Patent Application
20200139505
The present application claims the priority of Chinese patent application No. 201811313316.0, filed on Nov. 6, 2018, which is hereby incorporated by reference in its entirety.
The present disclosure relates to a cleaning device, and more particularly to a wheel weight-reducing pit cleaning device.
As the weight of the wheels directly affects the fuel economy of the vehicle, the vehicle industry continues to pursue lightweight, especially in the wheel industry. For the wheel formed by casting process, the weight-reducing pits are often arranged on the wheel flange. With the processing of the wheel flange, the edge of the weight-reducing pit will generate a lot of burrs. If the burrs are not removed in time, the wheel will cause corrosion failure in the use process. Therefore, an automatic cleaning device is needed to remove the burrs on the edge of the weight-reducing pit on the wheel flange.
It is an object of the present disclosure to provide a weight-reducing pit cleaning device which, in use, is capable of cleaning and removing the burrs on the edges of the drain groove and the weight loss groove at the wheel weight-reducing pit.
In order to achieve the above object, the technical solution of the present disclosure is as follows: weight-reducing pit cleaning device, is comprised a frame 1, lower guiding posts I 2, a lower cylinder I 3, lower guiding sleeves I 4, a lower fixing plate I 5, a rotary joint 6, a spline shaft 7, a pulley I 8, a lower servo motor I 9, a pulley II 10, a synchronous belt I 11, a pulley III 12, a lower lifting plate I 13, a support frame 14, a spline sleeve 15, a hollow shaft 16, a bearing pedestal I 17, a ball bowl 18, a guard plate 19, a center brush 20, a lower servo motor II 21, a lower lifting plate II 22, a lower guiding rail I 23, a lower gear I 24, a lower rack I 25, a left vertical plate 26, a lower servo motor III 27, a lower gear II 28, a lower rack II 29, a lower guiding rail II 30, a sliding plate I 31, a side brush 32, a shaft I 33, a spring I 34, a shaft II 35, a bearing pedestal II 36, a lower servo motor IV 37, a lower overturning plate 38, a lower servo motor V 39, a shaft III 40, a bearing pedestal III 41, lower guiding posts II 42, lower guiding sleeves II 43, a lower fixing plate II 44, a lower lifting plate III 45, a lower gear III 46, a lower rack III 47, a lower guiding rail III 48, a sliding plate II 49, a lower servo motor VI 50, a lower fixing plate III 51, a synchronous belt II 52, a pulley IV 53, a swivel 54, a right vertical plate 55, a shaft IV 56, a lower gear IV 57, a spring II 58, a ring brush I 59, a lower gear V 60, a ring brush II 61, a spring III 62, a shaft V 63, a ring brush III 64, a spring IV 65, a shaft VI 66, a pulley V 67, a lower fixing plate IV 68, a lower gear VI 69, a lower ring gear VI 70, a lower servo motor VII 71, a lower servo motor VIII 72, servo electric cylinders 73, an upper cylinder I 74, an upper fixing plate 75, an upper rack 76, an upper guiding rail 77, a left sliding plate 78, left bearing pedestals 79, left shafts 80, V-shaped rollers 81, a pressure head 82, a cross hinge 83, an upper shaft 84, an upper bearing pedestal 85, an upper lifting plate 86, upper guiding posts 87, upper guiding sleeves 88, upper cylinders II 89, an upper gear 90, right shafts 91, right bearing pedestals 92, a right sliding plate 93, an upper servo motor 94, a synchronous belt III 95, a pulley VI 96, a lower servo motor IX 97 and lower cylinders II 98.
the lower lifting driving system comprises: the four lower guiding sleeves I 4 are fixed below the lower fixing plate I 5; the four lower guiding posts I 2 matching with the four lower guiding sleeves I 4 are fixed below the lower lifting plate I 13; the two lower cylinders II 98 are also fixed on the fixing plate I 5, and the output end thereof is hinged to the lower part of the lower lifting plate I 13; the bearing pedestal I 17 is fixed above the lower lifting plate I 13; the hollow shaft 16 is mounted inside the bearing pedestal I 17 through a bearing; the spline sleeve 15 is mounted inside the hollow shaft 16 through a bearing; the spline shaft 7 is matched with the spline sleeve 15; the pulley II 10 is fixed below the hollow shaft 16; the guard plate 19 is mounted on the top end of the hollow shaft 16 through the ball bowl 18; the material of the portion of the guard plate 19 corresponding to the position of the wheel weight-reducing pit is removed, and the machining part of the wheel flange surface is protected; the lower servo motor I 9 is fixed on the left side below the lower lifting plate I 13 through a transition flange, and the output end thereof is fixed with the pulley III 12; the pulley II 10 and the pulley III 12 are connected by the synchronous belt I 11; the pulley I 8 is fixed below the spline sleeve 15; the lower servo motor IX 97 is fixed on the right side below the lower lifting plate I 13 through a transition flange, and the output end thereof is fixed with the pulley VI 96; the pulley I 8 and the pulley VI 96 are connected by the synchronous belt III 95; the support frame 14 is fixed at the middle position below the lower lifting plate I 13; the lower cylinder I 3 is fixed below the support frame 14, and the output end thereof is connected with the lower end of the rotary joint 6; the upper end of the rotary joint 6 is connected with the lower end of the spline shaft 7; and the center brush 20 is fixed on the top end of the spline shaft 7;
the side brush system comprises: the left vertical plate 26 is fixed on the left side below the guard plate 19; the lower lifting plate II 22 is mounted on the right side of the left vertical plate 26 through the lower guiding rail I 23; the lower rack I 25 is also fixed on the right side of the left vertical plate 26; the lower servo motor III 27 is fixed above the right side of the lower lifting plate II 22, and the output end thereof is fixed with the lower gear I 24; the lower gear I 24 is meshed with the lower rack I 25; the bearing pedestal III 41 is fixed below the right side of the lower lifting plate II 22; the shaft III 40 is mounted inside the bearing pedestal III 41 through a bearing; the lower servo motor II 21 is fixed below the left side of the lower lifting plate II 22, the output end thereof is connected with the left side of the shaft III 40; the lower overturning plate 38 is fixed on the right side of the shaft III 40; the sliding plate I 31 is fixed is mounted above the lower overturning plate 38 through the lower guiding rail II 30; the lower rack II 29 is fixed on the left side of the sliding plate I 31; the lower servo motor V 39 is fixed below the lower overturning plate 38, and the output end thereof is fixed with the lower end gear II 28; the lower gear II 28 is meshed with the lower rack II 29; the bearing pedestal II 36 is fixed above the sliding plate I 31; the shaft II 35 is mounted inside the bearing pedestal II 36 through a bearing; the outer side of the shaft I 33 is matched with the inner hole of the shaft II 35; the spring 34 is mounted in the inner hole above the shaft II 35, and is placed on the lower end of the shaft I 33; the side brush 32 is fixed on the top end of the shaft I 33; and the lower servo motor IV 37 is fixed below the sliding plate I 31, and the output end is connected with the lower end of the shaft II 35;
the ring brush unit comprises: the shaft IV 56 is mounted on the lower fixing plate IV 68 through a bearing; the lower gear IV 57 is fixed on the outer side above the shaft IV 56; the ring brush I 59 is mounted in the hole at the upper end of the shaft IV 56; the spring II 58 is mounted in the inner hole above the shaft IV 56, and is placed on the lower end of the ring brush I 59; the shaft V 63 is mounted on the lower fixing plate IV 68 through the bearing, and is placed on the right side of the shaft IV 56; the lower gear V 60 is fixed on the outer side above the shaft V 63; the ring brush II 61 is mounted in the hole at the upper end of the shaft V 63; the spring III 62 is mounted in the inner hole above the shaft V 63, and is placed on the lower end of the ring brush II 61; the lower gear IV 57 is meshed with the lower gear V 60; and the pulley IV 53 is fixed on the lower end of the shaft V 63; the device comprises two sets of the ring brush units on left and right;
the ring brush system comprises: the lower fixing plate II 44 is fixed on the right side below the guard plate 19 through the right vertical plate 55; the four lower guiding sleeves II 43 are fixed on the lower fixing plate II 44; the four lower guiding posts II 42 matching with the four lower guiding sleeves II 43 are fixed below the lower lifting plate III 45; the two servo electric cylinders 73 are fixed below the lower fixing plate II 44, and the output end thereof is hinged to the lower part of the lower lifting plate III 45; the sliding plate II 49 is mounted above the lower lifting plate III 45 through the lower guiding rail III 48; the lower rack III 47 is fixed above the lower lifting plate III 45; the lower servo motor VI 50 is fixed above the sliding plate II 49, and the output end thereof is fixed with the lower gear III 46; the lower gear III 46 is meshed with the lower rack III 47; the lower fixing plate III 51 is fixed above the sliding plate II 49 through a transition block; the lower fixing plate IV 68 is mounted on the top end of the lower fixing plate III 51 through the swivel 54; the shaft VI 66 is mounted on the lower fixing plate IV 68 through a bearing; the ring brush III 64 is mounted in the hole at the upper end of the shaft VI 66; the spring IV 65 is mounted in the hole at the upper end of the shaft VI 66, and is placed on the lower end of the ring brush; the pulley V 67 is fixed below the shaft VI 66; the lower servo motor VIII 72 is fixed on the lower end of the lower fixing plate III 51, and the output end thereof is connected to the lower part of the shaft VI 66; the pulley IV 53 and the pulley V 67 are connected by the synchronous belt II 52; the lower ring gear VI 70 is fixed to the inner ring of the swivel 54, and the upper end thereof is connected to the lower end of the lower fixing plate IV 68; the lower servo motor VII 71 is fixed on the lower end of the lower fixing plate III 51, and the output end thereof is fixed with the lower gear VI 69; and the lower gear VI 69 is meshed with the lower ring gear VI 70;
the clamping driving system comprises: the left sliding plate 78 and the right sliding plate 93 are respectively mounted above the upper fixing plate 75 through the upper guiding rail 77; the two left bearing pedestals 79 are fixed above the left sliding plate 78; the two left shafts 80 are respectively mounted inside the two left bearing pedestal 79 through bearings; above the two left shafts 80 are respectively fixed with a V-shaped roller 81; the two right bearing pedestals 92 are fixed above the right sliding plate 93; the two right shafts 91 are respectively mounted inside the two right bearing pedestals 92 through bearings; above the two right shaft 91 are respectively fixed with a V-shaped roller 81; the upper servo motor 94 is fixed below the right sliding plate 93, and the output end thereof is connected with the lower part of one of the right shafts 91; the upper cylinder I 74 is fixed above the upper fixing plate 75, and the output end thereof is connected with the left sliding plate 78; the upper gear 90 is fixed above the upper fixing plate 75; the upper sliding plate 78 and the right sliding plate 93 are respectively fixed with the upper rack 76; and the upper rack 76 is meshed with the upper gear 90;
the pressing system comprises: the upper bearing pedestal 85 is fixed below the upper lifting plate 86; the upper shaft 84 is mounted inside the upper bearing pedestal 85 through a bearing; the pressure head 82 is fixed on the lower end of the upper shaft 84 by the cross hinge 83; the four upper guiding posts 87 are fixed above the upper lifting plate 86; the four upper guiding sleeves 88 matching with the upper guiding posts 87 are fixed on the top end of the frame 1; and the two upper cylinders II 89 are fixed on the top end of the frame 1, and the output ends thereof are hinged to the top end of the upper lifting plate 86.
The present disclosure in use is capable of cleaning and removing the burrs on the edges of the drain groove and the weight loss groove at the wheel weight-reducing pit.
The details and operation of the specific device according to the present disclosure will be described below with reference to the accompanying drawings.
The device consists of a frame 1, lower guiding posts I 2, a lower cylinder I 3, lower guiding sleeves I 4, a lower fixing plate I 5, a rotary joint 6, a spline shaft 7, a pulley I 8, a lower servo motor I 9, a pulley II 10, a synchronous belt I 11, a pulley III 12, a lower lifting plate I 13, a support frame 14, a spline sleeve 15, a hollow shaft 16, a bearing pedestal I 17, a ball bowl 18, a guard plate 19, a center brush 20, a lower servo motor II 21, a lower lifting plate II 22, a lower guiding rail I 23, a lower gear I 24, a lower rack I 25, a left vertical plate 26, a lower servo motor III 27, a lower gear II 28, a lower rack II 29, a lower guiding rail II 30, a sliding plate I 31, a side brush 32, a shaft I 33, a spring I 34, a shaft II 35, a bearing pedestal II 36, a lower servo motor IV 37, a lower overturning plate 38, a lower servo motor V 39, a shaft III 40, a bearing pedestal III 41, lower guiding posts II 42, lower guiding sleeves II 43, a lower fixing plate II 44, a lower lifting plate III 45, a lower gear III 46, a lower rack III 47, a lower guiding rail III 48, a sliding plate II 49, a lower servo motor VI 50, a lower fixing plate III 51, a synchronous belt II 52, a pulley IV 53, a swivel 54, a right vertical plate 55, a shaft IV 56, a lower gear IV 57, a spring II 58, a ring brush I 59, a lower gear V 60, a ring brush II 61, a spring III 62, a shaft V 63, a ring brush III 64, a spring IV 65, a shaft VI 66, a pulley V 67, a lower fixing plate IV 68, a lower gear VI 69, a lower ring gear VI 70, a lower servo motor VII 71, a lower servo motor VIII 72, servo electric cylinders 73, an upper cylinder I 74, an upper fixing plate 75, an upper rack 76, an upper guiding rail 77, a left sliding plate 78, left bearing pedestals 79, left shafts 80, V-shaped rollers 81, a pressure head 82, a cross hinge 83, an upper shaft 84, an upper bearing pedestal 85, an upper lifting plate 86, upper guiding posts 87, upper guiding sleeves 88, upper cylinders II 89, an upper gear 90, right shafts 91, right bearing pedestals 92, a right sliding plate 93, an upper servo motor 94, a synchronous belt III 95, a pulley VI 96, a lower servo motor IX 97 and lower cylinders II 98.
The lower lifting driving system comprises: the four lower guiding sleeves I 4 are fixed below the lower fixing plate I 5; the four lower guiding posts I 2 matching with the four lower guiding sleeves I 4 are fixed below the lower lifting plate I 13; the two lower cylinders II 98 are also fixed on the fixing plate I 5, and the output end thereof is hinged to the lower part of the lower lifting plate I 13; the bearing pedestal I 17 is fixed above the lower lifting plate I 13; the hollow shaft 16 is mounted inside the bearing pedestal I 17 through a bearing; the spline sleeve 15 is mounted inside the hollow shaft 16 through a bearing; the spline shaft 7 is matched with the spline sleeve 15; the pulley II 10 is fixed below the hollow shaft 16; the guard plate 19 is mounted on the top end of the hollow shaft 16 through the ball bowl 18; the material of the portion of the guard plate 19 corresponding to the position of the wheel weight-reducing pit is removed, and the machining part of the wheel flange surface is protected; the lower servo motor I 9 is fixed on the left side below the lower lifting plate I 13 through a transition flange, and the output end thereof is fixed with the pulley III 12; the pulley II 10 and the pulley III 12 are connected by the synchronous belt I 11; the pulley I 8 is fixed below the spline sleeve 15; the lower servo motor IX 97 is fixed on the right side below the lower lifting plate I 13 through a transition flange, and the output end thereof is fixed with the pulley VI 96; the pulley I 8 and the pulley VI 96 are connected by the synchronous belt III 95; the support frame 14 is fixed at the middle position below the lower lifting plate I 13; the lower cylinder I 3 is fixed below the support frame 14, and the output end thereof is connected with the lower end of the rotary joint 6; the upper end of the rotary joint 6 is connected with the lower end of the spline shaft 7; and the center brush 20 is fixed on the top end of the spline shaft 7.
The side brush system comprises: the left vertical plate 26 is fixed on the left side below the guard plate 19; the lower lifting plate II 22 is mounted on the right side of the left vertical plate 26 through the lower guiding rail I 23; the lower rack I 25 is also fixed on the right side of the left vertical plate 26; the lower servo motor III 27 is fixed above the right side of the lower lifting plate II 22, and the output end thereof is fixed with the lower gear I 24; the lower gear I 24 is meshed with the lower rack I 25; the bearing pedestal III 41 is fixed below the right side of the lower lifting plate II 22; the shaft III 40 is mounted inside the bearing pedestal III 41 through a bearing; the lower servo motor II 21 is fixed below the left side of the lower lifting plate II 22, the output end thereof is connected with the left side of the shaft III 40; the lower overturning plate 38 is fixed on the right side of the shaft III 40; the sliding plate I 31 is fixed is mounted above the lower overturning plate 38 through the lower guiding rail II 30; the lower rack II 29 is fixed on the left side of the sliding plate I 31; the lower servo motor V 39 is fixed below the lower overturning plate 38, and the output end thereof is fixed with the lower end gear II 28; the lower gear II 28 is meshed with the lower rack II 29; the bearing pedestal II 36 is fixed above the sliding plate I 31; the shaft II 35 is mounted inside the bearing pedestal II 36 through a bearing; the outer side of the shaft I 33 is matched with the inner hole of the shaft II 35; the spring 34 is mounted in the inner hole above the shaft II 35, and is placed on the lower end of the shaft I 33; the side brush 32 is fixed on the top end of the shaft I 33; and the lower servo motor IV 37 is fixed below the sliding plate I 31, and the output end is connected with the lower end of the shaft II 35.
The ring brush unit comprises: the shaft IV 56 is mounted on the lower fixing plate IV 68 through a bearing; the lower gear IV 57 is fixed on the outer side above the shaft IV 56; the ring brush I 59 is mounted in the hole at the upper end of the shaft IV 56; the spring II 58 is mounted in the inner hole above the shaft IV 56, and is placed on the lower end of the ring brush I 59; the shaft V 63 is mounted on the lower fixing plate IV 68 through the bearing, and is placed on the right side of the shaft IV 56; the lower gear V 60 is fixed on the outer side above the shaft V 63; the ring brush II 61 is mounted in the hole at the upper end of the shaft V 63; the spring III 62 is mounted in the inner hole above the shaft V 63, and is placed on the lower end of the ring brush II 61; the lower gear IV 57 is meshed with the lower gear V 60; and the pulley IV 53 is fixed on the lower end of the shaft V 63; the device comprises two sets of the ring brush units on left and right.
The ring brush system comprises: the lower fixing plate II 44 is fixed on the right side below the guard plate 19 through the right vertical plate 55; the four lower guiding sleeves II 43 are fixed on the lower fixing plate II 44; the four lower guiding posts II 42 matching with the four lower guiding sleeves II 43 are fixed below the lower lifting plate III 45; the two servo electric cylinders 73 are fixed below the lower fixing plate II 44, and the output end thereof is hinged to the lower part of the lower lifting plate III 45; the sliding plate II 49 is mounted above the lower lifting plate III 45 through the lower guiding rail III 48; the lower rack III 47 is fixed above the lower lifting plate III 45; the lower servo motor VI 50 is fixed above the sliding plate II 49, and the output end thereof is fixed with the lower gear III 46; the lower gear III 46 is meshed with the lower rack III 47; the lower fixing plate III 51 is fixed above the sliding plate II 49 through a transition block; the lower fixing plate IV 68 is mounted on the top end of the lower fixing plate III 51 through the swivel 54; the shaft VI 66 is mounted on the lower fixing plate IV 68 through a bearing; the ring brush III 64 is mounted in the hole at the upper end of the shaft VI 66; the spring IV 65 is mounted in the hole at the upper end of the shaft VI 66, and is placed on the lower end of the ring brush; the pulley V 67 is fixed below the shaft VI 66; the lower servo motor VIII 72 is fixed on the lower end of the lower fixing plate III 51, and the output end thereof is connected to the lower part of the shaft VI 66; the pulley IV 53 and the pulley V 67 are connected by the synchronous belt II 52; the lower ring gear VI 70 is fixed to the inner ring of the swivel 54, and the upper end thereof is connected to the lower end of the lower fixing plate IV 68; the lower servo motor VII 71 is fixed on the lower end of the lower fixing plate III 51, and the output end thereof is fixed with the lower gear VI 69; and the lower gear VI 69 is meshed with the lower ring gear VI 70.
The clamping driving system comprises: the left sliding plate 78 and the right sliding plate 93 are respectively mounted above the upper fixing plate 75 through the upper guiding rail 77; the two left bearing pedestals 79 are fixed above the left sliding plate 78; the two left shafts 80 are respectively mounted inside the two left bearing pedestal 79 through bearings; above the two left shafts 80 are respectively fixed with a V-shaped roller 81; the two right bearing pedestals 92 are fixed above the right sliding plate 93; the two right shafts 91 are respectively mounted inside the two right bearing pedestals 92 through bearings; above the two right shaft 91 are respectively fixed with a V-shaped roller 81; the upper servo motor 94 is fixed below the right sliding plate 93, and the output end thereof is connected with the lower part of one of the right shafts 91; the upper cylinder I 74 is fixed above the upper fixing plate 75, and the output end thereof is connected with the left sliding plate 78; the upper gear 90 is fixed above the upper fixing plate 75; the upper sliding plate 78 and the right sliding plate 93 are respectively fixed with the upper rack 76; and the upper rack 76 is meshed with the upper gear 90.
The pressing system comprises: the upper bearing pedestal 85 is fixed below the upper lifting plate 86; the upper shaft 84 is mounted inside the upper bearing pedestal 85 through a bearing; the pressure head 82 is fixed on the lower end of the upper shaft 84 by the cross hinge 83; the four upper guiding posts 87 are fixed above the upper lifting plate 86; the four upper guiding sleeves 88 matching with the upper guiding posts 87 are fixed on the top end of the frame 1; and the two upper cylinders II 89 are fixed on the top end of the frame 1, and the output ends thereof are hinged to the top end of the upper lifting plate 86.
During operation, the upper cylinder I 74 causes the four V-shaped rollers 81 to synchronously clamp the wheel through the upper gear 90, the upper rack 76 and the upper guiding rail 77; the upper cylinder II 89 make the pressure head 82 press the wheel riser through the upper guiding posts 87 and the upper guiding sleeves 88; the upper servo motor 94 rotates the clamped wheel through the right shaft 91; the lower servo motor IX 97 drives the spline sleeve 15 to rotate through the pulley I 8, the pulley VI 96 and the synchronous belt III 95; through the cooperation of the sleeve 15 with the spline shaft 7, the spline shaft 7 and the center brush 20 can be driven to rotate; the lower servo motor I 9 drives the hollow shaft 16 and the guard plate 19 to rotate through the pulley II 10, the pulley III 12 and the synchronous belt I 11, and the rotation will be stopped when the guard plate 19 corresponds to the position of the weight-reducing pit of the wheel; the lower cylinder II 98 tightly fits the upper end surface of the guard plate 19 with the wheel flange through the lower guiding posts I 2 and the lower guiding sleeves I 4; and at this time, the center bush 20 can remove the burrs at the center hole of the wheel, and the height of the center brush 20 can be adjusted by the lower cylinder I 3 for different wheels.
The lower servo motor IV 37 can drive the side brush 32 to rotate through the shaft II 35; the side brush 32 can be floated up and down by the spring I 34; the lower servo motor V 39 can achieve the adjustment of the left and right positions of the side brush 32 through the lower gear II 28, the lower rack II 29 and the lower guiding rail II 30; the lower servo motor III 27 can achieve the adjustment of the upper and lower positions of the side brush 32 through the lower gear I 24, the lower rack I 25 and the lower guiding rail I 23; and the lower servo motor II 21 can achieve the adjustment of the front and rear angles of the side brush 32 through the shaft III 40. The burrs at the edge of the drain groove can be removed when the rotating brush 32 contacts the wheel weight-reducing pit.
The lower servo motor VIII 72 can drive the pulley V 67 and the ring brush III 64 to rotate through the shaft VI 66; the spring IV 65 can achieve the floating of the ring brush III 64; the pulley V 67 can drive the pulley IV 53 and the shaft V 63 to rotate through the synchronous belt II 52; the shaft V 63 can drive the ring brush II 61 to rotate; the spring III 62 can achieve the floating of the ring brush II 61; the lower gear V 60 can drive the shaft IV 56 and the ring brush I 59 to rotate by meshing with the lower gear IV 57; the spring II 58 can achieve the floating of the ring brush I 59; the lower servo motor VII 71 can achieve the adjustment of the angles of the lower fixing plate IV 68 and each ring brush through the lower gear VI 69, the lower ring gear VI 70 and the swivel 54; the lower servo motor VI 50 can achieve the adjustment of the left and right positions of the lower fixing plate IV 68 and each ring brush through the lower gear III 46, the lower rack III 47 and the lower guiding rail III 48; and the servo electric cylinder 73 can achieve the adjustment of the upper and lower positions of the lower fixing plate IV 68 and each ring brush through the lower guiding posts II 42 and the lower guiding sleeves II 43. The burrs at the edge of the weight loss groove can be removed when the rotating brush contacts the wheel weight-reducing pit.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201811313316.0 | Nov 2018 | CN | national |
