JPH02245524A - Over running clutch - Google Patents

Abstract

PURPOSE:To prevent any damage to a member by constructing the title clutch in such as way that a hollow roller bit'es a clutch outer and a clutch inner firstly and then a solid roller bites them. CONSTITUTION:The outer diameter of a solid roller 3 is formed slightly smaller than the outer diameter of a hollow roller 4. A clutch outer 1 is rotated in an arrow direction under a state that load torque is applied to a clutch inner 2 and load is applied to the roller 4 according to load torque to be crushed and deformed thereby. Deforming quantity reaches certain quantity and the roller 3 touches a cam curve. Supposed that a relative rotary angle between the clutch inner 2 and the clutch outer 1 until now is beta. A plurality of circumferential grooves 6 provided at a retainer 5 and a plurality of pins 7 provided at the clutch outer 1 are connected with each other via an elastic body 8 and are movable in a rotary direction relatively. When the angle beta of the roller 3 becomes angle gamma, the pin 7 makes contact with the end of the circumferential groove 5, limitation is given to a relative rotational angle, and load torque applied thereto over the limitation makes slippage be generated at the roller to prevent any damage to a member.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an overrunning clutch that has low rigidity at the initial stage of biting, and is suitable for starters.

[Conventional technology]

The conventional overrunning clutch is
As described in Japanese Patent No. 3695, the clutch has two wedge angles, one of which is larger than the friction angle, and the rollers slide to limit the transmitted torque and reduce abnormal impact torque generated in the clutch. It had a structure that absorbed it.

The relationship between the transmission torque and the relative rotational angle between the clutch outer and the clutch inner of the clutch, that is, the spring stiffness in the rotational direction of the clutch, is a curve that smoothly increases, then reaches an upper limit value, and remains constant beyond that.

[Problem to be solved by the invention]

Although the above-mentioned conventional technology suppresses the upper limit value of the load torque, it is not possible to change the slope (spring stiffness) up to the upper limit value.

As for the ability to absorb impact torque, not only the upper limit value but also the intermediate progress is important. In other words, at the initial stage, the spring stiffness is made soft (lower) to smoothly absorb the impact, and then gradually stiffened to receive the impact firmly.
Effective in preventing damage to components.

The purpose of the present invention is to set the spring stiffness of the clutch at a low level at first, and then gradually increase it until it reaches the upper limit, thereby reducing the impact torque from the driven side and preventing damage to the members.

Another object of the present invention is to simplify the cam curve of the clutch outer to reduce costs.

Conventionally, in order to suppress the upper limit of load torque, a protrusion toward the center was provided for each cam curve of the clutch outer to act as a stopper for the roller, which had the disadvantage of complicating the cam curve of the clutch outer and increasing costs. Ta.

[Means to solve the problem]

In order to achieve the above object, the pot-forming ability of the roller is varied, and the spring stiffness in the process from roller biting to the upper limit value is varied.

That is, the clutch is configured such that a hollow roller is first inserted into a clutch outer and a clutch inner, and then a solid roller is inserted.

For this purpose, the cam curve of the clutch outer is formed with a plurality of identical curves at equal intervals around the circumference corresponding to the number of rollers, and the rollers are fitted into the retainer at equal intervals around the circumference.

Make the outer diameter of the hollow roller slightly larger than the outer diameter of the solid roller.

Alternatively, the same effect can be obtained by making the outer diameter of the hollow roller equal to the outer diameter of the solid roller and forming the cam curve that engages the solid roller with a slight shift.

Next, to achieve the second objective, the cam curve of the clutch outer is simplified.

That is, the cam curve portion that the roller engages with is one type of circular arc, and the ends of the cam curve are connected by small circular arcs.

As shown in FIG. 10, the clutch outer 1 has a cam curve with a radius of RA, an arc with a radius of R8 at the end of the cam curve, and a cam curve with a radius of R8.
4 and a circular arc with a radius R2 connecting the cam curves, and a plurality of pins 7 are fixed to the side surface.

[Effect]

The outer diameter of half of the plurality of rollers in the overrunning clutch is made slightly smaller than that of the remaining rollers, and the load torque is initially borne by half of the rollers, thereby lowering the spring stiffness in the rotational direction of the clutch. At this time, in order to further reduce the spring stiffness, half of the rollers that come into contact initially are hollow rollers. After the hollow roller is deformed by an amount equal to the outer diameter of the solid roller, the spring stiffness rapidly increases because the hollow roller and the solid roller bear the load torque. However, the spring stiffness is lower than in the conventional case where all rollers are solid.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Solid rollers 3 and hollow rollers 4 are placed alternately in a wedge-shaped space formed by a clutch outer 1 and a clutch inner 2. The rollers are arranged at equal intervals around the circumference of the retainer 5, and the retainer is inserted into a wedge-shaped space. The retainer has circumferential grooves 6 at a plurality of locations on its circumference, which are aligned with the same number of pins 7 fixed to the side surface of the clutch outer 1, and are arranged concentrically with the clutch outer. Next, the operation of the present invention will be explained using FIG. The hollow roller 4 shown by the solid line is in contact with the cam curve of the clutch outer 1, but since the outer diameter of the solid roller 3 shown by the solid line is slightly smaller than the outer diameter of the hollow roller 4, there is a gap between the hollow roller 4 and the cam curve. There is a gap. When the clutch outer 1 is rotated in the direction of the arrow with a load torque acting on the clutch inner 2, a load (W) is applied to the hollow roller 4 according to the load torque, causing it to be crushed and deformed.

When the amount of deformation reaches a certain value, the solid roller 3' comes into contact with the cam curve (in the figure, the roller moves in the opposite direction of the arrow with respect to the clutch outer and is at the position indicated by the broken line). Let β be the relative rotation angle between the clutch outer 1 and the clutch outer 1.

A plurality of circumferential grooves 6 (same number as the number of rollers in the figure) disposed on the retainer 5 and a plurality of pins disposed on the clutch outer 1 are joined via an elastic body 8 and mutually rotate in the rotation direction. It is movable. Although FIG. 3 shows an example of a compression coil spring as the elastic body 8.

The rubber 8' etc. (FIG. 4) also have a similar effect.

Therefore, the hollow rollers 4 arranged at equal intervals on the circumference are in contact with the cam curve even when no load is applied, and play is eliminated.

Relative rotation angle β between clutch outer 1 and clutch inner 2
When the load torque further increases from the state where the solid roller 3' is in contact with the cam curve, the relative rotation angle increases, and when the angle reaches γ, the pin 7 comes into contact with the end of the circumferential groove 5, and the relative rotation angle increases. Limits the rotation angle (limits the amount of roller bite).

If a load torque greater than this is applied, slippage occurs in the a-ra, the torque is absorbed, and damage to the member can be prevented.

Here, the rotational direction spring stiffness of the clutch will be explained using FIG.

The transmission torque of the conventional clutch relative to the relative rotation angle increases rapidly from the initial stage of the roller biting (double-dotted line), and the impact torque is not absorbed sufficiently, sometimes resulting in damage to one member. In this invention, by making half of the rollers hollow, the spring stiffness curve, which is the sum of the half of the hollow rollers, rises extremely gently from zero, and the angle γ
becomes a constant value (solid line), and for the remaining half of the solid rollers, the curve rises with a delay of an angle β, and the spring stiffness curve that is the sum of the half of the solid rollers is represented by a chain line. Therefore, the broken line obtained by adding the solid line and the dashed-dotted line becomes the spring stiffness curve of the present invention, and it is possible to create a period of extremely low stiffness at the initial stage of biting (from O to β).

Next, the outer radius rl and inner radius rl of the hollow roller.

FIG. 6 shows the relationship between the outer radius r8 of the solid roller.

This will be explained using FIG.

FIG. 6 shows that the hollow roller 4 is connected to the clutch outer 1. The solid roller 3, which is in contact with the clutch inner 2 and located in the adjacent cam curved portion, is in contact with the clutch outer 1. A state in which there is a gap between the clutch inner 2 and the clutch inner 2 is shown.

FIG. 7 shows a state when the relative rotation angle between the clutch outer and the clutch inner becomes β, and a load W acts on the hollow hole 4', resulting in a deformation amount δ in the load direction. At this time, the solid roller 3' moves to the clutch outer 1. It comes into contact with the clutch inner 2 (load starts to be applied).

Therefore, the amount of deformation δ of the solid roller 3 is 2 (rl−r8
) is equal to

The shape of the hollow roller shown in FIGS. 8 and 9 is approximately expressed by equation (1).

Here, E: Modulus of longitudinal elasticity = 21,000 kg/m"Ω Engineering: Moment of inertia of area = H11 Here, in order to lower the stiffness of the hollow roller, it is made thin, and r
When t/rn=n, equation (3) becomes equation (4).

If the relationship between the Hertzian stress (σ) and the load (W) applied to the solid roller is R) r a , then equation (4) can be substituted into equation (5) to obtain equation (6).

If the designed Hertzian stress (σ) is 200 kg/cabinet, the formula (7) is obtained.

...(2) E consideration (rz-r3 doors ...(3) On the other hand, from Figures 6 and 7, approximately (8) formula % formula % Equation (9) is obtained from equations (7) and (8).

As an example, the wedge angle (α) is 6s, β determines the area of low spring stiffness and is 8°, and rδ/R is 0.
Set it to 2. Substituting each into equation (9) yields n=rz/rL=0.81.

Substituting this into equation (7), rz -rs= 0.075 r8. 8ra/rr=
It becomes 0.93.

As another example, when α=6'''β±8'' ra/R-0,25, n=:rz/rt=0.80 rs/ri=0.9
It becomes 4.

Therefore, within the practical range, rz/rt is approximately 0.8 and r2/r1 is approximately 0.9.

(Effects of the Invention) According to the present invention, the spring stiffness in the rotational direction of the overrunning clutch becomes as shown in FIG. Since the spring stiffness gradually increases after the impact torque is received, it is possible to firmly receive the impact torque and prevent damage to the member.

Further, since the upper limit value of the load torque can be limited by the circumferential groove of the retainer and the pin of the clutch outer, it is further useful to prevent damage to the members.

Furthermore, since the cam curve of the clutch outer is formed by one type of circular arc, the 11-piece construction is easy and inexpensive.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an overrunning clutch according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is a partially enlarged view of Fig. 1, and Fig. 4 is a cross-sectional view of an overrunning clutch according to an embodiment of the present invention. 5 is a spring stiffness characteristic diagram in the rotational direction of the overrunning clutch of the present invention, FIGS. 6 and 7 are operation explanatory diagrams, and FIG. 8 is a sectional view of the hollow roller. Figure 9 is a cross-sectional view of Figure 8, Figure 10 is a partially enlarged view of the clutch outer, and Figure 11 is a cross-sectional view of the clutch outer.
The figure is a cross-sectional view of a conventional overrunning clutch.
FIG. 2 is a sectional view taken along line A--A in FIG. 11. 1...Clutch outer, 2...Clutch inner, 3
... solid roller, 4 ... hollow roller, 5 ... retainer, 6 ... circumferential groove, 7 ... pin, 8 ... elastic body.

Claims (1)

[Claims] 1. A cylindrical clutch outer having a tapered cam surface on its inner circumferential surface, a clutch inner forming a wedge-shaped space between the clutch outer and the inner circumferential surface, and a clutch inner forming a wedge-shaped space within the wedge-shaped space. and a roller mounted so as to be movable in the circumferential direction, and transmits power from the clutch outer to the clutch inner, wherein the clutch outer has an even number of cam curves, and the number of rollers is an even number, and half of the rollers are an even number. are hollow rollers, and their outer diameters are larger than the outer diameters of the remaining half of the solid rollers, and the hollow rollers and the solid rollers are arranged alternately. . 2. An overrunning clutch according to claim 1, wherein the hollow roller has an inner diameter smaller than an outer diameter of the solid roller. 3. In the overrunning clutch according to claim 1, the outer radius of the hollow roller is r_1 and the inner radius is r_2.
, when the outer radius of the solid roller is r_3, r_2/r_
1 is approximately 0.8, and r_3/r_1 is approximately 0.8.
An overrunning clutch characterized by a 9. 4. The overrunning clutch according to claim 1, wherein the rollers are supported by being inserted into grooves carved on the outer peripheral surface of the retainer, and the cam curves of the clutch outer are also formed at equal intervals on the circumference. overrunning clutch. 5. In the overrunning clutch according to claim 1, relative rotation is enabled between the retainer and the clutch outer via an elastic body, and the hollow roller contacts the cam curve and the solid roller does not contact the cam curve when no load is applied. An overrunning clutch characterized by being arranged in the following manner. 6. The overrunning clutch according to claim 1, wherein the elastic body is a compression coil spring. 7. The overrunning clutch according to claim 1, wherein the elastic body is rubber. 8. In the overrunning clutch according to claim 1, the circumferential groove of the retainer and the pin fixed to the side surface of the clutch outer limit the relative rotation angle between the two, thereby limiting the amount of bite of the roller with respect to the cam curve of the clutch outer. An overrunning clutch featuring 9. In the overrunning clutch according to claim 1, the portion of the cam curve of the clutch outer that engages with the roller is one type of circular arc (radius R_1), and the ends of the cam curve are small circular arcs (radii R_3, R_4). An overrunning clutch characterized by its shape.