Main reducer and differential assembly structure for forklift

Abstract

The main reducer and differential mechanism assembly structure comprises a main reducer assembly and a differential mechanism assembly, the main reducer assembly comprises a main reducer front shell, a main reducer middle shell and a main reducer rear shell, and an input flange and a spiral bevel gear driving gear shaft are arranged between the main reducer middle shell and the main reducer rear shell. The input flange is connected with a first bevel gear; a driving gear shaft of the spiral bevel gear is connected with a second bevel gear; the first bevel gear is meshed with the second bevel gear; the differential mechanism assembly comprises a right differential mechanism shell and a left differential mechanism shell. Spiral bevel gear driven disc teeth are installed on the right differential mechanism shell. And the spiral bevel gear driving gear shaft is meshed with the spiral bevel gear driven disc gear. According to the main reducer and differential mechanism assembly structure for the forklift, flexible connection can be achieved, a suspension vibration reduction mechanism can be conveniently arranged between the transmission and the main reducer and differential mechanism assembly, active vibration reduction measures are adopted to isolate and attenuate vibration transmitted to a frame by an engine, vibration of the whole forklift is reduced, and operation comfort is improved.

Description

Technical Field

[0001] This utility model relates to the field of forklift manufacturing technology, and more specifically, to a main reduction gear and differential assembly structure for forklifts. Background Technology

[0002] Currently, the transmission system used in domestic 2t-3.5t small wheelbase hydraulic internal combustion forklifts is a rigid connection, consisting of a hydraulic torque converter, hydraulic gearbox, main reducer and differential assembly, and drive axle assembly. The main reducer and differential assembly of this transmission system shares a housing with the hydraulic gearbox, forming an integral structure. The main reducer and differential assembly are assembled to the drive axle via flanges and bolts on the hydraulic housing. On the frame (forklift chassis), the transmission (including the hydraulic torque converter and hydraulic gearbox) at the rear of the transmission system is bolted to the internal combustion engine, with rubber damping pads placed between the engine mounting bracket and the frame. The drive axle at the front of the transmission system is fixed to the frame via a Haval mechanism. This structure has the following main drawbacks: for internal combustion forklifts, the main source of vibration is the engine, especially during engine start-up (torsional vibration) and idling (vibration is significant). Although rubber damping pads are installed between the engine mounting bracket and the chassis to weaken or even isolate vibrations directly transmitted from the engine to the chassis, the transmission is rigidly connected, and there are no suspension damping mechanisms between the main reduction gear and differential assembly and the transmission. Engine vibrations are transmitted from the drive axle to the chassis through the transmission, and then the chassis spreads the vibrations to various parts of the vehicle, resulting in large vehicle vibrations and poor handling comfort.

[0003] Due to the limitations of the existing structure of the main reduction gear and differential assembly, it is difficult to install a suspension damping mechanism between the main reduction gear and differential assembly and the transmission, so as to attenuate or even isolate the vibration transmitted from the engine to the whole vehicle through the transmission.

[0004] Therefore, there is an urgent need for a new main reduction gear and differential assembly structure for forklifts. Utility Model Content

[0005] The purpose of this utility model is to provide a main reduction gear and differential assembly structure for forklifts to solve the problems in the prior art. It can realize flexible connection of the transmission device and facilitate the installation of a suspension damping mechanism between the transmission and the main reduction gear and differential assembly to take active damping measures to isolate and attenuate the vibration transmitted from the engine to the frame, thereby reducing the overall vehicle vibration and improving the driving comfort.

[0006] This utility model provides a main reduction gear and differential assembly structure for a forklift, comprising: a main reduction gear assembly and a differential assembly, wherein:

[0007] The main reduction assembly includes a front housing, an intermediate housing, and a rear housing arranged sequentially. An input flange and a spiral bevel gear drive shaft are provided between the intermediate housing and the rear housing. The input flange is connected to a first helical gear. The spiral bevel gear drive shaft is connected to a second helical gear. The first helical gear and the second helical gear mesh to serve as the first stage reduction transmission gear of the main reduction assembly.

[0008] The differential assembly includes a right differential housing and a left differential housing, and a spiral bevel gear driven disc is mounted on the right differential housing;

[0009] The spiral bevel gear driving gear shaft and the spiral bevel gear driven disc mesh, serving as the second-stage reduction transmission gear of the main reduction assembly.

[0010] In the forklift main reducer and differential assembly structure described above, preferably, the main reducer front housing, the main reducer intermediate housing, and the main reducer rear housing are assembled by long bolts. Threaded holes are provided on the main reducer front housing and the main reducer rear housing. Several locating pins are used for assembly and positioning between the main reducer front housing and the main reducer intermediate housing, and between the main reducer intermediate housing and the main reducer rear housing. The main reducer rear housing is provided with a rotary oil seal and a rear cover for sealing. The rear cover is fixed to the main reducer rear housing by multiple bolts. The main reducer rear housing is equipped with a left and right bracket for the shock absorber pad of the suspension damping mechanism.

[0011] In the forklift main reduction gear and differential assembly structure described above, preferably, the two ends of the input flange are mounted between the intermediate housing and the rear housing of the main reduction gear via a first ball bearing and a second ball bearing, and the first helical gear is mounted on a splined shaft in the middle of the input flange; the input flange is axially limited by a thrust washer and bolts, and a thrust locking plate is installed between the thrust washer and the bolts.

[0012] In the forklift main reduction gear and differential assembly structure described above, preferably, the two ends of the spiral bevel gear drive shaft are mounted between the main reduction gear intermediate housing and the main reduction gear rear housing via a first tapered roller bearing and a second tapered roller bearing; the second helical gear is mounted on the splined shaft in the middle of the spiral bevel gear drive shaft; and a washer and a lock nut are installed at the root of the spiral bevel gear drive shaft.

[0013] In the forklift main reduction gear and differential assembly structure described above, preferably, a first adjusting shim is installed between the main reduction gear intermediate housing and the second tapered roller bearing, and a second adjusting shim is installed between the second helical gear and the first tapered roller bearing.

[0014] In the forklift main reduction gear and differential assembly structure described above, preferably, a planetary gear and a half-shaft gear are provided between the left differential housing and the right differential housing.

[0015] In the forklift main reducer and differential assembly structure described above, preferably, a cross shaft is installed between the left differential housing and the right differential housing, the planetary gear is mounted on the cross shaft, thrust washers are respectively provided between the planetary gear and the left differential housing and the right differential housing, and shims are respectively provided between the half-shaft gear and the left differential housing and the right differential housing.

[0016] In the forklift main reduction gear and differential assembly structure described above, preferably, the left differential housing, the right differential housing, and the driven gear of the spiral bevel gear are installed by bolts, and a locking plate is provided between the bolts and the left differential housing.

[0017] In the forklift main reduction gear and differential assembly structure described above, preferably, the main reduction gear front housing is bolted to a bearing housing, and adjusting nuts are respectively installed on both sides between the main reduction gear front housing and the bearing housing. A locking plate is provided between the bearing housing and the adjusting nuts, the claws of the locking plate are engaged in the ratchet groove of the adjusting nut, and the locking plate is fixed by bolts installed on the bearing housing.

[0018] In the forklift main reduction gear and differential assembly structure described above, preferably, the left differential housing and the right differential housing are mounted between the main reduction gear front housing and the bearing housing via bearings at both ends.

[0019] This utility model provides a main reduction gear and differential assembly structure for forklifts, which enables flexible connection of the transmission device. It facilitates the installation of a suspension damping mechanism between the transmission and the main reduction gear and differential assembly to take active damping measures to isolate and attenuate the vibration transmitted from the engine to the frame, thereby reducing overall vehicle vibration and improving handling comfort. By adopting quasi-hyperboloid spiral bevel gears, the overlap ratio can be increased from about 2 to more than 3, which not only improves the smoothness of transmission, but also increases the bending strength of the gear tooth root by about 30%. The quasi-hyperboloid spiral bevel gears have a maximum helix angle of up to 50°, so the equivalent radius of curvature of the meshing teeth is larger than that of the corresponding spiral bevel gears, which improves the tooth surface contact strength of the gears. Attached Figure Description

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the utility model will be further described below with reference to the accompanying drawings, wherein:

[0021] Figure 1 A schematic diagram of an embodiment of the main reduction gear and differential assembly for forklifts provided by this utility model;

[0022] Figure 2 Main reducer assembly structural diagram;

[0023] Figure 3 Main reduction assembly housing assembly structure diagram;

[0024] Figure 4 Input the flange assembly structure diagram;

[0025] Figure 5 This is an assembly structural diagram of the spiral bevel gear drive shaft assembly.

[0026] Figure 6 This is a structural diagram of the differential assembly;

[0027] Figure 7 This is a structural diagram of the differential housing and the driven gear of the spiral bevel gear assembly.

[0028] Figure 8 This is a structural diagram of the main reducer housing and bearing seat assembly.

[0029] Explanation of reference numerals in the attached diagram: 11-Main reduction gear assembly, 12-Differential gear assembly, 1101-Front housing of main reduction gear, 1102-Second tapered roller bearing, 1103-Intermediate housing of main reduction gear, 1104-Helical bevel gear drive shaft, 1105-Second helical gear, 1106-Rear housing of main reduction gear, 1107-First tapered roller bearing, 1108-Washer, 1109-Locking nut, 1110-Rear cover, 1111-Input flange, 1112-Rotary oil seal, 1113-Second ball bearing, 1114-First helical gear, 1115-First ball bearing, 1116-Shock absorber 1117-Right shock absorber pad, 1118-Positioning pin, 1119-Thrust washer, 1120-Thrust lock plate, 1121-Second adjusting shim, 1122-First adjusting shim, 1201-Bearing, 1202-Spiral bevel gear driven disc, 1203-Right differential housing, 1204-Thrust washer, 1205-Planetary gear, 1206-Left differential housing, 1207-Shim, 1208-Cross shaft, 1209-Half shaft gear, 1210-Locking shim, 1211-Adjusting nut, 1212-Bearing housing, 1213-Locking plate. Detailed Implementation

[0030] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0031] The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Terms such as “including” or “contains” mean that the element preceding the term encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as “above” and “below” are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0032] In this disclosure, when a specific component is described as being located between a first component and a second component, an intermediary component may or may not be present between the specific component and the first or second component. When a specific component is described as connecting to other components, the specific component may be directly connected to the other components without having an intermediary component, or it may not be directly connected to the other components but may have an intermediary component.

[0033] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0034] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0035] like Figures 1-8 As shown, the forklift main reduction gear and differential assembly structure provided in this embodiment includes: a main reduction gear assembly 11 and a differential assembly 12, wherein:

[0036] The main reduction assembly 11 includes a front housing 1101, an intermediate housing 1103, and a rear housing 1106 arranged sequentially. An input flange 1111 and a spiral bevel gear drive shaft 1104 are provided between the intermediate housing 1103 and the rear housing 1106. A first helical gear 1114 is connected to the input flange 1111; a second helical gear 1105 is connected to the spiral bevel gear drive shaft 1104; the first helical gear 1114 and the second helical gear 1105 mesh to serve as the first stage reduction transmission gear of the main reduction assembly 11.

[0037] The differential assembly 12 includes a right differential housing 1203 and a left differential housing 1206, and a spiral bevel gear driven disc 1202 is mounted on the right differential housing 1203.

[0038] The spiral bevel gear drive shaft 1104 and the spiral bevel gear driven disc 1202 mesh together, serving as the second-stage reduction transmission gear of the main reduction assembly 11.

[0039] The main reduction assembly 11 is primarily used to reduce the rotational speed, increase the torque transmitted to the drive wheels, and rotate the axis of rotation 90° to transmit power to the half-shafts and wheels. The differential assembly 12 is mainly used to achieve differential transmission between the left and right vehicles to prevent the left and right wheels from slipping on the ground. The main reduction assembly 11 has two-stage reduction transmission: the first stage is a cylindrical helical gear transmission, and the second stage is a quasi-hyperboloid spiral bevel gear transmission.

[0040] Furthermore, the driving gear shaft 1104 and the driven gear disc 1202 of the spiral bevel gear adopt quasi-hyperboloid spiral bevel gears, which can increase the overlap ratio from about 2 to more than 3. This not only improves the smoothness of transmission, but also increases the bending strength of the gear tooth root by about 30%. With the adoption of quasi-hyperboloid spiral bevel gears, the maximum helix angle can reach 50° (the helix angle of arc bevel gears is generally 35°, and the maximum does not exceed 40°). Therefore, the equivalent radius of curvature of the meshing gear teeth is larger than that of the corresponding arc bevel gears, which improves the tooth surface contact strength of the gears.

[0041] Specifically, such as Figure 3As shown, the main reduction gear front housing 1101, the main reduction gear intermediate housing 1103, and the main reduction gear rear housing 1106 are assembled by long bolts. Threaded holes are provided on the main reduction gear front housing 1101 and the main reduction gear rear housing 1106. In specific implementations, bolts can be inserted from both sides of the main reduction gear front housing 1101 and the main reduction gear rear housing 1106 according to the arrangement of the threaded holes. A plurality of locating pins 1118 are used for assembly and positioning between the main reduction gear front housing 1101 and the main reduction gear intermediate housing 1103, and between the main reduction gear intermediate housing 1103 and the main reduction gear rear housing 1106. The number of locating pins 1118 is two, their shape is circular, and their type is B10. It should be noted that this utility model does not specifically limit the number, shape, or type of the locating pins 1118. The main reducer rear housing 1106 is sealed with a rotary oil seal 1112 and a rear cover 1110. The rear cover 1110 is fixed to the main reducer rear housing 1106 by multiple bolts, specifically four bolts. The main reducer rear housing 1106 is equipped with a left damping pad bracket 1116 and a right damping pad bracket 1117 for the suspension damping mechanism. This invention changes the connection between the main reducer and differential assembly and the transmission from a rigid connection to a flexible connection, using a universal joint for power transmission. This facilitates the arrangement of the suspension damping mechanism between the transmission and the main reducer and differential assembly. Testing shows that its overall vehicle vibration value is reduced by approximately 50% compared to existing products.

[0042] Furthermore, such as Figure 2 As shown, the two ends of the input flange 1111 are mounted between the main reduction intermediate housing 1103 and the main reduction rear housing 1106 via a first ball bearing 1115 and a second ball bearing 1113. The first helical gear 1114 is radially supported on both sides by the first ball bearing 1115 and the second ball bearing 1113. For example, the first ball bearing 1115 is model 6208, and the second ball bearing 1113 is model 6209. The first helical gear 1114 is mounted on a splined shaft in the middle of the input flange 1111 and serves as the driving gear for the first-stage reduction. The input flange 1111 is axially limited by a thrust washer 1119 and bolts. A thrust locking plate 1120 is installed between the thrust washer 1119 and the bolts to prevent loosening.

[0043] Furthermore, such as Figure 2 and Figure 5As shown, the two ends of the spiral bevel gear drive shaft 1104 are mounted between the main reduction intermediate housing 1103 and the main reduction rear housing 1106 via a first tapered roller bearing 1107 and a second tapered roller bearing 1102. For example, the first tapered roller bearing 1107 is model HR30308J, and the second tapered roller bearing 1102 is model HR30309J. The second helical gear 1105 is mounted on the splined shaft in the middle of the spiral bevel gear drive shaft 1104. The second helical gear 1105 is radially supported on both sides by the first tapered roller bearing 1107 and the second tapered roller bearing 1102, serving as the driven gear for the first stage of reduction. A washer 1108 and a lock nut 1109 are installed at the root of the spiral bevel gear drive shaft 1104, providing axial positioning of the spiral bevel gear drive shaft 1104 via the lock nut 1109 and the washer 1108.

[0044] like Figure 5 As shown, a first adjusting shim 1122 is installed between the main reducer intermediate housing 1103 and the second tapered roller bearing 1102, and a second adjusting shim 1121 is installed between the second helical gear 1105 and the first tapered roller bearing 1107. The first adjusting shim 1122 can be, for example, ￠109.5×￠90. In one embodiment of this utility model, the thickness of the first adjusting shim 1122 has three specifications: 0.05mm, 0.1mm, and 0.2mm. The first adjusting shim 1122 can be used to adjust the mounting center distance between the spiral bevel gear drive shaft 1104 and the spiral bevel gear driven disc 1202. The second adjusting shim 1121 can be, for example, ￠55×￠45.5. The second adjusting shim 1121 can be used to adjust the axial clearance of the first tapered roller bearing 1107 and the second tapered roller bearing 1102 after the locking nut 1109 is tightened.

[0045] Furthermore, such as Figure 6 As shown, a planetary gear 1205 and a half-shaft gear 1209 are disposed between the left differential housing 1206 and the right differential housing 1203. Specifically, a cross shaft 1208 is installed between the left differential housing 1206 and the right differential housing 1203, the planetary gear 1205 is mounted on the cross shaft 1208, thrust washers 1204 are respectively disposed between the planetary gear 1205 and the left differential housing 1206 and the right differential housing 1203, and shims 1207 are respectively disposed between the half-shaft gear 1209 and the left differential housing 1206 and the right differential housing 1203.

[0046] like Figure 7As shown, the left differential housing 1206, the right differential housing 1203, and the driven spiral bevel gear 1202 are installed by bolts. A locking plate 1210 is provided between the bolts and the left differential housing 1206 to prevent loosening.

[0047] like Figure 8 As shown, the main reducer front housing 1101 is bolted to a bearing seat 1212. Adjusting nuts 1211 are installed on both sides between the main reducer front housing 1101 and the bearing seat 1212 to adjust the meshing backlash between the spiral bevel gear drive shaft 1104 and the spiral bevel gear driven disc teeth 1202, controlling its value between 0.15mm and 0.25mm. A locking piece 1213 is provided between the bearing seat 1212 and the adjusting nut 1211. The claws of the locking piece 1213 are engaged in the ratchet groove of the adjusting nut 1211, and the locking piece 1213 is fixed by bolts installed on the bearing seat 1212.

[0048] like Figure 6 As shown, the left differential housing 1206 and the right differential housing 1203 are mounted between the main reducer front housing 1101 and the bearing seat 1212 via bearings 1201 at both ends. For example, the bearing 1201 is model 30211.

[0049] The forklift main reduction gear and differential assembly structure provided in this embodiment of the utility model can realize flexible connection of the transmission device, which facilitates the installation of a suspension damping mechanism between the transmission and the main reduction gear and differential assembly, so as to take active damping measures to isolate and attenuate the vibration transmitted from the engine to the frame, thereby reducing the overall vehicle vibration and improving the driving comfort. The use of quasi-hyperboloid spiral bevel gears can increase the overlap ratio from about 2 to more than 3, which not only improves the smoothness of the transmission, but also increases the bending strength of the gear tooth root by about 30%. The quasi-hyperboloid spiral bevel gears have a maximum helix angle of up to 50°, so the equivalent radius of curvature of the meshing gear teeth is larger than that of the corresponding spiral bevel gears, which improves the tooth surface contact strength of the gears.

[0050] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0051] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A structure of a main reduction and differential assembly for a fork lift truck, characterized by, The application relates to a main reduction assembly and a differential assembly. The main reduction assembly comprises a main reduction front shell, a main reduction intermediate shell and a main reduction rear shell arranged in sequence, an input flange and a spiral bevel gear driving shaft are arranged between the main reduction intermediate shell and the main reduction rear shell, the input flange is connected with a first helical gear, the spiral bevel gear driving shaft is connected with a second helical gear, the first helical gear and the second helical gear are meshed and serve as first-stage reduction transmission gears of the main reduction assembly. The differential assembly comprises a right differential shell and a left differential shell, a spiral bevel gear driven disc is arranged on the right differential shell. The spiral bevel gear driving shaft and the spiral bevel gear driven disc are meshed and serve as second-stage reduction transmission gears of the main reduction assembly. The main reduction front shell, the main reduction intermediate shell and the main reduction rear shell are assembled by long bolts, threaded holes are formed in the main reduction front shell and the main reduction rear shell, a plurality of positioning pins are arranged between the main reduction front shell and the main reduction intermediate shell and between the main reduction intermediate shell and the main reduction rear shell for assembly and positioning, a rotary oil seal and a rear cover are arranged on the main reduction rear shell for sealing, the rear cover is fixed on the main reduction rear shell by a plurality of bolts, and a shock pad left support and a shock pad right support of a suspension damping mechanism are arranged on the main reduction rear shell. Both ends of the input flange are arranged between the main reduction intermediate shell and the main reduction rear shell by a first ball bearing and a second ball bearing, the first helical gear is arranged on a spline shaft in the middle of the input flange, the input flange is axially limited by a thrust washer and a bolt, and a thrust locking plate is arranged between the thrust washer and the bolt.

2. The forklift truck main reduction and differential assembly structure according to claim 1, characterized by, Both ends of the spiral bevel gear driving shaft are arranged between the main reduction intermediate shell and the main reduction rear shell by a first tapered roller bearing and a second tapered roller bearing, the second helical gear is arranged on a spline shaft in the middle of the spiral bevel gear driving shaft, and a washer and a locking nut are arranged on the root of the spiral bevel gear driving shaft.

3. The fork truck main reduction and differential assembly structure as set forth in claim 1, wherein, A first adjusting washer is arranged between the main reduction intermediate shell and the second tapered roller bearing, and a second adjusting washer is arranged between the second helical gear and the first tapered roller bearing.

4. The forklift truck main reduction and differential assembly structure as set forth in claim 3, wherein A planetary gear and a half shaft gear are arranged between the left differential shell and the right differential shell.

5. The fork truck main reduction and differential assembly structure as set forth in claim 1, wherein, A cross shaft is arranged between the left differential shell and the right differential shell, the planetary gear is arranged on the cross shaft, thrust washers are arranged between the planetary gear and the left differential shell and the right differential shell respectively, and washers are arranged between the half shaft gear and the left differential shell and the right differential shell respectively.

6. The forklift truck main reduction and differential assembly structure as set forth in claim 5, wherein The left differential shell, the right differential shell and the spiral bevel gear driven disc are arranged by bolts, and locking plates are arranged between the bolts and the left differential shell.

7. The fork truck main reduction and differential assembly structure as set forth in claim 1, wherein, ​ 8. The fork truck main reduction and differential assembly structure as set forth in claim 1, wherein, The main reduction front shell is bolted with a bearing seat, two sides between the main reduction front shell and the bearing seat are respectively equipped with adjusting nuts, a lock piece is arranged between the bearing seat and the adjusting nut, the paw of the lock piece is clamped in the ratchet groove of the adjusting nut, and the lock piece is fixed through the bolt installed on the bearing seat.

9. The fork truck main reduction and differential assembly structure as set forth in claim 8, wherein, The left differential shell and the right differential shell are installed between the main reduction front shell and the bearing seat through the bearings at two ends.

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