JPH05337754A - Bolt angle position detection method arranged around the work axis - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a hub bolt angular position detecting method used for a tire automatic assembly device in a vehicle assembly line, in which the hub bolt and other bolt angular positions can be detected without interference between the bolt and the sensor. An object of the present invention is to provide a bolt angle position detection method that enables accurate rotation angle measurement. [Structure] After aligning the work axis with the rotation axis of the rotation angle sensor, bring the rotation angle sensor close to the bolt mounting surface side of the work, and rotate the rotation angle sensor a predetermined angle from a preset measurement start reference point. When determining the rotation angle of the bolt by moving it, a plurality of measurement start reference points are prepared, and one measurement start reference based on the approximate angular position of the bolt previously grasped by means different from the rotation angle sensor. Select a point,
It is characterized in that the rotation angle sensor is rotated by a predetermined angle from the selected measurement start reference point to obtain the rotation angle of the bolt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt angle position detecting method arranged around a work axis, and more particularly to a hub bolt angle position detecting method used in a tire automatic assembling apparatus in a vehicle assembly line.

[0002]

2. Description of the Related Art Conventionally, a vehicle assembly line, for example, a tire assembling work, is generally constructed so as to be automatically assembled by a tire automatic assembling apparatus such as a robot from the viewpoint of a work environment and a burden on an employee. However, since the wheels of the vehicle that are conveyed onto the assembly line by using a conveyor or the like have a pre-assigned inclination such as "toe" or "caster", the wheel hub attached to the wheels is also In accordance with this, it is inclined by a predetermined angle. Therefore, when the tire supported on the arm of the tire assembling robot is mounted on the wheel hub, the inclination of the wheel hub is measured, and the inclination of the wheel of the tire supported by the robot is matched with the inclination of the wheel hub according to the measurement result. After that, in order to further mount the tire on the wheel hub, it is necessary to match the bolt position of the wheel hub with the bolt insertion hole of the tire wheel.

As the measuring means, the present inventor first described, as described in Japanese Patent Application No. 1-36382, first, for example, a lower arm of a suspension of a wheel, a predetermined height preset by a receiver, more specifically, In this case, the lower arm is pushed up until the camber angle of the wheel hub becomes perpendicular to the horizontal plane. Then, the measuring unit of the robot body is moved to the facing position of the wheel hub, and as shown in FIGS. 6 and 7, a pair of sensors 22 for measuring the toe angle are brought into contact with the end faces of the hub to extend the two sensors. The inclination of the hub surface is measured based on the amount difference. (See FIG. 6 (A)) After this tow angle measurement, the bolt width measurement plates 23 disposed on the left and right three surfaces are removed by removing the lower surfaces so that they can be moved in the center direction by angular displacement of 90 ° each, and the wheel hub 25 By moving each plate 23 toward the center of each plate and bringing it into contact with each hub bolt 26, the moving displacement amount of each plate 23 is measured by the linear gauge 29, and the center of the hub is indexed based on the displacement amount. (See FIG. 6B) Next, the robot body 10 is moved to a position where the axis of the measuring unit 21 of the robot body 10, in other words, the rotation axis of the absolute encoder 31 matches the center of the indexed wheel hub 25. After moving the encoder 31
The rotation angle sensor 24 in the form of a cantilever arm attached to the tip of the rotary shaft 32 is set to a predetermined measurement start reference point S1.
The rotation angle (angular position) from the initial position is detected by rotating in a predetermined direction (counterclockwise in this case) from (hereinafter referred to as the initial position). (See FIG. 6C)

[0004]

However, according to the above-mentioned device, the rotation angle sensor 24 is initialized after the rotation angle sensor 24 is brought close to the wheel hub 25 side to the position where it is engaged with the hub bolt 26 by its rotation. Since the hub bolt 26 is located at a position corresponding to the initial position of the rotation angle sensor 24 because the hub bolt 26 is rotated by a predetermined angle to obtain the angular position of the hub bolt 26, the hub bolt 26 is extended by the extension of the rotation angle sensor 24. 26, in other words, the bolt and the sensor interfere with each other, making it impossible to measure the rotation angle.

Further, since the rotation angle sensor 24 can easily set the initial position, it is generally a rotary actuator 33.
The actuator 33 is configured to be rotatable by a predetermined angle, but when configured in this manner, the actuator 33 is rotated when the rotation angle sensor 24 is rotated from the initial position to the hub bolt 26 side.
In some cases, the side surface of the sensor 24 abuts on the hub bolt 26 due to the fluid pressure applied to the hub bolt 26, and as a result, the hub bolt 26 slightly rotates, so that the rotation angle cannot be accurately measured.

In view of the above-mentioned drawbacks of the prior art, the present invention provides a bolt angle position detecting method capable of accurately measuring a rotation angle of a hub bolt or other bolt angle position without causing interference between the bolt and the sensor. To aim. Another object of the present invention is to detect a rotation angle using the rotary actuator, avoiding collision of the side surface of the sensor with a hub bolt as much as possible, and enabling accurate rotation angle measurement. The purpose is to provide.

[0007]

A first aspect of the present invention is directed to avoiding interference between the bolt and the sensor. The work axis is aligned with the rotation axis of the rotation angle sensor, and then the rotation is performed. In the bolt angle position detection method of determining the rotation angle of the bolt by rotating the rotation angle sensor by a predetermined angle from a preset measurement start reference point by bringing the angle sensor close to the bolt mounting surface side of the workpiece, the measurement start A plurality of reference points are prepared, and one measurement start reference point is selected based on the approximate angular position of the bolt previously grasped by means different from the rotation angle sensor, and the rotation angle is selected from the selected measurement start reference points. It is characterized in that the rotation angle of the bolt is obtained by rotating the sensor by a predetermined angle. In addition, the measurement start reference point S1,
As a matter of course, S2 is selected so that interference between the bolt and the sensor does not occur.

Therefore, the present invention is applicable not only to the angular position of the hub bolt but also to any device as long as it detects the angular position of the bolts arranged around the work axis. Further, in order to grasp the approximate angular position of the bolt by means different from the rotation angle sensor, for example, as shown in FIG.
And, as shown in FIG. 7, a means for indexing the center of the wheel hub is used to obtain a facing distance (2α) between a pair of hub bolt rows facing each other with the center interposed therebetween. Since (2β) is already known, for example, when the first measurement start reference point S1 is set on the vertical line, Cos (θ) = α /
The approximate rotation angle of the bolt from the measurement start reference point S1 can be easily obtained by β, and therefore the approximate angular position can be measured simultaneously with the work center indexing and by the same measuring means. Does not become complicated. In addition, it is natural that the measurement start reference points S1 and S2 are selected so that interference between the bolt and the sensor does not occur.

According to a second aspect of the present invention, when the rotation angle sensor is configured to be rotatable by a rotary actuator at a predetermined angle, the rotary actuator is directed in a direction opposite to the rotation direction of the rotation angle sensor. It is characterized in that the rotation angle sensor is rotated while always applying back pressure.

[0010]

According to the first aspect of the present invention, since the measurement start reference point can always be set in a direction in which the bolt and the sensor do not interfere with each other, there is no possibility that the bolt and the sensor interfere with each other, and the hub bolt is completely eliminated. Accurate rotation angle measurement of other bolt angle position is possible.

According to the second aspect of the present invention, even if the rotation angle is measured using the rotary actuator,
Since the rotary angle sensor is rotated while always applying a back pressure to the rotary actuator in the direction opposite to the rotation direction of the rotation angle sensor, the contact pressure to the hub bolt on the side surface of the sensor is greatly increased. Therefore, it is possible to prevent a slight rotation of the hub bolt 26 due to the collision, which enables accurate measurement of the rotation angle.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described in detail below as an example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Not too much. Figure 8
Shows an overall structure of a robot to which the present invention is applied. The robot body 10 is supported by an L-shaped support member 12 so as to be vertically movable by a drive motor 17Z, and the support member 12 is driven. The motor 17S is rotatably attached to the support base 13 about the vertical axis 13a, and the support base 13 is rotatable.
Is supported by the base 14 so as to be horizontally movable in the Y-axis direction by the drive motor 17Y, and the base 14 is supported by the base 11 in the X-axis direction by the drive motor 17X. 10 can be moved freely in the X, Y, Z, and S directions.

A tire holding portion 20 and a measuring portion 21 are attached at 180 ° symmetrical positions on both front and back sides of the robot body 10, and the tire holding portion 20 has an arm 20a for positioning and holding the tire and the tire. Hub bolt 26
It is equipped with four nut runners 20b for tightening. The measuring unit 21 includes the pair of sensors 22 for measuring the toe angle, the bolt width measuring plate 23, and the rotation angle sensor 24.

Next, the structure around the rotation angle sensor 24, which is a main part of the embodiment of the measuring unit 21, will be described with reference to FIGS.
It will be explained based on. In FIG. 3, reference numeral 31 is an absolute encoder, the shaft end of which is connected via a coupling 41 to a rotary shaft 32 extending toward the wheel hub 25. The rotation shaft 32 has an inverted L-shaped rotation angle sensor 24 fixed to the free end side of the rotation shaft 32 via an angle regulation arm 42. 33 is a predetermined angle range (90 ° or more) from the return position
The rotary actuator is configured to be swingable, and is connected to the rotary shaft 32 via a gear 43. The rotation angle sensor 24 is set to be displaced by about 45 ° to the left from vertically upward at the return position S2 of the actuator 33 as shown by the imaginary line in FIG. Reference numeral 39 denotes a wheel hub rotation stopper 39 attached to the lower end side of a support plate 38 that supports the rotating shaft 32.
A rubber 392 is attached to the tip of a shaft 391 that moves forward and backward with respect to the hole hub via a bearing 381 on the lower end side of the shaft 8, and a spring 393 is interposed between the tip and the bearing 381 to elastically end the tip of the stopper 39. Is configured to be able to press the disk surface 27 of the wheel hub 25.

Further, as shown in FIG. 4, a fluid cylinder 37 is attached to the side of the support plate 38 so as to be able to engage with the angle regulating arm 42 by the extension of the rod 371. By engaging with 42, the rotation angle sensor 24 is positioned at the vertically upper position S1 as shown by the solid line in FIG. 2 without returning to the return position. In order to accurately position the rotation angle sensor 24 at the vertically upper position S1 without returning to the return position S2, a predetermined pressure is applied to the rotation angle sensor 24 in the return direction (counterclockwise direction) to the return position S2. It is preferable to apply back pressure. And each of the members is a support plate 3
It is integrally attached to the delivery cylinder 36 via 8 and is configured to be movable in the contacting / separating direction of the wheel hub 25 by the forward / backward movement of the cylinder 36.

FIG. 5 is an air circuit diagram of the rotary actuator 33. The actuator 33 has a positive pressure port 33a and a back pressure port 33b as is well known, and the forward pressure port 33a side has a raw air circuit 51 in order. A solenoid valve 52, a regulator 53, a throttle valve 54 (flow rate controller) are interposed, and the solenoid 52 is turned ON / O.
The air pressure controlled to ³ Kgf / cm ² by the FF operation can be supplied to the forward pressure port 33a at a predetermined flow rate. On the side of the back pressure port 33b, the original air circuit is connected to the back pressure port via a relief valve 55, which allows air pressure to escape when the pressure exceeds a certain level, and a regulator valve 57 that is maintained at a predetermined pressure by a regulator valve 56. For example, the air pressure controlled to ² kgf / cm ² can be supplied to the back pressure port 33b.

Next, examples of the present invention will be described. 58
Is a silencer, and 59 is a blind lid. First, the rod of the fluid cylinder 37 is extended and engaged with the angle regulating arm 42, and the rotation angle sensor 24 is positioned at the vertically upper position S1 shown by the solid line in FIG. The rotary actuator 33 always applies a back pressure controlled to ² Kgf / cm ² , and the actuator 33 returns to the return position S.
Force in two directions. The feed cylinder is retracted to the initial position, so that the rotation angle sensor 24 and the wheel hub 25 rotation stopper 39 are retracted from the wheel hub 25 surface or the disk surface 27.

In this state, as described in the section of the prior art, after the pair of sensors 22 for measuring the toe angle are brought into contact with the hub end face and the toe angle is measured based on the difference in the amount of extension between the two sensors 22, By moving the bolt width measuring plates 23 arranged on the upper, right and left three surfaces respectively toward the center of the wheel hub 25 and abutting on the respective hub bolts 26, the moving displacement amount of each plate 23 is measured by the linear gauge 27. And measure the center of the hub based on the displacement,
The facing distance (2α) between the pair of hub bolts 26 facing each other across the center is determined. On the other hand, since the pitch PCD (2β) between the hub bolts 26 passing through the center of the wheel hub 25 is known, the approximate rotation angle of the hub bolt 26 can be obtained based on the equation α / β = Cos (θ).

For example, in the case of the wheel hubs 25 having PCDs of 114.3 mm and 100 mm, the above θ
Hub bolt 2 when θ ≦ 15 ° and θ ≦ 17 °, respectively
It has been confirmed by experiments or design drawings that the sensor 6 and the sensor interfere with each other.
As shown in (A), α / β = Cos (θ) is θ ≦ 1.
In the case of 5 ° or θ ≦ 17 °, the fluid cylinder 37 engaged with the angle regulating arm 42 is retracted to the return position, while the rotary actuator 33 is always backed as shown in FIG. 1 (B). Since the pressure is applied, it returns to the return position S2, which causes the rotation angle sensor 24 to rotate to the left by about 45 ° from the vertically upper side. (This rotation angle is measured by the absolute type encoder 31 and is set to R.) As a result, there is no risk of the hub bolt 26 and the sensor interfering with each other. Therefore, the feed cylinder is extended and the rotation angle sensor 24 is attached to the wheel hub 25 surface. Close to the side. At the same time, the wheel hub 25 detent stopper 39 also follows this and moves to the disk surface 27 side.
Elastically using the rubber 392 at the tip of the stopper 39 to press the wheel hub 25 through the disc surface 27.
Hold the position of.

In this state, the rotary actuator 3
3Kgf / cm by turning on the solenoid 52 of 3
^The air pressure controlled by ² is applied to the actuator 33 at a predetermined flow velocity, and the rotation angle sensor 24 is rotated clockwise through the rotation shaft 32 until it comes into contact with the hub bolt 26. Lute type encoder 31
And measure the rotation angle γ ₁ . (In this case, when converted to the rotation angle from the vertically upper position S1, {γ ₁ -L}
Becomes At this time, since a back pressure of ² kgf / cm ² is constantly applied to the rotary actuator 33, the contact pressure of the side surface of the sensor with the hub bolt 26 is substantially 1.
Since the pressure is as low as Kgf / cm ² , it is possible to prevent a slight rotation of the hub bolt 26 due to the collision, and the wheel hub 25 detent stopper 39.
This enables accurate measurement of the rotation angle in combination with the position holding effect.

On the other hand, α / β = Cos (θ) is θ ≧ 15
° (PCD114.3) or θ ≧ 17 ° (PCD1
In the case of (00), the fluid cylinder 37 engaged with the angle regulating arm 42 is left as it is, and the delivery cylinder 36 is extended so that the rotation angle sensor 24 faces the wheel hub 25 surface and the wheel hub rotation stopper. 39 is moved to the disk surface 27 side, and the rotation angle is measured in the same manner as described above.

[0022]

As is clear from the description of the embodiment, according to the present invention, the plurality of measurement start reference points S1 and S2 can be selected so that the bolt and the sensor do not interfere with each other. Since there is no risk of interference, it is possible to measure the rotation angle of the hub bolt and other bolt angle positions with high accuracy. Further, according to the present invention, since the back pressure is constantly applied to the rotary actuator in the direction opposite to the rotation direction of the rotation angle sensor, it is possible to greatly reduce the contact pressure of the side surface of the sensor with the hub bolt. Therefore, it is possible to prevent a slight rotation of the hub bolt due to the collision, and it is possible to accurately measure the rotation angle. And so on.

[Brief description of drawings]

FIG. 1 shows a basic configuration of the present invention, where (A) is an area where a hub bolt and a sensor interfere with each other, (B) is a case where a second measurement start reference point is selected when interference occurs, and (C) shows The rotation angle measuring method in the case of selecting the first measurement start reference point as it is will be described.

FIG. 2 is a right side view showing the periphery of the angle sensor of the measuring unit according to the embodiment of the present invention.

FIG. 3 is a front view of FIG.

FIG. 4 is a plan view of an essential part of FIG.

FIG. 5 is an air piping diagram of a rotary air actuator.

FIG. 6 shows a measurement procedure required when mounting a tire on a hub bolt to which the present invention is applied.

FIG. 7 is an operation explanatory view showing a measuring portion of a hub bolt according to a conventional technique.

FIG. 8 is an external view of a robot body to which the present invention is applied.

[Explanation of symbols]

 S1, S2 Measurement start reference point 24 Rotation angle sensor 25 Wheel hub 26 Hub bolt 27 Disk surface 31 Absolute encoder 33 Rotary actuator 42 Angle regulation arm

Claims (2)

[Claims] 1. After the work shaft center and the rotation shaft of the rotation angle sensor are aligned with each other, the rotation angle sensor is brought close to the bolt mounting surface side of the work, and the rotation angle sensor is set to a predetermined value from a preset measurement start reference point. In the bolt angle position detection method for obtaining the rotation angle of the bolt by rotating the angle, a plurality of the measurement start reference points are prepared, and based on the approximate angular position of the bolt previously grasped by means different from the rotation angle sensor. One of the measurement start reference points is selected, and the rotation angle sensor is rotated by a predetermined angle from the selected measurement start reference point to obtain the rotation angle of the bolt. Bolt angle position detection method 2. The bolt angle position detecting method according to claim 1, wherein the rotation angle sensor can be rotated by a predetermined angle using a rotary actuator, and the rotary actuator has a direction opposite to the rotation direction of the rotation angle sensor. Angle detection method arranged around the work shaft center, wherein the rotation angle sensor is rotated while always applying back pressure to