A floating rack and pinion steering axle structure

Abstract

The utility model discloses a kind of floating rack steering axle structures, belong to fork truck steering axle field. Including: slewing support, cylinder barrel assembly, floating rack assembly and support pinion shaft. Cylinder barrel assembly includes left cylinder barrel and right cylinder barrel, left cylinder barrel open end is fixedly inserted in the inside of slewing support left side interface, right cylinder barrel open end is fixedly inserted in the inside of slewing support right side interface;Floating rack assembly includes rack body, left piston and right piston, left piston is slidably embedded in left cylinder barrel, left piston is tightly attached to rack body left end, right piston is slidably embedded in right cylinder barrel, right piston is tightly attached to rack body right end;The top gear ring of support pinion shaft is engaged with the transmission gear portion opened in the middle part of rack body. The utility model reduces cylinder barrel machining precision requirement, assembly efficiency is improved by more than 20%, compresses slewing support axial space 15%-20%, oil seal life is extended to 2 times of traditional structure.

Description

Technical Field

[0001] This utility model relates to the field of forklift steering axle technology, specifically to a floating rack and pinion steering axle structure. Background Technology

[0002] Forklifts are being used more and more widely as material handling vehicles. Currently, the forklift market is showing diversified and refined development. In order to seize the market and meet customer needs, there are more and more forklifts with personalized requirements. Developing forklift steering axles to match for related niche markets has a large market potential.

[0003] Forklift steering axles need to meet the requirements of high precision, compactness, and high reliability. Traditional three-point steering axles use an integral rack and pinion structure, which has significant drawbacks:

[0004] High machining accuracy is required: the integral rack must be strictly coaxial with the cylinders at both ends (coaxiality ≤ 0.05mm), resulting in high machining costs and low yield.

[0005] Low assembly efficiency: The entire rack needs to be pressed into both cylinders simultaneously, which is time-consuming and can easily damage the sealing rings.

[0006] Limited space layout: The overall rack length is fixed, making it difficult to adapt to compact vehicle designs;

[0007] Poor sealing reliability: Deviation in cylinder coaxiality can easily lead to uneven wear and leakage of the oil seal. Utility Model Content

[0008] This invention provides a floating rack and pinion steering axle structure, which can solve the problems of high machining accuracy requirements, low assembly efficiency, limited space layout, and poor sealing reliability of existing forklift steering axles using integral rack and pinion structures.

[0009] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0010] A floating rack and pinion steering axle structure includes:

[0011] Slewing bearing, used for fixed connection with the vehicle seat;

[0012] A cylinder assembly, comprising a left cylinder and a right cylinder, wherein the open end of the left cylinder is fixedly inserted into the left side interface of the slewing support, and the open end of the right cylinder is fixedly inserted into the right side interface of the slewing support.

[0013] A floating rack assembly includes a rack body, a left piston, and a right piston. The left piston is slidably embedded in the left cylinder and is in close contact with the left end of the rack body. The right piston is slidably embedded in the right cylinder and is in close contact with the right end of the rack body.

[0014] A support gear shaft, the top gear ring of which meshes with a transmission gear portion located in the middle of the rack body.

[0015] As a further embodiment of this utility model: a steering wheel shaft is fixedly installed inside the bottom sleeve of the support gear shaft, and wheel hubs are rotatably connected to both ends of the steering wheel shaft.

[0016] As a further embodiment of this utility model: a left support ring is nested in the middle of the left piston, and the outer peripheral wall of the left support ring slides against the inner wall of the left cylinder.

[0017] As a further embodiment of this utility model: a left sealing ring is also nested on the left piston end side, the outer peripheral wall of the left sealing ring slides against the inner wall of the left cylinder, and the two left sealing rings are symmetrically arranged on both sides of the left support ring.

[0018] As a further embodiment of this utility model: a right support ring is nested in the middle of the right piston, and the outer peripheral wall of the right support ring slides against the inner wall of the right cylinder.

[0019] As a further embodiment of this utility model: right sealing rings are also nested at both ends of the right piston, the outer peripheral wall of the right sealing ring slides against the inner wall of the right cylinder, and the two right sealing rings are symmetrically arranged on both sides of the right support ring.

[0020] As a further embodiment of this utility model: the left support ring and the right support ring are open rings with an opening gap of 0.5-1mm.

[0021] As a further embodiment of this utility model: the slewing support has an axially through hollow cavity in the middle, and the transmission teeth in the middle of the rack body are exposed in the hollow cavity.

[0022] As a further embodiment of this utility model: the inner walls of the left cylinder and the right cylinder are plated with a hard chrome layer, and the surface roughness Ra≤0.4μm.

[0023] As a further embodiment of this utility model: the fitting clearance between the outer diameter of the left piston and the right piston and the inner diameter of the left cylinder and the right cylinder is 0.05-0.08mm.

[0024] The beneficial effects of this utility model are:

[0025] (1) This utility model adopts a floating rack structure. The rack body has two independent pistons at both ends. The two pistons cooperate with the corresponding cylinders individually. The independent pistons adapt to the inner wall of the corresponding cylinders and can achieve self-centering. Therefore, the sealing performance of the oil cylinder is not affected by the coaxiality of the cylinders at both ends, eliminating the influence of coaxiality deviation, reducing processing requirements and process difficulty, and improving sealing reliability.

[0026] (2) Compared with the integral rack, the floating rack of this utility model can be assembled simply by installing the piston into the corresponding cylinder and connecting it to both ends of the rack body. The assembly process is better and the assembly efficiency can be improved by about 20%.

[0027] (3) The floating rack structure of this utility model has an adjustable rack length, which can compress the axial space of the rotary support by 15%-20%, so as to meet the requirements of compact space layout.

[0028] (4) The piston of this utility model adopts a double sealing structure of support ring and sealing ring, and the oil seal life is extended to twice that of the traditional structure. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] Figure 1 This is a schematic diagram of a floating rack and pinion steering bridge structure according to this utility model;

[0031] Figure 2 yes Figure 1 Top view sectional diagram of the structure;

[0032] Figure 3 This is a schematic diagram of the internal structure of the slewing bearing;

[0033] Figure 4 This is a schematic diagram of the internal structure of the left and right cylinder barrels;

[0034] Figure 5 This is a schematic diagram of the internal structure of the hollow cavity.

[0035] In the diagram: 1. Rotary bearing; 2. Left cylinder; 3. Right cylinder; 4. Rack body; 5. Left piston; 6. Right piston; 7. Support gear shaft; 8. Steering wheel shaft; 9. Wheel hub; 10. Left support ring; 11. Left sealing ring; 12. Right support ring; 13. Right sealing ring; 14. Hollow cavity; 15. Locating pin. Detailed Implementation

[0036] The technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0037] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on this utility model.

[0038] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0039] Please see Figure 1-5 As shown, this utility model embodiment provides a floating rack steering axle structure, including a slewing support 1, a cylinder assembly, a floating rack assembly, a supporting gear shaft 7, and a hub component 9.

[0040] The slewing bearing 1 is used for fixed installation at the bottom of the vehicle seat. The slewing bearing 1 is a cast steel part, and the slewing bearing 1 has an axially through hollow cavity 14 in the middle. The hollow cavity 14 design reduces the axial dimension of the slewing bearing 1 to 82% of that of the traditional structure.

[0041] Please see Figure 1 As shown, the cylinder assembly includes a left cylinder 2 and a right cylinder 3. The open end of the left cylinder 2 is fixedly welded to the inside of the left interface of the hollow cavity 14 of the rotary support 1, and the open end of the right cylinder 3 is fixedly welded to the inside of the right interface of the hollow cavity 14 of the rotary support 1. The fitting clearance between the outer diameter of the left piston 5 and the right piston 6 and the inner diameter of the left cylinder 2 and the right cylinder 3 is 0.05-0.08mm.

[0042] Please see Figure 2 As shown, the floating rack assembly includes a rack body 4, a left piston 5, and a right piston 6. The drive teeth in the middle of the rack body 4 are exposed within the hollow cavity 14. The left piston 5 is slidably embedded in the left cylinder 2, and is in close contact with the left end of the rack body 4. The right piston 6 is slidably embedded in the right cylinder 3, and is in close contact with the right end of the rack body 4. The left piston 5 can reciprocate left and right within the left cylinder 2, thereby pushing the rack body 4 to move within the hollow cavity 14. Similarly, the right piston 6 can also reciprocate left and right within the right cylinder 3, thereby pushing the rack body 4 to move within the hollow cavity 14.

[0043] Please see Figure 3As shown, the top gear ring of the supporting gear shaft 7 meshes with the transmission gear in the middle of the rack body 4. Thus, when the rack body 4 moves within the hollow cavity 14, the rack body 4 can drive the supporting gear shaft 7 to rotate.

[0044] Please see Figure 1 As shown, a steering wheel shaft 8 is fixedly installed in the bottom sleeve of the support gear shaft 7 by a locating pin 15. Both ends of the steering wheel shaft 8 are rotatably connected to the wheel hub 9 by tapered roller bearings. When the rack body 4 drives the support gear shaft 7 to rotate, the support gear shaft 7 drives the wheel hub 9 to turn through the steering wheel shaft 8.

[0045] Further, please refer to Figure 4 As shown, a left support ring 10 is nested in the middle of the left piston 5, and the outer peripheral wall of the left support ring 10 slides against the inner wall of the left cylinder 2. A left sealing ring 11 is also nested at one end of the left piston 5, and the outer peripheral wall of the left sealing ring 11 slides against the inner wall of the left cylinder 2. The two left sealing rings 11 are symmetrically arranged on both sides of the left support ring 10. The arrangement of the left support ring 10 and the left sealing ring 11 improves the sealing performance of the left piston 5 during its sliding process within the left cylinder 2, preventing oil leakage from the left cylinder 2. A right support ring 12 is nested in the middle of the right piston 6, and the outer peripheral wall of the right support ring 12 slides against the inner wall of the right cylinder 3. Right sealing rings 13 are also nested at both ends of the right piston 6, and the outer peripheral wall of the right sealing ring 13 slides against the inner wall of the right cylinder 3. The two right sealing rings 13 are symmetrically arranged on both sides of the right support ring 12. The arrangement of the right support ring 12 and the right sealing ring 13 improves the sealing performance of the right piston 6 during its sliding process within the right cylinder 3, preventing oil leakage from the right cylinder 3.

[0046] The left sealing ring 11 and the right sealing ring 13 have a double-lip structure. The left support ring 10 and the right support ring 12 are open-type PTFE composite rings with an embedded bronze powder reinforcement layer; the opening gap of the ring body is 0.5-1mm. The open design of the PTFE ring allows for thermal expansion deformation and avoids ring body cracking; the thermal conductivity of the bronze powder layer (801) is ≥50W / (m·K), which quickly dissipates frictional heat and prevents the left sealing ring 11 and the right sealing ring 13 from failing at high temperatures.

[0047] Furthermore, a hard chrome plating layer can be applied to the inner walls of the left cylinder 2 and the right cylinder 3, with a surface roughness Ra≤0.4μm. This improves the sealing performance and high-temperature resistance of the inner walls of the left cylinder 2 and the right cylinder 3.

[0048] Assembly process:

[0049] The open ends of the left cylinder 2 and the right cylinder 3 are welded and fixed to the left and right interfaces of the hollow cavity 14 of the rotary support 1, respectively.

[0050] The left piston 5 and the right piston 6 are pressed into the left cylinder 2 and the right cylinder 3 respectively. The left piston 5 achieves radial sealing with the inner wall of the left cylinder 2 through the left sealing ring 11 and the left support ring 10. The right piston 6 achieves radial sealing with the inner wall of the right cylinder 3 through the right sealing ring 13 and the right support ring 12.

[0051] The left piston 5 and the right piston 6 are rigidly connected to both ends of the rack body 4, and the support gear shaft 7 meshes with the transmission teeth in the middle of the rack body 4.

[0052] Working principle:

[0053] Hydraulic oil enters the left cylinder 2 or the right cylinder 3, driving the left piston 5 or the right piston 6 to move. The movement of the left piston 5 or the right piston 6 pushes the rack body 4 to move, and the movement of the rack body 4 drives the support gear shaft 7 to rotate, thereby realizing the steering of the wheel hub assembly.

[0054] The floating rack and pinion steering axle structure provided by this utility model has the following advantages:

[0055] Self-centering seal; the rack body 4 has two independent pistons at both ends, which individually cooperate with the corresponding cylinder. The independent pistons adapt to the inner wall of the cylinder and can achieve self-centering. Therefore, the sealing performance of the oil cylinder is not affected by the coaxiality of the cylinders at both ends, eliminating the influence of coaxiality deviation, reducing processing requirements and process difficulty, and improving sealing reliability.

[0056] Improved assembly processability and efficiency: Compared with integral rack, floating rack only requires the piston to be installed into the corresponding cylinder and then connected to both ends of rack body 4 to complete the assembly. The assembly processability is better and the assembly efficiency can be improved by about 20%.

[0057] Optimize spatial layout: The floating rack and pinion structure can compress the space of the rotary support 1, so as to meet the requirements of a compact spatial layout.

[0058] The preferred embodiments of this utility model have been described in detail above and should not be considered as limiting the scope of this utility model. All equivalent changes and improvements made within the scope of the claims of this utility model should still fall within the patent coverage of this utility model.

Claims

1. A floating rack and pinion steering axle structure, characterized in that, include: Slewing bearing (1), used for fixed connection with the car seat; The cylinder assembly includes a left cylinder (2) and a right cylinder (3). The open end of the left cylinder (2) is fixedly inserted into the left side interface of the rotary support (1), and the open end of the right cylinder (3) is fixedly inserted into the right side interface of the rotary support (1). A floating rack assembly, comprising a rack body (4), a left piston (5) and a right piston (6), wherein the left piston (5) is slidably embedded in the left cylinder (2) and is in close contact with the left end of the rack body (4), and the right piston (6) is slidably embedded in the right cylinder (3) and is in close contact with the right end of the rack body (4); The top gear ring of the support gear shaft (7) meshes with the transmission gear section opened in the middle of the rack body (4).

2. The floating rack and pinion steering axle structure according to claim 1, characterized in that: The bottom sleeve of the support gear shaft (7) is fixedly installed with a steering wheel shaft (8), and the two ends of the steering wheel shaft (8) are respectively rotatably connected with wheel hubs (9).

3. The floating rack and pinion steering axle structure according to claim 1, characterized in that: The left piston (5) has a left support ring (10) nested in the middle, and the outer peripheral wall of the left support ring (10) slides against the inner wall of the left cylinder (2).

4. The floating rack and pinion steering axle structure according to claim 3, characterized in that: The left piston (5) is also nested with a left sealing ring (11). The outer peripheral wall of the left sealing ring (11) slides against the inner wall of the left cylinder (2). The two left sealing rings (11) are symmetrically arranged on both sides of the left support ring (10).

5. A floating rack and pinion steering axle structure according to claim 4, characterized in that: The right piston (6) has a right support ring (12) nested in the middle, and the outer peripheral wall of the right support ring (12) slides against the inner wall of the right cylinder (3).

6. A floating rack and pinion steering axle structure according to claim 5, characterized in that: The right piston (6) is also nested with right sealing rings (13) at both ends. The outer peripheral wall of the right sealing ring (13) slides against the inner wall of the right cylinder (3). The two right sealing rings (13) are symmetrically arranged on both sides of the right support ring (12).

7. A floating rack and pinion steering axle structure according to claim 6, characterized in that: The left support ring and the right support ring are open rings with an opening gap of 0.5-1mm.

8. A floating rack and pinion steering axle structure according to claim 1, characterized in that: The rotary support (1) has an axially through hollow cavity (14) in the middle, and the transmission teeth of the rack body (4) are exposed in the hollow cavity (14).

9. A floating rack and pinion steering axle structure according to claim 1, characterized in that: The inner walls of the left cylinder (2) and the right cylinder (3) are plated with a hard chromium layer, and the surface roughness Ra ≤ 0.4 μm.

10. A floating rack and pinion steering axle structure according to claim 1, characterized in that: The clearance between the outer diameter of the left piston (5) and the right piston (6) and the inner diameter of the left cylinder (2) and the right cylinder (3) is 0.05-0.08 mm.

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