JPH0643322U - Adjustment screw with torque limit - Google Patents

Abstract

(57) [Summary] [Purpose] The adjustment work is simple and can be performed without requiring any skill, and there is no damage to the screw due to excessive turning of the bolt, or damage or breakage of members related to the screw. To prevent. [Structure] Shaft 1 having a threaded portion 1a formed at the bottom thereof
And a disk-shaped rack plate 2 fitted to a substantially middle portion of the shaft, in which a plurality of rack teeth 2b are formed in a ring shape,
The rack teeth 3b that mesh with the rack teeth of the rack plate in one direction are formed, and the cam plate 3 is rotatably fitted and inserted into the shaft, and the cam plate is fitted and fixed to the shaft. And a spring 4 which is housed in the cap and applies a pressing force to the rack plate against the cam plate.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an adjusting screw in which, when tightening a screw, when the tightening force exceeds a constant torque value, the screw is idled so that the tightening torque of the screw becomes constant. It is used in the adjustment part.

[0002]

[Prior art]

 Conventionally, in order to adjust the looseness of the tension of the belt of the power steering as described above, it is general to adjust the adjusting bolt by rotating the adjusting bolt with a spanner. As a method of adjusting the tension gauge, the tension gauge is hooked on the fan belt, and the adjusting bolt is tightened or loosened so that the tension gauge has a constant value.

[0003]

[Problems to be solved by the device]

 By the way, in the adjustment method described above, the adjusting bolt is tightened and loosened while using the tension gauge, which requires complicated adjustments and requires skill, and the tension gauge may come into contact with something other than the belt. If the tension gauge is not in contact with the belt at a right angle, the value of the tension gauge will change and the torque value will change.

The present invention is intended to solve the above-mentioned problems, and an object thereof is to prevent the screw from idling and tightening the screw any more when a certain amount of torque value is applied. This eliminates the need for a tension gauge as in the past, and adjustment work is easy, and adjustments can be made without requiring skill, and screw damage due to over-twisting and damage to the belt due to excessive tension are prevented. There is a torque limit adjustment screw that can be provided.

[0005]

[Means for Solving the Problems]

 The adjusting screw with a torque limit of the present invention achieves the above-mentioned object, and is fitted to a shaft having a screw portion formed at a lower portion thereof and an intermediate portion of the shaft having a plurality of rack teeth formed in a ring shape. Disk-shaped rack plate, rack teeth that mesh with the rack teeth of the rack plate in one direction are formed, and a cam plate rotatably fitted to the shaft and the cam plate are fitted. A cap fixed to the shaft with a screw, and a spring housed in the cap for applying a pressing force to the rack plate with respect to the cam plate are provided.

[0006]

【Example】

 Hereinafter, an embodiment of an adjusting screw with a torque limit according to the present invention will be described with reference to the drawings. Reference numeral 1 is a shaft having a threaded portion 1a formed in the lower portion, and a screw hole 1b is formed in the upper surface thereof. Reference numeral 2 is a disk rack made of synthetic resin in which the shaft 1 is integrally formed by an insert, and a ring-shaped fitting wall 2a is formed on the upper surface. Further, one side is an upright surface on the inner peripheral portion of the fitting wall 2a, and a plurality of rack teeth (4 teeth in the embodiment) 2b inclined from the upright surface in the circumferential direction. Has been formed.

Reference numeral 3 denotes a cam plate made of synthetic resin having a hole 3a rotatably fitted in the shaft 1 and formed at the center thereof, and a cam tooth 3b which meshes with the rack tooth 2b is integrally formed on the lower surface thereof. Has been formed. Further, a plurality of (four in the embodiment) protrusions 3c are formed on the outer peripheral surface in the height direction, and an upstanding wall 3d for receiving a spring 4 described later is formed on the upper surface.

Reference numeral 4 denotes a spring having a size such that the lower end is housed inside the standing wall 3d of the cam plate 3, and 5 is a cap made of synthetic resin having an outer peripheral surface with an uneven slip stopper 5a. A vertical groove 5b is formed on the inner peripheral surface to guide the ridge 3c of the cam plate 3 so as to be movable only in the vertical direction. Further, a recess 5c having a screw insertion hole for the screw 6 screwed into the screw hole 1b at the upper end of the shaft 1 is formed on the upper surface.

When assembling the adjustment screw with the torque limit, the cam plate 3 is oriented so that the shaft 1 is engaged with the rack teeth 2b on the upper surface of the rack plate 2 into which the shaft 1 is inserted. Insert the shaft 1 into the hole 3a so that 3b faces downward. Next, the lower end of the spring 4 is positioned inside the standing wall 3d of the cam plate 3, the shaft 1 is inserted, and then the cap 5 is put on the upper surface of the rack plate 2 so as to cover the spring 4.

At this time, the vertical groove 5b of the cap 5 is covered with the protrusion 3c of the cam plate 3 so as to correspond thereto. Then, after inserting the washer 7 into the recess 5c of the cap 5, the screw 6 is inserted and screwed and fixed in the screw hole 1b of the shaft 1. Accordingly, when the cap 5 is rotated, the cam plate 3 is integrally rotated by fitting the vertical groove 5b and the protrusion 3c.

In the adjusting screw with a torque limit configured as described above, when the cap 1 is rotated counterclockwise in the drawing, the vertical end surfaces of the rack teeth 3b of the cam plate 3 and the rack teeth 2b of the rack plate 2 are changed. And the rack plate 2 rotates integrally. Therefore, the shaft 1 fixed to the rack plate 2 also rotates integrally in the counterclockwise direction. The counterclockwise rotation direction is a direction for loosening the tightened screw portion 1a.

Next, when the screw portion 1a is rotated in the loosening direction (clockwise in the drawing), the rack teeth 3b of the cam plate 3 are pressed against the rack teeth 2b of the rack plate 2 by the spring 4, In the case of a reaction force in the reverse rotation direction from the screw portion 1a, which is weaker than the spring force of the spring 4, the rack plate 2 rotates due to the frictional resistance between the rack teeth 3b and the rack teeth 2b, overcoming this reaction force. The shaft 1 also rotates in the same direction and tightens.

However, as tightening progresses, the reaction force in the reverse rotation direction from the screw portion 1a becomes stronger, and finally the reaction force becomes larger than the pressing force by the spring force of the spring 4 and the frictional resistance between the rack teeth. Become. Then, the rack teeth 3b of the cam plate 3, which can move up and down along the vertical groove of the cap 5, slides on the slope of the rack teeth 2b against the spring force of the spring 4. Starts idling with cap 5. Therefore, the rack plate 2 stops rotating, and no unreasonable rotational force acts on the shaft 1 which is integrated with the rack plate 2 to crush the screw thread of the screw portion 1a or to overtighten the belt related to the screw. There is no chance that it will break.

[0014]

[Effect of device]

 As described above, according to the present invention, in the loosening direction of the screw portion, the rack teeth of the cam plate and the rack teeth of the rack plate are firmly meshed with each other and do not slip. Work can be done easily and reliably. On the other hand, with respect to the tightening direction of the screw part, when the reaction force of the screw part becomes stronger than the spring force of the spring, the rack teeth of the cam plate slide against the rack teeth of the rack plate and rotate freely. become.

Therefore, the screw can be tightened under a constant torque, and the screw thread can be prevented from being damaged due to the tightening of the screw. In particular, when the screw is used as an adjusting bolt of a rotary belt for automobiles. The advantages of the present invention are that the tension of the belt can be easily and securely performed without requiring skill, and the belt can be prevented from breaking due to excessive tension.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of an adjusting screw with a torque limit according to the present invention.

FIG. 2 is a cross-sectional view of the above assembled state.

[Explanation of symbols]

 1 Shaft 1a Screw part 2 Rack plate 2b Rack tooth 3 Cam plate 3b Rack tooth 4 Spring 5 Cap

Claims (1)

[Scope of utility model registration request] 1. A shaft having a threaded portion formed in a lower portion,
It has a disk part in which a plurality of rack teeth are formed in a ring shape,
A rack plate fitted to a substantially middle portion of the shaft, and a cam plate formed with rack teeth that mesh with the rack teeth of the rack plate in one direction, and rotatably fitted to the shaft; The cam plate is fitted into the cap and is fixed to the shaft with a screw, and a spring housed in the cap for applying a pressing force to the rack plate to the cam plate is provided. Adjustment screw with torque limit.