Blade slitting punch press

Abstract

The invention relates to the technical field of punching machines, and provides a blade slitting punching machine which comprises a supporting base. The eccentric driving wheel is arranged on a power output device on the supporting seat; one end of the pull rod is connected with the eccentric driving wheel; the vertical guide mechanism is arranged on the supporting seat; the connecting piece is slidably mounted on the vertical guide mechanism, and the other end of the pull rod is connected with the connecting piece; the fixed die is installed on the lower portion of the supporting base, and a female die head with a through hole is arranged on the fixed die in a protruding mode; the movable die is installed on the connecting piece, and a male die head matched with the female die head is arranged on the movable die in a protruding mode; a cavity is formed in the male die head, and a fluid channel opening is formed in the side wall of the movable die and communicated with the cavity in the male die head. The internal cavity is formed in the male die head of the movable die, the fluid channel openings communicated with the cavity are formed in the two sides of the movable die, and when the movable die conducts high-speed reciprocating stamping, heat generated by friction of the male die head can be taken away by cooling fluid entering the cavity, so that the movable die is kept in a stable temperature interval all the time.

Description

Technical Field

[0001] This invention relates to the field of punch press technology, and more specifically, to a blade slitting punch press. Background Technology

[0002] Commonly used blades include razor blades, eyebrow trimmer blades, and razor blades. Depending on the intended use, different materials can be selected for the blades. After annealing and surface treatment, the blank is cut out using the appropriate forming process. There are two main types of blade forming processes: stamping and machining (including wire cutting, milling / turning, and laser cutting). Stamping is widely used due to its high forming speed. The raw material is placed between stamping dies, and the blade blank is quickly formed as the dies reciprocate at high speed.

[0003] Currently, high-speed stamping forming of blades can reach a stamping speed of several hundred times per minute. However, in actual use, as the stamping speed increases, the vibration, friction, and heat generated by the high-speed movement between the dies will intensify. This will eventually cause thermal shrinkage of the metal fixed and moving dies. This will result in a large error gap between the moving and fixed dies after mold closing, leading to a decrease in positioning accuracy and ultimately, defects in the final product. Summary of the Invention

[0004] The present invention aims to solve the technical problems existing in the prior art. To this end, the present invention provides a blade slitting punch.

[0005] To achieve the above objectives, the present invention provides a blade slitting punch press, comprising: a support base with a power output device; an eccentric drive wheel disposed on the power output device on the support base; a pull rod, one end of which is connected to the eccentric drive wheel; a vertical guide mechanism disposed on the support base; a connecting member slidably mounted on the vertical guide mechanism, the other end of the pull rod being connected to the connecting member; a fixed die mounted on the lower part of the support base, the fixed die having a protruding die head with a through hole; a moving die mounted on the connecting member, the moving die having a protruding punch head that matches the die head; positioning pins mounted around the fixed die, the moving die having holes allowing the positioning pins to pass through; the punch head having a cavity, and the side wall of the moving die having a fluid channel opening communicating with the cavity inside the punch head, so as to allow cooling fluid to enter the cavity from the fluid channel opening and then flow out from the other side.

[0006] As a further improvement to the solution, the vertical guide mechanism includes: a reinforcing plate, symmetrically fixed on the support base; a slide rail, mounted on the reinforcing plate; a middle plate, on both sides of which ball bearing sliders are mounted and slidably mounted on the slide rail via the ball bearing sliders; one end of the pull rod is connected to the middle plate, and the connecting piece is connected to the middle plate.

[0007] As a further improvement to the solution, the punch head includes: a first mold body detachably mounted on the moving mold; a mold cover plate mounted on the first mold body; and a die head assembly mounted in the first mold body. The mold cover plate has a first die head opening that allows the die head assembly to pass through. A gap is left between the die head assembly and the mold cover plate. The first mold body has first connecting ports on both sides for fluid to enter and exit. After the first mold body is mounted on the moving mold, the fluid channel port communicates with the first connecting port. Cooling fluid enters the first mold body and flows through the gap between the die head assemblies.

[0008] As a further improvement to the solution, it also includes: the mold head assembly has guide ramps on both sides that extend at an angle to the position of the first connection port.

[0009] As a further improvement to the solution, it also includes: a blocking part, located in the middle part of the mold head assembly, for guiding the cooling fluid to flow to both sides.

[0010] As a further improvement to the solution, it also includes: a semiconductor cooling chip and a fan installed sequentially in one of the fluid channel ports; and a filter installed at the fluid channel ports on both sides.

[0011] As a further improvement to the solution, it also includes: a washer ring, which is sleeved on the positioning post and is flush with the die head; and a constraint ring, which is screwed onto the positioning post and maintains a gap with the washer ring, the gap being used to constrain the steel strip.

[0012] As a further improvement to the solution, the die head includes: a second mold body detachably mounted on the moving mold, the second mold body having a recessed mounting groove, the mounting groove having a second die head opening matching the die head assembly, and the moving mold having a discharge port allowing waste material to fall into a region matching the position of the second die head opening; a second connecting port, formed on the side wall of the moving mold and extending inward through the bottom of the mounting groove, the fixed mold having a fluid channel port matching and communicating with the second connecting port; an isolation cover, installed in the mounting groove, the isolation cover having a third die head opening identical to the second die head opening; a support strip, arranged around the edge of the third die head opening, a gap being left between the isolation cover and the bottom of the mounting groove, thereby forming a sealed cavity, the two second connecting ports leading to this cavity.

[0013] As a further improvement to the solution, it also includes: a constraint component, disposed between the mold cover plate and the mold head assembly, for filling the gap between the mold head assembly and the first mold body, thereby forming a narrow gap between the mold head assembly and the first mold body; and a connecting piece, disposed in the gap between the isolation cover and the mounting groove, to occupy the gap of the isolation cover, thereby providing more contact surface between the isolation cover and the mounting groove.

[0014] As a further improvement to the solution, the support bars on the isolation cover are provided with an integrally connected barrier, so that the cooling fluid entering the cavity between the isolation cover and the mounting groove can flow around the area covered by the support bars in a fixed path.

[0015] The present invention brings the following effects: 1. This invention provides an internal cavity in the punch head of the moving die and fluid channels connecting the cavity on both sides of the moving die. When the moving die performs high-speed reciprocating stamping, the heat generated by friction in the punch head is carried away by the cooling fluid entering the cavity, so that the moving die is kept in a stable temperature range. This effectively avoids the problem of inaccurate stamping accuracy caused by metal shrinkage due to overheating of the punch head. This further improves the stamping speed and ensures that the stamped products do not lose precision.

[0016] 2. The internal cavity on the fixed mold, after the addition of cooling fluid, can also prevent the die head from shrinking due to overheating, which would lead to inaccurate stamping accuracy. Combined with the heat dissipation effect of the moving mold head, it can achieve a more stable stamping effect and further improve the stamping speed.

[0017] 3. With the pad ring and constraint ring working together, the steel strip can achieve stable transmission and movement between the moving die and the fixed die, avoiding steel strip deviation during the stamping process. Attached Figure Description

[0018] Figure 1 This is a complete schematic diagram of the present invention.

[0019] Figure 2 This is a schematic diagram of the vertical guide mechanism of the present invention.

[0020] Figure 3 This is a schematic diagram of the moving mold and the fixed mold of the present invention.

[0021] Figure 4 For the present invention Figure 3 A schematic diagram with the steel strip removed.

[0022] Figure 5 This is a schematic diagram of the moving model of the present invention.

[0023] Figure 6This is a schematic diagram of the punch head of the present invention.

[0024] Figure 7 This is a schematic diagram of the head assembly and constraint components of the present invention.

[0025] Figure 8 This is a schematic diagram showing the flow path of the fluid through the die assembly according to the present invention.

[0026] Figure 9 This is a schematic diagram of the semiconductor cooling chip, fan, and filter of the present invention.

[0027] Figure 10 This is a schematic diagram of the gasket and constraint ring of the present invention.

[0028] Figure 11 This is a schematic diagram of the second module of the present invention after the isolation cover has been removed.

[0029] Figure 12 This is a schematic diagram of the isolation cover of the present invention.

[0030] Figure 13 This is a schematic diagram showing the flow path of the fluid within the isolation cover according to the present invention.

[0031] The correspondence between the reference numerals and the names of the components in the attached drawings is as follows: 11-Support base, 12-Eccentric drive wheel, 13-Tie rod, 14-Vertical guide mechanism, 15-Connector, 16-Fixed mold, 161-Die head, 17-Moving mold, 171-Fluid channel port, 172-Punch head, 18-Positioning pin, 21-Reinforcing plate, 22-Slide rail, 23-Intermediate plate, 24-Ball slider, 31-First mold body, 32-Mold cover plate, 33-Mold head assembly, 34-First mold head opening, 35-First 41-Connecting port, 42-Guiding ramp, 43-Blocking part, 51-Semiconductor cooling chip, 52-Fan, 53-Filter screen, 61-Waist ring, 62-Blocking ring, 162-Discharge port, 71-Second mold body, 72-Insertion groove, 73-Second mold head opening, 74-Second connecting port, 75-Isolation cover, 76-Third mold head opening, 77-Supporting strip, 81-Connecting piece, 91-Blocking part, 300-Steel strip. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] This invention specifically discloses a blade slitting punch press, such as... Figures 1-13As shown, the device includes: a support base 11 with a power output device, on which a power output device driven by a servo motor is mounted. An eccentric drive wheel 12 is mounted on the power output device, and one end of a pull rod 13 is rotatably connected to the eccentric drive wheel 12. A vertical guide mechanism 14 is mounted in the middle of the support base 11, and a connecting member 15 is slidably mounted on the vertical guide mechanism 14. The other end of the pull rod 13 is connected to the connecting member 15. Therefore, as the eccentric drive wheel 12 rotates, the pull rod 13 pulls the connecting member 15 to reciprocate vertically on the vertical guide mechanism 14. A fixed die 16 is fixedly installed on the lower part of the support base 11. The fixed die 16 has a protruding die head 161 with a through hole. The moving die 17 is installed on the connecting member 15. The moving die 17 can reciprocate in the up and down direction with the connecting member 15. The moving die 17 has a protruding punch head 172 that matches the die head 161. The raw material steel strip 300 for the blade is placed between the moving die 17 and the fixed die 16. While the steel strip 300 is being pulled, the moving die 17 punches downward to cut the steel strip 300. Positioning posts 18 are fixedly installed around the fixed die 16, and the moving die 17 has allowable positioning posts. The moving die 17 slides on the positioning post 18 through the hole 18 to prevent it from shifting. To address the issue of thermal shrinkage of the metal punch 172 caused by frictional overheating during high-speed punching of the steel strip 300, which could affect punching accuracy, a cavity is provided inside the punch 172. A fluid channel port 171 is opened on the side wall of the moving die 17, communicating with the cavity inside the punch 172. During operation, the moving die 17 requires the fluid channel port 171 to inject cooling fluid into the cavity. The cooling fluid can be either coolant or cold air. Cooling fluid enters the cavity from one side of the fluid channel 171 and flows out from the other side of the fluid channel 171, and this process continues. During this process, the heated punch 172 can be cooled down, so that even when the punch 172 is performing high-speed punching, it can be kept at a fixed temperature by the cooling fluid in the cavity inside the punch 172. This avoids thermal shrinkage of the metal punch 172, which would affect the punching accuracy. Once the thermal shrinkage problem of the punch 172 is solved, the punching speed of the moving die 17 can be further increased.

[0035] Reference Figure 2 As shown, the vertical guide mechanism 14 includes: a reinforcing plate 21 symmetrically fixed on the support base 11; a slide rail 22 fixedly mounted on the reinforcing plate 21; ball bearing sliders 24 mounted on both sides of the intermediate plate 23; the intermediate plate 23 slidably mounted on the slide rail 22 via the ball bearing sliders 24; one end of the pull rod 13 connected to the intermediate plate 23; and a connecting piece 15 connected to the intermediate plate 23. Thanks to the cooperation of the ball bearing sliders 24 and the slide rail 22, when the pull rod 13 pulls the connecting piece 15 to move up and down reciprocally, the ball bearing sliders 24 generate low noise and are less prone to vibration.

[0036] Reference Figures 3-8 As shown, the punch head 172 can be further improved, including: a first mold body 31 detachably mounted on the moving mold 17, a mold cover plate 32 mounted on the first mold body 31, and a die head assembly 33 mounted inside the first mold body 31. The die head assembly 33 is milled from a single piece of metal, and the die head shape required for punching and cutting off the steel strip 300 is milled according to the shape required by the cutting tool. These different shaped dies are on the same metal block. A first die head opening 34 is opened on the mold cover plate 32 to allow the die head assembly 33 to pass through. Each die head protrudes from its corresponding first die head opening 34. The protruding part is the die head portion for punching the steel strip 300. After the die cover plate 32 is closed, a gap remains between the die cover plate 32 and the die head assembly 33. This gap is the space through which cooling fluid can pass. The first die body 31 has first connecting ports 35 on both sides for fluid to enter and exit. After the first die body 31 is installed on the moving die 17, the fluid channel port 171 communicates with the first connecting ports 35. In use, cold air or coolant can be connected to the fluid channel port 171. (Refer to...) Figure 8 As shown, after these fluids enter the first mold body 31, they flow through the gaps between the mold head assembly 33 and flow out from the fluid channel port 171 on the other side. During this process, the cooling fluid can cool down each mold head of the mold head assembly 33.

[0037] Reference Figure 7 As shown, it also includes: guide ramps 41 on both sides of the mold head assembly 33, extending at an angle to the position of the first connecting port 35. After the cooling fluid enters the first mold body 31 from the first connecting port 35, it can be guided by the guide ramps 41 to enter the gaps of each mold head more smoothly. When cold air is injected, the guide ramps 41 have a more obvious guiding effect.

[0038] Reference Figure 7 and Figure 8 As shown, it also includes a blocking portion 43 located in the middle of the mold head assembly 33 to guide the cooling fluid to flow to both sides. The blocking portion 43 prevents all the fluid from flowing out through the middle gap of the mold head assembly 33, thus preventing the surrounding areas of the mold head from being effectively cooled.

[0039] Reference Figure 9As shown, when the moving mold 17 is cooled by cold air, it can be set up as follows, mainly including: a semiconductor cooling chip 51 and a fan 52 installed sequentially in one of the fluid channel ports 171. The semiconductor cooling chip 51 and the fan 52 work together. The airflow blown out is cooled down after passing through the semiconductor cooling chip 51. After entering the first mold body 31, it can carry away the heat generated by the friction of the mold head, thereby achieving the purpose of cooling. The filter screen 53 is installed at the fluid channel ports 171 on both sides to filter dust particles.

[0040] It should be noted that when using coolant for cooling, a pipe can be directly connected to the fluid channel port 171, and coolant can be injected into the cavity inside the first mold body 31 through the pipe, so that the mold head of the mold head assembly 33 is immersed in coolant, thereby maintaining the temperature of the mold head assembly 33.

[0041] Reference Figure 3 and Figure 10 As shown, it also includes: a washer 61 sleeved on the positioning post 18, the washer 61 being flush with the die head 161; and a constraint ring 62 screwed onto the positioning post 18, with a certain gap between the constraint ring 62 and the washer 61, which is used to constrain the steel strip 300. In use, the steel strip 300 passes through the gap between the washer 61 and the constraint ring 62, so that the steel strip 300 will not shift its position when the moving die 17 performs high-speed punching.

[0042] Reference Figures 10-13As shown, as a further improvement, cooling measures have been added to the die head 161 on the fixed die 16, mainly including: a second die body 71 detachably mounted on the moving die 17, the second die body 71 having a recessed mounting groove 72, a second die head opening 73 matching the die head assembly 33 within the mounting groove 72, and a discharge port 162 on the moving die 17 in an area matching the position of the second die head opening 73, allowing scrap material to fall. The scrap material from the steel strip 300 being punched falls downwards through the second die head opening 73. The material is discharged from the discharge port 162. Two second connecting ports 74 are opened on the side wall of the moving mold 17. The second connecting ports 74 extend inward and exit from the bottom of the mounting groove 72. The fixed mold 16 has a fluid channel port 171 that matches and communicates with the second connecting ports 74. Cooling fluid enters the second connecting port from one of the fluid channel ports 171, then flows out from the bottom of the mounting groove 72, and exits from the other second connecting port 74 and the fluid channel port 171. An isolation device is detachably installed inside the mounting groove 72. The isolation cover 75 has a third die opening 76, identical to the second die opening 73. The isolation cover 75 is the part that ultimately contacts the steel strip 300, meaning the steel strip 300 rests on it. Supporting strips 77 are arranged around the edge of the third die opening 76 on the side of the isolation cover 75 facing the mounting groove 72. The function of the supporting strips 77 is to effectively support the edge of the third die opening 76 during the downward punching of the steel strip 300 by the die assembly 33, preventing deformation of the third die opening 76 of the isolation cover 75 during the punching process. A gap is left between the isolation cover 75 and the bottom of the mounting groove 72, forming a sealed cavity. Two second connecting ports 74 lead to this cavity, allowing cooling fluid entering through the second connecting ports 74 to flow within the cavity and exit through the other second connecting port 74. This process cools the third die opening 76 portion of the isolation cover 75, preventing overheating and thermal shrinkage due to friction. Combined with the heat dissipation effect of the moving die 17, a more stable stamping effect can be achieved, and the stamping speed can be further improved.

[0043] Reference Figure 12 and Figure 13As shown, the support bars 77 on the isolation cover 75 are connected by an integral barrier 91, so that the cooling fluid entering the cavity between the isolation cover 75 and the mounting groove 72 flows along a fixed path and around the area covered by the support bars 77. Since the third mold head opening 76 is set according to the shape of the mold head assembly 33, the notches are separated from each other. Therefore, the cavity formed between the isolation cover 75 and the mounting groove 72 is divided into multiple areas by the support bars 77. In order to allow the cooling fluid entering the cavity to flow to every corner, the support bars 77 that are close to each other at the two second connecting ports 74 are connected together by the barrier 91, thereby preventing the fluid from directly flowing to the other second connecting port 74, so that the fluid entering the cavity can flow to every corner of the cavity.

[0044] Reference Figure 7 and Figure 11 As shown, it also includes: a constraint component 42, which is disposed between the mold cover plate 32 and the mold head assembly 33. Since the mold head assembly 33 is distributed in different positions, there are large gaps between some places and the side wall of the first mold body 31. Therefore, by filling and reducing these large gaps through the constraint component 42, a narrow gap can be formed between the mold head assembly 33 and the first mold body 31. After the fluid enters the first mold body 31, the flow rate will be faster. The same situation as the mold head assembly 33 exists on the isolation cover 75. Therefore, a connecting piece 81 is filled in the gap between the isolation cover 75 and the mounting groove 72 to occupy a large area of ​​the isolation cover 75. In addition to increasing the fluid flow rate, the connecting piece 81 can also make the isolation cover 75 and the mounting groove 72 have more contact surface. In this way, during the process of the moving mold 17 reciprocatingly pressing down on the isolation cover 75, the large area of ​​the isolation cover 75 will not sink downward. By filling this part of the gap with the connecting piece 81, the isolation cover 75 can be kept from deformation.

[0045] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications, improvements, and substitutions without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A blade slitting punch press, comprising: A support base (11) with a power output device; an eccentric drive wheel (12) mounted on the power output device on the support base (11); a pull rod (13) with one end connected to the eccentric drive wheel (12); characterized in that it further includes: a vertical guide mechanism (14) mounted on the support base (11); a connecting member (15) slidably mounted on the vertical guide mechanism (14), with the other end of the pull rod (13) connected to the connecting member (15); a fixed mold (16) mounted on the lower part of the support base (11), the fixed mold (16) having a protruding die head with a through hole. (161); Moving mold (17), mounted on the connecting member (15), the moving mold (17) has a protruding punch (172) that matches the die head (161); positioning pin (18), mounted around the fixed mold (16), the moving mold (17) has a hole that allows the positioning pin (18) to pass through; the punch (172) has a cavity, the side wall of the moving mold (17) has a fluid channel port (171) that communicates with the cavity in the punch (172) so that cooling fluid can enter the cavity from the fluid channel port (171) and then flow out from the other side.

2. The blade slitting punch press according to claim 1, characterized in that, The vertical guide mechanism (14) includes: a reinforcing plate (21) symmetrically fixed on the support base (11); a slide rail (22) mounted on the reinforcing plate (21); an intermediate plate (23) with ball bearing sliders (24) mounted on both sides and slidably mounted on the slide rail (22) via the ball bearing sliders (24); one end of the pull rod (13) is connected to the intermediate plate (23), and the connector (15) is connected to the intermediate plate (23).

3. The blade slitting punch press according to claim 2, characterized in that, The punch head (172) includes: a first mold body (31) detachably mounted on the moving mold (17); a mold cover plate (32) mounted on the first mold body (31); a mold head assembly (33) mounted inside the first mold body (31), the mold cover plate (32) having a first mold head opening (34) allowing the mold head assembly (33) to pass through, a gap being left between the mold head assembly (33) and the mold cover plate (32), and first connecting ports (35) for fluid to enter and exit being opened on both sides of the first mold body (31). After the first mold body (31) is mounted on the moving mold (17), the fluid channel opening (171) is connected to the first connecting port (35), and the cooling fluid enters the first mold body (31) and flows through the gap between the mold head assembly (33).

4. The blade slitting punch press according to claim 3, characterized in that, Also includes: The mold head assembly (33) has guide ramps (41) on both sides that extend at the position of the first connecting port (35).

5. The blade slitting punch press according to claim 4, characterized in that, Also includes: The blocking part (43) is located in the middle part of the mold head assembly (33) to guide the cooling fluid to flow to both sides.

6. The blade slitting punch press according to any one of claims 1-5, characterized in that, Also includes: A semiconductor cooling chip (51) and a fan (52) are sequentially installed in one of the fluid channel ports (171); a filter (53) is installed at the fluid channel ports (171) on both sides.

7. The blade slitting punch press according to any one of claims 5, characterized in that, Also includes: A washer (61) is fitted onto the positioning post (18) and is flush with the die head (161); A constraint ring (62) is screwed onto the positioning post (18) and maintains a gap with the pad ring (61) to constrain the steel strip (300).

8. The blade slitting punch press according to claim 7, characterized in that, The die head (161) includes: a second mold body (71) detachably mounted on the moving mold (17), the second mold body (71) having a recessed mounting groove (72), the mounting groove (72) having a second die head opening (73) matching the die head assembly (33), and the moving mold (17) having a discharge port (162) allowing waste material to fall into the area matching the position of the second die head opening (73); and a second connecting port (74) opened on the side wall of the moving mold (17) and extending inward through the bottom of the mounting groove (72). The fixed mold (16) is provided with a fluid channel port (171) that matches and communicates with the second communication port (74); an isolation cover (75) is installed in the mounting groove (72), and the isolation cover (75) has a third mold head port (76) that is the same as the second mold head port (73); a support strip (77) is arranged around the edge of the third mold head port (76), and a gap is left between the isolation cover (75) and the bottom of the mounting groove (72) to form a sealed cavity, and the two second communication ports (74) lead to the cavity.

9. The blade slitting punch press according to claim 8, characterized in that, Also includes: A constraint component (42) is disposed between the mold cover plate (32) and the mold head assembly (33) to fill the gap between the mold head assembly (33) and the first mold body (31), thereby forming a narrow gap between the mold head assembly (33) and the first mold body (31); a connecting piece (81) is disposed in the gap between the isolation cover (75) and the mounting groove (72) to occupy the gap of the isolation cover (75) and to provide more contact surface between the isolation cover (75) and the mounting groove (72).

10. The blade slitting punch press according to claim 9, characterized in that, An integral barrier (91) is provided between the support bars (77) on the isolation cover (75) so that the cooling fluid entering the cavity between the isolation cover (75) and the mounting groove (72) flows around the area covered by the support bar (77) in a fixed line.

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