Efficient heat dissipation structure of photovoltaic transformer

Abstract

The invention discloses an efficient heat dissipation structure of a photovoltaic transformer, and belongs to the technical field of heat dissipation of photovoltaic transformers. A photovoltaic transformer top body is fixedly mounted at the top of a photovoltaic transformer frame body, and one side of a photovoltaic transformer side body is in transmission connection with a winding and unwinding assembly through a ball screw nut pair; an electric capstan is fixedly installed on one side of the photovoltaic transformer top body, a cable is arranged in the take-up and pay-off assembly, and one end of the cable penetrates out of the take-up and pay-off assembly and extends to the outer side of the electric capstan, so that when the photovoltaic transformer dissipates heat, the cable can be released through the electric capstan or a driven capstan; the mooring rope is gradually separated from one side of the electric capstan and one side of the driving gear, and then the photovoltaic transformer side body is slowly opened in the mode that the photovoltaic transformer side body is hinged to the photovoltaic transformer frame body, so that the contact area between the containing cavity and the external environment can be increased. And rapid heat dissipation of the photovoltaic transformer is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of heat dissipation of photovoltaic transformers, and in particular relates to a high-efficiency heat dissipation structure of a photovoltaic transformer. Background Art

[0002] Photovoltaic transformers are transformers specifically used in photovoltaic (solar) power generation systems. Their main function is to convert the low-voltage AC power generated by the photovoltaic power generation system into a voltage level suitable for transmission to the power grid, or to adjust the voltage in some applications to adapt to load requirements. The design requirements for photovoltaic transformers are relatively special because the working environment and electrical characteristics of photovoltaic power generation systems are different from those of traditional power systems.

[0003] Photovoltaic power generation systems are mainly composed of photovoltaic modules, inverters, transformers and grid-connected equipment. Photovoltaic modules convert solar energy into direct current (DC), and then the inverter converts DC into alternating current (AC). However, the AC output by the inverter is usually low-voltage AC, which needs to be increased to a voltage level suitable for grid transmission (such as 380V, 10kV, 35kV, etc.) through a photovoltaic transformer.

[0004] The main functions of photovoltaic transformers are: Voltage conversion: Increase the low voltage AC power output by the inverter to a voltage level suitable for grid connection.

[0005] Isolation function: Provide electrical isolation to ensure the safety of electrical equipment and prevent direct electrical interference between devices.

[0006] Power regulation: Sometimes it is necessary to adjust the voltage and current according to actual needs to ensure the stability of the power grid.

[0007] Due to the sealed structure and high working power of photovoltaic transformers, photovoltaic transformers have an urgent need for heat dissipation. Compared with traditional oil-immersed transformers, photovoltaic transformers cannot be placed in oil for heat dissipation to ensure their own working efficiency, so their heat dissipation needs need to be met. Summary of the invention

[0008] In order to overcome the above defects, the present invention provides a photovoltaic transformer high-efficiency heat dissipation structure to solve the problems raised in the above background technology.

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a photovoltaic transformer high-efficiency heat dissipation structure, comprising a photovoltaic transformer frame, the side wall of the photovoltaic transformer frame is hinged with a photovoltaic transformer side body, the top of the photovoltaic transformer frame is fixedly installed with a photovoltaic transformer top body, one side of the photovoltaic transformer side body is connected to a retractable assembly through a ball screw nut pair, one side of the photovoltaic transformer top body is fixedly installed with an electric winch, a cable is arranged inside the retractable assembly, one end of the cable passes through the retractable assembly and extends to the outside of the electric winch.

[0010] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure, the retractable assembly includes an active member frame and a driven member frame, the active member frame is fixedly connected to the driven member frame, the active member frame is internally rotatably connected to a driving shaft, the outer periphery of the active shaft is sleeved with a driving gear, the driven member frame is internally rotatably connected to a driven gear, a driven winch is fixedly mounted on one side of the driven gear, the active gear is meshed with the driven gear, and one end of the cable is wound around the outer periphery of the driven winch.

[0011] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure also includes a guide assembly, the guide assembly includes a guide ring, a guide seat and a guide cylinder, the guide ring is fixedly connected to the photovoltaic transformer frame, one side of the guide seat is fixedly connected to the guide ring, the guide cylinder is rotatably connected to the guide seat, and the guide cylinder is movably connected to the cable.

[0012] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure, the ball screw nut pair includes a motor seat, a screw and a nut, the motor seat is fixedly connected to the side body of the photovoltaic transformer, both ends of the screw are rotatably connected to the motor seat, one side of the nut is fixedly connected to the active part frame, and the nut is sleeved on the outer periphery of the screw and movably connected to the screw.

[0013] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure also includes a ground contact component, the ground contact component includes a ground contact shaft and a ground contact seat, the ground contact shaft is fixedly connected to the active member frame, the ground contact seat is fixedly connected to the ground contact shaft, and the ground contact seat is protrudingly arranged at the outer edge of the active member frame.

[0014] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure, a photovoltaic transformer door body is hingedly connected to one side of the photovoltaic transformer frame, and a handle is fixedly installed on one side of the photovoltaic transformer door body.

[0015] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure, the photovoltaic transformer frame is a rectangular parallelepiped structure, three groups of photovoltaic transformer side bodies are arranged on the side of the photovoltaic transformer frame and are all hinged to the photovoltaic transformer frame, the photovoltaic transformer door body is arranged on the other side of the photovoltaic transformer frame and is hinged to the photovoltaic transformer door body, the photovoltaic transformer top body is arranged on the top surface of the photovoltaic transformer frame and is fixedly connected to the photovoltaic transformer frame, the photovoltaic transformer door body, the photovoltaic transformer top body and the photovoltaic transformer side body are surrounded by a accommodating cavity, and the accommodating cavity is arranged inside the photovoltaic transformer frame.

[0016] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure, the guide seat and the guide tube are distributed in a ring array inside the guide ring and form a cross-shaped structure.

[0017] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure, a servo motor can be fixedly installed on one side of the photovoltaic transformer side body, and the output end of the servo motor passes through the motor seat and is fixedly connected to the lead screw.

[0018] As a further solution of the present invention: a photovoltaic transformer high-efficiency heat dissipation structure, the ground contact seat is made of high-carbon steel, and its hardness reaches 60-75HRC.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. Since the side wall of the photovoltaic transformer frame is hinged with the photovoltaic transformer side body, the photovoltaic transformer top body is fixedly installed on the top of the photovoltaic transformer frame, one side of the photovoltaic transformer side body is connected with a retractable assembly through a ball screw nut pair, and one side of the photovoltaic transformer top body is fixedly installed with an electric winch, and a cable is arranged inside the retractable assembly, and one end of the cable passes through the retractable assembly and extends to the outside of the electric winch. Therefore, when the photovoltaic transformer dissipates heat, it can be released by the electric winch or the driven winch, so that the cable gradually disengages from one side of the electric winch on the one hand and from the one side of the driving gear on the other hand, and then the photovoltaic transformer side body is slowly opened by hingedly connecting the photovoltaic transformer side body to the photovoltaic transformer frame, so that the accommodating cavity can increase the contact area with the external environment, thereby realizing rapid heat dissipation of the photovoltaic transformer.

[0020] 2. By gradually tightening the electric winch or the driven winch, the side body of the photovoltaic transformer can be changed from an inclined state to a state of being placed in close contact with the photovoltaic transformer frame, and the equipment can be reset after heat dissipation.

[0021] 3. Since the guide assembly includes a guide ring, a guide seat and a guide cylinder, the guide ring is fixedly connected to the photovoltaic transformer frame, one side of the guide seat is fixedly connected to the guide ring, the guide cylinder is rotatably connected to the guide seat, and the guide cylinder is movably connected to the cable, the position of the cable can be limited by the guide cylinder, thereby avoiding the problem of cable wear caused by contact and friction between the cable and the accommodating cavity.

[0022] 4. Since the motor seat is fixedly connected to the side body of the photovoltaic transformer, both ends of the lead screw are rotatably connected to the motor seat, one side of the nut is fixedly connected to the active component frame, and the nut is sleeved on the outer periphery of the lead screw and movably connected to the lead screw. Therefore, the height of the retractable assembly can be adjusted by the ball screw nut pair to limit the unfolding angle of the photovoltaic transformer side body. Specifically, when the height of the retractable assembly is in the upper half position of the photovoltaic transformer side body, the cable can be released more and keep the photovoltaic transformer side body at a larger unfolding angle to facilitate heat dissipation. When the retractable assembly is in the lower half position of the photovoltaic transformer side body, the cable is released and restricted and keeps the photovoltaic transformer side body at a smaller unfolding angle, thereby controlling the heat dissipation speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of a photovoltaic transformer high-efficiency heat dissipation structure of the present invention.

[0024] Figure 2 It is a schematic structural diagram of a photovoltaic transformer in a photovoltaic transformer high-efficiency heat dissipation structure of the present invention after the side body is opened.

[0025] Figure 3 It is a structural schematic diagram of a retractable component in a photovoltaic transformer high-efficiency heat dissipation structure of the present invention.

[0026] Figure 4 The present invention is a schematic structural diagram of a guide component in a photovoltaic transformer high-efficiency heat dissipation structure.

[0027] Figure 5 The present invention is a schematic structural diagram of a ball screw nut pair in a photovoltaic transformer high-efficiency heat dissipation structure.

[0028] Figure 6 The present invention is a schematic diagram of the structure of a receiving cavity in a photovoltaic transformer high-efficiency heat dissipation structure.

[0029] In the figure: 1. photovoltaic transformer frame; 2. photovoltaic transformer door; 3. photovoltaic transformer top body; 4. photovoltaic transformer side body; 5. electric winch; 6. retractable assembly; 61. active component frame; 62. driven component frame; 63. driven gear; 64. driven winch; 65. winch pad; 66. active shaft; 67. active gear; 7. guide assembly; 71. guide ring; 72. guide seat; 73. guide cylinder; 8. cable; 9. ground contact assembly; 91. ground contact shaft; 92. ground contact seat; 10. ball screw nut pair; 101. motor seat; 102. screw; 103. nut; 11. accommodating cavity. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following is an explanation of an embodiment of the present invention based on the overall structure of the present invention.

[0032] As shown in the accompanying drawings, the present invention provides a technical solution: a photovoltaic transformer high-efficiency heat dissipation structure, comprising a photovoltaic transformer frame 1, a photovoltaic transformer side body 4 is hingedly connected to the side wall of the photovoltaic transformer frame 1, a photovoltaic transformer top body 3 is fixedly installed on the top of the photovoltaic transformer frame 1, a retractable assembly 6 is connected to one side of the photovoltaic transformer side body 4 through a ball screw nut pair 10, an electric winch 5 is fixedly installed on one side of the photovoltaic transformer top body 3, a cable 8 is arranged inside the retractable assembly 6, and one end of the cable 8 passes through the retractable assembly 6 and extends to the outside of the electric winch 5; Therefore, when the photovoltaic transformer is dissipating heat, it can be released through the electric winch 5 or the driven winch 64. The driven winch 64 can be driven by a servo motor fixedly installed on one side of the active component frame 61. The servo motor drives the active shaft 66 to rotate, the active shaft 66 then drives the active gear 67 to rotate, and the active gear 67 then drives the meshing driven gear 63 to rotate, thereby realizing the rotation of the driven winch 64, so that the cable 8 gradually disengages from one side of the electric winch 5 on the one hand, and gradually disengages from the one side of the active gear 67 on the other hand, and then the photovoltaic transformer side body 4 is slowly opened by hingedly connecting the photovoltaic transformer side body 4 with the photovoltaic transformer frame 1, so that the accommodating cavity 11 can increase the contact area with the external environment, thereby realizing rapid heat dissipation of the photovoltaic transformer.

[0033] At the same time, by gradually tightening the electric winch 5 or the driven winch 64, the photovoltaic transformer side body 4 can be changed from an inclined state to a state of being placed in close contact with the photovoltaic transformer frame 1, and the equipment can be reset after heat dissipation.

[0034] The retracting and unwinding assembly 6 includes an active member frame 61 and a driven member frame 62, wherein the active member frame 61 is fixedly connected to the driven member frame 62, the active member frame 61 is internally rotatably connected to a driving shaft 66, the outer periphery of the active shaft 66 is sleeved with a driving gear 67, the internal portion of the driven member frame 62 is rotatably connected to a driven gear 63, a driven winch 64 is fixedly mounted on one side of the driven gear 63, the active gear 67 is meshed with the driven gear 63, and one end of the cable 8 is wound around the outer periphery of the driven winch 64.

[0035] The heat dissipation mechanism further includes a guide assembly 7, which includes a guide ring 71, a guide seat 72 and a guide cylinder 73. The guide ring 71 is fixedly connected to the photovoltaic transformer frame 1, one side of the guide seat 72 is fixedly connected to the guide ring 71, the guide cylinder 73 is rotatably connected to the guide seat 72, and the guide cylinder 73 is movably connected to the cable 8. Therefore, the position of the cable 8 can be limited by the guide cylinder 73, thereby avoiding the problem of cable 8 being worn due to contact and friction between the cable 8 and the accommodating cavity 11.

[0036] The ball screw nut pair 10 includes a motor seat 101, a screw 102 and a nut 103. The motor seat 101 is fixedly connected to the photovoltaic transformer side body 4. Both ends of the screw 102 are rotatably connected to the motor seat 101. One side of the nut 103 is fixedly connected to the active component frame 61. The nut 103 is sleeved on the outer periphery of the screw 102 and is movably connected to the screw 102. Therefore, the height of the retractable assembly 6 can be adjusted by the ball screw nut pair 10 to limit the unfolding angle of the photovoltaic transformer side body 4. Specifically, when the height of the retractable assembly 6 is at the upper half position of the photovoltaic transformer side body 4, the cable 8 can be more released and keep the photovoltaic transformer side body 4 at a larger unfolding angle to facilitate heat dissipation. When the retractable assembly 6 is at the lower half position of the photovoltaic transformer side body 4, the cable 8 is released and limited and keeps the photovoltaic transformer side body 4 at a smaller unfolding angle, so as to control the heat dissipation speed.

[0037] The heat dissipation mechanism also includes a ground contact component 9, which can contact the ground before the retractable component 6 to avoid the problem of the retractable component 6 being damaged by contact with the ground. The ground contact component 9 includes a ground contact shaft 91 and a ground contact seat 92. The ground contact shaft 91 is fixedly connected to the active component frame 61, and the ground contact seat 92 is fixedly connected to the ground contact shaft 91. The ground contact seat 92 is protrudingly arranged at the outer edge of the active component frame 61.

[0038] A photovoltaic transformer door 2 is hinged on one side of the photovoltaic transformer frame 1 , and a handle is fixedly installed on one side of the photovoltaic transformer door 2 .

[0039] The photovoltaic transformer frame 1 is a rectangular parallelepiped structure, the three groups of photovoltaic transformer side bodies 4 are arranged on the sides of the photovoltaic transformer frame 1 and are all hinged to the photovoltaic transformer frame 1, the photovoltaic transformer door body 2 is arranged on the other side of the photovoltaic transformer frame 1 and is hinged to the photovoltaic transformer door body 2, the photovoltaic transformer top body 3 is arranged on the top surface of the photovoltaic transformer frame 1 and is fixedly connected to the photovoltaic transformer frame 1, the photovoltaic transformer door body 2, the photovoltaic transformer top body 3 and the photovoltaic transformer side bodies 4 are surrounded by a containing cavity 11, and the containing cavity 11 is arranged inside the photovoltaic transformer frame 1.

[0040] The guide seats 72 and guide tubes 73 are distributed in an annular array inside the guide ring 71 and form a cross-shaped structure.

[0041] A servo motor may be fixedly mounted on one side of the photovoltaic transformer side body 4 , and the output end of the servo motor passes through the motor seat 101 and is fixedly connected to the lead screw 102 , thereby driving the lead screw 102 to rotate and enabling the lead screw 102 to drive the retractable assembly 6 to move axially along the lead screw 102 .

[0042] The ground contact seat 92 is made of high carbon steel, and its hardness reaches 60-75HRC.

[0043] The working principle of the present invention is as follows: the cable 8 is gradually disengaged from one side of the electric winch 5 on the one hand, and is gradually disengaged from the one side of the driving gear 67 on the other hand, and then the photovoltaic transformer side body 4 is slowly opened by hingedly connecting the photovoltaic transformer side body 4 with the photovoltaic transformer frame 1, so that the accommodating cavity 11 can increase the contact area with the external environment, thereby realizing rapid heat dissipation of the photovoltaic transformer. At the same time, by gradually tightening the electric winch 5 or the driven winch 64, the photovoltaic transformer side body 4 can be changed from an inclined state to a state of being placed in close contact with the photovoltaic transformer frame 1, thereby realizing the reset of the equipment after heat dissipation.

[0044] Since the motor base 101 is fixedly connected to the photovoltaic transformer side body 4, both ends of the lead screw 102 are rotatably connected to the motor base 101, one side of the nut 103 is fixedly connected to the active component frame 61, and the nut 103 is sleeved on the outer periphery of the lead screw 102 and movably connected to the lead screw 102. Therefore, the height of the retractable assembly 6 can be adjusted by the ball screw nut pair 10 to limit the expansion angle of the photovoltaic transformer side body 4. Specifically, when the height of the retractable assembly 6 is in the upper half position of the photovoltaic transformer side body 4, the cable 8 can be released more and keep the photovoltaic transformer side body 4 at a larger expansion angle to facilitate heat dissipation. When the retractable assembly 6 is in the lower half position of the photovoltaic transformer side body 4, the cable 8 releases the restriction and keeps the photovoltaic transformer side body 4 at a smaller expansion angle, thereby controlling the heat dissipation speed.

[0045] What has been described above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical scheme and inventive concept of the present invention, which should be covered within the protection scope of the present invention. Various changes can also be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A photovoltaic transformer high-efficiency heat dissipation structure, characterized in that: The photovoltaic transformer frame (1) comprises a photovoltaic transformer side body (4) hingedly connected to the side wall of the photovoltaic transformer frame (1), a photovoltaic transformer top body (3) fixedly mounted on the top of the photovoltaic transformer frame (1), a retractable assembly (6) being transmission-connected to one side of the photovoltaic transformer side body (4) via a ball screw nut pair (10), an electric winch (5) being fixedly mounted on one side of the photovoltaic transformer top body (3), a cable (8) being arranged inside the retractable assembly (6), and one end of the cable (8) passing through the retractable assembly (6) and extending to the outside of the electric winch (5).

2. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 1, characterized in that: The retractable assembly (6) comprises a driving member frame (61) and a driven member frame (62), wherein the driving member frame (61) is fixedly connected to the driven member frame (62), a driving shaft (66) is rotatably connected inside the driving member frame (61), a driving gear (67) is sleeved on the outer circumference of the driving shaft (66), a driven gear (63) is rotatably connected inside the driven member frame (62), a driven winch (64) is fixedly mounted on one side of the driven gear (63), the driving gear (67) is meshed with the driven gear (63), and one end of the cable (8) is wound around the outer circumference of the driven winch (64).

3. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 2, characterized in that: It also comprises a guide assembly (7), the guide assembly (7) comprising a guide ring (71), a guide seat (72) and a guide cylinder (73), the guide ring (71) being fixedly connected to the photovoltaic transformer frame (1), one side of the guide seat (72) being fixedly connected to the guide ring (71), the guide cylinder (73) being rotatably connected to the guide seat (72), and the guide cylinder (73) being movably connected to the cable (8).

4. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 3, characterized in that: The ball screw nut pair (10) comprises a motor seat (101), a lead screw (102) and a nut (103); the motor seat (101) is fixedly connected to the photovoltaic transformer side body (4); both ends of the lead screw (102) are rotatably connected to the motor seat (101); one side of the nut (103) is fixedly connected to the active component frame (61); and the nut (103) is sleeved on the outer periphery of the lead screw (102) and movably connected to the lead screw (102).

5. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 4, characterized in that: The invention also comprises a ground contact assembly (9), wherein the ground contact assembly (9) comprises a ground contact shaft (91) and a ground contact seat (92), wherein the ground contact shaft (91) is fixedly connected to the active member frame (61), and the ground contact seat (92) is fixedly connected to the ground contact shaft (91), and the ground contact seat (92) is protrudingly arranged at the outer edge of the active member frame (61).

6. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 5, characterized in that: A photovoltaic transformer door body (2) is hingedly connected to one side of the photovoltaic transformer frame (1), and a handle is fixedly mounted on one side of the photovoltaic transformer door body (2).

7. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 6, characterized in that: The photovoltaic transformer frame (1) is a rectangular parallelepiped structure; the three sets of photovoltaic transformer side bodies (4) are arranged on the side of the photovoltaic transformer frame (1) and are all hinged to the photovoltaic transformer frame (1); the photovoltaic transformer door body (2) is arranged on the other side of the photovoltaic transformer frame (1) and is hinged to the photovoltaic transformer door body (2); the photovoltaic transformer top body (3) is arranged on the top surface of the photovoltaic transformer frame (1) and is fixedly connected to the photovoltaic transformer frame (1); the photovoltaic transformer door body (2), the photovoltaic transformer top body (3) and the photovoltaic transformer side bodies (4) are surrounded by a containing cavity (11); the containing cavity (11) is arranged inside the photovoltaic transformer frame (1).

8. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 7, characterized in that: The guide seats (72) and guide cylinders (73) are distributed in an annular array inside the guide ring (71) and form a cross-shaped structure.

9. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 8, characterized in that: A servo motor may be fixedly mounted on one side of the photovoltaic transformer side body (4), and the output end of the servo motor passes through the motor seat (101) and is fixedly connected to the lead screw (102).

10. A photovoltaic transformer high-efficiency heat dissipation structure according to claim 9, characterized in that: The ground contact seat (92) is made of high carbon steel, and its hardness reaches 60-75HRC.

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