Clutch unit

Abstract

To preferably maintain a lock state.SOLUTION: A clutch unit 10 includes: an input-side clutch part 11 for controlling transmission and block of input rotational torque; and an output-side clutch part 12 which transmits the rotational torque input from the input-side clutch part 11 to the output side, and blocks the rotational torque reversely input from the output side. The output-side clutch part 12 includes: a stationary member 23 in which rotation is constrained; an output member 22 for outputting the rotational torque; a plurality of engagement parts 27 provided in a wedge gap between the stationary member 23 and the output member 22; an elastic member that urges the engagement part to a narrow-width side of the wedge gap; and a grease filled in a gap between the stationary member 23 and the output member 22. The grease contains a thickener made of calcium sulfonate.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a clutch unit. [Background technology]

[0002] 2. Description of the Related Art Known clutch units used in automobile seat lifters and the like transmit rotational torque input to an input member to an output member while blocking the transmission of reverse input rotational torque from the output member to the input member.

[0003] Generally, this type of clutch unit includes engagers such as sprags or rollers that engage with both the stationary member and the output member to interrupt the transmission of reverse input rotational torque.

[0004] When no rotational torque is input to the input member, the engagement of the engagement element with the stationary member and the output member restricts the rotation of the output member. Therefore, even if a reverse input rotational torque is input to the output member, the rotation of the output member is restricted and the transmission of the reverse input rotational torque to the input member is blocked.

[0005] On the other hand, when a rotational torque is input to the input member, the engagement of the engagement element is released as the input member rotates, thereby enabling the rotational torque to be transmitted from the input member to the output member.

[0006] Here, in a clutch unit having an engaging element as described above, grease is filled between the output member and the stationary member to reduce wear and frictional resistance between sliding surfaces, such as between the engaging element and the output member when the output member rotates and between the engaging element and the stationary member.

[0007] For example, Patent Document 1 (Japanese Patent No. 4278844) lists a lithium-based grease as an example of the grease used in a clutch unit for a seat lifter. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 4278844 Summary of the Invention [Problem to be solved by the invention]

[0009] When the grease has high lubricity, it is possible to effectively reduce wear and friction between the sliding surfaces, and also to easily release the engagement of the engagement element with the stationary member and the output member, improving operability when unlocking. However, on the other hand, if the engagement of the engagement element is easily released, there is a risk that the locked state cannot be maintained when a reverse input rotational torque is input. For example, in the case of a seat lifter, if the load generated when a passenger sits on the seat acts as a reverse input rotational torque, the locked state cannot be maintained, and the reverse input torque is transmitted, which may cause the seat surface position of the seat to drop.

[0010] The lithium-based grease mentioned in Patent Document 1 above is excellent in terms of maintaining lubricity in high-temperature environments such as midsummer. However, because the lithium soap contained as a thickening agent has self-lubricating properties, there is a concern that the static friction force (static friction coefficient) between the engaging element and the output member, and between the engaging element and the stationary member, may become too low.

[0011] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to ensure static friction between the engagement element and the output member, and between the engagement element and the stationary member, so as to be able to maintain the locked state favorably. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides a clutch unit comprising an input side clutch portion which controls the transmission and interruption of input rotational torque, and an output side clutch portion which transmits the rotational torque input from the input side clutch portion to the output side and interrupts the rotational torque input inversely from the output side, wherein the output side clutch portion has a stationary member whose rotation is restricted, an output member which outputs the rotational torque, a plurality of engaging members arranged in a wedge gap between the stationary member and the output member, an elastic member which biases the engaging members toward the narrow side of the wedge gap, and grease filled between the stationary member and the output member, wherein the grease contains a calcium sulfonate thickener.

[0013] In this way, in the clutch unit according to the present invention, by using a grease containing calcium sulfonate, it is possible to increase the static friction force (static friction coefficient) between the engaging element and the stationary member and between the engaging element and the output member, compared to the case where a lithium-based grease is used. This makes it difficult for the engaging element to be released from the stationary member and the output member (locked state), so that the locked state can be well maintained.

[0014] The grease may contain a solid lubricant in addition to the calcium sulfonate thickener. By adding a solid lubricant, the static friction force necessary to maintain the locked state can be secured while the static friction force can be adjusted so that it does not become too large, thereby improving operability.

[0015] The solid lubricant is preferably molybdenum disulfide, polytetrafluoroethylene, or melamine cyanurate. By using such a solid lubricant, it is possible to maintain the locked state while improving operability.

[0016] The particle diameter of the fine particles contained in calcium sulfonate is preferably 0.1 μm to 0.2 μm. By using calcium sulfonate having fine particles of such a particle diameter as a thickener, the static friction force between the engaging element and the stationary member, and between the engaging element and the output member can be more reliably secured, and the locked state can be well maintained.

[0017] The ratio of calcium sulfonate in the grease is preferably 16% or more and 20% or less. When a grease with such a calcium sulfonate content is used, the static friction force between the engaging element and the stationary member, and between the engaging element and the output member can be more reliably secured, and the locked state can be well maintained.

[0018] It is preferable that the surface roughness Ra of the engaging member is 0.01 μm or more and 0.20 μm or less, the surface roughness Ra of the stationary member in the wedge gap is 0.04 μm or more and 0.60 μm or less, and the surface roughness Ra of the output member in the wedge gap is 0.20 μm or more and 2.5 μm or less. By setting the surface roughness Ra in such a manner, the above-mentioned effects of the present invention can be obtained more reliably.

[0019] Moreover, the input clutch portion and the output clutch portion according to the present invention can be incorporated into a seat lifter portion for an automobile. Effect of the Invention

[0020] According to the present invention, the locked state can be maintained well. [Brief description of the drawings]

[0021] [Figure 1] 1 is a diagram showing the configuration of a seat and a seat lifter portion of an automobile; [Diagram 2] 1 is a vertical cross-sectional view showing an overall configuration of a clutch unit according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a right side view of FIG. 2. [Figure 4] FIG. 3 is a left side view of FIG. 2. [Diagram 5] FIG. 3 is a cross-sectional view taken along line AA in FIG. [Figure 6] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 7] 1A is a cross-sectional view of the side plate on the lever side, and FIG. [Figure 8] 1A is a cross-sectional view of the outer ring on the lever side, FIG. 1B is a left side view of FIG. 1A, and FIG. 1C is a right side view of FIG. [Figure 9] 1A is a cross-sectional view of the inner ring, and FIG. 1B is a left side view of FIG. [Figure 10] FIG. [Figure 11] (a) is a cross-sectional view of the cage, (b) is a left side view of (a), and (c) is a cross-sectional view of (a). [Figure 12] FIG. 13 is a perspective view of an inner centering spring. [Figure 13] FIG. 13 is a perspective view of an outer centering spring. [Figure 14] 1A is a perspective view of the output shaft as seen from one side, and FIG. 1B is a perspective view of the output shaft as seen from the other side. [Figure 15] (a) is a cross-sectional view of the output shaft, (b) is a left side view of (a), and (c) is a right side view of (a). [Figure 16] 1A is a cross-sectional view of the brake-side outer ring, and FIG. 1B is a left side view of FIG. [Figure 17] 1A is a cross-sectional view of the cover, and FIG. 1B is a right side view of FIG. [Figure 18] 1A is a cross-sectional view of the brake side plate, and FIG. 1B is a right side view of FIG. [Figure 19] (a) is a front view of the friction ring, (b) is a left side view of (a), and (c) is a right side view of (a). [Figure 20] FIG. 3 is a cross-sectional view taken along line CC in FIG. [Figure 21] FIG. 4 is a perspective view showing a state in which a brake-side outer ring and a cover are assembled to the brake-side side plate. [Figure 22]FIG. 4A is a perspective view showing a state in which the brake-side side plate is crimped to the brake-side outer ring and the cover, and FIG. 4B is a perspective view showing the state shown in FIG. [Figure 23] 4 is an enlarged cross-sectional view of a main portion showing a leaf spring and a cylindrical roller during operation of a brake-side clutch portion. FIG. [Figure 24] FIG. 2 is an enlarged cross-sectional view showing calcium sulfonate-containing grease interposed between a cylindrical roller and a brake-side outer ring, and between a cylindrical roller and an output shaft. [Diagram 25] FIG. 2 is an enlarged cross-sectional view showing the lithium soap-containing grease interposed between the cylindrical roller and the brake-side outer ring, and between the cylindrical roller and the output shaft. [Figure 26] FIG. 2 is a diagram showing the relative values ​​of the friction coefficients of a grease containing lithium soap and a grease containing calcium sulfonate. [Figure 27] FIG. 2 is a schematic diagram of a test device for measuring the coefficient of friction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An embodiment of a clutch unit according to the present invention will be described in detail with reference to the drawings. In the following embodiment, a clutch unit incorporated in a seat lifter for an automobile is illustrated. Note that the present invention is not limited to a clutch unit incorporated in a seat lifter for an automobile, but can also be applied to a clutch unit incorporated in other devices or equipment.

[0023] First, with reference to FIG. 1, the configuration of a seat lifter portion for an automobile in which the clutch unit according to this embodiment is incorporated will be described.

[0024] The seat lifter section 39 shown in FIG. 1 includes an operating lever 43 that is operated by a passenger such as a driver when adjusting the seat height of a seat 40, a clutch unit 10 that transmits input torque from the operating lever 43 and blocks reverse input from the output side, a sliding movable member 44 provided below the seat 40 (on the floor surface), and link members 45, 46 that are rotatably connected to the sliding movable member 44 and the seat 40.

[0025] The operating lever 43 is attached to the lever-side side plate 13 of the clutch unit 10, and when the operating lever 43 is rotated, the rotational torque at that time is transmitted to the output shaft 22 of the clutch unit 10. For example, to lower the seat surface of the seat 40, the operating lever 43 of the seat lifter portion 39 is rotated downward, and the output shaft 22 of the clutch unit 10 rotates in the direction of the arrow in FIG. 1. The output shaft 22 of the clutch unit 10 is provided with a pinion gear 41g that meshes with a sector gear 47 of a link member 45, and when the output shaft 22 rotates, the rotational torque is transmitted to the link member 45 via the pinion gear 41g. As a result, the link members 45, 46 tilt as shown by the dashed lines in the figure, and the seat surface of the seat 40 is lowered.

[0026] Conversely, when the operating lever 43 is rotated upward, the seat surface of the seat 40 becomes higher by a movement in the opposite direction to the above-mentioned movement.

[0027] Next, the overall configuration of the clutch unit according to this embodiment will be described with reference to Fig. 2 to Fig. 6. Fig. 2 is a vertical cross-sectional view showing the overall configuration of the clutch unit according to this embodiment, Fig. 3 is a right side view of Fig. 2, and Fig. 4 is a left side view of Fig. 2. Fig. 5 is a cross-sectional view taken along line AA in Fig. 2, and Fig. 6 is a cross-sectional view taken along line BB in Fig. 2.

[0028] As shown in FIG. 2, the clutch unit 10 of this embodiment includes a lever side clutch portion 11 as an input side clutch portion that controls the transmission and cut-off of the input rotational torque, and a brake side clutch portion 12 as an output side clutch portion that transmits the rotational torque input from the lever side clutch portion 11 to the output side and cuts off the rotational torque input inversely from the output side.

[0029] The lever side clutch section 11 has as its main components a lever side side plate 13, a lever side outer ring 14, an inner ring 15, a plurality of cylindrical rollers 16, a cage 17, an inner centering spring 18, and an outer centering spring 19. On the other hand, the brake side clutch section 12 has as its main components an inner ring 15, an output shaft 22, a brake side outer ring 23, a cover 24, a brake side side plate 25, a plurality of cylindrical rollers 27, a leaf spring 28 (see FIG. 6), and a friction ring 29. In FIG. 2, the member indicated by the reference numeral 30 and the member indicated by the reference numeral 31 are a wave washer and a washer that are attached to the outer circumferential surface of the output shaft 22. The washer 31 is press-fitted into the end of the output shaft 22 via the wave washer 30, thereby preventing the components from coming off the output shaft 22. In the following description, the direction parallel to the rotation axis of the output shaft 22 is referred to as the "axial direction," and the direction intersecting the rotation axis (including the direction perpendicular thereto) is referred to as the "radial direction." Additionally, the circumferential direction of a circle centered on the rotation axis of the output shaft 22 is referred to as the "circumferential direction."

[0030] The operating lever 43 (see FIG. 1) is attached to the lever-side side plate 13. The lever-side side plate 13 is also connected to the lever-side outer wheel 14, so that when a rider rotates the operating lever 43, the lever-side side plate 13 and the lever-side outer wheel 14 rotate together to input a rotational torque. That is, the lever-side side plate 13 and the lever-side outer wheel 14 function as an input member that inputs a rotational torque. The connecting structure between the lever-side side plate 13 and the lever-side outer wheel 14 will be described in detail later.

[0031] The inner ring 15 functions as a torque transmission member that transmits the rotational torque input from the lever side outer ring 14 to the brake side clutch section 12. A wedge gap 20 (see FIG. 5) is formed between the outer peripheral surface 15a of the inner ring 15 and the inner peripheral surface (cam surface 14a) of the lever side outer ring 14, and a plurality of cylindrical rollers 16 are arranged in this wedge gap 20 as engaging elements. The cylindrical rollers 16 control the transmission and interruption of the rotational torque from the lever side outer ring 14 by engaging and disengaging with the outer peripheral surface 15a of the inner ring 15 and the inner peripheral surface (cam surface 14a) of the lever side outer ring 14 in the wedge gap 20. The plurality of cylindrical rollers 16 are held at equal intervals in the circumferential direction by a cage 17.

[0032] The inner centering spring 18 is a first elastic member for returning the cage 17 to a neutral state. When a rotational torque is input from the lever-side outer ring 14, an elastic force is accumulated in the inner centering spring 18 as the lever-side outer ring 14 rotates. After that, when the input torque from the lever-side outer ring 14 is released, the inner centering spring 18 returns the cage 17 to the neutral state by its elastic restoring force.

[0033] The outer centering spring 19 is another elastic member located on the outer diameter side of the inner centering spring 18, and functions as a second elastic member for returning the lever side outer ring 14 to a neutral state. When a rotational torque is input from the lever side outer ring 14, an elastic force is accumulated in the outer centering spring 19 as the lever side outer ring 14 rotates. Then, when the input torque from the lever side outer ring 14 is released, the outer centering spring 19 returns the lever side outer ring 14 to the neutral state by its elastic restoring force.

[0034] The output shaft 22 functions as an output member that outputs rotational torque. The output shaft 22 is disposed radially inside the brake-side outer ring 23 and rotatably supported. On the other hand, the brake-side outer ring 23, the cover 24, and the brake-side side plate 25 are members whose rotation is restricted and function as stationary members.

[0035] A wedge gap 26 (see FIG. 6) is formed between the inner peripheral surface 23b of the brake side outer ring 23 and the outer peripheral surface (cam surface 22a) of the output shaft 22, and multiple pairs of cylindrical rollers 27 are arranged in the wedge gap 26 as engaging elements. The detailed function will be described later, but the multiple pairs of cylindrical rollers 27 transmit the input torque from the inner ring 15 and block the reverse input torque from the output shaft 22 by engaging and disengaging with the inner peripheral surface 23b of the brake side outer ring 23 and the outer peripheral surface (cam surface 22a) of the output shaft 22 between the brake side outer ring 23 and the output shaft 22 (wedge gap 26). In addition, a leaf spring 28 is arranged between each pair of cylindrical rollers 27 as an elastic member (see FIG. 6). The leaf spring 28 presses the cylindrical rollers 27 on both sides in a direction away from each other, and urges each cylindrical roller 27 toward the narrow side of the wedge gap 26. Instead of the leaf spring 28, other elastic members such as a coil spring may be used.

[0036] In addition, a friction ring 29 is fixed to the brake-side side plate 25. The friction ring 29 is disposed so as to come into contact with (slide relatively to) the rotating output shaft 22, and applies rotational resistance to the output shaft 22.

[0037] Next, the main components of the lever side clutch portion 11 and the brake side clutch portion 12 according to this embodiment will be described in detail.

[0038] 7A and 7B are diagrams showing the configuration of the lever-side side plate 13. (a) is a cross-sectional view of the lever-side side plate 13, and (b) is a left side view of (a).

[0039] As shown in FIG. 7, the lever-side side plate 13 has a hole 13a formed in its center through which the output shaft 22 and the inner ring 15 are inserted. In addition, a plurality of (for example, five) claws 13b are protrudingly provided on the outer peripheral edge of the lever-side side plate 13. These claws 13b are bent in the axial direction, and the tip of the bent part is formed in a bifurcated shape and is inserted into a recess 14e of the lever-side outer ring 14 described later (see FIG. 5). In a state in which the claws 13b are inserted into the recess 14e, the bifurcated tip of the claws 13b is expanded outward, so that the lever-side side plate 13 is fixed to the lever-side outer ring 14 by crimping. In addition, the lever-side side plate 13 has a plurality of (for example, four) holes 13c through which the operating lever 43 is attached.

[0040] 8 is a diagram showing the configuration of the lever side outer ring 14. (a) is a cross-sectional view of the lever side outer ring 14, (b) is a left side view of (a), and (c) is a right side view of (a).

[0041] 8, the lever-side outer ring 14 has a cylindrical portion 14d extending in the axial direction and an annular portion 14c expanding radially outward from one axial end of the cylindrical portion 14d. A hole 14b through which the output shaft 22 and the inner ring 15 are inserted is formed on the radially inner side of the cylindrical portion 14d. In addition, a plurality of cam surfaces 14a are formed at equal intervals in the circumferential direction on the inner peripheral surface of the cylindrical portion 14d.

[0042] A plurality of (e.g., three) claws 14f, 14g protruding in the axial direction are provided on the outer peripheral edge of the annular portion 14c. Of these claws 14f, 14g, one claw 14f is a portion that engages the outer centering spring 19, and the remaining two claws 14g are portions that function as restriction portions that restrict the operation angle of the operating lever 43.

[0043] Further, on the outer circumferential surface of the annular portion 14c, there are formed a plurality of (five in the figure) recesses 14e into which the claw portions 13b (see FIG. 7) of the lever-side side plate 13 are inserted. The claw portions 13b of the lever-side side plate 13 are inserted into the recesses 14e, and the claw portions 13b are further tightened, thereby connecting the lever-side side plate 13 and the lever-side outer ring 14 (see FIG. 5). This allows the lever-side side plate 13 and the lever-side outer ring 14 to rotate together when a rotational torque is input.

[0044] 9 is a diagram showing the configuration of the inner ring 15. (a) is a cross-sectional view of the inner ring 15, and (b) is a left side view of (a).

[0045] As shown in Fig. 9, the inner ring 15 has a cylindrical portion 15b extending in the axial direction and an annular portion 15f expanding radially outward from one axial end of the cylindrical portion 15b. A hole 15g through which the output shaft 22 is inserted is formed on the radially inner side of the cylindrical portion 15b. In addition, the cylindrical portion 15b is inserted into the cylindrical portion 14d of the lever side outer ring 14 in a state where it is assembled in the clutch unit (see Fig. 2). In a state where the cylindrical portion 15b is inserted into the cylindrical portion 14d of the lever side outer ring 14, a wedge gap 20 in which the cylindrical roller 16 is disposed is formed between the cylindrical portions 15b, 14d (see Fig. 5).

[0046] The outer peripheral edge of the annular portion 15f is provided with a plurality of claw portions 15c (six in the figure) protruding in the axial direction. The plurality of claw portions 15c are provided at equal intervals in the circumferential direction, and the cylindrical rollers 27 and the leaf springs 28 are arranged between the claw portions 15c (see FIG. 6). That is, the inner ring 15 has pockets 15e between the claw portions 15c in which the cylindrical rollers 27 and the leaf springs 28 are accommodated, and functions as a retainer that holds the cylindrical rollers 27 and the leaf springs 28. The annular portion 15f is also provided with a plurality of holes 15d at equal intervals in the circumferential direction, into which the projections 22f (see FIG. 2) provided on the output shaft 22 are inserted. When the projections 22f of the output shaft 22 are inserted into the holes 15d, the projections 22f are arranged with a predetermined clearance from the holes 15d.

[0047] Figures 10 and 11 show the structure of the cage 17. Figure 10 is a perspective view of the cage 17, and in Figure 11, (a) is a cross-sectional view of the cage 17, (b) is a left side view of (a), and (c) is a cross-sectional view of (a).

[0048] 10 and 11, the cage 17 is a cylindrical member having a plurality of pockets 17a at equal intervals in the circumferential direction. Each of the pockets 17a accommodates one cylindrical roller 16 (see FIG. 5). Furthermore, two recesses 17b for engaging the inner centering spring 18 are formed at one axial end of the cage 17.

[0049] FIG. 12 is a perspective view of the inner centering spring 18.

[0050] As shown in Fig. 12, the inner centering spring 18 is formed by bending a wire rod having a circular cross section into a C-shape. A part of the inner centering spring 18 is bent radially inward to form a pair of locking portions 18a. As shown in Fig. 20, each locking portion 18a is locked to adjacent end faces 17c of two recesses 17b provided in the cage 17, whereby the inner centering spring 18 is locked to the cage 17.

[0051] FIG. 13 is a perspective view of the outer centering spring 19.

[0052] As shown in Fig. 13, the outer centering spring 19 is formed by bending a band-shaped member or the like into a C-shape. A part of the outer centering spring 19 is bent radially outward to form a pair of locking portions 19a. As shown in Fig. 20, the locking portions 19a are locked to the lever-side outer ring 14 by sandwiching the claw portions 14f provided on the lever-side outer ring 14.

[0053] Figures 14 and 15 are diagrams showing the configuration of the output shaft 22. In Figure 14, (a) is a perspective view of the output shaft 22 seen from one side, and (b) is a perspective view of the output shaft 22 seen from the other side. In Figure 15, (a) is a cross-sectional view of the output shaft 22, (b) is a left side view of (a), and (c) is a right side view of (a).

[0054] 14 and 15, the output shaft 22 has a shaft portion 22c and a large diameter portion 22d that expands radially outward from approximately the center of the shaft portion 22c. A pinion gear 41g that meshes with the sector gear 47 (see FIG. 1) of the link member 45 is coaxially provided at the tip of the shaft portion 22c.

[0055] A plurality of (for example, six) flat cam surfaces 22a are formed at equal intervals in the circumferential direction on the outer peripheral surface of the large diameter portion 22d. An annular recess 22b for accommodating a friction ring 29 is formed on one axial end face of the large diameter portion 22d, and a plurality of protrusions 22f to be inserted into each hole 15d of the inner ring 15 is provided on the opposite face (the other axial end face).

[0056] 16 is a diagram showing the configuration of the brake-side outer ring 23. (a) is a cross-sectional view of the brake-side outer ring 23, and (b) is a left side view of (a).

[0057] As shown in Fig. 16, the brake-side outer ring 23 is an annular member, and the large diameter portion 22d of the output shaft 22 is inserted into the radial inside of the brake-side outer ring 23 (see Fig. 2). When the large diameter portion 22d of the output shaft 22 is inserted into the brake-side outer ring 23, a wedge gap 26 in which a cylindrical roller 27 and a leaf spring 28 are disposed is formed between the inner peripheral surface 23b of the brake-side outer ring 23 and the outer peripheral surface (cam surface 22a) of the large diameter portion 22d (see Fig. 6). In addition, the outer peripheral surface of the brake-side outer ring 23 is formed with a plurality of recesses 23a (three in the figure) for coupling with the brake-side side plate 25.

[0058] 17A and 17B are diagrams showing the configuration of the cover 24. (a) is a cross-sectional view of the cover 24, and (b) is a right side view of (a).

[0059] 17, the cover 24 is an annular member having a hole 24c in the center through which the output shaft 22 is inserted. In addition, a plurality of recesses 24a (three in the figure) are formed on the outer circumferential surface of the cover 24 so as to correspond to the recesses 23a (see FIG. 16) of the brake-side outer ring 23. These recesses 24a are provided to connect the cover 24 and the brake-side side plate 25.

[0060] The cover 24 is provided with two claws 24b, 24d for engaging the inner centering spring 18 and the outer centering spring 19. One of the claws 24b is a claw for engaging the inner centering spring 18, and is provided so as to protrude in the axial direction radially inward from the outer circumferential surface of the cover 24. On the other hand, the other claw 24d is a claw for engaging the outer centering spring 19, and is provided so as to protrude in the axial direction from the outer circumferential surface of the cover 24 at a position 180° different from the one claw 24b (the opposite side in the circumferential direction across the hole 24c).

[0061] 20, the claw portion 24b for the inner centering spring is disposed so as to be sandwiched between the two locking portions 18a of the inner centering spring 18, thereby locking the inner centering spring 18 to the cover 24. Also, as shown in FIG 20, the claw portion 24d for the outer centering spring is disposed so as to be sandwiched between the two locking portions 19a of the outer centering spring 19, thereby locking the outer centering spring 19 to the cover 24.

[0062] 17, two sets of locking portions 24e, 24f are provided on the outer circumferential surface of the cover 24. These two sets of locking portions 24e, 24f are portions that function as rotation stoppers that restrict the rotation of the lever-side outer ring 14 when the lever-side outer ring 14 is rotated by operating the operating lever 43, with the claw portions 14g (see FIG. 8) of the lever-side outer ring 14 hitting against them. This restricts the operating angle of the operating lever 43.

[0063] 18 is a diagram showing the configuration of the brake-side side plate 25. (a) is a cross-sectional view of the brake-side side plate 25, and (b) is a right side view of (a).

[0064] As shown in FIG. 18, the brake-side side plate 25 is a plate-like member having a hole 25b in the center through which the output shaft 22 is inserted. On the outer peripheral surface of the brake-side side plate 25, a claw portion 25a is provided that protrudes in the axial direction for connecting with the brake-side outer ring 23 and the cover 24. A plurality of claw portions 25a (three in the figure) are provided corresponding to the recesses 23a, 24a of the brake-side outer ring 23 and the cover 24. As shown in FIG. 21, each claw portion 25a of the brake-side side plate 25 is inserted into each recess 23a, 24a of the brake-side outer ring 23 and the cover 24, and further, as shown in FIG. 22, the bifurcated tip portion 25a1 of each claw portion 25a is expanded outward, so that the brake-side side plate 25 is crimped and fixed to the brake-side outer ring 23 and the cover 24. As a result, the brake-side outer ring 23, the cover 24, and the brake-side side plate 25 are integrally connected to form a stationary side member.

[0065] 18, one flange 25e and two flanges 25f are provided on the outer peripheral edge of the brake-side side plate 25 as clutch attachment portions for the seat lifter portion. These three flanges 25e, 25f are provided with cylindrical portions 25i, 25j protruding in the axial direction, and each cylindrical portion 25i, 25j is provided with attachment holes 25g, 25h for the seat lifter portion. Around hole 25b in the center of brake-side side plate 25, a plurality of holes 25c for fixing friction ring 29 are provided at equal intervals in the circumferential direction.

[0066] 19 is a diagram showing the configuration of the friction ring 29. (a) is a front view of the friction ring 29, (b) is a left side view of (a), and (c) is a right side view of (a).

[0067] 19, the friction ring 29 is an annular member made of resin or the like, and has a plurality of circular projections 29a provided at equal intervals in the circumferential direction on one axial end face thereof. These projections 29a are press-fitted into the respective holes 25c (see FIG. 18) of the brake-side side plate 25, whereby the friction ring 29 is fixed to the brake-side side plate 25 (see FIG. 2).

[0068] The friction ring 29 is housed in the annular recess 22b of the large diameter portion 22d of the output shaft 22 while being fixed to the brake-side side plate 25 (see FIG. 2). In this state, the friction ring 29 is press-fitted with a tightening margin into the inner circumferential surface 22e of the annular recess 22b of the output shaft 22. Therefore, when the output shaft 22 rotates, a frictional force is generated between the outer circumferential surface 29c of the friction ring 29 and the inner circumferential surface 22e of the annular recess 22b, and a rotational resistance is applied to the output shaft 22.

[0069] The operations of the lever-side clutch portion 11 and the brake-side clutch portion 12 according to this embodiment will be described below.

[0070] First, when the operating lever 43 is rotated and a rotational torque is input to the lever side clutch portion 11, the lever side outer ring 14 rotates. When the lever side outer ring 14 rotates, the cylindrical roller 16 engages with the lever side outer ring 14 and the inner ring 15 between them (wedge gap 20) (see FIG. 5), and the rotational torque is transmitted from the lever side outer ring 14 to the inner ring 15 via the cylindrical roller 16. This causes the inner ring 15 to rotate. At this time, elastic forces are accumulated in both centering springs 18 and 19 as the lever side outer ring 14 and the retainer 17 rotate. After that, when the input of the rotational torque is eliminated, the lever side outer ring 14 and the retainer 17 return to a neutral state due to the elastic restoring forces of both centering springs 18 and 19, and the engagement of the cylindrical roller 16 between the lever side outer ring 14 and the inner ring 15 between them (wedge gap 20) is released. As a result, the transmission of rotational torque from the lever side outer ring 14 to the inner ring 15 via the cylindrical rollers 16 is blocked.

[0071] In this way, when the input of rotational torque is removed, the lever side outer ring 14 and the cage 17 return to the neutral state, while the inner ring 15 maintains the given rotational position. Therefore, by repeatedly rotating the operating lever 43, the inner ring 15 rotates in increments.

[0072] When the inner ring 15 rotates, as shown in Fig. 23, the claws 15c of the inner ring 15 push the cylindrical rollers 27 in the direction of the arrow in the figure against the elastic force of the leaf springs 28. Then, when the inner ring 15 rotates further, the holes 15d (see Fig. 9) of the inner ring 15 come into contact with the projections 22f (see Figs. 14 and 15) of the output shaft 22, and the rotational torque is transmitted from the inner ring 15 to the output shaft 22 via the projections 22f, causing the output shaft 22 to rotate.

[0073] When the operating lever 43 is rotated in the opposite direction, the output shaft 22 rotates in the opposite direction due to the same mechanism as the above operation.

[0074] In this way, when the output shaft 22 rotates clockwise (forward direction) or counterclockwise (reverse direction) by rotating the operating lever 43, the sector gear 47 (see FIG. 1) swings, and the seat height of the seat 40 is adjusted.

[0075] Furthermore, when a rotational torque is input in reverse from the output shaft 22 side, cylindrical rollers 27 arranged between the output shaft 22 and the brake side outer ring 23 (wedge gap 26) engage with the cam surface 22a of the output shaft 22 and the inner peripheral surface 23b of the brake side outer ring 23, thereby locking the output shaft 22 so that it does not rotate. As a result, the rotational torque input in reverse from the output shaft 22 is locked in the brake side clutch section 12, and is blocked from being transmitted to the lever side clutch section 11.

[0076] Thereafter, when the operating lever 43 is rotated again and a rotational torque is input from the lever-side outer ring 14, the cylindrical rollers 27 are pushed and moved by the rotation of the inner ring 15, and the engagement of the cylindrical rollers 27 in the wedge gap 26 is released, as shown in Fig. 23. This makes the output shaft 22 rotatable. Then, as the output shaft 22 rotates, the seat height of the seat 40 is adjusted.

[0077] In the clutch unit 10 according to this embodiment, grease is sealed in the internal spaces of the lever-side clutch portion 11 and the brake-side clutch portion 12, thereby ensuring lubrication between the sliding surfaces of these components. However, if the lubricity of the sealed grease is too high, the engagement of the cylindrical rollers 27 with the brake-side outer ring 23 and the output shaft 22 in the brake-side clutch portion 12 becomes more likely to be released, and there is a risk that the locked state cannot be maintained when a reverse input rotational torque is input.

[0078] For example, in the case of lithium-based grease, as shown in Fig. 25, the lithium soap 51 contained as a thickener has a fibrous structure consisting of many fibers 51 and has self-lubricating properties that make it easy for the fibers 51 to slip between each other, so there is a concern that the static friction force (static friction coefficient) between the cylindrical rollers 27 and the brake-side outer ring 23, and between the cylindrical rollers 27 and the output shaft 22, may become too low if lithium-based grease is present between them. In that case, there is a risk that the load (reverse input torque) applied when a passenger sits on the seat will release the engagement (locked state) of the cylindrical rollers 27 with the output shaft 22 and the brake-side outer ring 23, causing the seat surface position of the seat to drop.

[0079] Therefore, in the clutch unit 10 according to this embodiment, in order to prevent the release of the locked state due to the reverse input rotational torque as described above, the following measures are taken. The characteristic features of this embodiment will be described below.

[0080] <About grease thickeners> In this embodiment, grease containing calcium sulfonate as a thickener is used to prevent the static friction force between the cylindrical rollers 27 and the brake-side outer ring 23, and between the cylindrical rollers 27 and the output shaft 22 from becoming too low. The grease may be one made of a base oil and a thickener, or one made of a base grease made of a base oil and a thickener to which an additive has been added. The type of base oil is not particularly limited, and can be appropriately selected from known types.

[0081] 24, calcium sulfonate 60 is a thickener having many fine particles 61, and has lower self-lubrication properties than lithium soap 51 having a fibrous structure. Therefore, by interposing grease containing calcium sulfonate between cylindrical roller 27 and brake-side outer ring 23, and between cylindrical roller 27 and output shaft 22, the static friction force (static friction coefficient) between them can be increased compared to the case where lithium-based grease is used.

[0082] Figure 26 shows the relative values ​​of the friction coefficients of grease A containing lithium soap and grease B containing calcium sulfonate. Testing equipment 70 shown in Figure 27 was used to measure the friction coefficients of greases A and B. More specifically, in a room temperature environment, grease was applied to the outer circumferential surface of ring 71 and cylindrical rollers 72 were pressed against it, and the friction coefficient was measured from the value of the frictional resistance generated between ring 71 and cylindrical rollers 72 when ring 71 was rotated in this state. The same mineral oil was used as the base oil for both grease A and grease B.

[0083] As shown in Figure 26, the results of this test show that Grease B, which contains calcium sulfonate, has a higher friction coefficient than Grease A, which contains lithium soap. Specifically, the friction coefficient of Grease B was approximately 1.14 times that of Grease A. This confirms that even when the same base oil is used, the friction coefficient increases when calcium sulfonate is used as a thickener.

[0084] Therefore, by using grease containing calcium sulfonate as the grease for the clutch unit according to this embodiment, it is possible to increase the static friction force (static friction coefficient) between the cylindrical rollers 27 and the brake-side outer ring 23 and between the cylindrical rollers 27 and the output shaft 22, compared to the case where lithium-based grease is used. This makes it difficult for the engagement (locked state) of the cylindrical rollers 27 with the brake-side outer ring 23 and the output shaft 22 to be released, so that it is possible to prevent the locked state from being released when a passenger sits on the seat, and it becomes possible to maintain the seat position well.

[0085] The particle diameter of the fine particles 61 contained in the calcium sulfonate is preferably 0.1 μm or more and 0.2 μm or less. By using calcium sulfonate having fine particles of such a particle diameter as a thickening agent, the static friction force between the cylindrical rollers 27 and the brake-side outer ring 23, and between the cylindrical rollers 27 and the output shaft 22 can be more reliably secured, and the locked state can be well maintained.

[0086] The proportion of calcium sulfonate in the grease is preferably 16% or more and 20% or less. When grease with such a calcium sulfonate content is used, the static friction force between the cylindrical rollers 27 and the brake-side outer ring 23, and between the cylindrical rollers 27 and the output shaft 22 can be more reliably secured, and the locked state can be well maintained.

[0087] <About grease additives> As described above, in the clutch unit according to this embodiment, by using grease containing calcium sulfonate, it becomes difficult to release the locked state caused by the reverse input rotational torque. On the other hand, if it becomes difficult to release the locked state, it is considered that the operability when adjusting the seat height by operating the operating lever 43 decreases. Therefore, when the operating lever 43 is operated, it becomes difficult for the rotating inner ring 15 to push the cylindrical roller 27 out of the wedge gap 27, so it is necessary to increase the operating force of the operating lever 43.

[0088] Thus, in the present invention, since maintaining a good locked state results in a decrease in operability, it is preferable to add a solid lubricant to the calcium sulfonate-containing grease if one wishes to improve operability. By adding a solid lubricant, the static frictional forces between the cylindrical rollers 27 and the brake-side outer ring 23, and between the cylindrical rollers 27 and the output shaft 22 can be adjusted so as not to become too large, thereby improving operability while maintaining a good locked state.

[0089] The solid lubricant is preferably molybdenum disulfide, polytetrafluoroethylene (PTFE), or melamine cyanurate (MCA: Melamine Cyanuric Acid). By adding such a solid lubricant, it becomes possible to maintain the locked state while improving operability.

[0090] <Surface roughness> Furthermore, in order to ensure the effect of using the calcium sulfonate-containing grease as described above, it is preferable that the surface roughness Ra of each of the contact surfaces (sliding surfaces) of the cylindrical rollers 27, the brake side outer ring 23 and the output shaft 22 has the following value.

[0091] Surface roughness of cylindrical roller 27 Ra: 0.01μm to 0.20μm Surface roughness Ra of the inner circumferential surface 23b (see FIG. 6) in the wedge gap 26 of the brake-side outer ring 23: 0.04 μm or more and 0.60 μm or less Surface roughness Ra of the cam surface 22a (see FIG. 6) in the wedge gap 26 of the output shaft 22: 0.20 μm or more and 2.5 μm or less

[0092] By setting the surface roughness Ra as described above, the effects of the present invention (maintenance of the locked state, or maintenance of the locked state and improved operability) can be obtained more reliably, making it possible to provide a highly reliable clutch unit and automobile seat lifter.

[0093] Although each embodiment of the present invention has been described above, the present invention is not limited to the configurations of each of the above-described embodiments, and can be modified as appropriate without departing from the gist of the invention. [Explanation of symbols]

[0094] 10 Clutch unit 11 Lever side clutch part (input side clutch part) 12 Brake side clutch part (output side clutch part) 22 Output shaft (output member) 23 Brake side outer ring (stationary member) 26 Wedge gap 27 Cylindrical roller (engagement element) 28 Leaf spring (elastic member) 39 Seat lifter part 60 Calcium Sulfonate 61 Fine particles

Claims

1. A clutch unit including an input side clutch portion that controls transmission and interruption of an input rotational torque, and an output side clutch portion that transmits the rotational torque input from the input side clutch portion to an output side and interrupts the rotational torque input inversely from the output side, the output side clutch portion includes a stationary member whose rotation is restricted, an output member which outputs a rotational torque, a plurality of engaging elements disposed in a wedge gap between the stationary member and the output member, an elastic member which biases the engaging elements toward a narrower side of the wedge gap, and grease which is filled between the stationary member and the output member; 11. A clutch unit according to claim 10, wherein the grease contains a calcium sulfonate thickener.

2. 2. The clutch unit according to claim 1, wherein the grease contains a solid lubricant in addition to a calcium sulfonate thickener.

3. 3. The clutch unit according to claim 2, wherein the solid lubricant is molybdenum disulfide, polytetrafluoroethylene, or melamine cyanurate.

4. 4. The clutch unit according to claim 1, wherein the particle diameter of the fine particles contained in the calcium sulfonate is 0.1 μm or more and 0.2 μm or less.

5. 4. The clutch unit according to claim 1, wherein the content of the calcium sulfonate in the grease is 16% or more and 20% or less.

6. The surface roughness Ra of the engaging element is 0.01 μm or more and 0.20 μm or less, The surface roughness Ra of the stationary member in the wedge gap is 0.04 μm or more and 0.60 μm or less, 4. The clutch unit according to claim 1, wherein the surface roughness Ra of the output member in the wedge gap is 0.20 μm or more and 2.5 μm or less.

7. 4. The clutch unit according to claim 1, wherein the input clutch portion and the output clutch portion are incorporated in a seat lifter portion for an automobile.

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