JPH0513790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a bolt/nut tightening tool used in the nut rotation angle method, which is one of the bolt/nut tightening methods.

(Prior art and its problems) There are two methods for tightening bolts and nuts: the "nut rotation angle method" and the "torque method."

The nut rotation angle method is a bolt/nut tightening method that manages bolt axial force by controlling the rotation angle of the nut to a predetermined angle from the temporary tightening state to the completion of tightening. The bolt axial force is managed by controlling the applied torque to a predetermined value.

The tightening tool used in the torque method can relatively easily measure and control torque using a strain gauge, motor load current, or the like.

The rotation angle method bolt tightening machine temporarily tightens the bolt to be tightened to 5 to 10% of its bolt proof strength, uses the temporary tightening state as a starting point, and detects the rotation angle of the bolt from that starting point. The axial force of the bolt is managed by stopping the rotation of the tightening socket the moment the rotation angle reaches the required rotation angle (120 to 270 degrees).

As an example of a rotary tool used in the above-mentioned rotation angle method, Japanese Patent Publication No. 56-4391 shown in FIG. The angle sensor 81 is used to measure the rotation angle of the socket 7. In this case nut N and socket 7
If there is any play in the fitting or the reaction force receiver 6 of the tightening machine is
In order to avoid including the idling angle until it hits other members such as _B1 in the measurement value, a detector 82 that detects when the reaction force receiver 6 hits an adjacent member is installed on the reaction force receiver 6.
A control box 8 is attached to the electric motor 13.
4 must be repeated in succession, which complicates measurement and control and increases the size of the entire device.

Furthermore, the biggest problem during work is that the angle sensor 81 is provided on the fastener body 83, so in order to obtain a reference point for measurement, the fastener main body 83 including the operation handle 12 and the reaction force receiver 6 must be connected. It must be connected in a fixed state, and therefore, the entire body must be rotated during phase alignment when fitting the socket to the nut, and the body, including the handle, must be rotated until the reaction force receiver 6 hits the adjacent member. The machine rotated and the worker was moved around, which was dangerous.

Further, a handle portion 12 is provided protruding from the fastener body 83, and the angle of the handle portion 12 with respect to the tightening direction changes due to idle rotation of the reaction force receiver 6, making it difficult to support and operate the fastener. Become.

Apart from the above, some rotary tools for the nut rotation angle method that have been put into practical use measure the load current of the motor, and when this value exceeds a certain value, the change in the measured value of the rotary encoder is used. There is a method that measures the rotation angle of the socket. However, the mechanism and circuit for measuring this load current are similar to those used in torque method fasteners, and are similar to those used in torque method fasteners with the addition of a rotary encoder and its control circuit. You can say that. Therefore, due to the complicated structure, not only the main body of the fastener becomes large, but also large control boxes must be installed in succession, resulting in poor work efficiency. Also, the inertia of the electric motor may cause the socket and nut to become jammed,
This may cause the nut to be over-tightened, resulting in problems with tightening accuracy. Furthermore, since a difference in load current cannot be detected unless the load applied to the motor increases to a certain extent, it is necessary to tighten the nut in advance to a value greater than that which can be detected by the tightening tool. Therefore, it may not be possible to use it for small bolts and nuts with low tightening force, and the range of application is limited. In addition, since the rotary encoder is installed on the fastener body,
As mentioned above, the reaction force receiver and the fastener main body must be connected in a fixed state, and when the reaction force receiver idles, it causes problems such as rotation, which is dangerous.

However, compared to the torque method, the nut rotation angle method has the advantage of being easier to handle bolts because there is less variation in the bolt axial force caused by the bolt itself. The nut rotation angle method is becoming more and more popular, as it is used when using galvanized weather-resistant bolts that cannot be tightened due to large fluctuations in the torque coefficient value using the torque method. It has been desired to develop a nut rotation angle method fastener that is smaller, lighter, and capable of tightening with high precision.

The present invention moves a rod built into the output shaft in the axial direction according to the relative rotation angle between the output shaft and the input shaft, which have successive sockets, and detects the rotation angle of the nut based on the amount of this movement. The present invention discloses a bolt/nut fastener that can solve the above problem by controlling the rotation of the socket.

(Means for Solving the Problems) The bolt/nut tightening tool of the present invention includes a socket drive mechanism 7 that drives a socket 7 via a clutch 2 and a differential speed reduction device to a rotary drive device such as an electric motor 13.
1, a detection rod 51 that is slidably disposed astride the axes of the output shaft 46 and input shaft 41 of the planetary gear reduction mechanism 4, and a detection rod 51 that is slidably disposed astride the axes of the output shaft 46 and input shaft 41 of the planetary gear reduction mechanism 4; 51; a control device 9 that operates the detection rod moving device 5 when a nut tightening load is applied to the socket 7; and a clutch disconnection device 28 that disengages the clutch 2 when the rod moves backward. and,
Reaction force receiver 6 that receives the tightening reaction force when tightening bolts and nuts
The handle portion 12 of the fastener is rotatably attached to the reaction force receiver 6.

(Operations and Effects) Since the nut rotation angle is detected by the mechanical means of moving the rod, there is no need to provide a control box as in the past, improving work efficiency and simplifying the configuration. Further, by installing the clutch, it is possible to prevent the socket and the nut from becoming jammed when tightening is completed, and to prevent the nut from being over-tightened due to the inertial force of the rotary drive device, thereby making it possible to control the rotation angle with less error.

Since the rotation angle is detected at a location very close to the nut, errors caused by the "twisting" of the reduction gear itself can be minimized, making it possible to control the rotation angle with high precision.

In addition, unlike conventional systems, there is no need to fix the reaction force receiver and the fastener body, so even when the reaction force receiver is idling until it hits an adjacent member, the operator can easily tighten the main body as the reaction force receiver idles. There is no inconvenience caused by rotation, and operation can be performed from any direction with a small holding force, which is advantageous in terms of workability and safety.

(Embodiment) As shown in FIG. 1, the fastener of the embodiment uses a planetary gear reduction mechanism 4 as a differential reduction device, connects the output shaft 46 of the planetary gear reduction mechanism to the socket 7, and connects the reaction force receiver 6. After the socket 7 idles until it hits an adjacent member (not shown), the relative relationship between the input shaft 41 and the output shaft 46 of the planetary gear reduction mechanism 4 changes from the point at which the socket 7 starts rotating the nut N fitted thereto. The rod 51 built into the output shaft 46 is moved in the axial direction according to the relative rotation angle (hereinafter referred to as the relative rotation angle), and the rotation angle of the nut N is detected based on the amount of movement and the socket 7 is controlled. It is something to do.

In the planetary gear reduction mechanism 4, in order to input torque to the input shaft 41 and obtain output from the output shaft 46,
The relationship between the rotation angles of the input shaft and output shaft at this time is
If the rotation ratio is i, the input shaft rotation angle is _R1 , and the output shaft rotation angle is R3, then R1=iR3... However, i>1 Also, if the relative rotation angle between the input shaft and the output shaft is △R, then △R=R ₁ −R ₃ ..., so substituting the formula into this, △R=(i-1)R ₃ ... becomes. Therefore, R ₃ becomes R ₃ =ΔR/(i-1)...

Since the rotation ratio i is a constant and is known in advance, the output shaft rotation angle R ₃ can be determined from the relative rotation angle ΔR.

As mentioned above, this fastener converts the rotation angle of the output shaft into the amount of movement in the axial direction of the rod 51 built into the output shaft, and the output shaft rotation angle is indirectly detected from the amount of movement. be.

This fastener consists of a power part 1 and an output part 3. A handle part 12 is protruded from a case 11 of the power part 1, and the case 31 and the case 31 of the output part 3 are connected to the input shaft of the planetary gear reduction mechanism 4. It is fitted in such a way that it can rotate freely around 41.

The power unit 3 is equipped with an electric motor 13, a clutch 2 that transmits and interrupts the rotation of the electric motor to the input shaft 41 of the planetary gear reduction mechanism 4, and a trigger 26 that controls switching of the clutch 2 and energization of the electric motor. .

The clutch 2 has a rotating shaft 20 of the electric motor and a clutch output shaft 29 arranged concentrically, and has bevel gears 21 and 22 at opposing ends of both shafts, so that transmission is perpendicular to both shafts and capable of approaching and separating from both shafts. The transmission bevel gear 24 is moved in the axial direction by a toggle 25 operated by a cam surface 27 formed on the trigger 26.
1 and 22 are engaged or separated to transmit or cut off the rotation of the electric motor 13 to the clutch output shaft 29.

The toggle 25 is also operated by a rod 51 which will be described later, and the toggle 25, rod 51 and trigger 26
This constitutes a clutch disconnection device 28.

Furthermore, the bevel gears 21 and 22 and the transmission bevel gear 24 can be configured by friction wheels, or can be configured by axially opposing meshing teeth and a toggle mechanism suitable for operating them. However, the clutch disconnection device 28 is not limited to this embodiment.

At the tip of the clutch output shaft 29 is a gear 23 that meshes with the input shaft 41 of the planetary gear reduction mechanism 4 as described later.
is formed.

Two switches 15 and 16 are provided in the energizing circuit 14 for the electric motor 13, and each switch is connected to push shafts 17 and 18 and springs 19 and 19, which are activated by the movements of the toggle 25 and trigger 26, respectively. ing.

The planetary gear reduction mechanism 4 disposed in the output part case 31 includes an input shaft 41, an output shaft 46 disposed concentrically with the input shaft 41, a sun gear 54 on the input shaft 41 supported by the output shaft 46, and a sun gear 54 on the input shaft 41. Output part case 31
and an idle gear 44 that meshes with internal teeth 40 formed on the inner surface of the shaft.

The input shaft 41 rotatably penetrates the rear wall of the output part case 31 and the front wall of the power part case 11, projects into the case 11, and has a large gear 43 at the projecting end that meshes with the clutch output shaft 29. There is.

A socket 7 is fitted to the tip of the output shaft 46 so as to be able to rotate integrally with the shaft 46, and the electric motor 13, clutch 2, and planetary gear reduction mechanism 4 form a socket drive device 71.

A rod 51 passes through the input shaft 41 and output shaft 46.
is slidably disposed and biased toward the socket 7 by a spring 54. The power section 1 side of the rod 51 is formed into a square shaft 52, and is fitted into the square through hole 42 of the input shaft 41 so as to be able to slide and rotate integrally with the input shaft 41, and the outer peripheral portion of the other end is formed into a spiral with a large lead angle. A thread 53 is formed, and a portion of the spiral thread 53 is slidably fitted into the through hole 47 of the output shaft 46 .

As shown in FIGS. 1 and 10, a portion is cut out approximately at the center of the output shaft 46, and a rod 5 is inserted into the cutout portion 48.
The rod 51 is rotatable in a plane including the axis of the rod 51.
A gear 55 having teeth that mesh with the spiral thread 53 is supported, and a part of the gear is exposed outside the output shaft 46 .

As shown in FIGS. 1 and 6, a sleeve 57 pressed to the left by a spring 59 and a ring-shaped conical cam 56 are slidably fitted to the outer circumference of the approximately central portion of the output shaft 46. The gear 5 has a notch 58 wide enough to allow the gear 55 to rotate freely in a part of its cylindrical portion, and protrudes from the output shaft 46.
5 intrusion is allowed.

A threaded stopper 30 for regulating the forward end of the rod 51 is screwed onto the tip of the output shaft 46.

The rod 51, gear 55, conical cam 56 and sleeve 57 constitute the rod moving device 5.

As shown in FIGS. 1 and 8, the outer periphery of the tip end of the output part case 31 is formed into a small diameter spline cylinder shaft 32,
A cylindrical reaction force receiver 6 having a spline shaft hole 61 is fitted into the spline cylinder shaft 32 with some play.

Further, a torsion spring 33 is disposed between the reaction force receiver 6 and the output part case 31, and in this embodiment, the power part 1
The reaction force receiver 6 is rotationally biased in the counterclockwise direction when viewed from the side, and the side surfaces of the peaks and troughs of the splines to which the reaction force receiver 6 and the output part case 31 are fitted are brought into contact and stopped. A through hole 34 is provided in the valley of the spline cylinder shaft 32 of the output part case 31, and the ball 3
5 is arranged, and the ball 35 is connected to the spring 59.
The conical cam surface of the conical cam 56 is pushed radially outward from the through hole 34, but it stops against the inner surface of the spline shaft hole 61 of the reaction force receiver 6 ( Figure 8).

The tip of the reaction force receiver 6 has a protrusion 60 for receiving reaction force.
is provided, and when the nut is tightened, the protrusion 60 hits an adjacent nut or member and receives a reaction force.

The output part case 31, the spring 33, the reaction force receiver 6,
A control device 9 is configured to operate the detection rod moving device 5 when a load is applied to the output shaft 46 by the ball 35, the spring 59, and the cam 56.

(Operation explanation) Next, each operation when tightening the nut will be explained.

Before use, the first switch 15 is the spring 1
9, the trigger 26 is pressed to the left to open the circuit, and the clutch 2 is in the disconnected state.
The toggle 25 is also pushed to the left by the spring 19 of the second switch 16.

The first and second switches 15 and 16 are electrical contacts that open and close electricity to the electric motor 13. Before operation, the second switch 16 is closed, but the first switch 15 is open, and the electric motor 13 is turned on and off. is not energized and is stopped.

To actually tighten a nut, first temporarily tighten the bolt to 5 to 10% of its proof strength.

Fit the socket 7 into the temporarily tightened nut.

At this time, the protrusion 60 of the reaction force receiver 6 does not touch any adjacent member or nut, and there is play in the fitting between the socket 7 and the nut.

Next, when the trigger 26 is pulled to the right as shown in FIG. 2, the clutch 2 becomes in the transmission state, the first switch 15 is closed, and the electric motor 13 is started.

As a result, the input shaft 41 starts to rotate clockwise when viewed from the electric motor 13 side, but since the output case 31 is not receiving any reaction force, the output case 31 and the reaction force receiver 6 are rotated clockwise when viewed from the input shaft 41 side. It starts spinning counterclockwise and socket 7 does not rotate.

Also, since the rod 51 rotates together with the input shaft 41, the gear 55 meshing with the left-handed helical strip 53 on the outer periphery of the rod 51 changes depending on the relative rotation angle with the output shaft 46, just like a worm wheel. Rotate. The output part case 31 continues to idle together with the reaction force receiver 6, and finally the protrusion 60 of the reaction force receiver 6 hits the adjacent nut _N1 , and the play in the fitting between the nut N and the socket 7 disappears, and the reaction force receiver 6 stops. However, since the output case 31 tries to continue rotating, the torsion spring 33 is twisted, and the peaks and valleys of the spline shaft hole 61 and the spline cylinder shaft 32, into which the output case 31 and the reaction force receiver 6 are fitted, are fitted. It rotates further by the amount of play in the match.

At this time, as shown in FIG. 8, the ball 35 that had been stopped against the inner surface of the spline shaft hole 63 of the reaction force receiver 6 is now able to move outward, and the conical cam 56 that was pushing the ball 35 and the sleeve 57 begins to move forward due to the bias of the spring 59, and the second
As shown in FIG. 6, the end 58a of the notch 58 of the cylindrical portion of the sleeve 57 is engaged with the gear of the gear 55, and the rotation of the gear 55 is stopped.

At the same time, the sides of the peaks and valleys of the splines of the reaction force receiver 6, the spline shaft hole 61, and the spline cylinder shaft 32 of the output case 31 come into contact, the output case 31 receives a reaction force, and the output shaft 46 begins to rotate. Tighten the nut. Since the rotation speed of the input shaft 41 of the planetary gear reduction mechanism 4 is higher than the rotation speed of the output shaft 46, both shafts 4
1 and 46 are in a relatively rotating state.

Therefore, depending on the relative rotation angle between the input shaft 41 and the output shaft 46, the rod 51 meshing with the gear 55 moves toward the power unit 1 while compressing the spring 54, as if pulling a screw out of a screw hole. 3. Press the toggle 25 as shown in Figure 3. This will cause toggle 25
is disengaged from the cam 27 of the trigger 26, shutting off the clutch 2, and at the same time, the second switch 16 opens and the power to the electric motor 13 is also cut off.

At this point, the input shaft 41 stops rotating and the output shaft 46 stops rotating so that no output is produced, completing the tightening of the nut. In addition, the output part case 31 is no longer subjected to reaction force and is rotated to the initial state by the torsion spring 33, so that the ball 35 is pushed against the inner surface of the spline shaft hole 61 of the reaction force receiver 6, as shown in FIGS. 4 and 8. is pushed down toward the axis by

As the ball 35 is pushed down toward the axis, the conical cam 56 and the sleeve 57 move toward the power unit 1 side while compressing the spring 59, and the sleeve 57
The end 58a of the notch 58 and the gear 55 are disengaged, and the gear 55 can rotate freely. This makes it possible for the rod 51 meshing with the gear 55 to move in the axial direction, and moves toward the socket 7 while rotating the gear 55 due to the drag force of the spring 54, and returns to the initial position as shown in FIG. Return to position.

Next, when the trigger 26 is returned to the left, the first switch 15 opens, and the spring 1 of the second switch 16 opens.
9, and the toggle 25 is returned to its initial position, returning to the state shown in FIG.

As described above, each operation when tightening the nut has been explained, from the state in which the rod 51 hits the toggle 25 to disconnect the clutch 2 as shown in Fig. 3, to the state shown in Fig. 5. Since the process from when the rod 51 moves to the left to return to its initial state is instantaneous, the operation to return the trigger 26 to the left comes after this, but in some cases it may be operated during the process. Conceivable. At this time, two operations proceed simultaneously.

The rotation angle of the nut N is set by changing the moving distance of the rod 51. That is, by changing the initial position of the rod 51 depending on the screwing position of the threaded shaft-shaped stopper 30 as shown in FIG.
This is done by changing the distance from when the rod 51 starts moving until it operates the clutch 2, and the amount of movement of the rod 51 is determined by the product of the relative rotation angle between the output shaft 46 and the input shaft 41 and the lead of the spiral strip 53 of the rod 51. Since it is proportional to the rotation angle of the nut, the stopper 30
It can be seen that it can be set by

Although this embodiment describes the case where only one stage of the planetary gear reduction mechanism is used, the present invention is not limited to this.
The relative rotation angle between the first stage input shaft and the final stage output shaft can also be configured without any inconvenience. Furthermore, by replacing the first and second switches 15 and 16 with valves, it is possible to adapt the system to pneumatic or hydraulic motors.

The present invention is not limited to the configuration of the above embodiments, and various modifications are possible within the scope of the claims.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the fastener before tightening, Figure 2
The figure is a cross-sectional view of the fastener during tightening, Figure 3 is a cross-sectional view of the fastener after tightening, and Figure 4 is a cross-sectional view of the fastener with the gear and sleeve disengaged. , Fig. 5 is a sectional view of the rod returned to its original position, Fig. 6 is a sectional view showing the engaged state of the gear and sleeve, Fig. 7 is an explanatory diagram of the reaction force receiver and idling, and Fig. 8 is Figure 1-
9 is a sectional view taken along the line of FIG. 2, FIG. 10 is a sectional view taken along the line of FIG. 1, and FIG. 11 is a sectional view taken along the line XI-XI of FIG. FIG. 12 is an explanatory diagram of a conventional example. DESCRIPTION OF SYMBOLS 1... Power part, 2... Clutch, 28... Clutch cutoff part, 3... Output part, 4... Planetary gear reduction mechanism, 5... Rod moving device, 6... Reaction force receiver, 9
……Control device.

Claims (1)

[Claims] 1. A socket drive mechanism 71 that drives the socket 7 via the clutch 2 and the planetary gear mechanism 4 to a rotational drive device such as an electric motor 13, and the input shaft 41 and output shaft 46 of the planetary gear reduction mechanism 4.
The detection rod 51 is slidably fitted into the axis of the
and the output shaft 46 and input shaft 41 of the planetary gear reduction mechanism 4
a rod moving device 5 that moves the detection rod 51 in the axial direction according to the relative rotation angle of the rod; and a control device 9 that operates the detection rod moving device 5 when a nut tightening load is applied to the output shaft 46.
, a clutch disconnection device 28 that disconnects the clutch 2 when the detection rod moves backward; a reaction force receiver 6 that receives a tightening reaction force when tightening a bolt/nut; and a reaction force receiver 6 that is rotatably attached to the reaction force receiver 6. The detection rod 51 is fitted into the input shaft 41 so as to be able to rotate integrally with the shaft, and the detection rod 51 is fitted into the input shaft 41 so as to be rotatable therewith.
A spiral thread 53 is formed on the portion that is fitted into the output shaft 46 so that it can rotate freely regardless of the rotation of the detection rod 6 . A gear 55 that is rotatably supported in a plane including the axis of the shaft 46, meshes with the spiral thread 53 of the detection rod 51, and has a portion protruding outside the output shaft 46, and the output shaft 46. The gear 55 is slidably fitted in the axial direction and engages with the teeth of the gear 55.
The control device 9 consists of a sleeve 57 having a stop portion 58a that prevents rotation of the planetary gear reduction mechanism 4, and a spring 59 that biases the sleeve 57 in a direction in which the sleeve 57 engages with the gear 55. teeth 40
and a spring 33 that is spline engaged with the case 31 with play in the rotational direction.
The reaction force receiver 6 is biased in the play direction by
Play space 36 between the spline engagement portion of 1 and the reaction force receiver 6
A ball 35 that can be retracted and retracted is disposed so as to be able to slide in the axial direction integrally with the sleeve 57 of the detection rod moving device 5, and is biased by a spring 59 in a direction to press the ball 35 toward the play space 36. Cam 5
A bolt/nut fastener consisting of 6.