Engineering vehicle shifting device with buffer mechanism

Abstract

A shifting device for an engineering vehicle with a buffer mechanism comprises a valve body, an oil inlet and an oil outlet are arranged in the valve body, a connecting passage is arranged between the oil inlet and the oil outlet, one end of the connecting passage passes through the outer surface of the valve body, a piston rod is arranged in the connecting passage, the piston rod is provided with an oil passage that can connect the oil inlet or the oil outlet, a control rod is arranged on the piston rod, the diameter of the control rod is smaller than the diameter of the piston rod, a control cover is arranged on the outer surface of the valve body, a blind hole is arranged in the control cover, a control spring is sleeved on the control rod, one end of the control spring abuts on the end face of the piston rod, the other end of the control spring abuts on the bottom face of the blind hole, and a microchannel connecting the two ends of the oil inlet is arranged on the piston rod. Since the shifting mechanism of the present invention is provided with the buffer mechanism, the service life of the power transmission mechanism part of the engineering vehicle can be extended, and the driving comfort and controllability of the engineering vehicle can be improved.

Description

Technical Field

[0001] The present invention relates to a buffer mechanism, and more particularly to a buffer mechanism for a gear shifting device of an engineering vehicle. Background Art

[0002] Engineering vehicles need to frequently switch between forward and reverse when working. The engineering vehicles in the prior art have the following defects when switching between forward and reverse: the vehicle shakes violently and emits a large impact noise. These two defects seriously affect the service life of the power transmission mechanism of the engineering vehicle and the driving comfort and controllability of the engineering vehicle driver. Summary of the invention

[0003] In order to overcome the above defects, the technical problem to be solved by the present invention is: to provide a buffer mechanism of a shift device which can prolong the service life of a power transmission mechanism of an engineering vehicle and improve the driving comfort and controllability of the engineering vehicle.

[0004] The technical solution of the present invention to solve the problems existing in the prior art is: a shift device for an engineering vehicle with a buffer mechanism, which includes a valve body of the shift device, wherein an oil inlet, an oil outlet and a switching valve are arranged in the valve body, one end of the oil inlet is connected to one end of the oil outlet through the switching valve, the other end of the oil inlet is connected to a hydraulic pump for outputting high-pressure hydraulic oil of the engineering vehicle, and the other end of the oil outlet is connected to a clutch in the shift device, a connecting channel is further arranged between the oil inlet and the oil outlet, an end of the connecting channel closer to the outer surface of the valve body extends outward and passes through the outer surface of the valve body, and a movable member is arranged in the connecting channel which can slide back and forth along the connecting channel A piston rod, wherein the piston rod is provided with an oil passage at the position of the oil inlet or the oil outlet, which can connect the two ends of the oil inlet or the oil outlet, the piston rod is provided with a control rod in the same direction as the extending direction of the connecting passage, the diameter of the control rod is smaller than the diameter of the piston rod, the outer surface of the valve body is provided with a control cover at the position of the connecting passage, the control cover is provided with a blind hole, the outer peripheral surface of the control rod is sleeved with a control spring, one end of the control spring abuts on the end surface of the piston rod facing the control spring, and the other end of the control spring abuts on the bottom surface of the blind hole, and the piston rod or the valve body is provided with a microchannel connecting the two ends of the oil inlet or the oil outlet.

[0005] We know that the power transmission mechanism of engineering vehicles is generally composed of a clutch, a gearbox, a universal transmission device, a main reduction gearbox, a differential and a half shaft, etc. The function of the gear shifting device we usually call is completed by the clutch and the gearbox. The switching between forward and backward of the engineering vehicle requires the two friction plates in the clutch to be continuously separated and engaged. The clutch is achieved by controlling the on and off of the hydraulic oil by the solenoid valve. After careful research, the inventor believes that due to the rapid on and off of the solenoid valve, the two friction plates are instantly completed from zero load in the separated state to full load in the engaged state. The engineering vehicle suddenly starts from a stopped state and enters the forward or backward state, resulting in violent shaking. The meshing gears of the gearbox also instantly reach full load from zero load, thereby generating a large impact noise. These two problems existing in the prior art engineering vehicles seriously affect the service life of the power transmission mechanism part and the driving comfort and controllability of the engineering vehicle driver.

[0006] The working process of the clutch and gearbox in engineering vehicles is as follows: when the engineering vehicle is in a stopped state, the two friction plates are in a separated state, and the oil pressure at the oil outlet is zero. When the engineering vehicle needs to be started, the solenoid valve is started first, and the high-pressure hydraulic oil enters the oil outlet from the oil inlet through the solenoid valve. When the oil pressure at the oil outlet rises to a level that can overcome the resistance generated by the movement of the friction plates, the two friction plates are pushed closer together. When the two friction plates touch, the friction plates are blocked and no longer move. The oil pressure at the oil outlet will continue to rise until it reaches the rated oil pressure. As the oil pressure continues to rise, the two friction plates are pushed to produce a mutual squeezing force, thereby generating a friction force that can transmit power torque. When the friction force is large enough to overcome the critical resistance generated when the engineering vehicle is about to start, the power torque transmitted by the two friction plates begins to drive the meshing gears in the gearbox to rotate, and the engineering vehicle begins to move and gradually accelerates.

[0007] Therefore, the present invention adopts a buffer mechanism between the oil inlet and the oil outlet. The oil passage in the buffer mechanism can be set at the oil outlet or at the oil inlet. In order to improve the feedback sensitivity of the buffer mechanism to the increase of oil pressure, it is preferred to set the oil passage at the oil inlet, and the preload force of the control spring in the buffer mechanism is set to the driving force generated by the oil pressure required to overcome the critical resistance when the engineering vehicle is about to start, which pushes the piston rod away from the end face of one side of the control spring; the switching valve can be a cylinder valve or a solenoid valve, and the present invention preferably uses a solenoid valve. When the engineering vehicle needs to be started, the driver of the engineering vehicle first selects the forward gear or reverse gear according to the engineering needs, and then turns on the solenoid valve switch. The valve core on the solenoid valve moves, and the through hole on the valve core connects the oil inlet and the oil outlet of the valve body. The high-pressure hydraulic oil in the oil pump continuously flows from the oil inlet through the valve core into the oil outlet. The oil pressure at the oil outlet begins to build up and gradually rises. When the oil pressure at the oil outlet reaches and exceeds the resistance that can be overcome for the friction plate to move, the friction plate begins to move, and the distance between the two friction plates gradually decreases. When the two friction plates contact, the friction plate no longer moves. As the high-pressure hydraulic oil continues to be input, the oil pressure continues to rise, and power begins to be transmitted between the two friction plates. When the power transmitted between the friction plates is large enough to overcome the resistance that needs to be overcome for the engineering vehicle to start, the engineering vehicle starts to start. At this time, the oil pressure at the oil outlet acts on the piston rod The pushing force generated by the end face away from the control spring is equal to the preload force of the control spring. As the oil pressure at the oil outlet continues to rise, the pushing force generated by the oil pressure at the oil outlet on the end face of the piston rod away from the control spring is greater than the preload force of the control spring. The oil pressure at the oil outlet begins to push the piston rod to the side of the control spring, and the oil passage on the piston rod begins to enter the connecting channel. The flow of high-pressure hydraulic oil in the oil passage begins to decrease, causing the rising speed of the oil pressure at the oil outlet to gradually slow down. When the moving speed of the engineering vehicle accelerates to the rated value, the pushing force generated by the oil pressure at the oil outlet on the end face of the piston rod away from the control spring just pushes the entire oil passage on the piston rod into the connecting channel. At this time, the microchannel on the piston rod is at the oil inlet position, and the flow of high-pressure hydraulic oil through the microchannel at the oil inlet is equal to the pressure-maintaining flow at the oil outlet. In this way, it can ensure that the engineering vehicle runs smoothly and energy-saving when moving forward or backward. The shift mechanism of the present invention controls the flow rate of high-pressure hydraulic oil by cleverly arranging the buffer mechanism, thereby ensuring that the oil pressure rises rapidly before the engineering vehicle starts, and the oil pressure rise rate gradually slows down after starting until the speed of the engineering vehicle reaches the rated value. This can not only ensure the rapid starting of the engineering vehicle, but also make the engineering vehicle accelerate smoothly and gently after starting, so as to avoid the violent shaking of the engineering vehicle when starting and the emission of large impact noise in the prior art, thereby improving the driving comfort and controllability of the engineering vehicle driver, and at the same time reducing the impact stress of the transmission mechanism and extending the service life of the power transmission mechanism of the engineering vehicle.The microchannel of the present invention can be arranged on the valve body or on the piston. The microchannel of the present invention is preferably arranged on the piston. The arrangement of the microchannel in the present invention can greatly reduce the manufacturing difficulty and manufacturing cost of the control spring.

[0008] Preferably, the oil passage is an annular groove on the outer surface of the piston rod. The oil passage can be either a radial through hole provided on the piston rod or an annular groove provided on the outer surface of the piston rod. The present invention preferably uses an annular groove to facilitate machining and reduce manufacturing costs.

[0009] Preferably, the microchannel is an annular groove on the outer surface of the piston rod, and the annular groove is located on the side of the annular groove away from the spring. The microchannel can be a radial through hole set on the piston rod, an oil hole set on the valve body, or an annular groove set on the outer surface of the piston rod. The present invention preferably sets an annular groove on the outer surface of the piston rod to facilitate machining and reduce manufacturing costs.

[0010] Preferably, the diameter of the end of the connecting channel opposite to the extending direction of the connecting channel is smaller than the diameter of the connecting channel, so that a step surface is generated in the connecting channel, which is beneficial to the positioning of the piston rod and the preset control of the spring preload.

[0011] Preferably, the diameter of the blind hole is smaller than the diameter of the connecting passage, so that a step surface can be produced to ensure that the control spring will not fail due to excessive compression of the piston rod.

[0012] Beneficial effect: Since the shift mechanism of the present invention is provided with a buffer mechanism, the flow rate of the high-pressure hydraulic oil is controlled by the cleverly arranged buffer mechanism to ensure that the oil pressure rises quickly before the engineering vehicle starts, and the oil pressure rise rate gradually slows down after starting until the speed of the engineering vehicle reaches the rated value. This can not only ensure the rapid start of the engineering vehicle, but also make the engineering vehicle accelerate smoothly and gently after starting, so as to avoid the violent shaking of the engineering vehicle when starting in the prior art and the emission of large impact noise, thereby improving the driving comfort and controllability of the engineering vehicle driver, and at the same time reducing the impact stress of the transmission mechanism and extending the service life of the power transmission mechanism of the engineering vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention;

[0014] Figure 2 yes Figure 1 AA cross-sectional view in FIG.

[0015] Figure 3 yes Figure 2 The R part is enlarged in the figure;

[0016] Figure 4 yes Figure 3 Schematic diagram of the M part in the

[0017] Figure 5 It is a structural schematic diagram of the piston rod in the present invention.

[0018] In the figure: 1: valve body, 2: solenoid valve, 3: piston rod, 4: oil inlet, 5: oil outlet, 6: annular groove, 7: annular groove, 8: control spring, 9: control rod, 10: retaining ring, 11: sealing ring, 12: adjusting shaft, 13: strip groove, 14: adjusting member, 15: threaded shaft, 16: baffle, 17: control cover, 18: connecting channel, 19: blind hole. DETAILED DESCRIPTION

[0019] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0020] Embodiment: A shifting device for an engineering vehicle with a buffer mechanism, as shown in the figure, comprises a valve body 1 of the shifting device, wherein an oil inlet 4, an oil outlet 5 and a solenoid valve 2 are arranged in the valve body 1, wherein the oil inlet 4 and the oil outlet 5 are arranged in parallel and are both connected to the solenoid valve 2, and in order to improve the feedback sensitivity of the buffer mechanism to the increase in oil pressure, the oil inlet 4 is arranged on a side close to the outer surface of the valve body 1, and the solenoid valve 2 controls the on-off between the oil inlet 4 and the oil outlet 5 by pushing and pulling the valve core to move the channel position arranged on the valve core, and a connecting channel 18 is also arranged between the oil inlet 4 and the oil outlet 5, and the connecting channel 18 extends outward at an end closer to the outer surface of the valve body 1 and penetrates the valve body 1 outer surface, the diameter of the connecting channel 18 at the end opposite to the extending direction of the connecting channel 18 is smaller than the diameter of the connecting channel 18, a piston rod 3 is provided in the connecting channel 18 and can slide back and forth along the connecting channel 18, the piston rod 3 is provided with an annular groove 6 at the position of the oil inlet 4 so that the oil inlet 4 and the oil outlet 5 can be connected, and the piston rod is provided with an annular groove 7 on the side of the annular groove 6 close to the oil outlet, when the annular groove 6 is completely located in the oil inlet 4, the flow rate of the high-pressure hydraulic oil between the oil inlet 4 and the oil outlet 5 is the largest, when the annular groove 6 is completely away from the oil inlet 4, the annular groove 7 just enters the oil inlet 4, at this time, the oil inlet 4 and the oil outlet 5 are connected. The flow rate of high-pressure hydraulic oil between the oil ports 5 is minimal and equal to the internal leakage of the shifting device, which is beneficial to the stable pressure maintenance inside the shifting device. The piston rod 3 is provided with a control rod 9 in the same direction as the extending direction of the connecting channel 18. The diameter of the control rod 9 is smaller than the diameter of the piston rod 3. The outer surface of the valve body 1 is fixedly connected with a control cover 17 at the position of the connecting channel 18. A blind hole 19 with a diameter smaller than the diameter of the connecting channel 18 is provided in the control cover 17. A baffle 16 and an adjusting member 14 are provided in the blind hole 19. The adjusting member 14 is located between the bottom surface of the blind hole 19 and the baffle 16. The adjusting member 14 is provided with an adjusting shaft 12 on the side facing the bottom surface of the blind hole 19. The adjusting shaft 12 penetrates The control cover 17 is passed through, and a threaded shaft 15 is provided on the side of the adjusting member 14 facing the baffle 16, and the baffle 16 is screwed on the threaded shaft 15. The adjusting shaft 12 is sleeved with a sealing ring 11 in a blind hole 19 and is provided with a retaining ring 10 with a diameter larger than that of the adjusting shaft 12. The retaining ring 10 abuts against the bottom surface of the blind hole 19 through the sealing ring 11. The end of the adjusting shaft 12 facing outward is provided with a strip groove 13 for rotating the threaded shaft 15. A control spring 8 is sleeved on the outer circumferential surface of the control rod 9, and one end of the control spring 8 abuts against the end surface of the piston rod 3 facing the control spring 8, and the other end of the control spring 8 abuts against the baffle 16.

[0021] In this embodiment, a baffle plate with an adjustable axial position relative to the blind hole is provided in the blind hole, and the other end of the control spring abuts against the baffle plate. The purpose of doing so is that we know from the working process and principle analysis of the shifting device that the optimal preload force of the control spring of the present invention is equal to the driving force generated by the oil pressure required to push the piston rod away from the end face of one side of the control spring when the engineering vehicle is about to start. If the preload force of the control spring is too small, it will cause the engineering vehicle to start slowly and affect the improvement of work efficiency. If the preload force of the control spring is too large, it will cause the engineering vehicle to start too quickly and cause the vehicle to shake and make a lot of noise. It is known from the calculation formula of the spring elastic force that the elastic force of the spring is the elastic coefficient K multiplied by the deformation. Since the elastic coefficient K is related to some factors that are difficult to fully and accurately control, such as the diameter of the spring, the wire diameter of the spring, the material of the spring, the effective number of coils of the spring, etc., it is difficult to make the elastic coefficient of the spring equal and meet the specified requirements. In order to further reduce the manufacturing difficulty and manufacturing cost of the control spring, this requires us to adjust the preload force of the control spring by the deformation. The present invention provides a baffle with adjustable axial position, which is beneficial to the preset control spring preload force and ensures that the driving force generated by the oil pressure at the oil outlet on the end face of the piston rod away from the control spring when the engineering vehicle is about to start is equal to the preload force of the control spring.

[0022] In this embodiment, an adjusting member is provided in the blind hole between the bottom surface of the blind hole and the baffle, and an adjusting shaft is provided on the side of the adjusting member facing the bottom surface of the blind hole, and the adjusting shaft passes through the control cover, and a threaded shaft is provided on the side of the adjusting member facing the baffle, and the baffle is screwed on the threaded shaft, and a rotating structure that can rotate the threaded shaft is provided on the end of the adjusting shaft facing outward. The rotating structure can be a rotating handle, a square head structure, a strip groove or a cross groove, and the present invention preferably uses a strip groove. In this way, when it is necessary to adjust the axial position of the baffle in the blind hole, the threaded shaft can be easily rotated with a flat-bladed screwdriver, so as to adjust the baffle to the most suitable axial position in the blind hole.

[0023] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

[0024] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

Claims

1. A shifting device for an engineering vehicle with a buffer mechanism, comprising a valve body of the shifting device, wherein an oil inlet, an oil outlet and a switching valve are arranged in the valve body, one end of the oil inlet is connected to one end of the oil outlet through the switching valve, the other end of the oil inlet is connected to a hydraulic pump for outputting high-pressure hydraulic oil of the engineering vehicle, and the other end of the oil outlet is connected to a clutch in the shifting device, characterized in that: The oil inlet and the oil outlet are provided with a connecting passage, and the connecting passage has an end closer to the outer surface of the valve body that extends outward and passes through the outer surface of the valve body. A piston rod that can slide back and forth along the connecting passage is provided in the connecting passage. The piston rod is provided with an oil passage at the position of the oil inlet or the oil outlet that can connect the two ends of the oil inlet or the oil outlet. The piston rod is provided with a control rod in the same direction as the extending direction of the connecting passage. The diameter of the control rod is smaller than the diameter of the piston rod. A control cover is provided on the outer surface of the valve body at the position of the connecting passage. A blind hole is provided in the control cover. A control spring is sleeved on the outer circumference of the control rod. A baffle and an adjusting member are provided in the blind hole. The adjusting member is located between the bottom surface of the blind hole and the baffle. An adjusting shaft is provided on the side of the adjusting member facing the bottom surface of the blind hole, and the adjusting shaft passes through the control cover; a threaded shaft is provided on the side of the adjusting member facing the baffle, and the baffle is screwed on the threaded shaft; one end of the control spring abuts on the end surface of the piston rod facing the control spring, and the other end of the control spring abuts on the baffle; a rotating structure for rotating the threaded shaft is provided on the end of the adjusting shaft facing outward; a microchannel connecting the two ends of the oil inlet or the oil outlet is provided on the piston rod; the oil passage is an annular groove on the outer surface of the piston rod; the microchannel is an annular groove on the outer surface of the piston rod, and the annular groove is located on the side of the annular groove away from the spring; the diameter of the blind hole is smaller than the diameter of the connecting channel.

2. The engineering vehicle shifting device with a buffer mechanism according to claim 1, characterized in that: The diameter of the end of the connecting channel opposite to the extending direction of the connecting channel is smaller than the diameter of the connecting channel.

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