A super-strong load cylindrical pin type shift fork drive mechanism

Abstract

A super-load cylindrical pin type shift fork drive mechanism belongs to the technical field of fluid or gas pressure actuators, and solves the technical problems of reducing the piston moving distance of the shift fork type drive head and improving the output torque. The solution is: a shift fork step surface is set on the side wall of the piston rod, a step groove is set in the middle of the shift fork step surface, and two cylindrical pins are arranged in parallel at the opening position of the step groove; the shift fork includes a cylindrical base, a transition connection part and a shift block, the shift fork is an axisymmetric structure, and the root of the shift block is fixedly connected to the base through the transition connection part, and the motion trajectory of the cylindrical pin and the inner wall of the left and right sides of the linear slide when the piston rod drives the cylindrical pin to move in the prior art is used as the contour surface of the shift block. The present invention replaces the transmission structure of the cylindrical pin and the inner wall of the linear slide in the prior art by matching the outer contour surface of the cylindrical pin and the shift block, and the overall length of the shift fork drive head is reduced by half, and the torque range is increased by more than 6 times compared with the traditional one.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid or gas pressure actuators, relates to valve actuators, and specifically to an ultra-high load cylindrical pin type shift fork driving mechanism. Background Art

[0002] For large pneumatic or hydraulic actuators with torque requirements higher than 7000Nm, rack and pinion actuators are often not cost-effective because the cost of large-module gear processing machine tools is very high. For gear modules greater than 6, the processing cost increases by 1 times, and for modules greater than 12, the cost increases exponentially. In addition, the mass of the rack and pinion itself is very heavy, so the rack and pinion drive head is not only uneconomical, but also bulky and heavy, and its own starting load is relatively high. Therefore, the cylindrical pin-fork transmission structure is widely used in pneumatic drive heads or hydraulic drive heads, especially the control actuators for opening and closing large-caliber valves. The fork structure has the advantages of simple structure and low processing cost. There are two main fork structures commonly used in the prior art, namely:

[0003] 1. Patent application WO2017060758A1 discloses a spring-reset double piston rod stop yoke actuator. Currently, more than 90% of mainstream manufacturers use this structure. As shown in the accompanying drawings of the patent application, the cylindrical pin is fixed on the piston rod. The fork of the transmission structure is as shown in FIG. Figure 1 As shown, when the piston rod drives the cylindrical pin to move rightward, the trajectory of the cylindrical pin and the right inner wall of the linear slideway in cooperation is AA`, and when the piston rod drives the cylindrical pin to move leftward, the trajectory of the cylindrical pin and the left inner wall of the linear slideway in cooperation is BB`;

[0004] 2. Patent application EP3048350A1 discloses a butterfly valve with an improved stop valve yoke connection, as shown in the accompanying drawings of the specification of the patent application, in which a cylindrical pin is fixed on a shift fork.

[0005] like Figure 2 As shown, the working principle of the above two forms of fork structures is: under the action of hydraulic oil or compressed air, the piston makes reciprocating linear motion, and then drives the fork through the cylindrical pin to generate output torque, and the fork drives the valve stem to rotate in the clockwise or counterclockwise direction to realize the opening and closing of the valve.

[0006] In summary, the common point of the above two forms of fork structures is that the linear motion of the piston is converted into the rotational motion of the fork by sliding the cylindrical pin in the linear groove. However, the main disadvantage of the fork structure is that it is large in size. The overall length of the fork cylinder is twice that of the gear rack structure, and the weight is more than 1.4 times that of the gear rack structure. Therefore, how to have the cost advantages of the simple structure and cheap processing of the fork, while significantly reducing the overall volume, weight and cost, has become a technical problem that needs to be solved urgently. Summary of the invention

[0007] In order to overcome the deficiencies of the prior art and solve the technical problems of reducing the piston movement distance of the fork-type drive head and increasing the maximum allowable output torque, the present invention provides an ultra-high load cylindrical pin-type fork drive mechanism.

[0008] To achieve the above object, the present invention is implemented according to the following technical solution: an ultra-strong load cylindrical pin type fork drive mechanism, which includes a piston rod, a fork and a cylindrical pin, wherein:

[0009] The piston rod is arranged in the horizontal direction, a shift fork step surface is arranged on the side wall of the piston rod, a step groove is arranged in the middle of the shift fork step surface, and the length direction of the step groove is perpendicular to the axial direction of the piston rod; the two cylindrical pins are arranged in parallel at the opening position of the step groove, and the section where the side wall of the step groove is located intersects with the outer cylindrical surface of the corresponding side cylindrical pin;

[0010] The shift fork is an axisymmetric structure, the shift fork comprises a cylindrical base, a transition connection part and a shift block, the transition connection part is fixedly arranged on the outer cylindrical surface of the base, the outer cylindrical surface of the root of the transition connection part is tangent to the outer cylindrical surface of the base, the outer cylindrical surface of the transition connection part is a 1 / 4 cylindrical surface, and the arc radius of the 1 / 4 cylindrical surface is equal to the radius of the cylindrical pin; the root of the shift block is fixedly connected to the transition connection part, the arc length of the root of the shift block is equal to 1 / 2 of the spacing between the two cylindrical pins, and the free end of the shift block reciprocates in the give way groove. According to the existing transmission structure of the shift fork and cylindrical pin, the motion trajectory of the cylindrical pin and the right inner wall of the linear slide when the piston rod drives the cylindrical pin to move to the right is used as the left side wall contour surface of the shift block, and the motion trajectory of the cylindrical pin and the left inner wall of the linear slide when the piston rod drives the cylindrical pin to move to the left is used as the right side wall contour surface of the shift block. The left side wall contour surface is symmetrical with the right side wall contour surface. The shift fork moves along the linear slide groove arranged on the shift fork, that is, the shift fork and the cylindrical pin are in line contact transmission, the minimum transmission gap is 0.2~0.5mm, and the transmission gap will become larger and larger with use and wear; in the present invention, the cylindrical pin slides or rolls along the contour line of the outer wall of the shift block and the semicircular groove, the shift fork and the cylindrical pin are in a combined transmission form of line contact transmission and surface contact transmission, the minimum transmission gap can reach 0.01mm, zero gap transmission can be achieved, the service life is extended, and maintenance-free for life during service; the outer cylindrical surfaces of the two cylindrical pins are simultaneously matched with the left wall contour surface and the right wall contour surface of the shift block for transmission, and in the process of the matching transmission between the shift block and the cylindrical pin, at least one cylindrical pin is always matched with the outer cylindrical surface of the transition connection part, the piston rod drives the shift block to swing forward or reversely through the cylindrical pin to output torque, and then drives the valve stem to rotate clockwise or counterclockwise through the shift fork to realize the opening or closing of the valve.

[0011] Furthermore, the rotation angle between the shift fork and the valve is 90 degrees ± 10 degrees.

[0012] Furthermore, a bearing is installed on the cylindrical pin at a position matching with the shift block.

[0013] Furthermore, the bearing is a heavy-duty needle roller bearing or an oil film bearing.

[0014] Furthermore, the free end of the left side wall contour surface and the free end of the right side wall contour surface are transitionally connected via an involute arc surface.

[0015] Furthermore, wing plates are symmetrically arranged on the outer circular surface of the base and on the left and right sides of the shift block. The length of the wing plates is smaller than the length of the shift block. The inner circular surface of the wing plates and the outer circular surface of the transition connection part form a semi-cylindrical groove. When the piston rod moves horizontally to the left and right extreme positions, the outer circular surface of the wing plates contacts the step surface.

[0016] Furthermore, the base, transition connection portion, shift block and wing plate are integrally formed.

[0017] Furthermore, the rotation angle between the shift fork and the valve is 120 degrees ± 5 degrees, and the valve has a self-locking function at the extreme rotation position.

[0018] Furthermore, the thickness of the shift block is not greater than the length of the cylindrical pin.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The cylindrical pin type shift fork drive mechanism provided by the present invention replaces the transmission structure in the prior art in which the cylindrical pin cooperates with the inner wall of the linear slide groove by matching the outer contour surface of the cylindrical pin and the shift block. The overall length of the shift fork drive head is reduced by half, and the weight is reduced by more than 30% compared with the traditional shift fork drive head, and more than 40% compared with the gear rack structure; the product cost can be saved by 30% to 50% compared with the traditional shift fork drive head;

[0021] 2. The cylindrical pin type shift fork drive mechanism provided by the present invention doubles the maximum allowable torque: the number of cylindrical pins increases from one to two, and the size of the cylindrical pins is more than four times the module of the traditional gear. Therefore, the transmittable torque capacity increases exponentially, and the maximum allowable output torque can be increased by more than four times compared with the traditional shift fork structure; the maximum allowable output torque is increased by more than eight times compared with the gear rack structure drive head;

[0022] 3. The cylindrical pin type shift fork driving mechanism provided by the present invention can realize zero-gap transmission: by adjusting the extension length of the shift block, the two cylindrical pins cooperate with the left wall contour surface and the right wall contour surface of the shift block at the same time to realize zero-gap transmission in the positive and reverse directions, which is an advantage that the traditional gear rack method and the shift fork structure cannot have;

[0023] 4. The cylindrical pin type shift fork driving mechanism provided by the present invention changes the linear sliding of the shift fork and the cylindrical pin in the traditional shift fork structure into sliding and rolling with large arc contact area, so the contour wear of the cylindrical pin and the shift fork is extremely small. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the front view of the assembly structure of the pull fork and the cylindrical pin in the prior art;

[0025] Figure 2 This is the working principle diagram of the shift fork structure;

[0026] Figure 3 This is a schematic diagram of the three-dimensional structure of the assembly of the fork and the cylindrical pin in Example 1;

[0027] Figure 4 It is a partial cross-sectional three-dimensional structural schematic diagram of the cylindrical pin type fork driving mechanism in Example 1 in working state;

[0028] Figure 5 This is a schematic diagram of the top view of the assembly structure of the fork and the cylindrical pin in Example 1;

[0029] Figure 6 This is a schematic diagram of the top view of the fork structure in Example 1;

[0030] Figure 7 This is a schematic diagram of the motion state of the fork and cylindrical pin assembly structure in Example 1; wherein: Figure 7 a) The piston rod is at the left limit position. Figure 7 b) The piston rod is in the middle position. Figure 7 c) The piston rod is in the right limit position;

[0031] Figure 8 This is a schematic diagram of the top view of the assembly structure of the fork and the cylindrical pin in Example 2;

[0032] Fig. 9 This is a schematic diagram of the top view of the fork structure in Example 2;

[0033] Fig.10 It is a schematic diagram of the motion state of the fork and cylindrical pin assembly structure in Example 2; wherein, Fig.10 a) The piston rod is in the right limit position (the rotation angle between the fork and the valve is -15°). Fig.10b) The piston rod is in the right starting position in the working state (the rotation angle between the fork and the valve is 0°). Fig.10 c) The piston rod is in the middle starting position of the working state (the rotation angle between the fork and the valve is 45°). Fig.10 d) The piston rod is in the left starting position in the working state (the rotation angle between the fork and the valve is 90°). Fig.10 e) The piston rod is in the left extreme position (the rotation angle between the fork and the valve is 105°).

[0034] In the figure, 1 is the piston rod, 1-1 is the shift fork step surface, 1-2 is the shift groove, 2 is the cylindrical pin, 3 is the shift fork, 3-1 is the base, 3-2 is the transition connection part, 3-3 is the shift block, 3-4 is the semicircular groove, 3-5 is the left wall contour surface, 3-6 is the right wall contour surface, 3-7 is the wing plate, and 4 is the linear slide groove. DETAILED DESCRIPTION

[0035] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Unless otherwise specified, the examples are all based on conventional experimental conditions. In addition, for those skilled in the art, without departing from the essence and scope of the present invention, various modifications or improvements to the material components and dosages in these embodiments are within the scope of the present invention. Example

[0036] In this embodiment 1, the preset angle of valve rotation is 90°.

[0037] like Figures 3 to 7 The illustrated embodiment is a super-load cylindrical pin type shift fork driving mechanism, which comprises a piston rod 1, a shift fork 3 and a cylindrical pin 2, wherein:

[0038] The piston rod 1 is arranged in the horizontal direction, the diameter of the piston rod 1 is 100mm, the length of the piston rod 1 is 354mm, a shift fork step surface 1-1 is arranged on the side wall of the piston rod 1, a shift fork step surface 1-1 is arranged in the middle of the shift fork step surface 1-1, and the length direction of the shift fork slot 1-2 is perpendicular to the axial direction of the piston rod 1; two cylindrical pins 2 are arranged in parallel at the opening position of the shift fork slot 1-2, the diameter of the cylindrical pin 2 is 36.128mm, the length of the cylindrical pin 2 is 80mm, and the section where the side wall of the shift fork slot 1-2 is located intersects with the outer cylindrical surface of the corresponding side cylindrical pin 2;

[0039] The shift fork 3 is an axisymmetric structure. The shift fork 3 includes a cylindrical base 3-1, a transition connection part 3-2 and a shift block 3-3. The transition connection part 3-2 is fixedly arranged on the outer cylindrical surface of the base 3-1. The outer cylindrical surface of the root of the transition connection part 3-2 is tangent to the outer cylindrical surface of the base 3-1. The outer cylindrical surface of the transition connection part 3-2 is a 1 / 4 cylindrical surface, and the arc radius of the 1 / 4 cylindrical surface is equal to the radius of the cylindrical pin 2; the root of the shift block 3-3 is fixedly connected to the transition connection part 3-2, and the arc length of the root of the shift block 3-3 is equal to 1 / 2 of the spacing between the two cylindrical pins 2 (72.256mm). The free end of the shift block 3-3 reciprocates in the give way groove 1-2. According to the existing shift fork and cylindrical pin transmission structure, when the piston rod 1 drives the cylindrical pin 2 to move right, the motion trajectory of the cylindrical pin 2 cooperating with the right inner wall of the linear slide groove 4 is used as the shift block 3-3. The left side wall contour surface 3-5, when the piston rod 1 drives the cylindrical pin 2 to move left, the motion trajectory of the cylindrical pin 2 cooperating with the left inner wall of the linear slide 4 is used as the right side wall contour surface 3-6 of the shift block 3-3, and the left side wall contour surface 3-5 and the right side wall contour surface 3-6 are symmetrically arranged; the outer cylindrical surfaces of the two cylindrical pins 2 are simultaneously coordinated with the left side wall contour surface 3-5 and the right side wall contour surface 3-6 of the shift block 3-3 for transmission, and the matching accuracy is 0.01mm~0.2mm, and in the process of the coordinated transmission between the shift block 3-3 and the cylindrical pin 2, at least one cylindrical pin 2 is always kept in coordination with the outer cylindrical surface of the transition connection part 3-2, the thickness of the shift block 3-3 is not greater than the length of the cylindrical pin 2, the piston rod 1 drives the shift block 3-3 to swing forward or reversely through the cylindrical pin 2 to output torque, and then drives the valve stem to rotate clockwise or counterclockwise through the shift fork 3 to realize the opening or closing of the valve.

[0040] Furthermore, in order to further reduce the friction between the contact surface of the cylindrical pin 2 and the shift block 3 - 3 , a bearing can be installed on the cylindrical pin 2 at the position where it cooperates with the shift block 3 - 3 , and the bearing can be a heavy needle roller bearing or an oil film bearing. Example 2

[0041] The preset angle of valve rotation in this embodiment 2 is 120 degrees.

[0042] like Figures 8 to 10 The embodiment 2 is different from the embodiment 1 in the following two aspects:

[0043] First, in the first embodiment, the free ends of the left wall contour surface 3-5 and the right wall contour surface 3-6 of the shift fork 3 intersect, and in the second embodiment, the free ends of the left wall contour surface 3-5 and the right wall contour surface 3-6 are transitionally connected by an involute arc surface, and the transmission similar to that of the first embodiment can be achieved even when the extension length is shortened;

[0044] Second, the structure of the shift fork 3 in the second embodiment is based on that in the first embodiment, wing plates 3-7 are symmetrically arranged on the outer circumferential surface of the base body 3-1 and on the left and right sides of the shift block 3-3, the length of the wing plates 3-7 is less than the length of the shift block 3-3, and the inner circumferential surface of the wing plates 3-7 and the outer circumferential surface of the transition connection portion 3-2 form a semi-cylindrical groove; when the piston rod 1 moves horizontally to the left and right extreme positions, the outer circumferential surface of the wing plates 3-7 contacts the step surface 1-1.

[0045] By symmetrically arranging the wing plates 3-7 on the left and right sides of the shift block 3-3, and connecting the free ends of the left wall profile surface 3-5 and the right wall profile surface 3-6 through an involute arc transition, the matching accuracy between the shift block 3-3 and the cylindrical pin is further improved to 0.01mm~0.2mm. Fig.10 As shown, the rotation angle of the shift fork 3 and the valve can be expanded from 90 degrees in Example 1 to 120 degrees, and has a self-locking function at the -15 degree position (the valve and the piston rod are at the right limit position) and the 105 degree position (the valve and the piston rod are at the left limit position).

[0046] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. An ultra-high load cylindrical pin type shift fork drive mechanism, comprising a piston rod (1), a shift fork (3) and a cylindrical pin (2), characterized in that: The piston rod (1) is arranged in the horizontal direction, a shift fork step surface (1-1) is arranged on the side wall of the piston rod (1), a step groove (1-2) is arranged in the middle of the shift fork step surface (1-1), and the length direction of the step groove (1-2) is perpendicular to the axial direction of the piston rod (1); the two cylindrical pins (2) are arranged in parallel at the opening position of the step groove (1-2), and the section where the side wall of the step groove (1-2) is located intersects with the outer circumferential surface of the corresponding side cylindrical pin (2); The shift fork (3) is an axisymmetric structure. The shift fork (3) comprises a cylindrical base (3-1), a transition connection portion (3-2) and a shift block (3-3). The transition connection portion (3-2) is fixedly arranged on the outer cylindrical surface of the base (3-1). The outer cylindrical surface of the root of the transition connection portion (3-2) is tangent to the outer cylindrical surface of the base (3-1). The outer cylindrical surface of the transition connection portion (3-2) is a quarter cylindrical surface. The arc radius of the quarter cylindrical surface is equal to the radius of the cylindrical surface. The radius of the pin (2); the root of the shift block (3-3) is fixedly connected to the transition connection part (3-2); the arc length of the root of the shift block (3-3) is equal to 1 / 2 of the spacing between the two cylindrical pins (2); the free end of the shift block (3-3) reciprocates in the clearance groove (1-2); according to the existing shift fork and cylindrical pin transmission structure, when the piston rod (1) drives the cylindrical pin (2) to move rightward, the cylindrical pin (2) cooperates with the right inner wall of the linear slide groove (4) The motion trajectory is used as the left side wall profile surface (3-5) of the shift block (3-3), and the motion trajectory of the cylindrical pin (2) cooperating with the left inner wall of the linear slide groove (4) when the piston rod (1) drives the cylindrical pin (2) to move leftward is used as the right side wall profile surface (3-6) of the shift block (3-3). The left side wall profile surface (3-5) and the right side wall profile surface (3-6) are symmetrically arranged; the outer cylindrical surfaces of the two cylindrical pins (2) are simultaneously cooperating with the left side wall profile surface (3-5) and the right side wall profile surface (3-6) of the shift block (3-3) for transmission, and at least one cylindrical pin (2) is always kept in cooperation with the outer cylindrical surface of the transition connection part (3-2) during the process of cooperating with the cylindrical pin (2) for transmission, and the piston rod (1) drives the shift block (3-3) to swing forward or backward to output torque through the cylindrical pin (2), and then drives the valve stem to rotate in the clockwise direction or counterclockwise direction through the shift fork (3), so as to realize the opening or closing of the valve.

2. The super-strong load cylindrical pin type fork drive mechanism according to claim 1, characterized in that: The rotation angle between the shift fork (3) and the valve is 90 degrees ± 10 degrees.

3. The ultra-high load cylindrical pin type fork drive mechanism according to claim 1, characterized in that: A bearing is installed on the cylindrical pin (2) at a position matching the shifting block (3-3).

4. The super-strong load cylindrical pin type fork drive mechanism according to claim 3, characterized in that: The bearing is a heavy-duty needle roller bearing or an oil film bearing.

5. The ultra-high load cylindrical pin type fork drive mechanism according to claim 1, characterized in that: The free end of the left wall contour surface (3-5) and the free end of the right wall contour surface (3-6) are connected through an involute arc surface transition.

6. The ultra-high load cylindrical pin type fork drive mechanism according to claim 1, characterized in that: Wing plates (3-7) are symmetrically arranged on the outer circumferential surface of the base body (3-1) and on the left and right sides of the shift block (3-3); the length of the wing plates (3-7) is less than the length of the shift block (3-3); the inner circumferential surface of the wing plates (3-7) and the outer circumferential surface of the transition connection portion (3-2) form a semi-cylindrical groove; when the piston rod (1) moves in the horizontal direction to the left or right extreme positions, the outer circumferential surface of the wing plates (3-7) contacts the step surface (1-1).

7. The super-strong load cylindrical pin type fork drive mechanism according to claim 6, characterized in that: The base body (3-1), the transition connection portion (3-2), the shift block (3-3) and the wing plate (3-7) are integrally formed.

8. The super-strong load cylindrical pin type fork drive mechanism according to claim 6, characterized in that: The rotation angle between the shift fork (3) and the valve is 120 degrees ± 5 degrees, and the valve has a self-locking function at the extreme rotation position.

9. The super-strong load cylindrical pin type fork drive mechanism according to claim 1 or 6, characterized in that: The thickness of the shifting block (3-3) is no greater than the length of the cylindrical pin (2).

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