Double-piston negative pressure gear engaging device for power takeoff

Abstract

The utility model discloses a double-piston negative pressure gear engaging device for a power takeoff, which comprises a power takeoff body, the power takeoff body comprises a power takeoff shell, the front side of the power takeoff shell is provided with a cylinder body, and the front side of the cylinder body is provided with a cylinder cover; a piston shaft is further included. The piston shaft comprises a first piston, a piston shaft middle section and a piston shaft front section which are coaxially arranged and integrally formed. The piston shaft middle section is installed on the cylinder body and can reciprocate in the axial direction. The front section of the piston shaft is coaxially sleeved with a second piston through a check ring. A first piston cavity is formed between the power takeoff shell and the cylinder body, and the first piston is located in the first piston cavity. A first piston cavity between the first piston and the power takeoff shell is a first vacuum cavity, and a first piston cavity between the first piston and the cylinder body is a first atmosphere cavity. The device adopts a double-piston structure, the stress area is increased by adding one piston, the diameter of the piston can be reduced by one third under the condition of the same pressure difference, the space of a power takeoff is saved, and the adaptability of a vehicle chassis is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to gearbox technical field relates to the power takeoff, concretely relates to a double piston negative pressure gear hanging device for power takeoff. BACKGROUND

[0002] The space of medium and light vehicle chassis is limited, generally no gas source is equipped with air tank, and the conventional pneumatic gear hanging power takeoff cannot be used.

[0003] In addition, the conventional vacuum negative pressure gear hanging power takeoff adopts single piston structure, because the engine vacuum negative pressure is much smaller than the air pressure of vehicle air tank, considering the gear hanging of power takeoff and spring return speed, the piston diameter usually needs to be designed larger, thereby limiting the structural arrangement of power takeoff. SUMMARY

[0004] In view of the deficiencies in the prior art, the utility model aims at providing a double piston negative pressure gear hanging device for power takeoff to solve the technical problem that the structural arrangement of power takeoff needs to be further improved when the medium and light vehicle uses the pneumatic gear hanging power takeoff.

[0005] In order to solve the above technical problem, the utility model adopts the following technical scheme to realize it:

[0006] A double piston negative pressure gear hanging device for power takeoff, comprising a power takeoff body, the power takeoff body comprising a power takeoff shell, a cylinder body is installed on the front side of the power takeoff shell, and a cylinder cover is installed on the front side of the cylinder body; further comprising a piston shaft.

[0007] The piston shaft comprises a coaxially arranged integrally formed first piston, a piston shaft middle segment and a piston shaft front segment, the piston shaft middle segment is installed on the cylinder body and can reciprocate in the axial direction, and the piston shaft front segment coaxially sleeves a second piston through a stop ring.

[0008] The first piston cavity is between the power takeoff shell and the cylinder body, and the first piston is located in the first piston cavity; the first piston cavity between the first piston and the power takeoff shell is the first vacuum cavity, and the first piston cavity between the first piston and the cylinder body is the first atmospheric cavity.

[0009] The second piston cavity is between the cylinder body and the cylinder cover, and the second piston is located in the second piston cavity; the second piston cavity between the second piston and the cylinder body is the second vacuum cavity, and the second piston cavity between the second piston and the cylinder cover is the second atmospheric cavity.

[0010] The power takeoff shell is provided with a vacuum interface communicating with the first vacuum cavity, and a vacuum channel is further formed in the piston shaft, which is used for communicating the first vacuum cavity and the second vacuum cavity.

[0011] The cylinder body is provided with a first atmosphere venting port communicating with the first atmosphere cavity.

[0012] The utility model also has the following technical features:

[0013] Specifically, an annular pressure equalizing groove is formed in the front end surface of the first piston.

[0014] Specifically, a shift fork shaft is mounted on the power takeoff housing, the front end of the shift fork shaft is in contact with the rear end of the first piston, the front end of the shift fork shaft is provided with a vacuum gap, and the first vacuum cavity is in communication with the vacuum channel through the vacuum gap.

[0015] Specifically, a first vent valve is arranged at the first atmosphere venting port.

[0016] A second vent valve is arranged at the second atmosphere venting port.

[0017] Specifically, the power takeoff body further comprises a gear shifting fork, and the gear shifting fork is coaxially sleeved on the shift fork shaft.

[0018] The utility model further comprises a compression spring, the compression spring is coaxially sleeved on the shift fork shaft, and the compression spring is located at the rear end of the gear shifting fork.

[0019] The utility model further comprises a gear shifting sleeve, and the gear shifting sleeve can reciprocate along the axial direction under the driving of the gear shifting fork.

[0020] Specifically, a first sealing ring is arranged between the shift fork shaft and the power takeoff housing.

[0021] A second sealing ring is arranged between the power takeoff housing and the first piston.

[0022] A third sealing ring is arranged between the cylinder body and the middle section of the piston shaft.

[0023] A fourth sealing ring is arranged between the cylinder body and the second piston.

[0024] Compared with the prior art, the utility model has the following beneficial technical effects:

[0025] (I) The device adopts a double-piston structure, the force receiving area is increased by adding one piston, the piston diameter can be reduced by one third under the condition of the same pressure difference, the power takeoff space is effectively saved, and the adaptability of the vehicle chassis is improved.

[0026] (II) The device of the utility model uses the vacuum negative pressure generated by the engine of the vehicle in the working process as the vacuum negative pressure source, so that the power take-off realizes the gear engagement operation; when the power take-off needs to work, the piston moves under the pressure difference generated by the atmospheric pressure and the vacuum negative pressure, so that the power take-off realizes the gear engagement operation. The vacuum negative pressure gear engagement power take-off does not need to be equipped with the air tank gas source of the vehicle, and can realize the working of the power take-off, and expands the application range of the chassis of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is the structure schematic view of the double-piston negative pressure gear engagement device for the power take-off in the utility model.

[0028] The meanings of various reference numerals in the drawing are as follows: 1-power take-off body, 2-cylinder body, 3-cylinder cover, 4-piston shaft, 5-stop ring, 6-second piston, 7-first vacuum cavity, 8-first atmospheric cavity, 9-second vacuum cavity, 10-second atmospheric cavity, 11-vacuum interface, 12-first atmospheric air vent, 13-second atmospheric air vent, 14-vacuum gap, 15-first air vent valve, 16-second air vent valve, 17-first sealing ring, 18-second sealing ring, 19-third sealing ring, 20-fourth sealing ring.

[0029] 101-power take-off shell, 102-shifting fork shaft, 103-gear engagement shifting fork, 104-compression spring, 105-gear engagement sliding sleeve.

[0030] 401-first piston, 402-piston shaft middle section, 403-piston shaft front section, 404-vacuum channel, 405-annular pressure equalizing groove.

[0031] The specific content of the utility model is further explained and described in detail in combination with the embodiments. DETAILED DESCRIPTION

[0032] It should be noted that all the equipment and parts in the utility model, such as without special description, all adopt the known equipment and parts in the prior art. For example, the power take-off body 1 adopts the known power take-off body, the stop ring 5 adopts the known stop ring, the shifting fork shaft 102 adopts the known shifting fork shaft, the gear engagement shifting fork 103 adopts the known gear engagement shifting fork, and the gear engagement sliding sleeve 105 adopts the known gear engagement sliding sleeve.

[0033] The technical idea of the utility model is that the engine of the vehicle generates the vacuum negative pressure in the working process and stores it in the energy storage chamber. The engine energy storage chamber is connected with the power take-off vacuum interface through the air pipe, and the electromagnetic valve controls the on-off. One side of the power take-off piston is communicated with the atmosphere, and the other side is the vacuum negative pressure. The piston drives the shifting fork to execute the gear engagement operation of the power take-off under the action of the pressure difference.

[0034] Following the above technical solution, the following are specific embodiments of this utility model. It should be noted that this utility model is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solution of this application fall within the protection scope of this utility model.

[0035] Example:

[0036] This embodiment provides a dual-piston negative pressure shifting device for a power take-off unit, such as... Figure 1 As shown, it includes a power take-off body 1, which includes a power take-off housing 101, a cylinder block 2 mounted on the front side of the power take-off housing 101, and a cylinder head 3 mounted on the front side of the cylinder block 2; it also includes a piston shaft 4.

[0037] like Figure 1 As shown, the piston shaft 4 includes a first piston 401, a piston shaft middle section 402, and a piston shaft front section 403, which are coaxially arranged and integrally formed. The piston shaft middle section 402 is mounted on the cylinder body 2 and can reciprocate axially. The piston shaft front section 403 is coaxially fitted with a second piston 6 through a stop ring 5.

[0038] like Figure 1 As shown, the first piston chamber is located between the power take-off housing 101 and the cylinder 2, and the first piston 401 is located in the first piston chamber; the first piston chamber between the first piston 401 and the power take-off housing 101 is the first vacuum chamber 7, and the first piston chamber between the first piston 401 and the cylinder 2 is the first atmospheric chamber 8.

[0039] like Figure 1 As shown, the second piston chamber is located between the cylinder block 2 and the cylinder head 3, and the second piston 6 is located in the second piston chamber; the second piston chamber between the second piston 6 and the cylinder block 2 is the second vacuum chamber 9, and the second piston chamber between the second piston 6 and the cylinder head 3 is the second atmospheric chamber 10.

[0040] like Figure 1 As shown, the power take-off housing 101 is provided with a vacuum interface 11 that connects to the first vacuum chamber 7, and a vacuum channel 404 is also provided inside the piston shaft 4. The vacuum channel 404 is used to connect the first vacuum chamber 7 and the second vacuum chamber 9.

[0041] like Figure 1 As shown, the cylinder block 2 is provided with a first atmospheric vent 12 that connects to the first atmospheric chamber 8; the cylinder head 3 is provided with a second atmospheric vent 13 that connects to the second atmospheric chamber 10.

[0042] As a preferred embodiment of this invention, such as Figure 1 As shown, an annular pressure equalization groove 405 is provided on the front end face of the first piston 401.

[0043] As a preferred embodiment of this invention, such as Figure 1As shown in the figure, the take-off housing 101 is provided with a shift fork shaft 102, the front end of the shift fork shaft 102 is in contact with the rear end of the first piston 401, and the front end of the shift fork shaft 102 is provided with an air gap 14, and the first vacuum cavity 7 is connected with the vacuum channel 404 through the air gap 14.

[0044] As a preferred scheme of the embodiment, as shown in the figure, Figure 1 As shown in the figure, the first atmospheric vent 12 is provided with a first vent valve 15.

[0045] As shown in the figure, Figure 1 As shown in the figure, the second atmospheric vent 13 is provided with a second vent valve 16.

[0046] As a preferred scheme of the embodiment, as shown in the figure, Figure 1 As shown in the figure, the take-off body 1 further comprises a gear shifting fork 103, and the gear shifting fork 103 is coaxially sleeved on the shift fork shaft 102.

[0047] As shown in the figure, Figure 1 Further comprising a compression spring 104, the compression spring 104 is coaxially sleeved on the shift fork shaft 102, and the compression spring 104 is located at the rear end of the gear shifting fork 103.

[0048] As shown in the figure, Figure 1 Further comprising a gear shifting sleeve 105, the gear shifting sleeve 105 can reciprocate along the axial direction under the driving of the gear shifting fork 103.

[0049] As a preferred scheme of the embodiment, as shown in the figure, Figure 1 As shown in the figure, the shift fork shaft 102 and the take-off housing 101 are provided with a first sealing ring 17.

[0050] As shown in the figure, Figure 1 As shown in the figure, the take-off housing 101 and the first piston 401 are provided with a second sealing ring 18.

[0051] As shown in the figure, Figure 1 As shown in the figure, the cylinder body 2 and the middle section 402 of the piston shaft are provided with a third sealing ring 19.

[0052] As shown in the figure, Figure 1 As shown in the figure, the cylinder body 2 and the second piston 6 are provided with a fourth sealing ring 20.

[0053] In the embodiment, since the take-off is in the gear shifting work, the axial air pressure of the first piston 401 and the second piston 9 is not equal and needs to be kept, and therefore the sealing ring is used to ensure the sealing property.

[0054] The specific use process of the device in the utility model is as follows:

[0055] The vacuum interface 11 on the whole vehicle vacuum air pipe and the power take-off housing 101 is connected in communication and provides vacuum negative pressure, which is in turn passed through the vacuum interface 11, the first vacuum cavity 7, the vacuum gap 14, the vacuum channel 404, and enters the second vacuum cavity 9, so that the axial rear end of the first piston 401 and the axial rear end of the second piston 6 have vacuum negative pressure at the same time. The first atmospheric vent 12 on the cylinder body 2 and the second atmospheric vent 13 on the cylinder head 3 can be in communication with the atmosphere, so that the axial front end of the first piston 401 and the axial front end of the second piston 6 have atmospheric pressure, that is, the first atmospheric cavity 8 and the second atmospheric cavity 10 have atmospheric pressure.

[0056] When the power take-off needs to work, the first vacuum cavity 7 and the second vacuum cavity 9 are connected to the whole vehicle vacuum air through the vacuum interface 11 on the power take-off housing 101 to form vacuum negative pressure, that is, the axial rear end of the first piston 401 and the axial rear end of the second piston 6 have vacuum negative pressure; at the same time, the first atmospheric cavity 8 and the second atmospheric cavity 10 are both atmospheric pressure, that is, the axial front end of the first piston 401 and the axial front end of the second piston 6 are atmospheric pressure, and are greater than the air pressure of the axial rear end of the first piston 401 and the axial rear end of the second piston 6. Under the action of the pressure difference, the piston shaft 4 and the second piston 6 together push the fork shaft 102 to drive the gear shifting fork 103 hung on it to move to the axial rear end and press the compression spring 104; at the same time, the gear shifting sleeve 105 slides to the axial rear end under the action of the gear shifting fork 103 and engages with the outer spline of the output gear, realizing the gear engagement operation of the power take-off.

[0057] When the power take-off does not need to work, the electromagnetic valve is closed to disconnect the whole vehicle vacuum negative pressure, and the first vacuum cavity 7 in the power take-off housing 101 and the second vacuum cavity 9 in the cylinder body 2 are both in communication with the atmosphere, so that the axial sides of the first piston 401 and the second piston 6 have equal air pressure; at this time, the compression spring 104 pushes the gear shifting fork 103 under the action of the spring force after the spring is compressed, and the gear shifting fork 103 drives the gear shifting sleeve 105 to move to the axial front end and disengage from the outer spline of the output gear, realizing the gear disengagement operation of the power take-off.

Claims

1. A double-piston negative pressure gear-hanging device for a power take-off, comprising a power take-off body (1) including a power take-off shell (101), a cylinder body (2) mounted on the front side of the power take-off shell (101), and a cylinder cover (3) mounted on the front side of the cylinder body (2); and a piston shaft (4), characterized in that: the piston shaft (4) comprises a first piston (401), a piston shaft middle section (402), and a piston shaft front section (403) coaxially arranged and integrally formed, the piston shaft middle section (402) is mounted on the cylinder body (2) and can reciprocate in the axial direction, and the piston shaft front section (403) coaxially sleeves a second piston (6) through a stop ring (5). the first piston cavity between the power take-off shell (101) and the cylinder body (2) is a first vacuum cavity (7) in which the first piston (401) is located, the first piston cavity between the first piston (401) and the power take-off shell (101) is a first atmospheric cavity (8) between the first piston (401) and the cylinder body (2); the second piston cavity between the cylinder body (2) and the cylinder cover (3) is a second vacuum cavity (9) in which the second piston (6) is located, and the second piston cavity between the second piston (6) and the cylinder cover (3) is a second atmospheric cavity (10) between the second piston (6) and the cylinder cover (3); the power take-off shell (101) is provided with a vacuum interface (11) communicating with the first vacuum cavity (7), and the piston shaft (4) is further provided with a vacuum channel (404) for communicating the first vacuum cavity (7) with the second vacuum cavity (9); the cylinder body (2) is provided with a first atmospheric vent (12) communicating with the first atmospheric cavity (8), and the cylinder cover (3) is provided with a second atmospheric vent (13) communicating with the second atmospheric cavity (10). the front end surface of the first piston (401) is provided with an annular pressure equalization groove (405).

2. The dual piston negative pressure gear engagement device for a power takeoff according to claim 1, characterized by, the power take-off shell (101) is provided with a shift fork shaft (102), the front end of the shift fork shaft (102) is in contact with the rear end of the first piston (401), the front end of the shift fork shaft (102) is provided with a vacuum gap (14), and the first vacuum cavity (7) communicates with the vacuum channel (404) through the vacuum gap (14).

3. The dual piston negative pressure gear engagement device for a power takeoff as set forth in claim 1, characterized by, the first atmospheric vent (12) is provided with a first vent valve (15); 4. The dual piston negative pressure gear engagement device for a power takeoff as set forth in claim 1, wherein the second atmospheric vent (13) is provided with a second vent valve (16). the power take-off body (1) further comprises a gear-hanging shift fork (103) coaxially sleeved on the shift fork shaft (102); 5. The dual piston negative pressure gear engagement device for a power takeoff as set forth in claim 1, wherein the power take-off body (1) further comprises a compression spring (104) coaxially sleeved on the shift fork shaft (102), and the compression spring (104) is located at the rear end of the gear-hanging shift fork (103); the power take-off body (1) further comprises a gear-hanging sliding sleeve (105) capable of reciprocating in the axial direction under the driving of the gear-hanging shift fork (103). ​ 6. The dual piston negative pressure gear engagement device for a power takeoff as set forth in claim 5, wherein The first sealing ring (17) is arranged between the shift fork shaft (102) and the power take-off housing (101); The second sealing ring (18) is arranged between the power take-off housing (101) and the first piston (401); The third sealing ring (19) is arranged between the cylinder body (2) and the middle section of the piston shaft (402); The fourth sealing ring (20) is arranged between the cylinder body (2) and the second piston (6).

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