360-degree rotatable cam hydraulic door closer for narrow frame door

Abstract

To provide a 360-degree rotatable cam hydraulic door closer for narrow frame doors.SOLUTION: A camshaft is supported in a door closer housing 100 so as to rotatable 360 degrees, and through interaction between a damping roller 310 that is rotatably installed on a bidirectional piston 300 and a left closing arc groove and a right closing arc groove that are installed on the outer circumferential surface of the eccentric cam 210, it is realized that the door is kept closed when it is rotated 0, 180, or 360 degrees. At this time, the damping roller 310 is fitted into the left closing arc groove or the right closing arc groove and is fixed relatively to the eccentric cam 210, thereby achieving the effect of positioning the door opening and closing angle and finally stopping the door. At the same time, during the process of the camshaft rotating in the door closer housing 100, the damping roller 310 is subjected to the damping action of the eccentric cam 210, so that the instantaneous speed when the door is opened or closed is reduced and sufficient buffering is provided.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to the technical field of door closers, and particularly to a cam hydraulic door closer that can rotate 360 degrees for narrow-edge doors.

Background Art

[0002] A door closer is a hydraulic device such as a spring provided at the upper part of a door. After the door is opened, it is compressed and released to automatically close the door, having the function of a spring door. After the door is opened, it is ensured that the door can be accurately and timely closed to the initial position.

[0003] During the process of the spring being released, in the door closer, the hydraulic oil in the left chamber of the door closer is compressed and the check valve is closed. The hydraulic oil flows out through the gap between the door closer housing and the plunger, and returns to the right chamber through two flow paths provided with small holes in the plunger and the throttle valve core. Therefore, the hydraulic oil becomes the resistance for the spring to be released, and the cushion effect by throttling is obtained, and the closing speed of the door is controlled.

[0004] Most common door closers only allow the door to be opened up to 90 degrees. A few allow the door to be opened up to 180 degrees. Therefore, the above-mentioned door closers cannot be used when the door needs to be opened and closed more than 180 degrees, and their application range is narrow. They cannot be applied to doors that can be entered and exited from both sides, and their use is restricted.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide a cam hydraulic door closer that can rotate 360 degrees for narrow-edge doors, and to solve the technical problems of conventional door closers with a narrow application range and inability to be applied to doors that can be entered and exited from both sides.

Means for Solving the Problems

[0006] To achieve the above object, the 360-degree rotatable cam hydraulic door closer for a narrow-edge door according to an embodiment of the present invention includes a door closer housing, a camshaft, a bidirectional piston, and a driving spring. Inside the door closer housing, a lumen is formed along its axial direction. The camshaft has an axial direction perpendicular to the extension direction of the door closer housing, is supported in the door closer housing so as to be rotatable 360 degrees, and an eccentric cam that can rotate synchronously at the center is installed. The bidirectional piston is slidably provided in the lumen, is located on the right side of the eccentric cam, and a damping roller is rotatably provided on the side close to the eccentric cam. The driving spring is housed in the lumen, abuts against the bidirectional piston and the door closer housing respectively, and biases so that the damping roller always softly abuts against the outer peripheral surface of the eccentric cam. On the outer peripheral surface of the eccentric cam, a left closing arc-shaped groove, an upper damping convex portion, a right closing arc-shaped groove, and a lower damping convex portion are sequentially installed along the clockwise direction. The left closing arc-shaped groove and the right closing arc-shaped groove are located on the same horizontal line, and the upper damping convex portion and the lower damping convex portion are located on the same vertical line.

[0007] Preferably, a fixing pin is provided on the side of the bidirectional piston close to the eccentric cam. The damping roller is rotatably attached to the fixing pin.

[0008] Preferably, the driving spring includes an inner spring and an outer spring. The outer spring covers the outside of the inner spring. One end of the outer spring and the inner spring simultaneously abuts against the door closer housing, and the other end of the outer spring and the inner spring simultaneously abuts against the bidirectional piston.

[0009] Preferably, a first bearing cylinder is installed at a position corresponding to the lower end of the camshaft, a position-limiting mounting seat is installed at a position corresponding to the upper end of the camshaft, a second bearing cylinder is installed on the position-limiting mounting seat, the midpoints of the first bearing cylinder and the second bearing cylinder are located on the same axis, and the camshaft is provided to penetrate through the first bearing cylinder and the second bearing cylinder.

[0010] Preferably, an outer peripheral seal ring is installed between the outer end face of the position-limiting mounting seat and the door closer housing, and an inner peripheral seal ring is installed between the inner end face of the position-limiting mounting seat and the camshaft.

[0011] Preferably, the door closer housing includes a housing body and a sealed end cover. The housing body is hollow inside and open on both sides, and the camshaft is rotatably connected to the housing body. There are two sealed end covers, which are respectively installed at the openings on both sides of the housing body, and surround each other to form the inner cavity. An end cover seal ring is installed between the outer end face of the sealed end cover and the housing body.

[0012] Preferably, an automatic compensation valve assembly is further provided, which is slidably installed in the inner cavity and located on the left side of the eccentric cam. The inner cavity is partitioned by the automatic compensation valve assembly and the bidirectional piston, and a first oil passage located on the left side of the automatic compensation valve assembly, a second oil passage located on the right side of the bidirectional piston, and a third oil passage located between the automatic compensation valve assembly and the bidirectional piston are formed. The first oil passage, the second oil passage, and the third oil passage are all filled with hydraulic oil, and the hydraulic oil in the second oil passage and the third oil passage is communicated through the bidirectional piston. When the pressure in the first oil passage exceeds a predetermined threshold value, the automatic compensation valve assembly is configured to permit the flow of hydraulic oil between the first oil passage and the third oil passage.

[0013] Preferably, the automatic compensation valve assembly includes a valve piston, a valve body, a valve core member, and a core spring. The valve piston is slidably provided in the inner cavity. The valve body is mounted in the valve piston, and valve flow paths communicating with the first oil passage and the third oil passage are respectively provided therethrough. The valve core member is movably provided in the valve flow path and is used to realize the opening or blocking of the valve flow path. The core spring is accommodated in the valve flow path, one end is connected to the valve body, the other end is connected to the valve core member, and biases the valve core member to block the valve flow path.

[0014] One or more of the above-described means of the 360-degree rotatable cam hydraulic door closer for a narrow-edge door according to the present invention have at least one of the following technical effects. This 360-degree rotatable cam hydraulic door closer for a narrow-edge door has a novel structure. The camshaft is supported in the door closer housing so as to be rotatable 360 degrees, and is rotatably installed on a damping roller installed on a bi-directional piston. By the interaction with a left closing arc-shaped groove and a right closing arc-shaped groove installed on the outer peripheral surface of the eccentric cam, when the door is rotated to 0 degrees, 180 degrees, or 360 degrees, the closed state is maintained. At this time, the damping roller is fitted into the left closing arc-shaped groove or the right closing arc-shaped groove and is fixed relative to the eccentric cam. Thereby, the eccentric cam is prevented from continuously rotating in the door closer housing, achieving a positioning effect with respect to the opening and closing angle of the door and finally stopping the door. At the same time, during the process of the camshaft rotating in the door closer housing, the damping roller receives a damping effect on the eccentric cam, reducing the instantaneous speed when the door is opened and closed and performing sufficient buffering. In this way, the present invention realizes an opening of up to 360 degrees, meets the usage needs of a rotating door, and is convenient for the door to open on both sides.

[0015] To more clearly explain the technical aspects in the embodiments of the present invention, the drawings required in the following description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings from these drawings without creative efforts.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail. Examples of the embodiments are shown in the drawings. Here, the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are exemplary for explaining the embodiments of the invention and should not be construed as a limitation on the present invention.

[0018] In the description of the embodiments of the present invention, the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is the orientation or positional relationship shown based on the drawings, and is for the purpose of explaining and simplifying the description of the embodiments of the present invention, and does not indicate or imply that the device or member needs to have a specific orientation and be constructed and operate in a specific orientation, so it should not be construed as a limitation on the present invention.

[0019] Furthermore, the terms "first" and "second" are used for the purpose of description and should not be construed as indicating or implying relative importance or the number of technical features. Therefore, the features defined as "first" and "second" explicitly or implicitly include one or more features. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

[0020] In the embodiments of the present invention, terms such as "attachment", "connected to each other", "connection", "fixation", etc. should be understood broadly unless otherwise specifically defined. For example, a fixed connection may be a detachable connection or an integral one, may be a mechanical connection or an electrical connection, may be a direct connection or an indirect connection via an intermediate medium, may also be a communication inside two members or an interaction between two members. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present invention based on the specific situations.

[0021] (First Embodiment) In the first embodiment of the present invention, as shown in FIGS. 1 to 3, a 360-degree rotatable cam hydraulic door closer for a narrow-edge door includes a door closer housing 100, a camshaft 200, a bidirectional piston 300, and a driving spring 400.

[0022] Inside the door closer housing 100, a cavity 110 is formed along its axial direction.

[0023] The camshaft 200 has an axial direction perpendicular to the extension direction of the door closer housing 100, is supported in the door closer housing 100 so as to be rotatable 360 degrees, and an eccentric cam 210 that can rotate synchronously at the center is installed.

[0024] The bidirectional piston 300 is slidably provided in the cavity 110, is located on the right side of the eccentric cam 210, and a damping roller 310 is rotatably provided on the side close to the eccentric cam 210.

[0025] The driving spring 400 is accommodated in the cavity 110, abuts against the bidirectional piston 300 and the door closer housing 100 respectively, and biases so that the damping roller always softly abuts against the outer peripheral surface of the eccentric cam.

[0026] On the outer peripheral surface of the eccentric cam 210, a left closed arc-shaped groove 220, an upper damping convex portion 230, a right closed arc-shaped groove 240, and a lower damping convex portion 250 are sequentially installed along the clockwise direction. The left closed arc-shaped groove 220 and the right closed arc-shaped groove 240 are located on the same horizontal line. The upper damping convex portion 230 and the lower damping convex portion 250 are located on the same vertical line.

[0027] Specifically, in this embodiment, this cam hydraulic door closer for a narrow bezel door that can rotate 360 degrees has a novel structure. The camshaft 200 is supported in the door closer housing 100 so as to be rotatable 360 degrees, and is rotatably installed on the bi-directional piston 300 with a damping roller 310. By the interaction between the left closed arc-shaped groove 220 and the right closed arc-shaped groove 240 installed on the outer peripheral surface of the eccentric cam 210, when the door is rotated to 0 degrees, 180 degrees, and 360 degrees, the closed state is maintained. At this time, the damping roller 310 is fitted into the left closed arc-shaped groove 220 or the right closed arc-shaped groove 240 and is fixed relative to the eccentric cam 210. Thereby, the eccentric cam 210 is prevented from continuously rotating in the door closer housing 100, achieving a positioning effect with respect to the opening and closing angle of the door, and finally stopping the door. At the same time, during the process of the camshaft 200 rotating in the door closer housing 100, the damping roller 310 receives a damping effect on the eccentric cam 210, reducing the instantaneous speed when the door is opened and closed, and sufficient buffering is performed. In this way, the present invention realizes an opening from 0 degrees to 360 degrees, meets the usage needs of a rotating door, and is convenient for the door to open on both sides.

[0028] (Second Embodiment) In the second embodiment of the present invention, as shown in FIGS. 1 to 3, on the side of the bi-directional piston 300 close to the eccentric cam 210, a fixed pin 320 is provided. The damping roller 310 is rotatably attached to the fixed pin 320.

[0029] Specifically, in this embodiment, the damping roller 310 is rotatably attached to the bi-directional piston 300 via a fixed pin 320, facilitating the attachment and detachment of the damping roller 310 and enabling easy maintenance or replacement of the damping roller 310.

[0030] Other parts of this embodiment are the same as those of the first embodiment. For features not described in this embodiment, the interpretation of the first embodiment is applied, and the description is omitted here.

[0031] (Third Embodiment) In the third embodiment of the present invention, as shown in FIGS. 1 - 2, the driving spring 400 includes an inner spring 410 and an outer spring 420. The outer spring 420 is sleeved outside the inner spring 410. One end of the outer spring 420 and the inner spring 410 simultaneously abuts against the door closer housing 100. The other end of the outer spring 420 and the inner spring 410 simultaneously abuts against the bi-directional piston 300.

[0032] Specifically, in this embodiment, the driving spring 400 has a simple structure and a reasonable design. When the driving spring 400 is stretched or contracted under force, both the inner spring 410 and the outer spring 420 stretch or contract accordingly without interfering with each other. Therefore, when the inner spring 410 and the outer spring 420 are used in combination, deformation is less likely to occur, effectively enhancing the service life of the inner spring 410 and the outer spring 420. Due to the composite design, the elasticity of the driving spring 400 is significantly improved, ensuring the verticality and stability of the spring force. Also, it can effectively prevent the inner spring 410 and the outer spring 420 from being damaged due to excessive load.

[0033] Other parts of this embodiment are the same as those of the first embodiment. For features not described in this embodiment, the interpretation of the first embodiment is applied, and the description is omitted here.

[0034] (Fourth Embodiment) In the fourth embodiment of the present invention, as shown in FIG. 1, a first bearing cylinder 120 is installed at a position corresponding to the lower end of the camshaft 200, and a position-limiting mounting seat 130 is installed at a position corresponding to the upper end of the camshaft 200. A second bearing cylinder 140 is installed on the position-limiting mounting seat 130. The midpoints of the first bearing cylinder 120 and the second bearing cylinder 140 are located on the same axis. The camshaft 200 is provided to penetrate through the first bearing cylinder 120 and the second bearing cylinder 140.

[0035] Specifically, in this embodiment, the first bearing cylinder 120 and the second bearing cylinder 140 mainly serve to fix the camshaft 200. The first bearing cylinder 120 and the second bearing cylinder 140 serve to reduce the vibration when the camshaft 200 moves, maintain the balance and stability of the camshaft 200, reduce friction and wear, and extend the service life of the camshaft 200.

[0036] Other parts of this embodiment are the same as those of the first embodiment. For the features not described in this embodiment, the interpretation of the first embodiment is applicable, and the description is omitted here.

[0037] (Fifth Embodiment) In the fifth embodiment of the present invention, as shown in FIG. 1, an outer peripheral seal ring 500 is installed between the outer end face of the position-limiting mounting seat 130 and the door closer housing 100. An inner peripheral seal ring 600 is installed between the inner end face of the position-limiting mounting seat 130 and the camshaft 200.

[0038] Specifically, in this embodiment, on the one hand, the outer peripheral seal ring 500 always tightly abuts against the outer end face of the position-limiting mounting seat 130 and the door closer housing 100 respectively, and can seal the space between the position-limiting mounting seat 130 and the door closer housing 100. On the other hand, the inner peripheral seal ring 600 always tightly abuts against the inner end face of the position-limiting mounting seat 130 and the camshaft 200 respectively, and can seal the space between the position-limiting mounting seat 130 and the camshaft 200.

[0039] Other parts of this embodiment are the same as those of the fourth embodiment. For features not described in this embodiment, the interpretation of the fourth embodiment shall apply, and the description thereof is omitted herein.

[0040] (Sixth Embodiment) In the sixth embodiment of the present invention, as shown in FIG. 4, the door closer housing 100 includes a housing body 150 and a sealing end cover 160.

[0041] The housing body 150 has a hollow interior and both sides are open, and a camshaft 200 is rotatably connected to the housing body 150.

[0042] There are two sealing end covers 160, which are respectively installed at the openings on both sides of the housing body 150, and surround each other to form an inner cavity 110. An end cover seal ring 170 is installed between the outer end face of the sealing end cover 160 and the housing body 150.

[0043] Specifically, in this embodiment, the housing body 150 and the two sealing end covers 160 in the door closer housing 100 are detachably connected. On the one hand, the operability of maintaining the entire 360-degree rotatable cam hydraulic door closer for a narrow-edge door becomes extremely easy, and the operator can disassemble and maintain it quickly and conveniently. On the other hand, the detachable structure makes it easy to maintain or replace the single housing body 150 or the sealing end cover 160, and the maintenance cost can be reduced.

[0044] Other parts of this embodiment are the same as those of the first embodiment. For features not described in this embodiment, the interpretation of the first embodiment shall apply, and the description thereof is omitted herein.

[0045] (Seventh Embodiment) In the seventh embodiment of the present invention, as shown in FIGS. 1 to 2, a 360-degree rotatable cam hydraulic door closer for a narrow-edge door further includes an automatic compensation valve assembly 700 that is slidably installed in the inner cavity 110 and is located on the left side of the eccentric cam 210. The inner cavity 110 is partitioned by the automatic compensation valve assembly 700 and the bidirectional piston 300, and a first oil passage 810 located on the left side of the automatic compensation valve assembly 700, a second oil passage 820 located on the right side of the bidirectional piston 300, and a third oil passage 830 located between the automatic compensation valve assembly 700 and the bidirectional piston 300 are formed. The first oil passage 810, the second oil passage 820, and the third oil passage 830 are all filled with hydraulic oil. The hydraulic oil in the second oil passage 820 and the third oil passage 830 is communicated through the bidirectional piston 300. The automatic compensation valve assembly 700 is configured to allow the flow of hydraulic oil between the first oil passage 810 and the third oil passage 830 when the pressure in the first oil passage 810 exceeds a predetermined threshold value.

[0046] Specifically, in this embodiment, the first oil passage 810, the second oil passage 820, and the third oil passage 830 are all filled with hydraulic oil. As the door closer housing 100 rotates with the rotation of the door body, the position of the bidirectional piston 300 in the camshaft 200 changes. As a result, the volume of the second oil passage 820 changes, the hydraulic oil in the second oil passage 820 and the third oil passage 830 flows, a pressure difference is generated between the first oil passage 810 and the third oil passage 830, and the state of the automatic compensation valve assembly 700 changes. Therefore, the hydraulic oil flows between the first oil passage 810 and the third oil passage 830, and the balance of the pressure difference between the first oil passage 810 and the third oil passage 830 is maintained. That is, the flow of the hydraulic oil in the first oil passage 810, the second oil passage 820, and the third oil passage 830 can be adjusted according to the movement of the door body.

[0047] Other parts of this embodiment are the same as those of the first embodiment. For the features not described in this embodiment, the interpretation of the first embodiment shall apply, and the description is omitted here.

[0048] (Eighth Embodiment) In the eighth embodiment of the present invention, as shown in FIG. 5, the automatic compensation valve assembly 700 includes a valve piston 710, a valve body 720, a valve core member 730, and a core spring 740.

[0049] The valve piston 710 is slidably provided in the inner cavity 110.

[0050] The valve body 720 is attached inside the valve piston 710, and a valve flow path 721 communicating with the first oil path 810 and the third oil path 830 is provided therethrough.

[0051] The valve core member 730 is movably provided in the valve flow path 721 and is used to realize the opening or blocking of the valve flow path 721.

[0052] The core spring 740 is accommodated in the valve flow path 721, one end is connected to the valve body 720, the other end is connected to the valve core member 730, and biases the valve core member 730 to block the valve flow path 721.

[0053] Specifically, in this embodiment, the movement of the valve core member 730 realizes the opening or blocking of the valve flow path 721. The installation of the core spring 740 ensures the accuracy of the movement of the valve core member 730. When a pressure difference occurs between the first oil path 810 and the third oil path 830, the valve core member 730 pushed by the hydraulic pressure moves in the valve flow path 721 while overcoming the elastic force of the core spring 740 to open the valve flow path 721. When the pressure difference between the first oil path 810 and the third oil path 830 is balanced, the valve core member 730 is pushed by the elastic force of the core spring 740, moves in the valve flow path 721, returns to its original position, and blocks the valve flow path 721. The state of the automatic compensation valve assembly 700 changes automatically and has high reliability.

[0054] Other parts of this embodiment are the same as those of the seventh embodiment. For features not described in this embodiment, the interpretation of the seventh embodiment shall apply, and the description thereof is omitted here.

[0055] The above are only preferred embodiments of the present invention, and do not limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle scope of the present invention shall all be included within the protection scope of the present invention.

Description of Reference Numerals

[0056] 100 Door closer housing 110 Inner cavity body 120 First bearing cylinder 130 Position limiting mounting seat 140 Second bearing cylinder 150 Housing body 160 Sealed end cover 170 End cover seal ring 200 Camshaft 210 Eccentric cam 220 Left closed arc-shaped groove 230 Upper damping convex part 240 Right closed arc-shaped groove 250 Lower damping convex part 300 Bi-directional piston 310 Damping roller 320 Fixed pin 400 Driving spring 410 Inner spring 420 Outer spring 500 Outer peripheral seal ring 600 Inner peripheral seal ring 700 Automatic compensation valve assembly 710 Valve piston 720 Valve body 721 Valve flow path 733 Valve core member 740 Core spring 810 First oil path 820 Second oil path 830 Third oil path

Claims

1. A cam hydraulic door closer capable of rotating 360 degrees for narrow frame doors, Includes a door closer housing, a camshaft, a bidirectional piston, and a drive spring; An inner cavity is formed in the door closer housing along its axial direction, The camshaft has an axial direction perpendicular to the extension direction of the door closer housing, is supported in the door closer housing so as to be rotatable 360 ​​degrees, and has an eccentric cam installed in the center, which can rotate synchronously. The bidirectional piston is slidably mounted in the bore body and is located to the right of the eccentric cam, and a damping roller is rotatably mounted on the side closer to the eccentric cam, The drive spring is accommodated in the inner cavity body and abuts against the bidirectional piston and the door closer housing, respectively, and biases the damping roller so as to always flexibly abut against the outer circumferential surface of the eccentric cam; The outer circumferential surface of the eccentric cam is provided with a left closing arc groove, an upper damping protrusion, a right closing arc groove, and a lower damping protrusion in the clockwise direction, the left closing arc groove and the right closing arc groove being located on the same horizontal line, and the upper damping protrusion and the lower damping protrusion being located on the same vertical line. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

2. 2. The cam hydraulic door closer for narrow frame doors capable of 360 degree rotation according to claim 1, The bidirectional piston is provided with a fixed pin on a side closer to the eccentric cam, The damping roller is rotatably mounted on the fixed pin. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

3. 2. The cam hydraulic door closer for narrow frame doors capable of 360 degree rotation according to claim 1, The drive spring includes an inner spring and an outer spring, the outer spring is placed on the outside of the inner spring, one ends of the outer spring and the inner spring simultaneously abut against the door closer housing, and the other ends of the outer spring and the inner spring simultaneously abut against the bidirectional piston. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

4. 2. The cam hydraulic door closer for narrow frame doors capable of 360 degree rotation according to claim 1, The door closer housing has a first bearing sleeve installed at a position corresponding to a lower end of the camshaft, a position limiting mounting seat installed at a position corresponding to an upper end of the camshaft, a second bearing sleeve installed on the position limiting mounting seat, the midpoints of the first bearing sleeve and the second bearing sleeve are located on the same axis, and the camshaft is provided to pass through the first bearing sleeve and the second bearing sleeve. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

5. 5. The 360 ​​degree rotatable cam hydraulic door closer for narrow frame doors according to claim 4, An outer circumferential seal ring is installed between the outer end surface of the position limiting mounting seat and the door closer housing, and an inner circumferential seal ring is installed between the inner end surface of the position limiting mounting seat and the camshaft. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

6. 2. The cam hydraulic door closer for narrow frame doors capable of 360 degree rotation according to claim 1, The door closer housing includes a housing body and a sealed end cap; The housing body is hollow and has both sides open, and the camshaft is rotatably connected to the housing body. The two sealed end caps are provided at the openings on both sides of the housing body, and are fitted together to form the inner cavity. An end cap seal ring is provided between the outer end surface of the sealed end cap and the housing body. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

7. 2. The cam hydraulic door closer for narrow frame doors capable of 360 degree rotation according to claim 1, a self-compensating valve assembly slidably mounted within said bore and located to the left of said eccentric cam; the bore body is partitioned by the automatic compensation valve assembly and the bidirectional piston, and a first oil passage located on the left side of the automatic compensation valve assembly, a second oil passage located on the right side of the bidirectional piston, and a third oil passage located between the automatic compensation valve assembly and the bidirectional piston are formed in the bore body; the first oil passage, the second oil passage, and the third oil passage are all filled with hydraulic oil; and the hydraulic oil in the second oil passage and the third oil passage is communicated via the bidirectional piston; The automatic compensating valve assembly is configured such that when pressure in the first oil passage exceeds a predetermined threshold, the automatic compensating valve assembly allows hydraulic fluid flow between the first oil passage and the third oil passage. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

8. 8. The cam hydraulic door closer for narrow frame doors capable of 360 degree rotation according to claim 7, The self-compensating valve assembly includes a valve piston, a valve body, a valve core member, and a core spring; The valve piston is slidably disposed within the bore body, the valve body is attached in the valve piston, and has valve flow passages extending therethrough that communicate with the first oil passage and the third oil passage, respectively; The valve core member is movably disposed in the valve flow passage and is used to open or close the valve flow passage; The core spring is housed in the valve flow passage, has one end connected to the valve body, and the other end connected to the valve core member, and biases the valve core member to close the valve flow passage. This is a 360 degree rotatable cam hydraulic door closer for narrow frame doors.

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