JP7464365B2 - Lead wire extraction structure for motor with additional parts - Google Patents

Description

The present invention relates to a lead wire extraction structure for a motor with additional parts.

Patent document 1 discloses a cable fixing device for holding cables used for supplying excitation current and transmitting signals in a small electric motor fixedly around the cable outlet of the electric motor housing. As shown in FIG. 2 of the same document, this cable fixing device is used to hold cables for current supply and signal transmission fixedly around the cable outlet. Furthermore, as shown in FIG. 7 of the same document, the cable fixing device is described as being able to provide a protuberance on the edge of the cable outlet side of the clamp member lid and to provide a corresponding protuberance in the area of the housing facing the protuberance. It is disclosed that these protuberances further strengthen the cable fixing action when the clamp member is placed in the clamping position. In addition, as shown in FIG. 5 of the same document, the cable fixing device is described as being able to provide a waterproof adhesive 54 around the cable outlet of the housing to provide at least a watertight seal between the cable outlet and the cable.

Patent document 2 describes a lead wire pull-out structure for pulling two types of lead wires of different thicknesses from an electrical device to the outside of the device, in which multiple thin lead wires are twisted together in a predetermined twisting section, and the twisted thin lead wires are tied to a thick lead wire at least in two places before and after the twisting section and pulled out.

Japanese Patent Application Laid-Open No. 8-182151 JP 2002-112482 A

When multiple cables (for example, a current supply cable for an electric motor and a cable for transmitting signals) are fixed by separate cable fixing devices, the cables fixed by one cable fixing device may interfere with another cable fixing device. When additional components such as sensors are attached to the motor, the cables of the additional components may also interfere with the fixing device for the motor cable.

In addition, the task of bundling multiple twisted thin lead wires into thick lead wires at two points, before and after the twisted section, can be cumbersome, especially when multiple additional parts are attached to the motor.

In view of these problems, the present invention aims to efficiently secure the lead wires of a motor and additional parts in a motor with additional parts.

In the lead wire pull-out structure for a motor with an add-on part according to the present invention, at least one additional part is attached in the direction of the rotation axis of the motor, the lead wires of the motor are pulled out from inside the housing of the motor to the outside and further pulled out in one axial direction, and the lead wires of the additional part are pulled out from inside the housing of the additional part to the outside and further pulled out in the one axial direction. Clamps are attached to the top surfaces of the housing of the motor and the housing of the additional part, and each clamp secures a lead wire pulled out from inside the housing in which the clamp is provided through the top surface of the housing to the outside and a lead wire pulled out from inside a housing attached to the other axial side of the housing in which the clamp is provided through the top surface of the housing to the outside.

According to the present invention, the lead wires of the motor and the additional parts can be efficiently fixed in a motor with additional parts.

FIG. 13 is an explanatory diagram showing a lead wire fixed by a clamp. FIG. 2 is a side view of the motor with additional parts in the first embodiment. FIG. 1 is a perspective view of a motor with additional parts according to a first embodiment. FIG. 2 is an enlarged view of the clamp and the lead wire. FIG. 13 is another enlarged view of the clamp and lead wires. FIG. 13 is yet another enlarged view of the clamp and lead wires. FIG. 11 is a perspective view of a motor with additional parts according to a second embodiment.

The inventors of the present invention have conducted extensive research into the issues surrounding the use of clamps to secure lead wires, as described below.

Figure 1 shows the claw portion 120 of the clamp attached to the upper surface 105 of the sensor housing. The claw portion 120 secures the sensor lead wire 110 that is pulled out from inside the sensor housing to the outside. Since the lead wire 110 is secured by the claw portion 120, a certain degree of securing strength against pulling of the lead wire 110 (securing strength in a direction parallel to the pull-out direction Y0) can be obtained. However, the securing strength in the left-right direction (direction indicated by arrow Y1) based on the pull-out direction is not sufficient. In other words, the claw portion 120 may act as a fulcrum and cause the lead wire 110 to move left-right based on the pull-out direction. If the lead wire 110 moves left-right, there is a problem that stress is applied to the connection portion (not shown) between the sensor body and the lead wire 110 inside the sensor housing.

When the lead wire 110 is a lead wire coated with a fluororesin-based material, the coating has a low coefficient of friction, making the lead wire 110 slippery, and the coating is hard, making it difficult for the claw portion 120 to bite into the coating. Therefore, when the lead wire is coated with a fluororesin-based material, the above-mentioned problem of movement in the left-right direction is prominent.

The above problem applies not only to sensor lead wires, but to all lead wires that are secured by clamps.

An embodiment of the present invention based on the above study results will be described below. However, the present invention is not limited to the following embodiment. In the figure, arrow A1 indicates the output axis direction of the motor, and arrow A2 indicates the counter-output axis direction (the direction opposite to the output axis direction of the motor). The output axis direction and the counter-output axis direction are collectively referred to as the rotation axis direction.

[First embodiment]
2 and 3 show a motor with additional parts 20 according to this embodiment. The motor with additional parts 20 includes a motor 7 having an output shaft 7a, and a sensor 1 and a brake 4 which are additional parts of the motor. The sensor 1 detects the rotation of the motor 7, and the brake 4 brakes the rotation of the motor 7 and provides a holding torque when the motor is stopped. The brake 4 is attached to the opposite output shaft side of the motor 7, and the sensor 1 is attached to the opposite output shaft side of the brake 4.

A sensor wire clamp 3 is provided on the top surface of the housing of the sensor 1 to secure the sensor lead wire 2 that is pulled out from inside the housing of the sensor 1 to the outside. The sensor lead wire 2 is pulled out from the sensor wire clamp 3 in the output shaft direction.

A brake line clamp 6 is provided on the top surface of the housing of the brake 4. The brake line clamp 6 secures the brake lead wire 5, which is pulled out from inside the housing of the brake 4 to the outside, and the sensor lead wire 2, which is pulled out from the sensor line clamp 3 in the output shaft direction. The brake lead wire 5 and the sensor lead wire 2 are pulled out from the brake line clamp 6 in the output shaft direction.

A motor line clamp 9 is provided on the top surface of the housing of the motor 7. The motor line clamp 9 secures the motor lead wire 8, which is pulled out from inside the housing of the motor 7 to the outside, and the brake lead wire 5 and sensor lead wire 2, which are pulled out in the output shaft direction from the brake line clamp 6. The motor lead wire 8, brake lead wire 5, and sensor lead wire 2 are pulled out in the output shaft direction from the motor line clamp 9 and connected to a single connector 11 as an output lead wire group 10. The connector 11 is connected to a drive device (not shown) that drives the motor 20 with additional parts.

Examples of lead dimensions and lead clamp dimensions are as follows. Clamp dimensions are the dimension from the clamp tab to the housing surface to which the clamp is attached. Note that in the following examples, the brake lead dimensions are the same as the motor lead dimensions.
<Example of lead wire dimensions>
・Motor lead wire 8 AWG22 (lead wire coating outer diameter φ1.4mm)
・Brake lead wire 5 AWG22 (lead wire coating outer diameter φ1.4mm)
・Sensor lead wire 2 AWG26 (lead wire coating outer diameter φ1.1mm)
<Example of clamp dimensions>
・Motor lead wire 8 clamp dimension 1.0 mm
・Clamp dimension of brake lead wire 5: 1.0 mm
・Clamp dimension of sensor lead wire 2: 0.7 mm

According to this embodiment, first, the sensor lead wire 2 is fixed by the sensor wire clamp 3. Next, the sensor lead wire 2 is fixed together with the brake lead wire 5 by the brake wire clamp 6. Next, the sensor lead wire 2 is fixed together with the brake lead wire 5 and the motor lead wire 8 by the motor wire clamp 9.

In other words, the sensor lead wire 2, which has the smallest outer diameter of the three types of lead wires, is fixed by multiple clamps, namely the sensor wire clamp 3, the brake wire clamp 6, and the motor wire clamp 9. Furthermore, the sensor lead wire 2 is fixed by clamps 6 and 9 together with another type of lead wire that has a larger outer diameter than the sensor lead wire. This reduces the possibility that the sensor lead wire 2 will move on the top surface of the sensor housing with the sensor wire clamp 3 as a fulcrum. As a result, stress on the internal connection part of the sensor lead wire 2 (the connection part with the sensor main body inside the housing of the sensor 1) is suppressed.

The brake lead wire 5, together with other types of lead wires, is fixed by multiple clamps, namely the brake line clamp 6 and the motor line clamp 9. This reduces the possibility that the brake lead wire 5 will move on the top surface of the brake housing with the brake line clamp 6 as a fulcrum. As a result, stress on the internal connection part of the brake lead wire 5 (the connection part with the brake main body part inside the housing of the brake 4) is reduced.

The motor lead wire 8 is secured together with the other types of lead wires 2 and 5 by a single clamp, i.e., the motor line clamp 9. This reduces the possibility that the motor lead wire 8 will move on the top surface of the motor housing with the motor line clamp 9 as a fulcrum, compared to when the motor lead wire is secured alone rather than together with the other leads. As a result, stress on the internal connection of the motor lead wire 8 (the connection with the motor body inside the housing of the motor 7) is reduced.

In this way, the sensor lead 2, brake lead 5, and motor lead 8 are all fixed together by at least one clamp, reducing the possibility of each lead moving on the top surface of each housing compared to when each lead is fixed separately. As a result, stress on the internal connection of each lead is reduced.

The brake lead wire 5 is secured by two clamps, and the sensor lead wire 2 is secured by three clamps, further reducing stress on the internal connections of these leads.

In addition, an output lead wire clamp 12 that secures the output lead wire group 10 may be provided on the upper surface of the housing of the motor 7, spaced apart from the motor wire clamp 9 in the output axial direction (Figure 3). This can further reduce stress on the internal connections of the motor lead wires 8.

In Figures 2 and 3, the brake and sensor are attached in that order to the side opposite the output shaft of the motor, but the order of the brake and sensor may be reversed. Alternatively, only one of the brake and the sensor may be attached to the motor. Additional parts other than the brake and the sensor may be attached to the motor. Furthermore, additional parts may be attached to the output shaft side of the motor. In other words, it is sufficient that the additional parts are attached to the motor in the direction of the rotation axis of the motor.

To reduce the effects of noise, the multiple motor leads can be twisted pair wired. Also, the leads of at least one additional component can be twisted pair wired for each additional component. If the additional components are a brake and a sensor, the multiple brake leads can be twisted pair wired, and the multiple sensor leads can also be twisted pair wired.

The height of the dead space at the top of the housing is equal to the maximum height dimension H among the multiple clamps (Figure 2). The height H of the dead space is smaller than when the lead wires or cables are pulled out above the clamp. This reduces the height of the dead space at the top of the housing, making it easier to design in a space-saving manner. It is also possible to provide a drive unit (not shown) for a motor with additional parts at the top of the housing.

Figures 4 to 6 show examples of clamps that can be used when there is a difference in the outer diameter or dimensional error of the lead wire to be fixed. The clamp strength depends on the difference between the outer diameter of the lead wire and the height of the clamp jaws (tightening margin). On the other hand, since both the clamp and the lead wire coating are generally manufactured by molding, it is difficult to achieve dimensional accuracy. Therefore, it is difficult to maintain clamp strength while avoiding the risk of lead wire breakage due to overtightening, and repeated prototyping is necessary to determine the design value of the clamp strength. In addition, the outer diameter of the selected lead wire may change depending on the motor output, and it becomes even more difficult to use a common clamp regardless of the outer diameter. To deal with such cases, slits are provided in the clamp to facilitate elastic deformation as described below, which can absorb dimensional errors and differences due to different lead wires.

Examples of clamp materials include polybutylene terephthalate (PBT) resin, nylon, and elastomer.

Figure 4 shows the motor line clamp 9 attached to the top surface of the motor housing, and the sensor lead wire 2 and motor lead wire 8 fixed by the motor line clamp. Note that the brake lead wire 5 is not shown. The clamp 9 has two slits 91 formed parallel to the pull-out direction from one end face of the lead wire to be fixed. This forms a lead wire fixing part 92 of the clamp 9 so that it is sandwiched between the two slits 91. The lead wire fixing part 92 is movable in the direction indicated by the arrow Y2 due to elastic deformation of the clamp 9 with the slits 91. A claw part 93 that protrudes downward is formed on the bottom surface of the lead wire fixing part 92. The lead wire to be fixed is fixed by the claw part 93.

Because the lead wire fixing portion 92 is movable, it is possible to absorb the outer diameter difference and dimensional error between the multiple lead wires to be fixed.

[Second embodiment]
7, it is also possible to pull out each lead wire in the counter-output shaft direction. That is, the motor lead wire 8 is fixed by a motor wire clamp 9. The motor lead wire 8 is pulled out from the motor wire clamp 9 in the counter-output shaft direction.

The brake lead wire 5 and the motor lead wire 8 are fixed by the brake line clamp 6. The brake lead wire 5 and the motor lead wire 8 are pulled out from the brake line clamp 6 in the direction opposite the output shaft.

The sensor lead wire 2, brake lead wire 5, and motor lead wire 8 are fixed by the sensor wire clamp 3. The sensor lead wire 2, brake lead wire 5, and motor lead wire 8 are pulled out from the sensor wire clamp 3 in the counter-output shaft direction as the output lead wire group 10.

This embodiment also reduces stress on the internal connections of each lead wire. An output lead wire clamp 12a for fixing the output lead wire group 10 may be provided on the upper surface of the housing of the sensor 1, spaced apart from the sensor wire clamp 3 in the counter-output axial direction. This further reduces stress on the internal connections of the sensor lead wires 2.

The motor 7 in the first and second embodiments described above is used in applications that require highly accurate position control and speed control. In order to perform accurate speed and position control, sensors such as an encoder and a Hall element are required outside the motor. In addition, if the driven object attached to the output shaft of the motor 7 moves in the vertical direction, an electromagnetic brake must be provided as a measure to prevent it from falling in the event of a power outage.

Encoders, a type of sensor, generally have detection methods such as optical and magnetic, but both methods require a combination of multiple signal lines and a power line required to generate the signal. Furthermore, when installing a sensor or electromagnetic brake in the axial direction of a motor, it is necessary to make the sensor and electromagnetic brake small in order to shorten the axial length. In a structure in which a board and multiple lead wires are connected in a limited space, stress caused by the movement of the lead wires is applied directly to the connection part of the board, which can cause the connection part of the sensor wire and the board to break. For these reasons, traditionally, cables rather than lead wires are used as sensor lead wires, and the cable itself is clamped to prevent breakage.

In addition, there has been a recent trend towards higher speeds for motors used in position control and speed control, and to achieve this, it is necessary to pass a large current through the motor. On the other hand, passing a large current increases motor loss, and in order to minimize this loss, it is necessary to use thick lead wires for the conductor section. This is the reason why there is a difference in the outer diameter between the motor wire and the sensor wire.

When installing a motor for position control or speed control that uses a cable, the bending radius of the cable must be equal to or greater than the recommended bending radius for that cable. If the cable is installed with a bending radius less than the recommended value, the cable's insulation may be damaged or the cable's core wire may break, causing the motor to malfunction. For this reason, when used in robots that have limited installation space, there is a need for the lead wires of the motor and additional parts to have a recommended bending radius smaller than that of the cable. The first and second embodiments described above address this need.

In the lead wire pull-out structure of the motor with an add-on part based on the above-mentioned first and second embodiments, first, at least one add-on part is attached in the direction of the rotation axis of the motor. The lead wires of the motor are pulled out from inside the housing of the motor to the outside, and are further pulled out in one axial direction. The lead wires of the add-on part are pulled out from inside the housing of the add-on part to the outside, and are further pulled out in the one axial direction. Clamps are provided on both the motor housing and the housing of the add-on part. Each clamp secures the lead wire pulled out from inside the housing in which the clamp is provided to the outside, and the lead wire pulled out from inside the housing attached to the other axial side of the housing in which the clamp is provided to the outside.

Although the embodiment of the present invention has been described above, the present invention is not limited to the embodiment described above, and various modifications and changes are possible based on the technical concept of the present invention.

REFERENCE SIGNS LIST 1 sensor, 2 sensor lead wire, 3 sensor wire clamp 4 brake, 5 brake lead wire, 6 brake wire clamp 7 motor, 7a output shaft, 8 motor lead wire, 9 motor wire clamp 10 output lead wire group, 11 connector 20 motor with additional parts 91 slit, 92 moving part, 93 claw part

Claims (8)

A lead wire extraction structure for a motor with an additional part,
At least one of the additional parts is attached in the direction of the rotation axis of the motor,
a lead wire of the motor is drawn from inside the housing of the motor to the outside and further drawn in one axial direction, and a lead wire of the additional part is drawn from inside the housing of the additional part to the outside and further drawn in one axial direction,
a clamp is attached to each of an upper surface of the housing of the motor and an upper surface of the housing of the additional part, and each clamp fixes a lead wire drawn from inside the housing in which the clamp is provided to the outside through the upper surface of the housing , and a lead wire drawn from inside a housing attached to the other axial side of the housing in which the clamp is provided to the outside through the upper surface of the housing ;
Lead wire extraction structure for motors with additional parts. The lead wire extraction structure of a motor with an additional part according to claim 1, wherein the at least one additional part is either or both of a brake that brakes the rotation of the motor and a sensor that detects the rotation of the motor. 3. The lead wire extraction structure of a motor with an additional part as described in claim 1 or 2, wherein all of the lead wires extracted in one axial direction are connected to a single connector located outside the housing of the motor and outside the housing of the additional part. The lead wire extraction structure of a motor with additional parts according to any one of claims 1 to 3, wherein the multiple lead wires of the motor are twisted pair wiring, and for each of the at least one additional part, the multiple lead wires of the additional part are twisted pair wiring. The lead wire pull-out structure of a motor with additional parts according to any one of claims 1 to 4, wherein the clamp has two slits formed parallel to the pull-out direction from one end face of the lead wire to be fixed in the pull-out direction. The lead wire pull-out structure of a motor with an additional part according to claim 5, wherein a claw portion for fixing the lead wire to be fixed is formed on the bottom surface of the lead wire fixing portion of the clamp sandwiched between the two slits. The lead wire pull-out structure of a motor with an additional part according to any one of claims 1 to 6, wherein the lead wire of the at least one additional part has an outer diameter smaller than the lead wire of the motor. A lead wire extraction structure for a motor with additional parts as described in any one of claims 1 to 7, further comprising a further clamp that secures all of the lead wires extracted in the one axial direction from a clamp that is located furthest on the one axial direction side of the plurality of clamps, the further clamp being attached to an upper surface of the housing that is located furthest on the one axial direction side .