CN117108471A - Crankshaft direct-drive cross head reciprocating pump - Google Patents

Abstract

The invention discloses a crankshaft direct-drive crosshead reciprocating pump, wherein a crosshead is a sliding block mechanism; the crank sliding block mechanism comprises a crank for realizing driving, a piston rod connected through the sliding block mechanism, the sliding block mechanism comprises a center sliding block and a rectangular frame for limiting the sliding block to generate linear motion, and the sliding block and the rectangular frame form the crosshead; the sliding block and the rectangular frame vertically move relative to each other, the sliding block slides in the rectangular frame, the rectangular frame slides in the guide plate, and the crank is rotationally connected to the sliding block to drive the sliding block to generate circular motion so as to drive the rectangular frame to perform linear motion. According to the invention, the crank block structure is used for replacing the connecting rod in the multi-cylinder reciprocating pump, so that the whole length of the transmission mechanism is shortened, and the weight of the reciprocating pump is reduced.

Description

Crankshaft direct-drive cross head reciprocating pump

Technical Field

The invention relates to a crankshaft direct-drive cross head reciprocating pump, and relates to the technical field of reciprocating pumps.

Background

The crank-link mechanism reciprocating pump drives the link through the rotation of the crankshaft, and drives the cross head and the piston (or plunger) to realize reciprocating motion, and has the advantages of continuous and stable reciprocating reversing, high working reliability and the like. In order to ensure that the reciprocating pump has better performance, the connecting rod does not interfere with the movement process of the cross head, the ratio of the crank radius to the length of the connecting rod (called the connecting rod ratio) cannot be too large, but the connecting rod ratio is too small, and the length and the weight of the reciprocating pump can be obviously increased due to the overlong connecting rod. The connecting rod ratio of the general reciprocating pump is 1/7-1/8, namely the length of the connecting rod is 7-8 times of the radius of the crank and 3.5-4 times of the stroke of the reciprocating pump. As the reciprocating pump stroke increases, the length of the pump increases significantly.

In the prior art, patent (CN 200520076868) discloses a motion mechanism using a crank-slider mechanism instead of a connecting rod, which is shorter than the crank-link mechanism in overall length, but is applied to a double-cylinder reciprocating compressor, and is different from the conventional reciprocating pump in realization, and cannot realize the functional requirement of a multi-cylinder reciprocating pump.

Disclosure of Invention

The invention aims to provide a crankshaft direct-drive cross head reciprocating pump, which solves the problems of overlong length and heavy weight of a traditional crank-link mechanism reciprocating pump transmission mechanism.

In order to achieve the technical purpose and the technical effect, the invention is realized by the following technical scheme:

a crankshaft direct drive crosshead reciprocating pump comprising: the crank shaft is externally connected with a power source, and the cross head and the crank form a crank slide block mechanism, wherein the cross head is a slide block mechanism and comprises a slide block and a rectangular frame which are nested and fixed, and the crank shaft rotates to drive the slide block to push the rectangular frame to reciprocate in the guide plate;

the sliding blocks linearly slide in the rectangular frames, the rectangular frames linearly slide in the guide plates, and sliding tracks are mutually perpendicular;

the crank slide block mechanism comprises a crank for realizing driving, and a piston rod connected with the slide block mechanism, the slide block and the rectangular frame form the crank slide block mechanism together. Including the bent axle of external power supply, its characterized in that: the crank comprises a cross head and a crank, wherein the cross head and the crank form a crank slide block mechanism, the cross head is a slide block mechanism, and the crank rotates to drive the slide block to push the cross head to reciprocate in the guide plate;

the crosshead comprises a slider and a rectangular frame which are nested and fixed, and the slider slides in the rectangular frame in a straight line;

the crank slide block mechanism comprises a crank for realizing driving, and a piston rod connected with the slide block mechanism, the slide block and the rectangular frame form the crank slide block mechanism together;

the rectangular frame is limited to move in the direction perpendicular to the moving direction of the sliding block, and the crank is rotationally connected to the sliding block to drive the sliding block to move circularly to drive the rectangular frame to move linearly.

Further, the rectangular frame is constrained by the guide plate, and the fixing direction of the guide plate is perpendicular to the moving direction of the sliding block.

Further, a gap is formed between the piston rod and the cross head.

Preferably, the piston rod and the intermediate rod are fixed in a surrounding manner through a clamp, and the clamp is coaxially fixed with the piston rod and the intermediate rod. The medium rod is rigidly connected with the rectangular frame of the cross head, and the medium rod can be taken out by loosening the clamp for fixation.

Further, the contact surface between the sliding block and the rectangular frame is an arc surface.

Preferably, the cambered surface is a cylindrical surface, and the radian of the contact surfaces of the two parts is the same.

Further preferably, a gap is reserved between the cambered surfaces.

Further preferably, the gap is defined by a 6-8 level tolerance.

Further, a detachable structure is arranged between the sliding block and the rectangular frame.

Preferably, after the slider is mounted on the crank pin, the crankshaft is mounted on a crankshaft bearing seat on the pump body; then, the end cap is mounted on the rectangular frame body.

Further preferably, the gap between the slider and the contact cylindrical surface of the crosshead can be adjusted by adding or subtracting shims between the end surfaces of the end caps and the rectangular frame body that are in contact.

Further, when the reciprocating pump is three cylinders, the phase angle of the adjacent two cranks is 120 degrees.

Further, when the reciprocating pump is five cylinders, the phase angle of adjacent two cranks is 144 degrees.

Further, when the reciprocating pump is a seven-cylinder pump, the phase angle of the adjacent two cranks is 154.3 degrees.

The invention has the beneficial effects that:

according to the invention, a crank sliding block structure is used for replacing a connecting rod in the multi-cylinder reciprocating pump, so that the whole length of a transmission mechanism is shortened, the weight of the reciprocating pump is reduced, and a medium rod is additionally arranged in consideration of the use condition and the service life; and the contact surface between the sliding block and the rectangular frame is an arc surface. Gaps are reserved between the cambered surfaces, so that the vertical error between the crankshaft rotation center line and the rectangular frame axis is adapted.

Of course, it is not necessary for any one product to practice the invention to achieve all of the advantages set forth above at the same time.

Drawings

FIG. 1 is a schematic diagram of the operation of a crankshaft direct drive crosshead reciprocating pump according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a crankshaft direct drive cross-head reciprocating pump according to embodiment 1 of the present invention;

FIG. 3 is a schematic three-dimensional structure of a rectangular frame assembly according to embodiment 2 of the present invention;

fig. 4 is a three-dimensional schematic view of a rectangular frame body structure according to embodiment 2 of the present invention;

FIG. 5 is a three-dimensional schematic view of an end cap structure according to embodiment 2 of the present invention;

FIG. 6 is a schematic three-dimensional view of a slider according to embodiment 2 of the present invention;

FIG. 7 is a front view and a left side view of a slider seat according to embodiment 2 of the present invention;

FIG. 8 is a front view and a left side view of a slider cover according to embodiment 2 of the present invention;

FIG. 9 is a diagram of a three cylinder reciprocating pump according to example 4 of the present invention;

FIG. 10 is a cross-sectional view of a reciprocating pump according to example 4 of the present invention;

FIG. 11 is a diagram of a five cylinder reciprocating pump according to example 4 of the present invention;

FIG. 12 is a frame construction diagram of a five-cylinder reciprocating pump according to embodiment 4 of the present invention;

FIG. 13 is a diagram of a seven-cylinder reciprocating pump according to example 4 of the present invention;

in the accompanying drawings:

1-a pinion gear; 2-a large gear; 3-a crankshaft; 400-sliding blocks; 500-rectangular frames; 600-pump body; 7-medium rod; 8-clamping hoop; 9-a piston rod; 10-cylinder sleeve; 11-a piston; 12-an inhalation valve; 13-a liquid inlet pipe; 14-a liquid discharge pipe; 15-a discharge valve; 16-guide plates; 17-a pump head; 18-an input shaft; 19-a shield; 20-large gear and 21-small gear; 401-a slider seat; 402-a slider cover; 403-bolts; 501 a rectangular frame body; 502-end caps; 503-bolts; 601-a pump head support plate; 602-a middle riser; 603-middle riser; 604-side riser; 605-upper oblique side plate; 606-cover plate; 607-top plate; 608-rear side plate; 609-upper bracket of guide plate; 610-a guide plate lower bracket; 611-a bottom plate; 612-a bearing cap; 613-bolts; 614-crankshaft bearing blocks; 615-sloping floor; 616-input shaft bearing housing; 617-perforated baffle; 618-side uprights; 619-stent;

Detailed Description

The invention discloses a crankshaft direct-drive crosshead reciprocating pump, wherein a crankshaft directly rotates a sliding block to push a crosshead to move in a guide plate, and the crosshead and a crank form a crank sliding block mechanism, wherein the crosshead is a sliding block mechanism; the overall length is shorter than conventional reciprocating pumps.

The crank sliding block mechanism comprises a crank for realizing driving, the crank is externally connected with a power source, a piston rod is connected through the sliding block mechanism, the sliding block mechanism comprises a rectangular frame for limiting the sliding block to generate linear motion, and the sliding block and the rectangular frame form the crosshead;

referring to the schematic diagram shown in fig. 1, the slider 400 and the rectangular frame replace a connecting rod in a conventional crank-connecting rod mechanism reciprocating pump, the rotation center of the crankshaft 3 is located at the middle position of the reciprocating displacement of the rectangular frame 500, the crankshaft rotates to drive the slider to perform circular motion, and under the limitation of the rectangular frame, the rectangular frame is used as a reference to perform up-and-down reciprocating motion relative to the rectangular frame, and similarly, the rectangular frame is driven to perform linear reciprocating motion in the limited area thereof.

Compared with the connecting rod transmission, the structure transmission system of the invention has shorter distance, taking a drilling reciprocating pump with the stroke of 10 ' as an example, the radius of gyration of the crankshaft 3 is 5 ', if the connecting rod ratio is 1/7, the connecting rod length of the traditional crank-connecting rod mechanism reciprocating pump is 35 ', if the stroke of the reciprocating pump of the crankshaft direct-drive cross head of the invention is 10 ', the length can be reduced by 35 ' (889 mm) compared with the traditional crank-connecting rod mechanism reciprocating pump; the length is obviously reduced, the size of the machine seat is greatly reduced, the weight of the whole machine is obviously reduced, and the portability of the reciprocating pump can be greatly improved.

As described above, the direction of the acting force of the slider 400 on the rectangular frame 500 is always along the normal direction of the contact surface, that is, the moving direction of the rectangular frame 500, so that the conventional crank-link mechanism reciprocating pump is equivalent to the infinite length of the link, the link ratio is zero, and the performance of the crank direct-drive crosshead reciprocating pump of the present invention is not affected by the link ratio.

In order to more clearly describe the technical scheme of the embodiment of the present invention, the embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

In this embodiment, the split hole of the slider 400 is mounted on the crank pin of the crankshaft 3 and can rotate relatively around the axis of the crank pin, and two rectangular surfaces parallel to the split surface of the slider 400 are respectively attached to the long sides of the rectangular hole of the rectangular frame 500. The outer cylindrical surface of the rectangular frame 500 is mounted on the guide plate 16 and is restrained between guide plates, moving in the direction of the guide plate 16.

Referring to the structure shown in fig. 2, a side of the rectangular frame 500 near the pump head 17 is fixedly connected with the intermediate rod 7, and the intermediate rod 7 is fixedly connected with the piston rod 9. This embodiment allows the crosshead 500 and piston 11 to better accommodate the coaxiality error of the guide plate 16 and cylinder liner 10 by using a dielectric rod, which introduces more flexibility on the side connected to the rectangular frame. For example, an adjustment device may be incorporated on the rod for adjusting the length or position of the piston rod, thereby changing the operating characteristics of the pump or adapting to different operating conditions. Moreover, the invention eliminates the link mechanism, so that the slider mechanism used for replacing improves the stress condition of the cross head.

Compared with the traditional connecting rod structure, the piston rod is always subjected to axial force, and the crank sliding block mechanism has different stress conditions when pushing the piston rod, namely, when the sliding block is positioned at different positions of the rectangular frame, tiny torque can be generated on the piston rod to influence the stability of the piston rod. The addition of the medium rod in this embodiment not only facilitates adjustment and disassembly, but also plays a role in middle transmission force between the sliding block mechanism and the piston rod, and helps to disperse stress concentrated on the contact surface of the sliding block and the rectangular frame by changing the transmission path of force, so that torque (or understood as axial deviation between the thrust of the sliding block and the piston rod) is eliminated. This is because the points of action of the forces are increased and distributed more evenly, which reduces the pressure at the individual points of contact.

In particular, the design of the intermediate lever allows the force to be transmitted no longer directly from the slide to the piston rod, but rather to be relayed through the intermediate lever, thus forming a more complex force transmission chain. In this chain, the force transmission path is increased, so that the force can be distributed on more contact points, thereby reducing the stress of each contact point and improving the overall stability and durability.

In particular, in some embodiments, the intermediate rod and the piston rod are fixed or fixed in a structure with adjustable tightness, and the tightness is manually adjusted after the overall stress caused by the abrasion of the sliding block is changed, so that the service life of the device is prolonged.

In a preferred embodiment, the piston rod and the intermediate rod are fixed in a surrounding manner by a clamp, and the clamp is fixed coaxially with the piston rod and the intermediate rod. The medium rod is rigidly connected with the rectangular frame of the rectangular frame, and the medium rod can be fixed by loosening the clamp and then taken out.

Example 2

The difference between the slider and the rectangular frame structure in the foregoing embodiment is that the cambered surface in this embodiment is a cylindrical surface, and the radian of the contact surfaces of the two parts is the same. Those skilled in the art will appreciate that the self-tuning of cylindrical surface contact, and thus, the better performance, is achieved.

In a preferred embodiment of this embodiment, a gap is reserved between the cambered surfaces. The contact surface of the sliding block 400 and the rectangular frame 500 adopts cylindrical surfaces, the nominal diameters of the cylindrical surfaces are the same (namely R in the figure), and the cylindrical surfaces are in small clearance fit, and the contact of the cylindrical surfaces can well adapt to the vertical error between the rotation center line of the crankshaft and the axis of the rectangular frame. The structure thereof can be understood with reference to fig. 3-8.

In the traditional link mechanism, force is transmitted to the cross head through the link, the connecting part of the link and the cross head is in pin shaft connection, the diameter of the pin shaft is smaller, the curvature radius of the contact surface is smaller, the contact stress is larger, the abrasion of the connecting part of the link and the pin shaft is fast, and the service life is short. However, in the slider mechanism, since the contact between the slider and the rectangular frame is made by an arc surface having a larger diameter, the radius of curvature of the contact portion is large, and the contact area is also larger than that of the connecting rod, the contact stress on the slider mechanism is small, and the wear resistance is better.

Those skilled in the art will readily appreciate that: when the two cylindrical surfaces are in contact, even if the crankshaft rotation center line and the rectangular frame axis have vertical errors due to the small clearance, the sliding block and the rectangular frame can still keep good contact through relative sliding. This is the self-tuning described above. Such self-tuning can to some extent counteract vertical errors due to manufacturing, assembly, wear and the like.

Furthermore, this small clearance fit cylindrical contact design also helps reduce wear of the contact surface, and thus may allow lubricant to enter the contact surface, thereby reducing friction and wear. Considering that excessive vertical errors may result in uneven force transmission, increasing stress at part of the contact points, thereby accelerating wear. In a preferred embodiment, therefore, the gap range may be determined by IT6-IT8 class tolerances.

The related structure of the intermediate lever described in connection with embodiment 1 is similar to the present embodiment, and in some embodiments, a gap may be reserved between the intermediate lever and the piston rod to adapt to different changing situations.

In one embodiment, the slider 400 includes a slider seat 401, a slider cover 402, and a bolt 403; the joint surfaces of the sliding block seat 401 and the sliding block cover 402 are provided with positioning rabbets which are mutually embedded, and the positioning rabbets are assembled into a whole and then finish machining is carried out on the hole surface and the arc surface; the joint surface of the slider seat 401 and the slider cover 402 passes through the center line of the hole.

The rectangular frame 500 comprises a rectangular frame body 501, an end cover 502 and bolts 503; the contact part of the rectangular frame body 501 and the guide plate 16 adopts a cylindrical surface structure, and the axis of the cylindrical surface is along the moving direction of the rectangular frame 500;

a rectangular groove with a notch is formed in the middle of the rectangular frame body 501, the length of the short side of the groove is determined according to the diameter of an arc surface of the slider 400, which is in contact with the rectangular frame 500, and the length of the long side of the groove is determined by the distance between the two end surfaces of the slider 400, which are parallel to the hole axis, and the rotation diameter of a crankshaft;

the contact part of the end cover 502 and the rectangular frame body 501 is a plane, and reinforcing ribs can be arranged on the outer side; the rectangular frame body 501 and the end cover 502 are connected into a whole through bolts 503.

When the rectangular frame 500 moves towards one side of the pump head 17 during operation, the sliding block 400 generates thrust on the arc surface of the groove on the rectangular frame body 501 under the pushing of the crank pin of the crank shaft 3 so as to realize the liquid discharging process of the reciprocating pump; when the rectangular frame 500 moves reversely, the sliding block 400 acts a pushing force on the end cover 502 of the rectangular frame 500 to realize the liquid suction process of the reciprocating pump; for a single-action reciprocating pump, since the working resistance to be overcome in the liquid suction process is mainly the friction force on the piston 11 and the rectangular frame 500, the working resistance to be overcome in the liquid discharge process is very small compared with that in the liquid discharge process, the load on the end cover 502 of the rectangular frame 500 is very small, and the bolt 503 is not required to be too large in size.

The slider 400 is pre-mounted to the crank pin of the crankshaft 3 during assembly of the reciprocating pump; a sliding bearing or a rolling bearing may be used between the slider 400 and the crankpin of the crankshaft 3.

Example 3

The mechanism described in the foregoing embodiments should be easy to disassemble, so in this embodiment a detachable structure is provided between the slider and the rectangular frame.

In a preferred embodiment, the slider is mounted on the crank pin and then the crankshaft is mounted on a crankshaft bearing block on the pump body; then, the end cap is mounted on the rectangular frame body.

When in use, the rectangular frame body 501 is firstly arranged in the guide plate 16, then the crankshaft 3 is arranged on the pump body 600, and finally the end cover 502 is arranged on the rectangular frame body 501 by bolts 503; because of no connecting rod with large weight and size, the moment required by the disc pump in the assembly process of the reciprocating pump is small, the disc pump is easy and convenient to assemble.

In another preferred embodiment, the gap between the slider and the cylindrical surface of the rectangular frame can be adjusted by adding or subtracting shims between the end caps and the end surfaces of the rectangular frame body that are in contact.

When in use, the gap is adjusted according to different running conditions. For example, when a reciprocating pump is required to operate at high speed, a larger gap is required due to thermal expansion; while at low speeds, smaller clearances may be acceptable. The gap can be conveniently adjusted by adjusting the thickness of the gasket so as to adapt to different running conditions.

In addition, the gasket can compensate for such wear during operation, maintaining good contact conditions.

Example 4

In this embodiment, the crankshaft obtains power through gears. The transmission path is understood by referring to fig. 9, and after the input shaft 18 obtains the input torque, the pinion gears 1 and 21 are driven to rotate, and then the bull gears 2 and 20 are driven to rotate, so that the crankshaft 3 is driven to rotate. The distance between the center line of the crank pin on the crankshaft 3 and the center line of the main journal is the turning radius of the crankshaft, and when the crankshaft 3 rotates, the crank pin drives the sliding block 400 to revolve around the turning center of the crankshaft, and the sliding block 400 simultaneously rotates around the center of the crank pin, so that the contact part of the sliding block 400 and the cross head 500 is always in a fixed direction.

The guide plates 16 are of the same structure as the guide plates of a conventional crank-link mechanism reciprocating pump, are mounted on the pump body 600 by means of bolt connection, each rectangular frame 500 is in contact with one guide plate 16 up and down, and the center line of the cylindrical surface of the guide plate 16 coincides with the center line of the cylinder sleeve 10.

The pump body can be of any similar structure to that of the pump body commonly used in the prior art, but the crankshaft mounting position on the pump body is moved to the middle position of the guide plate 16 due to the fact that no connecting rod in the prior reciprocating pump exists, and the structure of the pump body is greatly changed relative to that of the prior reciprocating pump. For a better illustration, the present embodiment is described with reference to fig. 10:

the crankshaft 3, the intermediate rod 7, the clamp 8, the piston 9, the cylinder sleeve 10, the piston 11, the suction valve 12, the liquid inlet pipe 13, the liquid outlet pipe 14, the discharge valve 15, the pump head 17 and the input shaft 18 are the same as a traditional crank-link mechanism reciprocating pump.

The pump body 600 comprises a pump head support plate 601, middle vertical plates 602 and 603, side vertical plates 604 and 618, an upper oblique side plate 605, a cover plate 606, a top plate 607, a rear side plate 608, a guide plate upper bracket 609, a guide plate lower bracket 610, a bottom plate 611, a bearing cover 612, bolts 613, a crankshaft bearing block 614, an oblique bottom plate 615, an input shaft bearing block 616, a perforated baffle 617 and a bracket 619; the middle vertical plates 602, 603 and the side vertical plates 604, 618 are in the same shape and thickness, and are welded with the pump head supporting plate 601, the upper inclined side plate 605, the cover plate 606, the top plate 607, the rear side plate 608, the bottom plate 611, the inclined bottom plate 615 and the perforated baffle 617, so that the base forms a rigid whole; the middle support is positioned right above the center of the hole of the crankshaft bearing seat 614 in the reciprocating pump in the upper support 609 of the guide plate and the lower support 610 of the guide plate; threaded holes are formed in the upper guide plate bracket 609 and the lower guide plate bracket 610 for fixing the guide plate 16.

The number of the crankshaft bearing seats 614 is determined according to the number of cylinders of the reciprocating pump; during assembly, after the crankshaft 3 is mounted in the crankshaft bearing housing 614, the bearing cap 612 is fixed to the crankshaft bearing housing 614 by bolts 613.

In one embodiment, with specific reference to FIG. 9, a three cylinder pump is provided with two adjacent cranks at 120 degrees.

In a specific embodiment, with specific reference to fig. 11-12, a five cylinder pump is provided with two adjacent cranks at a phase angle of 144 °.

In one embodiment, the particular configuration is shown with reference to FIG. 13 as a seven cylinder pump with two adjacent cranks at a phase angle of 154.3.

In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended only to assist in the explanation of the invention. The preferred embodiments are not exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand and utilize the invention. The invention is limited only by the claims and the full scope and equivalents thereof.

Claims (10)

1. The utility model provides a bent axle directly drives cross head reciprocating pump, includes the bent axle of external power supply, its characterized in that: the crank comprises a cross head and a crank, wherein the cross head and the crank form a crank slide block mechanism, the cross head is a slide block mechanism and comprises a slide block and a rectangular frame which are nested and fixed, and the crank shaft rotates to drive the slide block to push the rectangular frame to reciprocate in a guide plate;

the sliding blocks linearly slide in the rectangular frames, the rectangular frames linearly slide in the guide plates, and sliding tracks are mutually perpendicular;

the crank slide block mechanism comprises a crank for realizing driving, and a piston rod connected with the slide block mechanism, the slide block and the rectangular frame form the crank slide block mechanism together.

2. The crankshaft direct drive crosshead reciprocating pump of claim 1, wherein: the rectangular frame is restrained by the guide plate, and the fixing direction of the guide plate is perpendicular to the moving direction of the sliding block.

3. The crankshaft direct drive crosshead reciprocating pump according to claim 1 or 2, wherein: a gap rod is arranged between the piston rod and the cross head.

4. A crankshaft direct drive crosshead reciprocating pump according to claim 3, wherein: the contact surface between the sliding block and the rectangular frame is an arc surface.

5. The crankshaft direct drive cross head reciprocating pump of claim 4, wherein: the cambered surface is a cylindrical surface, and the radian of the contact surfaces of the two parts is the same.

6. The crankshaft direct drive cross head reciprocating pump of claim 5, wherein: gaps are reserved between the cambered surfaces.

7. A crankshaft direct drive crosshead reciprocating pump according to claim 2 or 3, wherein: and a detachable structure is arranged between the sliding block and the rectangular frame.

8. The crankshaft direct drive cross head reciprocating pump of claim 7, wherein: the sliding block is detachably connected with the crankshaft through a crank pin; the rectangular frame is of a detachable structure.

9. The crankshaft direct drive cross head reciprocating pump of claim 7, wherein: and a gasket is arranged on the end surface of the sliding block, which is contacted with the rectangular frame.

10. The crankshaft direct drive crosshead reciprocating pump according to claim 1 or 2, wherein: the reciprocating pump is a 3, 5 or 7 cylinder reciprocating pump.