JP2002228484A - Rotation sensor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve mass productivity at a low cost by largely reducing a manufacturing man-hour (manufacturing time) and to remarkably enhance reliability and homogeneity (quality) by eliminating necessity of a potting material. SOLUTION: A rotation sensor 1 comprises a coil body B having a bobbin 2 and a terminal support 3 including connecting recesses 4 adjacent to the bobbin 2, lead terminals 5, 6 inserted to the support 3 and opposed at their one ends 5a, 6a to the recesses 4, a coil 1 wound on the bobbin 2 and having wire ends Wx, Wy connected to the one ends 5a, 6a, and an overmold M provided by forming the body B. When the sensor 2 is constituted, the sensor 2 comprises a protective cap 8 having locking parts 9p, 9q covering the recesses 4 and locking the support 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation sensor suitable for use as a vehicle speed sensor for detecting the rotation speed of a tone wheel, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a rotation sensor for detecting the rotation speed of a tone wheel, for example, a rotation sensor 50 shown in FIG. 8 is known.

The rotation sensor 50 includes a coil body 51 including a bobbin portion 52 and a terminal support portion 53 having a connection concave portion 54 adjacent to the bobbin portion 52. The coil body 51 is inserted into the coil concave portion 51 in the connection concave portion 54. The wire ends 57s, 57t of the coil 57 wound around the bobbin 52 are connected to the ends 55a, 56a of the pair of lead terminals 55, 56, respectively. The entire body of the coil body 51 assembled by the
8 covered. In this case, at the time of the secondary molding, the high-pressure synthetic resin enters the connection concave portion 54 and the wire end 57.
In order to cause a problem of disconnection of s and 57t, the connection recess 53 is filled with a silicon-based potting material to prevent disconnection of the wire ends 56s and 56t. Numeral 59 indicates an O-ring, and numeral 60 indicates a fusion rib for sealing.

[0004]

However, the above-described conventional rotation sensor 50 and the method of manufacturing the same have the following problems.

[0005] First, a potting step of filling the connection recess 54 with a potting material and drying it is necessary, which leads to a decrease in mass productivity and an increase in manufacturing cost due to an increase in the number of manufacturing steps (manufacturing time).

[0006] Secondly, the use of the potting material causes inconveniences, that is, a reduction in reliability due to the generation of an unfilled portion (pinhole) of the potting material and a reduction in homogeneity of the potting portion.

[0007] The present invention has solved the problems existing in the prior art, and can significantly reduce the number of man-hours (manufacturing time) to improve mass productivity and reduce costs. It is an object of the present invention to provide a rotation sensor and a method for manufacturing the rotation sensor, which can dramatically improve reliability and homogeneity (quality) without using any material.

[0008]

The rotation sensor 1 according to the present invention comprises a coil body B comprising a bobbin 2 and a terminal support 3 having a connection recess 4 adjacent to the bobbin 2. One end portions 5a and 6a of the lead terminals 5 and 6 inserted into the terminal support portion 3 face the connection concave portion 4, and the wire ends of the coil portion 7 wound around the bobbin portion 2 at the one end portions 5a and 6a. Connect Wx and Wy,
This coil body B is subjected to secondary molding to form an overmold M
When the rotation sensor is provided, the locking portions 9p, which cover the connection recess 4 and are locked to the terminal support portion 3, are provided.
A protective cap 8 having 9q is provided.

In this case, according to a preferred embodiment, the coil body B is formed in a cylindrical shape, the connection concave portion 4 is provided in the outer peripheral portion 3s of the terminal support portion 3, and the protective cap 8 is provided.
Can be formed integrally with each other in an arc shape having a predetermined width to cover the connection concave portion 4, and provided with locking claws 9 p and 9 q which are locked to the terminal support portions 3 at both ends in the circumferential direction. The coil end B has a wire end W between the bobbin 2 and the connection recess 4.
Notched guide slits 11x and 11y for passing x and Wy
And the protective cap 8 can be formed to have a predetermined width covering the guide slits 11x and 11y. Further, the protective cap 8 is provided on its inner surface with a regulating protrusion 12 which engages with the inner surface of the connection concave portion 4 and regulates the position of the terminal support 3 in the axial direction. It is possible to provide a regulating slit portion 14 which is engaged with the engaging portion 13 formed inside the connection concave portion 4 to regulate the position in the circumferential direction and the radial direction of the terminal support portion 3. Note that the terminal support 3 has a bobbin 2 near the connection recess 4.
A guide projection 15 that engages with the regulating slit 14 is provided on the outer peripheral portion 3 s on the opposite side to the main body. Is desirably provided. Also,
The coil body B may be provided with a ring-shaped fusion rib portion 17 protruding radially from the front end outer peripheral surface and / or a ring-shaped fusion rib portion 18 protruding rearward from the rear end surface. Further, the coil body B has an upper surface and a lower surface,
Positioning portions 19u positioned in the X, Y and Z directions,
19d, positioning portions 19p and 19q positioned in the X and Y directions can be provided on the left and right surfaces.

On the other hand, the method of manufacturing the rotation sensor 1 according to the present invention comprises a coil body B comprising a bobbin part 2 and a terminal support part 3 having a connection concave part 4 adjacent to the bobbin part 2. To the ends 5a and 6a of the lead terminals 5 and 6 inserted into the terminal support 3 and connect the wire ends Wx and Wy of the coil 7 wound around the bobbin 2 to the ends 5a and 6a. In addition, when the coil body B is secondarily formed to provide the overmolded portion M, a protective cap 8 that covers the connection concave portion 4 and has locking portions 9p and 9q for locking to the terminal support portion 3 is prepared. Then, after the protective cap 8 is attached to the terminal support portion 3, the overmold portion M is provided by secondary molding.

In this case, according to a preferred embodiment, after the protective cap 8 is engaged with the outer peripheral portion 3s other than the connection concave portion 4 in the terminal support portion 3, the protective cap 8 is displaced toward the connection concave portion 4 side. The guide protrusion 15 can be attached to a position covering the connection recess 4, and at this time, a guide projection 15 is provided on the outer peripheral portion 3 s of the terminal support 3 near the connection recess 4 and opposite to the bobbin 2. When the protective cap 8 is provided, the protective cap 8 can be engaged with the guide projection 15.

[0012]

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the configuration of the coil body B used in the rotation sensor 1 according to the present embodiment will be described with reference to FIGS.

The coil body B is integrally formed of a synthetic resin (for example, a polyamide resin) so as to be entirely cylindrical. The coil body B has a bobbin 2 and a terminal support 3 provided at an end of the bobbin 2. In this case, the bobbin part 2 has a cylindrical bobbin main body part 2m and one barrier part 2b provided at one end of the bobbin main body part 2m. Are provided integrally. Therefore, the terminal support portion 3 also serves as the other barrier portion in the bobbin portion 2.

On the other hand, a pole piece insertion hole 21 and a magnet accommodating hole 22 are provided inside the terminal support portion 3, and a connection recess 4 is provided on an outer peripheral portion 3 s of the terminal support portion 3. The terminal support portion 3 has a pair of lead terminals 5 and 6 embedded by insert molding. One end portions 5a and 6a of the lead terminals 5 and 6 project into the connection recess 4 and are connected to the lead terminals 5 and 6, respectively. The other end portions 5b, 6b of 6 protrude toward the other end side (rear end side) of the terminal support portion 3. A pair of notched guide slits 11x and 11y are provided between the bobbin portion 2 and the connection concave portion 4, and an insulating wall portion 23 is provided in the center of the inside of the connection concave portion 4. This insulating wall portion 23 also serves as an engaging portion 13 described later.

Thus, when assembling the coil body B, the wire W is wound around the bobbin portion 2 to manufacture the coil portion 7, and the pair of wire ends Wx and Wy derived from the coil portion 7 are respectively connected. The lead is guided to the connection recess 4 through the corresponding guide slits 11x and 11y, and is connected to one ends 5a and 6a of the lead terminals 5 and 6, respectively.
In this case, the wire ends Wx and Wy are connected to each other by soldering after being entangled with the upright end portions 5a and 6a, and thereafter the connection end portions 4a and 6a are bent by bending the one end portions 5a and 6a. Housed inside. Thereby, the assembled coil body B can be obtained. And the coil body B assembled in this way
Is overmolded by secondary molding. By the way, in the secondary molding, conventionally, the connecting recess 4 was filled with the potting material as described above, but this embodiment (the present invention)
Then, the protective cap 8 is attached instead of the potting material.

Next, the structure and mounting method of the protective cap 8 will be specifically described with reference to FIGS.

As shown in FIGS. 4 and 5, the entire protective cap 8 is integrally formed of a synthetic resin. The protective cap 8 includes the connection recess 4 and the guide slits 11x and 11x.
4, has a predetermined width, and is formed in an arc shape as shown in FIG. 4, and locking claws 9p and 9q for locking to the terminal support portion 3 are provided at both ends in the circumferential direction. Therefore, on the both sides in the circumferential direction of the connection concave portion 4 in the terminal support portion 3, locked portions 24p and 24q to which the locking claws 9p and 9q are locked are provided. In this case, as shown in FIG. 5, the portions of the protective cap 8 covering the guide slits 11x and 11y are formed to be thin via the stepped portions 31 so as to prevent the portions from expanding radially outward as much as possible. Thus, the guide slits 11x and 11y become holes by being covered with the protective cap 8, so that the wire ends Wx and Wy passing through the guide slits 11x and 11y can be reliably protected.

The protective cap 8 is required to be as thin as possible due to the limitation of the thickness when the coil body B is overmolded, but can withstand high-pressure synthetic resin during the secondary molding. Since strength is required, a material (for example, polyamide-based resin) meeting both of these requirements is selected, and the following characteristic shape is provided.

First, on the inner surface of the protective cap 8, there is provided a regulating protrusion 12 which is engaged with the inner surface of the connection concave portion 4 to regulate the position of the terminal supporting portion 3 in the axial direction. Engaging portion 13 formed inside connection concave portion 4
A regulating slit portion is provided which engages with the (insulating wall portion) and regulates the position of the terminal supporting portion in the circumferential and radial directions.
Thickness reinforcing portions 16p and 16q are provided on the outer surface of the protective cap 8 other than the restricting slit portion 14 to secure strength enough to withstand high-pressure synthetic resin. With such a shape, the protection cap 8 can expand the locking portions 9p and 9q to both sides as shown by the phantom line in FIG. 4, but the elasticity at this time is the regulating slit portion 14 which is the thinnest portion. Is secured by the part. However, after mounting, as shown in FIG. 1, the engaging portion 13 engages (fits) with the regulating slit portion 14, and the strength of the portion of the regulating slit portion 14 is ensured. On the other hand, a guide projection 15 for guiding the regulating slit 14 of the protective cap 8 is provided on the outer peripheral portion 3s of the terminal support portion 3 near the connection concave portion 4 and opposite to the bobbin portion 2. .

Thus, the protective cap 8 can be mounted on the coil body B according to the procedure shown in FIG. First, the protective cap 8 indicated by a solid line in FIG. 6 is engaged with the outer peripheral portion 3s of the terminal support portion 3 located next to the connection concave portion 4 from the direction of the arrow D1. At this time, the regulating slit portion 14 of the protective cap 8 is engaged with the guide projection 15. Then, the protective cap 8 is pushed in the direction of the arrow D2, which is the axial direction, to slide and displace the protective cap 8. in this case,
Since the guide projection 15 has both the positioning function with respect to the protective cap 8 and the guide rail function, the protective cap 8 can be reliably and smoothly guided. In addition, since the protective cap 8 expands outward due to elasticity and has a semicircle or a shape larger than the semicircle, the protective cap 8 is displaced, and the restricting slit portion 14 is moved to the guide protrusion 15. From the protective cap 8
Is elastically displaced in the direction of arrow D3, so that the mounting is automatically performed. At this time, the locking portions 9p and 9q are locked by the locked portions 24p and 2q.
4q, and the shape of the locked portions 24p, 24q prevents the protective cap 8 from coming off. Such a mounting process may be performed by a fully automatic process or a manual process.

As a result, the protection cap 8 has its regulating projection 12 provided on its inner surface engaged with the inner surface of the connection recess 4 to regulate the position of the terminal support 3 in the axial direction. Since the regulating slit portion 14 provided is engaged with the engaging portion 13 formed inside the connection concave portion 4 to regulate the position in the circumferential direction and the radial direction of the terminal support portion 3, the protective cap 8 is formed.
Accordingly, the connection concave portion 4 can be reliably covered without increasing the outer shape of the terminal support portion 3. Further, by such a mounting method, the wire end W in the connection concave portion 4 is formed.
The protection cap 8 can be securely and smoothly mounted while avoiding disconnection of x and Wy.

If the protective cap 8 is attached,
The coil body B is secondarily formed to provide the overmold M. In this case, first, the pole piece 33 and the magnet 34 are accommodated inside the coil body B, and the cables 35a, 35b are connected to the other ends 5b, 6b of the lead terminals 5, 6.
35b are respectively connected. Thereby, the pole piece 33 is housed in the inside of the bobbin part 2 and the pole piece insertion hole 21 of the terminal support part 3, a part of which protrudes from the tip of the bobbin part 2, and the magnet 34 is the magnet of the terminal support part 3. It is accommodated in the accommodation hole 22. Thereafter, the final rotation sensor 1 can be obtained by setting it in a secondary mold and injecting and filling a synthetic resin (for example, a polyamide resin). In this case, a synthetic resin having a higher melting point than the coil body B is used for the overmold M. Thereby, resin fusion (sealing) can be performed reliably. In the case where a resin having a low curing speed after filling the mold is used, the synthetic resin of the overmold portion M and the synthetic resin of the coil body B may have the same melting point. FIGS. 3 and 7 show the rotation sensor 1 after the secondary molding, and M denotes the overmolded part after the secondary molding.

By the way, positioning portions 19u, 19 for ensuring the positioning during the secondary molding are provided on the coil body B.
d, 19p and 19q are provided. Positioning part 19u,
19d, 19p, and 19q are provided at equal intervals in the circumferential direction, and are respectively positioned by positioning portions provided in the secondary mold. In this case, as shown in FIG. 7, the positioning portion 19u provided on the upper surface of the coil body B and the positioning portion 19d provided on the lower surface of the coil body B (FIG. 6) are X, Y and Z
The positioning portion 19p provided on the right surface of the coil body B and the positioning portion 19q (FIG. 2) provided on the left surface of the coil body B are positioned only in the X and Y directions, and are positioned in the Z direction. Therefore, if the mold including the upper mold and the lower mold is opened, the molded article (the rotation sensor 1) after the secondary molding can be easily taken out in the Z direction.

The coil body B according to the present embodiment is different from the conventional coil body 51 (FIG. 8) in the diameter from the outer peripheral surface of the barrier portion 2b of the bobbin 2 (the outer peripheral surface at the front end of the coil body B). A single fusion rib portion 17 protruding in the direction and a single fusion rib portion 18 projecting rearward from the rear end of the terminal support 3 are newly provided. Each of the fusion rib portion 17 and the fusion rib portion 18 is formed in a ring shape and has a thin tip. Therefore, at the time of the secondary molding, the tip is melted and fused to the overmold portion M, and sealing is performed. By providing such a fusion rib portion 17, the fusion rib portion 60 projecting forward provided on the conventional bobbin portion 52 (FIG. 8) is provided.
Is unnecessary, so that the coil portion 7 can be positioned relatively forward, and the magnetic performance can be improved. Further, by providing the fusion rib portion 18, the O-ring 59 and the O-ring 59 provided in the conventional coil body 51 (FIG. 8) are provided.
Since the ring groove of the pole piece on which the ring 59 is mounted can be made unnecessary, flux leakage can be eliminated and magnetic characteristics can be improved.

As shown in FIG. 3, such a rotation sensor 1 can be used so as to face a peripheral portion Rr of a gear-shaped tone wheel R. The tone wheel R is formed of a magnetic material, and has a concave portion Rra..
b and the convex portions Rrb alternately approach the tip of the pole piece 33 due to the rotation. As a result, the magnetic flux generated from the pole piece 33 changes in accordance with the rotation of the tone wheel R.
Since the voltage is detected as a voltage induced in the coil unit 7, the rotation speed (the number of rotations) of the tone wheel R can be detected based on a change in the voltage. Therefore, such a rotation sensor 1 is suitable for use as a vehicle speed sensor or the like provided in an ABS (anti-lock braking system) of an automobile.

Therefore, according to the rotation sensor 1 according to the present embodiment, since the protection cap 8 that can be easily and securely mounted is provided, the conventional potting step of filling and drying the potting material is unnecessary, and the number of manufacturing steps (manufacturing) is reduced. Time) can be greatly reduced, thereby improving mass productivity and reducing costs. Further, since no potting material is used, reliability and homogeneity (quality) can be dramatically improved.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment,
The configuration, shape, material, quantity, etc. of the details can be arbitrarily changed, added, or deleted without departing from the gist of the present invention. For example, the case where the coil body B of the embodiment is constituted by the bobbin part 2 and the terminal support part 3 having the connection concave part 4 adjacent to the bobbin part 2 is shown, but even if other members or functions are added. Good. Also, the case where a pair of lead terminals 5 and 6 are provided on the terminal support 3 is shown, but the number is arbitrary. Furthermore, the shape of the protective cap 8 is arbitrary, that is, it suffices that the protective cap 8 covers at least the connection concave portion 4 and includes locking portions 9x and 9y for the coil body B. Therefore, the guide slits 11x and 11y include holes.

[0029]

As described above, the rotation sensor according to the present invention is provided with the protective cap which covers the connection recess provided in the terminal support and has the locking portion which is locked to the terminal support. In the method for manufacturing a rotation sensor according to the present invention, after covering the connection recess by attaching the protective cap to the terminal support,
Since the overmold portion is provided by performing the secondary molding, the following remarkable effects are obtained.

(1) Since the conventional potting step of filling and drying the potting material is not required, the number of manufacturing steps (manufacturing time) can be greatly reduced, and mass productivity can be improved and cost can be reduced.

(2) Since no potting material is used, reliability and homogeneity (quality) can be dramatically improved.

(3) According to a preferred embodiment, a notch-shaped guide slit for guiding a wire end is provided between the bobbin portion and the connection concave portion in the terminal support portion, and a protective cap is provided to cover the guide slit. If configured in a shape having a width, without making the guide slit a hole,
The end of the wire passing through the guide slit can be reliably protected.

(4) According to a preferred embodiment, a regulating projection is provided on the inner surface of the protective cap so as to be engaged with the inner surface of the connection recess to regulate the position of the terminal support in the axial direction. A restricting slit portion which is engaged with an engaging portion formed inside the connection concave portion and is regulated in position in a circumferential direction and a radial direction of the terminal support portion. If the thick reinforcing portion is provided, the connection concave portion can be surely covered with the protective cap, and both appropriate elasticity and necessary strength of the protective cap can be secured.

(5) According to a preferred embodiment, the terminal supporting portion is provided with a guide projecting portion which engages with the regulating slit portion on the outer peripheral portion near the connection concave portion and opposite to the bobbin portion. If it is provided, the occurrence of disconnection or the like can be avoided, and the protective cap can be securely and smoothly mounted.

(6) According to the preferred embodiment, if the coil body is provided with a ring-shaped fusion rib portion projecting radially from the outer peripheral surface of the front end, the coil portion can be positioned relatively forward. Therefore, the magnetic performance can be improved, and if the coil body is provided with a ring-shaped fusion rib protruding rearward from the rear end face, the O-ring or the O-ring provided in the conventional coil body can be provided. Since the ring groove of the pole piece to be mounted can be made unnecessary, magnetic properties can be improved by eliminating flux leakage.

(7) According to a preferred embodiment, positioning portions for positioning in the X, Y, and Z directions are provided on the upper and lower surfaces of the coil body, and the left and right surfaces are provided with:
By providing a positioning part that is positioned in the X and Y directions,
The molded article (rotation sensor) after the secondary molding can be easily taken out in the Z direction while reliably performing the positioning during the secondary molding.

[Brief description of the drawings]

FIG. 1 is a cross-sectional front view (a cross-sectional view taken along line AA in FIG. 2) of a rotation sensor according to a preferred embodiment of the present invention;

FIG. 2 is a plan view of a coil body provided in the rotation sensor.

FIG. 3 is a cross-sectional plan view of the rotation sensor,

FIG. 4 is a rear view of a protective cap provided in the rotation sensor;

FIG. 5 is a sectional side view of a protective cap provided in the rotation sensor.

FIG. 6 is an explanatory view when a protective cap is attached to a coil body provided in the rotation sensor,

FIG. 7 is an external perspective view showing a part of the rotation sensor;

FIG. 8 is a partial cross-sectional plan view of a rotation sensor according to the related art,

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotation sensor 2 Bobbin part 3 Terminal support part 3s Circumferential surface part of terminal support part 4 Connection concave part 5 ... Lead terminal 5a ... One end part of lead terminal 7 Coil part 8 Protective cap 9p ... Locking part 11x ... Guide slit 12 Regulation Projection part 13 Engagement part 14 Restriction slit part 15 Guide projection part 16p ... Thick reinforcement part 17 Fusion rib part 18 Fusion rib part 19u ... Positioning part 19p ... Positioning part B Coil body M Overmold part Wx Wire end Wy Wire end

Claims (12)

[Claims] 1. A coil body comprising a bobbin portion and a terminal support portion having a connection concave portion adjacent to the bobbin portion, wherein one end of a lead terminal inserted into the terminal support portion faces the connection concave portion. A wire end of the coil portion wound around the bobbin portion is connected to the one end portion, and the connection concave portion is covered in a rotation sensor provided with an overmold portion by secondary forming the coil body. A rotation sensor comprising a protective cap having a locking portion for locking to the terminal support. 2. The coil body is formed in a cylindrical shape.
The connection recess is provided on the outer periphery of the terminal support, and the protection cap is integrally formed in an arc shape having a predetermined width to cover the connection recess, and is connected to the terminal support at both ends in the circumferential direction. The rotation sensor according to claim 1, further comprising a locking claw that stops. 3. The coil body has a notched guide slit for passing the wire end between the bobbin portion and the connection concave portion, and the protective cap has a predetermined width covering the guide slit. The rotation sensor according to claim 1, further comprising: 4. The protection cap according to claim 2, wherein an inner surface of the protective cap has a regulating projection that engages with an inner surface of the connection recess to regulate the position of the terminal support in the axial direction. Rotation sensor. 5. A restricting slit in which the protective cap is engaged with an engaging portion formed inside the connecting concave portion on the restricting projection, and a position of the protective cap is restricted in a circumferential direction and a radial direction of the terminal supporting portion. The rotation sensor according to claim 4, further comprising a portion. 6. The terminal supporting portion is provided on an outer peripheral portion near the connection concave portion and on an opposite side to the bobbin portion.
The rotation sensor according to claim 5, further comprising a guide protrusion that engages with the restriction slit. 7. The rotation sensor according to claim 6, wherein the protective cap has a thickness reinforcing portion at a portion other than the restriction slit portion. 8. The coil body has a ring-shaped fusion rib protruding radially from a front end outer peripheral surface and / or a ring-shaped fusion rib protruding rearward from a rear end surface. The rotation sensor according to claim 2. 9. The coil body has X, Y on upper and lower surfaces.
The rotation sensor according to claim 1, further comprising a positioning portion positioned in the X and Y directions, and a positioning portion positioned in the X and Y directions. 10. A coil body comprising a bobbin portion and a terminal support portion having a connection concave portion adjacent to the bobbin portion, wherein one end of a lead terminal inserted into the terminal support portion faces the connection concave portion. In the method for manufacturing a rotation sensor in which the wire end of the coil portion wound around the bobbin portion is connected to the one end portion and the coil body is secondarily formed to provide an overmold portion, the connection concave portion is covered. A protective cap having a locking portion for locking to the terminal support portion is prepared, and after attaching the protective cap to the terminal support portion, the overmold portion is formed by secondary molding. Manufacturing method of rotation sensor. 11. After the protective cap is engaged with an outer peripheral portion of the terminal support portion other than the connection concave portion,
The method for manufacturing a rotation sensor according to claim 10, wherein the rotation sensor is mounted at a position covering the connection recess by displacing the connection recess. 12. A guide projection is provided on an outer peripheral portion of the terminal supporting portion near the connection recess and opposite to the bobbin portion, and the protective cap is attached when the protective cap is mounted. The method according to claim 11, wherein the rotation sensor is engaged with the guide protrusion.