 100 is shown.

The wire constant tension device 100 is configured on the base plate 101. A nut support member 102 having a pair of facing side walls as shown in FIG. 1 (e) is fixed to the base plate 101. Further, a guide rail 103 extending parallel to the center of the side wall facing the nut support member 102 is fixed to the base plate 101. A driven wheel 104 is mounted on the guide rail 103, and a driven wheel unit 105 that can move along the guide rail 103 as a whole is mounted.

A female screw member 106 is supported between both side walls of the nut support member 102. The female screw member 106 is formed with recesses 107 on both sides facing each other. The tip of the fixing screw 108 that penetrates the side wall of the nut support member 102 penetrates into the recess 107, and the female screw member 106 is firmly fixed to the nut support member 102. The female screw member 106 may be fixed to such an extent that it can rotate about the penetrating direction of the fixing screw 108 as a rotation axis.

A drive screw 109 is screwed into the screw hole inside the female screw member 106. That is, the drive screw 109 is substantially parallel to the guide rail 103. The drive screw 109 can be moved in the axial direction by rotating about the central axis in the length direction.

The driven wheel unit 105 includes a shoe 110 that slides on the guide rail 103 while being fitted with the guide rail 103, a bottom wall 111 fixed on the shoe 110, and a guide rail 103 erected on the bottom wall 111. It has a pair of side walls 112 that are substantially parallel to each other and a front wall 113 that faces the nut support member 102.

A drive screw bearing 114 is fixed to the front wall 113 of the driven wheel unit 105, and rotatably supports the end portion of the drive screw 109 described above. The drive screw 109 is supported by the female screw member 106 and the drive screw bearing 114 and can stably rotate around the central axis.

A driven wheel bearing 115 is fixed at a position facing the side wall 112 of the driven wheel unit 105. The driven wheel bearing 115 rotatably supports the driven wheel axle 116. That is, the driven wheel axle 116 is supported horizontally and rotatably perpendicular to the guide rail 103 and the drive screw 109. Preferably, the driven wheel set 116 is at the same height as the drive screw 109.

A driven wheel 104 is fixed on the driven wheel axle 116. A wire 117 is hung around the driven wheel 104. The wire 117 is hung with tension between it and a drive wheel (not shown).

One end of the driven wheel set 116 (the lower end in FIG. 1A) protrudes from the side wall 112, and an eccentric member 118 is fixed to the tip thereof. The eccentric member 118 has an outer peripheral surface having different distances in the radial direction from the center of the driven wheel set 116. That is, the outer peripheral surface of the eccentric member 118 is a cam. A roller 120, which will be described later, is in contact with the eccentric member 118.

On the outside of one side wall 112 and the front wall 113, a substantially L-shaped swinging member 119 extends in a plan view. The swing member 119 is integrally fixed to the fulcrum member 122 fitted around the drive screw 109 with the one-way clutch 121 interposed therebetween. The swing member 119 is supported by the fulcrum member 122, and can swing around the fulcrum member 122 in a seesaw shape.

One side of the fulcrum member 122 of the swing member 119 extends to the end portion of the front wall 113 (upper side of FIG. 1A), and the first end portion of the tip thereof and the front wall 113 or the bottom wall 111 or the side wall 112. A spring 124 is hung between the bracket 123 extending from a part of the bracket 123. The spring 124 is hung in a tension state, and the tensile force is adjusted in a balanced relationship with the tension of the wire 117 as will be described later.

The other side of the fulcrum member 122 of the swing member 119 extends to the end of the front wall 113 (lower side of FIG. 1A) and further extends along the side wall 112 to the lower side of the eccentric member 118. The roller 120 described above is rotatably supported at the second end of the swing member 119. The second end of the rocking member 119 having the roller 120 is usually urged upward as a reaction to the tension of the spring 124. Therefore, the roller 120 is urged so as to abut on the outer peripheral surface of the eccentric member 118.

The end of the drive screw 109 on the side supported by the drive screw bearing 114 has a stepped portion 125 and is slightly smaller in diameter. The step portion 125 is engaged with a part of the one-way clutch 121 or the fulcrum member 122. Therefore, the drive screw 109 can push the driven wheel unit 105 against the tension of the wire 117 by the step portion 125.

Based on the above structure, the operation of the wire constant tension device 100 will be described below.

The operation when the tension of the wire 117 is increased will be described below.

In FIG. 1B, when the wire 117 on the upper side of the driven wheel 104 is sent in the F direction, for example, the driven wheel 104 rotates, the driven wheel axle 116 rotates accordingly, and the eccentric member 118 fixed to the driven wheel axle 116 rotates. Rotate.

When the eccentric member 118 rotates, the roller 120 is pushed down by the outer peripheral surface portion having a long distance from the center. When the roller 120 is lowered, the end portion of the swing member 119 on which the spring 124 is applied rises against the tensile force of the spring 124 with the fulcrum member 122 as the fulcrum.

When the rotation of the eccentric member 118 progresses and the outer peripheral surface portion has a short distance from the center, the force for pushing down the roller 120 disappears, and the end portion of the swing member 119 on which the spring 124 is applied is pulled downward by the spring 124.

The tensile force of the spring 124 is set large enough to maintain the proper tension of the wire 117. Therefore, when the wire 117 is loose, the end portion of the swing member 119 on which the spring 124 is applied overcomes the wire tension and is pulled downward. As a result, the swing member 119 rotates about the fulcrum member 122, and torque is transmitted to the drive screw 109 via the one-way clutch 121 to rotate the drive screw 109. It should be noted that "exceeding the wire tension" directly means that it is larger than the rotational torque between the drive screw 109 and the female screw member 106 due to the wire tension, but here, including the energy loss, "to the wire tension". "Win".

When the drive screw 109 rotates, the female screw member 106 and the screw move the drive screw 109 in the direction of increasing the tension of the wire 117 (to the left in FIG. 1B). Since the step portion 125 of the tip portion of the drive screw 109 is engaged with the one-way clutch 121 or a part of the fulcrum member 122, the entire driven wheel unit 105 is pushed, and the driven wheel unit 105 is shown along the guide rail 103. 1 (b) Move to the left. As a result, the distance between the pulleys increases and the tension of the wire 117 increases.

Next, the rotation of the driven wheel 104 proceeds, the roller 120 is pushed down again, and the above operation is repeated. When the operation of increasing the tension of the wire 117 is repeated, the stress in the axial direction of the drive screw 109 becomes high, and finally the end portion of the swing member 119 cannot be pulled down by the tensile force of the spring 124. In this state, the spring 124 extends, the roller 120 stops at the farthest point from the eccentric member 118, and the swing member 119 stops swinging.

However, when the wire 117 is stretched by use, the wire tension is reduced, and the axial stress of the drive screw 109 is reduced accordingly, and as a result, the tensile force of the spring 124 again pulls the end of the swing member 119. It can be lowered and retightened.

As described above, according to the present embodiment, when the wire tension decreases, retightening is automatically performed so as to increase the wire tension. As described above, according to the present embodiment, it is possible to provide a wire constant tension device having a simpler mechanism than the prior art and which does not require periodic manual inspection and maintenance.

In the embodiment of the present embodiment, assuming that the eccentricity e of the eccentric member 118 is e = 3 mm, the rotation angle θ of the fulcrum member 122 of the rocking member 119 is θ = 5 °. The amount of movement of the drive screw 109 in the axial direction depends on the lead angle of the screw, but when the rotation angle θ = 5 °, the amount of movement is small. However, as described above, while the tension of the wire 117 is lower than the set value, the retightening of the drive screw 109 is repeated, so that the tension of the wire 117 finally reaches the set value without any problem.

The greater the tensile force of the spring 124, the greater the tension of the wire 117. Therefore, the tensile force of the spring 124 is selected to have an appropriate spring constant so as to have a preferable tension of the wire 117.

The base plate 101 described above can be omitted if there is an arbitrary fixed pedestal. Therefore, the nut support member 102 may be any known female screw support member as long as it can fix the female screw member 106.

Further, the driven wheel unit 105 is not limited to a structure such as a bottom wall 111 or a side wall 112, and may have an arbitrary structure as long as it can rotatably support the driven wheel 104 and can move as a whole. However, in the driven wheel 104, it is preferable that the driven wheel axle 116 is substantially perpendicular to the drive screw 109 and has substantially the same height.

Therefore, the swing member 119 is not limited to the one having an L-shape in a plan view as in the first embodiment, and can be inclined like a seesaw by the fulcrum member 122 fitted to the drive screw 109, and the second end portion. Is directly or indirectly moved up and down by an eccentric member 118 fitted to the driven wheel axle 116 of the driven wheel 104, and the first end is pulled by a spring 124 hung between a part of the driven wheel unit 105. Anything that can be done is sufficient. Therefore, the roller 120 can be a contact portion having a known arbitrary structure as long as it is smoothly driven by the eccentric member 118. Further, if the end portion of the swing member 119 can be slidably contacted with the eccentric member 118, the roller 120 can be omitted.

FIG. 2 shows the wire constant tension device 126 of the second embodiment. Specifically, FIG. 2A is a plan view of the wire constant tension device 126, FIG. 2B is a side view of the wire constant tension device 126, and FIG. 2C is a U arrow view of FIG. 2B. A side view of the wire constant tension device 126 in the direction, FIG. 2 (d) shows a side view of the wire constant tension device 126 in the V arrow-viewing direction of FIG. 2 (b).

In the following description, the same parts as those in the first embodiment will be described with the same reference numerals. In addition, duplicate explanations may be summarized or omitted as appropriate.

The wire constant tension device 126 of the second embodiment is different from the wire constant tension device 100 of the first embodiment in the arrangement of the swing member 127 in a plan view. Specifically, the swing member 127 of the wire constant tension device 126 of the second embodiment is arranged symmetrically with respect to the drive screw 109 in a plan view with respect to the swing member 119 of the first embodiment.

More specifically, the rocking member 127 of the present embodiment has a substantially L-shaped shape in a plan view, and is composed of two straight portions orthogonal to each other. One straight portion extends substantially parallel to the upper side wall 112 in FIG. 2A of the driven wheel unit 105, and the other straight portion extends substantially parallel to its front wall 113. The two straight portions are bent at substantially right angles near the intersection of the side wall 112 and the front wall 113 to form a corner portion.

One end (first end) of the straight portion of the swing member 127 substantially parallel to the front wall 113 is fixed to the fulcrum member 122. The fulcrum member 122 is fitted around the drive screw 109 via the one-way clutch 121. The end of the swing member 127 and the fulcrum member 122 are fixed to each other so as to rotate integrally, but the fulcrum member 122 rotates only in one direction with respect to the drive screw 109 due to the action of the one-way clutch 121. However, it is rotatable with respect to the drive screw 109 in the other direction.

Here, the drive screw 109 is cut into a right-hand thread, and when the fulcrum member 122 rotates clockwise as seen in FIG. 2D, the drive screw 109 rotates together with the fulcrum member 122, and as a result, the drive screw 109 is driven. The screw 109 is pushed as a reaction of the female screw member 106 and moves to the left in FIGS. 2 (a) and 2 (b). In addition, "the fulcrum member 122 rotates clockwise as seen in FIG. 2 (d)" means that the swing member 127 connected to the fulcrum member 122 is seen in FIG. 2 (d) with the fulcrum member 122 as the center. It means that it swings clockwise.

On the other hand, the other end (second end) of the straight portion of the swing member 127 substantially parallel to the side wall 112 has a roller 120. The roller 120 is rotatably attached to the tip of the swing member 127. The roller 120 comes into contact with the outer peripheral surface of the eccentric member 118 and can move up and down according to the rotation of the eccentric member 118. However, unlike the first embodiment, in the present embodiment, the roller 120 is in contact with the eccentric member 118 from above. As is clear, the height of the straight portion parallel to the side wall 112 of the rocking member 127 is arranged at the height of the roller 120.

A spring 124 is hung between a corner portion of the swing member 127 that bends at a right angle or a portion in the vicinity thereof and a bracket 123 extending from a part of the front wall 113 or the bottom wall 111 or the side wall 112. .. The spring 124 is hung in a tensioned state, and the tensile force is adjusted in a balanced relationship with the tension of the wire 117 as described later.

The second end of the rocking member 127 having the rollers 120 is usually urged downward as a pulling action of the spring 124. Therefore, the roller 120 is urged so as to abut on the outer peripheral surface of the eccentric member 118, and moves up and down along the outer peripheral surface of the eccentric member 118 as it rotates.

In this second embodiment, the drive screw 109 is rotatably supported by a female screw member 106, a drive screw bearing 114, and a second drive screw bearing 128. The additional second drive screw bearing 128 is supported by a second drive screw bearing support member 129 extending from the front wall 113. Specifically, the second drive screw bearing support member 129 extends horizontally from a part of the front wall 113 below the drive screw bearing 114, and vertically extends beyond the width of the one-way clutch 121 and the fulcrum member 122. It stands up and supports the second drive screw bearing 128 coaxially with the drive screw 109.

Since the drive screw 109 is supported by the female screw member 106, the drive screw bearing 114, and the second drive screw bearing 128, the drive screw 109 is stably centered without causing minute waviness. It can rotate around an axis. In particular, the drive screw bearing 114 and the second drive screw bearing 128 support the drive screw 109 on both sides of the fulcrum member 122 to which the rotational torque is applied in the width direction, so that the drive screw 109 can be smoothly applied even when a large rotational torque is applied. Can rotate.

In the second embodiment, the operation when the tension of the wire 117 is increased is as follows.

In FIG. 2B, when the wire 117 is fed in the F direction, for example, the driven wheel 104 rotates, the driven wheel axle 116 rotates accordingly, and the eccentric member 118 fixed to the driven wheel axle 116 rotates.

When the eccentric member 118 rotates, the roller 120 is pushed up by the outer peripheral surface portion having a long distance from the center thereof, the corner portion of the swing member 127 moves upward, and the spring 124 is stretched against the tensile force.

When the eccentric member 118 further rotates and becomes an outer peripheral surface portion having a short distance from the center thereof, the force for pushing up the roller 120 disappears, and the swing member 127 is pulled downward by the spring 124.

The tensile force of the spring 124 is set large enough to maintain the proper tension of the wire 117. Therefore, when the wire 117 is loose, the spring 124 pulls the corner portion of the swing member 127 downward, overcoming the wire tension. As a result, the swing member 127 rotates (swings) around the drive screw 109 and the fulcrum member 122, as shown in FIG. 2 (d). The rotation of the fulcrum member 122 transmits a rotational torque to the drive screw 109 via the one-way clutch 121 in this direction to rotate the drive screw 109.

When the drive screw 109 rotates as described above, when the drive screw 109 is turned into a right-hand thread, the drive screw 109 is pushed by the female screw member 106 to increase the tension of the wire 117, that is, FIG. b) Move to the left. The tip of the drive screw 109 has a step portion 125, and the step portion 125 engages with a part of the second drive screw bearing 128 or the second drive screw bearing support member 129, and guides the entire driven wheel unit 105 to the guide rail. It is moved to the left in FIG. 2B along 103. As a result, the distance between the pulleys increases and the tension of the wire 117 increases.

Next, the rotation of the driven wheel 104 further progresses, the roller 120 is pushed up again, and the above operation is repeated.

When the operation of increasing the tension of the wire 117 is repeated, the stress in the axial direction of the drive screw 109 becomes high, and finally the corner portion of the swing member 127 cannot be pulled down by the tensile force of the spring 124. In this state, the spring 124 extends, the roller 120 stops at the farthest point from the eccentric member 118, and the swing member 127 stops swinging.

However, when the wire 117 is stretched by use and the wire tension is reduced, and the axial stress of the drive screw 109 is reduced accordingly, the corner portion of the swing member 127 can be pulled down again by the tensile force of the spring 124. And retightening is done.

As described above, according to the second embodiment, when the wire tension decreases, retightening is automatically performed so as to increase the wire tension.

As described above, also in this embodiment, it is possible to provide a wire constant tension device having a simple mechanism and which does not require periodic manual inspection and maintenance.

Also in this embodiment, even if the rotation angle θ due to one swing of the swing member 127 is small, the retightening operation is repeated, and finally, the tension of the wire 117 reaches the set value without any problem. It is the same as the first embodiment.

According to the present embodiment, since the swing member 127 is connected to the fulcrum member 122 at its end, the swing member 127 has a simpler swing motion as compared with the seesaw-shaped swing motion. doing. Therefore, the design is simpler, the path length of the swing member 127 can be shortened, and the structure can be simplified.

Also in the second embodiment, the base plate 101 can be omitted if there is an arbitrary fixed pedestal, and the nut support member 102 is any known female as long as it can fix the female screw member 106. It may be a screw support member.

Further, the driven wheel unit 105 can have an arbitrary structure as long as it can rotatably support the driven wheel 104 and move as a whole. However, in the driven wheel 104, it is preferable that the driven wheel axle 116 is substantially perpendicular to the drive screw 109 and has substantially the same height.

Further, the swing member 127 is not limited to the one having an L-shape in a plan view, one end (first end) is connected to the fulcrum member 122, and the other end (second end) is directly connected to the eccentric member 118. Alternatively, any shape can be used as long as it can indirectly touch and move up and down. Further, the roller 120 can be a contact portion having a known arbitrary structure. Further, if the end portion of the swing member 127 can be slidably contacted with the eccentric member 118, the roller 120 can be omitted.

FIG. 3 shows the wire constant tension device 130 of the third embodiment. Specifically, FIG. 3A is a plan view of the wire constant tension device 130, FIG. 3B is a side view of the wire constant tension device 130, and FIG. 3C is an S arrow view of FIG. 3B. A side view of the wire constant tension device 130 in the direction, FIG. 3 (d) shows a side view of the wire constant tension device 130 in the direction of T arrow in FIG. 3 (b).

In the following description, the same parts as those in the first embodiment will be described with the same reference numerals. In addition, duplicate explanations may be summarized or omitted as appropriate.

The nut support member 102 of the first embodiment is arranged on the side (drive wheel side) on which the wire 117 is hung with respect to the driven wheel 104, whereas the wire constant tension device 130 of the third embodiment is The nut support member 102 is arranged on the side opposite to the side (driving wheel side) on which the wire 117 is hung with respect to the driven wheel 104.

In order to increase the tension of the wire 117, in the first embodiment, the drive screw 109 is retightened in the direction of compressing, whereas in the third embodiment, the drive screw 109 is retightened in the direction of stretching. Will be done.

In the wire constant tension device 130, the nut support member 102 and the guide rail 103 are fixed on the base plate 101, and the driving wheel unit 105 is slidably provided on the guide rail 103, as in the first embodiment. A driven wheel 104 is rotatably supported on the driven wheel unit 105, and a wire 117 is hung around the driven wheel 104. However, the wire 117 extends toward a drive wheel (not shown) on the side opposite to the nut support member 102 (on the left side in FIG. 3B) with respect to the driven wheel 104.

Since the winding directions of the wires 117 are opposite to each other, the arrangement of the eccentric member 118 and the swing member 131 of the present embodiment is symmetrical with the arrangement of the first embodiment.

The eccentric member 118 is fitted to the upper end of the driven wheel set 116 in FIG. 3A.

The rocking member 131 extends along the upper side wall 112 and the front wall 113 in FIG. 3A.

A spring 124 is hung between a first end portion of the swing member 131 extending downward in FIG. 3A and a bracket 123 extending from a part of the driven wheel unit 105.

The second end of the rocking member 131 extending to the left in FIG. 3A has a roller 120 that comes into contact with the eccentric member 118.

In the wire constant tension device 130 as well, as in the wire constant tension device 100 of the first embodiment, when the driven wheel 104 rotates, the eccentric member 118 rotates and pushes down the second end portion of the swing member 131. As a result, the first end portion of the swing member 131 rises against the tensile force of the spring 124. Next, when the second end portion of the swing member 131 comes into contact with the peripheral surface portion close to the center of the eccentric member 118, if the wire tension is low, the spring 124 overcomes the wire tension and the swing member 131 is the first. Pull down the two ends to rotate the drive screw 109.

However, in the third embodiment, the drive screw 109 moves to the right in FIG. 3 (a) due to the rotation of the drive screw 109, and the driven wheel unit 105 moves to the right in FIG. 3 (a) via the locking portion 132. Pulled in the direction. As a result, the tension of the wire 117 increases.

Also in the wire constant tension device 130 of the third embodiment, while the tension of the wire 117 is low, the swing member 131 swings, and the operation of retightening the drive screw 109 is repeated. When the tension of the wire 117 reaches a predetermined value, the swinging member 131 stops swinging with the spring 124 extended. However, when the tension of the wire 117 is reduced again by use, the tensile force of the spring 124 overcomes the wire tension and starts the operation of retightening the drive screw 109.

Therefore, also in the present embodiment, it is possible to provide a wire constant tension device having a simple mechanism and which does not require periodic manual inspection and maintenance.

The base plate 101 can be an arbitrary pedestal, the nut support member 102 can be an arbitrary female screw support member, and the driven wheel unit 105 has an arbitrary structure as long as it can move while rotatably supporting the driven wheel 104. It is possible, the rocking member 119 can have an arbitrary shape, and the like, as in the first embodiment.

FIG. 4 shows the wire constant tension device 135 of the fourth embodiment in which the swing member is composed of a first swing member and a second swing member, and a second fulcrum is provided in a part of the second swing member. There is.

Since the fourth embodiment has many structures and members in common with the third embodiment of FIG. 3, the same parts are designated by the same reference numerals and duplicate description will be omitted. Hereinafter, only the different structures will be described.

The arrangement of the eccentric member 118 and the swing member of the present embodiment is symmetrical with the arrangement of the third embodiment. The swing member of the wire constant tension device 135 includes a first swing member 136 and a second swing member 137.

The first swing member 136 is arranged along the front wall 113 of the driven wheel unit 105. The back side of the paper surface of the first rocking member 136 in FIG. 4 is connected to the fulcrum member 122.

The second swing member 137 is arranged along the side wall 112 of the driven wheel unit 105. The left end of the second rocking member 137 in FIG. 4 has a roller 120. The roller 120 is in contact with the eccentric member 118. The right end of the second rocking member 137 in FIG. 4 is connected to the front end of the first rocking member 136 in FIG. 4 by a pivot joint. A second fulcrum member 138 is provided in the middle portion of the second swing member 137. The second fulcrum member 138 preferably consists of a pin erected on the side wall 112. The second swing member 137 swings like a seesaw with the second fulcrum member 138 as a fulcrum.

The spring 124 is provided on the front side of the paper surface in FIG. 4 with respect to the fulcrum member 122. One end of the spring 124 rests on the right end of FIG. 4 of the second swing member 137 or the front end of the paper surface of FIG. 4 of the first swing member 136 (both are referred to as the first end). ..

When the roller 120 at the second end of the second swing member 137 is pushed down by the eccentric member 118, the spring 124 is stretched and operates in the same manner as in the third embodiment. When the second end of the second swing member 137 comes into contact with the peripheral surface portion near the center of the eccentric member 118, if the wire tension is low, the spring 124 overcomes the wire tension and the first end of the swing member The part is pulled down and the drive screw 109 is rotated.

Needless to say, also in the first embodiment, the wire constant tension device can be similarly realized by arranging the eccentric member 118, the swing member and the spring 124 symmetrically with each other in the fourth embodiment.

FIG. 5 shows a wire feeding device 150 to which the wire constant tension device 100 is applied.

The wire feeding device 150 is built on a common base 151. The take-up and unwind drum 152, which is one of the drive wheels, is rotatably supported from the base 151. The take-up and unwind drum 152 has a drive shaft 153, and the drive shaft 153 is connected to the servomotor 155 via a speed reducer 154. The take-up / unwind drum 152 is rotationally driven by the servomotor 155 while controlling the rotation angle.

The wire constant tension device 100 is configured such that the base plate 101 is fixed to the base 151 and the driven wheel 104 is located at substantially the same height in the same plane as the wire take-up and unwind surface of the take-up and unwind drum 152. Has been done.

The driven wheel 104 is mounted on the driven wheel unit 105. The driven wheel unit 105 can slide on the base plate 101 so that the driven wheel 104 moves in the same plane. The nut support member 102 is arranged between the driven wheel unit 105 and the take-up and unwind drum 152.

A wire 117 is hung between the driven wheel 104 and the take-up / unwinding drum 152. The wire 117 is wound around the take-up and unwind drum 152 except for the part where the wire 117 is taken up and unwound. A slider 156 is fixed to a part of the wire 117. The slider 156 is configured to slide on the guide rail 157 while being pulled by the wire 117. The guide rail 157 is supported by a support 158.

When the take-up and unwind drum 152 is rotationally driven while being controlled by the servomotor 155, the slider 156 is pulled by the wire 117 and moves on the guide rail 157 while being position-controlled. Therefore, by placing or engaging the conveyed object on the slider 156, the object can be conveyed accurately and quickly.

In this wire feeding device 150, since the wire 117 is long as a whole, the phenomenon that the wire 117 is stretched and the tension is lowered for a relatively long period of time continues due to use. On the other hand, by providing the wire constant tension device 100, the wire tension can always be kept within a preferable value range without requiring manual inspection and maintenance.

Further, as is clear from FIG. 5, according to the wire constant tension device 100, the size can be reduced and the manufacturing cost can be suppressed by the simple structure.

In each of the above embodiments, the drive screw 109 is a right-hand screw, but it can be changed to a left-hand screw. In this case, in the wire constant tension device of each embodiment, the side on which the wire 117 is hung (drive wheel side) can be configured in reverse.

Further, the installation position of the spring 124 is not limited to each of the above embodiments. That is, the spring 124 can be installed at an arbitrary position of the swing member (119, 127, 131, 136, 137) if the fulcrum member 122 can be rotated and the drive screw 109 can be rotated by the rotation.

Further, the spring 124 is not limited to the tension spring. That is, the spring 124 may be a compression spring as long as it can rotate the fulcrum member 122 and thereby rotate the drive screw 109. For example, in the first, second, and fourth embodiments, the spring 124 (compression spring) and the bracket 123 are installed at positions opposite to the illustrated spring 124 (tension spring) and the bracket 123, centering on the drive screw 109. do it. Both tension springs and compression springs may be provided. The spring 124 is not limited to the coil spring and may be a spring of another form, or an elastic body other than the spring may be used instead of the spring 124.

Based on the above description, those skilled in the art may be able to conceive of additional effects and various modifications of the present invention, but the embodiments of the present invention are not limited to the above-described embodiments. Various additions, changes and partial deletions are possible without departing from the conceptual idea and purpose of the present invention derived from the contents defined in the claims and their equivalents.

The principle of the wire constant tension device according to the present invention can be applied not only to a wire feeding device but also to a device using other power transmission means such as a ring-shaped belt, a feeding device using a timing belt or a chain. .. That is, the present invention can also be provided as a constant tension device not limited to wires.

100, 126, 130, 135: Wire constant tension device 101: Base plate 102: Nut support member 103, 157: Guide rail 104, 172: Driven wheel 105: Driven wheel unit 106: Female screw member 107: Recess 108: Fixing screw 109 : Drive screw 110: Shoe 111: Bottom wall 112: Side wall 113: Front wall 114: Drive screw bearing 115: Driven wheel bearing 116, 173: Driven wheel shaft 117, 161: Wire 118, 218: Eccentric member 119, 127, 131: Swing member 120: Roller 121, 234: One-way clutch 122: Supporting point member 123: Bracket 124: Spring 125: Step portion 128: Second drive screw bearing 129: Second drive screw bearing support member 132: Locking portion 136: First rocking member 137: Second rocking member 150: Wire feeding device 151: Base 152: Winding and unwinding drum 153: Drive shaft 154: Reducer 155: Servo motor 156: Slider 158: Support body 174: Support member 182A: First transmission shaft 183a: First transmission gear 183b: Second transmission gear 192: Male screw 193: Female screw 211: Telescopic arm 231: Swing arm 233: Holding member

Claims (8)

Female screw support member and
The drive screw screwed to the female screw support member and
A driven wheel unit that rotatably supports a driven wheel around which a wire is hung, engages with the drive screw, and can move in parallel with the central axis of the drive screw.
An eccentric member that rotates with the driving wheel,
A fulcrum member that fits into the drive screw via a one-way clutch,
A swing member whose part is fixed to the fulcrum member and one end of which is slidably in contact with the eccentric member.
It has a spring that is hung between a part of the swing member and a part of the driven wheel unit.
The spring has a constant wire tension that, when the tension of the wire drops below a predetermined value, overcomes the tension of the wire and rotates the drive screw in a direction in which the tension of the wire increases. Device. The wire constant tension device according to claim 1.
The driven wheel unit supports the driven wheel so that the driven wheel axis of the driven wheel is substantially orthogonal to the driving screw and has approximately the same height.
The eccentric member is provided at one end of the driven wheel axle and is provided.
The swing member is configured to swing like a seesaw with the fulcrum member as a fulcrum.
A wire constant tension device in which the spring is hung between an end portion opposite to an end portion that is slidably in contact with the eccentric member and a part of the driven wheel unit. The wire constant tension device according to claim 1.
The driven wheel unit supports the driven wheel so that the driven wheel axis of the driven wheel is substantially orthogonal to the driving screw and has approximately the same height.
The eccentric member is provided at one end of the driven wheel axle and is provided.
In the swing member, the end opposite to the end that is slidably in contact with the eccentric member is fixedly connected to the fulcrum member.
A wire constant tension device in which the spring is hung between an end portion that is slidably in contact with the eccentric member and an end portion that is fixedly connected to the fulcrum member. The wire constant tension device according to claim 1.
The driven wheel unit supports the driven wheel so that the driven wheel axis of the driven wheel is substantially orthogonal to the driving screw and has approximately the same height.
The eccentric member is provided at one end of the driven wheel axle and is provided.
The swing member is connected to a first swing member that swings like a seesaw with the fulcrum member as a fulcrum, and a fulcrum provided in a part of the driven wheel unit, which is connected to the first swing member by a pivot joint. Including a second swinging member that swings like a seesaw with the member as a fulcrum,
The spring is hung between the end of the first swing member or the second swing member and a part of the driven wheel unit on the opposite side of the end that is in sliding contact with the eccentric member. ing,
Wire constant tension device. The wire constant tension device according to any one of claims 1 to 4.
The female screw support member is a wire constant tension device that is arranged on the same side as the side on which the wire is hung with respect to the driven wheel. The wire constant tension device according to any one of claims 1 to 4.
The female screw support member is a wire constant tension device that is arranged on the side opposite to the side on which the wire is hung with respect to the driven wheel. The wire constant tension device according to any one of claims 1 to 6.
The swing member is a wire constant tension device having a roller at an end that is slidably contacting the eccentric member. The wire constant tension device according to any one of claims 1 to 7 is included, and a wire is hung between a driven wheel of the wire constant tension device and at least one pulley including a drive wheel. Wire feeder.

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