An RV reducer

Abstract

This invention relates to a speed reducer, and more particularly to an RV speed reducer; comprising: a pin tooth with a first limiting structure formed thereon; a pin tooth housing with a cylindrical space formed therein, including a cylindrical surface along the cylindrical space, and a plurality of pin tooth grooves evenly distributed along the axial direction of the cylindrical surface; a pin tooth being disposed in the pin tooth groove; a second limiting structure formed thereon on the pin tooth housing; and a limiting device that cooperates with the first limiting structure and the second limiting structure to axially limit the pin tooth, thereby solving the problem of axial sliding of the pin tooth in the RV speed reducer during operation.

Description

Technical Field

[0001] This invention relates to a speed reducer, and more particularly to an RV speed reducer. Background Technology

[0002] RV reducers are one of the core components of robot transmission. RV reducers have advantages such as large reduction ratio, coaxial transmission, high transmission accuracy, high rigidity, and compact structure. However, in existing RV reducers, there is a certain gap between the two ends of the pin tooth and the bearing. Due to changes in force during operation, the pin tooth is subjected to uneven force, which can easily lead to axial slippage. This axial slippage exacerbates the uneven force on the pin tooth and also squeezes the bearing, generating vibration and noise. This directly affects the working accuracy of the RV reducer and, consequently, reduces the working accuracy of the robot.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] To address the issue of axial slippage of the pin teeth in an RV reducer during operation, this invention proposes an RV reducer comprising:

[0005] A pin toothed pin, on which a first limiting structure is formed;

[0006] A needle-tooth shell has a cylindrical space formed inside it, and a cylindrical surface is included along the cylindrical space. Multiple needle-tooth grooves are evenly distributed on the cylindrical surface along the axial direction of the cylindrical surface. The needle-tooth pin is disposed in the needle-tooth groove. A second limiting structure is formed on the needle-tooth shell.

[0007] A limiting device, which cooperates with the first limiting structure and the second limiting structure to axially limit the pin.

[0008] Preferably, a first annular groove is formed on the outer peripheral surface of the pin, the first annular groove extending circumferentially along the outer peripheral surface of the pin, and the first limiting structure includes the first annular groove;

[0009] The limiting device includes a limiting ring plate, the inner side of which has notches corresponding to the pin teeth, and the outer side of which has a third limiting structure that matches the second limiting structure.

[0010] The limiting ring plate is fixed to the needle tooth shell by the third limiting structure and the second limiting structure, the needle tooth pin is engaged at the notch by the first ring groove, and the needle tooth pin can rotate around its own axis.

[0011] Preferably, a second annular groove is formed on the cylindrical surface of the pin gear housing, and the second annular groove extends along the circumferential direction of the cylindrical surface;

[0012] The limiting ring plate is clamped in the second annular groove, and the limiting ring plate is in clearance fit with the second annular groove; the gaps on the limiting ring plate correspond to the pin tooth pin grooves one by one; when the pin tooth pins are arranged in the pin tooth pin grooves, a part of the limiting ring plate at the gap is clamped into the first annular groove.

[0013] Preferably, the limiting ring plate includes a first ring plate and a second ring plate, and the first ring plate and the second ring plate are connected end to end to form a ring.

[0014] Preferably, the gaps are arc-shaped, the sizes of the gaps on the first ring plate are all the same, and the sizes of the gaps on the second ring plate are all the same.

[0015] Preferably, the central angle corresponding to the first ring plate is α, α = m * 180 / (2 * (r2 - r1) * π) < α < m * 180 / ((r2 - r1) * π), r1 is the inner hole radius of the first ring plate, r2 is the outer peripheral radius of the first ring plate, and m is the inner arc length of the pin tooth pin groove;

[0016] The central angle corresponding to the second ring plate is β, β = 360° - α.

[0017] Preferably, axial first through holes A are formed at both ends of the first ring plate, axial second through holes A are formed at both ends of the second ring plate, axial first through holes B matching the first through holes are formed on the pin gear housing, and axial second through holes B matching the second through holes A are formed on the pin gear housing;

[0018] The first ring plate can be clamped into the second annular groove to make the first through hole A correspond to the first through hole B. When the first through hole A corresponds to the first through hole B, a pin is inserted into the first through hole A and the first through hole B to fix the first ring plate;

[0019] The second ring plate can be clamped into the second annular groove to make the second through hole A correspond to the second through hole B. When the second through hole A corresponds to the second through hole B, a pin is inserted into the second through hole A and the second through hole B to fix the second ring plate;

[0020] When the first ring plate and the second ring plate are both fixed in the second annular groove, the first ring plate and the second ring plate form a ring.

[0021] Preferably, the outer ring surface of the first ring plate is formed with a first groove that axially penetrates the first ring plate, and the outer ring surface of the second ring plate is formed with a second groove that axially penetrates the second ring plate.

[0022] Preferably, a first threaded hole is formed on one end face of the pin, and a second threaded hole is formed on one end face of the pin.

[0023] Preferably, the RV reducer further includes bearing mounting positions disposed at both ends of the cylindrical space, each bearing mounting position being provided with a bearing, the bearing being coaxial with the cylindrical space;

[0024] The pin is located between the two bearings, and there is a gap between each end of the pin and the bearing.

[0025] Preferably, the RV reducer further includes two cycloidal wheels, which are respectively disposed on both sides of the limiting device in the axial direction of the cylindrical space.

[0026] This invention provides a first annular groove on the pin tooth and a second annular groove on the pin tooth housing. By using a limiting ring plate to axially limit the pin tooth, it prevents the pin tooth from sliding axially. At the same time, the limiting ring plate separates the two cycloidal wheels on both sides of the axial direction, preventing interference between the wheels. This improves the uniformity of force on the pin tooth, reduces the operating noise and vibration of the RV reducer, and improves the operating accuracy and lifespan of the RV reducer. Attached Figure Description

[0027] Figure 1 This is an exploded view of the RV reducer according to an embodiment of the present invention;

[0028] Figure 2 This is a front sectional view of the RV reducer according to an embodiment of the present invention;

[0029] Figure 3 This is an external view of the RV reducer according to an embodiment of the present invention;

[0030] Figure 4 This is a front view of the pin tooth pin according to an embodiment of the present invention;

[0031] Figure 5 This is a front view of the first annular plate according to an embodiment of the present invention;

[0032] Figure 6 This is a left view of the first annular plate in an embodiment of the present invention;

[0033] Figure 7 This is an embodiment of the present invention. Figure 5 Enlarged view at point C;

[0034] Figure 8 This is a front view of the second ring plate according to an embodiment of the present invention;

[0035] Figure 9 This is a left view of the second annular plate in an embodiment of the present invention;

[0036] Figure 10 This is an embodiment of the present invention. Figure 8 Enlarged view at point D;

[0037] Figure 11 This is a schematic diagram of the limiting ring plate formed by the first ring plate and the second ring plate in an embodiment of the present invention;

[0038] Figure 12 This is a front view of the pin in an embodiment of the present invention;

[0039] Figure 13 This is a top view of the pin in an embodiment of the present invention;

[0040] Figure 14 This is a front view of the needle-tooth shell according to an embodiment of the present invention;

[0041] Figure 15 This is a front sectional view of the pin tooth shell according to an embodiment of the present invention;

[0042] Figure 16 This is a top view of the needle-tooth shell according to an embodiment of the present invention.

[0043] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0044] In the attached drawings: 1-pin tooth; 2-pin tooth housing; 201-pin tooth groove; 101-first annular groove; 3-notch; 202-second annular groove; 4-first annular plate; 5-second annular plate; 401-first through hole A; 402-first through hole B; 501-second through hole A; 502-second through hole B; 403-first groove; 503-second groove; 6-pin; 601-threaded hole; 7-bearing; 8-cycloidal wheel. Detailed Implementation

[0045] 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 of the present invention. 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.

[0046] 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. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0047] This invention relates to a speed reducer, and more particularly to an RV speed reducer. The RV speed reducer is one of the core components of robot transmission. RV speed reducers have advantages such as large reduction ratio, coaxial transmission, high transmission accuracy, high rigidity, and compact structure. In existing RV speed reducers, there is a certain gap between the two ends of the pin tooth and the bearing. Due to changes in force during operation, the pin tooth is subjected to uneven force, which easily leads to axial sliding. This axial sliding of the pin tooth exacerbates the uneven force on the pin tooth and also squeezes the bearing, generating vibration and noise. This severely affects the working accuracy of the RV speed reducer, and thus reduces the working accuracy of the robot.

[0048] In response to the above problems, such as Figure 1-16 As shown, the present invention proposes an RV reducer, comprising: a pin 1 with a first limiting structure formed on the pin 1; a pin housing 2 with a cylindrical space formed inside the pin housing 2, including a cylindrical surface along the cylindrical space, and a plurality of pin 1 grooves evenly distributed along the axial direction of the cylindrical surface; the pin 1 being disposed in the pin 1 groove; a second limiting structure formed on the pin housing 2; and a limiting device that cooperates with the first limiting structure and the second limiting structure to axially limit the pin 1; by limiting the pin 1 in its own axial direction through the limiting device, the pin 1 is restricted from sliding in the axial direction during the operation of the RV reducer.

[0049] Preferred, such as Figure 4 As shown, a first annular groove 101 is formed on the outer peripheral surface of the pin 1. The first annular groove 101 extends circumferentially along the outer peripheral surface of the pin 1, and the first limiting structure includes the first annular groove 101; as shown Figure 5-11As shown, the limiting device includes a limiting ring plate. The inner side of the limiting ring plate has notches 3 corresponding to the pin teeth 1, and the outer side of the limiting ring plate has a third limiting structure matching the second limiting structure. The limiting ring plate is fixed to the pin tooth shell 2 via the third and second limiting structures. The pin teeth 1 are engaged at the notches 3 via the first annular groove 101, allowing the pin teeth 1 to rotate around its own axis. The limiting plate is fixed to the pin tooth shell 2, and the pin teeth 1 are engaged at the notches 3 via the first annular groove 101. That is, the limiting ring plate at the notches 3 is engaged in the first annular groove 101, limiting the pin teeth 1 in the axial direction and preventing it from sliding in the axial direction. The limiting ring plate and the first annular groove 101 are in clearance fit, allowing the pin teeth 1 to rotate around its own axis.

[0050] Preferred, such as Figure 15 As shown, a second annular groove 202 is formed on the cylindrical surface of the pin tooth shell 2, and the second annular groove 202 extends circumferentially along the cylindrical surface; a limiting ring plate is engaged in the second annular groove 202, and the limiting ring plate and the second annular groove 202 are in clearance fit; the notch 3 on the limiting ring plate corresponds one-to-one with the groove of the pin tooth pin 1; when the pin tooth pin 1 is set in the groove of the pin tooth pin 1, part of the limiting ring plate at the notch 3 is engaged in the first annular groove 101; the limiting ring plate includes a first annular plate 4 and a second annular plate 5, as shown in the figure. Figure 11 As shown, the first ring plate 4 and the second ring plate 5 can be connected end to end to form a ring; the limiting ring plate is designed as the first ring plate 4 and the second ring plate 5 for easy installation, as shown. Figure 7 As shown, the outer ring surface of the first ring plate 4 is formed with a first groove 403 that axially penetrates the first ring plate 4, such as... Figure 10As shown, axial second grooves 503 penetrating the second ring plate 5 are formed on the outer circumferential surfaces of the second ring plate 5; the notch 3 is arc-shaped, and the sizes of the notches 3 on the first ring plate 4 are all the same, and the sizes of the notches 3 on the second ring plate 5 are all the same; by making the sizes of the notches 3 the same, in the axial direction, the acting forces of the first ring plate 4 and the second ring plate 5 on the pin tooth pin 1 are the same, and at the same time, it is also avoided that there are notches 3 at the joints of the first ring plate 4 and the second ring plate 5, that is, the notches 3 on the first ring plate 4 and the second ring plate 5 are the same and complete notches 3; the radius of the arc-shaped notch 3 is slightly larger than the radius of the bottom of the first ring groove 101. When the pin tooth pin 1 rotates, there is no friction or very little friction between the pin tooth pin 1 and the notch 3 in the radial direction, and at the same time, lubricating oil can be stored between the notch 3 and the first ring groove 101; before installing the first ring plate 4 and the second ring plate 5, lubricating oil is first injected into the second ring groove 202. When the first ring plate 4 and the second ring plate 5 are installed, the lubricating oil is extruded, and the lubricating oil can flow to the outer cylindrical surface of the pin tooth pin 1 and into the first ring groove 101. At the same time, the first groove 403 and the second groove 503 between the limiting ring plate and the second ring groove 202 can store lubricating oil, forming segmented lubrication, namely the second ring groove 202 and both sides of the second ring groove 202. The segmented lubrication increases the contact area between the lubricating oil and the pin tooth pin 1, which is beneficial to accelerating the cooling of the pin tooth pin 1 and the cycloid gear 8; effectively avoiding the aggravation of wear caused by too high temperatures of the pin tooth pin 1 and the cycloid gear 8, and even causing the pin tooth pin 1 to be deformed by external forces at high temperatures; the first ring plate 4 and the second ring plate 5 can be made of spring steel material.

[0051] Preferably, as Figure 5 and Figure 8 shown, the central angle corresponding to the first ring plate 4 is α, α = m * 180 / (2 * (r2 - r1) * π) < α < m * 180 / ((r2 - r1) * π), r1 is the inner hole radius of the first ring plate 4, r2 is the outer peripheral radius of the first ring plate 4, and m is the inner arc length of the pin tooth groove of the pin tooth pin 1; the central angle corresponding to the second ring plate 5 is β, β = 360° - α; the central angle of the first ring plate 4 is related to the arc length of the inner circle of the pin tooth hole, the outer diameter of the first ring plate 4, and the inner diameter of the first ring plate 4. According to the formula of the first ring plate 4, the central angle of the first ring plate 4 can be determined without considering the specific size of the pin tooth housing 2, which has high universality.

[0052] Preferably, as Figure 7 and Figure 10 shown, axial first through holes A401 are opened at both ends of the first ring plate 4, and axial second through holes A501 are opened at both ends of the second ring plate 5, as Figure 16As shown, the needle-tooth shell 2 has an axially oriented first through hole B402 that matches the first through hole, and an axially oriented second through hole B502 that matches the second through hole A501. The first ring plate 4 can be inserted into the second ring groove 202 so that the first through hole A401 corresponds to the first through hole B402. When the first through hole A401 corresponds to the first through hole B402, a pin 6 is inserted into the first through hole A401 and the first through hole B402 to fix the first ring plate 4. The second ring plate 5 can be inserted into the second ring groove 202 so that the second through hole A501 corresponds to the second through hole B502. When the second through hole A501 corresponds to the second through hole B502, the second through hole A501... A pin 6 is inserted into the second through hole B502 to fix the second ring plate 5. When both the first ring plate 4 and the second ring plate 5 are fixed in the second ring groove 202, the first ring plate 4 and the second ring plate 5 form a ring. A first threaded hole 601 is opened on one end face of the pin 6, and a second threaded hole 601 is opened on the other end face of the pin 6. The first ring plate 4 is inserted into the second ring groove 202 and the first through hole A401 is aligned with the first through hole B402. A screw is installed in the threaded hole 601 of the pin 6. The pin 6 is installed in the first through hole A401 and the first through hole B402 by the screw, thereby positioning and fixing the first ring plate 4. The second ring plate 5 is limited and fixed in the same way.

[0053] Preferred, such as Figure 2 As shown, the RV reducer also includes bearing 7 mounting positions at both ends of the cylindrical space, with one bearing 7 mounted at each bearing 7 mounting position. The bearing 7 is coaxial with the cylindrical space. The pin 1 is located between the two bearings 7, and there is a gap between either end of the pin 1 and the bearing 7. When the pin 1 rotates around its own axis, both ends of the pin 1 maintain a gap with the bearing 7 to avoid interference between the pin 1 and the bearing 7.

[0054] Preferred, such as Figure 2 As shown, the RV reducer also includes two cycloidal wheels 8, which are respectively arranged on both sides of the limiting device in the axial direction of the cylindrical space. The two cycloidal wheels 8 are respectively installed on both sides of the limiting device, that is, on both sides of the limiting ring plate formed by the first ring plate 4 and the second ring plate 5. In this way, the collision and friction between the two cycloidal wheels 8 are effectively avoided.

[0055] During the installation of the limiting device, lubricating oil is injected into the second annular groove 202. The outer circle of the first annular plate 4 is inserted into the second annular groove 202, so that the first through hole A401 is aligned with the first through hole B402. The screw is installed in the threaded hole 601 on the pin 6. The brass drum screw is used to install the pin 6 in the first through hole A401 and the first through hole B402, thereby radially positioning and fixing the first annular plate 4. The second annular plate 5 is installed in the same way. After the limiting device is installed, other components are installed.

[0056] When the RV reducer is assembled and in use, the two cycloidal wheels 8 rotate around their own axes while simultaneously rotating around the axis of the RV reducer. The outer teeth of the cycloidal wheels 8 engage and disengage with the pin 1. The lubricating oil in the second annular groove 202 flows out and enters the first annular groove 101 to lubricate the first annular groove 101 and the pin 1, reducing the radial force between the pin 1 and the first annular plate 4 and the second annular plate 5; at the same time, it cools the pin 1. When the external force is uneven or unstable, the external force is transmitted to the pin 1 through the cycloidal wheels 8, causing unbalanced compression of the pin 1. This compression force causes the pin 1 to be subjected to axial stress. Under the action of axial force, the pin 1 slides relative to the pin housing 2. The sliding distance here is extremely small, only the axial gap between the first annular groove 101 and the limiting ring plate. At this time, the sliding of the pin 1 will not impact the bearings 7 at both ends, and there will be no abnormal vibration or noise. After the pin 1 slides axially to eliminate the axial gap between the limiting ring plate and the first annular groove 101, the pin 1 axially compresses the limiting ring plate. Since the limiting ring plate is fixed on the pin housing 2, the limiting ring plate will not slide under the compression of the pin 1. Correspondingly, the limiting ring prevents the pin 1 from sliding axially.

[0057] The present invention has the following significant advantages:

[0058] 1. This invention provides a first annular groove on the pin tooth and a limiting ring plate between the two cycloidal wheels. The pin tooth is engaged in the first annular groove through a notch in the limiting ring plate, thereby limiting the pin tooth in the axial direction and preventing it from sliding. This prevents the pin tooth from squeezing the bearings at both ends and prevents the pin tooth from sliding axially due to uneven force, which would exacerbate the uneven force phenomenon. This effectively improves the operational stability and accuracy of the RV reducer and effectively reduces abnormal noise and vibration. At the same time, the limiting ring plate between the two cycloidal wheels prevents friction and interference between them.

[0059] 2. By setting a second annular groove inside the pin housing, the limiting ring plate is fixed by being inserted into the second annular groove. At the same time, a segmented lubrication structure is formed between the limiting ring plate and the second annular groove. The segmented lubrication structure stores lubricating oil, and the lubricating oil flows out to lubricate the pin and the limiting ring plate, as well as the pin and the cycloidal wheel, thereby improving the rotational accuracy of the cycloidal wheel. The lubricating oil also has a cooling effect on the friction parts and the pin, improving the stability of RV operation and extending the service life of the RV reducer.

[0060] Exemplary embodiments of this disclosure have been specifically shown and described above. It should be understood that this disclosure is not limited to the detailed structures, arrangements, or implementations described herein; rather, this disclosure is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. An RV reducer, characterized in that, Comprising: A pin tooth pin, on which a first limiting structure is formed; A pin tooth housing, within which a cylindrical space is formed. Along the cylindrical space, there is a cylindrical surface, and a plurality of pin tooth pin slots are evenly distributed along the axial direction of the cylindrical surface on the cylindrical surface; the pin tooth pins are arranged in the pin tooth pin slots; a second limiting structure is formed on the pin tooth housing; A limiting device, which cooperates with the first limiting structure and the second limiting structure respectively to axially limit the pin tooth pins; A first annular groove is formed on the outer peripheral surface of the pin tooth pin, and the first annular groove extends along the circumferential direction of the outer peripheral surface of the pin tooth pin. The first limiting structure includes the first annular groove; The limiting device includes a limiting ring plate, on the inner side of which there are gaps corresponding to the pin tooth pins one by one, and on the outer side of which there is a third limiting structure matching the second limiting structure; The limiting ring plate is fixed on the pin tooth housing through the third limiting structure and the second limiting structure. The pin tooth pin is clamped at the gap through the first annular groove, and the pin tooth pin can rotate around its own axis.

2. The RV reducer according to claim 1, characterized in that, A second annular groove is formed on the cylindrical surface of the pin tooth housing, and the second annular groove extends along the circumferential direction of the cylindrical surface; The limiting ring plate is clamped in the second annular groove, and the limiting ring plate has a clearance fit with the second annular groove; the gaps on the limiting ring plate correspond to the pin tooth pin slots one by one; when the pin tooth pin is arranged in the pin tooth pin slot, a part of the limiting ring plate at the gap is clamped into the first annular groove.

3. An RV reducer according to claim 2, characterized in that, The limiting ring plate includes a first ring plate and a second ring plate, and the first ring plate and the second ring plate are connected end to end to form a ring.

4. An RV reducer according to claim 3, characterized in that, The gaps are arc-shaped, the sizes of the gaps on the first ring plate are all the same, and the sizes of the gaps on the second ring plate are all the same.

5. An RV reducer according to claim 3, characterized in that, The central angle corresponding to the first ring plate is α, α = m * 180 / (2 * (r2 - r1) * π) < α < m * 180 / ((r2 - r1) * π), r1 is the inner hole radius of the first ring plate, r2 is the outer peripheral radius of the first ring plate, and m is the inner arc length of the pin tooth pin slot; The central angle corresponding to the second ring plate is β, β = 360° - α.

6. An RV reducer according to claim 5, characterized in that, Axial first through holes A are opened at both ends of the first ring plate, axial second through holes A are opened at both ends of the second ring plate, axial first through holes B matching the first through holes are opened on the pin tooth housing, and axial second through holes B matching the second through holes A are opened on the pin tooth housing; The first ring plate can be clamped into the second annular groove to make the first through hole A correspond to the first through hole B. When the first through hole A corresponds to the first through hole B, a pin is inserted into the first through hole A and the first through hole B to fix the first ring plate; The second ring plate can be clamped into the second annular groove to make the second through hole A correspond to the second through hole B. When the second through hole A corresponds to the second through hole B, a pin is inserted into the second through hole A and the second through hole B to fix the second ring plate; When both the first ring plate and the second ring plate are fixed in the second ring groove, the first ring plate and the second ring plate form a ring shape.

7. An RV reducer according to claim 6, characterized in that, The outer ring surface of the first ring plate has a first groove that axially penetrates the first ring plate, and the outer ring surface of the second ring plate has a second groove that axially penetrates the second ring plate.

8. An RV reducer according to claim 7, characterized in that, The pin has a first threaded hole on one end face and a second threaded hole on the other end face.

9. An RV reducer according to claim 8, characterized in that, The RV reducer also includes bearing mounting positions at both ends of the cylindrical space, each bearing mounting position having a bearing coaxial with the cylindrical space. The pin is located between the two bearings, and there is a gap between each end of the pin and the bearing.

10. An RV reducer according to any one of claims 1-9, characterized in that, The RV reducer also includes two cycloidal wheels, which are respectively disposed on both sides of the limiting device in the axial direction of the cylindrical space.

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