Creep-resistant injection molding gear, EMB locking mechanism with creep-resistant injection molding gear and vehicle

Abstract

The invention discloses an injection molding gear with creep resistance, locking grooves or locking teeth are arranged on the injection molding gear, the injection molding gear is manufactured by adopting an injection molding process, an inner framework is arranged in the injection molding gear, and the inner framework is made of a metal material. According to the injection molding gear, the inner framework made of the metal material is arranged in the gear, so that the creep resistance of the locking gear can be effectively improved. The invention further discloses an EMB locking mechanism and a vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of braking systems. Specifically, the present invention relates to an injection-molded gear with anti-creep property, an EMB locking mechanism having the same, and a vehicle. Background Art

[0002] Existing electro-mechanical braking systems (EMBs) all have locking mechanisms. Among them, there is a structure that uses an electromagnet as a locking power device. By the extension and retraction of the locking head of the electromagnet, the power transmission is locked and unlocked, so as to realize the locking of the entire parking system. Among them, the locking groove or teeth cooperating with the locking head of the electromagnet are integrated on the gear. That is, when parking and locking, due to the existence of the parking clamping force, a large force will act on the contact surface between the gear and the locking head and remain for a long time with parking.

[0003] The EMB locking mechanism includes a locking gear cooperating with the electromagnet. The locking gear is a double gear. The problems existing in the double gear in the prior art are:

[0004] The double gear is provided with a locking groove. If the double gear is made of a metal material, there is no problem with the strength of the double gear, but there are problems of meshing noise between metal gears and impact noise generated during locking; if the double gear is made of a plastic material, the noise problem can be solved, but there is a risk of plastic deformation due to creep. This is because when parking and locking, due to the existence of the parking clamping force, a reverse acting force is maintained on the transmission route, and this reverse acting force will act on the locking mechanism module through the locking head structure and the push rod of the electromagnet. Similarly, there will be a long-term force between the locking head and the locking end surface in the locking groove of the double gear that remains with parking. When the double gear uses a plastic gear, due to the long-term action of this holding force on the plastic material, the double gear will creep, resulting in plastic deformation of the double gear. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides an injection-molded gear, aiming to improve the anti-creep performance.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: an injection-molded gear with anti-creep property, the injection-molded gear is provided with a locking groove or locking teeth, the injection-molded gear is made by an injection molding process and an inner skeleton is arranged inside the injection-molded gear, and the inner skeleton is made of a metal material.

[0007] The injection-molded gear is a double gear, which includes a large gear and a small gear. The locking groove or locking teeth are arranged on the large gear, and the inner skeleton is arranged inside the large gear.

[0008] The pinion gear and the inner framework are integrally formed.

[0009] The pinion gear and the inner framework are assembled and formed.

[0010] The pinion gear and the inner framework are press-fitted with interference or spline-connected.

[0011] The inner framework includes an inner ring and support bars that are connected to the inner ring and inserted into the inside of the large gear. A plurality of support bars are provided and all the support bars are evenly distributed circumferentially. The inner ring is connected to the pinion gear.

[0012] The inner framework further includes an outer ring that is connected to the support bars and located inside the large gear. The diameter of the outer ring is larger than the diameter of the inner ring.

[0013] Both ends of the support bar are respectively connected to the outer ring and the inner ring, and the outer ring and the inner ring are coaxially arranged.

[0014] A plurality of locking grooves are provided and all the locking grooves are evenly distributed circumferentially on the large gear. Each of the support bars is located between two adjacent locking grooves in the circumferential direction.

[0015] The pinion gear is made by powder metallurgy process.

[0016] The present invention also provides an EMB locking mechanism, including the injection-molded gear described above.

[0017] The present invention also provides a vehicle, including the EMB locking mechanism described above.

[0018] For the injection-molded gear of the present invention, by arranging an inner framework made of a metal material inside the gear, the anti-creep performance of the locking gear can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] This specification includes the following drawings, and the shown contents are respectively:

[0020] Figure 1 It is the front view of the large gear in Embodiment 1;

[0021] Figure 2 It is the structural schematic diagram of the pinion gear in Embodiment 1;

[0022] Figure 3 It is the structural schematic diagram of the inner framework in Embodiment 1;

[0023] Figure 4 It is the structural schematic diagram of the large gear in Embodiment 1;

[0024] Figure 5 It is the assembly schematic diagram of the inner framework and the pinion gear in Embodiment 2;

[0025] Figure 6is a schematic diagram of the assembly of the inner frame and the pinion gear in the third embodiment;

[0026] Figure 7 is a schematic diagram of the structure of the large gear in the third embodiment;

[0027] Figure 8 It is a front view of the large gear in the third embodiment;

[0028] Figure 9 is an exploded schematic diagram of the locking mechanism;

[0029] Figure 10 It is an overall view of the lock head and gear status when parking;

[0030] Figure 11 This is the front view of the lock head and gear status when parking;

[0031] Figure 12 It is the MGU cutaway view;

[0032] Figure 13 This is a simplified diagram of the positions of the gears when locked;

[0033] Figure 14 It is a structural schematic diagram of an injection-molded double gear in the prior art;

[0034] Figure 15 It is another structural schematic diagram of the injection-molded double gear of the prior art;

[0035] Figure 16 It is a schematic diagram of the structure of a small gear in an injection-molded double gear in the prior art;

[0036] Figure 17 It is a structural schematic diagram of a large gear in an injection-molded double gear in the prior art;

[0037] Figure 18 It is a front view of a large gear in an injection-molded double gear in the prior art;

[0038] Markings in the figure are: 1. injection molded double gears; 2. double gears I; 2a. large gear; 2b. small gear; 3. double gears II; 3a. large gear; 3b. small gear and skeleton assembly structure; 3b1. inner skeleton; 3b2. small gear; 4. double gears III; 4a. large gear; 4b. small gear and skeleton assembly structure; 4b1. inner skeleton; 4b2. small gear; 5. double gears; 5a. locking end face; 5b. locking groove; 5c. non-locking end face; 6. circuit board; 7. ECU housing; 8. ECU housing cover; 9. shaft pin; 10. electromagnet; 10a. locking head; 11. MGU housing; 11a. cavity; 12. motor; 13. motor gear; 14. output gear. DETAILED DESCRIPTION

[0039] The following is a further detailed description of the specific implementation manners of the present invention with reference to the accompanying drawings through the description of embodiments, aiming to help those skilled in the art have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention, and facilitate its implementation.

[0040] The present invention provides an injection-molded gear with anti-creep property. A locking groove or locking teeth are provided on the injection-molded gear. The injection-molded gear is made by injection molding process and an inner skeleton is arranged inside the injection-molded gear, and the inner skeleton is made of metal material.

[0041] The present invention also provides an EMB locking mechanism, including an injection-molded gear (i.e., a locking gear). Locking grooves or locking teeth are provided on the locking gear. The locking gear is made by injection molding process and an inner skeleton is arranged inside the locking gear, and the inner skeleton is made of metal material.

[0042] Specifically, the locking gear is a double gear, which includes a large gear and a small gear. Locking grooves are provided on the large gear. An inner skeleton is arranged inside the large gear, and the inner skeleton is made of metal material. By arranging an inner skeleton made of metal material inside the large gear, the anti-creep property of the double gear can be effectively improved.

[0043] As Figure 13 shown, the electromagnet is used as the power device of the EMB locking mechanism. The extension and retraction of the electromagnet push rod are used to cooperate with the locking grooves provided on the large gear 4a of the double gear, so as to realize the locking of the entire transmission system. As Figure 13 shown in the schematic diagram, the motor gear 13 is characterized by fast speed and small torque, and the output gear 14 is characterized by slow speed and large torque. Since the rotation speed of the motor gear 13 is relatively fast, if the large gear 4a of the double gear meshed with it is made of metal material, noise will be generated when the metal gears mesh and rotate at high speed. At the same time, noise will also be generated when the locking push rod head impacts the large gear of the double gear when the locking mechanism performs locking. Considering the characteristics of the locking mechanism, when parking, the teeth of the large gear 4a of the double gear and the motor gear 13 are not stressed during locking, and they are also at the level with relatively small stress. It is the spoke of the large gear 4a of the double gear that is stressed for a long time during parking locking. Therefore, the large gear 4a of the double gear can be made of plastic material instead. The small gear 4b2 of the double gear is made of metal material. In this way, the meshing of the plastic gear and the metal gear can solve the noise problem, and the noise generated by the impact of the locking head on the metal gear when the locking mechanism performs locking will also be reduced. However, if the large gear of the double gear is made of plastic gear, the problem is that due to the existence of the parking structure, the spoke of the double gear is stressed for a long time during locking, and long-term stress will cause creep of the plastic spoke. Therefore, when injecting the large gear of the double gear, a metal skeleton structure is designed inside, which can effectively solve the possible risk of creep.

[0044] As Figures 9 to 12As shown in the figure, the MGU includes an EMB locking mechanism, an MGU housing 11, an ECU cover 8, an ECU housing 7, a circuit board 6, and a motor 12. The ECU housing 7 is fixedly arranged on the MGU housing 11, the ECU cover 8 is fixedly arranged on the ECU housing 7, and the electromagnet 10 is arranged inside the MGU housing 11. The motor gear and the motor 12 are axially arranged. The motor 12 is arranged in a cavity provided on the MGU housing 11. The double gear 5 is arranged on the pin 9, and the pin 9 is press-fitted into the MGU housing 11 with interference. The electromagnet 10 is arranged in another cavity 11a provided on the MGU housing 11, and the circuit board 6 is arranged inside the ECU housing 7. The EMB locking mechanism includes an electromagnet 10 and a multi-stage gear transmission mechanism. The locking head of the electromagnet 10 is set to be embedded in the locking groove 5b provided on the locking gear in the locking state. By the extension and retraction of the locking head of the electromagnet 10 to cooperate with and unlock the locking groove 5b on the locking gear, the parking locking function of the entire EMB brake is realized.

[0045] As Figure 10 and Figure 11 shown in the figure, a locking end face 5a and a non-locking end face 5c are provided in the locking groove 5b. The locking end face 5a and the non-locking end face 5c are the inner wall surfaces at the opposite ends in the length direction of the locking groove 5b. The locking end face 5a is used to contact the surface of the locking head in the locking state. The non-locking end face 5c is used to push the locking head out of the locking groove 5b during the rotation of the double gear 5. The non-locking end face 5c is a plane inclined in the locking groove 5b. There is an angle between the non-locking end face 5c and the axis of the double gear 5, and this angle is an acute angle. The moving direction of the locking head is parallel to the axis of the double gear 5. A first contact surface in contact with the non-locking end face 5c is provided on the locking head. This first contact surface is an inclined plane. There is an angle between the first contact surface and the moving direction of the locking head, and this angle is an acute angle. The inclined angles of the first contact surface and the non-locking end face 5c are the same. The locking end face 5a is a plane parallel to the axis of the double gear 5. A second contact surface in contact with the locking end face 5a is provided on the locking head. The second contact surface is a plane parallel to the moving direction of the locking head. In the locking state, the second contact surface fits with the locking end face 5a, and the locking head plays a circumferential limiting role on the double gear 5 to achieve locking. A plurality of locking grooves 5b are provided, and all the locking grooves 5b are evenly distributed circumferentially on the gear with the axis of the double gear 5 as the center line. In the locking state, the locking head is inserted into one of the locking grooves 5b.

[0046] As Figure 13As shown in the figure, the multi-stage gear transmission mechanism includes a first-stage transmission mechanism and a second-stage transmission mechanism. The driving gear of the first-stage transmission mechanism is connected to the motor 12, and the motor 12 provides driving force. A locking groove 5b is provided on the driven gear (i.e., the large gear 4a) of the first-stage transmission mechanism. The driving gear (i.e., the motor gear 13) of the first-stage transmission mechanism meshes with the driven gear. The driven gear of the first-stage transmission mechanism is fixedly connected to the driving gear (i.e., the small gear 4b2) of the second-stage transmission mechanism to form a double gear 5. The driven gear of the second-stage transmission mechanism is the output gear 14. The driven gear of the first-stage transmission mechanism meshes with the driving gear of the second-stage transmission mechanism, and the output gear 14 outputs power.

[0047] When parking and locking, the ECU (Electronic Control Unit) transmits the locking command to the electromagnet 10 through the bus bar. The electromagnet 10 is powered on, and the push rod and the moving iron core of the electromagnet 10 extend out. The locking head 10a extends into the locking groove 5b of the gear for parking and locking, as shown in the schematic Figure 11 As shown, the locking head 10a completes the cooperation with the locking end face 5a, restricting the rotation of the double gear 5 for parking and locking, thereby realizing the locking function; when releasing the parking, the ECU transmits the release command to the electromagnet 10 through the bus bar. The electromagnet 10 is reversely powered on, and the locking head 10a of the electromagnet 10 retracts. The locking head 10a of the electromagnet 10 retracts outside the locking groove 5b, and the locking head 10a of the electromagnet 10 is decoupled from the locking groove 5b of the double gear 5. The rotation of the double gear 5 is not restricted by the locking head 10a, thereby realizing the release of the parking lock.

[0048] As Figure 11 shown, when parking, the locking head of the electromagnet contacts the locking end face 5a. Due to the existence of the parking clamping force, the double gear 5 has a tendency to rotate clockwise. Thus, the gear has a holding force on the locking head in the clockwise direction, and the holding force remains during parking. If the gear structure is entirely injection-molded, there is a risk of creep and plastic deformation of the gear under long-term force retention. However, if a metal inner skeleton is designed in the injection-molded gear structure, the parking holding force will act on the large skeleton, and through the supporting effect of the metal large skeleton, the risk of gear creep can be effectively eliminated.

[0049] Embodiment 1

[0050] In this embodiment, as Figures 1 to 4As shown, the diameter of the large gear 3a is larger than the diameter of the small gear 3b2. The material of the large gear 3a is plastic. The large gear 3a adopts the coating process, and the small gear 3b2 adopts the powder metallurgy process. The spokes of the large gear 3a are provided with locking grooves. The coating process is injection molding on the inner skeleton 3b1. The distance of the inner skeleton 3b1 in the circumferential direction of the gear exceeds the distance of the locking groove in the circumferential direction of the gear, ensuring that the locking groove can act on the inner skeleton 3b1 under the maintenance of long-term parking force. The inner skeleton 3b1 is made of a material with high strength such as metal, and can meet the requirements of the injection molding process.

[0051] In this embodiment, if Figures 1 to 4 As shown, the material of the inner skeleton 3b1 is metal, the inner skeleton 3b1 is formed by a stamping process, the material of the pinion 3b2 is powder metallurgy, and the pinion 3b2 and the inner skeleton 3b1 are assembled together to form a pinion and skeleton assembly structure 3b.

[0052] like Figure 1 and Figure 3 As shown, the inner skeleton 3b1 includes an inner ring and a support bar connected to the inner ring and inserted into the large gear 3a. The inner ring is a circular ring structure and the inner ring and the large gear 3a are coaxially arranged. The inner ring is located at the center of the large gear 3a. A plurality of support bars are provided and all support bars are evenly distributed along the circumferential direction with the axis of the inner ring as the center line. The inner ring is fixedly connected to the pinion 3b2 and the two are coaxial. A plurality of locking grooves are provided and all locking grooves are evenly distributed along the circumferential direction on the large gear 3a. Each support bar is located between two adjacent locking grooves in the circumferential direction.

[0053] In this embodiment, eight locking grooves are provided on the large gear 3a, and eight support bars are also provided. All support bars are radially distributed inside the large gear 3a, which can effectively improve the anti-creep performance of the duplex gear.

[0054] The double gears of this embodiment have the following advantages:

[0055] 1. Reduce noise: The plastic gear structure can reduce weight and reduce gear transmission noise;

[0056] 2. Can reduce the impact sound: the locking groove is integrally injection molded, and the impact sound with the electromagnet locking head is reduced;

[0057] 3. Can increase the spoke strength: The large frame is made of metal, which can effectively increase the anti-creep performance of injection molded gears.

[0058] Embodiment 2

[0059] In this embodiment, if Figure 5As shown, the materials of the pinion gear 3b2 and the inner framework 3b1 are both powder metallurgy. The pinion gear 3b2 and the inner framework 3b1 are integrally formed by powder metallurgy process. The forming process here is not unique. Then, based on the pinion gear and framework assembly structure 3b formed by the pinion gear 3b2 and the inner framework 3b1, injection molding is carried out to form the large gear, and finally an anti-creep double gear is formed.

[0060] Embodiment III

[0061] The main difference between this embodiment and Embodiment I and Embodiment II lies in the different structure of the inner framework. In this embodiment, as Figure 6 and Figure 8 shown, the inner framework 4b1 further includes an outer ring connected to the support bar and located inside the large gear 4a. The outer ring is a circular ring structure, and the diameter of the outer ring is larger than that of the inner ring. The two ends in the length direction of the support bar are respectively fixedly connected to the outer ring and the inner ring, and the outer ring and the inner ring are coaxially arranged. Adding the outer ring is for two reasons. On the one hand, it is to increase the strength of the inner framework. Because with the addition of the outer ring, the supporting effect can be increased. Without the outer ring, when the inner framework is stressed, it is equivalent to a cantilever structure. In this case, when stressed, the long support bar is prone to deformation. On the other hand, for the part of the outer ring, near the outer gear position of the large gear of the double gear, the gear is formed by injection molding process. After injection molding, the tooth profile will produce asymmetric shrinkage deformation due to the locking groove being close to one side. Therefore, setting an inner framework with an outer ring can make the large gear tooth profile produce uniform shrinkage deformation after injection molding, and such a design can make the injection molded tooth profile better.

[0062] The present invention has been described exemplarily in combination with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention; or without improvement, the above concept and technical solution of the present invention are directly applied to other occasions, they are all within the protection scope of the present invention.

Claims

1. An injection-molded gear with creep resistance, having a locking groove or locking teeth provided on the injection-molded gear, Characterized in that: The injection-molded gear is made by an injection molding process and an inner skeleton is provided inside the injection-molded gear, and the inner skeleton is made of a metal material.

2. The injection-molded gear according to claim 1, Characterized in that: The injection-molded gear is a double gear, which includes a large gear and a small gear. The locking groove or locking teeth are provided on the large gear, and the inner skeleton is provided inside the large gear.

3. The injection-molded gear according to claim 2, Characterized in that: The small gear and the inner skeleton are integrally formed.

4. The injection-molded gear according to claim 2, Characterized in that: The small gear and the inner skeleton are assembled and formed.

5. The injection-molded gear according to claim 2, Characterized in that: The small gear and the inner skeleton are press-fitted with interference or spline-connected.

6. The injection-molded gear according to any one of claims 1 to 5, Characterized in that: The inner skeleton includes an inner ring and support bars connected to the inner ring and inserted into the inside of the large gear. A plurality of support bars are provided and all the support bars are evenly distributed in the circumferential direction, and the inner ring is connected to the small gear.

7. The injection-molded gear according to claim 6, Characterized in that: The inner skeleton further includes an outer ring connected to the support bars and located inside the large gear, and the diameter of the outer ring is larger than the diameter of the inner ring.

8. The injection-molded gear according to claim 7, Characterized in that: Both ends of the support bar are respectively connected to the outer ring and the inner ring, and the outer ring and the inner ring are coaxially arranged.

9. The injection-molded gear according to claim 6, Characterized in that: A plurality of locking grooves are provided, and all the locking grooves are evenly distributed in the circumferential direction on the large gear, and each of the support bars is located between two adjacent locking grooves in the circumferential direction.

10. The injection-molded gear according to any one of claims 1 to 5, Characterized in that: The small gear is made by a powder metallurgy process.

11. An EMB locking mechanism, Characterized in that: It includes the injection-molded gear according to any one of claims 1 to 10.

12. A vehicle, Characterized in that: It includes the EMB locking mechanism according to claim 11.

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