Large-transmission-ratio small-size speed reducer of electric power steering gear

Abstract

The large-transmission-ratio small-size speed reducer of the electric power steering gear comprises a driving motor, a worm, a worm gear, a planetary gear assembly, an output shaft and a shell assembly, the driving motor is connected with the worm through a coupler, and the worm gear is connected with the worm in a meshed mode; one end of a supporting shaft of the planetary gear assembly is rotationally connected with the shell assembly, the other end of the supporting shaft of the planetary gear assembly is rotationally connected with the output shaft, the first sun gear and the second sun gear are arranged on the two sides of the worm gear respectively and are coaxial with the worm gear, the first sun gear sleeves the supporting shaft and is fixedly connected with the shell assembly, and the second sun gear is in key connection with the output shaft; the multiple planet wheel sets are evenly distributed on the worm wheel in the circumferential direction in a rotating mode, each planet wheel set comprises two planet wheels, the two planet wheels are coaxially arranged on the two sides of the worm wheel and rotate synchronously, and the planet wheels on the two sides of the worm wheel are connected with the sun wheels on the same side in a meshed mode respectively. The worm and worm gear serves as the input of the planetary reducer, and the planetary reducer has the advantages of being large in transmission ratio and small in size.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of motor vehicle power drive steering gear design, concretely relates to a big transmission ratio small volume speed reducer of electric power steering gear. BACKGROUND

[0002] Electric power steering system as the representative of mechatronics, the combination of motor and electronic device, while meeting the driver's operation light and applicability, improve the grasp of road feeling, have a more positive improvement to the driving system of the automobile. The electric power steering system of the automobile is a power steering system directly relying on the motor to provide auxiliary torque, which is composed of an electronic control servo system based on a mechanical steering gear (for cars, mostly rack and pinion type). The system is mainly composed of sensors, controllers and actuators, and the energy source of the motor comes from the vehicle battery. The controller analyzes the signals of various sensors, issues control instructions according to certain control strategies and wheel states, delivers current to the motor when the vehicle is steering and returning, realizes power assistance and return control, improves the steering performance of the vehicle, assists the driver to complete the steering operation, and makes the steering easy, sensitive and stable.

[0003] At present, in the electric power steering system in China, there are heavy trucks and commercial new energy buses with large tonnage, which lack steering gears that can be better applied to heavy load, high power consumption and large steering power demand. UTILITY MODEL CONTENTS

[0004] To solve the above problems in the prior art, the utility model provides a big transmission ratio small volume speed reducer of electric power steering gear.

[0005] To achieve the above technical purposes, the utility model adopts the technical scheme of:

[0006] A big transmission ratio small volume speed reducer of electric power steering gear, comprising a driving motor, a worm, a worm wheel, a planetary gear assembly, an output shaft and a housing assembly, the housing assembly comprises a combined housing and a box cover, the worm, the worm wheel and the planetary gear assembly are arranged in the combined housing, and the box cover is connected to the combined housing; the driving motor is fixed outside the combined housing, and the output shaft penetrates through the box cover.

[0007] The driving motor is connected to the worm through a shaft coupling, and the worm wheel is connected to the worm.

[0008] The planetary gear assembly comprises a first sun gear, a second sun gear, a support shaft, a plurality of planetary gear sets, one end of the support shaft is rotationally connected with the housing assembly, the other end is rotationally connected with an output shaft, the first sun gear and the second sun gear are arranged on two sides of the worm gear and are coaxial with the worm gear, the first sun gear is sleeved on the support shaft and is fixedly connected with the housing assembly, and the second sun gear is keyed with the output shaft; the plurality of planetary gear sets are rotationally arranged on the worm gear in a circumferential direction, each planetary gear set comprises two planetary gears, the two planetary gears are coaxially arranged on two sides of the worm gear, and the two planetary gears rotate synchronously, and the planetary gears on two sides of the worm gear are respectively meshed with the sun gears on the same side.

[0009] Preferably, the planetary gear set is provided with 2-6 sets.

[0010] Preferably, the planetary gear set is provided with 3 sets.

[0011] Preferably, the worm is rotationally connected with the combined housing through a bearing assembly at two ends.

[0012] Preferably, a sealing gasket is arranged between the combined housing and the box cover and is fixedly connected through a bolt assembly.

[0013] Preferably, the driving motor is connected with the combined housing through a bolt assembly, and a sealing gasket is arranged between the driving motor and the combined housing.

[0014] The electric power steering gear has the advantages that:

[0015] The large-ratio small-size reducer of the electric power steering gear takes the worm and the worm gear as the input of the planetary carrier of the planetary reducer, the total transmission ratio can reach above 850, has the characteristics of large transmission ratio and small size, and is better adapted to steering and return-to-center use in the case of large output torque.

[0016] The worm and worm gear structure is adopted as the input of the planetary carrier of the planetary reducer, the large-ratio planetary reducer is obtained to reduce speed and increase torque. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the present application, and should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0018] Figure 1 is the overall schematic diagram of the large transmission ratio small volume speed reducer of the electric power steering gear of the utility model.

[0019] Figure 2 is the internal structure schematic diagram of the large transmission ratio small volume speed reducer of the electric power steering gear of the utility model Figure One .

[0020] Figure 3 is the internal structure schematic diagram of the large transmission ratio small volume speed reducer of the electric power steering gear of the utility model Figure Two .

[0021] Figure 4 is the front view of the large transmission ratio small volume speed reducer of the electric power steering gear of the utility model Figure One .

[0022] Figure 5 is Figure 4 the sectional view schematic diagram.

[0023] Reference signs: 1-drive motor, 2-worm, 3-worm wheel, 4-planetary gear assembly, 41-first sun gear, 42-second sun gear, 43-supporting shaft, 44-planetary gear, 5-output shaft, 61-combined housing, 62-box cover. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0025] A large transmission ratio small volume speed reducer of an electric power steering gear, such as Figures 1-5As shown, including driving motor 1, worm 2, worm gear 3, planetary gear assembly 4, output shaft 5 and housing assembly, the housing assembly includes combination housing 61 and box cover 62, worm 2, worm gear 3, planetary gear assembly 4 is arranged in combination housing 61, box cover 62 covers and connects the combination housing 61, the driving motor 1 is fixed outside the combination housing 61, the output shaft 5 passes out of the box cover 62;The driving motor 1 is connected with the worm 2 through the shaft coupling, the worm gear 3 is engaged with the worm 2;The planetary gear assembly 4 includes first sun gear 41, second sun gear 42, support shaft 43, a plurality of planetary gear sets, one end of the support shaft 43 is rotatably connected with the housing assembly 61, the other end is rotatably connected with the output shaft 5, the first sun gear 41 and the second sun gear 42 are arranged on both sides of the worm gear 3, and the first sun gear 41 is arranged on the support shaft 43 and is fixedly connected with the housing assembly 61, and the second sun gear 42 is connected with the output shaft 5;A plurality of planetary gear sets are circumferentially arranged on the worm gear 3, each planetary gear set includes two planetary gears 44, the two planetary gears 44 are coaxially arranged on both sides of the worm gear 3, and the two planetary gears 44 rotate synchronously, and the planetary gears 44 on both sides of the worm gear 3 are engaged with the sun gears on the same side.

[0026] Preferably, the planetary gear set is provided with 2-6 groups;More preferably, the planetary gear set is provided with 3 groups.

[0027] Further, the both ends of the worm 2 are rotatably connected with the combination housing 61 through bearing assemblies.

[0028] Preferably, a sealing pad is arranged between the combination housing 61 and the box cover 62 and is fixedly connected through a bolt assembly, the driving motor 1 is connected with the combination housing 61 through a bolt assembly, and a sealing pad is arranged between the driving motor 1 and the combination housing 61.

[0029] The large transmission ratio small size reducer of the electric power steering gear, the input torque is transmitted to the worm 2 and the worm gear 3 through the driving motor 1, the worm gear 3 is used as the planet carrier to transmit to the planetary gear set, the planetary gear set rotates under the action of the first sun gear 41, the torque is transmitted to the second sun gear 42, and the second sun gear 42 is transmitted to the output shaft 5, the worm gear is used as the planet carrier as the input of the planetary reducer, the total transmission ratio can reach more than 850, and the transmission ratio is large and the volume is small, so that the steering and returning to normal use when the output torque is large are better adapted.

[0030] The utility model discloses a worm and gear structure is used as the planetary reduction gear of planetary carrier input, obtains the planetary reduction gear of big transmission ratio to reduce speed and increase the moment. Simultaneously because small volume light weight, make the reducer in this scheme have more flexible arrangement mode, more suitable for commercial big torque vehicle, fill up the blank of electric power assisted steering gear reducer in this, also more fit in the use of commercial vehicle, green high efficiency also more promote the comfort degree of the operation feeling of driver in the driving, and the utility model discloses a worm and gear structure is used as the planetary reduction gear of planetary carrier input, obtains the planetary reduction gear of big transmission ratio to reduce speed and increase the moment.

[0031] Of course, the utility model can also have other various embodiments, without departing from the spirit and essence of the utility model, those skilled in the art can make various corresponding changes and deformation according to the utility model, but these corresponding changes and deformation all should belong to the protection scope of the claims of the utility model.

Claims

1. A large-ratio small-volume reducer for an electric power steering gear, characterized by: The application relates to a driving motor (1), a worm (2), a worm wheel (3), a planetary gear assembly (4), an output shaft (5) and a shell assembly, wherein the shell assembly comprises a combined shell (61) and a box cover (62), the worm (2), the worm wheel (3) and the planetary gear assembly (4) are arranged in the combined shell (61), the box cover (62) is connected to the combined shell (61), the driving motor (1) is fixed outside the combined shell (61), and the output shaft (5) penetrates through the box cover (62). The driving motor (1) is connected with the worm (2) through a shaft coupling, and the worm wheel (3) is connected with the worm (2) in a meshing mode. The planetary gear assembly (4) comprises a first sun gear (41), a second sun gear (42), a supporting shaft (43) and a plurality of planetary gear sets, one end of the supporting shaft (43) is rotationally connected with the combined shell (61), the other end is rotationally connected with the output shaft (5), the first sun gear (41) and the second sun gear (42) are arranged on the two sides of the worm wheel (3) and are coaxial with the worm wheel (3), the first sun gear (41) is sleeved on the supporting shaft (43) and is fixedly connected with the combined shell (61), the second sun gear (42) is connected with the output shaft (5) in a keying mode, the planetary gear sets are rotationally arranged on the worm wheel (3) in a circumferential distribution mode, each planetary gear set comprises two planetary gears (44), the two planetary gears (44) are coaxially arranged on the two sides of the worm wheel (3) and rotate synchronously, and the planetary gears (44) on the two sides of the worm wheel (3) are connected with the sun gears on the same side in a meshing mode.

2. An electric power assisted steering gear large reduction ratio small volume reduction gear according to claim 1 characterised in that: The planetary gear sets are 2-6 sets.

3. An electric power assisted steering gear large reduction ratio small volume reduction gear according to claim 2 characterised in that: The planetary gear sets are 3 sets.

4. An electric power assisted steering gear large reduction ratio small volume reduction gear according to claim 1 characterised in that: The worm (2) is rotationally connected with the combined shell (61) through bearing assemblies at two ends.

5. An electric power assisted steering gear large reduction ratio small volume reduction gear according to claim 1 characterised in that: Sealing pads are arranged between the combined shell (61) and the box cover (62) and are fixedly connected through bolt assemblies.

6. An electric power assisted steering gear large reduction ratio small volume reduction gear according to claim 1 characterised in that: The driving motor (1) is connected with the combined shell (61) through bolt assemblies, and sealing pads are arranged between the driving motor (1) and the combined shell (61).

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