Cable mounting structure for electric apparatus

[0001] This invention relates to a cable mounting structure for an electric apparatus.

[0002] An electric apparatus is required to have waterproof properties and dustproof properties in order to prevent a failure or a malfunction in the electric apparatus itself which may occur depending on an environment where it is used. As a method for fulfilling such a requirement, there is adopted, for example, a technique in which an electric apparatus body is accommodated within a closed or sealed housing. Even with such a technique, the electric apparatus body accommodated in the housing needs to be connected to the outside of the housing with the use of a cable, with the aim of supplying electric power from outside to the electric apparatus body, or transmitting and receiving control signals and data signals for the electric apparatus body. For this purpose, a cable mounting structure for the electric apparatus is also required to have waterproof properties and dustproof properties. Technologies for fitting a grommet over the cable, and mounting the grommet on the housing in an intimately contacted state have been developed (see, for example, Patent Documents 1 and 2).

[0003] In connection with the electromechanical device described in Patent Document 1, the application of a cable mounting structure to a motor (electric rotating machine) will be concretely described with reference to FIG. 5.

[0004] As shown in FIG. 5, an electric rotating machine (stator and rotor) 101, which is an electric apparatus body of a motor, is accommodated within a housing 102. If the electric rotating machine 101 is accommodated within the housing 102 in this manner, there are restrictions in the diametrical direction within the housing 102. Thus, a cable mounting structure 120 for the electric apparatus designed to mount a cable 111 is provided at one end 102a of the housing 102. A grommet 114 is mounted on the cable 111, and connectors 112, 113 are attached to both ends of the cable 111. The cable mounting structure 120 for the electric apparatus is furnished with a fixing section 121 provided to protrude from the one end 102a of the housing 102, and a lid 122 for closing the fixing section 121. The fixing section 121 has a protruding portion 121a continuous with a peripheral wall section 102b of the housing 102 and extending in the same direction as the axis C10 of the housing 102, and a side wall portion 121b continuous with the protruding portion 121a and extending toward the axis C10 of the housing 102. One of the connectors, 112, is disposed within the housing 102, while the other connector 113 is disposed outside the housing 102. The grommet 114 is placed on the side wall portion 121b of the fixing section 121, and rendered stationary by the lid 122, whereby the waterproof properties and dustproof properties of the cable mounting structure 120 for the electric apparatus are ensured.

[0005] The mounting structure for an electric component described in Patent Document 2 will be concretely described with reference to FIG. 6.

[0006] As shown in FIG. 6, an electric apparatus body (not shown) is accommodated within a housing 201. A through-hole 202 is provided in the housing 201, and a cable 211 is mounted at this site. Connectors 212, 213 are attached to both ends of the cable 211, and a rubber bushing 215 is provided to have the cable 211 inserted therethrough. Through this through-hole 202, one of the connectors, 212, is disposed within the housing 201, and the other connector 213 is disposed outside the housing 201. The rubber bushing 215 is mounted in the through-hole 202, whereby the waterproof properties and dustproof properties of the cable mounting structure for the electric apparatus are ensured.

• [0007] Patent Document 1: JP-A-2002-369346
• [0008] Patent Document 2: JP-A-06-58537

[0009] With the electromechanical device having the mounting structure applied to the motor mentioned above, however, the lid 122 has to be disposed parallel to the cable 111, and the fixing section 121 for fixing the lid 122 is provided outside the housing 102. Thus, it has been difficult to achieve downsizing.

[0010] With the aforementioned mounting structure for the electrical component, the size of the connector 212 which can be disposed within the housing 201 is restricted by the size of the through-hole 202. That is, if the connector 212 is of a large shape, the through-hole 202 becomes large according to the size of the connector 212, and the rubber bushing 215 for closing the through-hole 202 also becomes large in size. As a result, downsizing has been difficult to achieve.

[0011] The present invention has been proposed in the light of the above-mentioned problems. It is an object of the invention to provide a cable mounting structure for an electric apparatus, which ensures sealing properties, such as waterproof properties and dustproof properties, and which can effectively contribute to downsizing, while easing restrictions on the size of a connecting tool mounted on one end of a cable connected to an electric apparatus body.

[0012] A cable mounting structure for an electric apparatus according to a first aspect of the invention, intended for solving the above problems, is a cable mounting structure for an electric apparatus, comprising a housing for accommodating an electric apparatus body, a cable connected to the electric apparatus body via a connecting tool, a grommet mounted on the cable, a recessed section provided in the housing, and a lid for closing the recessed section,

[0013] wherein the recessed section is formed in a closed-bottomed tubular shape recessed inwardly of the housing, a fixing section for fixing the grommet thereto is provided in a peripheral wall section of the recessed section, and a pass-through section through which the cable is passed is provided in the lid, and

[0014] the connecting tool is disposed within the recessed section, and the pass-through section is positioned to the grommet.

[0015] A cable mounting structure for an electric apparatus according to a second aspect of the invention, intended for solving the above problems, is the cable mounting structure for an electric apparatus according to the first aspect of the invention, wherein

[0016] the pass-through section has a communicating portion communicating with an edge of the lid, and

[0017] the fixing section has a communicating section communicating with the peripheral wall section of the recessed section.

[0018] A cable mounting structure for an electric apparatus according to a third aspect of the invention, intended for solving the above problems, is the cable mounting structure for an electric apparatus according to the second aspect of the invention, wherein

[0019] the communicating portion in the pass-through section and the communicating section in the fixing section are formed to be offset with respect to each other.

[0020] With the cable mounting structure for an electric apparatus according to the present invention, the recessed section is formed in a closed-bottomed tubular shape recessed inwardly of the housing, the fixing section for fixing the grommet mounted on the cable is provided in the peripheral wall section of the recessed section, and the pass-through section through which the cable is passed is provided in the lid, and the connecting tool is disposed within the recessed section, and the pass-through section is positioned to the grommet. Thus, the sealing properties such as waterproof properties and dustproof properties can be ensured. Regardless of the size of the pass-through section, the connecting tool can be disposed within the recessed section, and restrictions on the size of the connecting tool can be eased. Furthermore, the grommet and the connecting tool can be disposed within the recessed section of the housing. Thus, this configuration can effectively contribute to downsizing.

[0021] With the cable mounting structure for an electric apparatus according to the present invention, the pass-through section has the communicating portion communicating with the edge of the lid, and the fixing section has the communicating section communicating with the peripheral wall section of the recessed section. Thus, the sealed state of the recessed section by the lid can be ensured more reliably. Moreover, the grommet can be easily fixed to the fixing section, and the pass-through section can be easily positioned to the grommet. Furthermore, the structure is so simple that an increase in the production cost can be curtailed.

[0022] With the cable mounting structure for an electric apparatus according to the present invention, the communicating portion in the pass-through section and the opening section in the fixing section are formed to be offset with respect to each other. Thus, the sealed state of the recessed section by the lid can be ensured even more reliably.

[0029] A mode for putting into practice a cable mounting structure for an electric apparatus according to the present invention will be described concretely based on an embodiment of the invention.

[0030] A cable mounting structure for an electric apparatus according to a first embodiment of the present invention will be described by reference to FIGS. 1 to 4.

[0031] The cable mounting structure for an electric apparatus according to the first embodiment of the present invention, as shown in FIG. 1, is a cable mounting structure for an electric apparatus, adapted to mount a cable 11, which connects an electric apparatus body 1 to the outside of a nearly cylindrical housing 10 for accommodating the electric apparatus body 1, to the housing 10. The cable mounting structure is provided on one end 10a of the housing 10. As the electric apparatus body 1, there is named the one required to have waterproof properties and dustproof properties depending on an environment for its use, for example, an electric rotating machine having a stator and a rotor.

[0032] The cable 11 has a first cable 11a and a second cable 11b. The first cable 11a has one end (end facing the electric apparatus body 1) to which a first connector 12 (connecting tool) is attached, and has the other end to which a second connector 18 (connecting tool) is attached. The second cable 11b has one end (end facing the electric apparatus body 1) to which a third connector (connecting tool; not shown) is attached, and has the other end to which the second connector 18 is attached. The first cable 11a and the second cable 11b pass through grommets 20, and the first cable 11a and the second cable 11b are mounted through the grommets 20. Examples of the first cable 11a and the second cable 11b are a power supply cable for supplying electricity to the electric apparatus body 1, and a signal cable for transmission and reception of a control signal and a data signal between the electric apparatus body 1 and the outside.

[0033] At the one end 10a of the housing 10, there is provided a recessed housing section 15 (recessed section) for accommodating the first connector 12 attached to the first cable 11a, and the third connector attached to the second cable 11b. The recessed housing section 15 is formed in a closed-bottomed tubular shape recessed inwardly of the housing. As shown in FIGS. 2(a), 2(b), a grommet mounting hole (fixing section) for fixing the grommet 20 thereto is provided in a peripheral wall section 15a of the recessed housing section 15. The grommet mounting hole 16 is shaped to extend in the same direction as the axial direction C1 of the housing 10 and to extend along the peripheral wall section 15a. As shown in FIG. 1, therefore, the grommet 20 of a rectangular parallelepipedal shape can be disposed to face the axial direction C1 of the housing 10. Moreover, the first cable 11a and the second cable 11b can be arranged in a bent state, and the first connector 12 of a rectangular parallelopipedal shape and the third connector of a rectangular parallelopipedal shape can be arranged to head in the diametrical direction of the housing 10. Thus, the first connector 12 and the third connector which are larger than the grommet 20 can be disposed within the recessed housing section 15.

[0034] The grommet mounting hole 16 is provided with a communicating section 17 for bringing the grommet mounting hole 16 into communication with the recessed housing section 15, as shown in FIGS. 1 and 2. That is, the grommet mounting hole 16 is in a shape communicating with the peripheral wall section 15a of the recessed housing section 15. Thus, the first cable 11a and the second cable 11b can be inserted from the communicating section 17 into the grommet mounting hole 16. The second connector 18 attached to the first cable 11a and the second cable 11b is disposed outside the recessed housing section 15 (outside the housing 10). Hence, the first cable 11a is connected to the electric apparatus body 1 via the first connector 12, and is connected via the second connector 18 to a control device or the power supply which is placed outside the housing 10. For example, a third cable 13 is connected to the first connector 12, as shown in FIG. 3. The third cable 13 is passed through a hole 10b provided in the end 10a of the housing 10, and is connected to a sensor 14 which can be included in a part of the configuration of the electric apparatus body 1 placed within the housing 10. An example of the sensor 14 is a measuring instrument which can measure various data on the electric apparatus body 1, etc. within the housing 10. The second cable 11b is connected to the electric apparatus body 1 via the third connector, and is connected via the second connector 18 to the control device or the power supply which is placed outside the housing 10.

[0035] The above-mentioned grommet 20, as shown in FIG. 2(a), is formed in a nearly cylindrical shape (tubular shape) extending along the cable 11, and has a pass-through portion 21 through which the cable 11 is inserted, and a flange portion 23 provided outwardly of the pass-through portion 21 and extending in the diametrical direction. The flange portion 23 is formed at a site nearly intermediate between a leading end 20a and a rear end 20b of the grommet 20. Further, the grommet 20 has a rib portion 24 formed to be nearer to the rear end 20b than to the flange portion 23 and protrude outwardly. The rib portion 24 is formed to be smaller than the flange portion 23 in a diametrical cross section.

[0036] The grommet mounting hole 16 is provided with a rib close contact portion 16a which the rib portion 24 of the grommet 20 intimately contacts, and a stepped portion 16b which the flange portion 23 of the grommet 20 is brought into engagement with. A cable pass-through portion 16c is provided in communication with the rib close contact portion 16a of the grommet mounting hole 16, and the cable 11 can be inserted into the cable pass-through portion 16c. The rib close contact portion 16a and the stepped portion 16b are also in communication. Thus, when the grommet 20 is inserted into the grommet mounting hole 16, the rib portion 24 of the grommet 20 contacts the rib close contact portion 16a of the grommet mounting hole 16 to produce a pushing pressure. Thus, the flange portion 23 of the grommet 20 is brought into engagement with the stepped portion 16b, whereby the grommet 20 is fixed in the grommet mounting hole 16, as shown in FIG. 2(b). As a result, the cable 11 fixed to the grommet 20 is also fixed to the housing 10.

[0037] On the side of the one end 10a of the housing 10, a stepped section 10b is formed on the outer periphery of the recessed housing section 15, as shown in FIG. 1. An edge 30a of a lid 30 is positioned at the stepped section 10b to close the recessed housing section 15. The lid 30 is fixed to the one end 10a of the housing 10 by fixtures 33 such as bolts. The lid 30 is provided with pass-through sections 31 which are located in the grommet mounting holes 16 provided in the housing 10 when the lid 30 is positioned at the fixing position of the housing 10, and through which the first cable 11a and the second cable 11b are passed. Concretely, the pass-through section 31 is provided to be inscribed in the edge 30a of the lid 30, and the pass-through section 31 is provided with a communicating portion 32 which allows the pass-through section 31 to communicate with the edge 30a of the lid 30, as shown in FIG. 1. The communicating portion 32 is formed to be smaller in a diametrical cross section than the flange portion 23 of the grommet 20. Thus, the first cable 11a, the second cable 11b, and the leading end 20a of the grommet 20 can be inserted through the communicating portion 32 into the pass-through section 31. With the grommet 20 being mounted in the grommet mounting hole 16 of the housing 10, the pass-through section 31 of the lid 30 is positioned at the flange portion 23 of the grommet 20, and fixed to the one end 10a of the housing 10 by the fixture 33. By so fixing the grommet 30 to the housing 10 by the lid 30, a pushing pressure occurs at the flange portion 23.

[0038] In the diametrical cross section, therefore, the communicating section 17 of the grommet mounting hole 16 and the communicating portion 32 of the lid 30 are arranged in offset relationship, so that the sealing properties, such as waterproof properties and dustproof properties, of the interior of the recessed housing section 15 are improved. That is, the offset refers to a state in which the communicating section 17 of the grommet mounting hole 16 and the communicating portion 32 in the pass-through section 31 of the lid 30 are displaced with respect to each other in the diametrical direction.

[0039] The flange portion 23 and rib portion 24 of the grommet 20 may be coated with a liquid sealing material (e.g., silicone sealing material), whereby the waterproof properties can be further enhanced.

[0040] The cable mounting structure for an electric apparatus according to the present embodiment, as noted above, comprises the housing 10, the first cable 11a and the second cable 11b connected to the electric apparatus body 1 via the first connector 12 and the third connector, and the lid 30 for closing the recessed housing section 15 provided in the housing 10. The recessed housing section 15 is formed in a closed-bottomed tubular shape recessed inwardly of the housing. The grommet mounting holes 16 for fixing the grommets 20 mounted on the first cable 11a and the second cable 11b are provided in the peripheral wall section 15a of the recessed housing section 15. The pass-through sections 31 through which the first cable 11a and the second cable 11b pass are formed in the lid 30. The grommet 20 is fixed in the grommet mounting hole 16, while the first connector 12 and the third connector are placed within the recessed housing section 15, and the pass-through section 31 is positioned to the grommet 20. Simply by closing the recessed housing section 15 with the lid 30, therefore, the sealing properties such as waterproof properties and dustproof properties can be ensured. Regardless of the size of the pass-through section 31, the first connector 12 and the third connector can be disposed within the recessed housing section 15, and restrictions on the sizes of the first connector 12 and the third connection can be eased. Furthermore, the grommet 20, the first connector 12 and the third connector can be disposed within the recessed housing section 15 of the housing 11. In addition, the grommet 20, the first connector 12 and the third connector can be arranged within the recessed housing section 15 of the housing 10, without being disposed on the same straight line. Thus, the configuration in the present embodiment can effectively contribute to downsizing.

[0041] The above descriptions have been offered using the cable mounting structure for an electric apparatus which accommodates the electric rotating machine, as the electric apparatus body 1, within the housing 10. However, the present invention can be applied to the cable mounting structure for an electric apparatus which accommodates a converter or the like, instead of a motor, within a housing.

[0042] Explanations have been offered using the cable mounting structure for an electric apparatus in which the cable 11 having one end divided in two, i.e., the first cable 11a and the second cable 11b, is mounted on the one end 10a of the housing 10. However, the cable mounting structure for an electric apparatus may be one which has one cable or many cables mounted on the one end of the housing.

[0043] The present embodiment has been described using the cable mounting structure for an electric apparatus in which the first connector 12 is connected to the sensor 14 disposed within the housing 10 via the third cable 13. However, the present invention can be applied to the cable mounting structure for an electric apparatus which is connected to a connector disposed within the housing 10 and connectable to the electric apparatus body 1, instead of being connected to the sensor 14. By so doing, the first cable 11a can be connected to the electric apparatus body 1 within the housing 10.

[0044] The cable mounting structure for an electric apparatus ensures sealing properties, such as waterproof properties and dustproof properties, and can effectively contribute to downsizing, while easing restrictions on the size of the connecting tool mounted on one end of the cable connected to the electric apparatus body. Hence, the cable mounting structure can be utilized very advantageously in the electric machinery and apparatus industry and so on.

• • [0045] 1 Electric apparatus body
  • [0046] 10 Housing
  • [0047] 11 Cable
  • [0048] 11a First cable
  • [0049] 11b Second cable
  • [0050] 12 First connector
  • [0051] 15 Recessed housing section
  • [0052] 15a Peripheral wall section
  • [0053] 16 Grommet mounting hole
  • [0054] 17 Communicating section
  • [0055] 18 Second connector
  • [0056] 20 Grommet
  • [0057] 23 Flange portion
  • [0058] 24 Rib portion
  • [0059] 30 Lid
  • [0060] 31 Pass-through section
  • [0061] 32 Communicating portion