One-way clutch

Abstract

Conventional one-way clutches have a structure that involves a damper spring between the input shaft and the output shaft, which could lead to a large and bulky structure. [Solution] An input plate 3 connected to an input shaft 2 and an output plate 5 connected to an output shaft 4 are arranged opposite each other. A strut 6, whose tip can protrude from and retract relative to the other plate 5, is housed in either the input plate 3 or the output plate 5. The strut 6 is housed in one of the plates 3 so as to be swingable and so as to be able to move back and forth in the axial direction. The one-way clutch 1 is equipped with an elastic body 11 that applies a repulsive force in two directions: a swinging direction that causes the tip of the strut 6 to protrude, and a forward direction that presses the base end of the strut 6 toward the other plate 5. This reduces torque shock while maintaining a compact and lightweight structure.

Description

Technical Field

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[0001] The present invention relates to a one-way clutch used in various power transmission mechanisms.

Background Art

[0002] ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The one-way clutch according to the present invention has an input plate connected to an input shaft and an output plate connected to an output shaft, which are arranged opposite each other, and a strut is housed in either the input plate or the output plate, the strut being able to protrude and retract from the other plate. This one-way clutch is characterized in that the strut is housed in one plate so as to be able to swing and move back and forth in the axial direction, and is provided with an elastic body that applies a repulsive force in two directions: a swinging direction that causes the tip of the strut to protrude, and a forward direction that presses the base end of the strut toward the other plate. [Effects of the Invention]

[0007] By adopting the above configuration, the one-way clutch according to the present invention can reduce torque shock while maintaining a compact and lightweight design. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional diagram illustrating a first embodiment of a one-way clutch according to the present invention. [Figure 2] Figure 1 shows an enlarged plan view (A) of the main part of the one-way clutch and a perspective view showing the torsion coil spring as an elastic body. [Figure 3] This is a side view showing the contact area between the base end of the strut and the elastic body. [Figure 4] This is a cross-sectional diagram illustrating a state where only the input plate rotates. [Figure 5] This is a cross-sectional diagram illustrating the state in which the input and output plates rotate synchronously. [Figure 6] This is an explanatory diagram showing the change in the inclination angle of the strut. [Figure 7] This is an explanatory diagram of the key parts showing the relationship between the inclination angle of the strut and the inclined surface of the recess. [Modes for carrying out the invention]

[0009] <First Embodiment> The one-way clutch 1 shown in Figure 1 has an input plate 3 connected to an input shaft 2 and an output plate 5 connected to an output shaft 4, which are arranged coaxially opposite each other. A strut 6, whose tip can protrude from and retract into the other plate, is housed in either the input plate 3 or the output plate 5. In this embodiment, one plate is the input plate 3 and the other plate is the output plate.

[0010] The illustrated one-way clutch 1 includes a housing 7 that accommodates an input plate 3 and an output plate 5, and bearings 8 and 9 provided in the housing 7 rotatably hold the input shaft 2 and the output shaft 4, respectively.

[0011] Both the input plate 3 and the output plate 5 are circular in shape when viewed from the axial direction, and multiple recesses 3A and 5A are arranged at equal intervals in the circumferential direction on their opposing surfaces. In Figure 1, the multiple recesses 3A and 5A are shown in a planar view for ease of understanding, but in reality, the recesses 3A and 5A are arranged along the circumferential direction.

[0012] The input plate 3 is fixed to the end of the input shaft 2, which passes through the output plate 5. The output plate 5 is connected to a holder 10, which is connected to the end of the output shaft 4. The holder 10 has a disc portion 10A connected to the output shaft 4 and an annular portion 10B that is continuous with the periphery of the disc portion 10A, and the output plate 5 is fixed so as to close the opening of the annular portion 10B. As a result, the input plate 3 is housed between the output plate 5 and the disc portion 10A of the holder 10.

[0013] The one-way clutch 1 described above houses a strut 6 in each recess 3A of the input plate 3 so as to be able to swing and move back and forth in the axial direction, and is equipped with an elastic body 11 that applies a repulsive force in two directions: a swinging direction in which the tip of the strut 6 protrudes, and a forward direction in which the base of the strut 6 is pressed toward the output plate.

[0014] The strut 6 is not limited in its shape or the like, but as an example, it is a square bar-shaped member. As shown in Fig. 2(A), by passing the pin 14 fixed to the recess 3A through the insertion hole 6A formed in the middle in the axial direction, it can swing around the pin 14. Further, the strut 6 has a long hole in which the insertion hole 6A extends in the axial direction (longitudinal direction), and thereby, it can move forward and backward in the axial direction by the length of the insertion hole 6A.

[0015] Furthermore, the strut 6 has the insertion hole 6A closer to the base end portion than the central portion in the axial direction, and the pin 14 is passed through this insertion hole 6A. Therefore, the strut 6 has a swing center closer to its base end portion.

[0016] The elastic body 11 is a torsion coil spring shown in Fig. 2(B), and includes a pair of coil portions 11A, 11A arranged coaxially, a pair of first arms 11B, 11B respectively continuous with one end (outer end) of each coil portion 11A, 11A, and a second arm 11C continuous with the other end (inner end) of both coil portions 11A. This elastic body 11 is positioned such that each of both coil portions 11A and both first arms 11B is within the recess 3A on the input plate 3 side.

[0017] The above elastic body 11 arranges the coil portions 11A, 11A on both sides of the spring seat 12 provided in the recess 3A, inserts a holding pin 13 passing through the spring seat 12 into the coil portions 11A, 11A, and makes the pair of first arms 11B, 11B abut against the bottom surface of the recess 3A, thereby positioning it within the recess 3A.

[0018] And as shown in Fig. 3, the elastic body 11 has the second arm 11C pressing obliquely against the corner portion 6B at the base end portion of the strut 6. The corner portion 6B of the strut 6 is a chamfered curved surface, and in a more desirable embodiment, it is a curved surface having a constant curvature.

[0019] Furthermore, as shown in FIGS. 4 and 5, the one-way clutch 1 described above has a recess 5A formed in the output plate 5 into which the tip of the strut 6 projects. The recess 5A has an engagement surface 5B on one end side in the rotational direction of the output plate 5 (the left end side in FIGS. 4 and 5) against which the tip surface of the strut 6 abuts, and has an inclined surface 5C on the other end side in the rotational direction of the output plate 5 (the right end side in FIGS. 4 and 5) that gradually reduces the depth of the recess 5A.

[0020] And the inclined surface 5C has a length corresponding to at least the longitudinal dimension of the strut 6 in the rotational direction of the output plate 5. Also, as a more preferred embodiment, the inclined surface 5C has an inclination angle that changes at an angle always smaller than the inclination angle of the strut 6 with respect to the change in the inclination angle of the strut that gradually decreases by sliding contact with the inclined surface 5C in a state where the input plate 3 is rotating in the rotational direction in which the tip surface of the strut 6 is separated from the engagement surface 5B of the output plate 5 (the state shown in FIG. 4).

[0021] FIG. 6 shows a change line Ls of the inclination angle of the strut 6 that slidably contacts the inclined surface 5C. As shown in FIG. 4, as the input plate 3 rotates, the strut 6 rotates so as to fall while slidably contacting the inclined surface 5C with its tip, and thus the inclination angle gradually decreases. The change line Ls is a line connecting the corners (the corners on the recess 5A side) of the tip of the oscillating strut 6. In contrast, the inclined surface 5C has an inclination angle that changes at an angle always smaller than the inclination angle of the strut 6, and when the change line Ls is a curve as in the illustrated example, as shown in FIG. 7, it has a radius of curvature smaller than that of the change line Ls.

[0022] In the one-way clutch 1 with the above configuration, when the input shaft 2 is rotated forward (rotation in the direction of the white arrow in Figure 1), as shown in Figure 4, the tip surface of the strut 6 separates from the engagement surface 5B of the output plate 5, and the strut 6 oscillates in the retraction direction against the repulsive force of the elastic body 11 due to contact with the inclined surface 5C of the output plate 5. As a result, when the input shaft 2 is rotated forward, the one-way clutch 1 causes each strut 6 to move away (retract) as the input plate 3 rotates, so rotation is not transmitted to the output plate 5 and the output shaft 4.

[0023] In the one-way clutch described above, when the input shaft 2 is rotated in the reverse direction (rotation in the direction of the black arrow in Figure 1), as shown in Figure 5, the tip surface of the strut 6, which is in a protruding state due to the elastic body 11, comes into contact with the engagement surface 5B of the output plate 5, and the engagement state of both is maintained. As a result, the output plate 5 rotates together with the input plate 3, as shown by arrows A1 and A2 in Figure 1, and rotation is transmitted to the output shaft 4.

[0024] In this case, when the input shaft 2 is rotated forward, the one-way clutch 1 functions as a return spring, as shown in Figure 4, by having the elastic body 11 press the strut 6 in a swinging direction so that its tip protrudes, and also by pressing the strut 6 in the forward direction. When the input shaft 2 is rotated backward, as shown in Figure 5, the one-way clutch 1 maintains the protruding state of the strut 6 with the elastic body 11, and absorbs the load applied to the strut 6 in the direction of the base end, thereby reducing torque shock.

[0025] Thus, the one-way clutch 1 described above achieves both the return function and shock absorption function of the strut 6 with only one elastic body 11 in the input plate 3, thereby reducing torque shock while maintaining a compact and lightweight structure.

[0026] Such a one-way clutch 1 is used, for example, in a four-wheel drive electric vehicle to switch to a four-wheel drive state (clutch on) at high speed when slippage occurs while driving in two-wheel drive mode. In this case, the output shaft 4 is rotationally driven and the switching is performed in synchronization with the input shaft 2. At this time, the above-mentioned one-way clutch 1 is small and lightweight and can reduce torque shock, making it extremely useful for application to the drive wheel switching device described above.

[0027] Furthermore, by employing a torsion coil spring as the elastic body 11, the one-way clutch 1 described above can achieve structural simplification, reduction in the number of parts, and reduction in manufacturing costs. In addition, by making the corner portion 6B of the strut 6 that the second arm 11C of the torsion coil spring presses against in the one-way clutch 1 described above a chamfered curved surface, the repulsive force of the elastic body 11 can be reliably distributed in two directions: the direction that causes the strut 6 to protrude and the direction that causes it to move forward, while preventing stress concentration and ensuring smooth operation of the strut 6.

[0028] Furthermore, in the above-described one-way clutch, the corner 6B of the strut 6 is a curved surface with a constant curvature. If the corner 6B is a right angle, stress concentrates at the corner 6B, and the magnitude of the force (vector) acting in the oscillation direction and axial direction changes with the change in the inclination angle of the strut 6. In contrast, in the above-described one-way clutch 1, by making the corner 6B a curved surface with a constant curvature, stress concentration is avoided, and as shown in Figure 3, the magnitude of the force acting in the oscillation direction and axial direction of the strut 6 can always be kept constant, regardless of the inclination angle of the strut 6.

[0029] Furthermore, the one-way clutch 1 described above reduces the rotational moment on the elastic body 11 side (the side with the base end) by positioning the pivot point of the strut 6 closer to the base end, even when using a spring with a strong repulsive force as the elastic body 11. This reduces the pressure on the output plate 5, thereby achieving a reduction in friction.

[0030] Furthermore, the one-way clutch 1 described above has an inclined surface 5C in the recess 5A of the output plate that has a length at least equivalent to the longitudinal dimension of the strut 6, thereby obtaining a moment that exceeds the repulsive force of the elastic body 11. In particular, by making the angle of the inclined surface 5C always smaller than the inclination angle of the strut 6, only the corner of the tip of the strut 6 contacts the inclined surface 5C. In other words, surface contact between the side of the strut 6 and the inclined surface 5C is avoided, thereby achieving further reduction of friction and suppression of impact noise.

[0031] In the first embodiment described above, the input plate 3 was exemplified as one plate and the output plate 5 as the other plate. However, it is also possible to use the output plate 5 as one of the plates. In this case, struts and elastic bodies are arranged on the output plate, and recesses are provided on the input plate for the struts to engage with and disengage.

[0032] The configuration of the one-way clutch according to the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the present invention. [Explanation of Symbols]

[0033] 1. One-way clutch 2 Input axes 3. Input plate (one of the plates) 3A Recess 4 Output shafts 5. Output plate (the other plate) 5A Recess 5B Engagement surface 5C Slope 6 strut 6B Corner 11 Elastic body 11A Coil Section 11B First Arm 11C 2nd Arm

Claims

1. In a one-way clutch having an input plate connected to an input shaft and an output plate connected to an output shaft arranged opposite each other, and a strut whose tip can protrude from and retract into the other plate, the input plate and the output plate are housed in either the input plate or the output plate, The strut is housed in one of the aforementioned plates so as to be able to swing and move back and forth in the axial direction, A one-way clutch characterized by having an elastic body that applies a repulsive force in two directions: a swinging direction that causes the tip of the strut to protrude, and a forward direction that presses the base end of the strut toward the output plate.

2. The elastic body is a torsion coil spring comprising a coil portion, a first arm continuous with one end of the coil portion, and a second arm continuous with the other end of the coil portion. The coil portion and the first arm are positioned on the side of the one plate. The second arm is pressed against the corner of the base end of the strut, The one-way clutch according to claim 1, characterized in that the corner portion of the strut has a chamfered curved surface.

3. The one-way clutch according to claim 2, characterized in that the curved surface of the strut has a constant curvature.

4. The one-way clutch according to claim 2, characterized in that the strut has a pivot center near its base end.

5. The other plate has a recess into which the tip of the strut protrudes, The recess has an engagement surface on one end of the other plate in the rotational direction, against which the tip surface of the strut abuts, and on the other end of the other plate in the rotational direction, an inclined surface that gradually reduces the depth of the recess. The one-way clutch according to claim 2, characterized in that the inclined surface has a length corresponding to at least the longitudinal dimension of the strut in the rotational direction of the other plate.

6. In a state where the one plate is rotating in a rotational direction such that the tip surface of the strut is separated from the engagement surface of the other plate, The one-way clutch according to claim 5, characterized in that the inclined surface has an inclination angle that is always smaller than the inclination angle of the strut, with respect to the change in the inclination angle of the strut, which gradually decreases as the strut slides into contact with the inclined surface.

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