Power tool

Abstract

The present application relates to a kind of electric tools, including shell assembly, drive mechanism installed in shell assembly, motion conversion mechanism and electric control assembly, reciprocating rod connected to motion conversion mechanism and fan fixed to drive mechanism, drive mechanism drives motion conversion mechanism, drives reciprocating rod to carry out reciprocating motion, drive mechanism drives fan synchronous rotation to generate cooling airflow;Shell assembly has first part and second part connected to the end of first part, first part contains motion conversion mechanism, reciprocating rod and at least part drive mechanism, second part contains electric control assembly and at least part drive mechanism, cooling air hole is formed on shell assembly, fan is double-sided fan, when fan rotates, drive mechanism, at least part first part and electric control assembly are all configured in the passage of cooling airflow.The present application is by being set first air inlet, second air inlet and air outlet on shell assembly, gear box shell periphery, electric control board and drive mechanism are effectively cooled.

Description

[Technical Field]

[0001] This invention relates to a power tool, and more particularly to a power tool used in decoration, construction and other similar applications. [Background Technology]

[0002] A reciprocating saw is a type of power tool used for cutting materials such as wood and metal. It is widely used in furniture and decoration industries. In actual operation, the motion conversion mechanism of the reciprocating saw converts the rotational motion of the drive mechanism into the reciprocating motion of the reciprocating rod, thereby driving the saw blade to perform high-frequency cutting operations.

[0003] To achieve maintenance-free and durable operation of reciprocating saws, brushless motors are typically used in the drive mechanism. However, brushless motors require circuit components such as switching and rectifier elements, which generate heat as they supply power to the motor. Therefore, when using brushless motors, it is necessary to effectively cool these heat-generating circuit components.

[0004] In addition, the motion conversion mechanism of a reciprocating saw generates significant heat and reaches high temperatures during operation. To protect the operator, a rubber sleeve is usually wrapped around the motion conversion mechanism for heat insulation. However, this also affects the heat dissipation of this part, leading to excessive internal temperature rise, which in turn affects the lubrication effect of the internal grease and shortens the overall lifespan of the machine.

[0005] An improvement to the above structure can be found in Chinese Invention Patent No. CN111526970B, published on June 9, 2023, which discloses a saw comprising a housing with an intake port and an exhaust port, a brushless motor supported on the housing, a power supply circuit for supplying power to at least one circuit element to the brushless motor, and a fan driven by the rotation of the brushless motor to generate cooling air flowing from the intake port to the exhaust port within the housing, wherein at least one circuit element is cooled by the cooling air generated by the fan. However, this airflow path cannot cool the heat at the motion conversion mechanism, and cannot completely avoid the short lifespan of the entire machine due to heat generation.

[0006] Therefore, it is indeed necessary to provide an improved power tool to overcome the shortcomings of the existing technology. [Summary of the Invention]

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a power tool with good heat dissipation.

[0008] The present invention solves the problems of the prior art by adopting the following technical solution: A power tool includes a housing assembly, a drive mechanism, a motion conversion mechanism, and an electronic control component mounted on the housing assembly, a reciprocating rod connected to the motion conversion mechanism, and a fan fixed to the drive mechanism. The electronic control component is electrically connected to the drive mechanism to control the operating state of the drive mechanism. The drive mechanism drives the motion conversion mechanism, causing the reciprocating rod to reciprocate. The drive mechanism drives the fan to rotate synchronously to generate a cooling airflow. The housing assembly has a first part and a second part connected to the end of the first part. The first part houses the motion conversion mechanism, the reciprocating rod, and at least a portion of the drive mechanism. The second part houses the electronic control component and at least a portion of the drive mechanism. Cooling vents are formed on the housing assembly. The fan is a double-sided fan. When the fan rotates, the drive mechanism, at least a portion of the first part, and the electronic control component are all arranged in the cooling airflow path.

[0009] A further improvement is as follows: the cooling vent has a first air inlet and at least one air outlet. The first air inlet is opened in the first part and is located on the side of the first part opposite to the reciprocating rod. The air outlet is located radially outward of the fan. The cooling airflow includes a first cooling airflow that enters the housing assembly from the first air inlet and then flows out of the housing assembly from the air outlet. The first cooling airflow dissipates heat from the first part.

[0010] A further improvement is as follows: the cooling air vent also has a second air inlet, which is opened in the second part and located on the side of the second part away from the drive mechanism. The cooling airflow also includes a second cooling airflow that enters the housing assembly from the second air inlet and then flows out of the housing assembly from the air outlet. The second cooling airflow flows sequentially through the electronic control component and the drive mechanism.

[0011] A further improvement is as follows: the first part has a gearbox housing for mounting the motion conversion mechanism and a rubber sleeve fitted around the outer periphery of the gearbox housing. Several air ducts are formed between the gearbox housing and the rubber sleeve. The air ducts extend along the axial direction of the reciprocating rod and are connected to the first cooling airflow generated by the rotation of the fan.

[0012] A further improvement is that a number of ribs are provided between the rubber sleeve and the gearbox housing, and the ribs extend along the axial direction of the reciprocating rod.

[0013] A further improvement is that the rib is located on the inner circumference of the rubber sleeve, and the rib contacts the outer surface of the gearbox housing to form the air duct.

[0014] A further improvement is as follows: the rib is provided on the outer surface of the gearbox housing, and the rib contacts the inner surface of the rubber sleeve to form the air duct.

[0015] A further improvement is as follows: the second part has a motor part for mounting the drive mechanism, a gripping part, a battery mounting part, and a connecting part connected to the motor part and the battery mounting part. The connecting part is located below the motor part, and the electronic control component is mounted on the connecting part.

[0016] A further improvement is that the second air inlet is opened in the connecting part, located on the side of the connecting part opposite to the gripping part.

[0017] A further improvement is that the electronic control assembly has an electronic control board connected to the drive assembly, and the extension direction of the electronic control board intersects the axial direction of the reciprocating rod.

[0018] The present invention can also solve the problems of the prior art by adopting the following technical solution: A power tool includes a housing assembly, a drive mechanism, a motion conversion mechanism and an electronic control assembly mounted on the housing assembly, a reciprocating rod connected to the motion conversion mechanism and a fan fixed to the drive mechanism. The electronic control assembly is electrically connected to the drive mechanism to control the operating state of the drive mechanism. The drive mechanism drives the motion conversion mechanism to drive the reciprocating rod to perform reciprocating motion. The drive mechanism drives the fan to rotate synchronously to generate cooling airflow. The housing assembly has a first air inlet, a second air inlet and an air outlet. The first air inlet and the air outlet form a first cooling airflow, which dissipates heat from part of the housing assembly. The second air inlet and the air outlet form a second cooling airflow, which flows sequentially through the electronic control assembly and the drive mechanism. The first air inlet and the second air inlet are located on both sides of the air outlet.

[0019] A further improvement is as follows: the housing assembly has a gearbox housing for mounting the motion conversion mechanism and a rubber sleeve fitted around the outer periphery of the gearbox housing. Several air ducts are formed between the gearbox housing and the rubber sleeve. The air ducts extend along the axial direction of the reciprocating rod and are connected to the first cooling airflow generated by the rotation of the fan, so as to dissipate heat from the outer surface of the gearbox housing.

[0020] Compared with the prior art, the present invention has the following beneficial effects: by opening a first air inlet, a second air inlet, and an air outlet on the housing assembly, a dual cooling airflow is formed, which effectively dissipates heat from the outer periphery of the gearbox housing, the electronic control board, and the drive mechanism; in addition, the first air inlet is opened on the rubber sleeve, so the cooling airflow only flows through the outer periphery of the gearbox housing, carrying away heat while preventing debris from entering the interior of the gearbox housing. [Attached Image Description]

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings:

[0022] Figure 1 This is a schematic diagram of the overall structure of a power tool according to a preferred embodiment of the present invention;

[0023] Figure 2 yes Figure 1 A cross-sectional view of the power tool shown;

[0024] Figure 3 yes Figure 1 The diagram shows the structure of a power tool for removing a rubber sleeve.

[0025] Figure 4 yes Figure 1 The diagram shows the structure of the rubber sleeve in the power tool.

[0026] Figure 5 yes Figure 1 The power tool shown is a cross-sectional view along the AA direction;

[0027] Figure 6 yes Figure 4 A schematic diagram of the fan structure in the power tool shown;

[0028] Figure 7 yes Figure 1 Disassembly diagram of the main parts of the power tool shown;

[0029] Figure 8 yes Figure 2 A magnified view of a portion of the power tool shown;

[0030] Figure 9 yes Figure 7 The diagram shows the structural schematic of the main parts in the power tool.

[0031] Figure 10 yes Figure 1 The power tool shown is a cross-sectional view along the BB direction.

Detailed Implementation Methods

[0032] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0033] The terminology used in this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," "rear," "left," and "right" that indicate orientation or positional relationship are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0034] Please see Figure 1 and Figure 2 As shown, the embodiments of the present invention relate to a power tool, and a reciprocating saw 100 is a preferred embodiment of this embodiment. The reciprocating saw 100 is widely used in decoration, construction and other fields. The reciprocating saw 100 includes a housing assembly 1, a drive mechanism 2 and a reciprocating rod 4 installed in the housing assembly 1, a motion conversion mechanism 3 connecting the drive mechanism 2 and the reciprocating rod 4, a fan 5 fixed to the drive mechanism 2, a clamping mechanism 7 installed at the front end of the reciprocating rod 4, a support shoe 8 for adjusting the extension length of the saw blade, an electronic control assembly 9 for controlling the operating state of the drive assembly 2, and a power source for providing electrical energy. The clamping mechanism 6 fixes the saw blade to the reciprocating rod 4. The drive mechanism 2 is started under the action of the power source, driving the motion conversion mechanism 3 and causing the reciprocating rod 4 and the saw blade to reciprocate, so that the reciprocating saw 100 performs high-frequency cutting operations on the workpiece; at the same time, the drive mechanism 2 drives the fan 5 to rotate synchronously to generate cooling airflow to dissipate heat from the reciprocating saw 100.

[0035] In this embodiment, the drive mechanism 2, motion conversion mechanism 3, reciprocating rod 4, and electronic control assembly 9 are all arranged within the housing assembly 1. The housing assembly 1 includes a first part 11 and a second part 12 connected to the end of the first part 11. The first part 11 is mainly used to house the motion conversion mechanism 3, the reciprocating rod 4, and at least part of the drive mechanism 2. The second part 12 is made of plastic and is used to house the electronic control assembly 9 and at least part of the drive mechanism 2. The first part 11 and the second part 12 are fastened together with screws to assemble them into a single unit.

[0036] The housing assembly 1 has cooling vents, and when the fan 5 rotates, the drive mechanism 2, at least part of the first part 11, and the electronic control assembly 9 are arranged in the cooling airflow path.

[0037] Furthermore, the aforementioned housing assembly 1 is provided with a first air inlet 13, a second air inlet 14, and an air outlet 15, with the first air inlet 13 and the second air inlet 14 located on opposite sides of the air outlet 15. The first air inlet 13 and the air outlet 15 form a first cooling airflow B to dissipate heat from the first part 11 of the housing assembly 1; the second air inlet 14 and the air outlet 15 form a second cooling airflow A, which flows sequentially through the electronic control assembly 9 and the drive mechanism 2.

[0038] In this embodiment, the cooling vents consist of a first air inlet 13, a second air inlet 14, and an air outlet 15. The first air inlet 13 is located in the first part 11 on the side opposite to the reciprocating rod 4. The second air outlet 14 is located in the second part 12 on the side away from the drive mechanism 2. The air outlet 15 is located radially outward of the fan 5. The first air inlet 13, the second air inlet 14, and the air outlet 15 form a dual cooling airflow. Specifically, the dual cooling airflows include a first cooling airflow B that enters the housing assembly 1 from the first air inlet 13 and then exits the housing assembly 1 from the air outlet 15, and a second cooling airflow A that enters the second part 12 from the second air inlet 14 and then exits the second part 12 from the air outlet 15.

[0039] Combination Figure 6 As shown, fan 5 is a centrifugal double-sided fan, which has a first fan blade 51 and a second fan blade 52 disposed opposite to the first fan blade 51.

[0040] Please refer to the following: Figures 1 to 4 As shown, the first part 11 has a gearbox housing 111 for mounting the motion conversion mechanism 3 and a rubber sleeve 112 fitted around the outer periphery of the gearbox housing 111. The rubber sleeve 112 is shaped to fit the gearbox housing 111. Several air ducts are formed between the gearbox housing 111 and the rubber sleeve 112. The air ducts extend along the axial direction of the reciprocating rod 4 and are connected to the first cooling airflow B generated by the rotation of the first blade 51 of the fan 5.

[0041] The gearbox housing 111 is made of metal. The first cooling airflow B flows through the outer periphery of the gearbox housing 111 and can carry away the heat generated by the motion conversion mechanism 3 and other components inside the gearbox housing 111, resulting in good heat dissipation. At the same time, the first cooling airflow B only flows on the outer surface of the gearbox housing 111, preventing the debris generated during the reciprocating saw 100 from entering the machine.

[0042] Among them, the rubber sleeve 112 is made of rubber and is used for heat insulation.

[0043] In this embodiment, a plurality of ribs 113 are provided between the rubber sleeve 112 and the gearbox housing 111, and the ribs 113 extend along the axial direction of the reciprocating rod 4.

[0044] Specifically, the rib 113 is provided on the inner circumference of the rubber sleeve 112, and the rib 113 contacts the outer surface of the gearbox housing 111 to form an air duct.

[0045] Specifically, the rib 113 can also be provided on the outer surface of the gearbox housing 111, and the rib 113 contacts the inner surface of the rubber sleeve 112 to form an air duct.

[0046] In this embodiment, the second part 12 has a motor part 121 for mounting a drive mechanism, a grip part 122, a battery mounting part 123, and a connecting part 124 connected to the battery mounting part 123. The grip part 122, the battery mounting part 123, and the connecting part 124 are generally C-shaped.

[0047] The connecting portion 124 is located below the motor portion 121, and the electronic control component 9 is housed within the connecting portion 124. A second air inlet 14 is formed in the connecting portion 124 and located on the side of the connecting portion 124 opposite to the grip portion 122. Cooling airflow enters the connecting portion 124 through the second air inlet 14, first flowing through the electronic control component 9 and then through the drive mechanism 2, thereby effectively dissipating heat from the circuit components within the electronic control component 9.

[0048] Combination Figure 7 and Figure 8 As shown, the drive mechanism 2 has a motor housing 24 mounted within the motor section 121, a motor 21 housed within the motor housing 24, a motor shaft 22 protruding into the gearbox housing 111, and a tapered portion 23 formed at the front end of the motor shaft 22. The tapered portion 23 engages with the motion conversion mechanism 3. The motor housing 24 covers the motor 21, and its modular design facilitates installation. Furthermore, the motor housing 24 and the motor section 121 form a double-layer housing, providing insulation protection on one hand and reducing vibration transmission on the other.

[0049] The aforementioned motion conversion mechanism 3 includes an intermediate shaft 31 housed within a gearbox housing 111, a large bevel gear 32 sleeved around the outer periphery of the intermediate shaft 31, a crank disc 34, an eccentric pin 33 connecting the large bevel gear 32 and the crank disc 34, a crank pin 35 connecting the crank disc 34 and the reciprocating rod 4, and a counterweight 36. The intermediate shaft 31 is rotatably mounted to the gearbox housing 111 via bearings, and is arranged approximately perpendicular to the motor shaft 22. The lower end of the large bevel gear 32 forms a bevel tooth 321, and the motor shaft 22 is located at the lower end of the large bevel gear 32, and the two are meshed together, thereby transmitting the rotation of the drive mechanism 2 to the motion conversion mechanism 3. The large bevel gear 32 has a locating pin 322 protruding upward from its end face, and the locating pin 322 is located on the central axis of the intermediate shaft 31. The eccentric pin 33 is interference-fitted into the large bevel gear 32, and the eccentric pin 33 is offset from the central axis of the intermediate shaft 31. The crank disc 34 is connected to the large bevel gear 32 via a locating pin 322 and an eccentric pin 33, and the crank disc 34 rotates eccentrically around the motor shaft 22.

[0050] The crank disc 34 has an eccentric portion 341 protruding downward from its lower end and a crank portion 342 protruding upward from its upper end. The eccentric portion 341 and the crank portion 342 are located on both sides of the end face of the crank disc 34 and are distributed on both sides of the plane containing the central axis of the intermediate shaft 31. A counterweight 36 is fitted around the outer periphery of the eccentric portion 341, driving the counterweight 36 to reciprocate approximately along the axial direction of the motor shaft 22. A crank pin 35 is mounted on the crank portion 342 and connected to the reciprocating rod 4, driving the reciprocating rod 4 to reciprocate approximately along the axial direction of the motor shaft 22. Preferably, a needle roller bearing and a bushing are fitted around the outer periphery of the crank pin 35. The crank pin 35 and the eccentric portion 341 drive the reciprocating rod 4 and the counterweight 36 to move in opposite directions, reducing vibration.

[0051] Combination Figure 9 As shown, the reciprocating rod 4 has a cylindrical sliding part 41 and a yoke 42 fixed to the end of the sliding part 41. The yoke 42 has an annular hole 421, and the crank pin 35 is installed in the annular hole, thereby converting the rotation into linear reciprocating motion.

[0052] Combination Figure 10 As shown, the reciprocating saw 100 also includes a lifting mechanism 6 that drives the reciprocating rod 4 to swing, which is used to drive the reciprocating rod 4 to swing along the axial direction of the intermediate shaft 31.

[0053] The aforementioned lifting mechanism 6 includes a lifting wheel 61 and a lifting pin 62 connected to the lifting wheel 61. The lifting pin 62 can adjust whether the lifting wheel 61 abuts against or disengages from the large gear 32. The upper end face of the large gear 32 is cam-shaped. When the lifting wheel 61 abuts against the large gear 32, the rotation of the large gear 32 can drive the lifting wheel 61 to move up and down along the axis of the intermediate shaft 31, thereby driving the guide rail 51 to rotate around the rotating part 511.

[0054] Please refer to the following: Figure 1 and Figure 2 As shown, the electronic control assembly 9 includes an electronic control board 91 electrically connected to the drive mechanism 2 and the power source, a switch 92 controlling the operation of the drive mechanism 2, and a trigger 93 connected to the switch 92. Specifically, the electronic control board 91 is located within the connecting portion 124. The switch 92 and the trigger 93 are installed within the grip portion 122. When the operator grips the grip portion 122, they can pull the trigger 93 to trigger the switch 92, thereby activating the drive mechanism 2.

[0055] The electronic control board 91 is equipped with multiple switching elements, rectifier elements and other circuit elements. The second cooling airflow A directly dissipates heat from the circuit elements to avoid damage caused by overheating.

[0056] The present invention forms a dual cooling airflow by opening a first air inlet 13, a second air inlet 14 and an air outlet 15 on the housing assembly 1, which effectively dissipates heat from the outer periphery of the gearbox housing 111, the electronic control board 91 and the drive mechanism 2; in addition, the first air inlet 13 is opened on the rubber sleeve 112, and the cooling airflow only flows through the outer periphery of the gearbox housing 111, which carries away heat and prevents debris from entering the interior of the gearbox housing 111.

[0057] This invention is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many other alternatives to the power tools of this invention can be developed without departing from the principles and scope of the invention. The scope of protection of this invention is defined by the claims.

Claims

1. A power tool, comprising a housing assembly, a drive mechanism, a motion conversion mechanism, and an electronic control assembly mounted on the housing assembly, a reciprocating rod connected to the motion conversion mechanism, and a fan fixed to the drive mechanism, wherein the electronic control assembly is electrically connected to the drive mechanism to control the operating state of the drive mechanism, the drive mechanism drives the motion conversion mechanism to reciprocate the reciprocating rod, and the drive mechanism drives the fan to rotate synchronously to generate cooling airflow; characterized in that: The housing assembly has a first portion and a second portion connected to the end of the first portion. The first portion houses the motion conversion mechanism, the reciprocating rod, and at least a portion of the drive mechanism. The second portion houses the electronic control component and at least a portion of the drive mechanism. Cooling vents are formed on the housing assembly. The fan is a double-sided fan with a first blade and a second blade opposite to the first blade. A first cooling airflow generated by the rotation of the first blade and a second cooling airflow generated by the rotation of the second blade form a dual cooling airflow. The outlet of the dual cooling airflow is located radially outward of the double-sided fan. When the double-sided fan rotates, the drive mechanism, at least a portion of the first portion, and the electronic control component are all arranged in the path of the dual cooling airflow. The first cooling airflow flows on the outer surface of the gearbox housing of the first portion, and the second cooling airflow flows sequentially through the electronic control component and the drive mechanism.

2. The power tool according to claim 1, characterized in that: The cooling vent has a first air inlet and at least one air outlet. The first air inlet is opened in the first part and is located on the side of the first part opposite to the reciprocating rod. The cooling airflow includes a first cooling airflow that enters the housing assembly from the first air inlet and then flows out of the housing assembly from the air outlet. The first cooling airflow dissipates heat from the first part.

3. The power tool according to claim 2, characterized in that: The cooling vent also has a second air inlet, which is opened in the second part and located on the side of the second part away from the drive mechanism. The cooling airflow also includes a second cooling airflow that enters the housing assembly from the second air inlet and then flows out of the housing assembly from the air outlet. The second cooling airflow sequentially cools the electronic control component and the drive mechanism.

4. The power tool according to claim 2, characterized in that: The first part has a gearbox housing for mounting the motion conversion mechanism and a rubber sleeve fitted around the outer periphery of the gearbox housing. Several air ducts are formed between the gearbox housing and the rubber sleeve. The air ducts extend along the axial direction of the reciprocating rod and are connected to the first cooling airflow generated by the rotation of the fan.

5. The power tool according to claim 4, characterized in that: Several ribs are provided between the rubber sleeve and the gearbox housing, and the ribs extend along the axial direction of the reciprocating rod.

6. The power tool according to claim 5, characterized in that: The rib is located on the inner circumference of the rubber sleeve, and the rib contacts the outer surface of the gearbox housing to form the air duct.

7. The power tool according to claim 5, characterized in that: The rib is provided on the outer surface of the gearbox housing, and the rib contacts the inner surface of the rubber sleeve to form the air duct.

8. The power tool according to claim 3, characterized in that: The second part has a motor part for mounting the drive mechanism, a gripping part, a battery mounting part, and a connecting part connected to the motor part and the battery mounting part. The connecting part is located below the motor part, and the electronic control component is mounted on the connecting part.

9. The power tool according to claim 8, characterized in that: The second air inlet is formed in the connecting part and is located on the side of the connecting part away from the gripping part.

10. The power tool according to claim 8, characterized in that: The electronic control assembly has an electronic control board connected to the drive assembly, the extension direction of which intersects the axial direction of the reciprocating rod.

11. A power tool, comprising a housing assembly, a drive mechanism, a motion conversion mechanism, and an electronic control assembly mounted on the housing assembly, a reciprocating rod connected to the motion conversion mechanism, and a fan fixed to the drive mechanism, wherein the electronic control assembly is electrically connected to the drive mechanism to control the operating state of the drive mechanism, the drive mechanism drives the motion conversion mechanism to reciprocate the reciprocating rod, and the drive mechanism drives the fan to rotate synchronously to generate cooling airflow; characterized in that: The housing assembly has a first air inlet, a second air inlet, and an air outlet. The first air inlet and the air outlet form a first cooling airflow, which dissipates heat from a portion of the housing assembly. The second air inlet and the air outlet form a second cooling airflow, which flows sequentially through the electronic control component and the drive mechanism. The housing assembly has a motor section for mounting the drive mechanism and a connecting section located below the motor section. The electronic control component is disposed in the connecting section, and the second cooling airflow enters the connecting section directly from the second air inlet. The first air inlet and the second air inlet are located on opposite sides of the air outlet.

12. The power tool according to claim 11, characterized in that: The housing assembly has a gearbox housing for mounting the motion conversion mechanism and a rubber sleeve fitted around the outer periphery of the gearbox housing. Several air ducts are formed between the gearbox housing and the rubber sleeve. The air ducts extend along the axial direction of the reciprocating rod and are connected to the first cooling airflow generated by the rotation of the fan, so as to dissipate heat from the outer surface of the gearbox housing.

Images