Clearance compensation mechanism, worm and gear transmission device and electric power steering system

Abstract

The utility model relates to the technical field of worm and gear transmission, and provides a clearance compensation mechanism, a worm and gear transmission device and an electric power steering system. The backlash compensation mechanism comprises a fixed part and a fixed part, wherein the fixed part is provided with a cavity with an opening; the first section of the ejector rod is assembled in the cavity in a reciprocating motion mode through an elastic piece and is in clearance fit with the cavity, a spiral groove extending from one end to the other end is formed in the outer wall of the first section of the ejector rod, and the second section of the ejector rod extends out of the cavity. According to the clearance compensation mechanism, in the process that the ejector rod is assembled to the fixing piece, air in the cavity of the fixing piece can be smoothly exhausted through the spiral groove of the ejector rod, so that it is guaranteed that the ejector rod and the fixing piece are accurately matched after assembly is completed, and then the clearance adjusting capacity of the clearance compensation mechanism is guaranteed; the spiral groove further has an oil storage function, so that the first section of the ejector rod is matched with the cavity of the fixing piece smoothly, and lubrication and noise reduction in the movement process of the ejector rod are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of worm gear transmission, in particular to a clearance compensation mechanism, a worm gear transmission device and an electric power steering system. Background Art

[0002] During the worm gear transmission process, there is a gap between the two, which will cause noise and affect the transmission stability. Therefore, a gap compensation mechanism is needed to adjust the gap between the worm wheel and the worm.

[0003] The clearance compensation mechanism usually includes a fixing part and a push rod which is gap-assembled in the cavity of the fixing part. The fixing part is assembled with the housing of the worm gear transmission device. The push rod supports the bearing assembled at the end of the worm. The push rod can reciprocate to keep the clearance between the worm wheel and the worm within a reasonable range.

[0004] The existing gap compensation mechanism has at least the following problems: since the fitting clearance between the push rod and the fixing part is small (in order to ensure the stability of the push rod), the air in the cavity of the fixing part cannot be discharged during the process of assembling the push rod to the fixing part, which will affect the fitting relationship between the push rod and the fixing part, and further affect the gap adjustment ability of the gap compensation mechanism.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the utility model, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content

[0006] In view of this, the utility model provides a clearance compensation mechanism, a worm gear transmission device and an electric power steering system, which can at least solve the problem that the air in the cavity of the fixing part cannot be discharged during the process of assembling the push rod to the fixing part, ensure the accurate fit between the push rod and the fixing part after the assembly is completed, and further ensure the clearance adjustment ability of the clearance compensation mechanism.

[0007] One aspect of the utility model provides a clearance compensation mechanism for a worm gear transmission device, comprising: a fixing member, a cavity provided with an opening; a push rod, a first section of the push rod being reciprocatingly assembled in the cavity through an elastic member and cooperating with the clearance between the cavities, an outer wall of the first section of the push rod being provided with a spiral groove extending from one end to the other end, and a second section of the push rod extending out of the cavity.

[0008] In some embodiments, the number of spiral turns of the spiral groove is between one and two.

[0009] In some embodiments, the fixing member is formed as a nut with external threads.

[0010] In some embodiments, a cross groove is provided on the top of the nut.

[0011] In some embodiments, the end surface edge of the first section of the push rod is provided with a chamfer, and an oil storage cavity is formed between the chamfer and the top corner of the cavity.

[0012] In some embodiments, the first section of the push rod is provided with a receiving cavity, and the elastic member is received in the receiving cavity and abuts against the top wall of the cavity and the bottom wall of the receiving cavity respectively.

[0013] Another aspect of the utility model provides a worm gear transmission device, comprising: a worm wheel and a worm arranged in a housing and meshing with each other, the two ends of the worm being supported by a first bearing and a second bearing respectively, the first bearing being assembled with the housing; a retaining frame, at least sleeved outside a portion of the second bearing and assembled with the housing, the retaining frame limiting the second bearing in a first radial direction, and the retaining frame being provided with a gap adjustment through hole along a second radial direction, the second radial direction being perpendicular to the first radial direction and to an extension direction of the worm; a gap compensation mechanism as described in any of the above embodiments, the fixing part of the gap compensation mechanism being assembled with the housing, the second section of the top rod of the gap compensation mechanism passing through the gap adjustment through hole and abutting against the second bearing.

[0014] In some embodiments, the retaining frame is formed as a C-shaped ring, both ends of the C-shaped ring are in contact with the second bearing to limit the second bearing, the gap adjustment through hole is set at the bottom of the C-shaped ring, and a gap is reserved between the bottom area of ​​the C-shaped ring and the second bearing.

[0015] In some embodiments, the C-shaped ring includes a plastic frame and a rubber buffer layer disposed outside the plastic frame.

[0016] Another aspect of the present invention provides an electric power steering system, wherein the electric power steering system is equipped with a worm gear transmission device as described in any of the above embodiments.

[0017] Compared with the prior art, the beneficial effects of the present invention include at least:

[0018] The gap compensation mechanism of the utility model is provided with a spiral groove extending from one end to the other end on the outer wall of the first section of the push rod, so that when the push rod is assembled to the fixing part, the air in the cavity of the fixing part can be smoothly discharged by utilizing the spiral groove, so as to ensure the accurate fit between the push rod and the fixing part after the assembly is completed, avoid the blockage caused by holding the air when the push rod slides in the cavity, and thus ensure the gap adjustment ability of the gap compensation mechanism; the spiral groove also has an oil storage function, so that the first section of the push rod and the cavity of the fixing part can fit smoothly, so as to achieve lubrication and noise reduction during the movement of the push rod.

[0019] When the gap compensation mechanism of the utility model is used in a worm gear transmission device, the fixing part is assembled with the housing of the worm gear transmission device, and the second section of the push rod is supported by the bearing assembled at the end of the worm. The first section of the push rod is reciprocatingly assembled in the cavity of the fixing part through the elastic part and matched with the gap between the cavities, so that the push rod always supports the bearing stably with appropriate force, so that the gap between the worm wheel and the worm is kept in a reasonable range. In addition, during the adjustment of the gap of the push rod, the oil storage function of the spiral groove is used to achieve lubrication and noise reduction.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present utility model, and together with the specification, are used to explain the principles of the present utility model. Obviously, the drawings described below are only some embodiments of the present utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 A schematic cross-sectional view of the gap compensation mechanism in an embodiment of the utility model is shown;

[0023] Figure 2 and Figure 3 The exploded structural diagram of the gap compensation mechanism in the embodiment of the utility model is shown;

[0024] Figure 4 A schematic diagram of the top view of the fixing member of the gap compensation mechanism in the embodiment of the utility model is shown;

[0025] Figure 5 A partial structural schematic diagram of a worm gear transmission device in an embodiment of the utility model is shown;

[0026] Figure 6 A schematic diagram of the matching structure of the retainer and housing, the second bearing and the clearance compensation mechanism of the worm gear transmission device in the embodiment of the utility model is shown. DETAILED DESCRIPTION

[0027] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.

[0028] The words "first", "second" and similar words used in the specific description do not indicate any order, quantity or importance, but are only used to distinguish different components. In addition, in the description of the present invention, the directions or positional relationships indicated by the terms "radial", "circumferential", "top", "bottom" and the like are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in different embodiments may be combined with each other.

[0030] Figure 1 The cross-sectional structure of the gap compensation mechanism in the embodiment of the utility model is shown. Figure 2 and Figure 3 The exploded structure of the gap compensation mechanism in the embodiment of the utility model is shown in FIG. Figure 4 The top view structure of the fixing member of the gap compensation mechanism in the embodiment of the utility model is shown; Figures 1 to 4 As shown, the gap compensation mechanism 100 provided by the embodiment of the utility model includes:

[0031] The fixing member 110 is provided with a cavity 111 having an opening;

[0032] The push rod 120, the first section 120a of the push rod 120 is reciprocatingly assembled in the cavity 111 through the elastic member 130, and is gap-matched with the cavity 111, the outer wall of the first section 120a of the push rod 120 is provided with a spiral groove 122 extending from one end to the other end, and the second section 120b of the push rod 120 extends out of the cavity 111.

[0033] The gap compensation mechanism 100 of the utility model is provided with a spiral groove 122 extending from one end to the other end on the outer wall of the first section 120a of the push rod 120, so that when the push rod 120 is assembled to the fixing part 110, the air in the cavity 111 of the fixing part 110 is smoothly discharged by using the spiral groove 122, so as to ensure that the push rod 120 and the fixing part 110 are accurately matched after the assembly is completed, and the air holding and blockage caused when the push rod 120 slides in the cavity 111 are avoided, thereby ensuring the gap adjustment ability of the gap compensation mechanism 100; the spiral groove 122 also has an oil storage function, so that the first section 120a of the push rod 120 and the cavity 111 of the fixing part 110 are smoothly matched, so as to ensure lubrication and noise reduction during the movement of the push rod 120.

[0034] The matching clearance between the first section 120a of the push rod 120 and the cavity 111 is preferably between 0.03 mm and 0.05 mm, which ensures that the push rod 120 is stable and does not shake, and allows the push rod 120 to slide and reciprocate in the cavity 111. In addition, the push rod 120 can be made of metal to ensure its structural strength.

[0035] When the gap compensation mechanism 100 of the utility model is used for a worm gear transmission device, the fixing member 110 is assembled with the housing of the worm gear transmission device, and the second section 120b of the push rod 120 is supported by the bearing assembled at the end of the worm. The first section 120a of the push rod 120 is reciprocatingly assembled in the cavity 111 of the fixing member 110 through the elastic member 130, and the design of the clearance between the push rod 120 and the cavity 111 is matched, so that the push rod 120 always supports the bearing stably with appropriate force, so that the clearance between the worm wheel and the worm is maintained in a reasonable range. In addition, during the clearance adjustment process of the push rod 120, the oil storage function of the spiral groove 122 is used to achieve lubrication and noise reduction.

[0036] In some embodiments, the number of spiral turns of the spiral groove 122 is between one and two. The number of spiral turns is greater than or equal to one, ensuring that the grease is evenly distributed in the cavity 111 in the circumferential direction to achieve lubrication and noise reduction during the movement of the ejector 120; the number of spiral turns is less than or equal to two, ensuring that the air in the cavity 111 is discharged smoothly during the assembly of the ejector 120, avoiding excessive spiral turns that hinder air discharge.

[0037] In some embodiments, the end surface of the second section 120b of the push rod 120 is designed to be spherical, which can eliminate the unbalanced load caused by processing and assembly, so that the second section 120b of the push rod 120 always stably abuts against the bearing when the gap compensation mechanism 100 is assembled to the worm gear transmission device.

[0038] In some embodiments, the fixing member 110 is formed as a nut with an external thread 118. In this way, when the clearance compensation mechanism 100 is used in a worm gear transmission device, the fixing member 110 can be screwed to the housing of the worm gear transmission device, and by adjusting the screw connection preload, the compression level of the elastic member 130 between the push rod 120 and the fixing member 110 can be adjusted, thereby adjusting the force between the push rod 120 and the bearing assembled at the end of the worm, thereby improving the clearance adjustment capability of the clearance compensation mechanism 100.

[0039] In some embodiments, a cross groove 116 is disposed on the top of the nut so that the fixing member 110 is not easily slipped during the process of being screwed to the housing of the worm gear transmission device, thereby ensuring a stable screw connection.

[0040] In some embodiments, the end surface edge of the first section 120a of the push rod 120 is provided with a chamfer 123, and an oil storage cavity S is formed between the chamfer 123 and the top corner 113 of the cavity 111. The chamfer 123 facilitates the assembly of the push rod 120 into the cavity 111, and on the other hand, an oil storage cavity S can be formed between the top corner 113 of the cavity 111, and grease can be stored in the oil storage cavity S to achieve lubrication and noise reduction during the reciprocating motion of the push rod 120.

[0041] In the present embodiment, the top corner 113 of the cavity 111 is naturally formed in the process of machining the cavity 111 with an ordinary, regular tool. There is no need to separately machine an annular groove or other structures at the top corner 113, nor is there a need to use a special-shaped tool to form a groove or other structures at the top corner 113. This can simplify the tool design / process flow.

[0042] In some embodiments, the first section 120a of the push rod 120 is provided with a receiving cavity 126, and the elastic member 130 is received in the receiving cavity 126 and respectively abuts against the top wall of the cavity 111 and the bottom wall of the receiving cavity 126. When the clearance compensation mechanism 100 is used in a worm gear transmission device, the elastic member 130 is always in a compressed state so that the push rod 120 always abuts against the bearing with a suitable force. The elastic member 130 can be a coil spring or other suitable elastic elements.

[0043] The embodiment of the utility model further provides a worm gear transmission device which utilizes the above-mentioned clearance compensation mechanism 100 to adjust the clearance between the worm wheel and the worm. Figure 5 The partial structure of the worm gear transmission device in the embodiment of the utility model is shown in FIG. Figure 6 The diagram shows the matching structure of the cage and housing, the second bearing and the clearance compensation mechanism of the worm gear transmission device; Figures 1 to 6 As shown, the worm gear transmission device provided by the embodiment of the utility model includes:

[0044] A worm wheel 220 and a worm 230 are disposed in the housing 210 and meshed with each other, and both ends of the worm 230 are supported by a first bearing 241 and a second bearing 242 respectively, and the first bearing 241 is assembled with the housing 210;

[0045] The retainer 260 is sleeved at least partially outside the second bearing 242 and assembled with the housing 210. The retainer 260 limits the second bearing 242 in the first radial direction R1, and the retainer 260 is provided with a gap adjustment through hole 2600 along the second radial direction R2. The second radial direction R2 is perpendicular to the first radial direction R1 and perpendicular to the extension direction of the worm 230.

[0046] The clearance compensation mechanism 100 , wherein the fixing member 110 is assembled with the housing 210 , and the second section 120 b of the push rod 120 passes through the clearance adjustment through hole 2600 and abuts against the second bearing 242 .

[0047] The worm gear transmission device of the embodiment of the utility model utilizes the retaining frame 260 to limit the second bearing 242 in the first radial direction R1, and provides a gap adjustment through hole 2600 along the extension direction perpendicular to the worm 230, so that the gap adjustment force can be concentrated in the extension direction perpendicular to the worm 230, thereby avoiding the position displacement of the worm 230 caused by the force in other directions; the top rod 120 of the gap compensation mechanism 100 is passed through the gap adjustment through hole 2600 and abuts the second bearing 242, so as to realize the adjustment of the gap between the worm wheel 220 and the worm 230 in the extension direction perpendicular to the worm 230.

[0048] Grease may be applied between the inner ring of the retainer 260 and the outer ring of the second bearing 242 to avoid noise caused by friction between the two.

[0049] In some embodiments, the retaining frame 260 is formed as a C-shaped ring, and the two ends 260a of the C-shaped ring are in contact with the second bearing 242 to limit the second bearing 242. A gap adjustment through hole 2600 is set at the bottom of the C-shaped ring, and a gap is reserved between the bottom area 260c of the C-shaped ring and the second bearing 242.

[0050] The two ends 260a of the C-shaped ring are in contact with the second bearing 242, forming two-point contact on the first radial direction R1, thereby limiting the displacement of the second bearing 242 on the first radial direction R1; a gap is reserved between the bottom area 260c of the C-shaped ring and the second bearing 242, providing a gap adjustment space on the second radial direction R2, and reserving space for the gap adjustment movement of the push rod 120.

[0051] In some embodiments, the C-shaped ring includes a plastic frame and a rubber buffer layer disposed outside the plastic frame. The plastic frame forms the overall outline of the C-shaped ring; the rubber buffer layer is compressed and filled between the C-shaped ring and the housing 210 to keep the position of the C-shaped ring stable and achieve a buffering effect.

[0052] The present utility model also provides an electric power steering system (Electric Power Steering, EPS), which is equipped with a worm gear transmission device as described in any of the above embodiments. In an electric power steering system, a worm gear transmission device is often used to achieve deceleration and torque increase. The worm gear transmission device equipped with a clearance compensation mechanism 100 can be applied to an electric power steering system to achieve a good deceleration and torque increase effect, thereby improving the steering assistance performance of the electric power steering system.

[0053] In addition, the worm gear transmission device equipped with the clearance compensation mechanism 100 can also be applied to other scenarios requiring worm gear transmission, and can achieve stable and effective clearance adjustment between the worm wheel and the worm through the clearance compensation mechanism 100.

[0054] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A clearance compensation mechanism for a worm gear transmission, characterized in that: include: A fixing member, provided with a cavity having an opening; A push rod, wherein the first section of the push rod is reciprocatably assembled in the cavity through an elastic member and is clearance-matched with the cavity, the outer wall of the first section of the push rod is provided with a spiral groove extending from one end to the other end, and the second section of the push rod extends out of the cavity.

2. The gap compensation mechanism according to claim 1, characterized in that: The number of spiral turns of the spiral groove is between one and two.

3. The gap compensation mechanism according to claim 1, characterized in that: The fixing element is formed as a nut with external threads.

4. The gap compensation mechanism according to claim 3, characterized in that: A cross groove is arranged on the top of the nut.

5. The clearance compensation mechanism according to claim 1, characterized in that: The edge of the end surface of the first section of the push rod is provided with a chamfer, and an oil storage cavity is formed between the chamfer and the top corner of the cavity.

6. The clearance compensation mechanism according to claim 1, characterized in that: The first section of the push rod is provided with an accommodating cavity, and the elastic member is accommodated in the accommodating cavity and abuts against the top wall of the cavity and the bottom wall of the accommodating cavity respectively.

7. A worm gear transmission device, comprising a worm wheel and a worm arranged in a housing and meshing with each other, wherein two ends of the worm are supported by a first bearing and a second bearing respectively, and the first bearing is assembled with the housing; It is characterized in that The worm gear transmission device also includes: a retainer, at least sleeved outside a portion of the second bearing and assembled with the housing, the retainer limiting the second bearing in a first radial direction, and the retainer being provided with a gap adjustment through hole along a second radial direction, the second radial direction being perpendicular to the first radial direction and perpendicular to an extension direction of the worm; According to the gap compensation mechanism as described in any one of claims 1 to 5, the fixing member of the gap compensation mechanism is assembled with the housing, and the second section of the top rod of the gap compensation mechanism passes through the gap adjustment through hole and abuts against the second bearing.

8. The worm gear transmission device according to claim 7, characterized in that: The retaining frame is formed as a C-shaped ring, both ends of the C-shaped ring are in contact with the second bearing to limit the second bearing, the gap adjustment through hole is arranged at the bottom of the C-shaped ring, and a gap is reserved between the bottom area of ​​the C-shaped ring and the second bearing.

9. The worm gear transmission device according to claim 8, characterized in that: The C-shaped ring comprises a plastic frame and a rubber buffer layer arranged outside the plastic frame.

10. An electric power steering system, characterized in that: The electric power steering system is equipped with a worm gear transmission as described in any one of claims 7-9.

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