Heavy-duty commercial vehicle transmission main box intermediate shaft assembly

Abstract

The utility model relates to a transmission intermediate shaft assembly, in particular to a transmission main box intermediate shaft assembly of a heavy commercial vehicle. The utility model aims to improve the torque transmission capacity of the intermediate shaft of a main box and solve the problem that the fault rate of a large-torque transmission of a heavy commercial vehicle is high due to low positioning and use reliability of a gear set on an intermediate shaft of an existing transmission. The main box intermediate shaft comprises a main box intermediate shaft, an intermediate shaft gear set is in interference fit with a connecting part of the main box intermediate shaft, and a positioning hole is formed in a hub of each gear in the intermediate shaft gear set; positioning blind holes with the same size are formed in the corresponding positions of the connecting part, and a plurality of positioning pins are sequentially installed in the positioning holes and the positioning blind holes which correspond in pairs; according to the utility model, through the combination of the interference connection of the intermediate shaft gear set and the main box intermediate shaft and the positioning of the positioning pin, the positioning precision is effectively enhanced, the torque transmission capability of the main box intermediate shaft is improved, and the transmission mechanism is more suitable for a high-power-density gearbox and a matched high-horsepower engine.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of gearboxes, specifically to a kind of heavy commercial vehicle gearbox main case middle shaft assembly. BACKGROUND

[0002] Heavy commercial vehicle as the main equipment of highway freight transport, because of its heavy load, long-distance transportation cost-effective, occupies an important position in the market. As the core component of heavy commercial vehicle, the average life and reliability of gearbox directly affect the performance indicators of the whole vehicle. With the application of high-power engine, the corresponding heavy commercial vehicle gearbox development is imminent. Among them, the main case middle shaft assembly as the key component of heavy commercial vehicle gearbox, the positioning mode of gear set on it is often simple bearing limiting or welding positioning. With the improvement of power requirement of gearbox, the positioning precision and torque capacity of the two methods currently reached gradually cannot meet the use demand, which is manifested as high failure rate in actual application, lack of reliability, leading to the increase of after-sales claim rate, the maintenance cost is increased, which is not conducive to the output of high-quality products.

[0003] Chinese patent CN216112045U discloses a kind of gearbox middle shaft and gearbox, wherein the middle shaft of gearbox is provided with through hole along the axial direction;Gear set of middle shaft is arranged on the connecting part of middle shaft, and is positioned by solid positioning pin;Chinese patent CN212672359U discloses a kind of gearbox middle shaft assembly and gearbox, wherein a part of first gear and second gear is in interference fit with middle shaft, and another part is in clearance fit with involute spline respectively. However, the gear set of middle shaft in the above-mentioned scheme is connected only by positioning pin, and the other is connected only by interference fit;In heavy commercial vehicle gearbox, such connection mode cannot guarantee the positioning precision and use reliability of gear set;In addition, with the improvement of power density of gearbox, its rotating speed and torque gradually increase, and the axial displacement displacement also increases, which leads to the solid positioning pin in the first scheme to be easily deformed by the influence of contact part creep at the joint surface of two parts, thereby increasing the failure rate. UTILITY MODEL CONTENTS

[0004] The main purpose of the utility model is to solve the positioning and use reliability of the gear set on the existing gearbox middle shaft, which is low and easy to cause high failure rate of heavy commercial vehicle gearbox, and to improve the torque capacity of main case middle shaft, and to provide a kind of heavy commercial vehicle gearbox main case middle shaft assembly.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions:

[0006] A kind of heavy commercial vehicle gearbox main case middle shaft assembly, comprising: main case middle shaft and middle shaft gear set;

[0007] The main case intermediate shaft comprises, in sequence from one end to the other end in the axial direction, an external spline section, a connecting section and a helical tooth section;

[0008] The intermediate shaft gear set is mounted on the connecting section of the main case intermediate shaft;

[0009] It is characterized in that:

[0010] The intermediate shaft gear set and the connecting section of the main case intermediate shaft are in interference fit;

[0011] A positioning hole is radially formed on the hub of each gear in the intermediate shaft gear set, and a positioning blind hole is radially formed on the connecting section of the main case intermediate shaft at a position corresponding to each positioning hole; a plurality of positioning pins are respectively installed in each pair of corresponding positioning holes and positioning blind holes, further positioning and fastening the intermediate shaft gear set on the main case intermediate shaft;

[0012] An annular groove is circumferentially formed on the outer wall of each positioning pin, and the position of the annular groove corresponds to the position of the joint of the connecting section of the main case intermediate shaft and each gear in the intermediate shaft gear set, so as to ensure that the outer wall of the concave positioning pin does not directly contact the hole wall of the part joint surface while achieving precise positioning; the distance between the upper edge of the annular groove and the axis of the main case intermediate shaft is defined as R1, the distance between the lower edge and the axis of the main case intermediate shaft is defined as R2, and the radius of the connecting section of the main case intermediate shaft is defined as R, then R1>R>R2.

[0013] Further, the relationship between R1, R and R2 is as follows: (R1-R2) / 2=R-R2.

[0014] Further, the intermediate shaft gear set comprises a main case intermediate shaft double gear and a main case intermediate shaft transmission gear, the main case intermediate shaft double gear is installed on one side of the connecting section close to the external spline section, and the main case intermediate shaft transmission gear is installed on one side of the connecting section close to the helical tooth section; a hub is arranged on one side of the main case intermediate shaft transmission gear close to the main case intermediate shaft double gear, and a hub is arranged between the main case intermediate shaft double gears; the hub of the main case intermediate shaft transmission gear and the hub of the main case intermediate shaft double gear are fixed on the connecting section through the positioning pins.

[0015] Further, a reinforcing ring is sleeved on the hub of the main case intermediate shaft transmission gear, and the two are in interference fit, which is used to improve the transmission torque capacity of the main case intermediate shaft transmission gear; an installation hole is radially formed on the reinforcing ring at a position corresponding to the positioning hole on the hub of the main case intermediate shaft transmission gear, so that the positioning pin can pass through the installation hole and be installed in the positioning hole on the intermediate shaft transmission gear and the corresponding positioning blind hole.

[0016] Further, one end of the main box intermediate shaft is provided with a stepped mounting hole along the axis and the outer spline is processed, which is used for mounting the piston and spring connected with the friction disc.

[0017] Further, each of the concave positioning pins is made of 20Cr material, which has high hardness, high wear resistance and good toughness, and is suitable for high load and wear environment; the intermediate shaft gear set and the main box intermediate shaft are made of 8620 material, which has high strength, high toughness and excellent carburizing property, and is suitable for heavy load gears and shaft parts.

[0018] Compared with the prior art, the utility model has the advantages of:

[0019] 1. The intermediate shaft gear set of the heavy commercial vehicle transmission main box intermediate shaft assembly adopts interference fit, and a reinforcing ring is additionally arranged on the gear hub for further positioning, the material of the reinforcing ring can be selected as a material different from the gear and having small thermal deformation, so that the positioning precision and torque transmission capacity of the gear are effectively improved, the transmission capacity of the intermediate shaft is greatly improved, and the power density of the heavy commercial vehicle transmission is further improved.

[0020] 2. The heavy commercial vehicle transmission main box intermediate shaft assembly uses the positioning pin with the annular groove processed on the outer wall in the circumferential direction for positioning in the positioning groove, so that the positioning pin is prevented from being seriously deformed due to the creep of the contacting parts, the failure rate of the positioning pin is reduced, the main box intermediate shaft and the main box intermediate shaft transmission gear matched with the positioning pin are prevented from being damaged, the quality and service life of the parts are improved, and the product performance is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Fig. 1 is a structural schematic view of the heavy commercial vehicle transmission main box intermediate shaft assembly embodiment of the utility model;

[0022] Figure 2 Fig. 2 is an exploded structural schematic view of the heavy commercial vehicle transmission main box intermediate shaft assembly embodiment of the utility model;

[0023] Figure 3 Fig. 3 is a sectional structural schematic view of the heavy commercial vehicle transmission main box intermediate shaft assembly embodiment of the utility model;

[0024] Figure 4 Fig. 4 is a local enlarged structural schematic view of the area A. Figure 3 Fig. 5 is a local enlarged structural schematic view of the area B.

[0025] MARKS OF THE DRAWINGS:

[0026] 1-main box intermediate shaft double gear; 2-positioning pin; 3-main box intermediate shaft transmission gear; 4-main box intermediate shaft; 5-reinforcing ring. DETAILED DESCRIPTION

[0027] The utility model will be further described below in combination with the drawings and specific embodiments.

[0028] A heavy commercial vehicle transmission main box intermediate shaft assembly, the overall structure as shown in Figures 1-3 The main box intermediate shaft 4 includes an outer spline section, a connecting section, and a helical tooth section connected in sequence from one end to the other end in the axial direction; the radius R of the connecting section of the main box intermediate shaft 4 is 70.1 mm, and the main box intermediate shaft double gear 1 and the main box intermediate shaft transmission gear 3 are connected in sequence on the connecting section in an interference fit; the main box intermediate shaft double gear 1 is installed on one side of the connecting section close to the outer spline section, the main box intermediate shaft transmission gear 3 is installed on one side of the connecting section close to the helical tooth section, and the center hole inner diameters of the two gears are both 70 mm; a hub is arranged on one side of the main box intermediate shaft transmission gear 3 close to the main box intermediate shaft double gear 1, and a hub is arranged between the main box intermediate shaft double gears 1; positioning holes are radially formed on the hubs of the main box intermediate shaft double gear 1 and the main box intermediate shaft transmission gear 3;

[0029] Positioning blind holes are radially formed on the connecting section of the main box intermediate shaft 4 at positions corresponding to the two positioning holes; a reinforcing ring 5 is further connected in an interference fit on the hub of the main box intermediate shaft transmission gear 3, and a mounting hole is radially formed on the reinforcing ring 5 at a position corresponding to the positioning hole on the main box intermediate shaft transmission gear 3; one positioning pin 2 is assembled in the positioning hole of the main box intermediate shaft double gear 1 and the positioning blind hole on the connecting section of the main box intermediate shaft 4, and a groove formed in a circumferential direction on the outer wall of the positioning pin 2 corresponds to the joint of the connecting section of the main box intermediate shaft 4 and the main box intermediate shaft double gear 1; the other positioning pin 2 passes through the mounting hole on the reinforcing ring 5 and is assembled in the positioning hole of the main box intermediate shaft transmission gear 3 and the positioning blind hole on the connecting section of the main box intermediate shaft 4; similarly, an annular groove formed in a circumferential direction on the outer wall of the positioning pin 2 corresponds to the joint of the connecting section of the main box intermediate shaft 4 and the main box intermediate shaft transmission gear 3; the groove depth of the positioning pin 2 is 2 mm, and the groove width is 6 mm, that is, R1-R2=6 mm.

[0030] The main box intermediate shaft double gear 1, the main box intermediate shaft transmission gear 3, and the main box intermediate shaft 4 are all made of 8620 material; and the positioning pin 2 is made of 20Cr material. The 8620 material has high strength, high toughness, and excellent carburizing property, and is suitable for heavy load gears and shaft parts; the 20Cr material has high hardness, high wear resistance, and good toughness, and is suitable for high load and wear environments.

[0031] The specific assembly process of the utility model is as follows:

[0032] Firstly, the intermediate shaft transmission gear 3 in the main case is hot-mounted with the reinforcing ring 5 to make them interference fit; secondly, the combination of the intermediate shaft transmission gear 3 and the reinforcing ring 5 is hot-mounted with the intermediate shaft 4 in the main case to make the intermediate shaft transmission gear 3 and the intermediate shaft 4 in the main case interference fit; then, the double gear 1 of the intermediate shaft in the main case is hot-mounted with the intermediate shaft 4 in the main case to make them interference fit; finally, the two positioning pins 2 are respectively mounted into the positioning holes in the two gears and the positioning blind holes in the connecting section of the intermediate shaft in the main case to realize further axial positioning. This process can not only ensure that the outer wall of the positioning pin 2 does not directly contact with the hole wall of the combined surface of the part to realize accurate positioning, but also effectively prevent the deformation damage of the positioning pin caused by the creep of the part, thereby significantly improving the positioning reliability and reducing the possibility of failure.

[0033] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, not to limit them. For ordinary professional technicians in the art, the specific technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions protected by the present application.

Claims

1. A heavy-duty commercial vehicle transmission main case intermediate shaft assembly, comprising: The main box intermediate shaft (4) and the intermediate shaft gear set; The main box intermediate shaft (4) comprises an external spline section, a connecting section and a helical gear section connected in sequence from one end to the other end in the axial direction; The intermediate shaft gear set is installed on the connecting section of the main box intermediate shaft (4); It is characterized in that: The intermediate shaft gear set and the connecting section of the main box intermediate shaft (4) are in interference fit; A positioning hole is radially formed on the hub of each gear in the intermediate shaft gear set, and a positioning blind hole corresponding to each positioning hole is radially formed on the connecting section of the main box intermediate shaft (4); a plurality of positioning pins are respectively installed in each pair of corresponding positioning holes and positioning blind holes, further positioning and fastening the intermediate shaft gear set on the main box intermediate shaft (4); An annular groove is circumferentially formed on the outer wall of each positioning pin (2), and the position of the annular groove corresponds to the position of the joint of the connecting section of the main box intermediate shaft (4) and each gear in the intermediate shaft gear set; the distance between the upper edge of the annular groove and the axis of the main box intermediate shaft (4) is defined as R1, the distance between the lower edge of the annular groove and the axis of the main box intermediate shaft (4) is defined as R2, and the radius of the connecting section of the main box intermediate shaft (4) is defined as R, then R1>R>R2.

2. The main box intermediate shaft assembly of the heavy commercial vehicle transmission according to claim 1, characterized in that: R1, R and R2 satisfy the following relationship: (R1-R2) / 2=R-R2.

3. The main box intermediate shaft assembly of the heavy commercial vehicle transmission according to claim 1 or 2, characterized in that: The intermediate shaft gear set comprises a main box intermediate shaft double gear (1) and a main box intermediate shaft drive gear (3), the main box intermediate shaft double gear (1) is installed on one side of the connecting section close to the external spline section, and the main box intermediate shaft drive gear (3) is installed on one side of the connecting section close to the helical gear section; The side of the main box intermediate shaft drive gear (3) close to the main box intermediate shaft double gear (1) is provided with a hub, and the main box intermediate shaft double gear (1) is also provided with a hub; the hubs of the main box intermediate shaft drive gear (3) and the main box intermediate shaft double gear (1) are fixed on the connecting section through the positioning pins (2).

4. The main box intermediate shaft assembly of the heavy commercial vehicle transmission according to claim 3, characterized in that: A reinforcing ring (5) is sleeved on the hub of the main box intermediate shaft drive gear (3), and the two are in interference fit, which is used to improve the torque transmission capacity of the main box intermediate shaft drive gear (3); an installation hole is radially formed on the reinforcing ring (5) at a position corresponding to the positioning hole on the hub of the main box intermediate shaft drive gear (3), so that the positioning pin (2) can pass through the installation hole and be installed in the positioning hole on the intermediate shaft drive gear (3) and the corresponding positioning blind hole.

5. The main box intermediate shaft assembly of the heavy commercial vehicle transmission according to claim 1, characterized in that: A stepped installation hole is axially formed on one end of the main box intermediate shaft (4), which is used to install a piston and a spring connected with a friction disc.

6. The main box intermediate shaft assembly of the heavy commercial vehicle transmission according to claim 1, characterized in that: The annular groove on the positioning pin 2 has a groove depth of 2 mm and a groove width of 6 mm.

7. A heavy-duty commercial vehicle transmission main group countershaft assembly according to claim 1, characterized in that: Each of the positioning pins (2) is made of 20Cr material; the intermediate shaft gear set and the main group countershaft (4) are made of 8620 material.

Images