JP3445864B2 - Torque limiter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter used for an apparatus for preventing double feed of paper and a brake device in various office equipment and the like. 2. Description of the Related Art FIG. 2 shows a conventional torque limiter of this type. This torque limiter is rotatably provided with an outer ring 22 having one end closed on the outer side of an inner ring 21 which is prevented from rotating around the shaft 20, and one end of a coil spring 23 for tightening the outer diameter surface of the inner ring 21 is provided on the closed end of the outer ring 22. The other end is engaged with a ring-shaped lid 24 attached to the opening of the outer ring 22, and the contact portion between the inner ring 21 and the coil spring 23 is lubricated by grease sealed inside the outer ring 22. In the torque limiter, when the inner ring 21 is rotated in the direction opposite to the winding direction of the coil spring 23 when viewed from the lid 24 side, the coil spring 23 is tightened and the inner ring 2 is rotated.
1 is increased, and the rotation of the inner race 21 is transmitted to the outer race 22 via the coil spring 23. A load is applied to the outer ring 22 and the coil spring 23
Is tightening the inner ring 21 by the coil spring 23 and the inner ring 2.
1 is smaller than the frictional force acting on the contact portion,
Slip occurs at a contact portion between the first ring 1 and the coil spring 23, and transmission of rotation from the inner ring 21 to the outer ring 22 is interrupted. In the torque limiter, the number of parts is small, the assembly is easy, the manufacturing cost is low, and when the lid 24 is rotated with respect to the outer ring 22, the inner diameter of the coil spring 23 changes, so that the binding force is changed. Has a characteristic that the magnitude of the torque that can be transmitted from the inner race 21 to the outer race 22 can be adjusted. In the above-described conventional torque limiter, when the inner ring 21 rotates and stops, the coil spring 23 changes its diameter. Grease enclosed in the outer ring 22 flows toward the closed end wall 25 of the outer ring 22. For this reason, during use of the torque limiter, the grease easily leaks to the outside along the contact surface between the one end of the inner ring 21 and the closed end wall of the outer ring 22 with the passage of time, and contaminates other parts and paper in the office equipment. There is a risk. An object of the present invention is to prevent oil leakage of a torque limiter using a coil spring. In order to solve the above-mentioned problems, according to the present invention, an outer ring whose one end is closed is provided outside an inner ring which is prevented from rotating with respect to a shaft, and the outer ring is closed. An insertion hole into which one end of the inner ring is inserted is formed in the inner surface of the end wall, and a ring-shaped lid for rotatably supporting the other end of the inner ring is attached to an opening of the outer ring. One end of the coil spring is fastened to the outer ring, the other end is latched to the lid, and a grease sealed inside the outer ring lubricates a contact portion between the inner ring and the coil spring. A first oil reservoir is provided between the bottom surfaces of the insertion holes, and a large-diameter hole for forming a second oil reservoir is formed between one end of the inner surface of the inner ring and the outer surface of the shaft. I have. As described above, the oil sump is formed between one end face of the inner race and the bottom face of the insertion hole and between one end face of the inner diameter face of the inner race and the outer face of the shaft. Grease flowing in the inner diameter direction of the outer ring along the contact surface between the oil reservoir and the insertion hole can be stagnated in each oil sump, and leakage of grease to the outside is prevented by a labyrinth effect generated in the oil sump. An embodiment of the present invention will be described below with reference to FIG. As shown, an outer ring 2 is provided outside the inner ring 1. The outer ring 2 has one end open and the other end closed. An insertion hole 4 is provided on the inner surface of the closed end wall 3, and a shaft insertion hole 5 is provided on the bottom surface of the insertion hole 4. The inner ring 1 has one end inserted into the insertion hole 4 and is rotatably supported. The other end is rotatably supported by a ring-shaped lid 6 attached to the opening of the outer ring 2. I have. Here, the lid 6 is rotatably attached to the outer ring 2 and is prevented from rotating by a frictional force acting on a contact portion with the outer ring 2. The coil spring 7 incorporated between the inner ring 1 and the outer ring 2 has a configuration in which a small-diameter coil portion 7b is connected to an end of a large-diameter coil portion 7a. The diameter surface is tightened. Large-diameter coil portion 7a and small-diameter coil portion 7b
Are provided with bent pieces 8 and 9 at each end. One bent piece 8 is engaged with an engagement hole 10 formed on the inner surface of the lid 6, and the other bent piece 9 is engaged with an engagement hole 11 provided on the inner surface of the closed end wall 3 of the outer ring 2. Has been stopped. Grease is sealed between the inner ring 1 and the outer ring 2, and the grease lubricates a contact portion between the inner ring 1 and the coil spring 7. A shaft 12 is inserted inside the inner ring 1,
A pin 13 provided on the shaft 12 engages a notch 14 formed at the other end of the inner ring 1, and the engagement causes the shaft 12 to
Is stopped. A small diameter shaft portion 15 is provided on one end surface of the inner ring 1, and a first oil sump 16 is provided around the small diameter shaft portion 15 between one end surface of the inner ring 1 and the bottom surface of the insertion hole 4. I have. A large-diameter hole 18 is formed at one end of the inner surface of the inner ring 1 between the outer surfaces of the shaft 12 to form a second oil reservoir 17. The inner ring 1 may be formed of a non-porous material or a porous material such as a sintered metal and impregnated with a lubricating oil. By forming the inner ring 1 from a porous material and impregnating it with lubricating oil, the initial penetration between the inner ring 1 and the small-diameter coil portion 7b can be improved by the lubricating oil oozing on the surface of the inner ring 1. The torque limiter shown in the embodiment has the above-mentioned structure, and the operation of the torque limiter is the same as that of the above-described torque limiter of FIG. In the torque limiter shown in the embodiment,
A first oil reservoir 16 is provided between one end surface of the inner ring 1 and the bottom surface of the insertion hole 4.
And the second oil reservoir 17 is provided between one end of the inner surface of the inner ring 1 and the outer surface of the shaft 12, so that the second oil sump 17 is gathered on the closed end wall side of the outer ring 2 by the screw pumping action of the coil spring 7. Grease is transmitted along the contact surface between the inner ring 1 and the insertion hole 4 and the outer ring 2
When the grease flows in the inner diameter direction of the
6 enters and stagnates. When the grease in the first oil sump 16 flows along the contact surface between the inner ring 1 and the insertion hole 4 and flows in the inner diameter direction of the insertion hole 4, the grease enters the second oil sump 17 and stagnates. At this time, a labyrinth effect occurs in the first oil sump 16 and the second oil sump 17, and the labyrinth effect causes invasion generated between the contact surface between one end of the inner ring 1 and the closed end wall 3 of the outer ring 2. It is possible to prevent the grease from leaking to the outside due to reduced pressure. As described above, in the torque limiter according to the present invention, the first oil reservoir is provided between the one end face of the inner ring and the bottom face of the insertion hole formed in the closed end wall of the outer ring, and the inner ring is provided. By forming a second oil sump between one end of the inner diameter surface of the inner ring and the shaft, grease flowing in the inner diameter direction of the outer ring through the contact surface between the one end of the inner ring and the closed end wall of the outer ring is formed by each oil sump. The grease can be stagnated, and external leakage of grease can be prevented by a labyrinth effect generated in each oil reservoir. Also, by providing two oil sumps,
The grease can be prevented from leaking in two stages, and the grease can be more effectively prevented from leaking as compared with the case where the grease is prevented from leaking by one oil reservoir.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an embodiment of a torque limiter according to the present invention. FIG. 2 is a cross-sectional view showing a conventional torque limiter. 4 insertion hole 6 lid 7 coil spring 12 shaft 16 first oil sump 17 second oil sump 18 large diameter hole

Claims (1)

(57) [Claim 1] An outer ring whose one end is closed is provided outside the inner ring which is prevented from rotating with respect to the shaft, and one end of the inner ring is inserted into the inner surface of the closed end wall of the outer ring. A ring-shaped lid that rotatably supports the other end of the inner ring is attached to the opening of the outer ring, and one end of a coil spring that tightens the outer diameter surface of the inner ring is attached to the outer ring. A first oil reservoir between one end surface of the inner ring and a bottom surface of the insertion hole, wherein the first oil sump is fixed to the lid body and lubricates a contact portion between the inner ring and the coil spring by grease sealed inside the outer ring. And a large diameter hole for forming a second oil reservoir is formed between one end of the inner surface of the inner ring and the outer surface of the shaft.