JP7336907B2 - clutch unit - Google Patents

Description

The present invention is a clutch unit provided with an input-side clutch portion to which rotational torque is input, and an output-side clutch portion that transmits rotational torque from the input-side clutch portion to the output side and cuts off the rotational torque from the output side. Regarding.

In a clutch unit using engaging elements such as cylindrical rollers, a clutch portion is provided between an input member and an output member. The clutch unit is configured to control transmission and interruption of rotational torque by engaging and disengaging an engaging element between the input member and the output member.

The applicant of the present invention has previously proposed a clutch unit incorporated in a seat lifter portion for automobiles that vertically adjusts a seat by operating a lever (see, for example, Patent Document 1).

The clutch unit disclosed in Patent Document 1 includes a lever-side clutch portion to which rotational torque is input by lever operation, and the rotational torque from the lever-side clutch portion is transmitted to the output side, and the rotational torque from the output side is cut off. and a brake-side clutch portion.

The main parts of the lever side clutch portion are the outer ring to which rotational torque is input by lever operation, the inner ring that transmits the rotational torque from the outer ring to the brake side clutch portion, and the engagement and disengagement of the wedge clearance between the outer ring and the inner ring. It consists of cylindrical rollers that control transmission and interruption of rotational torque from the outer ring.

The main parts of the brake-side clutch portion are an inner ring to which rotational torque is input from the lever-side clutch portion, an output shaft to which the rotational torque is output from the inner ring, a side plate, an outer ring, and a cover whose rotation is constrained, and an output shaft. Cylindrical rollers that control blocking of rotational torque from the output shaft and transmission of rotational torque from the inner ring by engagement and disengagement of the wedge clearance between the shaft and the outer ring, and friction rings that provide rotational resistance to the output shaft. It is configured.

In the lever-side clutch portion, when rotational torque is input to the outer ring by operating the lever, the cylindrical rollers are engaged with the wedge clearance between the outer ring and the inner ring. Due to the engagement of the cylindrical rollers with this wedge clearance, rotational torque is transmitted to the inner ring and the inner ring rotates.

In the brake-side clutch portion, when a rotational torque is reversely input to the output shaft due to seating on the seat, the cylindrical rollers engage with the wedge clearance between the output shaft and the outer ring, locking the output shaft with respect to the outer ring. . In this locked state, the rotational torque reversely input from the output shaft is interrupted. Thereby, the seat surface height of the seat is maintained.

On the other hand, when rotational torque is input from the lever-side clutch portion to the brake-side clutch portion by operating the lever, the inner ring presses the cylindrical rollers, thereby releasing the cylindrical rollers from the wedge clearance between the output shaft and the outer ring.

By disengaging the cylindrical rollers up to the wedge clearance, the locked state of the output shaft is released and the output shaft becomes rotatable. When the lock is released by operating the lever, the friction ring applies rotational resistance to the output shaft.

Then, when the inner ring rotates further, the rotational torque from the inner ring is transmitted to the output shaft, and the output shaft rotates. The seat height of the seat can be adjusted by rotating the output shaft.

JP 2011-169402 A

By the way, the brake-side clutch portion has a structure in which an output shaft, cylindrical rollers and an inner ring, which are sliding members, are housed in an internal space surrounded by a side plate, an outer ring and a cover, which constitute stationary members (see Patent Document 1). See Figure 1).

In this brake-side clutch portion, the sliding member rotates and slides with respect to the stationary member which is in a fixed state. For this reason, in order to allow the sliding members to rotate and slide smoothly, it is necessary to provide a certain axial clearance between the stationary member and the sliding member or between the sliding members.

If there is such an axial clearance, the axial play of the sliding member occurs in the internal space of the stationary member. That is, there is a possibility that the axial dimension at which the friction ring is press-fitted onto the output shaft and the axial position at which the cylindrical roller contacts the output shaft may vary.

If the press-fit dimension of the friction ring fluctuates, the rotational resistance (operation torque) imparted to the output shaft by the friction ring during lever operation will vary. Further, when the contact position of the cylindrical roller fluctuates, the braking force when locking the output shaft varies.

SUMMARY OF THE INVENTION Accordingly, the present invention has been proposed in view of the above-mentioned problems, and its object is to provide a clutch unit that can suppress the axial play of the sliding member in the internal space of the stationary member by a simple means. to do.

A clutch unit according to the present invention includes an input-side clutch portion that controls transmission and interruption of input rotational torque, and a rotational torque that is transmitted from the input-side clutch portion to an output side and reversely input from the output side. and an output-side clutch portion that cuts off the

The output-side clutch portion of the present invention includes a stationary member whose rotation is constrained, and a plurality of sliding members housed in the interior space of the stationary member.

As a technical means for achieving the above object, the present invention provides an axial gap formed between a stationary member and a sliding member or between sliding members to provide an axial gap between the sliding member and the stationary member. It is characterized by interposing a spacer for suppressing directional looseness.

In the present invention, as the sliding member, the inner ring that rotates by the rotational torque input to the input side clutch portion and the inner ring that rotates by the rotational torque from the inner ring and the sliding member that rotates when the rotational torque is reversely input from the output side are provided. an output shaft locked to the stationary member, and axial clearances formed between the stationary member and the inner ring, between the inner ring and the output shaft, and between the output shaft and the stationary member. By interposing a spacer in one of the axial gaps, the two surfaces forming the axial gap are brought into contact with each other in all the other axial gaps. In other words, the spacer axially restricts the position of the sliding member in the interior space of the stationary member. By narrowing the axial clearance by restricting the axial position, it is possible to suppress the axial play of the sliding member in the internal space of the stationary member.

In the present invention, the stationary member is composed of the side plate and the cover, the sliding member is composed of the output shaft and the inner ring, and the spacers are provided between the side plate and the output shaft, between the cover and the inner ring, and between the output shaft and the inner ring. A structure that intervenes at any one point between is desirable.

By adopting such a structure, the axial play of the sliding member can be reduced by reducing the axial clearance existing between the side plate and the output shaft, between the cover and the inner ring, or between the output shaft and the inner ring. can be suppressed.

The spacer in the present invention is preferably either a plate-like member or an elastic member.

By adopting such a structure, it is possible to easily construct a spacer that suppresses the axial play of the sliding member.

The input-side clutch portion and the output-side clutch portion in the present invention preferably have a structure incorporated in the seat lifter portion for automobiles.

By adopting such a structure, it is possible to incorporate in a seat lifter portion for an automobile as a clutch unit in which the input-side clutch portion is the lever-side clutch portion and the output-side clutch portion is the brake-side clutch portion.

According to the present invention, the spacer axially regulates the position of the sliding member in the interior space of the stationary member. By narrowing the axial clearance by restricting the axial position, it is possible to suppress the axial looseness of the sliding member in the internal space of the stationary member.

In this way, since the axial play of the sliding member can be suppressed, when the clutch unit is incorporated in the seat lifter part for automobiles, the press-fit dimension of the friction ring to the output shaft and the contact position of the cylindrical roller with respect to the output shaft can be kept constant. Since it can be held, the rotation resistance of the output shaft and the braking force can be stabilized.

1 is a cross-sectional view showing the overall configuration of a clutch unit in an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view taken along line PP of FIG. 1; FIG. 2 is a cross-sectional view taken along line QQ of FIG. 1; 1 is a configuration diagram showing a seat and a seat lifter portion of an automobile; FIG. FIG. 4 is an enlarged cross-sectional view of a main portion illustrating a case in which a plate-like member is interposed as a spacer between the output shaft and the inner ring; FIG. 4 is an enlarged cross-sectional view of a main part illustrating a case where a plate-like member is interposed as a spacer between a cover and an inner ring; FIG. 5 is an enlarged cross-sectional view of a main part illustrating a case where a plate-like member is interposed between the side plate and the output shaft as a spacer; FIG. 4 is an enlarged cross-sectional view of a main part illustrating a case where an elastic member is interposed as a spacer between the output shaft and the inner ring; FIG. 4 is an enlarged cross-sectional view of a main part illustrating a case where an elastic member is interposed as a spacer between a cover and an inner ring; FIG. 4 is an enlarged cross-sectional view of a main part illustrating a case where an elastic member is interposed as a spacer between a side plate and an output shaft;

An embodiment of a clutch unit according to the present invention will be described in detail based on the drawings. In the following embodiments, a clutch unit incorporated in an automobile seat lifter portion is exemplified, but it is applicable to other than the automobile seat lifter portion.

1 is a cross-sectional view showing the overall structure of the clutch unit, FIG. 2 is a cross-sectional view taken along line PP of FIG. 1, and FIG. 3 is a cross-sectional view taken along line QQ of FIG. Before describing the characteristic configuration of this embodiment, the overall configuration of the clutch unit will be described.

As shown in FIG. 1, the clutch unit 10 of this embodiment has a structure in which a lever side clutch portion 11 as an input side clutch portion and a brake side clutch portion 12 as an output side clutch portion are unitized.

The lever-side clutch portion 11 controls transmission and interruption of rotational torque input by lever operation. The brake-side clutch portion 12 transmits the rotational torque from the lever-side clutch portion 11 to the output side, and cuts off the rotational torque reversely input from the output side.

1 and 2, the main parts of the lever-side clutch portion 11 include a side plate 13, an outer ring 14, an inner ring 15, a plurality of cylindrical rollers 16, a retainer 17, an inner centering spring 18, and an outer centering spring 19 .

A claw portion 13a extending in the axial direction is formed on the outer periphery of the side plate 13, and a notch recess 14a is formed on the outer periphery of the outer ring 14. As shown in FIG. The side plate 13 and the outer ring 14 are integrated by fitting the pawl portion 13a into the notch recess portion 14a and crimping them. Input of rotational torque to the outer ring 14 is performed by an operation lever 43 (see FIG. 4) attached to the side plate 13 .

The inner ring 15 includes a tubular portion 15a through which the output shaft 22 is inserted, an enlarged diameter portion 15b extending radially outward from the brake-side end of the tubular portion 15a, and an outer circumference of the enlarged diameter portion 15b extending in the axial direction. and a plurality of pillars 15c (see FIG. 3). The inner ring 15 transmits rotational torque input from the outer ring 14 to the brake-side clutch portion 12 .

A plurality of cam surfaces 14b are formed on the inner circumference of the outer ring 14 at equal intervals in the circumferential direction. A wedge clearance 20 is formed between the cam surface 14 b of the outer ring 14 and the cylindrical surface 15 d of the tubular portion 15 a of the inner ring 15 .

Cylindrical rollers 16 are arranged between outer ring 14 and inner ring 15 . Cylindrical rollers 16 control transmission and interruption of rotational torque from outer ring 14 by engagement and disengagement at wedge clearances 20 formed between cam surface 14b of outer ring 14 and cylindrical surface 15d of inner ring 15 .

The retainer 17 has a plurality of pockets 17a for accommodating the cylindrical rollers 16 formed at equal intervals in the circumferential direction. The retainer 17 retains the cylindrical rollers 16 with a wedge clearance 20 between the cam surface 14b of the outer ring 14 and the cylindrical surface 15d of the inner ring 15 by means of pockets 17a.

The inner centering spring 18 is a C-shaped elastic member with a circular cross section disposed between the retainer 17 and the cover 24 of the brake-side clutch portion 12, and both ends thereof are attached to the retainer 17 and a part of the cover 24. I have it locked.

When a rotational torque is input from the outer ring 14 by lever operation, the inner centering spring 18 expands its diameter with respect to the stationary cover 24 as the retainer 17 following the outer ring 14 rotates, and elastic force is accumulated. be. When the rotational torque input from the outer ring 14 ceases, the elastic force of the inner centering spring 18 causes the retainer 17 to return to its neutral state.

The outer centering spring 19 positioned radially outwardly of the inner centering spring 18 is a C-shaped strip elastic member disposed between the outer ring 14 and the cover 24 of the brake-side clutch portion 12, and both ends thereof are The outer ring 14 and a part of the cover 24 are locked.

When a rotational torque is input from the outer ring 14 by lever operation, the outer centering spring 19 expands in diameter as the outer ring 14 rotates with respect to the stationary cover 24 and accumulates elastic force. When the rotational torque is no longer input from the outer ring 14, the elastic force of the outer centering spring 19 causes the outer ring 14 to return to its neutral state.

As shown in FIGS. 1 and 3, the main parts of the brake-side clutch portion 12 are a column portion 15c of the inner ring 15 extending from the lever-side clutch portion 11, an output shaft 22, an outer ring 23 as a stationary system, a cover 24, and an outer ring 23. It is composed of a side plate 25 , a plurality of pairs of cylindrical rollers 27 , a leaf spring 28 having an N-shaped cross section, and a friction ring 29 .

The output shaft 22 includes a shaft portion 22a to which the cylindrical portion 15a of the inner ring 15 is fitted, a large-diameter portion 22b extending radially outward from a substantially central portion of the shaft portion 22a, and an output side of the shaft portion 22a. and a pinion gear portion 22d formed in the . Rotational torque from the lever-side clutch portion 11 is output to the output shaft 22 .

A plurality of (six in FIG. 3) flat cam surfaces 22e are formed at equal intervals in the circumferential direction on the outer periphery of the large diameter portion 22b. A wedge clearance 26 is formed between the cam surface 22 e of the large diameter portion 22 b and the cylindrical surface 23 a of the outer ring 23 . Two cylindrical rollers 27 and one leaf spring 28 interposed therebetween are arranged in the wedge clearance 26 .

The cylindrical rollers 27 are engaged and disengaged at the wedge clearance 26 to control blocking of rotational torque input from the output shaft 22 and transmission of rotational torque input from the column portion 15 c of the inner ring 15 . The leaf spring 28 applies a separating force to the cylindrical rollers 27 in the circumferential direction.

A plurality of pairs (six pairs in FIG. 3) of cylindrical rollers 27 and plate springs 28 are arranged at equal intervals in the circumferential direction by the column portions 15c of the inner ring 15. As shown in FIG. The column portion 15c has a function of transmitting rotational torque input from the outer ring 14 to the output shaft 22, and a function of accommodating the cylindrical rollers 27 and the plate springs 28 in the pockets 15f and holding them at regular intervals in the circumferential direction.

The large diameter portion 22b of the output shaft 22 is provided with a projection 22f for transmitting the rotational torque from the inner ring 15 to the output shaft 22. As shown in FIG. The protrusion 22f is inserted into a hole 15e formed in the enlarged diameter portion 15b of the inner ring 15 with a clearance in the circumferential direction.

The pinion gear portion 22d of the output shaft 22 is connected to the seat lifter portion 39 (see FIG. 4). By press-fitting a washer 31 through a wave washer 30 to the input side of the shaft portion 22a, the components of the lever-side clutch portion 11 are retained.

Notch recesses 23b and 24a are formed on the outer circumferences of the outer ring 23 and the cover 24, and a claw portion 25a extending in the axial direction is formed on the outer circumference of the side plate 25. As shown in FIG. The outer ring 23, the cover 24 and the side plate 25 are integrated by fitting the claw portions 25a into the cutout recesses 23b and 24a and crimping them.

The friction ring 29 is a resin member, for example, and is fixed to the side plate 25 . The friction ring 29 is press-fitted into the inner peripheral surface 22g of the annular recess 22c formed in the large-diameter portion 22b of the output shaft 22 with a fitting allowance.

Due to the frictional force generated between the outer peripheral surface 29a of the friction ring 29 and the inner peripheral surface 22g of the annular recess 22c, the output shaft 22 slides against the friction ring 29 fixed to the stationary side plate 25 when the lever is operated. is given rotational resistance.

An operation example of the lever-side clutch portion 11 and the brake-side clutch portion 12 having the structures as described above will be described below.

In the lever-side clutch portion 11 , when rotational torque is input to the outer ring 14 by operating the lever, the cylindrical rollers 16 are engaged with the wedge clearances 20 between the outer ring 14 and the inner ring 15 .

Due to the engagement of the cylindrical rollers 16 in the wedge clearances 20, rotational torque is transmitted to the inner ring 15, causing the inner ring 15 to rotate. At this time, elastic force is accumulated in both centering springs 18 and 19 as the outer ring 14 and retainer 17 rotate.

When the rotational torque input by the lever operation is stopped, the elastic force of both the centering springs 18 and 19 causes the retainer 17 and the outer ring 14 to return to the neutral state. The inner ring 15 maintains the given rotational position. As the outer ring 14 is repeatedly rotated by the pumping operation of the operating lever 43 (see FIG. 4), the inner ring 15 is inching rotated.

In the brake-side clutch portion 12, even if a rotational torque is reversely input to the output shaft 22 by sitting on the seat 40 (see FIG. 4), the cylindrical rollers 27 are engaged with the wedge clearances 26 between the output shaft 22 and the outer ring 23. As a result, the output shaft 22 is locked with respect to the outer ring 23 .

In this manner, the rotational torque reversely input from the output shaft 22 is locked by the brake-side clutch portion 12, and the return of the rotational torque reversely input to the lever-side clutch portion 11 is cut off. Thereby, the seat surface height of the seat 40 is maintained.

On the other hand, when the rotational torque from the lever-side clutch portion 11 is input to the inner ring 15 by operating the lever, the column portion 15c of the inner ring 15 comes into contact with the cylindrical rollers 27 and resists the elastic force of the plate springs 28, causing the cylindrical rollers 27 to rotate. press . As a result, the cylindrical rollers 27 are separated from the wedge clearances 26 .

By disengaging the cylindrical rollers 27 from the wedge clearance 26, the locked state of the output shaft 22 is released and the output shaft 22 becomes rotatable. When the lock is released by this lever operation, the friction ring 29 applies rotational resistance to the output shaft 22 .

Then, when the inner ring 15 rotates further, the clearance between the hole 15e of the enlarged diameter portion 15b of the inner ring 15 and the projection 22f of the large diameter portion 22b of the output shaft 22 closes, and the enlarged diameter portion 15b of the inner ring 15 becomes the projection of the output shaft 22. 22f in the rotational direction.

As a result, the rotational torque from the lever-side clutch portion 11 is transmitted to the output shaft 22 via the projection 22f, causing the output shaft 22 to rotate. That is, when the inner ring 15 inching rotates, the output shaft 22 also inching rotates. As a result, the seat surface height of the seat 40 can be adjusted.

The clutch unit 10 described above is incorporated in an automobile seat lifter portion 39 that adjusts the seat surface height of the seat 40 by operating a lever. FIG. 4 shows a seat 40 installed in the passenger compartment of an automobile.

As shown in FIG. 4, the height of the seating surface of the seat 40 in the seat lifter portion 39 is adjusted by an operation lever 43 attached to the side plate 13 (see FIG. 1) of the lever-side clutch portion 11. As shown in FIG. The seat lifter portion 39 has the following structure.

One ends of link members 45 and 46 are rotatably pivoted to the slide movable member 44 . The other ends of the link members 45 and 46 are rotatably pivoted to the seat 40 . A sector gear 47 is integrally provided at the other end of the link member 45 . The sector gear 47 meshes with the pinion gear portion 22 d of the output shaft 22 .

For example, when the seat surface of the seat 40 is lowered, the lever side clutch portion 11 is operated, that is, the operation lever 43 of the seat lifter portion 39 is swung downward, whereby the brake side clutch portion 12 (FIG. 1) is lowered. See) is unlocked.

When the brake-side clutch portion 12 is unlocked, the seat surface of the seat 40 can be smoothly lowered by applying appropriate rotational resistance to the output shaft 22 with the friction ring 29 (see FIG. 1).

When the brake-side clutch portion 12 is unlocked, the rotational torque transmitted from the lever-side clutch portion 11 to the brake-side clutch portion 12 causes the pinion gear portion 22d of the output shaft 22 to rotate clockwise (in the direction of the arrow in FIG. 4). move.

Then, the sector gear 47 that meshes with the pinion gear portion 22d swings counterclockwise (in the direction of the arrow in FIG. 4), and both the link members 45 and 46 tilt to lower the seating surface of the seat 40. As shown in FIG.

After adjusting the seat surface height of the seat 40 in this manner, when the operating lever 43 is released, the operating lever 43 swings upward due to the elastic force of both the centering springs 18 and 19, returning to its original position (neutral position). state).

Note that when the operation lever 43 is swung upward, the seat surface of the seat 40 is raised by an operation opposite to that described above. When the operating lever 43 is released after adjusting the seat surface height of the seat 40, the operating lever 43 swings downward and returns to its original position (neutral state).

The overall configuration of the clutch unit 10 in this embodiment is as described above, but the stationary member and sliding member of the brake-side clutch portion 12, which are its characteristic configuration, will be described in detail below.

The brake-side clutch portion 12 has an output shaft 22 (large-diameter portion 22b), cylindrical rollers 27, and an inner ring 15 ( It has a structure that accommodates the enlarged diameter portion 15b) (see FIG. 1).

In the brake-side clutch portion 12, the output shaft 22 and the inner ring 15 rotate and slide with respect to the side plate 25 and the cover 24 which are in a stationary state. For this reason, in order to rotate and slide the output shaft 22 and the inner ring 15 smoothly, constant pressure is required between the side plate 25 and the output shaft 22, between the cover 24 and the inner ring 15, and between the output shaft 22 and the inner ring 15. Axial clearance is provided.

If such an axial clearance exists, axial play occurs between the output shaft 22 and the inner ring 15. In order to suppress this axial play, the output shaft 22 and the inner ring are arranged as shown in FIGS. 15, between the cover 24 and the inner ring 15, or between the side plate 25 and the output shaft 22.

In the embodiments shown in FIGS. 5 to 7, spacers 32, which are plate-shaped members such as shims, are exemplified. Moreover, in the embodiments shown in FIGS. 8 to 10, spacers 33, which are elastic members such as wave washers, are exemplified.

5 and 8 illustrate the case where spacers 32 and 33 are interposed between the output shaft 22 and the inner ring 15. FIG. 6 and 9 illustrate the case where spacers 32 and 33 are interposed between the inner ring 15 and the cover 24. FIG. 7 and 10 illustrate the case where spacers 32 and 33 are interposed between the output shaft 22 and the side plate 25. FIG.

In this way, by interposing the spacers 32 and 33 at any one point between the output shaft 22 and the inner ring 15, between the cover 24 and the inner ring 15, or between the side plate 25 and the output shaft 22, the output The positions of the shaft 22 and the inner ring 15 are restricted in the axial direction.

This axial position regulation closes the axial gap that exists between the side plate 25 and the cover 24 . In other words, one spacer 32, 33 can close all the axial gaps between the output shaft 22 and the inner ring 15, between the cover 24 and the inner ring 15, or between the side plate 25 and the output shaft 22. become.

The spacer 32, which is a plate-like member, closes the axial gap due to the thickness of the plate-like member. Moreover, the spacer 33, which is an elastic member, closes the gap in the axial direction due to the pressing force of the elastic member.

As described above, by narrowing the axial clearance, the axial looseness of the output shaft 22 and the inner ring 15 can be suppressed. As a result, the axial dimension at which the friction ring 29 is press-fitted onto the output shaft 22 and the axial position at which the cylindrical roller 27 contacts the cam surface 22e of the output shaft 22 can be kept constant.

Since the press-fit dimension of the friction ring 29 onto the output shaft 22 can be kept constant in this way, the rotational resistance (operation torque) imparted to the output shaft 22 by the friction ring 29 during lever operation is stabilized. Further, since the contact position of the cylindrical roller 27 with respect to the cam surface 22e of the output shaft 22 can be kept constant, the braking force when the output shaft 22 is locked is stabilized.

The present invention is by no means limited to the above-described embodiments, and can of course be embodied in various forms without departing from the gist of the present invention. It is defined by the claims, and includes all changes within the meaning of equivalents and the scope of the claims.

10 clutch unit 11 input side clutch portion (lever side clutch portion)
12 Output-side clutch (brake-side clutch)
15 sliding member (inner ring)
22 sliding member (output shaft)
24 stationary member (cover)
25 stationary member (side plate)
32 spacer (plate-like member)
33 spacer (elastic member)
39 seat lifter

Claims (4)

An input-side clutch portion that controls transmission and interruption of input rotational torque, and an output-side clutch portion that transmits rotational torque from the input-side clutch portion to the output side and interrupts rotational torque reversely input from the output side. Consists of
The output-side clutch portion is a clutch unit including a stationary member whose rotation is constrained and a plurality of sliding members accommodated in an internal space of the stationary member,
As the sliding member, an inner ring that rotates by the rotational torque input to the input side clutch portion, and a rotational torque from the inner ring that rotates and rotates against the stationary member when the rotational torque is reversely input from the output side. and an output shaft locked by
A spacer is interposed in any one of the axial clearances formed between the stationary member and the inner ring, between the inner ring and the output shaft, and between the output shaft and the stationary member. A clutch unit characterized in that the two surfaces forming the axial clearance are in contact with each other in all other axial clearances . 2. The stationary member comprises a side plate and a cover, and the spacer is interposed between the side plate and the output shaft, between the cover and the inner ring, or between the output shaft and the inner ring. Clutch unit as described. 3. A clutch unit according to claim 1, wherein said spacer is either a plate member or an elastic member. The clutch unit according to any one of claims 1 to 3, wherein said input side clutch portion and said output side clutch portion are incorporated in an automotive seat lifter portion.

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