Workstation device

Abstract

A worktable device includes a worktable (2) that places a workpiece (Wa), a support mechanism (10) that supports the worktable (2) swingably about a rotational axis (15, 16), a first drive motor (20) that rotates the rotational axis (15) of the support mechanism (10) to swing the worktable (2), a balance imparting mechanism (30) that imparts a balance load corresponding to a swing position of the worktable (2) to the rotational axis (15), and a control device (50) that controls the first drive motor (20). The balance imparting mechanism (30) includes an eccentric plate (31) that has a circular plate shape and is connected to the rotational axis (15) at a position eccentric from a center position, a housing (32) that holds an outer peripheral portion of the eccentric plate (31) via a bearing (33), and a load imparting portion (35) that imparts a balance load in a direction intersecting an axis line of the rotational axis (15) to the housing (32).

Description

Technical Field

[0001] The present invention relates to a worktable device having a worktable having a mounting surface for placing workpieces, and configured to allow the worktable to swing. Background Technology

[0002] Currently, the aforementioned worktable device is mainly installed on machine tools. For example, the worktable swings around a rotation axis parallel to its mounting surface, while processing the workpiece placed on the worktable. Thus, it is possible to process complex shapes on the workpiece.

[0003] However, in this type of worktable device, the worktable is typically configured to oscillate by rotating the axis of rotation using a drive motor. Therefore, when the worktable oscillates, a torque generated by its own weight—that is, a torque corresponding to the oscillation angle of the worktable (unbalanced torque)—acts on the drive motor. Consequently, the drive motor needs to be a high-output motor capable of withstanding this unbalanced torque. However, using a high-output motor not only increases the cost of the worktable device but also increases the size of the motor, thus creating the problem of the worktable device becoming excessively large.

[0004] Therefore, in order to solve this problem, the following patent documents have proposed a balancer device for a rotating shaft that makes the counter-torque, such as the unbalanced torque, act on the rotating shaft, and the following patent documents have proposed an indexing device that makes the counter-torque, such as the unbalanced torque, act on the rotating shaft.

[0005] Specifically, the balancer device disclosed in Patent Documents 1 and 2 includes an auxiliary torque generating device that generates an auxiliary torque that counteracts at least a portion of the unbalanced torque acting on a rotating shaft. The auxiliary torque generating device comprises: a cam member fixed to the rotating shaft; a cam follower member that abuts against and follows the cam member; and a force-applying device that applies a force to the cam follower member towards the cam member, thereby causing the auxiliary torque to act on the rotating shaft via the cam member. According to this balancer device, the auxiliary torque that counteracts at least a portion of the unbalanced torque is acted on the rotating shaft via the cam member by the force-applying device.

[0006] Furthermore, the tilting indexing device disclosed in Patent Documents 3 and 4 comprises: a frame having a platform and a pair of support platforms erected at intervals on the platform; a pair of rotating shafts respectively supported on the pair of support platforms and supported so as to be rotatable relative to the corresponding support platforms via bearings; a worktable having a base for placing a workpiece and a pair of arms supporting the base, and the pair of arms being supported by the pair of rotating shafts; a drive device disposed on at least one of the pair of support platforms and driving the worktable to rotate via the rotating shafts; and a torque compensation device that compensates for unbalanced torque applied to the rotating shafts when the worktable is in a tilted state.

[0007] Furthermore, at least one of the pair of rotating shafts is configured as an eccentric shaft, which has: a pair of shaft portions whose axes coincide when viewed in the axial direction of the shaft portions and are spaced apart in the axial direction; an eccentric portion located between the pair of shaft portions in the axial direction and positioned eccentrically relative to the axis of the shaft portions; and a support portion connecting the pair of shaft portions to the eccentric portion. The eccentric shaft is supported on corresponding support platforms in each of the pair of shaft portions via bearings. The torque compensation device is connected to the eccentric portion of the eccentric shaft, which is the rotating shaft. Additionally, the torque compensation device is configured as a fluid pressure cylinder, with its rod connected to the eccentric portion of the eccentric shaft.

[0008] According to the tilting indexing device, the torque used to compensate for the unbalanced torque acting on the rotating shaft is applied to the rotating shaft through a torque compensation device composed of a fluid pressure cylinder, thereby mitigating the unbalanced torque acting on the rotating shaft.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2016-168641

[0012] Patent Document 2: Japanese Patent Application Publication No. 2017-30100

[0013] Patent Document 3: Japanese Patent Application Publication No. 2017-56508

[0014] Patent Document 4: Japanese Patent Application Publication No. 2017-56509 Summary of the Invention

[0015] The problem that the invention aims to solve

[0016] However, the existing balancer devices and tilting indexing devices described above have the following problems: The balancer device is a structure in which the outer peripheral surface of a cam component with a circular cross-section and the outer peripheral surface of a cam follower component with a similarly circular cross-section make line contact. Therefore, the load tends to concentrate at this contact point, leading to problems such as damage to the cam component and cam follower component under conditions of large unbalanced torque. Therefore, existing balancer devices are not suitable for large worktable devices that generate large unbalanced torques.

[0017] In addition, in recent years, worktable devices have been equipped with clamping mechanisms and various sensors for automatically clamping workpieces placed on the worktable. Piping and wiring are connected to these clamping mechanisms and sensors. Moreover, the piping and wiring are configured with hollow shafts forming rotating shafts for swinging the worktable, inserted into the hollow portion, and respectively connected to the clamping mechanism and sensors.

[0018] However, the tilting indexing device is configured such that the front end of the rod of a fluid pressure cylinder, which serves as a torque compensation device, is connected to the eccentric portion of the eccentric shaft, which is the rotation axis. This front end of the rod rotates around the central axis of the rotation axis. In other words, the front end of the piston rod moves in a circular motion intersecting the central axis of the rotation axis. Therefore, even if the rotation axis is hollow, piping and wiring cannot pass through the hollow portion from the outside. Consequently, the existing tilting indexing device cannot accommodate an automatic clamping mechanism and various sensors on the worktable.

[0019] The present invention was developed in view of the above actual situation, and its purpose is to provide a workbench device that can cope with larger unbalanced torque than before, and can also allow piping and wiring to be inserted into the hollow rotating shaft.

[0020] Technical solutions for solving the problem

[0021] The present invention provides a worktable apparatus for solving the above-mentioned problems, comprising:

[0022] A worktable on which workpieces are placed;

[0023] A support mechanism having a rotating shaft that freely supports the worktable by pivoting about the axis of the rotating shaft;

[0024] A first drive motor rotates the rotating shaft of the support mechanism, thereby causing the worktable to oscillate.

[0025] A balancing mechanism applies a balancing load to the rotating shaft corresponding to the swing position of the worktable.

[0026] The control device controls the first drive motor.

[0027] The balancing mechanism is configured to have:

[0028] An eccentric plate, which is circular in shape, is connected to the rotating shaft at an off-center position from the center.

[0029] The housing, which holds the outer periphery of the eccentric plate via bearings;

[0030] The load-applying part applies a balanced load to the housing in a direction intersecting the axis of the rotation shaft.

[0031] According to this worktable device, by rotating the rotating shaft using a first drive motor under the control of the control device, the worktable can be oscillated around the rotating shaft. Furthermore, at this time, a balancing load corresponding to the unbalanced torque is applied to the rotating shaft from the load-applying section via an eccentric plate. This mitigates the unbalanced torque acting on the first drive motor.

[0032] Furthermore, the outer periphery of the eccentric plate is held by the housing via bearings, thus distributing the balancing load onto the eccentric plate. Therefore, a larger balancing load than before can be applied to the eccentric plate, and even under such a large balancing load, the eccentric plate is unlikely to be damaged.

[0033] Furthermore, as the rotating shaft rotates, the eccentric plate also rotates around the central axis of the rotating shaft. However, the outer casing only moves up and down with the rotation of the eccentric plate and does not perform a circular motion that intersects the central axis of the rotating shaft. Therefore, by constructing the rotating shaft with a hollow shaft and forming an opening on the eccentric plate corresponding to the hollow portion, piping and wiring can be inserted into the hollow portion of the rotating shaft through this opening. With such piping and wiring, an automatic clamping mechanism and various sensors can be mounted on the worktable.

[0034] Furthermore, in this invention, the rotation axis of the support mechanism can be arranged parallel to the mounting surface of the worktable.

[0035] In addition, in this invention, the load-applying part can be configured as a hydraulic cylinder, the cylinder part of which is connected to the housing, and the piston rod of which is supported by a support member. The connection between the cylinder part and the housing, or the connection between the piston rod and the support member, is connected so that they can reciprocate relative to each other.

[0036] In addition, in this invention, the load-applying part can be configured as a hydraulic cylinder, the piston rod of which is connected to the housing, and the cylinder is supported by a support member, wherein the connection between the piston rod and the housing, or the connection between the cylinder and the support member, is connected to be relatively movable.

[0037] According to the two methods of worktable device, a certain pressure of hydraulic fluid is supplied to the hydraulic cylinder, thereby giving the rotating shaft a balanced load corresponding to the unbalanced torque.

[0038] Furthermore, in this invention, the load-applying unit can be configured as follows: a ball screw rotatably supported at the center of an axis and one end of which is connected to the housing; a ball nut screwed to the ball screw; a support member supporting the ball nut; and a second drive motor that rotates the ball screw.

[0039] The second drive motor is controlled by the control device.

[0040] The connection between the housing and the ball screw is configured to allow relative reciprocation.

[0041] According to the worktable device of this method, under the control of the control device, the second drive motor is driven. When the ball screw is rotated by the drive motor, the ball screw moves axially according to the engagement relationship with the ball nut, and the rotating shaft is given a balanced load corresponding to the thrust through the housing and the eccentric plate.

[0042] Moreover, in this case, by monitoring the load acting on the first drive motor and controlling the output of the second drive motor in such a way that the load becomes a load within a predetermined allowable range, the control device can apply a more rigorous balanced load to the first drive motor to counteract the unbalanced torque acting on the first drive motor, thereby more appropriately mitigating the unbalanced torque acting on the first drive motor.

[0043] Invention Effects

[0044] According to the present invention, a balancing load corresponding to the unbalanced torque is applied to the rotating shaft that causes the worktable to swing via an eccentric plate, thereby mitigating the unbalanced torque acting on the first drive motor.

[0045] Furthermore, the outer periphery of the eccentric plate is held by the housing via bearings, thus dispersing the balancing load on the eccentric plate. Therefore, a larger balancing load can be applied to the eccentric plate than before, and even under such a large balancing load, the eccentric plate is unlikely to be damaged.

[0046] Furthermore, as the rotating shaft rotates, the eccentric plate also rotates around the central axis of the rotating shaft. However, the outer casing only moves up and down with the rotation of the eccentric plate and does not perform a circular motion that intersects the central axis of the rotating shaft. Therefore, by constructing the rotating shaft with a hollow shaft and forming an opening on the eccentric plate corresponding to the hollow portion, piping and wiring can be inserted into the hollow portion of the rotating shaft through this opening. With such piping and wiring, an automatic clamping mechanism and various sensors can be mounted on the worktable. Attached Figure Description

[0047] Figure 1 This is a front view of a workbench device according to a partial cross-section of an embodiment of the present invention.

[0048] Figure 2 This is an explanatory diagram showing the schematic structure of the balance-granting mechanism in this embodiment.

[0049] Figure 3 This is an explanatory diagram illustrating the operation of the balance-improving mechanism in this embodiment.

[0050] Figure 4 This is an explanatory diagram illustrating the operation of the balance-improving mechanism in this embodiment.

[0051] Figure 5 This is an explanatory diagram illustrating the operation of the balance-improving mechanism in this embodiment.

[0052] Figure 6 This is an explanatory diagram showing the schematic structure of a balancing mechanism according to another embodiment of the present invention.

[0053] Figure 7 This is an explanatory diagram showing the schematic structure of the balancing mechanism according to another embodiment of the present invention. Detailed Implementation

[0054] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0055] In this example, the worktable device 1 is installed on a machine tool, such as a vertical or horizontal machining center. Figure 1 As shown, it consists of a worktable 2 on which the workpiece Wa is placed, a support mechanism 10 that supports the worktable 2 freely, a drive motor 20 that drives the support mechanism 10 to swing the worktable 2, a balancing mechanism 30 that applies a balancing load to the support mechanism 10 corresponding to the swing position of the worktable 2, and a control device 50 that controls the drive motor 20.

[0056] The aforementioned support mechanism 10 consists of a support platform 11 with a cross-section forming the shape of a letter U, a first rotating shaft 15 and a second rotating shaft 16 respectively connected to the outer sides of the upper ends of the first arm 13 and the second arm 14, a first support frame 17 that rotatably holds the first rotating shaft 15, and a second support frame 18 that rotatably supports the second rotating shaft 16. The support platform 11 consists of a bottom 12 that holds the workbench 2, and a first arm 13 and a second arm 14 that extend upward from both sides of the bottom 12.

[0057] The first rotating shaft 15 and the second rotating shaft 16 are coaxially arranged, and are configured such that when the bottom 12 of the support platform 11 is at its lowest position, the central axis is offset upward from the upper surface of the worktable 2. Furthermore, in Figure 1 In this configuration, the first rotating shaft 15 is configured to protrude from the first support frame 17 at its right and left ends, respectively. The upper end of the first arm 13 is connected to the right end, and the balance-improving mechanism 30 is connected to the left end. Furthermore, the first rotating shaft 15 is a hollow shaft with a through hole 15a formed at its center along its axis, and a through hole 13a is provided in the first arm 13, which is coaxially formed with the through hole 15a.

[0058] Furthermore, a rotor 21 is disposed on the outer periphery of the first rotating shaft 15, and an annular stator 22 is externally embedded in the first support frame 17. The rotor 21 and stator 22 constitute the drive motor 20, which drives the first rotating shaft 15 to rotate around its axial center. Moreover, due to the rotation of the first rotating shaft 15, the support platform 11 and the worktable 2 supported by the support platform 11 swing about the axes of the first rotating shaft 15 and the second rotating shaft 16. The unbalanced torque generated by the gravity of these swinging bodies acts on the first rotating shaft 15 and the drive motor 20. Furthermore, this unbalanced torque varies according to the swing angle of the support platform 11, reaching its maximum when the swing angle is ±90°. Additionally, the power supplied to the stator 22 is controlled by the control device 50.

[0059] Also Figure 2 As shown, the aforementioned balancing mechanism 30 includes: an eccentric plate 31, which is circular in shape and connected to the first rotating shaft 15 at an eccentric position from its center; a housing 32, which holds the outer periphery of the eccentric plate 31 via a bearing 33 composed of a plurality of cylindrical bodies (rotating bodies) disposed in a manner abutting against the outer peripheral surface of the eccentric plate 31; and a load-applying part 35, which applies a balancing load to the housing 32 in a direction intersecting the axis of the first rotating shaft 15. Furthermore, a through hole 31a, coaxially formed with the through hole 15a of the first rotating shaft 15, is provided on the eccentric plate 31.

[0060] The load-applying unit 35 is composed of a hydraulic cylinder 36 and a hydraulic unit 41 that supplies pressurized oil to the hydraulic cylinder 36. The cylinder 37 of the hydraulic cylinder 36 is supported by a support member 40, and the front end of the piston rod 38 is connected to the lower end of the housing 32 via a pin 39, with the axis of the pin 39 (which is parallel to the axis of the first rotation axis 15) as the center.

[0061] The aforementioned hydraulic unit 41 comprises an oil tank 43 for storing working oil and a pump 42 for pressurizing the working oil in the tank and supplying it to the hydraulic chamber 37a of the cylinder 37 via a supply pipe 44. Furthermore, a check valve 46 is installed in the supply pipe 44, and a reservoir 45 is connected to the supply pipe 44 between the check valve 46 and the pump 42. Additionally, a return pipe 47, communicating with the oil tank, branches off from the supply pipe 44 between the check valve 46 and the cylinder 37, and a safety valve 48 is installed in this return pipe 47.

[0062] Thus, pressurized oil at a certain pressure is supplied from the hydraulic unit 41 to the hydraulic cylinder 36, thereby applying a certain thrust to the housing 32 via the piston rod 38 of the hydraulic cylinder 36. Furthermore, the housing 32 transmits the thrust of the hydraulic cylinder 36 to the center position of the eccentric plate 31 via the bearing 33. Consequently, the eccentric plate 31 imparts a torque to the first rotating shaft 15 multiplied by the misalignment (offset) between the center of the first rotating shaft 15 and the center of the eccentric plate 31, multiplied by the thrust. This torque, as a balancing torque relative to the unbalanced torque, varies according to the rotation angle of the eccentric plate 31 centered on the first rotating shaft 15.

[0063] According to the worktable device 1 of this example with the above structure, under the control of the control device 50, the first rotating shaft 15 is rotated by the drive motor 20, and the support platform 11 and the worktable 2 supported on the support platform 11 can swing about the axis of the first rotating shaft 15.

[0064] Furthermore, when the worktable device 1 is installed on a machine tool such as a machining center, by swinging the worktable 2 in this way, the workpiece Wa placed on the worktable 2 can be machined to give the workpiece Wa a complex shape.

[0065] However, as described above, when the support platform 11 and the worktable 2 are oscillating, the unbalanced torque generated by the gravity of these oscillating bodies acts on the first rotating shaft 15 and the drive motor 20. However, through the balancing mechanism 30, a balancing torque is applied to the first rotating shaft 15 as a counterforce relative to the unbalanced torque. That is, when the first rotating shaft 15 rotates about its axis, the eccentric plate 31 also rotates about the axis of the first rotating shaft 15. Through the eccentric plate 1, the thrust of the hydraulic cylinder 36 acts as a balancing load on the first rotating shaft 15. This alleviates the load caused by the unbalanced torque on the drive motor 20. Furthermore, when the eccentric plate 31 rotates about the axis of the first rotating shaft 15, the housing 32 absorbs the misalignment of the eccentric plate 31 and moves up and down simultaneously according to its engagement relationship with the eccentric plate 31.

[0066] based on Figure 3 The above-mentioned balancing loads will be explained in more detail. Figure 3 The diagram shows the support platform 11 swinging 45° to the left. Furthermore, in... Figure 3 In this case, the right-hand rotation swing angle is set to positive. Therefore, the left-hand rotation swing angle becomes negative.

[0067] as Figure 3 As shown, when the weight of the swing body composed of the support platform 11, the worktable 2 and the workpiece Wa is set as W, and the distance between the center of gravity of the swing body and the center of the first rotating shaft 15 is set as R, the unbalanced torque Tu acting on the first rotating shaft 15 through the swing body is as follows.

[0068] Tu = R·W·sinθ

[0069] On the other hand, the distance between the center of the eccentric plate 31 and the center of the first rotating shaft 15 is set as r, and the thrust acting from the hydraulic cylinder 36 to the center of the eccentric plate 31 is set as F. The vertical component of the thrust F, F', is approximately the same as the thrust F. The balancing torque Tc acting on the first rotating shaft 15 is as follows.

[0070] Tc=r·F'·sinθ=r·F·sinθ

[0071] Thus, the balancing torque Tc, which serves as the counterforce to counteract the unbalanced torque Tu, should be:

[0072] Tc = Tu

[0073] Therefore, to become

[0074] R·W·sinθ=r·F·sinθ

[0075] Therefore, the thrust (balance load) F used to generate the balancing torque Tc, which is the reverse force relative to the unbalanced torque Tu, becomes

[0076] F = R·W / r

[0077] By the way, Figure 4 The diagram shows the support platform 11 swinging 90° to the left. Figure 5 The diagram shows the support platform 11 swinging 135° to the left, but when... Figure 3 When the support platform 11 shown swings 45° to the left, Figure 5 The unbalanced torque Tu and the balancing torque Tc are the same when the support platform 11 swings 135° to the left. Figure 4 When the support platform 11 shown swings 90° to the left, the unbalanced torque Tu and the balancing torque Tc reach their maximum values.

[0078] As described above, in the worktable device 1 of this example, the balancing torque Tc, which is the counterforce of the unbalanced torque Tu generated when the support table 11 and the worktable 2 swing, is applied to the first rotating shaft 15 through the balancing mechanism 30. Therefore, the load on the drive motor 20 caused by the unbalanced torque Tu is reduced.

[0079] Furthermore, in this example, the outer periphery of the eccentric plate 31 is held by the aforementioned housing 32 via the bearing 33. Therefore, the thrust F of the hydraulic cylinder 36 acts on the eccentric plate 31 in a dispersed state. Thus, a larger thrust F (balance load) can be applied to the eccentric plate 31 than before, and even under such a large balance load, the eccentric plate 31 is unlikely to be damaged.

[0080] Furthermore, as the first rotating shaft 15 rotates, the eccentric plate 31 also rotates around the axis of the first rotating shaft 15. However, the outer casing 32 only moves up and down with the rotation of the eccentric plate 31, without performing a circular motion that intersects the axis of the first rotating shaft 15. Therefore, by inserting the piping and wiring through the through hole 31a provided in the eccentric plate 31, the through hole 15a provided in the first rotating shaft 15, and the through hole 13a provided in the first arm 13, the piping and wiring can be guided onto the worktable 2. Thus, an automatic clamping mechanism and various sensors can be installed on the worktable 2.

[0081] The above describes one embodiment of the present invention, but the specific methods that the present invention can adopt are not limited to any of the above examples.

[0082] For example, in the worktable device 1 of the above example, the worktable 2 and the support platform 11 are configured to swing around the axes of the first rotation axis 15 and the second rotation axis 16 which are arranged parallel to the upper surface of the worktable 2. However, it is not limited to this. The worktable 2 and the support platform 11 may also be configured to swing around the axis of the rotation axis arranged in the direction that intersects the upper surface of the worktable 2.

[0083] In addition, in the example above, the bearing 33 supporting the eccentric plate 31 uses a cylindrical rotating body, but it is not limited to this. The bearing 33 can also be composed of multiple spherical rotating bodies or it can also be composed of a sliding bearing.

[0084] Furthermore, in the above example, the front end of the piston rod 38 is connected to the housing 32 in a structure that allows relative retraction via pin 39. However, this structure is not limited to this one. It can also be configured such that the front end of the piston rod 38 is fixedly mounted to the lower end of the housing 32, and the lower end of the cylinder 37 is connected to the support member 40 in a structure that allows relative retraction via pin 39. With this structure, the same effect as the worktable device 1 in the above example is achieved.

[0085] Additionally, the aforementioned load-bearing section 35 can, for example, be as follows: Figure 6 As shown, the bottom of its cylinder 37 is connected to the lower end of the aforementioned housing 32, and its piston rod 38 is appropriately supported by the support member 51 so that it can revolve via the pin 39. With this structure, the same effect as the worktable device 1 in the previous example is achieved.

[0086] Alternatively, in this case, the structure can be configured such that the bottom of the cylinder 37 and the lower end of the housing 32 are connected by a pin 39 to allow relative reversibility, and the front end of the piston rod 38 is fixedly mounted on the aforementioned support member 51.

[0087] Alternatively, it can be set to the following structure: Figure 7 The load-applying section 55 shown replaces the load-applying section 35 in the previous example. As... Figure 7 As shown, the load-applying unit 55 comprises a ball screw 56 rotatably disposed at the center of the axis and connected at one end to the lower end of the housing 32 via a rotary joint 57, a ball nut 59 screwed to the ball screw 56, a support member 60 supporting the ball nut 59, and a drive motor 61 connected to the other end of the ball screw 56 and causing the ball screw 56 to rotate. Furthermore, the rotary joint 57 is connected to the lower end of the housing 32 via a pin 58, centered on an axis parallel to the axis of the first rotation axis 15 (the axis of the pin 58), allowing it to revolve around this axis. Additionally, the drive motor 61 is controlled by the control device 50.

[0088] According to the load-applying unit 55, under the control of the control device 50, the drive motor 61 is driven. When the ball screw 56 rotates with the drive motor 61, it moves axially according to the engagement relationship with the ball nut 59. The ball screw 56 is then applied to the first rotating shaft 15 via the housing 32 and the eccentric plate 31 to provide a balanced torque corresponding to the thrust, thus achieving the same effect as the load-applying unit 35.

[0089] Moreover, in this case, by monitoring the load acting on the drive motor 20 and controlling the output of the drive motor 61 in such a way that the load becomes a load within a predetermined allowable range, the control device 50 can make a more rigorous balanced load acting on the first rotating shaft 15 to counteract the unbalanced torque acting on the first rotating shaft 15 and the drive motor 20. As a result, the load acting on the drive motor 20 due to the unbalanced torque can be more appropriately mitigated.

[0090] Although repeated, the description of the embodiments above is exemplary in all respects and not limiting. Suitable modifications and alterations will be apparent to those skilled in the art. The scope of the invention is set forth in the claims, not in the embodiments described above. Furthermore, variations from embodiments equivalent to those in the claims are included within the scope of the invention.

[0091] Explanation of reference numerals in the attached figures

[0092] 1 Workbench Device

[0093] 2 workbenches

[0094] 10 Support Mechanism

[0095] 11 support platform

[0096] 15 First Rotation Axis

[0097] 16 Second Rotation Axis

[0098] 17 First Support Frame

[0099] 18 Second Support Frame

[0100] 20 drive motors

[0101] 21 rotors

[0102] 22 stator

[0103] 30 Balance-Generating Mechanism

[0104] 31 Eccentric Plate

[0105] 32 casing

[0106] 33 bearing

[0107] 35 Load-bearing section

[0108] 36 hydraulic cylinders

[0109] 36a piston rod

[0110] 37 cylinders

[0111] 38 hydraulic units

[0112] 39 sales

[0113] 50 control devices

Claims

1. A worktable apparatus, characterized by, Possess: a table that places a workpiece; a support mechanism that has a rotation shaft, and supports the table swingably about the axis of the rotation shaft; a first drive motor that rotates the rotation shaft of the support mechanism to swing the table; a balance imparting mechanism that imparts a balance load corresponding to the swing position of the table to the rotation shaft; a control device that controls the first drive motor, the balance imparting mechanism is configured to possess: an eccentric plate that has a circular plate shape, and links the rotation shaft at a position eccentric from the center position; a housing that holds the outer peripheral portion of the eccentric plate via a bearing; a load imparting portion that imparts a balance load in a direction intersecting the axis of the rotation shaft to the housing.

2. The table device according to claim 1, wherein the rotation shaft of the support mechanism is arranged in parallel with the placement surface of the table.

3. The table device according to claim 1 or 2, wherein the load imparting portion is configured by a hydraulic cylinder whose cylinder portion is linked to the housing, and whose piston rod is supported by a support member, and the linking portion of the cylinder portion to the housing, or the linking portion of the piston rod to the support member is linked so as to be relatively returnable.

4. The table device according to claim 1 or 2, wherein the load imparting portion is configured by a hydraulic cylinder whose piston rod is linked to the housing, and whose cylinder is supported by a support member, and the linking portion of the piston rod to the housing, or the linking portion of the cylinder to the support member is linked so as to be relatively returnable.

5. The table device according to claim 1 or 2, wherein the load imparting portion is configured by a ball screw that is supported at the center of the axis so as to be rotatable, and whose one end is linked to the housing, a ball nut that is screwed with the ball screw, a support member that supports the ball nut, and a second drive motor that rotates the ball screw, the second drive motor is controlled by the control device, the linking portion of the housing to the ball screw is linked so as to be relatively returnable.

6. The table device according to claim 5, wherein the control device is configured to monitor the load acting on the first drive motor, and control the output of the second drive motor in such a manner that the load becomes a load within a predetermined allowable range.

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