JP2003065363A - Electromagnetic pilot type clutch system and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic pilot type clutch system where in order to adjust variation in transmitted torque, there is no need for preparing a plurality of yokes in which a distance (a length of a magnetic path) between an inside peripheral surface of the yoke and an outside peripheral surface of a rear housing portion with a small diameter or a distance (the length of the magnetic path) between an outside peripheral surface of the yoke and an inside peripheral surface of a rear housing portion with a large diameter is varied, so that the variation in the transmitted torque is adjusted without replacing the yoke, and to provide manufacturing method thereof. SOLUTION: The yoke is fixed to a rear case in which rotating members are supported in a rotatable manner. In either a cross-sectional area of an inside magnetic path where the rear housing portion with the small diameter and the inside peripheral surface of the yoke are opposed to each other or that of an outside magnetic path where the rear housing portion with the large diameter and the outside peripheral surface of the yoke are opposed to each other, at least one cross-sectional area of them has a shape changing by movement of the yoke in a rotating axial direction. The rear case is fixed after its position has been adjusted in a rotating axial direction so that the variation in the torque transmitted, in relation to electric current fed to an electromagnet, between a rotating axis and the rotating member can be within the allowable range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic pilot type clutch device and a method for manufacturing the same.

[0002]

2. Description of the Related Art The transmission torque of an electromagnetic pilot clutch device for transmitting the rotational power of an engine to a drive wheel varies with the magnetic flux circulating through a yoke, a small-diameter rear housing part, an armature, and a large-diameter rear housing part with an electromagnet as a base point. Cause The variation of the transmission torque due to the magnetic flux is
Adjust within the allowable range by changing the magnetic path cross-sectional area formed by the inner peripheral surface of the yoke and the outer peripheral surface of the small diameter rear housing and the magnetic path cross-sectional area formed by the outer peripheral surface of the yoke and the inner peripheral surface of the large rear housing. Therefore, the distance between the inner peripheral surface of the yoke and the outer peripheral surface of the small-diameter rear housing (magnetic path length)
Alternatively, prepare a plurality of yokes with different distances (magnetic path length) between the outer peripheral surface of the yoke and the inner peripheral surface of the large-diameter rear housing,
The variation of the transmission torque is adjusted within an allowable range by properly using the plurality of prepared yokes.

[0003]

In the above conventional clutch device, in order to adjust the variation of the transmission torque within the allowable range, the distance between the inner peripheral surface of the yoke and the outer peripheral surface of the small-diameter rear housing portion (magnetic path length). Alternatively, it is necessary to prepare a plurality of yokes having different distances (magnetic path lengths) between the outer peripheral surface of the yoke and the inner peripheral surface of the large-diameter rear housing portion, which increases the cost and requires replacement of the yoke for manufacturing. There was a problem that took time.

[0004]

In order to solve the above-mentioned problems, the structural features of the invention as set forth in claim 1 are as follows: a rotating shaft rotatably supported by a case on a rotation axis; A housing that is integrally connected to the rotation shaft and has a clutch storage chamber formed therein, a rotating member that is rotatably supported by the housing and extends into the clutch storage chamber, and the clutch storage chamber. A main outer clutch plate whose relative rotation is restricted by the peripheral surface and which is engaged movably in the axial direction, and an alternate arrangement with the main outer clutch plate, which is restricted in rotation by the rotating member and is movable in the axial direction. A main clutch having a combined main inner clutch plate, and a clutch engaged with the peripheral surface of the clutch housing chamber so as to be movable relative to the axial direction. A pilot clutch provided with a lot outer clutch plate and a pilot inner clutch plate which are alternately arranged with the pilot outer clutch plate and whose relative rotation is restricted by the first cam member and which is movably engaged in the axial direction, and the housing. The large-diameter rear housing portion fixed to the opening of the and the small-diameter rear housing portion that rotatably supports the rotating member are integrated by a non-magnetic annular intermediate member at a position facing the armature with the pilot clutch interposed therebetween. A rear housing that is coupled to the main housing, a yoke that is disposed between the large diameter and small diameter rear housing portions, and has a fixed electromagnet that attracts the armature and press-contacts the pilot outer clutch plate and the pilot inner clutch plate; Second cam part that contacts the clutch A cam that moves the second cam member in the axial direction by the operation of the cam mechanism by the relative rotation between the first cam member and the first cam member to amplify the transmission torque of the pilot clutch based on the attraction of the electromagnet to press the main clutch. In an electromagnetic pilot clutch device having a rotary amplifying mechanism, the yoke is fixed to a rear case that rotatably supports the rotating member, and the small-diameter rear housing portion and the inner peripheral surface of the yoke are provided between the yoke and the rear housing. And an outer magnetic path portion in which the large-diameter rear housing portion and the outer peripheral surface of the yoke face each other, and the inner magnetic path portion and the inner magnetic path portion are formed by relative movement of the yoke in the rotation axis direction. By changing one or both of the magnetic path cross-sectional areas of the outer magnetic path portion, the rotating shaft and the rotating member with respect to the current supplied to the electromagnet. The position adjusting device is provided to position the rear case in the direction of the rotation axis and fix the rear case to the case so that the variation in the transmission torque between the two cases falls within the allowable range.

According to a second aspect of the present invention, there is provided an electromagnetic pilot clutch device according to the first aspect, wherein the inner magnetic path portion is formed at an inner peripheral surface of the small-diameter rear housing portion. It is constituted by a land portion and a step portion formed on the inner peripheral surface of the yoke so as to face the inner land portion.

According to a third aspect of the present invention, there is provided the electromagnetic pilot clutch device according to the first aspect, wherein the outer magnetic path portion is formed on an outer diameter portion formed on the yoke and the outer diameter portion. The outer land portion is formed at the end of the inner peripheral surface of the large-diameter rear housing portion so as to face each other.

According to a fourth aspect of the present invention, in the electromagnetic pilot clutch device according to any one of the first to third aspects, the rear case is screwed into the case, and the rear case is rotated in the rotational axis direction. After adjusting the position, the rear case is fixed to the case by welding, caulking or double nuts.

According to a fifth aspect of the present invention, in the method of manufacturing the electromagnetic pilot clutch device according to the fourth aspect, the rotating shaft and the rotating shaft are rotated while a predetermined current is applied to the electromagnet. The transmission torque between the member and the member is measured, the position of the rear case is adjusted in the axial direction so that the error of the transmission torque is within an allowable value, and then the rear case is fixed to the case.

According to a sixth aspect of the present invention, in the method of manufacturing an electromagnetic pilot clutch device according to the fifth aspect, the rear case is biased in one direction of a rotation axis with respect to the case. In this state, the position of the rear case is adjusted in the axial direction.

[0010]

In the invention according to claim 1 configured as described above, the yoke is fixed to the rear case in which the rotating member is rotatably supported, and the small-diameter rear housing portion and the inner peripheral surface of the yoke are formed. At least one of the magnetic path cross-sectional area of the opposing inner magnetic path portion and the magnetic path cross-sectional area of the outer magnetic path portion where the large diameter rear housing portion and the outer peripheral surface of the yoke face each other is changed by movement of the yoke in the rotation axis direction, Since the rear case is positionally adjusted in the rotation axis direction so that the variation of the transmission torque between the rotating shaft and the rotating member with respect to the current supplied to the electromagnet falls within the allowable range, it is fixed to the case, so the variation of the transmission torque is adjusted. In order to achieve this, the distance between the inner peripheral surface of the yoke and the outer peripheral surface of the small diameter rear housing part (magnetic path length) or the distance between the outer peripheral surface of the yoke and the inner peripheral surface of the large diameter rear housing part (magnetic path length) was changed. There is no need for a plurality prepared over click,
The cost can be reduced, and the variation of the transmission torque can be easily and quickly adjusted without replacing the yoke.

In the invention according to claim 2 configured as described above, the inner magnetic path portion is disposed inside the yoke so as to face the inner land portion formed at the end portion of the outer peripheral surface of the small-diameter rear housing portion and the inner land portion. Since the step portion is formed on the peripheral surface, it is possible to adjust the variation of the transmission torque by changing the magnetic path area of the inner magnetic path portion by moving the yoke in the rotation axis direction.

In the invention according to claim 3 configured as described above, the outer magnetic path portion has an outer diameter portion formed on the yoke and an inner peripheral surface of the large-diameter rear housing portion facing the outer diameter portion. Since it is composed of the outer land portion formed at the end portion, it is possible to adjust the variation of the transmission torque by changing the magnetic path area of the outer magnetic path portion by moving the yoke in the rotation axis direction.

In the invention according to claim 4 configured as described above, the position of the rear case screwed to the case is adjusted in the direction of the rotation axis, and then the rear case is fixed to the case by welding, caulking or a double nut. Can be performed quickly and easily, and the adjusted position can be held securely.

In the invention according to claim 5 configured as described above, the transmission torque between the rotating shaft and the rotating member is measured with a predetermined current flowing in the electromagnet, and the error in the transmission torque is allowed. The rear case is fixed to the case after adjusting the position of the rear case in the axial direction so that it falls within the range.
Even if the yoke is not replaced, the position of the rear case can be adjusted to easily adjust the variation of the transmission torque.

In the invention according to claim 6 configured as described above, since the rear case is axially adjusted in the axial direction with the rear case being biased in one direction of the rotation axis direction, the screw portion, etc. It is possible to adjust the transmission torque while preventing the position of the yoke from changing due to the backlash.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electromagnetic pilot clutch device and a method of manufacturing the same according to the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of an electromagnetic pilot type clutch device 10, in which a case 11 is attached to a vehicle body such as a motorcycle. The case 11 includes a cylindrical case body 11 a and a rear case 20. Inside the case 11, the oil chamber 1 in which the clutch oil 19 is stored is stored.
Two are provided. The oil chamber 12 has a housing 1
3 is accommodated, and the front end face 22 of the housing 13 is
A flange portion formed on the connecting member 17 that connects the housing 13 and the rotary shaft 21 is fixed to the end surface 22 of the housing 13 by a plurality of bolts 30. Connecting member 17
The outer peripheral surface of the cylindrical portion is rotatably supported by the bearing 27, an inner spline is formed on the inner peripheral surface, and is spline-fitted with an outer spline formed on the outer peripheral surface at the tip of the rotating shaft 21. An annular oil seal 53 for preventing the clutch oil 19 from leaking to the outside is attached to the outer peripheral surface of the distal end of the cylindrical portion of the connecting member 17. In addition, the rotary shaft 21
A cylindrical protective case 6 for protecting the rotary shaft 21 is provided on the outer periphery of the
1 is attached to the case body 11 a with a predetermined distance from the rotary shaft 21 and is fixed by a plurality of bolts 60.

Inside the housing 13, a stepped cylindrical inner shaft 15 as a rotating member extends along the axis of rotation. The inner shaft 15 includes a housing 13
Is rotatably supported by bearings 24, 28 and a needle bearing 25. An inner spline is formed on the inner peripheral surface of the rear end portion of the inner shaft 15, and is spline-fitted with an outer spline formed at the front end portion of the output shaft 23.
On the outer periphery of the rear portion of the inner shaft 15, the clutch oil 1
An annular oil seal 54 is attached to prevent 9 from leaking from the oil chamber 12 to the outside.

A clutch storage chamber 14 is provided in the housing 13.
Is formed, and the main clutch 16 is provided. The main clutch 16 is a wet multi-plate friction clutch and includes a plurality of main inner clutch plates 31 and a main outer clutch plate 32. The main inner clutch plate 31 has the inner shaft 15
The main outer clutch plate 32 is spline-fitted to the outer periphery of the housing so as to be movable in the axial direction, and the main outer clutch plate 32 is spline-fitted to the spline teeth formed on the inner peripheral surface of the clutch housing chamber 14 of the housing 13 to move in the axial direction. It is assembled as possible. The main inner clutch plates 31 and the main outer clutch plates 32 are arranged alternately, and when they are engaged, they abut each other and frictionally engage, and when they are disengaged, they are separated from each other and are in a disengaged state. Housing 1
The peripheral wall of 3 is provided with a plurality of connecting holes 46 and 47 that are opened so that the clutch oil 19 can circulate in the oil chamber 12 and the clutch storage chamber 14.

The cam type amplification mechanism 18 includes the main clutch 1
The first cam member 44, the second cam member 45, and a plurality of cam followers 40 are arranged behind the reference numeral 6. One of the second cam members 45 is in contact with the main clutch 16 while being spline-fitted to the outer periphery of the inner shaft 15, and the cam mechanism presses the main clutch 16. The first cam member 44 is fitted to the outer circumference of the inner shaft 15 behind the second cam member 45 with the plurality of cam followers 40 interposed therebetween, and is located on the inner circumference side of the pilot clutch 34 described later. The plurality of cam followers 40 are interposed in the cam grooves formed between the first and second cam members 44 and 45. Between the second cam member 45 and the shoulder portion 58 of the inner shaft 15,
A spring 55 is interposed, and the repulsive force of the spring 55 urges the second cam member 45 in the direction in which it disengages from the main clutch 16. When the cam mechanism is inoperative, the main inner clutch plate 31 and the main outer clutch Clutch plate 3
2 are separated from each other and the second cam member 44 is pressed to move the plurality of cam followers 40 to the first and second cam members 44, 4
It is stored in the cam groove between 5.

The pilot clutch 34 is composed of a pilot outer clutch plate 42 and a pilot inner clutch plate 43, and is arranged behind the second cam member 44. The pilot outer clutch plate 42 is formed on the inner peripheral surface of the clutch housing chamber 14. And the pilot inner clutch plate 43 is attached to the first cam member 44 by spline fitting so as to be movable in the axial direction.
The outer peripheral surface of the is fitted by a spline so as to be movable in the axial direction. The armature 35 has an annular shape, is arranged between the pilot clutch 34 and the second cam member 45, and is spline-fitted to the inner peripheral surface of the clutch housing chamber 14 so as to be movable in the axial direction. Armature 35
Is attracted by a magnetic flux formed from an electromagnet 33, which will be described later, as a base point, and presses the pilot clutch 34.

A rear housing 57 that covers the opening of the housing 13 is fitted behind the pilot clutch 34. The rear housing 57 includes a small diameter rear housing portion 37, a large diameter rear housing portion 38, and an intermediate member 39. The small-diameter rear housing portion 37 has a stepped tubular shape, and rotatably supports the inner shaft 15 via a needle bearing 25. A stepped cylindrical large-diameter rear housing portion 38 is arranged on the outer periphery of the small-diameter rear housing portion 37 at a predetermined interval and is screwed into a female screw engraved on the inner peripheral surface of the opening of the housing 13. . An annular intermediate member 39 made of stainless steel is interposed between the inner peripheral surface of the large-diameter rear housing portion 38 and the outer peripheral surface of the small-diameter rear housing portion 37, and welded to the small-diameter and large-diameter rear housing portions 37, 38. Are integrally fixed by. After the rear housing 57 is screwed into the housing 13 to adjust its position, the outer periphery of the large-diameter rear housing portion 38 is fixed by the double nut 56. The small-diameter and large-diameter rear housing portions 37, 38 are made of a magnetic material, and the intermediate member 39 is made of a non-magnetic material, so that a magnetic flux is easily formed by the electromagnet 33 described later.

The electromagnet 33 has an annular shape, and the intermediate member 3
9, it is interposed in a position surrounded by the small-diameter and large-diameter rear housing portions 37, 38, is energized by an energizing cord 59, and is fixed to an annular yoke 36. York 36
Forms an inner magnetic path portion 63 and an outer magnetic path portion 64 between the small-diameter and large-diameter rear housing portions 37, 38 with a small gap between the small-diameter and large-diameter rear housing portions 37, 38. The inner magnetic path portion 63 includes an inner land portion 51 formed at an end portion of an outer peripheral surface of the small-diameter rear housing portion 37 and the inner land portion 51.
Is a minute gap through which a magnetic flux is formed between the step portion 52 formed on the inner peripheral surface of the yoke 36 so as to be opposed to the inner land portion 51 and the step portion 52 where the magnetic flux can pass. Is the magnetic path cross-sectional area 65. The outer magnetic path portion 64 is
The magnetic flux formed between the outer diameter portion 48 formed on the yoke 36 and the outer land portion 49 formed at the end portion of the inner peripheral surface of the large diameter rear housing portion 38 facing the outer diameter portion 48 passes therethrough. The area where the outer diameter portion 48 and the outer land portion 49, which are minute gaps, through which the magnetic flux can pass, is the magnetic path cross-sectional area 66.
Is.

The yoke 36 is fixed to the rear case 20 by a plurality of bolts 62, and the rear case 20 rotatably supports the inner shaft 15 via a bearing 28. A male screw portion 29 formed on the outer circumference of the rear case 20 is screwed with a female screw portion 26 formed on the inner circumference of the case body 11a, and a liquid-tight state is maintained by an annular oil seal 41. After the housing 13 and the components are assembled to the case body 11a, the rear case 20 is attached to the case body 11a by welding 50, caulking or double nuts.
Fixed to.

In the manufacture of the electromagnetic pilot clutch device 10 having the above-described structure, in order to adjust the transmission torque, the clutch device 10 is assembled and the rear case 20 is not fixed. An unillustrated measuring device for measuring the torque transmitted to and from the shaft 15 is attached to the clutch device 10. Next, energizing cord 5
The transmission torque between the rotary shaft 21 and the inner shaft 15 is measured by a measuring instrument in a state where a predetermined current is applied to the electromagnet 33 from the motor 9. By rotating the rear case 20, the inner magnetic path portion 6
3 and the magnetic path cross-sectional areas 65 and 66 of the outer magnetic path portion 64 are changed to adjust the positions so that the error of the transmission torque falls within the allowable range. When rotating the rear case 20,
The yoke 36 is rotated while being biased in one direction so that the position of the yoke 36 does not change due to backlash such as a screw. After the position adjustment is completed, the rear case 20 is fixed to the case body 11a by welding 50, caulking, a double nut or the like.

Next, the operation of the electromagnetic pilot type clutch device 10 configured as described above will be described. As shown in FIG. 2, the electromagnetic pilot clutch device 10 is mounted on a path for transmitting a driving force to the rear wheels 5 of a motorcycle or an automobile and functions as a starting clutch device.
When the engine 6 is started, the output of the engine 6 is input to the V-belt type automatic transmission (CVT) 8, is decelerated by the first speed reducer 7, and is then transmitted to the input shaft 21 to drive the housing 13 to rotate. To be done. When starting the engine 6, normally
Since the electromagnet 33 is in the non-energized state, no magnetic flux is formed,
The pilot clutch 34 is in the disengaged state. At this time, the second cam member 45 is biased by the spring 55 and disengages from the main clutch 16, and the main inner clutch plate 31 and the main outer clutch plate 32 are separated from each other, and the main inner clutch plate 31 and the main inner clutch plate 31 are separated from each other. The outer clutch plate 32 rotates relative to each other, and torque is not transmitted from the rotary shaft 21 to the output shaft 23. Second
The cam member 45 has the cam follower 4 by the repulsive force of the spring 55.
It is pressed against the first cam member 44 via 0, and the pilot clutch 34 is not rotating because it is in the disengaged state.

When the energizing cord 59 energizes the electromagnet 33, a magnetic flux is formed with the electromagnet 33 as a base point. The magnetic flux is transferred from the electromagnet 33 to the yoke 36 to the yoke 3
6 through the inner magnetic path portion 63 to the inner land portion 51 of the small diameter rear housing portion 37, from the small diameter rear housing portion 37 to the pilot clutch 34 to the armature 35, and from the armature 35 to the large diameter rear housing portion. Three
8, from the outer land portion 49 of the large-diameter rear housing portion 38 through the outer magnetic path portion 64 to the outer diameter portion 48 of the yoke 36,
A magnetic flux that circulates from the yoke 36 to the electromagnet 33 is formed to attract the armature 35. Due to the suction, the armature 35 presses the pilot clutch 34 and frictionally engages it, so that relative rotation occurs between the first cam member 44 and the second cam member 45 of the cam type amplification mechanism 18, and the cam follower 40 and the cam follower 40. Due to the action of the groove, the second cam member 45 moves in a direction in which the main inner clutch plate 31 and the main outer clutch plate 32 of the main clutch 16 are brought into pressure contact with each other, and the pilot clutch 34 is attached to the main clutch 16.
A transmission torque corresponding to the frictional engagement force of is generated. The transmission torque is transmitted to the output shaft 23 via the inner shaft 15, is decelerated by the second reduction gear 9 and is transmitted to the axle 4, and the rear wheel 5 such as a motorcycle is rotationally driven.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an electromagnetic pilot clutch device according to the present invention.

FIG. 2 is a diagram showing a driving force transmission path of a motorcycle or the like using the electromagnetic pilot clutch device according to the present invention.

[Explanation of symbols]

10 ... Clutch device, 11 ... Case, 11a
..Case body, 12 ... Oil chamber, 13 ... Housing, 14 ... Clutch storage chamber, 15 ... Inner shaft (rotating member), 16 ... Main clutch, 1
8 ... Cam type amplification mechanism, 20 ... Rear case, 21
... Rotary shaft, 23 ... Output shaft, 26 ... Female screw part, 29 ... Male screw part, 33 ... Electromagnet, 34 ...
・ Pilot clutch, 35 ... Armature, 36 ・
..Yoke, 37 ... Small-diameter rear housing part, 38 ..
..Large-diameter rear housing part, 39 ... Intermediate member, 40
... Cam followers, 44 ... First cam members, 45 ...
..Second cam member, 48 ... outer diameter portion, 49 ... outer land portion, 50 ... welding, 51 ... inner land portion,
52 ... Step portion, 55 ... Spring, 56 ... Double nut, 57 ... Rear housing, 59 ... Energizing cord, 63 ... Inner magnetic path portion, 64 ... Outer magnetic path Part, 6
5, 66 ... Magnetic path cross-sectional area.

Claims (6)

[Claims] 1. A rotary shaft rotatably supported on a rotation axis of a case, a housing disposed in the case, integrally connected to the rotary shaft, and having a clutch storage chamber formed therein, A rotating member that is rotatably supported by a housing and extends into the clutch housing chamber, a main outer clutch plate that is engaged with an outer circumferential surface of the clutch housing chamber and is movably in an axial direction, and the main outer clutch plate. A main clutch having a main inner clutch plate that is alternately arranged with an outer clutch plate and that is restricted in rotation by the rotating member and is engaged so as to be movable in the axial direction, and relative rotation is restricted in the clutch storage chamber inner peripheral surface. And outer pilot clutch plates engaged with each other so as to be movable in the axial direction and arranged alternately with the outer pilot clutch plates And a pilot inner clutch plate that is engaged with the first cam member so that relative rotation is restricted and is movable in the axial direction,
A large-diameter rear housing portion fixed to the opening of the housing and a small-diameter rear housing portion that rotatably supports the rotating member are located between the armature and the armature with the pilot clutch interposed therebetween. A rear housing integrally joined by means of a yoke, and an electromagnet fixed between the large-diameter and small-diameter rear housing portions, and a yoke to which an electromagnet is fixed, which attracts the armature and press-contacts the pilot outer clutch plate and the pilot inner clutch plate, The second cam member is moved in the axial direction by the operation of the cam mechanism due to the relative rotation of the second cam member and the first cam member that are in contact with the main clutch, and the main clutch is based on the attraction of the electromagnet. Has a cam type amplification mechanism that amplifies the transmission torque of In a magnetic pilot type clutch device, the yoke is fixed to a rear case that rotatably supports the rotating member, and an inner magnetic body in which the small-diameter rear housing portion and the inner peripheral surface of the yoke face each other between the yoke and the rear housing. One of the inner magnetic path portion and the outer magnetic path portion constitutes an outer magnetic path portion in which the path portion and the large-diameter rear housing portion and the outer peripheral surface of the yoke are opposed to each other, and relative movement of the yoke in the rotation axis direction is performed. Or, by changing the magnetic path cross-sectional areas of both, the position of the rear case is adjusted in the rotation axis direction so that the variation of the transmission torque between the rotating shaft and the rotating member with respect to the current supplied to the electromagnet falls within an allowable range. And an electromagnetic pilot clutch device characterized in that a position adjusting device for fixing to the case is provided. 2. The electromagnetic pilot clutch device according to claim 1, wherein the inner magnetic path portion faces an inner land portion formed at an outer peripheral end of the small diameter rear housing portion and the inner land portion. An electromagnetic pilot clutch device comprising a step portion formed on the inner peripheral surface of the yoke. 3. The electromagnetic pilot clutch device according to claim 1, wherein the outer magnetic path portion is an outer diameter portion formed in the yoke, and an inner diameter of the large diameter rear housing portion is opposed to the outer diameter portion. An electromagnetic pilot-type clutch device comprising an outer land portion formed at an end portion of a peripheral surface. 4. The electromagnetic pilot clutch device according to any one of claims 1 to 3, wherein the rear case is screwed into the case, and the rear case is positionally adjusted in the rotation axis direction, and then the rear case is welded, crimped, or An electromagnetic pilot clutch device, which is fixed to the case with a double nut. 5. The method for manufacturing an electromagnetic pilot clutch device according to claim 4, wherein a transfer torque between the rotary shaft and the rotary member is measured in a state where a predetermined current is applied to the electromagnet, A method for manufacturing an electromagnetic pilot clutch device, comprising: adjusting the position of the rear case in the axial direction so that the error of the transmission torque is within an allowable value, and then fixing the rear case to the case. 6. The method of manufacturing an electromagnetic pilot clutch device according to claim 5, wherein the rear case is axially adjusted in a state in which the rear case is biased with respect to the case in one direction of a rotation axis direction. A method for manufacturing an electromagnetic pilot type clutch device characterized by the above.