JP4321981B2 - One-way clutch - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a one-way clutch and a one-way clutch unit, and particularly to miniaturization thereof.
[0002]
[Prior art]
As a one-way clutch used in a drive unit of an electric device or office device, the one shown in FIG. 5 has been conventionally known (for example, see Japanese Patent Application Laid-Open No. 9-89011). This one-way clutch is provided with several roller storage portions 24 on the inner diameter surface of the outer ring 22 fitted around the shaft 21, and a predetermined wedge angle between the shaft 21 and the bottom surface of each roller storage portion 24. A cam surface 25 is provided. Further, a spring accommodating recess 26 is provided at the enlarged side end of the roller accommodating portion 24.
[0003]
A roller 27 is housed in the roller housing portion 24, and a spring member 28 housed in the spring housing recess 26 is pressed against the roller 27, thereby urging the roller 27 in the narrow direction of the housing portion 24. 27 is stabilized.
[0004]
An outer ring 29 is fitted around the outer ring 22 in a state in which the rotation is stopped. The outer ring 29 closes one end surface in the axial direction of the roller storage portion 24 at one end surface thereof. The other end surface of the roller storage portion 24 is closed by a lid member (not shown).
[0005]
The one-way clutch is used by incorporating the outer ring 29 into a boss portion of a rotating member such as a gear, and when the shaft 21 and the outer ring 22 rotate in a relatively fixed direction (see arrow A in the figure) The roller 27 engages and locks the narrow side of the storage portion 24, and the shaft 21 and the torque limiter are integrated to transmit torque. When the rotation direction is the reverse direction, the roller 27 moves to the enlargement side of the storage portion 24. Therefore, the roller 27 becomes free and the one-way clutch rotates idly, and torque transmission is interrupted.
[0006]
[Problems to be solved by the invention]
In various devices that use the above one-way clutch (paper transport roller drive unit of a printer / copier, personal computer, portable information terminal, etc.), the one-way clutch is required to be downsized as the device main body is downsized. . However, in the conventional structure, since the outer diameter is always larger than the diameter of the shaft, there is a certain limit to downsizing.
[0007]
Accordingly, an object of the present invention is to provide a one-way clutch capable of solving such a problem and meeting the demand for downsizing.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an inner member, an outer ring fitted to the inner member so as to be relatively rotatable, a rolling element interposed between the inner member and the outer ring, and the rolling element in one direction. A rolling member storage portion having a predetermined wedge angle between opposing surfaces of the inner member and the outer ring, and a spring storage portion communicating with the rolling body storage portion. In the one-way clutch formed by urging the rolling element stored in the rolling element storage part in the narrow direction of the storage part by the spring member stored in the inner part, the internal member has a non-circular part. part No ablation shape with a diameter parallel to the plane at a position beyond the center of the cylindrical body portion, the above-mentioned rolling element accommodating portions missing the circular portion and the spring housing portion is provided one pair, said rolling element accommodating portion 1 rolling with a diameter that includes the center The structure that contained the body was adopted.
[0009]
The one-way clutch having the above structure is used by connecting one end portion of an inner member to a shaft, and the inner member integral with the shaft rotates relative to the outer ring in a fixed direction, so Locking by biting occurs, and torque is transmitted. Further, due to the rotation in the reverse direction, the rolling element becomes free, and the transmission of torque is interrupted. Since the rolling element storage portion and the spring storage portion are provided in the circular part of the internal member, the size can be significantly reduced as compared with the conventional one.
[0010]
The number of the rolling element storage portions and the spring storage portions (equal to the number of rolling elements) is determined according to the load capacity, but only one set may be provided.
[0011]
Further, a cam surface forming a wedge angle of the rolling element storage portion in the internal member is formed by a notch surface parallel to the diameter direction of the internal member, and the enlarged side of the rolling surface storage portion of the cam surface The structure which provided the spring seat of the said spring accommodating part on both sides of the roller retaining rib can be employ | adopted. According to this configuration, the cam surface is easy to manufacture, and the presence of the roller retaining rib prevents the rolling element from retreating beyond a certain level, so that the spring member is crushed by the rolling element during idling, and during idling. Prevents rolling elements from locking.
[0012]
It is possible to employ a configuration in which the inner member is provided with a connecting portion with a shaft, a radial bearing portion of the outer ring, and a flange that is larger in diameter than the radial bearing and is in contact with the end face of the outer ring. The radial bearing in this case functions to rotate smoothly while keeping the inner member and the outer ring concentric. Further, the flange serves to prevent the internal member from coming off.
[0013]
By providing an outer ring on the outer diameter surface of the outer ring by fitting or by integral molding, a one-way clutch unit comprising a combination of the one-way clutch and the outer ring can be configured. Similarly, a one-way clutch unit comprising a combination of the one-way clutch and the shaft can be configured by connecting the shaft to a connecting portion provided in the internal member.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, this embodiment is a one-way clutch in which a shaft 5 and an outer ring 6 are combined with a one-way clutch composed of an inner member 1, an outer ring 2, a roller 3, and a spring member 4. Indicates a unit.
[0015]
As shown in FIG. 1B and FIG. 2B, the internal member 1 has a non-circular portion 7 having a shape obtained by cutting a cylindrical body in a plane parallel to the diameter at a fixed position. A radial bearing portion 8 composed of a cylindrical portion including an arc surface common to the arc surface is formed at one end portion of the shaft, and a flange 9 having a larger diameter is formed on the outer end surface of the radial bearing portion 8. The cutout circular portion 7 is formed with a cam surface 11 which is a flat surface on one side of the lengthwise roller retaining rib 12 provided on the cut surface and a spring seat 13 which is a concave surface on the other side. . The ratio of the widths a and b (see FIG. 1B) of the cam surface 11 and the spring seat 13 with respect to the roller retaining rib 12 is about 2 to 1 in the illustrated case.
[0016]
The outer ring 2 is fitted and supported rotatably on the arcuate surface of the above-mentioned circular part 7 and the radial bearing part 8. Its outer diameter is equal to the diameter of the shaft 5. Further, the flange 9 is pressed against one end face thereof. A roller accommodating portion 14 is formed by the inner diameter surface of the outer ring 2 and the cam surface 11. The roller storage portion 14 has a narrow side on the side where the cam surface 11 and the inner diameter surface of the outer ring 2 are in contact, and an enlarged side on the roller retaining rib 12 side, and the roller 3 is stored in the roller storage portion 14. An angle α (see FIG. 3A) formed by the tangent drawn to the contact point of the inner diameter surface 3 of the outer ring 2 and the cam surface 11 is referred to as a wedge angle. The wedge angle α is appropriately set in the range of more than 0 degree and not more than 10 degrees.
[0017]
A spring accommodating portion 14 ′ communicating with the roller accommodating portion 14 is formed by the spring seat 13 and the inner diameter surface of the outer ring 2. The spring member 4 housed here is formed by bending a leaf spring. The bent portion is fitted to the spring seat 13, and its free end is pressed against the roller 3. It is biased toward the narrow side of the storage unit 14.
[0018]
The outer ring 6 is a metal cylindrical body that is press-fitted into the outer diameter surface of the outer ring 2 and is integrated with a boss such as a gear in use. When the outer ring 6 is molded from a synthetic resin, there is a disadvantage that creep occurs on the outer ring 2 because of low dimensional accuracy. For this reason, as shown in FIG. 4A, an axial rib 16 is provided on the inner diameter surface of the outer ring 6 to be fitted in the groove 15 provided on the outer diameter surface of the outer ring 2. It is desirable to prevent rotation by fitting. As shown in FIG. 4B, the outer ring 2 and the outer ring 6 may be integrally formed.
[0019]
The shaft 5 has the same outer diameter as the outer ring 2 (see FIG. 1A). Although there are various lengths depending on the application, in the illustrated case, the connecting portion 17 is provided on one end face thereof. As shown in FIG. 2, the connecting portion 17 includes a connecting convex portion 18 having a circular cross section having an arc surface fitted to the inner diameter surface of the outer ring 2, and a circular connecting concave portion 19 having the same circular arc as the connecting convex portion 18. Consists of. The connecting projection 18 has a cross-sectional shape complementary to the surface formed by the cam surface 11, the roller retaining rib 12, and the spring seat 13 formed in the cutout circular portion 7 of the internal member 1. Therefore, a cylindrical part is formed by the connecting convex part 18 and the circular part 7, and a radial bearing that is fitted to the inner diameter surface of the outer ring 2 is formed by the cylindrical part.
[0020]
Moreover, the connection recessed part 19 makes the same oval shape as the cross-sectional shape of the oval part 7 so that the front-end | tip part of the oval part 7 of the internal member 1 can press-fit.
[0021]
As described above, the tip end portion of the cut-out circular portion 7 is fitted to the connecting convex portion 18 and the connecting concave portion 19 so that one end surface of the outer ring 2 is closed, and the roller 3 inside the outer ring 2 is The movement of the spring member 4 in the axial direction is restricted.
[0022]
The one-way clutch unit of the embodiment is as described above, and the outer ring 2 is rotated toward the narrow side of the roller housing portion 14 with respect to the inner member 1 by the relative rotation of the shaft 5 and the outer ring 6. Then (see arrow A in FIG. 1 (b)), the roller 3 moves in that direction and locks by causing biting. Thereby, torque is transmitted from the shaft 5 to the outer ring 6 or in the opposite direction.
[0023]
When the direction of rotation is the opposite direction (see arrow B in FIG. 3 (b)), the roller 3 moves to the enlargement side (from the one-dot chain line to the solid line state in FIG. 3 (b)). It becomes free and torque transmission is cut off. In this case, the roller 3 is prevented from being squeezed by the roller retaining rib 12 since the roller 3 is prevented from retreating beyond a certain level.
[0024]
In the above, the case where the roller 3 is used as the rolling element has been described, but a ball may be used.
[0025]
【The invention's effect】
The one-way clutch and the one-way clutch unit according to the present invention have the following effects.
(1) Since it is composed of an inner member and an outer ring, at least one rolling element and a spring member, the number of parts is small and the cost is low, and it is easy to assemble.
(2) Since the rolling element storage portion and the spring storage portion are provided in the circular part of the internal member connected to one end of the shaft without passing the shaft through the one-way clutch, the size can be reduced by reducing the diameter. Is possible.
(3) When the outer diameter of the outer ring is formed so as to coincide with the outer diameter of the shaft, the one-way clutch can be provided as a one-way clutch unit integrated with the shaft.
[Brief description of the drawings]
1A is a partially omitted cross-sectional view of an embodiment; FIG. 2B is an enlarged cross-sectional view taken along line bb of FIG. 2A; FIG. 2A is a perspective view of the same; 3A is an explanatory view of the wedge angle of the above. FIG. 4B is an explanatory view of the operation of the same. FIG. 4A is a partially exploded perspective view of a modification. FIG. 3B is a partial perspective view of another modification. 5] Cross-sectional view of conventional example [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer ring 3 Roller 4 Spring member 5 Shaft 6 Outer ring 7 Notch circular part 8 Radial bearing part 9 Flange 11 Cam surface 12 Roller stop rib 13 Spring seat 14 Roller accommodating part 14 'Spring accommodating part 15 Groove 16 Rib 17 Connection Part 18 Connection convex part 19 Connection concave part

Claims (4)

An inner member, an outer ring fitted to the inner member so as to be relatively rotatable, a rolling element interposed between the inner member and the outer ring, and a spring member that biases the rolling element in one direction, A rolling element storage portion having a predetermined wedge angle between the surfaces facing the outer ring and a spring storage portion communicating with the rolling body storage portion are provided, and the spring member stored in the spring storage portion is provided in the rolling element storage portion. In the one-way clutch formed by energizing the stored rolling element in the narrow direction of the storage portion,
The internal member has a cut-off circular part, and the cut-off circular part has a shape cut by a plane parallel to the diameter at a position beyond the center of the cylindrical part, and the rolling element storage part and the cut-off circular part are formed in the cut-off circular part. One set of spring accommodating portions is provided, and one rolling element having a diameter including the center is accommodated in the rolling element accommodating portion,
The cam surface forming the wedge angle of the rolling element storage portion in the internal member is formed by a notch surface parallel to the diameter direction of the internal member, and the enlarged side end portion of the rolling element storage portion of the cam surface A spring seat for the spring housing part is provided with a roller retaining rib sandwiched between
The spring member is formed by a plate spring bent in a U-shape, its free end is pressed against the rolling element, the bent portion is fitted to the spring seat, and the other end is pushed against the inner diameter surface of the outer ring. the one-way clutch, characterized in that it was applied. To the internal member, the connecting portion of the shaft, according to claim 1, wherein the radial bearing portions of the outer ring, and a larger diameter than the radial bearing in that a flange which is brought into contact with the outer ring end flush Direction clutch. 3. A one-way clutch unit, wherein an outer ring is provided on an outer ring outer diameter surface of the one-way clutch according to claim 1 by fitting or integral molding. The one-way clutch unit according to claim 3 , wherein a shaft is connected to a connecting portion provided in the internal member.

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