Electric chain block

Abstract

The present invention allows for a more compact electric chain block and provides an electric chain block that can be mounted with relatively low mounting precision on a rotary shaft.　Provided is an electric chain block 10 for lifting and lowering a load, the electric chain block comprising: a magnet 210 mounted on a rotary shaft 60 that transmits a driving force from a motor 21, the magnetic poles of the magnet changing along the circumferential direction; and a magnetic sensor 220 which is disposed in state of non-contact with the magnet 210 and which detects the magnetic field of the magnet 210, wherein the magnet 210 is mounted on the leading-end side of the rotary shaft 60 before the driving force of the motor 21 is reduced by a reduction mechanism 80, the magnetic sensor 220 is disposed at a position offset a prescribed distance from the axis of the rotary shaft 60 and outputs at least two detection signals of different phase, and the at least two detection signals of different phase are a detection signal for a longitudinal magnetic field, which is a magnetic field along the axial direction, and a detection signal for a transverse magnetic field orthogonal to the longitudinal magnetic field.

Description

Electric Chain Hoist

[0001] The present invention relates to an electric chain hoist.

[0002] Electric chain hoists are widely used to raise and lower loads using the driving force of a motor. For example, in such electric chain hoists, an adapter member is attached to the tip of the rotating shaft on which the pinion gear is formed, and an encoder device can be attached later via the adapter member or a coupling (Patent Document 1).

[0003] JP 2017-132560 A

[0004] The configuration disclosed in Patent Document 1 uses a relatively large encoder device as shown in Fig. 4. In particular, Patent Document 1 uses an optical encoder that uses a rotating disk, such as an absolute type or incremental type. However, because the rotating disk of such an encoder device is relatively large, it is difficult to use it in a small electric chain hoist.

[0005] Furthermore, when the size of the turntable is reduced, the requirement for concentricity between the turntable and the rotating shaft to which it is attached increases. Furthermore, if a small encoder device is used, it becomes very expensive, which increases the cost of manufacturing the electric chain hoist.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric chain hoist equipped with a magnetic sensor that can detect rotation with a simple configuration.

[0007] In order to solve the above-mentioned problems, according to a first aspect of the present invention, there is provided an electric chain hoist that includes a motor, a speed reduction mechanism, a brake mechanism, and a load sheave, and that raises and lowers a load by transmitting driving force from the motor to the load sheave via the speed reduction mechanism, the electric chain hoist comprising: a magnet that is attached to a rotating shaft that transmits the driving force from the motor and whose magnetic polarity changes along the circumferential direction; and a magnetic sensor that is arranged in a non-contact manner in the vicinity of the magnet and detects the magnetic field of the magnet, the tip side of the rotating shaft passes through a through hole that penetrates the brake mechanism, the magnet is attached to the tip side of the rotating shaft before the driving force of the motor is reduced by the speed reduction mechanism, the magnetic sensor is arranged at a position offset by a predetermined distance from the axis of the rotating shaft, and outputs at least two detection signals with different phases, the at least two detection signals with different phases being a detection signal of a vertical magnetic field (Z), which is a magnetic field that is input to the magnetic sensor in a state along the axial direction of the rotating shaft, and a detection signal of a horizontal magnetic field (X), which is a magnetic field that is input to the magnetic sensor in a state perpendicular to the vertical magnetic field.

[0008] Furthermore, in order to solve the above-mentioned problems, according to a second aspect of the present invention, there is provided an electric chain hoist that includes a motor, a speed reduction mechanism, a brake mechanism, and a load sheave, and that raises and lowers a load by transmitting driving force from the motor to the load sheave via the speed reduction mechanism, the electric chain hoist comprising: a magnet that is attached to a rotating shaft that transmits the driving force from the motor and whose magnetic polarity changes along the circumferential direction; and a magnetic sensor that is arranged in a non-contact manner in the vicinity of the magnet and detects the magnetic field of the magnet, the tip side of the rotating shaft passes through a through hole that penetrates the brake mechanism, the magnet is attached to the tip side of the rotating shaft before the driving force of the motor is reduced by the speed reduction mechanism, the magnetic sensor is arranged on the axis of the rotating shaft and outputs at least two detection signals with different phases, and the at least two detection signals with different phases are detection signals of a transverse magnetic field (X, Y), which is a magnetic field that is input to the magnetic sensor in a state perpendicular to the axial direction of the rotating shaft.

[0009] In another aspect of the present invention, in the above-mentioned invention, the magnetic sensor is preferably a bipolar output type that can detect magnetic fields in two different directions.

[0010] Another aspect of the present invention is that, in the above-mentioned invention, the magnetic sensor is attached to a sub-board different from the main control board that controls the motor, and the sub-board is attached in a manner that blocks the opening of a through-hole that passes through a fixed portion of a brake mechanism that stops the rotation of the rotating shaft, and is preferably facing a magnet on the side opposite to the side on which the magnetic sensor is mounted.

[0011] Another aspect of the present invention is that, in the above-mentioned invention, the brake mechanism preferably includes a stator and an armature that forms a magnetic circuit together with the stator, and the sub-substrate is attached to the side of the stator opposite to the side on which the armature is arranged.

[0012] According to the present invention, it is possible to provide an electric chain hoist equipped with a magnetic sensor that can detect rotation with a simple configuration.

[0013] It is a perspective view showing the overall configuration of the main body of an electric chain block according to an embodiment of the present invention. It is a partial perspective view showing the drive transmission path from the motor unit to the load sheave member and the configuration near the control unit among the electric chain blocks shown in FIG. 1. It is a cross-sectional view showing the configuration from the motor unit to the brake mechanism in the electric chain block shown in FIG. 1. It is a perspective view including a partial cross-sectional view showing the configuration of the brake mechanism 70 in the electric chain block shown in FIG. 1. It is a diagram showing a schematic configuration of the magnetic encoder unit in the electric chain block shown in FIG. 1. It is a perspective view showing the configuration of the magnetic sensor of the magnetic encoder unit shown in FIG. 5. It is a schematic side view showing a state in which the longitudinal magnetic field (Z) is detected but the transverse magnetic field is not detected in the magnetic encoder unit shown in FIG. 5. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 7A when viewed from the front. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 7A when viewed in plan. It is a schematic side view showing a state in which the longitudinal magnetic field (Z) is not detected but the transverse magnetic field (X) is detected in the magnetic encoder unit shown in FIG. 5. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 8A when viewed from the front. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 8A when viewed in plan. It is a schematic side view showing a state in which the longitudinal magnetic field (Z) is detected but the transverse magnetic field (X) is not detected in the magnetic encoder unit shown in FIG. 5, while the direction of detection of the longitudinal magnetic field (Z) is opposite to that in FIG. 7A. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 9A when viewed from the front. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 9A when viewed in plan. It is a schematic side view showing a state in which the longitudinal magnetic field (Z) is not detected but the transverse magnetic field (X) is detected in the magnetic encoder unit shown in FIG. 5, while the direction of detection of the transverse magnetic field (X) is opposite to that in FIG. 8A. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 10A when viewed from the front. It is a view showing the state of the magnetic encoder unit in the state shown in FIG. 10A when viewed in plan. It is a diagram showing the detection signal output from the magnetic sensor to the main control board in the magnetic encoder unit shown in FIG. 5.12A is a schematic side view showing a state in which a transverse magnetic field (Y) is detected but a transverse magnetic field (X) is not detected in a magnetic encoder unit having an arrangement different from that shown in FIG. 5. FIG. 12B is a diagram showing a front view of the magnetic encoder unit in the state shown in FIG. 12A. FIG. 12B is a diagram showing a plan view of the magnetic encoder unit in the state shown in FIG. 12A. FIG. 12C is a schematic side view showing a state in which a transverse magnetic field (X) is detected but a transverse magnetic field (Y) is not detected in a magnetic encoder unit having an arrangement different from that shown in FIG. 5. FIG. 13A is a diagram showing a front view of the magnetic encoder unit in the state shown in FIG. 13A. FIG. 13B is a diagram showing a plan view of the magnetic encoder unit in the state shown in FIG. 5. FIG. 13C is a diagram showing a detection signal output by a magnetic sensor to a main control board in a magnetic encoder unit having an arrangement different from that shown in FIG. 5.

[0014] An electric chain hoist 10 according to an embodiment of the present invention will be described below with reference to the drawings. In the following description, an XYZ Cartesian coordinate system will be used as necessary. In the XYZ Cartesian coordinate system, the X direction is the axial direction of the rotating shaft 60 in FIG. 2 , with the X1 side indicating the upper left side in FIG. 2 and the X2 side indicating the opposite lower right side. The Z direction is the direction in which a load is suspended, with the Z1 side indicating the back side of the paper in FIGS. 1 and 2 and the Z2 side indicating the opposite front side of the paper. The Y direction is the direction perpendicular to the X and Z directions, with the Y1 side indicating the upper right side in FIG. 2 and the Y2 side indicating the opposite lower left side.

[0015] <Overall Configuration of Chain Block> Figure 1 is a perspective view showing the configuration of an electric chain block 10. Figure 2 is a partial perspective view showing the drive transmission path from the motor unit 20 to the load sheave member 90 and the configuration in the vicinity of the control unit 110 of the electric chain block 10. As shown in Figures 1 and 2, the electric chain block 10 includes the motor unit 20, a body 50, a rotating shaft 60, a brake mechanism 70, a reduction gear mechanism 80, the load sheave member 90, a hook 100, the control unit 110, and a magnetic encoder unit 200.

[0016] In the electric chain hoist 10 shown in Figures 1 and 2, the driving force from the motor unit 20 is transmitted to the rotating shaft 60 and the reduction gear mechanism 80, where it is reduced at a predetermined reduction ratio. After that, the driving force is transmitted to the load sheave member 90 arranged in the body 50, causing the load sheave member 90 to rotate.

[0017] Here, a load chain (not shown) is wound around the load sheave member 90, and by winding up or down the load chain, the electric chain block 10 moves up and down, and the load suspended from the hook 100 connected to the body 50 of the electric chain block 10 can be moved up and down.

[0018] Next, the motor unit 20 will be described. Fig. 3 is a cross-sectional view showing the configuration from the motor unit 20 to the brake mechanism 70. As shown in Fig. 3, the motor unit 20 includes a motor 21, a motor shaft 30, and a friction clutch mechanism 40. The motor 21 includes a stator 22 around which a coil is wound, and a rotatable rotor 23.

[0019] A motor shaft 30 is inserted through a central hole 23a of the rotor 23. One end of the motor shaft 30 is supported by a motor holder 51 via a bearing B1, and the other end is connected to a rotary shaft 60 via a coupling C1.

[0020] The motor holder 51 is a part that is fixed to the body 50, for example, via screws. The body 50 also has a portion that supports the stator 22. The body 50, motor holder 51, etc. house various components of the electric chain hoist 10 and protect these components. The body 50, motor holder 51, etc. also support the entire electric chain hoist 10.

[0021] A bearing B4 and a friction clutch mechanism 40 are provided between the rotor 23 and the motor shaft 30. The rotor 23 is supported on the motor shaft 30 by the bearing B4. The friction clutch mechanism 40 transmits the motor torque of the rotor 23 of the motor 21 to the motor shaft 30 and prevents an overload exceeding a predetermined value, which exceeds the rated torque, from being transmitted from the motor 21 to the motor shaft 30. The friction clutch mechanism 40 includes a friction disk 41, a sliding disk 42, a spring bearing member 43, and a biasing spring 44. The friction disk 41 is fixed to the rotor 23 and has a predetermined friction coefficient. The sliding disk 42 rotates integrally with the motor shaft 30 and has a flange portion 42a that is pressed against the friction disk 41. The spring bearing member 43 holds the biasing spring 44 between the sliding disk 42 and a surface opposite to the surface facing the friction disk 41. The biasing spring 44 is a spring member, such as a disc spring, that is disposed between the sliding disk 42 and the spring receiving member 43 and applies a biasing force to press the flange portion 42 a of the sliding disk 42 against the friction disk 41 .

[0022] As described above, the rotating shaft 60, which is connected to the motor shaft 30 via the coupling C1, is provided with a gear portion 61, which meshes with the first driven gear 81 of the reduction gear mechanism 80. The rotating shaft 60 is inserted through an insertion hole (not shown) in the body 50 and is journaled by a plurality of bearings B2, B3 (two in FIG. 3 ). The rotating shaft 60 is inserted through a through hole 79 in the brake mechanism 70.

[0023] Here, the brake mechanism 70 is, for example, a non-excitation operated electromagnetic brake, and is a mechanism that stops the rotation of the rotating shaft 60. The brake mechanism 70 has, for example, a configuration as shown in Fig. 4. As shown in Fig. 4, the brake mechanism 70 has, as its main components, a stator 71, a coil 72, an armature 73, a support shaft 74, a biasing spring 75, a plate 76, a rotor 77, and a rotor hub 78.

[0024] Of these, the stator 71, coil 72, armature 73, biasing spring 75, and plate 76 are parts that do not rotate even when the rotating shaft 60 rotates, and correspond to fixed parts. On the other hand, the rotor 77 and rotor hub 78 are parts that rotate together with the rotating shaft 60 when the rotating shaft 60 rotates.

[0025] The stator 71 and the armature 73 constitute a magnetic circuit and are made of a magnetic material such as an iron-based metal. Of these, the stator 71 is a part that is fixed to the body 50 or the like, and has a coil 72 disposed in a recess 71a thereof. The coil 72 is a part that generates an electromagnetic force when current is passed through it, in order to attract the armature 73 to the stator 71.

[0026] The armature 73 is a member that is provided movably relative to the stator 71 via the support shaft 74, and is attracted to the stator 71 when current is applied to the coil 72 as described above. The armature 73 is a member that brakes the rotor 77 by sandwiching the rotor 77 together with the plate 76 while being in close contact with the rotor 77. The support shaft 74 is a shaft-shaped part that supports the armature 73 movably relative to the stator 71 while maintaining a constant distance between the stator 71 and the plate 76.

[0027] The biasing spring 75 is a member having one end inserted into the recess 71b of the stator 71 and disposed between the stator 71 and the armature 73, and applies a biasing force that presses the armature 73 against the rotor 77 (the plate 76). Therefore, when the current to the coil 72 is cut off, the armature 73 clamps the rotor 77 between itself and the plate 76 due to the biasing force of the biasing spring 75, thereby braking the rotor 77.

[0028] The plate 76 is a member that is arranged on the opposite side of the stator 71 across the rotor 77, and is a member that sandwiches the rotor 77 together with the armature 73, comes into close contact with the rotor 77, and brakes the rotor 77.

[0029] The rotor 77 is a disk-shaped member that rotates together with the rotary shaft 60. The rotor hub 78 is connected to the rotary shaft 60 by, for example, a key connection or a spline connection, and rotates together with the rotary shaft 60. The rotor hub 78 is also provided integrally with the rotor 77, and rotates integrally with the rotor 77.

[0030] In the non-excitation actuated electromagnetic brake that is the brake mechanism 70 described above, the rotor 77 is pressed against the armature 73 and the plate 76 when the coil 72 is not energized. However, when the coil 72 is energized, the above-mentioned pressed state is released, the rotating shaft 60 becomes rotatable, and the driving force of the motor 21 can be transmitted to the load sheave member 90.

[0031] 3, one brake mechanism 70 is provided, but a configuration in which, for example, two or more electromagnetic brakes are provided may be adopted.Furthermore, a configuration in which a mechanical brake other than an electromagnetic brake is provided may also be adopted.

[0032] A through-hole 79 is provided in the radial center of the brake mechanism 70, passing through the brake mechanism 70 along the axial direction (X direction). The rotary shaft 60 is inserted through this through-hole 79.

[0033] The reduction gear mechanism 80 includes a plurality of gear portions including the first driven gear 81 that meshes with the gear portion 61 of the rotating shaft 60 described above, and the plurality of gear portions includes a load gear 82. The load gear 82 is provided so as to rotate integrally with the load sheave member 90 by, for example, a key connection or a spline connection. The reduction gear mechanism 80 corresponds to a reduction mechanism, but the reduction mechanism may include a driving force transmission member other than gears, such as a belt or pulley.

[0034] The load sheave member 90, to which the driving force is transmitted from the load gear 82, has a plurality of pockets into which the load chain fits. A load chain (not shown) is looped around the load sheave member 90, and the electric chain hoist 10 (body 50) can be moved up and down by winding up or down the load chain. A hook 100 is connected to the body 50, and as the electric chain hoist 10 (body 50) moves up and down, the hook 100 and the load suspended from this hook 100 also move up and down.

[0035] The control unit 110 controls the drive of the motor 21 in response to the operation of an operation switch (not shown) or the like. The control unit 110 includes a main control board 111 that controls the drive of the motor 21, and also includes a sub-board 112 on which a magnetic sensor 220 of the magnetic encoder unit 200 (described later) is mounted. The main control board 111 and the sub-board 112 are printed circuit boards on which various electronic components are mounted, and the printed circuit boards are mainly made of non-magnetic materials such as glass or copper. Therefore, magnetism can pass through the sub-board 112 (main control board 111).

[0036] 3, the main control board 111 is attached to the cover 52 that constitutes a part of the body 50 via, for example, screws or bolts. The sub-board 112 is attached to an end face on one side (X1 side) in the axial direction (X direction) of the brake mechanism 70. The sub-board 112 is attached to, for example, the stator 71 of the brake mechanism 70, but may also be attached to the plate 76.

[0037] This sub-board 112 is attached in a state in which it covers the opening at one end (X1 side) of the through-hole 79. This prevents brake dust generated when the brake mechanism 70 is applied from adhering to a magnetic sensor 220 (described later) on the sub-board 112. Furthermore, by separating the sub-board 112 from the main control board 111, the sub-board 112 can be attached directly to the stator 71, making it easier to align the rotating shaft 60 and the magnetic sensor 220. Furthermore, since the distance between the magnet 210 at the tip of the rotating shaft 60 (described later) and the magnetic sensor 220 can be easily reduced, the detection accuracy of the magnetic encoder unit 200 (magnetic sensor 220) can be improved.

[0038] The sub-board 112 has a magnetic sensor 220 (described later) and a connector (not shown) for electrically connecting to the magnetic sensor 220 arranged on its surface. The surface of the sub-board 112 here refers to the surface on one side (X2 side) of the sub-board 112. The surface side of the sub-board 112 faces the main control board 111.

[0039] <Magnetic Encoder Unit 200> Next, a description will be given of the magnetic encoder unit 200. Fig. 5 is a diagram showing a schematic configuration of the magnetic encoder unit 200. The magnetic encoder unit 200 includes a magnet 210 and a magnetic sensor 220.

[0040] The magnet 210 is attached to the tip (X2 side) of the rotating shaft 60 in the axial direction (X direction). In this embodiment, as shown in Fig. 5, a recess 62 is provided recessed from the end face on the tip side of the rotating shaft 60, and the magnet 210 is attached to the rotating shaft 60 so that the magnet 210 fits into this recess 62. Therefore, the magnet 210 is attached concentrically with the rotating shaft 60. However, instead of being directly attached to the recess 62, the magnet 210 may be attached to the rotating shaft 60 via a casing made of a non-magnetic material such as an aluminum-based metal.

[0041] This magnet 210 is provided, for example, in a cylindrical shape, and when viewed from the front, the half circle is magnetized to the north pole and the remaining half circle is magnetized to the south pole. However, the magnetization direction of the magnet 210 is not limited to this, and it may be magnetized in a direction such as four poles on both sides or two poles on one side.

[0042] 6 is a perspective view showing the configuration of the magnetic sensor 220. The magnetic sensor 220 is mounted on the surface of the sub-board 112 opposite to the surface that covers the through-hole 79 (the surface facing the through-hole 79). The magnetic sensor 220 outputs a detection signal according to the two directions of the magnetic lines of force that pass through the magnetic sensor 220. Specifically, in this embodiment, as shown in FIG. 6 , when a center line along the longitudinal direction of the magnetic sensor 220 is defined as M, the detection signals are directed in two directions that are perpendicular to the center line M and pass through the magnetic sensor 220 itself (the short-side direction (width direction) of the magnetic sensor 220 and the thickness direction of the magnetic sensor 220).

[0043] Here, of the two directions mentioned above, the magnetic field formed by magnetic lines of force that run through the magnetic sensor 220 along the thickness direction of the magnetic sensor 220 is referred to as the vertical magnetic field (Z), and the magnetic field formed by magnetic lines of force that run through the magnetic sensor 220 along the short direction of the magnetic sensor 220 is referred to as the horizontal magnetic field (X). Note that the letters of the vertical magnetic field (Z) and the horizontal magnetic field (X) do not refer to the Z direction and the X direction mentioned above.

[0044] In addition, the magnetic sensor 220 outputs to the main control board 111 any direction of the magnetic field lines in the vertical magnetic field (Z) (for example, the direction of the magnetic field lines from top to bottom in FIG. 6 ) as positive, and the opposite direction of the magnetic field lines (for example, the direction of the magnetic field lines from bottom to top in FIG. 6 ) as negative. Similarly, the magnetic sensor 220 outputs to the main control board 111 any direction of the magnetic field lines in the horizontal magnetic field (X) (for example, the direction of the magnetic field lines from left to right in FIG. 6 ) as positive, and the opposite direction of the magnetic field lines (for example, the direction of the magnetic field lines from right to left in FIG. 6 ) as negative. However, the magnetic sensor 220 may be capable of detecting not only positive and negative magnetic fields in each of the vertical magnetic field (Z) and the horizontal magnetic field (X) as described above, but also the magnetic quantity in each of the vertical magnetic field (Z) and the horizontal magnetic field (X).

[0045] The magnetic sensor 220 may be, for example, a Hall IC incorporating a Hall element, a GSR sensor, or a magnetoresistive sensor incorporating a magnetoresistive effect element, but various other magnetic sensors may also be used.

[0046] Such magnetic sensor 220 is disposed at a position where the vertical magnetic field (Z) and horizontal magnetic field (X) are reversed as magnet 210 rotates, making it possible to easily detect the rotation of rotation shaft 60. Specific positions of magnet 210 and magnetic sensor 220 for such detection are as shown in Fig. 5 , where they are disposed at a predetermined distance from magnet 210 in the axial direction (X direction). In addition, as shown in Fig. 7A , which will be described later, magnetic sensor 220 is disposed at a predetermined distance from axis L of rotation shaft 60 (a position that is a predetermined distance from axis L in a YZ plane perpendicular to the X direction; a position offset from axis L).

[0047] 8C, which will be described later, it is preferable that the magnetic sensor 220 be arranged so that the center line M passes substantially through the boundary line P between the north and south poles at any rotation angle of the magnet 210. In this arrangement, the magnetic field lines from the north pole can easily penetrate the magnetic sensor 220 when heading toward the south pole, resulting in good detection of the transverse magnetic field (X).

[0048] As described above, by arranging the magnetic sensor 220 relative to the magnet 210, the magnetic sensor 220 can accurately detect whether the vertical magnetic field is positive or negative, and can also accurately detect whether the horizontal magnetic field (X) is positive or negative.

[0049] <Regarding Operation> In the electric chain block 10 having the above-described configuration, detection by the magnetic encoder unit 200 when the electric chain block 10 is in operation will be described below.

[0050] When the motor 21 of the electric chain hoist 10 is operated, the driving force is transmitted from the rotor 23 to the motor shaft 30 and the rotating shaft 60 via the friction clutch mechanism 40. As a result, the magnet 210 constituting the magnetic encoder unit 200 rotates together with the rotating shaft 60. Then, in response to this rotation, the magnetic sensor 220 of the magnetic encoder unit 200 detects a magnetic field (changes in the magnetic field).

[0051] The detection of this magnetic field (change in magnetic field) will be described with reference to Figures 7A to 7C, 8A to 8C, 9A to 9C, and 10A to 10C. Figure 7A is a schematic side view showing a state in which the magnetic encoder unit 200 detects the vertical magnetic field (Z) but does not detect the horizontal magnetic field (X). Figure 7B is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 7A as viewed from the front. Figure 7C is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 7A as viewed from above. Note that in Figures 7A and 7C, the hatched portion of the magnet 210 represents the north pole, and the white portion represents the south pole (the same applies to the other figures).

[0052] In the state shown in FIG. 7A , the magnetic sensor 220 can detect a magnetic field that penetrates the magnetic sensor 220 itself and intersects with the sub-board 112 (orthogonal in FIG. 7A ) as a vertical magnetic field (Z). At this time, the boundary P between the north and south poles of the magnet 210 does not penetrate the magnetic sensor 220. Therefore, in the state shown in FIG. 7C , the magnetic field lines extend in either direction relative to the center line M, making it impossible for the magnetic sensor 220 to distinguish the direction of the magnetic field lines of the transverse magnetic field (X). In other words, in the states shown in FIGS. 7A to 7C , the magnetic sensor 220 outputs either a positive or negative value (e.g., a positive value) for the vertical magnetic field (Z) to the main control board 111, but does not output either a positive or negative value for the transverse magnetic field (X) (it does not reach either the positive or negative threshold).

[0053] When the magnet 210 rotates together with the rotating shaft 60 from the state shown in Figures 7A to 7C, the state changes to the states shown in Figures 8A to 8C. Note that Figure 8A is a schematic side view showing a state in which the magnetic encoder unit 200 does not detect a vertical magnetic field (Z) but detects a horizontal magnetic field (X). Figure 8B is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 8A as viewed from the front. Figure 8C is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 8A as viewed from above.

[0054] 8B and 8C, the magnetic sensor 220 can detect a magnetic field that runs along the sub-substrate 112 and penetrates the magnetic sensor 220 (the short side direction of the magnetic sensor 220) as a transverse magnetic field (X). At this time, in the magnetic sensor 220, the boundary line P between the north and south poles is oriented in roughly the same direction as the center line M of the magnetic sensor 220, as shown in Fig. 8C. Therefore, in the state shown in Fig. 8B and 8C, the magnetic field lines run through the magnetic sensor 220 while intersecting the center line M, and therefore can be detected as a transverse magnetic field (X) by the magnetic sensor 220.

[0055] 8A, since the state is rotated 90 degrees from the state shown in Fig. 8A, only a very weak vertical magnetic field (Z) that does not exceed the threshold value of the vertical magnetic field (Z) can be detected for the magnetic field that penetrates the magnetic sensor 220 in a direction that intersects with the sub-substrate 112, and the vertical magnetic field (Z) cannot be detected. That is, in the states shown in Figs. 8A to 8C, the magnetic sensor 220 outputs either a positive or negative value (for example, a positive value) for the transverse magnetic field (X) to the main control substrate 111, but does not output either a positive or negative value for the vertical magnetic field (Z) (neither the positive nor negative threshold is reached).

[0056] When the magnet 210 rotates together with the rotating shaft 60, the state shown in Figures 8A to 8C changes to the states shown in Figures 9A to 9C. Note that Figure 9A is a schematic side view showing a state in which the magnetic encoder unit 200 detects the vertical magnetic field (Z) but not the horizontal magnetic field (X) as in Figure 7A, and the direction in which the vertical magnetic field (Z) is detected is opposite to that in Figure 7A. Figure 9B is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 9A as viewed from the front. Figure 9C is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 9A as viewed from above.

[0057] 9A to 9C differ from the states shown in Figures 7A to 7C in that the direction of the magnetic field lines in the vertical magnetic field (Z) is opposite. Therefore, in the states shown in Figures 9A to 9C, the magnetic sensor 220 outputs to the main control board 111 either a positive or negative value for the vertical magnetic field (Z), which is a value opposite in positive or negative to the state shown in Figures 7A to 7C (for example, a negative value).

[0058] 9C, for the transverse magnetic field (X), as in FIG. 7C, the magnetic field lines extend in either direction around the center line M, making it impossible for the magnetic sensor 220 to distinguish the direction of the magnetic field lines of the transverse magnetic field (X). For this reason, the transverse magnetic field (X) is not output as either a positive or negative value (it does not reach either the positive or negative threshold value).

[0059] When the magnet 210 rotates together with the rotating shaft 60, the state shown in Figures 9A to 9C changes to the state shown in Figures 10A to 10C. Note that Figure 10A is a schematic side view showing a state in which the magnetic encoder unit 200 does not detect the vertical magnetic field (Z) but detects the horizontal magnetic field (X), and the direction of detection of the horizontal magnetic field (X) is opposite to that in Figure 8A. Figure 10B is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 10A as viewed from the front. Figure 10C is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 10A as viewed from above.

[0060] The states shown in Figures 10B and 10C differ from the states shown in Figures 8A to 8C in that the direction of the magnetic field lines in the transverse magnetic field (X) is opposite. Therefore, in the states shown in Figures 10B and 10C, the magnetic sensor 220 outputs to the main control board 111 either a positive or negative value for the transverse magnetic field (X), which is a value opposite to that in the states shown in Figures 8A to 8C (for example, a negative value).

[0061] 8A, only a very weak vertical magnetic field (Z) that does not exceed the threshold value of the vertical magnetic field (Z) can be detected for the magnetic field that penetrates the magnetic sensor 220 in a direction that intersects with the sub-substrate 112, and the vertical magnetic field (Z) cannot be detected. Therefore, the vertical magnetic field (Z) is not output as either a positive or negative value (it does not reach either the positive or negative threshold value).

[0062] 11 shows the detection signals output by the magnetic sensor 220 to the main control board 111 as described above. In Fig. 11, as the rotation shaft 60 rotates, for example, with respect to (vertical magnetic field (Z), horizontal magnetic field (X)), each time the rotation shaft 60 and magnet 210 rotate by 90 degrees, detection signals are output to the main control board 111 in the following order: (positive, no detection), (no detection, positive), (negative, no detection), (no detection, negative).

[0063] In addition, when the magnetic sensor 220 is a bipolar output type capable of detecting transverse magnetic fields in two different directions, the magnetic sensor 220 may be disposed on the axis L rather than offset from the axis L. In this case, the two orthogonal transverse magnetic fields are referred to as a transverse magnetic field (X) and a transverse magnetic field (Y).

[0064] Detection of a magnetic field (change in magnetic field) in such an arrangement will be described with reference to Figures 12A to 12C and Figures 13A to 13C. Figure 12A is a schematic side view showing a state in which the magnetic encoder unit 200 detects the transverse magnetic field (Y) but not the transverse magnetic field (X). Figure 12B is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 12A as viewed from the front. Figure 12C is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 12A as viewed from above. Note that in Figures 12A and 12C, the hatched portion of the magnet 210 represents the north pole, and the white portion represents the south pole (the same applies to the other figures).

[0065] 12A to 12C, the magnetic sensor 220 can detect a magnetic field that is oriented along the sub-board 112 and penetrates the magnetic sensor 220 (the short side direction of the magnetic sensor 220) as a transverse magnetic field (Y). That is, in the state shown in FIGS. 12A to 12C, the magnetic sensor 220 outputs either a positive or negative value (for example, a positive value) for the transverse magnetic field (Y) to the main control board 111. On the other hand, the magnetic sensor 220 does not output either a positive or negative value for the transverse magnetic field (X) (it does not reach either the positive or negative threshold value).

[0066] When the magnet 210 rotates together with the rotating shaft 60, the state shown in Figures 12A to 12C changes to the state shown in Figures 13A to 13C. Note that Figure 13A is a schematic side view showing a state in which the magnetic encoder unit 200 does not detect the transverse magnetic field (Y) but does detect the transverse magnetic field (X). Figure 13B is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 13A as viewed from the front. Figure 13C is a diagram showing the magnetic encoder unit 200 in the state shown in Figure 13A as viewed from above.

[0067] 13B and 13C, the magnetic sensor 220 can detect a magnetic field that runs along the sub-board 112 and penetrates the magnetic sensor 220 (the short side of the magnetic sensor 220) as a transverse magnetic field (X). At this time, as shown in FIG. 12C, the boundary P between the north and south poles of the magnetic sensor 220 is generally aligned with the center line M of the magnetic sensor 220. Thus, in the states shown in FIGS. 13A to 13C, the magnetic sensor 220 outputs the transverse magnetic field (X) to the main control board 111 as either a positive or negative value (for example, a positive value). On the other hand, the magnetic sensor 220 does not output either a positive or negative value for the transverse magnetic field (Y) (it does not reach either the positive or negative threshold value).

[0068] 13A to 13C, the south and north poles of the magnet 210 are rotated 90 degrees together with the rotating shaft 60, which is the opposite of the state shown in FIGS. 12A to 12C (this state is not shown). In this case, the magnetic sensor 220 outputs the transverse magnetic field (Y) to the main control board 111 as a value opposite to that shown in FIGS. 12A to 12C (e.g., a negative value). On the other hand, the transverse magnetic field (X) is not output as either a positive or negative value (neither the positive nor negative threshold is reached).

[0069] Furthermore, when magnet 210 rotates 90 degrees together with rotation shaft 60 from the state shown in Figures 12A to 12C, where the south pole and north pole are in an inverted relationship (i.e., when magnet 210 rotates 180 degrees together with rotation shaft 60 from the state shown in Figures 13A to 13C), the south pole and north pole will be in an inverted relationship from the state shown in Figures 13A to 13C.

[0070] In this case, the magnetic sensor 220 outputs a positive or negative value for the transverse magnetic field (X) that is the opposite of the state shown in Figures 13A to 13C (for example, a negative value) to the main control board 111. On the other hand, the magnetic sensor 220 does not output a positive or negative value for the transverse magnetic field (Y) (it does not reach either the positive or negative threshold value).

[0071] 14 shows the detection signals output by the magnetic sensor 220 to the main control board 111 when the magnetic sensor 220 is arranged on the axis L as described above. In Fig. 14, with respect to the (transverse magnetic field (X), transverse magnetic field (Y)) accompanying the rotation of the rotation shaft 60, detection signals are output to the main control board 111 in the following order each time the rotation shaft 60 and magnet 210 rotate by 90 degrees: (no detection, positive), (positive, no detection), (no detection, negative), (negative, no detection).

[0072] <Effects> The electric chain hoist 10 configured as described above includes the motor 21, the reduction gear mechanism 80 (reduction mechanism), the brake mechanism 70, and the load sheave member 90, and transmits the driving force from the motor 21 to the load sheave member 90 via the reduction gear mechanism 80 (reduction mechanism), thereby lifting and lowering a load. The electric chain hoist 10 also includes a magnet 210 that is attached to the rotating shaft 60 that transmits the driving force from the motor 21, and whose magnetic poles change along the circumferential direction, and a magnetic sensor 220 that is arranged in a non-contact position close to the magnet 210 and detects the magnetic field of the magnet 210. The tip side of the rotating shaft 60 passes through a through hole 79 that penetrates the brake mechanism 70, and the magnet 210 is attached to the tip side of the rotating shaft 60 before the driving force of the motor 21 is reduced by the reduction gear mechanism 80 (reduction mechanism). The magnetic sensor 220 is positioned at a position offset by a predetermined distance from the axis L of the rotating shaft 60 and outputs at least two detection signals with different phases. The at least two detection signals with different phases are a detection signal of a vertical magnetic field (Z), which is a magnetic field input to the magnetic sensor 220 in a state along the axial direction (X direction), and a detection signal of a horizontal magnetic field (X), which is a magnetic field input to the magnetic sensor 220 in a state perpendicular to the vertical magnetic field (Z).

[0073] The electric chain hoist 10 configured as described above is equipped with a magnet 210 and a magnetic sensor 220 instead of an optical encoder (a magnetic encoder unit 200 composed of these is used). Here, an optical encoder is equipped with a rotating disk, but the magnet 210 and magnetic sensor 220 (magnetic encoder unit 200) are not equipped with a rotating disk. Therefore, it is not necessary to use a rotating disk that is larger in size than the magnet 210 and magnetic sensor 220, and it is possible to reduce the size of the electric chain hoist 10.

[0074] Furthermore, when the size of the rotating disk is reduced, the requirement for concentricity between the rotating disk and the rotating shaft to which it is attached increases. However, in this embodiment, since magnet 210 is attached to the tip side of rotating shaft 60 and magnetic sensor 220 is positioned at a position offset by a predetermined distance from axis L of rotating shaft 60, when attaching magnet 210 and magnetic sensor 220, the requirement for precision in attachment does not become so high compared to the above-mentioned requirement for concentricity.

[0075] Furthermore, since the speed can be detected before being reduced by the reduction gear mechanism 80 (reduction mechanism), sufficient detection accuracy can be achieved even if the resolution is lower than that of, for example, an optical encoder. Furthermore, compared to when a small optical encoder is used, the magnet 210 and magnetic sensor 220 are relatively inexpensive, making it possible to reduce manufacturing costs.

[0076] In addition, the magnetic sensor 220 outputs two detection signals with different phases, one for the vertical magnetic field (Z) and the other for the horizontal magnetic field (X), which makes it possible to increase the resolution in the direction of rotation of the rotating shaft 60 and to detect the rotation angle of the rotating shaft 60.

[0077] Furthermore, in this embodiment, the electric chain hoist 10 can also be configured as follows. That is, the electric chain hoist 10 includes a magnet 210 attached to a rotating shaft 60 that transmits driving force from the motor 21 and whose magnetic polarity changes along the circumferential direction, and a magnetic sensor 220 that is disposed close to the magnet 210 but not in contact with it and detects the magnetic field of the magnet 210. The tip side of the rotating shaft 60 passes through a through-hole 79 that penetrates the brake mechanism 70, and the magnet 210 is attached to the tip side of the rotating shaft 60 before the driving force of the motor 21 is reduced by a reduction gear mechanism 80 (reduction mechanism). The magnetic sensor 220 is disposed on the axis L of the rotating shaft 60 and outputs at least two detection signals with different phases, and the at least two detection signals with different phases are detection signals of a transverse magnetic field (X, Y), which is a magnetic field that is input to the magnetic sensor 220 in a state perpendicular to the axial direction of the rotating shaft 60.

[0078] The electric chain hoist 10 configured in this manner also includes a magnet 210 and a magnetic sensor 220 instead of an optical encoder (a magnetic encoder unit 200 configured from these is used). Here, an optical encoder includes a rotating disk, but the magnet 210 and magnetic sensor 220 (magnetic encoder unit 200) do not include a rotating disk. Therefore, there is no need to use a rotating disk that is larger in size than the magnet 210 and magnetic sensor 220, and the electric chain hoist 10 can be made smaller.

[0079] Furthermore, since the speed can be detected before being reduced by the reduction gear mechanism 80 (reduction mechanism), sufficient detection accuracy can be achieved even if the resolution is lower than that of, for example, an optical encoder. Furthermore, compared to when a small optical encoder is used, the magnet 210 and magnetic sensor 220 are relatively inexpensive, making it possible to reduce manufacturing costs.

[0080] Furthermore, the magnetic sensor 220 outputs two detection signals with different phases, one for the transverse magnetic field (X) and the other for the transverse magnetic field (Y), which makes it possible to increase the resolution in the direction of rotation of the rotating shaft 60 and to detect the rotation angle of the rotating shaft 60.

[0081] In this embodiment, the magnetic sensor 220 can be of a bipolar output type that can detect magnetic fields in two different directions.

[0082] In this configuration, the magnetic sensor 220 is a bipolar output type that can detect magnetic fields in two different directions, so it is possible to detect not only the rotation angle but also the direction of rotation.

[0083] In addition, in this embodiment, the magnetic sensor 220 is attached to a sub-board 112 that is different from the main control board 111 that controls the motor 21, and the sub-board 112 is attached in a state that blocks the opening of the through-hole 79 that passes through the fixed part of the brake mechanism 70 that stops the rotation of the rotating shaft 60, and faces the magnet 210 on the side opposite to the side on which the magnetic sensor 220 is mounted.

[0084] In this way, by separating the sub-board 112 on which the magnetic sensor 220 is mounted from the main control board 111, the sub-board 112 can be mounted independently of the main control board 111, for example, on the end face of the brake mechanism 70 on one side (X2 side) in the axial direction (X direction). This facilitates positioning of the sub-board 112, shortening the distance to the magnet 210 and improving the detection accuracy of the magnetic sensor 220. Furthermore, by mounting the sub-board 112 on which the magnetic sensor 220 is mounted so as to cover the opening of the through-hole 79, it is possible to prevent wear powder generated by the brake mechanism 70 from scattering around. Furthermore, because the sub-board 112 faces the magnet 210 on the side opposite to the surface on which the magnetic sensor 220 is mounted, it is possible to prevent wear powder from adhering to the magnetic sensor 220 and prevent a decrease in the detection accuracy of the magnetic sensor 220. Note that magnetic fields pass through the sub-board 112 and are detected by the magnetic sensor 220.

[0085] In addition, in this embodiment, the brake mechanism 70 includes a stator 71 and an armature 73 that forms a magnetic circuit together with the stator 71, and the sub-substrate 112 is attached to the side of the stator 71 opposite to the side on which the armature 73 is arranged.

[0086] When configured in this manner, the sub-board 112 on which the magnetic sensor 220 is mounted can be separated from the magnetic circuit consisting of the stator 71 and the armature 73, thereby reducing the influence of the coil 72 on the magnetic sensor 220.

[0087] <Modifications> Although the embodiments of the present invention have been described above, the present invention can be modified in various other ways, which will be described below.

[0088] In the above-described embodiment, the magnetic sensor 220 can be configured to be attached to the main control board 111 that controls the motor 21. By attaching the magnetic sensor 220 to the main control board 111 in this way, the number of parts can be reduced, and costs can be reduced accordingly.

[0089] In the above embodiment, the magnetic sensor 220 outputs two detection signals, but it may be configured to output three or more detection signals. For example, the magnetic sensor may be configured to detect a magnetic field (horizontal magnetic field) that is orthogonal to both the vertical magnetic field and the horizontal magnetic field. Furthermore, the magnetic sensor may be configured to output only a single magnetic field.

[0090] In the above embodiment, the magnet 210 is made of neodymium. However, the magnet may be made of a material other than neodymium. For example, various magnets such as ferrite magnets, alnico magnets, KS steel, MK steel, rare earth magnets, etc. may be used.

[0091] 10...electric chain block, 20...motor unit, 21...motor, 22...stator, 23...rotor, 23a...center hole, 30...motor shaft, 40...friction clutch mechanism, 41...friction disc, 42...sliding disc, 42a...flange portion, 43...spring receiving member, 44...biasing spring, 50...body, 51...motor holder, 52...cover, 60...rotating shaft, 61...gear portion, 62...recess, 70...brake mechanism, 71...stator, 72...coil, 73...armature, 74...support shaft, 75...attachment Moment spring, 76...plate, 77...rotor, 78...rotor hub, 79...through hole, 80...reduction gear mechanism (corresponding to reduction mechanism), 81...first driven gear, 82...load gear, 90...load sheave member, 100...hook, 110...control unit, 111...main control board, 112...sub-board, 200...magnetic encoder unit, 210...magnet, 220...magnetic sensor, B1...bearing, B2...bearing, B3...bearing, C1...coupling, X, Y...horizontal magnetic field, L...axis line, M...center line, P...boundary line, Z...vertical magnetic field

Claims

1. An electric chain block comprising a motor, a reduction gear mechanism, a brake mechanism, and a load sheave, and for raising and lowering a load by transmitting driving force from the motor to the load sheave via the reduction gear mechanism, comprising: a magnet attached to a rotating shaft that transmits the driving force from the motor, and whose magnetic poles change along the circumferential direction; and a magnetic sensor arranged in a non-contact manner in the vicinity of the magnet and for detecting the magnetic field of the magnet, wherein the tip side of the rotating shaft passes through a through hole that penetrates the brake mechanism, the magnet is attached to the tip side of the rotating shaft before the driving force of the motor is reduced by the reduction gear mechanism, the magnetic sensor is arranged at a position offset a predetermined distance from the axis of the rotating shaft, and outputs at least two detection signals of different phases, the at least two detection signals of different phases being a detection signal of a vertical magnetic field (Z), which is a magnetic field input to the magnetic sensor in a state along the axial direction of the rotating shaft, and a detection signal of a horizontal magnetic field (X), which is a magnetic field input to the magnetic sensor in a state perpendicular to the vertical magnetic field.

2. An electric chain block comprising a motor, a reduction gear mechanism, a brake mechanism and a load sheave, and for raising and lowering a load by transmitting the driving force from the motor to the load sheave via the reduction gear mechanism, comprising: a magnet attached to a rotating shaft that transmits the driving force from the motor, and whose magnetic poles change along the circumferential direction; and a magnetic sensor arranged in a non-contact manner in the vicinity of the magnet and for detecting the magnetic field of the magnet, wherein the tip side of the rotating shaft passes through a through hole that penetrates the brake mechanism, the magnet is attached to the tip side of the rotating shaft before the driving force of the motor is reduced by the reduction gear mechanism, the magnetic sensor is arranged on the axis of the rotating shaft and outputs at least two detection signals with different phases, and the at least two detection signals with different phases are detection signals of a transverse magnetic field (X, Y), which is a magnetic field input to the magnetic sensor in a state perpendicular to the axial direction of the rotating shaft.

3. An electric chain block according to claim 1 or 2, characterized in that the magnetic sensor is a bipolar output type capable of detecting magnetic fields in two different directions.

4. An electric chain block as claimed in claim 1 or 2, characterized in that the magnetic sensor is attached to a sub-board different from a main control board which controls the motor, the sub-board is attached in a manner that covers the opening of a through hole which passes through a fixed portion of the brake mechanism which stops the rotation of the rotating shaft, and the sub-board faces the magnet on the side opposite to the side on which the magnetic sensor is mounted.

5. An electric chain block as claimed in claim 4, wherein the brake mechanism comprises a stator and an armature which forms a magnetic circuit together with the stator, and the sub-board is attached to the surface of the stator opposite to the side on which the armature is arranged.

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