JPH09228778A - Roller bit rotation detector - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a practical roller bit rotation detecting device that can endure long-term use without fear of being damaged by contact with debris or earth and sand water. A cutter unit 9 and an insertion hole 9A of the cutter unit 9
Fixed shaft portion 10 that rotatably supports the cutter portion 9 inserted through the shaft
In the roller bit 4 having the above, the fixed shaft portion 10 is provided with the oil supply passage 20 for supplying pressure oil and the oil discharge passage 21 for discharging the pressure oil, and the cutter portion 9 is provided with the oil supply passage 20 and the oil discharge passage. 21 is provided with a communication passage 22 for communicating with the oil supply passage 2
0 and the oil discharge passage 21 are intermittently communicated with each other through the communication passage 22 in accordance with the rotation of the cutter portion 9 so that the pressure oil of the oil supply passage 20 is discharged.
The pressure sensor 26 and the relief valve 25, which detect the pressure drop of the pressure oil and generate an electric signal, on the upstream side and the downstream side of the supply pipeline 20a that guide the pressure oil to the oil supply passage 20, respectively. The indicator light 27 is provided by an electric signal generated by the pressure sensor 26 when the oil supply passage 20 and the oil discharge passage 21 communicate with each other.
Is blinked to detect the rotating state of the roller bit 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller bit rotation detecting device for detecting whether or not a roller bit is rotating smoothly during excavation of natural ground.
It is useful for shield machine.

[0002]

2. Description of the Related Art When excavating a natural ground with an excavator, normally, a cutter bit that revolves together with a cutter head to scrape the natural ground is used, but the natural ground is a large gravel layer, a bedrock layer, etc. When the ground is hard, a roller bit that revolves with the cutter head and that crushes the gravel layer, rock layer, etc. while rotating by applying thrust is used. Looking at an example of using a shield excavator as an excavator, normally, excavation is performed using a cutter bit that only revolves and cuts the ground, but when it is a stratum where a gravel layer or a rock layer appears. , Such a roller bit is attached to the cutter head, and the excavation proceeds while crushing these by the rotation of the cutter. The roller bit can exert its original function by being self-rotated during the excavation as described above. If the self-rotation cannot be performed smoothly, the roller bit is unevenly worn and further damaged. It will be. If the roller bit cannot rotate smoothly, investigate the cause and lubricate the bearing part with grease or replace the roller bit as necessary. Measures are needed. For example, looking at the work when replacing the roller bit in a shield machine, when trying to replace it, inject a chemical solution as a ground stabilizer into the ground in front of the cutter head of the shield machine to improve the ground. After stabilizing,
It is necessary to make arrangements such as excavating the ground in front of it by hand digging to secure a working space required for the exchanging work. For that purpose, it is necessary not only to arrange replacement parts but also to arrange chemicals and manpower, and it is necessary to proceed with the preparation systematically. The replacement work cannot be carried out smoothly. Further, even when grease is applied to the roller bit, it is important to always grasp the rotational state of the roller bit properly and to perform the grease supply at a proper timing.

From the above, in the roller bit, it is a very important theme to always be able to accurately grasp whether or not the rotation is smoothly performed during excavation.

By the way, in the roller bit which crushes the ground while being applied to the face of the face, it is difficult to accurately grasp the rotating state by visual inspection during excavation. This is virtually impossible with shield machines installed in front of the bulkhead of the structure. Therefore, during excavation of the natural ground, development of a roller bit rotation detection device for detecting whether or not the rotation of the roller bit is smoothly performed is requested,
Conventionally, as the apparatus of this type, the apparatus described in Japanese Utility Model Publication No. Sho 63-171495 and Japanese Utility Model Publication No. Sho 63-171496 has been proposed by the same applicant.

As for the former device, the same device is equipped with a metal piece for rotation detection on the end face of the disk base metal of a roller cutter of a shield machine, which is a type of roller bit, and rotates the disk base metal. A proximity switch is provided on a roller cutter saddle portion, which is a supporting member of a fixed shaft that pivotally supports as much as possible, so as to face the metal piece, and the proximity switch blinks an indicator light. Since this conventional device has such a configuration, when the roller cutter is rotating during excavation of the natural ground, the proximity switch emits a signal each time the metal piece approaches to turn on the indicator light. It blinks in synchronism with the rotation of the roller cutter, and whether or not the roller cutter is rotating smoothly can be detected by the blinking state.

Next, regarding the latter device, the device is provided with a proximity switch so as to be able to face a cemented carbide chip provided on the peripheral surface of the roller cutter of the shield machine, and display is performed by this proximity switch. The light is made to blink. Since this conventional device has such a configuration, when the roller cutter rotates while excavating the natural ground, the proximity switch emits a signal each time the cemented carbide tip approaches to turn on the indicator light. It blinks in synchronization with the rotation of the roller cutter, and it is possible to detect whether or not the roller cutter is rotating smoothly and the wear state of the cemented carbide tip by the blinking state.

[0007]

By the way, since the area around such a roller cutter, that is, the roller bit, is in a bad environment in which debris that has been cut or crushed is scattered and sediment water flows, a proximity switch is used. When a metal piece for detecting rotation and rotation is installed, it is not possible to obtain a practical roller bit rotation detection device that can withstand long-term use if only the convenience of installation and rotation detection is taken into consideration.

However, the above-mentioned Japanese Utility Model Laid-Open No. 63-171495.
In the device described in the publication, the proximity switch and the metal piece for rotation detection face the gap formed between the disk-shaped base metal and the roller cutter saddle part so as to allow the base metal to rotate. There is a risk of damage due to contact with cutting and crushed debris and earth and sand water that enter through the gap. That is, when debris that has been cut or crushed is caught in the gap or sediment water flows in as the roller cutter rotates, the proximity switch or the metal piece for rotation detection is rotated by the debris or sediment water as if it were rotating abrasive. In such a state, the proximity switch is damaged or the metal piece is worn, and it becomes impossible to correctly detect the rotation state of the roller cutter. Further, even if such a thing is omitted, it is a problem in itself to provide a proximity switch as an instrument in the roller cutter saddle part which is impacted by scattering of debris, etc., and it may cause a failure of the proximity switch. .

Further, looking at the device described in Japanese Utility Model Laid-Open No. 63-171496, a proximity switch is provided so as to face a cemented carbide chip which is a crushing means of rock, and the switch is provided with earth and stones. It is apparent that there is a risk of damage due to contact with water. As can be seen from the two devices proposed by the same applicant, the prior art lacks consideration for preventing damage to the roller bit rotation detecting device.

In view of such circumstances, an object of the present invention is to provide a practical roller bit rotation detecting device that solves the problems found in the prior art as described above and can withstand long-term use. To do.

[0011]

The above objects of the present invention are as follows:
"In a roller bit having a cutter portion and a fixed shaft portion that is inserted into the cutter portion and rotatably supports the cutter portion, a fluid supply path for supplying a fluid and a fluid for discharging a fluid to the fixed shaft portion. A discharge passage is provided, and a communication passage for communicating the fluid supply passage and the fluid discharge passage is provided in the cutter portion, and the fluid supply passage and the fluid discharge passage are intermittently formed by the communication passage as the cutter portion rotates. Means for communicating the fluid in the fluid supply passage to the fluid discharge passage, and detecting the fact that the fluid in the fluid supply passage has been introduced to the fluid discharge passage, and issuing a signal for operating the display means. Is provided at a location different from that of the roller bit. "
A roller bit rotation detection device as described in.

Since the roller bit rotation detecting device of the present invention has such a structure, by rotating the roller bit while revolving it and applying a thrust to it,
When hard ground is crushed, the cutter part rotates due to its rotation, and the communication passage provided in the cutter part intermittently connects the fluid supply passage and the fluid discharge passage to fluidize the fluid in the fluid supply passage. Guide to the discharge path. Then, every time the fluid in the fluid supply path is guided to the fluid discharge path, the detection means detects this and outputs a signal for operating the display means. Therefore, when such a signal is emitted regularly, it means that the roller bit is rotating smoothly, and when such a signal is emitted irregularly or whether such a signal is kept emitted or not at all. When it is not emitted, it means that the rotation of the roller bit is not smoothly performed or is not performed at all, so that the rotation state of the roller bit can be detected by the device of the present invention. When the display means is activated by
The rotation state can be discriminated by the operator.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be clarified by describing concrete examples showing how the present invention is actually embodied with reference to FIGS. To do. Each of these figures shows a specific example in which the roller bit rotation detecting device of the present invention is applied to a muddy water shield machine, and FIG. 1 is a side view showing the specific example.
1 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a sectional view taken along the line BB of FIG. 2, FIG. 4 is a sectional view taken along the line CC of FIG. 3, and FIG. 5 is a roller bit of an embodiment of the present invention. FIG. 4 is a hydraulic circuit diagram for explaining the operation of the rotation detection device, (a) showing a state when the oil supply passage and the oil discharge passage are in communication, and (b) showing a state when these oil passages are not in communication. It is a figure. Note that in FIG. 5B, a part of the configuration shown in FIG. 5A, such as the configuration of the shield body 1, the indicator light 27, and the periphery thereof, is omitted.

First, the outline of the construction of the muddy water shield machine will be described. 1 is a shield body, 2 is a radial shape provided in front of the shield body 1, and a partition wall portion 1A of the body 1 is provided.
The cutter head 3 is rotatably supported by the cutter head 3, the cutter bit is provided on the side of the cutter head 2, and the roller bit 4 is rotatably installed in the installation space 2A formed in the cutter head 2. As described above, the cutter bit 3 has a function of revolving with the cutter head 2 to cut the ground, and the roller bit 4 revolves with the cutter head and rotates with the application of thrust to generate large gravel. It has the function of crushing hard ground such as rocks and bedrock. 5
Is a slewing bearing that receives thrust that connects the shield body 1 and the cutter head 2, 6 is a cutter drive device such as a hydraulic motor attached to the shield body 1 that rotationally drives the cutter head 2 via a gear mechanism, 7 is a center shaft, Reference numeral 8 denotes a rotary joint for connecting a pipeline such as greasing of a roller bit, which is provided inside the machine, to a pipeline in the center shaft 7. The rotary joint 8 is a component that is usually provided in a muddy water shield machine, although it is related to a roller bit rotation detection device of the present embodiment described later. The shield body 1 is provided with a water supply pipe 1B for supplying muddy water such as bentonite to the face and a muddy pipe 1C for discharging excavated earth and sand together with the muddy water, and imparts thrust to the cutter head 2 during excavation. A propulsion jack 1D is installed.

The outline of the construction of the muddy water shield machine has been described above. Next, the construction of the roller bit 4 used in this muddy water shield machine and the present invention is embodied in the roller bit 4. The configuration in this case will be described in detail.

The structure of the roller bit 4 will be described below.
In FIG. 3 and FIG. 4, 9 is a cutter part as a rotating part of the roller bit 4 having several bits, 10 is a through hole 9A in the center of the cutter part 9, and through a roller bearing 14 and a ball bearing 15. A fixed shaft portion called an inner race that rotatably supports the cutter portion 9, and the cutter portion 9 and the fixed shaft portion 10 constitute the roller bit 4. At both ends of the gap between the cutter portion 9 and the fixed shaft portion 10, a seal 12 as a conventional means is provided in order to prevent intrusion of earth and sand or water into the bearing portion. 1
Reference numeral 1 denotes a bracket that is installed and fixed at both ends in the longitudinal direction of the installation space 2A formed in the cutter head 2 and that mounts the fixed shaft portion 10.
A is formed, and attachment pieces 11B for attaching to the cutter head 3 are welded to both sides of the lower end portion. Bracket 4
Has such a structure, the fixed shaft portion 1 of the roller bit 4 is fitted into each mounting hole 11A of the two brackets 11.
After both ends of 0 are fitted and fixed, both brackets 11
Are located at both ends in the longitudinal direction of the installation space 2A, and the respective mounting pieces 11B are screwed onto the lower surface of the cutter head 2, so that as shown in FIG. 2 and FIG.
Can be installed in the installation space 2A formed in the cutter head 2.

The structure when the present invention is embodied in the roller bit 4 will be described.
An oil supply passage 21 for supplying pressure oil, 21 an oil discharge passage for discharging the pressure oil provided on the fixed shaft portion 10, and 22 an oil supply passage 20 and an oil discharge passage 21 provided for the cutter unit 9. Is a communication passage for communicating with each other. The three seals 13 provided at the center of the gap between the cutter portion 9 and the fixed shaft portion 10 are seals for partitioning the oil passage. The oil supply passage 20 and the oil discharge passage 21 are connected to the axial hole that opens at one end of the fixed shaft portion 10, the axial hole and the fixed shaft portion 10, and open to the outer peripheral portion of the fixed shaft portion 10. It is composed of a hole in the radial direction, and one pair is provided on one fixed shaft portion 10. Communication passage 22
One is provided for each cutter unit 9, and a supply port 22a and a discharge port 22b are provided at the inlet side and the outlet side thereof, respectively.
Having. The supply port 22a is formed on the insertion hole 9A side of the cutter portion 9, that is, on the inner peripheral surface so as to form an annular shape by a groove portion continuously engraved along the peripheral surface.
I try to keep in touch with 0. The discharge port 22b is formed on the inner peripheral surface of the cutter unit 9 as an opening having substantially the same cross section as the communication passage 22, so that the discharge port 22b communicates with the oil discharge passage 21 only once during one rotation of the cutter unit 9. It has become.
In this embodiment, only one communication passage 22 is provided in each cutter unit 9, but a plurality of communication passages 22 may be provided at equal intervals, and the plurality of communication passages 22 form one annular supply port 22.
You may make it share a.

Reference numeral 20a denotes a supply pipe line for supplying pressure oil of a hydraulic pump 23 described later, 20b denotes a connection supply pipe line for connecting the supply pipe line 20a to the oil supply line 20, and 21a denotes a drainage oil through a communication path 22. A discharge pipe line for discharging the pressure oil of the oil supply line 20 guided to the line 21 to the oil tank 24 described below, 21b is a connection discharge pipe line for connecting the oil discharge line 21 to the discharge pipe line 21a, and 23 is Hydraulic pump as means for generating pressure oil, 2
Reference numeral 4 is an oil tank for storing oil that generates pressure oil and returning used pressure oil. As shown in FIGS. 1 and 2, the connection supply pipe line 20b and the connection discharge pipe line 21b are directly guided to the inside of the cutter head 2 adjacent to the fixed shaft portion 10 and then separated through the cutter shaft 7. It is guided to the inside of 1A, that is, the inside of the machine, and is connected to the supply pipeline 20a and the discharge pipeline 21a by the rotary joint 8, respectively. Reference numeral 25 is a relief valve provided upstream of the pressure sensor 26 to release the pressure oil to the secondary side when the pressure of the pressure oil on the primary side reaches the set pressure P _B1 , and 25a is a supply valve provided with the relief valve 25. Bypass from the line 20a and discharge line 21
a relief circuit connected to a, 26 is a supply line 20
A pressure sensor that detects a pressure drop of the pressure oil of a and emits an electric signal, 27 is an indicator light as a display means which blinks by an electric signal emitted by the pressure sensor 26, and 28 is a work chamber in which the indicator light 27 is attached. Display board installed,
Reference numeral 29 is a cable for sending an electric signal generated by the pressure sensor 26 to the indicator light 27. As shown in FIG.
When the oil supply passage 20 and the oil discharge passage 21 are not communicated with each other through the communication passage 22, the hydraulic pressure of the supply pipe passage 20a rises and reaches the set pressure P _B1 of the relief valve 25.
Releases the pressure oil in the supply pipeline 20a to the oil tank 24 through the relief circuit 25a. At this time, the detected pressure P _A1 detected by the pressure sensor 26 becomes equal to the set pressure P _B1 of the relief valve 25, and the pressure sensor 26 does not emit the electric signal for lighting the indicator lamp 27 in such a case.
Further, as shown in FIG. 5A, the oil supply passage 20 and the oil discharge passage 2
When 1 is communicated with the communication passage 22, the connection supply pipeline 20b, the oil supply passage 20, and the annular supply port 22a of the communication passage 22.
Since the hydraulic pressure of the supply pipeline 20a guided to the discharge port 22b of the communication passage 22 is discharged to the oil tank 24 through the oil discharge passage 21, the hydraulic pressure of the supply pipeline 20a drops sharply and the relief valve 25 It becomes lower than the set pressure P _B1 . At this time, the detected pressure P _A1 of the pressure sensor 26 also becomes lower than the set pressure P _B1 of the relief valve 25, and the pressure sensor 26 emits an electric signal for lighting the indicator lamp 27 in such a case. In this way, the pressure sensor 26 issues an electric signal when the oil supply passage 20 and the oil discharge passage 21 are communicated with each other by the communication passage 22 and a flow of pressure oil occurs in the supply pipe passage 20a.
It functions as a detection means for detecting the flow of pressure oil inside. Note that the pressure sensor 26 may not emit the electric signal for turning on the indicator light 27 in the case of FIG. 5A, and may emit the electric signal in the case of FIG. 5B. The point is that an electric signal for blinking the indicator light 27 may be emitted.

The embodiment in which the roller bit rotation detecting device of the present embodiment is applied to one of the four roller bits 4 shown in FIG. 2 has been described above. It is carried out in the same manner as this. In that case, the connecting discharge pipe 21b guided to the inside of the machine and connected to the discharge pipe 21a by the rotary joint 8 is merged in the cutter head 2 or the cutter shaft 7 in order not to make the rotary joint 8 large. Although it is possible to make one, in the present embodiment, they are merged into one in the cutter shaft 7, and accordingly, the number of the discharge pipes 21a is also made one. In addition, the relief valve 25 and the pressure sensor 2
Even if 6 and related pipelines such as the supply pipeline 20a are individually provided according to the number of roller bits 4, the hydraulic pump 23 uses a flow divider or other flow divider having a pressure compensation function. It can be unified by branching the supply pipeline 20a. In this embodiment, since four roller bits 4 are provided on the cutter head 2 as shown in FIG. 2, four indicator lights 17 of the same number as the roller bits 4 are attached to the display plate 16. Therefore, each of these indicator lights 17 is arranged on a figure similar to the cutter head 2 drawn on the display plate 16 so that it can be discriminated which roller bit 4 installed on the cutter head 2 corresponds to. ing.

Since the roller bit rotation detecting device of the embodiment of the present invention has the above-described structure, it is rotated by the cutter driving device 6 while applying thrust to the cutter head 2 by the propulsion jack 1D. When driven, each roller bit 4 revolves while revolving to crush hard ground. The cutter portion 9 provided with the communication passage 22 rotates around the fixed shaft portion 10 as the roller bit 4 rotates, and the discharge port 22b of the communication passage 22 rotates once during one rotation. Call 21. That is, the oil supply passage 20 and the oil discharge passage 21 are intermittently communicated with each other through the communication passage 22 as the cutter unit 9 rotates, and the pressure oil in the oil supply passage 20 is guided to the oil discharge passage 21 and escaped to the oil tank 24. . Then, the hydraulic pressure in the supply pipe 20a drops sharply every time the pressure oil is released to the oil tank 24, and becomes lower than the set pressure P _B1 of the relief valve 25. Detection pressure P _A1
Since it also becomes lower than the set pressure P _B1 of the relief valve 25, the pressure sensor 26 gives an electric signal for lighting the indicator lamp 27. As a result, all the indicator lights 27 on the display plate 28 corresponding to each roller bit 4 blink regularly at equal intervals as long as the rotation of each roller bit 4 is smoothly performed. When the rotation of the roller bit 4 is not smoothly performed, the indicator light 27 corresponding to the roller bit 4 blinks irregularly. Further, when the roller bit 4 becomes non-rotatable, the indicator light 27 corresponding to the roller bit 4 either remains lit or remains unlit. Thus, the operator of the muddy water shield machine can monitor the respective indicator lights 27 on the indicator plate 28 provided in the work room so as to smoothly rotate the roller bits 4 during the excavation of the natural ground. Whether or not you can always know exactly whether or not there is an abnormality,
The necessary measures can be taken in a planned and timely manner.

In the roller bit rotation detecting device according to the embodiment of the present invention, the oil supply passage 20, the oil discharge passage 21 and the communication passage 22 which constitute the rotation detecting means of the roller bit 4 have the cutter portion 9 and the fixed shaft portion 10 in particular. Since it is installed inside, and it is installed collectively in places where there is no danger of ingress of dirt, water, etc., unlike the conventional technology that provided a proximity switch etc. as the rotation detection means of the roller bit, The rotation detecting means of the bit is not damaged or worn by debris or earth and sand water that has been cut or crushed. Further, the roller bit 4 is only provided with an oil passage and is not provided with a pressure sensor 26 as a detecting means. This pressure sensor 26 is an appropriate one of the supply pipe passage 20a piped inside the partition wall 1A. Since it is provided in a place, unlike the detection means in the prior art, there is no impact due to scattering of debris, etc.
There is no risk of failure due to such impact. Further, both the connection supply pipeline 20b for connecting the supply pipeline 20a to the oil supply passage 20 and the connection discharge pipeline 21b for connecting the drain oil passage 21 to the discharge pipeline 21a are both fixed shaft portions. After being directly guided to the inside of the cutter head 2 adjacent to 10, it is guided to the inside of the partition wall 1A through the inside of the cutter shaft 7, so that it is not exposed to the outside and there is no fear of damage, and its piping is simple. You can do it. In manufacturing the roller bit rotation detecting device of this specific example, it is sufficient to provide only the oil passages such as the oil supply passage 20, the oil discharge passage 21 and the communication passage 22 in the roller bit 4, and therefore the roller bit 4 It can be easily attached at the time of manufacturing and is easy to manufacture. Further, as described above, since the oil passages such as the oil supply passage 20, the oil discharge passage 21 and the communication passage 22 are integrated with the roller bit 4, when the roller bit 4 is replaced, parts relating to the roller bit rotation detection device. It is sufficient to replace only the roller bit 4 without the need for replacement work, and the replacement can be performed easily.

In this embodiment, the roller bit rotation detecting device of the present invention is a roller bit 14 of a muddy water shield machine.
However, the pressure sensor 26 can also be applied to roller bits of other drilling rigs.
Will be installed in a place different from the roller bit so that maintenance can be done, as in the case of applying to a muddy water shield machine. In this specific example, when the cutter portion 9 is provided with only one communication passage 22 for communicating the oil supply passage 20 with the oil discharge passage 21, only one such communication passage 22 is provided as described above. Plural can be provided. In this specific example, the communication passage 22 has a supply port 22a formed in an annular shape so as to be constantly in communication with the oil supply passage 20, and the discharge port 22b has an opening having substantially the same cross section as the communication passage 22. However, this may be reversed, and the point is that the oil supply passage 20 and the oil discharge passage 21 may be intermittently connected to each other as the cutter unit rotates. The same applies to the oil supply passage 20 and the oil discharge passage 21. In this specific example, the pressure sensor 26 is used as a means for emitting an electric signal for blinking the indicator light 27 to detect the pressure drop of the pressure oil in the supply pipeline 20a. After returning, since it is a means for detecting the flow of pressure oil in the supply pipeline 20a, for example, a throttle is provided in the supply pipeline 20a so that the differential pressure before and after it can be detected, or a flow meter is provided. Other means may be used as long as it can detect the flow of pressure oil, such as detecting the fact that the pressure oil of the oil supply passage 20 is guided to the oil discharge passage 21 and blinking the indicator light 27. Any kind of means can be used as long as it is a means capable of issuing a signal for causing the operation. In this embodiment, the indicator lamp 27 is used as the display means, but the display means may be any device using light, an image, a sound or the like. In this embodiment, pressure oil is supplied to the fixed shaft portion 10 in order to detect the rotation of the roller bit 14, but instead of this pressure oil, water,
Other pressure fluids such as air can be used.

[0023]

As is apparent from the above description, in the roller bit rotation detecting device of the present invention, the oil supply passage, the oil discharge passage and the communication passage constituting the rotation detecting means of the roller bit are particularly the cutter portion and the fixed shaft portion. Since it is provided inside, and it is provided together in a place where dirt, water, etc. are not inherently intruded, unlike the conventional technology in which a proximity switch or the like is provided as the rotation detecting means of the roller bit, The rotation detecting means of the roller bit is not damaged or worn by debris or earth and sand water that has been cut or crushed. Further, the roller bit is only provided with an oil passage, and is not provided with a detection means for issuing a signal for operating the display means. This detection means is provided at an appropriate position different from the roller bit. Since it is designed to be installed in the
There is no impact due to scattering of debris, and there is no risk of failure due to such impact. Further, when manufacturing the roller bit, it is sufficient to provide only oil passages such as an oil supply passage, an oil discharge passage, and a communication passage, and therefore, the roller bit can be easily attached to the roller bit and the production is easy. Also,
In this way, since the oil passages such as the oil supply passage, the oil discharge passage, and the communication passage are integrated with the roller bit, when the roller bit is replaced, it is not necessary to replace the parts related to the roller bit rotation detection device. Only the roller bit needs to be replaced, which can be done easily. As described above, according to the present invention, it is possible to solve all the problems of the prior art and obtain a practical roller bit rotation detecting device that can withstand long-term use.

[Brief description of drawings]

FIG. 1 is a side view showing a specific example when the roller bit rotation detection device of the present invention is applied to a muddy water shield type excavator.

FIG. 2 is a view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a cross section taken along the line CC of FIG.

5A and 5B are hydraulic circuit diagrams for explaining the operation of the roller bit rotation detection device according to the embodiment of the present invention, in which FIG. 5A is a diagram showing a state when the oil supply passage and the oil discharge passage are in communication, and FIG. FIG. 4 is a diagram showing a state where these oil passages are not in communication.

[Explanation of symbols]

 2 cutter head 4 roller bit 8 rotary joint 9 cutter portion 9A insertion hole 10 fixed shaft portion 20 oil supply passage 20a supply pipe passage 20b connection supply pipe passage 21 oil discharge passage 21a discharge pipe passage 21b connection discharge pipe passage 22 communication passage 22a Supply port 22b Discharge port 25 Relief valve 25a Relief line 26 Pressure sensor 27 Indicator light 28 Indicator plate 29 Cable

Claims (2)

[Claims] 1. A roller bit having a cutter portion and a fixed shaft portion which is inserted into the cutter portion and rotatably supports the cutter portion. In the roller bit, a fluid supply path for supplying a fluid to the fixed shaft portion and a fluid are discharged. A fluid discharge passage for connecting the fluid supply passage and the fluid discharge passage to the cutter, and the fluid supply passage and the fluid discharge passage are connected to each other as the cutter rotates. A signal for intermittently communicating with the passage so as to guide the fluid in the fluid supply passage to the fluid discharge passage, and to detect that the fluid in the fluid supply passage is led to the fluid discharge passage to operate the display means. A roller bit rotation detecting device, characterized in that the detecting means for emitting the signal is provided at a location different from the roller bit. 2. The pressure drop of the fluid on the fluid supply path side is detected as a detection means for detecting that the fluid in the fluid supply path is guided to the fluid discharge path and issuing a signal for operating the display means. 2. The roller bit rotation detecting device according to claim 1, wherein the fluid bit pressure detecting means is provided, and a relief valve capable of releasing the fluid on the fluid supply path side is provided upstream of the fluid pressure detecting means.