Manufacturing method of integrated drive axle assembly

Abstract

This invention discloses a manufacturing method for an integrated drive axle assembly, comprising the following steps: S1, axle housing machining; S2, installation of a coolant delivery tank and a coolant spare tank; S3, machining and installation of a coolant jacket; S4, installation of the differential and half-shafts; S5, installation of the reducer; S6, installation of coolant delivery pipes; and S7, coolant delivery operation. This invention not only protects the oil seals but also cools the oil seals, input shaft sleeves, and axle housing, extending the service life of the oil seals and lubricating oil, thereby extending the service life of the drive axle.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an integrated drive axle assembly. Background Technology

[0002] The drive axle is located at the end of the vehicle's transmission system, and its technical condition directly affects the overall performance and reliability of the vehicle. The performance of the drive axle is closely related to its lubrication. Existing drive axles mainly use splash lubrication, which means that when the gears rotate, lubricating oil splashes and reaches the bearings and gear meshing points that need lubrication.

[0003] After a period of use, drive axles are prone to oil leaks. The main reason is that the rubber seals are exposed to alternating hot and cold temperatures for extended periods, causing them to lose a significant amount of plasticizers and softeners, leading to corrosion, aging, and hardening. Initially, this manifests as oil seepage, gradually progressing to dripping. Eventually, the seals may break, affecting the normal operation of the drive axle. Furthermore, the complex manufacturing process of existing drive axles increases production costs. Summary of the Invention

[0004] The purpose of this invention is to provide a technical solution for manufacturing an integrated drive axle assembly to address the shortcomings of existing technologies. This method not only protects the oil seals but also cools the oil seals, input shaft sleeves, and axle housing, extending the service life of the oil seals and lubricating oil, thereby extending the service life of the drive axle.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for manufacturing an integrated drive axle assembly, characterized by comprising the following steps:

[0007] S1, Bridge Housing Machining

[0008] a. First, select seamless steel pipes and saw them to form the required bridge shell shape;

[0009] b. Then, a cavity is opened downward along the center of the bridge housing. This cavity does not penetrate the bottom surface of the bridge housing. At the same time, shaft holes are opened from both ends of the bridge housing towards the center, so that the shaft holes are connected to the cavity. The cavity and shaft holes are then polished.

[0010] c. Next, install oil seal sleeves along both ends of the axle housing;

[0011] S2. Installation of coolant delivery tank and coolant spare tank

[0012] a. First, a suitable coolant delivery tank is manufactured according to the size of the bridge housing. A delivery pump, a first level sensor, and a second level sensor are installed inside the coolant delivery tank. A coolant output pipe is connected to the delivery pump and runs vertically upward through the coolant delivery tank. The first level sensor and the second level sensor are distributed up and down along the inner wall of the coolant delivery tank to detect the best and lowest coolant levels in the coolant delivery tank.

[0013] b. Then, symmetrical through slots are opened on both sides of the coolant delivery tank;

[0014] c. Next, machine a suitable coolant tank according to the size of the axle housing, and install a pump in the coolant tank;

[0015] d. Finally, fix the processed coolant delivery tank and coolant spare tank on both sides of the top surface of the axle housing;

[0016] S3, Coolant Jacket Machining and Installation

[0017] a. First, process a suitable jacket body according to the dimensions of the front and rear sides of the axle housing, so that the shape of the jacket body matches the corresponding side of the axle housing, and bend along the edge of the jacket body to form a folded edge, so that when the jacket body is connected to the axle housing, it can form a space for the flow of coolant.

[0018] b. Then, make through holes along the folded edges on both sides, and make return holes along the folded edge at the top.

[0019] c. Next, heat sinks of appropriate size are made according to the distance between the jacket body and the bridge housing and the distance between the upper and lower folded edges. Guide holes are opened on each heat sink. The processed heat sinks are installed at equal intervals on the inner side of the jacket body. Through the design of the above structure, it is easy to make a stable connection between the jacket body and the bridge housing. At the same time, the heat sinks can be brought close to the bridge housing to improve the heat dissipation efficiency of the bridge housing and extend the service life of the lubricating oil. The guide holes facilitate the flow of coolant.

[0020] d. Finally, the processed coolant jacket is fixedly installed on the front and rear sides of the axle housing and sealed. The coolant jacket is then fixedly installed to the axle housing using a reinforcement mechanism.

[0021] S4, differential and half-shaft mounting

[0022] Machine the appropriate differential and half shaft according to the dimensions of the cavity and shaft hole, connect the differential and half shaft and install them in the cavity and shaft hole respectively;

[0023] S5, Gearbox Installation

[0024] a. Select a suitable reducer according to the size of the cavity, and limit the reducer on the input shaft sleeve through the input shaft. Fix the entire input shaft sleeve on the top surface of the bridge housing.

[0025] b. After installation, connect the input shaft to the drive unit, inject lubricating oil into the axle housing, and install oil seals along the oil seal sleeves at both ends of the axle housing.

[0026] c. Next, install the first brake and the second brake along the outer end of the half shaft.

[0027] S6. Installation of coolant delivery pipe fittings

[0028] a. First, select a suitable length of distributor pipe according to the distance between the coolant delivery box and the first brake and input shaft sleeve. Connect one end of the distributor pipe to the input shaft sleeve and the other end to the oil seal sleeve located on the side of the first brake. At the same time, connect the coolant output pipe to the distributor pipe.

[0029] b. Then, select a guide tube of appropriate length according to the distance between the input shaft sleeve and the oil seal sleeve on the second brake side, and connect the guide tube to the input shaft sleeve and the oil seal sleeve on the second brake side.

[0030] c. Next, make a suitable return pipe according to the distance between the oil seal sleeves on both sides and the coolant jacket, connect the return pipe to the oil seal sleeve and the coolant jacket, and connect the coolant spare tank to the coolant delivery tank through the water supply pipe.

[0031] d. Finally, determine the size of the return plate according to the distance between the coolant delivery tank and the coolant jacket, process a suitable return plate, and install it on the coolant jacket and bridge housing so that the coolant jacket is connected to the coolant delivery tank through the return plate.

[0032] S7, Coolant delivery operation

[0033] a. First, fill the required amount of coolant into the coolant delivery tank and the coolant reserve tank respectively;

[0034] b. Then start the coolant delivery pump in the coolant delivery tank. The coolant in the coolant delivery tank is delivered to both sides through the coolant output pipe and the distributor pipe. The coolant in the oil seal sleeve near the first brake flows back to the coolant jackets on both sides through the return pipe. The coolant in the input shaft sleeve is delivered to the oil seal sleeve near the second brake through the guide pipe, and then flows back to the coolant jackets on both sides through the return pipe. The coolant in the coolant jacket can flow back to the coolant delivery tank through the return plate to realize the circulation of coolant. The coolant in the coolant spare tank can be delivered to the coolant delivery tank through the water supply pipe to ensure the circulation of coolant.

[0035] This manufacturing method is simple and can not only protect the oil seal, but also cool down the oil seal, input shaft sleeve and axle housing, extending the service life of the oil seal and lubricating oil, and thus extending the service life of the drive axle.

[0036] Furthermore, the size of the coolant delivery tank in step S2 is greater than or equal to the size of the coolant spare tank.

[0037] Furthermore, in step S2 process a, the height of the first liquid level sensor is higher than the height of the infusion pump.

[0038] Furthermore, the coolant reserve tank in step S2c is equipped with a level sensor to detect the level of the reserve coolant.

[0039] Furthermore, the reinforcement mechanism in step S3 process d includes a U-shaped frame, clamping blocks, and fastening rods. The clamping blocks are located at both ends of the U-shaped frame, and the two clamping blocks are connected by fastening rods. Through the design of the U-shaped frame, clamping blocks, and fastening rods, the stability and reliability of the coolant jacket installation can be improved.

[0040] Furthermore, in step S3, the distance between the jacket body and the side of the bridge housing is 3 to 10 cm.

[0041] Furthermore, in step S6, the return plate is provided with a slot, a return groove, and a mounting hole. The slot matches the coolant jacket, and the folded edge is provided with a return hole. The coolant delivery tank is provided with a through groove, and the return hole is connected to the through groove through the return groove. By passing screws through the mounting hole, the return plate is fixedly connected to the bridge housing. The return plate can not only fix the coolant jacket, but also facilitate the flow of coolant through the return groove, ensuring that the coolant can circulate.

[0042] The present invention, by adopting the above-described technical solution, has the following beneficial effects:

[0043] 1. The manufacturing method of the present invention has simple steps, which can not only protect the oil seal, but also cool down the oil seal, input shaft sleeve and axle housing, extend the service life of the oil seal and lubricating oil, and thus extend the service life of the drive axle.

[0044] 2. The above-mentioned structural design facilitates a stable connection between the jacket body and the bridge housing, while also allowing the heat sink to be placed close to the bridge housing, improving the heat dissipation efficiency of the bridge housing, extending the service life of the lubricating oil, and the guide holes facilitate the flow of coolant.

[0045] 3. The return plate not only fixes the coolant jacket, but also facilitates the flow of coolant through the return channel, ensuring that the coolant can circulate. Attached Figure Description

[0046] The present invention will be further described below with reference to the accompanying drawings:

[0047] Figure 1 This is a process flow diagram of the manufacturing method of the integrated drive axle assembly of the present invention;

[0048] Figure 2 This is a rendering of the drive bridge in this invention;

[0049] Figure 3 This is a schematic diagram of the coolant jacket structure in this invention;

[0050] Figure 4 This is a schematic diagram of the recirculation plate in this invention;

[0051] Figure 5 This is a schematic diagram of the coolant delivery tank in this invention;

[0052] Figure 6 This is a schematic diagram of the reinforcement mechanism in this invention.

[0053] In the diagram: 1-bridge housing; 2-first brake; 3-second brake; 4-input shaft sleeve; 5-coolant delivery tank; 6-coolant spare tank; 7-coolant jacket; 8-coolant output pipe; 9-distribution pipe; 10-guide pipe; 11-return pipe; 12-return plate; 13-reinforcing mechanism; 14-jacket body; 15-folded edge; 16-through hole; 17-return hole; 18-heat sink; 19-guide hole; 20-slot; 21-mounting hole; 22-return groove; 23-through groove; 24-first liquid level sensor; 25-second liquid level sensor; 26-infusion pump; 27-U-shaped frame; 28-clamping block; 29-fastening rod; 30-water supply pipe; 31-oil seal sleeve. Detailed Implementation

[0054] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0055] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0056] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0057] like Figures 1 to 6 The diagram shows a method for manufacturing the integrated drive axle assembly of the present invention, comprising the following steps:

[0058] S1, Bridge Housing 1 Machining

[0059] a. First, select a seamless steel pipe and saw it to form the required shape of bridge shell 1;

[0060] b. Then, a cavity is opened downward along the center of the bridge housing 1. This cavity does not penetrate the bottom surface of the bridge housing 1. At the same time, shaft holes are opened from both ends of the bridge housing 1 toward the center, so that the shaft holes are connected to the cavity. The cavity and shaft holes are then polished.

[0061] c. Next, install oil seal sleeves 31 along both ends of the bridge housing 1;

[0062] S2, coolant delivery tank 5 and coolant spare tank 6 installation

[0063] a. First, a suitable coolant delivery tank 5 is manufactured according to the dimensions of the bridge housing 1. A delivery pump 26, a first liquid level sensor 24, and a second liquid level sensor 25 are installed inside the coolant delivery tank 5. A coolant output pipe 8 is connected to the delivery pump 26. The coolant output pipe 8 runs vertically upward through the coolant delivery tank 5. The first liquid level sensor 24 and the second liquid level sensor 25 are distributed vertically along the inner wall of the coolant delivery tank 5 to detect the best and lowest liquid levels of the coolant in the coolant delivery tank 5. The height of the first liquid level sensor 24 is higher than the height of the delivery pump 26 to prevent the delivery pump 26 from running dry and being damaged.

[0064] b. Then, symmetrical through slots 23 are opened on both sides of the coolant delivery tank 5;

[0065] c. Next, a suitable coolant reserve tank 6 is manufactured according to the dimensions of the bridge housing 1, and a pump is installed inside the coolant reserve tank 6; the dimensions of the coolant delivery tank 5 are greater than or equal to the dimensions of the coolant reserve tank 6. A level sensor is installed inside the coolant reserve tank 6 to detect the level of the reserve coolant.

[0066] d. Finally, the processed coolant delivery tank 5 and coolant spare tank 6 are fixedly installed on both sides of the top surface of the bridge housing 1.

[0067] S3, Coolant Jacket 7 Machining and Installation

[0068] a. First, process a suitable jacket body 14 according to the dimensions of the front and rear sides of the bridge housing 1, so that the shape of the jacket body 14 matches the corresponding side of the bridge housing 1, and bend along the edge of the jacket body 14 to form a folded edge 15, which is used to form a space for the flow of coolant when the jacket body 14 is connected to the bridge housing 1.

[0069] b. Then, make through holes 16 along the folded edges 15 on both sides, and make return holes 17 along the folded edges 15 on the top.

[0070] c. Next, heat sinks 18 of appropriate size are made according to the distance between the jacket body 14 and the bridge housing 1 and the distance between the upper and lower folded edges 15, and guide holes 19 are opened on each heat sink 18. The processed heat sinks 18 are installed at equal intervals on the inner side of the jacket body 14. Through the design of the above structure, it is convenient to make a stable connection between the jacket body 14 and the bridge housing 1. At the same time, the heat sinks 18 can be brought close to the bridge housing 1 to improve the heat dissipation efficiency of the bridge housing 1 and extend the service life of the lubricating oil. The guide holes 19 facilitate the flow of coolant.

[0071] d. Finally, the processed coolant jacket 7 is fixedly installed on the front and rear sides of the axle housing 1 and sealed. The coolant jacket 7 is then fixedly installed to the axle housing 1 using the reinforcement mechanism 13. The reinforcement mechanism 13 includes a U-shaped frame 27, clamping blocks 28, and fastening rods 29. The clamping blocks 28 are located at both ends of the U-shaped frame 27, and the two clamping blocks 28 are connected by the fastening rods 29. The design of the U-shaped frame 27, clamping blocks 28, and fastening rods 29 can improve the stability and reliability of the coolant jacket 7 installation. The distance between the jacket body 14 and the side of the axle housing 1 is 3-10 cm.

[0072] S4, differential and half-shaft mounting

[0073] Machine the appropriate differential and half shaft according to the dimensions of the cavity and shaft hole, connect the differential and half shaft and install them in the cavity and shaft hole respectively;

[0074] S5, Gearbox Installation

[0075] a. Select a suitable reducer according to the size of the cavity, and limit the reducer on the input shaft sleeve 4 through the input shaft, and fix the entire input shaft sleeve 4 on the top surface of the bridge housing 1.

[0076] b. After installation, connect the input shaft to the drive unit, inject lubricating oil into the bridge housing 1, and install oil seals along the oil seal sleeves 31 at both ends of the bridge housing 1.

[0077] c. Next, install the first brake 2 and the second brake 3 along the outer end of the half shaft;

[0078] S6. Installation of coolant delivery pipe fittings

[0079] a. First, select a suitable length of distributor pipe 9 according to the distance between coolant delivery tank 5, first brake 2 and input shaft sleeve 4. Connect one end of distributor pipe 9 to input shaft sleeve 4 and the other end to oil seal sleeve 31 located on one side of first brake 2. At the same time, connect coolant output pipe 8 to distributor pipe 9.

[0080] b. Then, select a guide pipe 10 of appropriate length according to the distance between the input shaft sleeve 4 and the oil seal sleeve 31 on the side of the second brake 3, and connect the guide pipe 10 to the input shaft sleeve 4 and the oil seal sleeve 31 on the side of the second brake 3.

[0081] c. Next, make a suitable return pipe 11 according to the distance between the oil seal sleeves 31 on both sides and the coolant jacket 7, connect the return pipe 11 to the oil seal sleeves 31 and the coolant jacket 7, and connect the coolant spare tank 6 to the coolant delivery tank 5 through the water supply pipe 30.

[0082] d. Finally, determine the size of the return plate 12 according to the distance between the coolant delivery tank 5 and the coolant jacket 7, process a suitable return plate 12, and install it on the coolant jacket 7 and the bridge housing 1 so that the coolant jacket 7 is connected to the coolant delivery tank 5 through the return plate 12. The return plate 12 is provided with a slot 20, a return groove 22 and a mounting hole 21. The slot 20 matches the coolant jacket 7. The folded edge 15 is provided with a return hole 17. The coolant delivery tank 5 is provided with a through groove 23. The return hole 17 is connected to the through groove 23 through the return groove 22. By passing screws through the mounting hole 21, the return plate 12 and the bridge housing 1 are fixedly connected. The return plate 12 can not only fix the coolant jacket 7, but also facilitate the flow of coolant through the return groove 22, ensuring that the coolant can circulate.

[0083] S7, Coolant delivery operation

[0084] a. First, fill the required amount of coolant into the coolant delivery tank 5 and the coolant reserve tank 6 respectively;

[0085] b. Then start the pump 26 in the coolant delivery tank 5 to distribute the coolant in the coolant delivery tank 5 to both sides through the coolant output pipe 8 and the distributor pipe 9. The coolant in the oil seal sleeve 31 near the first brake 2 flows back to the coolant jackets 7 on both sides through the return pipe 11. The coolant in the input shaft sleeve 4 is delivered to the oil seal sleeve 31 near the second brake 3 through the guide pipe 10, and then flows back to the coolant jackets 7 on both sides through the return pipe 11. The coolant in the coolant jacket 7 can flow back to the coolant delivery tank 5 through the return plate 12 to realize the circulation of coolant. The coolant in the coolant spare tank 6 can be delivered to the coolant delivery tank 5 through the water supply pipe 30 to ensure the circulation of coolant.

[0086] The manufacturing method is simple and can not only protect the oil seal, but also cool down the oil seal, input shaft sleeve 4 and axle housing 1, extending the service life of the oil seal and lubricating oil, and thus extending the service life of the drive axle.

[0087] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to achieve substantially the same technical effect are all covered within the protection scope of the present invention.

Claims

1. A method for manufacturing an integrated drive axle assembly, characterized in that... Includes the following steps: S1, Bridge Housing Machining a. First, select seamless steel pipes and saw them to form the required bridge shell shape; b. Then, a cavity is opened downward along the center of the bridge housing. This cavity does not penetrate the bottom surface of the bridge housing. At the same time, shaft holes are opened from both ends of the bridge housing towards the center, so that the shaft holes are connected to the cavity. The cavity and shaft holes are then polished. c. Next, install oil seal sleeves along both ends of the axle housing; S2. Installation of coolant delivery tank and coolant spare tank a. First, a suitable coolant delivery tank is manufactured according to the size of the bridge housing. A delivery pump, a first level sensor, and a second level sensor are installed inside the coolant delivery tank. A coolant output pipe is connected to the delivery pump and runs vertically upward through the coolant delivery tank. The first level sensor and the second level sensor are distributed up and down along the inner wall of the coolant delivery tank to detect the best and lowest coolant levels in the coolant delivery tank. b. Then, symmetrical through slots are opened on both sides of the coolant delivery tank; c. Next, machine a suitable coolant tank according to the size of the axle housing, and install a pump in the coolant tank; d. Finally, fix the processed coolant delivery tank and coolant spare tank on both sides of the top surface of the axle housing; S3, Coolant Jacket Machining and Installation a. First, process a suitable jacket body according to the dimensions of the front and rear sides of the axle housing, so that the shape of the jacket body matches the corresponding side of the axle housing, and bend along the edge of the jacket body to form a folded edge, so that when the jacket body is connected to the axle housing, it can form a space for the flow of coolant. b. Then, make through holes along the folded edges on both sides, and make return holes along the folded edge at the top. c. Next, make heat sinks of appropriate size according to the distance between the jacket body and the bridge housing and the distance between the upper and lower folded edges, and open guide holes on each heat sink. Install the processed heat sinks at equal intervals on the inner side of the jacket body. d. Finally, the processed coolant jacket is fixedly installed on the front and rear sides of the axle housing and sealed. The coolant jacket is then fixedly installed to the axle housing using a reinforcement mechanism. S4, differential and half-shaft mounting Machine the appropriate differential and half shaft according to the dimensions of the cavity and shaft hole, connect the differential and half shaft and install them in the cavity and shaft hole respectively; S5, Gearbox Installation a. Select a suitable reducer according to the size of the cavity, and limit the reducer on the input shaft sleeve through the input shaft. Fix the entire input shaft sleeve on the top surface of the bridge housing. b. After installation, connect the input shaft to the drive unit, inject lubricating oil into the axle housing, and install oil seals along the oil seal sleeves at both ends of the axle housing. c. Next, install the first brake and the second brake along the outer end of the half shaft. S6. Installation of coolant delivery pipe fittings a. First, select a suitable length of distributor pipe according to the distance between the coolant delivery box and the first brake and input shaft sleeve. Connect one end of the distributor pipe to the input shaft sleeve and the other end to the oil seal sleeve located on the side of the first brake. At the same time, connect the coolant output pipe to the distributor pipe. b. Then, select a guide tube of appropriate length according to the distance between the input shaft sleeve and the oil seal sleeve on the second brake side, and connect the guide tube to the input shaft sleeve and the oil seal sleeve on the second brake side. c. Next, make a suitable return pipe according to the distance between the oil seal sleeves on both sides and the coolant jacket, connect the return pipe to the oil seal sleeve and the coolant jacket, and connect the coolant spare tank to the coolant delivery tank through the water supply pipe. d. Finally, determine the size of the return plate according to the distance between the coolant delivery tank and the coolant jacket, process a suitable return plate, and install it on the coolant jacket and bridge housing so that the coolant jacket is connected to the coolant delivery tank through the return plate. S7, Coolant delivery operation a. First, fill the required amount of coolant into the coolant delivery tank and the coolant reserve tank respectively; b. Then start the coolant delivery pump in the coolant delivery tank, and distribute the coolant in the coolant delivery tank to both sides through the coolant output pipe and the distributor pipe, near the oil seal sleeve of the first brake. The coolant flows back to the coolant jackets on both sides through the return pipe. The coolant in the input shaft sleeve is transported to the oil seal sleeve near the second brake through the guide pipe, and then flows back to the coolant jackets on both sides through the return pipe. The coolant in the coolant jacket can flow back to the coolant delivery tank through the return plate to realize the circulation of coolant. The coolant in the coolant spare tank can be transported to the coolant delivery tank through the water replenishment pipe to ensure the circulation of coolant.

2. The manufacturing method of the integrated drive axle assembly according to claim 1, characterized in that: The size of the coolant delivery tank in step S2 is greater than or equal to the size of the coolant spare tank.

3. The manufacturing method of the integrated drive axle assembly according to claim 1, characterized in that: In step S2 process a, the height of the first liquid level sensor is higher than the height of the infusion pump.

4. The manufacturing method of the integrated drive axle assembly according to claim 1, characterized in that: The coolant reserve tank in step S2c is equipped with a level sensor to detect the level of the reserve coolant.

5. The manufacturing method of the integrated drive axle assembly according to claim 1, characterized in that: The reinforcement mechanism in step S3 process d includes a U-shaped frame, clamping blocks and fastening rods. The clamping blocks are located at both ends of the U-shaped frame, and the two clamping blocks are connected by the fastening rods.

6. The manufacturing method of the integrated drive axle assembly according to claim 1, characterized in that: The distance between the jacket body and the side of the bridge housing in step S3 is 3 to 10 cm.

7. The manufacturing method of the integrated drive axle assembly according to claim 1, characterized in that: In step S6, process d, the return plate is provided with a slot, a return groove, and a mounting hole. The slot matches the coolant jacket. The folded edge is provided with a return hole. The coolant delivery tank is provided with a through groove. The return hole is connected to the through groove through the return groove. The return plate is fixedly connected to the bridge housing by passing a screw through the mounting hole.

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