External circulation ball screw with built-in reverser

Abstract

The external circulation ball screw comprises a screw rod, a nut, four steel ball reversers, two guide pipes and steel balls, the four steel ball reversers are all detachably installed on the nut, the two ends of each guide pipe are detachably connected with the two steel ball reversers respectively, and the two steel ball reversers are detachably installed on the nut. Any ends of the two guide pipes are located in the steel ball reversers at the two ends respectively, the corresponding guide pipes and the steel ball reversers form outer circulation roller paths, each guide pipe comprises two guide pipe pieces, and the two guide pipe pieces are buckled to form the guide pipe. The two guide pipe pieces are buckled to form the guide pipe and the independently-arranged steel ball reverser, so that the path of the steel ball can be conveniently designed, the motion characteristic of the steel ball in a loop can be conveniently optimized, and the impact of the steel ball on the steel ball reverser is reduced; the nut and the screw rod form the inner spiral raceway, meanwhile, production can be conveniently carried out through casting, forging and other production modes, the production efficiency is improved, and the cost is saved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of automobile manufacturing, especially to a built-in reversing device external circulation ball screw. BACKGROUND

[0002] With the development of intelligent driving of automobile, the electric power steering system is booming. The demand for large load electric power steering gear of commercial vehicle is increasing. As the most widely used scheme of electric power steering gear of commercial vehicle, the ball screw scheme used in the electric circulating ball steering gear has many advantages such as large transmission ratio, high bearing capacity, high transmission efficiency, low noise and smooth transmission. However, with the increase of front axle load of pure electric commercial vehicle, the steering force of the steering gear also needs to be increased, so higher requirements are put forward for the bearing capacity of the ball screw. At the same time, with the gradual increase of the demand for driving comfort of commercial vehicle drivers, the transmission smoothness and noise of the ball screw also need to be further improved.

[0003] The ball screw used in the existing circulating ball steering gear is in the form of internal circulation or external circulation. The reversing device of the internal circulation ball screw has high cost, and the effective raceway on the side where the reversing device is arranged is reduced, which affects the bearing capacity, so it is mainly used in the transmission of steering gear with small load. The existing external circulation ball screw mainly uses the plug-in pipe scheme, and the guide pipe is formed by stamping, which has low cost. However, since the guide pipe is formed by stamping cold-rolled sheet, the shape design of the guide pipe on the guiding part of the steel ball is difficult to optimize. At the position where the steel ball reverses, the guide pipe is easy to be impacted and extruded by the steel ball, which destroys the shape of the guide pipe, causes the steel ball to be stuck at the reversing position, and leads to the failure of the ball screw.

[0004] In order to meet the demand for large load steering gear, there are guide pipes on the market, which are formed by stamping sheet metal and then cut and polished manually, or formed by additive manufacturing and then polished. These schemes can more accurately control the path of the steel ball and improve the impact resistance of the guide pipe, thereby improving the bearing capacity and transmission stability of the ball screw and reducing noise. However, the cost of these schemes is difficult to compress in batch production, which is not conducive to the application of mass-produced products.

[0005] Therefore, the utility model is proposed to solve the above technical problems. UTILITY MODEL CONTENTS

[0006] The utility model aims at providing a built-in reversing device external circulation ball screw to solve the technical problem that the shape design of the guide part of the existing external circulation ball screw is difficult to optimize.

[0007] The technical scheme of the utility model is as follows: a built-in reversing device external circulation ball screw comprises:

[0008] A screw rod is connected with an external driving mechanism at either end of the screw rod.

[0009] The nut is sleeved on the screw rod, the nut is in clearance fit with the screw rod, and an inner spiral raceway is formed between the nut and the screw rod;

[0010] The four steel ball reversers are detachably installed on the nut.

[0011] The two conduits are detachably connected with the two steel ball reversers at two ends respectively, and any end of the two conduits is located in the steel ball reverser at the two ends respectively, and the corresponding conduit and the steel ball reverser form an outer circulation raceway, and the conduit comprises two conduit pieces which are buckled to form the conduit.

[0012] The steel ball can enter the outer circulation raceway from the inner spiral raceway, and the steel ball can also enter the inner spiral raceway from the outer circulation raceway.

[0013] Further, the steel ball reverser comprises a snap ring.

[0014] The snap ring is provided with a tongue plate penetrating through the snap ring.

[0015] The bottom of the tongue plate is provided with an arc-shaped groove which is matched with the screw groove of the screw rod, and the arc-shaped groove is used for guiding the steel ball.

[0016] Further, four conduit holes are formed through the nut.

[0017] Of which, two conduit holes are located at two ends of the length direction of the nut, and the other two conduit holes are located between the two ends of the length direction of the nut.

[0018] The four steel ball reversers are detachably arranged in the four conduit holes.

[0019] Further, two conduit pressing blocks are further included.

[0020] The two conduit pressing blocks cover the two conduits respectively.

[0021] The conduit pressing blocks are fixed on the nut by bolts.

[0022] Further, the conduit can be one, when the conduit is one, the conduit hole and the steel ball reverser are two, and the conduit pressing block is one, and at this time, the outer circulation raceway and the inner spiral raceway form a single circulation loop.

[0023] Further, the nut is provided with a straight-toothed rack at the bottom, and the straight-toothed rack is used for transmitting power to an external gear.

[0024] By adopting the above technical scheme, the utility model has the following beneficial effects:

[0025] The two guide pipe pieces are buckled to form the guide pipe and the independently arranged steel ball reverser, so that the path of the steel ball is facilitated to be designed, the motion characteristics of the steel ball in the loop are facilitated to be optimized, the impact of the steel ball on the steel ball reverser is reduced, and the motion noise is also reduced.

[0026] The two guide pipes and the steel ball reverser form an outer circulating raceway, the nut and the screw rod form an inner spiral raceway, the smoothness of transmission is improved, meanwhile, the production is facilitated through casting, forging and other production modes, the strength and toughness of the steel ball reverser are enhanced, the impact and extrusion of the steel ball under a large load can be borne, the working life of the ball screw under a large load is ensured, the production efficiency is improved, and the cost is saved. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are part of this application and serve to provide a further understanding of the present application, the schematic embodiments of the present application and the description thereof serve to explain the present application, but do not constitute an improper limitation on the present application. Obviously, the drawings described below are only some embodiments, and other drawings can be obtained by those skilled in the art without creative labor. In the drawings:

[0028] Figure 1 A front view of the built-in reverser outer circulating ball screw provided by the present application;

[0029] Figure 2 A Figure 1 A sectional view of the built-in reverser outer circulating ball screw provided by the present application;

[0030] Figure 3 A structure schematic diagram of the built-in reverser outer circulating ball screw provided by the present application without a nut;

[0031] Figure 4 A structure schematic diagram of a single circulating loop of the built-in reverser outer circulating ball screw provided by the present application;

[0032] Figure 5 An assembly schematic diagram of the steel ball reverser and the guide pipe of the built-in reverser outer circulating ball screw provided by the present application;

[0033] Figure 6 A Figure 5 An exploded view.

[0034] Reference signs: 1, first guide pipe; 2, guide pipe pressing block; 3, second guide pipe; 4, nut; 5, screw rod; 6, steel ball; 7, steel ball reverser.

[0035] It should be noted that the drawings and the written description are not intended to limit the scope of the inventive concept in any way, but are merely to illustrate the inventive concept to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0036] The specific embodiments of the present application will be further described in detail with reference to the accompanying drawings.

[0037] Referring to Figures 1 to 6 As shown in the drawings, the embodiment of the present application provides an inner built-in reversing device outer circulation ball screw, which comprises a screw rod 5, a nut 4, four steel ball reversing devices 7, two pipes and steel balls 6, the screw rod 5 is connected with an external driving mechanism at either end, the nut 4 is sleeved on the screw rod 5, the nut 4 is gap-fitted with the screw rod 5, an inner spiral raceway is formed between the nut 4 and the screw rod 5, the four steel ball reversing devices 7 are all detachably installed on the nut 4, the two ends of each pipe are respectively detachably connected with two steel ball reversing devices 7, and any end of the two pipes is located in the steel ball reversing device 7 at the two ends respectively, the corresponding pipe and the steel ball reversing device 7 form an outer circulation raceway, the pipe comprises two pipe pieces, the two pipe pieces are buckled to form the pipe, the steel ball 6 can enter the outer circulation raceway from the inner spiral raceway, and the steel ball 6 can also enter the inner spiral raceway from the outer circulation raceway.

[0038] It should be noted that the screw rod 5 is fixed through bearings at both ends; the nut 4 is limited by a limiting mechanism, so that the nut 4 can only slide and cannot rotate, the limiting mechanism can be a limiting block, the limiting block is arranged on the two sides of the nut 4, and the nut 4 and the limiting block are frictionally connected; or the limiting mechanism can be a limiting rod, at least two limiting rods are arranged through the nut 4, and the nut 4 and the limiting rod are slidingly connected. The screw rod 5, the nut 4 and the steel ball 6 can be processed by using a mature processing mode, and are machined after die forming. The pipe is made of metal or non-metal material and is processed by stamping forming, injection molding and the like, the steel ball reversing device 7 is independently structured and designed, and can be produced by using a die forming production mode, and is made of metal, non-metal and the like and is produced by casting, forging, injection molding and the like.

[0039] Further, the outer circulation raceway and the inner spiral raceway form a double circulation loop, at this time, the two pipes are a first pipe 1 and a second pipe 3, and the first pipe 1 and the second pipe 3 are both arranged obliquely.

[0040] In the above scheme, the two guide pipe pieces are buckled to form the guide pipe and the independently arranged steel ball reverser 7, so that the path of the steel ball 6 is facilitated to be designed, the motion characteristics of the steel ball 6 in the loop are facilitated to be optimized, the impact of the steel ball 6 on the steel ball reverser 7 is reduced, the motion noise is also reduced, the two guide pipes and the steel ball reverser 7 form an outer circulating raceway, the nut 4 and the screw rod 5 form an inner spiral raceway, the smoothness of the transmission is improved, at the same time, the production is facilitated to be carried out through casting, forging and the like, the strength and toughness of the steel ball reverser 7 are enhanced, the impact and extrusion of the steel ball 6 under a large load can be borne, the working life of the ball screw provided in the embodiment is guaranteed under a large load, the production efficiency is improved, and the cost is saved.

[0041] In some possible embodiments, referring to Figure 5 and Figure 6 shown, the steel ball reverser 7 includes a snap ring, the bottom of the snap ring is provided with a tongue plate, the tongue plate penetrates through the snap ring, the bottom of the tongue plate has an arc-shaped groove, the arc-shaped groove cooperates with the screw groove of the screw rod 5, and the arc-shaped groove is used for guiding the steel ball 6.

[0042] In the above scheme, the steel ball 6 moves in the inner spiral raceway, is blocked by the tongue plate of the steel ball reverser 7 when leaving the inner spiral raceway, is extruded into the outer circulating raceway by the rear steel ball 6, and then enters the inner spiral raceway through the other side of the steel ball reverser 7 after passing through the outer circulating raceway. The independent steel ball reverser 7 design facilitates to improve the mechanical properties of the steel ball reverser 7, and the steel ball reverser 7 can be produced in a mold forming manner. The steel ball reverser 7 is a general piece, in the design, for the same parameter ball screw, the position of the steel ball 6 out of the inner spiral raceway is determined, the structure of the steel ball reverser 7 is determined, and the steel ball reverser 7 can be used for platform product.

[0043] In some possible embodiments, referring to Figure 3 shown, four guide pipe holes (not shown in the figure) are provided through the nut 4, two guide pipe holes are located at two ends of the length direction of the nut 4, and the other two guide pipe holes are located between the two ends of the length direction of the nut 4. Four steel ball reversers 7 are respectively detachably arranged in the four guide pipe holes.

[0044] In some possible embodiments, referring to Figure 1 and Figure 2 shown, the ball screw provided in the embodiment further includes two guide pipe pressing blocks 2, the two guide pipe pressing blocks 2 cover two guide pipes respectively, the guide pipe pressing blocks 2 are fixed on the nut 4 through bolts, and are used for fixing the guide pipes.

[0045] In some possible embodiments, referring to Figure 4As shown, the conduit can be provided as one, when the conduit is one, the conduit hole and the steel ball reverser 7 are two, the conduit pressing block 2 is one, at this time the outer circulating raceway and the inner spiral raceway form a single circulating loop.

[0046] In some possible embodiments, referring to Figure 1 With Figure 2 As shown, the nut 4 is provided with a straight toothed rack at the bottom, which is used to transmit power to the external gear.

[0047] When assembling, first, the screw rod 5 is installed into the nut 4, so that the two screw grooves are aligned, then the steel ball reverser 7 is inserted into the conduit hole on the nut 4, and then the steel balls 6 are sequentially placed into the ball screw, and gradually all the steel balls 6 are screwed into the screw grooves, then the first conduit 1 is inserted into the snap ring at the upper end of the steel ball reverser 7, the steel balls 6 are filled into the conduit 1, then the second conduit 3 is inserted into the snap ring at the upper end of the other steel ball reverser 7, at this time, the two conduit pressing blocks 2 are used to press the first conduit 1 and the second conduit 3 respectively.

[0048] Through the ball screw provided by the embodiment of the application, the trajectory optimization of the steel balls 6 can be facilitated, the mechanical properties of the steel ball reverser 7 can be improved, batch production can be easily carried out, the load capacity of the ball screw can be improved, the working life can be improved, the working smoothness can be improved, the working noise can be reduced, the transmission efficiency can be improved, the production efficiency of the steel ball reverser 7 and the conduit can be improved and the manufacturing cost can be reduced.

[0049] The specific embodiment is only an explanation of the utility model, and is not a limitation of the utility model, and those skilled in the art can make modifications to the embodiment without creative contribution according to the needs after reading the specification, but as long as it is within the protection scope of the utility model, it is protected by the patent law.

Claims

1. A built-in diverter outer loop ball screw, characterized by, It comprises: a screw rod (5) connected with an external driving mechanism at either end; a nut (4) sleeved on the screw rod (5), the nut (4) being in clearance fit with the screw rod (5), and an inner spiral raceway being formed between the nut (4) and the screw rod (5); four steel ball reversers (7), each of which is detachably installed on the nut (4); two guide pipes, each of which is detachably connected with two steel ball reversers (7) at two ends, and each of which is located in the steel ball reverser (7) at either end, the corresponding guide pipe and the steel ball reverser (7) forming an outer circulation raceway, the guide pipe comprising two guide pipe pieces, the two guide pipe pieces being buckled to form the guide pipe; a steel ball (6) which can enter the outer circulation raceway from the inner spiral raceway and vice versa.

2. The built-in diverter external circulation ball screw according to claim 1, wherein The steel ball reverser (7) comprises a snap ring; the bottom of the snap ring is provided with a tongue plate which penetrates through the snap ring; the bottom of the tongue plate is provided with an arc-shaped groove which is matched with the screw groove of the screw rod (5), and the arc-shaped groove is used for guiding the steel ball (6).

3. The built-in diverter external circulation ball screw according to claim 1, wherein Four guide pipe holes are formed through the nut (4); two of the guide pipe holes are located at the two ends of the length direction of the nut (4), and the other two are located between the two ends of the length direction of the nut (4); four steel ball reversers (7) are detachably arranged in the four guide pipe holes.

4. The built-in diverter external circulation ball screw according to claim 3, wherein It further comprises two guide pipe pressing blocks (2); the two guide pipe pressing blocks (2) cover the two guide pipes respectively; the guide pipe pressing blocks (2) are fixed on the nut (4) by bolts.

5. The built-in diverter external circulation ball screw according to claim 4, wherein The guide pipe can be one, when the guide pipe is one, the guide pipe hole and the steel ball reverser (7) are two, and the guide pipe pressing block (2) is one, at this time, the outer circulation raceway and the inner spiral raceway form a single circulation loop.

6. The built-in diverter external circulation ball screw according to claim 4, wherein The bottom of the nut (4) is provided with a straight-toothed rack which is used for transmitting power to an external gear.

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