JPS5953133A - Tightening method of article by multispindle nut runner - Google Patents

Abstract

PURPOSE:To shorten a tightening period of time, by a method wherein a large number of nut runners is grouped after tightening of the same temporarily at a time and all of groups are tightened up to the final torque value by repeating the tightening in such a manner that when the torque value of the group previous to the next one is arrived at a middle level, the next group is made to operate. CONSTITUTION:A whole of nut runners 5 is tightened temporarily by a multispindle nut runner 1, to begin with. Then, the nut runners each are grouped in a longitudinal direction and tightening is started from a central group. In this instance, the next group B starts operation when a torque value is arrived at a middle level and similarly a group C starts operation at a middle torque value of the group B. Then the whole of the nut runners are tightened up to the final torque value, through which regular tightening is completed. With this matter, torque down is reduced and a tightening period of time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for tightening articles using a multi-shaft nut runner.

Generally, when tightening an article with a large number of fastening members such as bolts and nuts, strict control of the tightening torque may be required. For example, in an engine assembly process, when bolting a cylinder head to a cylinder block via a gasket, it is important to manage the tightening torque in order to maintain airtightness within the cylinder.

Conventionally, when tightening an article with a large number of fastening members, such as when assembling the engine mentioned above, all the fastening members are divided into groups corresponding to the longitudinal direction of the article, and the tightening members are sequentially tightened in groups from the center group to the end groups. It is generally known that tightening using an intermediate inclusion such as the gasket reduces the torque drop. for example,
Japanese Unexamined Patent Application Publication No. 7626/1997 discloses a proposal to perform the transition from the center side to the end side in groups by detecting the final tightening torque value of the group before the transition.

However, as in the case where the cylinder block is tightened using a multi-shaft nut runner on the engine assembly line,
When it is required to perform tightening work in a short time, "1"
With the method proposed above, it is difficult to sufficiently shorten the working time. In other words, in the case of the method proposed above, the seven groups determine the time it takes to reach the final tightening torque, and the final tightening generates a torque detection signal and sends an activation signal to the nut runner of the next group. This results in a longer tightening operation time.

Additionally, if you simply tighten each group, by the time you finish tightening the final group, you may end up with a torque reduction in other groups that have already been tightened. The actual situation is that the tightening work time on the assembly line is often limited due to the relationship with other processes, and it is not possible to take sufficient time for the additional work.

In view of the above, the present invention has been developed by first temporarily tightening all the fastening parts A, and then dividing the multi-shaft nut runners into groups corresponding to the longitudinal direction of the article during the final tightening, and grouping from the center side to the end side. By detecting that the group before the transition has reached an intermediate torque value smaller than the main tightening torque value, the nut runner operation is transferred in units, thereby reducing the tightening time. This invention provides a method for tightening articles using a multi-shaft nut runner that performs additional tightening work.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below based on embodiments with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a multi-shaft nut runner device, which is used to fasten the cylinder head 2 and cylinder block 3 of an engine with bolts 4 with a gasket placed between them. runner 5
Equipped with The cylinder head 2 of this example is arranged in its elongated direction (
A total of 70 bolt holes are provided in two rows of 5 each in the left and right direction in FIGS. is attached to a head member 7 supported vertically movably on a support column B.

8 is a conveyor device, and each part of the engine is placed on a pallet 9.
That is, the cylinder head 2 and cylinder block 6 are placed in a temporarily assembled state and transported below the nut runner 5 of the multi-shaft nut runner device 1. 10 is a controller.

Next, a method of tightening the cylinder rod 2 and the cylinder block 6 using the nut runner device 1 will be described with reference to FIGS. 1, 2, and 3.

” - Tightening is carried out by the conveyor device 8 after each engine member is conveyed to a predetermined position below the multi-shaft nut runner device. After that, tightening is carried out in the preparation process, temporary tightening is in the process, main tightening is in the process, and additional tightening is in the process. It is to be done in order. The multi-axis nut runner device 1 is
Each nut runner 5 is divided into groups corresponding to the longitudinal direction of the rod 2 to the cylinder, and the nut runner 5 located in the center is
The individual/set nut runners 5 are grouped A, those located on both sides of group A are group B, and those located at both ends are group C.

First, in the school preparation process, the head member 7 is lowered and each nut runner 5 is fitted to the bolt 4 once.

During the temporary tightening process, the controller 10 simultaneously sends an activation signal to the nut runners 5 of each group A, B, and C, and simultaneously tightens all the bolts 4 to a predetermined temporary tightening torque value (in this example, the group Tighten until 6θKgcm). In this case, as shown in the flowchart of Fig. 3(a), it is determined whether the bolts are temporarily tightened to the torque value in each group of A, B, and C, and YES is determined.
If so, a temporary tightening termination signal is issued. And A, B
It is determined whether temporary tightening has been completed for all groups of groups C, and if YES, after a predetermined time period of seconds has elapsed, the main tightening will proceed to the process.

In the main tightening process, each group A, B, and C are divided into groups corresponding to the longitudinal direction of the cylinder head 2.
, the main tightening is performed symmetrically in group units from A group in the center to C groups at both ends with torque value (
Tighten until it reaches ♂00KyLM). That is,
The controller 10 first sends an activation signal to the A group.

When it is determined that the A group has reached an intermediate torque value (J60Kfcm) smaller than the main tightening torque value, the controller 10 sends an activation signal to the B group rape, and the A group continues main tightening. When it is determined that the final tightening has reached the torque value,
A final tightening signal is issued. That is, the actuation signal will be issued to group B before the main tightening of group A is completed.

In group B, when it is determined that the intermediate torque value has been reached, as in group A, an activation signal is sent from the controller 10 to group C, and in group B, main tightening is continued until the torque value is reached. Continued. In group C, in response to the above operation signal, main tightening is performed until the torque value is reached. As above, A, B
When the main tightening of each group of , C is completed in sequence, the presence or absence of the completion signal is determined, and if YES, the process moves to the next additional tightening step.

Additional tightening is done during the process, and main tightening is done at A and B after the process is completed.
, C to each group at the same time, and the final tightening of all bolts 3 at the same time is performed using the torque value (♂θ0 = crn
). That is, as shown in the flowchart of FIG. 3 (bl), A, B.

In each group of C, it is determined whether the final tightening has reached the torque value, and if YES, an additional tightening end signal is issued, and whether or not the additional tightening end signal is issued from all groups. If YES, it is determined whether additional tightening is to be performed twice. If this determination is NO, a process end signal is issued for full tightening, and if YES, after the above-mentioned additional tightening is repeated, a process end signal is issued for full tightening.

In the above tightening method, the rotation speed of the nut runner 5 during temporary tightening is faster than the rotation speed during main tightening and additional tightening, for example, the former is about θ0 rpm, and the latter is about θ0 rpm.
They are each set to about θrpm.

During the main tightening process, when the operation of the nut runner 5 is sequentially transferred from the center to the end side hegel loops,
Since the intermediate torque value is detected and shifted, the time required for the main tightening process is short.Also, if the main tightening is performed sequentially in groups, it usually takes 20 minutes for groups A and B. % torque down,
Furthermore, although this torque reduction may cause a torque reduction in group C, this torque reduction can be reduced to about 2% by additional tightening after the main tightening is completed. Further, since the main tightening process can be performed in a short time, additional tightening can be performed twice, and it is possible to almost eliminate torque reduction.

In the example mentioned above, the same nut runner 5 was used for all tightening processes, but on the assembly line, a multi-axis nut runner device was used for temporary tightening, and a multi-axis nut runner device was used for temporary tightening, and a multi-axis nut runner device was used for temporary tightening, and A multi-axis nut runner device for attachment may be installed in parallel, and temporary tightening, main tightening, and additional tightening may be performed using separate nut runners.

Further, in the above embodiment, the torque value for the main tightening and the torque value for the final tightening are set to the same value, but the torque value for the main tightening may be smaller than the torque value for the final tightening. Furthermore, the intermediate torque value only needs to be smaller than the torque value for main tightening; for example, even if the intermediate torque value is set lower in the above embodiment,
Since it takes some time for the nut runners of the next group to start operating after detecting the intermediate torque value, the tightening order of the groups A, B, and C does not change.

Furthermore, although the above embodiments relate to the assembly of an engine, the present invention can be applied to any case where an article is tightened using a multi-shaft nut runner. Furthermore, it goes without saying that the fastening member to which the nut runner is applied is not limited to bolts, but may also be nuts.

As described above, according to the present invention, when performing main tightening by sequentially moving from the center side to the end side Hegel loop unit, the group before the transfer has an intermediate torque value smaller than the torque value for main tightening. Since the system detects the actual tightening and then shifts to the next step, the time required for main tightening can be reduced compared to the conventional method, and by taking advantage of this time reduction and performing additional tightening on all fastening members at the same time, the torque can be reduced. An excellent effect can be obtained in that the down size can be reduced.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention; FIG. 1 is a partially sectional front view showing the relationship between the multi-axis nut runner device and the article; FIG. 2 is a sectional view taken along the line ■-■ of FIG. 1; Figure 3 (al is a flowchart showing the process for temporary tightening and the process for main tightening, Figure 3 (bl is a flowchart for the process of additional tightening). 1...Multi-axis nut runner Device, 2...
・Cylinder head, 3...Cylinder block,
4...Bolt, 5...Natsu runner, 10...Controller patent applicant Toyo Kogyo Co., Ltd. (11) Figure 1, Figure 20

Claims (1)

[Claims] (1) A method for fastening articles using a number of fastening members, in which each of these fastening members is tightened using a nut runner. First, all the fastening members are simultaneously tightened using a nut runner to a temporary tightening torque, and then,
When all the nut runners are divided into groups corresponding to the longitudinal direction of the article and the main tightening is performed symmetrically sequentially in groups from the center to the end side, the second and subsequent groups are divided into groups seven groups earlier. It is characterized in that it is activated to perform the main tightening when the torque reaches an intermediate torque value smaller than the main tightening torque, and then all the fastening members are simultaneously tightened by each nut runner until the final tightening torque is reached. A method for tightening articles using a multi-axis nut runner.