Cam hydraulic door closer for narrow frame doors

Abstract

To provide, in particular, a cam hydraulic door closer for narrow frame doors relating to a technical field of a door closer.SOLUTION: The cam hydraulic door closer for narrow frame doors is built-in designed, including a door closer body, a horizontal fixing member, and a vertical fixing member fixed inside a door body by embedding. While the door closer body is fixed so that its position in the horizontal direction is regulated by the horizontal fixing member, it is fixed so that its position in the vertical direction is regulated by the vertical fixing member. As a result, the outer surfaces of the door closer body, the horizontal fixing member, and the vertical fixing member are flush with the door body, so that it does not take up extra space, does not spoil the aesthetics of the door, and the door closer body is not exposed and is not easily damaged, which ensures the usage performance and extends the life of this cam hydraulic door closer for narrow frame doors.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of door closers, and more particularly to a cam hydraulic door closer for narrow frame doors. [Background technology]

[0002] A door closer is a hydraulic device like a spring attached to the top of a door. After the door is opened, it compresses and opens to automatically close the door, acting like a spring door, ensuring that the door closes accurately and in a timely manner to its initial position. When the spring opens, the hydraulic oil in the left chamber of the door closer is compressed, closing the check valve. The hydraulic oil flows out through the gap between the door closer housing and the plunger and returns to the right chamber through two channels, one in the plunger and one in the throttle valve core. Therefore, the hydraulic oil acts as resistance to the opening of the spring, providing a cushioning effect through the throttle, controlling the speed at which the door closes.

[0003] Currently, door closers on the market are installed between the door and the door frame, and most are installed at the top of the door. This requires securing space for the door closer when installing the door itself. Furthermore, door closers that are exposed to the outside are prone to impacts, pressure, and other damage, reducing their usability. Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a cam hydraulic door closer for narrow frame doors, which solves the technical problems of conventional door closers that are attached to the top end of the door, require space for installation, and are prone to breakage. [Means for solving the problem]

[0005] To achieve the above-mentioned objectives, a cam hydraulic door closer for narrow frame doors according to an embodiment of the present invention is used to connect a door body and a door frame, and includes a door closer body, a horizontal fixing member, a vertical fixing member, and an eccentric cam shaft. The door closer body is embedded in a corner of the door body and is flush with the door body. The horizontal fixing member has one end fixed so as to be flush with the upper surface of the door closer body, and the other end extending horizontally and fixed so as to be flush with the horizontal edge of the door body. The vertical fixing member has one end fixed so as to be flush with the bottom surface of the door closer body, and the other end extending vertically and being flush with the left end surface of the door closer body, and at the same time being fixed so as to be flush with the vertical side of the door body. The eccentric camshaft has an axial direction perpendicular to the extension direction of the door closer body, one end of which is fixed and connected to the door frame, and the other end of which is rotatably connected inside the door closer body.

[0006] Preferably, the horizontal fixing member is installed in the shape of a straight line and includes a first door closer connection board and a first door body connection board which are integrally formed, the first door closer connection board being fixed flush with the upper surface of the door closer body by a plurality of fixing screws, and the first door body connection board being fixed flush with the horizontal edge of the door body by a plurality of fixing screws.

[0007] Preferably, the vertical fixing member is arranged in an L-shape and includes a second door closer connecting board and a second door body connecting board which are integrally formed. The second door closer connection board is installed horizontally and fixed flush with the bottom surface of the door closer body by a plurality of fixing screws. The second door body connection board is installed vertically, flush with the left end face of the door closer body, and fixed flush with the vertical side of the door body by a plurality of fixing screws.

[0008] Preferably, the door closer body comprises a door closer housing, an automatic compensating valve assembly, a damping compression assembly, and a drive spring member. The door closer housing has an inner cavity filled with hydraulic oil along its axial direction provided inside the door closer housing, and the eccentric camshaft is rotatably supported within the door closer housing. The self-compensating valve assembly is slidably mounted within the bore and is located to the left of the eccentric camshaft. The damping compression assembly is slidably mounted within the bore and is located to the right of the eccentric camshaft. The drive spring member is housed within the inner cavity and abuts against the damping and compression assembly and the door closer housing, respectively, and biases the damping and compression assembly so that it flexibly abuts against the outer peripheral surface of the eccentric camshaft.

[0009] Preferably, the inner cavity body is partitioned into the automatic compensating valve assembly and the damping compression assembly, and is formed with a first oil passage located on the left side of the automatic compensating valve assembly, a second oil passage located on the right side of the damping compression assembly, and a third oil passage located between the automatic compensating valve assembly and the damping compression assembly, and the second oil passage and the third oil passage are connected to each other. 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.

[0010] Preferably, the self-compensating valve assembly comprises a valve piston, a valve body, a valve core member, and a core spring. The valve piston is slidably disposed within the bore. The valve body is attached within the valve piston, and has valve passages extending therethrough that communicate with the first oil passage and the third oil passage, respectively. The valve core member is movably disposed within 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.

[0011] Preferably, the damping compression assembly comprises a compression piston, a fixed pin, and a damping roller. The compression piston is slidably disposed within the inner cavity body so that the drive spring member abuts against the compression piston and the door closer housing, respectively, and piston flow paths are provided therethrough that communicate with the second oil passage and the third oil passage, respectively. The fixed pin is fixed to the end of the compression piston that is closer to the eccentric camshaft. The damping roller is rotatably mounted on the fixed pin and flexibly contacts the outer peripheral surface of the eccentric camshaft.

[0012] Preferably, the drive spring member comprises an inner spring and an outer spring, the outer spring is placed over 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 damping compression assembly.

[0013]

[0006] The above-mentioned one or more means of the cam hydraulic door closer for narrow frame doors according to the present invention have at least one of the following technical effects: This cam hydraulic door closer for narrow frame doors has an embedded design, with the door closer body, horizontal fixing member, and vertical fixing member fixed inside the door body by a recessed installation method. The door closer body is fixed so that its horizontal position is restricted by the horizontal fixing member, and its vertical position is restricted by the vertical fixing member. This makes the outer surfaces of the door closer body, horizontal fixing member, and vertical fixing member flush with the door body, saving extra space, not damaging the aesthetics of the door, and preventing the door closer body from being exposed and damaging, thereby ensuring the usability and extending the service life of this cam hydraulic door closer for narrow frame doors.

[0014] In order to more clearly describe the technical aspects of the embodiments of the present invention, the following briefly describes the drawings required in the description of the embodiments or prior art. It is clear 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 explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing the internal structure of a cam hydraulic door closer for narrow frame doors according to an embodiment of the present invention. [Figure 2] FIG. 1 is a side view of a cam hydraulic door closer for narrow frame doors according to an embodiment of the present invention. [Figure 3] FIG. 1 is a plan view of a cam hydraulic door closer for narrow frame doors according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram illustrating the internal structure of an autocompensating valve assembly according to an embodiment of the present invention. FIG. [Figure 5] FIG. 2 is a schematic diagram illustrating the internal structure of a damped compression assembly according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016]

[0023] The following describes in detail the embodiments of the present invention. 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 merely illustrative for describing the embodiments of the invention and should not be construed as limitations on the present invention.

[0017] In describing the embodiments of the present invention, orientations or positional relationships indicated by terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" are orientations or positional relationships shown based on the drawings, and are intended to simplify the description and explanation of the embodiments of the present invention. They do not indicate or imply that a device or component must have a specific orientation or be constructed or operate in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes and should not be construed to express or imply the relative importance or number of technical features. Thus, a feature defined as "first" or "second" explicitly or implicitly includes one or more features. In describing embodiments of the present invention, "plurality" means two or more, unless expressly limited otherwise.

[0019] In the embodiments of the present invention, terms such as "attached," "connected to each other," "connected," and "fixed" should be broadly understood unless otherwise clearly specified. For example, they may refer to a fixed connection, a detachable connection, or an integral connection, or may be a mechanical connection or an electrical connection, or may be a direct connection or an indirect connection via an intermediate medium, or may refer to internal communication between two members or 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 specific circumstances.

[0020] (First embodiment) In a first embodiment of the present invention, as shown in Figures 1 to 3, a cam hydraulic door closer for narrow frame doors is used to connect a door body and a door frame, and includes a door closer body 100, a horizontal fixing member 200, a vertical fixing member 300, and an eccentric cam shaft 400.

[0021] The door closer body 100 is embedded in the corner of the door body and is flush with the door body.

[0022] The horizontal fixing member 200 is fixed so that one end is flush with the upper surface of the door closer body 100, and the other end extends horizontally and is fixed so that it is flush with the horizontal edge of the door body.

[0023] The vertical fixing member 300 is fixed so that one end is flush with the bottom surface of the door closer body 100, and the other end extends vertically and is flush with the left end surface of the door closer body 100, and is also fixed so that it is flush with the vertical side of the door body.

[0024] The eccentric camshaft 400 has an axial direction perpendicular to the extension direction of the door closer body 100, one end of which is fixed and connected to the door frame, and the other end of which is rotatably connected to the inside of the door closer body 100.

[0025] Specifically, in this embodiment, the cam hydraulic door closer for narrow frame doors has an embedded design, and the door closer main body 100, horizontal fixing member 200, and vertical fixing member 300 are fixed inside the door main body by an embedded installation method. Meanwhile, the horizontal fixing member 200 fixes the door closer main body 100 by regulating its position in the horizontal direction. Meanwhile, the vertical fixing member 300 fixes the door closer main body 100 by regulating its position in the vertical direction. As a result, the outer surfaces of the door closer main body 100, horizontal fixing member 200, and vertical fixing member 300 are flush with the door main body, which does not take up extra space, does not impair the aesthetic appearance of the door, and the door closer main body is not exposed and is less likely to be damaged, thereby ensuring the usability and extending the lifespan of the cam hydraulic door closer for narrow frame doors.

[0026] Second Embodiment 1, in the second embodiment of the present invention, the horizontal fixing member 200 is installed in the shape of a straight line and includes an integrally formed first door closer connection board 210 and a first door main body connection board 220. The first door closer connection board 210 is fixed to be flush with the top surface of the door closer main body 100 by a plurality of fixing screws. The first door main body connection board 220 is fixed to be flush with the horizontal edge of the door main body by a plurality of fixing screws.

[0027] Specifically, in this embodiment, the first door closer connection board 210 and the first door body connection board 220 are integrally formed, which can enhance the overall structural strength of the horizontal fixing member 200, ensure safety and reliability in subsequent use, and meet the need to firmly attach the door closer body 100 and the door body in a horizontally aligned manner.

[0028] Other parts of this embodiment are the same as those of the first embodiment, and the interpretation of the first embodiment is applied to features not described in this embodiment, and description thereof will be omitted here.

[0029] (Third embodiment) In the third embodiment of the present invention, as shown in Fig. 1, the vertical fixing member 300 is installed in an L-shape and includes an integrally formed second door closer connection board 310 and a second door main body connection board 320. The second door closer connection board 310 is installed horizontally and fixed by a plurality of fixing screws so as to be flush with the bottom surface of the door closer main body 100. The second door main body connection board 320 is installed vertically and is flush with the left end surface of the door closer main body 100. In addition, the second door main body connection board 320 is fixed by a plurality of fixing screws so as to be flush with the vertical side of the door main body.

[0030] Specifically, in this embodiment, the second door closer connection board 310 and the second door body connection board 320 are integrally formed, which can enhance the overall structural strength of the vertical fixing member 300, ensure safety and reliability in subsequent use, and meet the need to firmly attach the door closer body 100 and the door body in a horizontally aligned manner.

[0031] Other parts of this embodiment are the same as those of the first embodiment, and the interpretation of the first embodiment is applied to features not described in this embodiment, and description thereof will be omitted here.

[0032] (Fourth embodiment) In the fourth embodiment of the present invention, as shown in FIG. 1 , a door closer main body 100 includes a door closer housing 110, an automatic compensation valve assembly 120, a damping and compression assembly 130, and a drive spring member 140. A bore 111 filled with hydraulic oil is provided inside the door closer housing 110 along its axial direction. An eccentric camshaft 400 is rotatably supported within the door closer housing 110. The automatic compensation valve assembly 120 is slidably provided within the bore 111 and is located on the left side of the eccentric camshaft 400. The damping and compression assembly 130 is slidably provided within the bore 111 and is located on the right side of the eccentric camshaft 400. The drive spring member 140 is housed within the bore 111 and abuts against the damping and compression assembly 130 and the door closer housing 110, respectively. The drive spring member 140 biases the damping compression assembly 130 into flexible contact with the outer peripheral surface of the eccentric camshaft 400 .

[0033] Specifically, in this embodiment, when the door closer body 100 operates, the damping and compression assembly 130 always flexibly contacts the outer circumferential surface of the eccentric camshaft 400 via the drive spring member 140. When the eccentric camshaft 400 rotates, the damping and compression assembly 130 moves in tandem, compressing the drive spring member 140 and storing force in the drive spring member 140. At the same time, hydraulic oil flows through the automatic compensating valve assembly 120. Therefore, while the eccentric camshaft 400 is rotating, the damping and compression assembly 130 applies a damping effect to the eccentric camshaft 400, as well as a damping effect from the hydraulic oil. This reduces the speed at the moment the door is closed, providing sufficient cushioning.

[0034] Other parts of this embodiment are the same as those of the first embodiment, and the interpretation of the first embodiment is applied to features not described in this embodiment, and description thereof will be omitted here.

[0035] Fifth Embodiment 1 , the bore body 111 is partitioned into the automatic compensating valve assembly 120 and the damped compression assembly 130, and includes a first oil passage 150 located to the left of the automatic compensating valve assembly 120, a second oil passage 160 located to the right of the damped compression assembly 130, and a third oil passage 170 located between the automatic compensating valve assembly 120 and the damped compression assembly 130. The second oil passage 160 and the third oil passage 170 are in communication with each other. The automatic compensating valve assembly 120 is configured such that when the pressure in the first oil passage 150 exceeds a predetermined threshold, the automatic compensating valve assembly 120 allows hydraulic oil to flow between the first oil passage 150 and the third oil passage 170.

[0036] Specifically, in this embodiment, hydraulic oil is contained in all of the first oil passage 150, the second oil passage 160, and the third oil passage 170. When the door closer housing 110 rotates in conjunction with the rotation of the door body, the position of the damping / compression assembly 130 on the eccentric camshaft 400 changes. This changes the volume of the second oil passage 160, causing hydraulic oil to flow between the second oil passage 160 and the third oil passage 170. This generates a pressure difference between the first oil passage 150 and the third oil passage 170, changing the state of the automatic compensation valve assembly 120. Therefore, hydraulic oil flows between the first oil passage 150 and the third oil passage 170, maintaining a balance between the pressure difference between the first oil passage 150 and the third oil passage 170. In other words, the flow of hydraulic oil in the first oil passage 150, the second oil passage 160, and the third oil passage 170 can be synchronized with the movement of the door body.

[0037] Other parts of this embodiment are the same as those of the fourth embodiment, and the interpretation of the fourth embodiment is applied to features not described in this embodiment, and description thereof will be omitted here.

[0038] (Sixth embodiment) In a sixth embodiment of the present invention, as shown in FIG. 4 , an automatic compensating valve assembly 120 includes a valve piston 121, a valve body 122, a valve core member 123, and a core spring 124. The valve piston 121 is slidably disposed within the bore body 111. The valve body 122 is attached within the valve piston 121 and has a valve passage 1221 extending therethrough, the valve passage 1221 communicating with the first oil passage 150 and the third oil passage 170, respectively. The valve core member 123 is movably disposed within the valve passage 1221 and is used to open or close the valve passage 1221. The core spring 124 is housed within the valve passage 1221. One end of the core spring 124 is connected to the valve body 122. The other end of the core spring 124 is connected to the valve core member 123 and biases the valve core member 123 to close the valve passage 1221.

[0039] Specifically, in this embodiment, the movement of the valve core member 123 opens or closes the valve flow path 1221. The installation of the core spring 124 ensures the accuracy of the movement of the valve core member 123. When a pressure difference occurs between the first oil path 150 and the third oil path 170, the valve core member 123 is pushed by the hydraulic pressure, overcomes the elastic force of the core spring 124, and moves within the valve flow path 1221, thereby opening the valve flow path 1221. When the pressure difference between the first oil path 150 and the third oil path 170 is balanced, the valve core member 123 is pushed by the elastic force of the core spring 124, moves within the valve flow path 1221, and returns to its original position, blocking the valve flow path 1221. The state of the automatic compensating valve assembly 120 changes automatically, resulting in high reliability.

[0040] Other parts of this embodiment are the same as those of the fifth embodiment, and the interpretation of the fifth embodiment is applied to features not described in this embodiment, and description thereof will be omitted here.

[0041] Seventh Embodiment In the seventh embodiment of the present invention, as shown in Fig. 5, a damping compression assembly 130 includes a compression piston 131, a fixed pin 132, and a damping roller 133. The compression piston 131 is slidably disposed within the bore body 111. A drive spring member 140 abuts against the compression piston 131 and the door closer housing 110, respectively. A piston flow passage 1311 is formed through the compression piston 131, and the piston flow passage 1311 communicates with the second oil passage 160 and the third oil passage 170, respectively. The fixed pin 132 is fixed to an end of the compression piston 131 that is closer to the eccentric camshaft 400. The damping roller 133 is rotatably disposed on the fixed pin 132 and flexibly abuts against the outer circumferential surface of the eccentric camshaft 400.

[0042] Specifically, in this embodiment, the compression piston 131 and the inner wall of the bore 111 slide in step with each other, reducing the need for a guide structure for axially adjusting the compression piston 131. During use, the compression piston 131 is pushed by the drive spring member 140 to move. The compression piston 131 moves in the longitudinal direction of the door closer housing 110 due to the guide function of the bore 111. Therefore, the damping roller 133 accurately abuts against the eccentric camshaft 400, improving operational reliability.

[0043] Other parts of this embodiment are the same as those of the fifth embodiment, and the interpretation of the fifth embodiment is applied to features not described in this embodiment, and description thereof will be omitted here.

[0044] Eighth Embodiment 1, the drive spring member 140 includes an inner spring 141 and an outer spring 142. The outer spring 142 is placed over the outside of the inner spring 141. One ends of the outer spring 142 and the inner spring 141 simultaneously abut against the door closer housing 110, and the other ends of the outer spring 142 and the inner spring 141 simultaneously abut against the damping compression assembly 130.

[0045] Specifically, in this embodiment, the driving spring member 140 has a simple structure and a rational design. When the driving spring member 140 expands or contracts under force, the inner spring 141 and the outer spring 142 expand or contract accordingly and do not interfere with each other. Therefore, when the inner spring 141 and the outer spring 142 are used in combination, they are less likely to deform, which effectively extends the service life of the inner spring 141 and the outer spring 142. The combined design significantly improves the elasticity of the driving spring member 140 and ensures the verticality and stability of the spring force. Furthermore, it effectively prevents the inner spring 141 and the outer spring 142 from being damaged by excessive load.

[0046] Other parts of this embodiment are the same as those of the fourth embodiment, and the interpretation of the fourth embodiment is applied to features not described in this embodiment, and description thereof will be omitted here.

[0047] The above is merely a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. [Explanation of symbols]

[0048] 100 Door closer body 110 Door closer housing 111 Luminal body 120 Automatic Compensating Valve Assembly 121 Valve piston 122 Valve body 1221 Valve flow path 123 Valve core member 124 Core Spring 130 Damped Compression Assembly 131 Compression Piston 1311 Piston passage 132 fixing pin 133 Damping Roller 140 Drive spring member 141 Inner spring 142 Outer spring 150 First Oil Channel 160 Second Oil Route 170 Third Oil Route 200 Horizontal fixing member 210 First door closer connection board 220 First door main body connection board 300 Vertical fixing member 310 Second door closer connection board 320 Second door body connection board 400 eccentric camshaft

Claims

1. A cam hydraulic door closer for narrow frame doors used to connect a door body and a door frame, The door closer includes a door closer body, a horizontal fixing member, a vertical fixing member, and an eccentric camshaft. The door closer body is embedded in a corner of the door body and is flush with the door body, The horizontal fixing member has one end fixed to be flush with the upper surface of the door closer body, and the other end extending horizontally and fixed to be flush with the horizontal edge of the door body, The vertical fixing member has one end fixed to be flush with the bottom surface of the door closer body, and the other end extending vertically and being flush with the left end surface of the door closer body and also being flush with the vertical side of the door body, The eccentric camshaft has an axial direction perpendicular to the extension direction of the door closer body, one end of which is fixed and connected to the door frame, and the other end of which is rotatably connected to the inside of the door closer body. This is a cam hydraulic door closer for narrow frame doors.

2. 2. The cam hydraulic door closer for a narrow frame door according to claim 1, The horizontal fixing member is installed in the shape of a straight line and includes a first door closer connection board and a first door main body connection board which are integrally formed, the first door closer connection board is fixed to be flush with the upper surface of the door closer main body by a plurality of fixing screws, and the first door main body connection board is fixed to be flush with the horizontal edge of the door main body by a plurality of fixing screws. This is a cam hydraulic door closer for narrow frame doors.

3. 2. The cam hydraulic door closer for a narrow frame door according to claim 1, The vertical fixing member is installed in an L-shape and includes a second door closer connection board and a second door body connection board which are integrally formed; The second door closer connection board is installed horizontally and fixed flush with the bottom surface of the door closer body by a plurality of fixing screws; The second door body connection board is installed vertically, flush with the left end face of the door closer body, and fixed flush with the vertical side of the door body by a plurality of fixing screws. This is a cam hydraulic door closer for narrow frame doors.

4. 2. The cam hydraulic door closer for a narrow frame door according to claim 1, the door closer body includes a door closer housing, an automatic compensation valve assembly, a damping compression assembly, and a drive spring member; The door closer housing has an inner cavity for storing hydraulic oil along its axial direction, and the eccentric camshaft is rotatably supported within the door closer housing. the automatic compensating valve assembly is slidably mounted within the bore body and is located on a first side of the eccentric camshaft; the damping compression assembly is slidably mounted within the bore and is located on a second side of the eccentric camshaft opposite the first side; The drive spring member is housed in the inner cavity and abuts against the damping and compression assembly and the door closer housing, respectively, and biases the damping and compression assembly so that it flexibly abuts against the outer peripheral surface of the eccentric camshaft. This is a cam hydraulic door closer for narrow frame doors.

5. 5. The cam hydraulic door closer for a narrow frame door according to claim 4, the bore body is partitioned into the automatic compensating valve assembly and the damping compression assembly, and a first oil passage located on the left side of the automatic compensating valve assembly, a second oil passage located on the right side of the damping compression assembly, and a third oil passage located between the automatic compensating valve assembly and the damping compression assembly are formed, and the second oil passage and the third oil passage are in communication with each other; 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 cam hydraulic door closer for narrow frame doors.

6. 6. The cam hydraulic door closer for a narrow frame door according to claim 5, 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; the valve body is attached to 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 cam hydraulic door closer for narrow frame doors.

7. 6. The cam hydraulic door closer for a narrow frame door according to claim 5, the damping compression assembly includes a compression piston, a fixed pin, and a damping roller; the compression piston is slidably provided in the inner cavity body so that the drive spring member abuts against the compression piston and the door closer housing, respectively, and piston flow paths are provided therethrough that communicate with the second oil passage and the third oil passage, respectively; the fixed pin is fixed to an end of the compression piston that is closer to the eccentric camshaft, The damping roller is rotatably mounted on the fixed pin and flexibly contacts the outer circumferential surface of the eccentric camshaft. This is a cam hydraulic door closer for narrow frame doors.

8. 5. The cam hydraulic door closer for a narrow frame door according to claim 4, The drive spring member includes an inner spring and an outer spring, the outer spring is placed over the outer side 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 damping compression assembly. This is a cam hydraulic door closer for narrow frame doors.

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