Hydraulically controlled limited-slip differential

Abstract

This invention discloses a hydraulically controlled limited-slip differential, belonging to the field of engineering machinery technology. It mainly includes a differential torque device connected to a drive axle housing. The differential torque device includes a cylinder housing with an oil port A. The drive axle housing has an oil port B that mates with oil port A. Oil ports A and B are sealed together by a sealing pin. The connection between the cylinder housing and the drive axle housing via the sealing pin simplifies the oil supply structure and improves installation and maintenance. The oil port A of the cylinder housing is connected to the drive axle housing via a sealing pin, facilitating assembly and maintenance. Furthermore, anti-rotation measures are added to eliminate the risks of wear and oil leakage caused by component rotation due to inertia and torque. This invention is primarily used in engineering machinery.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery technology, and more specifically, relates to a hydraulically controlled limited-slip differential. Background Technology

[0002] To ensure good maneuverability of construction machinery during cornering, a differential is required. However, this results in the same torque on both tires, preventing full utilization of ground traction. Therefore, to improve the power performance of construction machinery, a limited-slip differential or differential lock is needed. Currently, the most common limited-slip differential is the friction plate clutch type, which uses hydraulic pressure to push a piston in a cylinder to press against the friction plates, thereby limiting the differential speed and improving vehicle power performance.

[0003] Existing limited-slip differentials have largely similar friction plate structures, but their cylinder structures vary, resulting in differences in manufacturing processes and performance. For example, as shown in utility model patent CN208734834U, the brake housing and piston form a cylinder assembly. Hydraulic oil is injected through an oil port on the brake housing, causing the piston to generate thrust. The piston pushes the thrust bearing, thrust sleeve, and thrust actuator lever, which in turn act on the brake and friction plates. The frictional torque between the friction plates can limit or prevent differential speed, thus achieving the effect of limited slip or differential lock. However, this structure requires an external oil port on external parts such as the axle housing to supply oil to the cylinder. This external port must be connected to the oil port on the cylinder housing through casting, machining, and assembly. If the cylinder's design and structure are poor, it can be difficult for the oil port on the cylinder housing to connect with the external oil port on the axle housing. The oil port on the brake housing is located inside the axle housing, requiring a specialized structure to connect it to the outside, leading to a complex limited-slip differential structure.

[0004] Secondly, continuing to use the friction plates when they are worn to their limit will lead to unpredictable failures. Since the friction plates are inside the differential, the wear condition cannot be predicted or measured from the outside. There is also no friction plate wear indicator mechanism in the existing differentials. Inspection requires a major disassembly of the differential, which is time-consuming and laborious. At the same time, there are no anti-rotation measures between the cylinder piston and the parts that transmit thrust. The relative rotation between them will also cause wear, oil leakage and other failures. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a hydraulically controlled limited-slip differential, wherein the oil port A of the cylinder housing is connected to the drive axle housing through a sealing pin, which is convenient for assembly and maintenance. At the same time, anti-rotation measures are added to eliminate the risks of wear and oil leakage caused by the rotation of parts due to inertia and torque.

[0006] The hydraulically controlled limited-slip differential includes a torque differential device connected to the drive axle housing. The torque differential device includes a cylinder housing with an oil port A. The drive axle housing has an oil port B that mates with oil port A. Oil ports A and B are sealed together by a sealing pin. The connection to the drive axle housing via the sealing pin simplifies the cylinder oil supply structure and improves installation and maintenance performance.

[0007] Preferably, the cylinder housing is provided with a positioning device to facilitate the alignment of oil port A and oil port B. The positioning device is fixedly connected to the cylinder housing and to the drive axle housing via fasteners. The positioning device is integrated with the cylinder housing for easy installation and ensures that oil port A and oil port B are automatically aligned after the cylinder housing and drive axle housing are installed.

[0008] Preferably, the differential torque device is connected to the differential, the differential includes a differential housing, a half-shaft gear is provided inside the differential housing, the differential torque device includes a differential torque housing, the differential torque housing is connected to the differential housing, a friction plate assembly is provided between the differential housing and the half-shaft gear, the driving friction plate of the friction plate assembly is connected to the half-shaft gear, the driven friction plate of the friction plate assembly is connected to the differential torque housing, a half-shaft connected to the half-shaft gear is provided inside the differential torque housing, a sleeve is sleeved on the half-shaft, a pressure plate that cooperates with the friction plate assembly is provided at one end of the sleeve, and a hydraulic cylinder piston is provided at the other end of the sleeve through a thrust bearing, the outer end face of the hydraulic cylinder piston is cooperated with oil port A.

[0009] Preferably, a return spring is provided on the outer side of the sleeve. One end of the return spring is connected to the differential torque housing, and the other end of the return spring engages with a boss on the sleeve. The return spring allows the pressure plate and the cylinder piston to automatically return to their original positions, reducing frictional wear of the friction plate assembly.

[0010] Preferably, the piston of the oil cylinder is provided with two or more limit pins, and there is a gap between two adjacent limit pins. The oil cylinder housing is provided with a locking bolt, which passes through the gap.

[0011] Preferably, the sleeve is provided with a limiting mechanism, and the sleeve is connected to the pressure plate through the limiting mechanism.

[0012] Preferably, the limiting mechanism is a spline, and the sleeve is connected to the pressure plate via the spline.

[0013] Preferably, the limiting mechanism is a pin, with one end of the pin embedded in the pressure plate and the other end embedded in the sleeve.

[0014] Preferably, a second gap is provided between the friction plate assembly and the differential torque housing, and oil passages are provided on both sides of the second gap.

[0015] Preferably, the drive axle housing is provided with a wear indicator mechanism, which includes a slider and a sliding pin. The slider is provided with a slide table that cooperates with the sliding pin. The sliding pin is provided with a positioning table and an elastic device one. At least two fixing pins pass through the slider. An elastic device two is provided at the end of the fixing pin near the friction plate assembly. The slider cooperates with the cylinder piston.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. The present invention adds an oil port B on the drive axle housing corresponding to the oil port A on the cylinder housing, and connects them with a sealing pin, avoiding the installation method of adding an extra connecting pipe to connect the oil port in the prior art, and simplifying the oil supply structure of the cylinder; at the same time, a positioning device is added to the cylinder housing, which makes it easier to connect to the drive axle housing through the positioning device, improves the installation and maintenance performance of the limited slip differential, and has low cost.

[0018] 2. A limit pin and a locking bolt are added to the cylinder piston to ensure that the cylinder piston can only move axially and cannot rotate around the central axis of the cylinder housing; a limit mechanism is added between the pressure plate and the sleeve to prevent rotation between the pressure plate and the sleeve due to inertia and the torque transmitted by the thrust bearing; through the above anti-rotation measures, the risks of wear and oil leakage caused by the rotation of parts due to inertia and torque are eliminated.

[0019] 3. A wear indicator mechanism is added. When the friction pad wears to the specified value, an electronic or mechanical indicator can automatically sound an alarm, making it more convenient to use.

[0020] 4. A second gap is added between the friction plate assembly and the differential torque housing, and oil passages are designed on both sides of the second gap to make it easier for lubricating oil to enter the friction plate assembly and facilitate the discharge of friction plate debris. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram showing the connection between the drive axle housing and the cylinder housing.

[0023] Figure 3 This is a schematic diagram of the wear indicator mechanism;

[0024] Figure 4 This is a reference diagram showing the usage status of the wear indicator mechanism;

[0025] Figure 5 This is a schematic diagram of the structure of gap two and the oil passage.

[0026] In the diagram, 1. Differential; 101. Differential housing; 102. Half-shaft gear; 2. Differential torque device; 201. Differential torque housing; 202. Friction plate assembly; 203. Retaining ring; 204. First pin; 205. Pressure plate; 206. Limiting mechanism; 207. Sleeve; 208. Return spring; 209. Locking bolt; 210. Limiting pin; 211. Hydraulic cylinder piston; 212. Hydraulic cylinder housing; 213. Thrust bearing; 214. Oil port A; 215. Positioning device; 216. Clearance II; 217. Oil passage; 3. Wear indicator mechanism; 301. Slider; 302. Slide table; 303. Sliding pin; 304. Positioning table; 305. Elastic device I; 306. Fixing pin; 307. Elastic device II; 308. Compression nut; 4. Drive axle housing. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings:

[0028] Example 1: As Figure 1 As shown, the hydraulically controlled limited-slip differential includes a differential torque device 2, which is connected to the drive axle housing 4. The differential torque device 2 includes a cylinder housing 212, with an oil port A214 on the cylinder housing 212 and an oil port B401 on the drive axle housing 4 that mates with the oil port A214. The oil ports A214 and B401 are sealed together by a sealing pin 402. In this embodiment, the oil port B401 corresponding to the oil port A214 is directly machined at the bottom of the drive axle housing 4, and the oil ports A214 and B401 are sealed together by the sealing pin 402, which greatly simplifies the oil supply structure of the cylinder and makes installation convenient. The sealing pin 402 can be removed from the outside of the drive axle housing 4 for easy inspection and replacement.

[0029] Example 2: Figure 2 As shown, the cylinder housing 212 is provided with a positioning device 215 to facilitate the alignment of oil ports A214 and B401. The positioning device 215 is fixedly connected to the cylinder housing 212 and to the drive axle housing 4 via fasteners; otherwise, it is the same as in Embodiment 1. In this embodiment, the positioning device 215 is a bearing seat, which is welded to the cylinder housing 212 as a whole and fixed to the drive axle housing 4 by bolts. The bearing seat is positioned to facilitate the alignment of oil ports A214 and B401, making the cylinder oil supply structure easy to maintain. Furthermore, in terms of achieving universality between limited-slip differentials and ordinary differentials, a general bearing seat can be used to replace the cylinder housing 212, saving materials and reducing production costs.

[0030] Example 3: Figure 1As shown, the differential torque device 2 is connected to the differential 1. The differential 1 includes a differential housing 101, and a half-shaft gear 102 is provided inside the differential housing 101. The differential torque device 2 includes a differential torque housing 201, which is bolted to the differential housing 101. A friction plate assembly 202 is provided between the differential housing 101 and the half-shaft gear 102. The driving friction plate of the friction plate assembly 202 is connected to the half-shaft gear 102, and the driven friction plate of the friction plate assembly 202 is connected to the half-shaft gear 102. The friction plate is connected to the differential torque housing 201 via a first pin 204 or bolts. The differential torque housing 201 contains a half shaft connected to the half shaft gear 102. A sleeve 207 is sleeved on the half shaft. One end of the sleeve 207 is provided with a pressure plate 205 that cooperates with the friction plate assembly 202. A retaining ring 203 is provided on the sleeve 207. The other end of the sleeve 207 is provided with a hydraulic cylinder piston 211 via a thrust bearing 213. The outer end face of the hydraulic cylinder piston 211 cooperates with the oil port A214.

[0031] A return spring 208 is provided on the outside of the sleeve 207. One end of the return spring 208 is connected to the differential torque housing 201, and the other end of the return spring 208 is engaged with the boss on the sleeve 207.

[0032] The piston 211 of the hydraulic cylinder is provided with two or more limit pins 210, and there is a gap between two adjacent limit pins 210. The cylinder housing 212 is provided with a locking bolt 209, which passes through the gap.

[0033] The sleeve 207 is provided with a limiting mechanism 206, and the sleeve 207 is connected to the pressure plate 205 through the limiting mechanism 206.

[0034] The limiting mechanism 206 is splined, and the sleeve 207 is connected to the pressure plate 205 via the spline. The limiting mechanism 206 can prevent the sleeve 207 and the pressure plate 205 from rotating relative to each other.

[0035] like Figure 5 As shown, a second gap 216 is provided between the friction plate assembly 202 and the differential torque housing 201, and oil passages 217 are provided on both sides of the second gap 216. This structure makes it easier for lubricating oil to enter the cavity where the friction plate assembly 202 is located, which is beneficial for heat dissipation of the friction plates and facilitates the removal of friction plate debris.

[0036] The drive axle housing 4 is provided with a wear indicator mechanism 3, which includes a slider 301 and a sliding pin 303. The slider 301 is provided with a slide table 302 that cooperates with the sliding pin 303. The sliding pin 303 is provided with a positioning table 304 and an elastic device 305. At least two fixing pins 306 pass through the slider 301. An elastic device 307 is provided at one end of the fixing pin 306 near the friction plate assembly 202. The slider 301 cooperates with the oil cylinder piston 211. Other aspects are the same as in Embodiment 2.

[0037] like Figure 3 and Figure 4As shown, during installation, the wear indicator mechanism 3 has one end of the fixing pin 306 near the friction plate assembly 202 connected to the drive axle housing 4, and the other end of the fixing pin 306 connected to the cylinder housing 212. The slider 301 can slide on the fixing pin 306. The bottom of the sliding pin 303 abuts against the slide table 302 of the slider 301. The top of the sliding pin 303 is pressed by the clamping nut 308. The upper end of the elastic device 305 abuts against the clamping nut 308. The clamping nut 308 is connected to an electronic or mechanical indicator.

[0038] Example 4: The limiting mechanism 206 is a pin, with one end embedded in the pressure plate 205 and the other end embedded in the sleeve 207; otherwise, it is the same as in Example 3. The pressure plate 205 is connected to the differential torque housing 7 by the pin. This structure can prevent the pressure plate 205 and the sleeve 207 from rotating due to inertia and the torque transmitted by the thrust bearing 213.

[0039] When using this invention, as Figure 1 As shown, hydraulic oil enters the cylinder oil chamber through oil port B401, sealing pin 402 and oil port A214 and is kept at a certain pressure, pushing the cylinder piston 211 to move to the left. The cylinder piston 211 pushes the thrust bearing 213 and sleeve 207, and finally applies the cylinder pressure to the pressure plate 205. The pressure plate 205 presses the friction plate assembly 202. The driven friction plate in the friction plate assembly 202 is connected to the differential torque housing 201 through pin 204. The driving friction plate in the friction plate assembly 202 is connected to the half-shaft gear 102. Therefore, for the half-shaft gear 102 and the differential torque housing 201 to have relative movement (i.e., generate differential speed), it is necessary to overcome the frictional resistance between the friction plates, so as to achieve the purpose of limiting differential speed and increasing power. When the hydraulic oil pressure in the cylinder is released, the sleeve 207, thrust bearing 213 and cylinder piston 211 return to their original positions under the action of return spring 208. The sleeve 207 is equipped with a retaining ring 203. When the sleeve 207 returns to its original position, the retaining ring 203 will drive the pressure plate 205 to return to its original position, so that there is sufficient clearance between the friction plates and the ineffective friction is reduced.

[0040] like Figure 4 As shown, when the friction plate assembly 202 wears to a certain extent, the cylinder piston 211 begins to push the slider 301 to the left. When the movement exceeds the contact length between the sliding pin 303 and the slider 301, the sliding pin 303 falls under the action of the elastic device 307, triggering the indicator connected to the sliding pin 303 and issuing an alarm signal to replace the friction plate. After replacing the friction plate, the sliding pin 303 is lifted upwards, and the slider 301 returns to its original position under the action of the two elastic devices 307 on the left. This structure can accurately remind the friction plate that it has reached its wear limit, avoiding malfunctions caused by excessive wear.

[0041] like Figure 1As shown, the cylinder piston 211 is equipped with two limit pins 210, and the locking bolt 209 passes through the gap between the two limit pins 210. The locking bolt 209 is fixed to the cylinder housing 212. Therefore, the cylinder piston 211 can only move axially and cannot rotate around the central axis of the cylinder housing 212. This structure can reduce the risk of cylinder oil leakage.

Claims

1. A hydraulically controlled limited-slip differential, comprising a differential torque device (2), the differential torque device (2) being connected to a drive axle housing (4), the differential torque device (2) comprising a cylinder housing (212), the cylinder housing (212) being provided with an oil port A (214), characterized in that: The drive axle housing (4) is provided with an oil port B (401) that mates with oil port A (214), and oil port A (214) and oil port B (401) are sealed together by a sealing pin (402); The differential torque device (2) is connected to the differential (1). The differential (1) includes a differential housing (101), and a half-shaft gear (102) is provided inside the differential housing (101). The differential torque device (2) includes a differential torque housing (201), which is connected to the differential housing (101). A friction plate assembly (202) is provided between the differential housing (101) and the half-shaft gear (102). The driving friction plate of the friction plate assembly (202) interacts with the half-shaft gear (102). The driven friction plate of the friction plate assembly (202) is connected to the differential torque housing (201). The differential torque housing (201) is provided with a half shaft connected to the half shaft gear (102). A sleeve (207) is sleeved on the half shaft. One end of the sleeve (207) is provided with a pressure plate (205) that cooperates with the friction plate assembly (202). The other end of the sleeve (207) is provided with a hydraulic cylinder piston (211) through a thrust bearing (213). The outer end face of the hydraulic cylinder piston (211) cooperates with the oil port A (214). The drive axle housing (4) is provided with a wear indicator mechanism (3), which includes a slider (301) and a sliding pin (303). The slider (301) is provided with a slide table (302) that cooperates with the sliding pin (303). The sliding pin (303) is provided with a positioning table (304) and an elastic device (305). At least two fixing pins (306) pass through the slider (301). An elastic device (307) is provided at one end of the fixing pin (306) near the friction plate assembly (202). The slider (301) cooperates with the cylinder piston (211). When the friction plate assembly (202) wears a certain amount, the cylinder piston (211) begins to push the slider (301) to move to the left. When the movement exceeds the contact length between the sliding pin (303) and the slider (301), the sliding pin (303) falls under the action of the second elastic device (307), triggering the indicator connected to the sliding pin (303) to issue an alarm signal to replace the friction plate. After replacing the friction plate, the sliding pin (303) is lifted upwards, and the slider (301) returns to its original position under the action of the two second elastic devices (307) on the left. When in use, hydraulic oil enters the cylinder oil chamber through oil port B (401), sealing pin (402) and oil port A (214) and maintains a certain pressure, pushing the cylinder piston (211) to move to the left. The cylinder piston (211) pushes the thrust bearing (213) and sleeve (207) to apply the cylinder pressure to the pressure plate (205), and the pressure plate (205) presses the friction plate assembly (202). When the hydraulic oil pressure in the cylinder is released, the sleeve (207), thrust bearing (213) and cylinder piston (211) return to their original positions under the action of return spring (208). The sleeve (207) is equipped with a retaining ring (203). When the sleeve (207) returns to its original position, the retaining ring (203) will drive the pressure plate (205) to return to its original position.

2. The hydraulically controlled limited-slip differential according to claim 1, characterized in that: The cylinder housing (212) is provided with a positioning device (215) to facilitate the correspondence between oil port A (214) and oil port B (401). The positioning device (215) is fixedly connected to the cylinder housing (212) and is fixedly connected to the drive axle housing (4) by fasteners.

3. The hydraulically controlled limited-slip differential according to claim 2, characterized in that: The sleeve (207) is provided with a return spring (208) on the outside. One end of the return spring (208) is connected to the differential torque housing (201), and the other end of the return spring (208) is engaged with the boss on the sleeve (207).

4. The hydraulically controlled limited-slip differential according to claim 3, characterized in that: The piston (211) of the oil cylinder is provided with two or more limit pins (210), and there is a gap between two adjacent limit pins (210). The cylinder housing (212) is provided with a locking bolt (209), and the locking bolt (209) passes through the gap.

5. The hydraulically controlled limited-slip differential according to claim 4, characterized in that: The sleeve (207) is provided with a limiting mechanism (206), and the sleeve (207) is connected to the pressure plate (205) through the limiting mechanism (206).

6. The hydraulically controlled limited-slip differential according to claim 5, characterized in that: The limiting mechanism (206) is a spline, and the sleeve (207) is connected to the pressure plate (205) via the spline.

7. The hydraulically controlled limited-slip differential according to claim 5, characterized in that: The limiting mechanism (206) is a pin, with one end of the pin embedded in the pressure plate (205) and the other end of the pin embedded in the sleeve (207).

8. The hydraulically controlled limited-slip differential according to claim 5, characterized in that: A second gap (216) is provided between the friction plate assembly (202) and the differential torque housing (201), and oil passages (217) are provided on both sides of the second gap (216).

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