Hob with pressure equalization

Abstract

The utility model relates to the technical field of hob, disclose a hob with pressure balance function, including the cutter shaft, the first step hole is opened to the one end of cutter shaft along the axial, the circumferential side of cutter shaft is opened to have the vice hole along the radial, the small diameter end of vice hole is linked together with the first step hole, the big diameter end of first step hole is installed with screw, screw is opened to have the second step hole along the axial, the first step hole is slidably installed with the cylinder seat, the circumferential side of cylinder seat is opened to have the first ring groove, the first ring groove is equipped with the first rubber ring, and the first rubber ring is in the first step hole;The inside of cylinder seat is provided with hole shoulder, and hole shoulder separates the inside of cylinder seat to form utility cavity and movable cavity, installs one-way air valve in utility cavity, and installs balance assembly in movable cavity. The utility model discloses a first order balance effect of sliding formation through cylinder seat, and the second order balance effect of sliding formation through piston post, realize the dynamic balance of the air pressure in and out of sealed cavity, guarantee the service life of hob.

Description

Technical Field

[0001] This utility model relates to the field of hobbing technology, specifically to a hobbing cutter with pressure balancing function. Background Technology

[0002] The main structure of the tunnel boring machine cutterhead includes the cutter ring (for rock breaking), the cutter body (for fixing the cutter ring, supporting the bearing, and protecting the seal), the cutter shaft (for transmitting power), the floating seal assembly (with two pairs of sealing rings to prevent mud and water from entering the sealing cavity inside the cutterhead and to protect the bearing), the end caps (for sealing both ends of the cutterhead), and the retaining rings (for fixing the cutter ring).

[0003] The cutter head is replaced only after the excavation work has reached the set service life. During operation, the cutter head rotates and feeds along with the cutterhead of the tunnel boring machine, achieving efficient crushing through the mechanism of rock crushing by compression. Due to different working environments of the cutter head, a pressure difference will form inside and outside the sealing cavity. For example, in earth pressure balance tunnel boring machines, the cutter head is in a working environment of long-term soil chamber pressure coupling, which will cause the pressure inside the sealing cavity to be lower than the external pressure. This will cause the rubber O-ring of the sealing ring to shift, resulting in the failure of the sealing function. External impurities such as mud, sand and water will enter the sealing cavity, causing bearing damage and shortening the service life of the cutter head.

[0004] Under normal operating conditions, the increased temperature from the hobbing operation and the increased mechanical friction due to the bearing stress will cause the temperature inside the sealing cavity to rise continuously, resulting in the internal pressure of the sealing cavity being greater than the external pressure. This will also cause the rubber O-ring of the sealing ring to shift, leading to the failure of the sealing function. Therefore, in order to solve the above problems, a hobbing cutter with pressure balancing function is proposed. Utility Model Content

[0005] The purpose of this invention is to provide a roller cutter with pressure balancing function, which can balance the air pressure in the sealing cavity and prevent the sealing ring from shifting, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a hobbing cutter with pressure balancing function, comprising a cutter shaft, one end of which has a first stepped hole along the axial direction, and a secondary hole along the radial direction on the circumferential side of the cutter shaft, the secondary hole communicating with the small-diameter end of the first stepped hole, a screw installed at the large-diameter end of the first stepped hole, the screw having a second stepped hole along the axial direction, a cylinder seat slidably installed in the first stepped hole, a first annular groove being formed on the circumferential side of the cylinder seat, a first rubber ring being fitted inside the first annular groove, the first rubber ring abutting against the first stepped hole; the cylinder seat has a shoulder inside, the shoulder separating the interior of the cylinder seat into a facility cavity and a movable cavity, a one-way air valve being installed in the facility cavity, and a balancing component being installed in the movable cavity.

[0007] Specifically, the balancing assembly includes a spring, a piston rod, and a retaining ring. The piston rod is slidably installed in the movable cavity. The spring is located in the movable cavity and abuts against the shoulder of the bore and the piston rod. A retaining groove is provided at the end of the movable cavity away from the shoulder of the bore, and a retaining ring is installed in the retaining groove.

[0008] Furthermore, the balancing assembly also includes a second rubber ring, and a second annular groove is provided on the circumferential side of the piston rod. The second rubber ring is fitted inside the second annular groove and abuts against the movable cavity.

[0009] Specifically, the first rubber ring consists of 2 to 4 rings evenly distributed along the axial direction of the cylinder seat, and the second rubber ring consists of 2 to 3 rings evenly distributed along the axial direction of the piston rod.

[0010] Specifically, the one-way valve has a venting groove on the side away from the shoulder of the orifice.

[0011] Specifically, the large-diameter end of the second stepped hole is located near the shoulder side of the hole, and a filter block is installed inside the large-diameter end of the second stepped hole.

[0012] Compared with the prior art, the beneficial effects of this utility model are: The first-order balancing effect formed by the sliding of the cylinder seat and the second-order balancing effect formed by the sliding of the piston rod achieve dynamic balance of air pressure inside and outside the sealing cavity. Under extreme working conditions where the pressure inside the sealing cavity is much greater than the external pressure, the second-order balancing can further discharge excess gas. This dual air pressure balancing mechanism avoids the displacement of the sealing ring caused by air pressure difference, effectively prevents external impurities such as mud and water from entering the sealing cavity, and ensures the service life of the cutter.

[0013] In addition, even if the filter block is damaged and loses its filtering function due to harsh environment, the combined action of the first-order balancing action and the second-order balancing action can still balance the internal and external air pressure, making the structure stable and durable. Attached Figure Description

[0014] Figure 1 This is a partial sectional view illustrating the structure of this utility model; Figure 2 This is a partial sectional view of the structure of the cutter shaft of this utility model; Figure 3 This is a schematic cross-sectional view of the structure at the cylinder seat of this utility model; Figure 4 This is a schematic cross-sectional view of the screw part of this utility model.

[0015] In the diagram: 1. Cutter shaft, 2. First step hole, 3. Cylinder seat, 4. First rubber ring, 5. One-way air valve, 6. Balance assembly, 61. Spring, 62. Second rubber ring, 63. Piston post, 64. Snap ring, 7. Shoulder, 8. Filter block, 9. Second step hole, 10. Screw, 11. Secondary hole, 12. Vent groove. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1 and Figure 2 This utility model provides a hob with pressure balancing function, including a cutter shaft 1. One end of the cutter shaft 1 has a first stepped hole 2 opened along the axial direction. The circumferential side of the cutter shaft 1 has a secondary hole 11 opened along the radial direction. The secondary hole 11 is connected to the small diameter end of the first stepped hole 2. The secondary hole 11 is aligned with the sealing cavity of the hob, thereby realizing the communication between the sealing cavity and the first stepped hole 2. A screw 10 is installed at the large diameter end of the first stepped hole 2. The screw 10 has a second stepped hole 9 opened along the axial direction. The second stepped hole 9 can realize the communication between the first stepped hole 2 and the outside, for the circulation of internal and external gases.

[0018] A cylindrical seat 3 is slidably installed inside the first stepped hole 2. A first annular groove is provided on the circumferential side of the cylindrical seat 3. A first rubber ring 4 is fitted inside the first annular groove. The first rubber ring 4 abuts against the first stepped hole 2. The first rubber ring 4 is used to further seal the gap between the cylindrical seat 3 and the first stepped hole 2, playing a sealing role, preventing gas leakage at the small diameter end of the first stepped hole 2, and ensuring that the cylindrical seat 3 can be effectively pushed.

[0019] When the pressure inside the sealing cavity is greater than that outside, the cylinder seat 3 will slide towards the side closer to the screw 10, and at the same time, the excess gas in the first step hole 2 will be discharged through the second step hole 9. When the pressure inside the sealing cavity is less than that outside, the cylinder seat 3 will slide away from the screw 10. At this time, the external gas will enter the first step hole 2 through the second step hole 9 to replenish it, thereby achieving the purpose of balancing the gas pressure inside and outside the sealing cavity.

[0020] The sliding of the cylinder seat 3 within the first stepped hole 2 creates a first-order balancing effect.

[0021] The first stepped hole 2 and the second stepped hole 9 are both stepped holes formed by a large-diameter hole and a small-diameter hole coaxially connected. The large-diameter end refers to the end away from the small-diameter hole, and the small-diameter end refers to the end away from the large-diameter hole.

[0022] The interior of the cylinder base 3 is provided with a shoulder 7, which separates the interior of the cylinder base 3 to form a facility cavity and a movable cavity. Since there is a through hole at the center of the shoulder 7, the facility cavity and the movable cavity are also connected. A one-way air valve 5 is installed in the facility cavity, and a balancing component 6 is installed in the movable cavity. The balancing component 6 can further balance the high pressure at the right end of the first step hole 2 and discharge the air in the movable cavity through the one-way air valve 5.

[0023] The one-way air valve 5 is used to discharge the gas in the active chamber into the first step hole 2 in one direction, while the air in the first step hole 2 cannot enter the active chamber. It plays a role in dust prevention and waterproofing, preventing foreign objects such as dust and water from entering the active chamber and thus affecting the normal operation of the balance component 6.

[0024] The one-way air valve 5 is an existing component mainly composed of a valve body, a ball core, and a spring. The valve body has an exhaust end on the upper side and an air inlet end on the right side. The ball core is pressed against the air inlet end under the action of the spring, realizing the one-way exhaust function from the air inlet end to the exhaust end and the blocking function from the exhaust end to the air inlet end.

[0025] The one-way valve 5 can be installed by a threaded connection. That is, the valve body of the one-way valve 5 has an external thread section on the outer circumference and the device cavity has an internal thread section on the inner circumference. The installation of the one-way valve 5 is completed by screwing the external thread section and the internal thread section, and disassembly is convenient.

[0026] Please see Figure 3 The specific structure of the balancing component 6 is as follows: The balancing assembly 6 includes a spring 61, a piston rod 63, and a retaining ring 64. The piston rod 63 is slidably installed in the movable cavity. The spring 61 is located in the movable cavity and abuts against the shoulder 7 and the piston rod 63. The spring 61 causes the piston rod 63 to have a resetting force to the side away from the shoulder 7. A retaining groove is opened at the end of the movable cavity away from the shoulder 7. The retaining ring 64 is installed in the retaining groove. The retaining ring 64 plays a limiting role to prevent the piston rod 63 from coming out of the movable cavity.

[0027] When the pressure inside the sealed cavity is much greater than the external pressure, the first-order balancing action is used up first. That is, when the cylinder seat 3 moves to the left to the limit position, and the one-way valve 5 abuts against the screw 10, but the internal and external air pressures are still not balanced, the piston column 63 will slide to the left along the movable cavity, while compressing the spring 61 and discharging the excess gas in the movable cavity through the one-way valve 5, thus achieving the purpose of balancing the internal and external air pressures.

[0028] The balancing assembly 6 also includes a second rubber ring 62. A second annular groove is provided on the circumferential side of the piston column 63, and the second rubber ring 62 is fitted inside the second annular groove. The second rubber ring 62 abuts against the movable cavity. The second rubber ring 62 is used to seal the gap between the piston column 63 and the movable cavity, and plays a sealing role to prevent gas leakage in the movable cavity and ensure that the piston column 63 can be effectively pushed.

[0029] The sliding of piston rod 63 within the movable cavity creates a second-order equilibrium effect.

[0030] When the pressure inside the sealed cavity suddenly increases, the first-order balance and the second-order balance can also work simultaneously, that is, both the cylinder seat 3 and the piston column 63 move to the left, and the balancing effect is significant.

[0031] In addition, there are 2 to 4 first rubber rings 4 evenly distributed along the axial direction of the cylinder seat 3, and 2 to 3 second rubber rings 62 evenly distributed along the axial direction of the piston column 63. The arrangement of multiple first rubber rings 4 can further improve the sealing performance between the cylinder seat 3 and the first stepped hole 2, and the arrangement of multiple second rubber rings 62 can further improve the sealing performance between the piston column 63 and the moving cavity, avoiding sealing failure caused by the aging or damage of a single rubber ring.

[0032] A ventilation groove 12 is provided on the side of the one-way air valve 5 away from the shoulder 7. When the one-way air valve 5 abuts against the screw 10, the ventilation groove 12 can ensure that the exhaust end of the one-way air valve 5 is connected to the second step hole 9, thereby allowing the internal gas to be discharged to the outside of the cutter shaft 1.

[0033] Please see Figure 4 The large-diameter end of the second step hole 9 is located near the shoulder 7, and a filter block 8 is installed inside the large-diameter end of the second step hole 9. The filter block 8 is made of polyester fiber to prevent dust from the external environment from entering the first step hole 2. The filter block 8 is fixedly installed inside the large-diameter end of the second step hole 9 by adhesive bonding to ensure its strength.

[0034] Working principle: During a single excavation operation, the cutter head moves along with the tunnel boring machine: In scenario one, the air pressure inside the cutter sealing cavity is lower than the external air pressure. In this case, the pressure difference between the inside and outside of the sealing cavity will not be large, and the internal and external air pressure can be balanced by sliding the cylinder seat 3 to the right slightly.

[0035] In the second scenario, the hob is in a high-load operating state for a long time. Factors such as the overall temperature of the hob rising and the mechanical friction caused by the bearing being stressed will result in the air pressure inside the sealing cavity being higher than the external air pressure. At this time, the air pressure difference between the inside and outside of the sealing cavity will be large. The first-order balancing effect will take effect first, that is, the cylinder seat 3 will slide to the left along the first step hole 2 until the one-way air valve 5 abuts against the screw 10.

[0036] In extreme operating environments, the air pressure balance may not be complete, and the internal air pressure may be greater than the external air pressure. At this time, the second-order balancing action will take effect again, that is, the piston column 63 will slide to the left along the movable chamber, while compressing the spring 61, and discharging the excess gas in the movable chamber through the one-way air valve 5, and finally discharging it from the second step hole 9, which plays the role of limit protection.

[0037] Under the relatively reduced air pressure fluctuation in the sealed cavity, due to the setting of the one-way air valve 5, the piston column 63 will not reset, preventing impurities from entering the moving cavity through the one-way air valve 5. Instead, it will slide slightly to the right through the cylinder seat 3 in the first step hole 2 to balance this small air pressure fluctuation. In one working cycle of the hob, the air pressure inside and outside the sealed cavity can be balanced.

[0038] In addition, if the filter block 8 is damaged due to an accident and loses its filtering function, water, soil and other foreign objects may enter the first step hole 2 on the left side of the cylinder seat 3, jamming the cylinder seat 3 and preventing it from moving to the left to balance the air pressure. In this case, the second-stage air pressure will directly act, that is, the piston column 63 will slide to the left along the movable cavity to balance the excessively high internal air pressure. If the air pressure inside the sealed cavity is slightly lower than the external air pressure, the cylinder seat 3 can still slide to the right to balance the external high pressure because the first step hole 2 on the right side of the cylinder seat 3 is clean, and it will not lose its air pressure regulation function.

[0039] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0040] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A hob with pressure balancing function, comprising a cutter shaft (1), characterized in that: One end of the cutter shaft (1) is provided with a first stepped hole (2) along the axial direction. The circumferential side of the cutter shaft (1) is provided with a secondary hole (11) along the radial direction. The secondary hole (11) is connected to the small diameter end of the first stepped hole (2). A screw (10) is installed at the large diameter end of the first stepped hole (2). The screw (10) is provided with a second stepped hole (9) along the axial direction. A cylinder seat (3) is slidably installed in the first stepped hole (2). A first annular groove is provided on the circumferential side of the cylinder seat (3). A first rubber ring (4) is sleeved in the first annular groove. The first rubber ring (4) abuts against the first stepped hole (2). The cylinder seat (3) has a shoulder (7) inside, which separates the interior of the cylinder seat (3) into a facility cavity and a movable cavity. A one-way air valve (5) is installed in the facility cavity, and a balancing component (6) is installed in the movable cavity.

2. The hob with pressure balancing function according to claim 1, characterized in that: The balancing assembly (6) includes a spring (61), a piston rod (63), and a retaining ring (64). The piston rod (63) is slidably installed in the movable cavity. The spring (61) is located in the movable cavity and abuts against the shoulder (7) and the piston rod (63). A retaining groove is provided at the end of the movable cavity away from the shoulder (7), and a retaining ring (64) is installed in the retaining groove.

3. The hob with pressure balancing function according to claim 2, characterized in that: The balancing assembly (6) also includes a second rubber ring (62). A second annular groove is provided on the circumferential side of the piston column (63). The second rubber ring (62) is sleeved in the second annular groove and abuts against the movable cavity.

4. The hob with pressure balancing function according to claim 3, characterized in that: The first rubber ring (4) consists of 2 to 4 rings evenly distributed along the axial direction of the cylinder seat (3), and the second rubber ring (62) consists of 2 to 3 rings evenly distributed along the axial direction of the piston rod (63).

5. The hob with pressure balancing function according to claim 1, characterized in that: The one-way air valve (5) has an air vent (12) on the side away from the shoulder (7).

6. The hob with pressure balancing function according to claim 1, characterized in that: The large-diameter end of the second stepped hole (9) is located near the shoulder (7), and a filter block (8) is installed inside the large-diameter end of the second stepped hole (9).

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