Cable guide member and electric motor

Abstract

This cable guide member can be attached to a housing of an electric motor and a flexible cable containing one or more lead wires for performing drive control on the electric motor can be inserted into the cable guide member. The cable guide member comprises: an insertion part for inserting the cable; and an attachment plate part for attaching the insertion part to the housing of the electric motor. The insertion part is formed such that the inner wall thereof has a round shape so as to allow the cable, which extends from the inside of the housing of the electric motor to the outside, to bend in a direction toward the inner side of the electric motor.

Description

Cable guide member and electric motor

[0001] The present invention relates to a cable guide element primarily for electric motors.

[0002] Some electric motors are connected to a variety of leads, such as power supply leads for supplying electric power, drive control leads for supplying multi-phase drive signals that rotate the rotor, and detection signal output leads for reading out detection signals from various sensors (see Patent Documents 1 and 2). These multiple leads can be enclosed and managed together in a single flexible cable to improve usability, for example, when attaching them to the electric motor or when handling them for maintenance.

[0003] JP 2021-164227 A JP 2022-41389 A

[0004] In electric motors applicable to various electric devices such as roller conveyors, belt conveyors, and slider mechanisms, the cable arrangements are diverse, and for example, the cable may be fixed to the device body in a bent state. As a result, stress may be applied locally to the bent portion of the cable, which may generate unnecessary stress in some or all of the multiple lead wires contained in the cable, and this may cause the lead wires to break.

[0005] An exemplary object of the present invention is to improve the reliability of an electric motor by reducing stress applied to a cable, thereby preventing breakage of lead wires that may occur due to the stress.

[0006] One aspect of the present invention relates to a cable guide member, which is attachable to a housing of an electric motor and through which a flexible cable containing one or more lead wires for driving and controlling the electric motor can be inserted, and which comprises: an insertion portion for inserting the cable; and an attachment plate portion for attaching the insertion portion to the housing of the electric motor, and wherein the insertion portion has an inner wall formed in a curved shape so as to allow the cable extending from the inside to the outside of the housing of the electric motor to bend in a direction toward the inside of the electric motor.

[0007] According to the present invention, the reliability of the electric motor can be improved.

[0008] 1 is a perspective view showing a main part of a conveying device as an example of an electrically driven device; FIG. 2 is a perspective view showing a part of the internal structure of an electric motor; FIG. 3 is a perspective view of a cable guide member as viewed from above; FIG. 4 is a perspective view of a cable guide member as viewed from below; FIG. 5 is a perspective view of a cable guide member as viewed from one side; FIG. 6 is a perspective view of a cable guide member as viewed from the other side; FIG. 7 is an enlarged perspective view of a part of the cable guide member; FIG. 8 is a perspective view showing an attachment mode of the cable guide member; FIG. 9 is a perspective view showing an attachment mode of the cable guide member; FIG. 10 is a perspective view showing an attachment mode of the cable guide member; FIG. 11 is a perspective view showing details of an attachment mode of the cable guide member; FIG. 12 is a schematic view for explaining an arrangement mode of cables; FIG. 13 is a perspective view of an end cover; FIG. 14 is a perspective view of an end cover; FIG. 15 is a perspective view showing another example of the structure of the cable guide member;

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Furthermore, the same reference numerals are used for the same or similar components, and redundant explanations will be omitted.

[0010] <First embodiment> Figure 1 is a perspective view showing the main parts of a conveying device 1 which is an application example of an electric motor 2 according to a first embodiment. In this embodiment, the conveying device 1 is a roller conveyor, and in addition to the electric motor 2, it includes a heat sink 3, a cable 4, and a power transmission mechanism 5. In the figure, to facilitate explanation of the structure, an X direction, a Y direction, and a Z direction which are substantially perpendicular to one another are shown, with the X direction corresponding to the width direction, the Y direction corresponding to the depth direction, and the Z direction corresponding to the height direction.

[0011] In this embodiment, a brushless DC motor is used as the electric motor 2, but other known electric motors may also be used. The electric motor 2 is configured with a columnar shape extending primarily in the motor axial direction and, in this embodiment, is assumed to have a substantially cylindrical shape. The electric motor 2 is installed so that the motor axis is parallel to the X direction. Therefore, the curved surface of the housing 20 (see FIG. 2) of the electric motor 2 extends along the X direction, and the end flat surface 20b (see FIG. 2) forming the end flat surface of the housing 20 is substantially parallel to the YZ plane. The electric motor 2 is attached to the frame 10 of the transport device 1 and may be installed while being partially covered by a heat sink 3 for heat dissipation. Note that the frame 10 here is a concept that includes the support base, support plate, and pillars that support the components of the transport device 1 and form the assembly.

[0012] The cable 4 contains one or more lead wires, and in this embodiment contains a plurality of lead wires 41 (see FIG. 6 ), which will be described in detail later. The cable 4 is fixed along the frame 10 and electrically connected to the electric motor 2. The electric motor 2 generates a predetermined power based on a drive signal supplied via the cable 4.

[0013] The power transmission mechanism 5 is installed at the end of the frame 10 in the X direction, receives power from the electric motor 2, and transmits the power to a transport roller (not shown).

[0014] FIG. 2 is a perspective view of the electric motor 2. To visualize part of the internal structure, an end cover 20E (a cap member for sealing the end of the housing 20, which is integrally formed with an end cylindrical portion 20a and an end flat portion 20b) that is part of the housing 20 is not shown. In the electric motor 2 according to this embodiment, a drive control chamber 20Rb is formed by the end cover 20E, adjacent to a power generating chamber 20Ra that houses a stator and a rotor. A circuit board 22 for executing drive control of the electric motor 2 is disposed in the drive control chamber 20Rb, and multiple electronic components may be mounted on the circuit board 22. The end cover 20E is removably fixed to the power generating chamber 20Ra, and in this embodiment, this fixation is achieved by fastening screws Sc. The end cover 20E may be made of any material that can achieve the desired strength, such as resin or metal.

[0015] The multiple lead wires 41 contained in the cable 4 are respectively connected to the multiple connection holes 21 provided on the circuit board 22 (see FIG. 6 ). The circuit board 22 receives power and control signals via the corresponding lead wires 41, rotates the rotor using a multi-phase drive signal, and outputs detection signals read from various sensors to the outside. Examples of the sensors include an encoder and a temperature sensor. The cable 4 is connected to the electric motor 2 by passing through a cable guide member 6 attached to the housing 20 (here, the end cover 20E). Here, each lead wire 41 is connected to a corresponding connection hole 21. Note that in this embodiment, each lead wire 41 is electrically connected by solder while inserted into a corresponding connection hole 21, but the manner of electrical connection is not limited to this example.

[0016] 3A to 3E are perspective views showing the structure of the cable guide member 6. FIG. 3A is a perspective view of the cable guide member 6 as seen from above. FIG. 3B is a perspective view of the cable guide member 6 as seen from below. FIG. 3C is a perspective view of the cable guide member 6 as seen from one side. FIG. 3D is a perspective view of the cable guide member 6 as seen from the other side. FIG. 3E is a diagram showing an enlarged portion of the cable guide member 6. In this embodiment, the cable guide member 6 includes an insertion portion 61 and an attachment plate portion 62. The insertion portion 61 is formed so that the cable 4 can be inserted therethrough, as will be described in detail later.

[0017] The mounting plate portion 62 is a plate-like member integrally molded with the insertion portion 61, and enables the insertion portion 61 to be attached to the housing 20. The mounting plate portion 62 includes extension portions 62a extending to both sides of the insertion portion 61, and fixing portions 62b provided on the extension portions 62a. One or more fixing portions 62b are provided to enable fixing to the housing 20 (here, the end cover 20E), and in this case, the fixing is achieved by fastening a screw.

[0018] As shown in FIG. 3B , the insertion portion 61 is shaped such that its inner wall forms a cylindrical portion 61a and an open portion 61b. The cylindrical portion 61a surrounds the cable 4 connected to the electric motor 2 so as to hold the cable 4 in a substantially straight line. The open portion 61b has a shape that opens outward from the cylindrical portion 61a (in this specification, the direction toward the outside of the electric motor 2 is referred to as the "outward direction." In contrast, the direction toward the inside of the electric motor 2 is referred to as the "inward direction.") More specifically, a bending portion 61c is formed between the cylindrical portion 61a and the open portion 61b to allow the cable 4, which is held by the cylindrical portion 61a and extends outward, to bend in a predetermined direction. Although further details will be described later, this configuration allows the cable 4 leading out from the open portion 61b to be arranged in a shape bent in a predetermined direction.

[0019] 3B, 3C, and 3E, a locking portion 63 is provided on the outer wall of one side of the cylindrical portion 61a. Furthermore, an abutting portion 64a that abuts against the end cover 20E is formed above the locking portion 63 on the outer wall of the one side. Similarly, as shown in FIGS. 3B and 3D, abutting portion 64b that abuts against the end cover 20E is formed on the outer wall of the other side of the cylindrical portion 61a. Furthermore, as shown in FIGS. 3B, 3C, and 3D, abutting portion 64c that abuts against the end cover 20E is formed on the tip side of the cylindrical portion 61a. As will be described in detail later, this configuration determines the position of the mounting plate portion 62, i.e., enables the cable guide member 6 to be positioned.

[0020] 4A1 and 4A2 are perspective views for explaining the state when the cable guide member 6 is attached to the housing 20 (here, the end cover 20E). Figures 4B1 and 4B2 are perspective views showing the state when the cable guide member 6 is attached from a different angle.

[0021] As shown in FIGS. 4A1 and 4B1 , the cable 4 containing multiple lead wires 41 is connected to the electric motor 2 after being inserted through the cable guide member 6, while the end cover 20E can be removed from the housing 20. The cable 4 can be connected to the electric motor 2 by soldering each lead wire 41 to its corresponding connection hole 21 (see FIG. 6 ). The soldering may be performed on the front side (the side opposite the power generating chamber 20Ra) of the circuit board 22, or on the back side (the side facing the power generating chamber 20Ra). In this case, the circuit board 22 may also be removed. Then, as shown in FIGS. 4A2 and 4B2 , the end cover 20E with the cable guide member 6 attached is attached to the housing 20, thereby completing the connection of the cable 4 to the electric motor 2.

[0022] 5 is a perspective view illustrating the details of attaching the cable guide member 6 to the housing 20 (here, the end cover 20E). In this embodiment, the cylindrical end portion 20a forms a curved portion, and the flat end portion 20b forms a flat portion, and they form different surfaces. In the housing 20, an attachment opening 20OP, which is an opening through which the cable guide member 6 is attached, is formed across the cylindrical end portion 20a, which forms the curved portion, and the flat end portion 20b, which forms the flat portion.

[0023] In the drawing, the boundary between the curved surface and the flat surface of the mounting opening 20OP is indicated by a dashed line. The cable guide member 6 is mounted so that the mounting plate 62 corresponds to the flat surface, i.e., so that the mounting plate 62 and the end flat surface 20b form the same plane.

[0024] Here, in the end flat surface portion 20b forming the flat surface portion, a recess 23 is provided around the outer edge of the mounting opening 20OP so that the mounting plate 62 fits in, and the recess 23 forms a mounting surface 23F on which the mounting plate 62 is placed. In addition, mounting surface 23F is provided with mounting portions 24 for attaching the mounting plate 62 as screw holes corresponding to the fixing portions 62b.

[0025] As shown in FIGS. 7A and 7B, the mounting opening 20OP is provided with abutment portions 25a-25c against which the abutment portions 64a-64c (see FIGS. 3B-3E) of the cable guide member 6 abut. The abutment portions 64a-64c of the cable guide member 6 abut against the abutment portions 25a-25c, respectively, thereby preventing the intrusion of foreign matter, such as water, into the housing 20. To further improve waterproofing, the abutment portions 64a-64c and the abutment portions 25a-25c preferably have surface contact. In this state, the locking portion 63 locks or engages with a portion of the end flat portion 20b, thereby enabling the positioning of the cable guide member 6. From this perspective, the abutment portions 25a-25c can be said to function as positioning portions that position the cable guide member 6. One of the contact portions 25a and 64a may be referred to as a contacted portion. Alternatively, one of them may be referred to as a contact surface, or one of them may be referred to as a contacted surface. The same applies to the contact portions 25b and 64b and the contact portions 25c and 64c. For the sake of distinction, for example, if the contact portion 64a is referred to as the first contact portion 64a, the contact portion 64b is referred to as the second contact portion 64b, and the contact portion 64c is referred to as the third contact portion 64c, then the contact portion 25a can be referred to as the first contacted portion 25a, the contact portion 25b can be referred to as the second contacted portion 25b, and the contact portion 25c can be referred to as the third contacted portion 25c.

[0026] With this structure, the cable guide member 6 can be attached to an appropriate position in the housing 20 by fastening the fixing portion 62b and the mounting portion 24 with screws while the mounting plate portion 62 is fitted into the recessed portion 23. At this time, the cable guide member 6 is attached so that the mounting plate portion 62 and the end flat portion 20b form the same plane. The height of the mounting plate portion 62 in the motor axial direction and the height of the recessed portion 23 are approximately the same so that the mounting plate portion 62 and the end flat portion 20b form the same plane. Therefore, with this structure, the electric motor 2 can be installed compactly, and for example, the electric motor 2 can be installed in a relatively narrow area of ​​the conveying device 1, which is advantageous for space saving.

[0027] 6 is a schematic diagram showing the state when the connection of the cable 4 to the electric motor 2 and the attachment of the cable guide member 6 to the housing 20 are completed, as viewed in the motor axial direction. In order to visualize part of the internal structure, the end cover 20E (particularly the end flat portion 20b) is not shown in the figure, and the insertion portion 61 through which the cable 4 is inserted, including the tubular portion 61a, the open portion 61b, and the bent portion 61c, is shown by dashed lines.

[0028] As shown in FIG. 6 , the inner wall of the cylindrical portion 61a on the motor shaft side is connected to an open portion 61b that is open to allow the cable 4 to bend toward the motor shaft, and the inner wall on the opposite side extends outward in a substantially straight line. From another perspective, a portion of the inner wall of the cylindrical portion 61a on the motor shaft side has a relatively wide opening, thereby forming the open portion 61b. Furthermore, the cylindrical portion 61a has a substantially constant outer diameter but a varying inner diameter from the outside to the inside. In this embodiment, the inner diameter at the inside is smaller than the inner diameter at the outside. For ease of explanation, the inner portion of the cylindrical portion 61a with the smaller inner diameter is referred to as a reduced-diameter portion 61a1, and the outer portion with the larger inner diameter is referred to as an expanded-diameter portion 61a2.

[0029] This structure allows the cable 4 to be arranged and led out as follows. That is, first, the cable 4 is held by the reduced-diameter portion 61a1 of the tubular portion 61a on the connection hole 21 side, extending substantially in a straight line. From this perspective, the reduced-diameter portion 61a1 of the tubular portion 61a functions as a holding portion that holds the portion of the cable 4 on the connection hole 21 side so that it is securely connected to the connection hole 21. Furthermore, by holding the cable 4, the reduced-diameter portion 61a1 can prevent foreign matter, such as water, from entering the housing 20. From this perspective, it is preferable that the reduced-diameter portion 61a1 be in surface contact with the cable 4 over substantially the entire area adjacent to it, which further functions as a foreign matter intrusion prevention portion.

[0030] Second, outside the cylindrical portion 61a, the cable 4 can bend inward due to the opening 61b as shown by arrow A1. The opening 61b forms a relatively large opening so that the cable 4 extending outward from the cylindrical portion 61a can be arranged in the bent shape. From this perspective, the opening 61b can be said to function as a guide portion that guides the portion of the cable 4 extending outward from the cylindrical portion 61a so as to allow it to bend inward.

[0031] Third, in order to make it relatively easy to bend the cable 4 by the open portion 61b, the small space formed by the expanded diameter portion 61a2 of the cylindrical portion 61a allows the cable 4 to change its posture by a predetermined amount. From this perspective, it can be said that the expanded diameter portion 61a2 of the cylindrical portion 61a functions as an auxiliary portion that assists the cable 4 in bending.

[0032] The bending portion 61c is located inside the outer edge of the housing 20, which is indicated by the dashed line in the figure. In other words, the cable 4 can bend inside the outer edge of the housing 20. This structure prevents bending of the cable 4 in the X, Y, and Z directions from concentrating at one point or unnecessary twisting of the cable 4, thereby alleviating stress that may be locally applied to the cable 4 due to such bending. The angle formed by the tubular portion 61a and the open portion 61b may be set mainly based on the strength (resistance to bending) of the cable 4. For example, when the diameter of the cable 4 is D and the inner radius of curvature when the cable 4 is bent is r, the angle may be set to satisfy r ≧ K×D (K is a coefficient, for example, K=4).

[0033] According to this embodiment, the cable guide member 6 has an insertion portion 61 for inserting the cable 4, the insertion portion 61 having a curved inner wall that allows the cable 4 extending from the inside to the outside of the housing 20 to bend toward the inside of the electric motor 2. This structure allows for a variety of cable arrangements, such as arranging the cable 4 with or without bending within the housing 20, or ensuring that the degree of bending, if any, is within an acceptable range. This prevents the cable 4 from bending with an unnecessarily large curvature (r<K×D), thereby alleviating stress that may be locally applied to the cable 4. Therefore, according to this embodiment, breakage of the lead wires 41 contained in the cable 4 is suppressed, and the reliability of the electric motor 2 can be improved.

[0034] Furthermore, according to this embodiment, since it is easy to wind the cable 4 around the housing 20, it is possible to extend the cable 4 in a desired direction while winding it around the housing 20. Therefore, this embodiment is advantageous in diversifying the installation modes of the cable 4, and in doing so, there is substantially no increase in the installation space for the electric motor 2. Furthermore, according to this embodiment, before installing the electric motor 2 connected to the cable 4 in the conveyance device 1, the electric motor 2 can be stored with the cable 4 wound around the housing 20, and in this case, there is substantially no increase in the storage space for the electric motor 2.

[0035] In this embodiment, for ease of explanation, the cable 4 is bent at a predetermined angle, but it may be gently curved. In this case, the cylindrical portion 61 a and the open portion 61 b ​​may be shaped so that they are smoothly connected and so that the bent portion 61 c has a curvature. The angle between the cylindrical portion 61 a and the open portion 61 b ​​and / or the curvature of the bent portion 61 c may be set mainly based on the strength of the cable 4, and may be set so that the bend falls within the allowable range for each of the multiple lead wires 41.

[0036] Second Embodiment In the first embodiment described above, the mounting plate 62 forms a flat surface together with the flat end portion 20b, and the cable 4 is led out from the curved surface formed by the cylindrical end portion 20a. However, in other embodiments, these positions may be changed or swapped. That is, the mounting plate 62 may form a curved surface together with the cylindrical end portion 20a, and / or the cable 4 may be led out from the flat surface formed by the flat end portion 20b. When the mounting plate 62 forms a curved surface, it is sufficient that the mounting plate 62 is formed in a curved shape with substantially the same curvature as the cylindrical end portion 20a. In this case, the insertion portion 61 may be formed at least partially in a flat shape to form the flat end portion 20b.

[0037] FIG. 8 is a perspective view showing the structure of a cable guide member 6' according to the second embodiment. The cable guide member 6' includes an insertion portion 61' and an attachment plate portion 62'. In this embodiment, the attachment plate portion 62' is curved and, together with the cylindrical end portion 20a, forms a curved surface. Meanwhile, the insertion portion 61' is partially flat and, together with the flat end portion 20b, forms a flat surface. The cylindrical portion 61a, the open portion 61b, the bent portion 61c, and the abutment portions 64a to 64c may be provided on the flat insertion portion 61', as in the first embodiment. This allows the cable guide member 6' to be securely fixed to the housing 20 (here, the end cover 20E). This embodiment also achieves the same effects as the first embodiment.

[0038] In yet another embodiment, the mounting plate 62 may form both a flat portion and a curved portion together with the cylindrical end portion 20 a and the flat end portion 20 b. In this case, the mounting plate 62 may be formed in a bent shape in which the portion forming the flat portion and the portion forming the curved portion are connected. In this configuration, the cable 4 may be led out from either the curved portion side or the flat portion side.

[0039] <Others> In the above embodiment, the conveying device 1 is shown as a typical application example of the electric motor 2 (see FIG. 1), but the electric motor 2 can be applied to a variety of electric devices capable of transmitting power, within the scope of the spirit of the invention.

[0040] In the above description, for ease of understanding, each element is denoted by a name related to its function. However, each element is not limited to having the content described in the embodiment as its main function, but may have an auxiliary function. Furthermore, the individual terms used in this specification are used only for the purpose of explaining the present invention, and the present invention is not limited to the strict meaning of the terms. For example, the term "apparatus" may be replaced with "unit," "assembly," "device," "module," etc., and vice versa.

[0041] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

[0042] 2: electric motor, 20: housing, 4: cable, 6: cable guide member, 61: insertion portion, 62: mounting plate portion.

Claims

1. It is an electric motor, A housing that includes at least a stator and rotor, The device comprises a cable guide member that can be attached to the housing and through which a flexible cable containing one or more lead wires for controlling the drive of the electric motor can be inserted, The cable guide member is An insertion section for inserting the aforementioned cable, A mounting plate portion for attaching the insertion portion to the housing, It is equipped with such a feature, and the mounting plate portion and the housing are mounted so that they form the same surface. The insertion portion is formed with a curved inner wall so as to allow the cable extending from the inside to the outside of the housing to bend toward the inside of the electric motor. The housing includes a first surface, a second surface that forms a surface different from the first surface, and a mounting opening to which the cable guide member is attached, the mounting opening being formed spanning the first surface and the second surface. The cable guide member is mounted such that the mounting plate portion corresponds to at least one of the first surface portion and the second surface portion. In at least one of the first and second surfaces, a recess is provided around the outer edge of the mounting opening into which the mounting plate can be fitted. An electric motor characterized by the following features.

2. The inner wall of the insertion portion is A cylindrical portion surrounds the first portion of the cable that extends in a straight line and is connected to the electric motor, An open portion having a shape that is open to the outside of the cylindrical portion, Includes, The opening includes an outlet that guides out the second portion of the cable, which extends outward from the cylindrical portion, so as to allow the second portion to bend toward the inside of the electric motor. The electric motor according to claim 1, characterized in that it is as described above.

3. The outer wall of the cylindrical portion is provided with a locking portion that engages with at least a part of the housing. The electric motor according to claim 2, characterized in that it is as described above.

4. The aforementioned mounting plate portion is An extended portion that extends to both sides of the insertion portion, One or more fixing parts are provided on the extended portion for securing the electric motor to the housing, including The electric motor according to claim 1, characterized in that it is as described above.

5. The electric motor has a cylindrical shape, and when viewed in the direction of the motor shaft, the bent portion of the inner wall of the insertion part is located inside the outer edge of the housing. The electric motor according to claim 1, characterized in that it is as described above.

6. A mounting surface is formed on one of the first and second surfaces on which the mounting plate is placed, and a mounting portion for attaching the mounting plate is provided on the mounting surface. The electric motor according to claim 1, characterized in that it is as described above.

7. The mounting opening is formed with a positioning portion that engages with the mounting plate to position the cable guide member. The electric motor according to claim 1, characterized in that it is as described above.

8. The cable guide member includes a first contact portion, a second contact portion, and a third contact portion. The positioning portion includes a first contact portion, a second contact portion, and a third contact portion. The first contact portion, the second contact portion, and the third contact portion are in surface contact with the first contacted portion, the second contacted portion, and the third contacted portion, respectively. The electric motor according to claim 7, characterized in that it is as described above.