Lifting mechanism

Abstract

To provide a lifting mechanism capable of reducing the output of a motor.SOLUTION: This lifting mechanism 1 for lifting the object threadedly engaged with a ball screw 3 by rotating the ball screw 3 by rotation of a motor 2, includes a spiral spring 42 for imparting torque in the direction of lifting the object to the ball screw 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lifting mechanism for lifting a sonar or the like. [Background technology]

[0002] For example, as a lifting mechanism for raising and lowering a sonar from the bottom of a ship into the sea, a mechanism that converts the rotational motion of a motor into linear motion using a ball screw has been known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7269666 Summary of the Invention [Problem to be solved by the invention]

[0004] However, some sonars are large and weigh several hundred kilograms, and with conventional lifting mechanisms, the motor output and capacity must be increased to match the weight of the sonar, which not only increases costs but also can make installation and handling difficult.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a lifting mechanism that allows the output of the motor to be reduced. [Means for solving the problem]

[0006] In order to achieve the above object, the invention described in claim 1 is a lifting mechanism that rotates a ball screw by rotation of a motor to lift an object threaded onto the ball screw, and is characterized by having a spiral spring that imparts a rotational force to the ball screw in a direction to lift the object.

[0007] The invention described in claim 2 is characterized in that, in the lifting mechanism described in claim 1, the spiral spring is arranged so that the rotational force is maximized when the object is positioned at bottom dead center. [Effects of the Invention]

[0008] According to the invention of claim 1, the spiral spring applies a rotational force to the ball screw in a direction that lifts an object, making it possible to reduce the motor output. In other words, when lifting an object, it is possible to reduce the output and capacity required of the motor by the rotational force of the spiral spring. Furthermore, while there was a conventional risk of the object falling when the motor brake was released, it is now possible to prevent the object from falling by using the rotational force of the spiral spring.

[0009] According to the invention described in claim 2, the spiral spring is arranged so that the rotational force is maximized when the object is at the bottom dead center (lowest position), which makes it possible to reduce the motor output. In other words, when an object is raised from the bottom dead center, the maximum rotational force acts on the ball screw at the beginning of the rise, making it possible to reduce the output and capacity required of the motor. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a conceptual diagram showing a lifting mechanism according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described below based on the illustrated embodiments.

[0012] 1 is a conceptual diagram showing an elevating mechanism 1 according to an embodiment of the present invention. This elevating mechanism 1 is a mechanism that rotates a ball screw 3 by the rotation of a motor 2, thereby elevating an object threadedly engaged with the ball screw 3, and utilizes the power of a spiral spring 42 in addition to the power of the motor 2.

[0013] In this embodiment, the case where the object to be raised and lowered is a sonar S will be described, and the sonar S will be raised and lowered in a direction approximately vertical to the bottom of the ship into the sea. However, the lifting mechanism 1 can also be applied to cases where an object other than the sonar S is raised and lowered.

[0014] In this lifting mechanism 1, first, a motor-side gear 22 is disposed on the output shaft 21 of the motor 2, and a first screw-side gear 31 is disposed on one end side and the upper end side of the ball screw 3, with the motor-side gear 22 meshing with the first screw-side gear 31. As a result, when the motor 2 starts and the output shaft 21 and the motor-side gear 22 rotate, the first screw-side gear 31 rotates, and accordingly the ball screw 3 rotates.

[0015] On the other hand, the sonar S is a device that transmits sound waves underwater to acquire information about targets and objects in the water or on the bottom of the water, and a main body (not shown) transmits and receives the sound waves, and a nut S1 is provided on top of the main body. The nut S1 of the sonar S is screwed into the center of the ball screw 3.

[0016] That is, the nut part S1 has a structure similar to that of a ready-made, existing ball screw nut, with a groove formed in a spiral shape on the inner peripheral surface of the hole through which the ball screw 3 passes, and a ball is attached and fitted between this groove and the spiral groove formed in the ball screw 3, thereby threading the nut part S1 onto the ball screw 3. Meanwhile, the sonar S is supported by a linear guide (not shown) so that it can move up and down without rotating, and as the ball screw 3 rotates, the sonar S rises and falls along the ball screw 3.

[0017] Here, when the ball screw 3 rotates in one direction (for example, clockwise), the sonar S rises, and when the ball screw 3 rotates in the other direction (for example, counterclockwise), the sonar S falls. For this reason, in this embodiment, the motor 2 is rotatable in both the left and right directions (forward and reverse directions). For example, when the motor 2 rotates counterclockwise, the ball screw 3 rotates in one direction and the sonar S rises, and when the motor 2 rotates clockwise, the ball screw 3 rotates in the other direction and the sonar S falls.

[0018] This basic mechanism is equipped with a spring device 4 that applies a rotational force to the ball screw 3 in a direction that raises the sonar S. First, a second screw side gear 32 is disposed on the side of the first screw side gear 31 of the ball screw 3.

[0019] The spring device 4 mainly includes a rotating shaft 41, a spiral spring 42, a spiral side gear 43, and a case 44 that houses the spiral spring 42.

[0020] The case 44 is a box-shaped case with an open top, and is fixed to and disposed in a casing or the like that houses the lifting mechanism 1. The lower end of the rotating shaft 41 is rotatably attached to the case 44, and extends parallel to the ball screw 3.

[0021] The power spring 42 is a spring made of a highly elastic metal plate (strip) wound in a spiral shape, and one end is fixed to the inner surface of the case 44 and the other end is fixed to the lower part of the rotating shaft 41. The power spring side gear 43 is a gear disposed and fixed to the upper end of the rotating shaft 41, and is in mesh with the second screw side gear 32.

[0022] When the ball screw 3 and second screw side gear 32 rotate in one direction and sonar S rises, the spring side gear 43 and rotating shaft 41 rotate in the other direction, and the spiral spring 42 is unwound (released). At this time, the force released from the spiral spring 42 is applied to and acts on the ball screw 3 via the spring side gear 43 and second screw side gear 32 as a rotational force in a direction (one direction) that raises sonar S. On the other hand, when the ball screw 3 and second screw side gear 32 rotate in the other direction and sonar S falls, the spring side gear 43 and rotating shaft 41 rotate in one direction, and the spiral spring 42 is wound up (force / energy is stored).

[0023] Furthermore, in this embodiment, the spiral spring 42 is disposed so that a rotational force in a direction that raises the sonar S is always applied to the ball screw 3, and the rotational force is maximized when the sonar S is at its bottom dead center or lowest position. In other words, when the sonar S descends to its bottom dead center, the spiral spring 42 is wound to its maximum extent, and when the sonar S begins to rise, the release force and rotational force from the spiral spring 42 are maximized. Furthermore, even when the sonar S rises to its top dead center or highest position, the spiral spring 42 remains in a slightly wound state (not completely unwound), and the rotational force of the spiral spring 42 remains, so that a rotational force in a direction that raises the sonar S acts on the ball screw 3.

[0024] With the lifting mechanism 1 configured as described above, a rotational force in a direction that lifts the sonar S is applied to the ball screw 3 by the spiral spring 42, making it possible to reduce the output of the motor 2. In other words, when lifting the sonar S, it is possible to reduce the output and capacity required of the motor 2 by the amount of the rotational force of the spiral spring 42.

[0025] Moreover, because the spiral spring 42 is arranged so that the rotational force is maximized when the sonar S is at the bottom dead center (lowest position), it is possible to further reduce the output of the motor 2. In other words, when the sonar S is raised from the bottom dead center position, the maximum rotational force acts on the ball screw 3 at the beginning of the ascent, making it possible to further reduce the output and capacity required of the motor 2.

[0026] Incidentally, in a conventional lifting mechanism that does not include the spiral spring 42, the output of the motor 2 when the sonar S is ascending is, for example, about 20% higher than when it is descending. On the other hand, in the present lifting mechanism 1, the spiral spring 42 must be wound when descending, so the output of the motor 2 when descending is higher than in the conventional mechanism. In contrast, when ascending, as described above, the rotational force of the spiral spring 42 causes the output of the motor 2 to be lower than in the conventional mechanism.

[0027] Therefore, for example, by increasing the output of motor 2 by 10% compared to conventional output when descending and decreasing the output of motor 2 by 10% compared to conventional output when ascending, it is possible to reduce the output and capacity required for motor 2 by 10% compared to conventional output. In other words, this lifting mechanism 1 stores force and energy in spiral spring 42 when descending and the output of motor 2 is low, and uses the force and energy stored in spiral spring 42 when ascending and the output of motor 2 is high, thereby reducing the output and capacity required for motor 2.

[0028] Meanwhile, in the past, when the motor 2 is equipped with a motor brake and the motor brake is released, there was a risk that the sonar S would fall, but it is possible to prevent the sonar S from falling by the rotational force of the spiral spring 42 in the direction that raises the sonar S. Moreover, in this embodiment, the rotational force of the spiral spring 42 is always applied to and acts on the ball screw 3 while the sonar S is moving from the bottom dead center to the top dead center, so it is possible to prevent the sonar S from falling no matter what position it is in (even if it is located at the top dead center).

[0029] Furthermore, conventional motor brakes are designed to press the brake pads (brake linings) against the brake hub, so over long periods of use the brake pads become worn and damaged, requiring maintenance. However, by using the spiral spring 42 to help prevent the pads from falling off, it is possible to reduce the frequency of brake pad maintenance and extend the life of the brake pads.

[0030] Although the embodiments of the present invention have been described above, the specific configuration is not limited to the above embodiments, and the present invention also includes design changes that do not deviate from the gist of the present invention. For example, in the above embodiments, the rotation of the motor 2 is transmitted to the ball screw 3 via the motor-side gear 22 and the first screw-side gear 31, but other transmission mechanisms are also possible. For example, the rotation of the motor 2 may be transmitted to the ball screw 3 via a belt or chain.

[0031] Furthermore, in the above embodiment, the sonar S is arranged so that the rotational force of the spiral spring 42 is maximized when it reaches the bottom dead center, but the sonar S may also be arranged so that the rotational force of the spiral spring 42 is maximized when it reaches the top dead center, with the main effect being to prevent the sonar S from falling.

[0032] Furthermore, in the above embodiment, the spiral spring 42 is disposed away from the motor 2 and the ball screw 3, and the rotational force of the spiral spring 42 is imparted to the ball screw 3 via the spiral-side gear 43 and the second screw-side gear 32, but the position and structure of the spiral spring 42 are not limited to this. For example, the spiral spring 42 may be disposed on the output shaft 21 side of the motor 2 or the motor-side gear 22 side. [Explanation of symbols]

[0033] 1 Lifting mechanism 2 motors 22 Motor side gear 3 Ball screw 31 First screw side gear 32 Second screw side gear 4 Mainspring mechanism 41 Rotation axis 42 Mainspring 43 Mainspring side gear 44 cases S Sonar (Object) S1 Nut

Claims

1. An elevator mechanism that rotates a ball screw by rotation of a motor to raise and lower an object screwed onto the ball screw, a power spring that applies a rotational force to the ball screw in a direction that lifts the object; A lifting mechanism characterized by:

2. The spiral spring is arranged so that the rotational force is maximized when the object is positioned at the bottom dead center.

2. The lifting mechanism according to claim 1.

Images