A hydraulic retarder for reducing no-load losses and its control method

Abstract

This invention discloses a hydraulic retarder for reducing no-load losses, comprising: a stator, a rotor, and hydraulic fluid disposed inside a housing; a rotor shaft fixedly connected to the rotor; a high-gear and a low-gear on the rotor shaft, both loosely fitted on the rotor shaft; a low-gear and a high-gear on the output shaft fixedly fitted on the gearbox output shaft, respectively meshing with the low-gear and high-gear on the rotor shaft; a sliding sleeve axially movable, fitted on the rotor shaft, selectively meshing with either the high-gear or low-gear on the rotor shaft; a shift fork connected to the sliding sleeve for driving its movement; a cylinder including a first piston and a second piston, forming multiple working cylinders; an air source selectively connected to the multiple working cylinders; and the piston rod of the first piston selectively contacting the second piston, the piston rod of the second piston being connected to the shift fork. This invention features reduced no-load losses and increased braking power.

Description

Technical Field

[0001] This invention relates to the field of hydraulic retarder technology, and more specifically, to a hydraulic retarder and its control method for reducing no-load losses. Background Technology

[0002] A hydraulic retarder is an auxiliary braking device. In situations requiring prolonged or intensive braking, such as long downhill slopes, normal braking can lead to decreased braking efficiency or even brake failure due to brake overheating. Using a hydraulic retarder for auxiliary braking can effectively reduce brake fade.

[0003] In most cars equipped with hydraulic retarders, because the rotor is connected to the retarder shaft, even when the hydraulic retarder is unloaded, the air in the retarder's working chamber flows back to the oil reservoir. However, a large amount of gas remains in the working chamber. Driven by the rotor, this gas generates a braking force similar to that of hydraulic fluid in the working chamber, resulting in high no-load losses for the retarder. At this time, the rotor is still connected to the output shaft through gears, transmitting the braking force and reacting on the output shaft, causing power loss. This can easily lead to problems such as insufficient vehicle power and overall vehicle power loss. Therefore, ensuring that there are no losses in the hydraulic retarder when the car is unloaded is an urgent problem to be solved.

[0004] In a patented working chamber structure of a hydraulic retarder with separable stator and rotor, a pair of cooperating inner and outer slant splines are used to achieve axial movement of the rotor by means of the axial force generated by the slant splines. When the hydraulic retarder is in an unloaded state, it increases the distance between the rotor and the stator, thereby reducing idling losses.

[0005] In a patent for a rotor-separable hydraulic retarder, when the brake is released, the driving force is removed, and the meshing gears separate from the rotor under the action of the separation spring, returning to the left positioning position. The rotor no longer rotates with the retarder shaft, and it runs unloaded, which can reduce the wear caused by the hydraulic retarder.

[0006] In current research on reducing losses in hydraulic retarders under no-load conditions, most studies cannot completely stop the rotor and instead rely on increasing the distance between the rotor and stator to reduce losses. However, only when the rotor is completely stopped can the low loss of the hydraulic retarder under no-load conditions be truly achieved.

[0007] Moreover, when the vehicle is traveling at low speed, the output shaft speed is low, which in turn results in a low speed transmitted to the retarder rotor. Consequently, the hydraulic retarder has insufficient braking power, reduced braking efficiency, and cannot generate enough braking force for auxiliary braking. Summary of the Invention

[0008] The purpose of this invention is to design and develop a hydraulic retarder that reduces no-load losses. It can selectively interrupt or connect the power transmission between the output shaft of the vehicle's transmission system and the retarder, thereby reducing the no-load losses of the retarder.

[0009] This invention also designs and develops a control method for a hydraulic retarder that reduces no-load losses. Through two modes, it ensures that the retarder has higher braking efficiency and working performance in both low-speed and high-speed conditions.

[0010] The technical solution provided by this invention is as follows:

[0011] A hydraulic retarder for reducing no-load losses includes:

[0012] The housing contains the stator, rotor, and oil.

[0013] A rotor shaft, which is fixedly connected to the rotor;

[0014] The high-speed gear of the rotor shaft is loosely fitted on the rotor shaft;

[0015] The low-gear of the rotor shaft is loosely fitted on the rotor shaft;

[0016] The output shaft low gear is fixedly sleeved on the gearbox output shaft, and the output shaft low gear meshes with the rotor shaft low gear.

[0017] The output shaft high gear is fixedly sleeved on the gearbox output shaft, and the output shaft high gear meshes with the rotor shaft high gear;

[0018] A sliding sleeve, which is axially movable and sleeved on the rotor shaft, and the sliding sleeve can selectively mesh with the high gear or the low gear of the rotor shaft;

[0019] A fork, which is connected to the sliding sleeve, is used to drive the sliding sleeve to move;

[0020] A cylinder, comprising a first piston and a second piston, such that the cylinder is sequentially divided into a first working cylinder, a second working cylinder and a third working cylinder;

[0021] An air source, which can be selectively connected to the first working cylinder, the second working cylinder, and / or the third working cylinder;

[0022] The piston rod of the first piston may selectively contact the second piston, and the piston rod of the second piston is connected to the shift fork.

[0023] Preferably, it also includes:

[0024] An oil storage chamber is fixed to the outside of the housing;

[0025] An oil inlet pipe is disposed between the oil storage chamber and the housing;

[0026] A one-way valve is disposed between the oil reservoir and the housing;

[0027] An intake and exhaust valve assembly, the outlet end of which is connected to the oil storage chamber, and the intake end of which is connected to an air source;

[0028] The outlet of the intake and exhaust valve assembly and the inlet of the oil inlet pipeline are respectively located on both sides of the oil storage chamber.

[0029] Preferably, it also includes:

[0030] A spring steel ball, which is mounted on the shift fork, is used for the self-locking of the shift fork.

[0031] Preferably, it also includes:

[0032] The first and second position three-way valve is located between the air source and the first working cylinder;

[0033] The second two-position three-way valve is located between the air source and the second working cylinder;

[0034] The third two-position three-way valve is located between the air source and the third working cylinder.

[0035] Preferably, it also includes:

[0036] A position sensor, which is mounted on the housing, is used to detect the position of the sliding sleeve.

[0037] Preferably, it also includes:

[0038] The retarder electronic control unit is connected to the CAN bus, position sensor, first two-position three-way valve, second two-position three-way valve, third two-position three-way valve and intake / exhaust valve group for the transmission of commands and signals.

[0039] A control method for a hydraulic retarder that reduces no-load losses, using the aforementioned hydraulic retarder that reduces no-load losses, includes the following steps:

[0040] Step 1: Collect vehicle speed signals and synchronizer position signals;

[0041] Step 2: When the vehicle does not require auxiliary braking, the transmission output shaft is not engaged with the rotor shaft;

[0042] When the vehicle requires assisted braking, the retarder electronic control unit is activated, and the intake and exhaust valve groups inject air into the reservoir:

[0043] When the vehicle is in low gear, the cylinder displacement reaches the low gear position, the cylinder pushes the shift fork to move, and the sliding sleeve meshes with the low gear gear of the rotor shaft.

[0044] When the vehicle is in high gear, the cylinder displacement reaches the high gear position, the cylinder pushes the shift fork to move, and the sliding sleeve meshes with the high gear gear of the rotor shaft;

[0045] The low-speed gear condition is v < 45 km / h, and the high-speed gear condition is v ≥ 45 km / h;

[0046] In the formula, v is the speed of the vehicle.

[0047] Preferably, the cylinder displacement is in the neutral position when the vehicle does not require auxiliary braking.

[0048] Preferably, the specific adjustment process for the cylinder displacement to reach the low-speed position is as follows:

[0049] The second two-position three-way valve is open, and the third two-position three-way valve is closed.

[0050] The specific adjustment process for the cylinder displacement to reach the high-speed gear position is as follows:

[0051] The first two-position three-way valve is closed, the second two-position three-way valve is closed, and the third two-position three-way valve is open.

[0052] Preferably, the cylinder displacement being in the neutral position specifically includes the cylinder displacement initially being in the neutral position, the cylinder displacement returning to the neutral position from the low-speed position, or the cylinder displacement returning to the neutral position from the high-speed position. The specific adjustment process for the cylinder displacement returning to the neutral position from the low-speed position is as follows:

[0053] The first two-position three-way valve is open, the second two-position three-way valve is closed, and the third two-position three-way valve is open;

[0054] The specific adjustment process for the cylinder to return from the high-speed position to the neutral position is as follows:

[0055] The first two-position three-way valve is open, the second two-position three-way valve is closed, and the third two-position three-way valve is closed.

[0056] The beneficial effects of this invention are as follows:

[0057] (1) The present invention designs and develops a hydraulic retarder to reduce no-load loss. By setting a sliding sleeve, the power transmission between the output shaft and the retarder is interrupted, which greatly reduces the no-load loss when the retarder is not working and reduces the fuel consumption of the whole vehicle.

[0058] (2) The present invention designs and develops a control method for a hydraulic retarder that reduces no-load loss. The retarder is set with two modes. When the vehicle speed is low, the braking power of the hydraulic retarder can be effectively improved, thus improving the working performance of the retarder.

[0059] (3) The present invention designs and develops a control method for a hydraulic retarder that reduces no-load loss. The output shaft speed is identified by the output shaft speed sensor through the output shaft speed signal transmitted by the CAN bus. The electronic control unit judges the driver's needs and selects the best retarder gear and air intake to ensure the best braking effect of the retarder. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the height adjustment device of the hydraulic retarder for reducing no-load loss according to the present invention.

[0061] Figure 2 This is a schematic diagram of the cylinder described in this invention. Detailed Implementation

[0062] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0063] like Figure 1 As shown, the hydraulic retarder for reducing no-load losses provided by the present invention includes:

[0064] Housing 110, rotor 121, stator 122, rotor shaft 131, rotor shaft high gear 132, rotor shaft low gear 133, sliding sleeve 134, transmission system output shaft (gearbox output shaft) 141, output shaft high gear 142, output shaft low gear 143, air source 151, first two-position three-way valve 152, second two-position three-way valve 153, third two-position three-way valve 154, cylinder 160, shift fork 170, spring steel ball 171, oil reservoir 181, oil inlet pipe 182, one-way valve 183, intake and exhaust valve assembly 184, retarder electronic control unit 191, and position sensor 192.

[0065] The housing 110 contains a rotor 121 and a stator 122. The stator is fixed to the housing 110, and the rotor 121 is rotatably disposed on one side of the stator 122. The rotor shaft 131 is fixedly connected to the rotor 121.

[0066] The rotor shaft 131 is loosely fitted with a high-gear 132 and a low-gear 133.

[0067] A high-gear 142 and a low-gear 143 are fixedly connected to the output shaft 141 of the transmission system. The high-gear 142 meshes with the high-gear 132 of the rotor shaft, and the low-gear 143 meshes with the low-gear 133 of the rotor shaft.

[0068] The sliding sleeve 134 is sleeved on the rotor shaft 131 via an inner spline, allowing the sliding sleeve 134 to move axially on the rotor shaft 131. Gear structures are provided at both ends of the outer side of the sliding sleeve 134. The gear structures can be selectively engaged with the high gear 132 or the low gear 133 of the rotor shaft, and are in neutral when the retarder is not working.

[0069] like Figure 2 As shown, the cylinder 160 includes a first piston 161 and a second piston 162. The piston rod of the first piston 161 can selectively contact the second piston 162, that is, the first piston 161 and the second piston 162 are not fixed. The first piston 161 and the cylinder wall form the first working cylinder, the first piston 161 and the second piston 162 form the second working cylinder, and the second piston 162 and the cylinder wall form the third working cylinder.

[0070] The first two-position three-way valve 152 is disposed between the air source 151 and the first working cylinder, the second two-position three-way valve 153 is disposed between the air source 151 and the second working cylinder, and the third two-position three-way valve 154 is disposed between the air source 151 and the third working cylinder. The first two-position three-way valve 152, the second two-position three-way valve 153 and the third two-position three-way valve 154 control the intake and exhaust of the cylinder 160.

[0071] The shift fork 170 is connected to the second piston 162 and the sliding sleeve 134. It is driven by the cylinder 160, which in turn controls the movement of the sliding sleeve 134. A spring steel ball 171 is installed on the shift fork 170 to achieve self-locking of the shift fork 170.

[0072] The gas source 151 is a vehicle-mounted gas source.

[0073] The oil storage chamber 181 is fixed to the outside of the housing 110, and retarder oil is filled in the cavity of the oil storage chamber 181. The oil inlet pipe 182 is arranged between the oil storage chamber 181 and the housing 110. The one-way valve 183 is arranged between the oil storage chamber 181 and the housing 110. The outlet end of the air intake and exhaust valve assembly 184 is connected to the oil storage chamber 181, and the inlet end is connected to the air source 151. The outlet end of the air intake and exhaust valve assembly 184 and the inlet of the oil inlet pipe 182 are respectively arranged on both sides of the oil storage chamber 181. The pressure of oil intake and exhaust is achieved by the air intake and exhaust valve assembly 184. The retarder oil is pressed into the housing 110 through the oil inlet pipe 182 by the air intake, and the retarder oil is discharged back to the oil storage chamber 181 through the one-way valve 183 by the exhaust.

[0074] A position sensor 192 is provided on the outside of the housing 110 to detect the position of the sliding sleeve 134; the retarder electronic control unit 191 receives and processes the speed signals from the position sensor 192 and the CAN bus, and controls the opening and closing of the first two-position three-way valve 152, the second two-position three-way valve 153 and the third two-position three-way valve 154, as well as the working status and pressure of the intake and exhaust valve group 184.

[0075] This invention relates to a hydraulic retarder designed and developed to reduce idling losses. By setting a sliding sleeve to interrupt the power transmission between the output shaft and the retarder, the idling losses when the retarder is not working are significantly reduced, thereby lowering the overall vehicle fuel consumption.

[0076] The present invention also provides a control method for a hydraulic retarder that reduces no-load losses, the method comprising the following steps:

[0077] Step 1: Acquire vehicle speed signals and synchronizer position signals (sliding sleeve position signals) via CAN bus and position sensors;

[0078] Step 2: When the vehicle is in motion and the retarder is not required for auxiliary braking, the high gear and low gear of the rotor shaft rotate freely under the drive of the high gear and low gear of the output shaft. The cylinder displacement is in the middle position, and the sliding sleeve is in the middle position. It does not mesh with the high gear or low gear of the rotor shaft, so it does not transmit torque and does not generate additional no-load loss.

[0079] When the vehicle requires assisted braking, the driver activates the retarder's assisted braking function, which in turn activates the retarder's electronic control unit (ECU). The ECU sends a working command to the intake and exhaust valve assembly, which then injects air into the top of the reservoir, allowing retarder oil to enter the housing. Simultaneously, the ECU determines the vehicle's current driving status based on the speed signal transmitted via the CAN bus and sends corresponding working commands to the solenoid valve assembly.

[0080] If v < 45km / h, the vehicle is in low gear. The retarder electronic control unit controls the second two-position three-way valve to open while keeping the third two-position three-way valve closed. The cylinder displacement reaches the low gear position, and the cylinder pushes the shift fork to move, so that the sliding sleeve and the low gear gear of the rotor shaft mesh with each other. The shift fork achieves self-locking through the spring steel ball. The rotor shaft has a large speed ratio relative to the output shaft. The rotor starts to rotate and agitate the working oil, thereby generating a braking torque on the output shaft. The retarder enters the working state.

[0081] When v≥45km / h, the vehicle is in high gear. The retarder electronic control unit controls the first two-position three-way valve to close, the second two-position three-way valve to close, and the third two-position three-way valve to open. The cylinder displacement reaches the high gear position, the cylinder pushes the shift fork to move, so that the sliding sleeve meshes with the high gear gear of the rotor shaft. The shift fork is self-locked by the spring steel ball. The rotor starts to rotate and agitate the working oil, thereby generating a braking torque on the output shaft, and the retarder enters the working state.

[0082] In the formula, v is the speed of the vehicle;

[0083] When the auxiliary braking is completed, when the cylinder displacement returns from the low speed position to the middle position, the retarder electronic control unit controls the first two-position three-way valve to open, the second two-position three-way valve to close, and the third two-position three-way valve to open.

[0084] When the cylinder returns from the high-speed position to the neutral position, the retarder electronic control unit controls the first two-position three-way valve to open, the second two-position three-way valve to close, and the third two-position three-way valve to close.

[0085] This invention presents a control method for a hydraulic retarder that reduces no-load losses. The retarder is equipped with two modes, which can effectively improve the braking power of the hydraulic retarder and enhance its performance when the vehicle speed is low. The output shaft speed is identified by the output shaft speed sensor through the CAN bus signal, and the electronic control unit determines the driver's needs to select the optimal retarder mode and air intake to ensure the best braking effect of the retarder.

[0086] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A hydraulic retarder for reducing no-load losses, characterized in that, include: The housing contains the stator, rotor, and oil. A rotor shaft, which is fixedly connected to the rotor; The high-speed gear of the rotor shaft is loosely fitted on the rotor shaft; The low-gear of the rotor shaft is loosely fitted on the rotor shaft; The output shaft low gear is fixedly sleeved on the gearbox output shaft, and the output shaft low gear meshes with the rotor shaft low gear. The output shaft high gear is fixedly sleeved on the gearbox output shaft, and the output shaft high gear meshes with the rotor shaft high gear; A sliding sleeve, which is axially movable and sleeved on the rotor shaft, and the sliding sleeve can selectively mesh with the high gear or the low gear of the rotor shaft; A fork, which is connected to the sliding sleeve, is used to drive the sliding sleeve to move; A cylinder, comprising a first piston and a second piston, such that the cylinder is sequentially divided into a first working cylinder, a second working cylinder and a third working cylinder; An air source, which can be selectively connected to the first working cylinder, the second working cylinder, and / or the third working cylinder; The piston rod of the first piston may selectively contact the second piston, and the piston rod of the second piston is connected to the shift fork.

2. The hydraulic retarder for reducing no-load losses as described in claim 1, characterized in that, Also includes: An oil storage chamber is fixed to the outside of the housing; An oil inlet pipe is disposed between the oil storage chamber and the housing; A one-way valve is disposed between the oil reservoir and the housing; An intake and exhaust valve assembly, the outlet end of which is connected to the oil storage chamber, and the intake end of which is connected to an air source; The outlet of the intake and exhaust valve assembly and the inlet of the oil inlet pipeline are respectively located on both sides of the oil storage chamber.

3. The hydraulic retarder for reducing no-load losses as described in claim 2, characterized in that, Also includes: A spring steel ball, which is mounted on the shift fork, is used for the self-locking of the shift fork.

4. The hydraulic retarder for reducing no-load losses as described in claim 3, characterized in that, Also includes: The first and second position three-way valve is located between the air source and the first working cylinder; The second two-position three-way valve is located between the air source and the second working cylinder; The third two-position three-way valve is located between the air source and the third working cylinder.

5. The hydraulic retarder for reducing no-load losses as described in claim 4, characterized in that, Also includes: A position sensor, which is mounted on the housing, is used to detect the position of the sliding sleeve.

6. The hydraulic retarder for reducing no-load losses as described in claim 5, characterized in that, Also includes: The retarder electronic control unit is connected to the vehicle's CAN bus, the position sensor, the first two-position three-way valve, the second two-position three-way valve, the third two-position three-way valve, and the intake and exhaust valve group for the transmission of commands and signals.

7. A control method for a hydraulic retarder to reduce no-load losses, using the hydraulic retarder for reducing no-load losses as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Collect vehicle speed signals and synchronizer position signals; Step 2: When the vehicle does not require auxiliary braking, the transmission output shaft is not engaged with the rotor shaft; When the vehicle requires assisted braking, the retarder electronic control unit is activated, and the intake and exhaust valve groups inject air into the reservoir: When the vehicle is in low gear, the cylinder displacement reaches the low gear position, the cylinder pushes the shift fork to move, and the sliding sleeve meshes with the low gear gear of the rotor shaft. When the vehicle is in high gear, the cylinder displacement reaches the high gear position, the cylinder pushes the shift fork to move, and the sliding sleeve meshes with the high gear gear of the rotor shaft; The low-speed gear condition is v < 45 km / h, and the high-speed gear condition is v ≥ 45 km / h; In the formula, v is the speed of the vehicle.

8. The control method for reducing no-load losses of a hydraulic retarder as described in claim 7, characterized in that, When the vehicle does not require auxiliary braking, the cylinder displacement is in the neutral position.

9. The control method for reducing no-load losses of a hydraulic retarder as described in claim 8, characterized in that, The specific adjustment process for the cylinder displacement to reach the low-speed position is as follows: The second two-position three-way valve is open, and the third two-position three-way valve is closed. The specific adjustment process for the cylinder displacement to reach the high-speed gear position is as follows: The first two-position three-way valve is closed, the second two-position three-way valve is closed, and the third two-position three-way valve is open.

10. The control method for reducing no-load losses of a hydraulic retarder as described in claim 9, characterized in that, The cylinder displacement being in the neutral position specifically includes the cylinder displacement initially being in the neutral position, the cylinder displacement returning to the neutral position from the low-speed position, or the cylinder displacement returning to the neutral position from the high-speed position. The specific adjustment process for the cylinder displacement returning to the neutral position from the low-speed position is as follows: The first two-position three-way valve is open, the second two-position three-way valve is closed, and the third two-position three-way valve is open; The specific adjustment process for the cylinder to return from the high-speed position to the neutral position is as follows: The first two-position three-way valve is open, the second two-position three-way valve is closed, and the third two-position three-way valve is closed.

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