Patent Publication Number: US-9431752-B2

Title: Connector device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/JP2014/060000, filed Apr. 4, 2014, and based upon and claims the benefit of priority from Japanese Patent Application No. 2013-080428, filed Apr. 8, 2013, the entire contents of all of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present application relates to a connector device which fits between a pair of housing parts, thereby electrically connecting respective terminals provided in the pair of housing parts, with each other. 
     BACKGROUND ART 
     Conventionally, there have been proposed a variety of connector devices each installed in an engine (see US 2010/0003841 A1). A conventional example of such a connector device is illustrated in  FIG. 18 . As illustrated in  FIG. 18 , a conventional connector device  50  is installed in a cylinder head  70  of an engine to pick up an output of a built-in fuel pressure sensor element (not illustrated). The conventional connector device  50  includes a wire harness side connector  51  and a sensor side connector  60 . 
     The wire harness side connector  51  includes a housing part  52 . A first terminal  53  is disposed in an interior portion on one end side of the housing part  52 . An external terminal  54  is disposed in an interior portion on the other end side of the housing part  52 . The first terminal  53  is connected to the external terminal  54  through wires W accommodated in the housing part  52 . The housing part  52  includes a connector fitting part  52   a  housing the external terminal  54 . An external connector (not illustrated) is fitted to the connector fitting part  52   a.    
     The sensor side connector  60  includes a sensor body part  61  in which a sensor element (not illustrated) is disposed, and a housing part  63  which is fixed to the sensor body part  61  and in which a second terminal  62  is disposed. A threaded part  61   a  is formed on the outer circumference of the sensor body part  61 . By screwing the sensor body part  61  into a threaded hole  70   a  of the cylinder head  70 , the sensor side connector  60  is installed in the cylinder head  70 . 
     With the above mentioned constitution, the sensor side connector  60  is installed in the cylinder head  70  and thereafter, a head cover  71  is mounted on the cylinder head  70 . Then, the wire harness side connector  51  is inserted into a hole  71   a  of the head cover  71  and fitted to the sensor side connector  60 . 
     The sensor side connector  60  is screw fastened to the threaded hole  70   a  of the cylinder head  70 . Accordingly, the rotational position (orientation) of the housing part  63  of the sensor side connector  60  is non-constant and furthermore, when fitting the wire harness side connector  51 , the housing part  63  of the sensor side connector  60  is located deep in the hole  71   a  of the head cover  71 . Therefore, the housing part  63  of the sensor side connector  60  cannot be visually recognized clearly, so that it is difficult to align the housing part  52  of the wire harness side connector  51  with a formal fitting rotational position with respect to the housing part  63  of the sensor side connector  60 , causing a problem of inferior fitting workability. 
     In such a situation, this applicant has proposed a connector device having good fitting workability. This connector device includes a first connector including a first housing part in which a first terminal is disposed, and a second connector including a second housing part in which a second terminal is disposed. In operation, the first housing part and the second housing part are fitted to each other, and the first terminal and the second terminal are connected together at a fitting completion position. Then, the first connector includes a third connector rotatably attached to the first housing part, while the third connector includes a third housing part in which a third terminal is disposed. In the connector device, the first terminal and the third terminal are connected to each other through a wire. The first housing parts is provided with a guide rib part, while the third housing parts is provided with a rotational direction guiding part which guides the guide rib part in a manner that the first housing part and the second housing part are brought into their formal fitting rotational positions by the time when the first terminal and the second terminal start to come into contact with each other. 
     With the above mentioned constitution, even if the rotational position of the second housing part cannot be specified, the fitting operation between the first housing part and the second housing part could be accomplished with ease. Additionally, as the first terminal and the third terminal are connected to each other through the wire, it is possible to realize the improvement of reliability with respect to electrical connection, reduction in number of components, etc. in comparison with electrical connection using contacts, such as rotational contacts. 
     SUMMARY 
     By the way, in the above mentioned connector device, when the fitting of the first connector on the wire harness side to the second connector on the sensor side is released, the wire in the first connector becomes remained to be twisted. Additionally, with re-fitting of the connectors, an excessive twist may occur in the wire. The twisting of the wire is not preferable due to stress on the wire, etc. 
     In order to solve the above mentioned problem, therefore, an object of the present application is to provide a connector device which allows for the connector fitting action and which can prevent a wire from being twisted in a connector separated state as much as possible. 
     A connector device according to an aspect of the present application includes: a first connector including a first housing part in which a first terminal is disposed; and a second connector including a second housing part in which a second terminal is disposed. The first connector includes a third housing part provided so as to be rotatable to the first housing part. The third housing part is provided with an external connector fitting part in which a third terminal is disposed. The third terminal and the first terminal are connected to each other through a wire. When the fitting orientation of the first housing part is different from the fitting orientation of the second housing part, the first housing part rotates in relation to the third housing part, thereby fitting the second housing. The first terminal is connected to the second terminal under condition that fitting of the connectors is complete. The first housing part is axially movable to the third housing part between a pre-fitting position thereof and a fitting completion position thereof, the first housing part being urged toward the pre-fitting position by an urging member. The connector device is provided with a rotational position return mechanism that returns, when the fitting of the connectors is released, the rotational position of the first housing part to an initial rotation position thereof during a process in which the first housing part is moved from the fitting completion position to the pre-fitting position by an urging force of the urging member. 
     Preferably, the connector device further includes a rotation preventing mechanism that prevents the first housing part under the pre-fitting position from rotating to the third housing part. 
     The rotational position return mechanism may include: a guide rail provided in one of the first housing part and the third housing part; and a guide pin guided by the guide rail during an axial movement of the first housing part from the fitting completion position up to the pre-fitting position. 
     An inner cylindrical body may be rotatably attached to the first housing part. The third housing part may be rotatably attached to the first housing part through the inner cylindrical part. The rotational position return mechanism may include: a first guide rail provided in one of the third housing part and the inner cylindrical body; a second guide pin provided in the other of the third housing part and the inner cylindrical body and also guided by the first guide rail during an axial movement of the first housing part from the fitting completion position up to the pre-fitting position; a second guide rail provided in one of the inner cylindrical body and the first housing part; and a third guide pin provided in the other of the inner cylindrical body and the first housing part and also guided by the second guide rail during the axial movement of the first housing part from the fitting completion position up to the pre-fitting position. 
     The inner cylindrical body may be provided, in each of vertically symmetric positions thereof, with one of the first guide rail and the second guide pin and one of the second guide rail and the third guide pin. 
     One of the first housing part and the second housing part may be provided with a guide rib, while the other of the first housing part and the second housing part may be provided with a rotational direction guiding part that guides the guide rib so that even if the guide rib is positioned in any rotational position, the first housing part and the second housing part would be brought into formal fitting rotational positions by a position previous to the time when the first terminal and the second terminal start to come into contact with each other, whereby the first housing part rotates to fit the second housing when the fitting orientation of the first housing part is different from the fitting orientation of the second housing part. 
     With the aspect of the present application, at the time of connector fitting, when the first housing part is subjected to pressing force from the second housing, the first housing part moves from the pre-fitting position toward the fitting completion position against urging force of the urging member. If the fitting orientation of the first housing part is different from the fitting orientation of the second housing part, then the first housing part rotates to the third housing part to face the formal fitting rotational position and fits the second housing part. At the time of releasing the connector fitting, meanwhile, when the pressing force from the second housing part to the first housing part is released, the first housing part moves from the fitting completion position to the pre-fitting position by the urging force of the urging member. In the process of this movement, the rotating direction of the first housing part is returned to the initial rotational position by the initial position return mechanism. Therefore, it is possible to accomplish the connector fitting action and also possible to prevent the wire from being twisted in the connector separated state, as much as possible. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of the connector device according to a first embodiment in a pre-fitting condition. 
         FIG. 2  is a perspective view of the connector device according to the first embodiment in a fitting completion condition. 
         FIG. 3  is an exploded front view of the connector device according to the first embodiment. 
         FIG. 4  is an exploded perspective view of an essential part of the connector device according to the first embodiment. 
         FIG. 5  is a perspective view of a first housing accommodated in an outer cylindrical body of a third housing of the connector device according to the first embodiment. 
         FIG. 6A  is a perspective view of a part D 1  of  FIG. 5 , viewed from its inner face and,  FIG. 6B  is a perspective view of a part D 2  of  FIG. 5 . 
         FIG. 7A  is a view illustrating the movement trace of a first lock part in the connector fitting process of the connector device according to the first embodiment,  FIG. 7B  is a view illustrating the movement trace of a second lock part in the connector fitting process of the connector device according to the first embodiment  FIG. 7C  is a sectional view taken along a line Al-Al of  FIG. 7A , and  FIG. 7D  is a sectional view taken along a line B 1 -B 1  of  FIG. 7B . 
         FIG. 8A  is a view illustrating the movement trace of the first lock part in the connector fitting releasing process of the connector device according to the first embodiment,  FIG. 8B  is a view illustrating the movement trace of the second lock part in the connector fitting releasing process of the connector device according to the first embodiment,  FIG. 8C  is a sectional view taken along a line A 2 -A 2  of  FIG. 8A , and  FIG. 8D  is a sectional view taken along a line B 2 -B 2  of  FIG. 8B . 
         FIG. 9  is a perspective view of a connector device according to a second embodiment. 
         FIG. 10A  is perspective view of the connector device according to the second embodiment in a pre-fitting condition, and  FIG. 10B  is a perspective view of the connector device according to the second embodiment in a fitting completion condition. 
         FIG. 11  is an exploded front view of the connector device according to the second embodiment. 
         FIG. 12A  is a perspective view of an outer cylindrical body of the connector device according to the second embodiment, and  FIG. 12B  is a sectional view taken along a line C-C of  FIG. 12A . 
         FIG. 13A  is a perspective view of an inner cylindrical body of the connector device according to the second embodiment, and  FIG. 13B  is a sectional view taken along a line D-D of  FIG. 13A . 
         FIG. 14A  is a view illustrating the positions of first to third guide pins of the connector device according to the second embodiment, in a pre-fitting position, and  FIG. 14B  is a view illustrating the positions of the first to third guide pins of the connector device according to the second embodiment, in a fitting completion position. 
         FIG. 15A  is a sectional view taken along a line E-E of  FIG. 14B , and  FIG. 15B  is a perspective view of an essential part, illustrating the position of the second guide pin of the connector device according to the second embodiment, in the fitting completion position. 
         FIG. 16A  is a sectional view taken along a line F-F of  FIG. 14B , and  FIG. 16B  is a perspective view of an essential part, illustrating the position of the third guide pin of the connector device according to the second embodiment, in the fitting completion position. 
         FIG. 17  is a perspective view of an inner cylindrical body according to a modification of the inner cylindrical body of the connector device according to the second embodiment. 
         FIG. 18  is a perspective view of a conventional connector device in a pre-fitting condition. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present application will be described with reference to  FIGS. 3 to 14 . 
     First Embodiment 
       FIGS. 1 to 8  illustrate a first embodiment. As illustrated in  FIGS. 1 to 4 , a connector device A according to the first embodiment includes a built-in combustion pressure sensor (not illustrated) and is mounted on e.g. an engine head. The connector device A includes a wire harness side connector  1  as a first connector, and a sensor side connector  30  as a second connector. 
     The wire harness side connector  1  includes a first housing part  2  including a built-in first terminal (not illustrated), and a third housing part  10  rotatably supported by the first housing part  2 . An inner cylindrical body  5  is fixed on the top of the first housing part  2  coaxially, by fitting between fitting pins pin  2   a  and fitting grooves  13   a.    
     The third housing part  10  includes an external connector fitting part  11  having a built-in third terminal (not illustrated), an attachment flange part  12 , and an outer cylindrical body  13 . The external connector fitting part  11 , the attachment flange part  12 , and the outer cylindrical body  13  constitute an integral member. The third terminal and the first terminal are connected to each other through electrical wires W routed in the outer cylindrical body  13 . Each of the wires W is routed with a surplus length allowing it to be twisted. The external connector fitting part  11  defines a direction generally perpendicular to the fitting direction of the first housing part  2 . Fitted into the external connector fitting part  11  is an external connector (not illustrated) which is connected to a wire harness (not illustrated) on a side of a vehicle body. In the outer cylindrical body  13 , its upper part is formed with a small diameter, while the lower part is formed with a large diameter. 
     Inside the outer cylindrical body  13 , as illustrated in  FIG. 5 , the first housing part  2  and the inner cylindrical body  5  are accommodated so as to be movable in the axial direction and also rotatable about their own axes. The first housing part  2  and the inner cylinder body  5  rotate integrally. The lower part of the first housing part  2  is exposed from the lower end of the outer cylindrical body  13 . The first housing part  2  and the inner cylindrical body  5  are urged against a pre-fitting position by elastic force of a spring  14  as an urging member housed in the outer cylindrical body  13 . However, their axial moving ranges and rotatable positions in relation to the outer cylindrical body  13  are restricted by the following structure. The structure will be described below. 
     As illustrated in  FIGS. 5 and 6 , the outer cylindrical body  13  is provided with a first guide pin  15  and a second guide pin  16  which protrude from an inner surface of the outer cylindrical body  13 . The first guide pin  15  and the second guide pin  16  are arranged in respective rotational positions located an angle of substantially 180 degrees apart. With pressing forces applied from the inside, the first guide pin  15  and the second guide pin  16  can withdraw from the inner surface outwardly due to elastic displacements of respective slits s. 
     As illustrated in  FIGS. 7A to 7D and 8A to 8D , the inner cylindrical body  5  is provided, in order from its upper position toward the lower position, with a guide rail  20  arranged over the entire circumference in the circumferential direction, a first vertical restriction wall  21  arranged along the axial direction, a first horizontal restriction wall  22  arranged in the circumferential direction, a second vertical restriction wall  23  arranged along the axial direction, a second horizontal restriction wall  24  arranged in the circumferential direction, a third vertical restriction wall  25  arranged along the axial direction, a third horizontal restriction wall  26  arranged over the entire circumference in the circumferential direction, a fourth vertical restriction wall  27  arranged along the axial direction, and a fourth horizontal restriction wall  28  arranged over the entire circumference in the circumferential direction. 
     In the pre-fitting position of the inner cylindrical body  5 , the inner cylindrical body  5  is subjected to the elastic force of the spring  14  under condition that the first guide pin  15  abuts on the uppermost face of the guide rail  20 , while the second guide pin  16  abuts on the second horizontal restriction wall  24 , it has received the elastic force of the spring  14 , as illustrated in  FIGS. 7A and 7B . Thus, the first housing part  2  is adapted so as not to fall off from the downside of the outer cylindrical body  13  under the connector pre-fitting (connector fitting releasing) condition. 
     In the connector fitting completion position of the inner cylindrical body  5 , the inner cylindrical body  5  is subjected to pressing force from the sensor side connector  30  under condition that the first guide pin  15  abuts on the second horizontal restriction wall  24 , while the second guide pin  16  abuts on the fourth horizontal restriction  28 , as illustrated in  FIGS. 8A and 8B . Thus, in the connector fitting condition, the first housing part  2  is adapted so as not to enter the interior of the outer cylindrical body  13  anymore. 
     The positions of the first vertical restriction wall  21  and the third vertical restriction wall  25  are set so as to correspond to a rotation starting position on the side of the pre-fitting position of the inner cylindrical body  5  and a rotation starting position on the side of the connector fitting completion position, respectively. 
     In a range from the pre-fitting position up to the rotation starting position of the inner cylindrical body  5 , the first guide pin  15  is positioned on one side of the first vertical restriction wall  21  (on the left side in  FIG. 7A ). In the first vertical restriction wall  21 , its lateral face on the one side is formed so as to have a vertical surface, thereby preventing the inner cylindrical body  5  from being rotated on the one side (see  FIGS. 7A and 7C ). In a range from the pre-fitting position up to the rotation enabling position of the inner cylindrical body  5 , the second guide pin  16  is positioned on the other side of the third vertical restriction wall  25  (on the right side in  FIG. 7B ). In the third vertical restriction wall  25 , its lateral face on the other side is formed so as to have a vertical surface, thereby preventing the inner cylindrical body  5  from being rotated on the other side (see  FIGS. 7B and 7D ). That is, the first guide pin  15  and the first vertical restriction wall  21 ; and the second guide pin  16  and the third vertical restriction wall  25  constitute, in combination, a rotation preventing mechanism which stops the rotation of the first housing part  2  between the pre-fitting position and the rotation starting position. 
     The guide rail  20  is a circumferential step surface which is the highest at the initial rotational position of the first guide pin  15  and whose height is gradually lowered as increasing the rotational angle from the initial rotational position. Consequently, when the first housing part  2  returns from the connector fitting completion position to the pre-fitting position due to the elastic force of the spring  14  at the time of releasing the connector fitting, the first guide pin  15  returns to the initial rotational position while being guided by the guide rail  20 . Therefore, the first guide pin  15  and the guide rail  20  constitute a rotational position return mechanism that returns the rotational position of the first housing part  2  to the initial rotational position during a process where the first housing part  2  is moved from the fitting completion position to the pre-fitting position by the elastic force of the spring  14 . 
     In common with the first vertical restriction wall  21  and the first horizontal restriction wall  22 , their respective faces on which the first guide pin  15  abuts in the course of moving from the fitting completion position to the pre-fitting position of the first guide pin  15  are formed to be tapered surfaces. Thus, the first guide pin  15  is adapted so as to be movable over these walls owing to its elastic displacement. In common with the second vertical restriction wall  23  and the third vertical restriction wall  25 , their respective faces on which the second guide pin  16  abuts in the course of moving from the fitting completion position to the pre-fitting position of the second guide pin  16  are formed to be tapered surfaces. Thus, the second guide pin  16  is adapted so as to be movable over these walls owing to its elastic displacement. 
     On the outer circumference of the first housing part  2  on the side of its lower end, there is formed a guide rail face  6  as a rotating direction guide part. The guide rail face  6  is a circumferential rail surface which is the highest at a later mentioned formal fitting rotational position with the second housing part  2  and whose height is gradually lowered as increasing the rotational angle from the fitting rotational position. The guide rail face  6  serves to guide a later mentioned guide rib  32  up to its appropriate fitting rotational position by the time when the first terminal and the second terminal start to come into contact with each other. 
     The first housing part  2  is formed, on its outer circumference, with a straight guide groove  7  which opens at the highest position of the guide rail face  6  and extends vertically upward. 
     The sensor side connector  30  includes a second housing part  31 . The second housing part  31  has a built-in sensor element (not illustrated) located on the side of its lower end. The second housing part  31  is formed, on the outer circumference of the lower end, with a threaded part (not illustrated). By screwing the threaded part into a threaded hole (not illustrated) of a cylinder head (not illustrated), the sensor side connector  30  is mounted to the cylinder head. The second housing part  31  is cylindrical shaped and formed so as to open at its top surface. Inside the second housing part  31 , a second terminal (not illustrated) is disposed so as to face the top surface. The second terminal is provided to pick up an output from the sensor element. 
     The guide rib  32  is formed so as to project from an inner surface of the second housing part  31 . When the tip of the guide rib  32  abuts on the guide rail face  6 , the first housing part  2  is rotated in a manner that the guide rib  32  moves up to the highest position of the guide face  6  by a fitting position previous to the time when the first terminal and the second terminal start to come into contact with each other, so that the first housing part  2  and the second housing part  31  move to the formal fitting rotational positions. Thereafter, the guide rib  32  enters the guide groove  7  to initiate a contact between the first terminal and the second terminal. Then, at the fitting completion position where the guide rib  32  penetrates deep into the guide groove  7 , the first terminal and the second terminal come into contact with each other appropriately. 
     With the above mentioned constitution, as illustrated in  FIG. 1 , the sensor side connector  30  is installed in a cylinder head (not illustrated) and thereafter, the head cover  33  is mounted on the cylinder head. In the head cover  33 , a hole  33   a  is formed at the fitting position of the sensor side connector  30 . The wire harness side connector  1  is fitted into the head cover through the hole  33   a.    
     Here, in the wire harness side connector  1 , the first housing part  2  is located in the pre-fitting position. In the pre-fitting position, as illustrated in  FIGS. 7A and 7B , the first guide pin  15  abuts on the first vertical restriction wall  21  while the second guide pin  16  abuts on third vertical restriction wall  25 , so that normal/reverse rotation between the first housing part  2  and the third housing part  10  is blocked. In this way, it becomes possible to prevent the wires W from being twisted before starting the fitting operation. 
     Next, the fitting operation of the wire harness side connector  1  will be described. On the assumption of setting the orientation (rotating position) of the external connector fitting part  11  to a desired orientation, it is performed to insert the wire harness side connector  1  into the second housing part  31  of the sensor side connector  30  through the hole  33   a  of the head cover  33 . Then, except a situation where the first housing part  2  is inserted into the second housing part  31  at the formal fitting rotational position, the guide rib  32  of the second housing part  31  abuts on an arbitrary part of the guide rail face  6  of the first housing part  2 . 
     When further advancing the fitting from this state, the first housing part  2  receives a reaction force from the guide rib  32 . As the first housing part  2  and the inner cylindrical body  5  are prevented from rotating by the rotation preventing mechanism and instead permitted to move in the axial direction, the first housing part  2  and the inner cylindrical body  5  move in relation to the third housing part  10  toward the fitting completion position while resisting the elastic force of the spring  14 . When the first housing part  2  is moved up to the rotation starting position (each of the first guide pin  15  and the second guide pin  16  moves from the point A up to the point B of  FIGS. 7A and 7B ), then the first housing part  2  becomes rotatable. Then, the first housing part  2  is rotated while being guided by the guide ribs  32  and the guide rail face  6 , the first housing part  2  occupies a rotational position where the guide rib  32  is located at the uppermost position of the guide rail face  6 . In other words, each of the first guide pin  15  and the second guide pin  16  moves from the point B up to point C in  FIGS. 7A and 7B . Thus, the first housing part  2  and the second housing part  31  are brought into the formal fitting rotational positions. 
     Subsequently, when advancing the fitting of the first housing part  2 , the guide rib  32  enters the guide groove  7  and is inserted thereinto up to the completion position where the first housing part  2  is fitted to the second housing part  31 , as illustrated in  FIG. 2 . That is, each of the first guide pin  15  and the second guide pin  16  moves from the point C up to the point D in  FIGS. 7A and 7B . During the process where the guide rib  32  advances in the guide groove  7 , the first terminal and the second terminal start to connect with each other and then, they are brought into an appropriate connecting condition at the fitting completion position. Thus, the fitting operation of the wire harness side connector  1  is completed. 
     Meanwhile, if the fitting between the first housing part  2  and the second housing part  31  is started in their formal fitting rotational positions, then the guide rib  32  directly enters the guide groove  7  without sliding on the guide rail face  6  and is inserted thereinto up to the completion position. In this fitting process, the first housing part  2  is subjected to an external force pressing it upward in the axial direction, so that the first housing part  2  and the third housing part  10  are moved to the fitting completion position. Thus, the third housing part  10  becomes rotatable to the first housing part  2  and thus the second housing part  31 . 
     If it is required to adjust the orientation of the opening of the external connector fitting part  11 , the third housing part  10  is rotated for the adjustment. 
     In order to release the connector fitting, an external force is applied in a direction to make the third housing part  10  apart from the sensor side connector  30 . Then, as the pressing force from the second housing part  31  to the first housing part  2  is released gradually, the first housing part  2  returns from the fitting completion position to the pre-fitting position by the elastic force of the spring  14 . If the first guide pin  15  is located in any position except for the initial rotational position, it abuts on the guide rail  20  other than the uppermost position in this returning process and then returns to the pre-fitting position while being guided by the guide rail  20 . That is, each of the first guide pin  15  and the second guide pin moves from the point E up to point G in  FIGS. 8A and 8B . 
     In the connector device A, as described above, if the fitting orientation of the first housing part  2  is different from the fitting orientation of the second housing part  31 , then the first housing part  2  rotates in relation to the third housing part  10  thereby accomplishing the fitting with the second housing part  31 . Under the resulting connector fitting completion condition, the first terminal and the second terminal are connected to each other. The first housing part  2  is adapted so as to be movable in relation to the third housing part  10  between the pre-fitting position and the fitting completion position in the axial direction and also urged toward the pre-fitting position by the spring  14 . The rotational position return mechanism is provided that returns, when the connector fitting is released, the rotational position of the first housing part  2  to the initial rotational position during the process in which the first housing part  2  is moved from the fitting completion position to the pre-fitting position by the elastic force of the spring. Therefore, in this state, it is possible to execute the connector fitting operation and also possible to prevent the wires W from being twisted to the utmost because the withdrawal of the connector device A from its fitting state brings the wires W into non-twisting condition. 
     The rotation preventing mechanism is provided to prevent the first housing part  2  under the pre-fitting position from rotating in relation to the third housing part  10 . Therefore, even if a rotating force is applied to the first housing part  2  under the connector-fitting releasing condition (i.e. the connector pre-fitting condition), the first housing part  2  does not rotate in relation to the third housing part  10 . Thus, it is possible to prevent the wires W from being twisted, certainly. In the first embodiment, the rotation of the first housing part  2  is blocked between the pre-fitting position and the rotation starting position. Therefore, even if it is attempted to rotate the first housing part  2  while pressing it into the third housing part  10  under condition that the wire harness side connector  1  is in the pre-fitting condition, the first housing part  2  does not rotate absolutely. Accordingly, the twisting of the wires W can be prevented certainly. 
     The rotational position return mechanism includes the guide rail  20  arranged in the inner cylindrical body  5  of the first housing part  2 , and the first guide pin  15  arranged in the outer cylindrical body  13  of the third housing part  10  and also guided by the guide rail  20  during the process in which the first housing part  2  moves from the fitting completion position up to the pre-fitting position in the axial direction. Thus, owing to the simple provision of the guide rail  20  in the first housing part  2  and the first guide pin  15  in the third housing part  10 , it is possible to construct the rotational position return mechanism with ease. Alternatively, the first guide pin  15  may be arranged in the first housing part, provided that the guide rail  20  is arranged in the third housing part  10 . 
     Second Embodiment 
       FIGS. 9 to 16  illustrate a second embodiment. As illustrated in  FIGS. 9 to 11 , a connector device B according to the second embodiment includes a built-in combustion pressure sensor (not illustrated) and is mounted on e.g. an engine head. The connector device B includes the wire harness side connector  1  as the first connector and the sensor side connector  30  as the second connector. 
     The wire harness side connector  1  includes the first housing part  2  having the built-in first terminal (not illustrated), and a third housing part  10  rotatably arranged in relation to the first housing part  2 . On the top of the first housing part  2 , the inner cylindrical body  5  is rotatably arranged so as to partially overlap with the part  2 , coaxially. 
     The third housing part  10  includes the external connector fitting part  11  having the built-in third terminal (not illustrated), the attachment flange part  12 , and the outer cylindrical body  13  connected to a lower portion of the attachment flange part  12 . Different from the first embodiment, the external connector fitting part  11 , the attachment flange part  12 , and the outer cylindrical body  13  are composed of two members. The third terminal and the first terminal are connected to each other through the electrical wires W routed in the outer cylindrical body  13 . Each of the wires W is routed with a surplus length allowing it to be twisted. The external connector fitting part  11  defines, as its fitting direction, a direction generally perpendicular to the fitting direction of the first housing part  2 . Fitted into the external connector fitting part  11  is an external connector (not illustrated) which is connected to a wire harness (not illustrated) on the side of a vehicle body. 
     As illustrated in  FIG. 11 , the inner cylindrical body  5  and the first housing part  2  are accommodated inside the outer cylindrical body  13 . The inner cylindrical body  5  is movable to the outer cylindrical body  13  in the axial direction and also rotatable about its own axis. The first housing part  2  is movable to the inner cylindrical body  5  in the axial direction and also rotatable about its own axis. That is, the inner cylindrical body  5  and the first housing part  2  are rotatable independently of each other. The lower part of the first housing part  2  is exposed from the lower end of the outer cylindrical body  13 . The first housing part  2  is urged against a pre-fitting position by the elastic force of the spring  14  as the urging member housed in the outer cylindrical body  13 . However, the axial moving ranges and rotatable positions of the inner cylindrical body  5  and the first housing part  2  in relation to the outer cylindrical body  13  are restricted by the following structure. The structure will be described below. 
     As illustrated in  FIG. 12 , the outer cylindrical body  13  is provided with the first guide pin  15  and the second guide pin  16  which protrude from the inner surface of the outer cylindrical body  13 . The first guide pin  15  and the second guide pin  16  are arranged in the same rotational positions although they are shifted from each other in the axial direction. With pressing forces applied from the inside, the first guide pin  15  and the second guide pin  16  can withdraw from the inner surface outwardly due to elastic displacements of respective slits s. 
     As illustrated in  FIGS. 11, 14A, and 14B , the inner cylindrical body  5  is provided, in order from its upper position toward the lower position, with: a locking groove  34  which is formed over the entire circumference in the circumferential direction and above which a vertical groove  34   a  is arranged so as to open to the locking groove  34  in a position corresponding to the initial rotational position; an annular horizontal restriction wall  35  formed over the entire circumference in the circumferential direction; a rotation allowable circumferential face  36  also formed over the entire circumference in the circumferential direction; a first rotation allowable concave part  37  arranged over the rotating area of 180 degrees in the circumferential direction; a first guide rail  37   a  formed by a step surface above the first rotation allowable concave part  37 ; and a stop face  37   b  formed by a step surface below the first rotation allowable concave part  37 . 
     In the pre-fitting position of the inner cylindrical body  5 , as illustrated in  FIG. 14A , the inner cylindrical body  5  is subjected to the elastic force of the spring  14 , since the first guide pin  15  is engaged in the locking groove  34  while the second guide pin  16  abuts on the uppermost position of the first guide rail  37   a.  Consequently, the inner cylindrical body  5  is adapted so as not to fall off from the downside of the outer cylindrical body  13  under the connector pre-fitting (connector fitting releasing) condition. 
     In the connector fitting completion position of the inner cylindrical body  5 , as illustrated in  FIG. 14B , the inner cylindrical body  5  is subjected to pressing force from the sensor side connector  30  since the second guide pin  16  abuts on the stop face  37   b.  Thus, in the connector fitting condition, the inner cylindrical body  5  is adapted so as not to enter the interior of the outer cylindrical body  13  anymore. 
     In the pre-fitting position of the inner cylindrical body  5 , the first guide pin  15  gets into the locking groove  34  thereby preventing the inner cylindrical body  5  from being rotated in both directions in relation to the third housing part  10 . That is, in the pre-fitting position, the first guide pin  15  and the locking groove  34  block the rotation of the inner cylindrical body  5  in relation to the third housing part  10 . 
     The first guide rail  37   a  is a generally circumferential step surface which is the highest at the initial rotational position of the first guide pin  15  and whose height is gradually lowered as increasing the rotational angle from the initial rotational position. The first rotation allowable concave part  37  and the first guide rail  37   a  are established to be circumferential surfaces in respective ranges of rotating angles of 90 degrees to the left and right from the initial position as a center. When the first housing part  2  returns from the connector fitting completion position to the pre-fitting position due to elastic force of the spring  14  at the time of releasing the connector fitting, the first guide pin  15  returns to the initial rotational position while being guided by the first guide rail  37   a.  Therefore, the first guide pin  15  and the first guide rail  37   a  return the rotational position of the inner cylindrical body  5  to the initial rotational position during a process where the inner cylindrical body  5  is moved from the fitting completion position to the pre-fitting position by the elastic force of the spring  14 . 
     In the horizontal restriction wall  35 , its faces on which the first guide pin  15  abuts in moving from the pre-fitting completion position to the fitting completion position and vice versa, i.e. from the fitting completion position to the pre-fitting position are formed to be tapered surfaces, respectively. Thus, the first guide pin  15  is adapted so as to be movable over the horizontal restriction wall  35  owing to its elastic displacement. 
     As illustrated in  FIGS. 13A and 13B , the first housing part  2  is provided with a third guide pin  38  which protrudes from the inner surface of the first housing part  2 . With pressing forces applied from the inside, the third guide pin  38  can withdraw from the inner surface outwardly due to its elastic displacement. 
     As illustrated in  FIGS. 14A and 14B , the first housing part  2  is provided with a second rotation allowable concave part  39  arranged over the rotating area of 180 degrees in the circumferential direction, a second guide rail  39   a  formed by a step surface above the second rotation allowable concave part  39 , a stop face  39   b  formed by a step surface below the second rotation allowable concave part  39 , and a locking step face  39   c  formed by an upper side of the second rotation allowable concave part  39 , which is higher than its surroundings. 
     In the pre-fitting position of the first housing part  2 , as illustrated in  FIG. 14A , the first housing part  2  is subjected to elastic force of the spring  14  since the third guide pin  38  abuts on the uppermost position of the second guide rail  39   a.  Consequently, the first housing part  2  is adapted so as not to fall off from the downside of the outer cylindrical body  13  under the connector pre-fitting (connector fitting releasing) condition. 
     In the connector fitting completion position of the first housing part  2 , as illustrated in  FIG. 14B , the first housing part  2  is subjected to pressing force from the sensor side connector  30  since the third guide pin  38  abuts on the stop face  39   b.  Thus, in the connector fitting condition, the first housing part  2  is adapted so as not to enter the interior of the outer cylindrical body  13  anymore. 
     In the pre-fitting position of the first housing part  2 , the third guide pin  38  is positioned on the locking step part  39   c,  which is higher than its surroundings, under condition of abutting on the second guide rail  39   a  thereby preventing the first housing part  2  from being rotated in both directions in relation to the third housing part  10 . The second guide pin  16  is elastically displaced to its outside due to the slits s. As a result, with strong return force of the elastic displacement, the second guide pin comes into pressure contact with the locking step face  39   c  thereby preventing the rotation in both directions. That is, the third guide pin  38  and the locking step face  39   c  block the rotation of the first housing part  2  in relation to the inner cylindrical part  5  in the pre-fitting position. From above, the above mentioned first guide pin  15  and the locking groove  34 ; and the third guide pin  38  and the locking step face  39   c  constitute, in combination, a rotation preventing mechanism which stops the rotation of the first housing part  2  in relation to the third housing part  10  in the pre-fitting position. 
     The second guide rail  39   a  is a circumferential step surface which is the highest at the initial rotational position of the third guide pin  38  and whose height is gradually lowered as increasing the rotational angle from the initial rotational position. The second rotation allowable concave part  39  and the second guide rail  39   a  are established to be circumferential surfaces in respective ranges of rotating angles of 90 degrees to the left and right from the initial position as a center. When the first housing part  2  returns from the connector fitting completion position to the pre-fitting position due to elastic force of the spring  18  at the time of releasing the connector fitting, the third guide pin  38  returns to the initial rotational position while being guided by the second guide rail  39   a.  Therefore, the third guide pin  38  and the second guide rail  39   a  return the rotational position of the first housing part  2  to the initial rotational position during a process where the first housing part  2  is moved from the fitting completion position to the pre-fitting position by the elastic force of the spring  14 . From above, the above mentioned first guide pin  15  and the first guide rail  37   a;  and the third guide pin  38  and the second guide rail  39   a  constitute, in combination, a rotational position return mechanism that returns the first housing part  2  and the inner cylindrical body  5  to the initial rotational position. 
     On the outer circumference of the first housing part  2  on the side of its lower end, the guide rail face  6  is formed as the rotating direction guide part. The guide rail face  6  is a circumferential rail surface which is the highest at a later mentioned formal fitting rotational position with the second housing part  2  and whose height is gradually lowered as increasing the rotational angle from the fitting rotational position. The guide rail face  6  serves to guide the later mentioned guide rib  32  up to its appropriate fitting rotational position by the time when the first terminal and the second terminal start to come into contact with each other. 
     The first housing part  2  is formed, on its outer circumference, with the straight guide groove  7  which opens at the highest position of the guide rail face  6  and extends vertically upward. 
     The sensor side connector  30  includes a second housing part  31 . The second housing part  31  has a built-in sensor element (not illustrated) located on the side of its lower end. The second housing part  31  is formed, on the outer circumference of the lower end, with a threaded part (not illustrated). By screwing the threaded part of the second housing part  31  into a threaded hole (not illustrated) of a cylinder head (not illustrated), the sensor side connector  30  is mounted to the cylinder head. The second housing part  31  is cylindrical shaped and formed so as to open at its top surface. The second terminal (not illustrated) is arranged in the second housing part  31 . The second terminal is provided to pick up an output from the sensor element. 
     The guide rib  32  is formed so as to project from an inner surface of the second housing part  31 . When the tip of the guide rib  32  abuts on the guide rail face  6 , the first housing part  2  is rotated in a manner that the guide rib  32  moves up to the highest position of the guide face  6  by a fitting position previous to the time when the first terminal and the second terminal start to come into contact with each other, so that the first housing part  2  and the second housing part  31  move to the formal fitting rotational positions. Thereafter, the guide rib  32  enters the guide groove  7  to initiate a contact between the first terminal and the second terminal. Then, at the fitting completion position where the guide rib  32  penetrates deep into the guide groove  7 , the first terminal and the second terminal come into contact with each other appropriately. 
     With the above mentioned constitution, as illustrated in  FIG. 10A , the sensor side connector  30  is installed in a cylinder head (not illustrated) and thereafter, the head cover  33  is mounted on the cylinder head. In the head cover  33 , the hole  33   a  is formed at the fitting position of the sensor side connector  30 . The wire harness side connector  1  is fitted into the head cover through the hole  33   a.    
     Here, in the wire harness side connector  1 , the first housing part  2  is located in the pre-fitting position. In the pre-fitting position, as illustrated in  FIG. 14A , the first guide pin  15  gets into the locking groove  34  while the third guide pin  30  is located on the locking step face  39   c,  so that normal/reverse rotation between the first housing part  2  and the third housing part  10  is blocked. In this way, it becomes possible to prevent the wires W from being twisted before starting the fitting operation. 
     Next, the fitting operation of the wire harness side connector  1  will be described. On the assumption of setting the orientation (rotating position) of the external connector fitting part  11  to a desired orientation, it is performed to insert the wire harness side connector  1  into the second housing part  31  of the sensor side connector  30  through the hole  33   a  of the head cover  33 . Then, except a situation where the first housing part  2  is inserted into the second housing part  31  at the formal fitting rotational position, the guide rib  32  of the second housing part  31  abuts on an arbitrary part of the guide rail face  6  of the first housing part  2   
     When further advancing the fitting from this state, an upward pressing force acts on the first housing part  2  by a reaction force from the guide rib  32 , so that the first housing part  2  moves in relation to the third housing part  10  toward the fitting completion position while resisting the elastic force of the spring  14 . Consequently, the first guide pin  15  climbs over the horizontal restriction wall  35  and gets into the rotation allowable circumferential face  36 . The second guide pin  16  is positioned away from the first guide rail  37   a  in the first rotation allowable concave part  37 . Further, the third guide pin  38  is located off the locking step face  39   c  of the second rotation allowable concave part  39 . As a result, the first housing part  2  becomes rotatable to the inner cylindrical body  5 , while the inner cylindrical body  5  becomes rotatable to the third housing part  10 . Then, the first housing part  2  is rotated while being guided by the guide rail face  6  and the guide ribs  32 , and subsequently, the first housing part  2  occupies a rotational position where the guide rib  32  is located at the uppermost position of the guide rail face  6 . Thus, the first housing part  2  and the second housing part  31  are brought into the formal fitting rotational positions. 
     Subsequently, when advancing the fitting of the first housing part  2 , the guide rib  32  enters the guide groove  7  and is inserted thereinto up to the completion position where the first housing part  2  is fitted to the second housing part  31 , as illustrated in  FIG. 10B . During the process where the guide rib  32  advances in the guide groove  7 , the first terminal and the second terminal start to connect with each other and then, they are brought into an appropriate connecting condition at the fitting completion position. Thus, the fitting operation of the wire harness side connector  1  is completed. 
     Meanwhile, if the fitting between the first housing part  2  and the second housing part  31  is started in the formal fitting rotational positions, then the guide rib  32  directly enters the guide groove  7  without sliding on the guide rail face  6  and is inserted thereinto up to the completion position. In this fitting process, the first housing part  2  is subjected to an external force pressing it upward in the axial direction, so that the first housing part  2  and the third housing part  10  are moved to the fitting completion position. Thus, the third housing part  10  becomes rotatable to the first housing part  2  and thus the second housing part  31 . 
     If it is required to adjust the orientation of the opening of the external connector fitting part  11 , the third housing part  10  is rotated for the adjustment. 
     In order to release the connector fitting, an external force is applied in a direction to make the third housing part  10  apart from the sensor side connector  30 . Then, as the pressing force from the second housing part  31  to the first housing part  2  is released gradually, the first housing part  2  returns from the fitting completion position to the pre-fitting position by the elastic force of the spring  14 . The first guide pin  15  climbs over the horizontal vertical wall  35  and returns to a position on a level with the locking groove  34  in this returning process. The second guide pin  16 , when it is located in any position except for the initial rotational position, abuts on the first guide rail  37   a  other than the uppermost position in this returning process, so that the inner cylindrical body  5  returns to the pre-fitting position while being guided by the guide rail  20 . The third guide pin  38 , when it is located in any position except for the initial rotational position, abuts on the second guide rail  39   a  other than the uppermost position in this returning process, so that the first housing part  2  returns to the pre-fitting position while being guided by the second guide rail  39   a.  That is, the first housing part  2  and the inner cylindrical body  5  together return to the pre-fitting positions while rotating toward the initial rotational positions. 
     In the connector device B, as described above, if the fitting orientation of the first housing part  2  is different from the fitting orientation of the second housing part  31 , then the first housing part  2  rotates in relation to the third housing part  10  thereby accomplishing the fitting with the second housing part  31 . Under the resulting connector fitting completion condition, the first terminal and the second terminal are connected to each other. The first housing part  2  is adapted so as to be movable in relation to the third housing part  10  between the pre-fitting position and the fitting completion position in the axial direction and also urged toward the pre-fitting position by the spring  14 . The rotational position return mechanism is provided that returns, when the connector fitting is released, the rotational position of the first housing part  2  to the initial rotational position during the process in which the first housing part  2  is moved from the fitting completion position to the pre-fitting position by the elastic force of the spring. Therefore, in this state, it is possible to execute the connector fitting operation and also possible to prevent the wires W from being twisted to the utmost because the withdrawal of the connector device B from its fitting state brings the wires W into non-twisting condition. 
     The rotation preventing mechanism is provided to prevent the first housing part  2  under the pre-fitting position from rotating in relation to the third housing part  10 . Therefore, even if a rotating force is applied to the first housing part  2  under the connector-fitting releasing condition (i.e. the connector pre-fitting condition), the first housing part  2  does not rotate in relation to the third housing part  10 . Thus, it is possible to prevent the wires W from being twisted, certainly. 
     The rotational position return mechanism includes the second guide pin  16  provided in the third housing part  10 , the first guide rail  37   a  provided in the inner cylindrical body  5 , the third guide pin  38  provided in the inner cylindrical body  5 , and the second guide rail  39   a  provided in the first housing part  2 . Thus, as the first housing part  2  and the inner cylindrical body  5  rotate in relation to the third housing part  10  respectively, the rotational range to the third housing part  10  is allocated to the first housing part  2  and the inner cylindrical body  5 , thereby allowing respective rotational ranges of the first housing part  2  and the inner cylindrical body  5  to be reduced. Therefore, if the rotational range required for the first housing part  2  in relation to the third housing part  10  is 180 degrees on the right and left sides, the first guide rail  37   a  and the second guide rail  39   a  may be formed between the third housing part  10  and the inner cylindrical part  5  and between the inner cylindrical part  5  and the first housing part  2  respectively, with the rotational range of 90 degrees on the right and left sides with respect to each guide rail. Alternatively, the first guide rail  37   a  may be arranged in the third housing part  10 , provided that the second guide pin  16  is arranged in the inner cylindrical body  5 . Or, the second guide rail  39   a  may be arranged in the inner cylindrical body  5 , provided that the third guide pin  38  is arranged in the first housing part  2 . 
     Modification of Second Embodiment 
       FIG. 17  illustrates a modification of the inner cylindrical body  5 A of the second embodiment. The inner cylindrical body  5 A of the modification is provided, in vertically symmetric positions, with the first rotation allowable concave parts  37 , the first guide rails  37   a,  the stop faces  37   b,  and the third guide pins  38 . 
     With use of the inner cylindrical body  5 A according to the modification, it is possible to assemble the inner cylindrical body  5 A from either of upper and lower directions, offering improved assembling workability. 
     In connection, if the first guide rails  37   a  are provided in the third housing part  10 , the second guide pins  16  are arranged in vertically symmetric positions of the inner cylindrical body  5 A, respectively. If the third guide pins  38  are provided in the first housing part  2 , the second guide rails  39   a  are arranged in vertically symmetric positions of the inner cylindrical body  5 A, respectively. 
     Modifications Etc. of Respective Embodiments 
     In common with the first embodiment and the second embodiment, the guide rail face  6  is formed in the first housing part  2  of the wire harness side connector  1 , while the guide rib  32  is formed in the second housing part  31  of the sensor side connector  30 . To the contrary, the guide rib  32  may be formed in the first housing part  2  of the wire harness side connector  1 , provided that the guide rail face  6  is formed in the second housing part  31  of the sensor side connector  30 . 
     Although each of the connector device A according to the first embodiment and the connector device B according to the second embodiment is equipped with the combustion pressure sensor element (not illustrated) integrally and further installed in the cylinder head of the engine, the present application is not limited to these arrangements. The present application is applicable to a connector device, for example, whether or not a sensor element is present and also applicable to even a connector device integrally equipped with a component other than the sensor element. Although the connector device of the present application is effective in a situation that a counterpart side housing part cannot be identified visually, the present application is available in even a situation that the counterpart side housing part is visible. That is, it is possible to perform the fitting operation without giving consideration to the orientation (rotational position) of the counterpart side housing part, with ease.