JPH0637010B2 - Tightening control method for preload adjustment - Google Patents

Description

The present invention relates to a shaft member such as a drive pinion rotatably supported by a housing member such as a differential device of a vehicle through a bearing. The present invention relates to a preload adjustment tightening management method for automatically applying a desired rotation resistance (preload) to the.

(Prior Art) A vehicle differential device includes a housing 1 as shown in FIG.
And a drive pinion shaft 4 rotatably supported by the housing 1 via front and rear taper roller bearings 2 and 3, and a spline fit to the drive pinion shaft 4, and an inner race of the taper roller bearing 2. The companion flange 5 that abuts on the drive pinion 2a is screwed to the tip screw portion 6 of the drive pinion shaft 4 to attach the companion flange 5 to the drive pinion shaft 4, and the inner race 2a is pressed through the companion flange 5 to drive the inner race 2a. The pinion shaft 4 has a pinion nut 7 that imparts a desired rotation resistance (preload) to the housing 1. A bolt insertion hole 8 is formed in the companion flange 5, and a pinion gear 9 is fixed to the drive pinion shaft 4.

The preload applied to the drive pinion shaft 4 is
Usually, it can be automatically set by a tightening device for preload adjustment (see, for example, Japanese Patent Publication No. 56-4969).
That is, this preload adjusting tightening device has a nut rotation drive system for rotating the pinion nut 7, and a pin inserted into the bolt insertion hole 8 of the companion flange 5 to insert the pin into the companion flange 5, that is, the drive pinion shaft. 4 is independently provided with a companion flange rotation drive system for rotating 4. And drive pinion shaft 4
In a state in which the center is rotatably supported from above and below, the nut rotation drive system and the companion flange rotation drive system are driven to move the pinion nut 7 and the drive pinion shaft 4 so that the rotation speed of the pinion nut 7 is the drive pinion shaft 4. The rotational speed of the pinion nut 7 is rotated in the same direction in a manner higher than the rotation speed of the pinion nut 7, and the pinion nut 7 is fastened to the drive pinion shaft 4. By tightening the pinion nut 7, the companion flange 5 moves in the axial direction, and the taper roller bearing 2
The inner race 2a of is pressed in the axial direction,
Rotational resistance is generated between the bearing 2 and the outer race 2b fixed to the housing 1, and as a result, rotational resistance (preload) to the housing 1 is imparted to the drive pinion shaft 4.

Since the drive pinion shaft 4 is rotated here, a rotational torque based on the preload is generated in the housing 1. Therefore, if the rotational torque of the housing 1 is measured, the preload can be measured. When the rotational torque reaches a predetermined value, both rotary drive systems are stopped or the drive pinion shaft 4 and the pinion nut 7 are stopped. By rotating and at the same speed in the same direction, the relative rotational speed difference is eliminated, so that the drive pinion shaft 4 is given a preload of a desired value.

By the way, in the conventional preload adjusting tightening device as described above, at the start of tightening the nut, high-speed tightening is performed by rotating the nut. By switching to, it is attempted to give an accurate preload in a short time, but since the tightening torque value is used as a reference when switching from high speed to low speed, this reference value is set to a proper preload value. Before reaching, the margin is set below the lower limit of the preload value with a margin, and therefore the tightening time after switching to the low speed tends to be long.

On the other hand, if the number of rotations at low speed is increased in order to shorten the tightening time, the influence of inertia of the rotary drive system and the like becomes large, and the accuracy of the preload value deteriorates.

(Object of the Invention) The present invention solves the above-described conventional problems, and preload adjustment tightening management capable of performing accurate preload tightening without taking time while suppressing the rotational speed of low speed tightening. The purpose is to provide a method.

(Structure of the Invention) According to the present invention, a nut is screwed onto a shaft member rotatably supported by a housing member via a taper bearing by using a nut runner, and the taper bearing is provided with the degree of tightening of the nut. In the tightening management method for preload adjustment, which adjusts the pressing force in the axial direction, thereby preliminarily imparting a predetermined rotation resistance to the housing member to the shaft member, while performing high-speed tightening rotation of the nut runner, Detection is performed, and when this detected value reaches a value near the lower limit of the set preload value, switching to low speed tightening rotation is performed, the tightening torque value is detected while performing this low speed tightening, and the detected preload value reaches the set preload value. After that, the actual preload value is detected.

According to this method, since switching from high-speed tightening to low-speed tightening is controlled based on the preload value without using the tightening torque value as a reference, it is necessary to switch to low-speed tightening early with a large margin. Therefore, the tightening time after switching to the low speed tightening is shortened while setting the rotation speed at the low speed tightening low, and the accuracy of preload tightening can be improved.

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

FIG. 1 is an explanatory view showing in principle the configuration of the main parts of a preload adjusting tightening device for carrying out the method of the present invention, in which W is the second
The part of the differential device described in the figure (hereinafter referred to as "work") is shown, and the pinion nut 7 of the work W is temporarily fixed to the tip of the screw portion 6 of the drive pinion shaft 4.

Reference numeral 10 denotes a rotary drive head which is arranged so as to be movable up and down, and an inner shaft 11 and an outer shaft 11 which are arranged so as to be relatively slidable along an axis line in the vertical direction and relatively rotatable around the axis line. And a shaft 12. A socket (nut runner) 13 forming a box wrench for tightening the pinion nut 7 of the work W is provided at the lower end of the inner shaft 11, and the upper end of the drive pinion shaft 4 of the work W is provided at the center of the inner shaft 11. The cushion center 14 inserted into the opened center hole is fitted slidably in the axial direction, and the spring 1
5 is urged downward. A pin 16 inserted into a bolt insertion hole 8 formed in the companion flange 5 of the work W is provided at the lower end of the outer shaft 12 so as to project downward.

Reference numeral 17 is a hydraulic cylinder for raising and lowering the work W, and a center 19 for supporting the drive pinion shaft 4 of the work W from below is provided at the upper end of a piston rod 18 thereof.

Reference numeral 21 is a controller for controlling the preload adjusting tightening device. The controller 21 includes a torque allowance device 22 for setting an allowable peak value of the tightening torque during the tightening operation of the device, and a high-speed tightening rotation to a low-speed tightening rotation. The values set by the first preload setter 23 for setting the reference value for switching to the second preload setter 23 and the second preload setter 23 for setting the allowable value of the final preload actual measurement value are input. Further, the detected values from the torque detector 30 and the preload detector 32, which will be described later, are input, and predetermined determination, comparison and control as will be described later are performed, and the motor controller 25 and the preload and torque determination display means 33 and 34 described later are connected. It outputs a driving signal.

Reference numeral 26 denotes a motor which is a rotary drive source of the rotary drive head 10. The motor 26 controls the rotational speed of the motor 26, and the output thereof is transmitted to the gear box 27. Although illustration is omitted, a reduction gear and an electromagnetic clutch are incorporated in the gear box 27,
From the gear box 27 to the inner shaft 1 of the rotary drive head 10.
A nut rotation drive system 28 for driving 1 and a companion flange rotation drive system 29 for driving the outer shaft 12 are derived.

The nut drive rotation system 28 and the companion flange drive system 29 increase the relative rotation speed difference between the nut drive rotation system 28 and the companion flange drive system 29 so that the inner shaft 11 and the socket 13 rotate at a relatively high speed with respect to the outer shaft 12. 7 is fastened at a high speed, and thereafter, when a predetermined preload value described later is reached, the relative rotational speed difference between the two is reduced to switch to a low speed tightening rotation. The switching from the high speed tightening to the low speed tightening is configured to be performed by a switching signal from the controller 21 to the gear box 27 without changing the rotation speed of the motor 26.

Reference numeral 30 denotes a torque detector provided on the nut rotation drive system 28 for detecting a tightening torque during a tightening operation, and 31 is interposed in the companion flange drive system 29 to intermittently connect the outer shaft 12 side and the drive source side. With this electromagnetic clutch, by turning off this electromagnetic clutch 31, the outer shaft 12 side can be freed from the drive source, whereby the inner shaft 11 and the companion flange rotary drive source 29 by the nut rotation drive system 28 can be made free. The relative rotational speed difference with the outer shaft 12 disappears, and the so-called no-load rotation of the drive pinion shaft 4 is performed by the nut rotation drive system 28, and the actual preload value can be detected in this state.

Reference numeral 33 is a preload determination display means for displaying whether or not the measured preload value is in the range of the allowable preload value determined by the second preload setting device 24, and 34 is the peak hold value of the detected tightening torque set by the torque setting device 22. Torque determination display means for displaying whether or not the range of the allowable set torque value is set, and both are driven by the controller 21.

Next, the operation of the above configuration will be described. Drive pinion shaft 4
The work W having the pinion nut 7 temporarily fixed to the tip of is set between the rotary drive head 10 and the hydraulic cylinder 17,
The rotary drive head 10 descends to insert the pinion nut 7 of the work W into the socket 13 of the inner shaft 11, and the pin 16 of the outer shaft 12 into the bolt insertion hole 8 of the companion flange 5 of the work W. And hydraulic cylinder 1
7 is operated to raise the piston rod 18, and its center 19 is inserted into the center hole at the lower end of the drive pinion shaft 4 of the work W to support the drive pinion shaft 4. Thus, the work W is rotatably supported between the cushion center 14 of the rotary drive head 10 and the center 19 of the piston rod 18, and the housing 1 of the work W is in a free state.

Next, the operation of tightening the pinion nut 7 and adjusting the preload by the controller 21 in this state will be described with reference to the flowchart shown in FIG.

First, in step S ₁ , the nut rotation drive system 28 and the companion flange rotation drive system 29 drive the socket 13 at a low relative rotation speed with respect to the gearbox 27 for a predetermined period determined by a timer or the like, and the socket 13 is rotated at a low speed. Is stabilized, the process proceeds to step S ₂ , where the nut rotation drive system 28 and the companion flange rotation drive system 2
The relative rotational speed difference of 9 is increased, so that the socket 13 is driven to rotate at high speed. Then, while performing the fast clamping rotation, in step S _3, to measure the pre-load value by preloading detector 32. Pinion nut 7
When the tightening is advanced, the seat is seated on the companion flange 5 and the inner race 2a is pressed, a rotational resistance (preload) is generated between the drive pinion shaft 4 and the housing 1, which causes the housing 1 to move. Starting to rotate, the preload value gradually increases.

In step S ₄ , it is determined whether or not this preload measurement value has reached the lower limit value of the set preload value set by the first preload setter 23. If NO, step S ₂
The return, if YES is switched to the low speed tightening rotate the socket 13 to reduce the relative rotational speed difference between the nut rotation drive system 28 and the companion flange rotary drive system 29 at step S _5.

Further subsequently have subjected to pre-load measurement at step S ₆ and determines whether or not reached the set set pre-load value by the first preload setting unit 23 at step S _7. If this determination result is NO the process returns to step S _5,
If YES allowed to a no-load rotation proceeds to step _{S 8.} That is, the electromagnetic clutch 31 is turned off, the outer shaft 12 on the companion flange rotation drive system 29 side is freed from the inner shaft 11 on the nut rotation drive system 28 side, the pinion nut 7 is driven, and the drive pinion shaft 4 side is unloaded. It is rotated, and in this state, the actual preload value is measured by the preload detector 32 in step S ₉ .

It is determined whether or not the actual pre-load value at step S ₁₀ and subsequently is in a range of acceptable preload value set by the second preload setter 24, in step S ₁₁ when it is in the range of acceptable values If OK is displayed and if it is out of the range, NG is displayed in step S ₁₂ . These displays are performed by the preload determination display means 33.

Also, the measurement of the tightening torque by the torque detector 30 in step S ₁₃ while performing a slow tightening rotation of the socket 13 in step S _5. Further step S ₁₄
At holding the peak value of the tightening torque in the tightening torque measurement, the peak value of the clamping step S ₁₅ it is determined whether or not the range of the set permissible torque value by the torque setter 22, the determination results if YES forms a OK displayed in step S _16, when the NO constitutes an NG displayed in step S _17. These displays are performed by the torque determination display means 34.

As described above, while performing the high-speed tightening rotation of the socket 13, the preload value is detected, and when the detected value reaches the lower limit of the set preload value, it is switched to the low-speed tightening rotation. Compared to the one that switches from high-speed tightening to low-speed tightening based on, the high-speed tightening can be performed as close as possible to the preset preload value, so the tightening time after switching to low-speed tightening will not be long, Therefore, it is possible to suppress the rotational speed of low-speed tightening to a low level for highly accurate preload tightening adjustment, and to reduce variations in preload value due to rotational inertia.

In the above embodiment, the switching from high-speed tightening to low-speed tightening is shown based on the lower limit of the set preload value, but this reference value may be a value near the lower limit of the set preload value.

As described above, according to the present invention, the preload value is detected while performing the high-speed tightening rotation of the nut runner, and the low speed tightening is performed when the detected value becomes a value near the lower limit of the set preload value. By switching to rotation and performing this low-speed tightening, the tightening torque value is detected, and the actual preload value is detected after the detected preload value reaches the set preload value. As compared with the case of switching from high speed tightening to low speed tightening, the tightening time can be shortened while suppressing the rotation speed of low speed tightening, and highly accurate preload tightening can be performed without spending time.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of a device for carrying out the preload adjusting tightening management method of the present invention, FIG. 2 is a sectional view of a differential device in which the method of the present invention is carried out, and FIG. 3 is the method of the present invention. 3 is a flowchart of control by the. 1 ... Housing (housing member), 2, 3 ... Tapered roller bearing, 4 ... Drive pinion shaft (shaft member), 7 ... Pinion nut (nut), 10 ... Rotary drive head, 13 ... Socket (nut runner) ), 21
...... Controller, 30 ...... Torque detector, 32 ...... Preload detector.

Claims (1)

[Claims] 1. A nut is screwed onto a shaft member, which is rotatably supported by a housing member via a taper bearing, by using a nut runner, and the axial direction given to the taper bearing is determined by the degree of tightening of the nut. In a tightening management method for preload adjustment in which a pressing force is adjusted and thereby a predetermined rotation resistance with respect to the housing member is given to the shaft member in advance, a preload value is detected while performing high-speed tightening rotation of the nut runner, When this detected value reaches a value near the lower limit of the set preload value, switching to low speed tightening rotation is performed, the tightening torque value is detected while performing this low speed tightening, and the actual preload is performed after the detected preload value reaches the set preload value. A tightening management method for preload adjustment, which is characterized by detecting a value.