JPH0422902Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a mechanism for preventing rotation when tightening an object such as an axle with a nut runner.

(Prior Art) In a structure in which the work rotation center and the tightening rotation center coincide, for example, as shown in FIG. 3, an axle 17 is attached to an automobile drive shaft 20 and integrated with a nut 5. When tightening the nut 5 with a nut runner, unless a rotation prevention means is provided, the axle 17 will rotate together with the nut 5 and cannot be tightened. For this reason, in the prior art, the hub bolt 18 of the axle 17 is used to prevent rotation.

4 and 5 show a conventional tightening and rotation prevention mechanism, in which a plurality of reaction force receiving members 25 that engage with hub bolts 18 are fixedly provided on the base 1 of the nut runner 2 having a socket portion 6. It is being In this case, since the reaction force receiving member 25 is fixed to the base 1 of the nut runner 2, there is a gap between the reaction force receiving member 25 and the hub bolt 18 in the tightening rotation direction before tightening, and the nut runner When tightening by 2 is started and the nut 5 is seated on the axle 17, the axle 17 begins to rotate by the amount of the gap. As a result, the hub bolt 18 contacts and engages the reaction force receiving member 25 from the rotational direction, thereby preventing rotation of the axle 17 and allowing the nut 5 to be tightened.

(Problem to be Solved by the Invention) However, according to the above-mentioned prior art, after the nut 5 is seated, the axle 17 rotates due to the driving force of the nut runner 2, causing the hub bolt 18 and the reaction force receiving member 25 to rotate. Because the two impact each other, the reaction force receiving member 25 may be easily deformed. When the reaction force receiving member 25 deforms,
The hub bolt 18 may be damaged, causing the hub nut to seize.

In view of the above-mentioned problems, the present invention minimizes damage to the reaction force receiving member and the fastened object by engaging the reaction force receiving member with the protrusion of a hub bolt, etc. without causing the fastened object to rotate. The purpose of the present invention is to provide a tightening mechanism that prevents the rotation from rotating to a minimum.

(Means for Solving the Problems) The technical means of the present invention includes a nut runner for tightening an object to be tightened, a base for supporting the nut runner, and a flat plate having a notch that engages with a protrusion of the object to be tightened. An outer frame body is disposed on the base and is rotatably driven independently of the socket portion of the nut runner, and a reaction force receiver portion is provided on the outer frame body so as to be integrally rotatable with the nut runner. , elastically biasing the reaction force receiving member toward the tip of the socket portion against the outer frame body;
The detection means detects the engagement between the protrusion and the reaction force receiving member,
The output signal of the detection means is sent to the rotational drive source of the outer frame to stop it.

In the present invention, the outer frame is disposed outside and coaxially with the rotating shaft of the nut runner, and the rotational drive source for the outer frame is provided in the base. The output of the rotational drive source is transmitted to the outer frame via the worm gear mechanism to rotate it at a low speed.

The protrusions of the object to be tightened are hub bolts, step portions, etc., and the reaction force receiving member is formed with engaging recesses or notches corresponding to the number of the protrusions. The reaction force receiving member is connected to the outer frame body by means such as a key so as to rotate together with the outer frame body, but is provided so as to be slidable in the axial direction of the nut runner. The reaction force receiving member is always urged toward the distal end of the socket, that is, toward the object to be tightened, by a spring or the like interposed between the reaction force receiving member and the outer frame. This is because when the rotational position (phase) of the reaction force receiving member and the protrusion do not match,
This is to absorb external force acting on the reaction force receiving member from the protrusion.

(Function) In the present invention, before the nut runner is tightened, the outer frame is rotated independently of the socket part by the rotational drive source, and the reaction force receiving member is accordingly rotated integrally with the outer frame. . When the reaction force receiving member is rotationally displaced to a phase that matches the protrusion of the object to be tightened, the reaction force receiving member elastically moves toward the object to be tightened by the biasing means, and the protrusion of the object to be tightened moves elastically to the side of the object to be tightened. The reaction force receiving member contacts and engages with. Completion of engagement between the two is detected by the detection means, and an output signal thereof is sent to the rotational drive source to stop the rotation of the outer frame and the reaction force receiving member. after that,
The nut runner operates to tighten the nut and prevent the object being tightened from rotating.

(Example) An example of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a base, 2 is a nut runner fixed to the base 1, and an extension bar 4 is rotatably connected to a rotating shaft 3 of the nut runner 2. extension bar 4
A socket portion 6 for tightening the nut 5 is attached to the tip of the nut 5, and this socket 6 is urged toward the tip by a spring 7.

Reference numeral 8 denotes a rotating body (outer frame body) rotatably installed inside one side 1a of the base 1 via a bearing 29.
A worm gear 9 is fixed to the outer peripheral surface of the rotating body 8. The worm gear 9 meshes with a worm wheel 10 disposed on one side of the base 1, and the worm wheel 10 engages with an electric motor 11 disposed on the outer periphery of the base 1, as shown in FIG.
is connected to. Therefore, although the rotating body 8 is rotationally driven by the electric motor 11 via the worm gear 9 and the worm wheel 10, the rotational force due to the reaction force at the time of tightening is not transmitted.

Reference numeral 12 denotes a hollow piston that is slidably inserted into the inside of the rotating body 8, and is connected to the rotating body 8 by a key 13 so that it can rotate integrally with the piston. piston 12
is urged toward the distal end (leftward in FIG. 1) by three springs 14 against the rotating body 8. Note that the three springs 14 are connected to the piston 12.
are installed at equal intervals around the circumference.

An annular reaction force receiving member 15 is fixed to the tip of the piston 12, and cutouts (engaging portions) 1 are formed on the outer periphery of the reaction force receiving member 15 at equal intervals in the circumferential direction.
6 are formed in accordance with the number of hub bolts 18. As shown in FIG. 2, these notches 16 are provided extending in a radial direction centering on the socket part 6, and are configured so that hub bolts 18 of the axle 17 can be engaged with the notches 16. The reaction force receiving member 15 is provided on the outside of the reaction force receiving member 15.
A detection means 19 is provided for detecting that the hub bolt 18 has come into contact with the side surface of the hub bolt 18.
is fixed to the base 1 side via a bracket 20.

In the above configuration, it is possible to eliminate the twisting of the axle 17 when the nut 5 is tightened by the following operation. First, the entire device is advanced toward the axle 17 by a drive device (not shown), and the socket portion 6 of the nut runner 2 is fitted into the nut 5. In this case, when the reaction force receiving member 15 is not in phase with the hub bolt 18, the tip of the hub bolt 18 hits the front surface of the reaction force receiving member 15, and the reaction force receiving member 15 is pushed back. , this movement is absorbed by the spring 14.

Next, when the socket part 6 is fitted into the nut 5, the electric motor 11 is activated and the worm wheel 1 is turned on.
The rotating body 8 rotates via the worm gear 9 and the worm gear 9. As a result, the reaction force receiving member 15 is attached to the axle 1.
When the piston 12 is rotated to a phase that matches the hub bolt 18 of No. 7, the piston 12 slides forward with respect to the rotating body 8 due to the force of the three springs 14, and the notch 16 of the reaction force receiving member 15 is formed on the side of the hub bolt 18. It hits and engages.

The notch 16 of the reaction force receiving member 15 is connected to the hub bolt 1.
8, the detection means 19 detects this,
When this signal is sent to the electric motor 11, the operation of the electric motor 11 is stopped. After that, the hub bolt 1 of the axle 17 is inserted into the notch 16 of the reaction force receiving member 15.
8 is engaged, the nut runner 2 is rotationally driven to tighten the nut 5 with the socket portion 6. Therefore, even after the nut 5 is seated on the axle 17 by tightening with the socket part 6, the rotating body 8 does not rotate due to the reaction force when the nut 5 is tightened, so the nut 5 and the axle 17 can rotate together. The nut 5 can be tightened without any trouble.

The reaction force receiving member 15 according to this embodiment uses the side surface of the hub bolt 18 as a guide surface and the spring 14 as a guide surface.
Because it elastically moves toward the hub bolt 18 and engages with the force, the reaction force receiving member 15 is prevented from being deformed or the hub bolt 18 is prevented from being damaged.

Even if the axle 17 is clamped during tightening, the axle 17 does not rotate as in the conventional case, so it is possible to eliminate scratches on the axle 17 caused by the clamp.

(Effect of the invention) As mentioned above, the tightening rotation prevention mechanism of the present invention has the following advantages:
Since the reaction force receiving member is engaged with the protrusion of the tightened object from the axial direction of the socket portion without causing the object to be tightened to rotate, the reaction force receiving member can be prevented from being damaged or deformed as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the present invention;
Fig. 2 is a front view with only the upper part of the one shown in Fig. 1 in section, Fig. 3 is a sectional view showing the assembled state of the drive shaft and axle, and Fig. 4 is a side sectional view showing a conventional tightening mechanism. , FIG. 5 is a front view of the one shown in FIG. 1... Base, 2... Nut lamp, 3... Rotating shaft, 5... Nut, 6... Socket part, 8...
Rotating body (outer frame body), 9... Worm gear, 10...
... Worm wheel, 11 ... Electric motor, 12
... Piston, 13 ... Key, 14 ... Spring, 15 ... Reaction force receiving member, 16 ... Notch (engaging part), 17 ... Axle, 18 ... Hub bolt,
19...Detection means.

Claims (1)

[Scope of utility model registration request] An outer frame body that rotates independently of the socket portion of the nut runner is disposed on a base that supports the nut runner, and the outer frame body has a flat plate shape in which a cutout portion that engages with the protrusion of the object to be tightened is formed. A reaction force receiving member is resiliently biased toward the distal end of the socket portion and is provided to be rotatable integrally with the outer frame body, and detects engagement between the protrusion and the reaction force receiving member to release the reaction force receiving member from the outer frame body. A tightening rotation prevention mechanism characterized by comprising a detection means for outputting a stop signal to a rotational drive source.