JPH087042B2 - Bolt position detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a bolt position detecting device that detects an accurate position of a bolt or the like for mounting a tire by two or more sets of sensors.

[Prior Art] As a conventional technology, for example, one in which the position of a bolt is detected by a reflective sensor is known.

This is to detect the position of the bolt by measuring the distance from a reflection type sensor arranged outside the side portion of the bolt to the side surface of the bolt. However, in the conventional technique of this type, in a bolt having a thread groove, that is, in a bolt having a peak portion and a valley portion, the measured value varies depending on the end surface shape of the bolt, and as a result, the position of the bolt is accurately determined. It was difficult to detect. Therefore, for example, when the bolt is a hub bolt of a hub that constitutes a wheel of an automobile, there is a disadvantage that the hub bolt cannot be automatically and surely inserted into the hole of the wheel on which the tire is mounted. Further, since it is a reflection type sensor, there is a defect that the distance to anything other than the bolt is measured.

Therefore, at present, the position of the bolt is detected using a pair of transmission type sensors, one for transmission and the other for reception.
That is, when the bolt passes between the transmitting sensor and the receiving sensor, the interrupted time is measured, the position of the axis line that is the center of the bolt is calculated, and the position of the bolt is detected. .

[Problem to be Solved by the Invention] However, in the above-described configuration, like a hub bolt for mounting a tire, when the bolt has a mountain portion and a valley portion to form a thread groove, As shown in the figure, the axis 8a of the bolt 2 calculated by first hitting the peak 6a of the bolt 2 with the optical axis 4 of the sensor is
There is a problem in that the detection is centered on a position deviated by Δ ₁ from the actual axis 8 of the bolt 2 to the mountain portion 6a side. This is because the mountain portion 6a is protruding. On the other hand, when the optical axis 4 of the sensor first hits the valley 6b, the bolt 2
When the center of is detected, the position shifted from the actual axis 8 of the bolt 2 by Δ ₂ on the opposite side to Δ ₁ is detected as the axis 8b. This is because the valley 6b is recessed.

Thus, when the axis of the bolt 2 is detected with a deviation of Δ ₁ or Δ ₂ from the actual position, the detected bolt 2
The position of the tire is determined according to the position of the
_The presence of the deviation of ₁ or Δ ₂ causes the tire to impactly contact the bolt or the like, which makes it substantially difficult to mount the tire itself. Therefore, there have been problems such as a decrease in production efficiency as a whole work process or a damage of tires or the like, which directly leads to a decrease in product quality.

The present invention has been made to solve the above problems, and it is possible to detect the position of a bolt extremely accurately, facilitate the mounting of parts and the like, and ensure excellent product quality. An object is to provide a bolt position detecting device.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a device for detecting the positions of bolts in which screw grooves are engraved at equal pitches. Arranging at least two sets of sensors extending in the direction
The height difference between the sensing part of one pair of sensors and the sensing part of the other pair of sensors is set to P × (n + 1/2), where P is the pitch of the thread groove of the bolt. Characterize.

[Operation] When the sensor arm to which the sensor is attached rotates, the bolt passes between at least two sets of sensors. that time,
When the pitch of the thread groove of the bolt between one pair of sensors and the other pair of sensors is P, P × (n + 1/2)
Due to the step difference, the Δ ₁ and Δ ₂ cancel each other out, so that the axial position of the bolt can be accurately detected. That is, thereafter, the axis of the bolt is obtained by the respective sensors, and its accurate position is detected.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a bolt position detecting device 10 as a first embodiment for detecting the position of a hub bolt protruding from a hub.
It is a schematic side view explanatory drawing.

The hub 12 has four hub bolts 14 arranged at equal intervals in the vicinity of the outer peripheral portion of the hub 12 and is mounted on the vehicle body side. The hub bolt 14 is provided with a thread groove having a pitch P at equal intervals on its surface.

Therefore, the bolt position detection device 10, the holding portion 16,
The rotation drive unit 18 and the detection unit 20 are basically configured.

The holding portion 16 has a pushing stopper 22 for being pushed by the hub 12 at the tip portion, and a rotary shaft 24 that engages with the pushing stopper 22 via a bearing 23 on one end side, A bearing 25 is provided at the other end of the rotary shaft 24 to support the rotary shaft 24. A holder 26 is fitted into the bearing 25, and the holder 26 has a bush shape and one surface thereof is a flat portion 28. Further, a cylinder rod 32 of a cylinder 30 as a linear actuator is connected to the holder 26. As is easily understood from FIG. 1, a connecting member 33 is actually fixed to the tip end of the cylinder rod 32, and the freezing member 33 is fixed to one surface of the holder 26.

Next, the rotary drive source 36 is fixed to the flat portion 28 of the holder 26. A first gear 34 is axially supported on a drive shaft 38 of the rotary drive source 36, and the first gear 34 is a second gear fitted to the rotary shaft 24.
Mesh with the gear 35 of the. The rotary drive source 36 is connected to an encoder 40 for detecting its rotation angle.

Further, a sensor arm 42 that constitutes the detection unit 20 is fixed to the rotary shaft 24, and one pair of optical sensors 44a and 44b and another pair of optical sensors 46a and 46b are provided on the sensor arm 42. ing.

 Details of the detection unit 20 are shown in FIGS.

The sensor arms 42 extend on both sides of the rotary shaft 24 in the radial direction about the central axis, and are arranged on one axis in the present embodiment. That is, the rotary shaft 24
One pair of photosensors 44a and 44b is arranged on one side of the pair, and one pair of photosensors 46a and 46b is arranged on the other side. The hub bolt 14 is arranged so as to cross between the optical sensors 44a, 44b, 46a, 46b. The optical sensors 44a and 46a include
Light emitting portions 48, 48 for irradiating light are formed, and the light sensors 44b, 46b have a light receiving portion for receiving the light.
50, 50 are formed. That is, the light emitting unit 48, 48
Light radiated from the light source reaches the light receiving units 50, 50 and is received by the light receiving units. The optical axis of the light is shown in FIG. 3 by reference numerals 52a and 52b. Further, the light emitting unit 48 of the optical sensor 44a, the light receiving unit 50 of the optical sensor 44b, and the light emitting unit 48 of the optical sensor 46a,
The light receiving section 50 of the optical sensor 46b is the optical axis 52a and the optical axis 52a.
It is arranged so that the height difference d from b is set to P × (n + 1/2) when the pitch of the thread groove of the hub bolt 14 is P. That is, the optical axis 52a is the hub bolt 1
The optical axis 52b is arranged so as to abut the valley portion 56b of the spiral groove when hitting the crest portion 56a of the four spiral groove.

On the other hand, the rotation angle of the rotary drive source 36 obtained by the encoder 40, the rotation speed of the sensor arm 42,
An arithmetic circuit (not shown) for signal processing the optical axis 52a and the time when the optical axis 52b is interrupted by the hub bolt 14 is provided, and the arithmetic circuit can calculate the accurate position of the axis 54 of the hub bolt 14. it can.

The bolt position detecting device according to the present embodiment is basically constructed as described above, and its operation will be described below.

According to the apparatus configured as described above, first, the cylinder
30 is operated to extend the cylinder rod 32 in the direction of the arrow A, and the stopper 12 is pressed against the hub 12 while the rotary shaft 24 is displaced.
Abut and hold. Next, by driving the rotary drive source 36, the first gear 34 rotates in the direction of arrow B, whereby the second gear 35 starts rotating in the direction opposite to the direction of the first gear 34. With this rotation, the rotary shaft 24 rotates,
The sensor arm 42 held by 24 will rotate as well. At this time, the smooth rotation of the rotary shaft 24 is ensured by the bearings 23, 25.
Secured by As a result, the light from the light emitting parts 48, 48 tries to reach the light receiving parts 50, 50 side.
The existence of 4 and 14 makes this achievement difficult. On the other hand, the rotation angle of the rotary drive source 36 is detected by the encoder 40.
Then, from the rotation angle of the rotary drive source 36, the rotation speed of the sensor arm 42, and the time when the optical axis 52a and the optical axis 52b are cut off, the optical axis 52a is the peak portion of the hub bolt 14 first. The position of the axis 54a when hitting 56a is detected. Similarly, the optical axis 52b detects the position of the axis 54b when the optical axis 52b first hits the valley portion 56b of the hub bolt 14. These axes 54a, 54b
As explained in the conventional example, the actual
₁ and Δ ₂ are displaced from each other. Here, the Δ ₁ is the side facing the displacement direction of the optical axes 52a and 52b, and the Δ ₂ is the opposite side of the Δ ₁ .

Now, since these errors Δ ₁ and Δ ₂ are almost equal, in order to cancel them, it is possible to obtain the accurate position of the axis line 54 of the hub bolt 14 by calculating as (Δ ₁ + Δ ₂ ) / 2. it can.

Next, as a second embodiment of the present invention, the detection unit 20a is shown in FIGS. The same components as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, when the height difference d of the sensing portion is P, the pitch of the thread groove of the hub bolt 14 is P × (n + 1 /
Two sets of optical sensors 44a, 44b, 46a, 46b set in 2) are attached on one side of the sensor arm 43. The first
Similar to the embodiment, the optical sensors 44a and 46a include light emitting units 48 and 48.
Is formed, and the light receiving portions 50, 50 are formed in the optical sensors 44b, 46b. That is, the sensor arm 43 is
It extends radially from 24 and is located on one axis.

In this embodiment, the sensor arm 43 includes the rotating shaft.
Two sets of optical sensors 44a, 44b, 46a, 4 on one side at the center of 24
Due to the placement of 6b, these optical sensors 44a, 44b, 46
The hub bolt 14 crosses between a and 46b.

Then, the optical sensor 44 is placed inside by interposing the hub bolt 14 when passing between the optical sensors 44a, 44b, 46a, 46b.
Install a and 44b, and attach an optical sensor to the outside
46a and 46b are installed.

In the case of such a configuration, the light emitted from the light emitting portions 48, 48 is transmitted by the hub bolt 14 to the light receiving portions 50, 50.
When the optical axis 52a, 52b received by the optical axis is reached, the optical axes 52a and 52b received by the optical axis are blocked. At this time, the optical axis 52a is first attached to the hub bolt 14
The position of the axis 54a when hitting the crest 56a is detected, and at the same time, the position of the axis 54b when the optical axis 52b first hits the valley 56b of the hub bolt 14 is detected. Moreover, these axis 5
4a and 54b are at positions displaced by Δ ₁ and Δ ₂ from the actual axis 54, respectively. Since these errors Δ ₁ and Δ ₂ are substantially equal to each other, an accurate position of the axis line 54 of the hub bolt 14 can be obtained by calculating as (Δ ₁ + Δ ₂ ) / 2 to cancel them.

In the second embodiment, the sensor arm 42 is provided with two sets of optical sensors 44a, 44 only on one side of the rotary shaft 24.
b, 46a, 46b are installed. Therefore, the optical axes 52a and 52b are simultaneously formed on the peak portion 56a and the valley portion 56b of one hub bolt 14 at a time.
The position of the axis 54 can be detected quickly.

Next, a detection unit 20b as a third embodiment of the present invention is shown in FIGS. The same components as those in the first and second embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

In the present embodiment, as in the first and second embodiments, the height difference d of the sensing portion causes the pitch of the thread groove of the bolt 14 to be P.
Then, two sets of optical sensors 44a, 44b, 46a, 46b set to P × (n + 1/2) are mounted on the sensor arm 45. As in the first and second embodiments, the light emitting portions 48, 48 are formed in the optical sensors 44a, 46a.
Light receiving portions 50 and 50 are formed on b and 46b. The sensor arm 45 has one side extending straight outwardly around the rotary shaft 24, and the other side is gradually widened from the vicinity of the rotary shaft 24 so that the end portion has the widest width, and the outer side is expanded. It is extended so as to face the direction. Further, the optical sensors 44a, 44b and the optical sensors 46a, 46b are installed on the widening side of the sensor arm 45 and are spaced apart from each other by a predetermined interval in the radial direction from the rotary shaft 24. It should be noted that the optical sensor is located inward about the rotary shaft 24.
44a and 46a are attached, and optical sensors 44b and 46b are attached to the outside. That is, when the sensor arm 45 rotates, the optical sensors 44a and 46a and the optical sensors 44b and 46b are configured to rotate on the same circumference.

In the case of such a configuration, the light emitted from the light emitting units 48, 48 by the hub bolt 14 is the light receiving units 50, 50.
The optical axes 52a and 52b that reach and are received by are blocked. Then, the optical axis 52a is first aligned with the peak portion 56a of the hub bolt 14.
The position of the axis 54a when hitting the
Axis 54b when the first hit the valley 56b of the hub bolt 14
Detect the position of. As with the previous embodiment, these axes 54
The positions a and 54b are respectively displaced from the actual axis 54 by Δ ₁ and Δ ₂ . Since these errors Δ ₁ and Δ ₂ are substantially equal to each other, an accurate position of the axis line 54 of the hub bolt 14 can be obtained by calculating as (Δ ₁ + Δ ₂ ) / 2 to cancel them.

In the above configuration, even when the pitch P of the hub bolt 14 is narrow and the light emitting parts 48, 48 and the light receiving parts 50, 50 are close to each other, the respective optical sensors 44a, 44b, 46a, 46b influence each other. It is possible to smoothly perform the detection work without being affected.

Although various embodiments of the present invention have been described above, it goes without saying that a mechanism for absorbing the inclination of the bolt may be added to the device according to the present invention in order to detect a more accurate position.

EFFECTS OF THE INVENTION According to the present invention, when the pitch of the thread groove of the bolt is P, the bolt is passed between two sets of sensors having a height difference of P × (n + 1/2). Therefore, there is no influence of the peaks and valleys of the bolt, and the position of the bolt can be detected extremely accurately. For this reason, positioning when installing the tire is done accurately,
There is an advantage that the quality of the product can be secured by preventing damage to the tire and the like, and that the parts and the like can be easily mounted.

[Brief description of drawings]

FIG. 1 is a schematic side view of a part of a vehicle body and a bolt position detecting device of the present invention, FIG. 2 is an enlarged view of a detecting portion of a first embodiment of FIG. 1 of the present invention, and FIG. FIG. 4a is an enlarged view of an essential part of the second embodiment of the present invention, FIG. 4b is an enlarged side view of the essential part of the second embodiment of the present invention, and FIG. FIG. 5 is an enlarged side view of an essential part of a third embodiment of the present invention, and FIG. 6 is an enlarged schematic view of an essential part of a conventional example. 14 …… Hub bolt 10 …… Bolt position detector 20,20a, 20b …… Detector 24 …… Rotary shaft 42,43,45 …… Sensor arm 44a, 44b, 46a, 46b …… Optical sensor d …… Height Difference n …… Pitch number P …… Pitch

Claims (1)

[Claims] 1. A device for detecting the positions of bolts in which screw grooves are formed at equal pitches, wherein at least two sets of sensors are arranged so as to extend in a radial direction from a central axis of a rotating sensor arm, The height difference between the sensing part of one pair of sensors and the sensing part of the other pair of sensors is set to P × (n + 1/2), where P is the pitch of the thread groove of the bolt. A bolt position detecting device characterized in that