Electric revolving door for cold and hot aisles of a machine room
By using a dust collection and cleaning device and a shaft lubrication device, the problems of dust accumulation and insufficient lubrication in the electric revolving door of the computer room were solved, achieving efficient cleaning and stable operation and extending the service life of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEBEI WONDER CABINETS MFG CO LTD
- Filing Date
- 2025-07-30
- Publication Date
- 2026-07-21
AI Technical Summary
Existing electric revolving doors suffer from dust accumulation and inefficient cleaning in computer room environments, as well as insufficient lubrication of the rotating shaft, which affects the cleanliness and service life of the equipment.
The design includes a dust collection and cleaning device and a shaft lubrication device. The dust collection and cleaning device includes components such as a collection box, a dual-output shaft motor, a threaded rod, and a cleaning brush. The threaded rod drives the moving plate and the cleaning brush to remove dust. The shaft lubrication device includes components such as an oil tank, an oil supply pipe, and a micro motor to achieve timed lubrication of the shaft.
It effectively removes dust, extends the service life of the rotating shaft, improves cleaning efficiency and the reliability of the lubrication system, and ensures the stable operation of the revolving door.
Smart Images
Figure CN224532595U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of intelligent door technology, specifically to an electric revolving door for hot and cold passages in a computer room. Background Technology
[0002] In a data center environment, hot and cold aisle isolation is crucial for maintaining stable equipment operation. Traditional data center door designs often neglect door hinge lubrication and dust accumulation at the bottom of the door, which not only affects the lifespan of the door but may also adversely impact the cleanliness and temperature control of the data center.
[0003] According to a public disclosure (CN104563795A), an electric revolving door includes a glass door, a door frame, and pillars. An infrared detector is installed at one end of the glass door, springs are installed at both ends of the door frame, and a protective device is installed on the pillars. An alarm light is installed on the outer surface of the protective device. When the glass door encounters an obstruction, the infrared detector sends a signal to the protective device, the alarm light flashes, and the protective device gradually slows the rotation speed of the glass door until it stops. The springs act as buffers, cushioning the impact between the glass door and the door frame. This invention provides an electric revolving door with a reasonable structural design. Due to the inclusion of the protective device, infrared detector, and springs, the speed of the electric revolving door is effectively controlled, allowing for a faster and more uniform slowdown and stop, preventing pedestrian injuries and improving safety, making it more user-friendly.
[0004] The aforementioned applications control the speed of the electric revolving door through infrared detectors and springs, which improves safety. However, they do not effectively address the lubrication of the door hinges and the accumulation of dust at the bottom of the door, which are specific to the characteristics of the computer room environment. This results in dust accumulation inside the door, making it difficult to clean. Therefore, we propose an electric revolving door for hot and cold aisles in computer rooms. Utility Model Content
[0005] To overcome the above-mentioned defects, this utility model provides an electric revolving door for hot and cold aisles in computer rooms, which solves the technical problem that dust accumulation in existing electric revolving doors cannot be cleaned efficiently.
[0006] According to one aspect, at least one embodiment of the present invention provides an electric revolving door for hot and cold aisles in a computer room, comprising: a hot aisle, a front aisle door at the bottom of the hot aisle, a rear aisle door at the bottom of the hot aisle, and a dust collection and cleaning device at the bottom of the front aisle door.
[0007] The dust collection and cleaning device includes a collection box, the bottom of which is fixedly connected to the bottom of the front passage door. A dual-output shaft motor is fixedly connected to the side of the collection box, and a threaded rod is fixedly connected to the output shaft of the dual-output shaft motor. A threaded sleeve is threadedly connected to the circumferential surface of the threaded rod, and a movable plate is fixedly connected to the circumferential surface of the threaded sleeve. A cleaning brush is fixedly connected to the bottom of the movable plate. A limit post is fixedly connected to the inner wall of the collection box. A dust collection trough is opened on the top of the collection box, and a dust collection plate is fixedly connected to the inner wall of the dust collection trough. A fan is fixedly connected to the end of the dual-output shaft motor away from the threaded rod. A heat dissipation box is fixedly connected to the side of the collection box, and a dust collection box is fixedly connected through and to the side of the collection box.
[0008] For example, in at least one embodiment of the present invention, an electric revolving door for hot and cold passages in a computer room is provided, which further includes: a buffer spring fixedly connected to the inner wall of the collection box, a buffer pad fixedly connected to the end of the buffer spring away from the collection box, and a dust baffle fixedly connected to the inner wall of the collection box. The function of the buffer pad is to improve the service life of the buffer pad. At the same time, the buffer pad can provide secondary protection against dust, prevent the increase of dust and wear on the threaded rod, and further improve the dust collection effect.
[0009] The side of the buffer pad is located on the displacement trajectory of the side of the moving plate. There are two buffer springs and buffer pads, which are symmetrically distributed along the vertical central axis of the collection box. Their function is to buffer the moving plate, prevent the moving plate from hitting the inner wall of the collection box at too fast a speed, and prevent damage to the moving plate and the collection box, thereby improving the service life of the dust collection and cleaning device.
[0010] The heat sink box has several through holes on one side and an exhaust groove on the other side. The dual-shaft motor is located inside the heat sink box. Its function is to effectively dissipate heat through the through holes and exhaust groove, prevent the motor from overheating, ensure the motor runs stably for a long time, and extend the service life of the equipment.
[0011] The bottom of the cleaning brush is slidably connected to the inner bottom of the collection box, and the side of the moving plate is slidably connected to the side of the dust collection plate. Its function is to ensure that the cleaning brush can effectively scrape off and collect dust during the movement, and the dust collection plate works in sync to improve dust collection efficiency, reduce omissions, and ensure efficient operation of the device.
[0012] The side of the movable plate is slidably connected to the circumferential surface of the limiting post. There are two dust collection plates, which are symmetrically distributed along the vertical central axis of the collection box. Their function is to guide the trajectory of the movable plate during movement, avoid deviation, ensure that the dust collection plates are evenly stressed and work together, and further improve the accuracy of dust collection and the overall stability of the device.
[0013] According to another aspect, at least one embodiment of this utility model also provides an electric revolving door for hot and cold aisles in a computer room, comprising: a shaft lubrication device provided at the top of the front aisle door, the shaft lubrication device including an oil tank, the oil tank being fixedly connected to the top of the front aisle door, an oil supply pipe being passed through and fixedly connected to the side of the oil tank, a support plate being fixedly connected to the top of the front aisle door, a micro motor being fixedly connected to the top of the support plate, an oil pump being fixedly connected to the output shaft of the micro motor, and an oil dripping pipe being passed through and fixedly connected to the circumference of the oil supply pipe. Its function is to drive the oil pump through the micro motor to deliver lubricating oil through the oil supply pipe to the oil dripping pipe, and drip it into the shaft at regular intervals to reduce friction, extend the service life of the shaft, and ensure the smooth operation of the revolving door.
[0014] For example, in at least one embodiment of the present invention, an electric revolving door for hot and cold passages in a computer room is provided, which further includes: a fixing plate fixedly connected to the end of the oil supply pipe away from the oil tank; the interior of the oil pump penetrates and is fixedly connected to the circumferential surface of the oil supply pipe; the function of the fixing plate is to ensure stable oil supply from the oil pump; the fixing plate enhances the stability of the oil supply pipe, avoids oil circuit blockage, improves the reliability of the lubrication system, and further ensures the smooth operation and long-term stability of the revolving door.
[0015] The oil tank has an oil inlet at the top, and the oil drip pipe is located directly above the pivot of the front passage door. Its function is to facilitate the precise dripping of lubricating oil into the pivot, avoid waste, ensure lubrication effect, and improve the smooth operation and service life of the revolving door.
[0016] Two oil drip pipes are provided and symmetrically distributed along the vertical central axis of the front passage door. The side cross-section of the oil supply pipe is set in a U-shape. Its function is to enhance the pressure resistance of the oil supply pipe, optimize the oil circuit circulation, ensure the uniform distribution of lubricating oil, further reduce the wear of the rotating shaft, and improve the overall operating efficiency and durability of the revolving door.
[0017] The beneficial effects of the embodiments of this utility model are as follows: 1. This utility model achieves effective cleaning of dust at the bottom of the electric revolving door in the hot and cold aisles of the computer room through the cooperation of components such as the collection box, dual-shaft motor, and threaded rod. The threaded rod drives the moving plate and cleaning brush to move, and the cleaning brush sweeps the dust into the collection box, further sucking the dust into the collection box, thus improving dust collection efficiency. The use of buffer springs and buffer pads cushions the moving plate, preventing it from impacting the inner wall of the collection box and causing damage, thereby extending the service life of the device. The heat dissipation box effectively dissipates heat, ensuring stable operation of the dual-shaft motor over a long period. The dust collection plate, in conjunction with the cleaning brush, improves dust collection efficiency and reduces omissions. The setting of limit posts ensures the stability of the moving plate's trajectory.
[0018] 2. This utility model achieves timed lubrication of the rotating shaft of the electric revolving door in the hot and cold aisles of the machine room through the cooperation of components such as the oil tank, oil delivery pipe, and support plate in the rotating shaft lubrication device, reducing friction and extending the service life of the rotating shaft. A micro motor drives an oil pump to deliver lubricating oil through the oil delivery pipe to the drip pipe, precisely dripping it into the rotating shaft, avoiding waste and ensuring lubrication effect. The fixing plate enhances the stability of the oil delivery pipe, preventing oil circuit blockage and improving the reliability of the lubrication system. The oil inlet at the top of the oil tank facilitates the addition of lubricating oil, and the reasonable arrangement of the number and position of the drip pipes ensures uniform distribution of lubricating oil. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of this utility model and these drawings without any creative effort.
[0020] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional side view structural schematic diagram of the present invention; Figure 3 This is a three-dimensional enlarged structural schematic diagram of the dust collection and cleaning device of this utility model; Figure 4 This is a three-dimensional cross-sectional structural diagram of the dust collection and cleaning device of this utility model; Figure 5 This is a three-dimensional enlarged structural schematic diagram of the shaft lubrication device of this utility model.
[0021] In the diagram: 1. Hot aisle; 2. Front aisle door; 3. Rear aisle door; 4. Dust collection and cleaning device; 401. Collection box; 402. Dual-shaft motor; 403. Threaded rod; 404. Threaded sleeve; 405. Moving plate; 406. Cleaning brush; 407. Limiting post; 408. Ash collection trough; 409. Ash pickup plate; 410. Fan; 411. Heat dissipation box; 412. Dust collection box; 5. Buffer spring; 6. Buffer pad; 7. Ash baffle plate; 8. Shaft lubrication device; 801. Oil tank; 802. Oil supply pipe; 803. Support plate; 804. Micro motor; 805. Oil pump; 806. Oil drip pipe; 807. Fixing plate. Detailed Implementation
[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit its scope.
[0023] To keep the drawings concise, only the parts relevant to the utility model are shown schematically in each drawing; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of the components with the same structure or function is schematically shown, or only one is labeled. In this document, "a" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."
[0024] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0026] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0027] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0028] like Figures 1-5 As shown, it illustrates an electric revolving door for hot and cold passages in a computer room according to an embodiment of the present invention, including a hot passage 1, a front passage door 2 at the bottom of the hot passage 1, a rear passage door 3 at the bottom of the hot passage 1, and a dust collection and cleaning device 4 at the bottom of the front passage door 2.
[0029] The dust collection and cleaning device 4 includes a collection box 401. The bottom of the collection box 401 is fixedly connected to the bottom of the front passage door 2. A dual-output shaft motor 402 is fixedly connected to the side of the collection box 401. A threaded rod 403 is fixedly connected to the output shaft of the dual-output shaft motor 402. A threaded sleeve 404 is threadedly connected to the circumferential surface of the threaded rod 403. A movable plate 405 is fixedly connected to the circumferential surface of the threaded sleeve 404. A cleaning brush 406 is fixedly connected to the bottom of the movable plate 405. A limit post 407 is fixedly connected to the inner wall of the collection box 401. A dust collection trough 408 is opened on the top of the collection box 401. A dust collection plate 409 is fixedly connected to the inner wall of the dust collection trough 408. A fan 410 is fixedly connected to the end of the dual-output shaft motor 402 away from the threaded rod 403. A heat dissipation box 411 is fixedly connected to the side of the collection box 401. A dust collection box 412 is fixedly connected through the side of the collection box 401.
[0030] In some examples, a buffer spring 5 is fixedly connected to the inner wall of the collection box 401, and a buffer pad 6 is fixedly connected to the end of the buffer spring 5 away from the collection box 401. A dust baffle 7 is fixedly connected to the inner wall of the collection box 401. Its function is to improve the service life of the buffer pad 6. At the same time, the buffer pad 6 can block the dust for a second time, preventing the dust from entering the threaded rod 403 and increasing wear, and further improving the dust collection effect.
[0031] The side of the buffer pad 6 is located on the displacement trajectory of the side of the moving plate 405. There are two buffer springs 5 and two buffer pads 6, which are symmetrically distributed along the vertical central axis of the collection box 401. Their function is to buffer the moving plate 405, prevent the moving plate 405 from hitting the inner wall of the collection box 401 due to excessive moving speed, and prevent damage to the moving plate 405 and the collection box 401, thereby improving the service life of the dust collection and cleaning device 4.
[0032] The heat sink 411 has several through holes on one side and an exhaust groove on the other side. The dual-shaft motor 402 is located inside the heat sink 411. Its function is to effectively dissipate heat through the through holes and exhaust groove, prevent the motor from overheating, ensure the motor runs stably for a long time, and extend the service life of the equipment.
[0033] The bottom of the cleaning brush 406 is slidably connected to the inner bottom of the collection box 401, and the side of the moving plate 405 is slidably connected to the side of the dust collection plate 409. Its function is to ensure that the cleaning brush 406 can effectively scrape off and collect dust during the movement, and the dust collection plate 409 works in sync to improve dust collection efficiency, reduce omissions, and ensure the efficient operation of the device.
[0034] The side of the movable plate 405 is slidably connected to the circumferential surface of the limiting post 407. There are two dust collection plates 409, which are symmetrically distributed along the vertical central axis of the collection box 401. Their function is to effectively guide the trajectory of the movable plate 405 during movement, avoid deviation, ensure that the dust collection plates 409 are evenly stressed and work together, and further improve the accuracy of dust collection and the overall stability of the device.
[0035] For example, such as Figures 1-5 As shown, during use, when a person passes through the front passage door 2, dust from their feet falls into the collection box 401. At this time, the user starts the dual-output shaft motor 402. The output shaft of the dual-output shaft motor 402 drives the threaded rod 403 to rotate. When the threaded rod 403 rotates, the threaded sleeve 404 connected to its circumferential surface is pushed by the thread, causing the moving plate 405 to slide along the circumferential surface of the limiting post 407. At this time, the cleaning brush 406 at the bottom of the moving plate 405 moves accordingly, scraping away the dust at the bottom of the collection box 401 and passing it through the dust collection trough 408. Upon entering the collection box 401, the end of the dual-shaft motor 402 away from the threaded rod 403 drives the fan 410 to rotate, generating airflow. The airflow enters the heat dissipation box 411 through the through hole on the side of the heat dissipation box 411, cooling the dual-shaft motor 402. The cooled gas is discharged through the exhaust groove, ensuring that the dual-shaft motor 402 operates stably for a long time. During the movement of the moving plate 405, the buffer spring 5 and the buffer pad 6 buffer the moving plate 405 to prevent the moving plate 405 from hitting the inner wall of the collection box 401 due to excessive movement speed.
[0036] like Figures 1-5 As shown, this invention illustrates an electric revolving door for hot and cold aisles in a computer room, comprising a rotating shaft lubrication device 8 installed at the top of the front aisle door 2. The rotating shaft lubrication device 8 includes an oil tank 801, which is fixedly connected to the top of the front aisle door 2. An oil supply pipe 802 is fixedly connected through and to the side of the oil tank 801. A support plate 803 is fixedly connected to the top of the front aisle door 2, and a micro motor 804 is fixedly connected to the top of the support plate 803. An oil pump 805 is fixedly connected to the output shaft of the micro motor 804. An oil dripping pipe 806 is fixedly connected through and to the circumference of the oil supply pipe 802. Its function is to drive the oil pump 805 through the micro motor 804 to deliver lubricating oil through the oil supply pipe 802 to the oil dripping pipe 806, which drips onto the rotating shaft at regular intervals, reducing friction, extending the service life of the rotating shaft, and ensuring the smooth operation of the revolving door.
[0037] In some examples, a fixing plate 807 is fixedly connected to the end of the oil supply pipe 802 away from the oil tank 801. The interior of the oil pump 805 penetrates and is fixedly connected to the circumferential surface of the oil supply pipe 802. Its function is to ensure that the oil pump 805 supplies oil stably. The fixing plate 807 enhances the stability of the oil supply pipe 802, avoids oil circuit blockage, improves the reliability of the lubrication system, and further ensures the smooth operation and long-term stability of the revolving door.
[0038] The top of the oil tank 801 has an oil inlet, and the oil drip pipe 806 is located directly above the pivot of the front passage door 2. Its function is to facilitate the precise dripping of lubricating oil into the pivot, avoid waste, ensure lubrication effect, and improve the smooth operation and service life of the revolving door.
[0039] There are two oil drip pipes 806, which are symmetrically distributed along the vertical central axis of the front passage door 2. The side section of the oil supply pipe 802 is set in a U-shape. Its function is to enhance the pressure resistance of the oil supply pipe 802, optimize the oil circuit circulation, ensure the uniform distribution of lubricating oil, further reduce the wear of the rotating shaft, and improve the overall operating efficiency and durability of the revolving door.
[0040] For example, such as 1~ Figure 5 As shown, during use, lubricating oil is periodically injected into the oil tank 801 through the oil inlet at the top of the oil tank 801. When it is necessary to lubricate the rotating shaft of the front passage door 2, the micro motor 804 is started. The output shaft of the micro motor 804 drives the oil pump 805 to rotate. The oil pump 805 delivers the lubricating oil in the oil tank 801 to the oil dripping pipe 806 through the oil delivery pipe 802. Then, the oil dripping pipe 806 drips the lubricating oil into the rotating shaft at regular intervals to lubricate the rotating shaft, reduce the friction of the rotating shaft during rotation, and increase its durability.
[0041] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.
Claims
1. An electric revolving door for hot and cold aisles in a computer room, characterized in that, include: A hot channel (1) is provided with a front channel door (2) at the bottom of the hot channel (1) and a rear channel door (3) at the bottom of the hot channel (1). A dust collection and cleaning device (4) is provided at the bottom of the front channel door (2). The dust collection and cleaning device (4) includes a collection box (401), the bottom of which is fixedly connected to the bottom of the front passage door (2). A dual-output shaft motor (402) is fixedly connected to the side of the collection box (401). A threaded rod (403) is fixedly connected to the output shaft of the dual-output shaft motor (402). A threaded sleeve (404) is threadedly connected to the circumferential surface of the threaded rod (403). A movable plate (405) is fixedly connected to the circumferential surface of the threaded sleeve (404). A cleaning device is fixedly connected to the bottom of the movable plate (405). A cleaning brush (406) is provided. A limiting post (407) is fixedly connected to the inner wall of the collection box (401). A dust collection trough (408) is provided on the top of the collection box (401). A dust collection plate (409) is fixedly connected to the inner wall of the dust collection trough (408). A fan (410) is fixedly connected to one end of the dual-shaft motor (402) away from the threaded rod (403). A heat dissipation box (411) is fixedly connected to the side of the collection box (401). A dust collection box (412) is fixedly connected through the side of the collection box (401).
2. The electric revolving door for hot and cold aisles in a computer room according to claim 1, characterized in that, A buffer spring (5) is fixedly connected to the inner wall of the collection box (401), and a buffer pad (6) is fixedly connected to the end of the buffer spring (5) away from the collection box (401). A dust baffle (7) is fixedly connected to the inner wall of the collection box (401).
3. The electric revolving door for hot and cold aisles in a computer room according to claim 2, characterized in that, The side of the buffer pad (6) is located on the displacement trajectory of the side of the moving plate (405). There are two buffer springs (5) and buffer pads (6), which are symmetrically distributed along the vertical central axis of the collection box (401).
4. The electric revolving door for hot and cold aisles in a computer room according to claim 3, characterized in that, The heat sink (411) has several through holes on one side and an exhaust groove on the other side. The dual-shaft motor (402) is located inside the heat sink (411).
5. The electric revolving door for hot and cold aisles in a computer room according to claim 4, characterized in that, The bottom of the cleaning brush (406) is slidably connected to the inner bottom of the collection box (401), and the side of the moving plate (405) is slidably connected to the side of the dust collection plate (409).
6. The electric revolving door for hot and cold aisles in a computer room according to claim 5, characterized in that, The side of the movable plate (405) is slidably connected to the circumferential surface of the limiting post (407), and there are two ash-collecting plates (409) which are symmetrically distributed along the vertical central axis of the collection box (401).
7. An electric revolving door for hot and cold aisles in a computer room according to claim 6, characterized in that, The top of the front passage door (2) is provided with a rotating shaft lubrication device (8). The rotating shaft lubrication device (8) includes an oil tank (801). The oil tank (801) is fixedly connected to the top of the front passage door (2). An oil supply pipe (802) is fixedly connected through the side of the oil tank (801). A support plate (803) is fixedly connected to the top of the front passage door (2). A micro motor (804) is fixedly connected to the top of the support plate (803). An oil pump (805) is fixedly connected to the output shaft of the micro motor (804). An oil drip pipe (806) is fixedly connected through the circumference of the oil supply pipe (802).
8. The electric revolving door for hot and cold aisles in a computer room according to claim 7, characterized in that, A fixing plate (807) is fixedly connected to one end of the oil pipeline (802) away from the oil tank (801), and the interior of the oil pump (805) penetrates and is fixedly connected to the circumferential surface of the oil pipeline (802).
9. An electric revolving door for hot and cold aisles in a computer room according to claim 8, characterized in that, The top of the oil tank (801) is provided with an oil inlet, and the oil drip pipe (806) is located directly above the pivot of the front passage door (2).
10. An electric revolving door for hot and cold aisles in a computer room according to claim 9, characterized in that, The number of the oil dripping pipes (806) is set to two, and they are symmetrically distributed along the vertical central axis of the front passage door (2). The side cross section of the oil delivery pipe (802) is set to a concave shape.