JPH0441134A - Nut tightening device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nut tightening device for permanently tightening a nut that has been pre-tightened to a spindle-shaped workpiece with relatively high torque.

[Conventional technology]

FIG. 5 shows a cross-sectional view of an example of a conventional nut tightening device. In this Fig. 5, a spindle-shaped workpiece 1
The pallet 18 on which 00 is set is supported by rollers 14 of a pallet guide frame 12 provided on a bed (not shown). A socket 266 of a nut runner unit (not shown) is disposed above the pallet 18, and a collet chuck 288 is disposed below the pallet 18.
is located.

In the apparatus shown in FIG. 5, the collet chuck 28
8 is raised from below the pallet 18 to the illustrated position, the collet 288a is inserted into the inner diameter portion of the workpiece 100. At this point, the drawbar 288b is pulled downward,
This causes the collet 288a to open outward and clamp the inner diameter portion of the workpiece 100.

Subsequently, the socket 266 descends from above the work 100 and is pressed against the nut 108. When the socket 266 starts rotating in conjunction with an actuator (nut runner) not shown, the socket 266 is fitted into the nut 108, and then the nut 108 is fully tightened.

Although the types of target workpieces are different, an example of a device equipped with a chuck mechanism and a tightening mechanism that can be used on a boat is the technique disclosed in Japanese Patent Application Laid-Open No. 62-251029.

[Problem to be solved by the invention]

The nut 108 of the workpiece 100, which is the target this time, is tightened with a relatively high torque (maximum 3.000 kg-cm2). For this tightening, the clamping force of the collet chuck 288 may be insufficient in relation to the torque. Although it is possible to increase the clamping force of the collet chuck 288, in this case new problems such as deformation of the inner diameter portion of the workpiece 100 and damage to the collet 288a etc. occur.

Further, since the collet chuck 288 is disposed below the pallet 18 and clamps the workpiece 100 by raising it above the pallet 18, the mechanisms such as the collet 288a become complicated.

Therefore, in reality, it is difficult to employ the pallet 18, and it is difficult to automate the assembly line itself.

Note that as shown in FIG. 6, the work lo.

Even when the outer diameter part of the outer diameter part is clamped by the outer diameter collet 300, almost the same problem as in the case of FIG. 5 remains.

Particularly in the case of FIG. 6, the outer diameter collet 300 is arranged so as to cover the outside of the pallet 18, making it even more difficult to employ the pallet 18.

The technical problem of the present invention is to provide a nut tightening device that can deal with high torque when tightening a nut to a workpiece, and that can easily adopt a pallet system that is optimal for automating the line for assembling the workpiece in brackets. That's true.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention tightens a nut by rotating a tightening shaft from above the spindle-shaped workpiece, and tightens a detent member disposed coaxially with the tightening shaft from above the workpiece around the outer circumference of the workpiece. It is characterized by being held in a non-rotating state by being locked in a concave or convex portion.

In other words, the nut tightening device of the present invention includes a bed on which a spindle-shaped work on which a nut is temporarily tightened and which has a concave or convex portion on a part of the outer periphery is placed in a positioned state, and a bed that can be raised and lowered with respect to the bed. A nut runner unit is operably assembled, a cylindrical tightening shaft is rotatably supported by this unit, and the workpiece is integrated into the tightening shaft from below the tightening shaft. a socket that fits into the nut when inserted coaxially; an actuator that is attached to the unit and applies rotational force to the tightening shaft; and an actuator that is arranged coaxially with the tightening shaft and that A rotation prevention member that locks into the recess or the projection is provided.

[For production]

According to this configuration, by lowering the nut runner unit, the workpiece is inserted into the tightening shaft from below, and as a result, the socket is fitted into the nut from above the workpiece. In parallel with this, the rotation preventing member engages with the concave or convex portion of the workpiece from above, thereby holding the workpiece in a rotation-prevented state. Then, as the tightening shaft rotates, the nut is fully tightened.

Since both the tightening shaft and the rotation preventing member are arranged above the workpiece, the workpiece can be placed on the bed using a pallet.

Therefore, this type of assembly can easily adopt the pallet system, which is optimal for line automation.

〔Example〕

Next, one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

First, FIG. 3 shows a front view of the nut tightening device, and FIG. 4 shows its side view. These figures 3 and 4
In the figure, a column 20 is arranged on the top surface of a bed 10. Further, a pallet guide frame 12 extending in the left-right direction in FIG. 3 is arranged on the bed 10 on the front side of the column 20 (left side in FIG. 4). A pallet 18 is placed on the roller 14 of the pallet guide frame 12.
It is mounted so that it can be moved along 2. Note that a positioning cylinder 16 is provided in a part of the pallet guide frame 12. By operating this cylinder 16, the pallet 18 can be positioned at a predetermined working position.

A nut runner unit 30 is attached to the column 20 so as to be movable up and down. That is, the slider 32 of the nut runner unit 30 is assembled to the column 20 so as to be slidable in the vertical direction by the operation of the lifting cylinder 34.

The slider 32 is provided with a center bracket 38 and a gear box bracket 50 above and below.
are each fixed. The slider 32 is operated by a balance cylinder 36 disposed on the bed 10, so that the lifting and lowering stop position of the nut runner unit 30 can be accurately determined.

FIG. 1 shows a part of FIG. 3 in an enlarged sectional view, and FIG. 2 shows a part of FIG. 1 in a further enlarged view. As is clear from these FIGS. 1 and 2, a spindle-shaped work 100, typified by, for example, a primary sheave assembly of a continuously variable transmission (CVT), is set on the pallet 18. This workpiece 100 has a center hole 102 in its narrow part, and a nut 108 for fixing a bearing 106 is temporarily tightened to a part of the outer periphery. Further, outer spline teeth 110 are formed on the outer periphery of the workpiece 100 near the upper end in the drawing.

Next, in FIGS. 1 and 2, each of the brackets 38
．． The structure of the members assembled to 50 will be explained. First, a center lifting cylinder 40 is assembled to the center bracket 38. Rod 4 of this cylinder 40
1 extends downward, and a center support plate 42 is coupled to the end thereof. A guide rod 44 is fixed to the center support plate 42, and the guide rod 44 is slidably inserted through the center bracket 38. Therefore, the center support plate 42 is guided by the guide rod 44 and can be moved up and down by the operation of the lifting cylinder 40.

A rod-shaped center 46 extending downward is coupled to the center support plate 42 .

The tip of this center 46 is formed into a tapered shape,
It can be inserted into the center hole 102 of the work 100 from above.

On the other hand, a gear box 52 is fixed to the gear box bracket 50. In this gear box 52, a cylindrical intermediate shaft 53 is rotatably supported by a bearing 56 at a position coaxial with the center 46. On the outer periphery of this intermediate shaft 53, there is a gear 54 that meshes with a drive gear 76 to be described below and receives rotational force.
is fixed. Further, a similarly cylindrical tightening shaft 62 is mounted inside the intermediate shaft 53 so as to be movable in the vertical direction with respect to the intermediate shaft 53. Furthermore, the intermediate shaft 53 and the tightening shaft 62 are prevented from rotating relative to each other by a key 64.

A socket 66 that can be fitted into the nut 108 of the workpiece 100 is fixed to the lower end of the tightening shaft 62. Note that a spring 60 is installed between the spring seat 58 fixed to the upper end of the intermediate shaft 53 and the tightening shaft 62, and the tightening shaft 62 is always urged downward.

A drive shaft 74 arranged parallel to the intermediate shaft 53 and the tightening shaft 62 is rotatably supported by a bearing 80 in the gear box 52 . The drive shaft 74 includes the gear 5 of the intermediate shaft 53.
A drive gear 76 meshed with 4 is fixed. The drive shaft 74 is connected to a shaft 72 of a rotation actuator 70 such as an electric motor assembled to the gear box 52.
are connected so that rotation can be transmitted.

A support plate 84 for a rotation preventing member 88 is disposed above the gear box 52 so as to be movable up and down while being guided by a guide rod 82 fixed to the gear box 52. Further, this support plate 84 is prevented from rotating by a rotation-preventing knock pin 86 similarly fixed to the gear box 52, and is always urged downward by a spring 83 assembled to the outer periphery of the guide rod 82.

Furthermore, the support plate 84 is provided at a position coaxial with the center 46, the intermediate shaft 53, and the tightening shaft 62.
A cylindrical anti-rotation member 88 is fixed by a bolt 90 and a knock pin 92. That is, the center 46 is inserted into the locking member 88 from above, and the locking member 88 is inserted into the tightening shaft 62 from above. The outer spline teeth 110 of the workpiece 100 are provided on the inner periphery of the tip of the anti-rotation member 88.
Internal sprue-in teeth 94 are formed that can mesh with the inner sprue-in tooth 94 (see FIG. 2).

Next, the operation of tightening the nut 108 will be explained.

First, the pallet 18 on which the work 100 is set is moved along the pallet guide frame 12, and the positioning cylinder 1 is moved at a position corresponding to the nut runner unit 30.
6 for positioning. Next, the nut runner unit 30
The slider 32 is lowered by the lifting cylinder 34, and before the socket 66 of the tightening shaft 62 and the inner spline teeth 94 of the rotation prevention member 88 are fitted or engaged with the nut 108 and the outer spline teeth 110 of the workpiece 100. Stop at an intermediate position. In this state, the center lifting cylinder 40 is operated to insert the center 46 into the center hole 102 of the workpiece 100.

As a result, the nut runner unit 30 and the workpiece 100 are centered.

Next, the slider 32 of the nut runner unit 30 is further lowered. As a result, if the socket 66 of the tightening shaft 62 is fitted into the nut 108 of the workpiece 100,
Sensor CI shown in FIG. 1 is turned on. Further, the inner spline teeth 94 of the rotation preventing member 88 are connected to the workpiece 100.
Another sensor C2 engages with the outer spline tooth 110 of
turns on.

Therefore, if both sensors CI and C2 are turned on, it is possible to start tightening the nut 108, but this probability is low. Therefore, we will explain the case where a defective state of tightening occurs in the preparation.

First, if the socket 66 of the tightening shaft 62 is not fitted into the nut 108 of the workpiece 100, the tightening shaft 62 will compress the spring 60 against the intermediate shaft 53 as the slider 32 of the nut runner unit 30 descends. Rise. Therefore, the sensor C1 remains off, and a poor fit between the socket 66 and the nut 108 is detected.

Further, if the inner spline teeth 94 of the rotation preventing member 88 do not mesh with the outer spline teeth 110 of the workpiece 100, the support plate 84 is guided by the guide rod 82 together with the rotation prevention member 88 as the slider 32 descends. The spring 83 is compressed and raised. Therefore, the sensor C2 remains off, and the misalignment between the inner spline teeth 94 and the outer spline teeth 110 is detected.

If either of the sensors C1, C2 is off, the shaft 72 of the actuator 70 begins to rotate at a low speed. As a result, the drive shaft 74 also rotates at a low speed, and this rotational force is transmitted to the intermediate shaft 53 through the engagement of the drive gear 76 and the gear 54, and further transmitted from the intermediate shaft 53 to the tightening shaft 62 through the key 64.

As a result, the socket 66 rotates at a low speed, and since the socket 66 is pressed against the nut 1°8 by the biasing force of the spring 60 acting on the tightening shaft 62, the nut 108 is rotated due to the resistance. be done.

Now, when only the sensor C2 is on, that is, when the internal spline teeth 94 of the rotation prevention member 88 are engaged with the external spline teeth 110 of the workpiece 100, the nut 1 that is being rotated by the resistance caused by the pressing of the socket 66
If the torque for tightening 08 is greater than the resistance for this pressing, the socket 66 will slip against the nut 108. As a result, the socket 66 is fitted into the nut 108 by the action of the spring 60.

Further, when only the sensor CI is on, that is, when the socket 66 is already fitted into the nut 108, the nut 108 is tightened by the low speed rotation of the socket 66.
Tightening is started. The tightening torque at this time is the sum of the rotational resistance of the bearing 104 of the workpiece 100 supported on the pallet 18 and the pressing resistance between the rotation prevention member 88 and the end surface of the outer spline tooth 110 by the spring 83. Once the workpiece 100 becomes larger, the workpiece 100 begins to rotate relative to the pallet 18. As a result, the anti-rotation member 88 and the outer spline teeth 110 of the work 100 slide relative to each other, and the inner spline teeth 94 of the anti-rotation member 88 mesh with the outer spline teeth 110 due to the action of the spring 83.

In addition, when both sensors CI and C2 are off,
Although there will be some differences due to the resistance of each part mentioned above,
Fitting of socket 66 to nut 108 and work 1
Detent member 88 for external spline tooth 110 of 00
The meshing of the inner spline teeth 94 is performed almost simultaneously.

When both the sensors CI and C2 are turned on, the actuator 70 is switched to high-speed rotation, and the rotation stopper 8 is turned on.
The nut 108 is fully tightened by high-speed rotation of the socket 66 with respect to the workpiece 100 which is prevented from rotating by the bolt 8 . At this time, the reaction force of the tightening acting on the rotation prevention member 88 acts on the support plate 84, and this support plate 84
is gear box 52. The knock pin 86 fixed to
Uke is stopped by this.

After the nut 108 has been tightened to the workpiece 100, the slider 32 of the nut runner unit 30 is raised to the above-mentioned intermediate position by the lifting cylinder 32, and then the center 46 is raised by the center lifting cylinder 40. Subsequently, the slider 32 is raised to the position shown in FIGS. 3 and 4, and the positioning cylinder 16 is activated into the position of releasing the position of the pallet 18.

This completes the entire cycle of nut tightening.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and includes various embodiments.

For example, the outer spline teeth 110 of the workpiece 100 for locking the rotation preventing member 88 may be grooves or protrusions on the outer circumference of the workpiece 100.

[Effects of the Invention] As described above, the present invention can sufficiently cope with torque when tightening a nut, and furthermore, by tightening the nut from above the workpiece and preventing rotation of the workpiece, the assembly for tightening the nut can be easily handled. This makes it easy to adopt the optimal pallet system when automating the line.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, Figure 1 is an enlarged sectional view of the main part of the nut tightening device, and Figure 2 is a further enlarged part of Figure 1. 3 is a front view of the nut tightening device, and FIG. 4 is a side view thereof. Figure 5 is a sectional view showing a part of a conventional nut tightening device.
FIG. 6 is an explanatory diagram showing a clamping state different from that in FIG. 5 in the same conventional nut tightening device. lO... Bed 30... Natsu runner unit 62... Tightening shaft 66... Socket 70... Actuator 88... Stopper member 100... Work 108... Natsu applicant Toyota Motor Corporation Applicant Chubu Giken Co., Ltd. Agent Patent Attorney Hidehiko Okada (3 others) Figure Figure Figure

Claims (1)

[Claims] A bed on which a spindle-shaped workpiece having a temporarily tightened nut and a concave or convex portion on a part of its outer periphery is placed in a positioned state; a nut runner unit attached thereto, a cylindrical tightening shaft rotatably supported by this unit, and a workpiece integrated with this tightening shaft, into which the workpiece is coaxially inserted from below the tightening shaft. a socket that fits into the nut in a state in which the nut is held in place; an actuator that is attached to the unit and applies rotational force to the tightening shaft; A nut tightening device comprising a locking member and a locking member.