JP4240384B2 - Brake mechanism - Google Patents

Description

  The present invention relates to a brake mechanism capable of restraining rotational movement around an axis of a shaft and linear movement in the axial direction by utilizing elastic deformation of an annular body such as a metal ring.

  2. Description of the Related Art Conventionally, as a brake mechanism capable of restraining rotational movement around the axis of a shaft, a disk brake mechanism that presses a disk board mounted coaxially with a shaft with brake pads from both sides is known. This disc brake mechanism includes a hydraulic type that presses the brake pad against the disc board by hydraulic pressure, and an electromagnetic type that presses the brake pad against the disc board using a solenoid, both of which press against the brake pad. When released, the brake force by the brake pad is released by the spring force of the return spring.

  Since the brake mechanism is often incorporated in a complicated mechanism such as a machine tool, it is desirable that the brake mechanism be small. However, since the disc brake mechanism requires a separate hydraulic mechanism or solenoid for pressing the pad against the disc board, there is a problem that the device becomes large when they are combined.

  In addition, depending on the type of use, the brake mechanism is required to hold the shaft in a locked state and stop its rotational movement for a long time. To that end, the hydraulic mechanism or solenoid is operated for a long time. It must be kept in a letting state. For this reason, there is a problem that the load on the hydraulic mechanism or the solenoid is large and the power consumption is large.

  Further, in the configuration such as the disc brake mechanism, the rotational motion around the axis of the shaft can be restrained, but the linear motion in the axial direction cannot be restrained.

  An object of the present invention is to propose a brake mechanism that can solve the above-mentioned problems.

In order to solve the above problems, the brake mechanism of the present invention is configured to be able to restrain or restrain the rotational motion and linear motion of the shaft with a simple configuration by utilizing elastic deformation of the annular body. That is, the brake mechanism of the present invention is
A perfectly circular ring that is elastically deformable in the radial direction;
A plurality of inner protrusions protruding radially inward from the inner peripheral surface of the annular body;
A plurality of outer protrusions projecting radially outward from the outer peripheral surface of the annular body;
When the outer protrusion is pushed inward in the radial direction, the inner protrusion and the outer protrusion are displaced from each other along the circumferential direction of the annular body so that the inner protrusion moves outward in the radial direction. Formed,
The diameter of the inscribed circle inscribed in the front end surface of the inner protrusion is set to be smaller than the outer diameter of the constrained shaft.

  In the brake mechanism having this configuration, the shaft can be passed through the annular body by pushing the outer protrusion inward and elastically deforming the annular body to spread the inner protrusion. When the force applied to the outer protrusion is released after passing through the shaft, the inner protrusion is brought into pressure contact with the outer peripheral surface of the shaft by the elastic restoring force of the annular body, and the braking state of the shaft is formed. In order to release the braking force acting on the shaft, in this state, if the outer protrusion of the annular body is pushed inward, the annular body is elastically deformed and the inner protrusion is expanded, acting on the shaft. The braking force is released and the shaft can be rotated and linearly moved.

  Here, in order to apply a braking force evenly from each part of the outer peripheral surface to the shaft, each outer protrusion is positioned between each inner protrusion when viewed along the circumferential direction of the annular body. Thus, the inner and outer protrusions may be formed at equiangular intervals.

  Further, in order to apply a large braking force to the shaft, it is only necessary to secure the contact area with the outer peripheral surface of the shaft by using the tip surface of each inner protrusion as an arc surface.

In the brake mechanism of the present invention, the braking force can be applied to the shaft and the braking force can be released by utilizing the elastic deformation of the perfect circular annular body. Therefore, since no external power is required to stop the movement of the shaft, the brake mechanism can be made compact and compact.

  Further, in order to release the braking force, it is only necessary to slightly deflect the annular body in the radial direction by pushing in the outer protrusion of the annular body. Therefore, as a mechanism for bending the annular body, a mechanism with a small displacement such as a laminated piezoelectric element actuator can be used instead of a mechanism with a large displacement such as a hydraulic mechanism or a solenoid. Also in this respect, according to the present invention, the brake mechanism can be configured to be small and compact.

  Furthermore, since it has a simple structure in which the outer protrusion and the inner protrusion are formed on an elastically deformable annular body, it can operate reliably and can be manufactured at low cost.

  Hereinafter, an example of a brake mechanism to which the present invention is applied will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a state where an annular body, which is a feature of a brake mechanism to which the present invention is applied, is attached to a shaft. 2 (a) and 2 (b) are a perspective view and a front view of the annular body of FIG. The brake mechanism 1 of the present example is capable of restraining the rotational movement around the axis of the shaft S and the linear movement in the axial direction, and is used to elastically deform the annular body 2 and the annular body 2 in the radial direction. It has a pressing mechanism and a holding mechanism that holds the annular body 2 in a fixed position in a state where it can be elastically deformed in the radial direction.

  The annular body 2 can be elastically deformed in the radial direction, and is formed of a metal having a high fatigue strength so as not to be fatigued even when repeatedly elastically deformed. The annular body 2 includes a pair of inner protrusions 3a and 3b protruding radially inward from the circular inner peripheral surface 21 and a pair of outer protrusions 4a and 4b protruding radially outward from the circular outer peripheral surface 22. Have. Here, the inner protrusions 3a and 3b are formed at point-symmetrical positions, and the outer protrusions 4a and 4b are also formed at point-symmetrical positions. The outer protrusions 4a and 4b are formed at angular positions shifted by 90 degrees in the circumferential direction with respect to the inner protrusions 3a and 3b.

  The front end surfaces 31a and 31b of the inner projections 3a and 3b have an arc shape located on a concentric circle centered on the center of the annular body 2, and the diameter of the concentric circle is the outer diameter of the shaft S inserted coaxially therewith. Is set to a slightly smaller dimension. For this reason, in a state where the shaft S is inserted into the annular body 2, the inner protrusions 3 a and 3 b push the shaft S from both sides toward the central axis S 1 by the elastic force of the annular body 2. It is desirable to attach a lining material having a large friction coefficient such as bronze or cast iron to the tip surfaces 31a and 31b of the inner protrusions pressed against the outer peripheral surface of the shaft S.

  The front end surfaces 41 a and 41 b of the pair of outer protrusions 4 a and 4 b projecting outward in the radial direction from the outer peripheral surface 22 of the annular body 2 are flat surfaces orthogonal to the radial line of the annular body 2. When these front end surfaces are pressed from both sides by a pressing mechanism including a screw-type actuator, a laminated piezoelectric element actuator, etc., the annular body 2 is bent into an elliptical shape, and the inner protrusions 3a and 3b are pushed and spread. Instead of pushing the outer protrusions 4a and 4b from both sides by the pressing mechanism, one side may be fixed by the holding mechanism and pushed by the pressing mechanism from the other side.

  The operation of the brake mechanism 1 configured as described above will be described. FIGS. 3A and 3B are explanatory views showing a state where the annular body 2 of the brake mechanism 1 of this example restrains the shaft S, and the annular body 2 of the brake mechanism 1 releases the restraint of the shaft S. It is explanatory drawing which shows the state which carried out. As shown in FIG. 3A, when no external force is applied to the outer protrusions 4a and 4b, the inner protrusions 3a and 3b push the shaft S from both sides toward the center axis S1 by the elastic force of the annular body 2. The tip surfaces 31a and 31b of the inner protrusions 3a and 3b press the outer peripheral surface of the shaft S. Therefore, since the braking force due to the elastic restoring force of the annular body 2 is applied to the shaft S from the pair of inner protrusions 3a and 3b, the shaft S is in a brake lock state in which the rotational motion around the axis and the linear motion in the axial direction are restrained. Retained.

  When force F is applied to the front end surfaces 41a and 41b of the outer protrusions 4a and 4b of the annular body 2 in the brake lock state by a pressing mechanism such as a laminated piezoelectric element actuator, the annular body 2 is elastically deformed and the outer protrusions The portions 4a and 4b bend inward, the portions of the inner protrusions 3a and 3b spread outward, and deformed into an oval shape as a whole. As a result, as shown in FIG. 3B, the tip surfaces 31a and 31b of the inner protrusions 3a and 3b are separated from the outer peripheral surface of the shaft S, the braking force against the shaft S is released, and the shaft S is rotated around the axis. It switches to the state which can perform the rotational motion and the linear motion in the axial direction.

  As described above, in the brake mechanism 1 of this example, the braking force can be released by applying a braking force to the shaft S by the elastic restoring force of the annular body 2 and elastically deforming the annular body 2 by the pressing mechanism. Therefore, no external power is required to stop the movement of the shaft S, which is effective when it is desired to stop the movement of the shaft S for a long time. Also, the brake force can be released by simply bending the annular body 2 slightly in the radial direction. Therefore, the pressing mechanism is not a large displacement such as a hydraulic mechanism or a solenoid, and the displacement of the laminated piezoelectric element actuator is very small. Can be used. Therefore, a compact and compact brake mechanism can be realized.

  In particular, the laminated piezoelectric element actuator can generate a large force even with a small size, and is therefore suitable for use as a pressing mechanism for elastically deforming an annular body. In addition, when a laminated piezoelectric element actuator is used, the pressure applied to the outer protrusions 4a and 4b can be easily increased or decreased by controlling the voltage applied thereto, so that the brake force applied to the shaft S can be adjusted steplessly. There is also an advantage of being able to do it.

  Furthermore, since the brake mechanism 1 of this example has a simple structure in which the protrusions are formed on the annular body 2, it can operate reliably, can be manufactured at low cost, and requires a small installation space.

  Furthermore, since the inner protrusion and the outer protrusion are arranged at equal angular intervals and each inner protrusion is positioned in the middle of each outer protrusion, the displacement amount of each inner protrusion can be made equal. Therefore, since the shaft can be pressed from both sides with an equal force, the movement of the shaft can be reliably restrained.

(Another example of an annular body)
FIGS. 4A and 4B are a perspective view and a front view showing another example of the annular body 2. The annular body 2A of this example has a perfect circle shape, and the inner protrusions 3c, 3d, and 3e are formed at three positions at equal angular intervals on the circular inner peripheral surface 21, and the circular outer peripheral surface 22 is also equiangularly spaced. The outer projections 4c, 4d, and 4e are formed at three locations. The inner protrusions 3c, 3d, and 3e and the outer protrusions 4c, 4d, and 4e are formed at positions shifted by 60 degrees in the circumferential direction. The front end surfaces 31c, 31d, 31e of the inner protrusions 3a, 3d, 3e are arcuate surfaces located on concentric circles, and the diameter of the concentric circles is set to be slightly smaller than the outer diameter of the shaft S. The front end surfaces 41c, 41d, 41e of the outer protrusions 4c, 4d, 4e are flat surfaces.

  When the annular body 2A having this shape is used, each of the outer protrusions 4c, 4d, and 4e may be pressed by a pressing mechanism, one outer protrusion is fixed by a holding mechanism, and the remaining two outer protrusions are fixed. You may press by a press mechanism. In any case, the annular body 2A bends in a triangular shape, and the braking force by the inner protrusions 3c, 3d, and 3e can be released.

  Even when the annular body 2 </ b> A of this example is used, the same effect as that obtained when the above-described annular body 2 is used can be obtained. Moreover, in this example, since the shaft S is pushed from three places at equal angular intervals, the shaft S can be locked in a positioned state. If the number of the inner protrusions arranged at equal angular intervals is increased, the shaft can be pressed evenly from each part of the outer periphery.

  In addition, in the annular body in each of the above examples, the tip surface of the inner projection for pressing the shaft is an arc surface, but other shapes can be used. In any case, the diameter of the inscribed circle inscribed in the tip surface may be set to be slightly smaller than the outer diameter of the shaft.

It is a perspective view which shows the state which attached the annular body of the brake mechanism to which this invention was applied to the shaft. (A) And (b) is the perspective view and front view of the annular body of FIG. (A) And (b) is explanatory drawing which shows the state which the annular body has restrained the shaft, and explanatory drawing which shows the state which cancelled | released restraint of the shaft. (A) And (b) is the perspective view and front view which show another example of a cyclic | annular body.

Explanation of symbols

1 Brake mechanism
2, 2A ring
Inner circumferential surface of 21 annular body
22 Outer peripheral surfaces 3a to 3e Inner protrusions 31a to 31 e Inner protrusion tip surfaces 4a to 4 e Outer protrusions 41a to 41 e Outer protrusion tip surfaces S Shaft

Claims (3)

A perfectly circular ring that is elastically deformable in the radial direction;
A plurality of inner protrusions protruding radially inward from the inner peripheral surface of the annular body;
A plurality of outer protrusions projecting radially outward from the outer peripheral surface of the annular body;
When the outer protrusion is pushed inward in the radial direction, the inner protrusion and the outer protrusion are displaced from each other along the circumferential direction of the annular body so that the inner protrusion moves outward in the radial direction. Formed,
A brake mechanism using elastic deformation of an annular body in which a diameter of an inscribed circle inscribed in a tip surface of the inner protrusion is set to be smaller than an outer diameter of a shaft to be constrained. In claim 1,
A brake mechanism in which the inner and outer protrusions are formed at equal angular intervals so that the outer protrusions are positioned between the inner protrusions when viewed along the circumferential direction of the annular body. In claim 1 or 2,
A brake mechanism in which the tip surface of each inner protrusion is an arc surface.

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