Drive device and work machine

Abstract

To facilitate mounting and removal of a shock absorber of a drive device.SOLUTION: A drive device 500 for rotating a drive object M2 comprises: a motor part 1; a reduction gear 2 for reducing torque inputted from the motor part 1; and a shock absorber 3 for outputting torque inputted from the reduction gear 2 to the drive object M2 via elastic parts 33. At least a part of the shock absorber 3 is arranged on an opposite side to the motor part 1 and the reduction gear 2 across the drive object M2.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a drive device and a working machine. [Background technology]

[0002] Conventionally, there is known a series elastic actuator (SEA) that is attached to the joints of a work machine to perform precise rotational drive. In conventional SEAs, a spring unit is attached between the reducer and the joint for force control and shock absorption. This is because there is a risk of damage if an unexpected external force is applied from the output side to the motor or reducer.

[0003] As an example of the prior art related to the present invention, Patent Document 1 discloses an actuator in which a motor, a reducer, an elastic spring device, and a load are connected in this order. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-140300 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the performance of the SEA is limited by the spring characteristics (spring constant, etc.) of the elastic element installed. Therefore, it is necessary to change the elastic element depending on the situation. However, if the elastic element is placed between the reducer and the joint part, it is time-consuming and troublesome to attach and remove the elastic element.

[0006] SUMMARY OF THE PRESENT DISCLOSURE In view of the above circumstances, an object of the present invention is to facilitate the installation and removal of a shock absorber device in a drive system. [Means for solving the problem]

[0007] In order to achieve the above object, a drive device according to one aspect of the present invention rotates a driven object. The drive device includes a motor unit, a reducer, and a buffer device. The reducer reduces the speed of torque input from the motor unit. The buffer device outputs the torque input from the reducer from an output end to the driven object via an elastic unit. At least a portion of the buffer device is disposed on the opposite side of the driven object from the motor unit and the reducer.

[0008] In order to achieve the above object, a drive device according to another aspect of the present invention rotates a driven object. The drive device includes a motor unit, a reducer, and a shock absorber. The reducer reduces the speed of torque input from the motor unit. The shock absorber outputs the torque input from the reducer from an output end to the driven object via an elastic unit. The shock absorber is disposed inside a through hole disposed in the driven object.

[0009] In order to achieve the above object, a drive device according to another aspect of the present invention rotates a driven object. The drive device includes a motor unit, a shock absorber, and a first reducer. The shock absorber outputs the torque of the motor unit from an output end via an elastic unit. The first reducer reduces the torque input from the shock absorber. The shock absorber is disposed between the motor unit and the first reducer. The output end of the shock absorber is connected to the first reducer. The first output shaft of the first reducer is connected to the driven object.

[0010] In order to achieve the above object, a work machine according to one aspect of the present invention is configured to include any one of the drive devices described above.

[0011] Further features and advantages of the present invention will become apparent from the following embodiments. Effect of the Invention

[0012] According to the present invention, the shock absorber device for the drive unit can be easily attached and detached. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a left side view showing an example of an excavator according to an embodiment of the present invention; [Diagram 2] FIG. 1 is an external view showing an example of an SEA according to a first embodiment; [Diagram 3] Cross-section of the SEA seen from one side of the rotation axis [Figure 4] FIG. 1 is a conceptual diagram showing a first configuration example of an SEA according to a first embodiment; [Diagram 5] FIG. 13 is a conceptual diagram showing a second configuration example of the SEA according to the first embodiment; [Figure 6] FIG. 13 is a conceptual diagram showing a third configuration example of the SEA according to the first embodiment; [Figure 7] FIG. 13 is a conceptual diagram showing a fourth configuration example of the SEA according to the first embodiment; [Figure 8] FIG. 5 is a conceptual diagram showing a fifth configuration example of the SEA according to the first embodiment; [Figure 9] FIG. 13 is a conceptual diagram showing a sixth configuration example of the SEA according to the first embodiment; [Figure 10A] FIG. 7 is a conceptual diagram showing a seventh configuration example of an SEA according to a modification of the first embodiment; [Figure 10B] FIG. 13 is a conceptual diagram showing an eighth configuration example of an SEA according to a modification of the first embodiment; [Figure 11] FIG. 13 is a conceptual diagram showing a ninth configuration example of the SEA according to the second embodiment; [Figure 12] FIG. 17 is a conceptual diagram showing a tenth configuration example of the SEA according to the second embodiment. [Figure 13] FIG. 11 is a conceptual diagram showing an eleventh configuration example of an SEA according to a second embodiment. [Figure 14] FIG. 12 is a conceptual diagram showing a twelfth configuration example of the SEA according to the second embodiment. [Figure 15] FIG. 13 is a conceptual diagram showing a thirteenth configuration example of an SEA according to a modification of the second embodiment; [Figure 16] FIG. 14 is a conceptual diagram showing a fourteenth configuration example of the SEA according to the third embodiment. [Figure 17A] FIG. 13 is a cross-sectional view showing a configuration example of a shock absorber according to a fourth embodiment. [Figure 17B]FIG. 13 is a cross-sectional view showing another configuration example of the shock absorber according to the fourth embodiment. [Figure 18A] FIG. 13 is a schematic diagram showing a first arrangement example of a force control mechanism according to a modification of the fifth embodiment; [Figure 18B] FIG. 13 is a schematic diagram showing a second arrangement example of the force control mechanism according to the modified example of the fifth embodiment; [Figure 18C] FIG. 13 is a schematic diagram showing a third example of arrangement of the force control mechanism according to the modified example of the fifth embodiment; [Figure 19] FIG. 13 is a schematic diagram showing an example of the arrangement of a force control mechanism and a load measurement mechanism according to another modified example of the fifth embodiment; [Figure 20] A block diagram showing an example of reaction force control by a control unit. [Figure 21] Flowchart showing an example of control mode switching [Figure 22] FIG. 13 is a left side view showing a configuration example of a backhoe according to a sixth embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] <1. First embodiment> First, a schematic structure of an excavator 100 as an example of a work machine will be described with reference to Fig. 1. Fig. 1 is a left side view showing an example of an excavator 100 according to this embodiment.

[0016] <1-1. Mechanical configuration example> The excavator 100 includes a lower traveling body 200, an upper rotating body 300, a work machine 400, and an SEA (series elastic actuator) 500. The SEA 500 is an example of a "drive device" of the present invention, and includes a boom SEA 501, an arm SEA 502, and a bucket SEA 503. Hereinafter, these may be collectively referred to simply as "SEA 500." In other words, the excavator 100 includes the SEA 500.

[0017] The lower traveling body 200 is driven by power from a motor 302 built into the upper rotating body 300, causing the excavator 100 to travel. The lower traveling body 200 enables the excavator 100 to move forward and backward as the left and right traveling motors 202 drive the left and right crawlers 201, respectively. The upper rotating body 300 is mounted on the upper part of the lower traveling body 200, and is configured to be rotatable relative to the lower traveling body 200 via a swivel bearing (not shown).

[0018] An operation unit 301, a motor 302, a swivel base 303, a swivel motor 304, etc. are arranged on the upper swivel body 300. The upper swivel body 300 rotates by the driving force of the swivel motor 304 via a swivel bearing.

[0019] A driver's seat 3011 is disposed in the operation unit 301. A pair of work operation levers 3012 are disposed on the left and right sides of the driver's seat 3011. A pair of travel levers 3013 and an operation panel 3014 are disposed in front of the driver's seat 3011. A display unit and operation buttons are disposed on the operation panel 3014. The display unit displays images for informing the driver of the state of the excavator 100, etc. The driver sits in the driver's seat 3011 and operates the work operation levers 3012, the travel levers 3013, the operation panel 3014, etc. to control each actuator, etc., and perform travel, turning, work, etc.

[0020] The work machine 400 is attached to the upper rotating body 300 so as to be able to swing up and down. The work machine 400 is driven by power from a motor 302 and performs actual work such as excavating earth and sand. The work machine 400 includes a boom 401, an arm 402, and a bucket 403. The work machine 400 is able to perform the above-mentioned work by independently driving these components.

[0021] The base end of the boom 401 is supported to be swingable about a rotation axis R1 relative to the front part of the upper rotating body 300. The rotation axis R1 passes through the swing center of the connection part between the base end of the boom 401 and the front part of the upper rotating body 300, and extends in the left-right direction as seen by the operator. Hereinafter, this connection part is referred to as a first joint part 4051. The boom SEA 501 is disposed in the first joint part 4051. The boom SEA 501 drives the boom 401 to be swingable in the up-down direction relative to the front part of the upper rotating body 300.

[0022] The base end of the arm 402 is supported to be swingable about a rotation axis R2 relative to the tip of the boom 401. The rotation axis R2 passes through the swing center of the connection part between the base end of the arm 402 and the tip of the boom 401, and extends in the left-right direction as seen by the operator. Hereinafter, this connection part is referred to as a second joint part 4052. The arm SEA 502 is disposed in the second joint part 4052. The arm SEA 502 drives the arm 402 to be swingable in the up-down direction relative to the tip of the boom 401.

[0023] Bucket 403 is supported to be swingable about rotation axis R3 with respect to the tip of arm 402. Rotation axis R3 passes through the swing center of the connection part between bucket 403 and the tip of arm 402, and extends in the left-right direction as seen by the operator. Hereinafter, this connection part will be referred to as third joint part 4053. Bucket SEA 503 is disposed in third joint part 4053. Bucket SEA 503 drives bucket 403 to be swingable in the up-down direction with respect to the tip of arm 402.

[0024] In the following, the rotation axes R1, R2, and R3 may be collectively referred to as the "rotation axis R." Also, the first joint portion 4051 to the third joint portion 4053 may be collectively referred to simply as the "joint portion 405."

[0025] The excavator 100 further includes a storage unit 601 and a control unit 602. The storage unit 601 is a non-transient storage medium that retains memory even when the supply of power is stopped. The storage unit 601 stores information, programs, and the like used by the control unit 602 and the like. The control unit 602 controls each unit of the excavator 100 based on the information, programs, and the like stored in the storage unit 601, and for example receives an operation input from the operation unit 301 and issues a command to drive the motor 302, the SEA 500, and the like. The control unit 602 also feedback-controls the drive of the SEA 500 based on the detection result of the sensor 4, which will be described later, the reduction ratio of the reducer 2, and the like. The control of the working unit 400 of the excavator 100 and the drive control of the SEA 500 may be controlled by a single control unit 602, or may be controlled by separate control devices constituting the control unit 602.

[0026] <1-3. SEA500 configuration example> Next, configuration examples of the SEA 500 will be described with reference to Fig. 2 to Fig. 9. Fig. 2 is an external view showing an example of the SEA 500 according to the first embodiment. Fig. 3 is a cross-sectional view of the SEA 500 as viewed from one side of the rotation axis R. Figs. 4 to 9 are conceptual diagrams showing first to sixth configuration examples of the SEA 500 according to the first embodiment.

[0027] 2 to 9, the arm SEA502 is described as an example of the SEA500. Therefore, in FIG. 2 to FIG. 9 (and FIG. 10 to FIG. 16 described later), the tip of the boom 401 is given the reference symbol M1 as an example of the "first member" of the present invention, and the base end of the arm 402 is given the reference symbol M2 as an example of the "second member" of the present invention. The configurations of the other SEAs 500 (for example, the boom SEA501 and the bucket SEA503) are similar to that of the arm SEA502. In the case of the boom SEA501, the front part of the upper rotating body 300 corresponds to the "first member (M1)" of the present invention, and the base end of the boom 401 corresponds to the "second member (M2)" of the present invention. In the case of the bucket SEA503, the tip of the arm 402 corresponds to the "first member (M1)" of the present invention, and the bucket 403 corresponds to the "second member (M2)" of the present invention.

[0028] The SEA500 is disposed at a connection between a first member M1 and a second member M2 rotatably connected to the first member M1. The second member M2 is a drive target of the SEA500. The SEA500 is a drive device that rotates the second member M2 (i.e., the drive target), and outputs a torque to the second member M2 that rotates the second member M2 relative to the first member M1. The SEA500 includes a motor unit 1, a reducer 2, and a shock absorber 3. The motor unit 1, the reducer 2, the shock absorber 3, and the connection portion between the first member M1 and the second member M2 are aligned in the axial direction in which the rotation axis R extends. However, the order of the alignment is not limited to the order described above.

[0029] The motor unit 1 generates the above-mentioned torque and outputs it from the motor output shaft 11. The motor unit 1 is an electric motor in this embodiment, and is controlled by the control unit 602 and driven by receiving power supply from a battery (not shown).

[0030] The reducer 2 reduces the torque input from the motor unit 1. For example, the reducer 2 reduces the torque input to an input shaft 21 at a predetermined reduction ratio and outputs the torque from an output shaft 22. The reducer 2 is not particularly limited. For example, a parallel shaft reducer, a worm gear reducer, a bevel gear reducer, a planetary reducer, a strain wave gear reducer, or the like is used as the reducer 2.

[0031] The shock absorber 3 has an input end 31 to which torque is input, an output end 32 to which torque is output, an elastic portion 33, and a stopper 34. The input end 31 and the output end 32 are rotatable about a rotation axis R of the second member M2 (i.e., the driven object). The elastic portion 33 is disposed between the input end 31 and the output end 32 to connect them. In this embodiment, four elastic portions 331, 332, 333, and 334 are disposed. Hereinafter, these may be collectively referred to as "elastic portions 33."

[0032] The elastic portion 33 is disposed between the input end portion 31 and the output end portion 32 that are adjacent to each other in the circumferential direction based on the rotation axis R. That is, one circumferential end portion of the elastic portion 33 is fixed to the input end portion 31. The other circumferential end portion of the elastic portion 33 is fixed to the output end portion 32. The shock absorber 3 outputs the torque input from the reducer 2 from the output end portion 32 to the second member M2 (i.e., the driven object) via the elastic portion 33.

[0033] For example, as shown in FIG. 3, the elastic portion 33 has an elastic member 34 and a stopper 35.

[0034] The elastic member 34 has high elasticity and can expand and contract in the direction De from one of the input end 31 and the output end 32 to the other. In the following, the direction from the input end 31 to the output end 32 among the above-mentioned directions De is called "direction De1", and the direction from the output end 32 to the input end 31 is called "direction De2". The elastic member 34 is a spring coil in this embodiment. However, without being limited to this example, the elastic member 34 may be other than a spring coil, and may be an elastic body containing a resin material such as rubber or elastomer. Also, in this embodiment, the elastic member 34 is cylindrical and extends in the direction De. However, without being limited to this example, the elastic member 34 may be a solid columnar elastic body extending in the direction De.

[0035] The stopper 35 limits the contraction of the elastic member 34 in the direction De. In this embodiment, the stopper 35 includes a first stopper 351 and a second stopper 352.

[0036] The first stopper 351 is disposed at the input end 31. The first stopper 351 has a first base 3511 and a first restraining portion 3512. The first base 3511 is disposed on a surface of the input end 31 facing the output end 32 in the direction De, and spreads in a direction intersecting the direction De. The first restraining portion 3512 extends in the direction De2. That is, a base portion (an end portion on the direction De1 side) of the first restraining portion 3512 is connected to the first base 3511.

[0037] The tip end (end on the direction De2 side) of the first restraining portion 3512 faces a second base 3521 (described later) of the second stopper 352 in the direction De with a gap therebetween. This allows the first stopper 351 to restrict excessive contraction of the elastic member 34 in the direction De. This reduces the risk of deterioration and damage caused by the excessive contraction of the elastic member 34. This allows the life of the elastic member 34 to be extended.

[0038] Furthermore, the above-mentioned interval is larger than the limit value of the contraction length in the direction De of the elastic member 34, and in this embodiment, is larger than the sum of the intervals between adjacent turns in the direction De of the spring coil (corresponding to the above-mentioned limit value). This allows the first stopper 351 to prevent deterioration and damage caused by excessive contraction of the elastic member 34. For example, in this embodiment, the first stopper 351 can prevent adjacent turns in the direction De of the spring coil from abutting against each other and pressing against each other, that is, can prevent crushing in the direction De of the spring coil. This makes it possible to more reliably extend the life of the elastic member 34.

[0039] The second stopper 352 is disposed at the output end 32. The second stopper 352 has a second base 3521 and a second restricting portion 3522. The second base 3521 is disposed on a surface of the output end 32 facing the input end 31 in the direction De, and spreads in a direction intersecting the direction De. The second restricting portion 3522 extends in the direction De1. That is, a base portion (an end portion on the direction De2 side) of the second restricting portion 3522 is connected to the second base 3521.

[0040] The tip end (end on the direction De1 side) of the second restraining portion 3522 faces the first base 3511 of the first stopper 351 in the direction De with a gap therebetween. This allows the second stopper 352 to restrict excessive contraction of the elastic member 34 in the direction De. This reduces the risk of deterioration and damage caused by excessive contraction of the elastic member 34. This allows the life of the elastic member 34 to be extended.

[0041] Furthermore, the above-mentioned interval is larger than the limit value of the contraction length in the direction De of the elastic member 34, and in this embodiment, is larger than the sum of the intervals between adjacent turns in the direction De of the spring coil (corresponding to the above-mentioned limit value). This allows the second stopper 352 to prevent deterioration and damage caused by excessive contraction of the elastic member 34. For example, in this embodiment, the second stopper 352 can prevent adjacent turns in the direction De of the spring coil from abutting against each other and pressing against each other, that is, can prevent crushing in the direction De of the spring coil. This makes it possible to more reliably extend the life of the elastic member 34.

[0042] In this embodiment, the first restraining portion 3512 and the second restraining portion 3522 are disposed inside the elastic member 34. However, this is not limited to the example, and at least one of the first restraining portion 3512 and the second restraining portion 3522 may be disposed outside the elastic member 34 or may surround the elastic member 34.

[0043] In the present embodiment, the first restricting portion 3512 is cylindrical and extends in the direction De to surround the second restricting portion 3522, and is disposed outside the second restricting portion 3522. The second restricting portion 3522 is columnar and extends in the direction De. However, the present invention is not limited to this example, and the second restricting portion 3522 may be cylindrical and extends in the direction De to surround the first restricting portion 3512, and may be disposed outside the first restricting portion 3512. In this case, the first restricting portion 3512 extending in the direction De may be cylindrical or columnar.

[0044] Furthermore, the example of this embodiment does not exclude a configuration in which the stopper 35 does not have the first stopper 351 and the second stopper 352. In other words, either the first stopper 351 or the second stopper 352 may be omitted.

[0045] In response to the rotation of the output shaft 22 of the reducer 2, the input end 31 rotates about the rotation axis R. As shown in FIG. 3, the outer end of the input end 31 is connected to the outer end of the output end 32 via the elastic portion 33. Therefore, the elastic portion 33 expands and contracts in response to the magnitude of the rotation angle (i.e., phase) of the outer end of the input end 31. Furthermore, a torque acts on the outer end of the output end 32 from the outer end of the input end 31 via the elastic portion 33. This torque causes the output end 32 to rotate about the rotation axis R together with the second member M2 (i.e., the driven object) connected to the output end 32.

[0046] 3, when the input end 31 rotates clockwise on the page, the elastic portions 331 and 333 contract, and the outer end of the output end 32 is pushed by the elastic portions 331 and 333. In addition, the elastic portions 332 and 334 extend, and the outer end of the output end 32 is pulled by the elastic portions 332 and 334. As a result, a torque in the clockwise direction on the page acts on the outer end of the output end 32. Therefore, the second member M2 (i.e., the driven object) rotates together with the output end 32 in the clockwise direction on the page.

[0047] 3, when the input end 31 rotates counterclockwise on the page, the elastic portions 331 and 333 extend, and the outer end of the output end 32 is pulled by the elastic portions 331 and 333. The elastic portions 332 and 334 contract, and the outer end of the output end 32 is pushed by the elastic portions 332 and 334. As a result, a torque acts on the outer end of the output end 32 in the counterclockwise direction on the page. Therefore, the second member M2 (i.e., the driven object) rotates together with the output end 32 in the counterclockwise direction on the page.

[0048] Providing the shock absorber 3 in the SEA500 improves the backdrivability of the SEA500. Note that backdrivability refers to the property of an output node moving when an appropriate force is applied to the output node and transmitting the force to the input node, and generally the higher the reduction ratio, the lower the backdrivability becomes. In contrast, by installing the shock absorber 3, the elastic part 33 of the SEA500 absorbs sudden changes in torque and shocks caused by the action of external forces when they are transmitted from one of the input end 31 and the output end 32 to the other. Therefore, even if the reduction ratio of the reducer 2 is high, the SEA500 can still perform free and precise operation.

[0049] The connection portion between the first member M1 and the second member M2 has a through hole Mh extending in the axial direction (for example, the left-right direction) of the rotation shaft R. The through hole Mh includes a through hole disposed at the base end of the first member M1 and a through hole disposed at the tip end of the second member M2. In other words, the through hole Mh is a general term for the through hole disposed at the base end of the first member M1 and the through hole disposed at the tip end of the second member M2. The output shaft 22 of the reducer 2 is inserted through the through hole Mh. In the first embodiment, the output shaft 22 faces the inner surface of the through hole Mh in the radial direction with a gap therebetween, that is, the output shaft 22 does not contact the inner surface of the through hole Mh.

[0050] In the SEA500, at least a part of the shock absorber 3 is disposed on the opposite side of the motor unit 1 and the reducer 2 across the second member M2 (i.e., the driven object). In this embodiment, the entire shock absorber 3 is disposed on the opposite side of the motor unit 1 and the reducer 2 across the second member M2 (see Figs. 3 to 9). However, this is not limited to the example, and for example, a part of the shock absorber 3 may be disposed inside a through hole Mh disposed in the second member M2 (i.e., the driven object). In addition, the output shaft 22 of the reducer 2 is connected to the shock absorber 3, specifically to its input end 31, through a through hole Mh disposed in the second member M2 (i.e., the driven object). The output end 32 of the shock absorber 3 is connected to the second member M2 (i.e., the driven object).

[0051] In this way, for example, the shock absorber 3 can be easily attached and detached without removing the motor unit 1 and the reducer 2. Therefore, it is easy to replace the shock absorber 3 with one having different specifications, and to repair and inspect the shock absorber 3. Furthermore, when the shock absorber 3 is not required, for example, the shock absorber 3 can be removed and the output shaft 22 of the reducer 2 can be directly connected to the second member M2 for use.

[0052] Next, the SEA500 further includes a sensor 4 for detecting a relative phase (e.g., a rotation angle difference) between the input end 31 of the shock absorber 3 and the output end 32 of the shock absorber 3. The SEA500 detects the relative displacement between the input end 31 of the shock absorber 3 and the output end 32 of the shock absorber 3. This allows the load acting on the SEA500 to be calculated by determining the displacement of the elastic portion 33. Therefore, for example, the SEA500 can perform more accurate feedback control of the drive of the second member M2 based on the load. This improves the backdrivability of the SEA500.

[0053] For example, an encoder is used as the sensor 4. The encoder can detect a phase (for example, a rotation angle), a phase speed (for example, a rotation number), a relative phase (a rotation angle difference), and the like.

[0054] For example, as shown in FIG. 4, the sensor 4 detects the relative phase (e.g., rotation angle difference) of one of the input end 31 and the output end 32 with respect to the other. In this way, the load acting on the SEA 500 can be obtained based on the above-mentioned relative phase (e.g., rotation angle difference). Therefore, even if there is only one sensor 4, the SEA 500 can be sufficiently feedback-controlled based on the detection result. This reduces the number of parts, allowing the SEA 500 to be made smaller. Furthermore, the manufacturing efficiency and cost of the SEA 500 are reduced, improving its productivity.

[0055] 4, the sensor 4 is disposed on the axially outer side of the input end 31 and the output end 32 (i.e., on the right side of the paper in FIG. 4). However, the present invention is not limited to this example, and the sensor 4 may be disposed on the axially inner side of the input end 31 and the output end 32 (i.e., on the left side of the paper in FIG. 4, on the side of the motor unit 1 and the reducer 2) as shown in FIG. 7.

[0056] Alternatively, as shown in Figs. 5 to 9, the sensor 4 may include a first sensor 41 and a second sensor 42. For example, the first sensor 41 and the second sensor 42 are encoders attached at different locations. The first sensor 41 detects the relative phase (e.g., rotation angle difference) of the input end 31. The second sensor 42 detects the relative phase (e.g., rotation angle difference) of the output end 32. In this way, the relative phase (e.g., rotation angle difference) between the two is obtained based on each phase (e.g., rotation angle), and the load acting on the SEA 500 can be obtained from the relative phase (e.g., rotation angle difference). Therefore, feedback control of the SEA 500 can be performed based on the detection results of the first sensor 41 and the second sensor 42.

[0057] For example, in Figs. 5 and 9, the first sensor 41 is attached to the output side of the reducer 2 and detects the phase (for example, the rotation angle) of the output shaft 22 of the reducer 2 which rotates together with the input end 31. However, the present invention is not limited to this example. The first sensor 41 may be attached to the motor unit 1 as shown in Fig. 6 to detect the phase (for example, the rotation angle) of the motor output shaft 11. The first sensor 41 may also be disposed outside the motor unit 1 (left side of the paper in Fig. 6), or may be disposed between the motor unit 1 and the reducer 2 to detect the phase (for example, the rotation angle) of the motor output shaft 11 or the input shaft 21. In this case, the phase (for example, the rotation angle) of the input end 31 is obtained by determining the phase (for example, the rotation angle) of the output shaft 22 based on the detected phase (for example, the rotation angle) and the reduction ratio of the reducer 2. Alternatively, the first sensor 41 may be attached to the outer circumferential surface of the output shaft 22, or may be attached to the input end 31 as shown in Fig. 7. In the latter case, the first sensor 41 may be attached to the axially outer side of the input end 31 (the right side of the paper in FIG. 7) or to the axially inner side (the left side of the paper in FIG. 7).

[0058] 5 and 6, the second sensor 42 is attached to the output end 32. In this case, the second sensor 42 may be attached to the axially outer side of the output end 32 (the right side of the paper in FIG. 5 and FIG. 6) or may be attached to the axially inner side of the output end 32 (the left side of the paper in FIG. 5 and FIG. 6). However, this is not limited to the example. The second sensor 42 may be attached to the second member M2, for example, to detect the phase (for example, the rotation angle) of the second member M2 rotating together with the output end 32.

[0059] At least a part of the sensor 4 may be disposed in the through hole Mh of the second member M2 (i.e., the driven object). In this way, the volume occupied by at least a part of the sensor 4 outside the through hole Mh is reduced or eliminated. This reduces the size of the SEA 500, making the SEA 500 smaller and more compact.

[0060] For example, as shown in Fig. 7, a single sensor 4 that detects the relative phase (e.g., rotation angle difference) between the input end 31 and the output end 32 may be disposed in a through hole Mh of the connection portion between the first member M1 and the second member M2. In this case, the sensor 4 detects the phase (e.g., rotation angle) based on the phase (e.g., rotation angle) of the input end 31 and the phase (e.g., rotation angle) of the output end 32 or the second member M2. In Fig. 7, the entire single sensor 4 is accommodated in the through hole Mh. However, this is not limited to the example, and a part of the single sensor 4 may be accommodated in the through hole Mh.

[0061] Alternatively, as shown in Fig. 8 and Fig. 9, at least one of the first sensor 41 and the second sensor 42 may be disposed in the through hole Mh of the connection portion of the first member M1 and the second member M2. For example, in Fig. 8, the first sensor 41 is disposed outside the through hole Mh, while the second sensor 42 is disposed on the inner circumferential surface of the second member M2 in the through hole Mh. Alternatively, the second sensor 42 may be disposed outside the through hole Mh, for example, as shown in Fig. 5, while the first sensor 41 may be disposed on the output side (output shaft 22, etc.) of the reducer 2 in the through hole Mh, as shown in Fig. 9. Also, in Fig. 9, both the first sensor 41 and the second sensor 42 are disposed in the through hole Mh.

[0062] <1-4. Modification of the first embodiment> Next, a modified example of the first embodiment will be described with reference to Fig. 10A and Fig. 10B. Fig. 10A is a conceptual diagram showing a seventh configuration example of an SEA according to a modified example of the first embodiment. Fig. 10B is a conceptual diagram showing an eighth configuration example of an SEA according to a modified example of the first embodiment.

[0063] In a modified example of the first embodiment, the shock absorber 3 is disposed inside a through hole Mh disposed in the second member M2 (i.e., the driven object). The output shaft 22 of the reducer 2 is connected to the input end 31 of the shock absorber 3 through the through hole Mh. The output end 32 of the shock absorber 3 is connected to the second member M2. For example, in Figs. 10A and 10B, the entire shock absorber 3 is disposed inside the through hole Mh. However, the examples of Figs. 10A and 10B do not exclude a configuration in which the entire shock absorber 3 is not disposed inside the through hole Mh. For example, a part of the shock absorber 3 may be disposed outside the through hole Mh.

[0064] In this way, for example, the shock absorber 3 can be easily attached and detached without removing the motor unit 1 and the reducer 2. This makes it easy to replace the shock absorber 3 with one having different specifications, and to repair and inspect the shock absorber 3. Furthermore, when the shock absorber 3 is not required, for example, the shock absorber 3 can be removed and the output shaft 22 of the reducer 2 can be directly connected to the second member M2 for use.

[0065] Furthermore, by disposing at least a part of the shock absorber 3 inside the through hole Mh, the size of the SEA 500 in the axial direction along which the central axis of the through hole Mh extends (for example, the left-right direction) can be further reduced, thereby making it possible to make the SEA 500 smaller and more compact.

[0066] Preferably, at least a part of the sensor 4 is disposed in the through hole Mh. More preferably, the entire sensor 4 is disposed in the through hole Mh. For example, in FIG. 10A, a single sensor 4 that detects the relative phase (e.g., rotation angle difference) between the input end 31 and the output end 32 is disposed in its entirety in the through hole Mh. Also, in FIG. 10B, the entire first sensor 41 that detects the phase (e.g., rotation angle) of the output shaft 22 (i.e., the phase (e.g., rotation angle) of the input end 31) and the entire second sensor 42 that detects the phase (e.g., rotation angle) of the output end 32 are disposed in the through hole Mh. Note that, although the second sensor 42 is disposed at the output end 32 in FIG. 10B, the second sensor 42 is not limited to this example, and may be disposed on the inner circumferential surface of the second member M2 to detect the phase (e.g., rotation angle) of the second member M2.

[0067] This further reduces the size of the SEA 500 in the axial direction (e.g., left-right direction), thereby making the SEA 500 even smaller and more compact.

[0068] However, the above examples do not exclude a configuration in which the entire sensor 4 is disposed outside the through-hole Mh in the modified example illustrated in FIGS. 10A and 10B.

[0069] <2. Second embodiment> Next, the second embodiment will be described with reference to Fig. 11 to Fig. 14. Fig. 11 to Fig. 14 are conceptual diagrams showing ninth to twelfth configuration examples of an SEA according to the second embodiment, respectively. Configurations different from the first embodiment and its modifications will be described below. In the second embodiment, components similar to those in the first embodiment and its modifications are given the same reference numerals, and their description may be omitted. In addition, the second embodiment can be arbitrarily combined with the first embodiment and its modifications as long as no particular contradiction occurs.

[0070] In the second embodiment, the shock absorber 3 is disposed between the motor unit 1 and the reducer 2. The shock absorber 3 outputs the torque of the motor unit 1 from an output end 32 via an elastic portion 33. The output end 32 of the shock absorber 3 is connected to the reducer 2, specifically, to its input shaft 21. The reducer 2 reduces the torque input from the shock absorber 3. The output shaft 22 of the reducer 2 is connected to the second member M2 (i.e., the driven object). For example, in Figs. 11 to 14, the output shaft 22 is inserted through the through hole Mh and contacts the inner side surface of the second member M2 (through hole Mh).

[0071] In this way, the shock absorber 3 can be adopted with specifications corresponding to the torque output by the motor unit 1. For example, a shock absorber 3 that is smaller, more compact, and lighter can be used compared to a configuration in which the shock absorber 3 is disposed between the reducer 2 and the second member M2. By making the shock absorber 3 small, compact, and light, it becomes easier to carry the shock absorber 3 when attaching and detaching the shock absorber 3 during assembly, repair, inspection, and the like of the SEA500. Furthermore, the shock absorber 3 can be attached and detached by removing only the motor unit 1 out of the motor unit 1 and the reducer 2. In other words, the shock absorber 3 can be attached and detached without removing both the motor unit 1 and the reducer 2. Therefore, the shock absorber 3 can be easily attached and detached. Furthermore, the degree of freedom in selecting the shock absorber 3 increases, so that shock absorbers 3 of various configurations and types can be used according to the situation.

[0072] In FIG. 11, a single sensor 4 for detecting the relative phase (e.g., rotation angle difference) between the input end 31 and the output end 32 is disposed between the reducer 2 and the shock absorber 3. However, the present invention is not limited to this example, and the single sensor 4 may be disposed between the motor unit 1 and the shock absorber 3. Alternatively, as shown in FIG. 12, the single sensor 4 may be disposed on the opposite side of the second member M2 from the motor unit 1 and the reducer 2, and detect the phase (e.g., rotation angle) difference between the first member M1 and the second member M2. In this way, it becomes easy to accurately feedback-control the drive of the second member M2 based on the relative phase (e.g., rotation angle difference). This improves the backdrivability of the SEA 500.

[0073] 13 and 14, the sensor 4 may include a third sensor 43 and a fourth sensor 44. The third sensor 43 detects the phase (e.g., rotation angle) of the motor output shaft 11 of the motor unit 1. The fourth sensor 44 detects the phase (e.g., rotation angle) of either the input shaft 21 or the output shaft 22 of the reducer 2. In this way, the relative phase (e.g., rotation angle difference) between the two is obtained based on the detection results of the third sensor 43 and the fourth sensor 44, and the load acting on the SEA 500 is obtained. Therefore, feedback control of the SEA 500 can be performed based on the detection results of the third sensor 43 and the fourth sensor 44.

[0074] For example, the third sensor 43 may be disposed between the motor unit 1 and the shock absorber 3 as shown in FIG. 13, or may be disposed on the axial opposite side of the motor unit 1 from the shock absorber 3 as shown in FIG.

[0075] The fourth sensor 44 may be disposed between the shock absorber 3 and the reducer 2 as shown in Fig. 13, or may be disposed on the axial side of the reducer 2 opposite to the shock absorber 3 as shown in Fig. 14. In Fig. 14, the fourth sensor 44 can be said to be disposed at the tip of the output shaft 22, or to be disposed on the opposite side to the reducer 2 across the connection between the first member M1 and the second member M2. In Fig. 14, the fourth sensor 44 may detect the phase (e.g., rotation angle) of the second member M2, and the detection result may be the phase (e.g., rotation angle) of the output shaft 22.

[0076] <2-1. Modification of the second embodiment> Next, a modified example of the second embodiment will be described with reference to Fig. 15. Fig. 15 is a conceptual diagram showing a thirteenth configuration example of an SEA according to the modified example of the second embodiment.

[0077] In the modified example of the second embodiment, the sensor 4 includes a fifth sensor 45, a sixth sensor 46, a first rotation transmission member 471, and a second rotation transmission member 472. The first rotation transmission member 471 and the second rotation transmission member 472 are belt-shaped members.

[0078] The first rotation transmission member 471 transmits the rotation of the motor output shaft 11 of the motor unit 1 radially outward from between the motor unit 1 and the shock absorber 3. The first rotation transmission member 471 is hung between the motor output shaft 11 of the motor unit 1 and the fifth sensor 45. In Fig. 15, the first rotation transmission member 471 is hung on the motor output shaft 11 between the motor unit 1 and the shock absorber 3. However, this is not limiting, and the first rotation transmission member 471 may be hung on the motor output shaft 11 on the axially opposite side of the motor unit 1 to the shock absorber 3.

[0079] The second rotation transmission member 472 transmits rotation of at least one of the output end portion 32 of the shock absorber 3, the input shaft 21 of the reducer 2, and the output shaft 22 of the reducer 2 radially outward from between the shock absorber 3 and the second member M2 (i.e., the driven object). In Fig. 15, the second rotation transmission member 472 is hung between at least one of the output end portion 32 and the input shaft 21 and the sixth sensor 46. However, this is not limiting, and the second rotation transmission member 472 may be hung around the output shaft 22 of the reducer 2.

[0080] The fifth sensor 45 detects the phase (eg, rotation angle) of the first rotation transmission member 471, and thereby detects the phase (eg, rotation angle) of the motor output shaft 11 (that is, the phase (eg, rotation angle) of the input end 31).

[0081] The sixth sensor 46 detects the phase (for example, rotation angle) of the second rotation transmission member 472, and thereby detects the phase (for example, rotation angle) of at least one of the output end portion 32, the input shaft 21, and the output shaft 22.

[0082] In this way, the phase (e.g., rotation angle) of the input end 31 and the phase (e.g., rotation angle) of the output end 32 of the shock absorber 3 are detected radially outward from the space between the motor unit 1 and the reducer 2. Therefore, the relative phase (e.g., rotation angle difference) between the input end 31 and the output end 32 (in other words, the load acting on the SEA 500) can be obtained without disposing a sensor for detecting the phase (e.g., rotation angle) between the motor unit 1 and the second member M2.

[0083] <3. Third embodiment> Next, the third embodiment will be described with reference to FIG. 16. FIG. 16 is a conceptual diagram showing a fourteenth configuration example of an SEA according to the third embodiment. Below, a configuration different from the first to second embodiments and their modified examples will be described. In the third embodiment, components similar to those in the first to second embodiments and their modified examples are given the same reference numerals, and their description may be omitted. In addition, the third embodiment can be arbitrarily combined with the first to second embodiments and their modified examples, as long as no particular contradiction occurs.

[0084] In the third embodiment, the SEA 500 includes two reducers 2 and 5. The shock absorber 3 is disposed between the two reducers 2 and 5. For example, the reducer 2 is disposed between the shock absorber 3 and the second member M2. The reducer 5 is disposed between the motor unit 1 and the shock absorber 3, and reduces the torque input from the motor unit 1. In detail, the reducer 5 reduces the torque input to the input shaft 51 at a predetermined reduction ratio and outputs the torque from the output shaft 52. Preferably, the reduction ratio of the reducer 5 is higher than that of the reducer 2. However, this example does not exclude a configuration in which the reduction ratio of the reducer 5 is equal to or lower than that of the reducer 2.

[0085] The input shaft 51 of the reducer 5 is connected to the motor output shaft 11 of the motor unit 1. The output shaft 52 of the reducer 5 is connected to the shock absorber 3, specifically to its input end 31. In this way, the reducers 2.5 are arranged in the front and rear stages of the shock absorber 3, respectively. In other words, the shock absorber 3 is arranged between the two reducers 2, 5. For example, the backdrivability of the reducers 2, 5 decreases according to the reduction ratio. Therefore, by making the reduction ratio of the reducer 5 in the front stage higher than that of the reducer 2 in the rear stage, it becomes easy to reduce the torque transmitted from the motor unit 1 to the second member M2 at a high reduction ratio without increasing the size of the shock absorber 3. In other words, both a high reduction ratio and a small size of the shock absorber 3 can be realized.

[0086] In the SEA 500 of the third embodiment, the sensor 4 may be a single sensor that detects the relative phase (e.g., the rotation angle difference) between the input end 31 and the output end 32 as shown in Fig. 16. Alternatively, the sensor 4 may have a sensor that detects the phase (e.g., the rotation angle) of the input end 31 and a sensor that detects the phase (e.g., the rotation angle) of the output end 32. The arrangement of the sensor 4 is not particularly limited, and may be any of the arrangements illustrated in Figs. 4 to 16, for example.

[0087] <4. Fourth embodiment> Next, a fourth embodiment will be described with reference to Fig. 17A and Fig. 17B. Fig. 17A is a cross-sectional view showing a configuration example of the shock absorber 3 according to the fourth embodiment. Fig. 17B is a cross-sectional view showing another configuration example of the shock absorber 3 according to the fourth embodiment. The cross section of the elastic portion 33 in Fig. 17A and Fig. 17B corresponds to the portion XVII surrounded by the dashed line in Fig. 3.

[0088] The following describes the fourth embodiment in terms of its configuration, which differs from the first to third embodiments and their modified examples. In the fourth embodiment, the same components as those in the first to third embodiments and their modified examples are given the same reference numerals, and the description thereof may be omitted. The fourth embodiment can be arbitrarily combined with the first to third embodiments and their modified examples, as long as no particular contradiction occurs.

[0089] In the fourth embodiment, the SEA 500 further includes a displacement sensor 6. The displacement sensor 6 is a sensor for detecting the amount of expansion and contraction (displacement) of the elastic member 34 of the elastic portion 33 in the direction De, and outputs the detection result to the control unit 602. For example, as shown in Figures 17A and 17B, the displacement sensor 6 is disposed inside the cylindrical elastic member 34, the cylindrical first restraining portion 3512, and the cylindrical second restraining portion 3522, on either the surface of the first base 3511 facing the direction De2 or the surface of the second base 3521 facing the direction De1.

[0090] In this embodiment, the displacement sensor 6 is a laser displacement meter and is disposed on the first base 3511 side. The displacement sensor 6 detects a change in the distance (displacement) between the displacement sensor 6 and the surface of the first base 3511 on the direction De2 side based on a laser light L1 emitted from the laser displacement meter and its reflected light L2. However, the example of this embodiment does not exclude a configuration in which the displacement sensor 6 is not a laser displacement meter. The displacement sensor 6 may be any type of displacement meter as long as it can detect the amount of expansion and contraction (displacement) of the elastic member 34 in the direction De, and may be, for example, either a contact type displacement meter such as a linear encoder or a non-contact type displacement meter such as an ultrasonic displacement meter.

[0091] The control unit 602 calculates the phase (e.g., rotation angle) and phase speed (e.g., rotation speed) between the input end 31 and the output end 32 connected via the elastic portion 33 based on the detection result of the displacement sensor 6. The control unit 602 may also calculate the relative phase (rotation angle difference) of one of the input end 31 and the output end 32 with respect to the other. Furthermore, the control unit 602 calculates the load acting on the SEA 500 based on the above-mentioned calculation result, and feedback controls the SEA 500.

[0092] The displacement sensor 6 can accurately detect a change (displacement) in the distance between the input end 31 and the output end 32 via the elastic portion 33. Therefore, the control unit 602 can more accurately calculate the above-mentioned phase (e.g., rotation angle), phase velocity (e.g., number of rotations), and relative phase (rotation angle difference), etc., compared to the case where the detection result of the sensor 4, such as an encoder, is used. Therefore, by using the detection result of the displacement sensor 6, the control unit 602 can perform feedback control of the SEA 500 more accurately.

[0093] By using the displacement sensor 6 as described above, the detection accuracy of the displacement is improved, and it is possible to detect minute displacements, for example, in the order of μm. Therefore, the displacement sensor 6 may detect minute vibration components (for example, in the order of μm) in the direction De of the elastic member 34. The minute vibration components are reciprocating minute displacements, and may act as detection noise of the displacement sensor 6 and may adversely affect the feedback control of the SEA 500.

[0094] Therefore, the control unit 602 preferably includes a signal smoothing unit 603. The signal smoothing unit 603 is a filter that smoothes the output signal indicating the detection result of the displacement sensor 6. For the smoothing process, a method such as the least squares method, moving average, moving median, linear regression, or quadratic regression can be adopted. The control unit 602 accurately calculates the displacement of the elastic member 34, the above-mentioned phase (e.g., rotation angle), phase velocity (e.g., rotation number), and relative phase (rotation angle difference), etc., based on the smoothed output signal of the displacement sensor 6. Therefore, the control unit 602 can more accurately feedback control the SEA 500 while suppressing or preventing the influence of minute vibration components in the direction De of the elastic member 34. However, this example does not exclude a configuration in which the control unit 602 does not include the signal smoothing unit 603.

[0095] Next, the displacement sensor 6 is disposed in at least one elastic portion 33 of the shock absorber 3, and preferably in all elastic portions 33. By disposing the displacement sensors 6 in more elastic portions 33, the control portion 602 can more accurately calculate the above-mentioned phase, phase velocity, and relative phase, and can perform feedback control of the SEA 500 with higher accuracy.

[0096] Furthermore, in the fourth embodiment, the arrangement of the displacement sensors 6 can reduce or eliminate the arrangement of the sensors 4 (e.g., encoders). This allows the SEA 500 to be made more compact. However, this example does not exclude a configuration in which the arrangement of the sensors 4 is not omitted. In other words, the SEA 500 may be provided with the displacement sensors 6 and sensors 4 (e.g., encoders), or only the displacement sensors 6.

[0097] In the fourth embodiment, the wiring 61 of the displacement sensor 6 is led from the inside of the elastic member 34 and the stopper 35 to the outside thereof, and is connected to an external control unit 602 or the like.

[0098] For example, as shown in FIG. 17A, the wiring 61 is led out through the first passage 3513 of the first stopper 351, the second passage 3523 of the second stopper 352, and the passage 341 of the elastic member .

[0099] The first passage 3513 is disposed in the first restraining portion 3512 of the first stopper 351, and extends in a direction intersecting the direction De. One end of the first passage 3513 opens to the inner surface of the first restraining portion 3512, and the other end opens to the outer surface of the first restraining portion 3512.

[0100] The second passage 3523 is disposed in the second restraining portion 3522 of the second stopper 352, and extends in a direction intersecting the direction De. One end of the second passage 3523 opens to the inner surface of the second restraining portion 3522, and the other end opens to the outer surface of the second restraining portion 3522.

[0101] The passage 341 is disposed in the elastic member 34 and connects the inside and outside of the elastic member 34. In this embodiment, the passage 341 is a gap between adjacent turns of the spring coil (i.e., the elastic member 34) in the direction De. The expansion and contraction of the spring coil is limited by the stopper 35 to such an extent that the above-mentioned gap is not closed and the wiring 61 is not always compressed by the turns. If the elastic member 34 is not a spring coil but is, for example, cylindrical, the passage 341 extending in a direction intersecting the direction De is disposed in the elastic member 34 and connects the inside and outside of the elastic member 34.

[0102] 17A, regardless of the displacement in the direction De of the second restraining portion 3522 accompanying the expansion and contraction of the elastic member 34, one end of the second passage 3523 is always connected to the other end of the first passage 2513 and to the inner end of the passage 341. For example, preferably, in the direction De, the width h2 of the second passage 3523 is wider than the width h1 of the first passage 3513 and the width h3 of the passage 341. However, this example does not exclude a configuration where h2≦h1 or h2≦h3, as long as the second passage 3523 is always connected to the first passage 3513 and the passage 341 so that the wiring 61 can be inserted therethrough.

[0103] 17B , the wiring 61 may be drawn from the inside of the elastic member 34 and the stopper 35 to the outside of them through a groove 353 arranged on a surface of the base 3521 of the second stopper 352 facing the direction De1 of the base 3521. The groove 353 is recessed in the direction De2 and extends in a direction intersecting the direction De. One end of the groove 353 is connected to a space (where the displacement sensor 6 is arranged) on the inside of the elastic member 34 and the stopper 35. The other end of the groove 353 is connected to a space on the outside of the elastic member 34 and the stopper 35.

[0104] 17A and 17B, the wiring 61 is drawn to the outside without being compressed due to expansion and contraction (displacement) in the direction De of the elastic member 34. That is, it is possible to avoid the risk of the wiring 61 being broken due to the above-mentioned compression.

[0105] In the fourth embodiment, the displacement sensor 6 is connected to an external control unit 602 or the like by wire 61. However, the present invention is not limited to this example, and the displacement sensor 6 may wirelessly communicate with the external control unit 602 or the like. In the latter case, the wire 61 is omitted.

[0106] <5. Fifth embodiment> Next, a fifth embodiment will be described. In the fifth embodiment, a configuration different from the first to fourth embodiments and their modified examples will be described. In the fifth embodiment, the same components as those in the first to fourth embodiments and their modified examples will be given the same reference numerals, and the description thereof may be omitted. In addition, the fifth embodiment can be arbitrarily combined with the first to fourth embodiments and their modified examples, as long as no particular contradiction occurs.

[0107] In a work machine such as the excavator 100, materials may be hoisted using a hoisting tool 404 (see FIG. 1) arranged near the tip of the bucket 403 or the third joint portion 4053. In addition, other attachments may be attached in place of the bucket 403 to hold the material, for example, by aligning it with a specific surface of a plate-shaped material. Conventionally, these operations have been performed by visual confirmation by the operator or an assistant worker.

[0108] However, performing the above-mentioned tasks by visual confirmation requires skilled operation or cooperation, which is prone to operational errors. In addition, in situations where it is difficult to visually confirm, it is difficult to perform the tasks with appropriate movements and force. In addition, when a work assistant assists, the above-mentioned tasks require multiple people.

[0109] In view of the above circumstances, the fifth embodiment has an object to provide a work machine capable of performing actual work at the tip of the work implement 400 with appropriate operation and driving force.

[0110] In the fifth embodiment, the excavator 100 is capable of controlling the reaction force of the working machine 400. For example, when the tip of the working machine 400 comes into contact with an object such as a work target, a reaction force acts on the tip from the object. In the reaction force control, first, the excavator 100 can detect that the tip of the working machine 400 has come into contact with an object by detecting the occurrence of a reaction force Fo acting on the tip of the working machine 400. This allows the excavator 100 to prevent the contacted object, the working machine 400, etc. from being damaged by, for example, stopping the operation of the working machine 400 or moving the working machine 400 away from the contacted object when contact is detected.

[0111] In addition, the reaction force Fo (magnitude and direction) can be estimated, and a target reaction force can be set in accordance with the object, etc., and the reaction force Fo can also be adjusted. This makes it possible to prevent the work machine 400 from being damaged by an excessive load when the work machine 400 comes into contact with the object.

[0112] The reaction force control can be switched ON / OFF by, for example, an operational input from the operation unit 301 .

[0113] For example, a force control mechanism 510 or a load measurement mechanism 520 is disposed in at least one of the connection parts of the backhoe 100. The connection parts of the work machine 100 include a part 406 (see FIG. 1 ) where the upper rotating body 300 is rotatably connected to the lower traveling body 200, and a joint part 405 of the work implement 400. The joint part 405 of the work implement 400 includes a first joint part 4051 between the base end part of the boom 401 and the front part of the upper rotating body 300, a second joint part 4052 between the base end part of the arm 402 and the tip part of the boom 401, a third joint part 4053 between the bucket 403 and the tip part of the arm 402, and the like.

[0114] The force control mechanism 510 has at least a driving function, and preferably further has a load measuring function. The force control mechanism 510 drives the joint part 405 under the control of the control unit 602 by the driving function, and measures the load acting on the joint part 405 by the load measuring function and outputs it to the control unit 602.

[0115] The SEA 500 can be used as the force control mechanism 510. The direction and magnitude of the load applied to the SEA 500 when performing work is calculated by the control unit 602 based on the detection result of the sensor 4, the detection result of the displacement sensor 6 of the third embodiment, and the like. For example, the direction and magnitude of the load applied to the SEA 500 can be calculated based on the displacement (displacement direction, displacement amount based on the unloaded state) of the elastic member 34 at each point in time and the elastic coefficient of the elastic member 34, and the like, in other words, the elastic force of the elastic member 34 at each point in time. However, this example does not exclude a configuration in which the force control mechanism 510 is not the SEA 500.

[0116] The load measuring mechanism 520 detects the magnitude and direction of the load acting on the joint part 405, and outputs the detected magnitude and direction to the control unit 602. The load measuring mechanism 520 is, for example, a force sensor, and is attached to the joint part 405.

[0117] In the fifth embodiment, when the work machine 400 is operated, the control unit 602 estimates the magnitude and direction of a reaction force Fo acting on the tip of the work machine 400 based on a detection result of at least a load (magnitude and direction) acting on the joint portion 405. The magnitude and direction of the reaction force Fo can be calculated by solving forward kinematics of robotics based on the torque (load) acting on the joint portion 405 and the attitude angle (for example, rotation angle) of the joint portion 405. The control unit 602 controls the driving of the force control mechanism 510 or actuator of each joint portion 405 of the excavator 100 based on the estimated result of the reaction force Fo and the target reaction force Fd (magnitude and direction), and adjusts the actual reaction force Fo.

[0118] The reaction force Fo is a reactive force that the tip of the work machine 400 receives from the work target during work. The target reaction force Fd is an ideal reaction force Fo that acts on the tip of the work machine 400 when the work machine 400 is driven with an appropriate operation and driving force. The target reaction force Fd is set, for example, based on an operation input received by the operation unit 301, and stored in the memory unit 601.

[0119] The magnitudes of the reaction force Fo and the target reaction force Fd are expressed by their absolute values. The directions of the reaction force Fo and the target reaction force Fd are expressed by their positive and negative values. For example, if the values ​​of the reaction force Fo and the target reaction force Fd are both positive, they are in the same predetermined direction. If both are negative, they are in the opposite direction to the positive direction described above. On the other hand, if the positive and negative values ​​are different, the direction of one of the two is the same as the opposite direction of the other.

[0120] Preferably, if the magnitude of the estimated reaction force Fo (corresponding to the absolute value of the amplification value Pg in FIG. 20 described later) is less than a predetermined value (corresponding to the absolute values ​​of the predetermined values ​​Pu, Pd in ​​FIG. 20), the control unit 602 corrects the drive of the work machine 400 and the force control mechanism 510 (e.g., SEA 500) based on the estimated reaction force Fo. On the other hand, if the magnitude of the estimated reaction force Fo (corresponding to the absolute value of the amplification value Pg in FIG. 20 described later) is equal to or greater than a predetermined value (corresponding to the absolute values ​​of the predetermined values ​​Pu, Pd in ​​FIG. 20), the control unit 602 corrects the drive of the work machine 400 and the force control mechanism 510 (e.g., SEA 500) based on the predetermined value.

[0121] In addition, the control unit 602 corrects the driving direction and driving amount (in other words, the movement amount) of the tip of the work machine 400 when the work machine 400 is operated based on the estimated reaction force Fo (magnitude and direction) and the target reaction force Fd (magnitude and direction).

[0122] By the above-mentioned control, the excavator 100 can make the working machine 400 work with appropriate operation and driving force. For example, the excavator 100 can make the actual reaction force Fo approach and preferably match the target reaction force Fd, or make the working machine 400 work while keeping the reaction force Fo constant. Therefore, the excavator 100 can perform actual work at the tip of the working machine 400, such as hoisting materials and holding materials with an alternative attachment, with appropriate operation and driving force without requiring assistance such as visual confirmation by the operator and the assistant worker. In addition, it is possible to prevent the working machine 400 and / or the work target from being damaged by the operation of the working machine 400 (the tip of the working machine 400).

[0123] <5-1. Example of arrangement of the force control mechanism 510 and the load measurement mechanism 520> In the backhoe 100 , a force control mechanism 510 is attached to at least one joint portion 405 of the work machine 400 .

[0124] <5-1-1.Example> For example, a force control mechanism 510 having a driving function and a load measuring function is attached to all of the joints 405 of the working machine 400 (see FIG. 1). In this way, the control unit 602 can detect the load at all of the joints 405 and drive all of the joints 405 with appropriate operation and driving force. Therefore, the working machine 400 can achieve flexible operation.

[0125] <5-1-2. Modifications> Alternatively, the force control mechanism 510 may be attached to a part of the joints 405 of the working machine 400. FIG. 18A is a schematic diagram showing a first arrangement example of the force control mechanism 510 according to a modification of the fifth embodiment. FIG. 18B is a schematic diagram showing a second arrangement example of the force control mechanism 510 according to a modification of the fifth embodiment. FIG. 18C is a schematic diagram showing a third arrangement example of the force control mechanism 510 according to a modification of the fifth embodiment. Note that FIGS. 18A to 18C show some of the arrangement examples of the force control mechanism 510 in the modification of the fifth embodiment. Therefore, arrangements other than those shown in FIGS. 18A to 18C are not excluded as long as the force control mechanism 510 is attached to a part of the joints 405 of the working machine 400.

[0126] <5-1-2-1. First placement example> 18A, a force control mechanism 510 having a driving function and a load measurement function is disposed in a first joint portion 4051 and a second joint portion 4052. For example, a boom SEA 501 is disposed in the first joint portion 4051. An arm SEA is disposed in the second joint portion 4052. On the other hand, no force control mechanism 510 such as a bucket SEA 503 is disposed in the third joint portion.

[0127] In this way, the control unit 602 can detect the loads at the first joint portion 4051 and the second joint portion 4052, and can drive these joint portions 4051, 4052 with appropriate operation and driving force. Therefore, the work machine 400 can achieve flexible operation.

[0128] <5-1-2-2. Second placement example> 18B, a force control mechanism 510 having a driving function and a load measurement function is disposed in the third joint portion 4053. For example, a bucket SEA 503 is disposed in the third joint portion 4053. On the other hand, a force control mechanism 510 such as an SEA 500 is not disposed in the first joint portion 4051 and the second joint portion 4052.

[0129] The third joint portion 4053 has a smaller inertia during drive control than the other joint portions 4051, 4052. Therefore, the responsiveness of the drive control of the force control mechanism 510 attached to the third joint portion 4053 is good. Therefore, the work machine 400 can achieve precise and quick operation using only the tip portion. Also, a smaller and lighter force control mechanism 510 can be attached to the third joint portion 4053.

[0130] Note that the force control mechanism 510 attached to the work machine 400 is not limited to the first and second arrangement examples described above, and may be arranged at a location other than the first joint portion 4051 to the third joint portion 4053.

[0131] <5-1-2-3. Third arrangement example> 18C, a force control mechanism 510 having a driving function and a load measurement function is, for example, an SEA 500, and is disposed at the connection between the tip of the working machine 400 and a working member attached to the tip. The working member may be, for example, a hoisting tool 404, or an attachment such as a robot arm attached to the tip of the working machine 400. In this way, a smaller and lighter force control mechanism 510 can be attached to the tip of the working machine 400.

[0132] <5-1-2-4. Fourth placement example> In addition, the force control mechanism 510 (for example, the SEA 500) may be arranged not only in the joint portion 405 of the work machine 400 but also in the connection portion between the lower traveling body 200 and the upper rotating body 300. In this way, the control unit 602 can adjust the reaction force Fo in consideration of the rotation direction of the upper rotating body 300 relative to the lower traveling body 200.

[0133] In the above-mentioned first to fourth arrangement examples, the force control mechanism 510 has both a driving function and a load measurement function. However, this is not limited to the example, and the force control mechanism 510 having a driving function and the load measurement mechanism 520 may be arranged separately.

[0134] <5-1-3. Other variations> Alternatively, the excavator 100 may be provided with a mechanism having a function of driving at least one joint part 405 of the work machine 400 and a mechanism having a function of measuring the load acting on at least one joint part 405 of the work machine 400, which are separately arranged.

[0135] Fig. 19 is a schematic diagram showing an example of the arrangement of a force control mechanism 510 and a load measurement mechanism 520 according to another modified example of the fifth embodiment. Fig. 19 shows a part of an example of the arrangement of a mechanism having a function of driving at least one joint portion 405 of the work machine 400 and a mechanism having a function of measuring a load acting on at least one joint portion 405 of the work machine 400 in another modified example of the fifth embodiment. Therefore, the example in Fig. 19 does not exclude a configuration in which the arrangement of each of the above-mentioned mechanisms is other than that in Fig. 19.

[0136] 19, a force control mechanism 510 having a driving function is disposed at the third joint portion 4053, and a load measurement mechanism 520 is disposed at the base of the work machine 400 (for example, at the first joint portion 4051 or in its vicinity). In addition, in FIG. 19, the force control mechanism 510 may be realized by using only the driving function of the SEA 500, or may be an actuator capable of high-precision drive control different from the SEA 500. In FIG. 19, the load measurement mechanism 520 is, for example, a force sensor, and measures the load acting on the first joint portion 4051.

[0137] In this way, a smaller and lighter force control mechanism 510 can be attached to the tip of the work machine 400. In addition, by disposing a force sensor that is smaller and lighter than the SEA 500 or the like at the base of the work machine 400, it is easy to reflect the control of the reaction force Fo based on the measured load in the force control mechanism 510 and the joints 4051, 4052, 4053 of the work machine 400.

[0138] <5-2. Example of correction of driving direction and driving amount of the tip of the work machine 400> Next, an example of correction of the drive (direction and amount) of the tip of the work implement 400 will be described with reference to Fig. 20. Fig. 20 is a block diagram showing an example of correction of the drive of the tip of the work implement 400 by the control unit 602.

[0139] First, the control unit 602 estimates the reaction force Fo acting on the tip portion of the work machine 400 based on the load measurement function of the force control mechanism 510 or the detection result of the load measurement mechanism 520.

[0140] In a subtractor 6021, the control unit 602 calculates a difference value ΔF=(Fd−Fo) of the reaction force Fo with respect to the target reaction force Fd.

[0141] In the insensitive filter 6022, if the difference value ΔF is within a predetermined range (i.e., a dead zone), the control unit 602 stops the drive correction of the tip of the work machine 400, in other words, sets the correction value Pm for the drive direction and drive amount of the tip of the work machine 400 to 0. Note that the dead zone includes 0, and the numerical width of the dead zone (i.e., the difference between the upper limit value and the lower limit value) is sufficiently smaller than the reaction force Fo and the target reaction force Fd. This makes it possible to prevent the reaction force Fo from repeatedly increasing and decreasing slightly near the target reaction force Fd. In other words, it is possible to prevent an oscillatory increase and decrease in the correction value Pm (for example, a state in which the correction value Pm repeatedly increases and decreases around 0). Therefore, the reaction force Fo becomes more likely to converge to the target reaction force Fd. In other words, the correction value Pm becomes more likely to converge to 0.

[0142] On the other hand, in the insensitive filter 6022 , if the difference value ΔF is outside the insensitive zone, the control unit 602 outputs the difference value ΔF to the amplification unit 6023 .

[0143] In the amplifier 6023 , the control unit 602 amplifies the difference value ΔF with a predetermined gain, and outputs the amplified value Pg to the band-pass filter 6024 .

[0144] In the band pass filter 6024, if the amplification value Pg is a positive value and is greater than a predetermined value Pu (>0), the control unit 602 outputs the predetermined value Pu to the adder 6025. Also, if the amplification value Pg is a negative value and is smaller than a predetermined value Pd (<0), the control unit 602 outputs the predetermined value Pd to the adder 6025. The band pass filter 6024 can prevent the output value of the adder 6025 from deviating excessively from its target value.

[0145] On the other hand, in the band-pass filter 6024 , if the amplification value Pg is equal to or greater than the predetermined value Pd and equal to or less than the predetermined value Pu, the control unit 602 outputs the amplification value Pg to the adder 6025 .

[0146] Furthermore, in the adder 6025, the control unit 602 adds the most recent previous correction value Pma output from the delay circuit 6026 to the output value of the adder 6025 to obtain a correction value Pm. By performing the above-mentioned processing in the adder 6025, it is possible to correct the target position of the tip of the work machine 400. As a result, the control unit 602 brings the reaction force Fo acting on the tip closer to the target reaction force Fd.

[0147] The control unit 602 corrects the movement (that is, the driving direction and the driving amount) of the tip portion of the work machine 400 in response to the operation input based on the correction value Pm.

[0148] <5-3. Control mode examples> The control unit 602 can perform reaction force control in a plurality of control modes, including a lifting assist mode and a reaction force assist mode.

[0149] In the lifting assist mode, the target reaction force Fd is set to a constant value (for example, Fd=0). When a reaction force Fo of a magnitude outside the dead zone acts on the tip of the working implement 400, the tip of the working implement 400 is driven in a direction in which the magnitude of the reaction force Fo (=|Fo|) becomes smaller. As a result, even if the operating unit 301 does not operate the working implement 400, the tip of the working implement 400 can be driven in the above-mentioned direction by applying a reaction force Fo of a magnitude outside the dead zone in a desired direction.

[0150] In the reaction force assist mode, the magnitude of the target reaction force Fd is set to a predetermined value (|Fd| ≠ 0). Furthermore, the movement and driving force of the tip of the work implement 400 are limited by the magnitude of the target reaction force Fd. In this way, the driving (moving) range and driving force of the tip of the work implement 400 can be limited, so that the risk of damage to an object and / or the work implement 400 due to contact with the object can be reduced or prevented.

[0151] The control mode is switched, for example, by an operation input on the operation unit 301 or an operation input on a remote controller (not shown) for the control unit 602. The operation unit 301 and the remote controller transmit an output signal indicating the control mode according to the received operation input to the control unit 602.

[0152] <5-3-1. Control mode switching example> Fig. 21 is a flowchart showing an example of switching the control mode, which illustrates a process of setting the control mode to either the lifting assist mode or the reaction force assist mode.

[0153] First, when the control unit 602 receives a control mode selection signal (step S101), it determines whether or not the output signal indicates the reaction force assist mode (step S102).

[0154] If the output signal indicates the reaction force assist mode (YES in step S102), the control unit 602 sets the control mode to the reaction force assist mode (step S103). On the other hand, if the output signal does not indicate the reaction force assist mode (NO in step S102), the control unit 602 sets the control mode to the lifting assist mode (step S104).

[0155] Then, the control unit 602 implements the control mode set in the immediately previous step (that is, S103 or S104) (step S105).

[0156] Thereafter, when the control unit 602 receives the control mode selection signal again (Yes in step S106), the process returns to step S102.

[0157] The processing in FIG. 21 is started, for example, when the control unit 602 receives an output signal indicating the reaction force assist mode, and ends in response to the stopping of the excavator 100, the reception of a stop signal output from the operation unit 301, a remote controller, etc.

[0158] <5-3-2. Example of using control mode> Next, the first to fifth use examples of the control mode will be described.

[0159] (1st usage example) Conventionally, when performing lifting work with a work machine such as an excavator 100, the tip of the work machine 400 is operated by the operation unit 301 or a remote controller. In this case, an object lifted to the tip of the work machine 400 (e.g., the sling 404) by a wire or the like had to be manually guided by an operator other than the operator within the range in which the wire could move. This is because it is difficult for the operator to grasp the direction and magnitude of the reaction force Fo acting on the tip of the work machine 400, and there is a risk that a large load will be applied to the lifted object when it hits the ground, causing damage.

[0160] At this time, it is also important for the operator to communicate with the worker who guides the object at the tip of the working machine 400. For example, if the operator drives the working machine 400 before fully communicating his / her intentions to the worker, there is a risk of a contact accident occurring between the tip of the working machine 400 (such as the hoisting tool 404) and the lifted object and the worker.

[0161] In order to eliminate the above-mentioned concerns, the excavator 100 of the fifth embodiment can guide the tip of the working machine 400 and the object without remote control by applying an appropriate reaction force Fo to the tip of the working machine 400 using the lifting assist mode. In other words, by simply manually applying a load to the tip or the object, the tip of the working machine 400 and the object move in the direction of the load while maintaining a reaction force Fo according to the load. In other words, the working machine 400 can be operated by the operator's manual guidance. This allows one person to carry out work that previously required three people, for example, an operator, an operator who guides the object, and a supervisor who gives instructions to both of them.

[0162] (2nd usage example) Conventionally, when laying a U-shaped gutter, the U-shaped gutter is lifted by a work machine such as an excavator 100. The U-shaped gutter is a cement molded product with a U-shaped cross section, and is used by burying it on the ground surface for drainage purposes. A worker has to manually guide the U-shaped gutter to the ground and press the newly laid U-shaped gutter against the end of the existing U-shaped gutter. When pressing the gutter against the ground and the end of the existing U-shaped gutter, it is difficult for the operator to grasp the direction and magnitude of the reaction force Fo acting on the tip of the work machine 400. In addition, the newly laid U-shaped gutter may be damaged due to the large load applied.

[0163] To solve these problems, the excavator 100 of the fifth embodiment, for example, rigidly attaches a new U-shaped ditch to be laid to the tip of the working machine 400 and performs reaction force control in reaction force limit mode, making it possible to press the U-shaped ditch against the ground or the end of an existing U-shaped ditch with a certain force that does not damage the U-shaped ditch. In other words, even if there is no worker to guide it, the U-shaped ditch can be laid by operating the working machine 400 by using the reaction force limit mode. This makes it possible to perform the work with fewer people.

[0164] Furthermore, reaction force control can be performed by changing the conditions of the reaction force limit mode for each solid coordinate (i.e., three-dimensional position) of the tip of the working machine 400 or the target object (here, a U-shaped ditch). For example, the target reaction force Fd of the reaction force control and the limit value (e.g., predetermined values ​​Pu, Pd) of the band filter 6024 can be arbitrarily changed when pressing the work machine against the ground and when pressing the work machine against the end of an existing U-shaped ditch. Furthermore, since the reaction force control can be arbitrarily switched ON / OFF, it is possible to turn the reaction force control OFF to dig a trench for laying a U-shaped ditch, and then turn the reaction force control ON to continue laying the U-shaped ditch. This not only reduces the number of workers laying the U-shaped ditch, but also prevents people from entering the work area. Therefore, the safety of the laying work can be improved.

[0165] (3rd usage example) Conventionally, when laying interior panels for tunnels, ALC panels, etc., it is necessary to push the panel to be laid against the wall surface while butting it against the ends or brackets of surrounding panels. In a work machine such as an excavator 100, it is difficult for the operator to grasp the direction and magnitude of the reaction force Fo acting on the tip of the work machine 400 when pushing and butting the panel to be laid. Therefore, there is a risk that the newly laid panel and the existing panels will be damaged due to the large load applied to them. Therefore, conventionally, it was necessary for the operator to manually guide the panel as in the first use example.

[0166] In order to solve the above-mentioned problems, the excavator 100 of the fifth embodiment can press the panel to be laid against the wall surface with a certain force or butt the panel to be laid against the edge of an existing panel without risk of damage by reaction force control in the reaction force limit mode. In addition, since it is possible to detect contact with the edge and bracket of the existing panel, even if the panel to be laid is fragile, it can be made to come into soft contact instead of being butted against.

[0167] (4th usage example) Conventionally, in a work machine such as an excavator 100, an attachment can be attached to a bucket 403, or the bucket 403 can be replaced with another attachment. For example, a grass cutting attachment can be attached to or replaced with a tip of the work machine 400.

[0168] When the excavator 100 uses a mowing attachment to mow grass, it is necessary to press the mowing attachment against the ground with a certain force in parallel with the ground. For this reason, mowing operation with the excavator 100 using the mowing attachment is difficult.

[0169] In addition, for example, the Ministry of Land, Infrastructure, Transport and Tourism stipulates that mobile lawn mowers should be used on slopes with a gradient of 1:1.9 or less, and that mowing on slopes steeper than this should be done by an operator equipped with a brush cutter.

[0170] On the other hand, in the excavator 100 of the fifth embodiment, the reaction force Fo acting on the tip of the working machine 400 or the mowing attachment attached to the tip is controlled in the reaction force limit mode, so that the above-mentioned mowing operation can be easily performed. In addition, the target reaction force Fd and the limit value of the band filter (for example, the predetermined values ​​Pu, Pd) can be appropriately adjusted at the work site according to the condition of the ground, etc., using the adjustment dial of the controller, etc. Therefore, mowing work can be performed under more suitable conditions depending on the work situation. Furthermore, even when mowing work is performed on steep ground where a conventional mower cannot run, the working machine 400 can be extended from the flat ground, so that the mowing attachment at the tip of the working machine 400 can be pressed with a constant force parallel to the steep ground. In other words, even on steep ground where a worker would normally mow the grass directly, the excavator 100 of the fifth embodiment can easily perform mowing work.

[0171] Furthermore, by disposing a plurality of load measuring mechanisms 520, or load measuring mechanisms 520 capable of measuring torque centered on different axes, between the mowing attachment and the tip of the working machine 400, it is possible to measure the contact area of ​​the mowing attachment with the ground. This makes it possible to accurately adjust the attitude of the mowing attachment and the pressing efficiency against the ground. Therefore, the excavator 100 can appropriately mow even on steep slopes that cannot be worked on by conventional traveling mowers.

[0172] (5th usage example) Conventionally, removing snow from a roof is a dangerous task that is performed manually by a worker climbing onto the roof. However, when a person cannot climb onto the roof, a work machine such as an excavator 100 extends the boom 401 and arm 402 of the work implement 400 to remove the snow that has accumulated on the roof. However, at this time, it is difficult for the operator to grasp the force that the tip of the work implement 400 applies to the roof (in other words, the direction and magnitude of the reaction force Fo, which is the differential reaction force). Therefore, combined with the fact that visibility is easily reduced, there is a risk of an accident occurring, such as the bucket breaking through the roof.

[0173] To eliminate this risk, the backhoe 100 of the fifth embodiment can remove snow by moving the tip of the bucket 403 along the roof surface without damaging the roof through reaction force control in the control mode. Furthermore, by changing the teeth at the tip of the bucket 403 to a soft material such as resin, the backhoe 100 can remove snow from roofs made of various materials without causing damage.

[0174] <6. Sixth Embodiment> Next, a sixth embodiment will be described with reference to FIG. 22. FIG. 22 is a left side view showing a configuration example of the excavator 100 according to the sixth embodiment. In the sixth embodiment, a configuration different from the first to fifth embodiments and their modified examples will be described. In the sixth embodiment, the same components as those in the first to fifth embodiments and their modified examples are given the same reference numerals, and the description thereof may be omitted. In addition, the sixth embodiment can be arbitrarily combined with the first to fifth embodiments and their modified examples, so long as no particular contradiction occurs.

[0175] In the excavator 100 of the sixth embodiment, an attachment 407 is attached to the tip of the work machine 400 instead of the bucket 403. Also, an SEA 500 is disposed in each joint portion 405 of the work machine 400. For example, the SEA 500 is also disposed in a joint portion 4054 between the tip portion of the arm 402 and the base end portion of the attachment 407.

[0176] The attachment 407 holds and transports an object. The attachment 407 is rod-shaped in Fig. 22, but is not limited to this example and may be a member capable of gripping the object Ob, such as a robot hand.

[0177] Furthermore, a surface adjustment member 408 is disposed at the tip of the attachment 407. When holding the object Ob, the attachment 407 is abutted against the surface of the object Ob via the surface adjustment member 408.

[0178] The tip of the surface adjustment member 408 is capable of swinging in the yaw direction and pitch direction relative to the portion on the attachment 407 side, and more preferably is also capable of swinging in the roll direction.

[0179] In this way, when the attachment 407 holds the object Ob, the swinging of the tip of the surface adjustment member 408 allows the attachment 407 to abut against the object Ob without applying impact or excessive load to the object Ob and the attachment 407. Also, the tip surface of the surface adjustment member 408 can be easily made to conform to the surface of the object Ob without performing reaction force control (see the fifth embodiment). Therefore, the attachment 407 can hold the object Ob more easily.

[0180] At least the tip of the surface adjustment member 408 can be made of, for example, a spring coil, an elastic member such as rubber, an elastically deformable porous body such as a high-resilience sponge or a low-resilience sponge, or an elastically deformable material such as a bellows. Alternatively, a joint member such as a ball joint may be used for the surface adjustment member 408. In this joint member, one end is connected to the other end so as to be swingable in the yaw direction and pitch direction (as well as the roll direction). In this way, one end of the surface adjustment member 408 can be easily and passively aligned to the surface of the object Ob due to its configuration.

[0181] Preferably, the surface adjustment member 408 has an adsorption member 4081. The adsorption member 4081 is disposed on the tip surface of the surface adjustment member 408. The adsorption member 4081 may be a suction cup, or may be a member capable of vacuum adsorption, such as a vacuum adsorption pad or a vacuum chuck. In this way, when the surface adjustment member 408 is butted against the object Ob, the adsorption member 4081 can connect the tip of the surface adjustment member 408 to the surface of the object Ob. Therefore, the attachment 407 can hold the object Ob more easily. However, this example does not exclude a configuration in which the surface adjustment member 408 does not have the adsorption member 4081.

[0182] 22, the rotation axes R of the joint parts 405 extend in the same direction. For example, the rotation axis R1 of the first joint part 4051 and the boom SEA 501, the rotation axis R2 of the second joint part 4052 and the arm SEA 502, and the rotation axis R4 of the joint part 4054 and the SEA 500 disposed at the joint part 4054 are all parallel to each other. However, without being limited to the example of FIG. 22, the rotation axes R of some joint parts 405 do not have to be parallel to the rotation axes R of other joint parts 405.

[0183] For example, in Fig. 22, the rotation axes R1, R2, and R4 may extend in directions perpendicular to each other. In particular, one of the rotation axes R1, R2, and R4 may extend in the left-right direction, and the joint part 405 with the one axis as the rotation axis R may be rotatable in the pitch direction. The other axis may extend in the up-down direction, and the joint part 405 with the one axis as the rotation axis R may be rotatable in the yaw direction. The remaining axis may extend in the front-rear direction, and the joint part 405 with the one axis as the rotation axis R may be rotatable in the roll direction. In this way, the working machine 400 can be used as a multi-joint robot arm.

[0184] In the fifth and sixth embodiments, the configuration and control described above are applied to a work machine 400 equipped with an SEA 500. However, the present invention is not limited to this example, and the configuration and control described above can also be applied to a work machine equipped with a hydraulic actuator.

[0185] <7.Notes> The above describes the embodiments of the present invention. Note that the above embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each process, and that such modifications are within the scope of the present invention.

[0186] For example, in the present disclosure, the work machine 400 has three joint parts 405. However, this is not limited to this example, and the number of joint parts 405 that the work machine 400 has may be a number other than three.

[0187] <8. Summary> The embodiments described thus far will be summarized below.

[0188] For example, the drive unit 500 disclosed herein may be A driving device 500 that rotates a driven object M2, A motor unit 1, a reducer 2 for reducing the torque input from the motor unit 1; a shock absorber 3 that outputs the torque input from the reducer 2 to a driven object M2 from an output end 32 via an elastic portion 33; Equipped with At least a part of the shock absorbing device 3 is configured (first configuration) to be disposed on the opposite side of the drive target M2 from the motor unit 1 and the speed reducer 2.

[0189] The driving device 500 of the first configuration is as follows: A part of the shock absorber 3 may be arranged inside a through hole Mh arranged in the driven object M2 (second arrangement).

[0190] The drive device 500 disclosed herein also has A driving device 500 that rotates a driven object M2, A motor unit 1, a reducer 2 for reducing the torque input from the motor unit 1; a shock absorber 3 that outputs a torque input from the reducer 2 to the driven object M2 from an output end 32 via an elastic portion 33; Equipped with The shock absorber 3 is configured to be disposed inside a through hole Mh disposed in the driven object M2 (third configuration).

[0191] Any of the first to third drive devices 500 described above includes: The output shaft 22 of the reduction gear 2 is connected to the shock absorber 3 through a through hole Mh disposed in the driven object M2, The output end 32 of the shock absorber 3 may be configured to be connected to the driven object M2 (fourth configuration).

[0192] The drive device 500 disclosed herein also has A driving device 500 that rotates a driven object M2, A motor unit 1, a shock absorber 3 that outputs the torque of the motor unit 1 from an output end 32 via an elastic unit 33; a first reducer 2 that reduces the torque input from the shock absorber 3; Equipped with The shock absorber 3 is disposed between the motor unit 1 and the first reducer 2, The output end 32 of the shock absorber 3 is connected to the first reducer 2, The first output shaft 22 of the first reduction gear 2 is configured to be connected to the driven object M2 (fifth configuration).

[0193] Moreover, the driving device 500 of the fifth configuration described above has the following features: a second reducer 5 disposed between the motor unit 1 and the shock absorber 3 and configured to reduce the torque input from the motor unit 1; The second output shaft 52 of the second reducer 5 may be configured to be connected to the shock absorber 3 (sixth configuration).

[0194] Any one of the eleventh to fifth drive devices 500 may be configured as follows: A configuration (configuration 7) may be provided further including a sensor 4 for detecting the relative phase between the input end 31 of the shock absorber 3 and the output end 32 of the shock absorber 3.

[0195] Moreover, the driving device 500 having the seventh configuration is The input end 31 and the output end 32 are rotatable about a rotation axis R of the driven object M2, The sensor 4 may be configured (eighth configuration) to detect a relative phase (for example, a rotation angle difference) of one of the input end 31 and the output end 32 with respect to the other.

[0196] In addition, the 77th or 8th drive unit 500 is The input end 31 and the output end 32 are rotatable about a rotation axis R of the driven object M2, The sensor 4 is a first sensor 41 for detecting a first phase (e.g., a rotation angle) of the input end 31; a second sensor 42 for detecting a second phase (e.g., a rotation angle) of the output end 32; The ninth configuration may be such that:

[0197] Moreover, any one of the seventh to ninth drive devices 500 described above is At least a part of the sensor 4 may be arranged inside the through hole Mh of the drive target M2 (tenth configuration).

[0198] Moreover, the fifth or sixth driving device 500 described above is a sensor 4 for detecting a relative phase between an input end 31 of the shock absorber 3 and an output end 32 of the shock absorber 3; The input end 31 and the output end 32 of the shock absorber 3 are rotatable about a rotation axis R of the driven object M2, The sensor 4 is a third sensor 43 for detecting a third phase (for example, a rotation angle) of the motor output shaft 11 of the motor unit 1; a fourth sensor 44 that detects a fourth phase (for example, a rotation angle) of either the first input shaft 21 or the first output shaft 22 of the first reduction gear 2; The configuration may be an eleventh configuration.

[0199] Moreover, the fifth or sixth driving device 500 described above is a sensor 4 for detecting a relative phase between an input end 31 of the shock absorber 3 and an output end 32 of the shock absorber 3; The input end 31 and the output end 32 are rotatable about a rotation axis R of the driven object M2, The sensor 4 is a first rotation transmission member 471 that transmits rotation of the motor output shaft 11 of the motor unit 1 radially outward beyond the space between the motor unit 1 and the shock absorber 3; a second rotation transmission member 472 that transmits rotation of at least one of the output end portion 32 of the shock absorber 3, the first input shaft 21 of the first reduction gear 2, and the first output shaft 22 of the first reduction gear 2 radially outward from between the shock absorber 3 and the driven object M2; a fifth sensor 45 that detects a fifth phase (for example, a rotation angle) of the first rotation transmission member 471; A sixth sensor 46 that detects a sixth phase (for example, a rotation angle) of the second rotation transmission member 472; The twelfth configuration may be such that:

[0200] The work machine 100 disclosed herein also includes: The configuration (thirteenth configuration) includes any one of the first, third, and fifth driving devices 500 described above.

[0201] Moreover, the above-mentioned thirteenth work machine 100 is A working machine 400 having a joint portion 405 and attached to a base 303 so as to be able to swing; A control unit 602 for controlling the operation of the working machine 400 and the driving device 500; Further equipped with The driving device 500 is disposed in the joint portion 405 to drive the joint portion 405, The control unit 602 may be configured (14th configuration) to estimate the reaction force Fo acting on the tip of the work machine 400 based on the detection result of a load detection unit 4, 6, 520 for detecting the load acting on the joint portion 405.

[0202] Moreover, the above-mentioned fourteenth work machine 100 is The control unit 602 may be configured to control the driving of the work machine 400 and the driving device 500 based on the reaction force Fo and a target reaction force Fd (a fifteenth configuration).

[0203] Moreover, the fifteenth work machine 100 described above has An operation unit 301 that accepts operation input; A storage unit 601 for storing the target reaction force Fd; Further equipped with The target reaction force Fd may be set based on the operation input (sixteenth configuration).

[0204] Moreover, the fifteenth or sixteenth work machine 100 described above is The control unit 602 If the magnitude of the difference value ΔF of the reaction force Fo with respect to the target reaction force Fd (corresponding to |Pg|) is less than a predetermined value (corresponding to |Pu|, |Pd|), the drive of the work machine 400 and the drive device 500 is corrected based on the reaction force Fo, If the magnitude of the difference value ΔF (corresponding to |Pg|) is greater than or equal to the predetermined value (corresponding to |Pu|, |Pd|), the configuration may be such that the driving of the work machine 4000 and the driving device 500 is corrected based on the predetermined value (corresponding to |Pu|, |Pd|) (17th configuration).

[0205] Further, any one of the fifteenth to seventeenth working machines 100 described above, The control unit 602 If the difference value ΔF of the reaction force Fo relative to the target reaction force Fd is outside a predetermined range (corresponding to the dead zone in the dead filter 6023 in Figure 20), the configuration may be such that the drive of the tip of the work machine 400 is corrected based on the difference value ΔF (18th configuration). [Explanation of symbols]

[0206] 100 Excavator 200 Undercarriage 201 Crawler 202 Driving motor 300 Upper rotating body 301 Operation section 3011 Cockpit 3012 Operation lever 3013 Travel lever 3014 Control panel 302 Motor 303 Swivel base (base) 304 Swing motor 400 Work Machine 401 Boom 402 Arm 403 Bucket 404 Lifting equipment 405 Joints 4051 First joint part 4052 Second joint part 4053 Third joint part 4054 Joints 406 Connection 407 Attachment 408 Surface adjustment member 500 SEA (drive unit) 501 Boom SEA 502 Arm SEA 503 Bucket SEA 510 Force Control Mechanism 520 Load measurement mechanism (load detection unit) 601 Storage section 602 Control section 6021 Differentiator 6022 Insensitive Filter 6023 Amplifier 6024 Bandpass Filter 6025 Adder 6026 Delay Circuit 1 Motor section 11 Motor output shaft 2,5 reducer 21,51 Input shaft 22,52 Output shaft 23 Gear mechanism 3 Shock absorber 31 Input end 32 Output end 33,331,332,333,334 Elastic part 34 Elastic member 341 Aisle 35 Stopper 351 First stopper 3511 First base 3512 1st restraint section 3513 1st aisle 352 Second Stopper 3521 Second base 3522 2nd restraint section 3523 2nd aisle 353 Groove 4 Sensor (load detection section) 41 First Sensor 42 Second Sensor 43 3rd Sensor 44 4th Sensor 45 5th Sensor 46 6th Sensor 471 First rotation transmission member 472 Second rotation transmission member 5 Reducer 51 Input shaft 52 Output shaft 6 Displacement sensor (load detection section) 61 Wiring M1 First member M2 2nd member Mh through hole R, R1, R2, R3, R4 Rotation axis

Claims

1. A drive device that rotates a driven object, A motor unit; a reducer that reduces the torque input from the motor unit; a shock absorber that outputs a torque input from the reducer to the driven object from an output end portion via an elastic portion; Equipped with A drive device, wherein at least a portion of the buffer device is disposed on an opposite side of the driven object from the motor unit and the reducer.

2. The drive unit according to claim 1 , wherein a portion of the shock absorber is disposed inside a through hole disposed in the driven target.

3. A drive device that rotates a driven object, A motor unit; a reducer that reduces the torque input from the motor unit; a shock absorber that outputs a torque input from the reducer to the driven object from an output end portion via an elastic portion; Equipped with The shock absorber is disposed inside a through hole disposed in the driven object.

4. an output shaft of the reducer is connected to the shock absorber through a through hole disposed in the driven object; The drive device according to claim 1 , wherein the output end of the shock absorber is connected to the driven object.

5. A drive device that rotates a driven object, A motor unit; a shock absorber that outputs the torque of the motor unit from an output end portion via an elastic portion; a first reducer that reduces the torque input from the shock absorber; Equipped with The shock absorber is disposed between the motor unit and the first reducer, The output end of the shock absorber is connected to the first reducer, A drive device, wherein a first output shaft of the first reducer is connected to the driven object.

6. a second reducer disposed between the motor unit and the shock absorber, the second reducer reducing the torque input from the motor unit; The drive device according to claim 5 , wherein a second output shaft of the second reducer is connected to the shock absorber.

7. 7. The drive arrangement of claim 1, further comprising a sensor for detecting a relative phase between an input end of the shock absorber and the output end of the shock absorber.

8. The input end and the output end are rotatable about a rotation axis of the driven object, The drive device according to claim 7 , wherein the sensor detects a relative phase of one of the input end and the output end with respect to the other.

9. The input end and the output end are rotatable about a rotation axis of the driven object, The sensor includes: a first sensor for detecting a first phase of the input end; a second sensor for detecting a second phase of the output end; The drive arrangement according to claim 7 , further comprising:

10. The driving device according to claim 7 , wherein at least a portion of the sensor is disposed within the through hole of the driven object.

11. a sensor for detecting a relative phase between an input end of the shock absorber and an output end of the shock absorber; The input end and the output end are rotatable about a rotation axis of the driven object, The sensor includes: a third sensor for detecting a third phase of a motor output shaft of the motor unit; a fourth sensor that detects a fourth phase of either the first input shaft or the first output shaft of the first reduction gear; The drive arrangement according to claim 5 , further comprising:

12. a sensor for detecting a relative phase between an input end of the shock absorber and an output end of the shock absorber; The input end and the output end are rotatable about a rotation axis of the driven object, The sensor includes: a first rotation transmission member that transmits rotation of a motor output shaft of the motor unit radially outward beyond a gap between the motor unit and the shock absorber; a second rotation transmission member that transmits rotation of at least one of the output end portion of the shock absorber, the first input shaft of the first reducer, and the first output shaft of the first reducer radially outward from between the shock absorber and the driven object; a fifth sensor that detects a fifth phase of the first rotation transmission member; a sixth sensor that detects a sixth phase of the second rotation transmission member; The drive arrangement according to claim 5 , further comprising:

13. A working machine comprising a drive device according to any one of claims 1 to 5.

14. A working machine having a joint portion and attached to a base so as to be swingable; A control unit that controls the operation of the working machine and the driving device; Further equipped with The drive device is disposed at the joint portion and drives the joint portion; The work machine according to claim 13 , wherein the control unit estimates a reaction force acting on a tip portion of the work implement based on a detection result of a load detection unit for detecting a load acting on the joint portion.

15. The work machine according to claim 14, wherein the control unit controls driving of the work implement and the drive device based on the reaction force and a target reaction force.

16. an operation unit that accepts operation input; A storage unit that stores the target reaction force; Further equipped with The work machine according to claim 15 , wherein the target reaction force is set based on the operation input.

17. The control unit is if the magnitude of the difference value of the reaction force with respect to the target reaction force is less than a predetermined value, correcting the drive of the work machine and the drive device based on the reaction force; The work machine according to claim 15, wherein, if the magnitude of the difference value is equal to or greater than the predetermined value, drive of the work implement and the drive device is corrected based on the predetermined value.

18. The control unit is The work machine according to claim 15, wherein, if a difference value of the reaction force from the target reaction force is outside a predetermined range, drive of the tip of the work machine is corrected based on the difference value.

Images