JP2011089608A - Telescopic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a telescopic device reducing the load applied to a driving part and balancing the weight. <P>SOLUTION: The telescopic device 12 includes a driving part 18; a cylinder body 22 having a fixed cylinder 38 formed to have a regular hexagon cross section, a first movable cylinder 40 storable in the fixed cylinder 38, and a second movable cylinder 42 storable in the first movable cylinder 40, and expanding and contracting in the axial direction of the fixed cylinder 38; a first moving unit 44 for moving the first movable cylinder 40 to the axial direction of the fixed cylinder 38 under the driving action of the driving part 18; a second driving unit 46 disposed in the fixed cylinder 38 and making the second movable cylinder 42 interlock with the first movable cylinder 40 to the axial direction of the first movable cylinder 40; and a load imparting part 28 for imparting the load in the direction in which the cylinder body 22 is contracted to the first movable cylinder 40. The second moving unit 46 of the fixed cylinder 38 and the load imparting part 28 are alternately provided along a peripheral direction of the fixed cylinder 38. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a telescopic device having a plurality of cylinders provided to be extendable and contractible.

  2. Description of the Related Art Conventionally, telescopic devices that have a plurality of tubes and whose length can be displaced by relatively expanding and contracting the tubes along the longitudinal direction are widely known.

  As such a telescopic device, an inner cylinder is provided so as to be accommodated inside an outer cylinder fixed to a base, and an inner cylinder is provided so as to be accommodated inside the middle cylinder, and the middle cylinder is driven by a drive unit. It is known that the feed screw shaft is moved in the axial direction of the outer cylinder, and the inner cylinder is interlocked with the middle cylinder in the axial direction of the middle cylinder by a power transmission portion provided in the outer cylinder. (See Patent Document 1).

JP 2009-197828 A

  By the way, in the telescopic device, it is desired to reduce the load applied to the drive unit from the viewpoint of energy saving.

  In the telescopic device of Patent Document 1 described above, it is necessary to reduce the weights of the inner cylinder and the middle cylinder in order to reduce the load applied to the drive unit.

  As one method for reducing the weight of the inner cylinder and the inner cylinder, it is conceivable that the inner cylinder and the inner cylinder are made of a light material, but the cylinder needs to have high rigidity. Highly rigid and lightweight materials are required and costly.

  As another method, it is conceivable to apply a load in the direction in which the cylindrical body contracts to the middle cylinder. For example, means for applying the load in the vicinity of the power transmission portion of the outer cylinder (addition providing means) When the weight is provided, the weight of the power transmission unit and the load applying means is biased to a part of the outer cylinder, so that the weight balance of the outer cylinder is deteriorated. As a result, when the outer cylinder tilts with respect to the middle cylinder and expands and contracts the cylinder, an extra frictional force is generated in the power transmission unit, and the load on the driving unit may increase.

  Accordingly, an object of the present invention is to provide a telescopic device capable of reducing the load applied to the drive unit and achieving a weight balance.

  A telescopic device according to the present invention includes a driving means, a fixed cylinder formed in a polygonal cross section, a first movable cylinder that can be accommodated in the fixed cylinder, and a first movable cylinder that can be accommodated in the first movable cylinder. And a first moving unit that moves the first movable cylinder in the axial direction of the fixed cylinder under the driving action of the driving means. And a second moving unit that is provided in the fixed cylinder and interlocks the second movable cylinder with the first movable cylinder in the axial direction of the first movable cylinder, and a load in a direction in which the cylindrical body contracts. Load applying means for applying to the first movable cylinder, and the second moving unit of the fixed cylinder and the load applying means are alternately provided along the circumferential direction of the fixed cylinder.

  According to such a configuration, the inertial mass of the first and second movable cylinders can be reduced by applying a load in the direction in which the cylinder is contracted by the load applying means to the first movable cylinder, so that the driving means Can be reduced. Further, since the second moving unit of the fixed cylinder and the load applying means are provided alternately along the circumferential direction of the fixed cylinder, the weight of the load applying means and the second moving unit is a part of the fixed cylinder. There is no bias. In other words, the weight of the second moving unit can be balanced by the weight of the load applying means. Thereby, the weight balance of a fixed cylinder can be taken. Therefore, when the cylinder is expanded and contracted, an excessive frictional force is not generated in the second moving unit, and the load applied to the driving means does not increase.

  A plurality of the second moving units and the load applying means may be provided, and the load applying means may be provided at a position facing the second moving unit. This makes it easy to adjust the weight balance of the fixed cylinder.

  The load applying means includes a cylinder provided in the fixed cylinder, a rod portion provided in a piston movably accommodated in the cylinder and attached to the first movable cylinder, and a pressure for pressing the piston. Means.

  Then, since the rod part provided in the piston is attached to the first movable cylinder, it is possible to apply a load in the direction in which the cylindrical body contracts to the first movable cylinder by pressing the piston with the pressing means. Further, since the piston is movably accommodated in the cylinder, the load applying means does not hinder the movement of the first movable cylinder.

  You may further provide the load control part which controls operation | movement of the said press means based on the physical quantity correlated with the load concerning the said drive means.

  If it does so, since the timing which a press means presses a piston can be adjusted based on the physical quantity correlated with the load concerning a drive means, the load concerning a drive means can be made small effectively.

  The fixed cylinder may be formed in a hexagonal cross section. Thereby, compared with the case where a fixed cylinder is formed in cross-sectional circular shape or cross-sectional square shape, rigidity can be improved.

  According to the present invention, since the inertial mass of the first and second movable cylinders can be reduced by applying a load in the direction in which the cylinder is contracted by the load applying means to the first movable cylinder, it is applied to the driving means. The load can be reduced. Further, since the second moving unit of the fixed cylinder and the load applying means are provided alternately along the circumferential direction of the fixed cylinder, the weight of the load applying means and the second moving unit is a part of the fixed cylinder. The weight of the fixed cylinder can be balanced.

1 is an external perspective configuration diagram of a workpiece transfer device to which a telescopic device according to the present invention is applied. It is block explanatory drawing which shows the state which the cylinder shrink | contracted in the workpiece conveyance apparatus of FIG. It is a partially expanded sectional view of FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. It is a longitudinal cross-sectional view which shows the state which the cylinder extended in the workpiece conveyance apparatus of FIG. It is the flowchart which showed the conveyance procedure of the workpiece | work using the workpiece conveyance apparatus which concerns on this embodiment. FIG. 7A is a graph in the case where fluid is supplied from the fluid supply unit to the cylinder when the cylinder is fully extended in a graph showing a change in current of the driving unit with respect to time when the cylinder is expanded and contracted. FIG. 7B is a graph when the fluid is constantly supplied from the fluid supply unit to the cylinder, and FIG. 7C is a graph when the extension of the cylinder reaches half of the maximum extension of the cylinder. It is a graph at the time of supplying a fluid. In the graph which showed the change of the electric current of the drive part with respect to time when expanding and contracting a cylinder, it is a graph at the time of not supplying fluid to a cylinder from a fluid supply part.

  Hereinafter, preferred embodiments of the telescopic device according to the present invention will be described in detail with reference to the accompanying drawings.

  In the present embodiment, a workpiece transfer apparatus in which a telescopic device according to the present invention is incorporated will be described.

  The workpiece transfer device 10 is a device for transferring a workpiece W such as a cylinder block constituting a vehicle engine. As shown in FIG. 1, the workpiece transfer device 10 is telescopically provided with a plurality of cylinders and is telescopically provided. , A work holding part 14 capable of holding a work W provided at the tip of the cylinder and a main control part 16 are provided.

  As shown in FIGS. 1 and 2, the telescopic device 12 includes a drive unit 18 that is rotationally driven under an energization action, a load detection unit 20 that outputs a signal corresponding to a load applied to the drive unit 18, and one direction (X ), A driving force conversion unit 24 that converts the rotational driving force of the driving unit 18 into a driving force in a linear direction, a guide mechanism 26 provided in the cylindrical body 22, and the cylindrical body 22. A load applying unit 28 for applying a load in the direction of contraction (in the direction of arrow X2) to the cylindrical body 22, and a load control unit 30.

  As shown in FIG. 2, the drive unit 18 is formed of, for example, a stepping motor, and the drive shaft 32 protrudes toward the cylindrical body 22 (in the direction of the arrow X <b> 1) and is connected to the drive force conversion unit 24. Thereby, the rotational driving force output from the driving unit 18 is transmitted to the driving force converting unit 24. The drive unit 18 is connected to the upper portion of the base 36 via an attachment member 34, and the drive shaft 32 is inserted into the attachment member 34.

  The load detection unit 20 includes, for example, an encoder that detects a current (pulse current) of the drive unit 18 and is provided in the drive unit 18.

  As shown in FIG. 3, the cylindrical body 22 can be accommodated in the first movable cylinder 40, the fixed cylinder 38 fixed to the base 36, the first movable cylinder 40 provided so as to be accommodated in the fixed cylinder 38, and the first movable cylinder 40. And a second movable cylinder 42 which is provided and connected to the work holding portion 14 at an end thereof.

  As shown in FIG. 4, the fixed cylinder 38, the first movable cylinder 40, and the second movable cylinder 42 are arranged in the same direction in a state of being formed in a regular hexagonal cross section. That is, the sides of each cylinder face each other.

  As shown in FIG. 3, the driving force conversion unit 24 includes a first moving unit 44 that moves the first movable cylinder 40 in the X direction under the driving action of the driving unit 18, and the second movable cylinder 42 in the X direction. A second moving unit 46 linked to the first movable cylinder 40 is included.

  The first moving unit 44 includes a feed screw shaft 48 connected to the drive shaft 32 (see FIG. 2) of the drive unit 18, a support member 50 that rotatably holds the feed screw shaft 48, and a screw on the feed screw shaft 48. And a displacement body 52 coupled to the first movable cylinder 40.

  As shown in FIG. 2, one end of the feed screw shaft 48 is connected to the drive shaft 32 via a connecting nut 54, and rotates integrally under the rotational action of the drive unit 18. At this time, the feed screw shaft 48 is rotatably supported by being inserted into a support member 50 provided on one end side. A ring member 55 that prevents the displacement body 52 from coming off the feed screw shaft 48 is provided at the end of the feed screw shaft 48 in the X1 direction.

  As shown in FIGS. 3 and 4, three second moving units 46 are provided at equal intervals in the circumferential direction of the cylindrical body 22, and a first rack 56 provided in the fixed cylinder 38 and a second movable unit 46. A second rack 58 is provided on the cylinder 42 and faces the first rack 56, and a pinion unit 60 is provided on the first movable cylinder 40.

  The first rack 56 and the second rack 58 are formed in a block shape having a predetermined length along the X direction, and tooth portions 56a and 58a are formed on one side surface thereof. The first rack 56 is arranged such that the tooth portion 56a faces the inner side (center A side) of the cylindrical body 22, and the second rack 58 has the tooth portion 58a facing the outer side of the cylindrical body 22. Has been placed. A notch 59 is formed at a position facing the first rack 56 of the first movable cylinder 40 (see FIG. 3).

  The pinion unit 60 includes a bearing 62 fixed to the first movable cylinder 40 and a pinion gear 66 that is rotatably supported by the bearing 62 via a shaft 64. The pinion gear 66 is meshed with each of the tooth portions 56a and 58a (see FIG. 3) of the first rack 56 and the second rack 58.

  As shown in FIG. 4, one guide mechanism 26 is provided between the second moving units 46, that is, three guide mechanisms 26, and a first guide portion 68 that guides the first movable cylinder 40 in the X direction, And a second guide part 70 for guiding the second movable cylinder 42 in the X direction. The first guide part 68 and the second guide part 70 are respectively arranged at positions offset in the circumferential direction of the cylindrical body 22.

  The first guide portion 68 is provided on a first guide rail 72 provided on the outer surface of the first movable cylinder 40 and extending in the X direction, and a first guide rail 72 fixed to the inner surface of the fixed cylinder 38 via a bracket 74. Engaging first slide 76.

  As shown in FIGS. 3 and 4, the second guide portion 70 is provided on the outer surface of the second movable cylinder 42 and is provided on the inner surface of the first movable cylinder 40 and the second guide rail 78 extending in the X direction. And a second slide 80 engaged with the second guide rail 78.

  As shown in FIG. 4, the load applying unit 28 is provided at a position facing the second moving unit 46 of the fixed cylinder 38, in other words, adjacent to the first guide unit 68. That is, three load applying units 28 are provided. As shown in FIGS. 2 to 4, the load applying unit 28 includes a cylinder 82 that is fixed to the outer surface of the fixed cylinder 38 and extends in the X direction, a piston 84 that is movably accommodated in the cylinder 82, and a piston 84. A piston rod 86 extending in the X1 direction, a fluid supply portion 88 as a pressing means for supplying fluid into the cylinder 82, and a fluid passage connecting the fluid supply portion 88 and the end portion on the X1 side of the cylinder 82 90.

  As shown in FIG. 3, a discharge hole 92 for discharging the air in the cylinder 82 is formed at the end portion of the cylinder 82 on the X2 side, and a piston rod 86 is inserted into the end portion of the cylinder 82 on the X1 side. An insertion hole 94 is formed. Note that one end of the piston rod 86 is connected to the outer surface of the first movable cylinder 40.

  The fluid supplied by the fluid supply unit 88 may be a gas or a liquid. In the case of using gas, for example, compressed air or the like is used.

  As shown in FIG. 2, the load control unit 30 controls the operation of the fluid supply unit 88. The load control unit 30 is provided in the main control unit 16.

  As shown in FIGS. 1 to 3, the work holding portion 14 is connected to the holder 96 via a base plate 98 and a holder 96 provided at the end of the second movable cylinder 42 on the X1 side to hold the work W. It has a possible hand unit 100 and a rotational drive source 102 that rotationally drives the hand unit 100 via a holder 96.

  The holder 96 is formed in a cylindrical shape and is held by the second movable cylinder 42 via the plate 104. A rotation drive source 102 is provided on the upper portion of the holder 96. The rotation drive source 102 is formed of, for example, a stepping motor, and is fixed to the end portion on the X1 side of the second movable cylinder 42 via a mounting bracket (not shown). The

  Further, since the hand portion 100 is provided at the lower end portion of the holder 96 via the base plate 98, the hand portion 100 is rotationally driven via the holder 96 and the base plate 98 under the rotating action of the rotation drive source 102.

  The hand unit 100 is a pair of holding arms 105 provided so as to be openable and closable with respect to the base plate 98, a pair of arm guides 106 for guiding the holding arms 105 along the base plate 98, and an arm for opening and closing the holding arms 105. Cylinder 108.

  The holding arm 105 is formed in a substantially T-shaped cross section, and its upper part is engaged with the arm guide 106 so as to be able to approach and separate from each other. That is, when the workpiece W is held, the pair of holding arms 105 is displaced along the arm guide 106 under the driving action of the arm cylinder 108, and the workpiece W is held by holding the workpiece W by the holding arms 105. The

  As shown in FIG. 2, the main control unit 16 controls the drive unit 18, the rotation drive source 102, and the arm cylinder 108. The main control unit 16 includes the load control unit 30, the storage unit 110, the load determination unit 112, the position calculation unit 114, and the position determination unit 116 described above.

The storage unit 110 stores a predetermined threshold value I ₀ and cylindrical body expansion data L ₀ . The threshold value I ₀ is determined in advance based on the weight of the cylindrical body 22 and the like through experiments. As the cylinder elongation data L ₀ , the elongation amount from the initial state of the cylinder 22 when the workpiece holding unit 14 is in a position where the workpiece W can be held is used (see FIG. 5). Here, the initial state refers to a state in which the cylindrical body 22 is completely contracted (state in FIG. 2). Further, the threshold value I ₀ and the cylindrical body extension data L ₀ may be stored in the storage unit 110 when an operator or the like inputs from an input unit (not shown).

The load determination unit 112 determines whether or not the current value I _a acquired with reference to the output signal from the load detection unit 20 is larger than the threshold value I ₀ of the storage unit 110.

Position calculating unit 114 calculates the elongation amount L _a of the cylindrical body 22 (see FIG. 5). Specifically, the position calculation unit 114 calculates the extension amount of the cylindrical body 22 from the initial state based on the current value (pulse signal) acquired with reference to the output signal from the load detection unit 20.

Position determination unit 116 determines whether the elongation amount L _a of the cylindrical body 22 calculated by the position calculation section 114 matches the cylindrical body extending data L ₀ stored in the storage unit 110.

  Next, a procedure for conveying the workpiece W using the workpiece conveyance device 10 according to the present embodiment will be described with reference to the flowchart of FIG.

  First, the work conveyance device 10 provided to be movable on the rail R is set to a predetermined position (above the work W) (step S1). At this time, the workpiece transfer apparatus 10 is in an initial state.

  Thereafter, the main control unit 16 drives the drive unit 18 to extend the cylindrical body 22 (step S2). Specifically, the main control unit 16 controls the drive unit 18 so that, for example, the drive shaft 32 of the drive unit 18 rotates in a predetermined direction (for example, clockwise). Then, the feed screw shaft 48 connected to the drive shaft 32 via the connection nut 54 rotates in the clockwise direction, and the displacement body 52 moves in the X1 direction. The first movable cylinder 40 connected to the displacement body 52 moves in the X1 direction while being guided by the first guide portion 68, and the pinion gear 66 provided on the first movable cylinder 40 is a first rack 56. And it rotates in the clockwise direction (arrow B direction) while meshing with the second rack 58. Accordingly, the pinion gear 66 pushes down the tooth portion 58a of the second rack 58 in the X1 direction with the tooth portion 56a of the first rack 56 as a fulcrum, so that the second movable cylinder 42 moves in the X1 direction. Therefore, the first movable cylinder 40 protrudes from the fixed cylinder 38 in the X1 direction, and the second movable cylinder 42 protrudes from the first movable cylinder 40 in the X1 direction. As a result, the cylindrical body 22 extends.

Further, the main control unit 16 detects a load applied to the drive unit 18 (step S3). Specifically, the main control unit 16 refers to the signal output from the load detection unit 20 and acquires the current value I _a flowing through the drive unit 18. Here, the current value I _a is proportional to the load applied to the driving unit 18.

Subsequently, the load determination unit 112 determines whether or not the current value I _a detected by the load detection unit 20 is larger than _a predetermined threshold value I ₀ (step S4). If the current value I _a is the threshold value I ₀ or less (step S4: No), the procedure returns to step S3.

On the other hand, when the current value I _a is larger than the threshold value I ₀ (step S4: Yes), the load control unit 30 controls the fluid supply unit 88 supplies fluid to the cylinder 82 (step S5). Then, since the piston 84 is pressed in the X2 direction by the fluid supplied into the cylinder 82, a load in the direction in which the cylindrical body 22 contracts (X2 direction) is applied to the first movable cylinder 40. Thereby, since the inertial mass of the 1st movable cylinder 40 and the 2nd movable cylinder 42 becomes small, the load concerning the drive part 18 can be reduced. That is, the drive unit 18 can expand and contract the cylindrical body 22 with less energy (current) than when the load is not applied to the first movable cylinder 40. Note that the pressure of the fluid supplied by the fluid supply unit 88 is set such that the piston 84 does not move in the X2 direction in the cylinder 82. Therefore, the piston 84 can be moved in the X1 direction while pressing the piston 84 in the X2 direction, so that the first movable cylinder 40 and the second movable cylinder 42 can be moved smoothly.

Then, the position determination unit 116, elongation amount L _a of the cylindrical body 22 determines whether or not consistent with the tubular body extending data L ₀ (step S6). Elongation amount L _a of the tubular body 22, the value calculated by the position calculating unit 114 is used. If elongation amount L _a of the tubular body 22 does not coincide with the cylindrical body extending data L ₀ (step S6: No), the procedure repeats step S6. This is because the cylindrical body 22 has not yet extended to a position where the workpiece holding portion 14 can hold the workpiece W.

On the other hand, if the elongation amount L _a of the cylindrical member 22 matches the cylindrical body extending data L ₀ (step S6: Yes), the main control unit 16 stops the operation of the driving unit 18 (step S7). Then, the main control unit 16 controls the rotational drive source 102 and the arm cylinder 108 to hold the workpiece W (step S8).

  Thereafter, the main control unit 16 drives the driving unit 18 to contract the cylindrical body 22 (step S9). Specifically, the main control unit 16 controls the drive unit 18 so that the drive shaft 32 of the drive unit 18 rotates counterclockwise. Then, the first movable cylinder 40 moves in the X2 direction, the pinion gear 66 rotates counterclockwise (arrow C direction), and the second movable cylinder 42 moves in the X2 direction. The operating principle for contracting the cylindrical body 22 is the same as the operating principle for extending the cylindrical body 22 described above, and a detailed description thereof will be omitted.

  Subsequently, the workpiece transfer apparatus 10 holding the workpiece W is moved to the transfer position by the rail R (step S10). After the completion of this procedure, the conveyance of the current work W is completed.

Next, the effect of this embodiment is demonstrated, referring FIG. 7A-FIG. 7C. 7A to 7C are graphs showing changes in the current of the drive unit 18 with respect to time when the cylinder 22 is expanded and contracted, and FIG. 7A is a fluid supply unit 88 when the cylinder 22 is fully extended. 7B shows a graph (solid line A) when fluid is supplied to the cylinder 82 from FIG. 7, FIG. 7B shows a graph (solid line B) when fluid is always supplied from the fluid supply unit 88 to the cylinder 82, and FIG. The graph (solid line C) when the fluid is supplied from the fluid supply unit 88 to the cylinder 82 when the elongation of the body 22 reaches half of the maximum elongation of the cylindrical body 22 (L _a = 0.5L ₀ ) is shown. Yes. That is, in FIG. 7A-7C, the timing which supplies the fluid from the fluid supply part 88 to the cylinder 82 differs.

  7A to 7C, a one-dot chain line D indicates a waveform obtained when the fluid is not supplied from the fluid supply unit 88, and time T1 indicates a time when the cylindrical body 22 is fully extended. Time T <b> 2 indicates a time when the elongation of the cylinder 22 reaches half of the maximum elongation of the cylinder 22.

  As can be understood from FIG. 7A, when the fluid is supplied from the fluid supply unit 88 to the cylinder 82 when the cylindrical body 22 is fully extended, the drive unit 18 is more than the one-dot chain line D after the time T1. A small current is flowing. Here, for example, the power consumption of the drive unit 18 when the cylinder 22 is expanded and contracted without supplying fluid from the fluid supply unit 88 to the cylinder 82 is the integral value of the alternate long and short dash line D (hatched in FIG. 8). It can be seen that the power consumption of the drive unit 18 is suppressed after the time T1.

  Further, as can be seen from FIG. 7B, when fluid is always supplied from the fluid supply unit 88 to the cylinder 82, a current larger than the one-dot chain line D flows through the drive unit 18 before time T2, and from time T2. Later, a current smaller than that of the alternate long and short dash line D flows through the drive unit 18. That is, it can be seen that the power consumption of the drive unit 18 has increased before the time T2.

  Furthermore, as understood from FIG. 7C, when the fluid is supplied from the fluid supply unit 88 to the cylinder 82 when the extension of the cylinder 22 reaches half of the maximum extension of the cylinder 22, before the time T2, The same current as the one-dot chain line D flows through the drive unit 18, and less current than the one-dot chain line flows through the drive unit 18 after time T2. That is, in this case, it can be seen that the power consumption of the drive unit 18 is minimized.

  In the telescopic device 12 according to the present embodiment, the cylinders 82 and the second moving units 46 are alternately provided along the circumferential direction of the fixed cylinder 38, so that the weights of the load applying unit 28 and the second moving unit 46 are fixed. There is no bias toward a part of the tube 38. In other words, the weight of the second moving unit 46 can be balanced by the weight of the load applying unit 28. Thereby, the weight balance of the fixed cylinder 38 can be taken. Therefore, when the cylindrical body 22 is expanded and contracted, the fixed cylinder 38 is inclined with respect to the first movable cylinder 40, so that an extra frictional force is generated in the second moving unit 46 and the load applied to the drive unit 18 is increased. Can be blocked. Further, as compared with the case where a plurality of cylinders are provided adjacent to each other, a load can be uniformly applied to the first movable cylinder 40. Furthermore, since the three cylinders 82 are provided, the capacity of each cylinder 82 can be reduced (weighted) as compared with the case where only one cylinder is provided, so that the weight balance of the fixed cylinder 38 can be adjusted. It becomes easy to take.

  According to the present embodiment, since the load applying portion 28 is provided at a position facing the second moving unit 46 of the fixed cylinder 38, the balance of the fixed cylinder 38 can be easily adjusted.

  In addition, although this embodiment showed the example of a regular hexagonal shape, a regular tetragonal shape may be used. In that case, the plurality of second moving units 46 are provided at positions facing each other, and the phase of the second moving unit 46 is shifted by 90 ° between one second moving unit 46 and the other second moving unit 46. If the plurality of cylinders 82 are arranged to face each other, the weight balance of the fixed cylinder 38 can be easily adjusted.

  Needless to say, when there is one second moving unit 46 and one cylinder 82, the cylinder 82 may be provided at a position facing the second moving unit 46.

  In the present embodiment, since the timing of supplying the fluid from the fluid supply unit 88 is performed based on the detection result of the load detection unit 20, the load applied to the drive unit 18 can be effectively reduced.

  In the present embodiment, since the fixed cylinder 38, the first movable cylinder 40, and the second movable cylinder 42 are formed in a regular hexagonal cross section, these cylinders are formed in a circular cross section or a quadrangular cross section. As compared with the above, the rigidity of the cylindrical body 22 can be increased.

  The present invention is not limited to the above-described embodiment, and can be implemented in various forms. The fixed cylinder, the first movable cylinder, and the second movable cylinder are not limited to the example having a regular hexagonal cross section, and can be formed in various shapes. These cylinders may be formed in a polygonal cross section such as a hexagonal cross section, an octagonal cross section, or a dodecagonal cross section. In this case, the rigidity can be increased as compared with the case where the cylinder is formed in a circular cross section.

  Further, the position calculation unit is not limited to the example of calculating the extension amount of the cylinder from the current (pulse signal) of the load detection unit. The position calculation unit may calculate the extension amount of the cylinder based on the elapsed time from when the main control unit drives the drive unit.

  In the present invention, the load control unit may control the fluid supply unit based on a physical quantity correlated with the load applied to the drive unit. Therefore, the slope (differential value) of the analog current flowing through the drive unit may be used as the physical quantity.

  The load control unit may control the fluid supply unit such that the pressure of the fluid supplied to the cylinder is adjusted according to the expansion and contraction state of the cylinder.

  The telescopic device according to the present invention is not limited to an example applied to a workpiece transfer device, and can be applied to various devices.

DESCRIPTION OF SYMBOLS 10 ... Work conveying apparatus 12 ... Telescopic apparatus 14 ... Work holding part 16 ... Main control part 18 ... Drive part 20 ... Load detection part 22 ... Cylindrical body 24 ... Driving force conversion part 26 ... Guide mechanism 28 ... Load application part 30 ... Load Control part 38 ... Fixed cylinder 40 ... 1st movable cylinder 42 ... 2nd movable cylinder 44 ... 1st moving unit 46 ... 2nd moving unit 82 ... Cylinder 84 ... Piston 86 ... Piston rod (rod part) 88 ... Fluid supply part ( Pressing means)
R ... Rail W ... Workpiece

Claims (5)

Driving means;
A fixed cylinder having a polygonal cross section; a first movable cylinder that can be accommodated in the fixed cylinder; and a second movable cylinder that can be accommodated in the first movable cylinder; and the fixed cylinder A cylinder that expands and contracts in the axial direction of the cylinder;
A first moving unit for moving the first movable cylinder in the axial direction of the fixed cylinder under the driving action of the driving means;
A second moving unit provided on the fixed cylinder and interlocking the second movable cylinder with the first movable cylinder in the axial direction of the first movable cylinder;
Load applying means for applying a load in a direction in which the cylindrical body is contracted to the first movable cylinder,
The telescopic device, wherein the second moving unit of the fixed cylinder and the load applying means are provided alternately along a circumferential direction of the fixed cylinder. The telescopic device according to claim 1,
A telescopic device comprising a plurality of the second moving unit and the load applying means, wherein the load applying means is provided at a position facing the second moving unit. The telescopic device according to claim 2,
The load applying means includes a cylinder provided in the fixed cylinder,
A rod portion attached to the first movable cylinder provided on a piston movably accommodated in the cylinder;
And a pressing means for pressing the piston. The telescopic device according to claim 3,
The telescopic device further comprising a load control unit that controls an operation of the pressing unit based on a physical quantity correlated with a load applied to the driving unit. The telescopic device according to any one of claims 1 to 4,
The telescopic device, wherein the fixed cylinder is formed in a hexagonal cross section.

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